Tarsometatarsal (TMT) Arthrodesis - Isolated or Multi-Ray

Indication. Symptomatic tarsometatarsal (Lisfranc) arthritis - midfoot pain on weight-bearing with deformity and functional limitation - that has failed conservative management (stiff-soled or rocker-bottom shoes, custom orthotics, activity modification, NSAIDs and intra-articular corticosteroid injection). The decision to operate is always preceded by weight-bearing radiographs and a CT to map every arthritic joint, because the whole strategy turns on fusing the right rays and preserving the mobile ones. The five indications, in order of frequency. - Post-traumatic arthritis (most common). High-energy Lisfranc injuries damage articular cartilage and the stabilising ligaments, and arthritis develops in 30-50% of cases, typically presenting 12-24 months after injury with persistent medial midfoot pain, deformity and loss of function despite good initial reduction.

• Primary degenerative osteoarthritis. Idiopathic TMT arthritis most often affects the 1st-2nd TMT joints, producing medial column collapse, an acquired flatfoot, metatarsalgia and callus under the 2nd-3rd MT heads, and difficulty with shoe wear.
• Inflammatory arthropathy. Rheumatoid, psoriatic and seronegative spondyloarthropathies cause synovitis, erosions and progressive multi-ray deformity, often needing more extensive fusion because of panarticular involvement.
• Failed Lisfranc ORIF. Hardware failure, loss of reduction or symptomatic post-traumatic arthritis after fixation is converted to arthrodesis, usually with hardware removal at the same sitting.
• Adult-acquired flatfoot (stage 3-4). Advanced posterior tibial tendon dysfunction produces midfoot break, abduction and medial column instability; TMT arthrodesis corrects deformity and stabilises the column when isolated reconstruction is inadequate. Assess which rays to fuse before you cut. Map every symptomatic joint clinically (palpate each TMT joint, perform the drawer test for instability) and on CT. Then decide ray-by-ray - because the three TMT columns behave very differently (see Background). The single most important decision is the lateral column:

Contraindications. Absolute: active infection at the surgical site (stage it - debridement and antibiotics first); and severe peripheral vascular disease (non-palpable pulses, ABI of 0.5 or lower, absent pedal perfusion on angiography). Relative: current smoking (raises non-union risk 3-4 fold, to 15-25% versus 5-15% - encourage cessation at least 6 weeks pre-operatively); poorly controlled diabetes with HbA1c above 8%; severe osteoporosis; and neuropathic (Charcot) arthropathy, which demands extended fusion, plantar plating and prolonged immobilisation. Consent specifically for non-union (5-15%), dorsiflexion malunion and transfer metatarsalgia, hardware prominence needing removal (5-10%), wound problems (higher in diabetics and smokers), deep infection (1-3%), adjacent-joint arthritis (10-20% at 5 years), and neurovascular injury including dorsalis pedis injury (2-3%). Setup. Supine on a radiolucent table with a bump under the ipsilateral buttock to externally rotate the leg for AP fluoroscopy, the knee flexed 30-45 degrees over a bolster, the C-arm brought from the contralateral side, and a well-padded thigh tourniquet inflated to 250-300mmHg. Keep tourniquet time under 90-120 minutes. Single-dose first-generation cephalosporin (e.g. cefazolin 2g IV) within 60 minutes of incision - glycopeptide where there is significant beta-lactam allergy or MRSA risk.

The goal: expose the arthritic TMT joints through dual dorsal longitudinal incisions, identify and protect the dorsalis pedis artery and deep peroneal nerve before any bone work, prepare the joint surfaces to bleeding bone with the fish-scale technique, restore tripod alignment, and stabilise with rigid compression fixation - fusing the symptomatic medial and middle columns while preserving a mobile lateral column whenever possible. The exposure is laid out in full below (and in depth on the dorsal approach to the midfoot page).

