Factors associated with calf muscle endurance recovery 1 year after achilles tendon rupture repair.

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.