Fastpitch Softball Injuries: Epidemiology, Biomechanics, and Injury Prevention

PURPOSE OF REVIEW

Fastpitch softball is one of the most popular sports among youth and high school female athletes. Despite some similarities to baseball, key differences between the two sports result in different injury patterns, and there is comparatively less literature describing injury epidemiology in fastpitch softball. The purpose of this review is to describe the epidemiology, biomechanics, and injury prevention efforts in regards to fastpitch softball injury with a particular focus on underhand pitching.

RECENT FINDINGS

The injury rate in softball is relatively low and extended time loss injuries in particular are uncommon. Lower extremity injuries are more common overall in softball, but pitchers more often suffer upper extremity injury. Pitchers account for a relatively small proportion of all injuries recorded, but represent a similarly small subset of team rosters, with most teams carrying only a few pitchers in total. The underhand pitching motion exerts significant glenohumeral distractive forces and high stress across the biceps-labrum complex. Core and lower extremity strengthening play an important role in injury prevention for softball pitchers and position players. Fatigue and number of games pitched are tied to increased strength deficiencies and pain in fastpitch softball pitchers, yet pitch count limits are not employed in any major fastpitch softball leagues. While overall injury incidence is low in fastpitch softball players, the potential for overuse injury in pitchers in particular is noteworthy and not nearly as scrutinized as within the baseball community. Critical longitudinal tracking of softball injuries at varying levels of play would be helpful to better understand the sport's injury risk. There are currently no formal pitch count limits enforced in a majority of fastpitch softball leagues. Core and lower extremity strengthening, pre-season conditioning, and monitoring of pitchers for signs of fatigue may be helpful in injury prevention.

Rotator cuff tears

Rotator cuff tears are the most common upper extremity condition seen by primary care and orthopaedic surgeons, with a spectrum ranging from tendinopathy to full-thickness tears with arthritic change. Some tears are traumatic, but most rotator cuff problems are degenerative. Not all tears are symptomatic and not all progress, and many patients in whom tears become more extensive do not experience symptom worsening. Hence, a standard algorithm for managing patients is challenging. The pathophysiology of rotator cuff tears is complex and encompasses an interplay between the tendon, bone and muscle. Rotator cuff tears begin as degenerative changes within the tendon, with matrix disorganization and inflammatory changes. Subsequently, tears progress to partial-thickness and then full-thickness tears. Muscle quality, as evidenced by the overall size of the muscle and intramuscular fatty infiltration, also influences symptoms, tear progression and the outcomes of surgery. Treatment depends primarily on symptoms, with non-operative management sufficient for most patients with rotator cuff problems. Modern arthroscopic repair techniques have improved recovery, but outcomes are still limited by a lack of understanding of how to improve tendon to bone healing in many patients.

Evaluation of Spin Bias in Systematic Reviews and Meta-analyses of Rotator Cuff Repair With Platelet-Rich Plasma

BACKGROUND

The use of platelet-rich plasma (PRP) in orthopaedics continues to increase. One common use of PRP is as an adjunct in rotator cuff repair surgery. Multiple systematic reviews and meta-analyses have summarized the data on PRP use in rotator cuff repair surgery. However, systematic reviews and meta-analyses are subject to spin bias, where authors' interpretations of results influence readers' interpretations.

PURPOSE

To evaluate spin in the abstracts of systematic reviews and meta-analyses of PRP with rotator cuff repair surgery.

STUDY DESIGN

Systematic review; Level of evidence, 3.

METHODS

A PubMed and Embase search was conducted using the terms rotator cuff repair and PRP and systematic review or meta-analysis. After review of 74 initial studies, 25 studies met the inclusion criteria. Study characteristics were documented, and each study was evaluated for the 15 most common forms of spin and using the AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews, Version 2) rating system. Correlations between spin types and study characteristics were evaluated using binary logistic regression for continuous independent variables and a chi-square test or Fisher exact test for categorical variables.

RESULTS

At least 1 form of spin was found in 56% (14/25) of the included studies. In regard to the 3 different categories of spin, a form of misleading interpretation was found in 56% (14/25) of the studies. A form of misleading reporting was found in 48% (12/25) of the studies. A form of inappropriate extrapolation was found in 16% (4/25) of the studies. A significant association was found between misleading interpretation and publication year (odds ratio [OR], 1.41 per year increase in publication; 95% CI, 1.04-1.92; P = .029) and misleading reporting and publication year (OR, 1.41 per year increase in publication; 95% CI, 1.02-1.95; P = .037). An association was found between inappropriate extrapolation and journal impact factor (OR, 0.21 per unit increase in impact factor; 95% CI, 0.044-0.99; P = .048).

CONCLUSION

A significant amount of spin was found in the abstracts of systematic reviews and meta-analyses of PRP use in rotator cuff repair surgery. Given the increasing use of PRP by clinicians and interest among patients, spin found in these studies may have a significant effect on clinical practice.

Gender Disparities in Endowed Professorships Within Orthopaedic Surgery

Background Orthopaedic surgery has the lowest number of full-time faculty positions held by women, at 19%, with endowed chairs among the most coveted and advantageous. We examined the characteristics of endowed professors from the US top 100 orthopaedic academic centers and highest-funded musculoskeletal (MSK) researchers to determine if gender is associated with endowed professorship. Additionally, we sought to determine if gender is associated with increased NIH funding for top-performing musculoskeletal researchers.  Methods Our primary study group included the top 100 orthopaedic academic centers defined by US News World Report and Doximity's rankings. Our secondary study group examined the top MSK researchers, defined as principal investigators, who received >$400,000 in annual NIH funding from 2018 to 2021. Orthopaedic departments included MSK researchers and subspecialties within orthopaedics and medicine. Publicly available sources were used to compile institutional, gender, H-index, citation number, and subspecialty data on endowed professors; statistical comparisons were calculated. Results Within the top 100 orthopaedic academic departments, 4674 faculty were identified. Seven hundred and thirty-three (15.68%) were identified as women, 3941 as men (84.32%). One hundred and ninety-four held endowed professorships; 13 were awarded to women (6.7%), and 185 (95.3%) were awarded to men, with a significant odds ratio (OR) of 2.95, favoring men. For MSK researchers, the OR increases to 11.4. Arthroplasty and sports had the highest numbers of endowments. Significant differences in H-index, publications, and graduation year were identified between men and women for top MSK researchers and orthopaedic-trained surgeons; however, these differences disappeared when considering heterogenous orthopaedic departments that included medicine subspecialties, plastic surgery, hand surgery, and neurosurgery. Additional gender differences were observed in endowment names, with awards commemorating 51.5% men, 7.2% women, and 34% families or groups. Conclusion Gender inequities at the endowment level are substantial, and there are very few women in musculoskeletal medicine to achieve endowments. Differences in H-index, publications, and graduation year between men and women MSK researchers and orthopaedic-trained surgeons, but not combined orthopaedic, PM&R, and medical subspecialty departments, suggest unique challenges in orthopaedic surgery environments and histories that may contribute to endowment disparity. Gender was not found to be associated with funding bias for top-performing musculoskeletal researchers.

Defining Endogenous Mitochondrial Transfer in Muscle After Rotator Cuff Injury

BACKGROUND

Rotator cuff muscle degeneration leads to poor clinical outcomes for patients with rotator cuff tears. Fibroadipogenic progenitors (FAPs) are resident muscle stem cells with the ability to differentiate into fibroblasts as well as white and beige adipose tissue. Induction of the beige adipose phenotype in FAPs has been shown to improve muscle quality after rotator cuff tears, but the mechanisms of how FAPs exert their beneficial effects have not been fully elucidated.

PURPOSE

To study the horizontal transfer of mitochondria from FAPs to myogenic cells and examine the effects of β-agonism on this novel process.

STUDY DESIGN

Controlled laboratory study.

METHODS

In mice that had undergone a massive rotator cuff tear, single-cell RNA sequencing was performed on isolated FAPs for genes associated with mitochondrial biogenesis and transfer. Murine FAPs were isolated by fluorescence-activated cell sorting and treated with a β-agonist versus control. FAPs were stained with mitochondrial dyes and cocultured with recipient C2C12 myoblasts, and the rate of transfer was measured after 24 hours by flow cytometry. PdgfraCreERT/MitoTag mice were generated to study the effects of a rotator cuff injury on mitochondrial transfer. PdgfraCreERT/tdTomato mice were likewise generated to perform lineage tracing of PDGFRA+ cells in this injury model. Both populations of transgenic mice underwent tendon transection and denervation surgery, and MitoTag-labeled mitochondria from Pdgfra+ FAPs were visualized by fluorescent microscopy, spinning disk confocal microscopy, and 2-photon microscopy; overall mitochondrial quantity was compared between mice treated with β-agonists and dimethyl sulfoxide.

RESULTS

Single-cell RNA sequencing in mice that underwent rotator cuff tear demonstrated an association between transcriptional markers of adipogenic differentiation and genes associated with mitochondrial biogenesis. In vitro cocultures of murine FAPs with C2C12 cells revealed that treatment of cells with a β-agonist increased mitochondrial transfer compared to control conditions (17.8% ± 9.9% to 99.6% ± 0.13% P < .0001). Rotator cuff injury in PdgfraCreERT/MitoTag mice resulted in a robust increase in MitoTag signal in adjacent myofibers compared with uninjured mice. No accumulation of tdTomato signal from PDGFRA+ cells was seen in injured fibers at 6 weeks after injury, suggesting that FAPs do not fuse with injured muscle fibers but rather contribute their mitochondria.

CONCLUSION

The authors have described a novel process of endogenous mitochondrial transfer that can occur within the injured rotator cuff between FAPs and myogenic cells. This process may be leveraged therapeutically with β-agonist treatment and represents an exciting target for improving translational therapies available for rotator cuff muscle degeneration.

CLINICAL RELEVANCE

Promoting endogenous mitochondrial transfer may represent a novel translational strategy to address muscle degeneration after rotator cuff tears.

Distinct human stem cell subpopulations drive adipogenesis and fibrosis in musculoskeletal injury

Fibroadipogenic progenitors (FAPs) maintain healthy skeletal muscle in homeostasis but drive muscle degeneration in chronic injuries by promoting adipogenesis and fibrosis. To uncover how these stem cells switch from a pro-regenerative to pro-degenerative role we perform single-cell mRNA sequencing of human FAPs from healthy and injured human muscles across a spectrum of injury, focusing on rotator cuff tears. We identify multiple subpopulations with progenitor, adipogenic, or fibrogenic gene signatures. We utilize full spectrum flow cytometry to identify distinct FAP subpopulations based on highly multiplexed protein expression. Injury severity increases adipogenic commitment of FAP subpopulations and is driven by the downregulation of DLK1. Treatment of FAPs both in vitro and in vivo with DLK1 reduces adipogenesis and fatty infiltration, suggesting that during injury, reduced DLK1 within a subpopulation of FAPs may drive degeneration. This work highlights how stem cells perform varied functions depending on tissue context, by dynamically regulating subpopulation fate commitment, which can be targeted improve patient outcomes after injury.

Total shoulder arthroplasty in patients with dementia or mild cognitive impairment

Background

Anatomic total shoulder arthroplasty (ATSA) and reverse total shoulder arthroplasty (RTSA) reliably alleviate pain and restore shoulder function for a variety of indications. However, these procedures are not well-studied in patients with neurocognitive impairment. Therefore, the purpose of this study was to investigate whether patients with dementia or mild cognitive impairment (MCI) have increased odds of surgical or medical complications following arthroplasty.

