Selemon, Nicolas A.

Abstract Introduction The utilization of total hip arthroplasty (THA) in skeletally immature patients remains controversial, with an open triradiate cartilage traditionally perceived as a relative contraindication due to concerns of acetabular fixation and component loosening. Early evidence suggests that THA may be a feasible option in this patient population yielding favorable short-term outcomes, however larger series and mid-term data are lacking. This study presents the largest series of THA in patients with open triradiate cartilage to date with mid-term clinical, radiographic, and patient-reported outcomes. Methods A retrospective review of our institutional Total Joint Registry identified 19 patients (22 hips) who underwent THA while having an open triradiate cartilage growth plate between the year 2000 and 2024. Skeletal maturity was assessed utilizing the modified Oxford bone age and all patients had a score of “1” or “2” on the triradiate cartilage stage of maturation. Demographics, surgical characteristics, implant data, radiographic parameters, and clinical outcomes were collected. Functional hip scores were assessed via the Harris Hip Score (HHS). Kaplan-Meier analysis was performed to analyze reoperation rates. Results The average age at surgery was 14 years (SD=1.68), the average BMI was 24 (SD=7.1) and 64% were male. Mean follow-up was 6.05 years (range 1-15). The mean modified Oxford bone age for this cohort was 23 (SD=1.4). The most common indications for THA were avascular necrosis (64%), degenerative joint disease (27%), and neoplasia (9%). Preoperatively, 54.5% of patients utilized gait aids. Postoperatively, all patients reported independent ambulation without assistive devices with an average HHS of 91.65 (SD=11.42). Ninety-six percent of implants were stable at final radiographic follow up. Both reported complications involved acetabular cup loosening, requiring revision of the acetabular component. Conclusion This study presents the largest cohort in the literature of patients who underwent THA with open triradiate cartilage. Our results highlight high patient reported outcomes and low revision rates at mid-term follow up. All patients had excellent implant fixation without radiographic signs of loosening at final radiographic follow up. These results support the use of THA in skeletally immature patients without the need to delay THA for closure of the triradiate cartilage.

Abstract Osteonecrosis (ON) of the femoral head is a significant complication following chronic corticosteroid treatment, especially in adolescents and young adults. While studies in the adult population suggest that early core decompression augmented with bone marrow aspirate concentrate injection (BMAC) may reduce progression, evidence in younger patients remains scarce. This study evaluates survivorship free from femoral head collapse and conversion to total hip arthroplasty following core decompression with BMAC in patients under 25 years old with corticosteroid-induced femoral head ON. A retrospective review was conducted of 13 patients (24 hips) who underwent hip core decompression with BMAC for corticosteroid-induced femoral head ON. Variables analyzed included sex, body-mass index, age at index surgery, continued corticosteroid use, concomitant labral tear, Kerboul angle/grade, and Steinberg classification of osteonecrosis. These variables were assessed for their association with survivorship free of THA, conversion to THA, and patient reported outcomes (PROs) (modified Harris Hip Score [mHHS] and Hip Disability and Osteoarthritis Outcome Score [HOOS-12]). The mean follow-up duration was 10 ± 5.4 years. At the final follow-up, 11 hips (45.8%) required reoperation, including 10 total hip arthroplasties and one femoral head resurfacing. Progression to radiographic femoral head collapse occurred in 9 hips (37.5%), resulting in a collapse-free survival rate of 62.5%. The mean survival time until reoperation was 8.34 years. Continued corticosteroid use (p=0.033), Steinberg stage >2 (p=0.044), male sex (p=0.045), and high BMI (p=0.002) were associated with increased risk for reoperation. On multivariate analysis, ongoing corticosteroid use (OR=6.4, p=0.01) and Steinberg stage >2 (OR=4.3, p=0.04) were predictors of reoperation. Patient-reported outcomes at final follow-up included a mean mHHS of 77.5 and a HOOS-12 score of 80%. Core decompression with BMAC for corticosteroid induced femoral head ON in adolescents and young adults resulted in collapse-free survival rate of 62.5% at average 10 years follow up with an average reoperation-free survival of 8.34 years. Patients with Steinberg stage ≥2 and ongoing corticosteroid use had high rates of reoperation and conversion to total hip arthroplasty. Our data highlights that careful patient selection and shared decision-making remain critical in optimizing patient outcomes in this challenging patient population.