Atypical Shoulder Instability Patterns in Adolescents Following Traumatic Anterior Shoulder Dislocation.

BACKGROUND: Traumatic anterior shoulder instability is common in the adolescent athlete, and when it is untreated, the recurrence rate is high. Atypical lesions-such as anterior glenoid periosteal sleeve, humeral glenohumeral ligament, and insertional tendon avulsions-may occur within this population, and accurate diagnosis and appropriate lesion management are key to treatment success. PURPOSE: To evaluate the age, skeletal immaturity, bone loss, and uncommon soft tissue lesions as correlates of posttraumatic anterior shoulder instability lesion patterns in an adolescent population. STUDY DESIGN: Cross-sectional study, Level of evidence, 3. METHODS: Consecutive patients ≤18 years of age (160 shoulders) treated within a single institution for traumatic anterior shoulder instability between June 2013 and June 2021 were reviewed. Demographics, injury mechanism, radiographic and magnetic resonance imaging of lesions, the presence of any bone loss, operative findings, and physeal status were recorded. An overall 131 shoulders met the inclusion criteria. Instability lesion type was analyzed categorically by age <15 or ≥15 years; individual age was assessed for correlation with any bone loss present. Atypical lesions-anterior labral periosteal sleeve avulsion, humeral avulsion of the glenohumeral ligament, subscapularis avulsion-were assessed for correlations with age, open physeal status, and the presence of any bone loss. RESULTS: An overall 131 shoulders (mean, 15.3 years; range, 10.5-18.3) were identified for this study: 55 in patients <15 years old and 76 in patients ≥15 years old. Bony injuries such as Bankart and Hill-Sachs lesions were more common in the ≥15-year-old group (P = .044 and P = .024, respectively). Bony Bankart injuries were found at a rate of 18.2% in the <15-year-old group, as compared with 34.2% in the ≥15-year-old group (P < .05). Anterior labral periosteal sleeve avulsions were more common in the <15-year-old group (n = 13 [23.6%] vs n = 8 [10.5%]; P < .044), as were all atypical lesions combined (n = 23 [41.8%] vs n = 13 [17.1%]; P < .0018]. CONCLUSION: In this series of anterior shoulder instability in children and adolescents, instability lesions varied significantly by age. Bone loss was associated with older age at presentation, and atypical lesions were more common in patients <15 years of age. Treatment teams should be aware of less common soft tissue injuries in this young age group and ensure careful review of adequate imaging for proper diagnosis and treatment in these younger patients.

Clinical and Radiographic Presentation of Capsular Iatrogenic Hip Instability After Previous Hip Arthroscopy.

BACKGROUND: The clinical and radiographic features of iatrogenic hip instability following hip arthroscopy have been described. However, the prevalence of presenting symptoms and associated imaging findings in patients with hip instability has not been reported. PURPOSE: To detail the prevalence of clinical and magnetic resonance arthrogram (MRA) findings in a cohort of patients with isolated hip instability and to determine midterm patient-reported outcomes in this patient population. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We retrospectively reviewed patients from 2014 to 2016 who underwent an isolated capsular repair in the revision hip arthroscopy setting. Patients were excluded if they underwent any concomitant procedures, such as labral repair, reconstruction, femoral osteoplasty, or any other related procedure. Several clinical data points were reviewed, including painful activities, mechanical symptoms, subjective instability, Beighton scores, axial distraction testing (pain, toggle, and apprehension), and distractibility under anesthesia. Patient-reported outcomes-including modified Harris Hip Score, Hip Outcome Score-Sports Subscale, Patient-Reported Outcome Measurement Information System (PROMIS) Physical Function Computer Adaptive Test, and a return patient hip questionnaire-were collected pre- and postoperatively. Pre-revision radiographs were obtained, and lateral center-edge angle and alpha angle were measured on anteroposterior and frog-leg lateral views, respectively. Pre-revision MRAs were reviewed and evaluated for capsular changes. Capsular changes were defined as follows: 0, normal; 1, capsular redundancy; 2, focal capsular rent; and 3, gross extravasation of fluid from the capsule. RESULTS: A total of 31 patients met inclusion criteria (5 male, 26 female; 14 right and 17 left hips). The mean age of patients was 36 years (range, 20-58 years). Overall, 27 (87%) reported hip pain with activities of daily living, and 31 (100%) experienced pain with sports or exercise. In addition, 24 (77%) had at least 1 positive finding on axial distraction testing. All patients had evidence of capsular changes on review of pre-revision MRAs. Out of 31 patients, 23 (74%) were available for follow-up at a minimum of 3.3 years and a mean ± SD of 4.6 ± 0.8 years. On average, modified Harris Hip Score improved by 20.3, Hip Outcome Score-Sports Subscale by 25.1, and PROMIS Physical Function Computer Adaptive Test by 6.4. Additionally, 20 (87%) patients reported improved or much improved physical ability, and 18 (78%) reported improved or much improved pain. CONCLUSION: The current study suggests that patients with hip instability demonstrate high rates of pain with activities of daily living and exercise, positive findings on axial distraction testing, and evidence of capsular changes on magnetic resonance imaging. Furthermore, these patients improve with revision surgery for capsular repair at midterm follow-up.

Anatomic Dissection and CT Imaging of the Anterior Cruciate and Medial Collateral Ligament Footprint Anatomy in Skeletally Immature Cadaver Knees.

