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Background: The treatment of patients who suffer a proximal humeral fracture (PHF) remains controversial. The purpose of this study was to find consensus among experts using a validated iterative process in the treatment of patients after a PHF., Methods: The Neer Circle is an organization of shoulder experts recognized for their service to the American Shoulder and Elbow Surgeons. Consensus among 86 identified experts from this group was sought with a series of surveys using the Delphi process. The first three surveys included vignettes with 2-part, 3-part, and 4-part fractures, under two scenarios, (1) a healthy 55-year-old and (2) and a 75-year-old with significant medical comorbidities. Within each vignette, respondents were asked about their preference on CT utilization, and whether they would select operative or nonoperative treatment. A final survey was administered to elicit respondent preferences on general treatment approaches regardless of specific vignette characteristics., Results: Consensus was reached on the value of CT scans with 3D reconstructions, age as an important factor in determining treatment, functional demand, fracture pattern, bone quality, and the presence of more significant medical comorbidities would strongly impact decision making. Experts agreed that medial calcar involvement would have no impact on their decision, and gender and non-dominant arm involvement would have a low impact. Consensus was reached in the following scenarios for an operative treatment in a young and healthy patient: 2-part shaft fracture (V3, 98%); 3-part varus fracture (V5, 98%); 3-part valgus fracture (V7, 98%); 4-part fracture (V9, 100%); 4-part dislocation fracture (V11, 98%) and 4-part valgus impacted fractures (V13, 95%). For older unhealthy patients in 4- part dislocation fractures (V12, 100%). In the remainder of scenarios, there was no consensus reached for preferred treatment, either operative or nonoperative. Finally, there was no consensus on preferred rehab protocols, whether for nonoperative management or postoperative care., Conclusion: In conclusion, this study demonstrates that consensus when managing proximal humerus fractures is limited to specific scenarios, while lack of consensus still exists in others. The presented study advocates non-operative treatment of proximal humerus fractures in the sicker patient and surgical treatment methods for 3-part and 4-part fractures in the young, healthy patient., (Copyright © 2025. Published by Elsevier Inc.)

Background: Thoracic outlet syndrome (TOS) remains a rare diagnosis but is being recognized as a cause of upper extremity dysfunction in professional baseball players., Purpose/hypothesis: The purpose was to determine performance and return-to-play (RTP) outcomes in professional baseball players after surgical treatment of TOS. The hypothesis was that there would be a high RTP rate in professional baseball players after TOS surgery with no statistical differences in performance between pitchers who had TOS surgery and matched controls., Study Design: Cohort study; Level of evidence, 3., Methods: All professional baseball players who underwent surgical treatment of TOS between 2010 and 2017 were identified using the Major League Baseball Health and Injury Tracking System database. Demographic and performance data (before and after surgery) for each player were recorded. Performance variables were then compared between players who underwent TOS surgery and matched controls. The matching criteria were no history of previous surgeries on affected arm, age at time of surgery, throwing side, level of play (Major or Minor League Baseball), and years of experience playing professional baseball., Results: Overall, 52 players underwent surgery for TOS, of whom 46 (88%) were pitchers. The type of TOS was neurogenic in 69% and venous in 29%. One player had arterial TOS. After TOS surgery, 79% of players returned to play at the same or higher level (RTSP) by 9.5 months and played ≥3 years after surgery. No differences were found in RTSP rate based on the type of TOS. No statistical difference was found in RTP rates between major and minor league players. Pitchers had a 76% RTSP, which was similar to the natural attrition for control pitchers ( P = .874). After TOS surgery, pitchers saw a decline in several performance metrics, but these declines were not different from those of control pitchers, indicating that the decline in performance after TOS surgery was no faster than is seen in healthy professional pitchers as they age., Conclusion: The rate of RTSP after surgery for TOS in professional baseball players was 79%. There was no difference in RTP based on the type of TOS. Pitchers who underwent surgery for TOS had no significant differences in pitching performance metrics after surgery compared with matched controls., Competing Interests: Presented as a poster at the annual meeting of the AOSSM, Colorado Springs, Colorado, July 2022.One or more of the authors has declared the following potential conflict of interest or source of funding: A.C. has received support for education from Medwest Associates, Smith & Nephew, Axogen, and SportsTek Medical; speaking fees from Covidien; a grant from DJO; and hospitality payments from Encore Medical and TriMed. P.N.C. has received IP royalties from Responsive Arthroscopy and DePuy; consulting fees from DePuy, DJ Orthopedics, Medical Device Business Services, and Encore Medical; hospitality payments from Smith & Nephew; support for education from Active Medical; and compensation for services other than consulting from Arthrex. B.J.E. has received consulting fees from Arthrex and DePuy; research support from Arthrex, DePuy, Linvatec, Smith & Nephew, and Stryker; and support for education from Pinnacle and Gotham Surgical. A.A.R. has received royalties and consulting fees from Arthrex and research support from Arthrex and Paragen Technologies; he holds stock or stock options in Paragen Technologies. H.R.H. has received consulting fees from Smith & Nephew, Stryker, and Wright Medical Technology; royalties from Stryker and Wright Medical Technology; and hospitality payments from Integra LifeSciences Corporation. K.M. and Z.T. are employees of Major League Baseball. J.F. has received support for education from ImpactOrtho and hospitality payments from Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Background: Large osteochondral lesions of the humeral head can result from locked posterior dislocations, avascular necrosis, and osteochondritis dissecans. Fresh osteochondral allograft (OCA) transplantation is a treatment option for young patients with focal osteochondral defects of the humeral head. The purpose of this case series was to assess graft survivorship, subjective patient-reported outcomes, and satisfaction among 7 patients who underwent OCA transplantation of the humeral head., Methods: We identified 7 patients who underwent humeral head OCA transplantation between 2008 and 2017. A custom questionnaire including the American Shoulder and Elbow Surgeons score, Quick Disabilities of the Arm, Shoulder, and Hand score (QuickDash), Likert satisfaction, and reoperations was mailed to each patient. Clinical failure was defined as further surgery that involved removal of the allograft., Results: Median follow-up duration was 10 years (range, 4.6 to 13.5 years) with a median age of 21.6 years (range, 18.5 to 43.5 years). Most patients (86%) reported improved function and reduced pain. At the final follow-up, 71% of patients reported ongoing problems with their shoulder including pain, stiffness, clicking/grinding, limited range of motion, and instability. Return to recreational activities was high at 86% but 43% expressed limitations with activity due to their shoulder. Overall satisfaction was high at 71% with mean American Shoulder and Elbow Surgeons and QuickDASH scores at 62.4 and 29.2, respectively. Reoperation after OCA occurred in 1 patient (14%)., Conclusion: Among this case series of 7 patients who underwent OCA transplantation of the humeral head, patient satisfaction was high at 10-year follow-up and most returned to recreational activity although most also had persistent shoulder symptoms., (© 2024 The Authors.)

