The presented case study aimed to evaluate changes in a femoral rotation after Total Hip Arthroplasty and to investigate preoperative patient factors that influence femoral rotation after THA. This study was approved by the authors’ institutional review board of Yokohama City University and informed consent was obtained from all patients. The inclusion criteria for this study were as follows: hips treated with THA between 2008 and 2013, and patients whose hips were examined using with computed tomography (CT) before and one week after THA and achieved a total of 299 hips met the inclusion criteria. Exclusion criteria included a hip flexion contracture of more than 10° and absence of CT imaging from the anterior superior iliac spine (ASIS) to the femoral condyles. Some additional notes about the patients who carried this study out:
The result has shown that no patients had complaints one week after surgery except pain originating from the incision screw and there were no symptoms of impingement or gait abnormalities that could be clearly associated with excessive femoral rotation. Also a week after the surgery, the study shows that the mean internal change of 4.6° in the femoral rotation angle. There was no significant difference in femoral rotation between groups treated with a mini-direct lateral approach and with an anterolateral approach.
All patients were capable to walk independently with or without a cane and were discharged from the hospital at 10 days after THA.
At one year after surgery, there were no complaints of gait abnormalities. No dislocations were observed throughout the study period.
The mean preoperative femoral rotation was 0.2 ± 14° and the mean postoperative femoral rotation was − 4.4 ± 12° (p < 0.001). Among 211 out of 299 examined hips reached the following conclusions:
– 88 hips were identified with internally rotated femurs before and after THA;
– 43 hips had femurs rotated externally before THA and internally after THA;
– 20 hips showed femoral internal rotation before THA and external rotation after THA;
– 53 hips demonstrated femurs rotated externally before and after THA;
– 7 hips revealed the femoral rotation angel more than 20 ° before THA.
There were no complaints of gait abnormalities. No dislocations were observed throughout the study period. There was no significant difference between groups treated with a mini-direct lateral approach and treated with an anterolateral approach. Sex, age, preoperative anatomical femoral anteversion and preoperative femoral rotation angle were significant predictors for the postoperative femoral rotation angle in the supine position.