Fixation Strategy Does Not Affect Risk of Growth Disturbance After Surgical Treatment of Pediatric Tibial Spine Fracture.

Purpose: To characterize growth abnormalities after surgical treatment of tibial spine fractures and to investigate risk factors for these abnormalities. Methods: A retrospective analysis of children who underwent treatment of tibial spine fractures between January 2000 and January 2019 was performed, drawing from a multicenter cohort among 10 tertiary care children's hospitals. The entire cohort of surgically treated tibial spine fractures was analyzed for incidence and risk factors of growth disturbance. The cohort was stratified into those who were younger than the age of 13 years at the time of treatment in order to evaluate the risk of growth disturbance in those with substantial growth remaining. Patients with growth disturbance in this cohort were further analyzed based on age, sex, surgical repair technique, implant type, and preoperative radiographic measurements with χ2, t-tests, and multivariate logistic regression. Results: Nine patients of 645 (1.4%) were found to have growth disturbance, all of whom were younger than 13 years old. Patients who developed growth disturbance were younger than those without (9.7 years vs 11.9 years, P = .019.) There was no association with demographic factors, fracture characteristics, surgical technique, hardware type, or anatomic placement (i.e., transphyseal vs physeal-sparing fixation) and growth disturbance. Conclusions: In this study, we found an overall low incidence of growth disturbance after surgical treatment of tibial spine fractures. There was no association with surgical technique and risk of growth disturbance. Level of Evidence: Level III, retrospective comparative study.

What Are the Causes and Consequences of Delayed Surgery for Pediatric Tibial Spine Fractures? A Multicenter Study.

Background: The uncommon nature of tibial spine fractures (TSFs) may result in delayed diagnosis and treatment. The outcomes of delayed surgery are unknown. Purpose: To evaluate risk factors for, and outcomes of, delayed surgical treatment of pediatric TSFs. Study Design: Cohort study; Level of evidence, 3. Methods: The authors performed a retrospective cohort study of TSFs treated surgically at 10 institutions between 2000 and 2019. Patient characteristics and preoperative data were collected, as were intraoperative information and postoperative complications. Surgery ≥21 days after injury was considered delayed based on visualized trends in the data. Univariate analysis was followed by purposeful entry multivariate regression to adjust for confounders. Results: A total of 368 patients (mean age, 11.7 ± 2.9 years) were included, 21.2% of whom underwent surgery ≥21 days after injury. Patients who experienced delayed surgery had 3.8 times higher odds of being diagnosed with a TSF at ≥1 weeks after injury (95% CI, 1.1-14.3; P = .04), 2.1 times higher odds of having seen multiple clinicians before the treating surgeon (95% CI, 1.1-4.1; P = .03), 5.8 times higher odds of having magnetic resonance imaging (MRI) ≥1 weeks after injury (95% CI, 1.6-20.8; P < .007), and were 2.2 times more likely to have public insurance (95% CI, 1.3-3.9; P = .005). Meniscal injuries were encountered intraoperatively in 42.3% of patients with delayed surgery versus 21.0% of patients treated without delay (P < .001), resulting in 2.8 times higher odds in multivariate analysis (95% CI, 1.6-5.0; P < .001). Delayed surgery was also a risk factor for procedure duration >2.5 hours (odds ratio, 3.3; 95% CI, 1.4-7.9; P = .006). Patients who experienced delayed surgery and also had an operation >2.5 hours had 3.7 times higher odds of developing arthrofibrosis (95% CI, 1.1-12.5; P = .03). Conclusion: Patients who underwent delayed surgery for TSFs were found to have a higher rate of concomitant meniscal injury, longer procedure duration, and more postoperative arthrofibrosis when the surgery length was >2.5 hours. Those who experienced delays in diagnosis or MRI, saw multiple clinicians, and had public insurance were more likely to have a delay to surgery.

Does Insurance Status Affect Treatment of Children With Tibial Spine Fractures?

