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Context: Ball velocity for baseball pitchers is influenced by a multitude of factors along the kinetic chain. While a vast amount of data currently exist exploring lower-extremity kinematic and strength factors in baseball pitchers, no previous study has systematically reviewed the available literature. Objective: The aim of this systematic review was to perform a comprehensive assessment of the available literature investigating the association between lower-extremity kinematic and strength parameters and pitch velocity in adult pitchers. Evidence Acquisition: Cross-sectional studies that investigated the association between lower-body kinematic and strength factors and ball velocity in adult pitchers were selected. A methodological index for nonrandomized studies checklist was used to evaluate the quality of all included studies. Evidence Synthesis: Seventeen studies met the inclusion criteria comprising a total of 909 pitchers (65%, professional, 33% college, and 3% recreational). The most studied elements were hip strength and stride length. The mean methodological index for nonrandomized studies score was 11.75 of 16 (range = 10–14). Pitch velocity was found to be influenced by several lower-body kinematic and strength factors including the following: (1) hip range of motion and strength of muscles around the hip and pelvis, (2) alterations in stride length, (3) alterations in lead knee flexion/extension, and (4) several pelvic and trunk spatial relationships throughout the throwing phase. Conclusions: Based on this review, we conclude that hip strength is a well-established predictor of increased pitch velocity in adult pitchers. Further studies in adult pitchers are needed to elucidate the effect of stride length on pitch velocity given mixed results across multiple studies. This study can provide a basis for trainers and coaches to consider the importance of lower-extremity muscle strengthening as a means by which adult pitchers can improve pitching performance.

The purpose of this study was to identify surgical complications after distal humerus fracture fixation as well as correlations between these complications and patient variables. A total of 132 patients underwent open reduction and internal fixation of traumatic distal humerus fractures between October 2011 and June 2018. Included were adult patients who underwent surgical fixation and had more than 6 months of follow-up. Excluded were patients with inadequate radiographic imaging, less than 6 months of follow-up, and previous distal humerus surgery. Multivariate logistic regression models controlling for age and body mass index were used to determine preoperative factors predictive of postoperative complications. A total of 73 patients were included in this analysis. Surgical complications were reported for 17 patients. Reoperation was required for 13 patients. Open injury at presentation was predictive of delayed union. Predictors of subsequent elbow surgery included younger age, polytrauma, open fracture, and ulnar nerve injury at the time of injury. Radial nerve injury at the time of presentation was also a risk factor for postoperative radial nerve symptoms. Predictors of postoperative heterotopic ossification included older age. Thirty-one patients had an olecranon osteotomy during their open reduction and internal fixation and none went on to nonunion. There were 13 patients with ulnar nerve complications. Of these patients, 3 had undergone an ulnar nerve transposition. None of the other studied variables were predictors of complications, malunion, or nonunion at latest follow-up. Although open reduction and internal fixation is effective in treating distal humerus fractures, its complications cannot be overlooked. Open fractures are more likely to go on to delayed union. Ulnar nerve injury, open fracture, and polytrauma were predictive for reoperation. Older patients were less likely to have subsequent surgery but more likely to develop heterotopic ossification. By identifying at-risk patients, managing physicians can better prognosticate and counsel patients on their recovery. [ Orthopedics . 202x;4x(x):xx–xx.]

Background: Bone bruises are commonly seen on magnetic resonance imaging (MRI) in acute anterior cruciate ligament (ACL) injuries and can provide insight into the underlying mechanism of injury. There are limited reports that have compared the bone bruise patterns between contact and noncontact mechanisms of ACL injury. Purpose: To examine and compare the number and location of bone bruises in contact and noncontact ACL injuries. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Three hundred twenty patients who underwent ACL reconstruction surgery between 2015 and 2021 were identified. Inclusion criteria were clear documentation of the mechanism of injury and MRI within 30 days of the injury on a 3-T scanner. Patients with concomitant fractures, injuries to the posterolateral corner or posterior cruciate ligament, and/or previous ipsilateral knee injury were excluded. Patients were stratified into 2 cohorts based on a contact or noncontact mechanism. Preoperative MRI scans were retrospectively reviewed by 2 musculoskeletal radiologists for bone bruises. The number and location of the bone bruises were recorded in the coronal and sagittal planes using fat-suppressed T2-weighted images and a standardized mapping technique. Lateral and medial meniscal tears were recorded from the operative notes, while medial collateral ligament (MCL) injuries were graded on MRI. Results: A total of 220 patients were included, with 142 (64.5%) noncontact injuries and 78 (35.5%) contact injuries. There was a significantly higher frequency of men in the contact cohort compared with the noncontact cohort (69.2% vs 54.2%, P = .030), while age and body mass index were comparable between the 2 cohorts. The bivariate analysis demonstrated a significantly higher rate of combined lateral tibiofemoral (lateral femoral condyle [LFC] + lateral tibial plateau [LTP]) bone bruises (82.1% vs 48.6%, P < .001) and a lower rate of combined medial tibiofemoral (medial femoral condyle [MFC] + medial tibial plateau [MTP]) bone bruises (39.7% vs 66.2%, P < .001) in knees with contact injuries. Similarly, noncontact injuries had a significantly higher rate of centrally located MFC bone bruises (80.3% vs 61.5%, P = .003) and posteriorly located MTP bruises (66.2% vs 52.6%, P = .047). When controlling for age and sex, the multivariate logistical regression model demonstrated that knees with contact injuries were more likely to have LTP bone bruises (OR, 4.721 [95% CI, 1.147-19.433], P = .032) and less likely to have combined medial tibiofemoral (MFC + MTP) bone bruises (OR, 0.331 [95% CI, 0.144-0.762], P = .009) compared with those with noncontact injuries. Conclusion: Significantly different bone bruise patterns were observed on MRI based on ACL injury mechanism, with contact and noncontact injuries demonstrating characteristic findings in the lateral tibiofemoral and medial tibiofemoral compartments, respectively.

