Camp, Christopher L.

Objectives: The number of medial ulnar collateral ligament (MUCL) reconstructions are increasing. The epidemiology surrounding revision MUCL reconstructions in professional baseball players has not been well defined. The purpose of this study was to report the epidemiology of revision MUCL reconstruction in professional baseball players. The authors hypothesized that the number of revision MUCL reconstructions would increase over time and that the return to sport rate at the same level of play would be less than 70%. Methods: All professional baseball pitchers who underwent revision MUCL reconstruction between 2010-2023 were identified using the MLB Health and Injury Tracking System (HITS). Rate of return and time to return to play (RTP) and return to same level of play (RTSL) was recorded and analyzed for pitchers with a minimum follow up of 2 years. Surgical variables including technique and graft choice were also recorded. Results: Overall, 191 pitchers (avg age 26.0 years), underwent revision MUCL reconstruction. The average time between primary and revision surgery was 1,381 days (45 months). 130 (68%) of these players were MLB pitchers and the other 61 (32%) were MiLB pitchers. 59% of pitchers were able to RTSL at an average of 604 ± 250 days after surgery. 2023 was the year with most revision MUCL reconstructions (n = 27) and the fewest reconstructions were performed in 2010 and 2011 (n = 4). Monthly distribution demonstrates the highest surgery months to be May (17%), June (20%), and July (17%). Hamstring tendon autograft was found to be the most commonly used graft source (n = 90, 47%), compared to palmaris longus autograft (n = 67, 35%). No significant differences were found in the types of grafts used over time ( P = .238 for palmaris and P = .133 for hamstring). In terms of tunnel configuration, both the Modified Jobe and Docking techniques were used in equal occurrence (n = 70, 37%) Conclusions: Following revision MUCL reconstruction, only 72% of professional baseball pitchers were able to return to play at any level at an average of 556 days (18 months), and only 59% were able to return to the same level of play at an average of 604 days (20 months). The average time between primary and revision MUCL reconstruction was 45 months (3.75 years). Pitchers should be counseled on the relatively low RTSL rate and the prolonged time to RTSL.

Objectives: The medial ulnar collateral ligament (MUCL) is the primary stabilizer of valgus forces across the elbow. Injury to the MUCL has a large impact on the throwing athlete, particularly in baseball. The incidence of MUCL injury in baseball pitchers is on the rise. Surgical treatment and rehabilitation is evolving to improve outcomes and improve return to sport time frames. The purpose of this study was to highlight the trends in MUCL repair and reconstruction in professional baseball pitchers, describe relevant outcomes such as return to any level of play (RTP) for surgical repair and reconstruction, and distinguish what factors might impact these outcomes. The authors hypothesize that primary and revision MUCL surgery is increasing with revision surgery requiring the greatest time to RTP. Methods: The Major League Baseball (MLB) Health and Injury Tracking System (MLB HITS) database was used to procure data during the targeted study period (2010 – 2023). All professional pitchers who underwent MUCL surgery within the study period were included. Variables analyzed included age, career length, and level of play. Surgical variables included date and type of procedure, RTP status, time required to RTP, return to same level of play (RTSL), career length before and after surgery, number of revision surgeries, and time between surgeries. Successful RTP was designated if a pitcher had returned in at least one professional game after index surgery. Analyses of trends over time were performed. The year 2020 was considered an outlier and omitted from the analysis of trends due to the coronavirus pandemic which limited games played. Results: A total of 2,287 pitchers underwent MUCL surgery during the study period (Table 1). The annual number of MUCL surgeries on all pitchers increased year over year (R 2 = 0.821, p < 0.001), as did the annual number of reconstructions with internal brace (IB) augmentation (R 2 = 0.896, p < 0.001) (Figure 1). The RTP rate (93%) for MLB pitchers was significantly higher compared to the RTSL rate (71%, P < 0.001). This difference was not observed in Minor League Baseball (MiLB) (RTP 76% vs. RTSL 74%, P = 0.142) (Figure 2). The percentage of players who RTP after revision surgery was significantly lower compared to primary surgery (71%vs. 80% respectively, P = 0.020). Mean time to RTP is significantly shorter (470 ± 135 days) compared to the mean time to RTSL (499 ± 153 days, P < 0.001) (Figure 3). The annual number of revision MUCL surgeries on all pitchers increased year over year as well (R 2 = 0.322, p = 0.043). Conclusions: MUCL surgery continues to increase, also leading to increasing numbers of revisions in professional pitchers. Overall, 80% of pitchers were able to RTP at a mean of 470 days (15.5 months), while only 71% were able to RTSL at a mean of 499 days (16.5 months), but this varied based on level of play. Surgical techniques continue to evolve as MUCL repairs and reconstructions with IB augmentation have increased significantly in recent years. This study will help guide athlete expectations and surgeon decision-making.

