Hallux Valgus and Lesser Toe Deformities

• Hallux valgus (bunion) — lateral deviation of the great toe at the first metatarsophalangeal joint with medial deviation of the first metatarsal, producing a prominent medial eminence. Contributing factors include constrictive, narrow-toed and high-heeled footwear, a genetic predisposition, pes planus, ligamentous laxity and inflammatory arthritis.
• The bursa over the eminence becomes inflamed and painful, and transfer of load can produce metatarsalgia and lesser toe deformity.
• Hallux rigidus is the differential: pain and stiffness from osteoarthritis of the same joint, with restricted dorsiflexion rather than deviation.
• Lesser toe deformities, distinguished by which joint is flexed:
• Hammer toe — flexed proximal interphalangeal joint, extended metatarsophalangeal joint.
• Claw toe — extended metatarsophalangeal joint with both interphalangeal joints flexed; associated with neurological disease and cavus foot.
• Mallet toe — flexed distal interphalangeal joint only.
• Management is conservative first: wide toe-box footwear, padding, orthoses, and toe spacers. Surgery — osteotomy and soft-tissue realignment for hallux valgus — is for pain and function, not appearance, and recurrence is common if footwear does not change.
• In diabetes or neuropathy, these deformities create high-pressure areas and are a leading route to ulceration, so footwear assessment is preventive care.

Extrinsic (modifiable) — the shoe

• Constrictive footwear: narrow toe boxes apply a sustained lateral (valgus) force to the hallux; heels >2 inches shift load onto the forefoot and drive the toes distally into the box. This is the exposure examiners plant in the stem, and it explains the marked female predominance.
• Occupational standing/high forefoot load: prolonged weightbearing accelerates attenuation of the medial capsuloligamentous restraints.
• Obesity: increases forefoot pressure and is associated with pes planus.

Intrinsic (largely non-modifiable) — the foot

• Genetic predisposition: strong familial clustering, often autosomal dominant with variable penetrance; juvenile/adolescent hallux valgus is typically bilateral, symmetric and familial.
• Pes planus and hindfoot valgus: pronation unlocks the midfoot and destabilises the first ray during push-off.
• First ray hypermobility or metatarsus primus varus: a medially deviated first metatarsal widens the intermetatarsal angle before any deformity of the toe appears.
• Generalised ligamentous laxity: Ehlers-Danlos, Marfan, Down syndrome.
• Long or oblique first metatarsophalangeal articular surface, and a round rather than flat metatarsal head, which resists lateral subluxation poorly.

Inflammatory and neuromuscular causes

• Rheumatoid arthritis: synovitis destroys the MTP capsule and plantar plate, producing severe hallux valgus with lesser-toe dorsal dislocation and plantar metatarsal head prominence — the classic rheumatoid forefoot.
• Neurologic disease: Charcot-Marie-Tooth, cerebral palsy, post-stroke spasticity, poliomyelitis and diabetic motor neuropathy cause intrinsic-minus imbalance and produce claw toes with a cavus foot.
• Trauma: turf toe or plantar plate rupture removes a static stabiliser; mallet toe often follows distal phalanx trauma or a chronically curled toe in a short shoe.
• Diabetes mellitus with peripheral neuropathy: converts a cosmetic deformity into a limb-threatening one by adding insensate high-pressure loading; the ADA Standards of Care specify annual comprehensive foot examination including inspection for deformity.

The deforming cycle

• A medially deviated first metatarsal (metatarsus primus varus) or a laterally directed shoe force tips the proximal phalanx into valgus.
• The medial capsule attenuates while the adductor hallucis and lateral capsule contract, so the deformity becomes self-perpetuating.
• The metatarsal head slides medially off the sesamoids, which remain tethered to the second metatarsal by the deep transverse intermetatarsal ligament. On radiographs the sesamoids therefore appear laterally subluxed — in reality the metatarsal has moved.
• With the sesamoid sling displaced laterally, the abductor hallucis rotates plantarward and loses its ability to abduct, becoming a flexor and pronator; the hallux pronates so the nail faces medially.
• EHL and FHL bowstring lateral to the joint axis, converting longitudinal tendons into additional valgus deforming forces.

Why the clinical picture follows

• The uncovered medial metatarsal head plus reactive bone forms the medial eminence; the overlying adventitial bursa is chronically compressed by the shoe → bunion pain, erythema and swelling.
• The dorsomedial cutaneous branch of the superficial peroneal nerve is stretched over the eminence → numbness or a burning dysaesthesia.
• The valgus, pronated, sesamoid-deficient first ray fails to bear its share of load at push-off (loss of an effective windlass). Load transfers to the second and third metatarsal heads → transfer metatarsalgia and plantar keratoses.
• Chronic overload attenuates the second MTP plantar plate → dorsal subluxation, then the crossover toe riding over the hallux.

