Ligaments Are More Horizontal in Progressive Collapsing Foot Deformity (PCFD)

PCFD involves progressive ligamentous and bone changes. While osseous deformities are well described, ligament orientation is the focus of this investigation.

Study design

This retrospective study reviewed MRI and radiographs 39 patients – 23 PCFD and 16 controls. MRI was used to measure the coronal orientations of three ligaments: the cervical, the interosseous talocalcaneal, and superomedial spring ligaments. Radiographs assessed talonavicular coverage, Meary angle, talar declination, Kite angle, and calcaneal pitch.

Key insights

Patients with PCFD showed significantly more horizontal ligament orientations compared to controls:

• Cervical ligament: 25.5° in PCFD vs. 45° in controls (P < .001)

• Superomedial spring ligament: 11.5° vs. 23.1° (P <. 001)

• Interosseous talocalcaneal: 39.5° vs. 49° (P = .005)

Radiographs showed classic deformity patterns, including:

• Reduced talonavicular coverage: 64.5% in PCFD vs. 80.9% in controls

• Increased Meary angle: 22.2° vs. −2.3°

• Elevated talar declination: 37° vs. 20.6°

• Decreased calcaneal pitch: 15.5° vs. 24.6°

What it means

Nonweightbearing MRI reveals that patients with PCFD have more horizontally oriented subtalar ligaments, suggesting altered ligament alignment contributes to deformity.