Shedding Light on the Effects of Blood on Meniscus Tissue: The Role of Mononuclear Leukocytes in Mediating Meniscus Catabolism

OBJECTIVE

Traumatic meniscal injuries can cause acute pain, hemarthrosis (bleeding into the joint), joint immobility, and post-traumatic osteoarthritis (PTOA). However, the exact mechanism(s) by which PTOA develops following meniscal injuries is unknown. Since meniscus tears commonly coincide with hemarthrosis, investigating the direct effects of blood and its constituents on meniscus tissue is warranted. The goal of this study was to determine the direct effects of blood and blood components on meniscus tissue catabolism.

METHODS

Porcine meniscus explants or primary meniscus cells were exposed to whole blood or various fractions of blood for 3 days to simulate blood exposure following injury. Explants were then washed and cultured for an additional 3 days prior to collection for biochemical analyses.

RESULTS

Whole blood increased matrix metalloproteinase (MMP) activity. Fractionation experiments revealed blood-derived red blood cells (RBCs) did not affect meniscus catabolism. Conversely, viable mononuclear leukocytes induced MMP activity and nitric oxide (NO) production and loss of tissue sulfated glycosaminoglycan (sGAG) content, suggesting that these cells are mediating meniscus catabolism.

CONCLUSIONS

These findings highlight the potential challenges of meniscus healing in the presence of hemarthrosis and the need for further research to elucidate the in vivo effects of blood and blood-derived mononuclear leukocytes due to both hemarthrosis and blood-derived therapeutics.

A modified Delphi consensus statement on patellar instability: part II

Aims

The aim of this study was to establish consensus statements on medial patellofemoral ligament (MPFL) reconstruction, anteromedialization tibial tubercle osteotomy, trochleoplasty, and rehabilitation and return to sporting activity in patients with patellar instability, using the modified Delphi process.

Methods

This was the second part of a study dealing with these aspects of management in these patients. As in part I, a total of 60 surgeons from 11 countries contributed to the development of consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest. Consensus was defined as achieving between 80% and 89% agreement, strong consensus was defined as between 90% and 99% agreement, and 100% agreement was considered unanimous.

Results

Of 41 questions and statements on patellar instability, none achieved unanimous consensus, 19 achieved strong consensus, 15 achieved consensus, and seven did not achieve consensus.

Conclusion

Most statements reached some degree of consensus, without any achieving unanimous consensus. There was no consensus on the use of anchors in MPFL reconstruction, and the order of fixation of the graft (patella first versus femur first). There was also no consensus on the indications for trochleoplasty or its effect on the viability of the cartilage after elevation of the osteochondral flap. There was also no consensus on postoperative immobilization or weightbearing, or whether paediatric patients should avoid an early return to sport.

A modified Delphi consensus statement on patellar instability: part I

Aims

The aim of this study was to establish consensus statements on the diagnosis, nonoperative management, and indications, if any, for medial patellofemoral complex (MPFC) repair in patients with patellar instability, using the modified Delphi approach.

Methods

A total of 60 surgeons from 11 countries were invited to develop consensus statements based on their expertise in this area. They were assigned to one of seven working groups defined by subtopics of interest within patellar instability. Consensus was defined as achieving between 80% and 89% agreement, strong consensus was defined as between 90% and 99% agreement, and 100% agreement was considered to be unanimous.

Results

Of 27 questions and statements on patellar instability, three achieved unanimous consensus, 14 achieved strong consensus, five achieved consensus, and five did not achieve consensus.

Conclusion

The statements that reached unanimous consensus were that an assessment of physeal status is critical for paediatric patients with patellar instability. There was also unanimous consensus on early mobilization and resistance training following nonoperative management once there is no apprehension. The statements that did not achieve consensus were on the importance of immobilization of the knee, the use of orthobiologics in nonoperative management, the indications for MPFC repair, and whether a vastus medialis oblique advancement should be performed.

Early clinical and patient-reported outcomes for arthroscopic and mini-open superior capsular reconstruction are similar for irreparable rotator cuff tears

OBJECTIVES

The purpose of this study was to report and compare postoperative range of motion (ROM), patient-reported outcomes, and failure rates following superior capsular reconstruction (SCR) and to compare outcomes between arthroscopic and mini-open techniques.

METHODS

All SCR procedures utilising dermal allograft with a minimum of 6 months of follow-up at multiple institutions between November 2015 and October 2019 were retrospectively reviewed. Preoperative patient demographics, imaging measurements, surgical technique (arthroscopic versus mini-open), and outcomes including pain scores, conversion to reverse shoulder arthroplasty, subsequent surgery, and postoperative ROM were recorded. Outcomes for arthroscopic versus mini-open approaches were compared via t-test, Fisher's exact test, or chi square test, as appropriate, with differences of p ​< ​0.05 considered significant.

RESULTS

180 total patients were included, including 98 who underwent arthroscopic SCR and 82 who underwent mini-open SCR. Final follow-up was at a mean of 32 months (standard deviation = 11 months). SCR improved pain (visual analog scale ​= ​4.4 pre-operatively vs. 1.4 post-operatively, p ​< ​0.0001) and ROMin active forward flexion (136° pre-operatively vs. 150° post-operatively, p ​= ​0.0012). No difference in post-operative pain visual analog scores was found between mini-open and arthroscopic cohorts (1.3 vs. 1.6, p ​= ​0.3432) at a mean of 14 months post-operatively. At a mean of 32 months post-operatively, there were no differences in ASES, QuickDASH, SST, WORC, or SANE scores between open and arthroscopic cohorts. There was no difference in rates of failure between mini-open and arthroscopic cohorts (15.9% vs. 17.3%, p ​= ​0.789).

CONCLUSIONS

This study confirmed that SCR improves pain and ROM in the short term. Mini-open SCR appears to provide similar improvements in pain and ROM compared with arthroscopic SCR, as well as patient-reported outcomes at 3 years. No difference in failure rates was detected between the 2 procedures.

LEVEL OF EVIDENCE

Level 3 evidence.