BACKGROUND: Previous studies have reported disparities in orthopaedic care resulting from demographic factors, including insurance status. However, the effect of insurance on pediatric tibial spine fractures (TSFs), an uncommon but significant injury, is unknown. PURPOSE: To assess the effect of insurance status on the evaluation and treatment of TSFs in children and adolescents. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: We performed a retrospective cohort study of TSFs treated at 10 institutions between 2000 and 2019. Demographic data were collected, as was information regarding pre-, intra-, and postoperative treatment, with attention to delays in management and differences in care. Surgical and nonsurgical fractures were included, but a separate analysis of surgical patients was performed. Univariate analysis was followed by purposeful entry multivariate regression to adjust for confounding factors. RESULTS: Data were collected on 434 patients (mean ± SD age, 11.7 ± 3.0 years) of which 61.1% had private (commercial) insurance. Magnetic resonance imaging (MRI) was obtained at similar rates for children with public and private insurance (41.4% vs 41.9%, respectively; P≥ .999). However, multivariate analysis revealed that those with MRI performed ≥21 days after injury were 5.3 times more likely to have public insurance (95% CI, 1.3-21.7; P = .02). Of the 434 patients included, 365 required surgery. Similar to the overall cohort, those in the surgical subgroup with MRI ≥21 days from injury were 4.8 times more likely to have public insurance (95% CI, 1.2-19.6; P = .03). Children who underwent surgery ≥21 days after injury were 2.5 times more likely to have public insurance (95% CI, 1.1-6.1; P = .04). However, there were no differences in the nature of the surgery or findings at surgery. Those who were publicly insured were 4.1 times more likely to be immobilized in a cast rather than a brace postoperatively (95% CI, 2.3-7.4; P < .001). CONCLUSION: Children with public insurance and a TSF were more likely to experience delays with MRI and surgical treatment than those with private insurance. However, there were no differences in the nature of the surgery or findings at surgery. Additionally, patients with public insurance were more likely to undergo postoperative casting rather than bracing.

A Novel Shorthand Approach to Knee Bone Age Using MRI: A Validation and Reliability Study.

BACKGROUND: Bone-age determination remains a difficult process. An atlas for bone age has been created from knee-ossification patterns on magnetic resonance imaging (MRI), thereby avoiding the need for radiographs and associated costs, radiation exposure, and clinical inefficiency. Shorthand methods for bone age can be less time-consuming and require less extensive training as compared with conventional methods. PURPOSE: To create and validate a novel shorthand algorithm for bone age based on knee MRIs that could correlate with conventional hand bone age and demonstrate reliability across medical trainees. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Included in this study were adolescent patients who underwent both knee MRI and hand bone age radiographs within 90 days between 2009 and 2018. A stepwise algorithm for predicting bone age using knee MRI was developed separately for male and female patients, and 7 raters at varying levels of training used the algorithm to determine the bone age for each MRI. The shorthand algorithm was validated using Spearman rho (r S) to correlate each rater's predicted MRI bone age with the recorded Greulich and Pyle (G&P) hand bone age. Interrater and intrarater reliability were also calculated using intraclass correlation coefficients (ICCs). RESULTS: A total of 38 patients (44.7% female) underwent imaging at a mean age of 12.8 years (range, 9.3-15.7 years). Shorthand knee MRI bone age scores were strongly correlated with G&P hand bone age (r S = 0.83; P < .001). The shorthand algorithm was a valid predictor of G&P hand bone age regardless of level of training, as medical students (r S = 0.75), residents (r S = 0.81), and attending physicians (r S = 0.84) performed similarly. The interrater reliability of our shorthand algorithm was 0.81 (95% CI, 0.73-0.88), indicating good to excellent interobserver agreement. Respondents also demonstrated consistency, with 6 of 7 raters demonstrating excellent intrarater reliability (median ICC, 0.86 [range, 0.68-0.96]). CONCLUSION: This shorthand algorithm is a consistent, reliable, and valid way to determine skeletal maturity using knee MRI in patients aged 9 to 16 years and can be utilized across different levels of orthopaedic and radiographic expertise. This method is readily applicable in a clinical setting and may reduce the need for routine hand bone age radiographs.