BACKGROUND: Anterior cruciate ligament (ACL) and medial collateral ligament (MCL) injuries in skeletally immature patients are increasingly recognized and surgically treated. However, the relationship between the footprint anatomy and the physes are not clearly defined. The purpose of this study was to identify the origin and insertion of the ACL and MCL, and define the footprint anatomy in relation to the physes in skeletally immature knees. METHODS: Twenty-nine skeletally immature knees from 16 human cadaver specimens were dissected and divided into 2 groups: group A (aged 2 to 5 y), and group B (aged 7 to 11 y). Metallic markers were placed to mark the femoral and tibial attachments of the ACL and MCL. Computed tomography scans were obtained for each specimen used to measure the distance from the center of the ligament footprints to the respective distal femoral and proximal tibial physes. RESULTS: The median distance from the ACL femoral epiphyseal origin to the distal femoral physis was 0.30 cm (interquartile range, 0.20 to 0.50 cm) and 0.70 cm (interquartile range, 0.45 to 0.90 cm) for groups A and B, respectively. The median distance from the ACL epiphyseal tibial insertion to the proximal tibial physis for groups A and B were 1.50 cm (interquartile range, 1.40 to 1.60 cm) and 1.80 cm (interquartile range, 1.60 to 1.85 cm), respectively. The median distance from the MCL femoral origin on the epiphysis to the distal femoral physis was 1.20 cm (interquartile range, 1.00 to 1.20 cm) and 0.85 cm (interquartile range, 0.63 to 1.00 cm) for groups A and B, respectively. The median distance from the MCL insertion on the tibial metaphysis to the tibial physis was 3.05 cm (interquartile range, 2.63 to 3.30 cm) and 4.80 cm (interquartile range, 3.90 to 5.10 cm) for groups A and B, respectively. CONCLUSION: Surgical reconstruction is a common treatment for ACL injury. Computed tomography scanning of pediatric tissue clearly defines the location of the ACL and MCL with respect to the femoral and tibial physes, and may guide surgeons for physeal respecting procedures. CLINICAL RELEVANCE: In addition to ACL reconstruction, recent basic science and clinical research suggest that ACL repair may be more commonly performed in the future. MCL repair and reconstruction is also occasionally required in skeletally immature patients. This information may be useful to help surgeons avoid or minimize physeal injury during ACL/MCL reconstructions and/or repair in skeletally immature patients.

Traumatic Pediatric Quadriceps Rupture After Medial Patellofemoral Ligament Reconstruction: A Case Report.

CASE: A healthy 14-year-old boy, who presented with recurrent patellar instability, underwent medial patellofemoral ligament (MPFL) reconstruction. Four weeks following this operation, the patient slipped and fell while wearing his knee brace and was found to have sustained a quadriceps tendon rupture. CONCLUSIONS: We present a case of a rare, previously undescribed complication following an MPFL reconstruction in a young athlete. The etiology of this particular injury pattern may be due to a disruption of the vascular supply to the superior pole of the patella. Orthopaedic surgeons performing these reconstructions should be aware of this unusual complication.

Knee Extension Does Not Reliably Reduce Acute Type II Tibial Spine Fractures: MRI Evaluation of Displacement During Extension Versus Resting Flexion.

BACKGROUND: Type II tibial spine avulsion (TSA) fractures have traditionally been managed by first attempting to achieve closed reduction with extension and immobilization, with surgical indications reserved for those who fail to reduce within 3 mm. However, the frequency with which appropriate reduction can be achieved is largely unknown. PURPOSE: To evaluate changes in displacement of type II TSA fractures by comparing magnetic resonance imaging (MRI) scans obtained with the knee in flexion and in extension. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Ten patients with type II TSA fractures were identified. Fracture displacement was measured using 3 images for each patient: (1) initial lateral view radiography, (2) sagittal-plane MRI of the knee in resting flexion, and (3) sagittal-plane MRI of the knee in passive extension. Maximum displacement of the bony fragment was measured in the 2 MRI studies for all patients, and the corresponding change in displacement was calculated. Displacement in flexion was compared with displacement in extension using a paired-sample t test. Statistical significance was set at P < .05. RESULTS: The displacement distance of the bony fragment was reduced by a mean of 0.97 mm on MRI when the knee was in extension compared with flexion in patients with type II TSA fractures (P = .02). Mean displacement with extension was 6.14 mm, with no fractures reduced below 4 mm. The largest reduction observed was 2.80 mm. The displacement distance increased in 2 knees with extension. The intermeniscal ligament (IML) was entrapped in 4 of 10 patients; however, the amount of reduction achieved did not differ based on the presence of IML entrapment (P = .85). CONCLUSION: While the amount of tibial spine displacement warranting surgical treatment can be debated, the study findings suggest that knee extension is not reliable in obtaining adequate closed reduction for type II TSA fractures. Management decisions may need to be based on the initial displacement distance of the fracture, with a lower threshold for operative treatment than previously recognized.

The Position of the Popliteal Artery and Peroneal Nerve Relative to the Menisci in Children: A Cadaveric Study.