Achilles Tendon Injuries in the Pediatric Population

BACKGROUND

Achilles tendon injuries are common in adults, and there is extensive literature describing the injury characteristics and treatment of these adult injuries. However, Achilles injuries are rare in the pediatric population and as a result, there is limited research reported on this age group. We therefore sought to characterize the injury presentation, treatment and outcomes for pediatric patients with partial and complete Achilles injuries.

METHODS

A retrospective chart review was conducted of patients aged 0-18 treated for Achilles tendon injuries at 2 geographically distinct tertiary institutions between 2008 and 2021. Data collected included demographics, injury characteristics, and treatment course. Injury types were separated into 2 cohorts: traumatic Achilles injuries and ruptures due to muscular contraction. Traumatic injuries were further delineated into 2 injury mechanisms: open injuries related to penetrating trauma and closed injuries related to blunt trauma. Standard descriptive analyses were utilized to summarize findings.

RESULTS

Thirty-nine patients (43.6% female, median age 15 years) were identified, 29 (74.4%) of whom had complete tears. Twenty-five patients (64.1%) presented with traumatic injuries; among these, 48.0% (n=12/25) were ≤12 years. All patients ≤12 years sustained a traumatic injury. The most common traumatic mechanism was an open laceration due to penetrating trauma (68.0%), followed by closed ruptures associated with blunt trauma (32.0%). Fourteen patients (35.9%) presented with closed ruptures due to muscular contraction. Four patients (10.2%) had a prior history of clubfoot treated with Achilles tenotomy. Thirty-five patients (89.7%) were surgically treated with an open repair. The median immobilization period across all patients was 11 weeks (interquartile range: 10-12), starting most commonly with a posterior splint (46.2%) and concluding with a CAM boot (94.9%). Of patients with full follow-up data (n=22/39), all resumed normal activities, with a median clearance time of 6 months (interquartile range: 5-7.9).

CONCLUSIONS

We found that older adolescents (≥14 y) were more likely to rupture their Achilles tendon through a forceful muscular contraction, whereas younger patients (≤12 y) were more likely to injure their Achilles via a traumatic mechanism. Most patients were treated operatively and returned to sports at a median time of 6 months. A further prospective study is warranted to better characterize treatment protocols and patient outcomes in this population.

LEVEL OF EVIDENCE

Level-IV.

The Interplay of Biomechanical and Biological Changes Following Meniscus Injury

PURPOSE OF REVIEW

Meniscus injury often leads to joint degeneration and post-traumatic osteoarthritis (PTOA) development. Therefore, the purpose of this review is to outline the current understanding of biomechanical and biological repercussions following meniscus injury and how these changes impact meniscus repair and PTOA development. Moreover, we identify key gaps in knowledge that must be further investigated to improve meniscus healing and prevent PTOA.

RECENT FINDINGS

Following meniscus injury, both biomechanical and biological alterations frequently occur in multiple tissues in the joint. Biomechanically, meniscus tears compromise the ability of the meniscus to transfer load in the joint, making the cartilage more vulnerable to increased strain. Biologically, the post-injury environment is often characterized by an increase in pro-inflammatory cytokines, catabolic enzymes, and immune cells. These multi-faceted changes have a significant interplay and result in an environment that opposes tissue repair and contributes to PTOA development. Additionally, degenerative changes associated with OA may cause a feedback cycle, negatively impacting the healing capacity of the meniscus. Strides have been made towards understanding post-injury biological and biomechanical changes in the joint, their interplay, and how they affect healing and PTOA development. However, in order to improve clinical treatments to promote meniscus healing and prevent PTOA development, there is an urgent need to understand the physiologic changes in the joint following injury. In particular, work is needed on the in vivo characterization of the temporal biomechanical and biological changes that occur in patients following meniscus injury and how these changes contribute to PTOA development.

Elevated In Vivo ACL Strain Is Associated With a Straight Knee in Both the Sagittal and the Coronal Planes

BACKGROUND

Noncontact anterior cruciate ligament (ACL) injuries typically occur during deceleration movements such as landing or cutting. However, conflicting data have left the kinematic mechanisms leading to these injuries unclear. Quantifying the influence of sagittal and coronal plane knee kinematics on in vivo ACL strain may help to elucidate noncontact ACL injury mechanisms.

PURPOSE/HYPOTHESIS

The purpose of this study was to measure in vivo sagittal and coronal plane knee kinematics and ACL strain during a single-leg jump. We hypothesized that ACL strain would be modulated primarily by motion in the sagittal plane and that limited coronal plane motion would be measured during this activity.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Seventeen healthy participants (8 male/9 female) underwent magnetic resonance imaging (MRI) followed by high-speed biplanar radiography, obtained as participants performed a single-leg jump. Three-dimensional models of the femur, tibia, and associated ACL attachment site footprints were created from the MRIs and registered to the radiographs to reproduce the position of the knee during the jump. ACL strain, knee flexion/extension angles, and varus/valgus angles were measured throughout the jump. Spearman rank correlations were used to assess relationships between mean ACL strain and kinematic variables.

RESULTS

Mean ACL strain increased with decreasing knee flexion angle (ρ = -0.3; P = .002), and local maxima in ACL strain occurred with the knee in a straight position in both the sagittal and the coronal planes. In addition, limited coronal plane motion (varus/valgus angle) was measured during this activity (mean ± SD, -0.5°± 0.3°). Furthermore, we did not detect a statistically significant relationship between ACL strain and varus/valgus angle (ρ = -0.01; P = .9).

CONCLUSION

ACL strain was maximized when the knee was in a straight position in both the sagittal and coronal planes. Participants remained in <1° of varus/valgus position on average throughout the jump. As a ligament under elevated strain is more vulnerable to injury, landing on a straight knee may be an important risk factor for ACL rupture.

CLINICAL RELEVANCE

These data may improve understanding of risk factors for noncontact ACL injury, which may be useful in designing ACL injury prevention programs.

