No, leg extension machines do not provide joint compression - use the leg press machine or do body weight squats. I would also advise you try and speak with someone about oesteoarthritis and exercise.

Hope this helps
Dan

hey, don't do ANY exercises that put pressure on the knee apart from straight line exercises for the next 6 weeks, i had minor cartilage damage, took 3 weeks off to repair it then came back to pre season training and ive either tore the crutial ligaments in my knee or tore the cartilage in my knee, both around the shock absorption area so my exercises are limited for a while

hope this helps you,
James