Background: This article examines the wide range of surgical reconstruction options available for acromioclavicular (AC) joint injuries. However, the lack of consensus regarding the most suitable surgical techniques is attributed to the high and variable failure rates observed with current approaches., Methods: This article presents a comprehensive overview of the current surgical principles and techniques used by renowned experts in the field of AC shoulder injury management., Results: It emphasizes the significance of addressing horizontal and rotational instability in AC injuries and highlights the impact of impaired scapular biomechanics., Conclusion: By exploring these emerging concepts and strategies, the article aims to lay the foundation for future studies aimed at improving treatment outcomes and patient management., (© 2023 The Author(s).)

Background: Recent studies evaluating nonoperative treatment of elbow ulnar collateral ligament (UCL) injuries augmented with platelet-rich plasma (PRP) have shown promising results. To date, no comparative studies have been performed on professional baseball players who have undergone nonoperative treatment with or without PRP injections for UCL injuries., Hypothesis: Players who received PRP injections would have better outcomes than those who did not receive PRP., Study Design: Cohort study; Level of evidence, 3., Methods: The Major League Baseball (MLB) Health and Injury Tracking System identified 544 professional baseball players who were treated nonoperatively for elbow UCL injuries between 2011 and 2015. Of these, 133 received PRP injections (PRP group) before starting their nonoperative treatment program, and 411 did not (no-PRP group). Player outcomes and a Kaplan-Meier survival analysis were compared between groups. In addition, to reduce selection bias, a 1:1 matched comparison of the PRP group versus the no-PRP group was performed. Players were matched by age, position, throwing side, and league status: major (MLB) and minor (Minor League Baseball [MiLB]). A single radiologist with extensive experience in magnetic resonance imaging (MRI) interpretation of elbow injuries in elite athletes analyzed 243 MRI scans for which images were accessible for tear location and grade interpretation., Results: Nonoperative treatment of UCL injuries resulted in an overall 54% rate of return to play (RTP). Players who received PRP had a significantly longer delay in return to throwing ( P < .001) and RTP ( P = .012). The matched cohort analysis showed that MLB and MiLB pitchers in the no-PRP group had a significantly faster return to throwing ( P < .05) and the MiLB pitchers in the no-PRP group had a significantly faster RTP ( P = .045). The survival analysis did not reveal significant differences between groups over time. The use of PRP, MRI grade, and tear location were not statistically significant predictors for RTP or progression to surgery., Conclusion: In this retrospective matched comparison of MLB and MiLB pitchers and position players treated nonoperatively for a UCL tear, PRP did not improve RTP outcomes or ligament survivorship, although there was variability with respect to PRP preparations, injection protocols, time from injury to injection, and rehabilitation programs. MRI grade and tear location also did not significantly affect RTP outcomes or progression to surgery.

Objective: Mesenchymal stem cells (MSCs) are a promising cell-based therapy treatment option for several orthopedic indications. Because culture expansion of MSC is time and cost intensive, a bedside concentration of bone marrow (BM) aspirate is used as an alternative. Many commercial systems are available but the available literature and knowledge regarding these systems is limited. We compared different point-of-care devices that concentrate BM (BMC) by focusing on technical features and quality parameters to help surgeons make informed decisions while selecting the appropriate device., Methods: We compared published data on the BMC devices of Arteriocyte, Arthrex, Celling Biosciences, EmCyte, Exactech, ISTO Tech, Harvest Tech/Terumo BCT, and Zimmer/BIOMET regarding technical features (centrifugation speed/time, input/output volume, kit components, type of aspiration syringes, filter usage) and quality parameters of their final BMC product (hematocrit, concentration of platelets and total nucleated cells, concentration of MSC and connective tissue progenitor cells)., Results: The systems differ significantly in their technical features and centrifugation parameters. Only the fully automated systems use universal kits, which allow processing different volumes of BM. Only the Arthrex system allows selection of final hematocrit. There was no standardized reporting method to describe biologic potency., Conclusions: Based on the data obtained in this review, recommending a single device is not possible because the reported data could not be compared between devices. A standardized reporting method is needed for valid comparisons. Furthermore, clinical outcomes are required to establish the true efficacy of these systems. We are conducting additional studies for more careful comparison among the devices.