Transitioning to Outpatient Shoulder Arthroplasty: Safety, Efficiency, and Cost in a Diverse Payer Mix

Outpatient shoulder arthroplasty presents potential clinical benefits but also risk without perioperative optimization. Length of stay depends largely on surgeon preferences, and a large single-surgeon cohort may provide insight into optimal strategies and costs for outpatient shoulder arthroplasty. A single-surgeon cohort of 472 anatomic and reverse shoulder arthroplasties performed between 2017 and 2020 was retrospectively reviewed. Cases were stratified by those who did or did not undergo same-day discharge. The 90-day readmission, discharge to post-acute care, cost, and 45 patient/case factors were examined. Two hundred fifty (53%) underwent same-day discharge, with the proportion of outpatient cases increasing over time to nearly 80%, with no significant difference in 90-day readmissions. Revision cases often underwent same-day discharge, whereas fractures were typically admitted. The cost was significantly higher for inpatients, with implants accounting for 52%. Surgeons may safely transition a substantial proportion of shoulder arthroplasties to same-day discharge with some reassurance regarding cost savings and 90-day readmissions. (Journal of Surgical Orthopaedic Advances 32(4):263-269, 2023).

The Predicted Position of the Knee Near the Time of ACL Rupture Is Similar Between 2 Commonly Observed Patterns of Bone Bruising on MRI

BACKGROUND

Bone bruises observed on magnetic resonance imaging (MRI) can provide insight into the mechanisms of noncontact anterior cruciate ligament (ACL) injury. However, it remains unclear whether the position of the knee near the time of injury differs between patients evaluated with different patterns of bone bruising, particularly with regard to valgus angles.

HYPOTHESIS

The position of the knee near the time of injury is similar between patients evaluated with 2 commonly occurring patterns of bone bruising.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Clinical T2- and T1-weighted MRI scans obtained within 6 weeks of noncontact ACL rupture were reviewed. Patients had either 3 (n = 20) or 4 (n = 30) bone bruises. Patients in the 4-bone bruise group had bruising of the medial and lateral compartments of the femur and tibia, whereas patients in the 3-bone bruise group did not have a bruise on the medial femoral condyle. The outer contours of the bones and associated bruises were segmented from the MRI scans and used to create 3-dimensional surface models. For each patient, the position of the knee near the time of injury was predicted by moving the tibial model relative to the femoral model to maximize the overlap of the tibiofemoral bone bruises. Logistic regressions (adjusted for sex, age, and presence of medial collateral ligament injury) were used to assess relationships between predicted injury position (quantified in terms of knee flexion angle, valgus angle, internal rotation angle, and anterior tibial translation) and bone bruise group.

RESULTS

The predicted injury position for patients in both groups involved a flexion angle <20°, anterior translation >20 mm, valgus angle <10°, and internal rotation angle <10°. The injury position for the 3-bone bruise group involved less flexion (odds ratio [OR], 0.914; 95% CI, 0.846-0.987; P = .02) and internal rotation (OR, 0.832; 95% CI, 0.739-0.937; P = .002) as compared with patients with 4 bone bruises.

CONCLUSION

The predicted position of injury for patients displaying both 3 and 4 bone bruises involved substantial anterior tibial translation (>20 mm), with the knee in a straight position in both the sagittal (<20°) and the coronal (<10°) planes.

CLINICAL RELEVANCE

Landing on a straight knee with subsequent anterior tibial translation is a potential mechanism of noncontact ACL injury.

Isometric Knee Strength is Greater in Individuals Who Score Higher on Psychological Readiness to Return to Sport After Primary Anterior Cruciate Ligament Reconstruction

Background

Anterior cruciate ligament (ACL) injury is extremely common among athletes. Rate of second ACL injury due to surgical graft rupture or contralateral limb ACL injury is approximately 15-32%. Psychological readiness to return to sport (RTS) may be an important predictor of successful RTS outcomes. Psychological readiness can be quantified using the ACL Return to Sport after Injury (ACL-RSI) questionnaire, with higher scores demonstrating greater psychological readiness.

Purpose

The purpose of this study was to investigate differences in functional performance and psychological readiness to return to sport among athletes who have undergone primary ACL reconstruction (ACLR).

Study Design

Descriptive cohort study.

Methods

Eighteen athletes who had undergone primary ACLR were tested at time of RTS clearance. The cohort was divided into two groups, high score (HS) and low score (LS), based on median ACL-RSI score, and performance on static and dynamic postural stability testing, lower extremity isokinetic and isometric strength testing, and single leg hop testing was compared between the groups using an independent samples t-test.

Results

The median ACL-RSI score was 74.17. The average ACL-RSI score was 83.1±6.2 for the HS group and 61.8±8.0 for the LS group. High scorers on the ACL-RSI performed significantly better on isometric knee flexion as measured via handheld dynamometry (22.61% ±6.01 vs. 12.12% ±4.88, p=0.001) than the low score group.

Conclusion

The findings suggest that increased knee flexion strength may be important for psychological readiness to RTS after primary ACLR. Further research is indicated to explore this relationship, however, a continued emphasis on improving hamstring strength may be appropriate during rehabilitation following ACLR to positively impact psychological readiness for RTS.

Level of Evidence

III.

Use of a Novel Multimodal Imaging Technique to Model In Vivo Quadriceps Force and ACL Strain During Dynamic Activity

BACKGROUND

Quadriceps loading of the anterior cruciate ligament (ACL) may play a role in the noncontact mechanism of ACL injury. Musculoskeletal modeling techniques are used to estimate the intrinsic force of the quadriceps acting at the knee joint.

PURPOSE/HYPOTHESIS

The purpose of this paper was to develop a novel musculoskeletal model of in vivo quadriceps force during dynamic activity. We used the model to estimate quadriceps force in relation to ACL strain during a single-leg jump. We hypothesized that quadriceps loading of the ACL would reach a local maximum before initial ground contact with the knee positioned in extension.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Six male participants underwent magnetic resonance imaging in addition to high-speed biplanar radiography during a single-leg jump. Three-dimensional models of the knee joint, including the femur, tibia, patellofemoral cartilage surfaces, and attachment-site footprints of the patellar tendon, quadriceps tendon, and ACL, were created from the magnetic resonance imaging scans. The bone models were registered to the biplanar radiographs, thereby reproducing the positions of the knee joint at the time of radiographic imaging. The magnitude of quadriceps force was determined for each knee position based on a 3-dimensional balance of the forces and moments of the patellar tendon and the patellofemoral cartilage contact acting on the patella. Knee kinematics and ACL strain were determined for each knee position.

