Abstract: The incidence of meniscus tears and ACL tears in pediatric patients continues to rise, bringing to question the risk factors associated with these injuries. As meniscus tears are commonly repaired in pediatric populations, the epidemiology of repairable meniscus tears is an important for consideration for surgeons evaluating treatment options. Purpose: To describe meniscal tear patterns in pediatric and adolescent patients who underwent meniscal repair across multiple institutions and surgeons, as well as to evaluate the relationship between age, sex, and body mass index (BMI) and their effect on the prevalence, type, and displacement of repaired pediatric meniscal tears. Study Design: Case series; Level of evidence, 4. Methods: Data within a prospective multicenter cohort registry for quality improvement, Sport Cohort Outcome Registry (SCORE), were reviewed to describe repaired meniscal tear patterns. All consecutive arthroscopic meniscal repairs from participating surgeons in patients aged 〈 19 years were analyzed. Tear pattern, location, and displacement were evaluated by patient age, sex, and BMI. A subanalysis was also performed to investigate whether meniscal tear patterns differed between those occurring in isolation or those occurring with a concomitant anterior cruciate ligament (ACL) injury. Analysis of variance was used to generate a multivariate analysis of specified variables. Sex, age, and BMI results were compared across the cohort. Results: There were 1185 total meniscal repairs evaluated in as many patients, which included 656 (55.4%) male and 529 (44.6%) female patients. Patients underwent surgery at a mean age of 15.3 years (range, 5-19 years), with a mean BMI of 24.9 (range, 12.3-46.42). Of the 1185 patients, 816 (68.9%) had ACL + meniscal repair and 369 (31.1%) had isolated meniscal repair. The male patients underwent more lateral tear repairs than the female patients (54.3% to 40.9%; P 〈 .001) and had a lower incidence of medial tear repair (32.1% vs 41.4%; P 〈 .001). Patients with repaired lateral tears had a mean age of 15.0 years, compared with a mean age of 15.4 years for patients with repaired medial or bilateral tears ( P = .001). Higher BMI was associated with “complex” and “radial” tear repairs of the lateral meniscus ( P 〈 .001) but was variable with regard to medial tear repairs. Conclusion: In pediatric and adolescent populations, the data suggest that the surgical team treating knees with potential meniscal injury should be prepared to encounter more complex meniscal tears, commonly indicated in those with higher BMI, while higher rates of lateral meniscal tears were seen in male and younger patients. Future studies should analyze correlates for meniscal repair survival and outcomes in this pediatric cohort undergoing knee surgery.

Abstract: Solitary osteochondromas, or osteocartilaginous exostoses (OCEs), represent the most common benign bone tumor. Despite frequently causing symptoms about the knee in younger populations, there is minimal previous literature investigating surgical treatment. Methods: We retrospectively reviewed the records of patients 〈 20 years old who had undergone surgical treatment of symptomatic, pathologically confirmed, solitary periarticular knee OCE at a single pediatric center between 2003 and 2016. The clinical course, radiographic and pathological features, and complications were assessed. Prospective outreach was performed to investigate patient-reported functional outcomes. Results: Two hundred and sixty-four patients (58% male, 81% athletes) underwent excision of a solitary OCE about the knee at a mean age (and standard deviation) of 14.3 ± 2.24 years. Fifty-five percent of the procedures were performed by orthopaedic oncologists, 25% were performed by pediatric orthopaedic surgeons, and 20% were performed by pediatric orthopaedic sports medicine surgeons, with no difference in outcomes or complications based on training. Of the 264 lesions, 171 (65%) were pedunculated (versus sessile), 157 (59%) were in the distal part of the femur (versus the proximal