[Effectiveness evaluation of prosthetic revision for aseptic loosening in oncology prosthesis]

To evaluate the effectiveness of prosthetic revision using custom-made long stem prosthesis and allograft-prosthesis composite (APC) for aseptic loosening after bone tumor resection.

Between January 2002 and June 2008, 14 patients with aseptic loosening after bone tumor resection were treated. There were 8 males and 6 females, aged 21-70 years (mean, 43.9 years). The locations were distal femur (8 cases), proximal femur (2 cases), and proximal tibia (4 cases). Pain of the affected limb occurred after 6-31 years of prosthesis replacement and worsened when bearing and walking; 6 patients had shortened limb. The functional results were assessed quantitatively according to the functional rating system of the Musculoskeletal Tumor Society (MSTS). The MSTS score was 16.36 +/- 1.50 before revision. The X-ray films showed obvious prosthetic loosening and subsidence. The average time of symptom was 4.5 years (range, 3-9 years). In 7 patients having severe bone loss (the decrease of the thickness of cortical bone was more than 50%) and the prosthetic subsidence was more than 2 cm, the revision operation with the APC was performed; in 7 patients having less bone loss (the decrease of the thickness of cortical bone was less than 50%), the custom-made long stem prosthesis was performed.

All wound healed by first intention. Two patients had temporary peroneal nerve paralysis and recovered after 3 months. All the patients were followed up 3.6 years on average (range, 2 years and 2 months- 7 years) after revision. After revision, pain was relieved and the range of joint was improved. The MSTS score was 23.43 +/- 2.56 at 12 months after revision showing significant difference when compared with the preoperative score (t = 8.910, P = 0.024). The X-ray films showed that lucency space line around stem cement in 2 patients at 12 months, and no prosthesis loosening and infection occurred.

The prosthetic revision after limb salvage surgery with prosthesis for bone tumors was acceptable. The good functional results can be achieved by the revision with the APC or the custom-made long stem prosthesis according to the bone loss.