RESULTS

A local maximum in average quadriceps force of approximately 6500 N (8.4× body weight) occurred before initial ground contact. ACL strain increased concurrently with quadriceps force when the knee was positioned in extension.

CONCLUSION

This novel participant-specific modeling technique provides estimates of in vivo quadriceps force during physiologic dynamic loading. A local maximum in quadriceps force before initial ground contact may tension the ACL when the knee is positioned in extension.

CLINICAL RELEVANCE

These data contribute to understanding noncontact ACL injury mechanisms and the potential role of quadriceps activation in these injuries.

Females have Lower Knee Strength and Vertical Ground Reaction Forces During Landing than Males Following Anterior Cruciate Ligament Reconstruction at the Time of Return to Sport

Purpose

There is a high rate of second anterior cruciate ligament (ACL) injury (ipsilateral graft or contralateral ACL) upon return-to-sport (RTS) following ACL reconstruction (ACLR). While a significant amount of epidemiological data exists demonstrating sex differences as risk factors for primary ACL injury, less is known about sex differences as potential risk factors for second ACL injury. The purpose of this study is to determine if there are sex-specific differences in potential risk factors for second ACL injury at the time of clearance for RTS.

Methods

Ten male and eight female athletes (age: 20.8 years ±6.3, height: 173.2 cm ±10.1, mass: 76.6 kg ±18.3) participated in the study following ACLR at time of RTS (mean 10.2 months). Performance in lower extremity isokinetic and isometric strength testing, static and dynamic postural stability testing, and a single leg stop-jump task was compared between the sexes.

Results

Normalized for body weight, males had significantly greater isokinetic knee flexion (141±14.1 Nm/kg vs. 78±27.4 Nm/kg, p=0.001) and extension strength (216±45.5 Nm/kg vs. 159±53.9 Nm/kg, p=0.013) as well as isometric flexion (21.1±6.87% body weight vs. 12.5±5.57% body weight, p=0.013) and extension (41.1±7.34% body weight vs. 27.3±11.0% body weight, p=0.016) strength compared to females. In the single-leg stop jump task, males had a greater maximum vertical ground reaction force during landing (332±85.5% vs. 259±27.4% body weight, p=0.027) compared to females.

Conclusions

Based on these results, there are significant differences between sexes following ACLR at the time of RTS. Lower knee flexion and extension strength may be a potential risk factor for second ACL injury among females. Alternatively, the increased maximum vertical force observed in males may be a potential risk factor of second ACL injury in males. Although these results should be interpreted with some caution, they support that rehabilitation programs in the post-ACLR population should be individualized based on the sex of the individual.

Level of Evidence

Level 3.

Venous Thromboembolism Prophylaxis and Hormonal Contraceptive Management Practice Patterns in the Perioperative Period for Anterior Cruciate Ligament Reconstruction

Purpose

To evaluate the venous thromboembolism (VTE) prophylaxis practices of surgeons performing anterior cruciate ligament reconstruction (ACLR) in female patients using hormonal contraceptives.

Methods

Our research team designed an investigational survey using branching logic that was made available to the AANA membership. The survey was designed to identify clinical decision making regarding VTE prophylaxis after ACLR in patients without risk factors for VTE, the counseling of patients about VTE risk associated with hormonal contraceptives, and the use of VTE prophylaxis after ACLR in patients taking hormonal contraceptives.

Results

Ninety-four respondents completed the survey. Eighty-nine respondents identified their gender (63% male and 37% female respondents). Respondents reported performing the following number of ACLRs annually: more than 50 (40%), 30 to 50 (29%), 15 to 30 (29%), and fewer than 15 (2%). Of the respondents, 62 (67%) reported that VTE developed after ACLR in their patients (male patients only, 32%; female patients only, 24%; and both male and female patients, 34%). Sixty-seven percent used chemoprophylaxis after ACLR. Surgeons who asked about hormonal contraceptive use were more likely to be women (P = .01; odds ratio [OR], 4.2). Surgeons who changed their VTE prophylaxis plan as a result of asking about hormonal contraceptive use were more likely to be women (P = .02; OR, 2.8). Surgeons who asked about hormonal contraceptive use were more likely to have female patients with VTE after ACLR (P = .03; OR, 2.9). Surgeons who changed their VTE prophylaxis plan as a result of asking about hormonal contraceptive use were more likely to have female patients with VTE after ACLR (P = .001; OR, 4.6).

Conclusions

There is no standard of care for VTE prophylaxis after ACLR. A surgeon’s own gender and prior clinical experience with VTE after ACLR may influence his or her likelihood to consider a patient’s hormonal contraceptive use regarding VTE risk after ACLR.

Clinical Relevance

The use of hormonal contraception is a risk factor for VTE in female patients undergoing ACLR. It is important to identify current practice patterns and the need for a standard of care.

Overuse Elbow Injuries in Youth Gymnasts

BACKGROUND

Gymnastics is a unique sport that places significant loads across the growing elbow, resulting in unique overuse injuries, some of which are poorly described in the current literature.

PURPOSE

To provide a comprehensive review of the unique overuse elbow injuries seen in youth gymnasts and to provide an up-to-date synthesis of the available literature and clinical expertise guiding treatment decisions in this population.

STUDY DESIGN

Narrative review.

METHODS

A review of the PubMed database was performed to include all studies describing elbow biomechanics during gymnastics, clinical entities of the elbow in gymnasts, and outcomes of operative and/or nonoperative treatment of elbow pathology in gymnasts.

