We are truly grateful for the opportunity to respond to this Letter to the Editor concerning our recently published study entitled “Spinopelvic alignment and low back pain after total hip replacement arthroplasty in patients with severe hip osteoarthritis [1].” First, we thank the authors for their interest in our work and for the opportunity to further explain low back pain improvement following total hip arthroplasty (THA) in patients with severe hip osteoarthritis.

(1) We reanalyzed the Visual Analog Scale (VAS) scores for low back pain and coxalgia in patients before and after THA using the repeated measure analysis of variance followed by a post hoc analysis (Bonferroni analysis). VAS scores for low back pain (preoperative, 1-month postoperative, and final observation) were 22.82 mm → 6.0 mm (p =0.0001) → 9.26 mm (p =0.0017), respectively. VAS scores for coxalgia were 63.89 mm → 20.33 mm (p <0.0001) → 4.03 mm (p <0.0001), respectively, which showed significant improvements.

(2) In our study, 12 patients with bilateral hip arthritis were operated on unilaterally. There were no significant improvements in coxalgia from preoperative to final observation in the contralateral side. Their low back pain remained after THA because of hip joint dysfunction and a further decline in the contralateral side.

(3) We have no data about the aetiology for THA like ankylosing spondylitis (AS) and non-AS. These data should be addressed in future studies.