Chen Shuo, Huang Fuguo, Zhong Gang, Cen Shiqiang, Xiang Zhou, Li Jian
Department of Orthopaedics, West China Hospital, Sichuan University, Chengdu Sichuan, 610041, P.R. China.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2010 Feb;24(2):215-8.
To investigate whether or not posterolateral rotatory instability of the elbow is due to type-I and type-II coronoid process fracture together with anterior bundle of medial collateral ligament (AMCL) injury so as to provide a theoretic basis for its clinical treatment.
Ten fresh-frozen upper extremities were collected from cadavera which was donated voluntarily with no evidence of fracture, dislocation, osteoarthritis, mechanical injury of the surrounding ligament and joint capsule. They included 9 males and 1 female with an average age of 25.1 years (range, 19-40 years), including 3 cases at left sides and 7 cases at right sides. All specimens were transected at the upper midhumeral and carpal levels preserving the distal radioulnar joints to get the bone-ligament specimens. An axial load of 100 N compressing the elbow joint was applied along the shaft of the forearm in the sagittal plane through the biomechanical study system. The load-displacement plot was measured and analyzed at elbow flexion of 90, 60, and 45 degrees and under four conditions (intact elbow, type-I coronoid process fracture, type-I coronoid process fracture with AMCL deficient, and type-II coronoid process fractures with AMCL deficient).
The posterior displacements were maximum at 90 degrees elbow flexion. Hence, the results at 90 degrees elbow flexion were analyzed: under condition of intact elbows, the posterior displacement was the smallest (2.17 +/- 0.42) mm and the posterolateral rotatory stability was the greatest; under condition of type-I coronoid process fracture, the posterior displacement was (2.20 +/- 0.41) mm, showing no significant difference compared with that of the intact elbow (P > 0.05); under condition of type-I coronoid process fracture with AMCL deficient, the posterior displacement was (2.31 +/- 0.34) mm, showing no significant difference compared with that of intact elbow (P > 0.05); and under condition of type-II coronoid process fracture with AMCL deficient, the posterior displacement was (2.65 +/- 0.38) mm, showing a significant difference compared with that of intact elbow (P < 0.05). There was no macroscopic ulnohumeral dislocation or radial head dislocation during the experiment.
An simple type-I coronoid process fracture or with AMCL deficient would not cause posterolateral rotatory instability of elbow and may not need to be repaired. But type-II coronoid process fractures with AMCL deficient can cause posterolateral rotatory instability of elbow, so the coronoid process and the AMCL should be repaired or reconstructed to restore posterolateral rotatory stability as well as valgus stability.
探讨肘关节后外侧旋转不稳定是否由Ⅰ型和Ⅱ型冠状突骨折合并内侧副韧带前束（AMCL）损伤所致，为其临床治疗提供理论依据。
从自愿捐献的尸体上获取10个新鲜冷冻的上肢，无骨折、脱位、骨关节炎、周围韧带和关节囊机械损伤的证据。其中男性9例，女性1例，平均年龄25.1岁（19 - 40岁），左侧3例，右侧7例。所有标本均在肱骨中上部和腕部水平横断，保留远端桡尺关节，获取骨 - 韧带标本。通过生物力学研究系统，在矢状面沿前臂长轴施加100 N的轴向载荷压缩肘关节。在肘关节屈曲90°、60°和45°以及四种情况下（完整肘关节、Ⅰ型冠状突骨折、Ⅰ型冠状突骨折合并AMCL损伤、Ⅱ型冠状突骨折合并AMCL损伤）测量并分析载荷 - 位移曲线。
肘关节屈曲90°时后移位最大。因此，分析了肘关节屈曲90°时的结果：在完整肘关节情况下，后移位最小（2.17±0.42）mm，后外侧旋转稳定性最大；在Ⅰ型冠状突骨折情况下，后移位为（2.20±0.41）mm，与完整肘关节相比无显著差异（P＞0.05）；在Ⅰ型冠状突骨折合并AMCL损伤情况下，后移位为（2.31±0.34）mm，与完整肘关节相比无显著差异（P＞0.05）；在Ⅱ型冠状突骨折合并AMCL损伤情况下，后移位为（2.65±0.38）mm，与完整肘关节相比有显著差异（P＜0.05）。实验过程中未出现明显的尺肱关节脱位或桡骨头脱位。
单纯的Ⅰ型冠状突骨折或合并AMCL损伤不会导致肘关节后外侧旋转不稳定，可能无需修复。但Ⅱ型冠状突骨折合并AMCL损伤可导致肘关节后外侧旋转不稳定，因此应修复或重建冠状突和AMCL，以恢复后外侧旋转稳定性和外翻稳定性。
