Shoulder Surgery Complications: An Ounce of Prevention

Predicting the Likelihood of Shoulder Surgery Complications

Shoulder surgery complications occur all too commonly. The choices we make as patients both before and after surgery can play a significant role in predicting the likelihood of a complication after shoulder surgery. A common saying in shoulder surgery is, “The surgeon is the method,” meaning that any innovative technique, tool, or procedure is really only as good as the person using it. While this makes intuitive sense to us when we think about other fields of endeavor, it is harder to remember when faced with the prospect of finding a solution to persistent shoulder pain and debility. More information on how to go about the decision making process of finding the best shoulder surgeon for your personally is available at our pages shoulder specialist and shoulder pain.

Implants Related to Shoulder Replacement

The choices we make as patients after surgery can also play a major role in predicting a shoulder surgery complication and we plan a more in depth review of this topic in an upcoming article. Please watch the video below:

Click here to watch a video about Shoulder Surgery Complications.

A more subtle and sometimes difficult to evaluate factor in predicting shoulder surgery complications is the choice of technique or implant by the surgeon. While this is true for implants related to shoulder replacement and other reconstruction procedures as well, we focus presently on the ever-expanding area of tissue repair in shoulder surgery. Shoulder tissue (capsuleligamentslabrumcartilagerotator cuff, etc.) can become stiff, stretched, or completely torn and with the emergence of technology and more minimally invasive techniques, the methods to mend these tissues have also evolved.

Shoulder Tissue Repair Techniques

When many of the shoulder tissue repair techniques and implants were originally conceived, the goal was to reproduce the same methods the surgeon would perform in a fully open surgery, meaning using needle and thread to mend the tear, or if the tissue needed to be repaired back to bone, the thread (suture) would be passed through bone tunnels and then tied.  With the recognition that the quality of the bone varies significantly in different areas of the shoulder as well as among different patients due to multiple factors and the risk to surrounding nerves and vessels with certain suture passing techniques recognized, a leap forward was the invention of the suture anchor, designed to provide a way to mend the tissue back to bone in a more reliable, safe and strong fashion.  These suture anchors were originally made of metal with the suture threaded through them.  As we gained more experience with these devices and the techniques evolved, it became clearer that despite the use of reliable and reproducible delivery systems, technical difficulties and complications with these devices did occur.

Shoulder Revision Surgery

Shoulder surgery complications reported with these devices include: incorrect placement, migration after placement, loosening, breakage, and tissue damage from the implant being significantly harder than the surrounding tissue. Catastrophic grinding down of joint cartilage is a potentially devastating complication from a prominent or displaced metal anchor. Because the metal can often interfere with further imaging studies, it can also be difficult to fully assess the quality of the tissue healing with metal anchors. Particularly for shoulder dislocation or unstable shoulder, in the event of the patient requiring a repeat or revision surgery, the amount of bone real estate available for mending the tissue back to bone can be severely limited and the need to remove the prior anchor and graft the bone void may arise, potentially meaning the patient may have to have yet another surgery once the bone void heals.

Critical Shoulder Healing Phase

In response to these concerns, the next generation of devices to mend tissue back to bone included suture anchors and tacks made of non-metallic and absorbable polymers. The hope and idea behind the absorbable polymers was that they would provide the needed stability during the critical healing phase of the tissue back to bone and then the body will gradually dissolve or resorb these away, hopefully, leaving no trace behind. While in the vast majority of cases these implants have been used with great facility and success, there have been problems in a handful of reported cases. Initial implants made with polymers such as polyglycolic acid and polyglycolic acid-trimethylene carbonate copolymer had problems with draining sinuses and lytic bony change (meaning the bone dissolved around them). This led to poly-L-lactic acid (PLLA) becoming the polymer of choice for most absorbable or degradable implants because it degraded much more slowly (up to 5 years). Over time this has been further refined to include different recipes to achieve a more favorable biologic reaction, including the admixture more recently of calcium compounds to promote bony replacement/ingrowth of these implants.

Local Implant Stresses

Based on multiple factors including the local stresses placed on the implant, the number of implants, design of the implant, and rate of degradation, one portion of the implant can conceivably resorb or break more easily leaving some portion as a loose or free body in the shoulder joint. These can lead to shoulder surgery complications, as well as inflammation, joint damage, grinding, and failure of the repair.

Improved imaging characteristics, potentially fewer problems with revision surgery, and eventual resorption are advantages biodegradable anchors have over metal anchors. Because of their strength and reduced risk of inflammatory response and osteolysis, metal anchors also continue to command a prominent role in shoulder repair.

Variables of Bone Loss

Particularly for shoulder dislocation, labrum tear, and unstable shoulder surgery, bone loss and the amount of bone available are significant variables to consider. The next generation of anchors for tissue repair to bone has taken a novel approach to fixation using 100% suture for fixation. Recognizing the inherent limitations of both metal and absorbable anchors in this challenging application, these purely suture anchor devices offer the advantage of avoiding the risks of osteolysis and inflammatory resorption response, while also greatly reducing the risk of subsequent fracture propagation because the anchor is tiny (1.4mm) -creating a tunnel that is nearly two-thirds smaller than other available anchors. Another advantage we have already seen in patients that have suffered an unfortunate injury after shoulder surgery with these implants is that revision surgery is significantly easier for the patient and surgeon.

Shoulder Repair Summary

Regardless of the type of fixation device used, surgeons and patients should be aware of the type of implant used for their operation and that any unexpected event that occurs after a shoulder repair surgery may result in compromise of the repair with a broken suture or implant. If you experience an unexpected event and start to have grinding, squeaking, or other catching type symptom, keep this possibility in mind and discuss it with your shoulder surgeon. Knowledge of the mechanisms of failure, recognizing the possibility and vigilance are “an ounce of prevention” to avoid more serious shoulder surgery complications.

Author
Vivek Agrawal, MD

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