Clinical and multi-segment kinematic analysis of a modified Grice arthrodesis to correct type II adult-acquired flat-foot

Background: Adult acquired flat foot (AAFF) is a symptomatic postural alteration of the foot due to modifications in bony structures and/or soft tissues supporting the medial longitudinal arch. For the most severe cases, when orthotic solutions do not provide enough pain relief, surgery may be necessary.

Research question: Is it possible to restore a normal medial longitudinal arch and to correct the static and dynamic frontal plane alignment of the rearfoot via a modified Grice surgical procedure in AAFF patients?

Methods: Eleven patients with stage II AAFF were recruited in the study and underwent the Grice procedure. Patients were assessed via gait analysis using a validated multi-segment foot protocol. Double-leg standing static posture and foot joint kinematics during barefoot walking were measured before surgery and at a mean follow-up of 15 ± 8 months. Twenty-seven age-matched healthy subjects without foot morphological alterations were used as control. Patients' feet were clinically assessed via the Foot Function Index and the Foot Posture Index. Wilcoxon signed rank test was used to assess differences in kinematic and spatio-temporal parameters between pre-op and follow-up evaluations. 1D statistical parametric mapping was used to assess differences in temporal profiles of foot joint rotations.

Results: The clinical indexes significantly improved at post-op (p < 0.05). No differences in sagittal plane static and dynamic joint rotations were observed between pre-op and post-op. In the frontal plane, metatarsus to calcaneus and midfoot to calcaneus rotation angles significantly improved from pre-op to post-op, with the latter resulting consistent with control data. Range of motion and maximum value of the medial longitudinal arch angle were reduced following surgery.

Significance: The modified Grice procedure restored a good frontal-plane alignment of rearfoot and midfoot, and the clinical scores provided evidence of its effectiveness in significantly reducing pain and improving the quality of daily activities.