Background  Extended trochanteric osteotomy (ETO) is a surgical technique which is widely applied for revision total hip arthroplasty (rTHA). It facilitates the removal of femoral prosthesis or cement in a safe and efficient approach for surgeons, but there are still functional defects for some patients with ETO. Few studies are performed focusing on the clinical outcomes of patients with ETO for rTHA recently.

  Objective  To evaluate the clinical outcomes of the ETO applied for rTHA in a middle-term follow-up.

  Methods  From January 2008 to October 2020, clinical data about patients who underwent ETO in rTHA in the First Medical Center of Chinese PLA General Hospital were retrospectively analyzed in this study. The clinical results, including the Harris hip score and visual analogue scale, before and after the operation and the radiographic results between the affected hip and the normal hip were compared. The union rate of ETO, the migration of osteotomy fragment and the gait with influencing factors were recorded and analyzed.

  Results   Totally 66 patients (66 hips) were included in this study. There were 31 males and 35 females with the mean age of 58.68 years old. There were 27 cases of the left hip and 39 cases of the right hip. The mean time from primary hip arthroplasty to revision was 11.89 years. The causes of revisions included aseptic loosening in 43 cases, periprosthetic fracture in 11 cases, prosthetic joint infection in 9 cases, and dislocation in 3 cases. The femoral defects included Paprosky typeⅠin 10 cases, type Ⅱ in 29 cases, type ⅢA in 22 cases, type ⅢB in 5 cases, and type Ⅳ in 0. The mean operation time for rTHA was 234.19 min, and the mean intraoperative blood loss was 1001.52 mL. The mean length of ETO was 12.84 cm, and then mean follow-up duration was 71.65 months. At last follow-up, there was no statistical difference in abductor lever arm between the affected hip and the normal hip (P=0.507), while both body weight lever arm and greater trochanter-anterior superior spine distance in the affected hip showed significant decrease compared with the normal hip (P=0.012; P=0.005). The Harris hip score increased from (33.70±11.11) points to (83.02±5.23) points (P<0.001), and the visual analogue scale decreased from 8 points to 1 points (P<0.001). At last follow-up, all prostheses were in stable positions with bone ingrowth, and no loosening or fragment migration was observed. There was a limping in 69.7% of all patients, 84.8% of patients showed “very satisfactory” or “satisfactory” in the test of subjective satisfaction. Multiple logistic regression analysis showed that the use of claw-plate fixation for ETO was associated with the lower incidence of moderate-to-severe limping after the operation compared with the cable-alone fixation (OR=0.161, 95% CI: 0.035-0.741).

  Conclusion  Satisfactory outcomes in terms of functional recovery and radiographic evaluation could be achieved in patients undergoing ETO for rTHA, and the claw-plate fixation for ETO have a positive effect on the improvement of gait.