Anterior Cruciate Ligament Tear Following Operative Treatment of Pediatric Tibial Eminence Fractures in a Multicenter Cohort.

BACKGROUND: Postoperative ipsilateral anterior cruciate ligament (ACL) tears after tibial eminence fracture fixation has been previously noted in the literature. This study aims to describe the prevalence of and risk factors for postoperative ACL tears in a cohort of patients operatively treated for tibial eminence fracture. METHODS: A retrospective review of children undergoing treatment of a tibial eminence fracture at 10 tertiary care children's hospitals was performed. The primary outcome of interest was subsequent ACL rupture. Incidence of ACL tear was recorded for the entire cohort. Patients who sustained a postoperative ACL tear were compared with those without ACL tear and analyzed for demographics and risk factors. A subgroup analysis was performed on patients with a minimum of 2-year follow-up data or those who had met the primary outcome (ACL tear) before 2 years. RESULTS: A total of 385 pediatric patients were reviewed. 2.6% of the cohort experienced a subsequent ACL tear. The median follow-up time was 6.5 months (SD=6.4 mo). Subsequent ACL tears occurred at a median of 10.2 months (SD=19.5 mo) postoperatively. There was a statistically significant association with higher grade tibial spine fractures (Myers and McKeever type III and IV) and subsequent ACL tear (P=0.01). Patients with a subsequent ACL tear were older on average (13.5 vs. 12.2 y old), however, this difference was not statistically significant (P=0.08). Subgroup analysis of 46 patients who had a 2-year follow-up or sustained an ACL tear before 2 years showed a 21.7% incidence of a subsequent ACL tear. There was a statistically significant association with higher grade tibial spine fractures (Myers and McKeever type III and IV) and subsequent ACL rupture (P=0.006) in this subgroup. Postoperative ACL tears occurred in patients who were older at the time that they sustained their original tibial eminence fracture (13.4 vs. 11.3 y old, P=0.035). CONCLUSIONS: Ipsilateral ACL tears following operatively treated pediatric tibial eminence fractures in a large multicenter cohort occurred at a rate of 2.6%. However, in those with at least 2 years of follow-up, the incidence was 21.7%. Subsequent ACL tear was more likely in those with completely displaced (type III or IV) tibial eminence fractures and older patients. LEVEL OF EVIDENCE: Level III-retrospective cohort study.

A Comparison of Nonoperative and Operative Treatment of Type 2 Tibial Spine Fractures.

BACKGROUND: Tibial spine fractures (TSFs) are typically treated nonoperatively when nondisplaced and operatively when completely displaced. However, it is unclear whether displaced but hinged (type 2) TSFs should be treated operatively or nonoperatively. PURPOSE: To compare operative versus nonoperative treatment of type 2 TSFs in terms of overall complication rate, ligamentous laxity, knee range of motion, and rate of subsequent operation. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: We reviewed 164 type 2 TSFs in patients aged 6 to 16 years treated between January 1, 2000, and January 31, 2019. Excluded were patients with previous TSFs, anterior cruciate ligament (ACL) injury, femoral or tibial fractures, or grade 2 or 3 injury of the collateral ligaments or posterior cruciate ligament. Patients were placed according to treatment into the operative group (n = 123) or nonoperative group (n = 41). The only patient characteristic that differed between groups was body mass index (22 [nonoperative] vs 20 [operative]; P = .02). Duration of follow-up was longer in the operative versus the nonoperative group (11 vs 6.9 months). At final follow-up, 74% of all patients had recorded laxity examinations. RESULTS: At final follow-up, the nonoperative group had more ACL laxity than did the operative group (P < .01). Groups did not differ significantly in overall complication rate, reoperation rate, or total range of motion (all, P > .05). The nonoperative group had a higher rate of subsequent new TSFs and ACL injuries requiring surgery (4.9%) when compared with the operative group (0%; P = .01). The operative group had a higher rate of arthrofibrosis (8.9%) than did the nonoperative group (0%; P = .047). Reoperation was most common for hardware removal (14%), lysis of adhesions (6.5%), and manipulation under anesthesia (6.5%). CONCLUSION: Although complication rates were similar between nonoperatively and operatively treated type 2 TSFs, patients treated nonoperatively had higher rates of residual laxity and subsequent tibial spine and ACL surgery, whereas patients treated operatively had a higher rate of arthrofibrosis. These findings should be considered when treating patients with type 2 TSF.

