Association between medial meniscus extrusion under weight-bearing conditions and pain in early-stage knee osteoarthritis

Purpose This study aimed to investigate the association between the severity of medial meniscus extrusion (MME) under weight bearing and pain in patients with early-stage knee osteoarthritis (OA). Methods Twenty-eight patients with symptomatic early-stage knee OA (Kellgren and Lawrence grade <= 2) who visited our outpatient clinic between 2016 and 2018 were included in this cross-sectional study (mean age: 58.0 +/- 11.6 years, female: n = 10). MME was evaluated under weight-bearing conditions using ultrasonography. Patients were divided into two groups according to the severity of MME under weight bearing: those with MME >= 3 mm were assigned to the severe group, whereas those with MME < 3 mm were assigned to the mild group. The knee injury osteoarthritis outcome score (KOOS) system was used to evaluate knee pain. The incidence of bone marrow lesions (BMLs) was evaluated using magnetic resonance images. Results The KOOS pain score was significantly lower in the severe group than in the mild group (P < 0.05). The incidence of BMLs was significantly higher in the severe group (69%) than in the mild group (7%) (P < 0.001). Conclusion Patients with early-stage knee OA who have greater MME under weight-bearing have more intense knee pain and a higher incidence of BMLs.

Automated summary

Patients with early-stage knee osteoarthritis who have greater medial meniscus extrusion under weight-bearing experience more intense knee pain and a higher incidence of bone marrow lesions.