Outcomes of Primary Anterior Cruciate Ligament (ACL) Repair for Proximal Tears: A Systematic Review and Meta-Analysis.

The purpose of this study is to compare failure rates among different techniques of primary anterior cruciate ligament (ACL) repair for the treatment of proximal ACL ruptures. Meta-analysis and systematic review were completed, and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Studies from Embase, Cochrane, and PubMed published between June 2011 and June 2022 reporting outcomes of primary ACL repair on proximal tears with a minimum two-year follow-up were included. Primary ACL repair was divided into dynamic, static, and non-augmented repair. The primary outcome was failure rates, and the secondary outcomes included patient-reported outcomes (PROs) and anterior tibial stability (ATT). Eighteen studies on primary ACL repair were included, with a total of 614 patients (ages ranging from 6 to 65, 60% male). Only two studies were level 1 randomized controlled clinical trials. The static repair had a failure rate of 33 out of 261 (12.6%), non-augmented was 17 out of 179 (9.4%), and dynamic repair was 31 out of 174 (17.8%); no statistically significant difference was found comparing the failure rates (p = 0.090). PROs using the International Knee Documentation Committee (IKDC) and Lysholm scores had weighted averages of 91.7 (95% confidence interval (CI): 89.6-93.8) and 94.7 (95% CI: 92.7-96.7), respectively. ATT had a weighted average of 1.668 mm (95% CI: 1.002-2.334). The primary findings of this paper include a 12.6% combined failure rate for primary proximal ACL repair with no significant difference in failure rate or PROs when accounting for the methodology of repair at a minimum two-year follow-up. It is important to note the lack of high-quality randomized controlled trials, the heterogeneity of included studies, and the lack of long-term data. Despite these limitations, the findings of the current analysis suggest that primary repair may be a useful treatment option for indicated candidates with proximal ACL ruptures. Further long-term and higher-quality comparative studies on ACL reconstruction are warranted.

Chronic exertional compartment syndrome is frequently diagnosed through static compartment pressure measurements and managed with fasciotomy: A systematic review.

OBJECTIVES: Chronic exertional compartment syndrome (CECS) can be diagnosed either clinically or with intra-compartmental pressure monitor measurements and can be treated surgically or conservatively. METHODS: A systematic review was performed on diagnostic and treatment modalities for CECS. Included studies were those that reported both their specific diagnostic modality and treatment regimens. Both surgical and conservative treatment strategies were considered. Demographic variables, diagnostic modalities, patient satisfaction and return to sport, the number of surgical incisions used for the anterior compartment fasciotomy, and the specific conservative treatment regimens were also recorded. Diagnostic modalities were grouped into one of three groups: 1) static compartment pressure monitor, 2) dynamic pressure monitoring, and 3) strictly clinical diagnosis. RESULTS: The literature search identified 373 studies, of which 29 were included for final analysis. In total, there were 1270 total patients. Twenty-four studies used static compartment pressure monitors, 5 studies used dynamic pressure monitors and 2 studies used a strictly clinical diagnosis. Surgical management with fasciotomy was performed in 25 studies with a total of 1018 patients, while conservative management was used in 252 patients in 9 studies (5 studies included surgical and conservative treatments). Among surgical studies, 15 used a single-incision technique for anterior compartment fasciotomy, while 6 used a 2-incision technique. The reported satisfaction after fasciotomy was 42-94% while the return to sport was 26-100%. The reported return to sport in conservative management studies was 25-35%. CONCLUSION: This systematic review found that the majority of clinical reports utilize static compartment pressure measurements to diagnose CECS, with fewer studies using dynamic intra-compartment pressure monitors. Additionally, surgical fasciotomy using a single-incision technique was the most common treatment strategy for anterior compartment CECC, with some studies reporting success with the two-incision technique. STUDY DESIGN: Systematic review, level 4.

Evidence-based Risk Stratification for Sport Medicine Procedures During the COVID-19 Pandemic.

Orthopaedic practices have been markedly affected by the emergence of the COVID-19 pandemic. Despite the ban on elective procedures, it is impossible to define the medical urgency of a case solely on whether a case is on an elective surgery schedule. Orthopaedic surgical procedures should consider COVID-19-associated risks and an assimilation of all available disease dependent, disease independent, and logistical information that is tailored to each patient, institution, and region. Using an evidence-based risk stratification of clinical urgency, we provide a framework for prioritization of orthopaedic sport medicine procedures that encompasses such factors. This can be used to facilitate the risk-benefit assessment of the timing and setting of a procedure during the COVID-19 pandemic.

