Patient-reported outcome differences for navigated and robot-assisted total hip arthroplasty frequently do not achieve clinically important differences: a systematic review

INTRODUCTION

Total hip arthroplasty (THA) using computer-assisted navigation (N-THA) and robot-assisted surgery (RA-THA) has been increasingly adopted to improve implant positioning and offset/leg-length restoration. Whether clinically meaningful differences in patient-reported outcomes (PROMs) compared to conventional THA (C-THA) are achieved with intraoperative technology has not been established. This systematic review aimed to assess whether published relative PROM improvements with technology use in THA achieved minimal clinically important differences (MCIDs).

METHODS

PubMed/MEDLINE/Cochrane Library were systematically reviewed for studies comparing PROMs for primary N-THA or RA-THA with C-THA as the control group. Relative improvement differences between groups were compared to established MCID values. Reported clinical and radiographic differences were assessed. Review of N-THA and RA-THA literature yielded 6 (n = 2580) and 10 (n = 2786) studies, respectively, for analyses.

RESULTS

Statistically significant improvements in postoperative PROM scores were reported in 2/6 (33.3%) studies comparing N-THA with C-THA, though only 1 (16.7%) reported clinically significant relative improvements. Statistically significant improvements in postoperative PROMs were reported in 6/10 (60.0%) studies comparing RA-THA and C-THA, though none reported clinically significant relative improvements. Improved radiographic outcomes for N-THA and RA-THA were reported in 83.3% and 70.0% of studies, respectively. Only 1 study reported a significant improvement in revision rates with RA-THA as compared to C-THA.

CONCLUSIONS

Reported PROM scores in studies comparing N-THA or RA-THA to C-THA often do not achieve clinically significant relative improvements. Future studies reporting PROMs should be interpreted in the context of validated MCID values to accurately establish the clinical impact of intraoperative technology.

Innovations in the Isolation and Treatment of Biofilms in Periprosthetic Joint Infection: A Comprehensive Review of Current and Emerging Therapies in Bone and Joint Infection Management

Periprosthetic joint infections (PJIs) are a devastating complication of joint arthroplasty surgeries that are often complicated by biofilm formation. The development of biofilms makes PJI treatment challenging as they create a barrier against antibiotics and host immune responses. This review article provides an overview of the current understanding of biofilm formation, factors that contribute to their production, and the most common organisms involved in this process. This article focuses on the identification of biofilms, as well as current methodologies and emerging therapies in the management of biofilms in PJI.

"Stuck in the middle": the missing lumbosacral link in total hip arthroplasty

INTRODUCTION

Spinopelvic mobility drives functional acetabular position, influencing dislocation risk after total hip arthroplasty (THA). Patients have been described as "stuck sitting" or "stuck standing" based on pelvic tilt (PT). We hypothesised that some patients are "stuck in the middle," meaning their PT changes minimally from sitting to standing - increasing their risk of dislocation.

METHODS

We reviewed 195 patients with standing and sitting whole body radiographs prior to THA. Standing anterior pelvic plane tilt (APPT) and standing and sitting sacral slope (SS) were measured and used to calculate sitting APPT. Normal standing and sitting were defined as APPT >-10° and <-20°, respectively. Spinal stiffness was classified as <10° change in sacral slope between sitting and standing. Patients were categorised as: (A) able to fully sit and stand; (B) "stuck sitting" - able to fully sit; unable to fully stand; (C) "stuck standing" - able to fully stand; unable to fully sit; or (D) "stuck in the middle" - unable to sit or stand fully.

RESULTS

84 patients could sit and stand normally (A), 22 patients were stuck sitting (B), 76 patients were stuck standing (C), and 13 patients were stuck in the middle (D). While 111 patients (56.9%) were considered stuck, only 58 patients (29.7%) met criteria for spinal stiffness.

DISCUSSION

We identified a subset of patients with stiff spines and abnormal PT in both sitting and standing, including 37.1% of patients who would be classified as "stuck sitting" based only on standing radiographs. Placing acetabular components in less than anatomic anteversion in these patients may increase posterior dislocation risk.

The Impact of Obesity on Total Hip Arthroplasty Outcomes When Performed by High-Volume Surgeons-A Propensity Matched Analysis From a High-Volume Urban Center

BACKGROUND

Previous data suggest that obesity does not impact surgical outcomes following total knee arthroplasty performed by high-volume (HV) surgeons. However, this effect has yet to be studied in total hip arthroplasty (THA) patients. This study aimed to evaluate the impact of patient obesity on THA outcomes when surgery is performed by HV surgeons.

METHODS

A retrospective analysis of patients who underwent primary, elective THA between January 2012 and December 2022 with a HV surgeon (top 25% of surgeons by number of annual primary THA) was performed. Patients were stratified by their body mass index (BMI) into 3 cohorts: BMI ≥ 40 (morbidly obese [MO]), 30 ≤ BMI < 40 (obese), and BMI < 30 (nonobese); and 1:1:1 propensity matched based on baseline characteristics. A total of 13,223 patients were evaluated, of which 669 patients were included in the final matched analysis (223 patients per group). The average number of annual THAs performed for HV surgeons was 171 cases.

RESULTS

The MO patients had significantly longer surgical times (P < .001) and hospital lengths of stay (P < .001). Rates of 90-day readmissions (P = .211) and all-cause, septic, and aseptic revisions at the latest follow-up (P = .268, P = .903, and P = .168, respectively) were comparable between groups. In a subanalysis for non-HV surgeons, MO patients had a significantly greater risk of revision (P = .021) and trended toward significantly greater readmissions (P = .056).

CONCLUSIONS

Clinical outcomes and complication rates after THA performed by a HV surgeon are similar regardless of patient obesity status. Patients who have MO may experience improved outcomes and reduced procedural risks if they are referred to HV surgeons.

LEVEL OF EVIDENCE

III.

The Financial Burden of Patient Comorbidities on Total Hip Arthroplasties-A Matched Cohort Analysis of High Comorbidity Burden and Non-High Comorbidity Burden Patients

BACKGROUND

The impact of increased patient comorbidities on the cost-effectiveness of total hip arthroplasty (THAs) is lacking. This study aimed to compare revenue, costs, and short-term (90 days) surgical outcomes between patients who have and do not have a high comorbidity burden (HCB).

METHODS

We retrospectively reviewed 14,949 patients who underwent an elective, unilateral THA between 2012 and 2021. Patients were stratified into HCB (Charlson Comorbidity Index ≥ 5 and American Society of Anesthesiology scores of 3 or 4) and non-HCB groups, and were further 1:1 propensity matched based on baseline characteristics. Perioperative data, revenue, costs, and contribution margins (CMs) of the inpatient episode were compared between groups. Also, 90-day readmissions and revisions were compared between groups. Of the 11,717 patients who had available financial data (n = 1,017 HCB, n = 10,700 non-HCB), 1,914 patients were included in the final matched analyses (957 per group).

RESULTS

Total (P < .001) and direct (P < .001) costs were significantly higher for HCB patients. Comparable revenue between cohorts (P = .083) resulted in a significantly decreased CM in the HCB patient group (P < .001). The HCB patients were less likely to be discharged home (P < .001) and had significantly higher 90-day readmission rates (P = .049).

CONCLUSIONS

Increased THA costs for HCB patients were not matched by increased revenue, resulting in decreased CM. Higher rates of nonhome discharge and readmissions in the HCB population add to the additional financial burden. Adjustments to the current reimbursement models should better account for the increased financial burden of HCB patients undergoing THA and ensure access to care for all patient populations.

LEVEL OF EVIDENCE

III.

Mid-term outcomes of a kinematically designed cruciate retaining total knee arthroplasty

BACKGROUND

Advances in implant material and design have allowed for improvements in total knee arthroplasty (TKA) outcomes. A cruciate retaining (CR) TKA provides the least constraint of TKA designs by preserving the native posterior cruciate ligament. Limited research exists that has examined clinical outcomes or patient reported outcome measures (PROMs) of a large cohort of patients undergoing a CR TKA utilizing a kinematically designed implant. It was hypothesized that the studied CR Knee System would demonstrate favorable outcomes and a clinically significant improvement in pain and functional scores.

AIM

To assess both short-term and mid-term clinical outcomes and PROMs of a novel CR TKA design.

METHODS

A retrospective, multi-surgeon study identified 255 knees undergoing a TKA utilizing a kinematically designed CR Knee System (JOURNEY™ II CR; Smith and Nephew, Inc., Memphis, TN) at an urban, academic medical institution between March 2015 and July 2021 with a minimum of two-years of clinical follow-up with an orthopedic surgeon. Patient demographics, surgical information, clinical outcomes, and PROMs data were collected via query of electronic medical records. The PROMs collected in the present study included the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) and Patient-Reported Outcomes Measurement Information System (PROMIS®) scores. The significance of improvements in mean PROM scores from preoperative scores to scores collected at six months and two-years postoperatively was analyzed using Independent Samples t-tests.

