Abstract
Introduction
Patients presenting with osteoarthritis as late sequelae following pediatric hip trauma have few options aside from standard Total Hip Replacement (THR). For younger more active patients, Hip Resurfacing Arthroplasty (HRA) can be offered as an alternative. HRA has been performed in the United States over the past decade and allows increased bone preservation, decreased hip dislocation rates versus THR, and potential to return to full activities.
Patients presenting with end-stage hip arthritis as following prior pediatric trauma or disease often have altered hip morphology making HRA more complicated. Often Legg-Calve-Perthes (LCP) patients present with short, wide femoral necks, and femoral head distortion including coxa magna or coxa plana. There often can be acetabular dysplasia in conjunction with the proximal femoral abnormalities.
Slipped Capital Femoral Epiphysis (SCFE) patients have an alteration of the femoral neck and head alignment, which can make reshaping the femoral head difficult. In particular, the femoral head is rotated medially and posteriorly, reducing the anterior and lateral offset.
We present a cohort of 20 patients, with history of a childhood hip disorder (SCFE or LCP), who underwent HRA to treat end-stage arthritis. Fifty percent had prior pediatric surgical intervention at an average age of 11.
Method
After Institutional Review Board approval, data was reviewed retrospectively on patients with pediatric hip diseases of SCFE and LCP who underwent HRA using the Birmingham Hip Resurfacing (BHR) by a single orthopaedic surgeon at a teaching institution. Harris Hip Scores (HHS), plain radiographs and blood metal ion levels were reviewed at routine intervals (12 months and annually thereafter). Those who had not returned for recent follow-up were contacted via telephone survey for a modified HHS.
Results
Twenty patients had mean follow up of 2.8 years (range 1–7 years). Twelve had LCP and 8 SCFE. Median implant duration was 2.4 years. One-year metal ion testing revealed median chromium level of 2.3 ppb and median Cobalt level of 1.5 ppb. At one-year follow up, plain radiographs demonstrated all patient implants to be well-fixed, without radiolucent lines or osteolysis. Two patients at three and five-year follow-up exhibited heterotopic ossification. Mean HHS for LCP at 6 weeks post-operative was 88, and 98 at one year. Mean HHS for SCFE at 6 weeks post-operative was 77.5, and 98.6 at one year. LLD was significantly improved with an average pre-operative LLD of 12.6 mm and post op of 2.6 mm (p-value <0.001). At most recent follow-up, all retained their implants with overall average HHS of 98.
Conclusion
At minimum of one-year following HRA, an increase in functional outcomes is found in patients who underwent HRA for osteoarthritis associated with LCP and SCFE with a mean HHS of 98. No increase was found in complications including femoral neck fracture or implant loosening despite technical challenges of the procedure related to proximal femoral morphologic abnormalities, or presence of acetabular dysplasia [Fig 1].
