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Background: Surgical and nonoperative management of anterior cruciate ligament (ACL) injuries seek to mitigate the risk of knee instability and secondary meniscal injury. However, the associated risk and timing of secondary meniscal tears have not been completely elucidated. Purpose: To compare risk and timing of secondary meniscal injury between patients receiving nonoperative management, delayed ACL reconstruction (ACLR), and early ACLR using a machine learning survival analysis. Study Design: Cohort study; Level of evidence, 3. Methods: A geographic database was used to identify and review records of patients with a diagnosis of ACL rupture between 1990 and 2016 with minimum 2-year follow-up. Patients undergoing ACLR were matched 1:1 with nonoperatively treated controls. Rate and time to secondary meniscal tear were compared using random survival forest algorithms; independent models were developed and internally validated for predicting injury-free duration in both cohorts. Performance was measured using out-of-bag c-statistic, calibration, and Brier score. Model interpretability was enhanced using global variable importance and partial dependence curves. Results: The study included 1369 patients who underwent ACLR and 294 patients who had nonoperative treatment. After matching, no significant differences in rates of secondary meniscal tear were found ( P = .09); subgroup analysis revealed the shortest periods of meniscal survival in patients undergoing delayed ACLR. The random survival forest algorithm achieved excellent predictive performance for the ACLR cohort, with an out-of-bag c-statistic of 0.80 and a Brier score of 0.11. Significant variables for risk of meniscal tear for the ACLR cohort included time to return to sports or activity ≤350 days, time to surgery ≥50 days, age at injury ≤40 years, and high-impact or rotational landing sports, whereas those in the nonoperative cohort model included time to RTS ≤200 days, visual analog scale pain score >3 at consultation, hypermobility, and noncontact sports. Conclusion: Delayed ACLR demonstrated the greatest long-term risk of meniscal injury compared with nonoperative treatment or early ACLR. Risk factors for decreased meniscal survival after ACLR included increased time to surgery, shorter time to return to sports or activity, older age at injury, and involvement in high-impact or rotational landing sports. Pending careful external validation, these models may be deployed in the clinical space to provide real-time insights and enhance decision making.

Purpose To investigate the incidence of anteroinferior glenoid rim fractures (AGRFs) after anterior shoulder instability (ASI) in patients aged 50 years or older, identify risk factors for surgical intervention for AGRFs, compare initial treatment strategies, and compare clinical outcomes of patients with and without associated AGRFs. Methods An established geographic medical record system was used to identify patients aged 50 years or older with ASI between 1994 and 2016. Patients with radiographic evidence of AGRFs were identified and matched 1:1 to patients without AGRFs. Outcome measures included recurrent instability, recurrent pain events, conversion to arthroplasty, and osteoarthritis graded with the Samilson‐Prieto classification for post‐instability arthritis. Results Overall, 177 patients were identified, with a mean follow‐up period of 10.8 years. Of these patients, 41 (23.2%) had AGRFs and were matched to 41 control patients without AGRFs. The average age was 58.6 and 58.2 years for the AGRF and control groups, respectively. Rates of surgical intervention (27% vs 49%), recurrent instability (12% vs 20%), progression of osteoarthritis (34% vs 39%), and conversion to arthroplasty (2% vs 5%) were similar between AGRF patients and controls. For patients with AGRFs, increased bone fragment size (odds ratio, 1.1) and increased body mass index (odds ratio, 1.2) correlated with an increased risk of surgery. The cutoff value for an increased risk of surgery in patients with AGRFs was a fragment size 33% of the glenoid width or greater. Conclusions Of patients aged 50 years or older at presentation of ASI, 23.2% presented with an associated AGRF. A fragment size 33% of the glenoid width or greater and a higher patient body mass index were significant factors for surgical intervention; however, most patients did not require surgery and still showed acceptable clinical outcomes, and the most common reason for surgical intervention was a rotator cuff tear. Overall, the presence of an AGRF did not portend a worse prognosis as treatment strategies and long‐term outcomes including recurrent instability, progression of osteoarthritis, and conversion to arthroplasty were similar to those in patients without AGRFs. Level of Evidence Level III, retrospective comparative study.

