Intra-Articular Injection of the Subtalar Joint

Indications and Clinical Considerations

The subtalar joint is susceptible to developing arthritis from a variety of conditions that all have the ability to damage the joint cartilage. Osteoarthritis of the joint is the most common form of arthritis that results in subtalar joint pain. However, rheumatoid arthritis and posttraumatic arthritis also are common causes of subtalar pain secondary to arthritis. Less common causes of arthritis-induced subtalar pain include the collagen vascular diseases, infection, villonodular synovitis, and Lyme disease. Acute infectious arthritis is usually accompanied by significant systemic symptoms, including fever and malaise, and should be easily recognized by the astute clinician and treated appropriately with culture and antibiotics rather than injection therapy. The collagen vascular diseases generally manifest as a polyarthropathy rather than a monoarthropathy limited to the subtalar joint, although subtalar pain secondary to collagen vascular disease responds exceedingly well to the intra-articular injection technique described later.

The majority of patients with subtalar joint pain secondary to osteoarthritis and posttraumatic arthritis experience pain localized deep within the heel. Activity, especially adduction of the calcaneus, makes the pain worse; rest and heat provide some relief ( Fig. 175.1 ). The pain is constant and is characterized as aching and may interfere with sleep. Some patients report a grating or popping sensation with use of the joint, and crepitus may be present on physical examination.

In addition to the previously mentioned pain, patients with arthritis of the subtalar joint often experience a gradual decrease in functional ability with decreasing subtalar range of motion, making simple everyday tasks such as walking and climbing stairs quite difficult. With continued disuse, muscle wasting may occur and a “frozen subtalar joint” caused by adhesive capsulitis may develop.

Plain radiographs are indicated for all patients with subtalar joint pain. On the basis of the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, sedimentation rate, and antinuclear antibody testing. Magnetic resonance, computed tomography, and ultrasound imaging of the subtalar joint are indicated if joint instability, occult mass, or tumor is suggested ( Fig. 175.2 ).

Clinically Relevant Anatomy

The subtalar joint is a synovial plane-type articulation between the talus and calcaneus ( Figs. 175.3 and 175.4 ). The articular surface is covered with hyaline cartilage, which is susceptible to arthritis. The joint is surrounded by a dense capsule, which helps strengthen the subtalar joint. The joint capsule is lined with a synovial membrane that attaches to the articular cartilage. The major ligaments of the subtalar joint include the medial and lateral talocalcaneal ligaments and the interosseous ligament, which provide the majority of strength to the subtalar joint ( Fig. 175.5 ). The muscles of the subtalar joint and their attaching tendons are susceptible to trauma and to wear and tear from overuse and misuse.