Patellofemoral Joint Contact Pressures: Current Concepts and Use in Patellar Instability Studies.

The patellofemoral joint is thought to be a common source for knee pain. Improper alignment and function of the patellofemoral joint can lead to abnormal contact pressures, which may explain patients' symptoms. In this review, the authors examine techniques for measuring patellofemoral joint contact pressures and summarize the relevant patellofemoral joint anatomy and contact pressures in normal knee kinematics. Finally, they discuss the results of studies investigating contact pressure changes in cases of patellar instability. This includes both reconstruction of the medial patellofemoral ligament and tibial tubercle osteotomy. [Orthopedics. 2019; 42(2):e172-e179.].

A Biomechanical and Structural Comparison of Articular Cartilage and Subchondral Bone of the Glenoid and Humeral Head.

BACKGROUND: The underlying cause of glenohumeral arthritis is poorly understood. Glenohumeral arthrosis patterns have been classified and described, and differential contact stresses within the joint have been implicated as a cause of joint degeneration, but the intrinsic cause of degeneration patterns in the glenohumeral joint (GHJ) remains largely unknown. PURPOSE/HYPOTHESIS: The purpose of this study was to assess morphological and mechanical differences in articular cartilage (AC) and subchondral bone (SCB) of the glenoid and humeral head in matched cadaveric specimens. We hypothesized that there would be significant zone-dependent differences between the intrinsic characteristics (AC thickness, SCB thickness, compressive forces) of the glenoid and humeral head. STUDY DESIGN: Descriptive laboratory study. METHODS: Ten human cadaveric GHJs (mean age, 60.2 years) were dissected to expose articular surfaces to facilitate biomechanical testing. A 2-mm and 6-mm osteochondral plug was harvested at 5 zones (central, anterior, posterior, inferior, superior) on the glenoid and humeral head (N = 200 plugs). Each 2-mm core was histologically sectioned and stained with hematoxylin and eosin. AC thickness measurements were taken using light microscopy. The 6-mm plugs were imaged using micro-computed tomography to measure SCB thickness. After imaging, AC specimens were removed from the SCB and tested in confined compression. The compressive aggregate modulus (HA0), compressive stiffening coefficient (ß), and compressive modulus at 16% strain (HA0.16) and at 50% strain (HA0.50) were calculated. RESULTS: The overall AC thickness was significantly greater on the glenoid. The glenoid also had significantly thicker AC at the inferior, posterior, and superior zones as well as significantly higher SCB thickness overall and significantly greater SCB thickness at the anterior and central zones. The glenoid had significantly greater overall HA0.50 and HA0.50 values at the superior zone and had a significantly greater overall compressive stiffening coefficient (ß). CONCLUSION: The glenoid had thicker AC, thicker SCB, and greater compressive stiffness at high strain. CLINICAL RELEVANCE: These intrinsic differences may help better elucidate the cause of differential degeneration patterns between the glenoid and humeral head.

Biomechanical Comparison of Single- Versus Double-Row Capsulolabral Repair for Shoulder Instability: A Review.

BACKGROUND: The glenohumeral joint is the most commonly dislocated joint in the body. Failure rates of capsulolabral repair have been reported to be approximately 8%. Recent focus has been on restoration of the capsulolabral complex by a double-row capsulolabral repair technique in an effort to decrease redislocation rates after arthroscopic capsulolabral repair. PURPOSE: To present a review of the biomechanical literature comparing single- versus double-row capsulolabral repairs and discuss the previous case series of double-row fixation. STUDY DESIGN: Narrative review. METHODS: A simple review of the literature was performed by PubMed search. Only biomechanical studies comparing single- versus double-row capsulolabral repair were included for review. Only those case series and descriptive techniques with clinical results for double-row repair were included in the discussion. RESULTS: Biomechanical comparisons evaluating the native footprint of the labrum demonstrated significantly superior restoration of the footprint through double-row capsulolabral repair compared with single-row repair. Biomechanical comparisons of contact pressure at the repair interface, fracture displacement in bony Bankart lesion, load to failure, and decreased external rotation (suggestive of increased load to failure) were also significantly in favor of double- versus single-row repair. Recent descriptive techniques and case series of double-row fixation have demonstrated good clinical outcomes; however, no comparative clinical studies between single- and double-row repair have assessed functional outcomes. CONCLUSION: The superiority of double-row capsulolabral repair versus single-row repair remains uncertain because comparative studies assessing clinical outcomes have yet to be performed.