To determine the incidence of ramp lesions and posteromedial tibial plateau (PMTP) bone bruising on magnetic resonance imaging (MRI) in patients with multiligament knee injuries (MLKIs) and an intact anterior cruciate ligament (ACL).A retrospective review of consecutive patients surgically treated for MLKIs at 2 level I trauma centers between January 2001 and March 2021 was performed. Only MLKIs with an intact ACL that received MRI scans within 90 days of the injury were included. All MLKIs were diagnosed on MRI and confirmed with operative reports. Two musculoskeletal radiologists retrospectively rereviewed preoperative MRIs for evidence of medial meniscus ramp lesions (MMRLs) and PMTP bone bruises using previously established classification systems. Intraclass correlation coefficients were used to calculate the reliability between the radiologists. The incidence of MMRLs and PMTP bone bruises was quantified using descriptive statistics.A total of 221 MLKIs were identified, of which 32 (14.5%) had an intact ACL (87.5% male; mean age of 29.9 ± 8.6 years) and were included. The most common MLKI pattern was combined injury to the posterior cruciate ligament and posterolateral corner (n = 27, 84.4%). PMTP bone bruises were observed in 12 of 32 (37.5%) patients. Similarly, MMRLs were diagnosed in 12 of 32 (37.5%) patients. A total of 8 of 12 (66.7%) patients with MMRLs demonstrated evidence PMTP bone bruising.Over one-third of MLKI patients with an intact ACL were diagnosed with MMRLs on MRI in this series. PMTP bone bruising was observed in 66.7% of patients with MMRLs, suggesting that increased vigilance for identifying MMRLs at the time of ligament reconstruction should be practiced in patients with this bone bruising pattern.Level IV, retrospective case series.

To compare complication rates and 5-year reoperation rates between open debridement (OD) and arthroscopic debridement (AD) for lateral epicondylitis.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.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).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 III, cross-sectional study.

Background: Individualized risk prediction has become possible with machine learning (ML), which may have important implications in enhancing clinical decision making. We previously developed an ML algorithm to predict propensity for clinically meaningful outcome improvement after hip arthroscopy for femoroacetabular impingement syndrome. External validity of prognostic models is critical to determine generalizability, although it is rarely performed. Purpose: To assess the external validity of an ML algorithm for predicting clinically meaningful improvement after hip arthroscopy. Study Design: Cohort study; Level of evidence, 3. Methods: An independent hip preservation registry at a tertiary academic medical center was queried for consecutive patients/athletes who underwent hip arthroscopy for femoroacetabular impingement syndrome between 2015 and 2017. By assuming a minimal clinically important difference (MCID) outcome/event proportion of 75% based on the original study, a minimum sample of 132 patients was required. In total, 154 patients were included. Age, body mass index, alpha angle on anteroposterior pelvic radiographs, Tönnis grade and angle, and preoperative Hip Outcome Score–Sports Subscale were used as model inputs to predict the MCID for the Hip Outcome Score–Sports Subscale 2 years postoperatively. Performance was assessed using identical metrics to the internal validation study and included discrimination, calibration, Brier score, and decision curve analysis. Results: The concordance statistic in the validation cohort was 0.80 (95% CI, 0.71 to 0.87), suggesting good to excellent discrimination. The calibration slope was 1.16 (95% CI, 0.74 to 1.61) and the calibration intercept 0.13 (95% CI, –0.26 to 0.53). The Brier score was 0.15 (95% CI, 0.12 to 0.18). The null model Brier score was 0.20. Decision curve analysis revealed favorable net treatment benefit for patients with use of the algorithm as compared with interventional changes made for all and no patients. Conclusion: The performance of this algorithm in an independent patient population in the northeast region of the United States demonstrated superior discrimination and comparable calibration to that of the derivation cohort. The external validation of this algorithm suggests that it is a reliable method to predict propensity for clinically meaningful improvement after hip arthroscopy and is an essential step forward toward introducing initial use in clinical practice. Potential uses include integration into electronic medical records for automated prediction, enhanced shared decision making, and more informed allocation of resources to optimize patient outcomes.

