Decreased Posterior Tibial Slope and Its Association With Pediatric Posterior Cruciate Ligament Injury.

BACKGROUND: Recent adult studies have demonstrated that decreased posterior tibial slope angle (PTSA) may be a risk factor for posterior cruciate ligament (PCL) injury. However, there is no study investigating this phenomenon in a pediatric population. Understanding risk factors for PCL injuries among a pediatric population is important given the recent rise in athletic competition/specialization and sports-related injuries. HYPOTHESIS/PURPOSE: The purpose of this study was to compare PTSA between pediatric patients sustaining a primary PCL tear compared with age- and sex-matched controls. It was hypothesized that pediatric patients sustaining a PCL tear would have a decreased PTSA compared with controls, with decreased PTSA being associated with higher odds of PCL injury. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: The records of all patients sustaining a PCL injury between 2006 and 2021 at a level 1 pediatric trauma center were reviewed. Patients aged ≤18 years with magnetic resonance imaging-confirmed PCL tear were included. Excluded were patients with concomitant anterior cruciate ligament tears, previous PCL reconstruction, or previous coronal plane realignment. A control cohort, with their ligament shown as intact on magnetic resonance imaging scans, was matched based on age and sex. PTSA was measured on lateral radiographs of the injured knee or tibia. The mean PTSA was compared between cohorts, and odds ratios were calculated based on the normal slope range (7°-10°) described in the literature, an upper range (>10°), and a lower range (<7°). Inter- and intrarater reliability were determined via calculation of an intraclass correlation coefficient. RESULTS: Of the 98 patients who sustained a PCL injury in this study period, 59 (60%) met inclusion criteria, and 59 healthy knee controls were matched. There were no differences between the cohorts for age (P = .90), sex (P > .99), or body mass index (P = .74). The PCL cohort had a lower mean ± SD PTSA compared with the control group (5.9°± 2.7° vs 7.3°± 4.3°; P = .03). PTSA <7° was associated with a 2.8 (95% CI, 1.3-6.0; P = .01) times risk of PCL tear. Conversely, PTSA >10° was associated with a 0.27 (95% CI, 0.09-0.81; P = .02) times risk of PCL tear. These PTSA measurements demonstrated acceptable intrarater and interrater reliability. CONCLUSION: PTSA <7° was associated with an increased odds of PCL injury, whereas a slope >10° was associated with a decreased odds of PCL injury in a pediatric population. These findings corroborate similar outcomes in adult studies; however, further studies are needed to elucidate PTSA as a risk factor for PCL injury.

Change in Posterior Tibial Slope Angle After Displaced Pediatric Tibial Tubercle Fracture: A Model for Growth Modulation in the ACL-Deficient Knee.

Background: Increased posterior tibial slope angle (PTSA) has been shown to be an important risk factor for anterior cruciate ligament (ACL) injury. PTSA modulation is not utilized routinely to reduce risk of primary rupture or graft failure. Displaced tibial tubercle (TT) fractures in the skeletally immature are associated with potential growth arrest and may be used as a model to study PTSA changes in this setting. Purpose/Hypothesis: To quantify the change in PTSA (ΔPTSA) after operative treatment of displaced TT fractures in skeletally immature patients. It was hypothesized that there would be a progressive decrease in PTSA after TT injury and that rate of ΔPTSA would be highest during peak growth velocity. Study Design: Case series; Level of evidence, 4. Methods: Included were 22 patients (n = 23 knees; mean chronological and bone age at injury, 14 years; 86% male) who underwent surgery for displaced TT fracture. PTSA was measured on lateral radiographs at time of surgery and subsequent follow-up, and bone age at the time of injury was determined using radiographic standards. The rate of ΔPTSA for individual patient, total cohort, and sex-based subgroup trends were determined via linear regression (degrees per month; positive value indicates relatively anterior). Individual patient regression coefficients were averaged into bone age cohorts. Results: Average follow-up was 17 months (range, 6-52 months). The mean PTSA was -12°± 2.4° at the time of injury, and the mean ΔPTSA for the cohort was 0.30°± 0.31° per month (range, -0.27° to 0.97° per month). Linear regression demonstrated a significant relationship between months postfixation and PTSA, demonstrating a ΔPTSA of 0.31° per month (95% confidence interval [CI], 0.24° to 0.38°; P < .001). The highest ΔPTSA was seen at bone age 14 years (mean, 0.58°± 0.44° per month). The mean absolute change in PTSA from injury to final follow-up was 4.1° (range, -3.4° to 21°). Conclusion: Our data suggested that PTSA becomes more anterior after operatively treated pediatric TT fractures and that ΔPTSA may be influenced by bone age. This concept may be useful in considering surgical modulation of excessive PTSA in the pediatric ACL-deficient knee.

Allograft Anterior Cruciate Ligament Reconstruction in Adolescent Patients May Result in Acceptable Graft Failure Rate in Nonpivoting Sports Athletes.