RESULTS

Of the 255 patients, 65.5% were female, 43.8% were White, and patients had an average age of 60.6 years. Primary osteoarthritis (96.9%) was the most common primary diagnosis. The mean surgical time was 105.3 minutes and mean length of stay was 2.1 d with most patients discharged home (92.5%). There were 18 emergency department (ED) visits within 90 d of surgery resulting in a 90 d ED visit rate of 7.1%, including a 2.4% orthopedic-related ED visit rate and a 4.7% non-orthopedic-related ED visit rate. There were three (1.2%) hospital readmissions within 90 d postoperatively. With a mean time to latest follow-up of 3.3 years, four patients (1.6%) required revision, two for arthrofibrosis, one for aseptic femoral loosening, and one for peri-prosthetic joint infection. There were significant improvements in KOOS JR, PROMIS Pain Intensity, PROMIS Pain Interference, PROMIS Mobility, and PROMIS Physical Health from preoperative scores to six month and two-year postoperative scores.

CONCLUSION

The evaluated implant is an effective, novel design offering excellent outcomes and low complication rates. At a mean follow up of 3.3 years, four patients required revisions, three aseptic and one septic, resulting in an overall implant survival rate of 98.4% and an aseptic survival rate of 98.8%. The results of our study demonstrate the utility of this kinematically designed implant in the setting of primary TKA.

Comparing Outcomes of Bicruciate-Stabilized and Cruciate-Retaining Total Knee Arthroplasty

Background

Bicruciate-stabilized (BCS) total knee arthroplasty (TKA) aims to restore normal kinematics by replicating the function of both cruciate ligaments. Conventional cruciate-retaining (CR) design in TKA has shown previous clinical success with lower complication rates. This study compared the patient-reported outcomes between the BCS and CR TKA designs.

Methods

This retrospective study examined patients who underwent primary TKA using a CR or a BCS implant. Patient demographics, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR), and Forgotten Joint Score (FJS) were compared between two cohorts. Patient-reported outcome measures were analyzed using independent samples t-tests.

Results

There were no significant preoperative demographic differences between groups. The CR cohort (n = 756) had significantly higher average KOOS, JR Scores compared to the BCS cohort (n = 652) at 3 months (59.7 ± 3.8 vs. 53.0 ± 3.9, p < 0.001) and 2 years (62.6 ± 8.0 vs. 53.8 ± 6.7, p = 0.001) after TKA. Within the cohort, KOOS, JR delta differences were not significant for CR when comparing patient scores 3 months to 1 year after surgery. Meanwhile, the BCS patients did show significant delta improvement (4.1 ± 1.9, p = 0.030) when compared 3 months to 1 year after surgery. One year postoperatively, the BCS cohort (n = 134) showed a significantly higher average FJS score (49.5 ± 31.4, vs. 36.8 ± 28.5, p = 0.028) than the CR cohort (n = 203). Both cohorts displayed a significant difference in delta improvements within their respective cohort when measuring FJS from 3 months to 1 year, 2 years, and 3 years after surgery.

Conclusions

The CR cohort performed better on average, compared to the BCS cohort in measures of KOOS, JR scores at the 2-year follow-up. The BCS cohort performed marginally better regarding FJS only at 1-year follow-up.

Does experience with total knee arthroplasty in morbidly obese patients effect surgical outcomes

INTRODUCTION

Literature examining the risks, benefits, and potential complications of TKA in morbidly obese patients is conflicting. Surgeons with more experience performing TKA on morbidly obese patients may generate superior outcomes. This study sought to assess whether complication rates and implant survivorship in morbidly obese TKA patients varies between high (HV) and low (LV) volume surgeons.

METHODS

A retrospective review was performed to include all morbidly obese (BMI ≥ 40) patients that underwent primary TKA between January 2016 and July 2021 at our high-volume center. Demographics and clinical outcomes were collected and compared between surgeons with a higher morbidly obese TKA volume (> 10 annual cases) and surgeons with a lower morbidly obese TKA volume.

RESULTS

A total of 964 patients (HV 91 [9.4%], LV 873 [90.6%]) were identified. The HV surgeon and LV surgeons had an average annual volume of 15.3 and 5.2 cases, respectively. The average BMI for the HV and LV cohorts were 44.5 ± 3.7 and 44.0 ± 3.6, respectively (p = 0.160). The HV surgeon had significantly lower operative times (105.7 ± 17.4 vs. 110.7 ± 29.6 min, p = 0.018), and a lower 90-day minor complication rate (0.0% vs. 4.7%, p = 0.035). For patients with at least 2-year follow-up, all-cause revision (3.4% vs. 12.5%, p = 0.149) and revision due to PJI (0.0% vs. 5.8%, 0.193) rates were numerically lower in the HV cohort. Improvements in KOOS, JR and VR-12 scores were similar at 3-month and 1-year follow-up. Freedom from all-cause revision (HV: 96.6% vs. LV: 80.4%, p = 0.175) and revision due to PJI (HV: 100.0% vs. LV: 93.6%, p = 0.190, p = 0.190) at latest follow-up did not statistically differ between groups.

CONCLUSION

The HV surgeon had significantly lower operative time and 90-day minor complication rates and numerically lower all-cause revision and revision due to PJI rates when performing TKA in morbidly obese patients. Surgeon's experience may affect surgical outcomes after TKA in morbidly obese patients.

LEVEL OF EVIDENCE

III.

Risk Stratification in Orthopaedics

Proper predictive tools are essential to guide patient selection, optimization, category of surgical admission (inpatient, outpatient surgery), and discharge disposition, and predict the risk of readmissions and complications after orthopaedic procedures. Therefore, identification and optimization of patients' perioperative risk for surgery is essential, and understanding these basic concepts is crucial to maximizing patient care quality. It is important to define risk, stratify the existing preoperative attributes, and review key concepts of patient-specific risk calculation and documentation.

Impact of a Novel Navigational Technology on Short-Term Patient Outcomes Following Total Knee Arthroplasty A Propensity Matched Cohort Study

PURPOSE

The use of intraoperative technology is increasing among orthopedic surgeons in the United States. However, there is continued debate as to whether intraoperative technologies provide clinical benefits in patients undergoing total knee arthroplasty (TKA). This study sought to determine whether the use of a novel intraoperative navigation technology produces equivalent or superior short-term outcomes compared to conventional technique.

METHODS

Fifty-nine consecutive patients underwent primary TKA with a novel imageless intraoperative navigational technology between October 2019 and January 2020 at a single, urban, orthopedic specialty hospital. A 1:1 cohort propensity matching was performed with patients with similar demographics who underwent primary TKA without the use of technology. Demographics, clinical data, as well as preoperative and 3-month Knee Injury and Osteoarthritis Outcome Score, Joint Replacement (KOOS, JR) scores were collected. Demographic differences, clinical data, and mean KOOS, JR scores were assessed using chi-squared analysis for categorical variables and independent sample t-test for continuous variables.

RESULTS

Upon 1:1 cohort matching, patients in both the navigational cohorts and non-navigational cohorts were statistically similar demographically. Length of stay (2.11 vs. 1.71 days; p = 0.108), surgical time (108.89 vs. 101.19 minutes, p = 0.066), discharge disposition (p = 0.675), 90- day readmissions (4 vs. 4, p = 0.999), and 90-day reoperations (2 vs. 2, p = 0.999) did not statistically differ between the two matched cohorts. Additionally, KOOS, JR scores evaluated between the two cohorts preoperatively (46.06 vs. 45.17, p = 0.836) and at 3-month follow-up (57.63 vs. 55.06, p = 0.580) were similar.

CONCLUSION

This study demonstrates that the use of this novel intraoperative navigational technology yields similar short-term TKA results when compared to conventionally performed TKA. Further studies are required to validate new technologies and determine their effect on long-term clinical and patient-reported outcomes.

Outcomes of medicaid patients undergoing TJA with previous positive urine toxicology screens

INTRODUCTION

Previous studies have demonstrated that patients with positive preoperative urine toxicology (utox) screens prior to total joint arthroplasty (TJA) have higher readmission rates, greater complication rates, and longer hospital stays compared to patients with negative screens. The aim of this study was to investigate the effect of postponing surgery for patients with positive preoperative utox in the Medicaid population.

METHODS

This retrospective, observational study reviewed the Medicaid ambulatory database at a large, academic orthopedic specialty hospital for patients with a utox screen prior to TJA from 2012 to 2020. Patients were categorized into three groups: (1) controls with negative preoperative utox or a utox consistent with prescription medications (Utox-) with TJA completed as scheduled; (2) positive preoperative utox with TJA rescheduled and surgery completed on a later date (R-utox+); (3) positive preoperative utox inconsistent with prescription medications with TJA completed as scheduled (S-utox+). Primary outcomes included mortality, 90-day readmission rate, complication rate, and length of stay.

RESULTS

Of the 300 records reviewed, 185 did not meet inclusion criteria. The remaining 115 patients included 80 (69.6%) Utox-, 5 (6.3%) R-utox+, and 30 (37.5%) S-utox+. Mean follow-up time was 49.6 months. Hospital stays trended longer in the Utox- group (3.7 ± 2.0 days vs. 3.1 ± 1.6 S-utox+ vs.2.5 ± 0.4 R-utox+, p = 0.20). Compared to the R-utox+group, the S-utox+ group trended toward lower home discharge rates (p = 0.20), higher in-hospital complication rates (p = 0.85), and more all-cause 90-day emergency department visits (p = 0.57). There were no differences in postoperative opioid utilization between groups (p = 0.319). Duration of postoperative narcotic use trended toward being longer in the Utox- patients (820.7 ± 1073.8 days vs. 684.6 ± 1491.8 S-utox+ vs. 585.1 ± 948.3 R-utox+, p = 0.585). Surgical time (p = 0.045) and revision rates (p = 0.72) trended toward being higher in the S-utox+ group.

