ChatGPT-4 Performs Clinical Information Retrieval Tasks Utilizing Consistently More Trustworthy Resources Than Does Google Search for Queries Concerning the Latarjet Procedure.

PURPOSE: To assess the ability for ChatGPT-4, an automated Chatbot powered by artificial intelligence (AI), to answer common patient questions concerning the Latarjet procedure for patients with anterior shoulder instability and compare this performance to Google Search Engine. METHODS: Using previously validated methods, a Google search was first performed using the query "Latarjet." Subsequently, the top ten frequently asked questions (FAQs) and associated sources were extracted. ChatGPT-4 was then prompted to provide the top ten FAQs and answers concerning the procedure. This process was repeated to identify additional FAQs requiring discrete-numeric answers to allow for a comparison between ChatGPT-4 and Google. Discrete, numeric answers were subsequently assessed for accuracy based on the clinical judgement of two fellowship-trained sports medicine surgeons blinded to search platform. RESULTS: Mean (±standard deviation) accuracy to numeric-based answers were 2.9±0.9 for ChatGPT-4 versus 2.5±1.4 for Google (p=0.65). ChatGPT-4 derived information for answers only from academic sources, which was significantly different from Google Search Engine (p=0.003), which used only 30% academic sources and websites from individual surgeons (50%) and larger medical practices (20%). For general FAQs, 40% of FAQs were found to be identical when comparing ChatGPT-4 and Google Search Engine. In terms of sources used to answer these questions, ChatGPT-4 again used 100% academic resources, while Google Search Engine used 60% academic resources, 20% surgeon personal websites, and 20% medical practices (p=0.087). CONCLUSION: ChatGPT-4 demonstrated the ability to provide accurate and reliable information about the Latarjet procedure in response to patient queries, using multiple academic sources in all cases. This was in contrast to Google Search Engine, which more frequently used single surgeon and large medical practice websites. Despite differences in the resources accessed to perform information retrieval tasks, the clinical relevance and accuracy of information provided did not significantly differ between ChatGPT-4 and Google Search Engine.

Outcomes after débridement, antibiotics, and implant retention for prosthetic joint infection in shoulder arthroplasty.

BACKGROUND: Patients who undergo total shoulder arthroplasty usually have excellent long-term outcomes. However, a subset of patients is diagnosed with a prosthetic joint infection (PJI) requiring revision procedures and prolonged recovery. The purpose of this study was to evaluate rates of recurrent shoulder PJI in patients undergoing débridement, antibiotics, and implant retention (DAIR), single-stage revision, and 2-stage revision. We also sought to compare outcomes and complications across procedures. METHODS: Retrospective chart review was conducted for patients diagnosed with PJI after primary shoulder arthroplasty between January 2010 and August 2021. Patients were included if they underwent treatment with DAIR, single-stage revision, or 2-stage revision. Demographic information, surgical details, complications, laboratory data, postoperative antibiotic regimen, and infectious pathogen were collected. Postoperative patient-reported outcomes were collected: American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, Single Assessment Numeric Evaluation, Shoulder Activity Scale, and PROMIS Upper Extremity. Chi-square, t test, and 1-way analysis of variance were used as appropriate to evaluate each factor. RESULTS: Sixty-five patients were included in the study, 26% treated with DAIR, 9% treated with single-stage revision, and 65% treated with 2-stage revision. There were no significant differences in patient comorbidities. Patients undergoing DAIR were diagnosed significantly earlier than those undergoing single- and 2-stage revision procedures (12.6 ± 22.9 months vs. 49.6 ± 48.4 vs. 25.0 ± 26.6, P = .010). Recurrent PJI was noted in 23.1% of patients: 29.4% of DAIR patients, no single-stage patients, and 23.8% of 2-stage patients (P = .330). Patients undergoing 2-stage revision with treatment failure had a significantly higher Elixhauser Comorbidity Index (0.2 ± 3.7 vs. 3.7 ± 3.9, P = .027). There was no significant difference in patient-reported outcomes across groups. CONCLUSION: Patients undergoing treatment of shoulder PJI with DAIR did not have an increased rate of reinfection compared with single-stage and 2-stage revision procedures. Patients treated with DAIR were diagnosed with PJI significantly earlier than those undergoing single-stage and 2-stage revision procedures. There was no difference in complication rates between groups. This information adds to the body of work detailing outcomes after DAIR for shoulder PJI and provides encouraging data for use in this patient population. Future studies with a larger sample size may be conducted to further investigate specific pathogens, infection timelines, and antibiotic regimens that reduce the risk of treatment failure.

Predictors of dislocations after reverse shoulder arthroplasty: a study by the ASES complications of RSA multicenter research group.

