Mininder S. Kocher’s research while affiliated with Boston University and other places

Background There are limited evidence-based guidelines to predict which osteochondritis dissecans (OCD) lesions will heal with nonoperative treatment. Purpose To train a set of classification algorithms to predict nonoperative OCD healing while identifying new clinically meaningful predictors. Study Design Case-control study; Level of evidence, 3. Methods Patients with OCD of the knee with open physes undergoing nonoperative management were prospectively queried from the Research on OCD of the Knee (ROCK) cohort ( https://kneeocd.org ) in April 2022. Patients were included if they met the study criteria for nonoperative treatment success or failure. Nonoperative treatment success was defined as complete healing on magnetic resonance imaging (MRI) and total return to sports participation. Failure was defined as the crossover from nonoperative management to surgery at any point at or beyond the 3-month follow-up. If a patient did not meet one of these criteria, they were not included. Normalized lesion size, lesion location, patient characteristics, and symptoms were used as clinically relevant predictors. Results A total of 64 patients were included, of whom 24 (37.5%) patients successfully healed with nonoperative management. Multivariate logistic regression revealed that a 1% increase in normalized lesion width was associated with an increase in the likelihood of nonoperative failure (odds ratio [OR], 1.41 [95% CI, 1.17-1.81]; P < .01). By contrast, lesions in the posterior sagittal zone (OR, 0.08 [95% CI, 0.009-0.43]; P < .01) or the medial-most coronal zone (for lesions of the medial femoral) and lateral-most coronal zone (for lesions of the lateral femoral condyle) on MRI (OR, 0.05 [95% CI, 0.004-0.44]; P < .01) were associated with a decrease in the likelihood of nonoperative treatment failure. Support vector machines had a cross-validated area under the receiver operating characteristic curve of 0.89 and a classification accuracy of 83.3%. Conclusion Lesion location in the posterior aspect of the condyle on sagittal MRI and lesion location in the medial-most or lateral-most locations on coronal MRI were identified as statistically significant predictors of increased nonoperative treatment success on multivariate analysis. Machine learning models can predict which OCD lesions will heal with nonoperative management with superior accuracy compared with previously published models.

Background Osteochondritis dissecans (OCD) of the knee is a focal idiopathic alteration of subchondral bone and/or its precursor with risk for instability and disruption of adjacent cartilage. Treatment options focused on preventing premature osteoarthritis vary depending on multiple patient and lesion characteristics, including lesion mobility. Purpose To differentiate lesion mobility before arthroscopy using a multivariable model that includes patient demographic characteristics and physical examination findings. Study Design Cohort study (Diagnosis); Level of evidence, 2. Methods Demographic, preoperative physical examination, and radiographic data were collected from a multicenter national prospective cohort of patients with OCD of the knee. Inclusion criteria included patients <19 years of age and patients with arthroscopically confirmed mobility status based on the Research on Osteochondritis Dissecans of the Knee arthroscopy classification. Multivariable logistic regression analysis using stepwise model selection was used to determine factors associated with the likelihood of a mobile versus an immobile lesion. A 75% partition of the data was used for model training, and 25% was used as a validation cohort. Quantitative model fit statistics were computed using the holdout data, including sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC), along with the corresponding 95% CI. Results A total of 407 patients in the prospective cohort met inclusion criteria, and 62% were male. The mean ± SD age was 13.7 ± 2.2 years, height 161.8 ± 5.3 cm, and weight 59.2 ± 42.2 kg. Arthroscopic evaluation yielded 235 immobile and 172 mobile lesions. Multivariable analysis determined that the best model to predict lesion mobility included chronologic age ≥14 years ( P < .001), effusion on physical examination ( P < .001), and any loss of range of motion on physical examination ( P = .07), while controlling for male sex ( P = .38) and weight >54.4 kg ( P = .12). In the 25% holdout validation sample (n = 102), a sensitivity of 83%, a specificity of 82%, and an AUC of 0.89 (95% CI, 0.82-0.95) were achieved with these predictive factors. Conclusion Age, effusion, and loss of motion can predict knee OCD lesion mobility at the time of arthroscopy. Education about lesion mobility can help with surgical planning and patient and family counseling.

