An imbalance between the extrinsic and intrinsic muscles of the foot can produce deformities of the lesser toes. These include so-called claw toe deformity and hammer toe deformity. Both are characterized by a prominent bump of the flexed proximal interphalangeal joint, made more prominent by extension of the metatasal-phalangeal joint; in the claw toe, the distal interphalangeal joint is flexed (producing "clawing"), whereas in hammer toe deformities the distal interphalangeal joint is extended. In a mallet toe, the MTP and PIP joints are extended and the DIP joint is flexed
Structure and function
The lesser toes have three phalanges. The proximal phalanx articulates proximally with the metatarsal (at the MTP joint) and distally with the middle phalanx (at the PIP) joint; the middle phalanx’s articulation with the distal phalanx is called the DIP joint.
The extensor digitorum longus (EDL), a so-called extrinsic muscle (ie, it originates in the leg), is the primarily extender of the MTP joint. The extensor digitorum brevis (EDB) originates in the foot (hence an intrinsic muscle of the foot) extends the PIP and DIP joints.
The flexor digitorum longus (FDL) also originates in the leg flexes all three joints of the lesser toes, but the DIP joint especially. The flexor digitorum brevis (FDB) tendon originates in the foot and primarily flexes the PIP joint.
In the foot, all of the toe joints have a fibrocartilaginous plantar plate, which passively resist extension as well.
The lumbricals originate from the metatarsals flex the MTP joint and extend the PIP and DIP joints.
Figure : ANATOMY DIAGRAM?
Claw toes are caused by an imbalance between the extrinsic foot muscles, originating from the lower leg, and the intrinsic muscles in the foot, causing flexion at the PIP (proximal interphalangeal) joint and extension at the MTP (metatarsal phalangeal) joint. The PIP joints become prominent and can be irritated by shoes, leading to painful calluses on the dorsal aspect of the toes (Figure 3).
Figure : Claw toes. The second toe is usually the most pronounced deformity, but all four lesser toes demonstrate clawing.
Typically, when only a single toe is clawed, trauma or arthritis in the cause. If all four lesser toes are involved, nerve damage caused by diabetes or alcoholism may be to blame.
Hammer toes are usually caused by shoes that force the toe to bend; they are also seen in patients with bunions.
A mallet toe, ie isolated flexion of the DIP joint, may be caused by shoe pressure (causing, eventually, attenuation of the extensor tendon); a tight flexor digitorum longus can also be the cause
A patient with a deformity of the lesser toes is very likely an older female presenting with pain on the top of the toes (as they rub against the shoes). There also can be pain on the tip of the toes as they jam into the soles of the shoes. With a long-standing deformity, there can be pain at the base of the toes along with corns or calluses of the skin from repeated friction
The deformity is usually obvious, and xrays would only confirm what is seen clinically, On physical exam, each joint should be assessed as to whether it can be passively corrected; that is whether the deformities are flexible or fixed (as this guides treatment). It is also important to assess the toes in various positions of ankle flexion/extension, so the effect of any extrinsic muscle tightness can be demonstrated (ie, tightness of the extrinsic flexors would be worsened with ankle dorsiflexion.) Also, because toe deformities are seen as a manifestation of neurological disease, a detailed assessment of strength and sensation is needed.
Claw toes can be congenital or acquired, and so are seen throughout all ages, though more common with increasing age (the 7th and 8th decades). Women are affected four to five times more than men.
Underlying etiologies or associated conditions include:
- diabetes, with peripheral neuropathy
- rheumatoid arthritis
- primary neuromuscular disease (poliomyelitis, Freidrich's ataxia, myelopathy, multiple sclerosis or Charcot Marie Tooth Disease
- other foot deformities such as bunions, flat feet, or pes cavus deformity (highly arched feet)
All lesser toes deformities are red flag findings, suggesting the presence of a complication of diabetes or a neurological disorder. Close evaluation of the whole patient is essential.
Treatment options and outcomes
Most deformities can be treated by applying pads to the areas of prominence or using a shoe with a wide-toe box to accommodate the deformity and alleviate pain. Some patients may need an orthotic to create cushioning over the toe region. Trimming painful calluses can relieve symptoms, but without addressing the deformity, they may recur.
Surgery is considered in deformities that cannot be corrected non-operatively.
Claw and hammer toes with a flexible deformity may be treated with a flexor to extensor tendon transfer with a capsular and extensor tendon release. If there is a fixed deformity at the MTP joint, a capsular release and extensor tendon lengthening usually suffices, but a metatarsal shortening osteotomy may be needed. A fixed PIP deformity is treated with resection arthroplasty or Interphalangeal fusion.
A mallet toes with a flexible deformity can be treated with a percutaneous flexor tenotomy if the deformity is flexible; a rigid deformity requires either a resection arthroplasty of the distal aspect of the middle phalanx or DIP fusion
Note that the recovery period for any toe surgery is prolonged. It is not uncommon to note swelling and stiffness in the toes even 6 months post-surgery.
Foot surgery, in general, is more susceptible to wound complications; toe deformity surgery, in particular, can be complicated by recurrence of the deformity.
claw toe, hammer toe, mallet toe, Metatarsalgia, corns, push up test, muscular imbalance
Claw/hammer/mallet toes are typically an indication of an underlying neurological or muscle disorder—asking the right questions to the patient and ordering the necessary exams to identify the cause is important.