1 Principles top
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Fracture morphology
The unifocal type A fractures are considered extraarticular. It should be noted that a fracture line involving the metaphysis may reach the lowest part of the head.
Similarly, a fracture line involving the greater tuberosity may reach the uppermost part of the head. These features do not impair the articulation.
2 Reduction and preliminary fixation top
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Insertion of holding sutures
Holding sutures are inserted through the insertions of the musculi subscapularis, supraspinatus, and infraspinatus.
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Positioning of K-wires
Positioning K-wires for the plate are applied 5-7 mm underneath the tip of the major tubercle and 2-4 mm lateral to the bicipital groove.
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Reduction
Disimpaction of the head from the shaft, eg, using a bone spreader and some traction on the arm.
3 Reduction against the plate top
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Positioning of the plate
The holding sutures are now threaded into the plate. The plate is then positioned parallel to the bicipital groove against the humeral shaft.
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Reduction
The plate is fixed against the shaft with a cortical screw. Simultaneous reduction of the head fragment against the plate is achieved by pulling the arm, with additional use of the elevator and holding sutures.
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4 Fixation top
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Temporary fixation of the head fragment
Temporary fixation of the head fragment against the plate with threaded K-wires to ease C-arm control.
For this step the aiming device must be mounted.
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Fixation of the plate
The aiming device is fixed onto the PHILOS plate, and two threaded 2.5 mm K-wires are inserted through the guiding sleeves.
The K-wires are then fixed against the sleeve, either with external fixator clamps of the mini external fixator, or with special nuts. This allows for easy and reliable C-arm control.
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Definitive fixation
After anatomical reduction is achieved, definitive fixation is performed by inserting angular stable screws into the head fragment, and angular stable screws (bridge plating) or cortical screws (buttress plating) into the shaft segment In osteopenic bone, cortical screws are applied obliquely to gain better hold.
5 Pitfalls and pearls top
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Insufficient reduction
Insufficient reduction of the head against the plate will result in a varus position.
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Risk of impingement
Placing the plate without the use of the aiming device or a positioning K-wire 5-7 mm underneath the major tubercle results in too high plate position with a high risk of impingement.
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Maintaining reduction
Maintaining reduction can be difficult when the calcar is comminuted or when the head fragment tends to fall back laterally into the medullary canal, or medially into varus.
A K-wire placed along the calcar into the head fragment helps to hold the head fragment in place before the plate is applied.
The K-wire is removed after plate fixation.