Does overcorrection cause any negative effect on pediatric missed Monteggia lesion?

To evaluate the outcome of different types of ulna osteotomy in missed Monteggia fracture with a particular interest in anatomical correction and overcorrection techniques. The outcome between the two groups were compared on aspects of (1) clinical outcome (2) radiologic outcome.

Twenty-one patients with type 1 missed Monteggia fracture who underwent surgery between January 2005-2018 were retrospectively reviewed. The patients were divided into two groups according to the degrees of correction: group 1 anatomical correction (no ulnar dorsal angulation) and group 2 overcorrection (degrees of ulnar dorsal angulation ≥ 10°). Clinical outcomes were assessed using the Kim elbow performance score. Radiologic outcomes were categorized into four groups with regard to the radial head: excellent (complete reduction), good (slight subluxation), fair (moderate subluxation), and poor (dislocation).

Eleven patients with anatomical ulna osteotomy and ten patients with overcorrection ulnar osteotomy were enrolled with a mean age of 7.95 (5-12) years at the time of operation. The mean duration from injury to surgery was 27.05 (3-120) months, and the mean period of follow-up was 29.90 ± 22.37 (12-84) months. The average angle of total correction measured in group 1 was 6.09° (3°-9°) and 28.37° (12°-40°), in group 2. Fair-to-poor radiological outcomes at the last follow-up were more frequently observed in overcorrection group (40% vs. 0%) (p = 0.035) as well as clinical outcome (20% vs. 0%) (p = 0.214). Among the patients in group 2, posterior dislocation was diagnosed in two patients at 18 months and 2 months after surgery.

The postoperative result of overcorrection ulna osteotomy showed significant inferiority in radiologic outcome compared to anatomical correction. Overcorrection of ulna osteotomy could be associated with posterior dislocation of radial head.