High-yield overview

Dorsal midline or medial approach to first metatarsophalangeal joint | intermediate

Surgical Imaging

Imaging Gallery

Three-panel first MTP joint arthrodesis showing open joint A plate fixation B and post-op foot X-ray C — First metatarsophalangeal joint arthrodesis technique: three-panel series demonstrating the key operative steps. Panel A: dorsal exposure with the first MTP joint fully opened, showing the prepared articular surfaces after cartilage removal and contouring. Panel B: a low-profile dorsal plate with locking screws applied across the arthrodesis site, with the hallux positioned in the correct alignment (10–15° valgus, 10–15° dorsiflexion). Panel C: post-operative AP foot radiograph confirming plate and screw positioning with satisfactory joint position for fusion.Credit: Open-i NIH (PMC4074606) (CC BY PMC Open Access)

Three-panel intraoperative series showing wound closure and joint preparation for first MTPJ arthrodesis — First MTPJ arthrodesis — intraoperative technique detail: three-panel series. Panel A: dorsal wound after skin closure with interrupted sutures, demonstrating the longitudinal incision centered over the first MTP joint. Panel B: close-up intraoperative view during arthrodesis preparation, showing retracted soft tissues and clamp manipulation of the joint. Panel C: wide-field intraoperative view of the opened first MTP joint showing the metatarsal head and proximal phalanx base after cartilage removal, with the joint surfaces prepared for plate fixation.Credit: Open-i NIH (PMC4074606) (CC BY PMC Open Access)

Critical Danger Structures and Position Errors

Danger 1: Medial Digital Nerve

Medial plantar digital nerve to hallux. Location: Runs along medial plantar surface of proximal phalanx, vulnerable during medial periosteal dissection and during cup-and-cone reaming of the phalanx base. Protection: Stay dorsal to midaxial line during periosteal stripping, use retractors with care on plantar medial corner. Injury causes permanent numbness medial hallux and painful neuroma.

Danger 2: Malposition — Dorsiflexion

Position error: insufficient dorsiflexion (toe flat to floor). Target is 15 to 20 degrees dorsiflexion relative to the first metatarsal shaft. Too little dorsiflexion means the hallux lies flat and loads the interphalangeal joint during push-off, causing IPJ osteoarthritis. Too much dorsiflexion causes dorsal skin pressure in footwear. Check intraoperatively with the foot flat: hallux tip should just clear the floor.

Danger 3: Malposition — Valgus

Position error: insufficient or excessive valgus. Target is 5 to 10 degrees valgus. Too little valgus (varus) causes the hallux to abut the second toe during gait, producing painful impingement. Too much valgus causes overlapping second toe and cosmetic deformity. Neutral rotation is mandatory — pronation or supination is poorly tolerated and is a common cause of revision.

Danger 4: Shortening

Excessive bone resection causing hallux shortening. Remove cartilage and subchondral sclerosis only — do not sacrifice cortical bone unnecessarily. Shortening alters the weight-bearing platform, transfers load to lesser metatarsals, and causes cosmetic deformity. In Keller's salvage, structural bone graft is mandatory to restore length. Check length against second toe before fixation.

Danger 5: IPJ Arthritis from Over-dorsiflexion

Interphalangeal joint overload. If the fusion is positioned in excessive dorsiflexion (beyond 20 degrees), the ground reaction force during late stance transfers entirely to the IPJ, causing accelerated IPJ degeneration. This is the direct mechanical consequence of malposition and one of the most common late complications requiring revision. Confirm position prior to final tightening.

