Cusano Joseph, Johnson Jacob M, Dworkin Myles, Morrissey Patrick, Casey Jack C, Piana Lauren E, Schilkowsky Rachel M, Molino Janine, Gil Joseph A
Brown University, East Providence, RI, USA.
Quinnipiac University, North Haven, CT, USA.
Hand (N Y). 2025 Jul 10:15589447251348507. doi: 10.1177/15589447251348507.
The purpose of this study is to evaluate the rotational stability of 1-screw versus 2-screw antegrade fixation in distal metaphyseal ulnar shortening osteotomies (DMUSOs) using matched cadaveric forearm specimens. In addition, we aim to assess the mode of failure for each construct, specifically determining whether failure occurs due to hardware failure or peri-implant fractures.
Sixteen fresh-frozen cadaveric forearm specimens, organized into 8 matched pairs, were used. Ulnas were harvested, transected at the midshaft, and all soft tissue attachments were removed. A 5-mm oblique shortening osteotomy was created in the distal metaphysis, proximal to the ulnar head. Fixation was performed using either a single Acutrak 2 Mini 3.5 mm screw or 2 Acutrak 2 Micro 2.5 mm screws. Under a constant 10 N axial compressive load, specimens were cyclically loaded at 5°/second, beginning at 0.25 N m, and increasing by 0.25 N m every 500 cycles. Testing continued until failure, defined as either 10° of rotational displacement or catastrophic structural failure.
The 2-screw construct exhibited significantly greater torque resistance compared with 1-screw fixation (0.84 N m [95% confidence interval, CI: 0.61-1.08] vs 0.63 N m [95% CI: 0.52-0.73], = .016). In all instances, failure occurred due to rotational displacement exceeding 10°.
In a matched cadaveric study examining DMUSO constructs, 2 smaller headless compression screws provided greater rotational stability than a single larger headless compression screw. The antegrade 2-screw fixation may allow for improved rotational stability across the DMUSO, allowing short-arm immobilization postoperatively, with earlier wrist pronosupination.
本研究的目的是使用匹配的尸体前臂标本，评估1枚螺钉与2枚螺钉顺行固定在尺骨远端干骺端缩短截骨术（DMUSO）中的旋转稳定性。此外，我们旨在评估每种固定结构的失效模式，具体确定失效是否由于内植物失效或植入物周围骨折所致。
使用16个新鲜冷冻的尸体前臂标本，分为8对匹配组。截取尺骨，在骨干中部横断，并去除所有软组织附着。在尺骨头近端的远端干骺端制作一个5毫米的斜行缩短截骨。使用1枚Acutrak 2 Mini 3.5毫米螺钉或2枚Acutrak 2 Micro 2.5毫米螺钉进行固定。在10 N恒定轴向压缩载荷下，标本以5°/秒的速度循环加载，从0.25 N·m开始，每500个循环增加0.25 N·m。测试持续到失效，定义为旋转位移10°或灾难性结构失效。
与1枚螺钉固定相比，2枚螺钉的固定结构表现出显著更高的抗扭矩能力（0.84 N·m [95%置信区间，CI：0.61 - 1.08] 对0.63 N·m [95% CI：0.52 - 0.73]，P = 0.016）。在所有情况下，失效均由于旋转位移超过10°所致。
在一项研究DMUSO固定结构的匹配尸体研究中，2枚较小的无头加压螺钉比1枚较大的无头加压螺钉提供了更大的旋转稳定性。顺行双螺钉固定可能会改善DMUSO的旋转稳定性，允许术后短臂固定，并更早进行腕关节旋前旋后活动。
