Factors associated with calcar resorption in cemented total hip prostheses

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Radiology

Background:

• Calcar resorption is a known complication following total hip replacement (THR).
• Understanding the factors contributing to calcar resorption is crucial for improving long-term implant survival and patient outcomes.

Purpose of the Study:

• To identify patient-specific and mechanical factors associated with early calcar resorption after total hip replacement.
• To compare the incidence of calcar resorption between different prosthesis types and component orientations.

Main Methods:

• Retrospective analysis of patient data and radiograms from 237 total hip replacement procedures.
• Utilized a computer program to evaluate radiographic parameters and patient characteristics.
• Correlated various factors including patient demographics, preoperative aid use, prosthesis type (CAD-prosthesis vs. Charnley-Müller), femoral component alignment, acetabular cup orientation and size, and femur-pelvis distance with calcar resorption.

Main Results:

• Middle-aged patients and those with primary hip disease as the sole lower extremity dysfunction were more prone to calcar resorption.
• Patients not using walking aids preoperatively or postoperatively showed higher rates of resorption.
• The Computer Assisted Design (CAD)-prosthesis was associated with increased calcar resorption at 6 months compared to the Charnley-Müller prosthesis.
• Valgus-oriented femoral components showed a negative correlation with resorption.
• Vertical acetabular cup placement, larger cup sizes, and increased femur-pelvis distance were more common in patients with calcar resorption.

Conclusions:

• Mechanical factors appear to be the predominant drivers of early calcar resorption after total hip replacement.
• Findings suggest that implant positioning and design choices have significant clinical implications for long-term THR results.
• Further investigation into optimizing surgical techniques and implant selection is warranted to mitigate calcar resorption.