School of Biomedical Engineering, Faculty of Engineering, The University of Western Ontario, Ontario, Canada.
Department of Hand Surgery and Microsurgery Unit, Sheba Medical Center, Affiliated to Sackler School of Medicine, Tel Aviv University, Tel Hashomer, Ramat Gan, Israel.
J Hand Surg Am. 2021 Nov;46(11):1024.e1-1024.e8. doi: 10.1016/j.jhsa.2021.02.020. Epub 2021 Apr 17.
Although the consequences of scaphoid nonunion have been well-established, the implications of malunions are not well-known. To date, malunions have mainly been studied with 2-dimensional imaging. The objective of this study was to employ 3-dimensional computed tomography (CT) imaging and inter-bone distance mapping to determine the implications of a scaphoid malunion on 3-dimensional joint surface area (JSA) (a measure of joint contact area) at an average of 7 ± 2 years (range, 4-12 years) after fracture.
In 14 subjects with previous unilateral, malunited scaphoid fractures, we measured the 3-dimensional JSA using reconstructed CT bone models of the carpus. The JSA was compared within each individual, comparing images of the wrist collected at the time of fracture (baseline) and 7 years later (follow-up CT scans).
There was a significant increase in the measured JSA (reduced joint space) at the scaphotrapezial (23% increase) and scaphocapitate (13% increase) joints when the baseline and follow-up scans of the wrist were compared. An increased JSA indicates that the 2 opposing surfaces are closer in contact and have a reduced joint spacing reflective of degenerative changes. However, participants in this study showed no radiographic signs of degenerative changes in the wrists at midterm follow-up.
An increase in JSA was found in patients with a malunited scaphoid in the scaphotrapezial and scaphocapitate joints of the wrist an average of 7 years after injury, but these joint changes were not evident in measured radiographic signs of arthritis.
As early as 4 years after injury, the 3-dimensional JSA is significantly increased at the scaphocapitate and scaphotrapezial joints. Future work is needed to determine the implication of this increased in 3-dimensional JSA on the underlying subchondral bone, and to observe these patients for longer to determine whether degenerative changes develop.
尽管舟状骨骨不连的后果已得到充分证实，但舟状骨畸形愈合的影响尚不清楚。迄今为止，主要通过二维成像研究畸形愈合。本研究的目的是采用三维 CT 成像和骨间距离测绘来确定骨折后平均 7±2 年（4-12 年）时，舟状骨畸形愈合对三维关节面面积（JSA）（关节接触面积的测量指标）的影响。
在 14 例单侧、畸形愈合的舟状骨骨折患者中，我们使用腕关节的 CT 骨模型重建来测量三维 JSA。在个体内比较了基线时（骨折时）和 7 年后（随访 CT 扫描）采集的腕关节图像。
与基线腕关节扫描相比，当比较随访 CT 扫描时，舟月和舟头关节的 JSA （关节间隙减小）明显增加（舟月关节增加 23%，舟头关节增加 13%）。JSA 增加表明两个相对表面的接触更紧密，关节间隙减小反映了退行性变化。然而，在中期随访时，这些研究参与者的腕关节没有显示出退行性变化的放射学迹象。
在骨折后平均 7 年，畸形愈合的舟状骨患者的舟月和舟头关节的 JSA 增加，但这些关节变化在关节炎的放射学测量指标中并不明显。
早在受伤后 4 年，舟头和舟月关节的三维 JSA 就明显增加。需要进一步的研究来确定这种三维 JSA 增加对下软骨下骨的影响，并观察这些患者更长时间，以确定是否会发生退行性变化。
