抄録
Introduction: Replenishing the bone defect is an important factor in revision total hip arthroplasty (THA). Various methods have been used to complement massive bone defects, and recovering the bone stock is an important issue. In this study, we used a large volume of hydroxyapatite (HA) to reconstruct the acetabulum, and examined the postoperative results.
Methods: From the patients who underwent THA at our hospital, 12 patients (12 hips) were selected who suffered from severe pain and whose acetabulum showed a significant amount of bone defect on radiographic analysis. Two patients were men and ten were women; they had a mean age of 63 years (2676). Eleven had osteoarthritis and one had avascular necrosis of the femoral head after traumatic injury. The mean observation period after the revision surgery was 12.8 years. We constructed the acetabulum using a large amount of HA granules and then fixed the cup with cement. In five patients, we also used Kerboull cross plate as the inner layer. Three patients also underwent revision of the femoral side. The JOA score was used for clinical evaluation. A plain anteroposterior radiogram was used for radiographic evaluation. We examined the following three factors: (1) collapse of the HA, (2) conditions of bone formation in the interface of the bone bed and HA, and (3) loosening and displacement of the cup.
Results: The mean JOA score improved from 51 to 67 after the surgery. On radiographic evaluation, bone formation was observed after about 3 months. After approximately 1 year, the interface of the bone and the HA was incorporated. After incorporation, there were no further changes on radiography. Collapse of the HA and displacement of the cup were not observed during 9.3 years of follow-up.
Discussion: When performing revision THA in patients with acetabulum bone defects, autologous bone, HA, allogeneic bone, or Kerboull and a large cup could be used to complement the defects. However, taking into consideration quality, quantity, and infection problems, HA can be effective in massive bone defects. Initial fixation and collapse on load bearing are the conventional concerns when HA alone is used during surgery, but these were not observed in our patients. We believe that using HA is effective for complementing large bone defects.