CONCLUSIONS

Medicaid patients with positive preoperative utox who had surgeries postponed trended towards shorter hospital stays and greater home discharge rates. Larger studies should be conducted to analyze the implications of a positive preoperative utox on risk profiles and outcomes following TJA in the Medicaid population. Study design Retrospective cohort study.

Does the geriatric nutritional risk index predict complication rates and implant survivorship in revision total joint arthroplasty?

INTRODUCTION

Malnutrition is associated with poorer outcomes after revision total joint arthroplasty (rTJA), though no universal metric for assessing malnutrition in rTJA patients has been reported. This study sought to determine if malnutrition as defined by the Geriatric Nutritional Risk Index (GNRI) can independently predict short-term complication rates and re-revision risk in patients undergoing rTJA.

METHODS

All patients ≥ 65 years old undergoing rTJA from 2011 to 2021 at a single orthopaedic specialty hospital were identified. Preoperative albumin, height, and weight were used to calculate GNRI. Based on the calculated GNRI value, patients were stratified into three groups: normal nutrition (GNRI > 98), moderate malnutrition (GNRI 92-98), and severe malnutrition (GNRI < 92). Chi-squared and independent samples t-tests were used to compare groups.

RESULTS

A total of 531 rTJA patients were included. Patients with normal nutrition were younger (p < 0.001), had higher BMI (p < 0.001). After adjusting for baseline characteristics, patients with severe and moderate malnutrition had longer length of stay (p < 0.001), were less likely to be discharged home (p = 0.049), and had higher 90-day major complication (p = 0.02) and readmission (p = 0.005) rates than those with normal nutrition. 90-day revision rates were similar. In Kaplan-Meier analyses, patients with severe and moderate malnutrition had worse survivorship free of all-cause re-revision at 1-year (p = 0.001) and 2-year (p = 0.002) follow-up compared to those with normal nutrition.

CONCLUSION

Moderate and severe malnutrition, as defined by GNRI, independently predicted higher complication and revision rates in rTJA patients. This suggests that the GNRI may serve as an effective screening tool for nutritional status in patients undergoing rTJA.

The Impact of Surgeon Proficiency in Non-English-Speaking Patients' Primary Language on Outcomes After Total Joint Arthroplasty

Non-English-speaking patients face increased communication barriers when undergoing total joint arthroplasty (TJA). Surgeons may learn or have proficiency in languages spoken among their patients to improve communication. This study investigated the effect of surgeon-patient language concordance on outcomes after TJA. We conducted a single-institution, retrospective review of patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA) whose preferred language was not English. Patients were stratified based on whether their surgeon spoke their preferred language (language concordant [LC]) or not (language discordant [LD]). Baseline characteristics, length of stay, discharge disposition, revision rate, readmission rate, and patient-reported outcomes (Knee injury and Osteoarthritis Outcome Score for Joint Replacement [KOOS, JR], Hip disability and Osteoarthritis Outcome Score for Joint Replacement [HOOS, JR], and Patient-Reported Outcomes Measurement Information System [PROMIS]) were compared. A total of 3390 patients met inclusion criteria, with 855 receiving THA and 2535 receiving TKA. Among patients receiving THA, 440 (51.5%) saw a LC provider and 415 (48.5%) saw a LD provider. Those in the LC group had higher HOOS, JR scores at 1 year postoperatively (67.4 vs 49.3, P=.003) and were more likely to be discharged home (77.5% vs 69.9%, P=.013). Among patients receiving TKA, 1051 (41.5%) received LC care, whereas 1484 (58.5%) received LD care. There were no differences in outcome between the LC and LD TKA groups. Patients receiving THA with surgeons who spoke their language had improved patient-reported outcomes and were more commonly discharged home after surgery. Language concordance did not change outcomes in TKA. Optimizing language concordance for patients receiving TJA may improve postoperative outcomes. [Orthopedics. 2023;46(6):334-339.].

The Impact of Machine Learning on Total Joint Arthroplasty Patient Outcomes: A Systemic Review

BACKGROUND

Supervised machine learning techniques have been increasingly applied to predict patient outcomes after hip and knee arthroplasty procedures. The purpose of this study was to systematically review the applications of supervised machine learning techniques to predict patient outcomes after primary total hip and knee arthroplasty.

METHODS

A comprehensive literature search using the electronic databases MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews was conducted in July of 2021. The inclusion criteria were studies that utilized supervised machine learning techniques to predict patient outcomes after primary total hip or knee arthroplasty.

RESULTS

Search criteria yielded n = 30 relevant studies. Topics of study included patient complications (n = 6), readmissions (n = 1), revision (n = 2), patient-reported outcome measures (n = 4), patient satisfaction (n = 4), inpatient status and length of stay (LOS) (n = 9), opioid usage (n = 3), and patient function (n = 1). Studies involved TKA (n = 12), THA (n = 11), or a combination (n = 7). Less than 35% of predictive outcomes had an area under the receiver operating characteristic curve (AUC) in the excellent or outstanding range. Additionally, only 9 of the studies found improvement over logistic regression, and only 9 studies were externally validated.

CONCLUSION

Supervised machine learning algorithms are powerful tools that have been increasingly applied to predict patient outcomes after total hip and knee arthroplasty. However, these algorithms should be evaluated in the context of prognostic accuracy, comparison to traditional statistical techniques for outcome prediction, and application to populations outside the training set. While machine learning algorithms have been received with considerable interest, they should be critically assessed and validated prior to clinical adoption.

Are Patient Outcomes Affected by Surgeon Experience With Total Hip Arthroplasty in Morbidly Obese Patients?

Background

Surgeons with high volume (HV) of total hip arthroplasty (THA) have seen better outcomes than low volume (LV) surgeons. However, literature regarding surgeon volume and outcomes in morbidly obese THA patients is scarce. This study examines the association between surgeon volume with THA in morbidly obese patients (body mass index ≥40) and their clinical outcomes.

Methods

We retrospectively reviewed all morbidly obese patients who underwent primary THA at our institution between March 2012 and July 2020 with 2 years of follow-up. Clinical outcomes were compared between the HV (HVa, top quartile of surgeons with the highest overall yearly THA volume) and LV (LVa) surgeons. Similar analysis was run comparing HV of morbidly obese THA (HVo, top quartile of surgeons with the highest yearly morbidly obese THA volume) and LV of morbidly obese THA (LVo) surgeons.

Results

Six hundred and forty-three patients and 33 surgeons were included. HVa surgeons had significantly shorter length of stay and increased home discharge. HVa and HVo surgeons had significantly shorter operative times. There were no significant differences in overall 90-day major and minor complications or clinical differences in patient-reported outcomes. Revision rates and freedom from revisions did not differ between groups at 2-year follow-up.

Conclusions

HVa surgeons had significantly lower length of stay and operative times and increased discharge to home. There was no significant decrease in complications or revisions in either comparison model. Complications, revision rates, and patient satisfaction in morbidly obese patients who undergo THA may be independent of surgeon volume.

Creating Consensus in the Definition of Spinopelvic Mobility

INTRODUCTION

The term "spinopelvic mobility" is most often applied to motion within the spinopelvic segment. It has also been used to describe changes in pelvic tilt between various functional positions, which is influenced by motion at the hip, knee, ankle and spinopelvic segment. In the interest of establishing a consistent language for spinopelvic mobility, we sought to clarify and simplify its definition to create consensus, improve communication, and increase consistency with research into the hip-spine relationship.

METHODS

A literature search was performed using the Medline (PubMed) library to identify all existing articles pertaining to spinopelvic mobility. We reported on the varying definitions of spinopelvic mobility including how different radiographic imaging techniques are used to define mobility.

RESULTS

The search term "spinopelvic mobility" returned a total of 72 articles. The frequency and context for the varying definitions of mobility were reported. 41 papers used standing and upright relaxed-seated radiographs without the use of extreme positioning, and 17 papers discussed the use of extreme positioning to define spinopelvic mobility.

DISCUSSION

Our review suggests that the definitions of spinopelvic mobility is not consistent in the majority of published literature. We suggest descriptions of spinopelvic mobility independently consider spinal motion, hip motion, and pelvic position, while recognizing and describing their interdependence.

Impact of time to revision total knee arthroplasty on outcomes following aseptic failure

INTRODUCTION

Prior studies have demonstrated an association between time to revision total knee arthroplasty (rTKA) and indication; however, the impact of early versus late revision on post-operative outcomes has not been reported.

MATERIALS AND METHODS

A retrospective, observational study examined patients who underwent unilateral, aseptic rTKA at an academic orthopedic hospital between 6/2011 and 4/2020 with > 1-year of follow-up. Patients were early revisions if they were revised within 2 years of primary TKA (pTKA) or late revisions if revised after greater than 2 years. Patient demographics, surgical factors, and post-operative outcomes were compared.

RESULTS

470 rTKA were included (199 early, 271 late). Early rTKA patients were younger by 2.5 years (p = 0.002). The predominant indications for early rTKA were instability (28.6%) and arthrofibrosis/stiffness (26.6%), and the predominant indications for late rTKA were aseptic loosening (45.8%) and instability (26.2%; p < 0.001). Late rTKA had longer operative times (119.20 ± 51.94 vs. 103.93 ± 44.66 min; p < 0.001). There were no differences in rTKA type, disposition, hospital length of stay, all-cause 90-day emergency department visits and readmissions, reoperations, and number of re-revisions.