Complications and Controversies in the Management of 5 Common Pediatric Sports Injuries.

Growing participation in sports among children, along with increasingly intense training regimens, has contributed to an increasing rate of sports-related injuries. Despite the similarities to adult sports injuries, pediatric patients have distinctive injury patterns because of the growing physis and therefore necessitate unique treatment algorithms. Caring for these injured children requires in-depth knowledge of not only pediatric injury patterns, but also the scope of age-specific treatments, the associated complications, and the controversies. When treating motivated pediatric athletes, one must be able to strike a delicate balance between patients' eagerness to return to sport and the need to ensure their long-term health and function. Knowledge of controversies and complications will help both patients and physicians make informed decisions about how best to restore pediatric athletes back to health.

Four Risk Factors for Arthrofibrosis in Tibial Spine Fractures: A National 10-Site Multicenter Study.

BACKGROUND: Tibial spine fractures (TSFs) are relatively rare pediatric injuries. Postoperative arthrofibrosis remains the most common complication, with few studies having examined factors associated with its development. PURPOSE: To identify risk factors for arthrofibrosis and required MUA or lysis of adhesions in the largest known cohort of patients with TSFs. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: This was a multicenter study of 249 patients ≤18 years old who had a TSF between January 2000 and February 2019. Patients were separated into cohorts based on whether they developed arthrofibrosis, defined as a 10° deficit in extension and/or 25° deficit in flexion at postoperative 3 months or a return to the operating room for manipulation under anesthesia (MUA) and/or lysis of adhesions. RESULTS: A total of 58 (23.3%) patients developed postoperative arthrofibrosis, with 19 (7.6%) requiring a return to the operating room for MUA. Patients with arthrofibrosis were younger (mean ± SD, 11.3 ± 2.7 vs 12.3 ± 2.8 years; P = .029). They were more likely to have a nonsport, trauma-related injury (65.4% vs 32.1%; P < .001) and a concomitant ACL injury (10.3% vs 1.1%; P = .003). Those with arthrofibrosis had longer operative times (135.0 vs 114.8 minutes; P = .006) and were more likely to have been immobilized in a cast postoperatively (30.4% vs 16.6%; P = .043). In multivariate regression, concomitant anterior cruciate ligament (ACL) injury (odds ratio [OR], 20.0; P = .001), traumatic injury (OR, 3.8; P < .001), age <10 years (OR, 2.2; P = .049), and cast immobilization (OR, 2.4; P = .047) remained significant predictors of arthrofibrosis. Concomitant ACL injury (OR, 7.5; P = .030) was additionally predictive of a required return to the operating room for MUA. CONCLUSION: Surgeons should be cognizant of arthrofibrosis risk in younger patients with concomitant ACL tears and traumatic injuries not resulting from athletics. Furthermore, postoperative immobilization in a cast should be avoided given the high risk of arthrofibrosis. Concomitant ACL injury is associated with a higher return to the operating room for MUA.

Tibial Spine Fractures: How Much Are We Missing Without Pretreatment Advanced Imaging? A Multicenter Study.

