Hammertoe

Hammertoe is a fixed or flexible deformity of a lesser toe with flexion at the proximal interphalangeal joint, and the metatarsophalangeal and distal interphalangeal joints held neutral or in slight extension. The second toe is affected most often.

• Flexible deformity corrects with passive pressure. Rigid (fixed) deformity does not, because of capsular and tendon contracture and eventual joint stiffness.
• Causes: tight or short shoes, a second toe longer than the great toe, hallux valgus, muscle imbalance between intrinsic and extrinsic muscles, flat or high arched feet, rheumatoid arthritis, neuromuscular disease, trauma and diabetes. It becomes more common with age and is much more frequent in women.
• A rubbing dorsal corn over the proximal interphalangeal joint and a distal corn at the toe tip are common, and in neuropathic feet these precede ulceration.

• A toe that is bent upward at the middle joint, with pain, a dorsal corn or callus, redness and soreness in shoes, and pain under the metatarsal head (metatarsalgia) because the fat pad is displaced.
• Examination: test flexibility by pushing the proximal phalanx down and the toe up (flexible if it corrects), check for metatarsophalangeal subluxation or instability (crossover deformity, drawer test), nail changes, toe tip ulcers, and sensation and pulses.
• Differential diagnosis: claw toe (metatarsophalangeal hyperextension with flexion at both interphalangeal joints), mallet toe (distal interphalangeal flexion), plantar plate tear, rheumatoid deformity, gout and Charcot-Marie-Tooth disease.
• Red flags: ulceration, infection, an acutely red hot toe, diabetic neuropathy, absent pulses and sudden onset without trauma.
• Complications: corns, ulcers, bursitis, infection, osteomyelitis of the toe in diabetes, difficulty with footwear and metatarsalgia.

• Clinical. Examine the foot standing and seated, assess flexibility, the other toes, alignment of the great toe, calf tightness, perfusion and neuropathy.
• Weight bearing X-rays (anteroposterior, oblique, lateral) show joint alignment, arthritis, subluxation and bony prominences.
• Ultrasound or MRI for suspected plantar plate tear. Blood tests (HbA1c, CRP, rheumatoid markers) when systemic disease is suspected. Probe any ulcer to bone and image for osteomyelitis.

• Conservative treatment for flexible deformity and as first line:
  • Wide, deep toe box shoes with a low heel, and avoidance of tight, pointed shoes.
  • Soft toe sleeves, gel caps, toe crest pads (under the toes to hold them flat) and metatarsal pads to offload the heads.
  • Toe stretching and strengthening: towel curls, marble pick ups, manual stretching of the toe into extension (10 repetitions, 3 times daily), and calf stretching.
  • Taping the toe into a corrected position.
  • Treat corns by paring every 4 to 8 weeks. Do not use acid corn plasters in diabetes or poor circulation.
  • Paracetamol 1 g orally 6 hourly, short course ibuprofen 400 mg 8 hourly with food, or topical diclofenac 1% gel for pain.
• Surgery for pain, ulceration or footwear problems after 3 to 6 months of failed conservative care:
  • Flexible deformity: flexor digitorum longus tendon transfer to the dorsum of the proximal phalanx (flexor to extensor transfer).
  • Rigid deformity: proximal interphalangeal joint resection arthroplasty (removal of the head of the proximal phalanx) or fusion with a wire, screw or implant, often with a temporary pin for 4 to 6 weeks.
  • Metatarsophalangeal involvement: plantar plate repair, extensor lengthening, capsular release, or a shortening osteotomy of the metatarsal (Weil type).
  • Local or regional anaesthesia is used, with cefazolin 2 g IV prophylaxis.
  • Recovery: stiff soled shoe for 4 to 6 weeks, and about 80 to 90% have good results, with recurrence, stiffness, swelling and a floating toe as complications.
• Infected corn or ulcer: debride and treat with flucloxacillin 500 mg orally 6 hourly for 5 to 7 days (clindamycin 300 to 450 mg 8 hourly in penicillin allergy), and in diabetes escalate to wider cover with urgent foot clinic review.
• Special groups:
  • Diabetes and neuropathy: daily foot checks, therapeutic footwear, podiatry every 4 to 8 weeks, and early treatment of any skin breakdown.
  • Rheumatoid arthritis: control the disease, with custom footwear, and surgery by foot specialists.
  • Pregnancy: supportive shoes, padding and paracetamol. Avoid NSAIDs after 20 weeks.
  • Children: uncommon, so look for a neurological cause.
• Follow up: review in 6 to 8 weeks. Refer to podiatry or foot and ankle surgery for rigid deformity, ulceration, persistent pain, or diabetic and neuropathic feet.