Morphological changes affecting ipsilateral and contralateral leg alignment after total hip arthroplasty.

Area of Science:

• Orthopedic surgery
• Biomechanical analysis
• Radiographic assessment

Background:

• The relationship between hip morphology and leg alignment variations remains unclear.
• Investigating the role of morphological changes in hip disorders is crucial.
• Understanding these factors is essential for predicting post-operative outcomes.

Purpose of the Study:

• To analyze leg alignment changes after total hip arthroplasty (THA).
• To identify morphological factors influencing ipsilateral and contralateral leg alignment post-THA.

Main Methods:

• Retrospective cohort study of 100 patients undergoing THA.
• Bilateral standing whole-leg radiographs (pre- and post-operative) were analyzed.
• Key measurements included hip-knee-ankle angle (HKAA), joint line convergence angle (JLCA), hip center height, lateral width, femoral offset, and leg length discrepancy.

Main Results:

• A mean varus HKAA change of 0.8° was observed on the THA side, correlating with JLCA change.
• Ipsilateral valgus alignment correlated with medial hip center shift and varus HKAA change.
• Contralateral valgus or neutral alignment correlated leg length discrepancy changes with varus HKAA change.

Conclusions:

• Medial hip center shift significantly impacts ipsilateral leg alignment post-THA.
• Changes in leg length discrepancy are significant for contralateral leg alignment after THA.