Methods

The PearlDiver database was queried from 2010 through October 2021 to identify a cohort of patients who underwent either ATSA or RTSA and had a minimum 2-year follow-up. Current Procedural Terminology and International Classification of Diseases codes were used to stratify this cohort into three groups: (1) patients with dementia, (2) patients with MCI, and (3) patients with neither condition. Surgical and medical complication rates were compared among these three groups.

Results

The overall prevalence of neurocognitive impairment among patients undergoing total shoulder arthroplasty was 3.0% in a cohort of 92,022 patients. Patients with dementia had increased odds of sustaining a periprosthetic humerus fracture (odds ratio [OR] = 1.46, P < .001), developing prosthesis instability (OR = 1.72, P < .001), and undergoing revision arthroplasty (OR = 1.55, P = .003) after RTSA compared to patients with normal cognition. ATSA patients with dementia did not have an elevated risk of surgical complications or revision. Conversely, RTSA patients with MCI did not have an elevated risk of complications or revision, although ATSA patients with MCI had greater odds of prosthesis instability (OR = 2.51, P = .008). Additionally, patients with neurocognitive impairment had elevated odds of medical complications compared to patients with normal cognition, including acute myocardial infarction and cerebrovascular accident.

Conclusion

Compared to patients with normal cognition, RTSA patients with preoperative dementia and ATSA patients with preoperative MCI are at increased risk for surgical complications. Moreover, both ATSA and RTSA patients with either preoperative MCI or dementia are at increased risk for medical complications. As the mean age in the U.S. continues to rise, special attention should be directed towards patients with neurocognitive impairment to minimize postoperative complications aftertotal shoulder arthroplasty, and the risks of this surgery more carefully discussed with patients and their families and caretakers.

Incidence, risk factors, and complications of acromial stress fractures after reverse total shoulder arthroplasty

BACKGROUND

An acromial stress fracture (ASF) is an uncommon complication after reverse total shoulder arthroplasty (RTSA) that can have severe clinical consequences on shoulder function. Although patient-specific factors have been identified to influence the risk of ASF, it is unclear whether modifying these factors can minimize risk. Moreover, there is limited information on the treatment outcomes of these fractures. Therefore, the purpose of this study was to determine modifiable risk factors for ASFs and the complication and revision rates of conservatively and operatively managed ASFs.

METHODS

The PearlDiver database was queried to identify a cohort of patients who underwent RTSA with minimum 2-year follow-up. Current Procedural Terminology and International Classification of Diseases codes were used to compare the demographic characteristics, comorbidities, and medication use of patients with and without ASFs. Surgical complication and revision rates were compared between operatively and conservatively treated fractures.

RESULTS

The overall incidence of ASFs was 1.4%. Patient-specific factors that were independently associated with the occurrence of an ASF included osteoporosis, rheumatologic disease, shoulder corticosteroid injection within 3 months before surgery, and chronic oral corticosteroid use. Among patients with osteoporosis, the initiation of physical therapy within 6 weeks after surgery also increased the risk of ASF. Patients who underwent surgical treatment of ASFs had a revision arthroplasty rate of 7.0% compared to a rate of 3.2% among those with conservatively managed fractures.

CONCLUSION

ASFs are infrequent complications that can occur after RTSA. Preoperative factors that affect the quality of bone independently increase the fracture risk. Moreover, this risk can be minimized by avoiding shoulder corticosteroid injections 3 months before surgery and delaying physical therapy exercises among patients with osteoporosis. Surgical fixation of these fractures should be reserved for instances when conservative management has failed given high rates of infection, instability, and revision shoulder arthroplasty.

Periarticular injection in addition to interscalene nerve block can decrease opioid consumption and pain following total shoulder arthroplasty: a comparison cohort study

BACKGROUND

Interscalene nerve block (INB) is an effective technique to provide postoperative analgesia for total shoulder arthroplasty (TSA). However, the analgesic effects of the block typically resolve between 8 and 24 hours postadministration, which results in rebound pain and subsequent increased opioid use. The objective of this study was to address this issue by determining how adding an intraoperative periarticular injection (PAI) in combination with INB affects acute postoperative opioid consumption and pain scores in patients undergoing TSA. We hypothesized that compared with INB alone, INB + PAI will significantly reduce opioid consumption and pain scores for the first 24 hours postsurgery.

METHODS

We reviewed 130 consecutive patients who underwent elective primary TSA at a single tertiary institution. The first 65 patients were treated with INB alone, followed by 65 patients treated with INB + PAI. The INB used was 15-20 mL of 0.5% ropivacaine. The PAI used was 50 mL of a combination of ropivacaine (123 mg), epinephrine (0.25 mg), clonidine (40 μg), and ketorolac (15 mg). The PAI was injected using a standardized protocol: 10 mL into the subcutaneous tissues prior to incision, 15 mL into the supraspinatus fossa, 15 mL at the base of the coracoid process, and 10 mL into the deltoid and pectoralis muscles-a protocol analogous with a previously described technique. For all patients, a standardized postoperative oral pain medication protocol was used. The primary outcome was acute postoperative opioid consumption represented by morphine equivalent units (MEUs), whereas the secondary outcome was visual analog scale (VAS) pain scores over the first 24 hours postsurgery, operative time, length of stay, and acute perioperative complications.

RESULTS

No significant differences in demographics existed between patients who received INB alone vs. INB + PAI. Patients who received INB + PAI had a significantly lower 24-hour postoperative opioid consumption compared to the INB alone group (38.6 ± 30.5 MEU vs. 60.5 ± 37.3 MEU, P < .001). Additionally, VAS pain scores for the first 24 hours postsurgery in the INB + PAI group were significantly lower compared to those for the INB alone group (2.9 ± 1.5 vs. 4.3 ± 1.6, P ≤ .001). No differences existed between groups regarding operative time, length of inpatient stay, and acute perioperative complications.

CONCLUSION

Patients undergoing TSA with INB + PAI demonstrated significantly decreased 24-hour postoperative total opioid consumption and 24-hour postoperative pain scores compared to the group treated with INB alone. No increase in acute perioperative complications related to PAI was observed. Thus, compared to an INB, the addition of an intraoperative periarticular cocktail injection appears to be a safe and effective method to reduce acute postoperative pain following TSA.

Algorithmic assessment of shoulder function using smartphone video capture and machine learning

Tears within the stabilizing muscles of the shoulder, known as the rotator cuff (RC), are the most common cause of shoulder pain-often presenting in older patients and requiring expensive advanced imaging for diagnosis. Despite the high prevalence of RC tears within the elderly population, there is no previously published work examining shoulder kinematics using markerless motion capture in the context of shoulder injury. Here we show that a simple string pulling behavior task, where subjects pull a string using hand-over-hand motions, provides a reliable readout of shoulder mobility across animals and humans. We find that both mice and humans with RC tears exhibit decreased movement amplitude, prolonged movement time, and quantitative changes in waveform shape during string pulling task performance. In rodents, we further note the degradation of low dimensional, temporally coordinated movements after injury. Furthermore, a logistic regression model built on our biomarker ensemble succeeds in classifying human patients as having a RC tear with > 90% accuracy. Our results demonstrate how a combined framework bridging animal models, motion capture, convolutional neural networks, and algorithmic assessment of movement quality enables future research into the development of smartphone-based, at-home diagnostic tests for shoulder injury.

Polarized macrophages regulate fibro/adipogenic progenitor (FAP) adipogenesis through exosomes

BACKGROUND

Macrophage polarization has been observed in the process of muscle injuries including rotator cuff (RC) muscle atrophy and fatty infiltration after large tendon tears. In our previous study, we showed that fibrogenesis and white adipogenesis of muscle residential fibro/adipogenic progenitors (FAPs) cause fibrosis and fatty infiltration and that brown/beige adipogenesis of FAPs promotes rotator cuff muscle regeneration. However, how polarized macrophages and their exosomes regulate FAP differentiation remains unknown.

METHODS

We cultured FAPs with M0, M1, and M2 macrophages or 2 × 109 exosomes derived from M0, M1 and M2 with and without GW4869, an exosome inhibitor. In vivo, M0, M1, and M2 macrophages were transplanted or purified macrophage exosomes (M0, M1, M2) were injected into supraspinatus muscle (SS) after massive tendon tears in mice (n = 6). SS were harvested at six weeks after surgery to evaluate the level of muscle atrophy and fatty infiltration.

RESULTS

Our results showed that M2 rather than M0 or M1 macrophages stimulates brown/beige fat differentiation of FAPs. However, the effect of GW4869, the exosome inhibitor, diminished this effect. M2 exosomes also promoted FAP Beige differentiation in vitro. The transplantation of M2 macrophages reduced supraspinatus muscle atrophy and fatty infiltration. In vivo injections of M2 exosomes significantly reduced muscle atrophy and fatty infiltration in supraspinatus muscle.

CONCLUSION

Results from our study demonstrated that polarized macrophages directly regulated FAP differentiation through their exosomes and M2 macrophage-derived exosomes may serve as a novel treatment option for RC muscle atrophy and fatty infiltration.

Factors Associated With Humeral Avulsion of Glenohumeral Ligament Lesions in Patients With Anterior Shoulder Instability: An Analysis of the MOON Shoulder Instability Cohort

Background

Humeral avulsion of the glenohumeral ligament (HAGL) lesions are an uncommon cause of anterior glenohumeral instability and may occur in isolation or combination with other pathologies. As HAGL lesions are difficult to detect via magnetic resonance imaging (MRI) and arthroscopy, they can remain unrecognized and result in continued glenohumeral instability.

Purpose

To compare patients with anterior shoulder instability from a large multicenter cohort with and without a diagnosis of a HAGL lesion and identify preoperative physical examination findings, patient-reported outcomes, imaging findings, and surgical management trends associated with HAGL lesions.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Patients with anterior glenohumeral instability who underwent surgical management between 2012 and 2020 at 11 orthopaedic centers were enrolled. Patients with HAGL lesions identified intraoperatively were compared with patients without HAGL lesions. Preoperative characteristics, physical examinations, imaging findings, intraoperative findings, and surgical procedures were collected. The Student t test, Kruskal-Wallis H test, Fisher exact test, and chi-square test were used to compare groups.

Results

A total of 21 HAGL lesions were identified in 915 (2.3%) patients; approximately one-third (28.6%) of all lesions were visualized intraoperatively but not identified on preoperative MRI. Baseline characteristics did not differ between study cohorts. Compared with non-HAGL patients, HAGL patients were less likely to have a Hill-Sachs lesion (54.7% vs 28.6%; P = .03) or an anterior labral tear (87.2% vs 66.7%; P = .01) on preoperative MRI and demonstrated increased external rotation when their affected arm was positioned at 90° of abduction (85° vs 90°; P = .03). Additionally, HAGL lesions were independently associated with an increased risk of undergoing an open stabilization surgery (odds ratio, 74.6 [95% CI, 25.2-221.1]; P < .001).

Conclusion

Approximately one-third of HAGL lesions were missed on preoperative MRI. HAGL patients were less likely to exhibit preoperative imaging findings associated with anterior shoulder instability, such as Hill-Sachs lesions or anterior labral pathology. These patients underwent open procedures more frequently than patients without HAGL lesions.

Development and Validation of a Short-Form Version of the Western Ontario Shoulder Instability Scale (Short-WOSI)

BACKGROUND

Patient-reported outcome measures (PROMs) have transitioned from primarily being used as research instruments to becoming increasingly used in the clinical setting to assess recovery and inform shared decision-making. However, there is a need to develop validated short-form PROM instruments to decrease patient burden and ease incorporation into clinical practice.

