QUANTITATIVE MEASUREMENT OF JOINT SPACE NARROWING PROGRESSION IN HIP OSTEOARTHRITIS - A LONGITUDINAL RETROSPECTIVE STUDY OF PATIENTS TREATED BY TOTAL HIP-ARTHROPLASTY

Objectives. To evaluate the rate of progression of radiological joint space narrowing (JSN) in patients operated on for hip osteoarthritis ( OA) and to determine its predictive factors. Methods. Study design: re trospective longitudinal trial of 61 patients who underwent total hip arthroplasty (THA) for hip OA (69 operated hips). Mean follow-up 81.2 +/- 9.9 months. Collected data: (1) standing frontal radiographs of th e pelvis from diagnosis to surgery (246 films) for morphological evalu ation and quantitative measurement of joint space width (JSW) (compute rized reading of digitized X-rays); (2) demographic data (sex, age, bo dy mass index, smoking status, professional and sporting activities, f amily history of GA); (3) clinical data (age at onset-diagnosis and TH A, drug consumption, time from diagnosis to permanent disability, OA a t other joints, previous THA of the contralateral hip). Statistics: mu ltivariate analysis. Results. The yearly mean narrowing (YMN) of MeanJ SW was 0.43 +/- 0.43 mm/yr (median 0.29, range 0.03-2.55). YMN correla ted inversely with joint space width at operation and follow-up durati on, and was increased in atrophic OA (r = 0.71). The time between diag nosis and THE correlated with JSW at diagnosis, and was inversely corr elated with age at onset and YMN. It was longer in patients with hyper trophic OA (r = 0.69). Conclusion. Rapid progression of JSN, older age and absence of osteophytes appear to be the main factors leading to T HA.