Department of Orthopaedic Surgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima, 734-8551, Japan.
Sports Medical Center, Hiroshima University Hospital, Hiroshima, Japan.
BMC Musculoskelet Disord. 2022 Jun 14;23(1):569. doi: 10.1186/s12891-022-05523-2.
Hypermobility of the first tarsometatarsal (TMT) joint is frequently identified in patients with hallux valgus (HV); however, its association with the development of osteoarthritis in the first TMT joint in such patients remains unknown. The purpose of this study was to clarify the distribution of subchondral bone density of the first TMT joint via computed tomography (CT) using Hounsfield units (HU).
Patients were divided into three groups: the osteotomy (20 feet; 20 women, mean age: 61.8 years), arthrodesis (23 feet; two men, 21 women, 71.2 years), and control group (patients without HV deformity who had undergone CT scans of the foot; 13 feet; seven men, six women, 29.7 years). The HU ratios were calculated, which were defined as the HU value of each subdivision of the subarticular spongiosa of the first TMT joint [dorsomedial (DM), dorsolateral (DL), plantomedial (PM), and plantolateral (PL)] divided by the HU values of the entire joint surface. The ratios for the osteotomy, arthrodesis, and control groups were compared. The degradation of the articular cartilage in the first TMT joint was histologically graded in the arthrodesis group. Tukey-Kramer multiple comparison analysis was conducted to compare the HU ratios among the three groups, and the histological grade in each subdivision.
The arthrodesis group demonstrated high HU ratios in the DM area of the medial cuneiform, and significantly lower HU ratios in the PL area of the first metatarsal. Lower HU ratios in the DL area were observed in both the osteotomy and the arthrodesis group when compared to that in the medial cuneiform of the control group. The histological evaluation indicated nearly normal articular cartilage for all subdivided areas in both the medial cuneiform and the first metatarsal in patients with severe HV.
Although high subchondral bone density was identified in the DM area of the medial cuneiform in severe HV, only mild degradation was histologically observed in the articular cartilage of the first TMT joint. Our findings suggest that the indications for arthrodesis of the first TMT should be reconsidered based on the severity of the degenerative changes in the first TMT joint.
第一跖楔关节（TMT）过度活动在拇外翻（HV）患者中经常被发现；然而，其与此类患者第一 TMT 关节骨关节炎发展的关系尚不清楚。本研究旨在通过 CT（Hounsfield 单位，HU）明确第一 TMT 关节软骨下骨密度的分布。
患者分为三组：截骨术（20 足；20 名女性，平均年龄：61.8 岁）、融合术（23 足；2 名男性，21 名女性，71.2 岁）和对照组（无 HV 畸形且足部 CT 扫描的患者；13 足；7 名男性，6 名女性，29.7 岁）。计算 HU 比值，定义为第一 TMT 关节软骨下 subarticular 海绵骨的每个亚区（DM，背内侧；DL，背外侧；PM，跖内侧；PL，跖外侧）的 HU 值除以整个关节面的 HU 值。比较截骨术、融合术和对照组的比值。融合术组对第一 TMT 关节的关节软骨退化进行组织学分级。采用 Tukey-Kramer 多重比较分析比较三组间 HU 比值和各亚区的组织学分级。
融合术组内侧楔骨 DM 区 HU 比值较高，第一跖骨 PL 区 HU 比值明显较低。与对照组相比，截骨术和融合术组的 DL 区 HU 比值较低。严重 HV 患者的内侧楔骨和第一跖骨所有亚区的组织学评估均显示关节软骨几乎正常。
尽管严重 HV 中内侧楔骨 DM 区发现软骨下骨密度高，但第一 TMT 关节的关节软骨仅在组织学上观察到轻度退变。我们的研究结果表明，应根据第一 TMT 关节退行性改变的严重程度重新考虑第一 TMT 融合术的适应证。
