Assessing the Efficacy of a Prefabricated Inflatable Ankle Orthotic Brace in Correcting Progressive Collapsing Foot Deformity With Weightbearing Computed Tomography: A Prospective Case Control Study.

Abstract

We aimed to evaluate the efficacy of a prefabricated inflatable ankle orthotic brace (IAOB) to improve the 3-dimensional (3D) foot alignment of patients with progressive collapsing foot deformity (PCFD) using weightbearing computed tomography (WBCT). We prospectively enrolled a consecutive series of symptomatic PCFD patients and a healthy control group matched for mean age, sex, and BMI. The primary endpoint was the paired change in FAO (%) with brace vs no brace. Each PCFD foot underwent 2 WBCT scans with and without an IAOB. The foot 3D alignment was assessed using the foot and ankle offset (FAO) under the assumption that IAOBs could improve at least 50% of the surgical FAO correction (-4.25%). Dedicated 3D measurements allowed the assessment of PCFD classes (from A to D). Both PCFD and control groups included 24 feet. Overall, 48 feet underwent 72 WBCT (24 unbraced PCFD, 24 braced PCFD and 24 controls). Median age was 55.5 years (IQR 26.3) in the PCFD group and 51.0 years (IQR 32.2) in the control group (<i>P</i> = .58), with a median BMI of 33.5 (IQR 13.4) and 25.4 (IQR 8.3), respectively (<i>P</i> = .24). Females comprised 58.3% of the control group and 54.2% of the PCFD group (<i>P</i> = .99). The FAO in the unbraced (6.6 ± 3.7) and braced (5.5 ± 4.2) PCFD group was not significantly improved (<i>P</i> = .1). After bracing, only class C PCFD showed significant improvement of the forefoot arch angle (<i>P</i> = .001) and talus-first metatarsal angle (<i>P</i> = .002). The other PCFD classes were not improved by the brace (class A <i>P</i> = .66, class B <i>P</i> = .44, class D <i>P</i> = .17). These findings suggest device-specific efficacy was limited to class C PCFD on static WBCT measures; clinical benefit remains unproven and warrants PROMs/MCID-anchored studies.