Hallux valgus

• Medial eminence pain worse in shoes and relieved barefoot — the cardinal complaint. Erythema, warmth and fluctuance over the eminence indicate an inflamed adventitial bursa, not infection, unless there is skin breakdown.
• Lateral deviation and pronation of the hallux, with the nail plate rotated to face medially; in advanced disease the hallux underrides or overrides the second toe.
• Transfer metatarsalgia: burning pain under the second/third metatarsal heads at push-off with plantar keratoses (calluses) — the mechanical signature of a first ray that no longer bears load.
• Dorsomedial numbness or tingling from traction on the cutaneous nerve over the eminence.
• Preserved MTP motion. Restricted, painful dorsiflexion with a palpable dorsal osteophyte and a positive grind test points instead to hallux rigidus.

Lesser toes

• Dorsal PIP callus (corn) from shoe contact in hammer toe; tip callus in mallet toe; combined dorsal IP and plantar metatarsal head callosities in claw toe.
• Flexible versus rigid is the single most important physical finding, since it determines the operation: with the ankle plantarflexed or by pushing up under the metatarsal head (push-up test), a flexible deformity corrects passively.
• Second MTP instability: pain and swelling in the second web space with a positive drawer (Lachman) test of the MTP joint indicates plantar plate attenuation and predicts crossover toe. Distinguish from Morton neuroma, which gives web-space numbness and a Mulder click.
• Cavovarus foot with clawing bilaterally should prompt a neurologic examination for Charcot-Marie-Tooth — pes cavus, hammer toes, peroneal weakness, absent reflexes.
• In neuropathy, deformity is painless; the presenting finding is a callus with underlying haemorrhage or a frank ulcer over the bony prominence.

Diagnosis is clinical; imaging grades severity and plans surgery.

Initial study — weightbearing radiographs

• Standing AP, lateral and oblique views of the foot, plus a sesamoid axial view. Non-weightbearing films systematically underestimate the deformity and are a common distractor.
• Hallux valgus angle (HVA): between the longitudinal axes of the first metatarsal and proximal phalanx; normal is roughly under 15 degrees.
• Intermetatarsal angle (IMA): between the first and second metatarsal axes; normal is roughly under 9 degrees. A wide IMA means the deformity cannot be corrected by soft tissue work alone and requires an osteotomy.
• Severity is conventionally graded mild, moderate or severe on ascending HVA and IMA thresholds, and this grading drives the choice of distal versus proximal osteotomy.
• Also assess sesamoid position relative to the metatarsal crista, joint congruency, the distal metatarsal articular angle, first tarsometatarsal obliquity/hypermobility, and first MTP joint space — loss of joint space with dorsal osteophytes indicates coexisting arthritis and shifts management toward arthrodesis rather than realignment.

Adjunctive testing

• MRI or ultrasound for suspected plantar plate tear or to distinguish it from Morton neuroma when the drawer test is equivocal.
• Inflammatory workup (RF, anti-CCP, ESR/CRP) if the forefoot deformity is bilateral, erosive and accompanied by synovitis — ACR/EULAR classification criteria are used for rheumatoid arthritis.
• Serum urate and joint aspiration if the first MTP is acutely hot and exquisitely tender: podagra is gout, not a bunion, and negatively birefringent needle-shaped crystals confirm it.
• Neurologic evaluation (including EMG/nerve conduction and consideration of CMT) for bilateral claw toes with cavovarus.
• In a diabetic patient with an ulcer over a deformity: assess perfusion (ankle-brachial index, toe pressures), perform a probe-to-bone test, obtain plain films first, and use MRI as the imaging gold standard for osteomyelitis per IDSA diabetic foot infection guidance; bone biopsy remains definitive.

• Footwear modification: a wide, deep, soft toe box, low heel, adequate length. Nothing else works if the shoe does not change, and recurrence after surgery is driven by returning to narrow shoes.
• Padding and orthoses: bunion shields, silicone toe spacers, metatarsal pads or bars to offload the lesser metatarsal heads, and a full-length insole with medial arch support for pes planus. Crest pads and toe sleeves for flexible hammer/claw toes; a rigid carbon insert (Morton extension) is used for hallux rigidus.
• Callus care: paring of keratoses, emollients, and never self-treatment with salicylic acid corn plasters in a diabetic or ischaemic foot.
• Analgesia: NSAIDs (e.g., ibuprofen) or topical NSAIDs for bursal and joint pain; acetaminophen where NSAIDs are contraindicated. There is no medical therapy that corrects the deformity — splints and spacers relieve symptoms but do not reverse the angles, a point examiners like to test.
• Intra-articular or peribursal corticosteroid injection may be used sparingly for a painfully inflamed bursa or arthritic MTP; repeated injection risks capsular attenuation and is avoided.
• Disease-directed therapy matters when inflammatory: ACR guidelines call for treat-to-target DMARD therapy (methotrexate first line) in rheumatoid forefoot disease.