Hypothesis: Musculoskeletal computer models provide valuable insights into shoulder biomechanics. The shoulder is a complex joint composed of glenohumeral, scapulothoracic, acromioclavicular, and sternoclavicular articulations, whose function is largely dependent on the many muscles spanning these joints. However, the range of patient-to-patient variability in shoulder function is largely unknown. We therefore assessed the sensitivity of glenohumeral forces to population-based model input parameters that were likely to influence shoulder function., Methods: We constructed musculoskeletal models of the shoulder in the AnyBody Modeling System (AnyBody Technology, Aalborg, Denmark). We used inverse dynamics and static optimization to solve for glenohumeral joint forces during a simulated shoulder elevation. We generated 1000 AnyBody models by uniformly distributing the following input parameters: subject height, scapulohumeral rhythm, humeral head radius, and acromiohumeral interval., Results: Increasing body height increased glenohumeral joint forces. Increasing the ratio of scapulothoracic to glenohumeral elevation also increased forces. Increasing humeral head radius and acromiohumeral interval decreased forces. The relative sensitivity of glenohumeral joint forces to input parameters was dependent on the angle of shoulder elevation. We developed an efficient method of generating and simulating musculoskeletal models representing a large population of shoulder arthroplasty patients. We found that scapulohumeral rhythm had a significant influence on glenohumeral joint force., Conclusions: This finding underscores the importance of more accurately measuring and simulating scapulothoracic motion rather than using fixed ratios or average scapulothoracic motion. This modeling approach can be used to generate virtual populations for conducting efficient simulations and generating statistical conclusions.

Hypothesis: Glenoid retroversion can be corrected with standard glenoid implants after anterior-side asymmetric reaming or by using posterior augmented glenoid implants with built-in corrections. The purpose of this study was to compare 2 augmented glenoid designs with a standard glenoid design, measure the amount of bone removed, and compute the stresses generated in the cement and bone., Methods: Finite element models of 3 arthritic scapulae with varying severities of posterior glenoid wear were each implanted with 4 different implant configurations: standard glenoid implant in neutral alignment with asymmetric reaming, standard glenoid implant in retroversion, glenoid implant augmented with a posterior wedge in neutral alignment, and glenoid implant augmented with a posterior step in neutral alignment. The volume of cortical and cancellous bone removed and the percentage of implant back surface supported by cortical bone were measured. Stresses and strains in the implant, cement, and glenoid bone were computed., Results: Asymmetric reaming for the standard implant in neutral version required the most bone removal, resulted in the lowest percentage of back surface supported by cortical bone, and generated strain levels that risked damage to the most bone volume. The wedged implant removed less bone, had a significantly greater percentage of the back surface supported by cortical bone, and generated strain levels that risked damage to significantly less bone volume., Conclusions: The wedged glenoid implants appear to have various advantages over the standard implant for the correction of retroversion., Level of Evidence: Basic Science Study; Computer Modeling., (Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Primary glenohumeral osteoarthritis with posterior wear of the glenoid and posterior subluxation of the humerus (Walch type B) presents a challenge to the treating surgeon. Our hypothesis was that glenoids with biconcavity (B2) would be associated with worse outcomes (functional scores and complications) than B1 glenoids., Materials and Methods: We retrospectively analyzed prospectively collected data on 112 anatomic total shoulder arthroplasties (104 patients) with B glenoids. Preoperative computed tomography identified 64 B1 glenoids and 48 B2 glenoids (50 and 37 available for follow-up)., Results: A significant difference between B1 and B2 glenoids was noted in average retroversion (11° vs. 16°; P < .001) and average posterior humeral subluxation (65% vs. 75%; P < .001). No significant difference was seen in mean age (69.5 vs. 69.2 years) or body mass index (28.5 vs. 27.4) at time of surgery. At average follow-up of 60 months (range, 23-120 months), glenoid component radiolucencies (51.6%, B1; 47.9%, B2), range of motion, preoperative and postoperative scores of the shortened Disabilities of the Arm, Shoulder, and Hand questionnaire, and patient satisfaction were not significantly different between the 2 groups. Four revisions (4.6%) were documented for acute postoperative infection (2.3%), subscapularis failure (1.1%), and glenoid loosening (1.1%)., Conclusions: Although biconcave glenoids commonly have more severe retroversion and posterior subluxation of the humerus, we were unable to find a clinical or radiographic difference in outcome of patients with B1 or B2 glenoids treated with anatomic total shoulder arthroplasty at intermediate-term follow-up. Continued clinical and radiographic follow-up of these cohorts will be necessary to assess any future divergence in outcome., (Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background and Hypothesis: Total shoulder arthroplasty is recommended treatment for severe osteoarthritis of the glenohumeral joint, which often results in excessive posterior wear. Two recent glenoid components with posterior augments have been designed to correct excessive posterior wear and retroversion. Our primary hypothesis was that posterior augmented glenoid designs require less bone removal than a standard glenoid design., Methods: Ten arthritic scapulae classified as Walch B2 glenoids were virtually implanted with standard, stepped, and wedged components. The volume of surgical bone removal, the maximum reaming depth, and the portion of the implant surface in contact with cancellous vs. cortical bone were calculated for each implant., Results: The neoglenoid made up an average of 65% ± 12% of the glenoid width. Mean surgical bone volume removed was least for the wedged (2857 ± 1618 mm(3)) compared with the stepped (4307 ± 1485 mm(3); P < .001) and standard (5385 ± 2348 mm(3); P < .001) designs. Maximum bone depth removed for the wedged (4.2 ± 2.0 mm) was less than for the stepped (7.6 ± 1.2 mm; P < .001) and standard (9.9 ± 3.2 mm; P < .001). The mean percentage of the implant's back surface supported by cancellous bone was 18.2% for the standard, 8.8% for the stepped (P = .02), and 4.3% for the wedged (P = .01)., Discussion: Both augmented components corrected glenoid version to neutral and required less bone removal, required less reaming depth, and were supported by more cortical bone than in the standard implant. The least amount of bone removed was with the wedged design., (Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Injuries to the glenoid labrum frequently require repair with anchors. Placing anchor devices arthroscopically can be challenging, and anchor malpositioning can complicate surgical outcomes., Purpose: To determine the safe insertion range and optimal insertion angle of glenoid labral anchors at various positions on the glenoid rim and to establish surgical guidelines that minimize risk of anchor perforation., Study Design: Descriptive laboratory study., Methods: Three-dimensional computed tomography scans of 30 normal cadaveric specimens were obtained. A virtual model of a generic labral anchor was inserted into the rim of the glenoid at the clockface positions represented by 12:00, 1:30, 3:00, 4:30, 6:00, 7:30, 9:00, and 10:30. At each position, the safe insertion range was the maximal range measured, and the optimal insertion angle was identified as the angle between the bisector of the safe insertion range and the glenoid face., Results: Progressing in the clockwise direction, beginning at the 12:00 position, the safe insertion ranges (mean ± SD ) were 55.9° ± 10.6°, 63.6° ± 17.6°, 47.7° ± 9.1°, 46.1° ± 8°, 73.9° ± 9.7°, 40.9° ± 6.5°, 40.4° ± 7.4°, and 39.9° ± 7.1°, respectively. The optimal insertion angles were 47.9° ± 7.6°, 53.1° ± 10.9°, 35.0° ± 4.4°, 42.4° ± 4.9°, 60.9° ± 8.4°, 36.6° ± 5.9°, 31.2° ± 4.9°, 34.8° ± 4.6°, respectively., Conclusion: Optimal insertion angles and safe insertion ranges varied significantly with respect to the position on the glenoid face. The safe insertion range and optimal insertion angle were found to be wider at the anterior glenoid as compared with the posterior glenoid. A posterolateral insertion angle was safer than an anterior insertion angle at the 10:30 position., Clinical Relevance: Proper arthroscopic technique resulting in anchor insertion at the correct angle, depth, and location will prevent anchor-related glenohumeral complications such as glenoid perforation, cartilage damage, persistent pain, decreased range of motion, and failure of the reconstruction.

