A total joint arthroplasty refers to non-biologic replacement of articulating surfaces of a joint. The positioning of the acetabular component is a crucial step of the surgical technique. The position of the acetabular component in the medial-lateral direction influences offset leading to changes in the moment-lever arm of the abductor musculature. The anteversion of the acetabular cup in the sagittal plane and the inclination angle (also known as abduction angle) in the coronal plane are both important determinants of acetabular position.
The present study was conducted to see the effect of acetabular cup orientation and femoral stem placement on the functional outcome in cementless hip replacement arthroplasty exclusively.
Methodology: The present open-ended retrospective study was conducted in the Department of Orthopaedic Surgery, King George Medical University, Lucknow, UP on patients operated by uncemented total hip arthroplasty from 1st January 2012 to 30th April 2015. The following protocol was followed for every patient: -
Demographic data and clinical examination of enrolled patients was noted.
Functional outcome assessment by calculating the Harris Hip Score
Radiological Evaluation by a standard x-ray of pelvis with both hip-AP (including whole implant)
Statistical tools: Final data was analyzed by SPSS v. 16. Normality of the data described by mean and SD. For comparing variables with normal distribution, paired t-test, independent t-test, and ANOVAs test were used. Qualitative variables were expressed with frequency and percent. A p value of <0.05 was considered statistically significant.
Results: In our study we found that the mean Harris hip score increased from 42.5 points (range 18–69) preoperatively to 94.3 points(range, 82–100) at mean follow up of 2 years (p value-<0.001). Our study showed excellent functional outcome in 31 hips (81.5%) while 7 hips (18.5%) had good functional outcome.
Conclusion: In our study we did not find any effect of femoral stem placement on the functional outcome. Whether the stem is implanted in varus, valgus or neutral alignment, no significant difference was seen in their mean Harris Hip Scores.