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Foot & Ankle

Lesser Toe Deformity Correction

Hammer, claw, and mallet toe correction (PIPJ fusion, flexor-to-extensor transfer) for FRCS/FRACS exam preparation

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Dorsal PIPJ incision, K-wire fixation | Plantar incision for flexor-to-extensor transfer | basic

Surgical Imaging

Imaging Gallery

Three-panel showing clinical claw toes AP foot X-ray with dislocated MTP joints and 3D CT reconstruction
Advanced lesser toe deformities in rheumatoid arthritis: three-panel composite. Panel A: clinical photograph showing severe forefoot deformity with marked claw toe deformities of the lesser toes (curling under the metatarsal heads) and hallux valgus — demonstrating the typical rheumatoid forefoot that requires surgical correction. Panel B: AP weight-bearing foot radiograph showing subluxation and dislocation of multiple metatarsophalangeal joints with metatarsal head exposure and erosive changes at the MTP joints. Panel C: three-dimensional CT reconstruction of the foot demonstrating the spatial relationship of the displaced metatarsal heads and phalanges, illustrating the complex three-dimensional nature of the deformity requiring PIPj arthrodesis or Girdlestone-Taylor transfer correction.Credit: Open-i NIH (PMC4028534) (CC BY PMC Open Access)

Critical Danger Structures

Danger 1: Digital Neurovascular Bundle

Plantar digital neurovascular bundles. Location: Run along medial and lateral plantar aspects of each toe, immediately beneath plantar skin and subcutaneous fat. At particular risk during plantar incision for Girdlestone-Taylor transfer and during K-wire insertion. Protection: Stay strictly midline in the plantar incision, use blunt dissection to the flexor sheath, and confirm K-wire trajectory before drilling. Injury causes permanent toe ischaemia or painful digital neuroma.

Danger 2: Avascular Necrosis of Proximal Phalanx Head

Blood supply to proximal phalanx head. Location: End-arteries enter via the periosteum and collateral ligament origins at the PIPJ. Protection: Minimise periosteal stripping; resect only the distal articular surface of the proximal phalanx rather than over-aggressive bone removal. Excessive resection devascularises the residual bone stock, leading to AVN, non-union, and toe shortening with floppy digit.

Danger 3: Overcorrection (Extension Contracture)

MTP hyperextension / extension contracture. Location: MTP joint and extensor mechanism. Occurs when the extensor tenotomy is combined with a tight dorsal MTP capsulotomy leaving an unchecked extensor force, or when the Girdlestone-Taylor transfer is placed under excessive tension. Result is a "floating toe" that cannot contact the ground, causing transfer lesions under adjacent metatarsal heads. Protect by setting transfer tension with MTP at 20° plantarflexion.

Danger 4: Pin-Track Infection (K-wire)

Percutaneous K-wire pin-track. Location: Where the K-wire exits the tip of the toe. Risk increases after 4 weeks. Protection: Cut wire flush with skin (buried) or 2-3mm proud for easy retrieval, dress daily, advise patient to keep dry. Remove at 4-6 weeks without exception. Established pin-track infection requires urgent K-wire removal, wound swab, and antibiotics; delay risks osteomyelitis and cortical bone destruction.

Danger 5: Recurrence

Deformity recurrence. Location: At the PIPJ, DIPJ, or MTP joint depending on initial procedure. Rate: Up to 30% at 5 years. Causes: Inadequate MTP release, failure to address flexor hallucis or intrinsic tightness, progressive underlying neurological disease, inappropriate choice of soft-tissue procedure for a rigid deformity. Prevention requires flexible-vs-rigid assessment, complete MTP capsular release where indicated, and patient counselling about disease progression.

Mnemonic

HCMHCM Classification - Three Deformity Types

Mnemonic

FRAPFRAP Protocol - Surgical Decision Ladder

Primary Indications

Absolute Indications

  • Rigid lesser toe deformity causing painful corns, callosities, or ulceration refractory to conservative measures
  • Failed minimum 3 months of conservative treatment (toe-box modification, silicone splints, padding, physiotherapy)
  • Rigid PIPJ flexion deformity (hammer or claw toe) causing painful dorsal prominence or interphalangeal joint corn
  • Rigid DIPJ flexion deformity (mallet toe) causing distal tip corn or nail deformity refractory to conservative care

Relative Indications

  • Flexible deformity causing functional impairment or shoewear difficulties where splinting has failed
  • Flexible claw toe with plantar MTP synovitis or MTP instability (positive drawer test)
  • Lesser toe deformity in the context of hallux valgus requiring correction (adjacent toe deformity resolves with hallux correction in ~30%, assess pre-operatively)
  • Ulceration or skin breakdown in the neuropathic foot where deformity is the underlying cause