Background: Although the majority of Major League Baseball teams use an orthopaedic rating system to evaluate draft picks, little has been published on the topic., Hypothesis: Our goal was to assess the attitudes among Major League Baseball physicians regarding 3 common diagnoses in pitching prospects, through the use of an orthopaedic rating system. Our hypothesis was that the assigned orthopaedic grades would vary among physicians, diagnoses, and operative-versus-nonoperative and recent-versus-past treatment., Study Design: Survey., Level of Evidence: Level 4., Methods: A survey in the form of 12 clinical vignettes was used to query Major League Baseball physicians regarding ulnar collateral ligament (UCL) injuries, type II superior labrum anterior posterior (SLAP) tears, and internal impingement. Respondents graded draft picks using an orthopaedic rating system. The vignettes covered both operative and nonoperative and recent and past treatment (successful return to pitching for 1 year)., Results: THE ORTHOPAEDIC GRADES ASSIGNED BY RESPONDENTS WERE AS FOLLOWS (MINIMAL, MODERATE, SEVERE RISK): past UCL reconstruction (73%, 27%, 0%), recent UCL reconstruction (19%, 77%, 4%), past UCL strain (28%, 60%, 12%), recent UCL strain (0%, 48%, 52%), past SLAP repair (52%, 48%, 0%), recent SLAP repair (4%, 64%, 32%), past SLAP nonoperative (28%, 60%, 12%), recent SLAP nonoperative (0%, 36%, 64%), past internal impingement operative (24%, 68%, 8%), recent internal impingement operative (8%, 32%, 60%), past internal impingement nonoperative (24%, 68%, 8%), and recent internal impingement nonoperative (4%, 48%, 44%)., Conclusion: Team physicians are optimistic regarding the outcome of UCL reconstruction. In contrast, UCL strains, type II SLAP lesions, and internal impingement carry a guarded prognosis. For all diagnoses, regardless of treatment, the prognosis improved if a player returned to pitching for 1 full season., Clinical Relevance: This study represents a first step toward developing a standardized orthopaedic rating system that will facilitate more accurate player assessment and clearer communication among physicians.