Background: Given the increasing interest and potential use of social media for the promotion of orthopedic literature, there is a need to better understand Altmetrics. Purposes: We sought to determine the relationship between the Altmetric Attention Score (AAS) and the number of citations for articles on total joint arthroplasty (TJA) published in orthopedics journals. We also sought to determine the predictors of greater social media attention for these articles. Methods: Articles on TJA published in Bone and Joint Journal (BJJ), Journal of Bone and Joint Surgery (JBJS), Clinical Orthopedics and Related Research (CORR), Journal of Arthroplasty, Journal of Knee Surgery, Hip International, and Acta Orthopaedica in 2016 were extracted ( n = 498). One-way analysis of variance with Bonferroni corrections was used to compare AAS and citations across journals. Multivariate regressions were used to determine predictors of social media attention and number of citations. Results: The mean AAS and number of citations were 7.5 (range: 0–289) and 16.7 (range: 0–156), respectively. Significant between-group effects were observed according to journal for AAS and number of citations. Publishing an article in JBJS was the strongest predictor of higher number of citations. Publishing an article in BJJ was the only independent predictor of higher AAS, while publishing an article in JBJS or CORR trended toward statistical significance. A higher AAS was a significant predictor of a higher number of citations. Number of citations and number of study references were positive predictors of greater social media attention on Twitter and Facebook. Conclusions: In articles on TJA published in 7 journals in 2016, a higher AAS was a associated with a higher number of citations. Various bibliometric characteristics were found to be significantly associated with greater social media attention; the most common influences were number of citations and number of references. Researchers in orthopedics can use this information when considering how to assess the impact of their work.

Background: It is unknown how different pitch count limits and rest day requirements affect cumulative pitch counts during a baseball season. Purpose: To determine (1) the variability of pitch count rules in high school baseball and (2) the theoretical effect of different pitch count limits and rest day combinations on game, weekly, and seasonal pitch totals in high school baseball pitchers. Study Design: Cross-sectional study. Methods: Pitch count rules for the 2019-2020 academic year for 48 sanctioned states were recorded from each state’s athletic association website. Maximum pitch count limits were recorded along with the number of pitches allowed before requiring 0 to 5 rest days before the next pitching outing. Rules were also analyzed for several distinctions, including the athlete’s level of competition, age, and grade. To determine the effect of pitch count rules and rest days, a theoretical 3-month season was calculated in the following scenarios: (1) variable maximum pitch count limits with a universal 3-day rest requirement, (2) universal 110 pitch count limit with variable rest day requirements (3, 4, or 5 days), and (3) actual pitch count limits and required rest days for every state assuming pitchers throw as many pitches as allowed. Analysis of variance and Student t tests were used to compare between-group and intragroup seasonal pitch totals based on variations in required rest days. Results: The most common maximum pitch count limit for a varsity high school athlete was 110 pitches (range, 100-125 pitches) with 4 rest days (range, 0-5 days). We found that 23 states (48%) did not make distinctions for pitch count rules based on the athlete’s level of competition, age, or grade. We noted a 25% increase in total seasonal pitch counts between the smallest and largest pitch count limit when assuming constant 3-day rest. We found a 53% difference in total seasonal pitch count when rest days varied between 3 and 5 days with a constant 110-pitch limit. Allowing 140 pitches in a 4-day span without a specific rest day requirement resulted in the highest seasonal pitch count (Nevada). There was a 49% difference in maximum seasonal pitch counts between the most and least restrictive states ( P < .001). Submaximum pitch limits resulted in higher seasonal pitch counts than maximum pitch limits in 56% of states. Conclusion: Pitch count rules vary widely by state. Required rest days influenced total seasonal pitch counts more than maximum or submaximum pitch count limits.

Background: Limited English language proficiency in patients undergoing total shoulder arthroplasty (TSA) may make treatment more challenging. Purpose: We sought to investigate the potential association between TSA patients’ use of a language interpreter and 2 outcomes: hospital length of stay (LOS) and discharge disposition. Methods: We conducted a retrospective cohort study comparing LOS and discharge disposition after TSA for patients who required interpreter services and patients who did not at a single institution in an urban setting between 2016 and 2020. Consecutive patients requiring interpreter services who underwent TSA were matched 1:1 to patients who did not require an interpreter by age, body mass index (BMI), sex, and procedure. Multivariate regression models controlling for age, BMI, sex, smoking, opioid use, white or non-white race, procedure, and diagnosis were constructed to determine associations between interpreter use, LOS, and discharge disposition. Results: Forty-one patients were included in each cohort, exceeding the minimum number required per an a priori power analysis. Mean hospital LOS was longer in the interpreter cohort than in the non-interpreter cohort (2.8 ± 2.4 vs 1.8 ± 1.0 days, respectively). Multivariate linear regression demonstrated interpreter use was the strongest predictor of LOS, with the effect estimate indicating an additional 0.88-day LOS per patient. A greater proportion of patients from the interpreter cohort were discharged to an acute/subacute rehabilitation facility than patients from the non-interpreter cohort ( n = 8 [19.5%] vs n = 2 [4.9%], respectively). Patients from the interpreter cohort were 454% more likely to be discharged to acute/subacute rehabilitation facilities. Conclusions: Our retrospective analysis of patients undergoing TSA suggests that the need for interpreter services may be associated with increased LOS and discharge to a facility. More rigorous study is needed to identify the factors that influence these outcomes and to avoid disparities in hospital stay and discharge.

