Dynamic evaluation of claw toe using three-dimensional motion analysis

Claw toe is a common spastic deformity of the lower limbs, but no objective analysis has been reported to date.

To establish a three-dimensional motion analysis method for toe movement in healthy individuals and in a patient with claw toe.

Twenty healthy individuals and one patient with claw toe were included in this cross-sectional study. Infrared reflective markers were attached to II toe of each participant. In the standing position and using a handrail, participants performed four elevations of the lower limb. The proximal interphalangeal (PIP) joint and metacarpophalangeal (MTP) joint angles were measured during the elevations using five cameras. The patient with hemiplegia underwent botulinum toxin therapy three times, with joint angles assessed before and at 1 month after each injection.

No marker detachment occurred due to contact or other external factors, and all assessments were completed successfully. In healthy individuals, PIP and MTP joint angles showed no change during repeated lower limb elevations. In contrast, the patient with claw toe showed increased flexion at the PIP and MTP joints, with progressive PIP joint flexion with increasing number of repetitions, but the MTP joint angle was unchanged.

Three-dimensional motion analysis enabled evaluation of toe motion and distinguished joint behavior between healthy individuals and a patient with claw toe, before and after botulinum toxin therapy.