The Open Triradiate Cartilage: How Young Is Too Young For Total Hip Arthroplasty?

Background: There is, to our knowledge, no published literature regarding primary total hip arthroplasty (THA) in pediatric patients with an open triradiate cartilage. The purpose of this study was to report the outcomes following primary THA in pediatric patients with open triradiate cartilage at a single intuition. Methods: Using a single institution's Total Joint Registry, 12 patients (13 hips) were identified as having undergone primary THA with open triradiate cartilage between the years of 2000 and 2019. The mean age and body mass index of this group were 13.1 years and 25.5 kg/m(2), respectively. The cohort was composed of 10 males, and the mean follow up was 5.5 years. Indications for surgery, functional outcomes, and radiographic signs of stable fixation were analyzed. Results: The most common indication for surgery was avascular necrosis secondary to corticosteroid use (31%), followed by avascular necrosis after operative management of slipped capital femoral epiphysis (23%). The proportion of patients able to achieve independent, gait-aid free, ambulation improved from 23% to 100%. Mean postoperative Harris Hip Score was 92.3. All constructs were cementless, and bearing surfaces included ceramic-on-ceramic in 62% and ceramic on highly crosslinked polyethylene bearings in the remainder. Radiographic review at final follow up demonstrated osseointegration in 12 of 13 (92%) acetabular components. Although 1 patient experienced both acetabular component loosening and instability, on separate occasions, there were no incidences of infection, wound dehiscence, thromboembolic events, or failure secondary to wear. Conclusions: In this study, THA in patients with an open triradiate cartilage yielded significant clinical improvement, low complication rates and good initial implant survivorship at early follow up. Awaiting closure of the triradiate cartilage for concerns of decreased fixation and implant survivorship may be unnecessary.