SLR - March 2021 - Sara K. Stachura

Functional Outcomes of Total Ankle Arthroplasty at a Mean Follow-up of 7.6 Years

Reference: Brodsky JW, Scott DJ, Ford S, Coleman S, Daoud Y. Functional Outcomes of Total Ankle Arthroplasty at a Mean Follow-up of 7.6 Years. J Bone Joint Surg Am. 2021; 00:1-6. doi: 10.2106/JBJS.20.00659.

Level of Evidence: Therapeutic Level IV

Scientific Literature Review

Reviewed By: Sara K. Stachura, DPM 
Residency Program: Swedish Medical Center – Seattle, WA

Podiatric Relevance: There are two main surgical options for patients with end stage ankle arthritis: ankle fusion and total ankle arthroplasty (TAA). Ankle fusion is associated with complications including: inherent loss of ankle motion, adjacent joint arthritis, nonunion, and gait limitations. TAA was developed to avoid these complications. There is currently a limited number of studies that review functional outcomes of TAA. Long term follow-up with reported functional outcomes improves our understanding of the natural history of a TAA in order to improve patient education and decision making. This is the longest-term follow-up study of gait after TAA to date.   

Methods: This was a retrospective review on a prospectively collected database. Patients all underwent unilateral primary TAA, preoperative 3-dimensional gait analysis within two weeks, and post-operative gait analysis at a minimum of five years after surgery. Function was assessed via walking speed, ankle push-off power, and joint range of motion via a three-dimentional gait analysis at a self-selected speed over a 10 meter distance. Reflective markers were placed according to the Modified Helen Hayes marker configuration. A minimum of 20 gait cycles were utilized to average temporospatial and kinematic parameters with five force-plate readings per side. Multiple linear regression analysis was performed to evaluate patient demographics. A paired t test with sample standard deviations was used to compare pre and postoperative gait analysis.

Results: A total of 33 patients were examined. 28 underwent TAA with STAR implants and 5 had the Salto Talaris Ankle. Postoperative gait analysis was performed at a mean of 7.6 years (range 5-13.3 years). There were significant improvements in cadence, step length, walking speed, total sagittal plane range of motion, plantarflexion at initial contact, and maximum plantarflexion. The number of years since TAA had no effect on postoperative gait analysis. Females and older patients had a shorter step length both pre and postoperatively. 

Conclusions: This study supports the hypothesis that patients would show significant improvements in temporospatial and kinematic function at a minimum of five years after TAA compared to preoperatively. This is similar to the results of other studies with shorter follow up periods. A previous study conducted in the same laboratory with a mean follow up of 4.4 years showed higher parameters in cadence, velocity, total sagittal range of motion and peak ankle power, though all continued to be substantially improved compared to preoperatively. The authors attribute this mild decline in parameters to aging of the patients. Despite this, follow-up duration was not correlated with degradation in gait function. This study shows that improvements in gait persist over a medium-term follow up after TAA. 

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