Objectives Ischial tuberosity avulsion fractures are relatively rare injuries that typically occur in young athletes during activity. Some of these patients may experience significant morbidity, often through chronic pain and changes in sports participation. The influence of fragment displacement on optimal treatment and proper return to sport protocol has not been well investigated. This study sought to evaluate the relationship between displacement and both choice of treatment and time to return to sport. Methods Retrospective analysis of ischial tuberosity avulsion fractures in pediatric patients between 2010-2021 at Boston Children’s Hospital was completed. Information regarding demographics, treatment, and recovery were extracted from individual patient charts. Plain radiographs and magnetic resonance imaging (MRI) were analyzed in order to measure fragment displacement at the ischial apophysis. Treatment protocol, return to sport (RTS) time, and complications were analyzed. Results Eighty-eight patients with a diagnosis of an ischial tuberosity avulsion fracture were identified. Of these, 64 (73%) were treated non-operatively, 8 (9%) were treated acute operatively (within 6 weeks), and 16 (18%) were treated chronic operatively (>6 weeks). Imaging for measurement of fragment displacement was available for 86 (98%) of patients. The median displacement was 0.2cm for the non-operative group, 2.2cm for the acute operative group, and 1.5 for the chronic operative group. Of the 86 patients with available imaging, 67 (78%) had a RTS time. The median RTS was 3.6 months in the non-operative group, 5.5 months in the acute operative group, and 13.3 months in the chronic operative group. Conclusions In this retrospective cohort study, nearly all fractures with displacement >= 1.0cm were surgically treated, either acutely or at a delayed time point. All patients that underwent acute operation had displacement > 1.0cm, while 87% of those undergoing delayed operation had displacements > 1.0cm. Those treated non-operatively returned to sport about 1 month earlier than those undergoing acute operation, and several months prior to those who underwent delayed surgical intervention. This data suggests that patients with displacement less than 1.0cm may be successfully treated through non-operative treatment and those with displacement greater than this should undergo operative treatment in the acute period to optimize outcome and return to sport.

Objectives Snowboarding is a high energy sport associated with traumatic musculoskeletal injury. Although the pediatric population constitutes most snowboarding injuries, no study has investigated this cohort in further detail. The purpose of this study is to analyze underlying etiologies, diagnoses, and injury trends of pediatric snowboarding injuries presenting to United States emergency departments. Methods Data from the National Electronic Injury Surveillance System (NEISS) were analyzed for pediatric snowboarding injuries (≤18 years old) from January 1, 2012 to December 31, 2022. Data were collected for mechanism of injury, diagnosis, location of injury, and disposition. National estimates (NE) were calculated using the statistical sample weight of the corresponding hospital assigned by the NEISS. Linear regressions were used to analyze injury trends over time. Results In total, 3,036 (NE=120,140) pediatric snowboarding injuries were included in this study. Average age was 14.0 ± 2.7 years. The most common mechanism of injury was impact with the ground (NE=97,120, 80.8%). The most common diagnoses were fractures (NE=48,886, 40.7%), strains/sprains (NE=22,948, 19.1%), and concussions (NE=12,553, 10.4%). Most common fractures occurred at the wrist (NE=18,122, 37.1%), lower arm (NE=12,348, 25.3%), and shoulder (NE=9,073, 18.6%). Overall, 96.1% injuries were treated without admission. There were decreases of 1,051 injuries (p<0.01), 299 fractures (p=0.04), 298 strains/sprains (p<0.001), and 143 concussions (p<0.01) per year during the study period. Mechanisms of injury demonstrated decreasing annual trends of 784 impact with ground injuries per year (p<0.01), 161 not specified injuries per year (p<0.01), and 42 impact with inanimate object injuries per year (p=0.03). Conclusions There was a large decline in pediatric snowboarding injuries over the last decade. Given the small proportion requiring hospital admission, the decline may reflect increasing on-site management of less-severe snowboarding injuries. These findings also highlight the importance of protective equipment considering the large proportion of injuries secondary to impact with the ground.