BACKGROUND: Meniscal injury in skeletally immature patients is increasingly reported. During meniscal repair, all-inside devices may protrude beyond the posterior limits of the meniscus, putting the neurovascular structures at risk. PURPOSE: The purposes of this study were (1) to examine the relationship between the popliteal artery and the posterolateral and posteromedial aspects of the menisci, (2) to examine the relationship of the peroneal nerve to the posterolateral meniscus, and (3) to develop recommendations for avoiding neurovascular injury during posterior meniscal repair in pediatric patients. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 26 skeletally immature knee cadaveric specimens (7 females and 19 males) were included. Specimens were divided into age groups: 2-4, 5-8, and 9-11 years. The most posterior extent of the lateral and medial menisci was identified via sagittal and axial views on computed tomography (CT) scans. The shortest distance from the most posterior aspect of the lateral and medial menisci to the popliteal artery and the shortest distance from the posterior aspect of the lateral menisci to the anterior rim of the peroneal nerve were measured, and 3-dimensional models of representative specimens were re-created through use of CT scans. RESULTS: For the age groups 2-4, 5-8, and 9-11 years, the mean minimum distance from the posterolateral meniscus to the popliteal artery was 5.2, 6.7, and 8.2 mm, respectively, and the mean minimum distance from the posteromedial meniscus to the popliteal artery was 12.7, 15.4, and 20.3 mm, respectively. In all groups, the distance between the posteromedial meniscus and the popliteal artery was greater than that between the posterolateral meniscus and the popliteal artery. The mean distance from the peroneal nerve to the lateral meniscus was 13.3, 15.0, and 17.9 mm for the respective groups. CONCLUSION: Many all-inside meniscal repair devices have sharp tips that penetrate posterior to the meniscus and capsule. This study demonstrated that the distance between the posterior meniscus and popliteal artery is relatively small in pediatric patients, especially for the lateral meniscus region. CLINICAL RELEVANCE: Because of the higher potential for meniscal healing, meniscal repair is more likely to be performed in pediatric patients. The data in this study regarding the proximity of the lateral meniscus and neurovascular structures may be used to guide safe surgical repair of posterior meniscal tears during the use of all-inside meniscal repair devices in these patients.

What are the Demographics and Epidemiology of Legg-Calvé-Perthes Disease in a Large Southern California Integrated Health System?

BACKGROUND: Although many authors have reported the incidence of Legg-Calvé-Perthes disease (LCPD), there have been few incidence studies in the United States on large, self-contained populations such as those within an integrated health system. Understanding the epidemiology and demographics of LCPD in this setting may help clinicians identify patients at the greatest risk and aid in diagnosis and subsequent treatment. QUESTIONS/PURPOSES: In this study we sought (1) to determine the incidence and demographics of LCPD in a large cohort of children and adolescents in a Southern California integrated healthcare system, and (2) to identify any demographic or clinical factors (such as age, sex, race/ethnicity, or BMI) that are independently associated with LCPD. METHODS: A retrospective chart analysis was done on patients diagnosed with LCPD within our integrated healthcare system in patients aged 2 to 12 years over a 3-year period between 2010-2012. There were nearly 800,000 children in this cohort. Patient demographics were recorded; the incidence of LCPD was determined for the entire group and by sex, age, and race/ethnicity. Odds ratios for an association with LCPD based on age, sex, BMI and race/ethnicity were determined using logistic regression models. RESULTS: The LCPD incidence per 100,000 for all children was 2.84, with the highest incidence in 2- to 5-year-old children (3.05; 95% CI, 1.51-4.59) and the lowest in 9- to 12-year-old children (1.06; 95% CI, 0.21-1.91). Incidence varied markedly among ethnicities, with the highest incidence in whites (5.69; 95% CI, 3.13-8.24) and the lowest in Asians (0.78; 95% CI, 0.00-2.32). Data analysis revealed a 3.13-times increased odds ratio (OR) of LCPD in 2- to 5-year-old patients versus 9- to 12-year-olds (p = 0.011), and boys had a 12.44 times greater OR of LCPD than girls (p < 0.001). Data analysis showed an increased OR for LCPD (3.41; 95% CI, 1.28-9.09) in patients with extreme obesity (BMI-for-age ≥ 1.2 × 95th percentile or a BMI ≥ 35 kg/m) compared with patients with a normal BMI. CONCLUSIONS: Our study of a large integrated healthcare system in Southern California revealed an increased association of male sex and young age (2 to 5 years old) with LCPD. The overall incidence was lower overall than previously reported, although the incidence seen in white patients was similar to that in prior studies. The finding that patients with extreme obesity may have an increased association with LCPD merits further study. These findings may increase providers' awareness of the risk of the disease in younger patients and in extremely obese patients, and it also merits further future investigation as to whether there is a cause or effect relationship between extreme obesity and LCPD. LEVEL OF EVIDENCE: Level IV, prognostic study.

Biomechanical Comparison of Epiphyseal Anterior Cruciate Ligament Fixation Using a Cortical Button Construct Versus an Interference Screw and Sheath Construct in Skeletally Immature Cadaveric Specimens.

