Oblique Lateral Closing-Wedge Osteotomy for Cubitus Varus in Skeletally Immature Patients.

BACKGROUND

We perform an oblique lateral closing-wedge osteotomy of the distal end of the humerus to correct cubitus varus deformity in children. This deformity is often the consequence of undertreatment, malreduction, or malunion of supracondylar humeral fractures. Although standard arcs of motion may be altered, cosmesis was traditionally considered a primary surgical indication. However, uncorrected cubitus varus leads to posterolateral rotatory instability of the elbow (PLRI), lateral condylar fractures, snapping medial triceps, and ulnar nerve instability. A contemporary understanding of these delayed sequelae has expanded our current indications. Detailed parameters predictive of late sequelae are needed to further specify surgical indications.

DESCRIPTION

We remove an oblique lateral closing wedge from the distal end of the humerus via a standard lateral approach. The osteotomy is angled away from the varus joint line such that lateral cortices after reduction lack prominence. Kirschner wires provide adequate fixation in young patients. In older children, extension is simultaneously corrected, and fragments are stabilized via plate osteosynthesis.

ALTERNATIVES

Patients who decline surgery are counseled regarding risks of delaying treatment until symptoms are present. PLRI manifests as lateral elbow pain or instability while rising from a chair. Once symptomatic, the lateral ulnar collateral ligament (LUCL) is irreversibly attenuated and morphologic changes in the ulnohumeral joint necessitate more extensive surgery to include distal humeral osteotomy, LUCL reconstruction, and possibly ulnar nerve transposition. Alternative osteotomy techniques are described and categorized as simple lateral closing wedge, step-cut, dome, 3-dimensional, or distraction osteogenesis. Simple closing-wedge osteotomies include a distal cut parallel to the joint line and retain a problematic lateral prominence (if the medial cortex is intact or the distal end of the humerus is not translated medially). Step-cut osteotomies theoretically minimize this lateral prominence while enhancing inherent stability. However, these additional cuts mandate wide surgical exposure despite similar outcomes. Three-dimensional planning employs computed tomography to create expensive anatomic cutting guides that address varus, extension, and internal rotation. However, residual internal rotation is generally well tolerated, derotation is associated with loss of fixation, and the extension deformity will successfully remodel in patients who are <10 years old. We employ 3-dimensional planning in skeletally mature patients with complex deformity and no remodeling potential.

RATIONALE

The oblique lateral closing wedge is ideal for skeletally immature patients because it is simple, reproducible, and efficient. It avoids the lateral prominence without increasing complexity or complications.