Background Readiness for return to sports involves both physical and psychological aspects of recovery; however, the relationship between psychological and physical variables after anterior cruciate ligament (ACL) reconstruction (ACLR) is poorly understood. Hypothesis ACLR patients with a higher psychological readiness would demonstrate better functional testing results at 6 months. Study Design Cross-sectional study; Level of evidence, 3. Methods Participants were evaluated at 6 months after ACLR with various patient-reported outcome metrics: Hospital for Special Surgery Pediatric Functional Activity Brief Scale, pediatric or adult International Knee Documentation Committee Questionnaire (IKDC), Patient-Reported Outcomes Measurement Information System (PROMIS) - Psychological Stress Experience and ACL - Return to Sport After Injury (ACL-RSI) scale. Functional testing included quadriceps, hamstrings, and gluteal strength testing; Y-balance test; single-leg single hop, crossover hop, and triple hop tests; and timed 6-m hop test. Pearson correlation coefficient and multivariable regression were used to determine associations between the limb symmetry index (LSI) on functional testing and patient-reported outcomes. Those with LSI deficits <20% (better performance) were compared with those with deficits >20% (worse performance). Results A total of 229 participants (89 male, 140 female) with a median age of 17 years (range, 10.3-30.6 years) were enrolled. IKDC had a moderate negative correlation with PROMIS - Psychological Stress Experience ( r = -0.39; 95% CI = -0.49, -0.27; P < .001) and a moderate positive correlation with ACL-RSI ( r = 0.55; 95% CI = 0.46, 0.64; P < .001). A total of 151 patients completed functional testing. ACL-RSI demonstrated a positive correlation with single-hop LSI ( r = 0.21; 95% CI = 0.05, 0.35; P = .01) and timed 6-m hop ( r = 0.28; 95% CI, 0.42; P = .001). When adjusting for sex, age, and graft type, patients who had <20% deficit on the single-hop test scored 16.6 points higher on ACL-RSI ( P = .001), and those with <20% deficit on crossover hop testing scored a mean 13.9 points higher on ACL-RSI ( P = .04) Conclusion Higher psychological readiness for return to sport was associated with better performance and greater symmetry on hop testing 6 months after ACLR, suggesting a potential link between physical and psychological recovery.

Background Anterior cruciate ligament (ACL) injury in youth can lead to expensive treatment, lengthy rehabilitation, and long-term impairment. Injuries to the ACL are more common in adolescents who participate in organized sports. Purpose To examine whether there is an association between age, physical activity patterns, pubertal timing (Tanner stage), or body mass index (obesity/overweight status) and the risk of developing an ACL injury in youth. Study Design Cohort study; Level of evidence, 2. Methods Data from the Growing Up Today Study (GUTS), a prospective cohort study of youth throughout the United States, were used in this study. From 1996 to 2003, questionnaires were sent to GUTS participants every 12 to 18 months to assess a variety of self-reported factors; in a related 2004 questionnaire, ACL tears and other diagnoses among the participants were reported. Cox proportional hazard models were run to determine the sex-specific association of activity patterns and pubertal timing with risk of developing an ACL tear. Results A total of 4519 boys and 5622 girls (age: 9-15 years) were included, with 2.4% and 2.0% sustaining an ACL injury, respectively. Age was found to be a significant risk factor for ACL injury in both sexes (male: hazard ratio [HR] = 1.30 [95% CI, 1.14-1.48]; female: HR = 1.23 [95% CI, 1.10-1.38]). Mean hours per week engaged in vigorous activity was also predictive of a higher risk of ACL injury (male: HR = 1.04 [95% CI, 1.01-1.08]; female: HR = 1.10 [95% CI, 1.07-1.14]). The sports that were the most predictive of injury were running, basketball, soccer, and cheerleading/gymnastics in girls and running, football, and karate/martial arts in boys. Additionally, in boys, overweight/obese status was found to be a significant predictor of ACL injury (HR = 2.61 [95% CI, 1.60-4.26]). Furthermore, among 9- to 13-year-old girls, advanced Tanner stage was a strong predictor of injury risk (HR = 2.43 [95% CI, 1.10-5.36]). Conclusion Age, time engaged in vigorous activity, overweight/obese status, and advanced Tanner stage were associated with an increased risk of ACL injury in young adults and adolescents. Further research with follow-up data will help complement this study and continue to highlight the risk factors associated with ACL reconstruction in adolescents and young adults.

