Study design: Cohort study.
Objectives: To describe calf muscle endurance recovery and to explore factors predictive of poor calf muscle endurance recovery 1 year after surgical repair of an Achilles tendon rupture (ATR).
Background: ATR is a common sports-related injury and is often managed with open surgical repair. After ATR repair most patients return to usual activities 6 months after surgery. However, calf endurance impairment can persist up to 6 years, possibly impacting performance of daily activities and sport.
Methods: A secondary analysis of a 73-patient cohort from a randomized controlled trial assessing the effects of early weight bearing after surgical repair of an ATR was performed. Calf muscle endurance recovery was measured by single-heel raises using a customized counting device at 6 months and 1 year postoperatively. Descriptive statistics were used to outline recovery of calf muscle endurance. Physical and patient-reported outcomes were examined for their association with calf-muscle endurance recovery. Multiple linear regression analysis was performed to explore variables associated with recovery of calf endurance 1 year postoperatively.
Results: Mean recovery of calf muscle endurance was 76% at 1 year. Multivariate regression analysis showed an association of being female, reporting no resting pain at 3 months, and physical functioning and calf endurance at 6 months, with better recovery of calf endurance at 1 year.
Conclusions: Calf muscle endurance at 1 year remained impaired in a considerable portion of the sample. Pain, gender, and physical functioning are likely important factors in determining recovery of calf muscle endurance.
Level of evidence: Prognosis, level 2b.J Orthop Sports Phys Ther 2010;40(6):345-351, Epub 15 April 2010. doi:10.2519/jospt.2010.3204.