Is Total Ankle Arthroplasty Justified in Stiff Ankles?

Abstract

Category: Ankle Arthritis. Introduction/Purpose: Although recent studies have shown comparability of gait function following total ankle arthroplasty (TAA) and ankle arthrodesis, TAA is regarded to be functionally advantageous by preserving tibiotalar motion. However, it is unknown whether arthritic ankles with severe loss of sagittal plane motion are appropriate surgical candidates for arthroplasty. This study was undertaken to address the question: Is there a rationale for motion-preserving surgery in patients with little or no preoperative sagittal plane motion? Methods: A retrospective review of 76 patients who underwent isolated TAA with a minimum one-year follow-up, including patient demographics and pre and postoperative gait studies was conducted. Using a linear regression model, an effect size for total preoperative sagittal ROM was calculated, as well as effects of age, and patient demographics. Gait function was evaluated for postoperative improvement using multivariate analysis to determine the influence the variable on parameters of gait. P-values of < 0.05 were considered statistically significant. Results: Outcomes/p-values are listed in table 1. Temporal Spatial Older patients had slower preoperative/postoperative walking speeds, and increased age resulted in diminished function. Increased preoperative ROM predicted greater preoperative and trended towards greater postoperative step length. Greater preoperative ROM predicted less total improvement. Kinematic Age was predictive of improved postoperative plantarflexion with negligible clinical significance. Preoperative ROM predicted greater postoperative ROM although less improvement was noted. Preoperative/postoperative sagittal angle at toe off was greater with increased preoperative ROM. No improvement was detected. Preoperative and postoperative plantarflexion/dorsiflexion were both greater with increased preoperative ROM. Less overall improvement in plantarflexion was noted with greater preoperative ROM. Kinetic Preoperative ROM was predictive of greater preoperative/postoperative ankle power. Greater preoperative ROM resulted in less improvement in power. Conclusion: Irrespective of preoperative total sagittal range of motion, there was a statistically and clinically significant improvement in function as measured by multiple, objective parameters of gait. While pre-operative range of motion was predictive of overall post-operative gait function, patients with greater pre-operative range of motion experienced less overall improvement in gait. The data show that TAA can offer statistically significant, and clinically meaningful improvement in gait function and is a reasonable treatment alternative even in patients with end-stage tibiotalar arthritis who have very limited preoperative sagittal range of motion.