PURPOSE

To assess the validity and responsiveness of a shortened version of the Western Ontario Shoulder Instability Index (Short-WOSI) when compared with the full WOSI and other shoulder-related PROM instruments.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

This study was a secondary analysis of data collected as part of an institutional review board-approved, multicenter cohort of 1160 patients undergoing surgical stabilization for shoulder instability. The following PROMs were captured preoperatively and 2 years after surgery: WOSI, American Shoulder and Elbow Surgeons (ASES) score, the Single Assessment Numeric Evaluation (SANE), and 36-Item Health Survey (RAND-36). The cohort was split into 2 data sets: a training set to be used in the development of the Short-WOSI (n = 580) and a test set to be used to assess the validity and responsiveness of the Short-WOSI relative to the full WOSI, ASES, SANE, and RAND-36.

RESULTS

The Short-WOSI demonstrated excellent internal consistency before surgery (Cronbach α = .83) and excellent internal consistency at the 2-year follow-up (Cronbach α = .93). The baseline, 2-year, and pre- to postoperative changes in Short-WOSI and WOSI were closely correlated (r > 0.90), with both demonstrating large effect sizes (Short-WOSI = 1.92, WOSI = 1.81). Neither the Short-WOSI nor the WOSI correlated well with the other PROM instruments before (r = 0.21-0.33) or after (r = 0.25-0.38) surgery. The Short-WOSI, WOSI, and SANE scores were more responsive than ASES and RAND-36 scores.

CONCLUSION

The 7-item Short-WOSI demonstrated excellent internal consistency and a lack of floor or ceiling effects. The Short-WOSI demonstrated excellent cross-sectional and longitudinal construct validity and was similarly responsive over time as the full WOSI. Neither the Short-WOSI nor WOSI correlated with more general shoulder PROMs, underscoring the advantage of using instability-specific instruments for this population.

Association of Medial Meniscus Root Tears and Nonroot Tears With Worsening of Radiographic Knee Osteoarthritis

Background

Medial meniscus root tears (RTs) are associated with the development and worsening of knee osteoarthritis (OA), but little is known about their progression when compared with meniscal tears that spare the root (nonroot tears; NRTs).

Purpose

To compare radiographic worsening of OA in knees with RTs versus NRTs and to identify factors associated with radiographic worsening of OA in knees with RTs.

Study Design

Cohort study; Level of evidence, 3.

Methods

Using the Osteoarthritis Initiative database, we included knees with medial meniscus RTs and NRTs present at the baseline visit (baseline tears) and new RTs and NRTs observed at 12- to 48-month annual follow-up visits (incident tears). Worsening of radiographic OA was defined for baseline tears as an increase in Kellgren-Lawrence grade (KLG) during the subsequent 12 months of follow-up; for incident tears, worsening was defined as either concurrent (increase in KLG over the 12 months preceding tear appearance on magnetic resonance imaging) or subsequent (increase in KLG during the 12 months after tear appearance). Odds ratios (ORs), adjusted for covariates, were calculated for the association of worsening by type of tear.

Results

Included were 39 knees with baseline RTs, 633 knees with baseline NRTs, 33 knees with incident RTs, and 234 knees with incident NRTs. Radiographic OA worsening subsequent to meniscal tear identification was no different for baseline RTs (15%) or baseline NRTs (14%; adjusted OR, 1.34; 95% CI, 0.52-3.47), nor did subsequent worsening differ for incident RTs (19%) versus incident NRTs (18%; adjusted OR, 0.52; 95% CI, 0.15-1.83). Concurrent radiographic OA worsening was seen at a significantly higher rate for incident RTs (64%) versus incident NRTs (21%; adjusted OR, 3.00; 95% CI, 1.21-7.47). Incident RTs in knees without radiographic OA (KLG 0-1) before the tear had a high rate of worsening (94%, n = 16) and were more likely to worsen than those in knees with radiographic OA (KLG ≥2) present before the tear.

Conclusion

Compared with NRTs, incident RTs were associated with a significantly increased risk of worsening radiographic OA over a 12-month period concurrent with the appearance of the tear. Incident RTs in knees without radiographic OA at baseline had a high rate of worsening.

Leukocyte-Poor Platelet-Rich Plasma Injections Improve Cartilage T1ρ and T2 and Patient-Reported Outcomes in Mild-to-Moderate Knee Osteoarthritis

Purpose

To use T1ρ and T2 magnetic resonance imaging to evaluate the effect of leukocyte-poor platelet-rich plasma (LP-PRP) injections on knee cartilage health and to correlate structural changes with patient-reported outcome measurements.

Methods

Ten patients with symptomatic unilateral mild-to-moderate knee osteoarthritis (Kellgren-Lawrence Grade 1-2) underwent T1ρ and T2 magnetic resonance imaging of both the symptomatic and contralateral knee before injection and 6 months after injection with LP-PRP. Patient-reported outcome questionnaires (Knee Osteoarthritis Outcome Score and International Knee Documentation Committee) that evaluate the domains of pain, symptoms, activities of daily living, sports function, and quality of life were completed at baseline, 3 months, 6 months, and 12 months after injection. T1ρ and T2 relaxation times, which are correlated with the proteoglycan and collagen concentration of cartilage, were measured in compartments with and without chondral lesions.

Results

Ten patients were prospectively enrolled (9 female, 1 male) with a mean age of 52.9 years (range, 42-68) years and mean body mass index of 23.2 ± 1.9. Significant increases in Knee Osteoarthritis Outcome Score for all subscales and International Knee Documentation Committee scores were observed 3 months after injection and the improvements were sustained at 12 months. T1ρ and T2 values of compartments with chondral lesions were observed to significantly decrease by 6.0% (P = .036) and 7.1% (P = .017) 6 months after LP-PRP injection, respectively. No significant associations between T1ρ and T2 relaxation times and improvement in patient-reported outcomes were observed.

Conclusions

Patients undergoing LP-PRP injections for the treatment of mild-to-moderate knee osteoarthritis had increased proteoglycan and collagen deposition in the cartilage of affected compartments by 6 months after injection. Patient-reported outcomes scores improved 3 months after injection and were sustained through 1 year after injection, but these improvements were not associated with the changes in proteoglycan and collagen deposition in knee cartilage.

Level of Evidence

Level II, prospective cohort study.

Preventing and Treating Infection in Reverse Total Shoulder Arthroplasty

PURPOSE OF REVIEW

Periprosthetic infection after shoulder arthroplasty is relatively uncommon though associated with severe long-term morbidity when encountered. The purpose of the review is to summarize the recent literature regarding the definition, clinical evaluation, prevention, and management of prosthetic joint infection after reverse shoulder arthroplasty.

RECENT FINDINGS

The landmark report generated at the 2018 International Consensus Meeting on Musculoskeletal Infection has provided a framework for diagnosis, prevention, and management of periprosthetic infections after shoulder arthroplasty. Shoulder specific literature with validated interventions to reduce prosthetic joint infection is limited; however existing literature from retrospective studies and from total hip and knee arthroplasty allows us to make relative guidelines. One and two-stage revisions seem to demonstrate similar outcomes; however, no controlled comparative studies exist limiting the ability to make definitive recommendations between the two options. We report on recent literature regarding the current diagnostic, preventative, and treatment options for periprosthetic infection after shoulder arthroplasty. Much of the literature does not distinguish between anatomic and reverse shoulder arthroplasty, and further high-level shoulder specific studies are needed to answer questions generated from this review.

Outcomes of anatomic and reverse total shoulder arthroplasty in patients over the age of 70: a systematic review

Background

Both anatomic total shoulder arthroplasty (ATSA) and reverse total shoulder arthroplasty (RTSA) reliably improve pain and function for a variety of indications. However, there remain concerns about these procedures among elderly patients due to their general health, the potential for lesser functional gain, and the possible need for revision at an even older age. The purpose of this review is to compare the clinical outcomes, radiographic outcomes, and complications of ATSA and RTSA among patients older than 70 years.

Methods

A systematic review was performed using searches of PubMed, Embase, and Cochrane databases. The inclusion criteria were studies with patients older than 70 years who were treated with a primary ATSA or RTSA and clinical results reported at a minimum of 2 years. All indications for primary RTSA except for tumor were included. Outcomes of interest included patient-reported outcomes (PROs), range of motion, patient satisfaction, radiographic changes, complication and revision rates, and implant survival.

Results

A total of 24 studies met the inclusion criteria. At a mean follow-up of 3.4 years for ATSA and 3.1 years for RTSA, there were significant improvements in pain, range of motion, and PROs for both prostheses. Patients who underwent ATSA generally had better motion and functional outcomes compared to those who underwent RTSA, though these comparisons were made across different indications for arthroplasty. The satisfaction rate was 90.9% after ATSA and 90.8% after RTSA. Furthermore, 10.2% of ATSA patients and 9.9% of RTSA patients experienced a surgical complication, whereas 2.3% of ATSA and 2.2% of RTSA patients underwent a revision. Secondary rotator cuff tear was the most common complication after ATSA, occurring in 3.7% of patients, but only 1.1% of patients required revision surgery. Both ATSA and RTSA implant survivorship was reported to range from 93.1% to 98.9% at 5- and 8-year follow-up, respectively. Patient mortality was estimated to be 19.3% with a mean time to death of 6.1 years.

Conclusions

Elderly patients with primary osteoarthritis and an intact rotator cuff can have predictable pain relief, restoration of functional range of motion, and significant improvement in PROs after ATSA with low complication rates. Secondary rotator cuff failure and revision arthroplasty occur infrequently at early to mid-term follow-up. Although elderly patients who underwent ATSA generally had better functional outcomes compared to those who underwent RTSA for differing indications, patient satisfaction after both procedures were similar.

A Tool for Low-Cost, Quantitative Assessment of Shoulder Function Using Machine Learning

Tears within the stabilizing muscles of the shoulder, known as the rotator cuff (RC), are the most common cause of shoulder pain-often presenting in older patients and requiring expensive, advanced imaging for diagnosis1-4. Despite the high prevalence of RC tears within the elderly population, there are no accessible and low-cost methods to assess shoulder function which can eschew the barrier of an in-person physical exam or imaging study. Here we show that a simple string pulling behavior task, where subjects pull a string using hand-over-hand motions, provides a reliable readout of shoulder health across animals and humans. We find that both mice and humans with RC tears exhibit decreased movement amplitude, prolonged movement time, and quantitative changes in waveform shape during string pulling task performance. In rodents, we further note the degradation of low dimensional, temporally coordinated movements after injury. Furthermore, a predictive model built on our biomarker ensemble succeeds in classifying human patients as having a RC tear with >90% accuracy. Our results demonstrate how a combined framework bridging task kinematics, machine learning, and algorithmic assessment of movement quality enables future development of smartphone-based, at-home diagnostic tests for shoulder injury.

Incidence of Venous Thromboembolism After Hip Arthroscopy Is Low With or Without Prophylaxis but Risk Factors Include Oral Contraceptive Use, Obesity, and Malignancy

PURPOSE

To determine the incidence of and risk factors for symptomatic venous thromboembolism (VTE) after hip arthroscopy (HA) and thromboprophylaxis prescription utilization for this procedure.

METHODS

The PearlDiver Mariner database was queried using Current Procedural Terminology codes to identify adult patients (aged ≥ 18 years) who underwent HA between 2010 and 2020. Patient demographic information, including age, oral contraceptive use, and medical comorbidities, as well as perioperative thromboprophylaxis utilization, was recorded using International Classification of Diseases codes and National Drug Codes. The incidence of postoperative VTE within 90 days was determined. Multivariate logistic regression was used to identify predictors of perioperative thromboprophylaxis utilization and risk factors for VTE.

