A modified porous tantalum implant technique for osteonecrosis of the femoral head: survivorship analysis and prognostic factors for radiographic progression and conversion to total hip arthroplasty.

Tantalum rod implant following core decompression is reported to be effective in early stage of osteonecrosis of the femoral head (ONFH). The purpose of this study was to assess the survivorship and prognostic factors for radiographic progression and conversion to total hip arthroplasty (THA) after treatment with a modified tantalum implant technology. 59 consecutive hips (45 patients) in whom ONFH was treated with core decompression, impaction bone grafting of 2 mm-composite bone filling material, and insertion of a porous tantalum implant. 57 hips (44 patients, mean age 43 years, range 21 to 70 years) with Steinberg Stage I-IVA ONFH were available for follow-up at a mean of 44.8 months (rang, 11 to 62 months). Outcome measures included HHS (Harris Hip Score), radiographic outcome, and survivorship analysis with reversion to THA. Radiographic progression occurred in 17 hips (17/57, 29.82%). 11 hips (11/57, 19.30%) were converted to THA. The overall survival rate was 72.49% at 60 months post-operatively. After logistic regression analysis, corticosteroid use and bone marrow edema were found to be predictors of radiographic progression. The Cox proportional-hazard model revealed that bone marrow edema was an independent prognostic factor for conversion to THA. This modified technology may make patients avoid the use of corticosteroid, especially those without bone marrow edema, and obtains encouraging survival rates and a delay in or prevention of THA.