Posterior glenoid osteoplasty for unstable dislocating shoulders. Surgery to build up the back of the glenoid socket using an osteotomy and graft can restore shoulder anatomy and lessen pain and improve function.

Edited By: Frederick A. Matsen III, M.D., Winston J. Warme, MD
Last updated Monday, October 09, 2006

Figure 7 - A six-centimeter incision is based on the major posterior axillary crease

Figure 8 - The posterior deltoid is split between its posterior one third and its anterior two thirds beginning two centimeters medial to the posterior corner of the

Figure 9 - The split is deepened to expose the posterior rotator cuff muscles

Figure 10 - The dissection of the posterior rotator cuff muscles is facilitated by externally rotating the arm

Figure 11 - Looking at the shoulder with the deltoid muscle reflected, we can see the axillary nerve exiting the quadrilateral space (between the long head of the triceps, the humeral shaft, the teres minor and the teres major). The shoulder capsule is approached as indicated by the dotted line between the infraspinatus and the teres minor. The teres minor protects the axillary nerve during the procedure.

Figure 12 - The posterior glenohumeral capsule is exposed and inspected. Often a defect or very thin portion of the capsule can be identified

Figure 13 - A horizontal incision is made in the thinnest part of the capsule

Figure 14 - Through the posterior capsular opening a blunt elevator is inserted into the joint to determine the plane of the glenoid

Figure 15 - The plane of the intended glenoid osteotomy is determined parallel to and one centimeter medial to the articular surface

Figure 16 - The plane of the intended glenoid osteotomy is determined parallel to and one centimeter medial to the articular surface. A drill hole is made from anterior to posterior in the plane of the intended osteotomy. The depth of this hole is measured with a depth gauge, revealing the anteroposterior dimension of the glenoid in the plane of the intended osteotomy. A 3/4 inch flat and strong osteotome is marked with sterile tape at a length equal to 3/4 of the anteroposterior dimension of th

Figure 17 - The depth of the osteotome is controlled by paying attention to the sterile tape mark

Figure 18 - The osteotome is inserted with a slight posterior inferior to anterior superior angulation

Figure 19 - A posterior inferior opening wedge osteotomy is created one centimeter medial to the glenoid lip in the same as the face of the glenoid articular surface. The depth of the osteotome is controlled by paying attention to the sterile tape mark. This osteotomy is opened with successive levering steps to ?bend? the bone, rather than breaking. The glenoid surface is observed as the osteotomy is deepened to prevent penetration of the joint surface.

Figure 20 - The bone graft is harvested using an oscillating saw

Figure21 - A 20 mm x 20 mm x 6 mm bone graft is harvested from the posterior superior scapular spine

Figure22 - The bone graft is fashioned to a 20 mm x 15 mm x 5 mm wedge using a pine cone burr

Figure 23 - The wedge-shaped graft is inserted into the osteotomy so that its cortex is just inside that of the posterior glenoid

About the procedure

Technical details

Posterior glenoid osteoplasty is a highly technical procedure; each step plays a critical role in the outcome.

The goal is to perform this surgery without detaching muscle or tendons--this ?rotator cuff on? approach speeds the recovery because strengthening exercises can be started right away after surgery.

After the anesthetic has beena dministered, the patient is placed prone on the operating table, and the shoulder has been prepared, a cosmetic incision is made in a natural skin crease at the back of the shoulder (see figure 7).

This incision allows access to the seam between the posterior and middle thirds of the deltoid (see figure 8). Splitting this seam allows access to the rotator cuff muscles without detaching or damaging the important deltoid muscle, which is responsible for a significant portion of the shoulder's power (see figure 9). All scar tissue is removed from the space beneath the deltoid.

The posterior rotator cuff muscles are relaxed by passive external rotation (see figure 10). The interval between the infraspinatus and the teres minor is split, leaving the teres minor between the split and the axillary nerve (see figure 11). This split is opened without any tendon detachment providing excellent exposure of the posterior shoulder capsule (see figure 12). The capsule is incised horizontally (see figure 13). If there is a weak area of capsule the incision is made through it, so that it can be reinforced at the time of closure. A blunt elevator is inserted to indicate the plane of the joint (see figure 14). The posterior glenoid bone cut is planned one centimeter medial to the joint surface and parallel to it (see figure 15). A drill hole is made in the plane of the intended cut and the depth of this hole is measured. The osteotome is marked with sterile tape at a distance equal to three fourths of the depth of the glenoid at the osteotomy site (see figure 16).

The osteotome is driven into the glenoid, parallel to the joint surface, down to the level of the tape marking three quarters of the anteroposterior distance of the glenoid (see figure 17). The osteotome is inserted in a posterior inferior to anterior superior direction (see figure 18). The osteotomy is opened by successive prying (see figure 19).

Through the same skin incision, a 20 mm by 20 mm by 6 mm bicortical graft is harvested from the posterior acromion using an oscillating saw (see figures 20 and 21). Using a power burr, the graft is fashioned into a wedge measuring 20 mm by 15 mm by 5 mm. The graft is then inserted into the opened osteotomy at the back of the glenoid (see figure 22). The graft is driven in until it is just below the surface of the bone of the glenoid--this securely locks it in place (see figure 23).

The capsule split is closed, reinforcing any weaknesses.

The deltoid split is repaired side to side and any detachment of the deltoid from the posterior spine of the scapula is repaired to bone.

A cosmetic closure of the skin incision is carried out, dressings are applied, and the arm is placed in a sling.

Anesthetic

Length of posterior glenoid osteoplasty

Surgery for posterior shoulder instability at the University of Washington

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