RESULTS

Participation in gymnastics among youth athletes is high, being the sixth most common sport in children. Early specialization is the norm in this sport, and gymnastics also has the highest number of participation hours of all youth sports. As a result, unique overuse elbow injuries are common, primarily on the lateral side of the elbow. Beyond common diagnoses of radiocapitellar plica and osteochondritis dissecans of the capitellum, we describe a pathology unique to gymnasts involving stress fracture of the radial head. Additionally, we synthesized our clinical experience and expertise in gymnastics to provide a sport-specific rehabilitation program that can be used by providers treating surgical and nonsurgical conditions of the elbow and wishing to provide detailed activity instructions to their athletes.

CONCLUSION

Overuse injuries of the elbow are common in gymnastics and include osteochondritis dissecans of the capitellum, radiocapitellar plica syndrome, and newly described radial head stress fractures. A thorough understanding of the psychological, cultural, and biomechanical aspects of gymnastics are necessary to care for these athletes.

Altered lower extremity biomechanics following anterior cruciate ligament reconstruction during single-leg and double-leg stop-jump tasks: A bilateral total support moment analysis

BACKGROUND

Injury to the anterior cruciate ligament (ACL) can lead to long-lasting biomechanical alterations that put individuals at risk of a second ACL injury. Examining the total support moment may reveal between- and within-limb compensatory strategies.

METHODS

Twenty-six participants who were cleared to return to sport following ACL reconstruction were recruited. Each participant completed the single-leg and double-leg stop jump tasks. These tasks were analyzed using force plates and a 3D motion analysis system. The total support moment was calculated by summing the internal moments of the hip, knee and ankle at peak vertical ground reaction force.

FINDINGS

Internal knee extensor moment was lower in the involved limb compared to the uninvolved for both tasks (17.6%, P = 0.022; 18.4%, P = 0.008). No significant between-limb differences were found for the total support moment. The involved limb exhibited an 18.2% decrease in knee joint contribution (P = 0.01) and a 21.6% increase in ankle joint contribution (P = 0.016) to the total support moment compared to the uninvolved limb in the single-leg stop jump task.

INTERPRETATION

Compensation for the involved knee is likely due to altered biomechanics that redistributes load to the uninvolved knee or to adjacent joints of the same limb. A partial shift in joint contribution from the knee to the ankle during the single-leg stop jump task demonstrates a tendency to decrease load to the knee. Further studies are needed to investigate how these adaptations impact the prevalence of subsequent injury and poor joint health.

Immune cell profiles in synovial fluid after anterior cruciate ligament and meniscus injuries

Background

Anterior cruciate ligament (ACL) and meniscus tears are common knee injuries. Despite the high rate of post-traumatic osteoarthritis (PTOA) following these injuries, the contributing factors remain unclear. In this study, we characterized the immune cell profiles of normal and injured joints at the time of ACL and meniscal surgeries.

Methods

Twenty-nine patients (14 meniscus-injured and 15 ACL-injured) undergoing ACL and/or meniscus surgery but with a normal contralateral knee were recruited. During surgery, synovial fluid was aspirated from both normal and injured knees. Synovial fluid cells were pelleted, washed, and stained with an antibody cocktail consisting of fluorescent antibodies for cell surface proteins. Analysis of immune cells in the synovial fluid was performed by polychromatic flow cytometry. A broad spectrum immune cell panel was used in the first 10 subjects. Based on these results, a T cell-specific panel was used in the subsequent 19 subjects.

Results

Using the broad spectrum immune cell panel, we detected significantly more total viable cells and CD3 T cells in the injured compared to the paired normal knees. In addition, there were significantly more injured knees with T cells above a 500-cell threshold. Within the injured knees, CD4 and CD8 T cells were able to be differentiated into subsets. The frequency of total CD4 T cells was significantly different among injury types, but no statistical differences were detected among CD4 and CD8 T cell subsets by injury type.

Conclusions

Our findings provide foundational data showing that ACL and meniscus injuries induce an immune cell-rich microenvironment that consists primarily of T cells with multiple T helper phenotypes. Future studies investigating the relationship between immune cells and joint degeneration may provide an enhanced understanding of the pathophysiology of PTOA following joint injury.

Blood in the joint: effects of hemarthrosis on meniscus health and repair techniques

Injury to the meniscus is common and frequently leads to the development of post-traumatic osteoarthritis (PTOA). Many times meniscus injuries occur coincident with anterior cruciate ligament (ACL) injuries and lead to a bloody joint effusion. Hemarthrosis, or bleeding into the joint, has been implicated in degeneration of joint tissues. The goal of this review paper is to understand the pathophysiology of blood-induced joint damage, the possible effects of blood on meniscus tissue, and the implications for current meniscus repair techniques that involve the introduction of blood-derived products into the joint. In this review, we illustrate the similarities in the pathophysiology of joint damage due to hemophilic arthropathy (HA) and osteoarthritis (OA). Although numerous studies have revealed the harmful effects of blood on cartilage and synovium, there is currently a gap in knowledge regarding the effects of hemarthrosis on meniscus tissue homeostasis, healing, and the development of PTOA following meniscus injury. Given that many meniscus repair techniques utilize blood-derived and marrow-derived products, it is essential to understand the effects of these factors on meniscus tissue and the whole joint organ to develop improved strategies to promote meniscus tissue repair and prevent PTOA development.

Patellar Tendon Orientation and Strain Are Predictors of ACL Strain In Vivo During a Single-Leg Jump

Background:

There is little in vivo data that describe the relationships between patellar tendon orientation, patellar tendon strain, and anterior cruciate ligament (ACL) strain during dynamic activities. Quantifying how the quadriceps load the ACL via the patellar tendon is important for understanding ACL injury mechanisms.

Hypothesis:

We hypothesized that flexion angle, patellar tendon orientation, and patellar tendon strain influence ACL strain during a single-leg jump. Specifically, we hypothesized that patellar tendon and ACL strains would increase concurrently when the knee is positioned near extension during the jump.

Study Design:

Descriptive laboratory study.

