Metatarsal Lengthening

Relatively short metatarsal (brachymetatarsia; Fig. 20.1 )

Overload/transfer metatarsalgia to an adjacent metatarsal head

Short first metatarsal (1MT) following corrective surgery for hallux valgus

Short metatarsal clinically and radiographically, based on weight-bearing examinations

• Radiographic evidence of short fourth metatarsal (4MT; brachymetatarsalgia)

• Radiographic evidence of short 1MT following corrective surgery for hallux valgus ( Fig. 20.2 )

  

Adjacent metatarsal heads may have tenderness and callus formation from overload

Determine associated elevation of the affected metatarsal head.

Determine the amount of metatarsal shortening (i.e., the amount of lengthening required).

Assess prior surgical scars for preoperative planning.

Identify exact location of tarsometatarsal (TMT) joints for planning of pin placement.

• Adjust the external fixator relative to the 1MT ( Fig. 20.3A ).

  

• Define the location of the first metatarsophalangeal (MTP) joint ( Fig. 20.3B ).

• Define the location of the first TMT joint ( Fig. 20.3C ).

At-risk structures include the following:

• 1MT: the dorsomedial cutaneous sensory nerve to the hallux and the extensor hallucis longus tendon, as can be seen in Fig. 20.4A .

  

• 4MT: lateral branch of the superficial peroneal nerve and the extensor digitorum longus tendons, as can be seen in Fig. 20.4B .

Assess-associated MTP joint deformity (claw toe or varus/valgus deviation); this associated deformity will not be corrected with metatarsal lengthening unless an adjunctive procedure is performed.