At a glance......
Morton’s Syndrome is the condition of a shorter first metatarsal in relation to the second metatarsal. It is a type of brachymetatarsia. The metatarsal bones behind the toes vary in relative length. For most feet, a smooth curve can be traced through the joints at the bases of the toes. But in Morton’s foot, the line has to bend more sharply to go through the base of the big toe, as shown in the diagram. This is because the first metatarsal, behind the big toe, is short compared to the second metatarsal, next to it. The longer second metatarsal puts the joint at the base of the second toe (the second metatarsal-phalangeal, or MTP, joint) further forward.
Morton’s neuroma (MN) is a compressive neuropathy of the common plantar digital nerve. It is a common compressive neuropathy often causing significant pain which limits footwear choices and weight-bearing activities.
The name derives from American orthopedic surgeon Dudley Joy Morton (1884–1960),[rx] who originally described it as part of Morton’s triad(a.k.a. Morton’s syndrome or Morton’s foot syndrome) [rx] a congenital short first metatarsal bone, a hypermobile first metatarsal segment and calluses under the second and third metatarsals. Confusion has arisen from “Morton’s foot” being used for a different condition, Morton’s metatarsalgia, which affects the space between the bones and is named after Thomas George Morton (1835–1903).
Morton’s neuroma is a compressive neuropathy of the interdigital nerve in forefoot due to compression and constant irritation at the plantar aspect of the transverse intermetatarsal ligament. It is not a true neuroma as the condition is degenerative rather than neoplastic. It is also referred to as Morton’s metatarsalgia, interdigital neuritis, Morton’s entrapment, interdigital neuralgia, interdigital neuroma, interdigital nerve compression syndrome, and intermetatarsal neuroma. The most common location for the neuroma is between the 2nd and 3rd metatarsals.[rx][rx][rx]
Causes of Morton’s Toe
Conditions and situations that can cause the bones to rub against a nerve include
- High-heeled shoes – especially those over 5 centimeters
- Shoes with a pointed or tight toe box – that squashes the toes together
- High-arched feet
- Flat feet – when the entire sole comes into contact with the ground
- A bunion – a localized painful swelling at the base of the big toe that enlarges the joint
- Hammertoe – a deformity within a joint of the second, third, or fourth toe that causes it to be permanently bent
- Some high-impact sporting activities – including running, soccer, tennis, karate, and basketball
- Injury or trauma to the foot
Symptoms of Morton’s Toe
Other symptoms include
- Burning pain – often described as like a “red hot needle,” which can start suddenly while walking
- Numbness may affect the toes
- Paresthesia, a tingling, pricking, or numbness with no apparent long-term physical effect, commonly known as pins-and-needles
- The sensation that something is inside the ball of the foot.
Diagnosis of Morton’s Toe
To specifically detect a potential Morton’s neuroma one has to perform the following clinical tests:
- Web-space tenderness test
- Squeeze test. While palpating the webspace, the examiner compresses the forefoot with his/her other hand. This can produce a painful, palpable ‘click’ (Mulder’s click – only considered true if a painful click).
- Plantar percussion test
- Toe-tip numbness. The opposing surfaces of the adjacent toes are examined for reduced sensation.
The diagnosis of Morton’s neuroma is based on clinical examination findings. Imaging studies can, however, contribute to confirmation of the clinical diagnosis, as well as size and site of the neuroma and to exclude other causes of pain, depending on the differential diagnosis.
- Plain – weight-bearing – foot radiographs are essential in patients with suspected Morton’s neuroma in order to assess the relative length of the metatarsals (‘forefoot cascade’) [rx] for reasons mentioned previously. At the same time one can detect or exclude stress fractures, degenerative changes, subluxation of the MTP joints etc.
- Ultrasound scan – [rx] in the hands of an experienced operator, is an excellent, dynamic and inexpensive diagnostic modality for Morton’s neuroma. The diagnostic process can be combined with a guided injection around the neuroma, the outcome of which can contribute to the diagnosis and can also often be therapeutic. An MRI scan [rx] can be highly sensitive and specific in diagnosing Morton’s neuroma. However, it is more expensive than ultrasound. It is probably superior if the patient does not have typical symptoms and other conditions are suspected, or if no musculoskeletal ultrasound expertise is available.
Treatment of Morton’s Toe
Nonoperative management is recommended initially. Physiotherapy, injections (local anesthetic, steroid, alcohol), cryotherapy, radiofrequency ablation, and shockwave therapy are discussed. Neuroma excision has been reported to have good to excellent results in 80% of patients, but gastrocnemius release and osteotomies should be considered so as to address concomitant problems.
Wearing a wide, soft-soled, laced shoe with a low heel can be effective in relieving pressure on the nerve. Some surgeons recommend a firm-soled shoe instead. Soft metatarsal support can help to spread the metatarsal heads. In the presence of synovitis, instability or deformity of the toe, a Budin splint or canopy toe strapping can decrease secondary neuralgia.
