Easley_CH066.indd

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Chapter 66 Supramalleolar Osteotomy with Internal Fixation: Perspective 2

T E C H N I Q U E S

TECH FIG 11 ● (continued) C. Image after correction of the deformity. Note the electrocautery markings on the tibial cortex ( asterisks ) and the 2.5-mm K-wire in the medial malleolus ( arrow ) which was used as a joystick to correct the deformity and then for preliminary fixation of the correction. D. Preoperative ( left ) and postoperative radiographs of a 46-year-old patient with congruent varus arthritis of his ankle joint. The correction was fixed with a T-shaped plate for the tibia and a third tubular plate for the fibula. C D

■ The fibula is exposed through a separate lateral incision and then osteotomized as described in the section Fibular Osteotomy. ■ The osteotomy is mobilized, the deformity corrected as preop- eratively planned, and a 2.5-mm K-wire introduced from the medial malleolus to preliminarily secure the correction.

■ The correction of the tibia is secured with one T-shaped plate or two straight (one medial and one lateral plate) plates with interlocking screws. ■ The length and position of the fibula is then adjusted under fluoroscopic control and the fibula secured with an additional plate or with two screws ( TECH FIG 11D ).

PEARLS AND PITFALLS

Laceration of the posterior tibial tendon

■ For lateral osteotomies and dome-shaped osteotomies in posttraumatic cases with extensive scarring on the posteromedial aspect of the ankle, it may be necessary to expose the tendon through a minimal incision to protect it. ■ This loss of the hinge mechanism of the far cortex introduces the risk for rotational or translational malpositioning and postoperative displacement of the osteotomy. ■ Consider additional fixation with a second plate in a second plane. ■ In select cases, the syndesmosis needs to be mobilized to maintain congruent tibiotalar joint alignment. We do this by releasing the anterior syndesmotic ligaments from the anterolateral distal tibia, imme- diately proximal to the ankle joint. The ligaments are released by removing Chaput tubercle from the anterolateral distal tibia using an osteotome or chisel. Once the osteotomy is secured and the fibula is reduced to the desired position to create a congruent ankle joint, the syndesmosis is stabilized at its new resting tension by reattaching Chaput tubercle with a screw and a washer or with transosseous sutures. ■ The risk can be lowered by using implants that provide angular stability and by leaving a hinge of bone and periosteum at the far cortex when performing the tibial osteotomy to achieve a controlled correc- tion in the desired plane.

Accidental cutting through the entire tibia in wedge osteotomies

Mobilization of the syndesmosis

Loss of reduction of the osteotomy