AbstractPurposeThis study sought to develop and internally validate a machine learning model to identify risk factors and quantify overall risk of secondary meniscus injury in a longitudinal cohort after primary ACL reconstruction (ACLR).MethodsPatients with new ACL injury between 1990 and 2016 with minimum 2‐year follow‐up were identified. Records were extensively reviewed to extract demographic, treatment, and diagnosis of new meniscus injury following ACLR. Four candidate machine learning algorithms were evaluated to predict secondary meniscus tears. Performance was assessed through discrimination using area under the receiver operating characteristics curve (AUROC), calibration, and decision curve analysis; interpretability was enhanced utilizing global variable importance plots and partial dependence curves.ResultsA total of 1187 patients underwent ACLR; 139 (11.7%) experienced a secondary meniscus tear at a mean time of 65 months post‐op. The best performing model for predicting secondary meniscus tear was the random forest (AUROC = 0.790, 95% CI: 0.785–0.795; calibration intercept = 0.006, 95% CI: 0.005–0.007, calibration slope = 0.961 95% CI: 0.956–0.965, Brier’s score = 0.10 95% CI: 0.09–0.12), and all four machine learning algorithms outperformed traditional logistic regression. The following risk factors were identified: shorter time to return to sport (RTS), lower VAS at injury, increased time from injury to surgery, older age at injury, and proximal ACL tear.ConclusionMachine learning models outperformed traditional prediction models and identified multiple risk factors for secondary meniscus tears after ACLR. Following careful external validation, these models can be deployed to provide real‐time quantifiable risk for counseling and timely intervention to help guide patient expectations and possibly improve clinical outcomes.Level of evidenceIII.

Background: Diagnosis and treatment of posterior shoulder instability (PSI) has improved with advances in imaging and surgical technique. However, the relationship between PSI and osteoarthritis (OA) remains unclear. Purpose: To evaluate a population-based cohort to (1) determine the rate of symptomatic OA, (2) identify patient characteristic risk factors for OA, and (3) evaluate the effect of posterior capsulolabral repair on OA progression. Study Design: Case-control study; Level of evidence, 3. Methods: After review of 324 patient records, we included 115 patients (14 female, 101 male) diagnosed with PSI between January 1994 and July 2012 with an average follow-up of 12.5 years (range, 5-23 years). Medical records were reviewed for patient characteristics, injury characteristics, surgical details (if any), and radiographic progression of OA. Kaplan-Meier survival was used to estimate survival free of OA; characteristics associated with OA progression were determined via univariate Cox regression models, and associated 95% CIs and hazard ratios (HRs) are presented. Results: Overall, 14% (16/115) of patients had radiographic progression of symptomatic glenohumeral arthritis, with 5-year survival of 88.3% (95% CI, 79.7%-97.3%). Older age at the time of instability diagnosis was associated with arthritis progression (10-year unit HR, 1.95; 95% CI, 1.26-3.03). Patients who underwent surgery demonstrated increased radiographic progression of OA (HR, 4.03; 95% CI, 1.23-13.23). There was a trend of increased OA in patients treated with labral debridement compared with repair despite lower baseline levels of OA; however, this difference was not statistically significant ( P = .09). Conclusion: Symptomatic glenohumeral arthritis is not seen routinely in patients with PSI. Although uncommon, an age of at least 30 years at the time of diagnosis and surgical intervention were identified as risk factors for developing symptomatic arthritis at long-term follow-up.