BACKGROUND: There is a high rate of concomitant injuries reported in pediatric patients with tibial spine fractures, ranging from 40% to 68.8%. Many tibial spine fractures are treated without initial magnetic resonance imaging (MRI). PURPOSE: To understand rates of concomitant injury and if the reported rates of these injuries differed among patients with and without pretreatment MRI. STUDY DESIGN: Cross-sectional study; level of evidence, 3. METHODS: We performed an institutional review board-approved multicenter retrospective cohort study of patients treated for tibial spine fractures between January 1, 2000, and January 31, 2019, at 10 institutions. Patients younger than 25 years of age with tibial spine fractures were included. Data were collected on patient characteristics, injury, orthopaedic history, pretreatment physical examination and imaging, and operative findings. We excluded patients with multiple trauma and individuals with additional lower extremity fractures. Patients were categorized into 2 groups: those with and those without pretreatment MRI. The incidence of reported concomitant injuries was then compared between groups. RESULTS: There were 395 patients with a tibial spine fracture who met inclusion criteria, 139 (35%) of whom were reported to have a clinically significant concomitant injury. Characteristics and fracture patterns were similar between groups. Of patients with pretreatment MRI, 79 of 176 (45%) had an identified concomitant injury, whereas only 60 of 219 patients (27%) without pretreatment MRI had a reported concomitant injury (P < .001). There was a higher rate of lateral meniscal tears (P < .001) in patients with pretreatment MRI than in those without. However, there was a higher rate of soft tissue entrapment at the fracture bed (P = .030) in patients without pretreatment MRI. Overall, 121 patients (87%) with a concomitant injury required at least 1 treatment. CONCLUSION: Patients with pretreatment MRI had a statistically significantly higher rate of concomitant injury identified. Pretreatment MRI should be considered in the evaluation of tibial spine fractures to improve the identification of concomitant injuries, especially in patients who may otherwise be treated nonoperatively or with closed reduction. Further studies are necessary to refine the indications for MRI in patients with tibial spine fractures, determine the characteristics of patients at highest risk of having a concomitant injury, define the sensitivity and specificity of MRI in tibial spine fractures, and investigate patient outcomes based on pretreatment MRI status.

Do Year-Out Programs Make Medical Students More Competitive Candidates for Orthopedic Surgery Residencies?

OBJECTIVE: As orthopedic surgery residency programs are becoming more competitive, medical students interested in orthopedics are increasingly completing "year-out" programs. This study sought to evaluate student and faculty perceptions of these programs. DESIGN: A survey evaluating baseline characteristics was disseminated to directors of year-out programs identified through postings on the orthopedics forum, Orthogate.org. A second survey was sent to all program directors (PDs) of accredited US orthopedic residencies, while a final survey was distributed to participants identified by year-out PDs. SETTING: Ninety-six orthopedic year-out programs at 56 institutions were contacted. PARTICIPANTS: Twenty-six year-out programs, 72 PDs of ACGME-accredited orthopedic residencies, and 34 year-out participants from 6 programs completed our questionnaires. RESULTS: 73.1% (19) year-out program provided funding to participants, averaging $30,368. 84.6% (22) reported >75% match rates into orthopedics for participants. 65.4% (17) of programs selected students between their MS3/MS4 school years. 4.2% (3) of residency PDs agreed or strongly agreed that year-out programs were important factors for consideration in residency programs, compared with 82.4% (28) of year-out participants and 69.2% (18) of year-out PDs (p < 0.001). 58.8% (2) of year-out participants cited completion of a year-out for improving the chance of matching into any orthopedic residency, while 85.3% (29) wanted to be more competitive for top programs. The average Step 1 score was 248, which was insignificantly different from the national average for matched orthopedic applicants. CONCLUSIONS: Orthopedic year-out programs have dramatically increased in number over the last 20 years. Most of these programs are funded, 1-year clinical research fellowships with relative match success for participants pursuing orthopedic residencies. While year-out PDs and students consider participation in such programs to be an important factor for residency applications, and often participate in them in order to improve their competitiveness for matching at desired programs, residency PDs overall hold different views.