Contraindications

  • Active infection in the operative field or toe ischaemia
  • Severe peripheral arterial disease (ABI <0.5 or absent toe pressures) — vascular workup and reconstruction first
  • Unrealistic patient expectations (toe will remain straight but may not look normal)
  • Inadequate trial of conservative management (<3 months for flexible deformity)
  • Underlying progressive neurological disease not yet managed — address the cause first

Deformity Classification

Hammer Toe

  • Definition: Flexion deformity at the PIPJ with the MTP joint neutral or minimally extended and the DIPJ in neutral or mild flexion
  • Aetiology: Intrinsic-extrinsic imbalance; often associated with hallux valgus, tight footwear
  • Flexible stage: PIPJ corrects passively; treat with flexor tenotomy or transfer
  • Rigid stage: Fixed PIPJ flexion; requires PIPJ arthrodesis with resection of proximal phalanx condyles

Claw Toe

  • Definition: Hyperextension at the MTP joint combined with flexion at both PIPJ and DIPJ (intrinsic minus posture)
  • Aetiology: Intrinsic muscle failure — cavus foot, Charcot-Marie-Tooth, rheumatoid arthritis, stroke, idiopathic
  • Key point: The MTP hyperextension is the primary deformity; the interphalangeal flexion is secondary
  • Flexible stage: Kelikian push-up test positive; Girdlestone-Taylor transfer of FDL ± MTP capsular release
  • Rigid stage: PIPJ arthrodesis + MTP dorsal capsulotomy + extensor lengthening

Mallet Toe

  • Definition: Flexion deformity isolated to the DIPJ; PIPJ and MTP normal
  • Aetiology: FDL overactivity, chronic trauma, capsular contracture
  • Flexible stage: FDL tenotomy
  • Rigid stage: DIPJ arthrodesis with condylectomy and K-wire fixation

Evidence Base

The evidence below is summarised from primary papers verified against PubMed. Key practical message for the exam: PIPJ arthrodesis is the standard for the rigid hammer/claw toe; the Girdlestone-Taylor flexor-to-extensor transfer is the standard dynamic procedure for the flexible claw toe; and percutaneous K-wire fixation remains comparable to far more expensive intramedullary implants for PIPJ fusion. Reported osseous union rates for K-wire PIPJ arthrodesis cluster around 70-75% radiographically (clinically stable fibrous union is often asymptomatic), so do not overstate fusion as exceeding 90 percent.

The treatment of claw toes by multiple transfers of flexor into extensor tendons

IV
Taylor RG • J Bone Joint Surg Br
Clinical Implication: The landmark reference for the flexible claw toe operation — cite by name and year when describing the technique in a viva.
Verify on PubMed (PMID 14880572)

The pathological anatomy of claw and hammer toes

IV
Myerson MS, Shereff MJ • J Bone Joint Surg Am
Clinical Implication: Justifies routine collateral ligament and capsular release at the PIPJ (and MTP where hyperextended) rather than relying on bone resection alone.
Verify on PubMed (PMID 2913002)

Crossover second toe deformity

IV
Coughlin MJ • Foot Ankle
Clinical Implication: Reinforces that lesser toe deformity with MTP instability needs the MTP joint addressed (plantar plate / capsule) or the IP correction will recur.
Verify on PubMed (PMID 3623359)

Transfer of the flexor digitorum longus for the correction of lesser-toe deformities

IV
Boyer ML, DeOrio JK • Foot Ankle Int
Clinical Implication: Modern outcome evidence that a correctly tensioned flexor-to-extensor transfer gives high satisfaction and avoids the floating toe — set MTP tension neutral to slight plantarflexion, not extension.
Verify on PubMed (PMID 17475135)

Radiographic analysis of PIPJ arthrodesis with an intramedullary fusion device for lesser toe deformities

IV
Ellington JK, Anderson RB, Davis WH, Cohen BE, Jones CP • Foot Ankle Int
Clinical Implication: Bony union after PIPJ arthrodesis is frequently incomplete; a stable fibrous union that maintains alignment is an acceptable, usually asymptomatic outcome — temper expectations of true bony fusion.
Verify on PubMed (PMID 20460062)

SmartToe, ToeGrip and buried k-wire versus percutaneous k-wire fixation for 2nd PIPJ arthrodesis: a comprehensive review of outcomes

III
Hendrick SE, Kannegieter E • Foot (Edinb)
Clinical Implication: Percutaneous K-wire remains a reliable, far cheaper standard for PIPJ arthrodesis; intramedullary implants offer modestly higher radiographic union but at greatly increased cost — the preferred answer in a resource-conscious global exam setting.
Verify on PubMed (PMID 33181397)

Clinical Decision Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A 55-year-old woman presents with painful second-toe deformity. She has a dorsal corn over the PIPJ and tip pain from a distal corn at the third toe. On examination: the second toe has a PIPJ flexion deformity that partially corrects with the Kelikian push-up test; the third toe PIPJ deformity does not correct with the push-up test. How do you classify these deformities and what surgical procedures would you plan?"