Repair of Medial Patellofemoral, Ligament Improves Patellar, Tracking in Total Knee Replacement.

The medial patellofemoral ligament (MPFL) is essential to maintain patella stability; however, its role in total knee replacement (TKR) has not been studied. Forty-six consecutive TKRs in 40 patients were reviewed. Standard closure was performed in 29 TKRs. The MPFL was isolated and anatomically re-approximated in 17 subsequent TKRs. Blinded radiographic evaluation of patellar tilt and subluxation was performed preoperatively and 4 months postoperatively. Despite greater preoperative lateral tilt, the MPFL repair group demonstrated greater correction in patellar tilt compared with the standard closure group (p = 0.02). Patellar tracking also was optimized in the MPFL group, despite equivalent preoperative lateral patellar subluxation in the two groups. Simple repair of the MPFL at arthrotomy closure appears to optimize patellar stability radiographically and may improve long-term results by minimizing patellar complications and wear.

A review of the anterolateral ligament of the knee: current knowledge regarding its incidence, anatomy, biomechanics, and surgical dissection.

PURPOSE: To systematically review current literature on the anterolateral ligament (ALL) of the knee. METHODS: We searched the PubMed/Medline database for publications specifically addressing the ALL. We excluded studies not written in English, studies not using human cadavers or subjects, and studies not specifically addressing the ALL. Data extraction related to the incidence, anatomy, morphometry, biomechanics, and histology of the ALL and its relation to the Segond fracture was performed. RESULTS: The incidence of the ALL ranged from 83% to 100%, and this range occurs because of small discrepancies in the definition of the ALL's bony insertions. The ALL originates anterior and distal to the femoral attachment of the lateral collateral ligament. It spans the joint in an oblique fashion and inserts between the fibular head and Gerdy tubercle on the tibia. Exact anatomic and morphometric descriptions vary in the literature, and there are discrepancies regarding the ALL's attachment to the capsule and lateral meniscus. The ALL is a contributor to tibial internal rotation stability, and histologically, it exhibits parallel, crimped fibers consistent with a ligamentous microstructure. The footprint of the ALL has been shown to be at the exact location of the Segond fracture. CONCLUSIONS: The ALL is a distinct ligamentous structure at the anterolateral aspect of the knee, and it is likely involved in tibial internal rotation stability and the Segond fracture. LEVEL OF EVIDENCE: Level IV, systematic review of anatomic and imaging studies.

Biomechanics and anatomy of the proximal biceps tendon.

With the role of the biceps tendon being the source of considerable controversy, the treatment of its disease has been even more confusing. Our understanding of its role in shoulder pathology has ranged from describing it as a vestigial structure, to a vital structure of shoulder function with distinct disease pathology. This chapter analyzes the anatomic and biomechanical functions of the proximal biceps tendon.

Articular cartilage thickness of the humeral head: an anatomic study.

This study determined the thickness of normal humeral head articular cartilage by anatomic cross section using computer-aided image analysis software. Sixteen adult cadaveric humeral heads were analyzed. Our findings reveal that the thickness of humeral articular cartilage is substantially thinner than articular cartilage found in the knee. The cartilage is thickest in the central portion of the head and becomes progressively thinner towards the periphery. Surgical techniques used to treat pathology in the glenohumeral joint, specifically thermal energy or mechanical debridement, may have deleterious effects on the relatively thin humeral articular cartilage.

The multi-suture technique for rotator cuff repair: a biomechanical evaluation.

Multi-suture fixation of supraspinatus rotator cuff tears provides excellent fixation and biomechanical failure characteristics.

Strain pattern comparison of double- and single-bundle anterior cruciate ligament reconstruction techniques with the native anterior cruciate ligament.

PURPOSE: The purpose of this study was to dynamically assess the native strain patterns of the anteromedial bundle (AMB) and posterolateral bundle (PLB) of the anterior cruciate ligament (ACL) and compare these findings with graft bundle strain patterns after double-bundle (DB) ACL reconstruction with tibial fixation under 40 N of tension at 75 degrees knee flexion (AMB) and under 20 N of tension at 20 degrees knee flexion (PLB) and after single-bundle (SB) reconstruction with tibial fixation under 40 N of tension at 20 degrees knee flexion. METHODS: The mean strain pattern of the AMB and PLB of the native ACL of 4 cadaveric knees was measured via differential variable reluctance transducers and 2-dimensional kinematic analysis during passive manual knee flexion-extension under a constant axial compression load. Measurements were repeated after DB and SB ACL reconstruction. Celeration line assessments with a split-middle technique were performed to quantify percent strain/knee flexion-extension angle change at reciprocating bundle function transition points. RESULTS: The DB ACL reconstruction technique displayed reciprocating AMB and PLB strain patterns that more closely replicated those of the native ACL. The SB ACL reconstruction technique tended to replicate AMB strain patterns, suggesting poor bundle function differentiation. CONCLUSIONS: The DB ACL reconstruction with differential AMB and PLB tensioning more closely replicated native ACL strain patterns than the SB ACL reconstruction. The SB ACL reconstruction that we used closely simulated native ACL AMB strain patterns; however, PLB function was not restored. CLINICAL RELEVANCE: The DB ACL reconstruction more closely replicated the AMB and PLB strain patterns of the native ACL.