CONCLUSIONS

Aseptic rTKA performed before 2 years had different indications but demonstrated similar outcomes to those performed later. Early revisions had shorter surgical times, which could be attributed to differences in rTKA indication.

LEVEL OF EVIDENCE

III, retrospective observational analysis.

Multiply revised TKAs have worse outcomes compared to index revision TKAs

Aims

Revision total knee arthroplasty (rTKA) is a technically challenging and costly procedure. It is well-documented that primary TKA (pTKA) have better survivorship than rTKA; however, we were unable to identify any studies explicitly investigating previous rTKA as a risk factor for failure following rTKA. The purpose of this study is to compare the outcomes following rTKA between patients undergoing index rTKA and those who had been previously revised.

Methods

This retrospective, observational study reviewed patients who underwent unilateral, aseptic rTKA at an academic orthopaedic speciality hospital between June 2011 and April 2020 with > one-year of follow-up. Patients were dichotomized based on whether this was their first revision procedure or not. Patient demographics, surgical factors, postoperative outcomes, and re-revision rates were compared between the groups.

Results

A total of 663 cases were identified (486 index rTKAs and 177 multiply revised TKAs). There were no differences in demographics, rTKA type, or indication for revision. Multiply revised patients had significantly longer rTKA operative times (p < 0.001), and were more likely to be discharged to an acute rehabilitation centre (6.2% vs 4.5%) or skilled nursing facility (29.9% vs 17.5%; p = 0.003). Patients who had been multiply revised were also significantly more likely to have subsequent reoperation (18.1% vs 9.5%; p = 0.004) and re-revision (27.1% vs 18.1%; p = 0.013). The number of previous revisions did not correlate with the number of subsequent reoperations (r = 0.038; p = 0.670) or re-revisions (r = -0.102; p = 0.251).

Conclusion

Multiply revised TKA had worse outcomes, with higher rates of facility discharge, longer operative times, and greater reoperation and re-revision rates compared to index rTKA.

Trends in Complications and Outcomes in Patients Aged 65 Years and Younger Undergoing Total Hip Arthroplasty: Data From the American Joint Replacement Registry

This study sought to determine common complications and the rates of readmission and revision in total hip arthroplasty patients younger than 65 years. Using the American Joint Replacement Registry, we conducted a retrospective review of all THAs in patients aged 18 to 65 years from 2012 to 2020. We excluded patients aged older than 65 years, revisions, oncologic etiology, conversion from prior surgery, and nonelective cases. Primary outcomes included cumulative revision rate, 90-day readmission rate, and reason for revision. The Kaplan-Meier method and univariate analysis were used. Five thousand one hundred fifty-three patients were included. The average age was 56.7 years (SD 7.8 years), 51% were female, 85% were White, and 89% had a Charlson Comorbidity Index of 0 (1 = 7%, >2 = 4%). The mean follow-up was 39.57 months. Fifty-three patients (1.0%) underwent revision. Seventy-four patients (1.4%) were readmitted within 90 days. Revision was more common in Black patients (P = 0.023). Survivorship was 99% (95% confidence interval, 98.7 to 99.3) and 99% (95% confidence interval, 98.5 to 99.3) at 5 and 8 years, respectively. Infection (21%), instability (15%), periprosthetic fracture (15%), and aseptic loosening (9%) were the most common indications for revision. Total hip arthroplasty performed in young and presumed active patients had a 99% survivorship at 8 years. A long-term follow-up is needed to evaluate survival trends in this growing population.

The Use of Navigation or Robotic-Assisted Technology in Total Knee Arthroplasty Does Not Reduce Postoperative Pain

The use of intraoperative technology (IT), such as computer-assisted navigation (CAN) and robot-assisted surgery (RA), in total knee arthroplasty (TKA) is increasingly popular due to its ability to enhance surgical precision and reduce radiographic outliers. There is disputing evidence as to whether IT leads to better clinical outcomes and reduced postoperative pain. The purpose of this study was to determine if use of CAN or RA in TKA improves pain outcomes. This is a retrospective review of a multicenter randomized control trial of 327 primary TKAs. Demographics, surgical time, IT use (CAN/RA), length of stay (LOS), and opioid consumption (in morphine milligram equivalents) were collected. Analysis was done by comparing IT (n = 110) to a conventional TKA cohort (n = 217). When accounting for demographic differences and the use of a tourniquet, the IT cohort had shorter surgical time (88.77 ± 18.57 vs. 98.12 ± 22.53 minutes; p = 0.005). While postoperative day 1 pain scores were similar (p = 0.316), the IT cohort has less opioid consumption at 2 weeks (p = 0.006) and 1 month (p = 0.005) postoperatively, but not at 3 months (p = 0.058). When comparing different types of IT, CAN, and RA, we found that they had similar surgical times (p = 0.610) and pain scores (p = 0.813). Both cohorts had similar opioid consumption at 2 weeks (p = 0.092), 1 month (p = 0.058), and 3 months (p = 0.064) postoperatively. The use of IT in TKA does not yield a clinically significant reduction in pain outcomes. There was also no difference in pain or perioperative outcomes between CAN and RA technology used in TKA.

The impact of posterior-stabilized vs. constrained polyethylene liners in revision total knee arthroplasty

AIM

Posterior stabilized (PS) and varus valgus constrained (VVC) knee polyethylene liners have been shown to confer excellent long-term functional results following revision total knee arthroplasty (rTKA). The purpose of this study was to compare outcomes of patients who underwent rTKA using either a PS or VVC liner.

METHODS

A retrospective comparative study of 314 rTKA with either PS or VVC liner and a minimum follow-up time of two years was conducted. Patient demographics, complications, readmissions, and re-revision etiology and rates were compared between groups. Kaplan-Meier survivorship analysis was performed to estimate freedom from all-cause revision.

RESULTS

Hospital LOS (3.41 ± 2.49 vs. 3.34 ± 1.93 days, p = 0.793) and discharge disposition (p = 0.418) did not significantly differ between groups. At a mean follow-up of 3.55 ± 1.60 years, the proportion of patients undergoing re-revision did not significantly differ (19.1% vs. 18.7%, p = 0.929). In subgroup analysis of re-revision causes, the VVC cohort had superior survival from re-revision due to instability compared to the PS cohort (97.8% vs. 89.4%, p = 0.003). Freedom from re-revision due to aseptic loosening did not significantly differ between groups (85.2% vs. 78.8%, p = 0.436). Improvements in range of motion (ROM) from preoperative to latest follow-up were similar as well.

CONCLUSIONS

PS and VVC liners confer similar survivorship, complication rates, and overall knee ROM in rTKA. VVC liners were not associated with increased postoperative aseptic loosening and demonstrated superior freedom from re-revision due to instability. Future studies with longer follow-up are warranted to better determine significant differences in clinical outcomes between the two bearing options.

LEVEL III EVIDENCE

Retrospective Cohort Study.

Effect of Pelvic Sagittal Tilt and Axial Rotation on Functional Acetabular Orientation

Accurate and reproducible acetabular component positioning is among the most important technical factors affecting outcomes of total hip arthroplasty. Although several studies have investigated the influence of pelvic tilt and obliquity on functional acetabular anteversion, the effect of pelvic axial rotation has not yet been established. We analyzed a generic simulated pelvis created using preoperative full-body standing and sitting radiographs. A virtual acetabulum was placed in 144 different scenarios of acetabular anteversion and abduction angles. In each scenario, the effects of pelvic tilt and pelvic axial rotation on different combinations of acetabular orientations were assessed. The change in acetabular anteversion was 0.75° for each 1° of pelvic tilt and was most linear in abduction angles of 40°±45°. The change in acetabular anteversion was 0.8° for each 1° of pelvic axial rotation. Surgeons may consider adjusting acetabular anteversion in fixed axial pelvic deformities when the degree of deformity affects functional acetabular positioning, assessed from preoperative standing and sitting weight-bearing radiographs. [Orthopedics. 2023;46(1):e27-e30.].

Comparison of traditional PS versus kinematically designs in primary total knee arthroplasty

PURPOSE

Kinematically designed total knee arthroplasty (TKA) aims to restore normal kinematics by replicating the function of both cruciate ligaments. Traditional posterior-stabilized (PS) TKA designs, on the other hand, simplify knee kinematics and may improve TKA cost-effectiveness. The purpose of this study was to compare outcomes of patients who underwent primary TKA using either a traditional PS or kinematically designed TKA.

METHODS

This retrospective study examined all patients who underwent primary TKA using either a kinematically or a traditional PS designed TKA implant, with a minimum follow-up of 2 years. Patient demographics, complications, readmissions, revision rates and causes, range of motion (ROM) and patient reported outcomes (KOOS, JR) were compared between groups. Kaplan-Meier survivorship analysis was performed to estimate freedom from revision, and multivariate regression was performed to control for confounding variables.

RESULTS

A total of 396 TKAs [173 (43.7%) with a kinematic design, 223 (56.3%) with a traditional design] with a mean follow-up of 3.48 ± 1.51 years underwent analysis. Revision rates did not differ between groups (9.8% vs. 6.7%, p = 0.418). In Kaplan-Meier analysis at 2-year follow-up, freedom from all-cause revision (96.4% vs. 93.1%, p = 0.139) were similar between groups. The two cohorts had no significant difference in aseptic loosening at 2 years (99.6% vs. 97.1, p = 0.050) and at latest follow up (92.7% vs. 96.4%, p = 0.279). KOOS, JR scores and post-operative ROM were similar between groups.

