Rahman Ayesha M, Montero-Lopez Nicole, Hinds Richard M, Gottschalk Michael, Melamed Eitan, Capo John T
1 New York University Hospital for Joint Diseases, New York City, USA.
Hand (N Y). 2018 Mar;13(2):202-208. doi: 10.1177/1558944717691129. Epub 2017 Feb 2.
Forearm immobilization techniques are commonly used to manage distal radius, scaphoid, and metacarpal fractures. The purpose of our study was to compare the degree of rotational immobilization provided by a sugar-tong splint (STS), short arm cast (SAC), Munster cast (MC), and long arm cast (LAC) at the level of the distal radioulnar joint (DRUJ), carpus, and metacarpals.
Seven cadaveric upper extremity specimens were mounted to a custom jig with the ulnohumeral joint fixated in 90° of flexion. Supination and pronation were unrestricted. K-wires were placed in the distal radius, scaphoid, and metacarpals using fluoroscopic guidance to measure the total arc of rotation referenced to the ulnar ex-fix pin. Baseline measurements followed by sequential immobilization with well-molded STS, SAC, MC, and LAC were obtained with 1.25, 2.5, and 3.75 ft-lb of supination and pronation force directed through the metacarpal K-wire. Each condition was tested 3 times. Digital photographs were taken perpendicular to the ulnar axis to analyze the total arc of motion.
The most effective constructs from least to greatest allowed rotational arcs were LAC, MC, SAC, and STS. Above-elbow constructs (MC, LAC) demonstrated superior immobilization compared with below-elbow constructs (SAC) ( P < .001). Circumferential constructs (SAC, MC, LAC) were superior to the noncircumferential construct (STS) ( P < .001). There were no significant differences between the MC and LAC in all conditions tested.
Both circumferential and proximally extended immobilization independently improved rotational control of the wrist. However, extending immobilization proximal to the epicondyles did not confer additional stability.
前臂固定技术常用于治疗桡骨远端、舟骨和掌骨骨折。我们研究的目的是比较糖钳式夹板（STS）、短臂石膏（SAC）、明斯特石膏（MC）和长臂石膏（LAC）在尺桡远侧关节（DRUJ）、腕骨和掌骨水平提供的旋转固定程度。
将7个尸体上肢标本安装到一个定制夹具上，尺肱关节固定在90°屈曲位。旋前和旋后不受限制。在透视引导下，将克氏针插入桡骨远端、舟骨和掌骨，以测量相对于尺骨外固定针的总旋转弧。在通过掌骨克氏针施加1.25、2.5和3.75英尺磅的旋前和旋后力的情况下，先进行基线测量，然后依次用塑形良好的STS、SAC、MC和LAC进行固定。每种情况测试3次。拍摄垂直于尺骨轴线的数码照片以分析总运动弧。
从允许旋转弧最小到最大，最有效的固定方式依次为LAC、MC、SAC和STS。与肘下固定方式（SAC）相比，肘上固定方式（MC、LAC）表现出更好的固定效果（P <.001）。环形固定方式（SAC、MC、LAC）优于非环形固定方式（STS）（P <.001）。在所有测试条件下，MC和LAC之间没有显著差异。
环形固定和近端延长固定均可独立改善腕关节的旋转控制。然而，将固定延长至髁上并不能提供额外的稳定性。
