Arthroscopic shoulder surgery for shoulder dislocation, subluxation, and instability: why, when and how it is done.

Edited By: Christopher J. Wahl, M.D., Suzanne L. Slaney, PA-C, ATC, MMS
Last updated Tuesday, January 25, 2005

Figure 1a

Figure 1b

Figure 2

Summary

Overview

Shoulder instability (also called subluxation) and shoulder dislocation are potentially painful and disabling conditions, and the treatments for these conditions vary widely depending upon the severity of symptoms and signs. Many patients will improve with the appropriate bracing and physical therapy. However, for those patients who require surgery, arthroscopic shoulder surgery should be used to both define and diagnose the exact nature of the joint instability. In most cases, the problem can be treated using specially-designed instruments working through very small incisions with a minimum of discomfort and without the need for a hospital stay.

The terms “instability”, “subluxation” and “dislocation” mean different things to different people. In addition, the term “shoulder instability” is a term that encompasses a vast spectrum of shoulder problems. In the simplest sense, the shoulder is like a “ball and socket” joint. Figure 1a shows the front view of a right shoulder. Figure 1b shows the view from behind of a right shoulder. For the sake of simplicity, the surrounding muscles and tendons are not shown, but the glenoid (socket) and humeral head are labled. Figure 2 shows an MRI view looking down through the shoulder joint from above. The glenoid and humeral head are labled. (Figures 1a and 1b are redrawn from Warner et al. Am J Sports Med 1992:20:675)

Subluxation and dislocation both represent problems that occur when the “ball” (or humeral head) doesn’t stay centered correctly in the “socket” (or glenoid). These problems may manifest themselves in a variety of ways; from pain with the normal activities of daily living, to the inability to lift the arm without dislocating the joint, and everything in between.

For many patients, the diagnosis is made in the emergency room after they have dislocated their shoulder during sports or an accident. Many other people who have subtle instability can be misdiagnosed as having “rotator cuff tear” or “bursitis”. An experienced shoulder surgeon or sports medicine surgeon can usually recognize the signs of shoulder instability. Often, the diagnosis is confirmed using Magnetic Resonance Imaging techniques (MRI), however many people can have a “normal MRI” appearance and debilitating symptoms—so a thorough clinical examination by an experienced orthopaedic shoulder surgeon is recommended. Video 1 shows a patient being examined prior to surgery. The right shoulder can be subluxed out of joint in the anterior direction. Note: Video may be slow to load on non-broadband internet connections. Modem users may wish to right click (or Command click for Macs) and save the file locally for viewing.

For many people, a conservative approach with physical therapy and a home-based strengthening program can resolve the pain or symptoms of instability. Those who do not improve with therapy, high-demand athletes, and overhead workers may require surgery to achieve a functional, painless range of motion. When surgery is required, it is of utmost importance that the surgeon look for and address all the potential causes of instability in the joint. If any of the factors contributing to instability is not addressed, the surgery will fail.

Arthroscopic shoulder surgery, or shoulder arthroscopy is a valuable tool to diagnose and treat shoulder instability and dislocation. Using the scope, an experienced surgeon can evaluate the entire shoulder joint and can usually treat the conditions leading to instability through very small incisions using specially-designed instruments and devices. In a small subpopulation of patients, a formal open surgery (using an incision about 3” to 5” long) will be required to correctly address the problem(s) encountered. The goal of surgery is to re-establish the stability of the humeral head in the shallow glenoid socket without compromising the shoulder range of motion. This is a delicate balance, and the results are most predictable in the hands of a highly-specialized surgical team that is familiar with the various techniques and instruments and who perform the surgery often. Such a team will maximize the benefits of the surgery and minimize the risks. The procedure can usually be performed within a few hours under general (or nerve block) anaesthesia, and the patient can be discharged to home with a minimum of discomfort. In addition, the scope allows the surgeon to take pictures and video to show to the patient what problem(s) existed and how the problem was addressed.

Patients undergoing arthroscopic shoulder stabilization require a limited period in a sling (usually 2- to 3-weeks) with some simple range-of-motion exercises at home. They will require fairly intensive outpatient physical therapy for re-establishing pain-free motion and strengthening the shoulder muscles for a few months. Normally, a person can return to most forms of normal activity within 6 weeks, and limited athletics between 10 and 14 weeks. A return to all activities and even contact athletics can usually be accomplished between 14 and 24 weeks, depending on the sport.

Downloads

• Video 1 - A patient being examined prior to surgery. (3.61 MB)

Surgery for shoulder dislocation, subluxation, and instability at the University of Washington

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