Analysis of Outcomes in Living Donor Liver Transplants Involving Reconstructive Microsurgeons.

BACKGROUND: Living donor transplantation is becoming increasingly popular as a modality for patients necessitating liver transplantation. Hepatic artery thrombosis (HAT) remains the most feared acute postoperative complication associated with living-donor liver transplantation. Preoperative planning, including scheduling reconstructive microsurgeons to perform the hepatic artery anastomosis using a surgical microscope or loupes, can decrease HAT rates. METHODS: A retrospective review of two reconstructive microsurgeons at a single institution was performed to analyze postoperative outcomes of adult and pediatric live donor liver transplants where reconstructive microsurgeons performed the hepatic artery anastomosis. One surgeon utilized the surgical microscope, while the other surgeon opted to use surgical loupes for the anastomosis. RESULTS: A total of 38 patients (30 adult and eight pediatric) met inclusion criteria for this study, and average patient age in the adult and pediatric population studied was 48.5 and 3.6 years, respectively. Etiologies of adult patients' liver failure were most commonly cholestatic (43%), followed by alcohol (23%), hepatitis C virus-related cirrhosis (17%), and nonalcoholic steatohepatitis (7%), while etiologies of pediatric liver failure were most commonly cholestatic (62.5%). None of the patients (0%) experienced acute postoperative HAT. On average, 22 and 25 months of postoperative follow-up was obtained for the adult and pediatric cohorts, respectively, and only one adult patient was found to have any liver-related complication. CONCLUSION: A collaborative relationship between reconstructive microsurgeons and transplant surgeons mitigates the risk of HAT and improves patient outcomes in living donor liver transplantation.

Lawnmower Injuries in Children: A National 13-Year Study of Urban Versus Rural Injuries.

INTRODUCTION: Although the American Academy of Orthopaedic Surgery, American Academy of Pediatrics, and Pediatric Orthopedic Society of North America have established lawnmower safety guidelines, a notable number of injuries continue to occur. We sought to elaborate on the epidemiology of lawnmower injuries in the pediatric age group and compare urban versus rural injuries. METHODS: The Pediatric Health Information System database was queried for patients of 1 to 18 years of age from 2005 to 2017 who presented with a lawnmower injury. Results were computed using bivariate tests and multinomial regressions. RESULTS: A total of 1,302 lawnmower injuries were identified (mean age 7.7 ± 5.1 years, range 1 to 18 years; 78.9% males). Incidence rates by region, adjusted for regional case volume, were 2.16 injuries per 100,000 cases in the South, 2.70 injuries per 100,000 cases in the Midwest, 1.34 injuries per 100,000 cases in the Northeast, and 0.56 injuries per 100,000 cases in the Western United States. After stratifying and adjusting for total case volume by locale (urban/rural), it was found that urban areas had an incidence rate of 1.47 injuries per 100,000 cases, whereas rural areas had a rate of 7.26 injuries per 100,000 cases. Rural areas had higher rates of infection and higher percentages of patients requiring inpatient stay. The surgical complication rate in rural areas was 5.5% as compared to 2.6% in urban areas. Based on urban/rural status, a significant difference was observed with the age group, length of stay, income, surgical complication, and presence of infection at the bivariate level with P < 0.05. Rural areas had an overall amputation rate of 15.5% compared with 9.6% in urban areas, with rural patients being 1.7 times more likely to undergo an amputation (P < 0.05). CONCLUSION: The findings of this study show that numerous geographic and locale disparities exist in pediatric lawnmower injuries and reveal the need for improved safety awareness, especially in at-risk rural populations.

Pediatric Type II Tibial Spine Fractures: Addressing the Treatment Controversy With a Mixed-Effects Model.

