Deficits in Heel-Rise Height and Achilles Tendon Elongation Occur in Patients Recovering From an Achilles Tendon Rupture

Abstract

Background: Whether an Achilles tendon rupture is treated surgically or not, complications such as muscle weakness, decrease in heel-rise height, and gait abnormalities persist after injury. Purpose: The purpose of this study was to evaluate if side-to-side differences in maximal heel-rise height can be explained by differences in Achilles tendon length. Study Design: Case series; Level of evidence, 4. Method: Eight patients (mean [SD] age of 46 [13] years) with acute Achilles tendon rupture and 10 healthy subjects (mean [SD] age of 28 [8] years) were included in the study. Heel-rise height, Achilles tendon length, and patient-reported outcome were measured 3, 6, and 12 months after injury. Achilles tendon length was evaluated using motion analysis and ultrasound imaging. Results: The Achilles tendon length test-retest reliability (intraclass correlation coefficient = 0.97) was excellent. For the healthy subjects, there were no side-to-side differences in tendon length and heel-rise height. Patients with Achilles tendon ruptures had significant differences between the injured and uninjured side for both tendon length (mean [SD] difference, 2.6-3.1 [1.2-1.4] cm, P = .017-.028) and heel-rise height (mean [SD] difference, –4.1 to –6.1 [1.7-1.8] cm, P = .012-.028). There were significant negative correlations ( r = −0.943, P = .002, and r = −0.738, P = .037) between the side-to-side difference in heel-rise height and Achilles tendon length at the 6- and 12-month evaluations, respectively. Conclusion: The side-to-side difference found in maximal heel-rise height can be explained by a difference in Achilles tendon length in patients recovering from an Achilles tendon rupture. Minimizing tendon elongation appears to be an important treatment goal when aiming for full return of function.