- Anti-inflammatory medications – Over-the-counter NSAIDs, such as ibuprofen and naproxen (Aleve) may help reduce pain and swelling. Your doctor may also advise prescription-strength anti-inflammatories.
- Tricyclic antidepressants – such as amitriptyline
- Anti-seizure medications – such as gabapentin have all been tried to lessen the severity of related nerve symptoms.
- Blind or ultrasound-guided steroid injections – can occasionally help, but their effect is rarely long-lasting.
- Corticosteroid combined – with local anesthetic injections is probably the most widely used interventional nonoperative treatment modality. Half of the patients may require surgery within two years and young age and neuroma size have been shown to be predictive factors.[rx]
- Alcohol injections – have only been shown to be effective in 30% of patients after five years, and can be associated with significant morbidity. One study has shown a treatment response of up to 60%, but mainly in patients under 55 years old.[rx]
- Ultrasound-guided radiofrequency ablation – is a novel treatment modality and short-term success rates of 80–85% have been reported.[rx,rx] Similarly cryoneurolysis has been shown to be effective in 15 out of 20 patients in the short term,[rx] whereas shockwave therapy has also been used for the management of Morton’s neuroma with positive results, compared to a placebo control group.[rx]
- High-dose Vitamin and B1, B6 and B12 – can reduce nerve Pain symptoms.[rx]
- Custom shoe accessories – Custom orthotics prepared by a specialist may help align your foot and ease the pain.
If pain persists, your doctor may recommend surgery. There are two common types of surgical procedures:
- Joint resection – A small portion of one of the toe joints is removed. The technical term for this is interphalangeal joint arthroplasty.
- Arthrodesis – An entire joint of the toe is removed and the bone ends are allowed to heal and rejoin themselves. The technical term for this is interphalangeal joint arthrodesis.
Morton’s neuroma responds well to rest, but if pain levels allow, some stretching and strengthening exercises may help to maintain and improve strength in the arch of the foot.
These include exercises to
- stretch the lower leg, calf, and Achilles muscles
- stretch the plantar fascia along the bottom of the foot
Exercise should start slowly, to stop the nerve from becoming inflamed again.
- To stretch the plantar fascia – take the heel in one hand and place the other hand under the ball of your foot and toes. Gently pull back the front of the foot and the toes toward the shin.
- Exercise by sitting with your feet out – in front of you and gently pulling the toes back toward the shin with the hand. In time, you may be able to pull the toes back without using the hand.
- To stretch the foot – roll it back and forth over a bottle on the floor.
- To strengthen the foot – make figure-of-eight patterns with the foot, leading with the big toe. Athletes might return to activity through a routine that gets gradually tougher.
- A physical therapist – might suggest walking for 4 minutes and jogging for 2 minutes, repeating four times on the first day, then, on the second day, resting. Exercising on alternate days, the athlete can gradually increase the time spent on more strenuous exercise. In 2012, a researcher reported that one patient experienced some relief from pain as a result of therapeutic massage. Six sessions of massage therapy were given, once a week, each lasting 60 to 75 minutes. The participant also completed the exercise described above to stretch the plantar fascia at home each day. The massage focused on postural alignment and treating the leg and foot. After three sessions, the patient reported that her pain had changed from burning and stabbing to dull and pulsing.
Self-help measures for Morton’s neuroma include
- Resting the foot
- Massaging the foot and affected toes
- Using an ice pack, wrapped in a cloth, on the affected area
- Using arch supports a type of padding that supports the arch of the foot and removes pressure from the nerve
- Wearing broad-toed shoes, to allow toes to spread out and reduce friction
- Taking over-the-counter (OTC) painkilling medications
- Modifying activities, for example, avoiding or taking a break from activities that put repetitive pressure on the neuroma, until the condition improves
- Managing or reducing bodyweight management, as this can improve symptoms in people with excess weight
- Doing strength exercises, to strengthen the foot muscles
Several types of orthotic devices or arch support, metatarsal pads or bars are available over the counter. These can be placed over the neuroma.
The Complication of Morton’s Toe
- Overpronation (turning inward) of foot
- Pain in the metatarsal area (ball of the foot)
- Stress fractures near or on the metatarsal
- Hammertoe, claw toe, and mallet toe
- Plantar fasciitis (pain in the heel or arch caused by overpronation)
- Bunions (bony protrusions) and Calluses (rough, thick skin patches)
- Morton’s neuroma (sensation of standing on a pebble or sharp object at the ball of the foot)
In addition to a greater risk for these associated foot problems, those with Morton’s Toe may also be more prone issues in the ankles, legs, hips, and back. This can include weakness or pain, shin splints, instability, arthritis, and more.