What is hindfoot arthritis?
The hindfoot connects the leg at the ankle joint to the midfoot, and acts to provide a stable foundation for supporting body weight during standing, walking and running. It consists of the subtalar, talonavicular and calcaneocuboid joints, and is responsible for allowing sideway movement and contributing to some of the up and down motion of the foot. Hindfoot arthritis is usually a degenerative condition where the lining or cartilage of the aforesaid joints wears away, causing pain, stiffness, swelling and/or deformity. Malalignment of the ankle or foot, such as with a flatfoot or pes planovalgus deformity, can result in abnormal loading through the larger joints at the back of the foot and also lead to hindfoot arthritis with time. Alternatively, arthritis in the hindfoot, in particular the subtalar joint, can likewise be a sequela of previous trauma or injury, such as from an intra-articular (involving the joint) fracture of the calcaneum or heel bone.
What are the symptoms of hindfoot arthritis?
Patients with hindfoot arthritis normally present with pain, stiffness and swelling at the back of their foot, and may have an associated flatfoot deformity which can progress over time. They typically localise the pain to over the lateral aspect or top of their hindfoot, or below their ankle, which is worse when they walk on uneven ground. They may also describe pain and stiffness in the morning, on startup or after prolonged inactivity.
How can hindfoot arthritis be managed?
Non-operative management strategies for hindfoot arthritis include wearing cushioned stiff or rocker sole shoes with medial arch support, using a medial arch support orthotic, losing and maintaining a healthy weight, activity modification by avoiding activities which aggravate your symptoms and by preferencing low impact-loading activities for exercise/recreation in the long term, such as swimming, cycling and Pilates, simple over-the-counter oral analgesia and/or oral/topical anti-inflammatory medication if not contraindicated as required, and/or image-guided intra-articular corticosteroid and local anaesthetic injections to the affected joints. The aim of a steroid injection is to try neutralise any chronic inflammation and provide pain relief however, this can be variable and often temporary in effect. Patients may similarly benefit from physical therapy or prehabilitation focusing on calf, ankle and foot range of motion and stretching exercises, and general conditioning and strengthening of their lower limbs to optimise their pre-operative baseline, including exercising in the swimming pool or doing hydrotherapy.
What is the surgical treatment for hindfoot arthritis?
Definitive surgical treatment of hindfoot arthritis involves performing an arthrodesis or fusion of the subtalar, talonavicular and/or calcaneocuboid joint, and may require simultaneous correction of any associated flatfoot deformity or fracture-malunion. Fusing a major joint, such as in the hindfoot, requires excision of the arthritic joint surfaces, grafting the fusion site with bone graft (usually a combination of your own bone or autograft harvested from your ankle, knee or hip area, and allograft which is processed bone from another human), then joining the hindfoot bones with screws, staples and/or a plate.
What is the recovery after a hindfoot fusion?
After your hindfoot arthrodesis, you will be non-weight-bearing through your operated foot for 8 weeks, and can then gradually progress from partial to full weight-bearing over another 8 weeks. You will be immobilised in a below-knee plaster backslab/fibreglass cast for 8 weeks, and can then transition to a CAM boot with a medial arch support orthotic. You will need to wear your CAM boot when ambulating only for this subsequent 8 weeks. It can take 3-4 weeks for your wounds to heal, 6-7 months for your hindfoot fusion to unite, 7-8 months before you feel reasonably comfortable walking in cushioned sole normal supportive shoes, and at least 12 months for the swelling in your hindfoot to subside and for full recovery to your new baseline level.
What restrictions will I have after fusion of my hindfoot?
Once your hindfoot arthrodesis has united, there should be significant improvement of the arthritic pain in your hindfoot compared to pre-operatively. In addition, the shape of your foot should be noticeably better if the indication for your surgery was to correct a fixed deformity or previous associated fracture-malunion. With regard to mobility, a hindfoot fusion theoretically reduces the sideway and some of the up and down movement of the foot. However, this is usually well tolerated, as patients with advanced hindfoot arthritis and/or a flatfoot typically have pre-existing restricted movement. The metalware used to arthrodese your hindfoot does not need to be removed unless it causes a problem, such as irritation from prominence.