BACKGROUND: Instability after reverse shoulder arthroplasty (RSA) is one of the most frequent complications and remains a clinical challenge. Current evidence is limited by small sample size, single-center, or single-implant methodologies that limit generalizability. We sought to determine the incidence and patient-related risk factors for dislocation after RSA, using a large, multicenter cohort with varying implants. METHODS: A retrospective, multicenter study was performed involving 15 institutions and 24 American Shoulder and Elbow Surgeons members across the United States. Inclusion criteria consisted of patients undergoing primary or revision RSA between January 2013 and June 2019 with minimum 3-month follow-up. All definitions, inclusion criteria, and collected variables were determined using the Delphi method, an iterative survey process involving all primary investigators requiring at least 75% consensus to be considered a final component of the methodology for each study element. Dislocations were defined as complete loss of articulation between the humeral component and the glenosphere and required radiographic confirmation. Binary logistic regression was performed to determine patient predictors of postoperative dislocation after RSA. RESULTS: We identified 6621 patients who met inclusion criteria with a mean follow-up of 19.4 months (range: 3-84 months). The study population was 40% male with an average age of 71.0 years (range: 23-101 years). The rate of dislocation was 2.1% (n = 138) for the whole cohort, 1.6% (n = 99) for primary RSAs, and 6.5% (n = 39) for revision RSAs (P < .001). Dislocations occurred at a median of 7.0 weeks (interquartile range: 3.0-36.0 weeks) after surgery with 23.0% (n = 32) after a trauma. Patients with a primary diagnosis of glenohumeral osteoarthritis with an intact rotator cuff had an overall lower rate of dislocation than patients with other diagnoses (0.8% vs. 2.5%; P < .001). Patient-related factors independently predictive of dislocation, in order of the magnitude of effect, were a history of postoperative subluxations before radiographically confirmed dislocation (odds ratio [OR]: 19.52, P < .001), primary diagnosis of fracture nonunion (OR: 6.53, P < .001), revision arthroplasty (OR: 5.61, P < .001), primary diagnosis of rotator cuff disease (OR: 2.64, P < .001), male sex (OR: 2.21, P < .001), and no subscapularis repair at surgery (OR: 1.95, P = .001). CONCLUSION: The strongest patient-related factors associated with dislocation were a history of postoperative subluxations and having a primary diagnosis of fracture nonunion. Notably, RSAs for osteoarthritis showed lower rates of dislocations than RSAs for rotator cuff disease. These data can be used to optimize patient counseling before RSA, particularly in male patients undergoing revision RSA.

No Difference in Complication or Reoperation Rates Between Arthroscopic and Open Debridement for Lateral Epicondylitis: A National Database Study.

PURPOSE: To compare complication rates and 5-year reoperation rates between open debridement (OD) and arthroscopic debridement (AD) for lateral epicondylitis. METHODS: The PearlDiver MUExtr database (2010-2019) was reviewed for patients diagnosed with lateral epicondylitis (queried by International Classification of Diseases, Ninth Revision and International Classification of Diseases, Tenth Revision [ICD-10] codes) undergoing OD or AD of the common extensor tendon without repair (queried by Current Procedural Terminology codes). Patients were stratified into 2 cohorts: those who underwent AD and those who underwent OD. Nonoperative treatment modalities were reported for both groups within 1 year before index procedure. The rates of 90-day postoperative complications were compared, and multivariate logistic regression analysis was used to identify risk factors for complications. The 5-year reoperation rates, using laterality-specific ICD-10 codes, were also compared between the 2 groups. RESULTS: In total, 19,280 patients (OD = 17,139, AD = 2,141) were analyzed in this study. The most common nonoperative treatments for patients who underwent OD or AD were corticosteroid injections (49.5% vs 43.2%), physical therapy (24.8% vs 25.7%), bracing (2.8% vs 3.2%), and platelet-rich plasma injections (1.3% vs 1.0%). There were no significant differences in radial nerve injuries, hematomas, surgical site infections, wound dehiscence, and sepsis events between the 2 procedures (P = .50). The 5-year reoperation rate was not significantly different between the AD (5.0%) and OD (3.9%) cohorts (P = .10). CONCLUSIONS: For lateral epicondylitis, both AD and OD of the extensor carpi radialis brevis (without repair) were found to have low rates of 90-day adverse events, with no significant differences between the 2 approaches. Similarly, the 5-year reoperation rate was low and not statistically different for those treated with OD or AD. LEVEL OF EVIDENCE: Level III, cross-sectional study.

Survival analyses and their applications in orthopaedics.

Survival analyses are a powerful statistical tool used to analyse data when the outcome of interest involves the time until an event. There is an array of models fit for this goal; however, there are subtle differences in assumptions, as well as a number of pitfalls, that can lead to biased results if researchers are unaware of the subtleties. As larger amounts of data become available, and more survival analyses are published every year, it is important that healthcare professionals understand how to evaluate these models and apply them into their practice. Therefore, the purpose of this study was to present an overview of survival analyses, including required assumptions and important pitfalls, as well as examples of their use within orthopaedic surgery.

How accurate are positive preoperative aspiration culture results in shoulder periprosthetic joint infection? A concordance study.

BACKGROUND: The concordance between preoperative synovial fluid cultures and intraoperative tissue cultures for identifying pathogenic microorganisms in shoulder periprosthetic joint infection (PJI) remains poorly understood. The purpose of our study was to examine the diagnostic accuracy of positive synovial fluid culture results in early pathogen identification for shoulder PJI. METHODS: A total of 35 patients who met the Musculoskeletal Infection Society criteria for PJI following primary anatomic or reverse arthroplasty and the study inclusion criteria were identified retrospectively from a single institution (multiple surgeons) from January 2011 to June 2021. The inclusion criteria required a positive preoperative intra-articular synovial fluid sample within 90 days analyzed within the same institution and intraoperative tissue cultures at the time of arthrotomy. Concordance was determined when the organism(s) identified from the aspirate correlated with the intraoperative specimens. RESULTS: Overall concordance was identified in 28 of 35 patients (80%), with similar concordance for anatomic (21 of 24, 88%) and reverse (7 of 11, 64%) shoulder arthroplasties (P = .171). Culture discordance occurred in 7 of 35 patients (20%): of these, 5 (14%) had no corresponding intraoperative culture growth whereas 2 (6%) had polymicrobial intraoperative cultures. Monomicrobial Cutibacterium acnes PJI cases were the most common (24 of 35, 69%) and had an overall concordance rate of 79%. Of 5 discordant C acnes patients, 2 had polymicrobial intraoperative cultures and 3 had negative intraoperative culture results; all the patients with negative intraoperative culture results had received antibiotics between the time of aspiration and surgery. Considered separately, concordance in patients who had a positive aspirate finding for C acnes and did not receive antibiotics prior to surgery was 19 of 21 (90%), with a sensitivity of 100% (95% confidence interval, 82%-100%) and a corresponding positive predictive value of 0.91 (95% confidence interval, 58%-93%). CONCLUSION: Preoperative positive aspiration culture results demonstrated favorable sensitivity and specificity when compared with intraoperative tissue cultures in identifying pathogenic microorganisms in shoulder PJI patients. These findings are congruent with literature from hip and knee arthroplasty. Ultimately, confidence in the accuracy of positive preoperative aspiration culture results in shoulder PJI may facilitate the development of early, targeted treatment strategies while directing patient expectations and risk.

