Effect of Achilles Tendon Lengthening and Gastrocnemius Recession on Radiographic Tibiotalar Motion Following Total Ankle Replacement

Background: Surgeons frequently add an Achilles tendon lengthening or gastrocnemius recession to increase dorsiflexion following total ankle replacement. Previous studies have looked at the effects of these procedures on total tibiopedal motion. However, tibiopedal motion includes motion of the midfoot and hindfoot as well as the ankle replacement. The current study examined the effects of Achilles tendon lengthening and gastrocnemius recession on radiographic tibiotalar motion at the level of the prosthesis only. Methods: Fifty-four patients with an average of 25 months follow-up after total ankle replacement were divided into 3 groups: (1) patients who underwent Achilles tendon lengthening, (2) patients who had a gastrocnemius recession, (3) patients with no lengthening procedure. Tibiotalar range of motion was measured on lateral dorsiflexion-plantarflexion radiographs using reference lines on the surface of the implants. Results: Both Achilles tendon lengthening and gastrocnemius recession significantly increased tibiotalar dorsiflexion when compared to the group without lengthening. However, the total tibiotalar range of motion among the 3 groups was the same. Interestingly, the Achilles tendon lengthening group lost 11.7 degrees of plantarflexion compared to the group without lengthening, which was significant. Conclusion: Both Achilles tendon lengthening and gastrocnemius recession increased radiographic tibiotalar dorsiflexion following arthroplasty. Achilles tendon lengthening had the unexpected effect of significantly decreasing plantarflexion. Gastrocnemius recession may be a better choice when faced with a tight ankle replacement because it increases dorsiflexion without a compensatory loss of plantarflexion. Level of Evidence: Level III, retrospective comparative study.