A "Hammer-Toe" deformity, describes a pathological condition of abnormal or exaggerated contracture at the metatarsal-phalangeal and inter-phalangeal joints of the toes. This is mainly due to an imbalance between the muscular flexors and extensors as well as intrinsic interossei and lumbrical muscles within the forefoot.
A hammer toe deformity may present as one of three morphological variations. A true hammer-toe deformity will exhibit dorsiflexion at the metatarsal-phalangeal joint and plantar flexion at the proximal interphalangeal joint. Whereas a mallet toe solely results from a plantarflexory contracture of the distal interphalangeal joint. A simultaneous combination of these two conditions is thus known as a claw toe.
Clinically, a hammer toe may present with hypertrophic callosities on the plantar surface of the corresponding metatarsal head and the distal/plantar tip of the toe in addition to a painful corn over the proximal interphalangeal joint.
A radiographic analysis of a hammer-toe deformity in the Anterior/Posterior or Dorsal/Plantar view will reveal a hallowed point or gun barrel appearance of the middle phalanx.
Although conservative care may involve shoe modifications, padding, strapping, and custom orthosis; surgical reconstruction may be required to alleviate painful and immobilizing hammer-toe conditions.
This surgical management of the hammer-toe deformity is performed by variable means of "Sequential Reduction." By this, a hammer-toe contracture is alleviated through various procedures in order to re-establish a functional position during active motion as well as rest.
This process may include, a lengthening of the extensor tendons, followed by a resection of the extensor hood. An "Arthroplasty" may be utilized to increase useable joint space within the proximal inter-phalangeal joint by removing the head of the proximal phalanx.
In more extreme deformities, a tenotomy of the flexor tendon may be utilized. This may be accompanied by a fusion of the joint itself, known as an "Arthrodesis," whereby the base of the middle phalanx and the head of the proximal phalanx are combined to form one continuous bone mass.
By balancing the forces of plantarflexion and dorsiflexion at the joints of the toe, a Hammer-toe operation may result in a drastic improvement of the functional mobility of the foot and leg during gait.