Background: Medialization of the glenohumeral center of rotation alters the moment arm of the deltoid, can affect muscle function, and increases the risk for scapular notching due to impingement. The objective of this study was to determine the effect of position of the glenosphere on deltoid efficiency and the range of glenohumeral adduction., Methods: Scapulohumeral bone models were reconstructed from computed tomography scans and virtually implanted with primary or reverse total shoulder arthroplasty implants. The placement of the glenosphere was varied to simulate differing degrees of "medialization" and inferior placement relative to the glenoid. Muscle and joint forces were computed during shoulder abduction in OpenSim musculoskeletal modeling software., Results: The average glenohumeral joint reaction forces for the primary total shoulder arthroplasty were within 5% of those previously reported in vivo. Superior placement or full lateralization of the glenosphere increased glenohumeral joint reaction forces by 10% and 18%, respectively, relative to the recommended reverse total shoulder arthroplasty position. The moment arm of the deltoid muscle was the highest at the recommended baseline surgical position. The baseline glenosphere position resulted in a glenohumeral adduction deficit averaging more than 10° that increased to more than 25° when the glenosphere was placed superiorly. Only with full lateralization was glenohumeral adduction unaffected by superoinferior placement., Discussion/conclusion: Selecting optimum placement of the glenosphere involves tradeoffs in bending moment at the implant-bone interface, risk for impingement, and deltoid efficiency. A viable option is partially medializing the glenosphere, which retains most of the benefits of deltoid efficiency and reduces the risk for scapular notching., (Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: This study undertook a computational analysis of a wedged glenoid component for correction of retroverted glenoid arthritic deformity to determine whether a wedge-shaped glenoid component design with a built-in correction for version reduces excessive stresses in the implant, cement, and glenoid bone. Recommendations for correcting retroversion deformity are asymmetric reaming of the anterior glenoid, bone grafting of the posterior glenoid, or a glenoid component with posterior augmentation. Eccentric reaming has the disadvantages of removing normal bone, reducing structural support for the glenoid component, and increasing the risk of bone perforation by the fixation pegs. Bone grafting to correct retroverted deformity does not consistently generate successful results., Methods: Finite element models of 2 scapulae models representing a normal and an arthritic retroverted glenoid were implanted with a standard glenoid component (in retroversion or neutral alignment) or a wedged component. Glenohumeral forces representing in vivo loading were applied and stresses and strains computed in the bone, cement, and glenoid component., Results: The retroverted glenoid components generated the highest compressive stresses and decreased cyclic fatigue life predictions for trabecular bone. Correction of retroversion by the wedged glenoid component significantly decreased stresses and predicted greater bone fatigue life. The cement volume estimated to survive 10 million cycles was the lowest for the retroverted components and the highest for neutrally implanted glenoid components and for wedged components., Conclusion: A wedged glenoid implant is a viable option to correct severe arthritic retroversion, reducing the need for eccentric reaming and the risk for implant failure., (Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Introduction: Humeral avulsion of the inferior glenohumeral ligament is a rare injury in athletes and can involve different parts of the complex. Axillary pouch avulsion, in particular, has only recently been recognized in the literature, but has never been described in professional baseball pitchers., Materials and Methods: A retrospective review of professional baseball players presenting to our institution over 5 years was performed. Patients with Bankart lesions or fractures were excluded. Preoperative MRI was retrospectively correlated with the clinical and arthroscopic findings, as available., Results: Four professional baseball pitchers were identified, all who had axillary pouch humeral avulsions of the inferior glenohumeral ligament. There was a concomitant avulsion of the anterior band in one patient. Associated findings included labral tears (n = 2) and partial thickness tear of the rotator cuff (n = 2). Three patients ultimately had their axillary pouch avulsions repaired at most recent follow-up., Conclusions: APHAGL lesions can be seen in overhead athletes such as baseball pitchers and should be carefully considered as a potential cause of disability. Appropriate diagnosis is important to ultimately elucidate the optimal management of these lesions.

Background: Press-fit humeral components for total shoulder arthroplasty have notable potential complications that may be minimized by preoperative templating and improvements in stem design. The purpose of this study was to develop a 3-dimensional templating technique for the humeral stem and to validate this templating in cadaveric specimens., Materials and Methods: A cylindrical stem and a stem with a rectangular cross-section were selected for templating and force measurements. Templating was carried out for 15 clinical patients and 16 cadaveric shoulders, including calculation of the cortical-implant volume ratio (CIVR). Insertion forces for stem broaching and impaction were measured for 15 patients and 8 paired cadaveric shoulders. Hoop strain and periprosthetic fractures were monitored in cadaveric shoulders with strain gauges., Results: A significant difference in the CIVR was noted between rectangular and cylindrical stems. No difference was observed in impact forces for ideally sized rectangular or cylindrical stems. A difference in insertion forces was found between oversized cylindrical and oversized rectangular implant stems and also between ideal and oversized cylindrical implant stems. The difference in maximal hoop strain between ideally sized rectangular and cylindrical stems was also statistically significant., Conclusions: CIVR is useful to predict an ideal humeral stem size. Cylindrical stems have a different design rationale for fixation than rectangular stems. Surgeon awareness of the fixation rationale for a particular stem design is important because different stem types have different effects on the insertion force. More anatomic humeral stem designs may help to minimize the risk of complications and optimize stem fixation., (Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Background: Glenoid retroversion is thought be important in shoulder stability before and after shoulder arthroplasty; thus, many authors recommend glenoid reaming to correct retroversion and improve stability. Genetic analysis has revealed that glenoid vault and scapular development are controlled by different genes and environmental factors, resulting in diverse glenoid morphologies. We therefore analyzed the relative contribution of glenoid morphology and version to humeral head position., Materials and Methods: We obtained 121 shoulder computed tomography scans preoperatively for shoulder arthroplasty. Humeral subluxation and glenoid version were measured on the axial image at the middle of each glenoid. Glenoid morphology was characterized as biconcave, worn, displaced, dysplastic, angled, or neutral. The strength of the correlation between humeral subluxation, glenoid version, and glenoid morphology was analyzed., Results: Glenoid version did not correlate with humeral subluxation. The highest frequency of posterior subluxation was noted in biconcave glenoids. Shoulders with other glenoid morphologies were more likely to have anterior or central positioning of the humerus. The mean subluxation ratio for biconcave glenoids was 0.56 and was significantly different from all other morphologies (P < .02)., Discussion/conclusion: Even in the arthritic shoulder, glenoid orientation does not appear to explain the complex biomechanics of shoulder stability. The causes of humeral head subluxation before and after total shoulder arthroplasty are likely multifactorial and may include static and dynamic soft-tissue forces. The biconcave glenoid deserves more attention at surgery because of the high association with posterior subluxation., (Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Force production in skeletal muscle is proportional to the amount of overlap between the thin and thick filaments, which, in turn, depends on their lengths. Both thin- and thick-filament lengths are precisely regulated and uniform within a myofibril. While thick-filament lengths are essentially constant across muscles and species (∼1.65 μm), thin-filament lengths are highly variable both across species and across muscles of a single species. Here, we used a high-resolution immunofluorescence and image analysis technique (distributed deconvolution) to directly test the hypothesis that thin-filament lengths vary across human muscles. Using deltoid and pectoralis major muscle biopsies, we identified thin-filament lengths that ranged from 1.19 ± 0.08 to 1.37 ± 0.04 μm, based on tropomodulin localization with respect to the Z-line. Tropomodulin localized from 0.28 to 0.47 μm further from the Z-line than the NH(2)-terminus of nebulin in the various biopsies, indicating that human thin filaments have nebulin-free, pointed-end extensions that comprise up to 34% of total thin-filament length. Furthermore, thin-filament length was negatively correlated with the percentage of type 2X myosin heavy chain within the biopsy and shorter in type 2X myosin heavy chain-positive fibers, establishing the existence of a relationship between thin-filament lengths and fiber types in human muscle. Together, these data challenge the widely held assumption that human thin-filament lengths are constant. Our results also have broad relevance to musculoskeletal modeling, surgical reattachment of muscles, and orthopedic rehabilitation.

