Knee Injury and Cortisone

Corticosteroids, such as cortisone and Prednisone, have an adverse effect on bone and soft tissue healing. Corticosteroids inactivate vitamin D, limiting calcium absorption by the gastrointestinal tract, and increasing the urinary excretion of calcium. Bone also shows a decrease in calcium uptake with cortisone use, ultimately leading to weakness at the fibro-osseous junction. Corticosteroids also inhibit the release of Growth Hormone, which further decreases soft tissue and bone repair. Ultimately, corticosteroids lead to a decrease in bone, ligament, and tendon strength.

Corticosteroids inhibit the synthesis of proteins, collagen, and proteoglycans in articular cartilage, by inhibiting chondrocyte production, the cells that comprise and produce the articular cartilage. The net catabolic effect (weakening) of corticosteroids is inhibition of fibroblast production of collagen, ground substance, and angiogenesis (new blood vessel formation). The result is weakened synovial joints, supporting structures, articular cartilage, ligaments, and tendons. This weakness increases the pain and the increased pain leads to more steroid injections. Cortisone injections should play almost no role in sports injury care. Although anti-inflammatory medications and steroid injections reduce pain, they do so at the cost of destroying tissue. In a study conducted by Siraya Chunekamrai, D.V.M., Ph.D., steroid shots, of a substance commonly used in humans, were given to horses. The injected tissue was looked at under the microscope. The steroid shots induced a tremendous amount of damage, including chondrocyte necrosis (cartilage cell damage), hypocellularity (decreased number of cells) in the joint, decreased proteoglycan content and synthesis, and decreased collagen synthesis in the joint. All of these effects were permanent.

Dr. Chunekamrai concluded, “...the effects on cartilage of intra-articular injections of methylprednisolone acetate (steroid) were not ameliorated at eight weeks after eight weekly injections, or 16 weeks after a single injection. Cartilage remained biochemically and metabolically impaired.” (Chunekamrai S. Changes in articular cartilage after intra-articular injections of methylprednisolone acetate in horses. American Journal of Veterinary Research 1989;50:1733-1741)

In this study, some of the joints were injected only one time. Even after one steroid injection, cartilage remained biochemically and metabolically impaired. Other studies have confirmed similar harmful effects of steroids on joint and cartilage tissue. A cortisone shot can permanently damage joints.

The problem with athletes is that they look for quick relief. The problem with cortisone is that the athlete may get pain relief, but it may be at the expense of permanent inability to participate in athletics. Athletes often receive cortisone shots in order to play. They go onto the playing field with an injury of such significant magnitude that they received a cortisone shot to relieve the pain. Unfortunately, they cannot feel the pain anymore so they play as if there was no injury. We know that the injury could not possibly be healed because of the tremendous anti-healing properties of cortisone. Thus the athlete is further injured from the cortisone, as well as playing with an injury, thereby worsening the already bad injury.

Cortisone is so dangerous to the athlete because it inhibits just about every aspect of healing. Cortisone inhibits prostaglandin and leukotriene production. It also inhibits chondrocyte production of protein polysaccharides (proteoglycans), which are the major constituents of articular ground substance. Behrens and colleagues reported a persistent and highly significant reduction in the synthesis of proteins, collagen, and proteoglycans in the articular cartilage of rabbits who received weekly injections of glucocorticoids. They also reported a progressive loss of endoplasmic reticulum, mitochondria, and Golgi apparatus, as the number of injections increased.

Exercise has the opposite effect. Exercise has been shown to positively affect articular cartilage by increasing its thickness, enhancing the infusion of nutrients, and increasing matrix synthesis. However, the effects of doing them together were not studied until recently.

Dr. Prem Gogia and associates at the Washington University School of Medicine in St. Louis, Missouri, did an excellent study bringing out the dangers of an athlete exercising after receiving a cortisone shot. (Gogia, P. Hydrocortisone and exercise effects on articular cartilage in rats. Archives of Physical Medicine and Rehabilitation. 1993; 74:463-467.)

They divided animals into three groups:
1. Group One: received a cortisone shot
2. Group Two: received a cortisone shot and exercised
3. Group Three: control group, received no treatment

This study was done in 1993 and was the first study to look at the effects of exercising after receiving a cortisone shot. The authors performed this study because it is common practice in sports medicine to give an athlete a cortisone shot for an acute or chronic injury. Athletes are typically returning to full-intensity sports activities within a few hours to one to two days after receiving the shot. The results of the study were unbelievable. The animals receiving the cortisone shots showed a decrease in chondrocytes, but when they received the cortisone shot and exercised, the chondrocyte cell count decreased by another 25 percent. Degenerated cartilage was seen in all of the cortisone-injected animals, but severe cartilage damage was seen in 67 percent of the animals that exercised and received cortisone. The cortisone and exercise group also showed a significant decline in glycosaminoglycan synthesis compared to the other groups. The authors concluded, “...the results suggest that running exercise in combination with intra-articular injections results in damage to the femoral articular cartilage.”