Objectives:Introduction: Wrestling is a physically demanding sport with young athletes prone to anterior cruciate ligament (ACL) injuries. However, there is a paucity of data evaluating the results of ACL reconstruction (ACLR) in this cohort. Purpose: To assess patient-reported outcomes, reoperation rates, graft survival, and return to play (RTP) following ACLR in a large cohort of competitive wrestlers Methods: All competitive wrestlers (high school, collegiate, or professional) with a history of an ACLR at a single institution between 2000 and 2019 were retrospectively identified. Graft failure was defined as a re-tear determined by clinical or advanced imaging evaluation, and/or revision ACL reconstruction. All patients were contacted for determination of reinjury rates, current sport status, visual analog scale (VAS), International Knee Documentation Committee (IKDC) and Tegner activity scores. Results: 118 knees in 114 wrestlers were included at a median follow-up time of 5.8 years (IQR: 3.6 – 10.3). The median age was 17 years (15 – 18) with 116 (98%) males. ACLR was most often performed with bone-patellar tendon-bone (BTB) autograft (n = 64; 54%) or hamstring tendon (HT) autograft (n = 43; 36%). At final follow-up, 80% of athletes were able to RTP at a median of 273 days (IQR: 203 – 379). Graft failure occurred in 17 (14%) patients at a median time of 1.4 years (IQR: 0.8 – 4.7) after the index ACLR. BTB autograft demonstrated a lower failure rate compared to HT autograft (8% vs. 21%; P = 0.044). Kaplan-Meier survivorship free from graft failure for the entire cohort was 95.3% at 1 year, 92.5% at 2 years, 89.8% at 5 years, 84.6 at 10 years, 77.6 at 20 years. BTB autograft was associated with better survival than HT autograft up to 15 years after the index ACLR (90.4% vs. 76.3%; P = 0.030). Conclusions: Return to competitive wrestling was observed in 80% of athletes after ACLR, with 14% of wrestlers experiencing graft failure. BTB autograft reconstruction may serve as a more durable graft for competitive wrestlers with lower rates of failure when compared to HT autograft even up to 15 years after surgery. [Table: see text][Figure: see text][Figure: see text][Figure: see text]

Objectives: Distal biceps tendon tears, although rare, significantly impair patient’s elbow mobility and function. There is a paucity of contemporary literature reporting long term outcomes of distal biceps (DB) injuries. Therefore, the authors sought to identify magnetic resonance imaging (MRI) confirmed distal bicep tears and report on (1) patient demographics and injury characteristics of all patients with distal bicep pathology, (2) outcomes of all patients with non-operatively managed DB pathology, and (3) outcomes of all patients with operatively managed DB pathology. Methods: Patients with an MRI-confirmed distal biceps rupture from 1996 to 2016 were identified through an institutional image database. Patients from the initial search were then cross-referenced with the [REDACTED] 1 to ensure record availability. Patients were included if they had complete medical records and ≥5 years of clinical follow-up. Patients with inflammatory arthritis and enthesitis, polytrauma, or incidental findings without clinical assessment were excluded. Medical records were reviewed to confirm the diagnosis of distal biceps tears and obtain further subject details. Results: A total of 158 patients (22 female, 136 male) with a mean age 51.5 years (44.8-61.2) were identified and included. Baseline patient demographics including BMI, smoking status, dominant-handedness, laborer occupation, and gender were gathered (Table 1). Patients had a mean clinical follow-up of almost 14 years (Table 1, range 8.4 -17.8). Outcomes of the 52 non-operative and 106 operatively managed patients, included severe complications, functional outcomes, and health-related productivity loss are reported in Table 2. There were 7 re-operations (4%), 5 re-ruptures (3%), and overall 35% of the operatively treated cohort experienced a complication. Conclusions: Patients with distal bicep pathology tended to be a male laborer in their 50s without clinically significantly associated risk factors. The majority of patients regained full ROM, and 83% were able to return to work without modifications, irregardless of operative or non-operative management. At long term follow up, patients treated operatively were more likely to report missing time from work and averaged more days missed than their non-operatively treated counterparts. Additionally, operative patients had no statistically significant gains functional outcomes, and were subject to potential post-operative complications. Surgeon bias may play a role in deciding treatment for distal biceps tears. As such, careful patient selection for surgical intervention for distal biceps pathology should be employed; surgeons should consider restricting surgical intervention to patients who have significant clinical symptoms or fail non-operative management. [Table: see text][Table: see text]

