Outcomes after Total Hip Arthroplasty Using a Cementless S-ROM Modular Stem for Patients with High Hip Dislocation Secondary to Hip Pyogenic Arthritis.

Objective: To evaluate the midterm results of the cementless S-ROM modular femoral stem used with subtrochanteric transverse shortening osteotomy for the treatment of high hip dislocation secondary to hip pyogenic arthritis.

Methods: We retrospectively reviewed the data of 49 patients (49 hips) with an average infection quiescent period of 37.4 years who underwent cementless total hip arthroplasty (THA) with simultaneous subtrochanteric transverse shortening osteotomy from July 2008 to June 2012. There were 23 men and 26 women with a mean age of 44.3 years at the time of surgery. The following clinical outcomes were evaluated: the Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, Harris hip score (HSS), modified Merle d'Aubigne-Postel hip (MAP) score, low back pain visual analog scale score, 12-item short-form health survey questionnaire score, limp, and Trendelenburg sign. Radiographic outcomes and complications were also evaluated.

Results: The mean follow-up period was 8.7 years (range, 5.5-10 years). No infection recurrence was observed after THA. The average HSS significantly improved from 45.0 to 84.8. The WOMAC score improved from 70.1 ± 3.5 (range, 65-76) to 43.1 ± 13.4 (range, 21-67). The modified MAP score improved from 5.9 ± 1.9 (range, 3-9) to 14.3 ± 2.4 (range, 11-18). The low back pain visual analog scale score, 12-item short-form health survey questionnaire score, limp, and Trendelenburg sign also improved significantly. The average limb length discrepancy decreased from 39.6 mm (range, 30-55 mm) to 7.2 mm (range, 0-22 mm). Two patients had temporary sciatic nerve paralysis but recovered within 6 months without any functional defects; one had an intraoperative fracture fixed by cerclage wires. One hip required revision surgery because of femoral stem aseptic loosening.

Conclusions: The cementless S-ROM modular femoral stem used with subtrochanteric transverse shortening osteotomy is safe and effective for high hip dislocation secondary to pyogenic arthritis and provides satisfactory midterm results. Significant improvements in clinical function were observed, as were high rates of stable fixation of the cementless implant, restoration of more normal limb lengths, and a low incidence of complications.