Q: I had a meniscus that was repaired arthroscopically five years ago. I'm just checking to see how long they think this repair job will last me. Different studies report success rates that vary from 70 to 90 per cent. How do they tell whether the meniscus is holding up or not?

A: There are three ways to measure long-term success or results from meniscal repairs. First is the patient's own report. Is the knee stiff or painful? Can you move the knee joint through its full motions?

Are there any activities (e.g., squatting, climbing stairs, running) that are limited by your knee? Do you have full strength on that side? And how is your standing balance on that side compared with the uninjured side?

Second, the surgeon looks at imaging studies such as X-rays, MRIs, and arthrograms to see the size and shape of the joint space (distance between the two bones that make up the knee joint).

Any narrowing (especially on the side of the injury) of the joint space may be a warning flag of future joint degeneration leading to arthritis. These imaging studies also provide an idea of the condition of the surrounding soft tissues.

And the most reliable test of all: a repeat arthroscopic examination. Taking a look inside the knee joint using a special instrument called an arthroscope is referred to as a second-look arthroscopy.

Surgeons don't routinely perform second-look arthroscopic examinations. They are invasive and costly compared to the other types of evaluation. But when formal studies are done, this kind of follow-up is really necessary to get examine the full extent of healing and recovery.

Reference: K. Donald Shelbourne, MD, et al. Long-term Evaluation of Posterior Lateral Meniscus Root Tears Left In Situ at the Time of Anterior Cruciate Ligament Reconstruction. In The American Journal of Sports Medicine. July 2011. Vol. 39. No. 7. Pp. 1439-1443.