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.
Meghan E. Bishop
“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.