Clinical and radiological outcomes of changes in the lower extremity and spine following total hip arthroplasty in patients with unilateral Crowe Type III and Crowe Type IV hip dysplasia

Objective: To demonstrate the clinical and radiological outcomes of changes in the lower extremities and spine in patients with unilateral Crowe type 3 and type 4 hip dysplasia following total hip arthroplasty in the short term. Materials and Methods: Patients with Crowe type 3 and type 4 hip dysplasia were prospectively evaluated in the Department of Orthopedics and Traumatology at Bezmialem Vakıf University Faculty of Medicine. The study was registered in ClinicalTrials prior to its commencement. In addition to demographic and surgical characteristics, preoperative and postoperative assessments at the 1-year follow-up included standing anteroposterior pelvis radiographs, standing anteroposterior leg length radiographs, and standing and sitting anteroposterior and lateral lumbosacral radiographs. Harris Hip Score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form 12 (SF-12) Quality of Life Scale, Kujala Patellofemoral Pain Score, Oxford Knee Score, Oswestry Disability Index (ODI), Roland Morris Disability Questionnaire, American Orthopedic Foot-and-Ankle Society Ankle-Hindfoot Score (AOFAS), and Foot and Ankle Disability Index (FADI) scores were all collected and evaluated. Results: A total of 33 patients with a mean age of 52.70±11.83 years were included in the study. The average follow-up period was 18.27±7.04 months. Among these, 13 patients (39.3%) had Crowe type 3 and 20 patients (60.6%) had Crowe type 4 hip dysplasia. Significant postoperative improvements were observed in HHS (ipsilateral side, p<0.001), WOMAC (ipsilateral side, p<0.001), HHS (contralateral side, p=0.001), WOMAC (contralateral side, p=0.003), SF-12 scores (p<0.001), ODI (p=0.014), Roland Morris Disability Questionnaire (p=0.004), and WOMAC knee score (ipsilateral side, p=0.038). Radiological measurements showed a significant reduction in the Mean Acetabular Deformity (MAD) on the ipsilateral side (p<0.001), a significant reduction in leg length discrepancy (p<0.001), a significant increase in the Joint Line Congruency Angle (JLCA) on the ipsilateral side (p=0.024), a significant increase in the Acetabular Joint Line Orientation (AJLO) on the ipsilateral side (p=0.049), a significant increase in Sacral Slope (SS) (p=0.027), and a significant reduction in Lumbosacral Lordosis Angle (LLA) (p<0.001) on the ipsilateral side. Conclusion: In the short-term results of our cases, consistent with the literature, the alignment of the lower extremities showed that preoperatively, the operated side had a valgus alignment of the knee and the contralateral side had varus alignment. Postoperatively, valgus alignment on the operated side decreased but did not return to neutral, while varus alignment on the contralateral side remained unchanged. When assessing spinopelvic parameters, Sacral Slope (SS) remained within normal preoperative and postoperative limits and showed a statistically significant increase. Lumbosacral Lordosis Angle (LLA) remained within normal limits preoperatively and postoperatively, but was statistically significantly lower postoperatively. Furthermore, significant postoperative improvement was observed in hip scores, SF-12, lumbar scores, and WOMAC knee score on the ipsilateral side. Keywords: adult hip dysplasia, Crowe type 3, Crowe type 4, total hip arthroplasty, subtrochanteric femoral shortening osteotomy