What do badminton players, basketball players, weight lifters, long-distance runners, and hockey players all have in common? Any of them can develop a condition called medial tibial stress syndrome (MTSS). With MTSS, there is pain in the lower leg that gets worse with exercise. This condition can occur in one or both legs. The bone affected is the tibia, the larger of two bones in the lower leg.

No one knows for sure what causes this problem. It could come from inflammation or a tiny fracture. With continued advances in medical technology, researchers hope to find the cause of MTSS. Two breakthroughs in testing bones are bone scans and bone density tests. A bone scan involves a special camera and radioactive substance that show "hot spots" in the skeleton due to over-activity of bone cells. Bone density tests are a special type of X-ray that measures mass within bones. When researchers applied these imaging methods to the tibia, they made some interesting discoveries.

Athletes with medial tibial stress syndrome were compared to two other groups. The first group included athletes of the same sex and age who did not have MTSS. The second group had volunteers of the same age and sex who were not athletes but exercised at least two hours a week.

There were three important findings: (1) athletes with MTSS had lower bone density in the problem area, (2) bone density was decreased in both tibia bones even when symptoms were only present on one side, and (3) athletes with MTSS had higher bone density overall than the nonathletes, but not as high as athletes who did not have MTSS.

Which came first--the tibial stress syndrome or the decreased bone density? For now, researchers can only guess. Loss of bone density may occur as a result of exercise or from a problem with bone development in the growth years. Exercise may simply trigger a reaction to a problem that's already there.

Researchers hope that, by studying athletes with low bone density in the lower leg (but no symptoms), the cause of MTSS will be found. Bone scans and bone density tests may help researchers see how changes develop and whether bone density improves when symptoms disappear.

Reference:

Håkan I. Magnusson, MD, et al. Abnormally Decreased Regional Bone Density in Athletes With Medial Tibial Stress Syndrome. In The American Journal of Sports Medicine. November/December 2001. Vol. 29. No. 6. Pp. 712-715.'