Arthroscopic Glenoid Bone Grafting for Unstable Shoulder Arthroscopy

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FREQUENTLY ASKED QUESTIONS ABOUT GLENOID BONE LOSS & GLENOID BONE GRAFTS 

Question: I HAVE AN UNSTABLE SHOULDER; HOW DO I KNOW IF I NEED AN ADVANCED PROCEDURE LIKE A GLENOID BONE GRAFT?

Answer: Unstable shoulders can be the result of multiple factors, not just a labrum tear.

It is critical to evaluate EVERY patient for the possibility of glenoid bone loss to provide the glenoid bone graftbest possible long term surgical results. For greater detail and review of the subject we recommend an excellent Current Concepts Article about Glenoid Bone Loss published in the Journal of Bone and Joint Surgery. So, if your surgeon has not discussed the possibility of glenoid bone loss and the options available, we highly recommend you consider a second opinion with a shoulder surgeon.

Question: IS THERE AN EASY WAY TO REVIEW MY MAGNETIC RESONANCE IMAGE (MRI) OR COMPUTED AXIAL TOMOGRAPHY (CT) SCAN TO ASSESS FOR GLENOID BONE LOSS?

Answer: In my experience, the MRI and CT scan tend to underestimate the amount of bone loss.

This is especially true in patients with chronic episodes of subluxation rather than MRI of shoulder bone lossrepeated dislocations. The best images to assess for bone loss are the sagittal series, choosing the image that is closest to the joint line itself. Additional articles discussing the significant impact of glenoid bone loss are here: Sports Health and World Journal of Orthopedics.

Question: MOST OF THE ARTICLES AND RESEARCH I CAN FIND MENTION OPEN SURGERY LIKE THE LATARJET PROCEDURE FOR GLENOID BONE LOSS, WHY ARE YOU RECOMMENDING AN ALL ARTHROSCOPIC APPROACH WITH NON-RIGID FIXATION?

Answer: Especially outside the United States, and extensively promoted in Europe for decades, the Latarjet and similar bone block transfer procedures have been utilized to address anterior glenoid bone loss and shoulder instability in general for decades.

Originally developed by Laurent Lafosse and subsequently adopted and promoted by others, the arthroscopic latarjet procedure is an advanced technique that has also gained notoriety over the past decade. Unfortunately, these techniques do have limitations and bone block transfer procedurescomplications. Several articles over the years have evaluated the complications of traditional open and arthroscopic latarjet procedures. Most articles cite complication rates approaching 30%: Laurent Lafosse et al. (Curr Rev Musculoskelet Med. 2015 Mar; 8(1): 59–66); A. Miniaci et al. (J Shoulder Elbow Surg. 2013 Feb;22(2):286-92. doi: 10.1016/j.jse.2012.09.009.); JP Warner et al. (J Bone Joint Surg Am, 2012 Mar 21; 94 (6): 495 -501); BC Vrettos et al. (SA orthop. j. vol.13 n.3 Pretoria Sep. 2014).
These techniques are not anatomic, meaning that they don’t attempt to restore the original anatomy of the shoulder and instead rely on a dynamic sling effect help maintain stability. They are also not helpful for patients with hyper-laxity or shoulder dislocations/instability in more than one direction. So, patients with multidirectional instability and posterior instability that have glenoid bone loss need a different approach. Especially because of the pull of the conjoint tendon exerting a dynamic sling effect and shear force, these techniques have traditionally required rigid fixation (screws or bolts, etc.) that come with their own unique set of complications such as hardware migration, prominence, breakage, etc. Shoulder arthroscopy has many inherent advantages including a significantly lower risk of infection. The publication of an excellent article in 2014 confirming 100% healing rates for glenoid bone grafts for anterior instability using non-rigid fixation really was the light bulb moment that triggered the development of our all arthroscopic technique for glenoid bone graft utilizing non-rigid fixation. The technique avoids the complex dissection and risk involved with the arthroscopic latarjet procedure and avoids the risks associated with rigid fixation methods. Additionally, it is inherently flexible allowing us to apply the bone graft anteriorly, posteriorly, or both to best meet the needs of each patient. Aside from the great benefits realized for the traditional patient with anterior bone loss, patients with posterior glenoid bone loss, hyper-laxity and multidirectional instability also are excellent candidates.

Question: WHY AREN’T THESE TECHNIQUES MORE READILY AVAILABLE?

Answer: Many orthopedic surgeons perform shoulder arthroscopy.

