Calf Muscle Performance Deficits Remain 7 Years After an Achilles Tendon Rupture.

BACKGROUND

Optimizing calf muscle performance seems to play an important role in minimizing impairments and symptoms after an Achilles tendon rupture (ATR). The literature lacks long-term follow-up studies after ATR that describe calf muscle performance over time.

PURPOSE

The primary aim was to evaluate calf muscle performance and patient-reported outcomes at a mean of 7 years after ATR in patients included in a prospective, randomized controlled trial. A secondary aim was to evaluate whether improvement in calf muscle performance continued after the 2-year follow-up.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Sixty-six subjects (13 women, 53 men) with a mean age of 50 years (SD, 8.5 years) were evaluated at a mean of 7 years (SD, 1 year) years after their ATR. Thirty-four subjects had surgical treatment and 32 had nonsurgical treatment. Patient-reported outcomes were evaluated with Achilles tendon Total Rupture Score (ATRS) and Physical Activity Scale (PAS). Calf muscle performance was evaluated with single-leg standing heel-rise test, concentric strength power heel-rise test, and single-legged hop for distance. Limb Symmetry Index (LSI = injured side/healthy side × 100) was calculated for side-to-side differences.

RESULTS

Seven years after ATR, the injured side showed decreased values in all calf muscle performance tests ( P < .001-.012). Significant improvement in calf muscle performance did not continue after the 2-year follow-up. Heel-rise height increased significantly ( P = .002) between the 1-year (10.8 cm) and the 7-year (11.5 cm) follow-up assessments. The median ATRS was 96 (of a possible score of 100) and the median PAS was 4 (of a possible score of 6), indicating minor patient-reported symptoms and fairly high physical activity. No significant differences were found in calf muscle performance or patient-reported outcomes between the treatment groups except for the LSI for heel-rise repetitions.

CONCLUSION

Continued deficits in calf muscle endurance and strength remained 7 years after ATR. No continued improvement in calf muscle performance occurred after the 2-year follow-up except for heel-rise height.