• 作者：Cholawish Chanlalit MD^a ; ^b ; Dave R. Shukla MB ; BCh ; BAO^b ; James S. Fitzsimmons BSc^b ; Kai-Nan An PhD^b ; Shawn W. O&#x2019 ; Driscoll MD ; PhD^b ; ^{odriscoll.shawn@mayo.edu" rel="nofollow}
• 关键词：Radial head ; elbow joint ; instability ; prosthesis ; biomechanics
• 刊名：Journal of Shoulder and Elbow Surgery
• 出版年：2011
• 出版时间：September 2011
• 年：2011
• 卷：20
• 期：6
• 页码：885-890
• 全文大小：519 K
• ISSN：S1058274611001108

Background

Hypothesis

The shape (depth and radius of curvature) of the articulating dish of a radial head prosthesis affects radiocapitellar stability.

Materials and methods

Radiocapitellar stability due to concavity-compression was evaluated in 8 fresh frozen elbows before and after radial head replacement with 2 different designs of radial head implants (RH 1 and RH 2). Both functioned as monopolar implants. Peak forces resisting subluxation and force-displacement characteristics were compared between the 2 and to the native radial head.

Results

Radial head design significantly affected radiocapitellar stability. RH 1, which had a deeper dish than RH 2, required significantly higher peak forces to subluxate the radiocapitellar joint. The peak subluxation forces and the slopes of the force-displacement curves were not significantly different from the native radial head for RH 1, but they were for RH 2.

Conclusion

The shape of the articular dish (depth, radius of curvature) of a monopolar radial head implant affects its contribution to radiocapitellar stability. An implant that mimics normal anatomy is more effective than a shallow radial head implant with a radius of curvature that is longer than normal.