CONCLUSION

This study demonstrated similar mid-term outcomes following the use of both a kinematically designed and a traditionally designed implant in primary TKA patients.

LEVEL OF EVIDENCE

Retrospective study-III.

Innovation for Orthopaedic Surgeons

Entrepreneurship and innovation are cornerstones of the economy and move healthcare forward. Most physicians have little experience or knowledge in developing and commercializing novel concepts and ideas. It is important to focus on structured thinking concepts, fundraising, intellectual property, FDA regulations, and initial incorporation and teambuilding strategies. There are various aspects of creating ideas and moving them from notes scribbled on a napkin to a product or service, which can then be integrated into the economic fabric of the healthcare system. Surgeon founders and innovators can then share key aspects any surgeon should consider when becoming an entrepreneur.

Prior Instability is Strongly Associated With Dislocation After Isolated Head and Liner Exchange

BACKGROUND

Isolated head and liner exchange is an appealing alternative to a more extensive revision total hip arthroplasty in patients who have well-fixed components. Despite efforts to increase femoral offset and restore soft tissue tensioning, limited component revision may be associated with higher rates of postoperative instability.

METHODS

This retrospective analysis assessed 209 patients who had a head and liner exchange conducted at a large academic medical center between 2011 and 2019 and had >2 years of follow-up. Functional cup positioning within the Lewinnek safe zone was assessed on postoperative weight-bearing radiographs. Included patients were 56% women, had a mean age of 64 years (range, 24-89) and a mean body mass index of 28.8 kg/m² (range, 18.2-46.7). The most common indications for surgery included acetabular liner wear in 86 hips (41%), instability in 40 hips (19%), and infection in 36 hips (17%).

RESULTS

Twenty-eight hips (13%) had a dislocation within 2 years after surgery. The best-fit model predicting postoperative dislocation included a history of dislocation (adjusted-odds ratio [adj-OR] 5.67, 95% CI 2.39-14.09, P < .001), age (adj-OR 1.04 per 1-year increase, 95% CI 0.99-1.08, P = .10), and body mass index (adj-OR 0.90 per 1-kg/m² increase, 95% CI 0.80-0.99, P = .046).

CONCLUSION

In a large cohort of patients who had isolated head and liner exchange, patients who had prior instability had 7-fold elevated odds of postoperative dislocation. This risk remains significant after controlling for cup positioning outside the Lewinnek safe zone, liner type, head size, neck length, soft tissue compromise, neuromuscular disease, and dual mobility constructs.

LEVEL OF EVIDENCE

III, retrospective cohort study.

The accuracy of component positioning during revision total hip arthroplasty using 3D optical computer-assisted navigation

INTRODUCTION

Despite the excellent outcomes associated with primary total hip arthroplasty (THA), implant failure and revision continue to burden the healthcare system. The use of computer-assisted navigation (CAN) offers the potential for more accurate placement of hip components during surgery. While intraoperative CAN systems have been shown to improve outcomes in primary THA, their use in the context of revision total hip arthroplasty (rTHA) has not been elucidated. We sought to investigate the validity of using CAN during rTHA.

METHODS

A retrospective analysis was performed at an academic medical institution identifying all patients who underwent rTHA using CAN from 2016-2019. Patients were 1:1 matched with patients undergoing rTHA without CAN (control) based on demographic data. Cup anteversion, inclination, change in leg length discrepancy (ΔLLD) and change in femoral offset between pre- and post-operative plain weight-bearing radiographic images were measured and compared between both groups. A safety target zone of 15-25° for anteversion and 30-50° for inclination was used as a reference for precision analysis of cup position.

RESULTS

Eighty-four patients were included: 42 CAN cases and 42 control cases. CAN cases displayed a lower ΔLLD (5.74 ± 7.0 mm vs 9.13 ± 7.9 mm, p = 0.04) and greater anteversion (23.4 ± 8.53° vs 19.76 ± 8.36°, p = 0.0468). There was no statistical difference between the proportion of CAN or control cases that fell within the target safe zone (40% vs 20.9%, p =  0.06). Femoral offset was similar in CAN and control cases (7.63 ± 5.84 mm vs 7.14 ± 4.8 mm, p = 0.68).

CONCLUSION

Our findings suggest that the use of CAN may improve accuracy in cup placement compared to conventional methodology, but our numbers are underpowered to show a statistical difference. However, with a ΔLLD of ~ 3.4 mm, CAN may be useful in facilitating the successful restoration of pre-operative leg length following rTHA. Therefore, CAN may be a helpful tool for orthopedic surgeons to assist in cup placement and LLD during complex revision cases.

Machine Learning With Electronic Health Record Data Outperforms a Risk Assessment Prediction Tool in Predicting Discharge Disposition After Total Joint Arthroplasty

The Risk Assessment Prediction Tool (RAPT) predicts discharge disposition after total joint arthroplasty with only 75% accuracy. The goal of this study was to evaluate whether higher accuracy can be achieved with basic electronic health record (EHR) data combined with machine learning (ML) algorithms. Three ML analysis models were developed: model 1 (M1) evaluated the accuracy of predicted discharge disposition in concordance with the RAPT; model 2 (M2) used the RAPT questionnaire to develop an ML algorithm to predict the likelihood of discharge to home vs facility; and model 3 (M3) was developed with non-RAPT data (age, surgeon, and discharge preference) with the same ML training process as M2. Evaluation metrics included accuracy for home discharge (HD), positive predictive value for HD (PPV-HD), negative predictive value for HD (NPV-HD), sensitivity, specificity, and area under the receiver operating curve (AUROC). A total of 1405 patients were included. With M1, the overall accuracy for HD was 83.5%, PPVHD was 92.1%, NPV-HD was 45%, sensitivity was 0.88, and specificity was 0.56. With M2, the overall accuracy for HD decreased to 82.8%, PPV-HD was 91.7%, NPV-HD was 43.1%, sensitivity was 0.87, specificity was 0.53, and mean AUROC was 0.87±0.03. With M3, overall accuracy for HD increased to 90.3%, PPV-HD was 95.2%, NPV-HD was 68.6%, sensitivity was 0.93, specificity was 0.76, and AUROC was 0.91±0.02. The use of basic EHR data combined with ML can exceed the accuracy of the RAPT. Applying big data on an individual level for this purpose may allow for safer and more appropriate discharge planning. [Orthopedics. 2022;45(4):e211-e215.].

Discontinued Use of Outpatient Portable Intermittent Pneumatic Compression Devices May Be Safe for Venous Thromboembolism Prophylaxis in Primary Total Knee Arthroplasty Using Low-Dose Aspirin

Venous thromboembolism (VTE) is a rare, but serious complication following total knee arthroplasty (TKA). Current VTE guidelines recommend pharmacologic agents with or without intermittent pneumatic compression devices (IPCDs). At our institution, both 81-mg aspirin (ASA) twice a day (BID) and portable IPCDs were previously prescribed to TKA patients at standard risk for VTE, but the IPCDs were discontinued and patients were treated with ASA alone going forward. The aim of this study is to determine if discontinued use of outpatient IPCDs is safe and does not increase the rate of VTE or any other related complications in patients following TKA. A retrospective review of 2,219 consecutive TKA cases was conducted, identifying patients with VTE, bleeding complications, infection, and mortality within 90 days postoperatively. Patients were divided into two cohorts. Patients in cohort one received outpatient IPCDs for a period of 14 days (control), while those in cohort two did not (ASA alone). All study patients received inpatient IPCDs and were maintained on 81-mg ASA BID for 28 days. A posthoc power analysis was performed using a noninferiority margin of 0.25 (α = 0.05; power = 80%), which showed that our sample size was fully powered for noninferiority for our reported deep vein thrombosis (DVT) rates, but not for pulmonary embolism (PE) rates. A total of 867 controls and 1,352 patients treated with ASA alone were identified. Only two control patients were diagnosed with a PE (0.23%), while one patient in the ASA alone group had DVT (0.07%). There was no statistical difference between these rates (p = 0.33). Furthermore, no differences were found in bleeding complications (p = 0.12), infection (p = 0.97), or 90-day mortality rates (p = 0.42) between both groups. The discontinued use of outpatient portable IPCDs is noninferior to outpatient IPCD use for DVT prophylaxis. Our findings suggest that this protocol change may be safe and does not increase the rate of VTE in standard risk patients undergoing TKA while using 81-mg ASA BID.

The effects of tourniquet on cement penetration in total knee arthroplasty

PURPOSE

Aseptic loosening is a common cause of implant failure following total knee arthroplasty (TKA). Cement penetration depth is a known factor that determines an implant's "strength" and plays an important role in preventing aseptic loosening. Tourniquet use is thought to facilitate cement penetration, but its use has mixed reviews. The aim of this study was to compare cement penetration depth between tourniquet and tourniquet-less TKA patients.

METHODS

A multicenter retrospective review was conducted. Patients were randomized preoperatively to undergo TKA with or without the use of an intraoperative tourniquet. The variables collected were cement penetration measurements in millimeters (mm) within a 1-month post-operative period, length of stay (LOS), and baseline demographics. Measurements were taken by two independent raters and made in accordance to the zones described by the Knee Society Radiographic Evaluation System and methodology used in previous studies.

