Background KOA and VV are two frequent diseases increasing with age, especially in women. Age, sex, BMI, standing position and heavy works are risk factors of both KOA and VV. The association of the two diseases is variously assessed in the literature: prevalence of VV in KOA patients varies from 18 to 64% and prevalence of KOA in VV patients varies from 12 to 68%. This association is still questionable, as no case-controlled study is available.

Objectives To evaluate the possible association of the two diseases in a case-control study.

Methods Three hundred patients with KOA defined according to the ACR criteria (mean age ± SD: 66 years ± 10, 64% women) were age and sex-matched with 300 controls (subjects without any present or past knee pain + normal examination of their knees + normal AP x-rays of their knees on standing extended position: Kellgren-Lawrence stage 0). All classical risk factors were recorded (sports, trauma, heredity, works, meniscectomy, ?). In this epidemiological survey, VV were classified as followed: no VV (V0), simple venous varicosities with dull ache or pressure sensation in the legs which feel heavy after prolonged standing, (V1), or VV with complications (erythema, dermatitis, hyperpigmentation developed along the distal aspect of the leg, or skin ulcers) or which were operated (V2). This grading system was set up assuming that the diagnosis of VV at stage 1 is sometimes questionable, while VV at stage 2 is more accurate.

Results There were 95 and 74 V1 patients and 59 and 43 V2 patients in KOA and control groups respectively (Chi2 = 9.28; p = 0.0097). This increase of VV in KOA is also significant in women (chi2 = 9.498; p = 0.0087), but not in men (p = 0.34). As age, body mass index, hypertension, smoking, sports, carrying heavy loads are confounders in both diseases, a multiple logistic regression was performed. There was a relationship between VV and carrying heavy loads, leading to two separated analyses.

Conclusion When there is no carrying of heavy loads, the RR of KOA is not significantly increased with the presence of VV, while it is when heavy load carriage is also present.