Background: Lysholm Knee Scale is a knee- is an instrument used to assess the results of rehabilitation from knee injuries, especially those requiring anterior cruciate ligament reconstruction. it measures recovery of knee joint function based on activities of daily living. Objective :The purpose of this study will be to test the face validity, the content validity, the feasibility, the internal consistency reliability and the test retest reliability of Arabic-language version of Lysholm knee scale to measure the PF level in knee osteoarthritic patients. Methods: Two expert panels (first panel consists of eight experts and second panel consist of seven experts) and 40 patients with knee OA participated in this study, 80 sheets (including retest sheets) were filled out in this study considering that bilateral knee osteoarthritic patient. Forward translation, development of preliminary initially translated version, backward translation, and development of the pre-final version and testing of pre-final version using experts then testing of the final version on patients was done. Clarity index, expert proportion of clearance, index of content validity, expert proportion of relevance, descriptive statistics, missed item index, time taken to answer the scale, Cronbach’s coefficient alpha and Spearman’s rank correlation coefficients were used for statistical analysis. Results: The study showed thatThe Arabic version of Lysholm Knee Scoring Scale has excellent face validity as scale index of clarity equaled 93.88%, and the mean of proportion of clearance (clear responses) equaled 93%, also it has excellent content validity as S-CVI equaled 89.12%, and the mean of the proportion of relevance (relevant responses) equaled 88.6%.The scale items were filled out by 99.4% in all sheets and it needed three minutes or less to be answered in about 57.7% of all and also it needed less than 5 minutes in about 82.7% sheets , cronbach's alpha equaled .853 and spearman's rank correlation coefficients between test &retest were statistically significant (item1:0.944,item 2:0.976,item 3:0,924,item 4 :0,989,item 5 :0,838,item 6: 0.951 , item 7:0.896,item 8:0,969). Conclusion: Arabic-language version of lysholm knee scale has face and content validity, feasibility and internal consistency and test retest reliability enough to measure the physical function in knee osteoarthritis patients.