Methods:

Models of the femur, tibia, ACL, patellar tendon, and quadriceps tendon attachment sites of 8 male participants were generated from magnetic resonance imaging (MRI). High-speed biplanar radiographs during a single-leg jump were obtained. The bone models were registered to the radiographs, thereby reproducing the in vivo positions of the bones, ligament, and tendon attachment sites. Flexion angle, patellar tendon orientation, patellar tendon strain, and ACL strain were measured from the registered models. ACL and patellar tendon strains were approximated by normalizing their length at each knee position to their length at the time of MRI. Two separate bivariate linear regression models were used to assess relationships between flexion angle and patellar tendon orientation and between ACL strain and patellar tendon strain. A multivariate linear regression model was used to assess whether flexion angle and patellar tendon strain were significant predictors of ACL strain during the inflight and landing portions of the jump.

Results:

Both flexion angle and patellar tendon strain were significant predictors (P < .05) of ACL strain. These results indicate that elevated ACL and patellar tendon strains were observed concurrently when the knee was positioned near extension.

Conclusion:

Concurrent increases in patellar tendon and ACL strains indicate that the quadriceps load the ACL via the patellar tendon when the knee is positioned near extension.

Clinical Relevance:

Increased ACL strain when the knee is positioned near extension before landing may be due to quadriceps contraction. Thus, landing with unanticipated timing on an extended knee may increase vulnerability to ACL injury as a taut ligament is more likely to fail.

How Are Orthopaedic Sports Medicine Physicians Triaging Cases and Using Telehealth in Response to COVID-19? A Survey of AOSSM Membership

BACKGROUND

The COVID-19 pandemic has changed the practice of orthopaedic sports medicine. The threat of COVID-19 persists, and future restrictions to elective procedures are possible. It is important to understand how sports surgeons are prioritizing surgical cases during elective case restrictions and how telehealth is being incorporated into practice.

PURPOSE

To understand how orthopaedic sports surgeons have triaged surgical sports cases and how telehealth is being utilized in response to COVID-19.

STUDY DESIGN

Cross-sectional study.

METHODS

A survey was presented to participants of the American Orthopaedic Society for Sports Medicine (AOSSM) webinar "Handling Sports and COVID-19" and distributed through email to all members of the AOSSM. The survey consisted of 25 questions with 3 sections: demographics, clinical practice, and telehealth. Descriptive statistics were performed.

RESULTS

Overall, 104 respondents participated. Respondents varied with respect to their location, type of clinical practice, and years in practice. The cases with the highest priority during triage included infections, fractures, and traumatic tendon ruptures (eg, quadriceps tendon). Before COVID-19, <14.0% of surgeons used telehealth, and 76.7% had never used telehealth. Now, however, 81.4% of respondents plan to use telehealth at least once a week in their practice. Respondents indicated postoperative visits and return patients as the most appropriate for telehealth. The majority felt that telehealth was not appropriate for new shoulder (65.9%) or knee (55.6%) evaluation. The leading barriers to telehealth use that were identified included, in decreasing order, concerns about clinical appropriateness, accuracy of physical examination, billing/reimbursement, and medicolegal concerns.

CONCLUSION

Telehealth has seen rapid adoption during the COVID-19 pandemic, and the majority of respondents plan to continue using it. It is being used more for established patients rather than new patient visits. For surgical cases, there was a clear triage priority of sports medicine cases, including infections, fractures, and traumatic tendon ruptures. Lower extremity cases had higher priority than upper extremity.

Distribution of Bone Contusion Patterns in Acute Noncontact Anterior Cruciate Ligament-Torn Knees

BACKGROUND

Bone contusions are commonly observed on magnetic resonance imaging (MRI) in individuals who have sustained a noncontact anterior cruciate ligament (ACL) injury. Time from injury to image acquisition affects the ability to visualize these bone contusions, as contusions resolve with time.

PURPOSE

To quantify the number of bone contusions and their locations (lateral tibial plateau [LTP], lateral femoral condyle [LFC], medial tibial plateau [MTP], and medial femoral condyle [MFC]) observed on MRI scans of noncontact ACL-injured knees acquired within 6 weeks of injury.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

We retrospectively reviewed clinic notes, operative notes, and imaging of 136 patients undergoing ACL reconstruction. The following exclusion criteria were applied: MRI scans acquired beyond 6 weeks after injury, contact ACL injury, and previous knee trauma. Fat-suppressed fast spin-echo T2-weighted MRI scans were reviewed by a blinded musculoskeletal radiologist. The number of contusions and their locations (LTP, LFC, MTP, and MFC) were recorded.

RESULTS

Contusions were observed in 135 of 136 patients. Eight patients (6%) had 1 contusion, 39 (29%) had 2, 41 (30%) had 3, and 47 (35%) had 4. The most common contusion patterns within each of these groups were 6 (75%) with LTP for 1 contusion, 29 (74%) with LTP/LFC for 2 contusions, 33 (80%) with LTP/LFC/MTP for 3 contusions, and 47 (100%) with LTP/LFC/MTP/MFC for 4 contusions. No sex differences were detected in contusion frequency in the 4 locations (P > .05). Among the participants, 50 (37%) had medial meniscal tears and 52 (38%) had lateral meniscal tears.

CONCLUSION

The most common contusion patterns observed were 4 locations (LTP/LFC/MTP/MFC) and 3 locations (LTP/LFC/MTP).

Effect of walking on in vivo tibiofemoral cartilage strain in ACL-deficient versus intact knees

Anterior cruciate ligament (ACL) rupture alters knee kinematics and contributes to premature development of osteoarthritis. However, there is limited data regarding the in vivo biomechanical response of tibiofemoral cartilage to activities of daily living (ADLs) in ACL-deficient knees. In this study, eight otherwise healthy participants with chronic unilateral ACL deficiency completed a stress test to assess the effect of 20 min of level treadmill walking at a speed of 2.5 mph on tibiofemoral cartilage in their ACL-deficient and contralateral ACL-intact knees. Three-dimensional surface models developed from pre- and post-activity magnetic resonance (MR) images of the injured and uninjured knees were used to determine compressive strain across multiple regions of tibiofemoral cartilage (medial and lateral tibial plateaus, medial and lateral femoral condyles, medial aspect of femoral condyle adjacent to intercondylar notch of the femur). In the ACL-deficient knees, we observed significantly increased cartilage strain in the region of the medial femoral condyle adjacent to the intercondylar notch (6% in deficient vs. 2% in contralateral, p = 0.01) as well as across the medial and lateral tibial plateaus (4% vs. 3%, p = 0.01) relative to the contralateral ACL-intact knees. Increased compressive strain at the medial intercondylar notch and tibial plateau suggests alterations in mechanical loading or the response to load in these regions, presumably related to altered knee kinematics. These changes may disrupt cartilage homeostasis and contribute to subsequent development of osteoarthritis.

