Operative Treatment of 2-fragment-fractures (AO 11-A3) of the Proximal Humerus in the Elderly: Cement Augmented Locking Plate Philos vs. Proximal Humerus Nail MultiLoc

Proximal humeral fractures are with an incidence of 4-5% the third most common fractures in the elderly. Compared to fractures of the upper limb it is the second most common fracture after distal radial fractures. 65% of all patients with a proximal humeral fracture are older than 60 years. Being aware of the demographic change there will even be an increase of incidence of these fractures. Kannus et al. showed an incidence of 298 per 100,000 in the at least 80 years old patients in 2007. Palvanen et al. predict an increase of incidence of 50% until 2030.

Approximately 80% of all humeral fractures are minimally or non-displaced and can be treated conservatively with a good functional result. In 20% of humeral fractures there is an indication for surgical treatment according to the modified Neer-Criteria. These criteria are fulfilled if there is an angulation of at least 45 degrees between fracture fragments, a displacement of the humeral shaft against the humeral head of at least 1 cm or a dislocation of the tuberculum of at least 5 mm.

Up to now there is evidence for superiority of any surgical treatment in literature. At the moment the most frequently used surgical technique for treatment of proximal humeral fractures is the angle stable plate fixation. There are various publications concerning this topic published by the investigators research group. In their 10-years results a majority of patients showed excellent and good, but also 16% showed unsatisfactory results after locking plate fixation. Main risk for poor outcome was revision surgery caused by secondary displacement (14%) which is also confirmed by results of other studies. In a further study investigators could show that there is a higher risk for secondary displacement in 2-part-fractures with a gross primary dislocation or a large metaphyseal fracture zone (AO 11-A3), especially in osteoporotic patients. More over these are common fractures and because of that a problem in surgical treatment.

A secondary varus dislocation of the head fragment and cutting-out are the most common complications of angle stable locking plates in AO 11-A3 fractures of the elderly. The primary reason for this mechanism of failure is certain instability of transmetaphyseal fractures in the region of the surgical neck caused by loss of impaction in a porous spongiosa. Because of that the forces on the head screws are high while the so called screw-bone-interface is rather weak after a surgical treatment.

Currently there exist various approaches to avoid a failure of the primary screw implantation. One possibility to increase the stability of the screw-bone-interface is the cement augmentation of the screw tips. To date there exist no clinical study that reports the results of locking plate fixation and the augmentation of cannulated head screws although it is a widely used method in everyday surgery, especially in the elderly.

A second possibility to prevent secondary displacement after surgical treatment of 2-fragment-fractures is the use of an intramedullary nails. A further development of intramedullary nails is multiplanar nailing. Screws can be inserted in various different levels and directions which can lead to a clearly higher stability.

A comparison of these two treatment options augmented locking plate versus multiplanar angle stable locking nail in 2-part proximal humeral fractures has not been carried out up to now.