Subtalar Joint Pain – The Clinical Syndrome
Ankle and heel pain emanating from the subtalar joint is occasionally encountered in clinical practice. The subtalar joint is a synovial plane–type articulation between the talus and the calcaneus. Osteoarthritis of the subtalar joint is the most common form of arthritis that results in subtalar joint pain, although the joint also is susceptible to damage from rheumatoid and posttraumatic arthritis.
Most patients with subtalar joint pain secondary to osteoarthritis and posttraumatic arthritis pain report pain localized deep within the heel, with a secondary dull aching pain in the ankle. Activity, especially adduction of the calcaneus, makes the pain worse; rest and heat provide some relief. The pain is constant and characterized as aching; it 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 pain described, 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” secondary to adhesive capsulitis may develop.
What are the Symptoms of Subtalar Joint Pain
Examination of the ankle of patients with arthritis of the subtalar joint reveals diffuse tenderness to palpation. The ankle may feel hot to the touch, and swelling may be present. Adduction of the calcaneus and range of motion of the ankle exacerbate the pain. Weight bearing also may exacerbate the patient’s pain, and a hesitant, antalgic gait may be present. Crepitus may be present on range of motion of the joint.
How is Subtalar Joint Pain diagnosed
Plain radiographs are indicated in all patients with subtalar joint pain. Based on the patient’s clinical presentation, additional tests, including complete blood cell count, erythrocyte sedimentation rate, and antinuclear antibody testing, may be indicated. Arthrography, magnetic resonance imaging (MRI) of the subtalar joint, or both, is indicated if joint instability, occult mass, or tumor is suspected. Ultrasound imaging and computed tomography may provide additional information regarding the joint and help clarify the diagnosis.
Differential Diagnosis
The subtalar joint is susceptible to the development of arthritis from a variety of conditions that have in common the ability to damage the joint cartilage. Osteoarthritis is the most common cause, but rheumatoid arthritis and posttraumatic arthritis cause subtalar pain secondary to arthritis. Less common causes of arthritis-induced subtalar pain include collagen-vascular diseases, infection, and Lyme disease. Acute infectious arthritis usually is accompanied by significant systemic symptoms, including fever and malaise, and should be easily recognized by an astute clinician and treated appropriately with culture and antibiotics, rather than with injection therapy. The collagen-vascular diseases generally manifest as polyarthropathy rather than monoarthropathy limited to the subtalar joint, although subtalar pain secondary to collagen-vascular disease responds well to the intra-articular injection technique described subsequently. The subtalar joint may also develop pigmented villonodular synovitis.
Lumbar radiculopathy may mimic the pain and disability associated with arthritis of the subtalar joint. In such patients, the ankle examination findings should be negative. Entrapment neuropathies, such as tarsal tunnel syndrome, and bursitis of the ankle also may confuse the diagnosis; both conditions may coexist with arthritis of the subtalar joint. Primary and metastatic tumors of the distal tibia and fibula and spine and occult fractures also may manifest in a manner analogous to arthritis of the subtalar joint.
Treatment
Initial treatment of the pain and functional disability associated with arthritis of the subtalar joint should include a combination of nonsteroidal antiinflammatory drugs (NSAIDs) or cyclooxygenase-2 (COX-2) inhibitors and physical therapy. Local application of heat and cold may be beneficial. Avoidance of repetitive activities that aggravate the symptoms and short-term immobilization of the ankle joint also may provide relief. For patients who do not respond to these treatment modalities, an intra-articular injection of the subtalar joint with a local anesthetic and steroid may be a reasonable next step. Computed tomography (CT), fluoroscopic, or ultrasound guidance may be useful when performing injection of the subtalar joint if the anatomic landmarks are difficult to identify.
Complications and Pitfalls
Failure to identify primary or metastatic tumor of the ankle or spine that is responsible for the patient’s pain may yield disastrous results.
The major complication of intra-articular injection of the subtalar joint is infection. This complication should be exceedingly rare if strict aseptic technique is adhered to.
Approximately 25% of patients report a transient increase in pain after intra-articular injection of the subtalar joint, and patients should be warned of this possibility.
Clinical Pearls
Coexistent bursitis and tendinitis may contribute to ankle pain and may require additional treatment with more localized injection of a local anesthetic and depot steroid. Injection of the subtalar joint is extremely effective in the treatment of pain secondary to the causes of arthritis of the joint mentioned.
This technique is a safe procedure if careful attention is paid to the clinically relevant anatomy in the areas to be injected.
The use of physical modalities, including local heat and gentle range-of-motion exercises, should be introduced several days after the patient undergoes this injection technique for ankle pain. Vigorous exercises should be avoided because they would exacerbate the symptoms.
