Purpose : To analyse of the result of the treatment of periprosthetic fractures after total knee arthroplasty Materials and Methods: We reviewed 1J knees of 1 1 patients with supracondylar periprosthetic fractures who underwent total knee arthroplasty between July 1989 and October 1998. There are 1 man and 10 women. The average follow-up period was 24 months(Range, 6 - 61). The patients were grouped according to the treatment mothods; Group I is the patients who were treated by cast or cast brace. Group II is the patients who were treated by skeletal traction followed by cast or cast brace. Group III is the patients who were treated by retrograde intramedullary nails, We analysed time required for union, tibiofemoral angle after union, Range of motion and HSS score of each group. Results: Time required for union is shorter in Group I and III than Group II. Tibiofemoral angle after union is not significant change in all Groups postoperatively. ROM was not decreased in Group III but there was significant changes. HSS score was decreased in Group II, 85 preoperatively and 64 postopera-tively. Conclusion: Cast or Cast brace only can be recommended for knees in which the initial alignment and stability of fracture were in acceptab1e range, In knees with malaligned and unstable periprosthetic fracture, retrograde IM nails can be recommended for better clinical and radiological results.