Synovial shelves of the knee: association with chondral lesions

The objectives of the present study were to evaluate whether synovial shelves of the knee are associated with increased incidence of chondral lesions and to determine which types of plica are associated with significant articular damage. Data were collected prospectively from 1,000 consecutive knee arthroscopies. Of these patients, 321 (32.1%) were found to have synovial shelves of the knee. Patients details (age, sex, duration of symptoms, injuries, and possible mechanism of injury), operative details (types and number of portals, equipment used), intra-articular findings (articular, meniscal and synovial lesions, and stability characteristics) and procedures performed were recorded on a special database. Synovial shelves of the knee were recorded using a modification of the Sakakibara classification. Articular lesions were noted on anatomic articular maps of the different functional zones using a functional zoning system that presaged the current ICRS system. An increased incidence of articular lesions was found in patients with synovial shelves, in comparison with patients without shelves (94.7 vs. 81% respectively; P < 0.001). Patients with larger and more fibrotic shelves were found to have increased incidence of cartilage lesions, in comparison with patients with type smaller and less fibrotic shelves (96.5 vs. 86.4%, respectively; P = 0.002), as well as cartilage lesions with bigger size (84 vs. 71.4%, respectively; P = 0.02). Patella (P < 0.001), and specific areas (P < 0.001) of the medial femoral condyle, were areas with increased incidence of cartilage lesions, in patients with synovial shelves. In conclusion, synovial shelves of the knee are associated with an increased incidence of cartilage lesions. Larger shelves, particularly with chronic inflammation are associated with more frequently occurring and larger articular lesions. Areas with increased incidence of chondral lesions, in patients with plicae, include particularly the lower patella and the non-weight-bearing medial femoral condyle.