Multiple shoulder dislocations increased risk of bone loss
More than one shoulder dislocation prior to anterior stabilization surgery significantly predicted bone loss among athletes, according to results.
Carolyn M. Hettrich, MD, MPH, and colleagues performed a proportional odds model for 895 patients who underwent either arthroscopic or open primary anterior stabilization surgery of the shoulder to determine the predictors of any glenoid bone loss, anterior glenoid bone loss greater than 10%, any posterior humeral head bone loss, posterior humeral head bone loss greater than 10% and combined lesions.
“Bone loss was determined by surgeons based on intraoperative measurements and preoperative imaging,” Hettrich said in her presentation at the Arthroscopy Association of North America and American Orthopaedic Society for Sports Medicine Specialty Day.
Hettrich noted 20% of patients had a bony Bankart lesion, 53% had a Hill-Sachs lesion and 19% of patients had combined lesions. She added 75% of patients experienced more than one dislocation.
“Predictors of having any glenoid bone loss included increasing age, male sex, non-white race, contact sport participation and for each additional dislocation, there was an 81% increase of having bone loss,” Hettrich said.
Predictors of having glenoid bone loss greater than 10% showed lower activity levels were protective while increasing number of instability events were strongly predictive, according to Hettrich. She noted athletes who experienced a second instability event would be 257% more likely to have bone loss compared with athletes who had a single instability event.
“Changing gears to look at predictors of posterior humeral bone loss or Hill-Sachs lesions, risk factors for the presence of any Hill-Sachs lesion included male sex, non-white race, presence of anterior apprehension preoperatively and, again, increasing number of dislocation,” Hettrich said.
Hettrich noted increasing age and increasing number of instability events were predictive of increased posterior humeral head bone loss greater than 10%.
“Lastly, to look at our fifth model, combined anterior glenoid and posterior humeral bone loss, risk factors, again, included increasing age, non-white race and increasing number of instability events with nearly double the likelihood with subsequent dislocation,” Hettrich said.
Perspective
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In this study of 895 patients who underwent primary anterior stabilization by 26 different surgeons for shoulder instability, the key take-home message is an increasing number of preoperative dislocations is a significant predictor and modifiable risk factor for bone loss.
Increasing bone loss is associated with increased failure of surgery, especially arthroscopic stabilization surgery, which is performed in more than 90% of cases in the United States. The authors suggest this data supports earlier surgical intervention in this active population should be strongly considered, using the analogy of ACL rupture and the current recommendation of early intervention and reconstruction not only to stabilize the knee joint, but also to prevent further damage to the knee joint.
Looking more closely, a remarkable finding that deserves attention is the patient population that was non-white (16.5%) had statistically significantly elevated risk of any anterior bone loss, any posterior humeral bone loss and combined bone loss. However, this difference was not present when setting the criteria of more than 10% anterior or more than 10% posterior humeral bone loss. The authors also looked at sex as a possible factor (20.9% of the population was female), and essentially found the same results demonstrated with race.
Less than 10% of all peer-reviewed orthopedic papers look at these factors when assessing outcome, despite the fact there are multiple conditions that have unique differences in outcome (eg, osteonecrosis of bone, ACL reconstruction) and recommendations for treatment. While these factors are not modifiable, these provide additional information that may help improve our ability to provide more precise recommendations and care for our patients.
While racial disparities related to common orthopedic procedures continue to show increasing inequality, which requires a reassessment of the entire health care delivery system, the findings of this study should encourage careful assessment, including advanced imaging studies, to accurately determine bone loss with anterior shoulder instability in all patients who present to our office, without bias related to race or gender.
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Hettrich CM, et al. Paper 1. Presented at: Arthroscopy Association of North America and American Orthopaedic Society for Sports Medicine Specialty Day; March 17 and 18, 2021 (virtual meeting).
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