Mnemonic

FUSEFUSE — Critical Steps for First MTPJ Arthrodesis

Mnemonic

GRADEGRADE — Coughlin and Shurnas Classification

Primary Indications

Absolute Indications

Grade IV hallux rigidus (Coughlin and Shurnas classification): bone-on-bone with rigid, globally painful first MTPJ
Failed cheilectomy for advanced hallux rigidus with persistent or worsening symptoms
Rheumatoid arthritis forefoot with first MTPJ destruction (often combined with lesser MTPJ procedures)
Salvage of failed Keller's resection arthroplasty or resection arthroplasty (requires bone graft to restore length)

Relative Indications

Grade III hallux rigidus in heavy-demand patients where cheilectomy alone unlikely to maintain function
Hallux valgus with coexisting first MTPJ osteoarthritis where correction and arthrodesis provide combined solution
Neuromuscular hallux valgus with MTPJ degeneration (e.g., cerebral palsy, poliomyelitis) where softtissue correction alone insufficient
First ray hypermobility with symptomatic MTPJ osteoarthritis
Septic arthritis with irreversible joint destruction after infection clearance

Contraindications

Active infection at operative site (relative: treat infection first, delayed arthrodesis acceptable)
Severe peripheral vascular disease precluding healing (absolute)
Avascular necrosis of the first metatarsal head without revascularisation potential (relative)
Patient with IPJ arthritis who understands accelerated IPJ loading after fusion (discuss; not absolute contraindication but requires counselling)
Unrealistic patient expectations about footwear limitations post-fusion

Coughlin and Shurnas Classification (2003)

Grade 0: No pain, full dorsiflexion ROM greater than 60 degrees, no radiographic changes.

Grade I: Mild dorsal aching, mild restriction of motion (40 to 60 degrees), dorsal osteophyte only, no joint space narrowing.

Grade II: Moderate pain, moderate restriction of motion (30 to 40 degrees), dorsal and lateral osteophytes, less than 25% joint space loss.

Grade III: Severe pain and stiffness, motion markedly restricted (10 to 30 degrees), extensive osteophytosis with dorsal, lateral, and medial involvement, more than 25% joint space loss, subchondral cysts and sclerosis. IPJ may have limited motion. Sesamoids may be involved.

Grade IV: All Grade III features plus complete loss of joint space (bone-on-bone) on radiograph; rigid MTPJ; may have loose bodies, sesamoid destruction.

Surgical Implication: Grades I and II — cheilectomy (removes the dorsal 25 to 30% of the metatarsal head, restoring the plantarflexion arc). Grade III — cheilectomy with possible Moberg phalanx osteotomy or interpositional arthroplasty if more than half the metatarsal head cartilage remains; if under 50% cartilage remains, treat as for Grade IV. Grade IV — first MTPJ arthrodesis is the reference standard. The original Coughlin and Shurnas rule was that arthrodesis is indicated for Grade IV, or for Grade III with under 50% of the metatarsal head cartilage remaining at surgery.

Clinical Decision Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"You are performing a first MTPJ arthrodesis for Grade IV hallux rigidus using cup-and-cone reaming. After provisional K-wire fixation you place the foot flat on the table. The hallux tip is pressing firmly against the table surface. What does this mean and what do you do?"

PRACTICAL APPROACH

This indicates the fusion position is in insufficient dorsiflexion — the hallux is too flat relative to the floor. For the foot-flat ground clearance test, the hallux tip should just clear the floor (approximately 1 to 2 mm elevation), not contact it. The fusion position is currently in less than the target 15 to 20 degrees of dorsiflexion relative to the first metatarsal shaft. The consequence of leaving the toe in this position is that during the push-off phase of gait, all dorsiflexion demand is transferred to the interphalangeal joint. The IPJ bears a ground reaction force for which it is not designed, leading to accelerated IPJ osteoarthritis — one of the most common late complications of malpositioned first MTPJ arthrodesis. My immediate action: remove the K-wires, adjust the position by increasing dorsiflexion at the fusion interface, and re-provisionally fix with K-wires. If using cup-and-cone reamers the spherical surfaces allow this adjustment without additional bone loss. I re-check the floor clearance test, and also confirm the valgus is 5 to 10 degrees and rotation is neutral before proceeding to definitive plate and screw fixation. I confirm final position with fluoroscopy in both AP and lateral projections before final screw tightening. I would also counsel the patient pre-operatively that post-fusion the IPJ is likely to develop some stiffness and degenerative change over time regardless, and that footwear modification with a rocker-bottom sole reduces IPJ loading after fusion.