Background: Graft failure after osteochondral allograft transplantation (OCA) of the knee is a devastating outcome, often necessitating subsequent interventions. A comprehensive understanding of the risk factors for failure after OCA of the knee may provide enhanced prognostic data for the knee surgeon and facilitate more informed shared decision-making discussions before surgery. Purpose: To perform a systematic review and meta-analysis of risk factors associated with graft failure after OCA of the knee. Study Design: Systematic review and meta-analysis; Level of evidence, 4. Methods: The PubMed, Ovid/MEDLINE, and Cochrane databases were queried in April 2021. Data pertaining to study characteristics and risk factors associated with failure after OCA were recorded. DerSimonian-Laird binary random-effects models were constructed to quantitatively evaluate the association between risk factors and graft failure by generating effect estimates in the form of odds ratios (ORs) with 95% CIs, while mean differences (MDs) were calculated for continuous data. Qualitative analysis was performed to describe risk factors that were variably reported. Results: A total of 16 studies consisting of 1401 patients were included. The overall pooled prevalence of failure was 18.9% (range, 10%-46%). There were 44 risk factors identified, of which 9 were explored quantitatively. There was strong evidence to support that the presence of bipolar chondral defects (OR, 4.20 [95% CI, 1.17-15.08]; P = .028) and male sex (OR, 2.04 [95% CI, 1.17-3.55]; P = .012) were significant risk factors for failure after OCA. Older age (MD, 5.06 years [95% CI, 1.44-8.70]; P = .006) and greater body mass index (MD, 1.75 kg/m2 [95% CI, 0.48-3.03]; P = .007) at the time of surgery were also significant risk factors for failure after OCA. There was no statistically significant evidence to incontrovertibly support that concomitant procedures, chondral defect size, and defect location were associated with an increased risk of failure after OCA. Conclusion: Bipolar chondral defects, male sex, older age, and greater body mass index were significantly associated with an increased failure rate after OCA of the knee. No statistically significant evidence presently exists to support that chondral defect size and location or concomitant procedures are associated with an increased graft failure rate after OCA of the knee. Additional studies are needed to evaluate these associations.

Background: The International Hip Outcome Tool 12-Item Questionnaire (IHOT-12) has been proposed as a more appropriate outcome assessment for hip arthroscopy populations. The extent to which preoperative patient factors predict achieving clinically meaningful outcomes among patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS) remains poorly understood. Purpose: To determine the predictive relationship of preoperative imaging, patient-reported outcome measures, and patient demographics with achievement of the minimal clinically important difference (MCID), Patient Acceptable Symptom State (PASS), and substantial clinical benefit (SCB) for the IHOT-12 at a minimum of 2 years postoperatively. Study Design: Case-control study; Level of evidence, 3. Methods: Data were analyzed for consecutive patients who underwent hip arthroscopy for FAIS between 2012 and 2018 and completed the IHOT-12 preoperatively and at a minimum of 2 years postoperatively. Fifteen novel machine learning algorithms were developed using 47 potential demographic, clinical, and radiographic predictors. Model performance was evaluated with discrimination, calibration, decision-curve analysis and the brier score. Results: A total of 859 patients were identified, with 685 (79.7%) achieving the MCID, 535 (62.3%) achieving the PASS, and 498 (58.0%) achieving the SCB. For predicting the MCID, discrimination for the best-performing models ranged from fair to excellent (area under the curve [AUC], 0.69-0.89), although calibration was excellent (calibration intercept and slopes: –0.06 to 0.02 and 0.24 to 0.85, respectively). For predicting the PASS, discrimination for the best-performing models ranged from fair to excellent (AUC, 0.63-0.81), with excellent calibration (calibration intercept and slopes: 0.03-0.18 and 0.52-0.90, respectively). For predicting the SCB, discrimination for the best-performing models ranged from fair to good (AUC, 0.61-0.77), with excellent calibration (calibration intercept and slopes: –0.08 to 0.00 and 0.56 to 1.02, respectively). Thematic predictors for failing to achieve the MCID, PASS, and SCB were presence of back pain, anxiety/depression, chronic symptom duration, preoperative hip injections, and increasing body mass index (BMI). Specifically, thresholds associated with lower likelihood to achieve a clinically meaningful outcome were preoperative Hip Outcome Score–Activities of Daily Living 55.6, preoperative IHOT-12 score ≥48.5, preoperative modified Harris Hip Score ≤51.7, age >41 years, BMI ≥27, and preoperative α angle >76.6°. Conclusion: We developed novel machine learning algorithms that leveraged preoperative demographic, clinical, and imaging-based features to reliably predict clinically meaningful improvement after hip arthroscopy for FAIS. Despite consistent improvements after hip arthroscopy, meaningful improvements are negatively influenced by greater BMI, back pain, chronic symptom duration, preoperative mental health, and use of hip corticosteroid injections.