RESULTS

A total of 357 TKA patients were studied. No demographic differences were found between tourniquet (n = 189) and tourniquet-less (n = 168) cohorts. However, the tourniquet cohort had statistically, but not clinically, greater average cement penetration depth [2.4 ± 0.6 mm (range 1.2-4.1 mm) vs. 2.2 ± 0.5 mm (range 1.0-4.3 mm, p = 0.01)]. Moreover, the tourniquet cohort had a significantly greater proportion of patients with an average penetration depth within the accepted zone of 2 mm or greater (78.9% vs. 67.3%, p = 0.02).

CONCLUSION

Tourniquet use does not affect average penetration depth but increases the likelihood of achieving optimal cement penetration depth. Further study is warranted to determine whether this increased likelihood of optimal cement penetration depth yields lower revision rates.

Outcomes of isolated head-liner exchange versus full acetabular component revision in aseptic revision total hip arthroplasty

INTRODUCTION

Isolated head and liner exchange in aseptic revision total hip arthroplasty (rTHA) is an appealing option rather than full acetabular component revision; however, early outcome reports suggest high rates of complications requiring re-revision. This study seeks to compare the outcomes of these procedures.

METHODS

This retrospective study assessed 124 head and liner exchanges and 59 full acetabular cup revisions conducted at a single center between 2011 and 2019 with at least 2 years of follow-up. Baseline demographics did not vary by group. Mean follow-up was 3.7 (range 2.0-8.6) years.

RESULTS

In the head and liner exchange group, re-revision-free survivorship at 2 years was 79% for all-causes and 84% for aseptic reasons. In the full acetabular revision group, it was 80% for all causes (p > 0.99) and 83% for aseptic reasons (p > 0.99). The 2-year survivorship of head and liner exchange was non-inferior to that of full acetabular revision, correcting for surgical indication and history of prior revision (adj-OR 0.1.39, 95% CI, 0.62-3.28, p = 0.99). A best-fit multivariable model found that revision for instability (adj-OR=3.03, 95% CI 1.40-6.66, p = 0.005), prior revision (adj-OR 2.15; 95% CI, 0.87-5.32; p = 0.10), current smoking (adj-OR 2.07; 95% CI, 0.94-4.57; p = 0.07), and obesity (adj-OR 0.58; 95% CI, 0.24-1.36; p = 0.22) were associated with failure within 2 years.

CONCLUSIONS

In this analysis, 2-year outcomes for isolated head and liner exchange were non-inferior to full acetabular component revision. A future randomised prospective study should be conducted to better assess the optimal approach to revision in an aseptic failed hip arthroplasty.

The use of imageless navigation to quantify cutting error in total knee arthroplasty

PURPOSE

Navigated total knee arthroplasty (TKA) improves implant alignment by providing feedback on resection parameters based on femoral and tibial cutting guide positions. However, saw blade thickness, deflection, and cutting guide motion may lead to final bone cuts differing from planned resections, potentially contributing to suboptimal component alignment. We used an imageless navigation device to intraoperatively quantify the magnitude of error between planned and actual resections, hypothesizing final bone cuts will differ from planned alignment.

MATERIALS AND METHODS

A retrospective study including 60 consecutive patients undergoing primary TKA using a novel imageless navigation device was conducted. Device measurements of resection parameters were obtained via attachment of optical trackers to femoral and tibial cutting guides prior to resection. Following resection, optical trackers were placed directly on the bone cut surface and measurements were recorded. Cutting guide and bone resection measurements of both femoral and tibial varus/valgus, femoral flexion, tibial slope angles, and both femoral and tibial medial and lateral resection depths were compared using a Student's t-test.

RESULTS

Femoral cutting guide position differed from the actual cut by an average 0.6 ± 0.5° (p = 0.85) in the varus/valgus angle and 1.0 ± 1.0° (p = 0.003) in the flexion/extension angle. The difference between planned and actual cut measurements for medial and lateral femoral resection depth was 1.1 ± 1.1 mm (p = 0.32) and 1.2 ± 1.0 mm (p = 0.067), respectively. Planned cut measurements based on tibial guide position differed from the actual cut by an average of 0.9 ± 0.8° (p = 0.63) in the varus/valgus angle and 1.1 ± 1.0° (p = 0.95) in slope angle. Measurement of medial and lateral tibial resection depth differed by an average of 0.1 ± 1.8 mm (p = 0.78) and 0.2 ± 2.1 mm (p = 0.85), respectively.

CONCLUSIONS

Significant discrepancies between planned and actual femoral bone resection were demonstrated for flexion/extension angle, likely the result of cutting error. Our data highlights the importance of cut verification postresection to confirm planned resections are achieved, and suggests imageless navigation may be a source of feedback that would allow surgeons to intraoperatively adjust resections to achieve optimal implant alignment.

Impact of Preoperative Opioid Use on Patient Outcomes Following Primary Total Hip Arthroplasty

The purpose of this study was to investigate whether preoperative opioid use had any effect on clinical outcomes and patient-reported outcome measures (PROMs) before and after primary, elective total hip arthroplasty (THA). The authors retrospectively reviewed 793 patients who underwent primary THA from November 2018 to March 2020 with available PROMs. Patients were stratified into two groups based on whether or not they were taking opioids preoperatively. Demographics, clinical data, and PROMs (Forgotten Joint Score-12 [FJS-12], Hip disability and Osteoarthritis Outcome Score for Joint Replacement [HOOS, JR], and Veterans RAND 12 [VR-12] Physical Component Score [PCS] and Mental Component Score [MCS]) were collected at various time periods. Demographic differences were assessed with chi-square and independent sample t tests. Clinical data and PROMs were compared using multilinear regressions. Seventy-five (10%) patients were preoperative opioid users and 718 (90%) were not. Preoperative opioid users had a longer stay (1.37 vs 1.07 days; P=.030), a longer surgical time (102.44 vs 90.20 minutes; P=.001), and higher all-cause postoperative emergency department visits (6.7% vs 2.1%; P=.033) compared with patients not taking opioids preoperatively. Preoperative HOOS, JR (46.63 vs 51.26; P=.009), VR-12 PCS (27.79 vs 31.53; P<.001), and VR-12 MCS (46.24 vs 49.33; P=.044) were significantly lower for preoperative opioid users, but 3-month and 1-year postoperative scores were not statistically different. At 3 months and 1 year, FJS-12 scores did not differ significantly. Mean improvement preoperatively to 1 year in HOOS, JR values exceeded the minimal clinically important difference, with preoperative opioid users experiencing a greater improvement (36.50 vs 33.11; P=.008). Preoperative opioid users had a longer stay, a longer surgical time, and higher all-cause emergency department visits compared with preoperatively opioid naïve patients. Although preoperative opioid users reported significantly lower preoperative PROMs, they did not statistically differ postoperatively, which indicates a larger delta improvement and similar benefits following THA. [Orthopedics. 2021;44(2):77-84.].

Primary total hip arthroplasty outcomes in octogenarians

Aims

As our population ages, the number of octogenarians who will require a total hip arthroplasty (THA) rises. In a value-based system where operative outcomes are linked to hospital payments, it is necessary to assess the outcomes in this population. The purpose of this study was to compare outcomes of elective, primary THA in patients ≥ 80 years old to those aged < 80.

Methods

A retrospective review of 10,251 consecutive THA cases from 2011 to 2019 was conducted. Patient-reported outcome (PRO) scores (Hip disability and Osteoarthritis Outcome Score (HOOS)), as well as demographic, readmission, and complication data, were collected.

Results

On average, the younger cohort (YC, n = 10,251) was a mean 61.60 years old (SD 10.71), while the older cohort (OC, n = 609) was 84.25 years old (SD 3.02) (p < 0.001). The OC had greater surgical risk based on their higher mean American Society of Anesthesiologists (ASA) scores (2.74 (SD 0.63) vs 2.30 (SD 0.63); p < 0.001) and Charlson Comorbidity Index (CCI) scores (6.26 (SD 1.71) vs 3.87 (SD 1.98); p < 0.001). While the OC stayed in the hospital longer than the YC (mean 3.5 vs 2.5 days; p < 0.001), there were no differences in 90-day emergency visits (p = 0.083), myocardial infarctions (p = 0.993), periprosthetic joint infections (p = 0.214), dislocations (p = 0.993), or aseptic failure (p = 0.993). The YC was more likely to be readmitted within 90 days (3.88% vs 2.18%, Β = 0.57; p = 0.048). There were no observed differences in 12-week (p = 0.518) or one-year (p = 0.511) HOOS scores.

Conclusion

Although patients ≥ 80 years old have a greater number of comorbidities than younger patients, they had equivalent perioperative complication rates and PRO scores. This study demonstrates the safety and success of elective THA in octogenarians.

Cite this article: Bone Jt Open 2021;2(7):535–539.

Does the Use of a Tourniquet Influence Outcomes in Total Knee Arthroplasty: A Randomized Controlled Trial

BACKGROUND

Intraoperative tourniquet use in total knee arthroplasty (TKA) is a common practice which may improve visualization of the surgical field and reduce blood loss. However, the safety and efficacy associated with tourniquet use continues to be a subject of debate among orthopedic surgeons. The primary purpose of this study is to evaluate the effects of tourniquet use on pain and opioid consumption after TKA.