Objectives: Background: Although they are common, there remains a paucity of data regarding traumatic anterior shoulder dislocations (ASI) associated with anteroinferior glenoid rim fractures (AGRF) in older patients. Purpose: To describe the incidence of AGRF in this population following ASI, identify risk factors for AGRF, compare treatment strategies, and compare clinical outcomes of patients with and without an associated AGRF. Methods: An established geographic medical record system was used to identify patients >50 years of age with ASI between 1994 and 2016. Patients with radiographic evidence of AGRF were identified and matched 1:1 to patients without AGRF. Comparative analysis was conducted to determine differences between groups. Results: Overall, 186 patients were identified with a mean follow-up of 10.4 years (range, 2.0 – 25.4). Of these, 42 (22.6%) had AGRF and were matched to 42 control patients without AGRF. Average age was 58.9 and 58.2 years for the AGRF and control groups, respectively. Rates of surgical intervention (29% vs. 43%), recurrent instability (14% vs. 17%), progression of osteoarthritis (34% vs. 39%), and conversion to arthroplasty (2% vs. 5%) were similar between AGRF and control cohorts. Control patients were more likely to report recurrent pain (p=.046). For patients with AGRF, increased bone fragment size (OR 1.1) and increased BMI (OR 1.2) correlated with an increased risk for surgery. The cut-off value for surgery in patients with AGRF was a fragment size ≥33% of the glenoid width. Conclusions: In patients ≥ 50 years at presentation of ASI, 22.6% presented with an associated AGRF. Increased fragment size and greater patient BMI were significant factors associated with undergoing surgical intervention; however, most patients did not require surgery. Patients without AGRF were more likely to report recurrent pain, possibly due to a higher prevalence of rotator cuff derangement. Overall, the presence of an AGRF did not portend a worse prognosis as treatment strategies and long-term outcomes in terms of recurrent instability, progression of osteoarthritis, and conversion to arthroplasty were similar between patients with and without AGRF at the time of ASI diagnosis.

Objectives: Anterior shoulder instability (ASI) is a well-studied topic in young patients, however there is a dearth of knowledge about older patients with this pathology. The goals of this study were to describe patient demographics, injury characteristics and outcomes in patients >50 years old with anterior shoulder instability along with historical trends in diagnosis and treatment. Methods: An established geographic database was used to identify 179 patients who experienced new onset anterior shoulder instability after the age 50 between 1994-2016. Mean age was 59.7 years, mean BMI was 31.3 and 54.2% were female. The dominant arm was involved in 62.2% of instability events. 26.8% of our study population were laborers and 50% reported current or former smoking habits. The primary etiology for ASI involved trauma in 96.6% of cases. Comparative analysis was performed to identify differences between age groups. Mean follow up time was 11 years. Results: The overall incidence of ASI in our study population was 28.8/100,000 person years with the highest incidence in the age cohort 60-64 at 38.9/100,000 person years. At initial presentation, 73% of all patients were found to have a lesion apparent on either XR or MRI. Rotator cuff tears were found in 92.4% of all patients undergoing MRIs. 26.2% ultimately progressed to surgery at a mean time of 1.57 years after injury. 53% of all surgical procedures involved a rotator cuff repair whereas only 25% were performed for instability. In terms of historical trends, the one-year rate of obtaining an MRI after an ASI event has increased from 10% in the late 1990s to 46% in 2015-16. Similarly, the one-year rate of performing surgery has increased from 5.1% to 47% from 1994-1999 to 2015-2016. Conclusions: In our cohort, patients over the age of 50 with ASI were found to often have concomitant pathology on imaging, however only ¼ of all patients required surgery. Although the rate of ASI has stayed relatively stable over the last 20 years, the rate of obtaining an MRI and of surgical management has increased. [Figure: see text]