Background: Treatment decisions in patients with anterior cruciate ligament (ACL) injuries are influenced by multiple factors, such as the desire to return to sports or symptomatic instability. Identifying the differential treatment effect of ACL reconstruction (ACLR) compared with nonoperative management on a patient-specific level can inform surgical decision-making. Hypothesis: Unsupervised machine learning can identify distinct patient subgroups based on outcome achievement after ACL injury, and ACLR will exert a protective effect on the development of posttraumatic osteoarthritis (PTOA) over nonoperative management. Study Design: Cohort study; Level of evidence, 3. Methods: A longitudinal populational registry identified patients with ACL injuries from 1990 to 2016 with a minimum 7.5-year follow-up. An unsupervised random forest algorithm was utilized to develop and validate patient subgroups. Treatment effects of ACLR on outcomes were analyzed using a machine learning causal inference estimator. Patient subgroup membership was incorporated into a multivariable logistic regression to identify factors predictive of optimal outcomes. Results: A total of 923 patients (785 primary ACLR, 138 nonoperative) were included. The random forest algorithm arrived at an optimal partition of 2 subgroups, with 653 patients in the optimal outcome subgroup (368 male [56.4%]; mean age, 26.0 ± 10.2 years; mean body mass index [BMI], 26.5 ± 4.30) and 270 patients in the suboptimal outcome subgroup (152 male [56.3%]; mean age, 35.0 ± 10.1 years; mean BMI, 30.5 ± 5.54). The latter group demonstrated significantly increased rates of secondary meniscal injury, development of symptomatic PTOA, and progression to total knee arthroplasty (TKA) at the final follow-up (all P < .01). In the optimal outcome subgroup, ACLR had significantly protective treatment effects on the risk of secondary meniscal injury (average treatment effect [ATE], 61%), contralateral ACL injury (ATE, 8%), symptomatic PTOA (ATE, 16%), and progression to TKA (ATE, 6%) (all P < .01). Conversely, in the suboptimal outcome subgroup, ACLR only protected against symptomatic PTOA (ATE, 11%) and progression to TKA (ATE, 8%) (both P < .01). Conclusion: Two clinically meaningful subgroups were identified from retrospectively collected data and found to experience differential treatment responses after ACL injuries. ACLR decreased the rate of development of PTOA and TKA in both subgroups but was not as effective in preventing secondary meniscal injuries or contralateral ACL injuries in patients who were older, heavier, or had concomitant medial meniscus injuries.

Background: Injuries of the medial ulnar collateral ligament (MUCL) among baseball pitchers are increasing. Surgical treatment is evolving to optimize outcomes. Purpose/Hypothesis: This study’s purpose was to highlight trends in MUCL repair and reconstruction in professional pitchers, describe outcomes such as return to any level of play (RTP), and identify factors impacting these outcomes. It was hypothesized that primary and revision MUCL surgery is increasing, with revision surgery requiring greater RTP time. Study Design: Case series; Level of evidence, 4. Methods: The Major League Baseball (MLB) Health and Injury Tracking System database was used to procure data during the study period (2010-2023). All professional pitchers who underwent MUCL surgery during this period were included. RTP was defined as a pitcher returning to at least 1 professional game after index surgery. Return to the same level of play (RTSL) was defined as return to at least 1 game in the same league of play as before surgery. Because of the coronavirus pandemic, the year 2020 was considered an outlier and omitted from time-trend analysis. Results: A total of 2281 pitchers who underwent MUCL surgery during the study period were included for analysis. The number of MUCL surgeries for pitchers increased yearly ( R 2 = 0.821; P < .001), as did the number of reconstructions with internal brace augmentation ( R 2 = 0.896; P < .001). The RTP rate for MLB pitchers was significantly higher than the RTSL rate (93% vs 71%; P < .001). This difference was not observed in Minor League Baseball (MiLB) pitchers (RTP 76% vs RTSL 74%; P = .142). RTP rates after revision surgery were lower than those after primary surgery (71% vs 80%; P = .020). The mean time to RTP was shorter (470 ± 135 days) than the mean time to RTSL (499 ± 153 days; P < .001). Conclusion: The incidence of MUCL surgery and revision surgery is increasing among professional pitchers. Overall, 79% of pitchers returned to any level of play at a mean of 470 days, while 74% returned to the same level of play at a mean of 499 days, but this varied based on level of play. This study will guide athlete expectations and surgeon decision-making.

