Is there an association between chronicity of patellar instability and patellofemoral cartilage lesions? An arthroscopic assessment of chondral injury.

The purpose of this study was to investigate the association between chronicity of patellar instability on the prevalence, grade, and location of chondral lesions in patients with recurrent patellar instability. Patellofemoral chondral status was documented and graded according to the Outerbridge classification in 38 patients who underwent arthroscopic examination at the time of a medial patellofemoral ligament reconstruction procedure. Chondral lesions of any location were observed in 63.2% of patients. Patellar and trochlear lesions were observed in 57.9 and 13.2% of patients, respectively. There was a significantly higher duration of patellar instability in patients with a trochlear lesion versus those without a trochlear lesion (p < 0.01), and in patients with combined patellar and trochlear lesions versus those without both patellar and trochlear lesions (p < 0.01). There was a significant correlation between chronicity of patellar instability and Outerbridge grade of trochlear chondral injury (p = 0.01). Chi-squared analysis revealed that chronicity of patellar instability greater than 5 years was significantly associated with the likelihood of trochlear lesions (p < 0.05). We conclude that patients with increasing chronicity of patellar instability may have a higher likelihood of and higher grade of patellofemoral chondral injuries, specifically for trochlear lesions.