Improvement of Outcomes During the First Two Years Following Total Ankle Arthroplasty

Many studies of total ankle arthroplasty (TAA) have focused on the range of motion and functional outcomes at the time of intermediate-term follow-up. The purpose of our study was to analyze the progression of ankle hindfoot range of motion and patient-reported measures through the first 2 years following TAA.

The charts of 134 patients who had been treated with a TAA by a single surgeon were retrospectively reviewed, and 107 (109 TAAs) were included in the study. The overall range of motion in the sagittal plane was measured as the change in the position of the tibia relative to the floor on dedicated weight-bearing lateral radiographs made with the ankle in maximum plantar flexion and dorsiflexion preoperatively and at 3 months, 6 months, 1 year, and 2 years postoperatively. In addition, patients completed a visual analogue scale (VAS) for pain, the Foot and Ankle Ability Measure (FAAM) Activities of Daily Living (ADL) and Sports Subscales, and the Short Form-12 (SF-12) Physical (PCS) and Mental (MCS) Component Summary scores at each time interval.

The mean overall range of motion in the sagittal plane was 20.7° preoperatively and improved to 28.3°, 34.3°, 33.3°, and 33.3° at 3 months, 6 months, 1 year, and 2 years, respectively (p < 0.001). At each postoperative time point, the median VAS score was improved (p < 0.001) compared with the preoperative VAS score. Similarly, the FAAM and SF-12 scores were improved, compared with the preoperative score, at 6 months and later (p < 0.001). An increased range of motion correlated with a lower VAS score preoperatively (ρ = -0.31, p = 0.035) and at 1 year (ρ = -0.36, p = 0.003) postoperatively. An increased range of motion correlated with a higher FAAM ADL score at 3 months (ρ = 0.50, p = 0.012), 1 year (ρ = 0.26, p = 0.040), and 2 years (ρ = 0.39, p = 0.003) postoperatively.

Patients who underwent TAA had improvement, compared with preoperatively, in the overall sagittal plane range of motion up to 6 months and maintained improvement in pain and function scores up to 2 years. Pain scores remained improved throughout the 2-year follow-up period. A better range of motion was correlated with less pain as measured with the VAS. An increased range of motion postoperatively was correlated with better function as measured with the FAAM.

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.