The ankle joint, which is also known as the tibiotalar or talocrural joint, is a synovial hinge-type joint, which allows dorsiflexion and plantar flexion. The joint is comprised of three bones: (1) the tibia, (2) the fibula, and (3) the talus (Fig. 154.1). The joint’s articular cartilage is susceptible to damage, which, left untreated, will result in arthritis with its associated pain and functional disability. Osteoarthritis of the joint is the most common form of arthritis that results in ankle joint pain and functional disability, with rheumatoid arthritis and posttraumatic arthritis also causing arthritis of the ankle joint. The joint is the most commonly injured joint in the human body, with sports injuries from basketball, football, tennis, and cross-country running being frequent causes of pain and functional disability. Less common causes of arthritis-induced ankle joint pain include the collagen vascular diseases, infection, villonodular synovitis, and Lyme disease. Acute infectious arthritis of the ankle joint is best treated with early diagnosis, with culture and sensitivity of the synovial fluid, and with prompt initiation of antibiotic therapy. The collagen vascular diseases generally manifest as a polyarthropathy rather than a monoarthropathy limited to the ankle joint, although ankle pain secondary to the collagen vascular diseases responds exceedingly well to ultra-sound-guided intra-articular injection of the ankle joint.

Patients with ankle joint pain secondary to arthritis and collagen vascular disease-related joint pain complain of pain that is localized to the ankle joint and distal lower extremity. Activity, especially involving dorsiflexion of the ankle joint, makes the pain worse, with rest and heat providing some relief. The pain is constant and characterized as aching. Sleep disturbance is common with awakening when the patient rolls over onto the affected ankle. Some patients complain of a grating, catching, or popping sensation with range of motion of the joint, and crepitus may be appreciated on physical examination.

Functional disability often accompanies the pain associated with many pathologic conditions of the ankle joint. Patients will often notice increasing difficulty in performing their activities of daily living, and tasks that require walking, climbing stairs, and walking on uneven surfaces are particularly problematic. If the pathologic process responsible for the patient’s pain symptomatology is not adequately treated, the patient’s functional disability may worsen, and muscle wasting may occur.

Plain radiographs are indicated in all patients who present with ankle pain as not only intrinsic ankle disease, but also other regional pathology may be perceived as ankle pain by the patient (Fig. 154.2). Based on the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. Magnetic resonance imaging, computed tomography, or ultrasound of the ankle joint is indicated if avascular necrosis or ligamentous injury is suspected or if the diagnosis is unclear (Fig. 154.3).

The tibia and fibula articulate with the talus at the ankle joint (see Fig. 154.1). The articular surface is dome shaped and referred to as the mortise. The articular surfaces are covered with hyaline cartilage, which are susceptible to arthritis. The joint is completely surrounded by a dense capsule that provides support to the joint. The majority of strength to the ankle joint is provided by the major ligaments, which include the deltoid, anterior talofibular, calcaneofibular, and posterior talofibular ligaments (Fig. 154.4). The joint capsule is lined with a synovial membrane that attaches to the articular cartilage and may give rise to bursae. The tibiofibular joint is innervated by the deep peroneal and tibial nerves. In addition to arthritis, the ankle joint is susceptible to the development of tendonitis and bursitis and disruption of the ligaments, cartilage, and tendons.