BACKGROUND: Anterior cruciate ligament (ACL) ruptures have become increasingly common in pediatric and adolescent athletes. While multiple methods exist, all-epiphyseal ACL reconstruction is a popular technique in the skeletally immature patient. Given the high rate of reruptures in this population and the increasing number of commercially available fixation devices, biomechanical testing is crucial to understand the performance of these devices in pediatric epiphyseal bone. To our knowledge, there has not been a biomechanical analysis of ACL fixation devices in skeletally immature bone. PURPOSE: To compare cortically based button fixation with interference screw and sheath fixation in skeletally immature femoral epiphyseal cadaveric bone. Our hypothesis was that there would be no difference in peak load to failure, stiffness, or cyclic displacement between these 2 fixation constructs. STUDY DESIGN: Controlled laboratory study. METHODS: Fresh-frozen matched-pair knees from 3 pediatric cadaveric specimens were obtained. A synthetic graft was fixed in an all-epiphyseal femoral tunnel. Both the lateral and medial condyles were utilized to increase the sample size. Specimens were randomized and assigned to receive either an interference screw and sheath construct designed for pediatric patients or an adjustable loop cortical button. Biomechanical testing was performed to obtain ultimate load to failure, stiffness, total displacement after 500 cycles, and the failure mode for each condyle. RESULTS: Each medial and lateral condyle in 3 pairs of skeletally immature cadaveric knees (ages 7, 9, and 11 years) was utilized for testing. One specimen was excluded after it failed by having a transphyseal fracture. The median peak load to failure was 769.80 N (interquartile range [IQR], 628.50-930.41 N) for the screw and sheath group and 862.80 N (IQR, 692.34-872.65 N) for the button group (P = .893). The median displacement after 500 cycles for the screw and sheath group was 0.65 mm (IQR, 0.47-1.03 mm) and 1.13 mm (IQR, 0.96-1.25 mm) for the button group (P = .08). The median stiffness of the screw and sheath group was significantly higher than that of the button group (31.47 N/mm [IQR, 26.40-43.00 N/mm] vs 25.22 N/mm [IQR, 21.18-27.07 N/mm], respectively) (P = .043). CONCLUSION: When comparing femoral fixation with a screw and sheath construct developed for pediatric patients to an adjustable loop cortical button in skeletally immature bone, our results showed that fixation did not significantly differ with respect to cyclic displacement or peak load to failure. While the screw and sheath construct was significantly stiffer, its effect on clinical outcomes is not yet known. CLINICAL RELEVANCE: With regard to femoral fixation, there is no significant biomechanical difference between the use of cortically based button fixation or interference screw and sheath fixation in pediatric epiphyseal cadaveric bone.

Childhood Obesity is Associated With Osteochondritis Dissecans of the Knee, Ankle, and Elbow in Children and Adolescents.

BACKGROUND: Osteochondritis dissecans (OCD) is a joint disorder of the subchondral bone and articular cartilage whose association with obesity in children is not clearly known. The purpose of this study was to assess the magnitude of the association between childhood obesity and the occurrence of OCD of the knee, ankle, and elbow in children. METHODS: A retrospective chart review of an integrated health system was performed on OCD patients aged 2 to 19 from 2007 to 2011, with over 1 million patients in this cohort. Lesion location, laterality, and all patient demographics were recorded. The body mass index (BMI) for each patient in the cohort was used to stratify patients into 5 weight classes (underweight, normal weight, overweight, moderately obese, and extremely obese) based on BMI-for-age. The associations between the 5 weight classes and OCD of the ankle, knee, and elbow were assessed using multiple logistic regression models to estimate odds ratios (OR) and 95% confidence intervals using multivariate analysis to adjust for patient demographic variables. RESULTS: In total, 269 patients fit the inclusion criteria. Mean BMI, both absolute and percentile, was significantly higher for patients with OCD of the knee, elbow, and ankle than patients without OCD. In the multivariate analysis, extremely obese patients were found to have an increased OR of OCD for all patients, with an 86% increased risk of any OCD compared with normal weight patients. In addition, assessment by different types of OCD revealed that extremely obese patients had an increased OR of OCD of the elbow and ankle individually, with a 3.1 times increased OCD elbow risk and 3.0 times increased risk of ankle OCD in extremely obese patients. Although extremely obese patients did not have a statistically significant increased risk of knee OCD, moderately obese patients did have a 1.8 times increased risk of knee OCD as compared with normal weight children. There were no significantly different risks of any type of OCD seen in overweight or underweight patients as compared with normal weight patients. CONCLUSIONS: In this population-based cohort study, extreme obesity is strongly associated with an increased risk of OCD overall and OCD of the elbow and ankle specifically. In addition, moderate obesity is associated with an increased risk of knee OCD. All types of OCD were also found to have a significantly greater average BMI when compared with patients without OCD. LEVEL OF EVIDENCE: Level IV-descriptive epidemiology study.

Incidence of Osteochondritis Dissecans in Adults.

