Ankle Arthrodesis

Indication. End-stage tibiotalar (ankle) osteoarthritis — pain, stiffness and progressive loss of function — that has failed a minimum of 3–6 months of conservative care (NSAIDs, physiotherapy, an intra-articular corticosteroid injection and an ankle-foot orthosis). The arthritis may be primary, post-traumatic (the commonest cause, for example after a pilon or ankle fracture treated by ORIF), rheumatoid, Charcot neuroarthropathy, or the result of a failed total ankle replacement. Assess the whole hindfoot before committing. Confirm the disease is isolated to the tibiotalar joint, because concomitant disease changes the plan: - Examine the subtalar and midfoot joints clinically — symptomatic subtalar arthritis may require a tibiotalocalcaneal (TTC) fusion rather than an isolated ankle fusion.

• Obtain a weight-bearing AP and lateral radiograph and a CT to characterise the deformity, assess bone stock and the subtalar joint, and identify retained metalwork that may need removal.
• Gauge deformity magnitude and talar vascularity — arthroscopic fusion is reliable only when coronal/sagittal deformity is minimal (generally less than 15°) and there is no talar avascular necrosis. Absolute indications - End-stage tibiotalar osteoarthritis (primary, post-traumatic, or rheumatoid) with failed conservative management.
• Tibiotalar arthritis following failed ORIF with joint destruction.
• Charcot neuroarthropathy of the ankle with instability or ulcer risk.
• Ankle instability with severe arthritis, or arthritic change after failed ligamentous reconstruction.
• Failed total ankle replacement with inadequate bone stock for revision TAR. Relative indications - Avascular necrosis of the talus with joint involvement.
• Septic arthritis with residual tibiotalar destruction (staged — eradicate infection, then fuse).
• Ankle tumour resection requiring reconstruction with fusion.
• Severe coronal or sagittal deformity not correctable by realignment osteotomy alone. Contraindications - Active deep infection (relative — a staged approach is possible).
• Severe ipsilateral hindfoot or midfoot arthritis limiting compensatory motion.
• Contralateral lower-limb amputation (fusion prevents compensatory gait adaptation).
• Unrealistic patient expectations regarding functional outcome. The one decision that matters — choose the approach. Every ankle fusion prepares the joint and fixes it in the same four-point position; what differs is the exposure and fixation:

A motion-preserving total ankle replacement is the alternative for the older, low-demand patient with preserved subtalar motion, near-normal alignment and good bone stock — the fusion-versus-TAR decision is covered under Background & Evidence. Consent specifically for sural or superficial peroneal numbness/dysaesthesia, anterior wound problems (especially in diabetes and Charcot), non-union (about 5–10%, higher if smoking continues), malposition requiring revision, accelerated adjacent-joint arthritis over decades, and CRPS. Setup. Supine with a sandbag under the ipsilateral hip to bring the foot into neutral rotation, a padded thigh tourniquet, and the image intensifier on the contralateral side for unobstructed AP and lateral views. Mark the superficial peroneal nerve (tense it with plantarflexion and inversion), the dorsalis pedis pulse, and both malleoli before inflating the tourniquet.

The goal is to expose the tibiotalar joint, remove all residual cartilage to bleeding cancellous bone on both surfaces, correct any deformity by differential bone resection, fix the joint in the four-point position, and graft any defects. The exposure — arthroscopic portals or the open anterior/transfibular approach — is laid out as the first operative steps below.

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Rehabilitation | Phase | Timing | Immobilisation & weight-bearing | Milestones | |-------|--------|--------------------------------|------------| | 1 | 0–2 weeks | Below-knee backslab, strict non-weight-bearing, elevation above heart level for 48–72 h | Wound check at 48–72 h; drain out at 24–48 h | | 2 | 2–6 weeks | Circumferential below-knee cast; remain non-weight-bearing (Charcot with a nail: protected weight-bearing in a total contact cast from week 2) | Suture removal at 2 weeks | | 3 | 6–12 weeks | CAM boot with progressive weight-bearing if radiographs show bridging; full weight-bearing in the boot by 8–10 weeks | Boot-to-shoe transition at 10–12 weeks; CT at 12 weeks if union uncertain | | 4 | 3–6 months | Supportive footwear with a custom orthosis for the first 6 months | Driving at about 12 weeks; sedentary work 6–8 weeks; light manual 12–16 weeks; heavy manual about 6 months; low-impact sport 4–6 months | Because the ankle is fused, rehabilitation focuses on hip and knee strengthening, balance and proprioception (eyes-closed single-leg stance) and gait retraining, not ankle range of motion. A popliteal nerve block gives 12–24 hours of effective analgesia and reduces early opioid requirements. Union assessment. Declare union when at least three cortices are bridged on plain radiograph, the fusion site is pain-free on stress, and the patient is progressing to full weight-bearing. CT at 12 weeks is the gold standard when the radiograph is equivocal — plain films significantly underestimate non-union. Follow up at 2 weeks (wound), 6 weeks (radiograph and weight-bearing decision), 12 weeks (CT if union uncertain, boot-to-shoe), 6 months (final union, orthosis review) and 12 months, then annually to screen adjacent joints. Review urgently for increasing pain and swelling beyond the expected course, wound breakdown or discharge, worsening neurology, or hardware failure on radiograph. Complications