How common is nerve injury after reverse shoulder arthroplasty? A systematic review.

BACKGROUND: Nerve injury following reverse shoulder arthroplasty (RSA) is a known risk factor with wide ranging incidences reported. This systematic review evaluates the overall incidence of nerve injury following primary and revision RSA and summarizes the characteristics of the nerve injuries reported in the current literature. METHODS: A systematic review was performed using separate database searches (Pubmed, Embase, Web of Science, Cochrane) following the PRISMA guidelines. Search criteria included the title terms "reverse shoulder," "reverse total shoulder," "inverted shoulder," and "inverted total shoulder" with publication dates ranging from 01/01/2010 to 01/01/2022. Studies that reported neurological injuries and complications were included and evaluated for primary RSA, revision RSA, number of nerve injuries, and which nerves were affected. RESULTS: After exclusion, our systematic review consisted of 188 articles. A total of 40,146 patients were included, with 65% female. The weighted mean age was 70.3 years. The weighted mean follow-up was 35.4 months. The rate of nerve injury after RSA was 1.3% (510 of 40,146 RSAs). The rate of injury was greater in revision RSA compared to primary RSA (2.4% vs. 1.3%). Nerve injury was most common in RSAs done for a primary diagnosis of acute proximal humerus fracture (4.0%), followed by cuff tear arthropathy (3.0%), DJD (2.6%), and inflammatory arthritis (1.7%). Massive rotator cuff tears and post-traumatic arthritis cases had the lowest nerve injury rates (1.0% and 1.4%, respectively). The axillary nerve was the most commonly reported nerve that was injured in both primary and revision RSA (0.6%), followed by the ulnar nerve (0.26%) and median nerve (0.23%). Brachial plexus injury was reported in 0.19% of overall RSA cases. CONCLUSION: Based on current English literature, nerve injuries occur at a rate of 1.3% after primary RSA compared with 2.4% after revision RSA. The most common nerve injury was to the axillary nerve (0.64%), with the most common operative diagnosis associated with nerve injury after RSA being acute proximal humerus fracture (4.0%). Surgeons should carefully counsel patients prior to surgery regarding the risk of nerve injury.

Artificial intelligence for automated identification of total shoulder arthroplasty implants.

BACKGROUND: Accurate and rapid identification of implant manufacturer and model is critical in the evaluation and management of patients requiring revision total shoulder arthroplasty (TSA). Failure to correctly identify implant designs in these circumstances may lead to delay in care, unexpected intraoperative challenges, increased morbidity, and excess health care costs. Deep learning (DL) permits automated image processing and holds the potential to mitigate such challenges while improving the value of care rendered. The purpose of this study was to develop an automated DL algorithm to identify shoulder arthroplasty implants from plain radiographs. METHODS: A total of 3060 postoperative images from patients who underwent TSA between 2011 and 2021 performed by 26 fellowship-trained surgeons at 2 independent tertiary academic hospitals in the Pacific Northwest and Mid-Atlantic Northeast were included. A DL algorithm was trained using transfer learning and data augmentation to classify 22 different reverse TSA and anatomic TSA prostheses from 8 implant manufacturers. Images were split into training and testing cohorts (2448 training and 612 testing images). Optimized model performance was assessed using standardized metrics including the multiclass area under the receiver operating characteristic curve (AUROC) and compared with a reference standard of implant data from operative reports. RESULTS: The algorithm classified implants at a mean speed of 0.079 seconds (±0.002 seconds) per image. The optimized model discriminated between 8 manufacturers (22 unique implants) with AUROCs of 0.994-1.000, accuracy of 97.1%, and sensitivities between 0.80 and 1.00 on the independent testing set. In the subset of single-institution implant predictions, a DL model identified 6 specific implants with AUROCs of 0.999-1.000, accuracy of 99.4%, and sensitivity >0.97 for all implants. Saliency maps revealed key differentiating features across implant manufacturers and designs recognized by the algorithm for classification. CONCLUSION: A DL model demonstrated excellent accuracy in identifying 22 unique TSA implants from 8 manufacturers. This algorithm may provide a clinically meaningful adjunct in assisting with preoperative planning for the failed TSA and allows for scalable expansion with additional radiographic data and validation efforts.

Factors associated with humeral stem revision in anatomic to reverse total shoulder arthroplasty revision.