BACKGROUND: Tibial spine fractures, although relatively rare, account for a substantial proportion of pediatric knee injuries with effusions and can have significant complications. Meyers and McKeever type II fractures are displaced anteriorly with an intact posterior hinge. Whether this subtype of pediatric tibial spine fracture should be treated operatively or nonoperatively remains controversial. Surgical delay is associated with an increased risk of arthrofibrosis; thus, prompt treatment decision making is imperative. PURPOSE: To assess for variability among pediatric orthopaedic surgeons when treating pediatric type II tibial spine fractures. STUDY DESIGN: Cross-sectional study. METHODS: A discrete choice experiment was conducted to determine the patient and injury attributes that influence the management choice. A convenience sample of 20 pediatric orthopaedic surgeons reviewed 40 case vignettes, including physis-blinded radiographs displaying displaced fractures and a description of the patient's sex, age, mechanism of injury, and predominant sport. Surgeons were asked whether they would treat the fracture operatively or nonoperatively. A mixed-effects model was then used to determine the patient attributes most likely to influence the surgeon's decision, as well as surgeon training background, years in practice, and risk-taking behavior. RESULTS: The majority of respondents selected operative treatment for 85% of the presented cases. The degree of fracture displacement was the only attribute significantly associated with treatment choice (P < .001). Surgeons were 28% more likely to treat the fracture operatively with each additional millimeter of displacement of fracture fragment. Over 64% of surgeons chose to treat operatively when the fracture fragment was displaced by ≥3.5 mm. Significant variation in surgeon's propensity for operative treatment of this fracture was observed (P = .01). Surgeon training, years in practice, and risk-taking scores were not associated with the respondent's preference for surgical treatment. CONCLUSION: There was substantial variation among pediatric orthopaedic surgeons when treating type II tibial spine fractures. The decision to operate was based on the degree of fracture displacement. Identifying current treatment preferences among surgeons given different patient factors can highlight current variation in practice patterns and direct efforts toward promoting the most optimal treatment strategies for controversial type II tibial spine fractures.

MR imaging of the shoulder in youth baseball players: Anatomy, pathophysiology, and treatment.

With an increasing participation in youth sports and a growing popularity of overhead sports, shoulder pain and injuries are common in pediatric baseball players. In contrast to traumatic and collision injuries, which are more frequent with high-impact sports, many of the shoulder injuries are the result of repetitive overuse. Undiagnosed and untreated injury to the growth plates of skeletally immature athletes can lead to remodeling, which can negatively impact the biomechanics of the shoulder and produce long-term morbidity. Recently, there is an increasing emphasis on the association between skeletal maturation and injury patterns. The increasing use of magnetic resonance (MR) imaging has led to a better characterization of the traditionally radiographically-diagnosed growth plate injuries and awareness of other soft tissue and cartilaginous injuries that were previously thought to predominately occur in adult baseball players. The goal of this review is to: 1) highlight the normal anatomic changes that occur in the shoulder girdle during development and maturation; 2) discuss the biomechanical forces that are applied to the shoulder during a pitch; and 3) highlight the various injury patterns and adaptive remodeling that can occur in the shoulders of youth baseball athletes along with the current treatment options. These topics include growth plate injury, osteochondral injury, labral tear, capsular remodeling and rotator cuff tendinopathy.

Mechanical and Microstructural Properties of Pediatric Anterior Cruciate Ligaments and Autograft Tendons Used for Reconstruction.

