Total Hip Arthroplasty for Ankylosing Spondylitis Involving Hip Joint

  Objective  The aim was to evaluate the clinical efficacy of total hip arthroplasty(THA) in the treatment of ankylosing spondylitis(AS) involving hip joint.

  Methods  A retrospective analysis of 23 patients(30 hips) with AS undergoing THA during the period from July 2015 to August 2016 was performed in the department of Joint Suegery, Changhai Hospital, Shanghai. All patients were male, with a mean age of (42.2±12.9)years(ranging from 23 to 65 years). The mean disease duration was (20.2±8.4)years(ranging from 5 to 46 years), and the mean body mass index was (21.6±3.7)kg/m²(ranging from 16.4 to 30.1 kg/m²). For all patients, a posterolateral approach was used to implant the biological prosthesis. The BASFI questionnaire was used to assess the AS functional status. Harris hip scoring system was applied to evaluate the clinical results. The range of motion(ROM) of the hip, BASFI score, and Harris score were compared pre- and post-operatively.

  Results   All patients were followed up for an average of (15.1±3.2)months(ranging from 10 to 21 months); and the hip function was improved markedly after surgery. At the final follow up, the flexion-extension ROM of the hip improved from (44.3±39.6)° to (93.2±19.7)°; the total ROM improved from (64.8±54.8)° to (179.5±25.1)°; the mean value of Harris hip score improved from 39.2±17.2 to 87.5±4.5, with 10 cases rated as excellent and 19 cases as good(the rate of excellent or good result was 96.7%); the mean value of BASFI score decreased from 6.4±2.3 to 2.2±0.9. These differences were all statistically significant(P < 0.001). At the final follow up, all of the locations of the prosthesis were evaluated with X-ray, which showed no signs of aseptic loosening and dislocation of the hip prosthesis. According to Brooker grading system, only 2 hips were classified as GradeⅠ, and no hips were classified as GradeⅡ, Ⅲ, or Ⅳ.

  Conclusion  THA is an effective method in treating AS involving the hip joint to relieve unbearable pains and reconstruct the hip function, which can greatly improve the life quality of AS patients.