METHODS

This is a multicenter randomized controlled trial among patients undergoing TKA. Patients were preoperatively randomized to undergo TKA with or without the use of an intraoperative tourniquet. Frequency distributions, means, and standard deviations were used to describe baseline patient demographics (age, gender, race, body mass index, smoking status), length of stay, surgical factors, visual analog scale pain scores, and opioid consumption in morphine milligram equivalents.

RESULTS

A total of 327 patients were included in this study, with 166 patients undergoing TKA without a tourniquet and 161 patients with a tourniquet. A statistically significant difference was found in surgical time (97.87 vs 92.98 minutes; P = .05), whereas none was found for length of stay (1.73 vs 1.70 days; P = .87), postop visual analog scale pain scores (1.73 vs 1.70; P = .87), inpatient opioid consumption (19.84 vs 19.27 morphine milligram equivalents; P = .74), or outpatient opioid consumption between the tourniquet-less and tourniquet cohorts, respectively. There were no readmissions in either cohort during the 90-day episode of care.

CONCLUSION

Utilization of a tourniquet during TKA has minimal impact on postoperative pain scores and opioid consumption when compared with patients who underwent TKA without a tourniquet.

Adoption of Robotic Arm-Assisted Total Hip Arthroplasty Results in Reliable Clinical and Radiographic Outcomes at Minimum Two-Year Follow Up

INTRODUCTION

Longevity and success of total hip arthroplasty (THA) is largely dependent on component positioning. While use of robotic platforms can improve this positioning, published evidence on its clinical benefits is limited. Therefore, the aim of this study was to assess the clinical outcomes of THA with robotic surgical assistance.

MATERIALS AND METHODS

We conducted an analysis of robotic arm-assisted primary THAs performed by a single surgeon utilizing a posterior approach. A total of 99 patients (107 cases) who had a minimum two-year follow up were identified. Their mean age was 61 years (range, 33 to 84 years), and their mean body mass index was 30.5 kg/m2 (range, 18.5 to 49.1 kg/m2). There were 56% female patients and primary osteoarthritis was the principal hip diagnosis in 88.8%. Operative times, lengths of hospital stay, and discharge dispositions were recorded, along with any complications. Modified Harris Hip Scores (HHS) were calculated to quantify clinical outcomes.

RESULTS

Mean postoperative increases in HHS at 2- to 5.7-year follow up was 33 points (range, 6 to 77 points). There were no complications attributable to the use of robotic assistance. Surgical-site complications were rare; one case underwent a revision for prosthetic joint infection (0.93%) but there were no dislocations, periprosthetic fractures, or cases of mechanical implant loosening. There was no evidence of progressive radiolucencies or radiographic failure.

DISCUSSION

Robotic arm-assisted THA resulted in low complication rates at minimum two-year follow up, with clinical outcomes comparable to those reported with manual surgery.1-4 The haptically-guided acetabular bone preparation enabled reliable cementless acetabular fixation and there were no adverse events related to the use of the robot. Dislocations were avoided in this case series. Randomized controlled clinical trials are needed to compare manual to robotic surgery and to investigate whether the precision found with this functional planning will reliably reduce the incidence of dislocations.

Total Hip Arthroplasty for Femoral Neck Fracture in the Setting of Challenging Extraction of an Intramedullary Femoral Nail: A Case Report

Introduction:

Performing total hip arthroplasty (THA) for femoral neck fracture in the setting of a pre-existing intramedullary nail can be technically challenging, particularly if nail extraction is not feasible.

Case Report:

A 76-year-old male presented with a with a displaced femoral neck fracture in the setting of a previously placed antegrade intramedullary nail with a healed femoral shaft fracture. After failed nail extraction, a novel technique was used to remove the proximal portion of the nail to allow for hybrid THA with implantation of a cemented femoral stem.

Conclusion:

This is the first reported surgical technique of using a cortical window technique for partial intramedullary nail resection and cemented stem implantation in the setting of challenging intramedullary femoral nail extraction.

Complex Regional Pain Syndrome Following Total Knee Arthroplasty

Complex regional pain syndrome (CRPS) is an uncommon cause of residual pain after total knee arthroplasty (TKA). The presentation is variable, and there is no gold standard diagnostic test. Diagnosis is more difficult after TKA because some classic signs of CRPS may be unreliable and imaging may be difficult to interpret. Early intervention is the most important factor in predicting improvement, necessitating high suspicion in patients with exaggerated pain and stiffness after excluding more common causes. This article reviews the literature regarding CRPS following TKA, explains the diagnosis, and discusses treatment. [Orthopedics. 2020;43(6):e486-e491.].

Use of a Modified Rep Model in Primary Joint Arthroplasty: Lessons Learned

Orthopedic implant device sales representatives ("reps") can provide intraoperative guidance based on their product knowledge, as part of their many responsibilities. However, for experienced high-volume arthroplasty surgeons, a representative may not be required in the room for most primary total knee arthroplasty (TKA) procedures. The goal of this study was to describe the authors' experience with a modified rep model for primary TKA. Between January and December 2017, a total of 100 unilateral primary TKAs were performed with a modified rep model and compared with 100 primary TKAs that were performed before this protocol. The authors adopted 2 additional initiatives to institute this protocol safely: (1) improved education of operating room staff and allocation of responsibilities; and (2) reengineering of the existing surgical trays. No perioperative complications, including readmission, periprosthetic fracture, or infection, occurred in either group. In addition, no difference was found in mean length of stay between the modified rep and conventional cohorts (2.2 and 2.4 days, respectively; P=.49). Mean operating room time was less with the modified rep cohort (102.1 vs 117.8 minutes; P<.001), as was total instrument turnover time in the operating room (13.9 vs 29.7 minutes; P<.0001) and in central sterilization (59.4 vs 126.8 minutes; P<.001). No errors occurred with implant accuracy or trays, and there was no need to change the type of implant with the modified rep model, compared with 6% of trays requiring additional sterilization with the conventional model. The negotiated implant cost with the modified rep model was approximately $2000 less than that for the conventional group. This study found that the modified rep model for primary TKA is safe and has the potential for substantial cost savings. [Orthopedics. 2020;43(6):e538-e542.].

Obesity does not influence acetabular component accuracy when using a 3D optical computer navigation system

INTRODUCTION

Improper cup positioning and leg length discrepancy (LLD) are two of the most common errors following total hip arthroplasty (THA) and are associated with potentially significant consequences. Obesity is associated with increased risk of mechanical complications, including dislocations, which may be secondary to cup malposition and failure to restore leg length and offset. 3D Optical Camera computerassisted navigation (CAN) system may reduce the risk of component malposition and LLD with real time intraoperative feedback. The aim of this study was to investigate whether the use of CAN influences acetabular component placement (CP) accuracy and leg length restoration in obese (body mass index(BMI)≥35kg/m 2 ) patients undergoing primary THA.

METHODS

A multi-center retrospective review was conducted identifying consecutive THA cases with BMI > 35kg/m 2 using CAN (Intellijoint Hip, Waterloo, CA) from 2015-2019. These patients were then matched with patients undergoing conventional THA (control) at a 1:1 ratio according to BMI, American Society of Anesthesiologists score, and gender. TraumaCad™ software (Brainlab, Chicago, IL) was used to measure cup anteversion, inclination, and change (Δ) in LLD between pre- and postoperative radiographic images. The safety target zones used as reference for precision analysis of CP were 15°-30° for anteversion and 30°-50° for inclination.

RESULTS

176 patients were included: 88 CAN and 88 control cases. CAN cases were found to have a lower ΔLLD than controls (3.53±2.12mm vs. 5.00±4.05mm; p=0.003). Additionally, more CAN cases fell within the target safe zone than controls (83% vs.60%, p=0.00083).

CONCLUSION

Our findings suggest that the use of a CAN system may be more precise in component placement, and useful in facilitating the successful restoration of preoperative leg length following THA than conventional methodology.

Transcription Error Rates in Retrospective Chart Reviews

Electronic health record (EHR) technologies have improved the ease of access to structured clinical data. The standard means by which data are collected continues to be manual chart review. The authors compared the accuracy of manual chart review against modern electronic data warehouse queries. A manual chart review of the EHR was performed with medical record numbers and surgical admission dates for the 100 most recent inpatient venous thromboembolic events after total joint arthroplasty. A separate data query was performed with the authors' electronic data warehouse. Data sets were then algorithmically compared to check for matches. Discrepancies between data sets were evaluated to categorize errors as random vs systematic. From 100 unique patient encounters, 27 variables were retrieved. The average transcription error rate was 9.19% (SD, ±5.74%) per patient encounter and 11.04% (SD, ±21.40%) per data variable. The systematic error rate was 7.41% (2 of 27). When systematic errors were excluded, the random error rate was 5.79% (SD, ±7.04%) per patient encounter and 5.44% (SD, ±5.63%) per data variable. Total time and average time for manual data collection per patient were 915 minutes and 10.3±3.89 minutes, respectively. Data collection time for the entire electronic query was 58 seconds. With an error rate of 10%, manual chart review studies may be more prone to type I and II errors. Computer-based data queries can improve the speed, reliability, reproducibility, and scalability of data retrieval and allow hospitals to make more data-driven decisions. [Orthopedics. 2020;43(5):e404-e408.].

The effect of implant size difference on patient outcomes and failure after bilateral simultaneous total knee arthroplasty

Background

Proper sizing of femoral and tibial components has been associated with long-term outcomes and survivorship in simultaneous bilateral total knee arthroplasty (SBTKA) and may be a reason for differences in outcomes between knees. The aim of this study compares post-operative outcomes and revision rates in patients undergoing SBTKA with different component sizes.

