OsteoArthritis of Knee affects 12.1% of the adult population in the United States [1] . This is a common disease with significant functional impairment, impaired quality of life for the patient and a social cost [1] [2] . It is the second reason for consultation in rheumatology in Saharan Africa and the first location of osteoarthritis in the lower limbs [3] -[8] . Its functional impact is important and appreciated by several scores; the most used ones are the Lequesne score and WOMAC [9] -[11] . Thus, a Lequesne index average of 14.5 or a WOMAC index of 51.3 is an indication for knee arthroplasty [12] .

Existing instruments focus on symptoms and function without taking into account many other aspects of the impact of the disease perceived by the patient including the quality of life and the psyche of the patient. Several scales have been developed and validated. Among these, only the Arthritis Impact Measurement Scales (AIMS2) and short (AIMS2-SF) [13] [14] and the questionnaire OAKHQOL (OsteoArthritis of Knee Hip Quality of Life) allow the understanding of the social components of the disease [15] [16] ; OAKHQOL questionnaire showed that the quality of life of patients with osteoarthritis of the knee or hip was altered in several of its components [17] . Knee osteoarthritis is considered more common in black African woman [18] . However, few studies have been conducted on the quality of life in these patients with OAKHQOL questionnaire. The purpose of this study was to assess the quality of life of patients with knee osteoarthritis in a black African population.

This was a cross-sectional study from January 2013 to June 2013 who concerned all patients received during the study period for symptomatic knee osteoarthritis in Rheumatology consultation at the University Hospital Yalgado Ouedraogo Ouagadougou, Burkina Faso. All patients included in the study met the clinical and radiological criteria of the ACR [19] . They all received a complete clinical examination by the same rheumatologists (ODD and ZTJ). The blood-cell count, erythrocyte sedimentation rate and C reactive protein (CRP) were systematic. Radiography of both knees was performed, incidence face load, schuss, in profile and axial effects at 30 and 60.

Data were collected on a pre-computerized record containing the socio-demographic and anthropometric parame ters, functional signs, physical and radiographic, the algo-functional index (visual analogy scale, Lequesne index) and scale OAKHQOL. The variables were then analyzed using the Epi-info version 7.0. ANOVA and Fisher's exact test were used for statistical analysis. A probability p < 0.05 was considered statistically significant.

This is to our knowledge the first sub-Saharan study of the quality of life with OAKHQOL Questionnaire in patients with knee osteoarthritis. The general characteristics of patients were similar to those of previous studies and other African studies [3] [6] [7] [20] . However, the average age (55 years) of our patients was lower than that of the cohort KHOALA in France (62 years); the body mass index was similar but with an average intensity of the largest pain in our series (55.5/100) than in the cohort KHOALA [21] .

Static disorders of the knees (genu-flessum) and a high score Lequesne seem to be associated with significant impairment of the quality of life of patients. Similarly, it appears that the over 70 years of age has a significant impact on the “social activities” questionnaire OAKHQOL component. The social activity plays an important role in patients of this age group because of their status as resource persons in the African culture.

p^* probabilité.

The normalized values of the different components were higher in our comparison to those of the French series [16] , Spain [22] and Morocco [23] series. The quality of life of patients although reduced, seems better in our series than in those just mentioned. This could be different socio-cultural (greater acceptance of illness) or due to methodological biases. Business data, settings of origin, urban or rural, and living conditions are useful for the interpretation of quality of life scales. The recruitment of our patients was only done in consultation Rheumatology, thus excluding serious surgical consequent having a greater impairment of quality of life. In addition, the psychometric properties and the relevance of the questionnaire OAKHQOL in black African culture are not known. Indeed, we used the French version and it is obvious that some items do not match the black African cultural elements. It is therefore important that we develop a black African version. In addition, OAKHQOL questionnaire is a self-administered [17] . In our study, due to a significant rate of illiteracy, the questionnaire was administered to the patient; this could influence the answers. Further studies are needed with a questionnaire OAKHQOL “tropicalised” and self-administered.

Osteoarthritis of knee has an impact on the quality of life of patients treated in rheumatology consultation in Burkina Faso by OAKHQOL questionnaire. However, this questionnaire should be adapted to the cultural aspects of this part of the world to minimize the methodological biases that may have influenced our results and to understand the real impact of the disease. This would allow a more effective management.

The authors declare no conflict of interest related to this work.