With the pronounced ongoing growth of global youth sports, opportunities for and participation of youth athletes on the world sports stage, including the Olympic Games, are expected to escalate. Yet, adolescence is a vulnerable period of development and inherently dynamic, with non-linear and asynchronous progression of physical, physiological, psychological and social attributes. These non-concurrent changes within and between individuals are accompanied by irregular and unpredictable threats and impediments. Likewise, the evident age-based criteria and conventional path for those youth athletes deemed eligible candidates for the Olympic Games are not well or consistently defined. Furthermore, the unstructured and largely varying policies and practices across the sporting International Federations specific to youth participation underscore the need to establish a contemporary universal paradigm that would enable elite youth athletes to navigate an individualised healthy pathway to personal, athletic and sport success. First, we reviewed and summarised key challenges facing elite youth athletes and the relevant evidence fundamental to facilitating and supporting central aspects of health and well-being, while empowering safe, sustainable and positive engagement during athletic and personal advancement and competition. Second, we developed and present a modern elite youth athlete model that emphasises a child-centred, practical framework with corresponding guidelines and recommendations to protect health and well-being while safely and favourably managing international sport competition. Our proposed evidence-informed paradigm will enable and support individualised pathways for healthy, well-rounded and sustainable positive engagement while achieving sport success for youth contending or aiming to compete at world-class international sporting events.

Background Social determinants of health (SDOHs) affect health outcomes outside the hospital, and understanding them can enhance postoperative outcomes in orthopaedic surgery patients. This study aimed to describe the prevalence of randomized controlled trials (RCTs) in pediatric orthopaedic journals reporting on the SDOHs of their patient cohorts. We hypothesize that many SDOHs will be underreported in RCTs investigating pediatric orthopaedic surgery. Methods Utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, the authors queried the PubMed database to examine SDOHs from 2 pediatric orthopaedic journals: Journal of Pediatric Orthopaedics and Journal of Pediatric Orthopaedics: Part B. The inclusion criteria incorporated RCTs published between 2005 and April 2024. The exclusion criteria included any articles that were not RCTs published in this period. Results One hundred thirteen articles met the search criteria, with 31 excluded because they did not fall from 2005 to 2024. Eighty-two were published from 2005 to 2024, but 6 RCTs were excluded, as 3 were non-RCTs, and 3 examined cadavers. Seventy-six RCTs were included for analysis, with 65 articles from the Journal of Pediatric Orthopaedics and 11 articles from the Journal of Pediatric Orthopaedics: Part B . Articles originated from 17 countries, with the United States producing 61.8% (47) of the included studies. Of all 76 included studies, 96.1% (73) reported age, 88.2% (67) reported sex/gender, 30.3% (23) reported BMI, 21.1% (16) reported race/ethnicity, 5.3% (4) reported educational level, 2.6% (2) reported stress, and 2.6% (2) reported insurance. Smoking status, socioeconomic status, income levels, and employment status were each reported by only 1 study. Conclusions The RCTs examining pediatric orthopaedic surgery tend to scarcely report SDOHs. Future RCTs should expand beyond demographic characteristics such as age, race/ethnicity, sex/gender, and BMI and incorporate other relevant SDOHs. This will allow us to develop a more comprehensive understanding of health outcomes in the pediatric orthopaedic population. Level of Evidence I; Therapeutic Studies.