- Discussion:
- forefoot is most commonly affected portion of rheumatoid foot;
- forefoot deformities include:
- claw toe or hammer toe of lateral four toes;
- severe hallux valgus
- plantar keratosis beneath subluxed or dislocated MTP joints;
- distal migration of the fat pad (which follows the toes);
- Dorsal Approach:
- modified technique involves metatarsal head trimming or resection thru a dorsal incision w/ or w/o excision of all or part of the
proximal phalanx may resolve the symptoms;
- two longitudinal incisions are made in the 2nd and 4th interspaces;
- collateral ligaments, the dorsal aspect of the capsule, the plantar plate, and the interossei are released in a circumferential fashion around
the base of the proximal phalanx and the head and metaphysis of the metatarsal;
- long extensor tendon is left intact;
- metatarsal head resection:
- improve exposure of metatarsal head by clearing the base of the proximal phalanx and by distracting on the phalanx;
- bone cutter is used to transect the second metatarsal in the region of the distal metaphysis;
- it is essential that the metatarsal heads be transected in a distal-dorsal to plantar proximal direction;
- larger amount of bone needs to be resected w/ more severe overlap of proximal phalanx on the metatarsal head;
- goal is to create about 1 cm of space between the metatarsal neck and base of proximal phalanx;
- after resection of the second metatarsal, remaining metatarsals should be progressively shorter by several mm (from 2nd to the 5th);
- failure to achieve a nice cascading of the metatarsal, may result in metatarsalgia;
- attempt to preserve the base of the proximal phalanx at the MP joint (preserves the alignment and relocation of the lesser MP joints);
- subsequent in the operative procedure the hammertoe deformities are fixed with a K wire that is also driven across the relocated MTP joint which provides stability;
- another technique involves longitudinal "Y" incisions between the 2nd and 3rd and between the 4th and 5th metatarsal heads, so that a
Webbing procedure can be performed on the lesser toes;
- w/ more severe deformity, (w/ dislocation of the metatarsal heads) it may be necessary to resect the proximal bases of the lesser toes;
- w/ more severe deformity, a more extensive Webbing procedure may have to be performed, usually past the region of phalangeal
resection, to prevent drifting of the digits;
- hammertoe deformities:
- typically there will be a moderate or severe deformity which will require resection of the distal condyles of the proximal phalanx, and
subsequently the proximal articular surface of the middle phalanx is excised;
- if there is any question of soft tissue viability, then closed osteoclasis of the fixed PIP joints of the lesser toes is performed,
followed by temporary pin fixation;
- K wire is driven across the joint (retrograde technique) w/ the joint in a slightly flexed position and is subsequently driven on across
the MTP joint;
- 1st MTP Fusion:
- great toe should be no more than 2 mm longer than the second toe;
- Plantar Approach:
- alternatively metatarsal heads can be resected thru a plantar incision, but this approach does not allow a clean dissection and may be
associated w/ distasteful bleeding once the tourniquet is released