Jaffri Abbis, Park Joseph, Hart Joe, Hertel Jay, Saliba Susan
Department of Physical Therapy, Creighton University, Omaha, Nebraska, United States.
Department of Orthopedic Surgery, University of Virginia, Charlottesville, Virginia, United States,.
PLoS One. 2025 Aug 21;20(8):e0325028. doi: 10.1371/journal.pone.0325028. eCollection 2025.
The intrinsic foot muscles (IFM), or foot core, provides stability to the foot skeleton. IFM dysfunction has been linked to foot and ankle injuries; however, the functional assessment of IFM in lower extremity conditions remains a clinical conundrum. We undertook a large study to understand the differences in muscle size and quality of IFM across a spectrum of conditions including Chronic Ankle Instability (CAI), Patellofemoral Pain (PFP), 1st Metatarsophalangeal Joint (1st MTPJ) arthrodesis and in patients with diabetes. This study compares IFM morphology and tissue quality in patients across these conditions and healthy control group individuals.
This study included 119 participants: 35 PFP, 29 CAI, 8 with 1st MTPJ arthrodesis, 9 with Diabetes, and 38 healthy controls. Ultrasound imaging (USI) assessed cross-sectional area (CSA) for muscle size and echogenicity for muscle quality in the Abductor Hallucis (AbH) and Flexor Digitorum Brevis (FDB). All size measures were normalized to body mass. Analysis of Coavariance (ANCOVA) was performed between groups, controlling for age and sex, to identify differences.
Significant differences (P < 0.05) in the CSA of the AbH were found between all pathology groups and healthy control group, except for the 1st MTPJ group. CSA of FDB showed significant differences (P < 0.01) in all groups except the PFP and 1st MTPJ groups. For echogenicity, significant differences (P < 0.05) were found between groups for both AbH and FDB, while CAI, 1st MTPJ, and PFP groups showed higher FDB echogenicity. Large effect sizes were found for CSA and echogenicity in all groups except PFP.
This is the first study to our knowledge to collectively analyze multiple clinical groups with suspected IFM weakness in functional position for both muscle size and quality. Significant changes in muscle size and quality were observed, suggesting that clinicians should assess and target IFM rehabilitation to improve foot and ankle function in these populations.
足部固有肌（IFM），即足部核心，为足部骨骼提供稳定性。IFM功能障碍与足踝部损伤有关；然而，在下肢疾病中对IFM进行功能评估仍然是一个临床难题。我们开展了一项大型研究，以了解在包括慢性踝关节不稳（CAI）、髌股疼痛（PFP）、第一跖趾关节（第一MTPJ）融合术以及糖尿病患者在内的一系列疾病中IFM的肌肉大小和质量差异。本研究比较了这些疾病患者与健康对照组个体的IFM形态和组织质量。
本研究纳入了119名参与者：35名PFP患者、29名CAI患者、8名第一MTPJ融合术患者、9名糖尿病患者以及38名健康对照者。超声成像（USI）评估了拇展肌（AbH）和趾短屈肌（FDB）的肌肉大小横截面积（CSA）以及肌肉质量回声。所有大小测量值均按体重进行标准化。在控制年龄和性别的情况下，对各组之间进行协方差分析（ANCOVA）以确定差异。
除第一MTPJ组外，所有病理组与健康对照组之间的AbH横截面积均存在显著差异（P < 0.05）。除PFP组和第一MTPJ组外，FDB的横截面积在所有组中均显示出显著差异（P < 0.01）。对于回声，AbH和FDB两组之间均存在显著差异（P < 0.05），而CAI组、第一MTPJ组和PFP组的FDB回声更高。除PFP组外，所有组的CSA和回声均发现有较大的效应量。
据我们所知，这是第一项对多个疑似IFM功能位肌力减弱的临床组进行肌肉大小和质量综合分析的研究。观察到肌肉大小和质量有显著变化，这表明临床医生应评估并针对IFM进行康复治疗，以改善这些人群的足踝功能。
