Surgical Management

1. Indications for Surgery

Surgery in Charcot is reserved for problems that conservative management cannot solve. The accepted indications (consensus IWGDF, AOFAS, Pinzur):

• Recurrent or non-healing plantar ulceration over a bony prominence (most often a midfoot rocker-bottom apex).
• Severe, rigid, non-braceable deformity — cannot be accommodated in CROW or custom footwear.
• Gross instability — especially Brodsky 3A ankle Charcot with progressive talar collapse or dislocation; the limb is at imminent risk.
• Failure of conservative management — after at least 6–12 months of adequate offloading, with persistent hyperaemia or progressive deformity.
• Concurrent osteomyelitis requiring debridement, often combined with reconstruction.

Surgery during active (Stage 0–I) Charcot was historically taboo because of the perception that osseous fixation in actively resorbing bone was doomed to fail. The modern view (Pinzur, Sammarco, Mittlmeier) is more nuanced: in carefully selected cases of severe instability, early surgical stabilisation may shorten the active phase by mechanically arresting the cascade. This remains the most controversial timing decision in CN surgery.

2. Pre-operative Optimisation

The Charcot patient is, by definition, a high-risk surgical candidate. A checklist of pre-operative optimisation is essential:

• Glycaemic control — HbA1c <8% (ideally <7.5%); chronic hyperglycaemia is associated with infection and non-union.
• Vascular assessment — pulses, ABI/TBI, TcPO₂; revascularisation if indicated before reconstruction.
• Nutritional assessment — albumin, prealbumin, lymphocyte count; correct deficiencies.
• Smoking cessation — non-union rate ~3× in active smokers; ideally >6 weeks pre-op.
• Renal function — ESRD on dialysis is associated with high complication rates; coordinate with nephrology.
• Cardiac evaluation — especially given the strong association of diabetic neuropathy with autonomic and ischaemic heart disease.
• Skin condition — address any open wounds, debride callus, ensure no active cellulitis.
• Bone biopsy — rule out occult osteomyelitis if there is concurrent ulcer.
• Bone health — consider DEXA, vitamin D repletion, calcium, possibly anti-resorptive optimization.

Patients who cannot be optimised — uncontrollable HbA1c >10%, uncorrectable ischaemia, gangrene, refractory osteomyelitis — are often better served by primary below-knee amputation (BKA) than by attempted reconstruction. This is an honest discussion to have early. BKA with appropriate prosthetic rehabilitation in a motivated patient gives superior functional outcomes than a salvaged but non-functional foot.

3. Exostectomy — The Simplest Operation

Exostectomy is the resection of a bony prominence, most commonly the plantar apex of a midfoot rocker-bottom Brodsky type 1 deformity. It is the simplest CN reconstructive operation and often the only one needed when the foot is otherwise stable.

Indications:

• Stable Stage III foot with isolated plantar prominence and recurrent ulceration over it.
• Medial or lateral column prominence in a braceable foot.
• Calcaneal exostosis in a Brodsky 3B avulsion deformity.
• Patient unsuitable for major reconstruction.

Technique: medial or lateral approach (avoiding direct plantar incision through ulcerated skin); subperiosteal exposure; ostectomy with osteotome, saw, or burr; careful smoothing; layered closure; non-weight-bearing 4–6 weeks. Post-operative TCC for 6–8 weeks, then transition to accommodative footwear or CROW.

Outcomes: ulcer healing in ~75–90%, recurrence over 5 years ~15–30% (Catanzariti et al., JFAS 2000; Brodsky and Rouse, Foot Ankle Int 1993). The procedure does not address underlying instability and does not prevent re-deformity in feet that are still actively progressing. For a Brodsky type 1 stable midfoot Charcot with a single rocker prominence, it is often the right operation; for a Brodsky 3A ankle Charcot with instability, it is inadequate.

4. Achilles Tendon Lengthening (TAL) / Gastrocnemius Recession

The equinus contracture of long-standing diabetes drives forefoot/midfoot peak plantar pressure (Part III) and is mechanistically central to ulceration. Lengthening the Achilles or gastrocnemius is therefore a powerful biomechanical adjunct.

