Tang Peter, Swart Eric, Konopka Geoffrey, Raskolnikov Dima, Katcherian Christopher
Department of Orthopaedic Surgery, Allegheny Health Network, Pittsburgh, PA 15212, USA.
J Hand Surg Am. 2013 Jul;38(7):1340-5. doi: 10.1016/j.jhsa.2013.03.054. Epub 2013 Jun 6.
Proximal row carpectomy (PRC) is used as a treatment for a variety of wrist pathologies to maintain motion and to improve strength and decrease pain. Several studies have looked at how PRC alters wrist characteristics, although they did not provide an explanation for the variability observed in outcomes. Studies have classified the capitate into 3 unique types: round, V-shaped, or flat. We hypothesized that these differences in morphology could affect the contact biomechanics between the radius and the capitate after PRC.
A total of 14 cadaveric wrists underwent PRC. They were classified by capitate morphology and then loaded to 200 N in a neutral position, flexion, and extension. We measured contact area, contact pressure, and location using pressure-sensitive film in all 3 positions and compared their morphology types.
Nine wrists had a round-type capitate, 4 had a V-shaped capitate, and 1 had a flat capitate, which we excluded from statistical analysis. Comparing round and V-shaped types, we found no differences in contact area, pressure, or location in any wrist position For the V-shaped capitates, there was increased contact pressure in flexion and extension compared with the wrist in neutral. Center of pressure translated dorsal and radial in flexion to volar and ulnar in extension for all types.
When we compared V-shaped and round-type capitates, we found no significant differences in contact characteristics of the wrist after PRC. There were some differences in contact pressure for V-shaped capitates in various wrist positions.
Differences between round and V-shaped capitates do not appear to affect contact biomechanics after PRC. Thus, these 2 capitate shapes may not necessarily be a factor in the decision-making process to perform PRC.
近端排腕骨切除术（PRC）用于治疗多种腕部疾病，以维持活动度、增强力量并减轻疼痛。多项研究探讨了PRC如何改变腕部特征，尽管它们并未对观察到的结果差异作出解释。研究已将头状骨分为3种独特类型：圆形、V形或扁平形。我们推测这些形态差异可能会影响PRC术后桡骨与头状骨之间的接触生物力学。
对14具尸体手腕进行PRC手术。根据头状骨形态进行分类，然后在中立位、屈曲位和伸展位加载至200 N。我们在所有3个位置使用压敏膜测量接触面积、接触压力和位置，并比较它们的形态类型。
9只手腕的头状骨为圆形，4只为V形，1只为扁平形，后者被排除在统计分析之外。比较圆形和V形头状骨，我们发现在任何腕部位置，接触面积、压力或位置均无差异。对于V形头状骨，与中立位手腕相比，屈曲位和伸展位的接触压力增加。所有类型的压力中心在屈曲时向背侧和桡侧移动，在伸展时向掌侧和尺侧移动。
当我们比较V形和圆形头状骨时，发现PRC术后腕部的接触特征无显著差异。V形头状骨在不同腕部位置的接触压力存在一些差异。
圆形和V形头状骨之间的差异似乎不会影响PRC术后的接触生物力学。因此，这两种头状骨形状不一定是决定是否进行PRC的因素。
