Subtalar arthritis is characterized by pain in the hindfoot that is aggravated by standing and walking particularly on uneven ground. It is likely to be associated with stiffness moving the foot from side to side. The most common cause of subtalar arthritis is a previous injury – usually a calcaneal fracture. Non-operative treatment involves limiting the movement and loading through the subtalar joint by wearing comfort shoes, bracing, and weight control; decreasing standing and walking particularly on uneven terrain; and possibly taking anti-inflammatory medications or receiving corticosteroid injections to improve pain control. Surgery is indicated for subtalar arthritis that has failed non-operative treatment. Fusion of the subtalar joint is the most predictable surgical option as it turns a stiff painful joint into a stiff painless joint.
Clinical History: Subtalar Arthritis
Patients with subtalar arthritis will complain of pain in their “ankle” and hindfoot. The pain is actually from the joint immediately below the ankle joint – the subtalar joint. This joint is largely responsible for allowing the foot to accommodate to uneven terrain by moving the hindfoot from side to side (inversion and eversion). This is why a patient’s symptoms are often aggravated by walking on uneven terrain.
Most subtalar arthritis is caused by a previous trauma, usually a calcaneal fracture, although certain fractures involving the talar body may also cause subtalar arthritis. Other causes include repetitive abnormal loading of the subtalar joint due to a tarsal coalition or misalignment of the hindfoot due to a chronic flatfoot or high arched foot. Rheumatoid arthritis may also produce subtalar arthritis.
On examination patients with subtalar arthritis will usually have noticeable stiffness in their hindfoot (limited motion moving the foot side to side). They will also often have a deep seated pain below the ankle joint. There may also be swelling on the outside of the hindfoot.
Imaging Studies: Subtalar Arthirtis
X-rays will reveal a loss of the subtalar joint space which is best seen on a lateral view of the foot taken with the patient bearing weight (Figure 1).
Figure 1- Subtalar Arthritis
A CT scan or MRI is sometimes indicated to identify the extent of the arthritis and to determine if there is any other source of pain (ex. ankle arthritis, posterior tibial tendonitis, peroneal tendonitis, etc.)
Occasionally a diagnostic injection of local anesthetic (ex. lidocaine) will be performed to get some sense of how much pain is originating from the subtalar joint. This is usually done with fluoroscopy (mini x-ray) or CT scan to ensure that the injection is accurately placed. The lidocaine will only last a few hours and when it wears off the pain may actually be worse for a short while. However, if immediately after the injection the patient has a significant relief of pain for a few hours this suggests that most of the symptoms are coming from the area that was injected – in this case the subtalar joint.
Non-operative treatment focuses on limiting the amount of loading and movement at the subtalar joint and by masking the pain. Non-operative treatment involves some trial and error on the part of the patient to see what strategies are most effective. Non-operative treatments include:
- Activity Modification: Limiting standing and walking particularly on uneven terrain will help limit exacerbation of symptoms from subtalar arthritis. Use of an exercise bike of swimming as a form of aerobic exercise instead of walking or running will likely be beneficial as it allows for a good workout with much less loading through the subtalar joint.
- Weight-Loss: The back part of the foot is subject to forces equivalent to 3-5x body weight during daily activities so losing even a moderate amount of weight can substantially decrease the forces going through the arthritic joint.
- Comfort Shoes: Use of comfort shoes including adding a shock absorber in the heal can help decrease the repetitive loading through the subtalar joint.
- Ankle Bracing: Use of an ankle brace such as an ankle lacer or even taping the ankle and hindfoot can be helpful because it serves to limit motion through the arthritic subtalar joint.
- Icing and Elevation after Activity: Elevating the leg and placing a bag of ice around the ankle and hindfoot after activity can help to decrease pain and swelling. Ice should only be applied for 10-15 minutes at a time.
- Anti-inflammatory medication (NSAIDs): If there are no contra-indications NSAIDs can help decrease a patient’s arthritis symptoms
- Tylenol: Plain Tylenol (acetaminophen) taken 2-3 times a day can help reduce the pain from subtalar arthritis. It may not be as effective as anti-inflammatory medications (NSAIDs) but it works via a different mechanism so it may have an additive effect. It should not be taken by anyone with liver problems
- Glucosamine Sulfate: Although it has not been shown to be beneficial in long-term studies many people report improved symptom control when they take glucosamine sulfate. It needs to be taken daily for 6-8 week for any benefit to be seen.
- Corticosteroid Injections: Pain relief from corticosteroid injections will tend to be temporary.
- Hylauronic Acid Injections (HA): Injections of HA have shown some success in the knee joint, but the results in the subtalar joint has not been demonstrated.
- Self-Administered strengthening and stretching programs: Exercise to keep the muscles of the foot as strong as possible and to keep the joint moving through a gentle range of motion may be helpful.
Operative treatment is usually reserved for extensive subtalar arthritis that has failed non-operative management. Occasionaly patients will be noted to have an isolated area of damage to the subtalar joint or a loose body which can addressed by cleaning out (debriding) the subtalar joint either arthroscopically or more commonly by opening the joint. However, in most instances patient with subtalar arthritis have lost significant cartilage and need to have the subtalar joint fused (Figure 2).
Figure 2: Subtalar Fusion
A subtalar fusion is not to be confused with a subtalar arthroresis (placing a plug in the subtalar joint) which is not appropriate for treating subtalar arthritis.
- Subtalar Fusion (Arthrodesis): Fusing the subtalar joint is an effective treatment option for patients with significant subtalar arthritis that has failed non-operative management. The procedure takes a painfully stiff subtalar joint and turns it into a non-painful stiff joint. A subtalar fusion is performed by cleaning out the remnants of cartilage from the joint and putting screws and bone grafts across the joint.
Edited by Paul Juliano MD December 12, 2012