PRACTICAL APPROACH
These are both hammer toe deformities — isolated PIPJ flexion with neutral MTP joints — but critically they are at different stages. The second toe has a flexible hammer toe: the Kelikian push-up test (applying axial compression under the metatarsal head to recreate normal ground reaction force) causes partial correction of the PIPJ flexion, indicating the deformity is not yet fixed. The third toe has a rigid hammer toe: the PIPJ does not correct passively, indicating fixed capsular and soft tissue contracture. For the second toe I would plan a flexor tenotomy (FDB at the PIPJ level) or, if the MTP joint is also unstable, consider a Girdlestone-Taylor flexor-to-extensor transfer of FDL to provide dynamic MTP stabilisation and PIPJ correction. For the third toe the rigid PIPJ requires a PIPJ arthrodesis: dorsal elliptical skin excision, extensor tenotomy, collateral ligament release, resection of the proximal phalanx head with decortication of the middle phalanx base (3-4 mm per side), and K-wire fixation antegrade. I would also formally assess whether these deformities are occurring in isolation or in the context of hallux valgus, cavus foot, or inflammatory arthropathy. A hallux valgus pushing the second toe into adduction and elevation is a common underlying cause; if present, I would plan correction of the hallux valgus at the same sitting since approximately 30% of lesser toe deformities associated with hallux valgus resolve after hallux correction alone. Post-operatively the K-wire is retained for 4-6 weeks in a stiff-soled shoe; removal at 6 weeks under local anaesthesia, followed by buddy strapping and wide-toe-box footwear for a further 6 weeks.
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"Explain the difference between a hammer toe, a claw toe, and a mallet toe. Which operation would you perform for a flexible claw toe of the second toe, and walk me through the technique?"

PRACTICAL APPROACH
Hammer toe is a flexion deformity at the PIPJ alone; the MTP joint is in neutral or mild extension and the DIPJ is variable. Mallet toe is a flexion deformity isolated to the DIPJ, with the PIPJ and MTP joint in normal alignment. Claw toe involves all three joints: MTP hyperextension combined with PIPJ and DIPJ flexion — the classic intrinsic minus posture. The distinction matters because claw toe reflects intrinsic muscle failure, and the primary deformity is the MTP hyperextension rather than the PIPJ flexion; this changes the surgical approach. For a flexible claw toe — where the Kelikian push-up test restores normal toe alignment — I would perform a Girdlestone-Taylor flexor-to-extensor tendon transfer as described by Taylor in 1951. Technique: the patient is supine, tourniquet applied, under ankle block or general anaesthesia. I make a plantar longitudinal incision over the proximal phalanx, strictly in the midline to protect the medial and lateral digital neurovascular bundles running along the plantar-lateral borders of the toe. I incise the A2 flexor sheath, identify FDL deep to FDB at Camper's chiasm, and split FDL longitudinally into two equal slips, leaving both slips attached distally to the DIPJ insertion. Using a curved clamp I tunnel each slip subcutaneously around the medial and lateral borders of the proximal phalanx from plantar to dorsal, emerging at the level of the extensor expansion. I then position the MTP joint at 10-20° of plantarflexion and suture each slip to the lateral bands of the extensor expansion with 2-0 non-absorbable sutures under appropriate tension, confirming the toe lies flat with no residual resting PIPJ or DIPJ flexion. If there is a fixed MTP hyperextension component, I perform a concomitant dorsal MTP extensor tenotomy and capsulotomy through a separate dorsal incision before completing the transfer. Post-operatively: stiff-soled shoe weight-bearing, sutures out at 12-14 days, physiotherapy from 6 weeks.
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"Three months after PIPJ arthrodesis of the second toe, your patient returns with a pin-track infection. The K-wire was never removed. What is your management, and what complications concern you?"

