Hinge plate technique for osteosynthesis of comminuted proximal humeral fractures.

Background: Several surgical techniques of osteosynthesis have been described for treatment of proximal humeral fractures. There is evidence that the quality of reduction improves the clinical outcome and decreases the number of complications. Reduction of the medial calcar is tricky when standard manoeuvres are performed. We have therefore augmented our standard surgical technique with a low-profile medial hinge plate which aims at better reconstructing the medial metaphysis without extensile soft tissue dissection in combination with proximal humerus locked plating.

Objective: Evaluate the radiological and clinical outcome after application of an augmented fixation with a low-profile medial hinge plate. We questioned: (i) The quality of reduction, (ii) The rate of complications, (iii) The clinical function in terms of the Oxford Shoulder Score (OSS).

Methods: A retrospective single-centre case series. Between 2016 and 2019, patients who had undergone open reduction and osteosynthesis by an anatomical locking plate associated with a 2.0 mm locking compression plate used as a hinge to support the medial metaphysis. Thirty-four patients, with an average age of 64 years had a clinical and/or radiological average follow-up of 36 months.

Results: The preoperative imaging identified three fractures in two parts, 19 fractures in three parts and 12 fractures in four parts. Seven cases with fracture-dislocation were identified, one head-split fracture, and 14 cases with a metaphyseal head extension of less than 8 mm. After comparing head-shaft displacement, cranialisation of the greater tuberosity as well as head-shaft alignment in the preoperative and postoperative radiographs, overall anatomical or near-anatomical fracture reduction was achieved in 27 of the patients. Only two cases presented postoperative complications. The two cases were complicated with nonunion without screw perforation requiring surgical intervention by re-osteosynthesis. The clinical outcome assessed by the OSS showed an average of 45/48. The age of the group with anatomical or near anatomical reduction and the group with at least one parameter of malreduction was significantly different, 65 and 74 years respectively (p<0.05). No significant differences were found when comparing the sex, surgical time, time to operation or the number of fracture parts.

Conclusion: The technique described provides a surgical treatment option with lower complication rates and a quality of reduction consistent with the current literature as well as a satisfactory clinical outcome.