However, advanced techniques like superior capsular reconstruction and arthroscopic glenoid bone grafting require a significantly greater level of training, skill, and experience to master. Here are a few tips on how to find the best doctor for you personally.

Question: WHAT TYPE OF BONE GRAFT DO YOU USE? WHERE DO YOU GET IT? WHAT IS AN ALLOGRAFT?

Answer: An allograft is a graft in which the replacement bone came from another person.

There are several types of allografts: 

We utilize freeze dried bone allografts (rib, fibula, iliac crest, distal tibia, etc.) which the CDC cites as having a more than 30 year history of use without disease transmission for the vast majority of cases. More about bone grafting here.

Question: HOW LONG DOES THE BONE GRAFT TAKE TO HEAL? DOES THIS CHANGE MY REHABILITATION PROTOCOL AFTER SURGERY? WILL THIS DELAY MY RETURN TO SPORTS?

Answer: Healing and incorporation of the bone graft typically requires 6 months.

Generally this is long enough to reach enough strength to allow a return to contact sports and other strenuous activities such as Olympic lifting, etc. This is the same time required for soft tissue repairs such as labrum repairs, so the bone graft does not delay or change the rehabilitation protocol for our patients. Full incorporation and remodeling of bone grafts and all repaired tissues continues for 1-2 years and beyond. On the contrary, many patients have reported an easier postoperative recovery, however, we continue to stress the importance of allowing time for biologic healing and neuromuscular coordination and discourage patients from returning to strenuous activities too soon.

Unstable shoulders are extremely common and successful treatment for shoulder instability can be a complex shoulder instability testmatter. As the most mobile joint in the human body, the shoulder relies on the surrounding tissues for stability and coordinated control of the eighteen muscles that attach to the scapula is vital to maintaining proper balance and function. A lot of work has been dedicated to repair and rehabilitation for various rotator tears and injuries to these soft tissues, but increasingly the bony glenoid deficiency is recognized as a major risk factor for developing an unstable shoulder or shoulder dislocation. The bony glenoid or tee (golf ball on a tee analogy) also provides a solid foundation for attachment of the labrum and capsule contributing to shoulder stability. Whether through injury such as a fracture, gradual erosion via recurrent dislocations and subluxations, a developmental variation resulting in a smaller or altered bony glenoid, or some combination of multiple factors, maximizing the size of the bony glenoid is now recognized as a durable and vital part of the successful long term treatment for unstable shoulders.

Traditionally, in Europe the most favored and successful treatment for anterior instability has been a bone block transfer procedure called the Latarjet Procedure. With advancements in arthroscopic techniques this procedure can now be performed in an arthroscopic fashion by highly experienced and skilled surgeons and the long term results ofmri view shoulder dislocation the Arthroscopic Latarjet Procedure have been encouraging. Limitations of the bone block transfer procedure include the inherent objection that it is not an anatomic procedure, meaning we are not actually reproducing the patient’s original anatomy. Also, as bone loss can occur posteriorly as well the Latarjet procedure is not appropriate for these other areas of potential glenoid bone loss.

The next step forward in addressing glenoid bone deficiency and avoiding the morbidity associated with harvesting the patient’s own bone was the recognition that donated bone heals reliably in this setting and application.

Traditionally, rigid fixation has been used in the form of screws to secure the bone to the glenoid. Several studies have outlined the potential complications associated with the traditional Latarjet procedure and fixation method.

Combining these advancements for restoring the amount of bone at the glenoid utilizing advanced arthroscopic techniques and non-rigid fixation, this study showed 100% graft healing by 12 months after surgery. As the accompanying video demonstrates, patients that have a high level of inherent flexibility are already at increased risk for developing an unstable shoulder and repair of the soft tissues alone can result in recurrent stretching and failure. The other variable I believe may play an important role is the neuromuscular feedback loop for proper control and sequencing of the shoulder girdle. In other words, the rich network of nerves supplying the tissues surrounding the shoulder (labrum, capsule, rotator cuff, etc.) help provide a sense of where the shoulder is in space and also help coordinate the movement of the shoulder girdle for optimum control. In patients with glenoid deficiency, or a smaller glenoid the margin for error of this neuromuscular control system becomes much smaller and the risk for injury proportionally greater. So one of our goals is to try and restore the size of the bony glenoid circle to at least the upper range of normal and if possible even slightly larger in order to give the nervous system a better opportunity to react and provide balanced control of the shoulder girdle and of course restore as much bony support as possible. You can learn more on our resources page.

Author
Vivek Agrawal, MD

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