Repair Versus Non‐Repair of Lateral Ulnar Collateral Ligament in Elbow Varus Posteromedial Rotatory Instability Treatment: A Comparative Study

ObjectiveTo compare the effects of repairing and not repairing the lateral ulnar collateral ligament (LUCL) when surgically treating elbow varus posteromedial rotatory instability (PMRI).MethodsIn this retrospective study spanning June 2014 to February 2019, 24 patients with elbow PMRI who were treated surgically were assigned to group RL (Repair LUCL) or group NL (Non‐repair LUCL) depending on whether the LUCL was repaired. Hospitalization time, operation time, intraoperative blood loss, and related complications were reviewed. The elbow range of motion (ROM), the visual analog scale (VAS), the Mayo elbow performance score (MEPS), and the disabilities of the arm, shoulder, and hand (DASH) score were used for functional assessment.ResultsAmong the 24 patients with PMRI, 15 were assigned to group RL and nine were assigned to group NL. The mean blood loss (184.66 ± 20.3 vs 207.33 ± 19.447, P < 0.001), the operation time (98.88 ± 12.693 min vs 184.66 ± 20.3 min, P < 0.001) were significantly lower in group RL compared to group NL. There were no significant differences between the two groups in time until surgery and follow‐up time (6.66 ± 1.838 vs 6.11 ± 1.900 days, 25.53 ± 2.099 vs 26.11 ± 2.891 months, P = 0.577, P = 0.486). All of the patients achieved bone union. The elbow flexion‐extension ROM (122.00° ± 3.162°vs 121.11° ± 3.333° at 12 months, P = 0.520) and pronation‐supination ROM (154.53° ± 3.335° vs 155.55° ± 4.639° at 12 months, P = 0.537). Both groups achieved similar results in MEPS score (90.53 ± 2.695 vs 89.77 ± 3.865, P = 0.578) and DASH (9.77 ± 1.897 vs 9.99 ± 1.550, P = 0.772) score at the final follow‐up. And the MEPS score revealed excellent results (87% in group RL, 89% in group NL).The VAS scores decreased significantly in group RL (from 6.13 ± 0.990 to 1.93 ± 0.593) and group NL (from 5.77 ± 1.481 to 1.88 ± 0.781), and no significant differences in preoperative or final follow‐up were observed between the two groups (P = 0.487, P = 0.876). Complications observed in group NL with one patient occurred cubital tunnel syndrome 3 months after the operation, the patient underwent ulnar nerve simple neurolysis and the symptoms were relieved after 3 weeks.ConclusionFor patients with elbow PMRI, satisfactory functional outcomes can be yielded with non‐repair of the LUCL as long as the stable elbow joint is performed during operation.     

Lateral collateral ligament deficiency of the elbow joint: A modeling approach

A computational model capable of predicting the effects of lateral collateral ligament deficiency of the elbow joint would be a valuable tool for surgical planning and prediction of the long‐term consequences of ligament deficiency. The purpose of this study was to simulate lateral collateral ligament deficiency during passive flexion using a computational multibody elbow joint model and investigate the effects of ligament insufficiency on the kinematics, ligament loads, and articular contact characteristics (area, pressure). The elbow was placed initially at approximately 20° of flexion and a 345 mm vertical downward motion profile was applied over 40 s to the humerus head. The vertical displacement induced flexion from the initial position to a maximum flexion angle of 135°. The study included simulations for intact, radial collateral ligament deficient, lateral ulnar collateral ligament deficient, and combined radial and lateral ulnar collateral ligament deficient elbow. For each condition, relative bone kinematics, contact pressure, contact area, and intact ligament forces were predicted. Intact and isolated radial collateral ligament deficient elbow simulations were almost identical for all observed outcomes. Minor differences in kinematics, contact area and pressure were observed for the isolated lateral ulnar collateral ligament deficient elbow compared to the intact elbow, but no elbow dislocation was detected. However, sectioning both ligaments together induced substantial differences in kinematics, contact area, and contact pressure, and caused complete dislocation of the elbow joint. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1645–1655, 2016.     

Unstable Simple Elbow Dislocation Treated with the Repair of Lateral Collateral Ligament Complex

Background

Unstable simple elbow dislocation (USED) repair is challenged by the maintenance of joint reduction; hence, primary repair or reconstruction of disrupted ligaments is required to maintain the congruency and allow early motion of the elbow. We evaluated the effectiveness and the outcome of lateral collateral ligament (LCL) complex repair with additional medial collateral ligament (MCL) repair in cases of USED.

