DeAngelis Joseph P, Chen Alvin, Wexler Michael, Hertz Benjamin, Grimaldi Bournissaint Leandro, Nazarian Ara, Ramappa Arun J
Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Stoneman 10, Boston, MA, USA.
Department of Orthopaedic Surgery, Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
Knee Surg Sports Traumatol Arthrosc. 2015 May;23(5):1434-1441. doi: 10.1007/s00167-013-2775-6. Epub 2013 Nov 20.
Proximal biceps tenodesis is one method for treating biceps-related pain. Tenodesis protects the length-tension relationship of the biceps muscle, maintains strength, and provides a better cosmetic appearance than tenotomy. The purpose of this investigation was to compare the mechanical properties of a unicortical metal button and an interference screw in proximal biceps tenodesis.
Six pairs of fresh-frozen shoulders were dissected, leaving the proximal biceps tendon as a free graft. On each pair of shoulders, a biceps tenodesis was performed using an interference screw or a unicortical metal button. The specimens were mounted and a cyclic load (10-60 N) was applied at 1 Hz for 200 cycles, followed by an axial load to failure. The displacement, ultimate load to failure, and mode of failure were recorded.
Displacement in response to cyclic loading was 3.7 ± 2.2 mm for the interference screw and 1.9 ± 1.0 mm for the cortical button (P = 0.03). Load at failure for the interference screw was 191 ± 64 N (stiffness: 24 ± 11 N/mm) and 183 ± 61 N (stiffness: 24 ± 7. N/mm) for the unicortical button (P = n.s. for both cases).
As a novel technique for subpectoral biceps tenodesis, a unicortical button demonstrated significantly less displacement in response to cyclic loading than the interference screw. The ultimate load to failure and stiffness for the two methods were not different. In this way, a unicortical button may provide a reliable alternative method of fixation with a potentially lower risk of post-operative humeral fracture and a construct that permits early mobilization following biceps tenodesis.
肱二头肌近端腱固定术是治疗肱二头肌相关疼痛的一种方法。腱固定术可保护肱二头肌的长度-张力关系，维持力量，且比腱切断术具有更好的外观效果。本研究的目的是比较单皮质金属纽扣和干涉螺钉在肱二头肌近端腱固定术中的力学性能。
解剖6对新鲜冷冻肩关节，保留肱二头肌近端肌腱作为游离移植物。在每对肩关节上，使用干涉螺钉或单皮质金属纽扣进行肱二头肌腱固定术。将标本安装好，以1Hz的频率施加10-60N的循环载荷，持续200个循环，然后施加轴向载荷直至破坏。记录位移、破坏时的极限载荷和破坏模式。
干涉螺钉在循环载荷下的位移为3.7±2.2mm，皮质纽扣为1.9±1.0mm（P=0.03）。干涉螺钉破坏时的载荷为191±64N（刚度：24±11N/mm），单皮质纽扣为183±61N（刚度：24±7N/mm）（两种情况P均无统计学意义）。
作为一种新型的胸小肌下肱二头肌腱固定术技术，单皮质纽扣在循环载荷下的位移明显小于干涉螺钉。两种方法的破坏时极限载荷和刚度无差异。这样，单皮质纽扣可能提供一种可靠的替代固定方法，术后肱骨骨折风险可能更低，且该结构允许肱二头肌腱固定术后早期活动。
