Ankle arthritis

The ankle joint is subjected to more weight-bearing force per square centimeter and is more commonly injured than any other joint in the body, yet arthritis at the ankle it is roughly ten times less frequent than that at the knee and hip.

Around 75% of ankle osteoarthritis (OA) is secondary to trauma. This is in striking contrast to hip (8%) and knee (12.5%) OA. Most cases are a result of reoccurring outer (lateral) ankle sprains or a single ankle sprain with ongoing pain.

A very high percentage of ankle fractures result in ankle OA – the more severe the fracture the more likely OA will develop. When arthritic changes develop following an ankle fracture, they tend to be seen on x-rays within two years. On the other hand, an ankle free of arthritis at two years after treatment tends to remain so for at least another five to ten years.

The biggest risk factor for developing OA following injury is mal-alignment of the ankle. This changes the contact area of the forces acting on the ankle joint surfaces. Perhaps the most common cause of this is change of gait because of pain, fear of recurrence or habit developed as a result of the former. After a fracture, a malunited ankle fracture, poor surgical technique and malaligned bone setting are major risk factors.

The best outcomes are associated with minimal traumatic joint damage, early proper use and mobilization, anatomic reduction and a lack of complications (e.g. postoperative infection).

Prevention and treatment of ankle OA is based on an understanding of the primary role of mechanical forces acting on the ankle.