Background: Major League Baseball (MLB) recently instituted a combine for their prospective players. Purpose/Hypothesis: The purpose of this study was to report initial epidemiological findings for both physical examination and imaging findings for the MLB Combine. It was hypothesized that most players would have no significant abnormal physical examination findings, but most would have abnormal findings on their shoulder and elbow magnetic resonance imaging (MRI) scans. Study Design: Descriptive epidemiology study. Methods: All players who attended the 2023 MLB Combine were included. History was taken and physical examination was performed by an MLB team physician, and MRI of the shoulder, elbow, cervical spine, and lumbar spine was performed on all players and read by 1 of 2 musculoskeletal radiologists. Physical examination notes and imaging reports were reviewed by the authors and recorded. Data were analyzed separately for pitchers and position players. Results: Overall, 219 players (112 pitchers [51%], 107 position players [49%]) were included. The mean age was 20.4 ± 1.5 years. The majority of players (95%) had no current pain or limitations; 54 players (25%) had a history of previous surgery. For pitchers, 18% underwent previous elbow surgery. With regard to MRI, >80% of pitchers had some abnormality within their ulnar collateral ligament (UCL), the majority of which was UCL scarring/remodeling. 70% of pitchers and 60% of position players had evidence of an olecranon osteophyte. Increased signal within the ulnar nerve was common in pitchers (40%) but rare in position players (4%). For the shoulder, 95% of pitchers and 93% of position players had some rotator cuff abnormality (often tendinosis within the supraspinatus and infraspinatus muscles). Also, 75% of pitchers had MRI evidence of a superior labrum anterior to posterior (SLAP) tear, while 24% of position players demonstrated this. Lumbar spine MRI showed that 47% of position players had a disk protrusion and 46% had a previous pars fracture. Conclusion: Most baseball players who participated in the 2023 MLB Combine had MRI evidence of rotator cuff abnormalities, and many showed evidence of an olecranon osteophyte. Eighteen percent of pitchers had a previous history of elbow surgery. The majority of pitchers had some abnormality within their UCL and evidence of a SLAP tear on MRI scans.

Context: There is need for an up-to-date comprehensive review of baseball interval throwing programs in the literature. Objective: To (1) understand the origin and basis of interval throwing programs; (2) evaluate the content of programs in the peer-reviewed literature including target audience, initiation criteria, throwing specifics, arm care, and performance evaluation metrics; (3) classify these variables as well defined, ambiguous, or missing; and (4) analyze variability in key aspects including starting criteria, length, progression, and completion criteria. Data Sources: Medline, Embase, Cochrane Reviews, Web of Science, and Scopus Study Selection: The full text of studies, in English, had to be available. Included studies had to contain a complete interval throwing program designed for baseball players. Study Design: Systematic review. Level of Evidence: Level 4. Data Extraction: Initial screening was conducted based on article title and abstract. Full text of the remaining articles was evaluated for fulfillment of inclusion criteria. Results: Nine studies initially met inclusion criteria. The programs’ comprehensiveness was poor, with a mean Interval Throwing Program Checklist score of 20 (range 14-23) on a scale of 0 to 30. There were a variety of components, including progressive long toss, weighted ball, and throwing mechanics exercises. The programs identified had significant heterogeneity in duration, intensity, progression, and focus. Overall, there was a significant lack of attempts at validation or formal study of efficacy for published throwing programs. Conclusion: Current published interval throwing programs are mostly variations of an original program published many years ago and were based on principles of progressive loading with pain as sign of injury that should be monitored carefully. However, these programs have minimal clinical validation and objective measures to quantify their effectiveness. This work identifies several limitations in the current literature and can serve as a foundation for future development of evidence-based interval throwing programs.