part of the tibia or proximal part of the fibula), and 182 (69%) were medial (versus lateral). Postoperatively, 96% of the patients returned to sports at a median of 2.5 months (interquartile range, 1.9 to 4.0 months). Forty-two patients (16%) experienced minor complications not requiring operative intervention. Six patients (2%) experienced major complications (symptoms or disability at 〉 6 months or requiring reoperation), which were more common in patients with sessile osteochondromas (p = 0.01), younger age (p = 0.01), and distal femoral lesions as compared with proximal tibial lesions (p = 0.003). Lesion recurrence was identified in 3 patients (1.1%). Overall, the median Pediatric International Knee Documentation Committee (Pedi-IKDC) and mean Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS) scores were 97 (interquartile range, 93 to 99) and 16.7 ± 8.15, respectively, at a median duration of follow-up of 5.8 years. Conclusions: In our large cohort of pediatric patients who underwent excision of solitary knee osteochondromas, most patients were male adolescent athletes. Most commonly, the lesions were pedunculated, were located in the distal part of the femur, and arose from the medial aspect of the knee. Regardless of surgeon training or lesion location, patients demonstrated excellent functional outcomes, with minimal clinically important postoperative complications and recurrences, although patients with sessile lesions and younger age may be at higher risk for complications. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Abstract: There is a paucity of published data regarding the management of osteochondritis dissecans (OCD) lesions of the patellofemoral joint in children and adolescents. Purpose: To evaluate the functional outcomes of surgical management of OCD lesions of the patella and trochlea in children and adolescents. Secondary aims included elucidating predictors for higher functional outcomes and determining complication rates, surgical satisfaction, and ability to return to sports. Study Design: Case series; Level of evidence, 4. Methods: Patients aged 18 years and younger who were surgically treated for OCD of the patella or trochlea were identified. Charts were queried to record patient/lesion data, surgical procedure, results, and complications. Pre- and postoperative imaging was reviewed. Patients were asked to complete a follow-up athletic questionnaire and a Pediatric International Knee Documentation Committee (Pedi-IKDC) questionnaire. Statistical analysis was conducted to look for predictors for reoperation, residual pain, ability to return to sports, and lower Pedi-IKDC scores. Results: A total of 26 children (9 females, 17 males, 3 with bilateral lesions; thus, 29 lesions) were identified. The mean age was 14.7 years (range, 9-18, years), 21 of the 29 knees with lesions (72%) had open physes, and median follow-up was 3.8 years (range, 1-9 years). The most common location was the trochlea (17/29 lesions; 59%). Twenty-two lesions (76%) underwent transarticular drilling (n = 14) or drilling with fixation (n = 8), while 7 underwent excision and marrow stimulation. Four patients (14%) required unplanned reoperation. Internal fixation was predictive of reoperation (odds ratio [OR] = 8.7; 95% CI, 2.8-26.9; P = .04). At final follow-up, 14 knees (48%) were pain free, and 14 (48%) had mild residual pain. Female sex was predictive of residual pain (OR, 9; 95% CI, 2-56; P = .02). Twenty-two patients (85%) returned to sports. Longer duration of preoperative pain negatively affected return to sports (OR, 0.32; 95% CI, 0.05-0.97; P = .04). On postoperative MRI, the lesion appeared completely healed in 2 cases (18%) and partially healed in 9 cases (82%). All 15 survey respondents were satisfied with surgery. The mean Pedi-IKDC score was 82.4 ± 17.8 (range, 40.2-100). Conclusion: Surgical treatment of patellofemoral OCD in children and adolescents produces a high rate of satisfaction and return to sports. Female sex, prolonged duration of symptoms, and internal fixation may be associated with worse outcomes.