BACKGROUND: Recent advances in implant technology have allowed for modular or platform humeral stem insertion during initial anatomic total shoulder arthroplasty (TSA). These systems allow for humeral stem retention during conversion to reverse TSA (RTSA). However, some patients still require humeral stem revision when undergoing revision to RTSA. The purpose of this study was to evaluate the association between patient-specific factors and radiographic parameters with humeral stem revision vs. retention during conversion from TSA to RTSA. METHODS: Retrospective chart review was conducted for patients who underwent a revision TSA to RTSA between January 2010 and May 2022 at a single institution. Patients were included if their prosthesis included a convertible humeral stem. Patient demographic information, surgical details, and postoperative outcomes and complications were collected. Radiographic parameters were measured by 2 graders on radiographs taken prior to the revision procedure. The need for humeral stem revision and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores (preoperative and 2 years) were also noted. Statistical analysis was performed using chi-square test for categorical variables and t test for continuous variables. RESULTS: One hundred seven patients were included, with 52 undergoing humeral stem revision. Patients were revised an average of 51.0 ± 54 months after primary TSA. Younger patient age (63.6 vs. 68.5 years, P = .017) and use of a lateralized glenosphere (1.6 mm vs. 0.4 mm, P < .001) were significantly associated with need for humeral stem revision. Glenoid to humeral head cut distance (28.3 mm vs. 26.3 mm, P = .076) approached significant association with the need for humeral stem revision. All other measurements were not associated with the need for humeral stem revision. Improvement of ASES scores at 2 years' follow-up was higher in the nonrevised group (increase of 33.4 points) than the revision group (23.3), but this did not reach significance (P = .149). Estimated blood loss and surgical time were significantly higher in the stem revision group than the non-revised group (P = .048 and P < .001, respectively). CONCLUSION: Younger patients and those receiving a lateralized glenosphere were more likely to undergo humeral stem revision during conversion from TSA to RTSA. Glenoid to the humeral head cut distance should be studied further as a potential indication for humeral stem revision, as it correlates with the space available for a revision implant. This information can guide surgeons with preoperative planning for a revision arthroplasty.

Risk factors of acromial and scapular spine stress fractures differ by indication: a study by the ASES Complications of Reverse Shoulder Arthroplasty Multicenter Research Group.

BACKGROUND: Both patient and implant related variables have been implicated in the incidence of acromial (ASF) and scapular spine fractures (SSF) following reverse shoulder arthroplasty (RSA); however, previous studies have not characterized nor differentiated risk profiles for varying indications including primary glenohumeral arthritis with intact rotator cuff (GHOA), rotator cuff arthropathy (CTA), and massive irreparable rotator cuff tear (MCT). The purpose of this study was to determine patient factors predictive of cumulative ASF/SSF risk for varying preoperative diagnosis and rotator cuff status. METHODS: Patients consecutively receiving RSA between January 2013 and June 2019 from 15 institutions comprising 24 members of the American Shoulder and Elbow Surgeons (ASES) with primary, preoperative diagnoses of GHOA, CTA and MCT were included for study. Inclusion criteria, definitions, and inclusion of patient factors in a multivariate model to predict cumulative risk of ASF/SSF were determined through an iterative Delphi process. The CTA and MCT groups were combined for analysis. Consensus was defined as greater than 75% agreement amongst contributors. Only ASF/SSF confirmed by clinical and radiographic correlation were included for analysis. RESULTS: Our study cohort included 4764 patients with preoperative diagnoses of GHOA, CTA, or MCT with minimum follow-up of 3 months (range: 3-84). The incidence of cumulative stress fracture was 4.1% (n = 196). The incidence of stress fracture in the GHOA cohort was 2.1% (n = 34/1637) compared to 5.2% (n = 162/3127) (P < .001) in the CTA/MCT cohort. Presence of inflammatory arthritis (odds ratio [OR] 2.90, 95% confidence interval [CI] 1.08-7.78; P = .035) was the sole predictive factor of stress fractures in GHOA, compared with inflammatory arthritis (OR 1.86, 95% CI 1.19-2.89; P = .016), female sex (OR 1.81, 95% CI 1.20-2.72; P = .007), and osteoporosis (OR 1.56, 95% CI 1.02-2.37; P = .003) in the CTA/MCT cohort. CONCLUSION: Preoperative diagnosis of GHOA has a different risk profile for developing stress fractures after RSA than patients with CTA/MCT. Though rotator cuff integrity is likely protective against ASF/SSF, approximately 1/46 patients receiving RSA with primary GHOA will have this complication, primarily influenced by a history of inflammatory arthritis. Understanding risk profiles of patients undergoing RSA by varying diagnosis is important in counseling, expectation management, and treatment by surgeons.

The role of the long head of the biceps tendon in posterior shoulder stabilization during forward flexion.

BACKGROUND: The role of the long head of the biceps tendon (LHBT) in glenohumeral stability is not fully understood. Most objects are lifted in the sagittal plane with forward flexion, which stresses the posterior aspect of the unconstrained glenohumeral joint. Determining the mechanism by which the shoulder maintains stability with functional motions is important to understanding the pathoanatomy of degenerative shoulders. Our hypothesis was that the LHBT resists posterior translation of the humeral head (HH) during forward flexion by tensioning the posterior capsuloligamentous complex. METHODS: Ten fresh-frozen cadaveric shoulders were tested using an established shoulder simulator that loads the LHBT, rotator cuff, and deltoid tendons through a system of pulleys. A motion tracking system recorded glenohumeral translations with an accuracy of ±0.2 mm. In each subject, the scapula was fixed and the humerus was tested in 6 positions: 30° and 60° of glenohumeral forward flexion at (1) maximum internal rotation (IR), (2) neutral rotation, and (3) maximum external rotation (ER). The deltoid was loaded with 100 N, and the infraspinatus and subscapularis were loaded with 22 N each. The difference in glenohumeral translation was calculated at each position comparing the LHBT loaded with 45 N or unloaded. RESULTS: At 30° of glenohumeral forward flexion, unloading the LHBT increased HH posterior translation by 2.5 mm (±0.9 mm; P < .001), 1.7 mm (±1.0 mm; P < .001), and 1.0 mm (±0.9 mm; P = .01) at maximum ER, neutral rotation, and maximum IR, respectively. At 60° of glenohumeral forward flexion, unloading the LHBT increased HH posterior translation by 2.8 mm (±1.2 mm; P < .001), 2.4 mm (±1.6 mm; P < .001), and 1.7 mm (±1.4 mm; P < .001) at maximum ER, neutral rotation, and maximum IR, respectively. CONCLUSION: LHBT loading resists posterior translation of the HH during forward flexion. These data support the role of the LHBT as a posterior stabilizer of the shoulder, specifically when a person is carrying objects in front of them. Further work is needed to determine if unloading the LHBT, as is done with biceps tenotomy or tenodesis, may eventually lead to posterior labral pathology, or to the posterior glenoid wear commonly seen with osteoarthritis.

