Have you done any quads strengthening exercises? Have you used ice or heat on a regular basis? Post-arthroscopy there will be inflammation, and also swelling in the joint, which is normal for a certain period of time post-op. Even a very small amount of swelling inside the joint (25 cc) can cause pain in the knee and aggravate weakness of the quads. With a long-standing knee problem, there is a reliable body of evidence that targeted, gradual, progressive strengthening of the quadriceps mechanism can give significant improvement. Stationary biking with no resistance, several times a day for short periods to start with will help with range of motion. Strengthening and flexibility exercises should be begun a.s.a.p. after the surgical procedure. I suggest you find a Physiotherapist who specializes in Sports Medecine to guide you through this period.