Background: Nonoperative and operative management techniques after anterior cruciate ligament (ACL) injury are both appropriate treatment options for selected patients. However, the subsequent development of posttraumatic knee osteoarthritis (PTOA) remains an area of active study. Purpose: To compare the risk of PTOA between patients treated without surgery and with ACL reconstruction (ACLR) after primary ACL disruption using a machine learning causal inference model. Study Design: Cohort study; Level of evidence, 3. Methods: A geographic database identified patients undergoing ACLR between 1990 and 2016 with minimum 7.5-year follow-up. Variables collected include age, sex, body mass index, activity level, occupation, relevant comorbid diagnoses, radiographic findings, injury characteristics, and clinical course. Treatment effects of ACLR on the development of PTOA and progression to total knee arthroplasty (TKA) were analyzed with machine learning models (MLMs) in a causal inference estimator (targeted maximum likelihood estimation, TMLE), while controlling for confounders. Results: The study included 1194 patients with a minimum follow-up of 7.5 years, among whom 974 underwent primary reconstruction and 220 underwent nonoperative treatment. A total of 215 (22%) patients developed symptomatic PTOA in the ACLR group compared with 140 (64%) in the nonoperative treatment group ( P < .001), whereas 25 (3%) patients underwent TKA in the ACLR group compared with 50 (23%) in the nonoperative treatment group ( P < .001). Patients in the ACLR group had delayed TKA compared with patients in the nonoperative treatment group (193.4 vs 166.0 months, respectively; P = .02). TMLE evaluation revealed that reconstruction decreased the risk of PTOA by 11% (95% CI, 8%-13%; P < .001) compared with nonoperative treatment but did not demonstrate a significant effect on the rate of progression to TKA. Survival analysis with random forest algorithm demonstrated significant delay to the onset of PTOA as well as time to progression of TKA in patients undergoing ACLR. Additional risk factors for the development of PTOA, irrespective of treatment, included older age at injury, greater body mass index, total number of arthroscopic knee surgeries, and residual laxity at follow-up. Conclusion: MLMs in a causal inference estimator found ACLR to exert a significant treatment effect in reducing the rate of development of PTOA by 11% compared with nonoperative treatment. ACLR also delayed the onset of PTOA and progression to TKA.

Background: The number of medial ulnar collateral ligament (MUCL) reconstructions is increasing. The epidemiology surrounding revision MUCL reconstructions in professional baseball players has not been well defined. Purpose/Hypothesis: The purpose was to report the epidemiology of revision MUCL reconstruction in professional baseball players. The authors hypothesized that the number of revision MUCL reconstructions has increased over time and that the rate of return to sport at the same level of play is <70%. Study Design: Case series; Level of evidence, 4. Methods: All professional baseball pitchers who underwent revision MUCL reconstruction between 2010 and 2023 were identified using the Major League Baseball Health and Injury Tracking System. Rates of return to play, time to return to play, and return to same level of play were recorded and analyzed for pitchers with a minimum follow-up of 2 years. Surgical variables, including technique and graft choice, were also recorded. Results: Overall 191 pitchers (mean age, 26.0 years) underwent revision MUCL reconstruction. The mean time between primary and revision surgery was 1381 days (45 months). Of these players, 130 (68%) were Minor League Baseball pitchers. Hamstring tendon autograft was the most commonly used graft source (n = 90; 47%) when compared with palmaris longus autograft (n = 67; 35%). In terms of tunnel configuration, the modified Jobe and docking techniques were used in equal occurrence (n = 70; 37%). After revision MUCL reconstruction, only 72% of professional baseball pitchers were able to return to play at any level at a mean 556 days (18 months), and only 58% were able to return to the same level of play at a mean 604 days (20 months). The mean time between primary and revision MUCL reconstruction was 45 months (3.75 years). Conclusion: Revision MUCL surgery continues to be a challenging problem, where the procedure is complex, rehabilitation timelines are prolonged, and outcomes are not always optimal. Accordingly, the authors recommend that these procedures be performed by surgeons with high levels of experience.

