Minimally invasive plate osteosynthesis for proximal humeral fractures: Clinical and radiologic outcomes according to fracture type

Background: This study evaluated the clinical and radiologic outcomes, according to fracture type, of proximal humeral fractures treated by the minimally invasive plate osteosynthesis (MIPO) technique. Materials and methods: Of 85 patients with proximal humeral fractures who were treated by the MIPO technique, 62 were evaluated: 27 with 2-part fractures, 24 with 3-part fractures, and 11 with 4-part fractures. An additional inferomedial screw or fibular allograft was used when severe medial cortical comminution was found in the proximal humerus. Clinical and radiographic outcomes were evaluated during the follow-up of 37months. Results: There was a significant difference in the Constant scores of patients with 4-part fractures compared with those with 3-part fractures ( P=039). The neck-shaft angle in 4-part fractures (121°±3°) at final follow-up was significantly lower compared with other fracture types (2-part: 129°±9°, P=036; 3-part: 129°±2°, P=031). Complication rates (72.7%) of 4-part fractures were significantly higher than with other fracture types (2-part, 7.4%; 3-part, 20.8%; P=001). Sixteen fractures were fixed with an additional inferomedial screw, and 3 patients had insertion of a fibular allograft. Conclusion: Satisfactory clinical and radiologic outcomes were obtained by the MIPO technique in proximal humeral fractures. In addition, medial cortical support can be performed with an inferomedial screw or fibular allograft in the MIPO technique. However, the MIPO technique for 4-part fractures showed relatively inferior outcomes compared with 2- and 3-part fractures. Conversion to open plating is also considered if adequate reduction, that is, a neck-shaft angle >120°, is not able to be obtained in the MIPO technique for 4-part fractures of the proximal humerus.