Bone mineral density, gait analysis, and patient satisfaction, before and after ankle arthroplasty

Bone mineral density (BMD) and patient satisfaction were measured and gait analysis was performed in patients treated with unilateral dual-coated ankle arthroplasty. The study comprised 14 patients (eight women and six men) measured preoperatively and at a median of 15 (range, 12-26) months after surgery. BMD was measured bilaterally in the distal tibia and in the calcaneus. A plantar pressure analysis was performed, including foot contact duration and a new index for describing the ground reaction force curve called the Valley Index (VI). The patients also evaluated their level of pain, ability to cope with daily activities, adaptation of shoes, and walking ability before surgery and at follow-up on a visual analogue scale (VAS). Bone mass significantly increased adjacent to the tibial part of the prosthesis. The patients experienced less pain and improved walking and performance in daily activities. There was also a decrease in foot contact duration as well as an increase in VI and ankle range of motion. Change in bone mass was the variable that correlated best with the patients' evaluation of the general outcome of ankle arthroplasty. Correlations among other variables are described. The study concluded that a fairly simple analysis of the ground reaction force curve, bone mass measurements, and VAS can demonstrate that ankle arthroplasty is able to normalize gait, decrease foot contact duration, increase bone mass, and reduce pain.