Rockwood Adults CH34

1101

CHAPTER 34 • Glenohumeral Instability

A

B

Figure 34-37.  A: After the horizontal split of the subscapularis muscle fibers and the glenohumeral joint is exposed. A threaded screw tap ( blue arrow ) is inserted into the coracoid base to help retract the scapula and allow better angle to drill the two holes into the anterior glenoid neck. B: The first inferior hole is predrilled into the glenoid neck about 5 to 6 mm off the rim. A 5-mm partially threaded screw is put into the coracoid, and using the screw driver ( yellow arrow ), it is fixed down to the glenoid. The second hole is subsequently drilled and the second screw inserted. C: Both screws are tightened over the coracoid and the glenoid fossa is flush to the surface of the coracoid.

C

freed. Using a three-prong sharp grasper, the inferior surface of the coracoid is exposed. Using the same oscillating saw, the undersurface is flattened for preparation to transfer it to the anterior glenoid rim. Two evenly spaced holes are drilled into the coracoid with a 2.7-mm drill bit (Fig. 34-36D). A humeral head retractor is placed in the glenohumeral joint to retract the humeral head. Curved cobra retractor is used inferiorly under the glenoid rim to retract the axillary nerve and subscapu- laris muscle. Anterior glenoid neck retractor is placed medial on the glenoid neck. A Steinmann pin is malleted into the glenoid fossa superiorly to retract the superior subscapularis muscle. A large pineapple burr or curved osteotome is used to flat- ten the anterior-inferior glenoid for preparation of the cora- coid transfer. It is crucial that this surface is flat to allow for full contact between the undersurface of the coracoid and the anterior glenoid rim. The first hole (2.7-mm drill bit) is drilled into the neck of the glenoid about 5 to 6 mm medial to the gle- noid surface. The authors like to use a metal tap into the base of the coracoid to help externally rotate or retract the scapula

(Fig. 34-37A). This maneuver will allow the drill hole to be parallel to the glenoid fossa. A 30-mm partially threaded 5-mm osteopenia screw is placed into the inferior hole in the coracoid, and using a screw driver, the graft is placed on the anterior glenoid rim and the screw is used to hold the graft (Fig. 34-37B). Using the 2.7-mm drill bit, the second hole is drilled from the coracoid to the back of the glenoid rim. A depth gauge is used to measure the exact size of the screw length. Another partially threaded 5-mm screw is placed to complete the final fixation of the coracoid to the anterior glenoid rim (Fig. 34-37C). Alternatively, if the coracoid is small, two 3.5 fully threaded screws put in with lag-by tech- nique can also be used for fixation. The capsule to the CA ligament is repaired with 0 Vicryl sutures. The subscapularis split is also repaired with 0 Vic- ryl sutures in an interrupted fashion. Deltopectoral interval is closed with running no. 2 sutures and skin closed with 3-0 Monocryl and Dermabond. The patient is placed in a sling and abduction pillow. Standard postoperative protocol is utilized.