Step 2 — surgery, for pain and function only

• Distal metatarsal osteotomy (chevron) with distal soft tissue realignment for mild–moderate deformity; proximal or shaft osteotomy for larger intermetatarsal angles; first tarsometatarsal arthrodesis (Lapidus) for first ray hypermobility or severe deformity; first MTP arthrodesis for severe deformity with arthritis, rheumatoid disease, or spasticity.
• Lesser toes: flexible deformity → flexor tenotomy or flexor-to-extensor transfer (Girdlestone-Taylor), with EDL lengthening/MTP capsular release; rigid deformity → PIP resection arthroplasty or arthrodesis; plantar plate repair or a Weil shortening osteotomy for metatarsalgia with MTP instability.

Contraindicated / avoid

• Surgery for cosmesis or for an asymptomatic bunion.
• Elective surgery with critical limb ischaemia, active infection, poorly controlled diabetes, or dense neuropathy — vascular assessment and glycaemic optimisation come first (ADA Standards of Care; IWGDF). In the insensate foot, protective footwear and offloading are the therapeutic goal.

Of the deformity

• Adventitial bursitis over the medial eminence: chronic shoe pressure; red, warm, fluctuant swelling. Sterile unless the skin breaks.
• Transfer metatarsalgia and intractable plantar keratoses: load shifted off the incompetent first ray; painful callus under the second/third metatarsal heads.
• Second MTP plantar plate rupture → crossover toe: progressive dorsomedial drift of the second toe, positive drawer test; once dislocated it is no longer passively correctable.
• Dorsomedial cutaneous nerve irritation: numbness or burning along the medial hallux.
• Nail and skin problems: ingrown nail from hallux pronation, corns over the dorsal PIP, subungual ulceration in mallet toe.
• Neuropathic ulceration — the emergency pathway. In diabetes the deformity creates a focal high-pressure insensate area; a callus with underlying haematoma precedes frank ulceration. Escalation to cellulitis, deep abscess, osteomyelitis, wet gangrene or sepsis is limb- and life-threatening and needs urgent surgical assessment, cultures and empiric antibiotics per IDSA/IWGDF diabetic foot infection guidance. Probe-to-bone positivity substantially raises the likelihood of osteomyelitis. A hot, swollen, erythematous but non-tender neuropathic foot with normal inflammatory markers should also raise Charcot neuroarthropathy — an urgent immobilisation issue, not a bunion.

Of treatment

• Recurrence: the commonest surgical complication, especially with undercorrected intermetatarsal angle, first ray hypermobility, or return to narrow shoes.
• Hallux varus (overcorrection): excessive lateral release with medial capsular plication, classically after aggressive McBride-type procedures with fibular sesamoid excision; the toe deviates medially and catches in the shoe.
• Avascular necrosis of the metatarsal head after distal osteotomy combined with extensive lateral soft tissue release — progressive pain, joint collapse, sclerosis on film.
• Nonunion, malunion, dorsiflexion malunion or excessive first ray shortening, each producing a new transfer lesion under the lesser metatarsals.
• Post-arthrodesis stiffness and IP joint arthritis from compensatory motion.
• Floating toe, recurrent deformity or vascular compromise after lesser toe correction; surgical site infection, wound dehiscence, venous thromboembolism, and complex regional pain syndrome.

• Sort lesser toe deformities by the flexed joint. Hammer = PIP flexed; mallet = DIP flexed; claw = MTP extended with both IP joints flexed. Claw toes bilaterally with a cavus foot means look for neurologic disease — Charcot-Marie-Tooth is the association examiners test.
• Hallux valgus versus hallux rigidus. Deviation with preserved motion = hallux valgus. Painful, limited dorsiflexion with a dorsal osteophyte and a positive grind test = hallux rigidus (osteoarthritis). An acutely hot, exquisitely tender first MTP is podagra — aspirate for negatively birefringent needle-shaped crystals.
• The sesamoids do not move; the metatarsal does. They stay tethered to the second metatarsal by the deep transverse intermetatarsal ligament, which is why they look laterally subluxed on the radiograph.
• Order weightbearing radiographs. Non-weightbearing films understate the hallux valgus and intermetatarsal angles — a favourite distractor.
• Best next step for a painful bunion is almost always a wide toe-box shoe plus padding/orthoses, not surgery. Surgery is for pain and function, never appearance, and recurrence is high if footwear does not change.
• Assess flexible versus rigid before choosing an operation: flexible → tendon transfer/tenotomy (Girdlestone-Taylor); rigid → PIP resection arthroplasty or arthrodesis.
• Overcorrection produces hallux varus, classically after an aggressive lateral release with fibular sesamoidectomy.
• In diabetes, the deformity is the ulcer risk. ADA Standards of Care mandate an annual comprehensive foot exam with 10-g monofilament testing; therapeutic footwear and offloading are preventive care, and an insensate ulcer that probes to bone should prompt evaluation for osteomyelitis under IDSA guidance.
• Second web space pain with a positive MTP drawer test is plantar plate insufficiency (pre-crossover toe) — not Morton neuroma, which gives web-space numbness and a Mulder click.