Adolescent baseball pitching technique: a detailed three-dimensional biomechanical analysis.

PURPOSE: Document the biomechanics of the pitching motion to help provide insight about the etiology of common injuries seen in adolescent baseball pitchers. METHODS: Kinematic and kinetic data for the upper and lower extremities, thorax, and pelvis were collected from 24 adolescent pitchers, using modern three-dimensional computerized motion-analysis techniques. RESULTS: Original information regarding forearm and wrist motion was reported in this study and were consistent with expected motions for the fastball pitch. Average excursion of motion was: pronation/supination 63 +/- 15 degrees, wrist flexion/extension 44 +/- 14 degrees, and ulnar/radial deviation 12 +/- 4 degrees. Explosive forearm motion occurred between ball release (BR) and maximal glenohumeral internal rotation (GH-MIR) with a peak pronation velocity of 2051 +/- 646 degrees.s(-1). The majority of internal/external and abduction/adduction shoulder motion was attributed to the glenohumeral motion. Internal glenohumeral rotation range of motion was 125 +/- 13 degrees and mean peak internal glenohumeral rotation velocity was 3343 +/- 453 degrees.s(-1). Thorax and pelvic motion peak velocities and accelerations occurred before the peak elbow varus moment, which occurred at 59% of the pitch cycle (PC). The peak shoulder, elbow, and wrist velocities and accelerations occurred after the peak elbow varus moment. The pelvis squared to the plate at 51 +/- 10% PC and the thorax at 59 +/- 7% PC with maximal glenohumeral external rotation (GH-MER) at 65% PC and BR at 78 +/- 3% PC. The data collected in this study were consistent with the literature, with the exception of joint velocities and moments, which were lower than those in one published study. CONCLUSION: We have established the kinematic and kinetic parameters of the adolescent baseball pitch. These measured parameters and the differences between adolescent pitchers and their adult counterparts can be used to examine and help determine the causes of the rapid increase in adolescent pitching injuries.

Current concepts review: the medial patellofemoral ligament.

Awareness of the medial patellofemoral ligament has increased markedly over the past decade. Previously, this structure, which was delineated in anatomical studies, had been little recognized and underestimated with regard to its importance in stabilizing the patella. The goal of this review of the medial patellofemoral ligament is to develop a current understanding of how this ligament functions in patellofemoral stability and to review the current treatment options for medial patellofemoral ligament disruption.

Evaluation and treatment of acromioclavicular joint injuries.

Acromioclavicular joint injuries and, more specifically, separations are commonplace both in general practice and during athletic participation. This article reviews the traditional classification as well as the clinical evaluation of patients with acute and chronic acromioclavicular joint separations. It also highlights many recent advances, principally in the anatomy and biomechanics of the acromioclavicular joint ligamentous complex. The concept of increases in superior translation as well as disturbances in horizontal translation with injuries to this joint and ligaments are discussed. This information, coupled with the unpredictable long-term results with the Weaver-Dunn procedure and its modifications, have prompted many recent biomechanical studies evaluating potential improvements in the surgical management of acute and chronic injuries. The authors present these recent works investigating cyclic loading and ultimate failure of traditional reconstructions, augmentations, use of free graft, and the more recent anatomic reconstruction of the conoid and trapezoid ligaments. The clinical results (largely retrospective), including acromioclavicular joint repair, reconstruction and augmentation with the coracoclavicular ligament, supplemental sutures, and the use of free autogenous grafts, are summarized. Finally, complications and the concept of the failed distal clavicle resection and reconstruction are addressed. The intent is to provide a current, in-depth treatise on all aspects of acromioclavicular joint complex injuries to include anatomy, biomechanics, benchmark studies on instability and reconstruction, clinical and radiographic evaluation, and to present the most recent clinical research on surgical outcomes.

