Evaluation of Differences Excepting the Morphology of the Hip Joint Between Primary and Secondary Hip Osteoarthritis due to Dysplasia

Abstract

Objective: To evaluate the differences excepting the morphology of the hip joint between primary and secondary hip osteoarthritis (OA) due to dysplasia.

Methods: Eighteen primary and 50 secondary hip osteoarthritis due to dysplasia were examined. Laboratory studies and dual X-ray absorptiometry were performed. The number of spinal bodies bridged by intervertebral osteophytes were counted in the lumber spinal radiograph according to Resnick’s criteria of diffuse idiopathic skeletal hyperostosis (DISH). The sum of the length of bilateral enthesophytes in the iliac crest and the degree of sacroiliac joint degeneration were evaluated by pelvic computed tomography.

Results: The mean age of primary and secondary OA was 76 and 63 years old, respectively. The occurrence of primary OA was found in a significantly older age group than secondary OA. The primary OA patients had significantly higher levels of leucocytes, fasting blood sugar (FBS), and fibrinogen than patients with secondary OA. There was an increasing number of spinal bodies with DISH in patients with primary OA. Despite the absence of statistical significance, the patients with primary OA tended to have higher body mass index (BMI), alkaline phosphatase, erythrocyte sedimentation rate, and C-reactive protein. In patients with primary OA, bilateral enthesophytes in the iliac crest tended to be longer, and the degree of sacroiliac joint degeneration tended to be higher.

Conclusions: Advanced age, higher levels of FBS and BMI in patients with primary OA in this study supports a previous report that aging and the metabolic syndrome lead to low-grade systemic inflammation in OA. There may be cases with this OA subtype as a phenotype of DISH in patients who present with primary OA.