These fractures produce separate fragments of the proximal humerus: an epiphyseal (humeral head) fragment and one or both tuberosities in addition to the shaft. Reduction involves repositioning the humeral head, and also restoring the tuberosities to their proper location.
The medial periosteum (medial hinge) is not ruptured. Much of the remaining periosteum (especially laterally) may also be intact
As a first step perform a closed reduction taking advantage of the intact soft-tissue sleeve (as with ligamentotaxis). Frequently, the displaced fragments will snap into position with this maneuver.
Valgus forces (abducting at the fracture) can be applied to the lateral aspect of the humeral shaft to correct the varus deformity and facilitate manual reduction.
Periosteal elevator and/or bone hook
If closed reduction is unsuccessful, minimally invasive open reduction can be attempted through a small transdeltoid incision using appropriate instruments.
Periosteal elevators or punches can be used to disimpact and reposition fracture fragments.
If the reduction is not adequate, a similarly inserted bone hook may aid reduction of the tuberosities.
Protect the axillary nerve on the deep surface of the deltoid muscle, 6 cm below the acromion.
Adequate reduction has been achieved if the tuberosities come to lie laterally flush or slightly underneath the elevated humeral head.
Check reduction by image intensification.
Temporarily fix the tuberosities with K-wires placed outside the intended plate location, as illustrated in this case for a 4-part fracture.