Comparison of the accuracy of telehealth examination versus clinical examination in the detection of shoulder pathology

HYPOTHESIS/BACKGROUND

In 2017, the American Orthopaedic Association advocated for the increased use of telehealth as an assessment and treatment platform, and demand has significantly increased during the coronavirus disease 2019 pandemic. Diagnostic effectiveness (also called overall diagnostic accuracy) and reliability of a telehealth clinical examination vs. a traditional shoulder clinical examination (SCE) has not been established. Our objective is to compare the diagnostic effectiveness of a telehealth shoulder examination against an SCE for rotator cuff tear (RCT), using magnetic resonance imaging (MRI) as a reference standard; secondary objectives included assessing agreement between test platforms and validity of individualized tests. We hypothesize that tests provided in a telehealth platform would not have inferior diagnostic effectiveness to an SCE.

METHODS

The study is a case-based, case-control design. Two clinicians selected movement, strength, and special tests for the SCE that are associated with the diagnosis of RCT and identified similar tests to replicate for a simulated telehealth-based examination (STE). Consecutive patients with no prior shoulder surgery or advanced imaging underwent both the SCE and STE in the same visit using 2 separate assessors. We randomized the order of the SCE or STE. A blinded reader assessed an MRI, to be used as a reference standard. We calculated diagnostic effectiveness, which provides values from 0% to 100% as well as agreement statistics (Kappa) between tests by an assessment platform, and sensitivity, specificity, and likelihood ratios for individual tests in both SCE and STE. We compared the diagnostic effectiveness (overall) of the SCE and STE with a Mann-Whitney U test.

RESULTS

We included 62 consecutive patients with shoulder pain, aged 40 or older; 50 (81%) received an MRI as a reference standard. The diagnostic effectiveness of stand-alone tests was poor regardless of the group, with the exception of a few tests with high specificity. None had greater than 70% accuracy. There was no significant difference between the overall diagnostic effectiveness of the STE and SCE (P = .98). Overall agreement between the STE tests and the SCE tests ranged from poor to moderate (Kappa, 0.07-0.87).

CONCLUSION

This study identified initial feasibility and noninferiority of the physician-guided, patient-performed STE when compared with an SCE in the detection of RCTs. Although these results are promising, larger studies are needed for further validation of an STE assessment platform.

Meniscus-Derived Matrix Bioscaffolds: Effects of Concentration and Cross-Linking on Meniscus Cellular Responses and Tissue Repair

Meniscal injuries, particularly in the avascular zone, have a low propensity for healing and are associated with the development of osteoarthritis. Current meniscal repair techniques are limited to specific tear types and have significant risk for failure. In previous work, we demonstrated the ability of meniscus-derived matrix (MDM) scaffolds to augment the integration and repair of an in vitro meniscus defect. The objective of this study was to determine the effects of percent composition and dehydrothermal (DHT) or genipin cross-linking of MDM bioscaffolds on primary meniscus cellular responses and integrative meniscus repair. In all scaffolds, the porous microenvironment allowed for exogenous cell infiltration and proliferation, as well as endogenous meniscus cell migration. The genipin cross-linked scaffolds promoted extracellular matrix (ECM) deposition and/or retention. The shear strength of integrative meniscus repair was improved with increasing percentages of MDM and genipin cross-linking. Overall, the 16% genipin cross-linked scaffolds were most effective at enhancing integrative meniscus repair. The ability of the genipin cross-linked scaffolds to attract endogenous meniscus cells, promote glycosaminoglycan and collagen deposition, and enhance integrative meniscus repair reveals that these MDM scaffolds are promising tools to augment meniscus healing.

Biceps tenotomy has earlier pain relief compared to biceps tenodesis: a randomized prospective study

PURPOSE

 Surgical management for long head of the biceps (LHB) tendinopathy with either biceps tenotomy or tenodesis is a reliable, but debated treatment option. The aim of this prospective, randomized, single-blinded study is to evaluate differences in pain relief and subjective outcomes between biceps tenotomy versus tenodesis for LHB tendinopathy.

METHODS

 Subjects were randomized and blinded to biceps tenotomy versus arthroscopic tenodesis intra-operatively. Outcomes evaluated included subjective patient outcome scores, pain, and cosmetic deformity. Subjective outcomes scores and pain were analyzed using a two-way ANOVA, controlling for concomitant rotator cuff repair. Binary outcomes were compared using Chi-square tests.

RESULTS

 Thirty-four subjects (31 male, 3 female) with a median age of 56 (range 30-77) were enrolled. Twenty subjects were randomized to tenotomy and 14 to tenodesis. Fifty-six percent had concomitant rotator cuff repairs. The mean VAS pain score at 3 months was lower with tenotomy versus tenodesis. 2-year follow-up demonstrated no statistically significant differences for VAS, ASES, or SANE. 15/20 (75%) subjects with biceps tenotomy reported no pain medication use at the 2-week postoperative visit versus 5/14 (33%) for biceps tenodesis. Popeye deformity was found in 5/20 (25%) of tenotomy subjects versus 1/14 (7%) in tenodesis subjects.

CONCLUSION

Outcomes appear similar between biceps tenotomy versus tenodesis; however, the tenotomy group demonstrated greater incidence of cosmetic deformity but an earlier improvement in postoperative pain.

LEVEL OF EVIDENCE

Treatment Studies, Level II.

