Ankle Arthritis: Replacement and Valgus Deformity
As noted in my prior blog, arthritis will develop if there has been trauma to the ankle, such as with recurrent ankle sprains or with certain types of fractures, and in those who have systematic or inflammatory arthritis. In those who have ligament damage as the primary reason for the development of arthritis, it is very common to develop significant varus (the ankle is bowed inward and you walk on the outside of your foot/ankle) or valgus deformity (the ankle is bowed outward and you walk on the inside of your foot/ankle).
As much as I am always much more worried about patients with a varus alignment and the significant functional problems that they face, such as ankle instability, peroneal tendon tears, metatarsal stress fractures and sesamoiditis, when it comes to ankle replacement, a valgus ankle is a much more challenging problem than a varus ankle. Valgus hindfoot alignment can be at the level of the leg, the ankle, the subtalar joint, or a combination. There is so much to consider in the hindfoot….and then there are the forefoot compensatory changes. When the deformity is severe, most significant thing that drives patients in for an evaluation is either pain under the fibula, which is due to the fibula and the calcaneus (heel) impacting each other, and/or a callus or pressure point near the arch. Hopefully problems can be addressed before it gets to this point.
There is a lot to consider for a successful outcome and the specific considerations in this case are discussed in the blog.
The result, and goal, is a plantigrade foot, elimination of ankle pain and deformity, allowing for increased function. Physical therapy is an important component, as all patients with end-staged arthritis will compensate by externally rotation the limb in order to avoid a heel-to-toe as they transition in gait. Residual limb dysfunction, altered gait and mechanics need to be addressed in physical therapy, in order to maximize patient outcome.
