SLR - September 2023 - Brower
Title: Ankle plantar flexor muscle performance and patient reported outcomes in people following total ankle arthroplastyReference: DiLiberto FE, Vora AM, Wilson WC, Miller SA, Meardon SA, Haddad SL. Ankle plantar flexor muscle performance and patient reported outcomes in people following total ankle arthroplasty. Clin Biomech (Bristol, Avon). 2022 Feb;92:105576. doi: 10.1016/j.clinbiomech.2022.105576. Epub 2022 Jan 12. PMID: 35063817.
Level of Evidence: Level III
Scientific Literature Review
Reviewed By: David Brower, DPM
Residency Program: Our Lady of Lourdes Memorial Hospital in Binghamton, NY.
Podiatric Relevance: Total ankle arthroplasty is an increasingly popular treatment option for end-stage arthritis. One of the goals of the procedure is to help the patient return to normal activity with reduced pain while maintaining some degree of joint motion and function. While physical therapy is commonly used following surgery, the authors of the study evaluate how well the ankle plantarflexors function following total ankle arthroplasty compared to a control group. If strength at the ankle is maintained or improved, it is assumed that gait and function would also improve following surgery. The author’s hypothesized that ankle power would not be different before and after surgery but would also be lower than the control and that post-operative plantarflexion strength would be positively correlated with gait speed and ankle power.
Methods: A prospective, case-control study was performed with patients scheduled to receive total ankle arthroplasty for end-stage ankle arthritis. 19 patients were included with 19 matched controls. Patients were excluded if they had an uncorrectable foot deformity, had prior fusion procedures, or were found unsuitable for total ankle arthroplasty. Data was collected from arthroplasty patients pre-operatively as well as at 6 months and 2 years post-operatively. All patients were sent to physical therapy post-operatively for individualized treatment. Arthroplasty patients completed the FAAM-ADL pre-operatively and post-operatively, as well as the PROMIS-PF Short Form 10a at 2 years post-op. Gait speed via 6 min walk test was assessed. Plantar flexion strength was measured using a dynamometer. Ankle power during gait was assessed with a motion capture system and a force plate, with the average of 3 walking trials being used.
Results: FAAM-ADL scores were improved 6 months post-operatively but were lower than the control group at follow-up. PROMIS-PF T-score was 56.2 at 2 years post-op. Gait speed improved at 6 month follow-up, however it was still 0.14m/s slower than control group. Ankle power during gait was not changed post-operatively and was lower than control group. Positive correlations were found between ankle plantar flexion strength, ankle power during gait, and gait speed post-operatively, between post-op ankle plantarflexion torque and PROMIS-PF scores, and between post-operative ankle power and FAAM-ADL scores.
Conclusions: The authors concluded that ankle power before and after total ankle arthroplasty was not different, but it was lower than the control group. They also found that ankle plantarflexion strength and power were related to gait speed and patient outcomes. These results show the importance of an individualized approach to rehabilitation following total ankle arthroplasty. If the patient is aware that their ankle strength post-operatively will not be different than it is pre-operatively, it will likely help them set realistic expectations. These findings also present the opportunity to study the effect of targeted muscle strength training before and/or after surgery for patients undergoing total ankle arthroplasty see if this would improve patient outcomes to the point that they match those of a control group.