Abstract: Patellofemoral instability is a common cause of knee pain and dysfunction in paediatric and adolescent patients. The purpose of the study was to evaluate the frequency of patellar dislocations seen in emergency departments (EDs) and the rates of surgical procedures for patellar instability at paediatric hospitals in the United States between 2004 and 2014. Methods The Pediatric Health Information System database was queried for all paediatric patients who underwent surgery for patellar instability or were seen in the ED for acute patellar dislocation between 2004 and 2014. This was compared with the annual numbers of overall orthopaedic surgical procedures. Results Between 2004 and 2014, there were 3481 patellar instability procedures and 447 285 overall orthopaedic surgical procedures performed at the included institutions, suggesting a rate of 7.8 per 1000 orthopaedic surgeries. An additional 5244 patellar dislocations treated in EDs were identified. Between 2004 and 2014, the number of patellar instability procedures increased 2.1-fold (95% confidence interval (CI) 1.4 to 3.0), while orthopaedic surgical procedures increased 1.7-fold (95% CI 1.3 to 2.0), suggesting a 1.2-fold relative increase in patellar instability procedures, compared with total paediatric orthopaedic surgeries. Conclusion This study shows a significant rise in the rate of acute patellar instability treatment events in paediatric and adolescent patients across the country. Surgery for patellar instability also increased over the study period, though only slightly more than the rate of all paediatric orthopaedic surgical procedures. This may suggest that increasing youth sports participation may be leading to a spectrum of increasing injuries and associated surgeries in children. Level of Evidence IV

Abstract: Participation in organized sports has been increasing over the last several decades for pediatric and adolescent athletes in this country. It is hypothesized that the overall incidence of acute patellar dislocation in this population would increase with more sports participation. Newer surgical techniques for patellar stabilization have also become popular and have been adapted for younger populations. The purpose of the current study was to evaluate the trend in the frequency of patellar dislocations treated at pediatric hospitals in the U.S. versus patients receiving surgical intervention for patellar dislocation. Methods: The Pediatric Health Information System (PHIS) database was queried for all patients 18 years or younger who underwent orthopaedic surgery between 2004 and 2014. A cohort of patients treated surgically for patellar dislocation was compared to a cohort of patients seen in the Emergency Department for management of a patellar dislocation. Data sets from 25 of the 48 pediatric hospitals participating in the PHIS initiative reported data consistently for the study time period and were included in the analysis. The rate of patellar dislocation surgeries per 1,000 pediatric orthopedic surgeries was analyzed for the 11-year period. Linear modeling was used to assess sex-based and overall trends. Results: During the study period, there were 447,285 orthopaedic surgeries at 25 institutions, which included 3,481 patellar dislocation procedures, suggesting a rate of 7.8 per 1,000 orthopaedic surgeries. An additional 5,244 patellar dislocations treated in the emergency room were identified. Over the study period, the number of patellar dislocation procedures increased 2.1-fold (95% CI = 1.4-3.0), while all surgeries increased 1.7-fold (95% CI = 1.3-2.0). There was only a 1.2-fold increase in patellar dislocation procedures relative to total pediatric orthopedic procedures. Emergency Department treatment of patellar dislocation increased 2.8-fold. Females yielded similar trends between operative and Emergency Department treatment of patellar instability (2.2-fold and 2.3 –fold, respectively); while males experienced a higher trend in the need for Emergency Department treatment compared to operative treatment (3.0-fold versus 2.0-fold, respectively). Conclusion / Significance: This study shows a significant rise in the rate of acute patellar instability events in pediatric and adolescent patients across the country. Interestingly, surgery for patellar instability increased by only slightly more than the rate of all pediatric orthopaedic procedures. Further research is needed to evaluate the link between increased acute patellar instability and risk for chronic patellar instability along with the potential need for surgical intervention.

Abstract: The majority of research on medial (MCL) and lateral (LCL) collateral ligament injuries has focused on adults and combined collateral/cruciate injuries. The purpose of this study was to determine characteristics associated with isolated collateral ligament injuries in adolescents, and assess timing for return to sports. Methods: Electronic medical records were queried to identify patients aged below 17 years who sustained a magnetic resonance imaging–confirmed isolated MCL or LCL injury over an 8-year period. Retrospective review then documented patient and injury characteristics and clinical course. General linear modeling was used to analyze risk factors for prolonged return to sports, continued pain or reinjury. Results: Fifty-one knees (33 in males, 65%), mean age 13.8 years (range, 5 to 17), were identified, of which 40 (78%) had MCL injuries. Over half (29, 57%) of knees had an open distal femoral physis including all 5 bony avulsion injuries. Eleven (22%) had LCL injuries of which 3 (6%) had concurrent posterolateral corner injuries. Forty-two (82%) knees had injuries that occurred during sports. Eleven knees (28%) with MCL tears had a simultaneous patellar instability episode. Knee injuries that occurred during sports had 37% shorter recovery time ( P =0.02). Eight knees (16%) experienced a reinjury and 12 (24%) were followed over an extended period of time for various knee issues. Football injuries were more likely to be grade 3 ( P =0.03), and football and soccer accounted for all grade III injuries. The mean return to sports was 2.2 months, with grade III cases returning at 2.4 months, and 95% of cases within 4 months. Conclusions: Isolated collateral ligament injuries are rare in adolescent athletes. MCL injuries, one-quarter of which occurred in conjunction with patellar instability events, were 4 times more common than LCL injuries, one quarter of which have other posterolateral corner structures involved. Grade III injuries represent 20% to 25% of collateral ligament injuries and occurred most commonly in football and soccer. Level of Evidence: Level IV—retrospective case series.

