Distance to dislocation may be indicator of recurrent instability following Latarjet
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Key takeaways:
- Distance to dislocation may be a stronger prognostic indicator of recurrent instability than glenoid bone loss.
- Future studies are needed to identify contributors to return to sport.
WASHINGTON — Results presented here showed that distance-to-dislocation may be a stronger prognostic indicator of recurrent instability than glenoid bone loss following Latarjet.
In a retrospective analysis, Albert Lin, MD, and colleagues identified 75 consecutive patients who underwent primary open Latarjet reconstruction to determine whether distance to dislocation was a predictor of recurrent dislocation and return to sport following open Latarjet. After excluding patients who had connective tissue disorder, seizure disorder or insufficient follow-up, the final cohort included 52 patients (mean age, 23 years). The average follow-up was 5 years, with a minimum 2-year follow-up.
“Our primary outcome was postoperative failure, which we defined as recurrent instability, either recurrent dislocation or subjective instability,” Lin said in his presentation at the American Orthopaedic Society for Sports Medicine Annual Meeting. “The secondary outcome was return to sport within 1 year after the index operation.”
Researchers found that 7% of patients experienced recurrent instability, with about 9.6% experiencing recurring subjective instability. In addition, Lin said that there was about an 80% to 90% survival rate after 5-year follow-up.
Multivariate analysis showed that lower distance-to-dislocation values, or more off-track lesions, were associated with higher rates of recurrent instability, according to Lin. Additionally, Lin noted that after adjusting for percentage glenoid bone loss, every millimeter increase in distance to dislocation was associated with about a 30% decrease in recurrent instability rate. However, researchers found that distance to dislocation was not predictive of return to sport.
“This suggests that the amount of glenoid track correction with the Latarjet may influence outcomes and persistent off-track or near-track lesions may require a different approach,” Lin said. “We believe the findings of this study may influence decision-making and the patient selection criteria for a Latarjet.”
Perspective
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This study by Albert Lin, MD, a true thought leader in scientific research of anterior shoulder instability, is an important contribution to our understanding of the difficulties in treating the unstable shoulder.
Of note in this series, the tried-and-true Latarjet procedure resulted in a nearly 10% failure rate. Lin implements the ingenious “distance to dislocation” as a measure of how far “on track” Hill-Sachs lesions were to becoming “off track.” In other words, the farther the edge of the Hill-Sachs lesion is located away (lateral) to the track, the better patients fared with Latarjet alone.
The glenoid track concept must be embraced as a continuum as “near-track” humeral head defects (Hill-Sachs lesions within approximately 8 mm of engagement) portend a far worse prognosis.
Thus, when faced with a smaller distance to dislocation – less than 8 mm – it behooves the surgeon to maximize glenoid width or address the Hill-Sachs lesion.
The distance to dislocation can be maximized by adding a large glenoid bone graft, which medializes the glenoid track and places it more removed from engagement. Practically speaking, the Hill-Sachs lesion can be addressed with remplissage, which not only fills the lesion, but pulls the humeral head posteriorly and thereby lessens “engagement.”
Many coracoid processes do not contain adequate size to fulfill the task of supplying enough glenoid width. Innovative imaging techniques can help us determine coracoid dimensions preoperatively. In addition, the performance of remplissage immediately before Latarjet may be necessary when a ”near- track” lesion may result when coracoid transfer alone is performed.
Bottom line, if preoperative distance to dislocation is less than 8 mm to 10 mm, Latarjet alone may not suffice, especially if preoperative workup reveals a smaller coracoid process. Consider using the “big guns” if necessary – large distal tibia allograft, Eden-Hybinette and add remplissage.
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Lin A, et al. Paper 1. Presented at: American Orthopaedic Society for Sports Medicine Annual Meeting; July 12-16, 2023; Washington, D.C.
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