Department of Orthopaedics and Sports Medicine, University at Buffalo, Buffalo NY; SUNY Upstate Medical University Norton College of Medicine, Syracuse NY.
University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY.
J Hand Surg Am. 2024 Aug;49(8):752-756. doi: 10.1016/j.jhsa.2023.06.013. Epub 2023 Aug 4.
Wrist and thumb pathology can coexist leading to potential indications for proximal row carpectomy (PRC) and trapeziectomy. In this setting, the axial stability of the first ray is not known. We sought to evaluate axial subsidence of the first metacarpal in cadavers following trapeziectomy and trapeziectomy with PRC to determine the mechanical effects of the procedures performed concurrently.
Eleven fresh-frozen cadaveric distal forearm specimens were used in this study. The specimens were fixed in cement and mounted to a material test system frame. A predetermined force (20 N) was applied to the thumb metacarpal to simulate forces observed with lateral pinch. Axial displacement of the thumb metacarpal was measured. The application of force was repeated following trapeziectomy on each hand and then again following PRC. Analysis was performed to compare thumb metacarpal subsidence of the 3 groups: native, trapeziectomy, and trapeziectomy with PRC.
Before trapeziectomy, native cadaver specimens had an average of 5.1 ± 1.9 mm of thumb metacarpal subsidence under the material test system load (20 N), compared to 16.2 ± 3.4 mm following trapeziectomy, and 25.0 ± 5.5 mm for trapeziectomy with PRC.
We observed a significant increase in thumb metacarpal subsidence following concurrent trapeziectomy with PRC when compared to trapeziectomy alone. Our results suggest that performing both operations together would lead to a substantial risk of first ray subsidence.
When treating concurrent basilar thumb and wrist arthritis, it may be more effective to stage the procedures or use a form of thumb metacarpal suspension or arthrodesis.
腕部和拇指的病变可能同时存在，这导致可能需要行桡腕掌侧关节切开术（PRC）和大多角骨切除术。在此情况下，第一掌骨的轴向稳定性尚不清楚。我们旨在评估在施行大多角骨切除术后和 PRC 联合大多角骨切除术后第一掌骨的轴向沉降，以确定同期施行的这些手术的力学影响。
本研究使用了 11 个新鲜冷冻的尸体远侧前臂标本。标本固定于水泥中并安装于材料测试系统框架上。拇指掌骨施加预定的力（20N）以模拟侧捏时观察到的力。测量拇指掌骨的轴向位移。每只手施行大多角骨切除术后重复施加力，然后再次施行 PRC 联合大多角骨切除术后重复施加力。对 3 组进行分析以比较拇指掌骨的沉降：正常、施行大多角骨切除术后、PRC 联合大多角骨切除术后。
在施行大多角骨切除术前，正常尸体标本在材料测试系统负荷（20N）下的拇指掌骨平均沉降量为 5.1±1.9mm，而行大多角骨切除术后为 16.2±3.4mm，行 PRC 联合大多角骨切除术后为 25.0±5.5mm。
与单独施行大多角骨切除术相比，同期施行 PRC 联合大多角骨切除术时拇指掌骨的沉降明显增加。我们的结果表明，同时施行这两种手术会导致第一掌骨显著沉降的风险。
在治疗并发的基底拇指和腕关节炎时，分期施行这些手术或采用一种拇指掌骨悬吊或融合术可能更为有效。