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Rehabilitation | Phase | Timing | Immobilisation / weight-bearing | Milestones and therapy | |-------|--------|--------------------------------|------------------------| | 1 | 0-2 weeks | Short-leg splint, strict NWB (crutches or knee scooter) | Elevation, multimodal analgesia, neurovascular checks; DVT prophylaxis (aspirin 325mg or enoxaparin 40mg daily for 2-3 weeks in higher-risk patients) | | 2 | 2-6 weeks | Cast or removable boot, still NWB; K-wires removed at about 6 weeks | Wound check and radiographs at 10-14 days; confirm maintained alignment | | 3 | 6-12 weeks | PWB progressing 25 to 50 to 75% if early callus; FWB by 10-12 weeks if union (bridging on 3 of 4 cortices, obliteration of the fusion line) | CT at 12 weeks if union is questionable - the gold standard for bony bridging | | 4 | 3-6 months | Stiff-soled or rocker-bottom shoe; custom orthotics in 70-80% | Physio from 12-14 weeks: ankle ROM, peroneal and tibialis-posterior strengthening, proprioception, gait re-training | Driving resumes at 10-12 weeks once FWB (right foot) and an emergency stop is safe. Return to activity: sedentary work 2-4 weeks, light duty 8-12 weeks, full/manual work 4-6 months; low-impact sport at 4-5 months, high-impact at 6-9 months, competitive sport at 6-12 months once fusion is solid. Radiographic surveillance at 4-6 months, 1 year, then yearly for 3-5 years; symptomatic hardware is removed in 5-10% at a minimum of 12 months once union is confirmed. Outcomes. Fusion 85-95% at 12-18 months with modern fixation; significant pain relief in 80-90%; AOFAS midfoot scores typically 75-85 at 2 years; return to pre-injury activity in 70-80%; satisfaction 80-90% for post-traumatic arthritis (lower, 60-70%, for primary OA and inflammatory arthropathy because of progressive disease). Complications

Pathoanatomy and epidemiology. The TMT (Lisfranc) articulation is a three-column complex. The 2nd MT base is recessed into the cuneiforms as a bony keystone, and stability rests on the ligamentous complex - the plantar Lisfranc ligament from the medial cuneiform to the 2nd MT base (3-5mm thick) is the strongest; dorsal ligaments are weak, and there is no intermetatarsal ligament between the 1st and 2nd MT, a key vulnerability in Lisfranc injury. Post-traumatic arthritis follows high-energy Lisfranc disruption in 30-50% of cases, typically declaring itself 12-24 months after injury; primary OA and inflammatory arthropathy make up the remainder, the latter often multi-ray. Functional anatomy - the basis for selective fusion. The motion data that govern the whole operation come from the cadaveric study of Ouzounian and Shereff (1989). The medial and middle columns are near-rigid; the lateral column is mobile:

Neurovascular anatomy at risk. The dorsalis pedis - the terminal anterior tibial artery - passes under the inferior extensor retinaculum, runs between EHL and EDL to the 2nd toe, and at the TMT level lies 12-15mm deep between the 1st and 2nd MT bases on the first dorsal interosseous; it gives off the first dorsal metatarsal artery then continues as the deep plantar artery through the first interspace, and is absent or diminutive in about 12% (peroneal-dominant). The deep peroneal nerve travels immediately lateral to it (motor to EDB/EHB, sensory to the first webspace). The medial plantar bundle lies 8-10mm plantar to the medial cuneiform-1st MT joint and the lateral plantar bundle plantar to the cuboid; the superficial peroneal nerve emerges 10-12cm proximal to the ankle and branches across the dorsum between the incisions. Key evidence. Two Level I RCTs establish primary arthrodesis as superior to ORIF for purely ligamentous and severe Lisfranc injuries: Ly and Coetzee (2006) reported AOFAS 88 versus 68.6 and activity 92% versus 65% of pre-injury at a mean 42.5 months, and Henning et al. (2009) showed secondary surgery fell from 78.6% (ORIF) to 16.7% (primary arthrodesis) with no functional-score difference. Series data (Komenda 1996; Sangeorzan 1990) confirm reliable pain relief with rigid fixation and grafting, and that alignment quality and timing - not age or number of joints fused - dominate outcome. Dang and Coughlin (2020) linked non-union to the number of joints spanned (3.6 vs 2.5), and Shibuya et al. (2013) identified neuropathy, longer surgery and HbA1c above 7% as independent bone-healing risk factors in diabetics. Reported union with contemporary fixation clusters around 80-95%. Guidelines, registries and global practice. TMT arthrodesis is supported by Level I evidence and consistent series data across the AO Foundation, AOFAS and BOFAS literature, with broad international consensus that primary arthrodesis is favoured for purely ligamentous and severely comminuted Lisfranc injuries and that selective (not routine) lateral-column fusion best preserves function. National registries (NJR, AJRR, AOANJRR) track arthroplasty rather than midfoot fusion, so outcome benchmarks derive from published series. Construct choice varies by region and resource: dorsal locked plating predominates in higher-resource practice, while crossed and lag-screw fixation remains effective where plating systems are less available; compression staples and intramedullary devices are emerging adjuncts. The unifying principle across settings is meticulous joint preparation, anatomic tripod alignment and rigid compression. Perioperative prophylaxis follows WHO/AAOS principles: single-dose first-generation cephalosporin within 60 minutes (glycopeptide for beta-lactam allergy or MRSA risk); mechanical thromboprophylaxis with selective chemical prophylaxis in higher-risk patients; early NSAID use remains debated on theoretical non-union grounds.