Gray Alia B, Alolabi Bashar, Ferreira Louis M, Athwal George S, King Graham J W, Johnson James A
Hand and Upper Limb Center, University of Western Ontario, London, Ontario, Canada.
J Hand Surg Am. 2013 Sep;38(9):1753-61. doi: 10.1016/j.jhsa.2013.05.004. Epub 2013 Jul 3.
The coronoid process has been recognized as a critical component in maintaining elbow stability. In the case of comminuted coronoid fractures, where repair is not possible or has failed, a prosthesis may be beneficial in restoring the osseous integrity of the elbow joint. The hypothesis of this in vitro biomechanical study was that a coronoid prosthesis would restore stability to the coronoid-deficient elbow.
An anatomically shaped metallic coronoid prosthesis was designed and developed based on computed tomography-derived measurements and optimized to account for average cartilage thickness. Elbow kinematics and stability were determined for 8 cadaveric arms in active and passive elbow flexion in the varus, valgus, horizontal, and vertical positions using an elbow motion simulator. Varus-valgus angulation and internal-external rotation of the ulna relative to the humerus were quantified in the intact state, after collateral ligament sectioning and repair (control state), after a simulated 40% transverse coronoid fracture, and after implantation of the coronoid prosthesis.
Internal rotation of the ulna increased with a 40% coronoid fracture in the horizontal and varus positions. Increases in varus angulation after coronoid fracture were also observed in the horizontal and varus positions, during active and passive flexion, respectively. Following implantation of the coronoid prosthesis, elbow kinematics were restored similar to control levels in all elbow positions.
Our findings support our hypothesis that an anatomically shaped coronoid prosthesis would be effective in restoring stability to the coronoid-deficient elbow.
This study provides evidence that the use of an anatomical implant restores stability to the coronoid-deficient elbow and rationale for further study and development of this method. For comminuted coronoid fractures, where repair is not possible or has failed, our research indicates that a prosthesis may be a feasible treatment option.
冠突已被认为是维持肘关节稳定性的关键组成部分。在粉碎性冠突骨折无法修复或修复失败的情况下，假体可能有助于恢复肘关节的骨完整性。本体外生物力学研究的假设是，冠突假体可恢复冠突缺损肘关节的稳定性。
基于计算机断层扫描测量结果设计并开发了一种解剖形状的金属冠突假体，并进行了优化以考虑平均软骨厚度。使用肘关节运动模拟器，对8具尸体手臂在肘内翻、外翻、水平和垂直位置的主动和被动肘关节屈曲时的运动学和稳定性进行了测定。在完整状态、侧副韧带切断和修复后（对照状态）、模拟40%横向冠突骨折后以及植入冠突假体后，对尺骨相对于肱骨的内翻-外翻成角和内外旋转进行了量化。
在水平位和内翻位，40%冠突骨折时尺骨内旋增加。在水平位和内翻位，分别在主动和被动屈曲时，也观察到冠突骨折后内翻成角增加。植入冠突假体后，所有肘关节位置的肘关节运动学均恢复到与对照水平相似。
我们的研究结果支持我们的假设，即解剖形状的冠突假体可有效恢复冠突缺损肘关节的稳定性。
本研究提供了证据，表明使用解剖型植入物可恢复冠突缺损肘关节的稳定性，并为该方法的进一步研究和开发提供了理论依据。对于无法修复或修复失败的粉碎性冠突骨折，我们的研究表明假体可能是一种可行的治疗选择。
