gms | German Medical Science

Objectives: Tendon elongation is one of the most common complications of Achilles tendon rupture treatment. Changes in Achilles tendon length are directly correlated to Achilles tendon resting angle (ATRA). Tendon length is also expected to affect the plantar flexion strength. This study aims to investigate the relation between ankle plantar flexion strength and Achilles tendon length, measured by Achilles tendon resting angle.

Methods: 40 male patients (mean age 39.2 ±8.2, range 20 - 60) with surgically treated unilateral Achilles tendon rupture were enrolled in the study. There were 37 primary open repair and 3 V-Y plasty patients. Minimum follow-up was 1 year. Patients with any ankle or foot problem on the uninjured site were excluded. Patients were clinically examined for ATRA, passive dorsiflexion angle and calf bulk diameter and ankle isokinetic tests with Cybex 350 dynamometer were used for objective evaluation. 30°/sec -120°/sec peak torque and angle specific torque at 30°/sec -10, 0, 10, 20 degrees of plantar flexion were measured. Correlation test were used for investiation of any relation between clinical measurements and isokinetic test results.

Results and Conclusion: For the uninjured sides, mean ATRA was 52.0±5 degrees for the non-dominant legs and 53.75±7.3 degrees for dominant legs. Mean passive dorsiflexion increase was 0.28±3.9. Mean calf Muscle diameter loss was 0.71±1.2. There was strength loss at 0 (r=-0.404 p<0.05), 10 (r=-0.399 p<0.05) 20°(r=-0.387 p<0.05) plantar flexion degrees when ATRA increased. There was no correlation between ATRA degrees and 30°/sec -120°/sec peak torque values. The increase in ATRA (increase in tendon length) was significantly correlated to a loss of strength at 10 degrees (r=-0.343 p<0.05), and 20 degrees (r=-0.318 p<0.05) of plantar flexion. The decrease in calf bulk diameter was correlated to strength loss at 0 (r=0.312 p<0.05), 10 (r=0.340 p<0.05) and 20 degrees of plantar flexion (r=0.448 p<0.05). No correlation was found between ATRA or passive dorsiflexion degrees and 30°/sec -120°/sec peak torque values.

Elongation of Achilles tendon in surgically treated rupture cases was found to be correlated to a loss plantar flexion strength. Appropriate surgical techniques and rehabilitation protocols should be preferred to prevent any lengthening of the tendon.