Outcomes of shoulder arthroplasty by year of index procedure: are we getting better?

BACKGROUND: The purpose of this study was to determine whether postoperative patient-reported outcomes improved over time following anatomic total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (RTSA). METHODS: We performed a retrospective analysis of prospectively collected patient-reported outcomes from our institution's registry between 2008 and 2018 (N = 1899). American Shoulder and Elbow Surgeons (ASES) scores at a minimum of 2 years postoperatively were required. Univariable linear models were used to test the association between year of surgery and improvement in ASES scores at 2- and 5-year follow-up, as well as any association with age, sex, primary or revision surgery, hand dominance, American Society of Anesthesiologists classification, rotator cuff status, primary diagnosis, and Walch classification. Multivariable models were created to analyze ASES score improvement by index year while controlling for significant factors. RESULTS: In the univariable analysis, 5-year ASES difference scores increased each year by a mean of 1.65 (P < .001; 95% confidence interval [CI], 0.75-2.55) for TSA, 2.50 (P = .014; 95% CI, 0.52-4.49) for RTSA, and 1.64 (P < .001; 95% CI, 0.81-2.47) for the overall population. Patient sex, American Society of Anesthesiologists classification, rotator cuff status, primary diagnosis, Walch classification, and revision procedures were also significant factors affecting ASES scores. On multivariable analysis controlling for these factors, 5-year ASES difference scores were still significantly associated with year of surgery, increasing each year by a mean of 2.20 (P < .001; 95% CI, 0.91-3.50) for TSA, 4.83 (P < .001; 95% CI, 1.17-8.49) for RTSA, and 1.66 (P < .001; 95% CI, 0.81-2.51) for the entire population. CONCLUSION: Both anatomic TSA and RTSA patients reported increasing ASES difference scores at 5-year follow-up as time passed. These findings may indicate that advances in shoulder arthroplasty have resulted in better patient outcomes over time. Further research is needed to clarify which factors influence improvements in outcomes, particularly for revision procedures.

Biomechanical analysis of latissimus dorsi, pectoralis major, and pectoralis minor transfers in subscapularis-deficient shoulders.

BACKGROUND: Irreparable subscapularis (SSc) tears alter the dynamic force coupling of the shoulder, resulting in pain, weakness, and impaired shoulder function. Pectoralis major (Pma), pectoralis minor (Pmi), and latissimus dorsi (LD) transfers are treatment options for irreparable SSc tears, but clinical outcomes vary. The purpose of this study was to compare the biomechanical properties of Pma, Pmi, and LD transfers in an SSc-deficient shoulder using a computational model. METHODS: A computer shoulder model was used to investigate the moment arms of Pma, Pmi, and LD tendon transfers compared with an intact SSc. Nine computed tomography scans from subjects without osteoarthritis were used. Virtual Pma, Pmi, and LD transfers were performed to the upper border of the SSc insertion site on the lesser tuberosity of the humerus. Muscle moment arms were computed for functional motions of 0°-80° of internal rotation with the arm in 20° and 90° of shoulder abduction and 0°-150° of shoulder abduction. The results were compared with those of the native SSc moment arms. A repeated-measures analysis of variance was then performed to determine significant differences. RESULTS: Internal rotation moment arms of the transferred Pma and Pmi decreased significantly after 30° and 40° of internal rotation compared with the SSc moment arm of the intact shoulder, whereas the moment arm of LD transfer more closely mimicked that of the native SSc through 0°-80° of internal rotation. All 3 tendon transfer configurations demonstrated weak abductive moment arms (7.6-8.0 mm), comparable to the intact SSc (7.8 mm) but significantly lower than the intact adductive moment arms of the native Pma and LD (26.8 mm and 28.2 mm, respectively). CONCLUSION: LD transfer most closely approximates the native SS regarding internal rotation moment arms. However, LD transfer also showed a reduction in adductive moment arms.

Biomechanical comparison of 3 latissimus dorsi transfer sites for reverse total shoulder arthroplasty in the absence of teres minor.

BACKGROUND: Reverse total shoulder arthroplasty is often performed to treat rotator cuff tear arthropathy with irreparable rotator cuff tears. Patients with full-thickness tears involving the posterior cuff and teres minor specifically lose active external rotation of the humerus, limiting activities of daily living. A latissimus dorsi transfer has been described as one potential solution, but few studies have compared different latissimus dorsi transfer sites. This study assesses the biomechanics of 3 latissimus dorsi transfer sites, examining external rotation, deltoid muscle forces, and force across the glenoid for specific activities. METHODS: The Newcastle Shoulder Model was modified to include a Delta III reverse shoulder arthroplasty and was used to model the effects of 3 latissimus dorsi transfer sites-anterior, posterolateral, and posterodistal-in the setting of teres minor deficiency. The latissimus dorsi was represented by 5 muscle elements approximating anatomic fascicle divisions. Kinematic data sets representing common activities were input into the model, allowing calculation of muscle forces and glenoid loads. RESULTS: Each of the 3 latissimus dorsi transfer sites demonstrated a change of moment arm from internal to external rotation with increased magnitude. Average maximum deltoid muscle forces and glenoid loading across all motions decreased for each of the 3 transfer sites, with the greatest decreased force noted for the posterior deltoid. This decrease in deltoid force and glenoid loading was significantly greater with the anterior and posterolateral transfer sites, relative to the posterodistal site. DISCUSSION: Latissimus dorsi transfer to all 3 sites in the setting of reverse total shoulder arthroplasty and posterior rotator cuff deficiency resulted in large external rotation moment arms. The transferred latissimus dorsi shared the external rotation load and resulted in decreased deltoid forces and glenoid loading with very small differences between the 3 transfer sites. The posterodistal location reduced deltoid force and glenoid loading to a lower degree compared with other sites, but it also showed that it did not alter the tendon length compared with the native shoulder.