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A 58-year-old woman had a Keller's resection arthroplasty for hallux rigidus at another institution 12 years ago. She now presents with severe pain, instability, and a floppy hallux. She cannot push off from the ground. Her radiographs show the classic 'floppy toe' deformity with proximal phalanx resection. How do you approach the surgical management?"

PRACTICAL APPROACH

This is a failed Keller's resection arthroplasty — a relatively common long-term failure mode of resection arthroplasty. Loss of the proximal phalanx base removes the static stabilisers of the MTPJ and creates a biomechanically deficient first ray. The clinical findings of floppy toe, instability, inability to push off, and pain are classic and indicate surgical reconstruction is warranted. The procedure is a salvage arthrodesis, which is more complex than primary arthrodesis. Key differences: there will be a length deficit from the original resection that must be addressed, there will be soft-tissue scarring and potentially absent or attenuated plantar plate, and bone stock may be compromised. My surgical approach: I would plan a dorsal incision as for standard first MTPJ arthrodesis. On exposure, I assess the length deficit — typically 8 to 15 mm. I prepare the metatarsal head and the remaining proximal phalanx stump. A structural bone graft is required to bridge the defect and restore length; iliac crest autograft is gold standard here — a tricortical or corticocancellous block shaped to the defect. Allograft is an alternative but with higher non-union risk. I fix with a dorsal locking plate, which must span the graft-host interfaces at both ends. Crossed screws are generally insufficient across a graft-host interface in this setting. Fixation must be rigid given the compromised bone stock. Position must still achieve the same targets: 15 to 20 degrees dorsiflexion, 5 to 10 degrees valgus, neutral rotation. Outcomes: union rate approximately 85 to 90% in specialist series with bone grafting. Patients should be counselled that this is a complex salvage procedure with higher complication rates than primary arthrodesis, and they should expect a period of non-weight-bearing followed by protective weight-bearing in a stiff-soled shoe.

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A colleague presents you with a 47-year-old male with painful stiff first MTPJ. He has 20 degrees of dorsiflexion, bone-on-bone on radiograph, global pain, sesamoid involvement, and has failed conservative treatment including NSAIDs and orthotic insoles for 18 months. Your colleague says he would like to perform a cheilectomy. Do you agree? What would you recommend?"

PRACTICAL APPROACH

I would not agree with primary cheilectomy in this case. The clinical and radiographic findings describe Grade IV hallux rigidus by the Coughlin and Shurnas classification: bone-on-bone on radiograph, marked restriction of motion at 20 degrees, global pain including at rest and throughout the arc of motion, sesamoid involvement, and failure of conservative management. Grade IV is the threshold at which arthrodesis — not cheilectomy — is indicated as the gold standard. Cheilectomy is a debridement procedure that removes the dorsal 25 to 30% of the metatarsal head and the dorsal osteophytes. It is appropriate for Grades I and II where significant articular cartilage is preserved and pain is predominantly dorsal impingement pain (pain only at terminal dorsiflexion, not through the full arc). Some surgeons extend it to selected Grade III cases. However, in Grade IV with bone-on-bone arthritis and global pain including at rest and through the full arc of motion, cheilectomy does not address the underlying articular pathology and is unreliable in this grade — Coughlin and Shurnas' 2003 landmark study found cheilectomy predictable only for Grades I, II and selected Grade III, and recommended arthrodesis for Grade IV or for Grade III with under 50% of the metatarsal head cartilage remaining. My recommendation is first MTPJ arthrodesis. I would explain to this patient that fusion reliably relieves pain by eliminating the arthritic joint, has the strongest evidence base of any procedure for hallux rigidus (the only operation rated Grade B in the McNeil and Baumhauer evidence review, and superior to total toe replacement in the Gibson RCT), and allows return to normal footwear and most activity. He must be counselled that the joint will be permanently stiff — this is the mechanism of pain relief — and that footwear with a rocker-bottom sole or stiff toe-box is recommended post-fusion. He should also understand the IPJ will bear increased load and that IPJ stiffness may develop long-term. I would also advise against total toe replacement in this age group — evidence shows arthrodesis is superior in long-term satisfaction and revision rate.