The joint surfaces of the ankle (tibiotalar) and subtalar joints are prepared — cartilage is removed and bone surfaces freshened. A retrograde intramedullary nail is inserted through the heel (calcaneus), across both joint lines, and into the tibial shaft. Locking screws secure the nail proximally and distally. Bone graft is packed around the fusion sites. The nail provides immediate rigid fixation allowing earlier weight-bearing than screws or plates alone. The operation takes one and a half to two hours.
A hindfoot nail is recommended for combined ankle and subtalar arthritis, failed ankle replacement requiring conversion to fusion, talar AVN with collapse, Charcot neuroarthropathy of the ankle, and severe post-traumatic arthritis. It is the most powerful fixation method for hindfoot fusion.
Ankle-foot orthosis, custom footwear, pain management, and activity modification. Ankle replacement (if joint surfaces are salvageable) is a motion-preserving alternative. Isolated ankle or subtalar fusion (if only one joint is affected).
Weight-bearing X-rays and CT scan. Assessment of bone quality (particularly in Charcot patients). Vascular assessment in diabetic patients. Smoking cessation — fusion failure rates are dramatically higher in smokers.
Reliable pain relief and a stable, plantigrade foot. Union rates approximately 85–95% for the ankle joint and 90–95% for the subtalar joint. Most patients walk comfortably in supportive shoes with a rocker-bottom sole.
Loss of ankle and subtalar motionExpected
Expected — both joints are permanently fused.
Altered gaitExpected
Stiff ankle gait with reduced push-off. Walking on uneven ground is difficult.
Shoe limitationsExpected
Requires flat or rocker-bottom shoes.
Limb shorteningExpected
One to two centimetres from joint compression during fusion.
Non-unionUncommon
Risk approximately 5–15%. Higher in smokers, diabetics, and Charcot patients.
Wound healingCommon
The hindfoot skin is vulnerable, particularly in diabetic and vascular patients.
Nail prominenceCommon
The nail entry point at the heel may cause plantar discomfort.
Stress fractureUncommon
Above the nail tip.
Adjacent joint arthritisLong-term
Increased stress on the midfoot and knee.
InfectionUncommon
Deep infection around the nail.
General or spinal anaesthesia with nerve block.
Non-weight-bearing for six to eight weeks. Boot with progressive weight-bearing from eight to twelve weeks. Rocker-bottom shoes long-term. Physiotherapy for gait retraining and proximal strengthening. Full recovery six to twelve months.
X-rays at six weeks, three months, and six months. CT if non-union suspected.
Will I walk normally?
You will walk with a stiff ankle gait — shorter stride on the affected side and reduced push-off. Most patients walk comfortably for daily activities. Rocker-bottom shoes help. Running is generally not possible.
Why fuse both joints?
When both the ankle and subtalar joints are arthritic or destroyed (as in talar AVN or Charcot), fusing both provides the most reliable pain relief and stability. Fusing one joint in isolation when both are affected often leads to persistent pain.