The development of hyponatremia after total joint arthroplasty (TJA) may lead to several adverse events and is associated with prolonged inpatient length of stay as well as increased hospital costs. The purpose of this study was to develop and internally validate machine learning algorithms for predicting hyponatremia after TJA.A consecutive cohort of 30,703 TJA patients from an institutional registry at a large, tertiary academic hospital were included. A total of 19 potential predictor variables were collected. Hyponatremia was defined as a serum sodium concentration of135 mEq/L. Five machine learning algorithms were developed using a training set and internally validated using an independent testing set. Algorithm performance was evaluated through discrimination, calibration, decision-curve analysis, and Brier score.The charts of 30,703 patients undergoing TJA were reviewed. Of those patients, 5,480 (17.8%) developed hyponatremia postoperatively. A combination of 6 variables were demonstrated to optimize algorithm prediction: preoperative serum sodium concentration, age, intraoperative blood loss, procedure time, body mass index (BMI), and American Society of Anesthesiologists (ASA) score. Threshold values that were associated with greater hyponatremia risk were a preoperative serum sodium concentration of ≤138 mEq/L, an age of ≥73 years, an ASA score of2, intraoperative blood loss of407 mL, a BMI of ≤26 kg/m2, and a procedure time of111 minutes. The stochastic gradient boosting (SGB) algorithm demonstrated the best performance (c-statistic: 0.75, calibration intercept: -0.02, calibration slope: 1.02, and Brier score: 0.12). This algorithm was turned into a tool that can provide real-time predictions (https://orthoapps.shinyapps.io/Hyponatremia_TJA/).The SGB algorithm demonstrated the best performance for predicting hyponatremia after TJA. The most important factors for predicting hyponatremia were preoperative serum sodium concentration, age, intraoperative blood loss, procedure time, BMI, and ASA score. A real-time hyponatremia risk calculator was developed, but it is imperative to perform external validation of this model prior to using this calculator in clinical practice.Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Introduction Patients who undergo total shoulder arthroplasty (TSA) may experience substantial postoperative pain, which may negatively impact patient satisfaction, lead to greater narcotic consumption, and impair early rehabilitation. The purpose of this study was to perform a systematic review of randomized controlled trials (RCTs) to evaluate the effect of analgesia methods on postoperative (1) pain, (2) opioid use, (3) length of stay (LOS), and (4) adverse events in patients undergoing TSA, reverse TSA, and hemiarthroplasty. Methods A systematic review was performed by querying PubMed, Web of Science, and Cochrane Controlled Register of Trials for studies on analgesic interventions following shoulder arthroplasty. Data pertaining to pain scores, narcotic requirements, LOS, and complications were extracted. Results Eight studies (67%) included continuous interscalene block (CISB) with an indwelling catheter, six studies (50%) included a single-injection interscalene block (ISB), five studies (42%) included local infiltration with liposomal bupivacaine, four studies (33%) included local infiltration with anesthetics other than liposomal bupivacaine, one study (8%) included brachial plexus blocks other than ISB. ISB provided better pain relief than local infiltration in the immediate postoperative period (0-8 hours) as seen in 5/7 (71.4%) studies, but pain levels became similar subsequently. CISB may be superior to single-injection ISB for pain control at the 24-hour time point. The lowest narcotic requirement was seen in the CISB groups postoperatively but was variable. No pain management modalities significantly impacted LOS. A greater number of adverse events were seen with CISB. Discussion Single-injection ISB and CISB appear to offer greater pain relief in the immediate postoperative period compared to local infiltration with liposomal bupivacaine or other anesthetics. CISB provided sustained pain relief at 24 hours compared to other modalities. Analgesic benefit of CISB should be considered in the context of greater cost and potential for more frequent adverse events. Level of Evidence Level I; Systematic Review

To synthesize the epidemiology, cause, management, and return to sport (RTS) outcomes of ilium avulsion fractures sustained during sporting activities in young athletes. Studies reporting on athletes18 years old sustaining an avulsion fracture along the ilium [injury to the anterior superior or inferior iliac spine (ASIS or AIIS), or the iliac crest (IC)], and the athlete's RTS status were included. RTS was analyzed by injury acuity, location, mechanism of injury, and management, whereas complications were recorded. Seventy studies comprising 286 avulsions (169 ASIS, 87 AIIS, and 30 IC) were included. The mean age of athletes was 14.5 + 1.3 years (range, 8-18 years). Sprinting (n = 103/286; 36.0%) and soccer (n = 97/286; 33.9%) were the most common sports during which injuries occurred. A total of 96.5% (n = 276/286) of athletes reported successful RTS at an average of 16.2 + 19.3 weeks. The RTS rate for patients sustaining ASIS, AIIS, and IC avulsions was 95.3, 97.7, and 100%, respectively. Acute trauma was responsible for 89.8% (n = 158/176) of injuries, which demonstrated a significantly faster (13.3 + 9.3 weeks) and higher RTS rate (99.4%) compared with those with chronic avulsions (74.4 + 40.9 weeks and 83.3%, respectively). Those with complications (18.2%) had a significantly lower RTS rate (90.4%) and longer recovery (23.7 weeks) compared with athletes without complications (97.9% and 14.5 weeks, respectively). Outcomes were not significantly different based on sex or management. However, chronic avulsions and postoperative complications sustained worse RTS results. An accurate and timely diagnosis is crucial when presented with these rare injuries to avoid increasing the chronicity of injury.