Methods

We retrospectively reviewed 21 cases of diagnosed USED without fractures around the elbow that were treated with primary ligament repair. In all cases, anatomical repair of LCL complex with or without common extensor origin was performed using suture anchor and the bone tunnel method. Next, the instability and congruency of elbow for a full range of motion were evaluated under the image intensifier. MCL was repaired only if unstable or incongruent elbow was observed. Clinical outcomes were evaluated using the Mayo elbow performance score (MEPS) and radiographic outcomes on last follow-up images.

Results

All cases achieved a stable elbow on radiographic and clinical results. LCL complex repair alone was sufficient to obtain the stable elbow in 17 of 21 cases. Four cases required additional MCL repair after restoration of the LCL complex. The overall mean MEPS was 91 (range, 70 to 100): excellent in 12 cases, good in 7 cases, and fair in 2 cases. All 17 cases with LCL complex repair only and 2 of 4 cases with additional MCL repair had excellent or good results by MEPS.

Conclusions

USED requires surgical treatment to achieve a congruent and stable joint. If the repair of lateral stabilizer such as LCL complex acquires enough joint stability to maintain a full range of motion, it may not be necessary to repair the medial stabilizer in all cases of USED.     

Assessment of Rotational Instability with Disruption of the Accessory Collateral Ligament of the Thumb MCP Joint: A Biomechanical Study

OBJECTIVES: The objective of this paper was to biomechanically investigate rotational stability of the thumb after ulnar collateral ligament (UCL) and accessory collateral ligament (ACL) disruption and repair at the metacarpal joint of the thumb. METHODS: Twelve fresh frozen adult cadaveric thumbs were used. The torsion test was performed under constant rotation of 1/s through 30 arc of metacarpal phalangeal (MCP) joint. The torsional resistance was determined for four categories: first no intervention of the UCL structures (control), next with the proper UCL cut at the distal insertion, then with the additional ACL ligament cut, and lastly with the repair of only the proper UCL. The decrease on the amount of torsional rigidity for each of the last three categories was determined and compared. Each thumb was used as its own control. Significance of the differences in each test categories was statistically determined. RESULTS: After the proper UCL was cut, the torsional rigidity of the MCP joint was reduced 35.18 +/- 17.56% (p < 0.001). When, additionally, the ACL was cut, the torsional rigidity of the MCP joint was further reduced to 49.34 +/- 16.82% (P < 0.001). After repair of only the proper UCL, the torsional rigidity of the MCP joint improved, but still showed a considerable reduction from controls. The amount of reduction was not consistent among specimens and was 13.52 +/- 16.40%. CONCLUSIONS: The ACL ligament is a contributor of rotary stability as well as a provider of lateral stability. Leaving the ruptured ACL unrepaired causes some residual rotating instability and that may lead to future rotational instability of the MCP joint.     

肘关节尺侧副韧带屈曲角度与负荷关系的生物力学研究

[目的]研究肘关节尺侧副韧带(UCL)在不同的肘关节屈曲角度时生物力学特性的变化.[方法]选取8对新鲜冰冻肘关节尸体标本,测量每个标本在前臂旋前、旋后、中立位时,肘关节不同被动屈曲角度下UCL的张力变化;测量UCL在肘关节不同屈曲角度下(30°、50°、70°、90°)外翻应力试验时失效载荷与屈曲角度的关系.[结果]肘关节在被动屈曲0°～57°时,对UCL前束的前带和后带均没有产生超过3%的张力,屈曲导致的张力改变对后带的影响有显著性(P＜0.01),对前带的影响无显著性(P=0.128).在57°以后,后带上的张力随着屈曲角度的增大而增加,在100°～130°左右的范围达到最大.前臂的旋转对韧带张力的影响无显著性.在肘关节屈曲90°时UCL断裂失效所需载荷最大,在屈曲30°时最小.UCL断裂好发部位为其前束肱骨内侧髁止点处.[结论]UCL损伤或者重建术后的固定角度应为肘关节屈曲＜57°,早期的康复锻炼肘关节屈曲0°～57°为安全范围.肘关节在屈曲90°时具有最高的外翻稳定性,可以减少UCL损伤机率.