RESULTS

The queried records identified 60,181 patients who met the inclusion criteria. Of these patients, 367 (0.6%) experienced VTE, including deep venous thrombosis (0.5%) and/or pulmonary embolism (0.2%). Approximately 2.1% of patients used thromboprophylaxis, including aspirin (1.1%), low-molecular-weight heparin (0.9%), and oral factor Xa inhibitors (0.1%). Oral contraceptive pill use (adjusted odds ratio [aOR], 2.16; 95% confidence interval [CI], 1.34-3.46), obesity (aOR, 1.37; 95% CI, 1.05-1.79), and a history of malignancy (aOR, 1.69; 95% CI, 1.12-2.54) were associated with increased odds of experiencing VTE. Perioperative thromboprophylaxis (aOR, 0.52; 95% CI, 0.19-1.39) was not significantly associated with decreased odds of experiencing VTE. However, obesity (aOR, 1.17; 95% CI, 1.00-1.38) and hypertension (aOR, 1.17; 95% CI, 1.02-1.36) were associated with increased odds of thromboprophylaxis prescription utilization.

CONCLUSIONS

Although the overall risk of symptomatic VTE after HA remains low, oral contraceptive use, obesity, and a history of malignancy are associated with increased odds of thromboembolic events within 90 days. Routine thromboprophylaxis after HA may not be indicated in all patients but can be considered based on patient-specific risk factors.

LEVEL OF EVIDENCE

Level III, retrospective prognostic comparative trial.

Predictors of Bone Loss in Anterior Glenohumeral Instability

BACKGROUND

Anterior shoulder instability can result in bone loss of both the anterior glenoid and the posterior humerus. Bone loss has been shown to lead to increased failure postoperatively and may necessitate more complex surgical procedures, resulting in worse clinical outcomes and posttraumatic arthritis.

HYPOTHESIS/PURPOSE

The purpose of this study was to investigate predictors of glenoid and humeral head bone loss in patients undergoing surgery for anterior shoulder instability. It was hypothesized that male sex, contact sport participation, traumatic dislocation, and higher number of instability events would be associated with greater bone loss.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 892 patients with anterior shoulder instability were prospectively enrolled in the Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Instability cohort. The presence and amount of anterior glenoid bone loss and accompanying Hill-Sachs lesions were quantified. Descriptive information and injury history were used to construct proportional odds models for the presence of any bone defect, for defects >10% of the anterior glenoid or humeral head, and for combined bony defects.

RESULTS

Anterior glenoid bone loss and Hill-Sachs lesions were present in 185 (20.7%) and 470 (52.7%) patients, respectively. Having an increased number of dislocations was associated with bone loss in all models. Increasing age, male sex, and non-White race were associated with anterior glenoid bone defects and Hill-Sachs lesions. Contact sport participation was associated with anterior glenoid bone loss, and Shoulder Actitvity Scale with glenoid bone loss >10%. A positive apprehension test was associated with Hill-Sachs lesions. Combined lesions were present in 19.4% of patients, and for every additional shoulder dislocation, the odds of having a combined lesion was 95% higher.

CONCLUSION

An increasing number of preoperative shoulder dislocations is the factor most strongly associated with glenoid bone loss, Hill-Sachs lesions, and combined lesions. Early surgical stabilization before recurrence of instability may be the most effective method for preventing progression to clinically significant bone loss. Patients should be made aware of the expected course of shoulder instability, especially in athletes at high risk for recurrence and osseous defects, which may complicate care and worsen outcomes.

REGISTRATION

NCT02075775 (ClinicalTrials.gov identifier).

Gender and Racial Diversity Among the Head Medical and Athletic Training Staff of Women's Professional Sports Leagues

Background

Despite increased awareness for promoting diversity, orthopaedics remains one of the least diverse specialties. Studying health care providers in women's professional sports provides a unique opportunity to analyze gender and racial diversity.

Hypotheses

There would be low female and minority representation across the various women's professional sports leagues. There would be an increased number of female head certified athletic trainers (ATCs) when compared with head team physicians (HTPs).

Study Design

Cross-sectional study.

Methods

We evaluated the perceived race and sex of designated HTPs and ATCs in the Women's National Basketball Association, National Women's Soccer League, and National Women's Hockey League. Type of doctorate degree, specialty, and years in practice were also collected. Kappa (κ) coefficient measurements were used to determine interobserver agreement on race. Categorical and continuous variables were analyzed using chi-square and t tests, respectively.

Results

There were significantly more female ATCs than female HTPs (74.1% vs 37.5%; P = .01). Minority representation between HTPs and ATCs was not significantly different (20.8% vs 40.7%; P = .13). Black HTPs (12.5%) and Black ATCs (22.2%) composed the largest proportion among the minority groups. There was high interobserver agreement of perceived race across HTPs (κ = 1.0) and ATCs (κ = 0.95).

Conclusion

Although there were more female ATCs than HTPs in women's professional sports leagues, both cohorts lack perceived racial diversity. These data suggest an opportunity for diversification in medical and training staff of women's professional sports.

Pre-existing Mental Health Diagnoses Are Associated With Higher Rates of Postoperative Complications, Readmissions, and Reoperations Following Arthroscopic Rotator Cuff Repair

PURPOSE

To investigate the association between preoperative mental health disorders and postoperative complications, readmissions, and ipsilateral revision procedures among patients undergoing arthroscopic rotator cuff repair (RCR).

METHODS

A retrospective cohort study from 2010 to 2020 was performed using the PearlDiver database. Current Procedural Terminology and International Classification of Diseases codes were used to compare patients with and without mental health disorders who underwent arthroscopic RCR. Mental health disorders evaluated in this study include depressive disorder, major depressive disorder, major depressive affective disorder, bipolar disorder, dysthymic disorder, adjustment disorder, separation anxiety disorder, and posttraumatic stress disorder. Patients were matched at a 1:1 ratio based on age, sex, Charlson Comorbidity Index, body mass index, and tobacco use. Rates of complications and subsequent surgeries were compared between patients with and without a preoperative diagnosis of a mental health disorder.

RESULTS

The 1-year preoperative prevalence of a mental health disorder from 2010 to 2020 was 14.6%. After 1:1 matching, patients with a mental health disorder who underwent arthroscopic RCR were nearly twice as likely to undergo a revision procedure (odds ratio 1.94, 95% confidence interval 1.76-2.14, P < .001) and more than twice as likely to experience conversion to shoulder arthroplasty (odds ratio 2.29, 95% confidence interval 1.88-2.80, P < .001) within 2 years of initial arthroscopy when compared with patients without a mental disorder. Patients with a mental disorder also experienced increased risk for 90-day readmission (1.9% vs 0%, P < .001) as well as multiple postoperative medical complications.

CONCLUSIONS

Patients with pre-existing mental health diagnoses experience increased rates of 90-day postoperative complications and readmissions following arthroscopic RCR. In addition, patients with mental health diagnoses are more likely to undergo revision repair and conversion to shoulder arthroplasty within 2 years of the index procedure.

LEVEL OF EVIDENCE

Level III.

Effect of obesity on short- and long-term complications of shoulder arthroplasty

BACKGROUND

The proportion of patients undergoing total shoulder arthroplasty (TSA) with obesity continues to grow every year in the United States. Although comorbid obesity is common among TSA patients, the relationship of obesity on medical and surgical complications remains debated. The goal of this study was to evaluate a national database for postoperative medical and surgical complications in patients undergoing TSA with comorbid obesity.

METHODS

Patients undergoing anatomic and reverse TSA were studied in the PearlDiver database. Current Procedural Terminology (CPT) and International Classification of Diseases (ICD) codes were used to compare patients with and without preoperative obesity who underwent TSA, and they were stratified based on body mass index (BMI) into nonobese, obese, morbidly obese, and superobese. A matched comparison was performed at a 1:1 ratio based on age, sex, diabetes, smoking, tobacco use, and Charlson Comorbidity Index.

RESULTS

From 2010 to 2020, a total of 113,634 patients undergoing anatomic or reverse TSA were identified in a national database. During this time, the percentage of TSA patients with obesity increased every year. Matched cohort analysis demonstrated higher odds of readmission, deep vein thrombosis and pulmonary embolism, superficial infection, and prosthetic joint infection at 90 days postoperatively in the obesity group. There were no increased odds of mechanical complications or revision surgery at 2 years in the obesity group when matched to nonobese patients with similar comorbidities.

CONCLUSION

The number of patients undergoing TSA with obesity is rising. Medical complications and infection after TSA are greater in obese patients even when matching for medical comorbidities, age, and sex, and rates of complication increase as BMI increases. Obesity is not an independent risk factor for mechanical surgical complications and revision surgery, and the relatively higher rates are likely due to an increased burden of other comorbidities. Surgeons should counsel obese patients appropriately regarding their perioperative risk of medical complication, but they should not expect higher rates of mechanical complication or revision surgery at 2-year follow-up when compared to a matched control group with similar comorbidities.

Relationship Between Preoperative Shoulder Osteoarthritis Severity Score and Postoperative PROMIS-UE Score After Rotator Cuff Repair

Background

Mild to moderate glenohumeral joint osteoarthritis is a common finding among patients who are evaluated for rotator cuff tears. However, the impact of preoperative shoulder joint degeneration on patient-reported outcomes after rotator cuff repair (RCR) is not well-established.

Purpose

To apply the magnetic resonance imaging (MRI)-based Shoulder Osteoarthritis Severity (SOAS) score to the evaluation of patients undergoing RCR and determine the relationship between preoperative shoulder pathology present on MRI and postoperative Patient-Reported Outcomes Measurement Information System-Upper Extremity (PROMIS-UE) scores.

Study Design

Case-control study; Level of evidence, 3.

Methods

Seventy-one MRI scans corresponding to 71 patients were analyzed by 2 independent reviewers and scored using the SOAS criteria. Intraclass correlation coefficients were calculated for total SOAS score as well as for each subscore. Spearman correlations were calculated between averaged SOAS scores, patient characteristics, and PROMIS-UE scores. Linear regression analysis was performed between the independent variables of patient age, sex, body mass index, and significant SOAS score components determined by univariate analysis with the dependent variable of PROMIS-UE score. Significance was defined as P < .05 for univariate analyses and < .0125 for multivariate analyses using the Bonferroni correction.

Results

The mean PROMIS-UE score of this cohort was 51.5 ± 7.4, while the mean total SOAS score was 21.5 ± 8.4. There was a negative correlation between total SOAS score and postoperative PROMIS-UE score (r = -0.24; P = .040). Both cartilage wear (r = -0.33; P = .0045) and acromioclavicular joint degeneration (r = -0.24; P = .048) individually demonstrated negative correlations with PROMIS-UE score. When a multivariate linear regression with Bonferroni correction was applied to the significant variables identified in univariate analysis along with patient characteristics, none were independently correlated with PROMIS-UE score.

Conclusion

In this cohort of patients undergoing RCR, increasing preoperative total SOAS score was predictive of lower postoperative PROMIS-UE scores. SOAS subscores with the strongest negative correlations with PROMIS-UE scores included cartilage wear and acromioclavicular joint degeneration. The cartilage subscore was negatively correlated with PROMIS-UE scores independent of patient factors in multivariate analysis.

