Importance of the posterior bundle of the medial ulnar collateral ligament

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• 作者：Dave R. Shukla ; MD^a ; ^{dshukla@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Elan Golan ; MD^b ; Philip Nasser ; MSME^a ; Maya Culbertson ; MFS^b ; Michael Hausman ; MD^a
• 关键词：Basic Science Study ; Biomechanics
• 刊名：Journal of Shoulder and Elbow Surgery
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：25
• 期：11
• 页码：1868-1873
• 全文大小：660 K

文摘

There has been a renewed interest in the pathomechanics of elbow dislocation, with recent literature having suggested that the medial ulnar collateral ligament is more often disrupted in dislocations than the lateral ligamentous complex. The purpose of this serial sectioning study was to determine the influence of the posterior bundle of the medial ulnar collateral ligament (pMUCL) as a stabilizer against elbow dislocation.

Methods

An elbow dislocation was simulated in 5 cadaveric elbows by mechanically applying an external rotation moment and valgus force. Medial ulnohumeral joint gapping was measured at 30°, 60°, and 90° of flexion in an intact elbow after sectioning of the medial collateral ligament's anterior bundle (aMUCL) and then after sectioning of the pMUCL as well.

Results

After sectioning of the aMUCL, the pMUCL was able to stabilize the joint against dislocation. After aMUCL sectioning, the proximal joint space significantly increased by 4.2 ± 0.6 mm at 30° of flexion and 2.6 ± 0.3 mm at 60° of flexion, although it did not dislocate. The gapping increase of 0.9 ± 0.6 at 90° of flexion did not reach significance. After sectioning of the pMUCL (after having already sectioned the aMUCL), all of the specimens frankly dislocated at all flexion angles.

Conclusions

An intact pMUCL can prevent elbow dislocation and limited joint subluxation to within 6.6 mm. Our findings indicate that repair or reconstruction may be warranted in certain circumstances (ie, residual instability after operative management of a terrible triad injury or after aMUCL reconstruction).