BACKGROUND: Osteochondritis dissecans (OCD) has frequently been described in children and adolescents, but cases of OCD in adults are certainly encountered. Little has been published on the epidemiology of OCD in adult patients. PURPOSE: To assess the frequency of OCD lesions in adults and assess the risk by age, sex, and ethnicity. STUDY DESIGN: Descriptive epidemiology study. METHODS: The authors assessed all patients aged 20 to 45 years from the entire database of patients enrolled as members of Kaiser Permanente Southern California from January 2011 until December 2013. Kaiser Southern California is an integrated health care system serving a racially, ethnically, and socioeconomically diverse population of >3.5 million patients. A retrospective chart review was done on OCD during this period. Inclusion criteria included OCD of any joint. Exclusion criteria included traumatic osteochondral fractures and coexistence of intra-articular lesions other than OCD. Joint involvement/location, laterality, and all patient demographics were recorded. RESULTS: Among 122 patients, a total of 124 OCD lesions were found. The majority of lesions were in the ankle (n = 76) and knee (n = 43), with 3 foot lesions and 2 elbow lesions identified. OCD lesions were identified in 75 men (62%) and 47 women (38%). Overall incidence rates per 100,000 person-years were 3.42 for all OCD, 2.08 for ankle OCD, and 1.21 for knee OCD. The relative risk of adult OCD for men was twice that of women. The relative risk of adult OCD for white patients was 2.3 that of Asians and 1.7 that of Hispanics. Risk of knee OCD was 3.6 times higher for men than women. As compared with women, men had a higher risk for lateral femoral condyle OCD lesions versus the medial femoral condyle ( P = .05; odds ratio [OR], 5.19). CONCLUSION: This large cohort study of Southern California adults with OCD demonstrated an increased OR for men (vs women) of OCD in all joints. The majority of symptomatic lesions were present in the ankle rather than the knee, as previously found in children. White and black patients had the highest OR of OCD; men had a significantly greater OR of lateral femoral condyle knee lesions as compared with women.

All-Epiphyseal Anterior Cruciate Ligament Femoral Tunnel Drilling: Avoiding Injury to the Physis, Lateral Collateral Ligament, Anterolateral Ligament, and Popliteus-A 3-Dimensional Computed Tomography Study.

PURPOSE: To investigate the relation of the at-risk structures (distal femoral physis, lateral collateral ligament, anterolateral ligament, popliteus, and articular cartilage) during all-epiphyseal femoral tunnel drilling. A second purpose was 2-fold: (1) to develop recommendations for tunnel placement and orientation that anatomically reconstruct the anterior cruciate ligament (ACL) while minimizing the risk of injury to these at-risk structures, and (2) to allow for maximal tunnel length to increase the amount of graft in the socket to facilitate healing. METHODS: Three-dimensional models of 6 skeletally immature knees (aged 7-11 years) were reconstructed from computed tomography and used to simulate all-epiphyseal femoral tunnels. Tunnels began within the ACL footprint and were directed laterally or anterolaterally, with the goal of avoiding injury to at-risk structures. The spatial relation between the ideal tunnel and these structures was evaluated. Full-length tunnels and partial length condyle sockets were simulated in the models using the same trajectories. RESULTS: An anterolateral tunnel could be placed to avoid direct injury to lateral structures. The safe zone on the anterolateral aspect of the femur was larger than that of a tunnel with a direct lateral trajectory (median 127 mm2 vs 83 mm2, P = .028). Anterolateral tunnels were longer than direct lateral tunnels (median 30 mm vs 24 mm, P = .041). Safe angles for anterolateral tunnels were 34° to 40° from the posterior condylar axis; direct lateral tunnels were drilled 4° to 9° from the posterior condylar axis. Sockets could be placed without direct injury to structures at risk with either orientation. CONCLUSIONS: An all-epiphyseal ACL femoral tunnel can be placed without causing direct injury to at-risk structures. A tunnel angled anterolaterally from the ACL origin is longer and has a larger safe zone compared with the direct lateral tunnel. CLINICAL RELEVANCE: The largest safe zone for femoral all-epiphyseal ACL drilling was (1) anterior to the lateral collateral ligament origin, (2) distal to the femoral physis, and (3) proximal to the popliteus tendon origin. A direct lateral tunnel may also be used, but has a smaller safe zone. Sockets or partial length tunnels may have a lower risk of injury to at-risk structures.

Demographics and Epidemiology of Osteochondritis Dissecans of the Elbow Among Children and Adolescents.

BACKGROUND: Osteochondritis dissecans (OCD) of the elbow is a disorder of subchondral bone and articular cartilage, of which the incidence among children is not clearly known. PURPOSE: To assess the demographics and epidemiology of OCD of the elbow among children. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A retrospective chart review of an integrated health system for the years 2007 through 2011 was performed for patients with elbow OCD aged 2 to 19 years. Lesion location, laterality, and all patient demographics were recorded. OCD incidence was determined for the group as a whole as well as by sex and age group (2-5, 6-11, 12-19 years). Patient differences based on age, sex, and ethnicity were analyzed, and multivariable logistic regression models were used to assess the risk of elbow OCD by group. RESULTS: A total of 37 patients with 40 OCD lesions fit the inclusion criteria. No lesion was found among 2- to 5-year-olds. A majority of lesions (n = 39, 97.5%) were in the capitellum, and 1 (2.5%) was in the trochlea. Twenty-five patients (67.6%) had right-sided lesions; 9 (24.3%), left-sided; and 3 (8.1%), bilateral. The incidence of elbow OCD for patients aged 6 to 19 years was 2.2 per 100,000 overall and 3.8 and 0.6 per 100,000 for males and females, respectively. The majority of OCD cases were seen in those aged 12 to 19 years, with an incidence of 3.4 per 100,000 versus 0.38 among 6- to 11-year-olds. Multivariable logistic regression analysis revealed a 21.7-times increased odds ratio of elbow OCD among patients aged 12 to 19 years versus 6 to 11 years, and males had a 6.8-times greater odds ratio of elbow OCD than females (P < .0001 for both). Based on race and ethnicity, non-Hispanic whites had the highest incidence of elbow OCD as compared with all other ethnic groups. CONCLUSION: In this population-based cohort study of pediatric elbow OCD, males had almost 7 times the risk of elbow OCD as compared with females, and 12- to 19-year-olds had nearly 22 times the risk of elbow OCD versus 6- to 11-year-olds. In keeping with many prior studies, the majority of patients had right-sided lesions.