Abstract: Anterior cruciate ligament reconstruction (ACLR) remains one of the most commonly performed orthopaedic surgeries in adolescents and young adults. However, selection of the optimal graft for the individual patient remains controversial, considering multiple graft options, subtle technique differences, and wide-ranging bodies of evidence for each graft option in largely adult populations. However, multiple epidemiologic studies clearly demonstrate adolescents as the most greatly affected age-based sub-population, with the highest rates of re-tear and global morbidity, due to psychological and physical effects of long absences from athletic activity. Nevertheless, methodologically rigorous comparative studies specific to the adolescent athlete are largely absent from the literature. The purpose of the current study is to therefore investigate the outcomes of ACLR in adolescents receiving either patellar tendon/bone-tendon-bone (BTB) autograft (ACLR-BTB) or hamstring tendon autograft (ACLR-HS), using retrospective propensity score matching techniques to generate comparable cohorts. Methods: The study was designed as a retrospective chart review, with collection of cross-sectional data from a single pediatric tertiary care center over a thirteen year period (2003-2015). An initial cohort of patients, aged 13-19 years at time of primary ACLR-BTB or primary ACLR-HS by one of 5 surgeons, was identified through a comprehensive electronic medical record database query. Propensity score matching of ACLR-BTB and ACLR-HS subjects through a logistic regression model, with caliper restriction of 0.1 standard deviations, was then applied, based upon specific baseline characteristics that are frequently used by some surgeons to guide graft selection: age, sex, and body mass index (BMI). The resultant cohort of patients obtained a 1:2 (ACLR-BTB: ACLR-HS, 83 patients:186 patients) match. A chart review was performed to identify patient demographics, surgical data, and post-operative outcomes including graft rupture/re-tear and length of clinical follow-up. Patients were additionally contacted to obtain longer term sport participation and re-injury data that may have been investigated or addressed at outside institutions, as well as to obtain functional outcomes using region-specific questionnaires (Pedi-IKDC and HSS-Pedi FABS), which are validated for both this younger population and adult populations. Due to previous literature-based reports on greater anterior knee pain following ACLR-BTB, compared to ACL-HS, scores from the questions specific to knee pain or kneeling pain were extracted from the Pedi-IKDC results and analyzed to assess the potential influence of anterior knee pain on overall scores within this adolescent population. Results: At time of ACLR, the mean age and BMI of the matched ACLR-BTB patients were 17.1 years (sd: +/-1.14 years) and 25.8 (sd: +/-5.04), compared to 16.9 years (sd: +/- 1.38, p: 0.18) and 24.9 (sd: +/- 5.01, p: 0.18) for matched ACLR-HS patients, with similar male preponderance (ACLR-BTB: 77%, ACLR-HS: 72%, p: 0.47) and mean length of follow-up (ACLR-BTB: 42.9 months; ACLR-HS: 43.3 months). While mean Pedi-IKDC scores were slightly higher in the ACLR-BTB group (88.8; sd: +/-10.2, range: 56.5-100) than the ACLR-HS group (85.2; sd: +/- 16.1, range: 23.9-100), this difference was not statistically different (p: 0.50). When scores on questions regarding knee pain and kneeling difficulty were analyzed, no differences were seen between graft cohorts (ACLR-BTB: median knee pain score: 4, ACLR-HS: 4 p: 0.73; ACLR-BTB median kneeling difficulty score: 4, ACLR-HS: 4, p: 0.21). Activity level, based on the HSS-Pedi FABS score, was also similar (ACLR-BTB: 16, range: 3-29 vs. ACLR-HS: 17, range: 0-30; p: 0.96). Rates of ACL graft re-tear were not significantly different between groups, both