Posterior instability of the shoulder after supracondylar fractures recovered with cubitus varus deformity.

Cubitus varus is a common complication after supracondylar fractures of the humerus, and there have been several discussions about the timing of correction of deformity. Although surgery is performed mainly for cosmetic purposes, the authors in this article show the relationship between cubitus varus and dislocation of the ulnar nerve and posterior instability of the ipsilateral shoulder with a Bankart lesion in three children. A special type of osteotomy to obtain three-dimensional correction was made. All shoulders were found to be clinically stable at follow-up with full pain-free range of motion. Corrective osteotomy of the distal humerus itself corrected the varus angulation and dislocation of the medial portion of the triceps in two patients and prevented the ulnar nerve from dislocating. The authors' experience illustrates the importance of biomechanics in understanding the pathoanatomy of cubitus varus; this deformity should not be regarded as a cosmetic deformity and should be treated early.