Ankle synovitis is a condition characterized by inflammation of the soft tissue lining the ankle joint capsule, known as the synovium, with subsequent ankle swelling, pain and stiffness.
The lower leg comprises of 2 long bones, known as the fibula and the tibia, which are situated beside each other (figure 1). These bones join with each other and the talus to form the ankle joint (figure 1). The ankle joint comprises of strong connective tissue surrounding the joint known as the joint capsule. The joint capsule is lined with specialized tissue known as the synovium (or synovial membrane) which is responsible for secreting lubricating fluid (synovial fluid) into the ankle joint, therefore reducing friction during ankle movements.
Patients with ankle synovitis typically experience an ache or pain at the front and / or sides of the ankle. Occasionally pain may be felt in the back of the ankle. Symptoms may develop suddenly due to a specific incident or gradually over time. Most commonly, ankle synovitis will present following an ankle sprain that does not fully recover and causes ongoing pain, swelling, stiffness and difficulty with weight bearing.
Symptoms are typically worse in the morning (or with rest following weight bearing activity) and may present as pain and stiffness that slowly improves as the patient warms up (e.g. following a morning shower). Symptoms may also be aggravated during walking or running especially on slopes or on uneven surfaces. The patient may also experience swelling as well as tenderness on firmly touching the ankle joint.