Specialty: Orthopedics Traumatology Objective: Rare disease Background: Posterior meniscal root avulsions can cause meniscal extrusion, joint space narrowing, and progressive knee arthritis. Iatrogenic posterior meniscal root avulsions after malpositioning of the transtibial tunnels during an-terior cruciate ligament (ACL) reconstruction can account for poor long-term outcomes seen in some patients following ACL reconstruction. Therefore, correct transtibial tunnel placement during ACL reconstruction is es-sential to avoid iatrogenic meniscal damage. Case Report: A 32-year-old man presented with 1 year of right knee pain and instability following a non-contact twisting injury sustained while playing soccer. An ACL tear with no meniscal involvement was diagnosed at an outside institution. A double-bundle reconstruction was performed at that time. Three months after surgery, a medial partial meniscectomy was performed after a medial meniscal tear and failure to reduce initial symptoms dur-ing the index procedure. Advanced imaging at our institution 6 months later demonstrated an iatrogenic later-al posterior meniscal root avulsions after malpositioning of the transtibial tunnels. Given the ACL graft integ-rity upon arthroscopic evaluation, the root tear was repaired using a 2-tunnel transtibial pull-out technique. Advanced imaging 1 year after surgery showed a well-maintained meniscal repair with no extrusion. Conclusions: Accurate transtibial tunnel placement during ACL reconstructive surgery is vital to avoid meniscal root detach-ment and the associated complications resulting in poor patient outcomes from this iatrogenic injury. Clinicians treating patients with a history of cruciate ligament reconstruction presenting with postoperative pain and in-stability should consider this pathology in their differential diagnosis.

Supervised learning is the most common form of machine learning utilized in medical research. It is used to predict outcomes of interest or classify positive and/or negative cases with a known ground truth. Supervised learning describes a spectrum of techniques, ranging from traditional regression modeling to more complex tree boosting, which are becoming increasingly prevalent as the focus on "big data" develops. While these tools are becoming increasingly popular and powerful, there is a paucity of literature available that describe the strengths and limitations of these different modeling techniques. Typically, there is no formal training for health care professionals in the use of machine learning models. As machine learning applications throughout medicine increase, it is important that physicians and other health care professionals better understand the processes underlying application of these techniques. The purpose of this study is to provide an overview of commonly used supervised learning techniques with recent case examples within the orthopedic literature. An additional goal is to address disparities in the understanding of these methods to improve communication within and between research teams.

Background: Primary repair of the anterior cruciate ligament (ACL) confers an alternative to ACL reconstruction in appropriately selected patients. Purpose: To prospectively assess survivorship and to define the clinically meaningful outcomes after ACL repair. Study Design: Case series; Level of evidence, 4. Methods: Included were consecutive patients with Sherman grade 1-2 tears who underwent primary ACL repair with or without suture augmentation between 2017 and 2019. Patient-reported outcomes (Lysholm, Tegner, International Knee Documentation Committee, Western Ontario and McMaster Universities Osteoarthritis Index, and Knee injury and Osteoarthritis Outcome Score [KOOS] subscales) were collected preoperatively and at 6 months, 1 year, and 2 years postoperatively. The minimal clinically important difference (MCID) was calculated using a distribution-based method, whereas the Patient Acceptable Symptom State (PASS) and substantial clinical benefit (SCB) were calculated using an anchor-based method. Plain radiographs and magnetic resonance imaging (MRI) were obtained at 6 months, 1 year, and 2 years postoperatively. Results: A total of 120 patients were included. The overall failure rate was 11.3% at 2 years postoperatively. Changes in outcome scores required to achieve the MCID ranged between 5.1 and 14.3 at 6 months, 4.6 and 8.4 at 1 year, and 4.7 and 11.9 at 2 years postoperatively. Thresholds for PASS achievement ranged between 62.5 and 89 at 6 months, 75 and 89 at 1 year, and 78.6 and 93.2 at 2 years postoperatively. Threshold scores (absolute/change based) for achieving the SCB ranged between 82.8 and 96.4/17.7 and 40.1 at 6 months, between 94.7 and 100/23 and 45 at 1 year, and between 95.3 and 100/29.4 and 45 at 2 years. More patients achieved the MCID and PASS at 1 year compared with 6 months and 2 years. For SCB, this trend was also observed for non-KOOS outcomes, while for KOOS subdomains, more patients achieved the SCB at 2 years. High-intensity signal of the ACL repair (odds ratio [OR], 31.7 [95% CI, 1.5-73.4]; P = .030) and bone contusions on MRI (OR, 4.2 [95% CI, 1.7-25.2]; P = .041) at 1 year postoperatively were independently associated with increased risk of ACL repair failure. Conclusion: The rate of clinically meaningful outcome improvement was high early after ACL repair, with the greatest proportion of patients achieving the MCID, PASS, and SCB at 1 year postoperatively. Bone contusions involving the posterolateral tibia and lateral femoral condyle as well as high repair signal intensity at 1 year postoperatively were independent predictors of failure at 2 years postoperatively.