Incidence of Meniscal Entrapment and Associated Knee Injuries in Tibial Spine Avulsions.

BACKGROUND: Tibial spine avulsions (TSA) have historically been treated as isolated injuries. Data on associated injuries are limited with existing literature reporting wide ranging incidences. The purpose of this multicenter study was to (1) describe the incidence of meniscal entrapment and associated knee injuries in TSA and to (2) compare surgical and magnetic resonance image (MRI) findings for these injuries. Our hypothesis is that tibial spine injuries are not usually isolated injuries, and other meniscal, ligament, and cartilage injuries may be present. METHODS: MRI and surgical reports for patients with a diagnosis of a tibial spine fracture were retrospectively reviewed. Type of fracture was recorded as noted in the reports along with concomitant meniscal entrapment and osteochondral, ligamentous, and meniscal injury. Images and reports were reviewed by an orthopaedic surgeon at each respective institution. RESULTS: A total of 163 patients were included in this study. MRI was done for 77 patients and surgery was performed in 144 cases. Meniscal entrapment was found in 39.9% of all patients. MRI diagnosed meniscus, osteochondral, and non-anterior cruciate ligament ligamentous injury was found in 31.2%, 68.8%, and 32.4% of cases, respectively. Surgically diagnosed meniscus, chondral, and non-anterior cruciate ligament ligamentous injury was found in 34.7%, 33.3%, and 5.6% of patients, respectively. CONCLUSIONS: TSA fractures are associated with significant risk for concomitant knee injuries including meniscal tear, bone contusion, and chondral injury. Incidence of meniscal entrapment found during surgery was high, in spite of low incidence of positive findings by MRI. LEVEL OF EVIDENCE: Level IV-retrospective case series.

Variation in the Medial Patellofemoral Ligament Origin in the Skeletally Immature Knee: An Anatomic Study.

BACKGROUND: The medial patellofemoral ligament (MPFL) is frequently reconstructed to treat recurrent patellar instability. The femoral origin of the MPFL is well described in adults but not in the skeletally immature knee. PURPOSE: To identify a radiographic landmark for the femoral MPFL attachment in the skeletally immature knee and study its relationship to the distal femoral physis. STUDY DESIGN: Descriptive laboratory study. METHODS: Thirty-six cadaveric specimens between 2 and 11 years old were dissected and examined (29 male and 7 female). Metallic markers were placed at the proximal and distal borders of the MPFL femoral origin footprint. Computed tomography scans with 0.625-mm slices in the axial, coronal, and sagittal planes were used to measure the maximum ossified height and ossified depth. The measurements were used to describe the position of the midpoint MPFL attachment with respect to the posterior-anterior and distal-proximal dimensions of the femoral condyle on the sagittal view and to describe the distance from the physis to the femoral origin of the MPFL. RESULTS: In 23 of 36 specimens, the femoral origin of the MPFL was distal to the physis. Thirteen of the 36 specimens had an MPFL origin at or proximal to the physis, with a more proximal MPFL origin consistently seen in older specimens. The distance of the MPFL origin to the physis ranged from 15.1 mm distal to the physis to 8.3 mm proximal to the physis. The mean midpoint of the MPFL femoral origin was located 3.0 ± 5.5 mm distal to the physis for all specimens. For specimens aged <7 years, the mean MPFL origin was 4.7 mm distal to the physis, and for specimens aged ≥7 years, the mean MPFL origin was 0.8 mm proximal to the femoral physis. The MPFL origin was more proximal and anterior for those aged ≥7 years and more distal and posterior for those aged <7 years. CONCLUSION: Surgical reconstruction of the MPFL is a common treatment to restore patellar stability. There appears to be significant variability in the origin of the MPFL in skeletally immature specimens. This study demonstrated that the MPFL origin was more proximal and anterior with respect to the physis in the older age group. The MPFL origin footprint may be customized for different age groups. CLINICAL RELEVANCE: This information shows anatomic variation of the MPFL origin with age, with older specimens having a footprint that was more proximal and anterior than younger specimens. Customization of the surgical technique might be considered based on patient age.

Lateral Radiographic Landmarks for ACL and LCL Footprint Origins During All-Epiphyseal Femoral Drilling in Skeletally Immature Knees.

BACKGROUND: This study was conducted to evaluate the spatial relationship of the anterior cruciate ligament (ACL) and lateral collateral ligament (LCL) femoral footprint origins in knee specimens from skeletally immature donors as viewed on lateral radiographs. METHODS: Fourteen cadaver specimens of skeletally immature knees from children between 7 and 11 years old at the time of death were examined through gross dissection. Metallic pins were placed at the center of the ACL and LCL femoral footprints, and computed tomography (CT) scans were performed. Sagittal plane CT images were merged to create a view analogous to an intraoperative C-arm image with overlaid ACL and LCL ligament footprints. Ligament origins were then measured as a percent of the epiphyseal depth (% P-A [posterior-anterior]) and height (% P-D [proximal-distal]). RESULTS: The ACL origin was centered at a point located 14% (14% P-A) of the total lateral femoral condyle (LFC) depth from the most posterior aspect of the LFC and 38% (38% P-D) of the LFC height from the most proximal aspect of the posterior physis. The LCL origin was centered at a point 27% P-A and 37% P-D. When viewed on a sagittal CT reconstruction analogous to a perfect lateral intraoperative fluoroscopic view, the ACL footprint origin is posterior and slightly inferior to the LCL origin. Both origins are distal to the distal femoral physis and are posterior to the origin of the popliteus. CONCLUSIONS: This study demonstrates a consistent relationship between the origin of the ACL and LCL, which may be useful in guiding safe tunnel placement during all-epiphyseal ACL reconstruction in skeletally immature knees. CLINICAL RELEVANCE: This anatomic reference can be used intraoperatively to guide and radiographically evaluate ACL tunnel placement while avoiding the LCL origin in skeletally immature patients.

