Nearly half of patients with first-time patellar dislocation underwent operative treatment
COLORADO SPRINGS, Colo. — Nearly half of patients with a first-time patellar dislocation and most patients with recurrent patellar dislocations underwent operative management, according to results presented here.
To better describe clinical characteristics and predictors of clinical outcomes in young patients with patellar instability, Meghan E. Bishop, MD, and colleagues enrolled patients 10 to 35 years of age who experienced a patellar instability event into the Justifying Patellar Instability Treatment by Early Results (JUPITER) study. Researchers confirmed patellar dislocation using radiographs, MRI and clinical assessments, and collected baseline information, including patient demographics, dislocation history, physical exam characteristics and baseline validated patient-reported outcome scores. Researchers categorized patients into groups based on whether they experienced a first-time dislocation or a recurrent dislocation, as well as whether they underwent nonoperative or operative treatment for comparison.
Among the 1,825 patients enrolled in the study, 63% reported more than one dislocation, with 73% of patients undergoing operative treatment and 27% of patients undergoing nonoperative treatment. Bishop noted 87% of patients with recurrent dislocations and 47% of patients with first-time dislocations underwent operative treatment.
“Concerning the mechanism of injury for first dislocation, the majority of patients had non-contact [injuries], with 68% reporting a non-contact injury,” Bishop said in her presentation at the American Orthopaedic Society for Sports Medicine Annual Meeting. “There was no difference between the first-time or recurrent dislocators concerning this, and 29% of patients required manual reduction on first dislocation.”
Patients in the recurrent group and the operative group had a significantly more positive J-sign, apprehension and crepitus in the involved knee, as well as a significantly more positive J-sign and apprehension in the contralateral knee, according to Bishop. She also noted patients in the recurrent group were nearly twice as likely to be ligamentously lax compared with patients with a first-time dislocation.
“Concerning patient-reported outcome scores, these did vary, but we found from recurrent dislocators, they generally had lower sporting-related activity scores, and recurrent patients generally had higher activities of daily living scores compared to the first-time dislocations, suggesting a potential compensatory adaptation mechanism with time,” Bishop said.
Perspective
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This study by Meghan E. Bishop, MD, and colleagues represents the initial data from the JUPITER cohort. JUPITER is another example of a high-quality, multicenter, prospective cohort study of a relatively large group of patients designed to help us evaluate and treat a specific injury, in this case, patellar instability. Although I did not have the opportunity to read a full manuscript, I was present for the AOSSM presentation and have reviewed the abstract.
In their cohort of 1,722 knees, 59% were identified as recurrent dislocators, 89.7% of whom underwent surgical treatment. Of the first-time dislocators, operative treatment was indicated in 42.9%, half of whom presented with an osteochondral fracture. Knees with recurrent instability had a higher percentage of positive physical findings including J-sign, ligamentous laxity and patellar apprehension. One interesting finding was that although recurrent dislocators reported lower levels of activity, they also had less deficits on function scores related to daily activities, suggesting compensatory behavior.
I applaud the 21 surgeons at the 12 institutions who make up the JUPITER group and look forward to the prospect of future follow-up studies which will provide data to help us take better care of our patients.
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Bishop ME, et al. Paper 49. Presented at: American Orthopaedic Society for Sports Medicine Annual Meeting; July 13-17, 2022; Colorado Springs, Colo.
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