Shoulder instability can be very complex ranging from painful loss of motion to shoulder dislocation. Surgery to restore a pain free, stable joint requires careful examination by the surgeon. Before a decision can be made what surgical technique should be used, it is important to identify whether the patient has a unidirectional or multidirectional instability.
A unidirectional instability means the shoulder has too much movement in one direction only. Multidirectional instability refers to a shoulder joint that has too much movement or laxity in several different directions at the same time.
Most of the time, this type of problem is caused by laxity or looseness of the shoulder capsule or damage to the capsule and labrum. The labrum is an extra rim of cartilage around the shoulder socket designed to give it a little more depth and holding power.
There is a difference between laxity (looseness of the soft tissues holding the shoulder together) and instability (abnormal increase in capsular volume). When it comes to surgery, the surgeon must understand the difference AND recognize when patients have one or both of these conditions. The surgical procedure selected must specifically address the problem(s).
Treatment can begin with conservative (nonoperative) care. This consists of a rehab program of rotator cuff strengthening exercises, scapular stabilization, and therapy to restore normal proprioception (joint’s sense of position). A physical therapist will set up and supervise the program. The therapist pays close attention to helping the patient restore normal motor control, strength, endurance, and stability.
If a nonoperative approach fails to restore shoulder stability, then surgery to correct the capsular laxity may be required. In the case of multidirectional laxity, the surgeon will reduce the excessive volume by “tightening up” the joint. This may involve shifting the capsule and increasing tension on the shoulder ligaments. Sometimes it is best to make an incision or cut straight down the capsule, draw the edges closer together and suture them back together.
After surgery, shoulder rehab is important. During the first six weeks, the patient wears an immobilizer to protect the healing tissue and does pendulum (Codman) exercises to keep the joint moving without disrupting the incision site. Six weeks after surgery, a rehab program of stretching and strengthening program is started.
Most of the time, this approach is successful but there are cases where surgery fails to achieve the desired results. Failure is most likely when the surgeon does not address the specific type of capsular laxity present. Other risk factors for a failed stabilization procedure include untreated lesions, stretched ligaments, bone loss, or compression fracture of the shoulder glenoid surface. The glenoid is the shallow shoulder socket.
A failed result after shoulder stabilization surgery is not the end of the line. Revision surgery can be done to address the ongoing laxity or instability. The decision to perform arthroscopic versus open shoulder surgery depends on the surgeon’s experience and the exact nature of the patient’s problem(s).
Once again, it is very important that the surgeon re-evaluate the patient and make sure all aspects of the problem have been identified. There are fewer problems after revision stabilization procedures when the patients are young (less than 35 years old), have good bone density, and have not had other previous shoulder surgeries.
Details of surgical technique described here along with figures depicting the surgical procedures are available in an instructional course lecture. This lecture was sponsored by the American Academy of Orthopaedic Surgeons. The surgeons who wrote the article are from the University of Texas in San Antonio, Texas. They suggest that results after a capsular shift procedure are good to excellent.