when calculated based all possible follow-up methods (ACLR-BTB: 11%, ACLR-HS: 11%, p: 0.91), or when those patients responding to long-term follow up questionnaires were isolated (ACLR-BTB: 15%, ACLR-HS: 16%, p: 0.85). Conclusion/Significance: Despite previous studies, including large, multi-country registry-based analyses, demonstrating lower re-tear rates following ACLR-BTB than ACLR-HS, the current study, focused exclusively on adolescent cohorts matched for age, sex, and BMI, showed no difference in graft re-tear rates between the two cohorts at medium-term follow-up. Moreover, activity scores and functional knee outcome scores appear to be equivalent between these younger graft-based populations. In contrast to previous studies associating BTB autograft with greater long term anterior knee pain, adolescents appear to have equal degrees of knee pain or kneeling pain, regardless of graft choice, which may stem from greater healing and biologic remodeling capacity at graft harvest sites than adults or more modern techniques of patellar bone grafting and paratenon closure. Given the consistently high adolescent ACL re-tear rates in this and other studies, continued focus on ACL prevention programs and optimizing the timing and safety of return to play remains critical.

Abstract: Achilles tendon tears are rare in adolescents and young adults, and management of these injuries remains controversial. Hypothesis/Purpose: To describe long-term limitations and physical activity levels following full or partial Achilles tears in adolescents and young adults, and report rates of surgical management, complications, re-tears, and time to return to sports (RTS). Methods: We conducted a descriptive study of young patients (8-22 years old) who were treated for a partial or full Achilles tear at two pediatric hospitals between 2004-2018. Demographic, imaging, and treatment data were retrospectively collected. Patient reported outcomes were obtained including the Achilles Tendon Total Rupture Score (ATRS), Foot and Ankle Outcomes Score (FAOS), Tegner Activity Scale (TAS), and separate questions about reinjury and return to sport. Results: Of the 41 eligible patients with Achilles injuries, 25 (61%; mean age 18.9 years; 40% male) had a minimum one year of follow-up data and were further analyzed. Twenty-three patients (92%) underwent surgical repair. Twenty patients (80%) returned questionnaires at a median 6.3 years (IQR, 3.4 to 9.7 years), while the other 5 patients were followed for a median of 1.8 years (IQR, 1.1 to 2.5 years). Twenty-two (88%) injuries were full tears, 53% (10/19) with reported location occurring mid-tendon. Median ATRS score was 96 (IQR, 82-100) and median TAS score was 6 (4-8). Median FAOS scores were excellent for symptoms (91), pain (100), ADL (100), and sports (98), and were good for QOL (88). The 6-month RTS probability was 47% (95% CI, 19-66%) and at 12 months was 95% (65-99%). The median time to RTS for partial tears was 5.6 months vs. 6.6 months for full tears (p=0.05). One surgical patient (4%) had a retear which required revision repair while 2 others needed additional surgery (1 - arthroscopy for ankle impingement, 1 - surgery for haglund’s deformity). In addition to the 3 surgical patients requiring re-operation, 8 patients experienced other complications (11/25 total complications, 44%), which included minor wound/scar complications (4), scar formation necessitating hydrodissection (1), Achilles tendonitis (2), and persistent pain following conservative treatment leading to surgical repair (1). Females were more likely to experience a complication (9/15, 60%) compared to males (2/10, 20%), but this difference was not statistically significant (p=0.10). Conclusion: Adolescents and young adults surgically treated for an Achilles injury reported satisfactory long-term outcomes.