Anterolateral Ligament of the Knee Shows Variable Anatomy in Pediatric Specimens.

BACKGROUND: Anterior cruciate ligament (ACL) reconstruction failure rates are highest in youth athletes. The role of the anterolateral ligament in rotational knee stability is of increasing interest, and several centers are exploring combined ACL and anterolateral ligament reconstruction for these young patients. Literature on the anterolateral ligament of the knee is sparse in regard to the pediatric population. A single study on specimens younger than age 5 years demonstrated the presence of the anterolateral ligament in only one of eight specimens; therefore, much about the prevalence and anatomy of the anterolateral ligament in pediatric specimens remains unknown. QUESTIONS/PURPOSES: We sought to (1) investigate the presence or absence of the anterolateral ligament in prepubescent anatomic specimens; (2) describe the anatomic relationship of the anterolateral ligament to the lateral collateral ligament; and (3) describe the anatomic relationship between the anterolateral ligament and the physis. METHODS: Fourteen skeletally immature knee specimens (median age, 8 years; range, 7-11 years) were dissected (12 male, two female specimens). The posterolateral structures were identified in all specimens, including the lateral collateral ligament and popliteus tendon. The presence or absence of the anterolateral ligament was documented in each specimen, along with origin, insertion, and dimensions, when applicable. The relationship of the anterolateral ligament origin to the lateral collateral ligament origin was recorded. RESULTS: The anterolateral ligament was identified in nine of 14 specimens. The tibial attachment point was consistently located in the same region on the proximal tibia, between the fibular head and Gerdy's tubercle; however, the femoral origin of the anterolateral ligament showed considerable variation with respect to the lateral collateral ligament origin. The median femoral origin of the anterolateral ligament was 10 mm (first interquartile 6 mm, third interquartile 13) distal to the distal femoral physis, whereas its median insertion was 9 mm (first interquartile 5 mm, third interquartile 11 mm) proximal to the proximal tibial physis. CONCLUSIONS: The frequency of the anterolateral ligament in pediatric specimens we observed was much lower than other studies on adult specimens; future studies might further investigate the prevalence, development, and functional role of the anterolateral ligament of the knee. CLINICAL RELEVANCE: This study expands our understanding of the anterolateral ligament and provides important anatomic information to surgeons considering anterolateral ligament reconstruction concomitantly with primary or revision ACL reconstruction in pediatric athletes.

The Relationship of the Femoral Physis and the Medial Patellofemoral Ligament in Children: A Cadaveric Study.

BACKGROUND: Young athletes sustain patellar dislocations in a variety of sports. The medial patellofemoral ligament (MPFL) is a critical structure that functions as an anatomic checkrein to help prevent lateral patellar dislocation. Reconstruction of this ligament is challenging in patients with open physes because of concerns about iatrogenic damage to the femoral physis. PURPOSE: To evaluate the relationship of the distal femoral physis and the MPFL. STUDY DESIGN: Descriptive laboratory study. METHODS: In 15 cadaveric, pediatric knees (age, 7-11 years), markers were placed at the proximal/distal limits of the MPFL femoral attachment and were evaluated with computed tomography. The distance from the MPFL attachment midpoint to the most medial aspect of the distal femoral physis was measured. RESULTS: The mean femoral width of the MPFL was 8.1 mm (range, 4.3-13.8 mm). The femoral MPFL midpoint was distal to the femoral physis in 11 specimens and proximal to the physis in 4 specimens. The most proximal portion of the MPFL femoral attachment extended above the medial physis in 7, was at the physis in 5, and was below the physis in 3 specimens. One specimen had the entire MPFL femoral attachment above the physis. For knees with the MPFL midpoint above the medial physis, the distance between the center of the MPFL and physis was 3.3 mm (range, 0.3-7.1 mm). For knees with the MPFL below the medial physis, the distance between the center of the MPFL and physis was -6.8 mm (range, -0.7 to -22.0 mm). CONCLUSION: The relationship of the femoral attachment of the MPFL and the medial femoral physis shows some anatomic variation. In all cases, the MPFL is close to the medial femoral physis, but the midpoint of the MPFL is at, slightly above, or slightly below the physis. CLINICAL RELEVANCE: The relationship of the MPFL femoral attachment footprint to the femoral physis in the skeletally immature patient is not well understood, and access to pediatric cadaveric tissue is very limited. This small series demonstrates that there is considerable variation in the relationship between the MPFL and distal femoral physis. This anatomic information may guide MPFL reconstruction technique in young patients and reduce the risk of iatrogenic physeal arrest on the femur.