Magnetic resonance imaging features of osteochondral lesions of the talus

BACKGROUND

Osteochondral lesions of the talus (OLT) traditionally have been thought to occur anterolaterally or posteromedially. Recent studies utilizing magnetic resonance imaging (MRI) have questioned this teaching. The purpose of this study was to use MRI to describe the location, frequency, and morphology of OLT and determine if any correlations exist between lesion location and other data points.

METHODS

The location, frequency, and size of OLT based on a nine-zone grid were recorded on 77 MRI examinations. Lateral ligaments were inspected for evidence of injury. Stability of the lesions was assessed based on four MRI criteria: presence or absence of cartilage defects, edema-like signal abnormality, T2 bright rim, and/or subchondral cysts. Demographic data including patient age, injury mechanism, and chronicity were recorded. An ANOVA model was used to determine if statistical differences existed between lesion size and location. Pearson correlation coefficients were used to examine any association between lesion location and demographic data.

RESULTS

Most of the lesions were located medially and centrally on the talar dome (54.5%), with the second highest frequency found laterally and centrally (31.2%). With the numbers available there was no statistical difference between the size of the lesions based on location. No strong correlations were found between lesion location and demographic data.

CONCLUSION

This study refutes traditional teachings regarding the location of OLT and supports recent studies showing that most lesions are located medially and centrally on the talar dome.

Isokinetic strength, endurance, and subjective outcomes after biceps tenotomy versus tenodesis: a postoperative study

BACKGROUND

Similar subjective outcomes have been reported for tenotomy or tenodesis of the long head of the biceps. Few studies have reported on postoperative strength and endurance.

HYPOTHESIS

Biceps tenodesis results in superior subjective outcomes, strength, and endurance compared with tenotomy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Participants completed isokinetic strength and endurance testing for elbow flexion and supination on the operative and nonoperative sides a minimum of 2 years after biceps tenotomy or tenodesis. Modified American Shoulder and Elbow Surgeons (MASES) and Single Assessment Numeric Evaluation (SANE) scores were obtained. The operative/nonoperative strength and endurance scores were compared for the tenotomy and tenodesis groups, with the nonoperative shoulder serving as the control for each participant's operative shoulder. Change scores for strength and endurance were reported as percentage increase or decrease as compared with the nonoperative side. Change scores and MASES and SANE scores were compared between the 2 groups. The presence of a "popeye" deformity or pain at the tenodesis site was noted.

RESULTS

Thirty-five patients (19 tenotomy, 16 tenodesis) were studied. No significant difference was noted in postoperative MASES and SANE scores. Operative-side peak supination torque was significantly decreased relative to the nonoperative side in the tenotomy group, which had a significantly larger decrease in supination peak torque than did the tenodesis group on comparison of change scores. No significant difference was noted for peak flexion torque or flexion/supination endurance between operative and nonoperative sides in either group or between change scores for peak flexion torque or flexion/supination endurance in the tenotomy and tenodesis groups. Four tenotomy patients had a popeye deformity, 2 of whom reported painful cramping. Two patients had pain at the tenodesis site.

CONCLUSION

Subjective outcomes are similar for patients treated with tenotomy and tenodesis. Tenotomy decreases supination peak torque relative to the nonoperative side and tenodesis.

MRI evaluation of anterior knee pain: predicting response to nonoperative treatment

OBJECTIVE

Tibial tubercle lateral deviation and patellofemoral chondromalacia are associated with anterior knee pain (AKP). We hypothesized that increased tibial tubercle lateral deviation and patellofemoral chondromalacia on magnetic resonance imaging correlates with the presence of AKP and with failure of nonoperative management.

MATERIALS AND METHODS

In this retrospective comparative study, a blinded musculoskeletal radiologist measured tibial tubercle lateral deviation relative to the trochlear groove in 15 controls, 15 physical therapy responders with AKP, and 15 physical therapy nonresponders with AKP. Patellar and trochlear cartilage was assessed for signal abnormality, irregularity, and defects.

RESULTS

The mean tibial tubercle lateral deviation in controls, physical therapy responders, and physical therapy nonresponders were 9.32 +/- 0.68, 13.01 +/- 0.82, and 16.07 +/- 1.16 mm, respectively (data are mean +/- standard deviation). The correlation coefficients for tubercle deviation, chondromalacia patellae, and trochlear chondromalacia were 0.51 (P < 0.01), 0.44 (P < 0.01), and 0.28 (P < 0.05), respectively. On analysis of variance, tubercle deviation and chondromalacia patellae contributed significantly to prediction of AKP and response to physical therapy. The presence of chondromalacia patellae and a tubercle deviation greater than 14.6 mm is 100% specific and 67% sensitive with a positive predictive value of 100% and negative predictive value of 75% for failure of nonoperative management.

CONCLUSION

Subjects with AKP have more laterally positioned tibial tubercles and are more likely to have patellar chondromalacia. Patients with AKP, chondromalacia patellae, and a tubercle deviation greater than 14.6 mm are unlikely to respond to nonoperative treatment. Knowledge of tibial tubercle lateralization and presence of chondromalacia patellae may assist clinicians in determining patient prognosis and selecting treatment options.

Magnetic resonance imaging evaluation of patellofemoral malalignment

PURPOSE

The purpose of this study was to determine the relationship between anterior knee pain secondary to suspected patellofemoral malalignment and tibial tubercle lateralization, patellar tilt, and patellar lateralization on magnetic resonance imaging.

METHODS

We compared the bony relationships of the knee in patients with anterior knee pain and patients with nonspecific internal derangements of the knee. We measured the lateral deviation of the tibial tubercle and the patella from the trochlea, patellar tilt, and patellar and patellar tendon length.

RESULTS

The symptomatic knees of patients with anterior knee pain had significantly (P < or = .01) greater lateralization of the tibial tubercle and lateral patellar tilt than did knees of the control group. Patella alta appears to be more common in subjects with anterior knee pain.

CONCLUSIONS

Magnetic resonance imaging determination of tibial tubercle lateralization and patellar tilt correlates positively with the clinical diagnosis of anterior knee pain, suggesting that patellofemoral pain is caused by subtle malalignment.

LEVEL OF EVIDENCE

Level III, development of diagnostic criteria on basis of nonconsecutive patients.