Flexor hallucis longus tendon transfer for chronic Achilles tendon rupture. A retrospective study

Background The transfer of Flexor Hallucis Longus Tendon (FHL) is an established method for the treatment of chronic Achilles tendon ruptures. An extensive examination of power, strength, endurance and complications related to this procedure is presented. Methods 21 patients treated with open FHL transfer for chronic Achilles tendon rupture were studied retrospectively. Medical records were reviewed. The patients were examined with a test battery for triceps surae strength, functional tests and PROMs. Results The median maximal concentric strength was equal,1300 vs 1336 W, comparing affected with unaffected side. The endurance tests showed a larger difference, 219 J vs. 2398 J, respectively. The median AOFAS score was 87. 11 of 21 patients sustained one or more complications; the most common were infection, disturbed wound healing, and clawing of small toes. Conclusions Patients achieve almost normal maximal strength after open FHL transfer, but endurance is notably lower. The complication rate was high. Keywords Chronic Achilles ruptureFHL tendon transferFunctional outcomeComplication