The Effect of Endoscopic Partial Plantar Fasciotomy on Morphologic and Functional Properties of the Foot

Background: The lifetime risk of plantar fasciitis is 10%, and operative treatment in the form of endoscopic partial plantar fascia release are often performed in cases refractory for nonsurgical treatment. The effect of the operation on the biomechanical properties of the foot has only been sparsely studied. Methods: This is a prospective, observational study of 25 patients with plantar fasciitis, for a minimum of 3 months, verified by ultrasonographic scanning, who had endoscopic partial fasciotomy. A bony spur was resected if present. At the calcaneal insertion, the medial half of the central band of the plantar fascia was excised in full thickness. The biomechanical properties of the foot were evaluated before surgery and 12 months postoperatively. Results: Foot length increased 0.17 cm ( P = .03), the width of the central zone 0.35 cm ( P = .019), the modified arch index 0.05 ( P = .032), and the Foot Posture Index 1.0 ( P = .0014). There were no significant changes in rearfoot eversion angle, ankle dorsiflexion and jump distance, or in magnetic resonance imaging–measured 3D navicular position from pre- to postoperation, with or without loading, and no changes in ultrasonographically measured heel pad thickness. A tantalum bead (0.7-mm-diameter) was inserted during operation into the most proximal part of the released medial plantar fascia. Radiographs obtained few days postoperatively and 1 year later revealed no changes in the tantalum-calcaneus distance in supine position, but an increase from 48.3 to 50.7 mm ( P = .045) in one-leg standing, suggesting a higher flexibility of the remaining fascia. Patients with a body mass index above and below 27.0 demonstrated no significant differences in any of the assessments at 12 months. Conclusion: There were minimal changes in the measured foot morphologic and functional properties at 1-year follow-up, after endoscopic partial plantar fascia release. Level of Evidence: Level II, prospective cohort study.