Biomechanical analysis of anterior stability after 15% glenoid bone loss: comparison of Bankart repair, dynamic anterior stabilization, dynamic anterior stabilization with Bankart repair, and Latarjet.

BACKGROUND: Dynamic anterior shoulder stabilization (DAS) with Bankart repair is a recently described stabilization technique thought to be more robust than an isolated Bankart repair while avoiding many coracoid transfer-related complications and technical demands. DAS involves transfer of the long head biceps through a subscapularis split to the anterior glenoid to create a sling effect. We hypothesize that DAS with Bankart repair will restore anterior stability in a human-cadaveric model with subcritical (15%) glenoid bone loss. METHODS: Eight cadaveric shoulders were tested using an established shoulder simulator to record glenohumeral translations with an accuracy of ±0.2 mm. Shoulders were tested in 5 states-intact soft tissues, Bankart defect with 15% bone loss, isolated Bankart repair, DAS with Bankart repair, isolated DAS, and Latarjet. A 45 N anterior force was applied through the pectoralis major tendon, and translation of the humeral head was recorded and compared with repeated measures analysis of variance. RESULTS: The anterior translation in the intact (native) glenoid was 4.7 mm at neutral position and 4.6 mm at 45° external rotation. Anterior translation significantly increased after introducing a Bankart defect with 15% glenoid bone loss to 9.1 mm (neutral, P = .002) and 9.5 mm (45° external rotation, P < .001). All repair conditions showed a significant decrease in anterior translation relative to Bankart defect. DAS with Bankart repair decreased anterior translation compared with the Bankart defect: 2.7 mm (neutral, P < .001) and 2.1 mm (45° external rotation, P < .001). DAS with Bankart repair significantly decreased anterior translation compared with the isolated Bankart repair (2.7 mm vs. 4.7 mm, P = .023) and the isolated DAS (2.7 mm vs. 4.3 mm, P = .041) in neutral position. The Latarjet procedure resulted in the greatest reduction in anterior translation compared with the Bankart defect: 1.2 mm (neutral, P < .001) and 1.9 mm (45° external rotation, P < .001). CONCLUSIONS: DAS with Bankart repair is a viable alternative to restore anterior glenohumeral stability with a 15% glenoid defect at a greater degree than either DAS or Bankart repair alone. The Latarjet procedure was the most effective in reducing anterior translation but restrained the anterior translation significantly more than the native glenoid.

Minimum 15-year follow-up for clinical outcomes of arthroscopic rotator cuff repair.

BACKGROUND AND HYPOTHESIS: Arthroscopic rotator cuff repair surgery is one of the most common shoulder procedures performed in the United States. Although several studies have shown considerable symptomatic relief in the short term following surgery, a relatively high rate of recurrent defects has led surgeons to question the long-term durability of this operation. We hypothesized that outcomes at a minimum of 15 years of follow-up in patients who underwent all-arthroscopic rotator cuff repair would be maintained and would remain significantly improved compared with the preoperative status. METHODS: All-arthroscopic rotator cuff repairs were performed in 193 patients from 2003 to 2005. Patient-reported outcomes were collected preoperatively and at 1, 2, 5, and ≥15 years postoperatively. The primary outcome was the American Shoulder and Elbow Surgeons (ASES) score. Secondary outcomes included Single Assessment Numeric Evaluation (SANE), Shoulder Activity Scale (SAS), visual analog scale, and Patient-Reported Outcomes Measurement Information System (PROMIS)-Upper Extremity (UE) scores. Patient demographic characteristics, revision surgical procedures, and complications were recorded. Generalized estimating equations were used to model scores over time, and multiple comparisons between time points were performed using Tukey adjustment. RESULTS: This study included 60 patients with a mean follow-up period of 16.5 years (range, 15.8-17.7 years). The mean ASES score improved from 60.2 ± 18.8 preoperatively to 93.0 ± 9.4 at ≥15 years (P < .0001). The mean visual analog scale pain score decreased from 4.1 ± 0.7 preoperatively to 0.7 ± 0.3 at ≥15 years (P < .0001). The average SANE, SAS, and PROMIS-UE scores at ≥15 years were 87.8 ± 14.8, 8.8 ± 4.3, and 49.6 ± 10.2, respectively. Of 60 patients, 7 underwent revision surgery. Older age and female sex were associated with lower SAS scores at 15 years, whereas female sex was associated with lower PROMIS-UE scores. There were no factors predictive of ASES or SANE scores. CONCLUSION: At long-term follow-up (≥15 years), the patient-reported outcomes of all-arthroscopic rotator cuff repair show significant improvement from baseline preoperative function and remain durable over a period of 15 years. This information is useful in counseling patients regarding the long-term results of this procedure.

Backside polyethylene wear in reverse shoulder arthroplasty.