BACKGROUND: Over the past several decades, there has been a steady increase in pediatric anterior cruciate ligament (ACL) tears, particularly in young female basketball and soccer players. Because allograft tissue for pediatric ACL reconstruction (ACLR) has shown high rates of failure, autograft tissue may be the best option for ACLR in this population. However, differences in the structure and mechanical behavior of these tissues are not clear. PURPOSE: To characterize the mechanical and microstructural properties in pediatric ACLs and autograft tissues using a rare cadaveric cohort (mean age, 9.2 years). STUDY DESIGN: Descriptive laboratory study. METHODS: ACLs, patellar tendons, quadriceps tendons, semitendinosus tendons, and iliotibial bands (ITBs) were harvested from 5 fresh-frozen pediatric knee specimens (3 male, 2 female) and subjected to a tensile loading protocol. A subset of contralateral tissues was analyzed using bright-field, polarized light, and transmission electron microscopy. RESULTS: Patellar tendons exhibited values for ultimate stress (5.2 ± 3.1 MPa), ultimate strain (35.3% ± 12.5%), and the Young modulus (27.0 ± 8.8 MPa) that were most similar to the ACLs (5.2 ± 2.2 MPa, 31.4% ± 9.9%, and 23.6 ± 15.5 MPa, respectively). Semitendinosus tendons and ITBs were stronger but less compliant than the quadriceps or patellar tendons. ITBs exhibited crimp wavelengths (27.0 ± 2.9 µm) and collagen fibril diameters (67.5 ± 19.5 nm) that were most similar to the ACLs (24.4 ± 3.2 µm and 65.3 ± 19.9 nm, respectively). CONCLUSION: The mechanical properties of the patellar tendon were almost identical to those of the ACL. The ITB exhibited increased strength and a similar microstructure to the native ACL. These findings are not entirely congruent with studies examining adult tissues. CLINICAL RELEVANCE: These results can be used to inform further clinical research. In particular, they justify a further examination of the biomechanical and microstructural properties of the ITB in the context of its role as an autograft tissue in pediatric ACL reconstruction.

Mechanical and Microstructural Properties of Native Pediatric Posterior Cruciate and Collateral Ligaments.

BACKGROUND: Although anterior cruciate ligament (ACL) tears have received the most attention, the medial collateral ligament (MCL) is thought to be the most commonly injured knee ligament overall. The lateral collateral ligament (LCL) and posterior collateral ligament (PCL) are less frequently compromised but can be involved in severe multiligament injuries. The paucity of information on the native properties of these ligaments in the pediatric population hinders the overall optimization of treatment for these injuries. PURPOSE: To characterize the mechanical and microstructural properties of pediatric MCLs, LCLs, and PCLs using a rare cadaveric cohort (mean age, 9.2 years). STUDY DESIGN: Descriptive laboratory study. METHODS: MCLs, LCLs, and PCLs were harvested from 5 fresh-frozen pediatric knee specimens (3 male, 2 female) and were subjected to a tensile loading protocol. A subset of contralateral tissues from a single donor was analyzed using bright-field, polarized light, and transmission electron microscopy to measure collagen fiber morphology. RESULTS: The pediatric MCL exhibited values for ultimate stress (11.7 ± 6.7 MPa), ultimate strain (18.2% ± 6.8%), and the Young modulus (93.7 ± 56.5 MPa) that were similar to values for the LCL (11.4 ± 11.5 MPa, 27.7% ± 12.9%, and 64.4 ± 76.6 MPa, respectively). The PCL demonstrated decreased ultimate stress (4.2 ± 1.8 MPa), increased ultimate strain (28.8% ± 11.9%), and a decreased Young modulus (19.8 ± 10.4 MPa) when compared with the MCL and LCL. All 3 ligaments had similar mean crimp wavelengths (MCL, 32.8 ± 3.6 µm; LCL, 27.2 ± 3.5 µm; PCL, 25.8 ± 3.5 µm) and collagen fibril diameters (MCL, 88.0 ± 26.0 nm; LCL, 93.3 ± 34.6 nm; PCL, 90.9 ± 34.0 nm); however, the fibril distribution profiles exhibited different modalities. CONCLUSION: The pediatric MCL and LCL possessed similar mechanical properties, while the pediatric PCL was weaker but capable of withstanding higher amounts of strain. All 3 of these pediatric structures were weaker than what has been reported in studies with adult cohorts. CLINICAL RELEVANCE: Results from this study can be considered preliminary mechanical and microstructural data for healthy pediatric collateral and posterior cruciate ligaments that can be used to guide further laboratory and clinical research.