Objectives: Distal biceps tendon tears, although rare, significantly impair patient’s elbow mobility and function. There is a paucity of literature reporting outcomes of partial thickness tears to inform management strategies. Therefore, the authors sought to identify magnetic resonance imaging (MRI) confirmed partial thickness distal biceps tears and report on (1) demographics and treatment strategies, (2) outcomes and complications, and (3) any identifiable risk factors for progression to surgery or full thickness tear. Methods: Patients who experienced a partial thickness distal biceps tear confirmed on MRI from 1996 to 2016 were identified by a musculoskeletal radiologist through an institutional image database. Patients were included if they had complete medical records and at least one visit of clinical follow-up. Patients with inflammatory arthritis and enthesitis, polytrauma, or incidental findings without clinical assessment were excluded. Medical records were reviewed to confirm the diagnosis and obtain study details. Multivariate logistic regression models were created using baseline characteristics, injury details and physical exam findings in order to predict operative intervention. Results: Overall, 111 patients (22F, 89M, age: 53.6 years ± 13) were identified and included. Baseline injury characteristics and patient demographics including weakness in elbow flexion, forearm supination, and patient reported sensation at time of injury were all found to be statistically different between treatment groups (Table 1). Patients were followed to a mean of 10 years of clinical follow up. Within the cohort, 57 patients were treated non-operatively, while 54 were treated operatively. Patients who received surgical intervention were more likely to report missing time from work and greater loss of productivity due to missed time (Table 2); however, almost 90% of patients returned to work without restrictions, regardless of treatment modality (88% vs 88%, Table 2). For surgical patients, there were 5 re-operations (9%), 3 re-ruptures (6%), and overall, 31% of the operatively treated cohort experienced a complication. Results of the final multivariate logistic regression model are included in Table 3; final model variables included age at initial consult, tenderness to palpation tendon insertion on exam, and supination weakness. Of these, supination weakness at initial consult was found to be a statistically significant predictor for surgical intervention (p=.001, OR=24.8). Conclusions: Operative patients tended to be male with more profound supination weakness; these patients tended to report increased loss of productivity due to time missed after treatment. At 10 year clinical follow up 31% experienced some complication and 9% underwent a re-operation. However, patients demonstrated uniform ability to return to work without modification and no statistical differences in functional outcomes, regardless of treatment modality. Patients who suffer from a partial distal biceps tear should be counseled that operative management represents a balance of returning function with potential complications and increased loss of productivity. [Table: see text][Table: see text][Table: see text]

Objectives: The medial patellofemoral ligament (MPFL) is the primary soft tissue restraint to lateral patellar translation and is often disrupted with a lateral patellar dislocation. Surgical management for recurrent patellar instability focuses on restoring MPFL function with repair or reconstruction techniques. Recent studies have favored reconstruction over repair, but no long-term, comparative studies are available in the literature. Methods: A total of 55 patients (58 knees) with recurrent lateral instability were treated between 2005 and 2012 with either MPFL repair or MPFL reconstruction. Exclusion criteria included prior or concomitant tibial tubercle osteotomy or trochleoplasty, and follow-up less than 8 years. Pre- and post-operative demographic, surgical, imaging and clinical data were recorded for each patient. Results: MPFL repair was performed on 26 patients (29 knees; 14 females, 15 males) at a mean age of 19.1 years. MPFL reconstruction was performed on 29 patients (29 knees; 18 females, 11 males) at a mean age of 18.2 years. Mean follow-up was 12.0 years (range 8.3-18.9). The reconstruction group had a significantly lower rate of recurrent dislocation compared to the repair group (14% vs 41%, p=0.019) at final follow up. There were no differences in the number of pre-operative dislocations (greater than or less than 3), degree of patellar facet chondromalacia, TT-TG distance, or Tegner scores. The reconstruction group had significantly more time from injury to surgery compared to the repair group (median, 1,460 days vs 627 days, p =0.007). There were no differences in post-operative Tegner, Lysholm or Kujala scores at final follow-up. Additionally, there were no differences in return to play rates (repair 80.8% vs reconstruction 75.0%, p=0.610) or reoperation rates (repair 20.7% vs reconstruction 13.8%, p=0.487). Conclusions: Repair of the MPFL leads to nearly 3-fold higher rate of recurrent patellar dislocation (41% vs. 14%) at long term follow-up compared to MPFL reconstruction. However, MPFL repair and reconstruction provide similar clinical results, return to play rates and reoperation rates. [Table: see text][Table: see text]