Distal radius fractures (DRFs) with dorsal malunion increase the risk of osteoarthritis (OA), although the cause of post-DRF OA is yet to be elucidated. To clarify the abnormal effects of a post-DRF dorsal radius deformity, we evaluated the bone density (BD) and stress-distribution patterns of the articular surface in dorsally malunited DRFs. In 36 cases of dorsally malunited DRFs following extra-articular fractures, we generated three-dimensional computerized models of the malunited distal radius from computed tomography data and extracted the subchondral bones of the radiocarpal joint (RCJ) and distal radioulnar joint (DRUJ). Both BD and stress distribution in the subchondral bones were quantitatively evaluated by comparing the affected and normal sides. Correlations of alterations in high-BD distribution and deformation angles were analyzed. The center of high-BD distribution from the center of the RCJ in the volar(-)-dorsal(+) direction was dorsal (0.56 ± 0.72 mm) on the affected side compared with the normal side (−0.15 ± 0.63 mm) [95% CI: 0.43, 1.00, P < 0.0001]. The maximum stress distribution was also dorsal on the affected side (2.34 ± 3.52 mm) compared with the normal side (−2.49 ± 1.62 mm) [95% CI: 0.89, 1.79, P < 0.0001]. The alterations in BD and stress distribution correlated with the dorsiflexion and radial deviation angles. In the DRUJ, there was no significant difference in BD between the affected and normal sides. In dorsally malunited DRFs, the alignment change of the RCJ resulted in high BD-concentration areas and stress distribution on the dorsal side of the radius, which may constitute a precursor for OA.

中文翻译：

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桡骨远端骨折背侧畸形愈合与腕部骨关节炎的关联：骨密度和应力分布模式与变形角相关的变化


桡骨远端骨折 (DRF) 伴背侧畸形愈合会增加骨关节炎 (OA) 的风险，尽管 DRF 后 OA 的原因尚未阐明。为了阐明 DRF 后背侧桡骨畸形的异常影响，我们评估了背侧畸形 DRF 的骨密度 (BD) 和关节面的应力分布模式。在 36 例关节外骨折后背侧畸形愈合的 DRF 病例中，我们根据计算机断层扫描数据生成了畸形远端桡骨畸形的三维计算机模型，并提取了桡腕关节 (RCJ) 和远端桡尺关节 (DRUJ) 的软骨下骨。通过比较受影响侧和正常侧，定量评估软骨下骨的 BD 和应力分布。分析了高BD分布变化与变形角度的相关性。与正常侧（-0.15±0.63mm）相比，从RCJ中心沿掌侧（-）-背侧（+）方向的高BD分布中心在患侧为背侧（0.56±0.72mm）[ 95% CI: 0.43, 1.00, P< 0.0001]。与正常侧 (−2.49 ± 1.62 mm) 相比，最大应力分布也在受影响侧的背侧 (2.34 ± 3.52 mm) [95% CI: 0.89, 1.79, P < 0.0001]。 BD 和应力分布的变化与背屈和径向偏差角相关。在 DRUJ 中，受影响侧和正常侧的 BD 没有显着差异。在背侧畸形的 DRF 中，RCJ 的排列变化导致桡骨背侧出现高 BD 浓度区域和应力分布，这可能构成 OA 的先兆。