To investigate the accuracy of reconstructing the affected hip joint using the anatomical parameters of the contralateral which is a relatively normal hip joint as a template in total hip arthroplasty (THA).

Patients who underwent their first unilateral total hip arthroplasty at the Joint Surgery Department of the First Affiliated Hospital of Dalian Medical University from September 2019 to December 2020 were selected. Inclusion criteria: diagnosed with hip osteoarthritis (OA), osteonecrosis of the femoral head (ONFH), or developmental dysplasia of the hips (DDH) Crowe type I; the morphology of the contralateral hip joint does not affect its measurement. Exclusion criteria: surgery history on the affected side; severe deformities affecting measurement; DDH Crowe Ⅱ and above. A total of 82 patients were finally included, 33 males and 49 females, ranging in age from 29 to 74. According to the patient’s X-ray and CT image data, the affected and contralateral acetabular anteversion angle, acetabular abduction angle, femoral anteversion angle, neck-shaft angle, and femoral offset were measured, and the combined anteversion angle was calculated respectively.The symmetry of bilateral hip anatomical parameters were analyze by t test and Pearson correlation analysis.

For the patients with ONFH and OA, there was no statistically significant difference in acetabular anteversion angle, acetabular abduction angle, femoral anteversion angle, combined anteversion angle, or neck-shaft angle(all P>0.05), while femoral offset was smaller on the affected side than that on the contralateral side (t=0.523, P<0.05). Pearson analysis showed that asymmetry in femoral offset correlated with neck-shaft angle (r =-0.519, P<0.001), asymmetry in neck-shaft angle correlated with femoral anteversion angle (r=0.303, P=0.041) and femoral offset; and asymmetry combined with anteversion angle correlated with acetabular abduction angle (r=0.311, P=0.035) and neck-shaft angle (r=0.049, P=0.032) in the patients with ONFH or OA. For the patients with DDH Crowe type I, there was no statistically significant difference in acetabular abduction angle, femoral anteversion angle, or combined anteversion angle (all P>0.05), while acetabular anteversion angle (t=2.081, P=0.045) and femoral offset (t=3.934, P<0.001) were smaller on the affected side than that on the contralateral side, neck-shaft angle was greater on the affected side than that on the contralateral side (t=3.792, P=0.001). Pearson analysis showed that asymmetry in femoral offset correlated with neck-shaft angle (r =-0.709, P < 0.001) and femoral anteversion angle (r=-0.349, P=0.037). The femoral offset in the patients with DDH Crowe type Ⅰ was smaller than that in the patients with ONFH or OA, while the acetabular anteversion angle, acetabular abduction angle and neck-shaft angle were greater.

It is feasible to use the contralateral limb as a template to reconstruct the affected hip for the patients with ONFH and OA. The anatomical morphology of the bilateral hip joints in patients with DDH Crowe type Ⅰ is quite different, and total hip replacement surgery for these patients need to be individualized.