Fractures of the proximal humerus can offer a difficult surgical challenge particularly if they occur in elderly patients and/or are a complex fracture configuration. Much of the morbidity of the surgery relates to the extensile delto-pectoral approach traditionally used for operative treatment of these fractures.

A minimally invasive technique for approaching these fractures has was developed using a proximal deltoid split approach at the anterior edge of the deltoid and sliding a precontoured proximal humeral locking plate submuscularly after provisional fracture reduction. This technique was tested in a cadaver model to identify “safe” and “at risk” holes in the plate for percutaneous fixation in relation to the axillary nerve.

A case series of eighteen patients who had surgery using this technique were reviewed. All patients achieved acceptable reductions and went on to unite without any signs of AVN or implant failure. One patient had a transient sensory disturbance in an axillary nerve distribution post op. One patient has asymptomatic fibrous union of the greater tuberosity.

Minimally invasive plate fixation using a lateral deltoid split approach is technically possible with excellent results. The danger zone around the axillary nerve has been identified and should be avoided with percutaneous fixation utilising this procedure. A jig to allow accurate MIPO fixation has been developed.