ABSTRACT
Recently, cases of hemiarthroplasty that need revision to total hip replacement are increasing. Was to find a classification for expectation of surgical difficulties; moreover the results of follow up of at least 36 months for 32 cases were evaluated. Six males and 26 females of painful aseptic failure of hemiarthroplasties were included. Patients were evaluated both clinically and radiologically. Operative data were recorded and analyzed. Patients were re-evaluated during and after the period of the follow up [with a mean of 49 +/- 8.3 months]. The failed cases of hemiarthroplasty were classified into: Type I: This type includes cases of loose endo-prothesis with a normal or nearly normal acetabulum. It is subclssified into 3 subtypes: I-a: with thin eroded but intact calcar; this was represented by 2 cases. Subtype I-b: calcar eroded till the level of lesser trochanter [18 cases] I-c: lesser trochanter also eroded [5 cases] Type II: Well fixed endoprothesis but eroded acetabulum. This type include 4 cases, mostly of Thompson type [3 cases] Type III: Dislocated hemiarthroplasty. This was subdivided into 2 subtypes. Three cases were included. Type IV: fractures of the femur around the prosthesis. No cases were included in this study. By the end of follow up Harris hip score had increased from a mean of 30.31 preoperatively to 73,59. Only 4 patients were not satisfied. Main complications include: dislocation, wound complication, non union of trochanteric osteotomy, osteolysis and fracture of the femur, thromboembolic complications. Main conclusions: Total hip replacement following aseptic failure of hemiarthroplasty gives commonly high percent of good results and patient's satisfaction. Difficulties during surgery are many. A classification was put to expect these difficulties and for better preoperative planning