Articular cartilage injury with acute patellar dislocation in adolescents. Arthroscopic and radiographic correlation.

Acute patellar dislocation and relocation produces major forces at the articular surfaces. Articular injury was assessed in 48 patients, 24 boys and 24 girls (mean age, 14 years), with acute, initial, noncontact patellar dislocations. Correlation of the findings of radiographic and arthroscopic examinations was done. Eleven of the 48 patients (23%) had radiologic diagnoses of articular injuries. Thirty-four of the 48 patients (71%) had arthroscopic evidence of articular damage, 32 osteochondral and 2 chondral injuries. Eight of the 28 (29%) arthroscopically identified osteochondral loose bodies (4 to 20 mm) were identified radiologically. Overall, only 11 of the 34 (32%) arthroscopically documented articular injuries were defined by preoperative radiographs. These standard radiographs provided limited information for management decisions. Poor results after patellar dislocation treatment may involve nonrecognition of articular compromise.