• Percutaneous triple-hemisection TAL (Hoke procedure) — three half-cuts of the Achilles in a sliding pattern, allowing the tendon to lengthen 1–2 cm under tension; 5–10 minute outpatient procedure.
• Open Z-lengthening — greater control of length but more morbidity.
• Strayer / Vulpius gastrocnemius recession — more proximal release of gastrocnemius alone; preserves soleus strength.

Mueller et al. (J Bone Joint Surg Am 2003) demonstrated that percutaneous TAL added to TCC in neuropathic forefoot ulcers reduced recurrence at 2 years from ~80% (TCC alone) to ~30% (TCC + TAL). The parallel benefit in CN is biomechanical: reducing forefoot/midfoot push-off forces unloads the apex of midfoot rocker-bottom deformity. TAL is a routine adjunct in midfoot CN reconstruction.

Caveat: over-lengthening → calcaneal gait, heel ulceration. The TAL must be calibrated; over-correction in an already neuropathic foot is a recognised complication. Intra-operative passive ankle dorsiflexion to ~5° with knee extended (Silfverskiöld test) is the standard end-point.

5. Midfoot Arthrodesis — Realignment for Brodsky Type 1

Midfoot arthrodesis — fusion of the tarsometatarsal and naviculocuneiform joints — is the definitive operation for severe, non-correctable, ulcer-prone Brodsky type 1 (midfoot) Charcot. The goal is a plantigrade, stable, braceable foot: one in which the heel and metatarsal heads sit at the same plane and the load is distributed across the entire plantar surface rather than concentrated on a midfoot apex.

Surgical principles:

• Realignment osteotomy — corrective osteotomies at the apex of deformity to restore Meary’s line.
• Joint preparation — removal of articular cartilage, drilling / fishscaling subchondral bone for vascular ingrowth.
• Bone grafting — autograft (iliac crest), allograft, or rhBMP-2 to fill defects from previous bone loss.
• Rigid fixation — intramedullary beaming with axial screws across the medial / central / lateral columns; or plating; or external fixation.
• Achilles lengthening — routine adjunct.
• Prolonged non-weight-bearing — 12–16 weeks minimum; sometimes 6 months.

The intramedullary beam technique (Sammarco; Marks et al., Foot Ankle Int 2003): fully threaded 7.0–7.5 mm cannulated screws are placed retrograde from the metatarsal heads across the corrected midfoot into the talus or calcaneus, providing long-segment intramedullary stability resistant to the bending forces of gait. Two or three columns are typically beamed; the medial column is essential.

Outcomes: union rates 65–85% in modern series; ulcer-free survival at 5 years 65–80% with appropriate footwear; functional limb salvage rate 80–95%. Beam constructs perform better than locking-plate constructs in comparative series, especially in osteopenic Charcot bone where plate fixation tends to pull out (Wukich et al., JFAS 2014).

6. Hindfoot & Ankle Arthrodesis — TTC Fusion

Brodsky type 2 (hindfoot/Chopart) and especially type 3A (tibiotalar) Charcot are the most challenging surgical patterns. Instability tends to progress; the foot is at risk of frank dislocation; the limb is at risk of amputation. The standard reconstruction is tibiotalocalcaneal (TTC) arthrodesis with retrograde intramedullary nail.

Technique:

• Lateral or anterior approach to ankle/subtalar; debridement of cartilage and necrotic bone; correction of deformity.
• Bone grafting of defects (iliac crest autograft, structural allograft, femoral-head allograft, or rhBMP-2 for compromised hosts).
• Plantar entry retrograde nail (10.5–11.5 mm diameter, 250–300 mm length) inserted through the calcaneus, across the subtalar joint, into the talus and tibia.
• Compression at the fusion sites via the nail’s integral compression mechanism; locking screws proximal and distal.
• Adjunctive plates or external fixation when nail alone is insufficient (deformity, bone loss).
• Non-weight-bearing 12–16 weeks; protected ambulation 16–24 weeks.

Outcomes (Pinzur, J Bone Joint Surg Am 2007; Caravaggi et al., JFAS 2012; Pelton et al., Foot Ankle Int 2006): union rates ~70–85% in best series; limb salvage 80–90%; ambulation with brace at 1 year in ~75–85%. Stress-fracture / nail breakage above the proximal locking screws is a recognised complication, often related to early weight-bearing.