The Incidence of Surgery in Osteochondritis Dissecans in Children and Adolescents.

BACKGROUND: The frequency of osteochondritis dissecans (OCD), a disorder of the subchondral bone and articular cartilage, is not well described. PURPOSE: To assess the frequency of pediatric OCD lesions that progress to surgery based on sex, joint involvement, and age. STUDY DESIGN: Descriptive epidemiology study. METHODS: A retrospective chart review (2007-2011) was performed on OCD. Inclusion criteria included OCD of any joint and patients aged 2 to 19 years. Exclusion criteria included traumatic osteochondral fractures or coexistence of non-OCD intra-articular lesions. Differences in progression toward surgery were compared between age groups, sex, and joint location. Logistical regression analysis was performed by sex, age, and ethnicity. RESULTS: Overall, 317 patients with a total of 334 OCD lesions were found. The majority of lesions (61.7%) were in the knee, with ankle, elbow, shoulder, and foot lesions representing 25.4%, 12.0%, 0.6%, and 0.3% of all lesions, respectively. The majority of joints needing surgery were in the knee (58.5%), with ankle and elbow lesions representing 22.9% and 18.6% of surgeries performed, respectively. The percentage of all OCD lesions progressing to surgery was 35.3%; surgical progression for knee, ankle, and elbow joints was 33.5%, 31.8%, and 55.0%, respectively. Logistic regression analysis found no statistically significant different risk of progressing to surgery for OCD of the knee, elbow, and ankle between sexes. Patients aged 12 to 19 years had a 7.4-times greater risk of progression to surgery for knee OCD lesions than 6- to 11-year-olds. Patients aged 12 to 19 years were 8.2 times more likely to progress to surgery for all OCD lesions than patients aged 6 to 11 years. Progression to surgery of ankle OCD did not significantly differ based on location. Three of 4 trochlear lesions progressed to surgery, along with 1 of 1 tibial, 1 of 3 patellar, 40.3% of lateral femoral condylar, and 28.2% of medial femoral condylar lesions. CONCLUSION: In this large cohort study of pediatric OCD patients, 35% progressed to surgery. Progression to surgery did not differ significantly between sexes with OCD of any joint. Progression to surgery for OCD of the knee, elbow, and ankle strongly correlated with patient age at the time of diagnosis. CLINICAL RELEVANCE: The knowledge of likelihood of progression to surgery of OCD by location, sex, and age is useful in counseling patients and in planning treatment. This study confirms a worse prognosis in the nonoperative treatment of older patients with OCD.

Surgeon-Directed Cost Variation in Isolated Rotator Cuff Repair.

BACKGROUND: As value becomes a larger component of heath care decision making, cost data can be evaluated for regional and physician variation. Value is determined by outcome divided by cost, and reducing cost increases value for patients. "Third-party spend" items are individual selections by surgeons used to perform procedures. Cost data for third-party spend items provide surgeons and hospitals with important information regarding care value, potential cost-saving opportunities, and the total cost of ownership of specific clinical decisions. PURPOSE: To perform a cost review of isolated rotator cuff repair within a regional 7-hospital system and to document procedure cost variation among operating surgeons. STUDY DESIGN: Economic and decision analysis; Level of evidence, 4. METHODS: Current Procedural Terminology (CPT) codes were used to retrospectively identify subjects who received an isolated rotator cuff repair within a 7-hospital system. Cost data were collected for clinically sensitive third-party spend items and divided into 4 cost groups: (1) suture anchors, (2) suture-passing devices and needles, (3) sutures used for cuff repair, and (4) disposable tools or instruments. RESULTS: A total of 62 isolated rotator cuff repairs were performed by 17 surgeons over a 13-month period. The total cost per case for clinically sensitive third-party spend items (in 2015 US dollars) ranged from $293 to $3752 (mean, $1826). Four surgeons had a mean procedure cost that was higher than the data set mean procedure cost. The cost of an individual suture anchor ranged from $75 to $1775 (mean, $403). One disposable suture passer was used, which cost $140. The cost of passing needles ranged from $140 to $995 (mean, $468). The cost per repair suture (used to repair cuff tears) varied from $18 to $298 (mean, $61). The mean suture (used to close wounds) cost per case was $81 (range, $0-$454). A total of 316 tools or disposable instruments were used, costing $1 to $1573 per case (mean, $624). CONCLUSION: This study demonstrates significant cost variation with respect to cost per case and cost of individual items used during isolated rotator cuff repair. Suture anchors represent the most expensive and variable surgeon-directed cost. The wide cost variation seen in all cost categories illustrates both the effect of surgeon choice in procedure cost and the opportunity for significant cost savings in cases of isolated rotator cuff repair. Engaging surgeons in discussion on cost can positively influence the value of care provided to patients if costs can be reduced without affecting the quality of patient outcomes.

Facile formation of ß-hydroxyboronate esters by a Cu-catalyzed diboration/Matteson homologation sequence.

The copper-catalyzed diboration of aldehydes was used in conjunction with the Matteson homologation, providing the efficient synthesis of ß-hydroxyboronate esters. The oxygen-bound boronate ester was found to play a key role in mediating the homologation reaction, which was compared to the α-hydroxyboronate ester (isolated hydrolysis product). The synthetic utility of the diboration/homologation sequence was demonstrated through the oxidation of one product to provide a 1,2-diol.