The menisci are important biomechanical components of the knee. We developed and validated a finite element model of meniscal replacement to assess the effect of surgical fixation technique on contact behavior and knee stability. The geometry of femoral and tibial articular cartilage and menisci was segmented from magnetic resonance images of a normal cadaver knee using MIMICS (Materialise, Leuven, Belgium). A finite element mesh was generated using HyperWorks (Altair Inc, Santa Ana, CA). A finite element solver (Abaqus v6.9, Simulia, Providence, RI) was used to compute contact area and stresses under axial loading and to assess stability (reaction force generated during anteroposterior translation of the femur). The natural and surgical attachments of the meniscal horns and peripheral rim were simulated using springs. After total meniscectomy, femoral contact area decreased by 26% with a concomitant increase in average contact stresses (36%) and peak contact stresses (33%). Replacing the meniscus without suturing the horns did little to restore femoral contact area. Suturing the horns increased contact area and reduced peak contact stresses. Increasing suture stiffness correlated with increased meniscal contact stresses as a greater proportion of tibiofemoral load was transferred to the meniscus. A small incremental benefit was seen of simulated bone plug fixation over the suture construct with the highest stiffness (50 N/mm). Suturing the rim did little to change contact conditions. The nominal anteroposterior stiffness reduced by 3.1 N/mm after meniscectomy. In contrast to contact area and stress, stiffness of the horn fixation sutures had a smaller effect on anteroposterior stability. On the other hand suturing the rim of the meniscus affected anteroposterior stability to a much larger degree. This model emphasizes the importance of the meniscus in knee biomechanics. Appropriate meniscal replacement fixation techniques are likely to be critical to the clinical success of meniscal replacement. While contact conditions are mainly sensitive to meniscus horn fixation, the stability of the knee under anteroposterior shear loads appeared to be more sensitive to meniscal rim fixation. This model may also be useful in predicting the effect of biomaterial mechanical properties and meniscal replacement shape on knee contact conditions.

Background/hypothesis: The arthritic glenoid is typically in retroversion and restoration to neutral version is recommended. While a method for measurement of glenoid version using axial computed tomography (CT) has been reported and has been widely accepted, its accuracy and reproducibility has not been established., Methods: In 33 patients scheduled for shoulder arthroplasty, glenoid version and maximum wear of the glenoid articular surface were measured with respect to the scapular body axis on 2-dimensional- (2D) CT slices as well as on 3-dimensional- (3D) reconstructed models of the same CT slices., Results: Clinical CT scans were axially aligned with the patient's torso but were almost never perpendicular to the scapular body. The average absolute error in version measured on the 2D-CT slice passing through the tip of the coracoid was 5.1 degrees (range, 0 - 16 degrees , P < .001). On high-resolution 3D-CT reconstructions, the location of maximum wear was most commonly posterior and was missed on the clinical 2D-CT slices in 52% of cases., Conclusion: Error in measuring version and depth of maximum wear can substantially affect the determination of the degree of correction necessary in arthritic glenoids. Accurately measuring glenoid version and locating the direction of maximum wear requires a full 3D-CT reconstruction and analysis., (Copyright 2010 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.)