Abstract Purpose Developing large‐scale, standardized radiographic registries for anterior cruciate ligament (ACL) injuries with artificial intelligence (AI) tools can enhance personalized orthopaedics. We propose deploying Artificial Intelligence for Knee Imaging Registration and Analysis (AKIRA), a trio of deep learning (DL) algorithms, to automatically classify and annotate radiographs. We hypothesize that algorithms can efficiently organize radiographs based on laterality, projection, identify implants and classify osteoarthritis (OA) grade. Methods A collection of 20,836 knee radiographs from all time points of treatment (mean orthopaedic follow‐up 70.7 months; interquartile range [IQR]: 6.8–172 months) were aggregated from 1628 ACL‐injured patients (median age 26 years [IQR: 19–42], 57% male). Three DL algorithms (EfficientNet, YOLO [You Only Look Once] and Residual Network) were employed. Radiograph laterality and projection (anterior‐posterior [AP], lateral, sunrise, posterior‐anterior, hip–knee–ankle and Camp‐Coventry intercondylar [notch]) were labelled by a DL model. Manually provided labels of metal fixation implants were used to develop a DL object detection algorithm. The degree of OA, both as measured by specific Kellgren–Lawrence (KL) grades, as well as based on a binarized label of OA (defined as KL Grade ≥2), on standing AP radiographs were classified using a DL algorithm. Individual model performances were evaluated on a subset of images prior to the deployment of AKIRA to registry construction using all ACL radiographs. Results The classification algorithms showed excellent performance in classifying radiographic laterality (F1 score: 0.962–0.975) and projection (F1 score: 0.941–1.0). The object detection algorithm achieved high precision–recall (area under the precision‐recall curve: 0.695–0.992) for identifying various metal fixations. The KL classifier reached concordances of 0.39–0.40, improving to 0.81–0.82 for binary OA labels. Sequential deployment of AKIRA following internal validation processed and labelled all 20,836 images with the appropriate views, implants, and the presence of OA within 88 min. Conclusion AKIRA effectively automated the classification and object detection in a large radiograph cohort of ACL injuries, creating an AI‐enabled radiographic registry with comprehensive details on laterality, projection, implants and OA. Study Design Cross‐sectional study. Level of Evidence Level IV.

Background: Anterior cruciate ligament reconstruction (ACLR) is one of the most common orthopaedic procedures and one of the most well studied. Despite extensive research dedicated to ACLR, there is limited understanding of how chronic inflammatory systemic diseases (CIDs) such as rheumatoid arthritis and systemic lupus erythematosus affect outcomes. Purpose: To compare the outcomes of ACLR in cohorts of patients with and without CID. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective query of a regional data set was conducted for all patients who underwent ACLR from 1990 to 2021 for traumatic ACL rupture. All patients with CID were identified and propensity matched to non-CID controls. Baseline characteristics and clinical outcomes were identified through retrospective chart review, and patients were contacted for subjective outcomes. Results: A total of 30 patients with ACLR and a diagnosis of CID were identified. These patients were propensity matched to 120 non-CID controls. Baseline demographic and surgical characteristics demonstrated no statistical differences. Follow-up duration was similar between the CID and non-CID groups (mean, 14.6 vs 14.2 years; P = .868). The CID cohort had a higher arthrofibrosis rate (16.7% vs 4.3%; P = .031), higher osteoarthritis rate (33.3% vs 16.7%; P = .041), higher total knee arthroplasty (TKA) rate (16.7% vs 3.3%; P = .016), and earlier time to TKA (14.7 vs 23.5 years; P = .032). Knee range of motion, infection rate, retear rate, time to retear, and time to osteoarthritis were not statistically different between the cohorts. The CID cohort had higher visual analog scale pain scores (mean, 2.00 vs 1.20; P = .043) but slightly higher satisfaction (mean, 3.92 vs 3.39; P = .043). There were no differences in preinjury Tegner, postoperative Tegner, change in Tegner, or IKDC score. In a univariate Cox regression model, the CID cohort had a retear hazard ratio of 1.43 (95% CI, 0.46-4.51; P = .537). Kaplan-Meier survival revealed no significant differences in retear-free survival between the CID and non-CID cohorts at 25 years (85.7% vs 87.3%; P = .53). The CID cohort had a TKA hazard ratio of 3.94 (95% CI, 1.05-14.8; P = .042). Kaplan-Meier survival demonstrated significantly decreased TKA-free survival at 25 years in the CID cohort (64.9% vs 91.2%; P = .029). Conclusion: CID increases the incidence of arthrofibrosis, osteoarthritis, and TKA in those undergoing ACLR. Patients with CID also undergo TKA significantly sooner than non-CID counterparts. Notably, the majority of patient-reported outcome measures are no worse in patients who have a CID diagnosis. Thus, ACLR constructs themselves may not necessarily fare worse in patients with CID. Nonetheless, these patients need to be cautiously counseled on the clinical outlook after their ACLR.