Successful arthroscopic shoulder instability repair requires a carefully devised surgical plan focused on several technical aspects of the procedure, according to one expert.
“Management of glenohumeral instability is one of the most challenging pathologies that shoulder surgeons encounter.”
That is the assessment of Walter B. McClelland, Jr., MD, FAAOS, an orthopedic surgeon specializing in hand, shoulder and elbow surgery at Atlanta’s Peachtree Orthopedics, writing for American Academy of Orthopaedic Surgeons (AAOS) news magazine AAOS Now. Dr. McClelland serves as the current chair of the AAOS Shoulder & Elbow Evaluations Committee and is president-elect of the Georgia Shoulder & Elbow Society. In a recent article for the magazine, Dr. McClelland points to the variability in patient anatomy and overall health as testing factors for surgeons when treating shoulder instability. This condition is characterized by complete or partial dislocation of the joint, often due to trauma or overuse.
If conservative treatment proves ineffective or is not indicated, surgeons may choose to perform open or arthroscopic repair. The latter is challenging and once had higher rates of recurrent instability, according to Dr. McClelland, but it has now achieved parity with open repair. In a 2017 study published in The Open Orthopaedics Journal, researchers in Portugal note that “[i]n a recent systematic review, the rate of recurrent instability after arthroscopic procedures was not statistically different from the recurrence rate after open procedures.”
For patients, the stakes of surgery, regardless of approach, are high — 5% to 30% of primary open or arthroscopic procedures for shoulder instability are unsuccessful, according to the Portuguese study.
The technical decisions a shoulder surgeon makes as part of his or her operative plan can have a significant effect on the outcome of the procedure. In the AAOS Now article, Dr. McClelland recommends surgeons to focus on certain technical aspects of arthroscopic shoulder instability repair to enhance the chance of success, including:
- Position of the patient. The beach chair position, in which the patient sits reclined, is familiar to many shoulder surgeons, allows for easy manipulation of the arm and permits a swift transition to open surgery, if necessary, according to Dr. McClelland. However, he writes that this has limitations, including “limited access to the inferior quadrant of the glenohumeral joint and the frequent need for a surgical assistant to provide humeral head distraction,” among others. Those drawbacks are not present in the lateral decubitus position, in which the arm is held in traction perpendicular to the body, but this position carries a higher risk of brachial plexus or peripheral nerve neuropraxia. Dr. McClelland points out a systematic review found that patients who underwent repair in the lateral decubitus position experienced a slightly lower rate of instability after surgery.
- Portal placement. The ability to properly manage sutures and gain access to every area of the shoulder necessary for repair hinge on the surgeon’s choice of arthroscopic portals, according to Dr. McClelland. “A standard Bankart repair is often accomplished through a posterior viewing portal, with a low rotator interval portal for anchor insertion and high rotator interval portal for suture management. When the labral tear extends across the inferior margin of the glenoid, those portals may not allow an appropriate angle for anchor insertion without risk of skiving off the glenoid surface or penetrating the articular cartilage,” he writes. Accessory portals, such as 5 o’clock and 7 o’clock portals, may be necessary to place anchors in certain positions.
- Anchor placement. When placing the first — and most important — anchor on the glenoid, a good rule of thumb is to start as low on the structure as possible, according to Dr. McClelland. He advises placing anchors approximately 1 millimeter onto the glenoid face.
- Anchor number. The optimal number of anchors to use in a Bankart repair is a source of debate. Dr. McClelland stresses that “[t]here must be sufficient points of fixation to securely reapproximate the capsulolabral tissue to the glenoid, create sufficient surface area for reliable healing, support capsular retensioning, and allow for early rehabilitation. The larger the capsulolabral bite, and the more dramatic the capsular shift, the more stress will be placed on each anchor during rehabilitation, and the more points of fixation will be needed.”
- Anchor type. Knotless anchors and those that require tying knots have produced similar results or, in some cases, more favorable outcomes for the former in recent studies, according to Dr. McClelland. He notes that tying secure anchor knots is challenging but imperative for joint stability. He also writes that a study performed on cadavers demonstrated that knotless and knotted procedures showed comparable abilities to restore labral height.