Novel approach for reconstruction of the posterolateral corner using a free tendon graft technique.

Injuries to the lateral collateral ligament (LCL) and posterolateral corner of the knee, particularly when combined with anterior cruciate or posterior cruciate ligament injuries, can result in profound symptomatic knee instability. Although many surgical improvements have been made in the reconstruction of anterior and posterior cruciate ligament injuries, reconstruction of the posterolateral corner has had less predictable results, with residual pathologic laxity especially in the chronic situation. This has stimulated many surgeons to recommend acute repair of posterolateral knee injuries. This article will briefly review the relevant surgical anatomy, present a summary of current reconstructive techniques for the posterolateral corner, and describe our preferred method for anatomic reconstruction of the posterolateral corner for chronic instability of the knee by recreating the LCL and popliteofibular ligament using either autogenous or allograft soft tissue and an interference screw technique. We do not use a transtibial tunnel but re-orientate the transfibular tunnel and utilize 2 femoral tunnels an the attempt to recreate the LCL and popliteus tendon. In a small clinical series, this has proven to restore varus rotation and external rotation patholaxities with a high degree of predictability.

The biomechanical evaluation of four fixation techniques for proximal biceps tenodesis.

PURPOSE: The purpose of this study was to compare the cyclic displacement and ultimate failure strength of 4 proximal biceps tendon tenodesis fixation methods: the open subpectoral bone tunnel (SBT) biceps tenodesis, the arthroscopic suture anchor (SA) tenodesis, the open subpectoral interference screw (SIS) fixation technique, and the arthroscopic interference screw (AIS) technique. TYPE OF STUDY: Biomechanical experimental control. METHODS: Twenty fresh-frozen cadaver shoulders were dissected free of soft tissues, leaving the proximal humerus and the proximal biceps tendon as a free graft. Specimens were randomized to 1 of 4 groups with 5 total specimens in each group. A proximal biceps tenodesis was performed according to the techniques listed above. The specimens were mounted for an axial pull of the biceps tendon on a servohydraulic materials testing system with a 100-N load cycled at 1 Hz for 5,000 cycles, followed by an axial load to failure test. Cyclic displacement, ultimate load to failure, and site of failure were recorded for each specimen. RESULTS: The mean cyclic displacement recorded for each experimental group was as follows: SBT group, 9.39 +/- 2.82 mm; AIS group, 5.26 +/- 2.60 mm; SIS group, 1.53 +/- 0.60 mm; and SA group, 3.87 +/- 2.11 mm. The mean ultimate failure loads after 5,000 cycles were as follows: SBT group, 242.4 +/- 51.33 N; AIS group, 237.6 +/- 27.58 N; SIS group, 252.4 +/- 68.63 N; and SA group, 164.8 +/- 37.47 N. Each specimen failed at the tenodesis site. CONCLUSIONS: The SBT group showed statistically significant greater displacement than the other tenodesis methods. There were no statistically significant differences in ultimate failure strength between any of the biceps tenodesis methods tested. CLINICAL RELEVANCE: The data serve as a guide to the surgeon performing a proximal biceps tenodesis in choosing a fixation method.

The glenoid center line.

This study sought to define a point on the anterior glenoid surface to serve as a marker for glenoid orientation and to present the concept of a glenoacromial version angle. Twenty fresh-frozen cadaver scapulas were examined. A line perpendicular to the glenoid surface exited the anterior scapular cortex in all specimens at an average distance of 29.3 +/- 3.9 mm. The average glenoacromial version angle was 60 degrees +/- 110 degrees. These numbers may allow better intraoperative assessment of glenoid version.

Treatment and results of sternoclavicular joint injuries.

Sternoclavicular joint injuries are uncommon. The anatomy is not familiar to most orthopaedic surgeons, and there is a high risk of both intraoperative catastrophic and postsurgical complications when performing surgery in this region. Anterior SC joint instability should primarily be treated conservatively. The patients should be informed that there is a high risk of persistent instability with nonoperative or operative care, but that the persistent instability will be well tolerated and have little functional impact in the vast majority. Therefore, operative intervention for anterior SC joint instability is mainly cosmetic in nature. Patients with posterior SC joint dislocations require an expeditious diagnosis and treatment, due to the proximity of the displaced medial clavicle to the great vessels. An early closed reduction will usually be stable. Operative stabilization must, however, be considered if the closed reduction is unsuccessful or there is persistent SC instability. SC joint stabilization should be performed with a soft tissue reconstruction, repairing both the costoclavicular ligaments and the SC capsular envelope.