To determine (i) clinicoradiological presentation and outcome of rapidly destructive knee osteoarthritis (RDKOA) after global medical treatment including knee lavage plus corticosteroid injection, (ii) predisposing factors of subsequent requirement to knee surgery.

Retrolective monocenter study with tibiofemoral RDKOA, defined as a loss of at least 50% of joint space width within 1 year, with a post lavage follow-up of at least 1 year.

One hundred and eleven patients were enrolled, age 64.1 years, BMI: 28.9, 70.3% female. VAS pain was 56.1mm, Lequesne index: 11.9, WOMAC function score: 51.9. Chronic mechanical effusion (216 white cells/mm³) was aspirated in 102 patients (91.9%), lasting more than 6 months in 71.4%. Medial tibiofemoral compartment was concerned in 79.3%. Joint space loss reached 52.2% in extension and 71.0% in semi-flexed position within a mean 7.3-month period. Radiological chondrocalcinosis was present in 13.5% and osteonecrosis in 12.6%. Lavage (one liter, two 14-gauge cannulae) plus corticosteroid was completed by hyaluronic acid injections in 71.2% of patients. Eighty-nine patients were reviewed with a mean follow-up period of 55.0 months. Thirty-seven (41.6%) required surgery. Mean delay between lavage and surgery was 16.1 months. Pain was acceptable in 100.0% of operated patients and 87.8% of non-operated patients. Multivariate regression analysis determined that functional impairment, assessed by the maximal walking time, and radiological severity in extension were baseline predisposing factors of subsequent requirement to surgery.

The outcome of RDKOA seems less severe than expected after global medical treatment.