#OrthoTwitter: Relationship Between Author Twitter Utilization and Academic Impact in Orthopaedic Surgery

Background #OrthoTwitter has evolved to disseminate findings and engage the public. However, the academic impact of Twitter utilization in orthopaedic surgery is unknown. Questions/purposes The purpose of the study was to evaluate relationships between the author and manuscript Twitter activity and citations. Methods Manuscripts in 17 orthopaedic journals from 2018 were identified. Citations, online mentions, impact factors, and subspecialties were obtained. H-index and Twitter account details for authors were obtained for a subset of manuscripts. Relationships between Twitter activity and citations were evaluated. Results 2,473/4,224 (58.5%) manuscripts were mentioned on Twitter (n=29,958 mentions), with Twitter manuscripts cited more frequently (median 10 vs. 7, p<0.0001). Twitter mentions, impact factors, non-open-access status, and subspecialties were associated with citation counts. Articles mentioned in 10, 100, and 1,000 Tweets were observed to have a 1.1-fold, 1.7-fold, and 245-fold increase in citations. In author-level analyses, 156 (20.0%) first and 216 (27.7%) senior authors had Twitter accounts. Citation count was associated with increasing senior author H-index (β _est=0.13, p<0.05), Twitter mentions (β _est=0.0043, p<0.0001), impact factors (β _est=0.13, p<0.0001), and having a first (β _est=0.20, p<0.05) or senior author (β _est=0.17, p<0.05) on Twitter. Articles published in arthroplasty (β _est=0.49, p<0.05), general interest (β _est=0.55, p<0.01), sports (β _est=0.63, p<0.01), and non-open access journals (β _est=0.41, p<0.001) were cited more. H-index correlated with followers for first (rho=0.31, p<0.0001) and senior authors (rho=0.44, p<0.0001). Conclusion Author Twitter utilization is independently associated with manuscript citations. Authors should be aware of the potential association between social media utilization and traditional academic impact. Understanding the relationship between social media utilization and academic impact is necessary to effectively disseminate research.

Surgeon variation in glenoid bone reconstruction procedures for shoulder instability

BACKGROUND

Advances in the understanding and management of glenoid bone loss in shoulder instability have led to the development of alternative bony reconstruction techniques to the Latarjet using free bone grafts, but little is known about surgeon adoption of these procedures. This study sought to characterize surgeon variation in the use of glenoid bone reconstruction procedures for shoulder instability and ascertain reasons underlying procedure choice.

METHODS

A 9-question survey was created and distributed to 160 shoulder surgeons members of the PacWest Shoulder and Elbow Society, of whom 65 (41%) responded. The survey asked questions regarding fellowship training, years in practice, surgical volume, preferred methods of glenoid bone reconstruction, and reasons underlying treatment choice.

RESULTS

All surgeons completed a fellowship, with an equal number of sports medicine fellowship-trained (46%) and shoulder and elbow fellowship-trained (46%) physicians. The majority had been in practice for at least 6 years (6-10 years: 25%; >10 years: 59%). Most (78%) performed ≤10 glenoid bony reconstructions per year, and 66% indicated that bony procedures represented <10% of their total annual shoulder instability case volume. The open Latarjet was the preferred primary reconstruction method (69%), followed by open free bone block (FBB) (22%), arthroscopic FBB (8%), and arthroscopic Latarjet (1%). Distal tibia allograft (DTA) was the preferred graft (74%) when performing an FBB procedure, followed by iliac crest autograft (18%), and distal clavicle autograft (6%). The top 5 reasons for preferring Latarjet over FBB were the sling effect (57%), the autologous nature of the graft (37%), its robust clinical evidence (22%), low cost (17%), and availability (11%). The top 5 reasons for choosing an FBB procedure were less anatomic disruption (58%), lower complication rate (21%), restoration of articular cartilage interface (16%), graft versatility (11%), and technical ease (11%). Only 20% of surgeons indicated always performing a bony glenoid reconstruction procedure in the noncontact athlete with less than 20% glenoid bone loss. However, that percentage rose to 62% when considering a contact athlete with the same amount of bone loss.

CONCLUSIONS

Although open Latarjet continues to be the most popular glenoid bony primary reconstruction procedure in shoulder instability, nearly 30% of shoulder surgeons in the western United States have adopted FBB techniques as their preferred treatment modality--with DTA being the most frequently used graft. High-quality comparative clinical effectiveness research is needed to reduce decisional conflict and refine current evidence-based treatment algorithms.

The Role of Matrix Metalloproteinase-13 (MMP13) in TGFβ/BMP Pathway Regulation of Fibro-Adipogenic Progenitor (FAP) Differentiation

BACKGROUND/AIMS

Muscle fibrosis and fatty infiltration (FI) are common complications seen in various muscle disease states. Recent studies indicate that muscle residential fibro/adipogenic progenitors (FAPs) are the major cellular source for muscle fibrosis and FI. We previously showed that MMP13 knockout (KO) mice have significantly increased FI, suggesting an important role of MMP13 in muscle FI. However, how MMP13 affects the differentiation of FAPs remains unknown.

METHODS

In order to assess the role of MMP-13 on FAP differentiation, we isolated FAPs from wildtype C57BL/6 and MMP13 knock out mice with FACS using CD31-, CD45-, Integrin α7- and Sca-1+ markers. FAPs were cultured in 24 well plate after FACS.in standard media till 80% confluent and then switched to adipogenic medium. In order to study the role of TGFβ and BMP in their differentiation, FAPs from both wildtype and MMP13 KO mice were treated with TGFβ1 (5 ng/ml). For MMP13 inhibitor treatment, FAPs from wildtype mice were incubated in adipogenic medium containing 10 µM MMP13 inhibitor (or vehicle) for 2 weeks. Immunofluorescence and gene expression analysis were used to assess FAP adipogenic and fibrogenic differentiation. FAPs were stained with Perilipin A (FITC, adipogenesis marker) and αSMA (Red, fibroblast marker), and DAPI. Real time PCR was performed for gene expression evaluation. A two-tailed Anova was used for statistical comparisons between groups, with
p ≤ 0.05. Data are presented as mean ± standard deviation.

RESULTS

In this study, we isolated FAPs from wildtype C57BL/6 and MMP13 KO mice and evaluated their adipogenic and fibrogenic differentiation in vitro. MMP13 KO FAPs demonstrated enhanced adipogenesis but reduced fibrogenesis compared to wildtype FAPs. Treating wildtype FAPs with an MMP13 inhibitor simulated phenotypes seen in MMP13 KO FAPs. In order to assess the role of MMP13 on TGFβ/BMP signaling in regulating FAP differentiation, we treated wildtype and MMP13 KO FAPs with TGFβ1, BMP7, TGFβ inhibitor, and BMP inhibitor. TGFβ1 treatment significantly enhanced fibrogenesis, but inhibited adipogenesis of wildtype FAPs. However, treatment with BMP7 showed the opposite effect. Interestingly, the effect of TGFβ1/BMP7 was voided in MMP13 KO FAPs. Treating wildtype FAPs with MMP13 inhibitor also abolished the effect of TGFβ1/BMP7 in FAP differentiation.

CONCLUSION

Results from this study showed that TGFβ1 inhibits FAP adipogenesis but stimulates FAP fibrogenesis. BMP7 was shown to promote FAP adipogenesis but reduce its fibrogenesis. The role of the TGFβ/BMP signaling pathway regulating FAP differentiation was found to be MMP13 dependent. This study suggests that MMP13 is a critical downstream effector in TGFβ/BMP pathway which may serve as a new therapeutic target for muscle fibrosis and FI.

Delayed ACL reconstruction increases rates of concomitant procedures and risk of subsequent surgery

PURPOSE

To utilise a large cross-sectional database to analyse the effects of time duration between diagnosis of anterior cruciate ligament (ACL) tear and ACL reconstruction (ACLR) on concomitant procedures performed and subsequent surgery within 2 years.

METHODS

An analysis from 2015 to 2018 was performed using the Mariner PearlDiver Patient Records Database. Current Procedural Terminology (CPT), and International Classification of Diseases (ICD-10) codes identified patients with a diagnosis of ACL tear who underwent subsequent ACLR. Patients were stratified in biweekly and bimonthly increments based on the time duration between initial diagnosis of ACL tear and surgical treatment. Chi-squared analysis was used to compare categorical variables, and trend analysis was performed with Cochran-Armitage independence testing.

RESULTS

Of 11,867 patients who underwent ACLR, 76.1% underwent surgery within 2 months of injury diagnosis. Patients aged 10-19 were most likely to undergo surgery within 2 months of injury diagnosis (83.5%, P < 0.0001). As duration from injury diagnosis to ACLR increased from < 2 months to > 6 months, rates of concomitant meniscectomy increased from 9.1% to 20.5% (P < 0.0001). The overall 2-year subsequent surgery rate was 5.3%. The incidence of revision ACLR was highest for patients who underwent surgery > 6 months after diagnosis (P < 0.0001), whilst the incidence of ipsilateral lysis of adhesions and manipulation under anaesthesia (MUA) was highest for patients who underwent surgery < 2 months after diagnosis (P < 0.0001). ACLR at 6-8 weeks after diagnosis demonstrated the lowest risk for concomitant procedures as well as 2-year subsequent surgery.

CONCLUSION

The majority of patients undergo ACL reconstruction within 2 months of initial ACL tear diagnosis. Delayed surgery greater than 6 months after the diagnosis of an ACL rupture leads to increased need for concomitant meniscectomy as well as higher risk for revision ACLR within 2 years, but immediate surgery may increase risk for knee arthrofibrosis.

LEVEL OF EVIDENCE

IV.

A novel mouse model of hindlimb joint contracture with 3D-printed casts

Stiff joints formed after trauma, surgery or immobilization are frustrating for surgeons, therapists and patients alike. Unfortunately, the study of contracture is limited by available animal model systems, which focus on the utilization of larger mammals and joint trauma. Here we describe a novel mouse-based model system for the generation of joint contracture using 3D-printed clamshell casts. With this model system we are able to generate both reversible and irreversible contractures of the knee and ankle. Four- or 8-month-old female mice were casted for either 2 or 3 weeks before liberation. All groups formed measurable contractures of the knee and ankle. Younger mice immobilized for less time formed reversible contractures of the knee and ankle. We were able to generate irreversible contracture with either longer immobilization time or the utilization of older mice. The contracture formation translated into differences in gait, which were detectable using the DigiGait® analysis system. This novel model system provides a higher throughput, lower cost and more powerful tool in studying the molecular and cellular mechanisms considering the large existing pool of transgenic/knockout murine strains.

Complications after high tibial osteotomy and distal femoral osteotomy are associated with increasing medical comorbidities and tobacco use

PURPOSE

The purpose of this study was to assess complications, reoperations, and their risk factors at 90 days and 2 years after high tibial osteotomy (HTO) and distal femoral osteotomy (DFO) in a national cohort.

METHODS

The PearlDiver Mariner Dataset was queried using International Classification of Diseases (ICD) and Current Procedural Terminology (CPT) codes for HTO and DFO, complications, and subsequent surgery. Minimum follow-up was 2 years and complications were assessed at 90 days and 2 years. Hospital readmission in the first 90 days was also assessed. Univariate and multiple logistic regression were utilized to identify risk factors for complications and re-operation.

RESULTS

The 90-day and 2-year complication rates after HTO (n = 1780) were 11.6% and 31.7%, compared to 21.5% (p < 0.0001) and 41.5% (p = 0.0001) after DFO (n = 446). Infection was the most frequent early (90-day) complication for both HTO and DFO cohorts, while hardware problems were most common at 2 years. Increasing Elixhauser Comorbidity Index (ECI) was associated with increased odds of infection, readmission, and hardware-associated complications in both cohorts. Gender and tobacco use were also associated with various complications after HTO. At 2 years, 23.7% of HTO patients and 26.2% of DFO patients had undergone subsequent surgery. Hardware removal occurred in 16.4% of HTO and 18.4% of DFO patients (n.s.), while 4.5% of HTO and 5.2% of DFO patients underwent total knee arthroplasty (TKA) within 2 years (n.s.).

