Ankle Arthritis Networking: Getting the right treatment to the right patient first time

Comparison of Loss of Bone Height Following Total Ankle Arthroplasty Versus Tibiotalocalcaneal Arthrodesis

Ankle arthrodesis and total ankle arthroplasty are both well-accepted surgical treatment options for end-stage ankle arthrosis. However, total ankle arthroplasty has gained popularity as the survivability of implants is improving. It is understood that there is loss of bone height following tibiotalocalcaneal arthrodesis, but to our knowledge, this has not been investigated in the setting of total ankle arthroplasty. A retrospective radiographic review was conducted over a 5-year period. We investigated all patients who underwent a tibiotalocalcaneal arthrodesis or total ankle arthroplasty for treatment of ankle arthritis by a single fellowship-trained orthopedic surgeon. The anterior and posterior height measurements were measured on preoperative and postoperative lateral radiographs. Differences between preoperative and postoperative heights were analyzed through a series of analyses of covariance. One hundred and thirty-three patients and 143 operative extremities were included: 71 operative extremities in the tibiotalocalcaneal arthrodesis group (mean age 55.5 ± 13.3 years, BMI 32.2 ± 7.9) and 72 in the total ankle arthroplasty group (mean age 65.4 ± 9.5 years, BMI 30.7 ± 6.4). Statistical analysis demonstrated a loss of height in the tibiotalocalcaneal arthrodesis group, and an increased anterior and posterior height in the total ankle arthroplasty group. However, when comparing the arthroplasty group and arthrodesis group only the anterior height measurement reached statistical significance when stratified by gender (p < .001). The potential change in height is an important factor to consider during surgical planning as a limb length discrepancy may result.

Ankle joint pressure change before and after subtalar joint arthrodesis in varus and valgus malalignment of the tibia

Purpose: The compensation mechanism of subtalar joint in ankle with varus or valgus deformity is controversial and not well established. This biomechanical study aims to investigate how subtalar joint arthrodesis will affect the ankle joint pressure in varus and valgus malalignment of the tibia. Methods: Eight fresh-frozen human cadaver legs were tested in this study. A custom-made fixture was utilized and a total of 600N was applied to simulate weight-bearing. Intra-articular sensors (TeckScan) were inserted in the ankle joint to demonstrate the ankle joint pressure. Conditions include: Neutral, 5°, 10°, 15° and 20° varus, 5°, 10°, 15° and 20° valgus. Results: After the fusion of the subtalar joint, when the tibia is gradually inverted, the inside pressure of the ankle joint gradually increases, and the pressure on the outside of the ankle joint gradually decreases. When the tibia is gradually eversion, the pressure on the outside of the ankle joint gradually increases, and the inside of the ankle joint gradually decreases. Conclusions: After the subtalar joint is fused, the compensatory activity of the subtalar joint disappears, and the regulation of the pressure in the ankle joint will be lost. We hypothesized that the inversion compensation of the subtalar joint is more likely to occur than the eversion compensation.