Baker's Cyst with Knee Osteoarthritis: Clinical and Therapeutic Implications

Several symptoms are common to knee osteoarthritis and Baker's cyst. To what extent each condition contributes to the patient's discomfort is still a matter of debate. The aim of the present study was twofold: first, to compare the burden of symptoms in patients with isolated knee osteoarthritis and patients with knee osteoarthritis associated with Baker's cyst; second, to assess the outcomes after conservative treatments.

Patients suffering from monolateral idiopathic knee osteoarthritis were enrolled. Demographic, anthropometric and clinical data (KOOS scale) were collected. Ultrasound evaluation was performed according to standard protocols. On the basis of the clinical presentation different therapeutic options were used (fluid withdrawal, hyaluronic acid and/or steroids injections).

One-hundred and thirty patients were included in the study (97 with isolated knee osteoarthritis, 33 with knee osteoarthritis and Baker's cyst). In basal conditions, lower scores in KOOS sub-scales were observed in patients with knee osteoarthritis associated with Baker's cyst and in patients with effusion compared with patients without effusion. At 3 months after therapy significant higher scores were observed in both groups. At 6 months the scores were unchanged in the patients without Baker's cyst, but worsened in those with Baker's cyst.

The study shows that Baker's cysts associated with knee osteoarthritis contribute to the burden of symptoms. The conservative treatment of both conditions allows significant improvements, but in the medium term (6 months) the efficacy of the therapy declines in patients with knee osteoarthritis associated with Baker's cyst.