Summary: The universally accepted method of measuring glenoid version to determine proper alignment of the glenoid component during total shoulder arthroplasty does not account for the complex and variable relationship of the glenoid vault with the scapular body. Existing evidence indicates that the glenoid and the scapular body development are controlled by independent genetic and biomechanical factors. This raises the question: How relevant is the relationship of the glenoid face to the scapular body? This review paper integrates our present understanding of the genetics of scapular development and congenital and neuromuscular conditions to generate insights into scapular morphology and biomechanics. Glenoid version as traditionally defined may have limited relevance when positioning the glenoid component during total shoulder arthroplasty. Further studies of soft-tissue and muscular balance are needed to fully understand the consequences of variations in glenoid version., Level of Evidence: Review.

Background: Because chondrocytes are responsible for articular cartilage matrix synthesis and maintenance, reduced chondrocyte viability could compromise graft survival, healing, and clinical outcome., Hypothesis: Typical forces used in osteochondral grafting reduce the viability of the chondrocytes in the graft., Study Design: Controlled laboratory study., Methods: Osteochondral grafting was performed in 4 fresh-frozen cadaver knees (n = 16 per knee). Impact force was measured during extrusion of the donor graft from the harvester into the recipient site, seating the graft flush with the articular surface of the surrounding cartilage using a tamp, and recessing the graft surface below the recipient articular surface. The magnitudes of forces measured during cadaver surgery (200, 400, and 800 N) were reproduced using a drop-tower apparatus on 80 fresh osteochondral grafts harvested from knee blocks provided by tissue banks. Cell viability and glycosaminoglycan release in media were measured at 48 hours after injury., Results: Forces were relatively low (range, 124-356 N) during graft extrusion from the harvester into the recipient defect or during flush seating (range, 191-418 N) of the graft. Attempts to recess the graft generated significantly greater force (range, 147-685; P < .01). When the donor graft length was 2 mm longer than the depth of the recipient hole, the mean impact force generated was even higher (range, 240-1114 N) than the force seen in a donor graft of equal length. No reduction in viability was seen at 200-N and 400-N impacts. However, a significant decrease in chondrocyte viability was seen in the group impacted with 800 N (only 50% of cells were viable, compared with 91% in the sham group; P < .01). Glycosaminoglycan levels in culture media did not correlate significantly with insertion force., Conclusion: Typical graft insertion forces did not significantly reduce chondrocyte viability. However, increased graft length relative to the depth of the recipient hole and attempts to recess the graft generated higher forces, which reduced chondrocyte viability., Clinical Relevance: Any theoretical benefits of cancellous bone compaction that may occur in grafts that are recessed or are longer than the recipient holes must be balanced against the potential reduction in chondrocyte viability.

Glenoid implant design and alignment are critical to the success of shoulder arthroplasty. Computer-aided design models of 3 glenoid implant designs (keel, standard pegs, and modified pegs) were virtually implanted into 3-dimensional computed tomography-reconstructed models of 40 normal scapulae. The incidence of perforation on 3-dimensional computed tomography preoperative templating varied from 8% to 18% for the 3 models. Malalignment of the implants in retroversion was better tolerated than anteversion and varied with implant design. Tolerance for medialization of the implant to correct for glenoid wear was limited (range, 0 degrees-18 degrees ) and varied with implant design. The modified peg design had the lowest incidence of perforation, the greatest tolerance for malalignment, and the ability to correct for glenoid wear effects. These results emphasize the need for accurate preoperative templating and for developing alignment guides or surgical navigation tools for shoulder arthroplasty and may be used to improve implant fixation designs.

Purpose: This prospective, randomized, double-blind study with a placebo group and 2 experimental groups evaluated the efficacy of continuous low-dose bupivacaine infiltration by infusion pump after arthroscopic rotator cuff repair., Methods: Sixty patients undergoing arthroscopic rotator cuff repair received a bolus injection in the subacromial space of 35 mL of 0.25% bupivacaine with 1:200,000 epinephrine at surgical closure and were randomized to 1 of 3 groups: 0.25% bupivacaine at 2 mL/hr (n = 20), 0.25% bupivacaine at 5 mL/hr (n = 20), or saline at 5 mL/hr (n = 20) via infusion pump into the subacromial space. Pain was evaluated using the visual analog scale (VAS) and narcotic consumption was measured until 48 hours after surgery and converted to dose equivalents (DE)., Results: Sixty patients used the infusion pump for a mean of 43.9 hours (range, 15.50 to 50.75 hrs). Mean total narcotic consumption, expressed in DEs, was 2.24 for the 2-mL group, 3.52 for the 5-mL group, and 2.32 for the placebo group. Mean pain score was 2.9 for the 2-mL group, 3.6 for the 5-mL group, and 3.3 for the placebo group. There were no differences in operating room time or infusion pump use time among groups. The 2-mL group had a nonsignificant trend toward less pain and lower narcotic consumption. The 5-mL group evidenced a nonsignificant trend toward more pain and higher narcotic consumption., Conclusions: This study neither supports nor refutes the use of infusion pumps. We hypothesized that the placebo group would experience greater pain than the 5-mL group; however, a nonsignificant trend toward the contrary occurred. A trend toward less pain in the 2-mL group was not significant., Level of Evidence: Level II, randomized controlled trial of therapeutic treatment that lacks statistical significance and narrow confidence intervals.

This study was designed to determine which subscapularis repair method performs best under fatigue loading. Fresh-frozen human cadaveric shoulders were used. A standard circumferential release was performed, including a rotator interval release and separation of the subscapularis from the anterior and inferior capsules. One of 3 methods was used to repair the subscapularis tendon: tendon-to-tendon, tendon-to-bone, or bone-to-bone using a buttress plate. The shoulder was mounted on a fatigue-testing machine, and the medial end of the subscapularis tendon was attached to a soft-tissue clamp. We initially tested each specimen for fatigue at 150 N for 500 cycles, then at 300 N for 2500 cycles. The failure rate of bone-to-bone and tendon-to-tendon repairs was significantly better than that of the tendon-to-bone repair. The bone-to-bone repair exhibited the best combination of repair strength and restoration of subscapularis length.

