Document Type : Original Article
Authors
1
Trauma Research Center, Clinical Sciences Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
2
Artificial Intelligence in Health Research Center, Biomedicine Technologies Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
10.30491/tm.2026.589168.1953
Abstract
Introduction: Total hip arthroplasty (THA) is widely performed for various hip disorders, including post‑traumatic conditions. However, its effect on coronal lower limb alignment remains debated, and data on early postoperative alignment changes are limited. This registry‑based study aimed to evaluate changes in lower extremity alignment following THA in patients with traumatic and other hip disorders.
Method: A consecutive series of 40 patients (40 hips) who underwent primary THA between March 2025 and March 2026 was included. Bilateral standing full‑leg radiographs were obtained preoperatively and two months postoperatively. Radiographic parameters measured included lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), hip‑knee‑ankle angle (HKA), joint line convergence angle (JLCA), and mechanical femorotibial angle (mFTA).
Result: The cohort comprised 23 males and 17 females, with a mean age of 63 ± 12 years. On the operated side, no significant changes were observed for LDFA (89.9° ± 3.4° to 89.3° ± 3.5°, p = 0.203), MPTA (86.7° ± 3.0° to 87.0° ± 3.1°, p = 0.008), HKA ( 3.2° ± 5.2° to 2.4° ± 5.0°, p = 0.121), JLCA (1.8° ± 2.3° to 2.2° ± 2.8°, p = 0.222), or mFTA (5.1° ± 5.8° to 4.5° ± 5.7°, p = 0.788). On the contralateral side, none of the parameters changed significantly (all p > 0.05). Subgroup analysis by trauma history showed small but statistically significant differences in LDFA (p = 0.034) and MPTA (p = 0.010) changes on the operated side, though overall limb alignment parameters remained stable.
Conclusion: At two months after THA, coronal lower limb alignment remained stable on both the operated and contralateral sides in this predominantly non-traumatic cohort. These radiographic findings indicate that THA does not induce clinically meaningful early alterations in coronal lower limb alignment, as measured on standing full-leg radiographs. However, this study did not assess clinical outcomes such as pain, function, gait, or patient-reported outcomes, and no conclusions can be drawn regarding the clinical significance of the observed alignment stability or the need for routine early follow-up. Furthermore, the findings are limited to the early postoperative period; longer follow‑up is essential to assess potential late changes and their clinical implications.
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