BACKGROUND: Studies have demonstrated that pediatric patients have an increased risk of failure with allograft anterior cruciate ligament reconstruction (ACLR); however, there is no study investigating whether allograft ACLR may be safe in older adolescent patients who are not returning to competitive pivoting sports (ie, low risk). The purpose of this study was to assess outcomes for low-risk older adolescents selected for allograft ACLR. METHODS: We performed a retrospective chart review of patients younger than 18 years who received a bone-patellar-tendon-bone allograft or autograft ACLR by a single orthopaedic surgeon from 2012 to 2020. Patients were offered allograft ACLR if they did not intend to return to pivoting sports for 1 year. The autograft cohort was matched 1:1 based on age, sex, and follow-up. Patients were excluded for skeletal immaturity, multiligamentous injury, prior ipsilateral ACLR, or concomitant realignment procedure. Patients were contacted to obtain patient-reported outcomes at ≥2 years follow-up, including single assessment numerical evaluation, surgery satisfaction, pain scores, Tegner Activity Scale, and the Lysholm Knee Scoring Scale. Parametric and nonparametric tests were used as appropriate. RESULTS: Of the 68 allografts, 40 (59%) met inclusion and 28 (70%) were contacted. Among the 456 autografts, 40 (8.7%) were matched and 26 (65%) were contacted. Two allograft patients (2/40; 5%) failed at a median (interquartile range) follow-up of 36 (12, 60) months. There were 0/40 failures in the autograft cohort and 13/456 (2.9%) among the overall autografts; neither were significantly different from the allograft failure rate (both P > 0.05). Two (5.0%) patients in the autograft cohort required manipulation under anesthesia and arthroscopic lysis of adhesions. There were no significant differences between cohorts for single assessment numerical evaluation, Lysholm, Tegner, pain, and satisfaction scores (all P > 0.05). CONCLUSIONS: Although ACL allograft failure rates remain nearly two times higher than autograft failure rates in older adolescents, our study suggests that careful patient selection can potentially bring this failure rate down to an acceptable level. LEVEL OF EVIDENCE: Level III; retrospective matched cohort study.

Nonoperative Management of Femoroacetabular Impingement in Adolescents: Clinical Outcomes at a Mean of 5 Years: A Prospective Study.

BACKGROUND: There is a lack of midterm or long-term outcome data on nonoperative management of femoroacetabular impingement (FAI) syndrome in adolescents despite expanding research mostly focused on arthroscopic management. PURPOSE: To present 5-year outcome data utilizing a nonoperative protocol on a consecutive series of patients presenting to our clinic with FAI syndrome. STUDY DESIGN: Cohort study, Level of evidence, 2. METHODS: A total of 100 patients (62% female; mean age 15 years) who presented to the clinic for evaluation of hip pain and had at least 1 hip with a positive impingement sign were prospectively recruited. The management protocol consisted of an initial trial of rest, physical therapy, and activity modification. Patients who remained symptomatic were offered an intra-articular steroid injection. Patients with recurrent symptoms were then offered arthroscopic treatment. Patient-reported outcomes (PROs), including the modified Harris Hip Score (mHHS) and the Nonarthritic Hip Score (NAHS) were then collected at a mean 1, 2, and 5 years after the initial evaluation. RESULTS: At enrollment, the mean mHHS and NAHS were 69.6 ± 12.9 and 75.5 ± 15.2, respectively. A total of 51 patients (n = 69 hips) were available at a mean 5-year follow-up, with the mean mHHS and NAHS of 89.5 ± 10.8 and 88.1 ± 12, respectively. There was no significant difference in the mHHS or the NAHS between activity modification and physical therapy, injection, or arthroscopic surgery groups at 5-year follow-up (P > .6) and no difference in the proportion of hips meeting the minimal clinically important difference (MCID) for the mHHS based on treatment course (P = .99). There was no significant difference in the mHHS or the NAHS between FAI types at any time point, or in the proportion of hips that met the MCID among FAI types (P = .64). Also, 11 out of 12 hips that required surgery had surgery in less than 2 years. One hip underwent surgery at 5 years after the initial visit. There was no significant drop-off in the mHHS or the NAHS between the 2-year and 5-year time periods (P > .3). CONCLUSION: Nonoperative management of FAI syndrome is effective in a majority of adolescent patients, with significant improvements in PROs persisting at a mean 5-year follow-up.

Skeletal muscle fiber-type specific succinate dehydrogenase activity in cerebral palsy.

INTRODUCTION: Children with cerebral palsy (CP) exhibit increased energy expenditure during movement, but whether this is due in part to decrements in skeletal muscle mitochondrial oxidative capacity is unknown. Accordingly, we compared fiber-type specific succinate dehydrogenase (SDH) activity in children with CP with typically developing (TD) children. METHODS: SDH activity and myofiber areas of type 1 and 2A fibers were measured in semitendinosus biopsies of both groups (n = 5/group). RESULTS: SDH activity was ∼35% higher in type 1 compared with type 2A fibers, but there were no differences between groups. Average myofiber area was 45% smaller in CP versus TD (P < 0.05), and type 2A fibers were 32% larger than type 1 fibers (P < 0.05) only in TD children. CONCLUSIONS: Fiber-type specific SDH activity is similar between TD children and children with CP. This suggests that increased energy expenditure in children with CP is not related to impaired mitochondrial oxidative capacity. Muscle Nerve, 2016 Muscle Nerve 55: 122-124, 2017.