OBJECTIVETo analyze the intermediate-term results associated with the use of Zweymtiller hip system.

METHODSReview the 116 cases (142 hips) who were treated with total hip replacement from 1996 to 2002 by a single surgeon using cementless Zweymüller hip systems.

RESULTSSixty-one cases (77 hips) were followed up, 50 cases (64 hips) were evaluated both clinically and radiographically while 5 cases (6 hips) and 6 cases (7 hips) were only evaluated clinically and radiographically respectively. The average follow-up period was 7.3 years (range 5 to 11 years). The mean preoperative Harris Hip Score was 46 while the mean postoperative Harris Hip Score was 93. Distal cortical hypertrophy and medullary sclerosis were observed in 30 hips (42.3%) and 33 hips (46.5%) respectively. Heterotopic ossification arose in 45 hips (63.4%). Radiolucent lines occurred in 27 stems (38.0%) but in no cups. Radiolucent lines were mostly observed in Gruen zones 1. Osteolysis occurred in 7 cups (9.9%) and 18 stems (25.4%). Osteolysis was mostly observed in Delee Zone 3 and Gruen zone 7. In the distal Gruen zones 3, 4 and 5, no radiolucent line or osteolysis was observed. No hips had been revised, 3 cups needed revision surgery because of aseptic loosening.

CONCLUSIONThe 5-11 years follow-up results are satisfactory, but osteolysis is common.