Purpose: To determine the incidence and the time to failure of repaired short external rotator muscles through aposterolateral approach in total hip arthroplasties; and to describe the correlation between failure of the repaired short external rotator muscles and the hip dislocation rate. Materials and Methods: Between January 2003 and October 2003, 51 patients (55 cases) were treated with primary, uncemented total hip arthroplasties. The average patient`s age was 51 years (33 men, 19 women). After the short external rotator muscles were repaired, two 26-gauge wires were stitched as a marker to the abductor tendons and short external rotator tendons. The distance between the two opposing reference points was less than 1.2 cm. The distance between the markers was determined on radiographs that were obtained 1 day, 2 weeks, and 3 months post-operatively. A distance of more than 2.5 cm, or an invisible one, indicated failure. Results: Of a total of 52 repaired short external rotator muscles, 45 (86.5%) failed. Twenty-five(48.1%) failed within the first day, 15 (28.8%) within 2 weeks, and 5 (9.6%) within 3 months post-operatively. Regardless of the time of failure of the repaired short external rotator muscles, postoperative hip dislocations did not occur. Conclusion: The repair of short external rotator muscles after total hip arthroplasties has a high failure rate and contributes little to the prevention of hip dislocations.