Letter to the Editor: Spinopelvic Alignment and Low Back Pain after Total Hip Replacement Arthroplasty in Patients with Severe Hip Osteoarthritis

Dear Sir,

We have read the article entitled “Spinopelvic alignment and low back pain after total hip replacement arthroplasty in patients with severe hip osteoarthritis” by Eguchi et al. [1] with a lot of interest. First of all, we congratulate the authors for bringing out an important observation related to low back pain and spinopelvic parameters following total hip arthroplasty. However, we note some findings that we would share.

(1) The authors have used an unpaired t-test for various variables which they recorded before and after the hip arthroplasty, which we feel should have been a paired t-test. Since there is a change in the Visual Analog Scale (VAS) scores of hip pain and low back pain at three intervals, i.e., at preoperative, 1 month, and final follow-up, it would be interesting to reanalyze the data using the repeated measure analysis of variance (ANOVA). Finally, if required, a post hoc analysis can be applied after repeated measure ANOVA.

(2) Twelve patients with bilateral hip arthritis were operated by the authors. We believe they were operated unilaterally and not bilaterally. The VAS score in them for low back pain was not reduced as much as for unilateral arthritis. No mention about the coxalgia for the nonoperated side has been done at various time intervals for them.

(3) We also would like to know if the aetiology for total hip arthroplasty like ankylosing spondylitis (AS) and non-AS were evaluated in the author’s study. Overall, the study is impressive and useful.