Horizontal offset variation, correlation with neck shaft angle in primary and complex total hip arthroplasty.

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Radiology

Background:

• Total Hip Arthroplasty (THA) aims to restore hip joint function and biomechanics.
• Individual variations in hip anatomy, such as horizontal offset and neck shaft angle, can impact surgical outcomes.
• Accurate pre-operative assessment is vital for successful THA reconstruction.

Purpose of the Study:

• To evaluate individual variations in horizontal offset and neck shaft angle during pre-operative templating for THA.
• To compare horizontal offset before and after THA.
• To determine the correlation between hip center of rotation restoration, horizontal offset, and hip biomechanics.

Main Methods:

• Pre-operative templating was performed on 150 patients (103 males, 47 females) undergoing unilateral THA.
• Standard AP pelvic radiographs were analyzed using PACS to determine horizontal offset and neck shaft angle.
• Post-operative X-rays were used to assess the restoration of horizontal offset.

Main Results:

• Mean pre-operative horizontal offset was 4.50 cm (range 2.58-7.0 cm) and mean neck shaft angle was 129.4°.
• Post-operative horizontal offset was restored within ±5 mm in 71.4% of patients.
• Excellent Harris hip scores were observed in 89.7% of patients with successful horizontal offset restoration.
• Short-neck femoral implants achieved 90% horizontal offset restoration.

Conclusions:

• Pre-operative assessment of horizontal offset variations is essential before THA.
• Offset restoration was effectively achieved using standard offset (82.7%) and short-neck (13.3%) femoral components.
• The study highlights the importance of accurate templating for optimizing THA outcomes and restoring hip biomechanics.