Methods

A retrospective review was conducted at a single academic institution identifying patients who underwent SBTKA from 2011 to 2019. Inclusion criteria included: primary osteoarthritis, similar pre-operative deformity, and same implant manufacturer. The primary outcome compares pre- and post-op (delta, Δ) Knee Society Score-Knee Score (KSS-KS) and range of motion (ROM) between knees. Secondary outcome measures were all-cause revisions rates, including manipulations under anesthesia and arthroscopy with or without lysis of adhesions.

Results

149 patients were identified who met the inclusion criteria: 128 patients had femoral size difference (FSD) of 0, 138 patients had tibial size difference (TSD) of 0, 21 patients with FSD of 1, and 11 patients with TSD of 1. There was no difference in ΔKSS-KS or ΔROM in patients for any FSD or TSD. Revisions for aseptic loosening were greater for TSD 1 compared to TSD 0 (p < 0.001). No other differences in cause of revision were identified.

Conclusion

A TSD of 1 may be associated with increased revision rates for aseptic loosening in both smaller and larger sized implants. Surgeons may achieve optimal patient outcomes in SBTKA with proper sized implants through increased awareness of component asymmetry and repeat intraoperative evaluation when asymmetrical measurements occur.

Piriformis-Sparing Technique in Total Hip Arthroplasty with Posterolateral Approach

INTRODUCTION

Hip dislocation is a devastating complication after total hip arthroplasty (THA), which is slightly higher when using the traditional posterior approach. The piriformis tendon is the most important dynamic posterior stabilizing structure. The piriformis-sparing technique provides a reproducible method for THA, greatly reducing the dislocation rate.

MATERIALS AND METHODS

After exposure and identifying piriformis, the inferior border of the piriformis is released from the short rotators and capsule with a BOVIE® (Symmetry Surgical, Inc, Nashville, Tennessee). This dissection is continued to the lesser trochanter as one sleeve and then tagged. The anterior/inferior capsule is released with a BOVIE® from the femur to aid in acetabular exposure. The femur is roughly placed in 30° of adduction, 70° of flexion, and slight internal rotation. An anterior retractor is used to displace the proximal femur anteriorly and superiorly. The reamer is placed inside the acetabulum through the inferior approach. Next, the acetabulum is progressively reamed to the appropriate size and depth, and the final component is placed in proper anteversion and abduction angles based on preoperative functional assessment. After insertion of final components and final hip reduction, the interval beneath the piriformis tendon and superior portion of the capsule is repaired with ETHIBOND® sutures (Johnson & Johnson Inc., New Brunswick, New Jersey). Then, two tunnels in the proximal femur with a 2.7mm drill bit is made and posterior capsule and short rotators are secured through these tunnels.

RESULTS

This technique was used in 150 THAs with a minimum follow up of six months and a mean of 1.2 years ± 1.5 years. There was no dislocation at final follow up. The mean anteversion and abduction was 23 ± 2.7 and 42 ± 3.1, respectively.

CONCLUSION

Preserving the piriformis tendon may cause less visualization of the superior portion of the acetabulum. However, the anterior/inferior capsular release, and proper placement of the femur with flexion, internal rotation, and adduction, makes it possible to achieve highly reproducible results.

Customized Knee Articulating Cement Spacer with Stem Extension for Treatment of Chronic Periprosthetic Joint Infection

INTRODUCTION

Choice of articulating spacer in selected Methicillin-resistant Staphylococcus aureus (MRSA) patients with instability that do not qualify for a second-stage revision (i.e., due to significant co-morbidities, multiple persistent infections, open wound ulcers) is challenging. To avoid a recurrent biofilm when using a cruciate-retaining (Cr/Cb) femoral implant, we have utilized a polymer femoral implant and constraint all-polyethylene (all-poly) tibia with stem extensions as a permanent spacer.

MATERIALS AND METHODS

After removal of prior implants and final debridement, appropriate-sized trial femur and proper thickness all-poly tibia are selected. Two chest tubes are loaded with cement with a delivery gun to make the extension rods. A Steinmann pin is inserted into the stem of the tibial insert. The components are inserted and the knee is reduced, then flexion and extension gaps are assessed. Small adjustments can be made to fill the gaps with extra cement. If there is collateral insufficiency, a constrained polyethylene (poly) can be used with the extension rod. An appropriate antibiotic is used based on the final culture, sensitivity, and availability in powder form.

RESULTS

This technique has been performed on 32 MRSA prosthetic joint infection (PJI) cases, followed for a minimum of nine months (nine months to three years). The mean final range of motion was 70 ± 15 degrees (30-110 degrees). Final radiographs do not show any sign of subsidence, loosening, or failure of the spacer. Rate of eradication of infection was 97% in the remaining 31 cases. One patient required amputation due to lack of wound coverage.

CONCLUSION

Custom-made articulating spacer using all-poly tibia and a trial femur with stem extension can provide reproducible outcomes in treating PJI while maintaining mobility.

Efficacy of Adductor Canal Block With Liposomal Bupivacaine: A Randomized Prospective Clinical Trial

This study compared the postoperative analgesic efficacy of liposomal bupivacaine as a single-administration adductor canal block (ACB) vs periarticular injection (PAI) for pain control after total knee arthroplasty (TKA). From May 2016 to June 2017, a total of 70 unilateral TKA patients were randomized into 2 groups: PAI (extended-release bupivacaine 266 mg [20-mL vial] with 20 mL of 0.5% bupivacaine hydrochloride and normal saline to a total volume of 120 mL) and ACB (subsartorial saphenous nerve using extended-release bupivacaine 266 mg [20-mL vial]). All patents underwent spinal anesthesia with comprehensive preemptive and postoperative multi-modal pain protocol. All opioids administered were converted to morphine equivalents. Pain was recorded at 4 to 12 hours on the day of surgery, and on postoperative days 1, 2, and 3. Patients and investigators other than the surgeon and anesthesiologist were blinded to the study. The difference in pain scores between the PAI and ACB groups was not statistically significant during the first 12 hours (day 0) after surgery or on postoperative day 1 (5.31 vs 4.26, P=.091). However, on postoperative day 3, the mean pain score increased in the ACB group and decreased in the PAI group (4.8 vs 1.83, P=.037). There was no statistically significant difference between the 2 groups regarding the accumulative daily converted morphine equivalent consumption or total consumption. Although the PAI group demonstrated longer lasting pain relief than the ACB group for the duration of the study, other outcomes were similar between the 2 groups. [Orthopedics. 2020; 43(1):e47-e53.].

Arthrofibrosis After Total Knee Arthroplasty: Pathophysiology, Diagnosis, and Management

Arthrofibrosis is the pathologic stiffening of a joint caused by an exaggerated inflammatory response. As a common complication following total knee arthroplasty (TKA), this benign-appearing connective tissue hyperplasia can cause significant disability among patients because the concomitant knee pain and restricted range of motion severely hinder postoperative rehabilitation, clinical outcomes, and basic activities of daily living. The most effective management for arthrofibrosis in the setting of TKA is prevention, including preoperative patient education programs, aggressive postoperative physical therapy regimens, and anti-inflammatory medications. Operative treatments include manipulation under anesthesia, arthroscopic debridement, and quadricepsplasty.

Tranexamic Acid Reduces Transfusion Rates in Obese Patients Undergoing Total Joint Arthroplasty

BACKGROUND

While tranexamic acid (TXA) has been well shown to reduce blood loss after joint replacement surgery, little is known regarding its effectiveness in obese patients. The aim of this study was to evaluate the effect of TXA changes in hematocrit and hemoglobin levels as well as incidence of packed red blood cell (pRBC) transfusions in obese patients undergoing total joint arthroplasty (TJA).

MATERIAL AND METHODS

Between January 2014 and May 2015, 420 consecutive primary joint replacements were performed by two surgeons at our institution. One-hundred-fifty-seven patients (total hip arthroplasty [THA]=29; total knee arthroplasty [TKA]=128) were obese with a body mass index (BMI) greater than or equal to 30 kg/m2. Medical records were reviewed and identified that TXA was utilized in 85 (54.1%) arthroplasties (study group) and was compared to a consecutive series of 72 (45.9%) TJAs (control group). TXA was given intravenously (IV) in two doses: (1) one gram prior to incision and (2) one gram at the time of femoral preparation in THA or prior to cementation in TKA. Changes in hemoglobin and hematocrit levels, number of pRBC transfusions, and occurrence of thrombolytic events were recorded.

RESULTS

The changes in hematocrit (7.2% vs. 8.1%) and hemoglobin levels (3.0 g/dl vs. 3.3 g/dl) were less in the group that received TXA than the control group, albeit not significantly (p=0.100 and p=0.278, respectively). Within the control group, 26 (36.1%) patients required a pRBC transfusion with a mean of 2.0 units per patient (range:1-5); whereas, only eight (9.4%) patients with TXA required a mean of 1.6 units per patient (range: 1-2). The use of TXA significantly reduced the incidence of pRBC transfusions, especially in TKA (p<0.001). Sub-analyses revealed that transfusion rates were even more significantly reduced by TXA in obesity type II and III. Two pulmonary emboli were reported in the group that did not receive TXA; whereas, no thrombolytic events were reported in the group that did receive TXA.

CONCLUSION

Utilization of TXA significantly reduced the rate of pRBC transfusions in obese patients.