by Dr. Nathan D. Vela, DPM, MPH
Hammertoes are a condition when the digits are contracted in an upward position. In most cases the condition is aquired over time. This is a condition that causes the toes to contract and shorten often leading to the top of the toes rubbing against shoes and causing irritation and/or pain with closed shoes as well as activity. There are three types of causes for hammertoes. All three causes involved a breakdown in the mechanics of the lower extremities.
Why does this happen?
Usually occurs in individuals with flatfeet who excessively pronate during walking. Because there is no support of the midfoot bones from the flat foot condition, the flexor muscles started to contract earlier and longer than normally to try and stabalize the forefoot. The flexor tendons overpower the interosseus muscles of the foot and casue hammering or clawing of the digits.
This occurs with weakness of a muscle called the tricpes surae (calf muscle), The deep posterior leg and lateral leg muscles try to compensate for lack of plantarflexion. This causes an elevation of the arch creating a high arch and contracted digits. This cause is not as common.
The extensor muscles will activate to dorsiflex the ankle to allow the foot to clear the ground during the swing phase of gait (walking). Extensor substitution occurs the extensors of the digits gain a mechanical advantage over the lumbricles because the large muscle at the front of the leg called the Tibialis Anterior and the toes become contracted. This is the most common cause of hammertoes.
How is this treated?
Depending on the severity of the contraction of the toes, there is not a lot that can be done on a conservative level besides accomodationg the deformity with open shoes or shoes that have more room at the front of the shoes. Padding can be added to the top of the toe to prevent irritation. If the deformity is minor, strengthing the intrinsic muscles of the foot and the tibialis anterior may prevent worsening of the condition. If the deformity is severe, the treatment involves surgical correction of the deformity which varies depending which joint of the toe is contracted and whether or not it involves the metatarsal phalangeal joint which connects the toe to the foot. The correction also usually involves surgical hardware for fixation. Surgical techniques vary from arthroplasty which involves removing bone, joint fusion, or some surgeons will choose to use specialized toe implants.
Intraop Pics of Hammertoe correction
This patient had a bunion that is corrected. Also, the second toe overlapped the big toe. We have released the medial side to stop the pull towards the big toe. Below, we are putting in sutures on the lateral side to aid correction and maintenance of the reduction of the second toe joint.
After the repair of the 2nd MPJ, we perform a PIPJ Fusion and temporarily pin the second toe across the MPJ to allow healing of all bone and soft tissue. This pin is taken out in the office at approximately 6 wks.
Below, Pics of fixation of Weil Osteotomy
Weil osteotomy has been made and the 2 pins are temporarily fixating the second metatarsal head. The metatardsal head is shifted back 3-4 mm as can be seen by the lip of bone at the top.
The blue and gold screw are permanently fixing the bone and the 2 wires are then removed.
Final view of the Weil osteotomy. Due to the displacement and drift of the toe, the metatarsal head was shortened and shifted 2 mm to the side as can be seen by the ridge of bone to the left.
The following is depicting a bunion deformity of the great toe that has worsened a hammertoe contraction of the second toe. The outside deviation of the great toe caused underriding of the second toe which leads to increased dorsal (upward) dislocation of the toe.
Post-operative repair of the bunion and hammertoe deformities which straightens the great toe utilizing a combination of bone cuts and soft tissue releases of the great toe and second toe to correct abnormal position of the toes and significantly improve pain with activities and use of shoes.
Below is a photograph of a severe overlapping bunion and hammertoe deformity. At this point in the mechanical process the digits, especially the second digit, is dislocated from its articulation with the longer bone in the foot called the metatarsal. The severity of these deformities is multi-factorial involving genetics, altered mechanics with soft tissue contractures, and bad shoegear.
Below is a photograph of the front view of the same deformities that are pictured above.
Pictured below is the same foot after surgical correction of the bunion deformity of the great toe and hammertoe correction of the second, third and fifth toes. The plastic balls at the top of the second and third toe are covering wires that hold the position of the second and third toes into the longer bones (metatarsals) of the foot so that the soft tissue contractures heal in the correct place. Depending on the deformity, the wires will stay in place for a period of 4-6 weeks and then are removed.
Intraop pics of clinodactlyly before and during flexor release.