CONCLUSION

HTO and DFO have substantial complication rates in the short and mid term, with a higher rate of overall complications observed after DFO as compared to the HTO cohort. After both procedures, roughly one quarter of patients will undergo subsequent surgery within 2 years. Patients with tobacco use and numerous medical co-morbidities may not be optimal candidates due to increased complication rates. Elixhauser Comorbidity Index (ECI) may be an useful tool for risk assessment prior to surgery.

LEVEL OF EVIDENCE

Retrospective cohort study, III.

Perioperative Thromboprophylaxis Is Associated With Lower Risk of Venous Thromboembolism After Knee Arthroscopy

PURPOSE

To determine the rate of symptomatic venous thromboembolism (VTE) among patients undergoing arthroscopic knee procedures, risk factors associated with postoperative VTE, and current perioperative thromboprophylaxis prescription patterns associated with this population in the United States.

METHODS

Medical records for patients ≥18 years of age were queried from the Mariner database using Current Procedural Terminology codes for knee arthroscopy performed in the United States from 2010 to 2020 in this cross-sectional study. Patients who received thromboprophylaxis and those diagnosed with VTE, including deep-vein thrombosis or pulmonary embolism, within 90 days of surgery were identified using International Classification of Diseases and National Drug Codes. Two multivariable logistic regression models were used to identify VTE risk factors and likelihood of perioperative thromboprophylaxis. Covariates included procedure type, age, oral contraceptive pill (OCP) use, and medical comorbidities.

RESULTS

A total of 718,289 patients met inclusion criteria and 7,618 patients (1.06%) experienced VTE, including deep-vein thrombosis (n = 6,394, 0.9%) and/or pulmonary embolism (n = 2,211, 0.3%). A total of 10,769 patients (1.5%) filled perioperative thromboprophylaxis, including aspirin (n = 5,353, 0.7%), low-molecular-weight heparin (n = 4,563, 0.6%), and oral factor Xa inhibitors (n = 947, 0.1%). Perioperative thromboprophylaxis was associated with decreased odds of experiencing VTE (adjusted odds ratio [aOR] 0.65, 95% confidence interval [CI] 0.51-0.80). Procedure types categorized as moderate-to-greater risk were associated with increased odds of VTE (aOR 1.42, 95% CI 1.34-1.50). OCP use (aOR 1.63, 95% CI 1.38-1.91), obesity (aOR 1.17, 95% CI 1.11-1.24), renal disease (aOR 1.33, 95% CI 1.18-1.50) and congestive heart failure (aOR 1.30, 95% CI 1.13-1.50) were associated with increased odds of VTE.

CONCLUSIONS

While the overall rate of symptomatic VTE following knee arthroscopy remains low, procedure types that are more complex and generally require restrictive rehabilitation protocols, OCP use, obesity, renal disease, and congestive heart failure are associated with increased odds of postoperative VTE. Conversely, the use of perioperative thromboprophylaxis is associated with significantly lower VTE risk.

LEVEL OF EVIDENCE

III, retrospective comparative prognostic trial.

Trends in Surgical Treatment of Proximal Humeral Fractures and Analysis of Postoperative Complications Over a Decade in 384,158 Patients

Surgical treatment options for proximal humeral fractures include hemiarthroplasty (HA), reverse shoulder arthroplasty (RSA), and open reduction and internal fixation (ORIF). The objectives of this study were to analyze the trends in surgical treatment of proximal humeral fractures across a decade and to compare complications, reoperation rates, and readmission rates between ORIF and RSA.

METHODS

The PearlDiver MUExtr Database was used to identify patients with proximal humeral fractures who were treated with ORIF, HA, or RSA between 2010 and 2019 and analyze yearly trends. Complications, revision procedures, demographic characteristics, comorbidities, and emergency room visits and hospital readmissions within 90 days of the surgical procedure were compared between ORIF and RSA cohorts for patients who had at least 2-year follow-up data.

RESULTS

In this study, 384,158 patients with proximal humeral fractures were identified in the 10-year period between 2010 and 2019. There was a significant increase in the frequency of RSA and a decrease in the frequency of ORIF and HA over time (p < 0.0001). Compared with patients who underwent ORIF or HA, patients who underwent RSA were more likely to be older (p < 0.0001), to be female, and to have a higher Charlson Comorbidity Index. Patients who underwent ORIF had higher complication rates (23.03% compared with 18.62%; p < 0.0001) and higher reoperation rates (20.3% compared with 10.3%; p < 0.0001) than patients who underwent RSA. Patients who underwent RSA had higher emergency room visit rates (20.0% compared with 16.7%; p < 0.001) and hospital readmission rates (12.9% compared with 7.3%; p < 0.0001) within 90 days of the surgical procedure compared with patients who underwent ORIF.

CONCLUSIONS

There has been an increasing trend in RSA utilization for the surgical treatment of proximal humeral fractures, along with a decreasing trend in HA and ORIF, over time. Patients who underwent ORIF for a proximal humeral fracture had higher complication and reoperation rates compared with patients who underwent RSA. Patients who underwent RSA had higher emergency room visit and hospital readmission rates within 90 days of the surgical procedure compared with patients who underwent ORIF, which may be attributable to the RSA cohort being older and having more comorbidities.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Utilization of Autologous Chondrocyte Implantation in the Knee is Increasing While Reoperation Rates Are Decreasing Despite Increasing Preoperative Comorbidities

PURPOSE

The primary purpose of this study was to assess the use of autologous chondrocyte implantation (ACI) procedures in the knee during last decade, and the secondary aims of the study were to determine reoperation rates after ACI and to identify associated risk factors.

METHODS

A retrospective cohort study from 2010-2020 was performed using the PearlDiver database. The database was queried for the Current Procedural Terminology (CPT) code for ACI performed in any knee location, including the patellofemoral and tibiofemoral joints. Reoperation was defined as interventional knee procedures or total knee arthroplasty after ACI. Reoperations were identified using CPT and International Classification of Diseases codes. Univariate and multivariate logistic regression were used to identify risk factors for reoperation. Significance was defined as P < .05.

RESULTS

Among the 2010 patients included in this study, there were 90-day and overall reoperation rates of 2.24% and 30.4%, respectively, with an average follow up of 4.8 ± 3.3 years. The most common reoperations included chondroplasty, meniscectomy, and microfracture. There was an increased rate of ACI performed from 2017-2019 (5.53/100,000) compared to 2014-2016 (4.16/100,000; P < .001). ACI surgeries performed in 2017-2019 were associated with decreased risk of reoperation within 2 years relative to 2014-2016 (odds ratio [OR] = 0.70; 95% confidence interval [CI], 0.52-0.94; P = .019). In the entire ACI cohort, older age (OR = 1.07; 95% CI, 1.05-1.09; P < .001) and tobacco use (OR = 2.13; 95% CI, 1.06-3.94; P = .022) were associated with increased risk of conversion to arthroplasty. Male sex was associated with decreased overall reoperation rates (OR = 0.73; 95% CI, 0.60-0.89; P = .002).

CONCLUSIONS

There has been increasing use of ACI in the knee with decreased risk of reoperation since 2017 and the introduction of matrix-associated autologous chondrocyte implantation. Older age and tobacco use were predictors of increased risk of conversion to arthroplasty. Male sex was associated with decreased risk of reoperation.

LEVEL OF EVIDENCE

Level IV, retrospective cohort design; database study.

Risk for recurrent instability and reoperation following arthroscopic and open shoulder stabilization in a large cross-sectional population

Background

Recurrent shoulder instability is an orthopedic problem with potentially long-term functional ramifications. Although arthroscopic stabilization has become increasingly utilized over open stabilization, optimal surgical intervention to minimize recurrent instability remains controversial.

Methods

The PearlDiver Mariner database was queried for all cases of open and arthroscopic shoulder stabilization from 2010 to 2019. Utilization trends were aggregated after identifying cohorts of 107,210 and 13,217 patients who respectively underwent arthroscopic or open stabilization using Current Procedural Terminology codes. Subsets from those cohorts with laterality-specific International Classification of Diseases, Tenth Revision codes for shoulder instability were used to evaluate 2-year rates of recurrent instability (presence of shoulder dislocation or revision open or arthroscopic stabilization). Linear regression and chi-squared analysis were used to analyze utilization trends and to compare recurrent instability.

Results

Arthroscopic stabilization comprised 90% of all stabilization procedures with annual utilization continuing to increase into 2019. Latarjet utilization increased from 15% to 42% of all open stabilization procedures while open Bankart repair utilization decreased from 56% to 35%. The rate of recurrent instability was 10.2% after arthroscopic stabilization and 12.3% after open stabilization (P = .01). Rates of redislocation (4.0% vs. 2.6%, P < .01), conversion to shoulder arthroplasty (1.2% vs. 0.4%, P < .01), and revision open stabilization (6.8% vs. 2.3%, P < .01) after index open stabilization were significantly higher than after index arthroscopic stabilization. There was no difference in revision stabilization or dislocation rates between open procedures.

Conclusion

Despite increasing utilization of coracoid transfer, arthroscopic stabilization is still the dominant modality used for surgical treatment of shoulder instability and in our analysis, showed lower 2-year rates of dislocation, revision open stabilization, and conversion to shoulder arthroplasty.

Dyslipidemia is associated with risk for rotator cuff repair failure: a systematic review and meta-analysis

Background

Lipid deposition secondary to dyslipidemia (DLD) is shown to have a significant impact on tendon pathology, including tendon elasticity, fatty infiltration, and healing properties. Rotator cuff repair is a common procedure, susceptible to influence from many tear-related and patient-related characteristics. The purpose of this study was to determine the relationship between DLD and rotator cuff repair outcomes with analysis of retear risk and function.

Methods

PubMed, Embase, and SPORTDiscus were searched for all English-language, peer-reviewed studies between 2000 and the present, which analyzed relationships between patient-related factors and outcomes of rotator cuff repair. Studies that explicitly examined the effect of DLD on rotator cuff repair outcomes were chosen for inclusion. Included studies were assessed for methodological quality, and data were extracted for meta-analysis.

Results

Of the 3087 titles, 424 were screened by abstract, and 67 were reviewed in full. Inclusion criteria were met by 11 studies. Of these studies, 5 studies assessed retear, 2 studies measured function, 3 studies reported both retear and function, and 1 study evaluated the risk of retear necessitating a revision surgery. The studies report no significant difference in functional outcomes. Meta-analysis revealed that DLD patients had a significantly higher risk of retear after primary rotator cuff repair (odds ratio 1.32, 95% confidence interval 1.06-1.64).

Conclusion

DLD leads to an increased risk of retear after rotator cuff repair, although function appears to be unimpaired. DLD should be considered among other risk factors when counseling patients regarding expected rotator cuff repair outcomes.

Point-of-care motion capture and biomechanical assessment improve clinical utility of dynamic balance testing for lower extremity osteoarthritis

Musculoskeletal conditions impede patient biomechanical function. However, clinicians rely on subjective functional assessments with poor test characteristics for biomechanical outcomes because more advanced assessments are impractical in the ambulatory care setting. Using markerless motion capture (MMC) in clinic to record time-series joint position data, we implemented a spatiotemporal assessment of patient kinematics during lower extremity functional testing to evaluate whether kinematic models could identify disease states beyond conventional clinical scoring. 213 trials of the star excursion balance test (SEBT) were recorded by 36 subjects during routine ambulatory clinic visits using both MMC technology and conventional clinician scoring. Conventional clinical scoring failed to distinguish patients with symptomatic lower extremity osteoarthritis (OA) from healthy controls in each component of the assessment. However, principal component analysis of shape models generated from MMC recordings revealed significant differences in subject posture between the OA and control cohorts for six of the eight components. Additionally, time-series models of subject posture change over time revealed distinct movement patterns and reduced overall postural change in the OA cohort compared to the controls. Finally, a novel metric quantifying postural control was derived from subject specific kinematic models and was shown to distinguish OA (1.69), asymptomatic postoperative (1.27), and control (1.23) cohorts (p = 0.0025) and to correlate with patient-reported OA symptom severity (R = -0.72, p = 0.018). Time series motion data have superior discriminative validity and clinical utility than conventional functional assessments in the case of the SEBT. Novel spatiotemporal assessment approaches can enable routine in-clinic collection of objective patient-specific biomechanical data for clinical decision-making and monitoring recovery.

