Takedown of Ankle Fusions and Conversion to Total Ankle Replacements

Background: With ankle replacements gaining credibility, there is a small subset of patients who might benefit from a conversion of an ankle fusion to a replacement. The objective of this study is to present clinical and radiographic results of patients who had their ankle fusion converted to total ankle arthroplasty (TAA).

Methods: Patients presented to the senior author with ongoing ankle pain following fusion or increasing pain after a period of relative comfort after an ankle fusion. Outcomes were evaluated preoperatively and postoperatively with the Veterans Rand Health Survey (VR-12), Ankle Osteoarthritis Scale (AOS), and visual analog scale (VAS) pain scale. A patient satisfaction survey was also distributed.

Results: All ankle fusion conversions between April 2010 and December 2019 were included. Fifty-one patients (30 females) with the mean age of 62.6 (range, 37-83) years were followed. Mean follow-up was 4.2±2.3 (range, 2-11.5) years. Two patients were lost to follow-up (1 is deceased). Pre- and postoperative mean patient-reported outcome scores were all significantly different between groups except VR-12 mental subscale scores. VR-12 physical scores improved from 28.7±8.9 preoperatively to 38.9±9.9 (P < .001) postoperatively; VR-12 mental score was stable. AOS pain and disability subscales similarly improved: 55.9±24.4 to 27.9±25.4 (P < .001) and 61.7±21.1 to 31.1±25.7 (P < .001), respectively. VAS pain improved from a mean of 64.5±27.3 to 29.4±27.7 (P < .001). There was no tibiotalar dorsiflexion or plantarflexion with the ankle fusion. Initial postoperative visit revealed that average dorsiflexion was 10.9±5.93 degrees and average plantarflexion was 14.1±5.22 degrees. At the latest follow-up, dorsiflexion improved significantly to 15.5±6.33 degrees (P < .001), with no significant improvement in plantarflexion (P = .980).

Conclusion: In this single-surgeon longitudinal study of 51 patients with a painful, malaligned, or nonhealed ankle fusion treated with an ankle replacement, we found highly satisfactory functional outcomes at an average of 4.2 years. Continued long-term follow-up will reveal whether the longevity of these replacements is comparable to primary replacements.