Background: Machine learning (ML) has emerged as a method to determine patient-specific risk for prolonged postoperative opioid use after orthopedic procedures. Purpose: We sought to analyze the efficacy and validity of ML algorithms in identifying patients who are at high risk for prolonged opioid use following orthopedic procedures. Methods: PubMed, EMBASE, and Web of Science Core Collection databases were queried for articles published prior to August 2021 for articles applying ML to predict prolonged postoperative opioid use following orthopedic surgeries. Features pertaining to patient demographics, surgical procedures, and ML algorithm performance were analyzed. Results: Ten studies met inclusion criteria: 4 spine, 3 knee, and 3 hip. Studies reported postoperative opioid use over 30 to 365 days and varied in defining prolonged use. Prolonged postsurgical opioid use frequency ranged from 4.3% to 40.9%. C-statistics for spine studies ranged from 0.70 to 0.81; for knee studies, 0.75 to 0.77; and for hip studies, 0.71 to 0.77. Brier scores for spine studies ranged from 0.039 to 0.076; for knee, 0.01 to 0.124; and for hip, 0.052 to 0.21. Seven articles reported calibration intercept (range: –0.02 to 0.16) and calibration slope (range: 0.88 to 1.08). Nine articles included a decision curve analysis. No investigations performed external validation. Thematic predictors of prolonged postoperative opioid use were preoperative opioid, benzodiazepine, or antidepressant use and extremes of age depending on procedure population. Conclusions: This systematic review found that ML algorithms created to predict risk for prolonged postoperative opioid use in orthopedic surgery patients demonstrate good discriminatory performance. The frequency and predictive features of prolonged postoperative opioid use identified were consistent with existing literature, although algorithms remain limited by a lack of external validation and imperfect adherence to predictive modeling guidelines.

Background: Biodegradable subacromial balloon spacers (SBSs) have become increasingly used for the treatment of massive irreparable rotator cuff tears given their theorized clinical benefits; however, the relationship between biomechanical functions of the balloon spacer and clinical benefits remains unclear. Purpose: To perform a systematic review and meta-analysis of controlled laboratory studies investigating the use of SBSs for massive irreparable rotator cuff tears. Study Design: Systematic review and meta-analysis; Level of evidence, 4. Methods: PubMed, OVID/Medline, and Cochrane databases were queried in July 2022 for biomechanical data pertaining to SBS implantation in cadaveric models of irreparable rotator cuff tears. Random-effects meta-analysis of continuous outcomes using the DerSimonian-Laird method was performed to estimate pooled-treatment effect sizes between the irreparable rotator cuff tear state and the state in which an SBS was implanted. Data reported variably or in formats not amenable to analysis were presented descriptively. Results: Five studies involving 44 cadaveric specimens were included. At 0° of shoulder abduction, SBS implantation resulted in a mean inferior humeral head translation of 4.80 mm (95% CI, 3.20-6.40; P < .001) relative to the irreparable rotator cuff tear state. This decreased to 4.39 mm and 4.35 mm at 30° and 60° of abduction, respectively. At 0° of abduction, implantation of an SBS was associated with a 5.01-mm (95% CI, 3.56-6.46, P < .001) anterior translation of the glenohumeral center of contact pressure relative to the irreparable tear state. This translation changed to 5.11 mm and 5.49 mm at 30° and 60° of abduction. In 2 studies, SBS implantation restored the glenohumeral contact pressure to that of the intact state and significantly reduced subacromial pressure distribution over a rotator cuff repair state. In 1 study, a high balloon fill volume (40 mL) resulted in a significant 10.3 ± 1.4–mm more anterior humeral head position relative to the intact cuff state. Conclusion: SBS implantation in cadaveric models of irreparable rotator cuff tears results in significant improvements in humeral head position at 0°, 30°, and 60° of shoulder abduction. Balloon spacers may also improve glenohumeral and subacromial contact pressures, although insufficient evidence currently exists to corroborate these findings. High balloon fill volumes (40 mL) may confer supraphysiologic anteroinferior translation of the humeral head.

