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Malpositioning of radial head prostheses: an in vitro study
Edward Yian1, Wolfram Steens, Erich Lingenfelter
1Balgrist, Department of Orthopaedic Surgery, University of Zurich, Zurich, Switzerland.
Journal of Shoulder and Elbow Surgery
|April 22, 2008
Summary
Anatomic radial head replacement is challenging, often leading to malalignment. Bipolar implants showed better stability than rigid ones under unstable elbow conditions, suggesting clinical relevance.
Area of Science:
- Orthopedic Surgery
- Biomechanical Engineering
- Prosthetics Research
Background:
- Nonanatomic insertion of radial head prostheses can cause maltracking and capitellar erosion.
- Accurate prosthetic placement is crucial for restoring elbow joint function and stability.
Purpose of the Study:
- To evaluate the feasibility of achieving anatomic radial head replacement.
- To assess radiocapitellar prosthetic subluxation under simulated elbow instability.
Main Methods:
- In vitro biomechanical analysis of 10 intact and reconstructed elbows.
- Comparison of rigid uncemented, rigid cemented, and bipolar radial head prostheses.
- Assessment of prosthesis-shaft alignment and radiocapitellar subluxation under posterolateral rotatory stress.
Main Results:
- Consistent anatomic insertion of radial head prostheses was not achieved; malalignment up to 21 degrees was frequent.
- Rigid prostheses exhibited significant radiocapitellar subluxation (>30%) after coronoid resection and stress.
- Bipolar devices demonstrated self-aligning capabilities, resulting in subluxation comparable to intact elbows.
Conclusions:
- Achieving consistently anatomic radial head replacement remains a challenge.
- Bipolar radial head prostheses offer superior radiocapitellar stability compared to rigid implants in unstable conditions.
- Further clinical investigation is warranted to validate these biomechanical findings.
