Soft Tissue Problems of Foot

Corns & Calluses:
Calluses represent dermatologic reaction to focal pressure. Ongoing pressure results in caluses developing into corns. Corns can be differentiated from warts when incised; Warts Will bleed, corns will not. The differential dx includes syphilis, psoriasis, lichen planus, rosacea, arsenic poisoning, basal cell nevus syndrome, & malignancy.

Treatment of corns is paring with a No. 15 blade to include removal of central keratin plug.
Plantar Warts:
Plantar warts are common, contagious, & caused by the human papillomavirus. The diagnosis is clinical & differential dx includes corns & undiagnosed melanoma.

Topical Tx with 15% to 20% salicylic acid is most effective. Non-healing lesions should be referred to a dermatologist or podiatrist.
Onychocryptosis (Ingrown toenail)
Onychocryptosis is characterized by increased inflammation or infection of the lateral or medial aspects of the toenail. This occurs when the nail plate penetrates the nail sulcus & subcutaneous tissue (usually in the great toe). Pts with underlying diabetes, arterial insufficiency, cellulitis, ulceration, or necrosis are at risk for amputation if treatment is delayed.

Treatment depends on the type of inflammation.
- If toenail is uninfected, sufficient results will often be obtained with elevation of the nail with a wisp of cotton between the nail plate and the skin, daily foot soaks, & avoidance of pressure on the area.
- A second option (requiring digital block) is to remove a spicule of the nail and debride the nail groove. If granulation tissue or infection is present, partial removal of the nail is indicated. If the toenail is infected, perform digital block and cut one-forth or less of the nail with a longitudinal incision (including beneath the cuticle). A non-adherent bulky dressing should be placed, and a would should be checked in 24-48 hrs.
Pathologic bursae of the foot are categorized as follows:
1. Non-inflammatory
2. Inflammatory
3. Suppurative
4. Calcified
Non-inflammatory bursae become painful as a result of direct pressure, whereas inflammatory bursitis results from gout, syphilis, or rheumatoid arthritis. Suppurative bursitis results from spread of pyogenic organisms (often staph. aureus) from adjacent wounds. Complications include hygroma, calcified bursae, fistula, & ulcer formation.

Treatment for severe septic bursitis include IV ABx such as Nafcillin 500 mg qid or oxacillin 500mg qid.
Plantar Fasciitis:
The plantar fascia is connective tissue anchoring the plantar skin to the bone protecting the arch of the foot. Plantar fasciitis is the most common cause of heel pain due to overuse. Pt have point tenderness over the anterior-medial calcaneus, that is, worse on arising & after activity. The ddx includes abnormal joint mechanics, poorly cushioned shoes, Achilles tendon pathology, & rheumatoid disease.

Tx includes Rest, Ice, & NSAIDs. Most cases are self-limited. Steroid inj. are NOT indicated in the ED. Severe cases may require a short-leg walking cast & should be referred to podiatrist or orthopedist.
Nerve entrapment Syndrome
Trasal Tunnel Syndrome
Tarsal tunnel syndrome involves heel & foot pain due to compression of the posterior tibial nerve as it courses inferior to the medial malleolus. Causes include running, restrictive footwear, edema of pregnancy, post-traumatic fibrosis, ganglion cysts, osteophytes, & tumors. Pain is worse at night & located at the medial malleolus, the heel, the sole, & the distal calf.

The differential Dx include planter fasciitis & Achilles tendonitis. Tinel sign is positive, & eversive & dorsiflexion worsen symptoms. The pain of tarsal tunnel syndrome involves the more medial heel & arch, & worsens with activity. US, CT, & MRI may aid in diagnosis.

Treatment includes NSAIDs, rest, & possible ortho referral.

Deep Peroneal Nerve Entrapment
Entrapment of the deep peroneal nerve occurs most frequently where it courses beneth the extensor retinaculum. Recurrent ankle sprains, soft tissue masses, and restrictive footwear represent the most common causes. Symptoms include dorsal & medial foot pain as well as sensory hypoesthesia at the first web space.

Pain & tenderness can be elicited by plantar flexion in inversion of the foot. Plantar fasciitis should also be considered. US, CT, & MRI may aid in diagnosis.

Treatment includes NSAIDs, rest, & possible Ortho referral.

A ganglion is a benign synovial cyst attached to a joint capsule or tendon sheath neat the anterolateral ankle.Typically a firm, non-tender, cystic lesion is found on examination. The diagnosis is clinical, but MRI or US can be used if in doubt.

Treatment includes aspiration and injection of glucocorticoids, but most require surgical excision.

Tendon Lesions
Tenosynovitis and Tendinitis: Tenosynovitis or tendonitis are usually due to overuse, and present with pain over the involved tendon.
Treatment include Ice, rest & NSAID

Tendon Lacerations: Tendon lacerations should be explored & repaired if the ends are visible in the wound. Due to the high complication rate, specialty consultation is recommended. After repair, extensor tendons are immobilized in dorsiflexion & flexor tendons inequinus.

Tendon Rupture:
Achilles tendon
rupture presents with pain & a palpable defect in the area of the tendon. Pt have an inability to stand on tiptoes, & an absence of plantar flexion with squeezing of the calf (Thompson test).
Treatment is generally surgical in younger pt & conservative (Cast in equinus) in the elderly.

Anterior tibialis tendon rupture results in usually chronic & presents with a flattened arc &swelling over the medial ankle. Examination may show weakness on inversion, a palpable defect, & inability to stand on tiptoes.

Flexor hallucis longus rupture presents with loss of plantar flexion of the great toe & must be surgically repaired in atheletes.

Disruption of the peroneal retinaculum occurs after a direct blow during dorsiflexion, and causes localized pain behind the lateral malleolus; there is clicking during walking, as the tendon is subluxed. Treatment is surgical.

Plantar Interdigital Neuroma (Morton Neuroma)
Neuroma are thought to occur from entrapment of the plantar digital nerve due to tight-fitting shoes; the 3rd interspace is most commonly affected. Pt often present with burning, cramping, or aching over the affected metatarsal head. Diagnosis is clinical, but US or MRI may be helpful.
Conservative treatment includes wide shoes & glucocorticoids injection. Local glucocorticoid injection may be curative. Surgical neurolysis is occasionally required. 
Compartment Syndrome
The foot has 9 compartments. Compartment syndrome in the foot are associated with high-energy crush injuries. Other causes include bleeding disorders & postischemic swelling after arterial injury, ankle fx, burns, & chronic overuse. Pt should be considered at-risk if there is increasingly severe pain exacerbated with active and passive motion, coupled with paresthesias or neurovascular deficits.

At-risk pt must have compartment pressures checked. Any difference of < 30 mm Hg between the stryker STIC Device and diastolic BP is considered positive. Prompt consideration of emergent fasciotomy.

Plantar Fibromatosis (Dupuytren contracture)
Plantar fibromatosis (Dupuytren contracture) involves small, asymptomatic, palpable, slowly growing, firm masses on the plantar surface of a (non-weight bearing) foot. MRI may be helpful for diagnosis.
Toe contracture does not occur. Lesions tend to reabsorb spontaneously, and treatment is conservative.
Malignant Melanoma
Melanoma of the foot, which accounts for 15% of all cutaneous melanoma, may present as atypical non-pigmented or pigmented lesions; the nail may be included. Vigilance is key as these lesions often mimic more benign conditions. The DDx includes fungal infections, plantar warts, & foot ulcers.

All typical or non-healing lesions should be sent for biopsy.