Q: I have arthritis in one ankle from a bad break I got when I was a wild and wooley 20-something. Now I'm paying for it in my 40s. Is there any way to tell if I'm getting worse over time and when I should have surgery? I want to put it off for as long as possible.

A: Severe ankle arthritis is less common than hip or knee arthritis but just as disabling. It is possible to take baseline measurements and to measure the impact of ankle arthritis on function. Limitations in function during daily activities is referred to as impairment of function.

There are several different ways to assess function including counting the number of steps taken each day, step length, walking speed, and ankle motion. These measurements can be compared to normal, healthy adults of the same age and sex (male or female) who did not have any ankle problems or to your other ankle if it isn't damaged. It might be better to use adult controls instead of your unaffected ankle because if your walking (gait) pattern is affected on one side, it's likely there will be compensations on the other side even if it is normal and without injury.

Choosing between ankle fusion (called arthrodesis) and ankle replacement (arthroplasty) is always a challenge. Fusion limits pain because it stops ankle motion. But loss of ankle and foot motion causes changes or alterations in the walking (gait) pattern. That in itself can cause further problems later on. Ankle replacement restores ankle motion and takes the pressure and load off the other nearby joints. But long-term studies of ankle replacement are not showing outstanding results at this time.

The question then becomes: is function affected by end-stage ankle arthritis? If so, how can we measure the amount of disability? At what point do the results of these tests suggest surgery is the best treatment? And finally, which type of surgery is best: fusion or replacement?

Not all of these questions have been answered yet. But researchers have at least gotten a start on evaluating which tests and measures provide the most information about function and activity limitations. And they are beginning to see how the effects of end-stage ankle arthritis impact health and quality of life for these patients.

Average walking speed, number of steps taken each day, and length of steps can be correlated with physical function. These tests can help identify problems with ankle motion and function. It is likely that these same measures could be used in future studies. They can be used to determine when treatment should begin and what type should be provided.

Right now, that information isn't available to help you make your decision. Your surgeon will be the best one to advise you about the use of conservative (nonoperative) care. He or she will also guide you as to when to consider surgery and what type of surgery is best for you.

Reference: Ava D. Segal, MS, et al. Functional Limitations Associated with End-Stage Ankle Arthritis. In The Journal of Bone and Joint Surgery. May 2, 2012. Vol. 94. No. 9. Pp. 777-783.