Outcomes and experience after open reduction for chronic Monteggia fracture in children

Background: The treatment of chronic Monteggia fracture-dislocation (CMF) remains controversial and challenging for surgeons. We describe our initial experience with ulnar osteotomy and angulation on correction with modified open surgery and evaluate outcomes from clinical and radiographic findings. Methods: We retrospectively reviewed 18 children with a mean age of 6.78 +/- 2.67 years old who underwent surgical treatment because of CMF. Electronic medical records of Bado type, complaints, Kim scores, and complications were recorded. Radiographic parameters of maximum interosseous distance (MID), proportional ulnar length (PUL), lengthening, and bending angle of the ulna were summarized. The final reduction statuses of the radial head were reviewed. Parameters were compared at the time of pre-operation and the last follow-up. The relationship between the lengthening and angulation of ulna and the interval was calculated. Results: The mean interval was 11.1 [1-48] months and the follow-up time was 46.6 [24-96] months. A good reduction was observed in 15 (83.33%) patients, while 3 (16.67%) patients were fair. Postoperatively, the Kim scores were improved, from 59.17 +/- 18.17 to 90 +/- 6.64 (P=0.000). The mean posterior bending angle was 12.88 degrees (range, 3 to 25 degrees), and the mean amount of elongation of the ulna was 8.78 mm (range, 3.61 to 17.52 mm). The lengthening of the ulna was proportional to the magnitude of angulation of the ulna (r=0.648, P=0.004), and a positive correlation was also seen between the lengthening and the interval (r=0.632, P=0.005) and the angulation and the interval (r=0.502, P=0.034). The PUL and MID were significantly increased from 1.06 +/- 0.03 and 1.11 +/- 0.26 to 1.13 +/- 0.11 (P=0.047) and 1.28 +/- 0.27 (P=0.021), separately. Conclusions: We highlight ulnar osteotomy as the essential procedure during reconstruction surgeries. Stabilization of the radial head with adequate elongation and balanced angulation of the osteotomy through direct observation is the main way to ensure and maintain satisfactory outcomes. With the extension of the interval, it is more necessary to increase the lengthening and angulation in positive proportion. PUL is a useful parameter in evaluating the mismatch between ulna and radius in CMF.