Background. End-stage tibiotalar osteoarthritis is most often post-traumatic — after an intra-articular pilon or ankle fracture treated by ORIF — and less often primary, rheumatoid, haemophilic, Charcot, or the result of a failed total ankle replacement. The tibial plafond is slightly wider anteriorly and the talar dome is trapezoidal (wider anteriorly), which is why the dome is unconstrained in plantarflexion and relevant to how the joint surfaces are prepared; the mechanical axis of the tibia lies about 3° of valgus relative to the anatomical axis, informing the desired fusion position. Arthroscopic versus open — the key evidence. Three series establish the arthroscopic technique and its limits. Ogilvie-Harris (1993) reported 19 arthroscopically assisted fusions in ankles with minimal or no deformity fixed with three percutaneous cannulated screws; 17 of 19 united (2 non-unions), with excellent or good results in 16 — establishing the technique for non-deformed arthritic ankles. Zvijac (2002) reported 21 arthroscopically assisted fusions with 20 of 21 (95%) united at a mean of 8.9 weeks, the single failure having extensive talar avascular necrosis (approximately half the talus) — reinforcing AVN and deformity as relative contraindications. Townshend (2013), the comparative benchmark, studied 60 patients (30 arthroscopic, 30 open) over 2 years: both groups improved significantly in the Ankle Osteoarthritis Scale and SF-36 physical component, with significantly greater early improvement and a shorter hospital stay in the arthroscopic group and similar complications, operative time and radiographic alignment. Current recommendation: arthroscopic arthrodesis is preferred for end-stage OA without significant deformity (less than 15°) or talar AVN; open technique is required for major deformity correction, Charcot, bone loss requiring graft, or revision. Long-term outcomes — the price of a successful fusion. Coester (2001) followed 23 patients with isolated post-traumatic ankle arthrodesis a mean of 22 years (the longest follow-up reported) and found ipsilateral subtalar, talonavicular, calcaneocuboid, naviculocuneiform, tarsometatarsal and first MTP arthritis all significantly more severe than the contralateral side (each p less than 0.01), with worse activity limitation, pain and disability — the knee was not significantly affected. Hendrickx (2011) reported 60 patients (66 ankles) fused with a two-incision, three-screw technique: 91% primary union (six required re-arthrodesis), mean AOFAS 67 and 91% satisfaction at a mean 9 years, with significant radiographic progression of arthritis in all adjacent joints. This accelerated adjacent-joint degeneration is the central argument for offering motion-preserving TAR to suitable candidates.

Total ankle replacement and tibiotalocalcaneal references 1. Saltzman CL, Mann RA, Ahrens JE, et al. Prospective controlled trial of STAR total ankle replacement versus ankle fusion: initial results. Foot Ankle Int. 2009;30(7):579–596. PMID 19589303. Non-randomised multicentre controlled (concurrent fusion controls) non-inferiority trial; equivalent pain relief and better function with STAR TAR at 24 months, with more secondary procedures. 2. Clough TM, Ring J. Total ankle arthroplasty. Bone Joint J. 2021;103-B(4):696–703. PMID 33789488. Single-centre series of 118 Zenith TAAs with 88% implant survival at 7 years, comparable to National Joint Registry data. 3. Myerson MS, Alvarez RG, Lam PW. Tibiocalcaneal arthrodesis for the management of severe ankle and hindfoot deformities. Foot Ankle Int. 2000;21(8):643–650. Technique description and outcomes for tibiotalocalcaneal arthrodesis using retrograde intramedullary nailing for complex hindfoot pathology including Charcot arthropathy.