Qualitative study of musculoskeletal tissues and their radiographic correlates in diabetic neuropathic foot deformity

Diabetes mellitus (DM) with peripheral neuropathy (PN) results in foot deformity increasing ulceration, joint dislocation, and amputation risk. This study describes the frequency and severity of foot and ankle musculoskeletal abnormalities and their relationship to radiographic alignment in people with DMPN with (DMPN + MCD) and without (DMPN - MCD) medial column deformity (MCD) compared to age- and body mass index-matched controls without DMPN or MDC.

DMPN + MCD (n = 11), DMPN - MCD (n = 12), and controls (n = 12) were studied. A radiologist scored foot and ankle magnetic resonance images (MRI) for abnormalities in tendons/fascia, ligaments, muscles, joints, and bones. Higher scores represent greater abnormalities. Foot alignment was measured from lateral weightbearing radiographs. Frequency of abnormalities between groups and relationships between abnormalities and foot alignment in the combined group (n = 35) were examined.

DMPN + MCD had higher total muscle, joint, and bone scores compared to controls and higher total joint scores than DMPN - MCD. DMPN - MCD had higher total muscle scores than controls. DMPN + MCD higher bone and joint scores were driven by increased frequency of osteophytes, cartilage damage, focal bone marrow edema, new bone formation, and subchondral cysts. Significant correlations included cuboid height and total bone and joint scores (ρ = -0.37 and ρ = -0.40, respectively) and talar declination angle and total joint score (ρ = 0.38).

High contrast resolution MRI allowed identification of structural lesions of the foot affecting the cartilage surfaces, bone marrow, and soft tissue supports in patients with DMPN + MCD. As expected, the presence of bone and joint lesions on MRI were strongly associated with DMPN + MCD; surprisingly, although the sample is small, lesions of the soft tissue supports were not associated with MCD. While MRI is not done routinely to investigate MCD, opportunistic use of the information from MRI done for the common clinical indications may allow early identification of the structural lesions associated with MCD and facilitate early, aggressive therapy.

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