Muscle-Derived Beige Adipose Precursors Secrete Promyogenic Exosomes That Treat Rotator Cuff Muscle Degeneration in Mice and Are Identified in Humans by Single-Cell RNA Sequencing

BACKGROUND

Muscle atrophy, fibrosis, and fatty infiltration are common to a variety of sports-related and degenerative conditions and are thought to be irreversible. Fibroadipogenic progenitors (FAPs) are multipotent resident muscle stem cells with the capacity to differentiate into fibrogenic as well as white and beige adipose tissue (BAT). FAPs that have assumed a BAT differentiation state (FAP-BAT) have proven efficacious in treating muscle degeneration in numerous injury models.

PURPOSE

To characterize the subpopulation of murine FAPs with FAP-BAT activity, determine whether their promyogenic effect is mediated via exosomes, and analyze human FAPs for an analogous promyogenic exosome-rich subpopulation.

STUDY DESIGN

Controlled laboratory study.

METHODS

FAPs from UCP1 reporter mice were isolated via fluorescence-activated cell sorting and sorted according to the differential intensity of the UCP1 signal observed: negative for UCP1 (UCP1-), intermediate intensity (UCP1+), and high intensity (UCP1++). Bulk RNA sequencing was performed on UCP1-, UCP1+, and UCP1++ FAPs to evaluate distinct characteristics of each population. Exosomes were harvested from UCP1++ FAP-BAT exosomes (Exo-FB) as well as UCP1- non-FAP-BAT exosomes (Exo-nFB) cells using cushioned-density gradient ultracentrifugation and used to treat C2C12 cells and mouse embryonic fibroblasts in vitro, and the myotube fusion index was assessed. Exo-FB and Exo-nFB were then used to treat wild type C57B/L6J mice that had undergone a massive rotator cuff tear. At 6 weeks mice were sacrificed, and supraspinatus muscles were harvested and analyzed for muscle atrophy, fibrosis, fatty infiltration, and UCP1 expression. Single-cell RNA sequencing was then performed on FAPs isolated from human muscle that were treated with the beta-agonist formoterol or standard media to assess for the presence of a parallel promyogenic subpopulation of FAP-BAT cells in humans.

RESULTS

Flow cytometry analysis of sorted UCP1 reporter mouse FAPs revealed a trimodal distribution of UCP1 signal intensity, which correlated with 3 distinct transcriptomic profiles characterized with bulk RNA sequencing. UCP1++ cells were marked by high mitochondrial gene expression, BAT markers, and exosome surface makers; UCP1- cells were marked by fibrogenic markers; and UCP1+ cells were characterized differential enrichment of white adipose tissue markers. Exo-FB treatment of C2C12 cells resulted in robust myotube fusion, while treatment of mouse embryonic fibroblasts resulted in differentiation into myotubes. Treatment of cells with Exo-nFB resulted in poor myotube formation. Mice that were treated with Exo-FB at the time of rotator cuff injury demonstrated markedly reduced muscle atrophy and fatty infiltration as compared with treatment with Exo-nFB or phosphate-buffered saline. Single-cell RNA sequencing of human FAPs from the rotator cuff revealed 6 distinct subpopulations of human FAPs, with one subpopulation demonstrating the presence of UCP1+ beige adipocytes with a distinct profile of BAT, mitochondrial, and extracellular vesicle-associated markers.

CONCLUSION

FAP-BAT cells form a subpopulation of FAPs with upregulated beige gene expression and exosome production that mediate promyogenic effects in vitro and in vivo, and they are present as a transcriptomically similar subpopulation of FAPs in humans.

CLINICAL RELEVANCE

FAP-BAT cells and their exosomes represent a potential therapeutic avenue for treating rotator cuff muscle degeneration.

Microenergy acoustic pulses promotes muscle regeneration through in situ activation of muscle stem cells

Microenergy acoustic pulses (MAP) is a modified low-intensity extracorporeal shock wave therapy that currently used for treating musculoskeletal disorders. However, its function on muscle regeneration after ischemia-reperfusion injury (IRI) remains unknown. This study aimed to explore the effect of MAP on muscle injury after IRI and its underlying mechanisms. Ten-week-old C57BL/6J mice underwent unilateral hindlimb IRI followed with or without MAP treatment. Wet weight of tibialis anterior muscles at both injury and contralateral sides were measured followed with histology analysis at 3 weeks after IRI. In in vitro study, the myoblasts, endothelial cells and fibro-adipogenic progenitors (FAP) were treated with MAP. Cell proliferation and differentiation were assessed, and related gene expressions were measured by real-time PCR. Our results showed that MAP significantly increased the muscle weight and centrally nucleated regenerating muscle fiber size along with a trend in activating satellite cells. In vitro data indicated that MAP promoted myoblast proliferation and differentiation and endothelial cells migration. MAP also induced FAP brown/beige adipogenesis, a promyogenic phenotype of FAPs. Our findings demonstrate the beneficial function of MAP in promoting muscle regeneration after IR injury by inducing muscle stem cells proliferation and differentiation.

Biceps Tenodesis Demonstrates Lower Reoperation Rates Compared to SLAP Repair for Treatment of SLAP Tears in a Large Cross-Sectional Population

PURPOSE

To use a contemporary cross-sectional data set to evaluate trends in surgical treatment for superior labrum anterior and posterior (SLAP) tears and compare surgical outcomes with respect to 2-year revision surgery rates following index SLAP repair versus biceps tenodesis (BT).

METHODS

Patients diagnosed with a SLAP tear between 2010 and 2017 were queried using the Mariner PearlDiver database and stratified by demographic variables and surgical treatment with arthroscopic SLAP repair or arthroscopic/open BT. From 2015 to 2017, Current Procedural Terminology (CPT) and International Classification of Diseases 10th revision (ICD-10) codes were used to track ipsilateral subsequent reoperation within 2-years of index surgery.

RESULTS

Between 2010 to 2017, 16.6% of 377,463 patients diagnosed with a SLAP tear underwent surgery (62.3% SLAP repair vs 37.7% BT). 52.4% of BT procedures were arthroscopic (47.6% open). The frequency of SLAP repairs decreased from 74.0% to 46.2% (61%), while the frequency of BTs increased from 26.0% to 53.8% (202%) during the study period. Patients under age 50 were more likely to undergo SLAP repair, and those undergoing BT were more likely to be over 50 with higher CCI and comorbidity risk. 6.3% of 16,186 patients identified with ICD-10 coding required reoperation within 2-years postoperatively. SLAP repair demonstrated a higher revision rate (6.8%; 95% CI, 6.3-7.4%) than BT (5.7%; 95% CI, 5.2-6.2%; P =.0002), (open 5.8% vs arthroscopic BT 5.5%). Arthroscopic debridement, including biceps tenotomy, revision SLAP repair, and revision BT were the most common subsequent procedures. Patients aged 40 to 49 had the highest rate of revision surgery (7.8%).

CONCLUSIONS

The treatment trend for SLAP tears is changing, with SLAP repair becoming significantly less utilized and BT now becoming the preferred option, especially in patients over 50. Arthroscopic and open BT demonstrated slightly lower risk for reoperation than SLAP repair.

LEVEL OF EVIDENCE

IV, cross-sectional study.

Orthopedic sleep and novel analgesia pathway: a prospective randomized controlled trial to advance recovery after shoulder arthroplasty

BACKGROUND

Lack of sleep is associated with adverse effects on postsurgical pain and recovery. We hypothesized that a multimodal sleep pathway, including nonpharmacologic sleep hygiene interventions and the use of zolpidem and melatonin, could improve patient analgesia and sleep after total shoulder arthroplasty.

METHODS

We performed a prospective randomized controlled study in which patients undergoing anatomic and reverse total shoulder arthroplasty were treated with or without an interventional multimodal sleep pathway. This pathway included nursing-directed nonpharmacologic measures that promote sleep hygiene and pharmacologic interventions with low-dose zolpidem and melatonin at bedtime. All patients underwent a standardized multimodal analgesia protocol with scheduled acetaminophen, naproxen, and gabapentin, as well as a single-shot interscalene regional nerve block.

RESULTS

This study enrolled 125 patients (64 in control group and 61 in interventional group) with similar demographic characteristics. The interventional group showed less oral morphine milligram equivalent (MME) consumption on postoperative day (POD) 0 (44.8 ± 36.1 MMEs vs. 60.9 ± 42.1 MMEs, P = .01) and showed a trend toward lower POD 0 visual analog scale pain scores (2.6 ± 1.8 vs. 3.3 ± 3.0, P = .06). Visual analog scale pain scores and MME consumption were similar on POD 1. The interventional group showed a longer objective sleep duration by quantitative wrist actigraphy (5.9 ± 3.1 hours vs. 4.6 ± 2.7 hours, P = .008), with better sleep quality assessed by the Leeds Sleep Evaluation Questionnaire (0-100 scale; 50.3 ± 26.8 vs. 38.5 ± 27.8, P = .01). The 2 groups showed similar satisfaction with pain management (89.2% vs. 79.6%, P = .16) and sleep management (82.1% vs. 76.8%, P = .48). There was no difference in the length of inpatient stay (32.2 ± 14.8 hours vs. 34.1 ± 12.8 hours, P = .44).

CONCLUSION

In the setting of a regional and multimodal analgesia recovery plan for shoulder arthroplasty patients undergoing inpatient observation, the use of an interventional sleep pathway appears to be safe and beneficial, with improved analgesia, reduced opioid use, increased sleep duration, and improved reported sleep quality during the postoperative recovery period.

Factors Associated With Shoulder Activity Level at Time of Surgery and at 2-Year Follow-up in Patients Undergoing Shoulder Stabilization Surgery

BACKGROUND

Patients undergoing shoulder stabilization surgery have been shown to have elevated activity levels. Factors associated with shoulder activity in this patient population at baseline and after surgery are unknown.

HYPOTHESIS

Patient-specific variables are associated with shoulder activity level at baseline and at 2-year follow-up in a cohort of patients undergoing shoulder stabilization surgery.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Patients undergoing shoulder stabilization surgery were prospectively enrolled. As part of the data collection process, patients completed a previously validated Shoulder Activity Scale. A regression analysis was performed to assess the association of patient characteristics with baseline and 2-year follow-up shoulder activity levels.

RESULTS

A total of 764 (n = 612 men, n = 152 women) out of 957 patients (80%) undergoing shoulder stabilization surgery with a median age of 25 years had baseline and 2-year follow-up data and were included in the current analysis. The baseline shoulder activity level was associated with race ( P < .0001) and preoperative duration of instability (P < .0001). At 2 years, 52% of the cohort had returned to the same or higher activity level after surgery. Predictors of higher shoulder activity level at 2-year follow-up included higher baseline activity level (P < .0001), male sex (P < .0001), younger age (P = .004), higher body mass index (BMI) (P = .03), more dislocations (P = .03), nonsmokers (P = .04), and race (P = .04).

CONCLUSION

A longer duration of preoperative symptoms was associated with a lower baseline activity in this cohort. High baseline preoperative shoulder activity, younger age, male sex, higher BMI, number of dislocations, and nonsmoking status predicted higher shoulder activity 2 years after shoulder stabilization surgery.

