RESUMO
PURPOSE: To analyze the characteristics and causes of periprosthetic huge mass which occur after treatment by total hip arthroplasty. MATERIALS AND METHODS: Of the patients who had undergone total hip arthroplasty from January 2000 to October 2007, we retrospectively evaluated the 10 patients who suffered huge soft tissue mass. Five of these patients had received metal-on-metal bearing (group 1) prostheses, and the other 5 had received metal-on-polyethylene bearings (group 2). We evaluated the size and location of the mass, the extent of osteolysis, and the hematologic and pathologic examination results. RESULTS: Roentgenographically, the location of the masses varied from the acetabular area to the distal femoral stem. The mean mass diameter of all 10 patients was 14.6 cm(7-21 cm)x6.2 cm(3-9 cm)x7.2 cm(4-12 cm). Osteolytic lesions were found in 3 group 1 patients and 3 patients in group 2. High counts of lymphocytes and eosinophils were present in group 1. High counts of macrophages were present in group 2. CONCLUSION: The occurrence of osteolysis and huge soft mass after total hip arthroplasty is thought to be related to foreign body reaction by polyethylene wear particles and metal hypersensitivity. Outside-in patterned cortical thinning was considered to be indicative of a long standing periprosthetic soft tissue mass effect.
