[Long-term results with cement-free total hip prostheses (Zweymuller)]

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Medical Imaging

Background:

• Cementless total hip replacement is a common procedure for hip osteoarthritis.
• The Zweymüller stem is a widely used implant in hip arthroplasty.
• Long-term outcomes of specific implant designs require continuous evaluation.

Purpose of the Study:

• To evaluate the long-term subjective, clinical, and radiological outcomes of cementless total hip replacements using Zweymüller stems.
• To compare the performance of Zweymüller stems with different acetabular cup designs.
• To assess patient satisfaction and functional improvement after hip arthroplasty.

Main Methods:

• A retrospective study of 113 consecutively implanted Zweymüller stems with a mean follow-up of 8.9 years.
• Clinical and radiological assessments including Merle d'Aubigné and Harris Hip Scores.
• Analysis of radiolucent lines on X-rays and implant survival rates.

Main Results:

• High subjective satisfaction (96%) and low pain levels reported by patients.
• Significant improvement in functional scores: Harris Hip Score increased from 47.1 to 86.8.
• 10-year stem survival rate of 96% with a low complication rate; however, 81% showed proximal radiolucent lines.
• Significant differences in cup survival rates: 79% of polyethylene cups loosened vs. 8% of titanium cups.

Conclusions:

• Zweymüller stems demonstrate highly successful long-term results in cementless total hip replacement.
• Proximal radiolucent lines suggest potential concerns regarding distal stem anchoring.
• Zweymüller stems exhibit superior long-term survival compared to titanium acetabular cups.