Does overcorrection cause any negative effect on pediatric missed Monteggia lesion

PURPOSES: 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. METHODS: 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 degrees ). 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). RESULTS: 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 degrees (3 degrees -9 degrees ) and 28.37 degrees (12 degrees -40 degrees ), 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. CONCLUSION: 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.