Decreased ankle dorsiflexion is common after injury and may result in patient complaints of stiffness and subsequent injury. The weight-bearing lunge test (WBLT) is a simple clinical measure of dorsiflexion. Previous study has defined a 2.0cm side-to-side discrepancy in WBLT as likely significant. With review of current literature, ankle stiffness is a concept largely undefined; we aim to relate patient complaints of stiffness to WBLT.

This was a population-based inception cohort with longitudinal follow-up. Patients between ages 18–65 receiving surgical fixation for ankle fracture were screened. Pilon/plafond fractures, bilateral injuries, or polytrauma were excluded. At 6-weeks, 6-months, and 1-year WBLT was measured along with non-weight-bearing goniometry; and an Olerud-Molander ankle score completed.

155 patients were recruited (90 female, 65 male; mean age 42, range 20–67). 47% of injuries were unimalleolar, 17% bimalleolar, and 36% trimalleolar; 35% received syndesmotic fixation. 89% of patients reported feeling stiff at 6-weeks, 82% at 6-months, and 74% at 1-year. 98% of patients had ≥2.0cm discrepancy of WBLT at 6-weeks, 78% at 6-months, and 72% at 1-year. Different thresholds of WBLT (larger discrepancy or absolute negative measurement) had worse correlation with patient reported stiffness.

Our population had high incidence of stiffness at 1-year. The proportion of patients complaining of stiffness after ankle fracture was similar to that measured with ≥2.0cm discrepancy of WBLT. This is the first study that we are aware of that relates the WBLT and the previously reported threshold of 2.0cm to stiffness. This measurement may give clinicians a better objective idea regarding patient perception of a “stiff” ankle. Reducing side to side discrepancy in range of motion should be considered in rehabilitation rather than total range of motion.