Background: While medial meniscocapsular tears (ramp lesions) are commonly associated with isolated anterior cruciate ligament injuries, there are limited descriptions of these meniscal injuries in multiligament knee injuries (MLKIs). Purpose: To (1) retrospectively evaluate preoperative magnetic resonance imaging (MRI) scans for the presence of ramp lesions in patients surgically treated for acute grade 3 combined posterolateral corner (PLC) knee injuries and (2) determine if a preoperative posteromedial tibial plateau (PMTP) bone bruise is associated with the presence of preoperative ramp lesions on MRI in these same patients. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Data on consecutive patients at a level 1 trauma center with MLKIs between 2001 and 2021 were retrospectively reviewed. Only patients with acute grade 3 combined PLC injuries who received an MRI scan within 30 days of injury were assessed. Two musculoskeletal radiologists retrospectively reviewed each patient’s preoperative MRI for evidence of ramp lesions and bone bruises. Intraclass correlation coefficients (ICCs) were used to calculate reliability among the reviewers. Multivariate analysis was used to evaluate the relationship between PMTP bruising and the presence of a ramp lesion on MRI. Results: A total of 68 patients (79.4% male; mean age, 33.8 ± 13.7 years) with an acute grade 3 combined PLC injury were included in the study. On MRI, the ICCs for detection of ramp lesions and PMTP bone bruising were 0.921 and 0.938, respectively. Medial meniscal ramp lesions were diagnosed in 18 of 68 (26.5%) patients. Eleven of 18 (61.1%) patients with ramp lesions also showed evidence of PMTP bruising, while 13 of 50 (26.0%) patients without ramp lesions had PMTP bruising ( P = .008). When controlling for age and sex, PTMP bruising was significantly associated with the presence of a ramp lesion in combined PLC injuries (odds ratio, 4.62; P = .012). Conclusion: Preoperative medial meniscal ramp lesions were diagnosed on MRI in 26.5% of patients with acute grade 3 combined PLC injuries. PMTP bone bruising was significantly associated with the presence of a ramp lesion on MRI. These findings reinforce the need to assess for potential ramp lesions at the time of multiligament reconstruction.

To assess the clinical utility of preoperative magnetic resonance imaging (MRI) and quantify the delay in surgical care for patients aged ≤40 years undergoing primary hip arthroscopy with history, physical examination, and radiographs concordant with femoroacetabular impingement syndrome (FAIS).From August 2015 to December 2020, 1,786 consecutive patients were reviewed from the practice of 1 fellowship-trained hip arthroscopist. Inclusion criteria were FAIS, primary surgery, and age ≤40 years. Exclusion criteria were MRI contraindication, reattempt of conservative management, or concomitant periacetabular osteotomy. After nonoperative treatment options were exhausted and a surgical plan was established, patients were stratified by those who presented with versus without MRI. Those without existing MRI received one, and any deviations from the surgical plan were noted. All preoperative MRIs were compared with office evaluation and intraoperative findings to assess agreement. Demographic data, Hip Disability and Osteoarthritis Outcome Score (HOOS)-Pain, and time from office to MRI or arthroscopy were recorded.Of the patients indicated by history, physical examination, and radiographs alone (70% female, body mass index 24.8 kg/mOnce indicated for surgery based on history, physical examination, and radiographs, preoperative MRI did not alter the surgical plan for patients aged ≤40 years with FAIS undergoing primary hip arthroscopy. Moreover, preoperative MRI delayed time to arthroscopy. The necessity of routine preoperative MRI in the young primary FAIS population should be challenged.

There has been a considerable increase in total joint arthroplasty (TJA) research using machine learning (ML). Therefore, the purposes of this study were to synthesize the applications and efficacies of ML reported in the TJA literature, and to assess the methodological quality of these studies.PubMed, OVID/MEDLINE, and Cochrane libraries were queried in January 2021 for articles regarding the use of ML in TJA. Study demographics, topic, primary and secondary outcomes, ML model development and testing, and model presentation and validation were recorded. The TRIPOD (Transparent Reporting of a Multivariable Prediction Model for Individual Prognosis or Diagnosis) guidelines were used to assess the methodological quality.Fifty-five studies were identified: 31 investigated clinical outcomes and resource utilization; 11, activity and motion surveillance; 10, imaging detection; and 3, natural language processing. For studies reporting the area under the receiver operating characteristic curve (AUC), the median AUC (and range) was 0.80 (0.60 to 0.97) among 26 clinical outcome studies, 0.99 (0.83 to 1.00) among 6 imaging-based studies, and 0.88 (0.76 to 0.98) among 3 activity and motion surveillance studies. Twelve studies compared ML to logistic regression, with 9 (75%) reporting that ML was superior. The average number of TRIPOD guidelines met was 11.5 (range: 5 to 18), with 38 (69%) meeting greater than half of the criteria. Presentation and explanation of the full model for individual predictions and assessments of model calibration were poorly reported (30%).The performance of ML models was good to excellent when applied to a wide variety of clinically relevant outcomes in TJA. However, reporting of certain key methodological and model presentation criteria was inadequate. Despite the recent surge in TJA literature utilizing ML, the lack of consistent adherence to reporting guidelines needs to be addressed to bridge the gap between model development and clinical implementation.

Focal chondral defects (FCD) of the knee are common sources of pain and dysfunction in young patients with high activity demands. Both the understanding of the cause of FCDs and the surgical management of these defects has exponentially grown. This is reflected in the number of surgical procedures performed for FCD, which now approximates 200,000 annually. This fact is also apparent in the wide variety of surgical approaches to FCD that now exist, from simple arthroscopic debridement to complex restorative procedures such as osteochondral allograft transplantation. Given the prevalence of FCD and increased attention on treating these lesions, a comprehensive understanding of management from diagnosis to rehabilitation is imperative for the treating surgeon. This chapter presents current concepts in the treatment of FCD, provides an algorithmic approach to selecting interventions to address FCD, and subsequently describes each commonly used surgical technique in the management of these chondral defects, with corresponding clinical outcomes.