For the Brodsky 3B calcaneal avulsion, acute repair with screws and bone graft (or excision of the avulsion and advancement of the Achilles) is performed when the avulsion is recent; chronic cases often need TTC fusion plus calcaneal reconstruction.

7. Internal vs External Fixation

The fixation choice is one of the most-debated decisions in CN surgery:

External fixation (Ilizarov ring fixator) has a special place in CN. The classical Ilizarov principles — circular frame with crossing K-wires; gradual deformity correction; biology-respecting fine-wire stabilisation — suit the infected, deformed, osteopenic CN foot. The frame stays on for 3–6 months; the patient is allowed partial weight-bearing through the frame; pin sites are inspected and cared for daily. Outcomes from experienced centres (Wukich, Pinzur) report limb-salvage rates of 80–95% in feet that would otherwise face amputation.

The pragmatic algorithm in 2026 is roughly: internal fixation (beam & screws or retrograde nail) for elective Stage III reconstructions in clean, vascularised feet; external fixation for active infection, ulceration, severe deformity, or salvage of failed internal fixation; combined for the most compromised hosts (e.g., transplant recipients with prior failed surgery).

8. The Super-Construct Principle

Sammarco (Foot Ankle Clin 2009; Superconstructs in the treatment of Charcot foot deformity: plantar plating, locked plating, and axial screw fixation) articulated four principles — the “super-construct” principles— that have shaped the modern surgical approach to Charcot:

1. Extend the fusion beyond the zone of injury — into bone of normal quality on both sides. Don’t end the construct in the middle of the resorbing bone.
2. Resect bone to shorten the limb / correct deformity adequately — achieve plantigrade alignment; cosmetics can wait.
3. Use the strongest device possible — full-thread beam screws, locking plates, intramedullary nails. Charcot bone is osteopenic and dynamic; under-fixation fails.
4. Place the device in the most biomechanically advantageous position — intramedullary, plantar (tension-side), or both.

These principles deliberately depart from standard arthrodesis dogma (preserve length, fix to subchondral bone, etc.). In Charcot, the bone is not normal; standard biomechanics will not hold. The super-construct acknowledges the disease.

Practical implications:

• A midfoot Charcot reconstruction often spans from cuneiform/cuboid to metatarsal head — not just one joint — with beams crossing through normal bone proximally and distally.
• A TTC fusion often extends fixation up the tibial diaphysis well above the zone of injury.
• Plantar tension-side plating — biomechanically superior to dorsal plating in midfoot fusion — resists the dorsiflexing forces of gait.
• Locked screws are essential; non-locked screws strip in osteopenic bone.

The super-construct concept has been the most influential single contribution to the surgical literature on CN of the past 20 years.

9. Complications & Salvage

CN reconstruction is, even in expert hands, a high-complication operation. Realistic expectations:

• Non-union — 15–30% in midfoot, 20–40% in TTC. Often a “stable fibrous union” that is functionally adequate.
• Hardware failure — broken screws, plates pulling out, IM nail breakage above proximal lock; reported 10–25%.
• Infection — superficial 10–20%, deep 5–15%; higher with concurrent ulcer or osteomyelitis.
• Wound dehiscence — common; requires meticulous soft-tissue handling.
• Recurrent deformity — 10–20%, especially with inadequate fixation.
• DVT / PE — given the prolonged immobilisation; chemoprophylaxis routine.
• Major amputation — 5–15% over 5 years, depending on series and patient selection.

Salvage of failed reconstruction includes: revision arthrodesis, conversion to ring fixator, conversion to a different fixation strategy, and ultimately below-knee amputation (BKA). BKA in a patient with multiply-failed reconstructions is not a defeat; it is sometimes the rational endpoint that gives the best functional outcome.

The key counselling point with patients before any major reconstruction: the goal is a plantigrade, ulcer-free, braceable foot, not a normal foot. Patients who understand this enter surgery with realistic expectations, are happy with imperfect-but-functional outcomes, and avoid chasing repeated revisions for cosmetic concerns. Long-term outcome and prevention of contralateral CN are the subject of Part VIII.