BACKGROUND: Aseptic loosening from implant-associated osteolysis in reverse shoulder arthroplasty (RSA) may contribute to premature implant failure. Although articular side polyethylene (PE) damage has been well documented in the literature, no studies to date have investigated backside wear in RSA. The aims of this investigation were to (1) document and compare the damage between the backside and articular surface in explanted RSA components, (2) assess whether certain quadrants have a greater propensity for damage, and (3) report the most common mode(s) of backside PE damage. METHODS: Twenty-one RSA humeral liners retrieved during revision procedures between 2005 and 2014 were included for analysis. The mean time between implantation and extraction was 16 months (10 days-88 months). Diagnoses at the time of revision included dislocation (10), infection (4), mechanical failure (3), loosening (2), and unknown (2). Liners were examined under light microscopy (×10-30 magnification) and damage on the articular and backside of the liner surface was graded using the modified Hood score. The location and damage modality were compared between the articular side and backside of the implant. RESULTS: Damage was noted on the articular surfaces of all 21 liners and on the backside surface of 20 liners. The total damage in all the quadrants was higher on the articular surface than on the backside of the component, with a mean difference in total quadrant damage scores of 11.74 ± 3.53 (P < .001). There was no difference in damage among the quadrants on the backside (P = .44) or the articular surface (P = .08). The articular side exhibited greater scratching, abrasion, and surface deformation than the backside (P < .001). CONCLUSIONS: This short-term retrieval study demonstrated that backside PE damage occurs on the humeral component of RSA implants. There was greater damage to the articular side of the liner but wear to the backside was present in almost all liners. The clinical importance of backside wear in RSA and its overall contribution to PE particulate disease and osteolysis needs further investigation.

A Comprehensive Enhanced Recovery Pathway for Rotator Cuff Surgery Reduces Pain, Opioid Use, and Side Effects.

BACKGROUND: Patients often have moderate to severe pain after rotator cuff surgery, despite receiving analgesics and nerve blocks. There are many suggested ways to improve pain after rotator cuff surgery, but the effects of adopting a pathway that includes formal patient education, a long-acting nerve block, and extensive multimodal analgesia are unclear. QUESTIONS/PURPOSES: (1) Does adoption of a clinical pathway incorporating patient education, a long-acting nerve block, and preemptive multimodal analgesia reduce the worst pain during the first 48 hours after surgery compared with current standard institutional practices? (2) Does adoption of the pathway reduce opioid use? (3) Does adoption of the pathway reduce side effects and improve patient-oriented outcomes? METHODS: From September 2018 to January 2020, 281 patients scheduled for arthroscopic ambulatory rotator cuff surgery were identified for this paired sequential prospective cohort study. Among patients in the control group, 177 were identified, 33% (58) were not eligible, for 11% (20) staff was not available, 56% (99) were approached, 16% (29) declined, 40% (70) enrolled, and 40% (70) were analyzed (2% [4] lost to follow-up for secondary outcomes after postoperative day 2). For patients in the pathway cohort, 104 were identified, 17% (18) were not eligible, for 11% (11) staff was not available, 72% (75) were approached, 5% (5) declined, 67% (70) enrolled, and 67% (70) were analyzed (3% [3] lost to follow-up for secondary outcomes after postoperative day 2). No patients were lost to follow-up for primary outcome; for secondary outcomes, four were lost in the control group and three in the pathway group after postoperative day 2 (p = 0.70). The initial 70 patients enrolled received routine care (control group), and in a subsequent cohort, 70 patients received care guided by a pathway (pathway group). Of the 205 eligible patients, 68% (140) were included in the analysis. This was not a study comparing two tightly defined protocols but rather a study to determine whether adoption of a pathway would alter patient outcomes. For this reason, we used a pragmatic (real-world) study design that did not specify how control patients would be treated, and it did not require that all pathway patients receive all components of the pathway. We developed the pathway in coordination with a group of surgeons and anesthesiologists who agreed to apply the pathway as much as was viewed practical for each individual patient. Patients in both groups received a brachial plexus nerve block with sedation. Major differences between the pathway and control groups were: detailed patient education regarding reasonable pain expectations with a goal of reducing opioid use (no formal educational presentation was given to the control), a long-acting nerve block using bupivacaine with dexamethasone (control patients often received shorter-acting local anesthetic without perineural dexamethasone), and preemptive multimodal analgesia including intraoperative ketamine, postoperative acetaminophen, NSAIDs, and gabapentin at bedtime, with opioids as needed (control patients received postoperative opioids but most did not get postoperative NSAIDS and no controls received gabapentin or separate prescriptions for acetaminophen). The primary outcome was the numerical rating scale (NRS) worst pain with movement 0 to 48 hours after block placement. The NRS pain score ranges from 0 (no pain) to 10 (worst pain possible). The minimum clinically important difference (MCID) [12] for NRS that was used for calculation of the study sample size was 1.3 [18], although some authors suggest 1 [13] or 2 [5] are appropriate; if we had used an MCID of 2, the sample size would have been smaller. Secondary outcomes included NRS pain scores at rest, daily opioid use (postoperative day 1, 2, 7, 14), block duration, patient-oriented pain questions (postoperative day 1, 2, 7, 14), and patient and physician adherence to pathway. RESULTS: On postoperative day 1, pathway patients had lower worst pain with movement (3.3 ± 3.1) compared with control patients (5.6 ± 3.0, mean difference -2.7 [95% CI -3.7 to -1.7]; p < 0.001); lower scores were also seen for pain at rest (1.9 ± 2.3 versus 4.0 ± 2.9, mean difference -2.0 [95% CI -2.8 to -1.3]; p < 0.001). Cumulative postoperative opioid use (0-48 hours) was reduced (pathway oral morphine equivalent use was 23 ± 28 mg versus 44 ± 35 mg, mean difference 21 [95% CI 10 to 32]; p < 0.01). The greatest difference in opioid use was in the first 24 hours after surgery (pathway 7 ± 12 mg versus control 21 ± 21 mg, mean difference -14 [95% CI -19 to -10]; p < 0.01). On postoperative day 1, pathway patients had less interference with staying asleep compared with control patients (0.5 ± 1.6 versus 2.6 ± 3.3, mean difference -2.2 [95% CI -3.3 to -1.1]; p < 0.001); lower scores were also seen for interference with activities (0.9 ± 2.3 versus 1.9 ± 2.9, mean difference -1.1 [95% CI -2 to -0.1]; p = 0.03). Satisfaction with pain treatment on postoperative day 1 was higher among pathway patients compared with control patients (9.2 ± 1.7 versus 8.2 ± 2.5, mean difference 1.0 [95% CI 0.3 to 1.8]; p < 0.001). On postoperative day 2, pathway patients had lower nausea scores compared with control patients (0.3 ± 1.1 versus 1 ± 2.1, mean difference -0.7 [95% CI -1.2 to -0.1]; p = 0.02); lower scores were also seen for drowsiness on postoperative day 1 (1.7 ± 2.7 versus 2.6 ± 2.6, mean difference -0.9 [95% CI - 1.7 to -0.1]; p = 0.03). CONCLUSION: Adoption of the pathway was associated with improvement in the primary outcome (pain with movement) that exceeded the MCID. Patients in the pathway group had improved patient-oriented outcomes and fewer side effects. This pathway uses multiple analgesic drugs, which may pose risks to elderly patients, in particular. Therefore, in evaluating whether to use this pathway, clinicians should weigh the effect sizes against the potential risks that may emerge with large scale use, consider the difficulties involved in adapting a pathway to local practice so that pathway will persist, and recognize that this study only enrolled patients among surgeons and the anesthesiologists that advocated for the pathway; results may have been different with less enthusiastic clinicians. This pathway, based on a long-lasting nerve block, multimodal analgesia, and patient education can be considered for adoption. LEVEL OF EVIDENCE: Level II, therapeutic study.

