Walsh Stephen, Reindl Rudy, Harvey Edward, Berry Gregory, Beckman Lorne, Steffen Thomas
McGill University Health Centre, Department of Orthopaedic Surgery, Montreal General Hospital, Room B5.159.5, 1650 Cedar Ave, Montreal, Quebec, Canada H3G 1A4.
Clin Biomech (Bristol). 2006 Dec;21(10):1027-31. doi: 10.1016/j.clinbiomech.2006.06.005. Epub 2006 Aug 17.
Newer internal fixation devices with a locking mechanism between the plate and the screw have recently been released. The efficacy of these plates in the proximal humerus has yet to be fully described. There is a need to compare the biomechanical properties of efficacy of plate fixation with or without locking screws for surgery of two-part proximal humerus fractures. Multiple-plane locking plate and cloverleaf plate designs were tested to determine their ability to maintain fixation on the humeral head.
Eight matched pairs of cadaveric shoulders with 7-millimeter osteotomy defects at the surgical neck simulating two-part fractures of the proximal humerus were loaded to failure in thirty degrees of glenohumeral abduction. One side was repaired with a proximal humerus locking plate and the other with a cloverleaf plate. The rotator cuff musculature was then loaded via a servo-hydraulic testing machine under displacement control to simulate the deforming forces present in vivo.
The average maximum load to failure was greater in proximal humerus locking plates than in cloverleaf plates (876 versus 712; P=0.04).
In the cadaveric, two-part proximal humerus fracture model that was created, the locking plate displayed significantly greater holding power of the humeral head. Clinical relevance is unproven but may be manifested in vivo as improved early range of motion exercises and functional outcome.
最近推出了新型内固定装置，其钢板与螺钉之间具有锁定机制。这些钢板在肱骨近端的疗效尚未得到充分描述。有必要比较锁定螺钉和非锁定螺钉钢板固定治疗肱骨近端二部分骨折手术的生物力学特性。测试了多平面锁定钢板和三叶钢板设计，以确定它们在肱骨头维持固定的能力。
八对匹配的尸体肩部，在手术颈部有7毫米截骨缺损，模拟肱骨近端二部分骨折，在肩关节外展30度时加载至失效。一侧用肱骨近端锁定钢板修复，另一侧用三叶钢板修复。然后通过伺服液压试验机在位移控制下加载肩袖肌肉组织，以模拟体内存在的变形力。
肱骨近端锁定钢板的平均最大失效载荷大于三叶钢板（876比712；P=0.04）。
在建立的尸体肱骨近端二部分骨折模型中，锁定钢板对肱骨头的握持力明显更大。临床相关性未经证实，但在体内可能表现为早期活动范围练习和功能结果的改善。