PRACTICAL APPROACH
This is a preventable complication — K-wire removal should have occurred at 4-6 weeks post-operatively. At three months, the wire has been retained well beyond the recommended period, and a pin-track infection at this stage must be treated as a potentially deep infection until proven otherwise. My immediate management would be: (1) Clinical assessment — examine for systemic signs of infection (pyrexia, tachycardia), assess extent of local infection (erythema, swelling, discharge, whether the infection tracks beyond the pin site), and check the neurovascular status of the toe. (2) Imaging — X-ray the toe to assess K-wire position, check for cortical bone erosion around the wire (periosteal reaction, osteolysis) which would indicate established osteomyelitis, and confirm whether the arthrodesis site has united. (3) Remove the K-wire — urgent removal under local anaesthesia in clinic or in theatre; this is the single most important step; retained hardware in an infected field perpetuates infection. (4) Wound swab for microbiology (aerobic and anaerobic); FBC, CRP, ESR baseline. (5) Empirical antibiotics: oral cephalexin (or flucloxacillin) covering Staphylococcus aureus pending culture result; escalate to IV antibiotics (flucloxacillin or vancomycin) if systemic signs present or osteomyelitis confirmed. The main complications I am concerned about are: osteomyelitis of the proximal and middle phalanges requiring prolonged antibiotics (4-6 weeks IV) and possibly surgical debridement or digital amputation if bone destruction is severe; non-union of the PIPJ arthrodesis if the wire was providing fixation before bony union was achieved; and persistent sinus or deep space infection. After resolution of infection I would review the X-ray for bony union. If non-union persists, revision arthrodesis can be considered once all infection has been eradicated.

Lesser Toe Deformity Correction — Exam Summary

Clinical summary

References

  1. Taylor RG. The treatment of claw toes by multiple transfers of flexor into extensor tendons. J Bone Joint Surg Br. 1951;33-B(4):539-542. PMID: 14880572. DOI: 10.1302/0301-620X.33B4.539. Original description of the Girdlestone-Taylor flexor-to-extensor transfer technique for flexible claw toe correction.

  2. Myerson MS, Shereff MJ. The pathological anatomy of claw and hammer toes. J Bone Joint Surg Am. 1989;71(1):45-49. PMID: 2913002. Cadaveric sequential-sectioning study showing that adequate correction often requires more extensive soft-tissue release than previously believed.

  3. Coughlin MJ. Crossover second toe deformity. Foot Ankle. 1987;8(1):29-39. PMID: 3623359. DOI: 10.1177/107110078700800108. Clinical series defining crossover second toe as failure of the lateral MTP collateral ligament and plantar plate, with ~90% satisfaction after correction.

  4. Boyer ML, DeOrio JK. Transfer of the flexor digitorum longus for the correction of lesser-toe deformities. Foot Ankle Int. 2007;28(4):422-430. PMID: 17475135. DOI: 10.3113/FAI.2007.0422. Series of 38 patients (79 toes) reporting 89% satisfaction and no floating toes with a correctly tensioned flexor-to-extensor transfer.

  5. Ellington JK, Anderson RB, Davis WH, Cohen BE, Jones CP. Radiographic analysis of proximal interphalangeal joint arthrodesis with an intramedullary fusion device for lesser toe deformities. Foot Ankle Int. 2010;31(5):372-376. PMID: 20460062. DOI: 10.3113/FAI.2010.0372. StayFuse intramedullary device for PIPJ fusion: 60.5% radiographic union but maintained alignment in most.

  6. Hendrick SE, Kannegieter E. SmartToe, ToeGrip and buried k-wire versus percutaneous k-wire fixation for 2nd PIPJ arthrodesis: a comprehensive review of outcomes. Foot (Edinb). 2020;45:101692. PMID: 33181397. DOI: 10.1016/j.foot.2020.101692. Pooled review of 3878 outcomes: K-wire union ~73% vs SmartToe 87.2%, with implants costing 640-894 times more and no clear patient-reported advantage.

  7. Schrier JC, Verheyen CC, Louwerens JW. Definitions of hammer toe and claw toe: an evaluation of the literature. J Am Podiatr Med Assoc. 2009;99(3):194-197. PMID: 19448169. DOI: 10.7547/0980194. Literature review proposing that MTP extension is the discriminating feature of claw toe and PIPJ flexion the single criterion for hammer toe.

  8. Coughlin MJ, Mann RA, Saltzman CL, eds. Lesser toe deformities. In: Mann's Surgery of the Foot and Ankle. 9th ed. Philadelphia: Mosby Elsevier; 2014. Definitive textbook chapter on the modern classification, operative technique, and outcomes for all lesser toe deformities (textbook reference, no PMID).