Relationship of Postoperative Achilles Tendon Elongation With Plantarflexion Strength Following Surgical Repair.

Background: Little data exist regarding the adverse effects of Achilles tendon (AT) elongation after rupture repair on plantarflexion strength. This study aimed to investigate the effect of AT elongation measured using AT resting angle (ATRA) on the plantarflexion strength in patients with surgically treated acute AT rupture. Methods: A retrospective chart review was performed on 40 patients (15 female and 25 female) who underwent open operative repair due to an acute AT rupture. At the final follow-up, AT elongation was assessed using ATRA. Plantarflexion strength (peak torques and angle-specific torques) was measured using an isokinetic dynamometer. All variables were obtained from the operated and unoperated contralateral ankles of the patients. Results: The mean ATRA was greater in the operated ankles (mean, 57 degrees; range, 39-71 degrees) compared with the unoperated ones (mean, 52 degrees; range, 36-66 degrees; P = .009). Except the plantarflexion torque at 20 degrees of plantarflexion (P = .246), all the other angle-specific torques were lower in the operated ankles (P < .05). Peak flexion torque at 30 degrees/s was lower in the operated ankle (P = .002). A negative correlation was found between operated/unoperated (O/N) ATRA and O/N plantarflexion torque ratios at 0 degrees (r = -0.404; P = .01), 10 degrees (r = -0.399; P= .011), and 20 degrees (r = -0.387; P = .014). Conclusion: Postoperative AT elongation measured using ATRA may have a deleterious effect on the plantarflexion strength in patients with surgically treated acute AT rupture