The goal of this article is to present a concise review of the current concepts of shoulder instability. This chapter supplements the radiologic assessment of glenohumeral instability, which follows this section.

Arthroscopic surgery of the shoulder is usually performed in the lateral decubitus or beachchair position. The modified beachchair position described here allows arthroscopic procedures to be performed as in the lateral position yet maintains a semiupright orientation and permits conversion to open procedures as in the beachchair position. The results of this technique are reported for 50 consecutive patients with a variety of diagnoses. This modified beachchair position was found to be quickly and easily accomplished with a minimum of special equipment.

Purpose: The purpose of this study was to determine whether continuous infiltration of a local anesthetic into the surgical wound for 48 hours will diminish the need for narcotics and improve the postoperative pain experience for patients undergoing anterior cruciate ligament (ACL) reconstruction using a patellar tendon autograft., Type of Study: Prospective, randomized, double-blind study with a placebo and an experimental group., Methods: Twenty-six patients were randomly assigned to receive either normal saline (placebo) or bupivacaine (experimental) for 48 hours. Both groups received a single intra-articular bolus injection of 35 mL of 0.25% bupivacaine and 5 mg. of morphine at the conclusion of surgery. The placebo group received an infusion of 2 mL/h of normal saline and the experimental group received an infusion of 2 mL/h of 0.25% bupivacaine, both for 48 hours. The anesthetic was infused using a disposable elastomeric pump (Baxter Healthcare, Deerfield, IL). Patients were evaluated using a pain and pain relief assessment questionnaire and visual analogue scale (VAS). Narcotic consumption was also documented. The pump was discontinued either by the patient at home or by a physical therapist., Results: There was a statistically significant (P <.05) difference in VAS pain and pain relief scores reported by patients receiving the infusion of 0.25% bupivacaine. Patients in the treatment group also consumed 37% less narcotics than the placebo group. The operating room time, tourniquet time, weight, and age of this population were similar in the 2 groups. There were no complications with the catheter technique., Conclusion: This report of a new technique suggests that surgical knee patients receiving local anesthetic infusion postoperatively experience less pain and require less narcotics. The disposable pump allowed administration of the medication on an outpatient basis.

Chondrocytes undergo apoptosis in response to mechanical injury in vitro. The current clinical study correlates arthroscopic and magnetic resonance imaging results with biopsy specimens of cartilage from patients with knee injury. Twenty patients were evaluated at a mean 2.7 months after acute knee injury. The mean age of the patients was 32 years and the mean weight was 83 kg. Cartilage lesions were graded separately on magnetic resonance images and arthroscopy in a blinded manner. During arthroscopy, a 1.8 mm diameter biopsy specimen was obtained from the edge of cartilage lesion. The biopsy specimen underwent histologic examination by safranin O staining and detection of chondrocyte apoptosis by the presence of deoxyribonucleic acid fragmentation. There was a positive correlation in 50% (10 of 20) when the presence or absence of cartilage lesions by magnetic resonance imaging was correlated with arthroscopy. All cases of partial thickness or full-thickness cartilage loss that were seen by arthroscopy also were detected by magnetic resonance images. Apoptotic cells were significantly more numerous in biopsy specimens from lesions compared with control biopsy specimens. The findings of reduced cell viability attributable to apoptosis may have profound implications for cartilage repair. This opens potential therapeutic avenues for the treatment of posttraumatic cartilage lesions through apoptosis prevention.

Exertional compartment syndrome is characterized by intracompartmental pressures that rise transiently following repetitive motion or exercise, thereby producing temporary, reversible ischemia, pain, weakness, and, occasionally, neurologic deficits. The exact cause or pathogenesis remains unclear; a disturbance of microvascular flow caused by elevated intramuscular pressure leads to tissue ischemia, depletion of high-energy phosphate stores, and cellular acidosis. Anatomic contributing factors may include a limited compartment size, increased intracompartmental volume, constricted fascia, loss of compartment elasticity, poor venous return, or increased muscle bulk. The diagnosis is suspected based on history and confirmed with physical examination and intramuscular pressure evaluation before and after exercise (stress test). Differential diagnosis includes claudication or other vascular abnormalities, myositis, tendinitis, periostitis, chronic strains or sprains, stress fracture, other compression or systemic neuropathies, and cardiac abnormalities with angina or referred extremity pain. Initial treatment includes activity modification; refractory symptoms can be managed with elective fasciotomy.

In this study, the dependence on beam direction of the echocardiographically derived fractional shortening of the left ventricular minor axis was evaluated. A directionally oriented, steerable cursor was used to select M-mode lines from a 2-dimensional image at the chordal level. Seven M-mode traces were derived from each image, 1 along the true ventricular meridian and 3 at known deviations on either side of the meridian. M-mode traces, thus derived, all appeared acceptable for measuring wall or cavity dimensions. Results indicate a progressive increase in shortening fraction (p less than 0.05) for deviations more than 25% of the distance between the meridian and the lateral or medial papillary muscle heads. Decreases in left ventricular dimensions in diastole and systole with progressive deviation from the meridian accounted for the decrease in shortening fraction. Spatial orientation is required for reproducible shortening fraction measurements.