Arthroscopic-Assisted Coracoclavicular Ligament Reconstruction: Clinical Outcomes and Return to Activity at Mean 6-Year Follow-Up.

PURPOSE: To report clinical and functional outcomes including return to preinjury activity level following arthroscopic-assisted coracoclavicular (CC) ligament reconstruction (AA-CCR) and to determine associations between return to preinjury activity level, radiographic outcomes, and patient-reported outcomes following AA-CCR. METHODS: A institutional registry review of all AA-CCR using free tendon grafts from 2007 to 2016 was performed. Clinical assessment included Single Assessment Numeric Evaluation (SANE) score and return to preinjury activity level at final follow-up. Treatment failure was defined as (1) revision acromioclavicular stabilization surgery, (2) unable to return to preinjury activity level, or (3) radiographic loss of reduction (RLOR, >25% CC distance compared with contralateral side). SANE scores, return to activity, and RLOR were compared between patients within each category of treatment failure, by grade of injury, and whether concomitant pathology was treated. RESULTS: There were 88 patients (89.8% male) with mean age of 39.6 years and minimum 2-year clinical follow-up (mean 6.1 years). Most injuries were Rockwood grade V (63.6%). Mean postoperative SANE score was 86.3 ± 17.5. Treatment failure occurred in 17.1%: 8.0% were unable to return to activity, 5.7% had RLOR, and 3.4% underwent revision surgery due to traumatic reinjury. SANE score was lower among patients who were unable to return to activity compared with those with RLOR and compared with nonfailures (P = .0002). There were no differences in revision surgery rates, return to activity, or SANE scores according to Rockwood grade or if concomitant pathology was treated. CONCLUSIONS: AA-CCR with free tendon grafts resulted in good clinical outcomes and a high rate of return to preinjury activity level. RLOR did not correlate with return to preinjury activity level. Concomitant pathology that required treatment did not adversely affect outcomes. Return to preinjury activity level may be a more clinically relevant outcome measure than radiographic maintenance of acromioclavicular joint reduction. LEVEL OF EVIDENCE: IV (Case Series).

Surgical Treatment of Iatrogenic Nerve Injury Following Arthroscopic Capsulolabral Repair.

PURPOSE: Case reports of nerve injuries following arthroscopic capsulolabral repair emphasize the proximity of major nerves to the glenoid. This study describes preoperative localization using nerve-sensitive magnetic resonance imaging in a small cohort of patients with iatrogenic nerve injuries following arthroscopic capsulolabral repair and the outcomes of nerve repair in these patients. METHODS: Cases of iatrogenic nerve injury following arthroscopic capsulolabral repair referred to 2 surgeons from January 2017 to December 2019 were identified. Clinical charts, electrodiagnostic testing, magnetic resonance imaging studies, and operative reports were reviewed. RESULTS: Four cases of iatrogenic nerve injury were identified. The time to presentation to our institution ranged from 2 weeks to 8 years. The axillary nerves in 3 cases were tethered by a suture at the inferior glenoid, whereas 1 case had a suture tied around the radial and median nerves inferior to the glenohumeral joint capsule. One case underwent excision and nerve transfer, 1 underwent excision and nerve repair, and 2 underwent suture removal and neurolysis. Open and arthroscopic approaches, including a recently described approach to the axillary nerve in the "blind zone," were used. Three cases demonstrated good recovery of all affected motor and sensory functions after surgery. At the 10-month follow-up, 1 case had persistent weakness, but there was evidence of axonal regeneration on electrodiagnostic testing. CONCLUSIONS: Arthroscopic capsulolabral repair places regional nerves, particularly the axillary nerve, at risk owing to their proximity to the joint capsule and inferior glenoid. Patients with neuropathic pain in the distribution of affected nerves with corresponding sensorimotor loss following arthroscopic capsulolabral surgery should undergo focused magnetic resonance imaging with nerve-sensitive sequences and electrodiagnostic testing to localize the injury. The use of multiple surgical windows to the axillary nerve in the "blind zone" enables full visualization for neurolysis, suture removal, and nerve repair or transfer. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.