Assessment of cystic lesions around the knee with MRI and their relationship with osteoarthritis

Abstract

Aim: The large number and different varieties of cysts and cyst-like lesions around the knee joints are commonly encountered on the magnetic resonance scanning. We aimed to evaluate type, frequency, and size of cystic lesions observed around the knee joints and to find out its relationship with osteoarthritis. Material and Methods: 620 knee joints belonging to 545 patients were enrolled in the study. We retrospectively examined magnetic resonance images of the knee joints which were divided into three groups as non-degenerative, mild degenerative, and severe degenerative. The cysts have been classified according to count, type and size and their relationship with knee osteoarthritis was assessed. Results: Out of 620 knees, 248 knees (40%) had no degenerative arthritis, 178 knees (28.7 %) had mild, and 194 knees had severe (31.3 %) degenerative arthritis. Cystic lesions were identified in 411 knees (66.3%). One cyst in 261 knees, two cysts in 102 knees, three cysts in 40 knees, and four cysts in 8 knees were encountered. Increased number and average diameter of the cysts showed statistically significant relation with the degree of osteoarthritis (p<0.001 and p=0.04, respectively). Moreover, some types of cysts such as synovial cysts, intraarticular ganglion cysts, and intraosseous cysts were significantly increased with osteoarthritis (p<0.001). Conclusion: There was significant increase in frequency, number, and average size of knee joint cysts in patients with degenerative arthritis findings. In addition, almost all cyst types except intrameniscal and parameniscal cysts, were found more frequently in the knees with degenerative arthritis.