REGISTRATION

NCT02075775 (ClinicalTrials.gov identifier).

Prior Bone Marrow Stimulation Surgery Influences Outcomes After Cell-Based Cartilage Restoration: A Systematic Review and Meta-analysis

Background:

Cell-based cartilage restoration with autologous chondrocyte implantation (ACI) is a safe and effective treatment for symptomatic cartilage lesions. Many patients undergoing ACI have a history of prior surgery, including bone marrow stimulation (BMS). There is mounting evidence that a history of prior BMS may impede healing of the ACI graft.

Purpose/Hypothesis:

The purpose of this study was to compare the failure rates of primary ACI with ACI after prior BMS. We hypothesized that ACI after BMS would have a significantly higher failure rate (defined as reoperation, conversion to arthroplasty, and/or imaging-based failure) compared with primary ACI.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A literature search was performed by use of PubMed and Embase databases for relevant articles published through October 2, 2020, to identify studies evaluating outcomes and failures rates of ACI after prior BMS in the knee.

Results:

Included were 11 studies comprising 1479 ACI procedures. The mean age at surgery ranged from 18.3 to 39.1 years, and the mean follow-up ranged from 3 to 20.6 years. All studies reported failure rates. The overall failure rate was significantly higher in the patients who underwent ACI after BMS, at 26.4% compared with 14.8% in the ACI group (P < .001). Meta-analysis demonstrated an increased risk of failure in patients with a history of prior BMS (log odds ratio = –0.90 [95% confidence interval, –1.38 to –0.42]).

Conclusion:

This systematic review demonstrated that failure rates were significantly higher for patients treated with ACI after BMS relative to patients undergoing ACI without prior BMS. This finding has important implications when considering the use of BMS for defects that are amenable to cell-based restoration and when determining treatment options after failed BMS.

Registration:

PROSPERO (CRD42020180387).

Low socioeconomic status worsens access to care and outcomes for rotator cuff repair: a scoping review

Background

Poor socioeconomic status (SES) is consistently associated with poor quality of health care, particularly in the field of orthopedics. Expanding insurance coverage has created a larger patient population by specifically making health care more accessible, translating to greater demand for care in the low-SES population. The purpose of this article is to provide a scoping review of literature observing access and outcomes of rotator cuff repair surgery among low-SES populations.

Methods

We performed a systematic review of articles using PubMed, Embase, and EBSCO (May 2021) from 2010 onward. Peer-reviewed articles that recorded at least one SES measure specific to patients who underwent rotator cuff repair from the United States were included. SES measures were methodically defined as income, occupation, employment, education, and race. All data that aligned with these SES measures were extracted.

Results

Of the 1009 titles reviewed, 109 studies were screened by abstract, 23 were reviewed in full, and 7 studies met criteria for inclusion. Of the 5 studies investigating access, all 5 found disparities among postoperative physical therapy, orthopedic consult, and surgery, using Medicaid status as a proxy for income in addition to other income measures. Of the 3 studies analyzing outcomes, 2 found that low-SES patients had worse pain and function, again based on Medicaid status and other income measures. Education did not have a significant impact on outcomes, as per the 1 study that included it. No studies included measures of occupation or employment.

Conclusion

Patients of low SES face reduced access to cuff repair care and worse associated outcomes, despite federal and state government efforts to reduce health care disparity through health care reform. The small nature of this review reflects how measures of SES are often not examined in rotator cuff repair studies.

Evaluating Utilization Trends in Adhesive Capsulitis of the Shoulder: A Retrospective Cohort Analysis of a Large Database

Background:

Nonoperative and operative treatment modalities have been used for symptom management of adhesive capsulitis, but neither has been shown to significantly alter the long-term natural history.

Purpose/Hypothesis:

The purpose was to evaluate the current trends in resource and treatment strategy utilization for patients with adhesive capsulitis. It was hypothesized that (1) patients with idiopathic adhesive capsulitis will primarily undergo nonoperative treatment and (2) patients with systemic medical comorbidities will demonstrate relatively higher utilization of nonoperative therapies.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

We searched the Mariner/PearlDiver database for Current Procedural Terminology and International Classification of Diseases codes to identify patients with adhesive capsulitis from 2010 to 2020 and to track their usage of diagnostic and therapeutic modalities, including radiography, magnetic resonance imaging (MRI), physical therapy, surgery, opioids, and injection. Patients with active records 1 year before and 2 years after initial diagnosis of adhesive capsulitis were eligible. Excluded were patients with secondary causes of adhesive capsulitis, such as fracture, infection, prior surgery, or other intra-articular pathology.

Results:

The median age of this 165,937-patient cohort was 58 years, with 67% being women. There was a high prevalence of comorbid diabetes (44.2%), thyroid disorder (29.6%), and Dupuytren contracture (1.3%). Within 2 years of diagnosis of adhesive capsulitis, diagnostic and therapeutic modality utilization included radiography (47.2%), opioids (46.7%), physical therapy (43.1%), injection (39.0%), MRI (15.8%), arthroscopic surgery (2.7%), and manipulation under anesthesia (2.5%). Over 68% of the diagnostic and therapeutic modalities were rendered from 3 months before to 3 months after diagnosis. Patients with diabetes, thyroid disorders, tobacco use, and obesity had greater odds for treatment with physical therapy, opioids, radiography, and injection when compared with patients without these comorbidities (odds ratio [OR] range, 1.05-2.21; P < .0001). Patients with diabetes and thyroid disorders had decreased odds for surgery (OR range, 0.88-0.91; P ≤ .003). Patients with Dupuytren contracture had increased odds for all therapeutic modalities (OR range, 1.20-1.68; P < .0001).

Conclusion:

Patients with adhesive capsulitis underwent primarily nonoperative treatment, with a high percentage utilizing opioids. The most active periods for treatment were from 3 months before diagnosis to 3 months after, and patients with medical comorbidities were more likely to undergo nonoperative treatment.

Outpatient Shoulder Arthroplasty-A Systematic Review

Objective

Recent reports have shown that outpatient shoulder arthroplasty (SA) may be a safe alternative to inpatient management in appropriately selected patients. The purpose was to review the literature reporting on outpatient SA.

Methods

A systematic review of publications on outpatient SA was performed. Included publications discussed patients who were discharged on the same calendar day or within 23 hours from surgery. Articles were categorized by discussions on complications, readmissions, and safety, patient selection, pain management strategies, cost effectiveness, and patient and surgeon satisfaction.

Results

Twenty-six articles were included. Patients undergoing outpatient SA were younger and with a lower BMI than those undergoing inpatient SA. Larger database studies reported more medical complications for patients undergoing inpatient compared to outpatient SA. Articles on pain management strategies discussed both single shot and continuous interscalene blocks with similar outcomes. Both patients and surgeons reported high levels of satisfaction following outpatient SA, and cost analysis studies demonstrated significant cost savings for outpatient SA.

Conclusion

In appropriately selected patients, outpatient SA can be a safe, cost-saving alternative to inpatient care and may lead to high satisfaction of both patients and physicians, though further studies are needed to clarify appropriate utilization of outpatient SA.

Rotator Cuff Tear Size Regulates Fibroadipogenic Progenitor Number and Gene Expression Profile in the Supraspinatus Independent of Patient Age

BACKGROUND

Fatty infiltration of rotator cuff muscle is a limiting factor in the success of repairs. Fibroadipogenic progenitors (FAPs) are a population of stem cells within the rotator cuff that can differentiate into white adipocytes, fibroblasts, and beige adipocytes. The effects of patient age and rotator cuff tendon tear size on the number, differentiation patterns, and gene expression profiles of FAPs have not yet been analyzed.

PURPOSE

To determine if patient age and rotator cuff tear size independently regulate FAP number, differentiation patterns, and gene expression profiles.

STUDY DESIGN

Controlled laboratory study.

METHODS

Supraspinatus muscle samples were collected from 26 patients between the ages of 42 and 76 years with partial- or full-thickness rotator cuff tears. FAPs were quantified using fluorescence-activated cell sorting. Gene expression analysis was performed across a custom 96-gene panel using NanoString. In vitro differentiation assays of FAPs were conducted using adipogenic, fibrogenic, and beige-inducing (amibegron-treated) media, and quantitative polymerase chain reaction was used to assess gene expression differences between adipogenic and amibegron media conditions. Multivariable linear regressions were performed using Stata to independently analyze the effects of age and rotator cuff tear size on FAP number, differentiation, and gene expression.

RESULTS

Increasing age and tear size were independently correlated with increased FAP number (β_age = 0.21, P = .03; β_{tear size} = 3.86, P = .05). There was no clear association between age and gene expression of freshly sorted FAPs. Under adipogenic and fibrogenic media conditions, increasing age and tear size were independently associated with increased adipogenic and fibrogenic differentiation of FAPs. Under amibegron treatment conditions, age positively correlated with increased beige differentiation (β = 1.03; P < .0001), while increasing tear size showed a trend toward decreased beige differentiation (β = -4.87; P = .1). When gene expression patterns between adipogenic and amibegron media conditions were compared, larger tear size strongly inhibited beige gene expression, while advanced age did not.

CONCLUSION

Patient age and rotator cuff tear size independently regulated FAP number, differentiation, and gene expression. Age and tear size were positively correlated with increased FAP number and fibrogenic/adipogenic differentiation. Advancing patient age did not limit FAP beige differentiation and gene expression, while increasing rotator cuff tear size strongly inhibited these processes.

Arthroscopic Rotator Cuff Repair Results in Lower Two-Year Reoperation Rates Compared With Open Rotator Cuff Repair in a Large Cross-sectional Cohort

PURPOSE

To use a large, contemporary database to perform a cross-sectional analysis of current practice trends in rotator cuff repair (RCR) for the treatment of full-thickness rotator cuff tear (RCT) and determine outcomes of arthroscopic and open RCR, including hospital readmissions and 2-year reoperation rates with accurate laterality tracking using International Classification of Diseases, Tenth Revision (ICD-10) codes.

METHODS

The PearlDiver Mariner dataset was used to query patients with full-thickness RCTs from 2010 to 2017. Propensity-score matching was performed to account for differences in age and comorbidities and allow for comparison between those undergoing open RCR and arthroscopic RCR. Subsequent procedures were tracked using ICD-10 codes to identify ipsilateral surgery within 2 years of index surgery. Hospital and emergency department admission within 30 days of surgery were investigated.

RESULTS

Of 534,076 patients diagnosed with full-thickness RCT, 37% underwent RCR; 73% of which were arthroscopic. From 2010 to 2017, arthroscopic RCRs increased from 65% to 80%, whereas open RCRs decreased from 35% to 20% (P < .0001). Younger patients underwent arthroscopic RCR more frequently, and patients who underwent open RCR had greater rates of 30-day emergency department (7.0%) and hospital readmission (2.0%) compared with arthroscopic RCR (6.3%, 1.0%, respectively) (P < .0001). For 24,392 patients with ICD-10 coding and 2-year follow-up, 10.4% of patients required reoperation, with the most common procedure being revision RCR, and 1.3% required conversion to arthroplasty. Open RCRs were more likely to require subsequent surgery (11.3%) compared with arthroscopic RCR (9.5%) (P < .0001). Patients aged 50 to 59 had the greatest rate of reoperation (14.0%), but no patients younger than age 40 years required reoperation, and no patients younger than age 50 years required conversion to arthroplasty.

CONCLUSIONS

The frequency of arthroscopic RCR has continued to increase compared to open RCR. In this large cross-sectional analysis, arthroscopic RCR demonstrated lower 2-year reoperation rates and 30-day readmission rates compared to open RCR.

LEVEL OF EVIDENCE

III, cross-sectional study.