New study recommends bike and walk exercises for replaced knees.
Patients who under go knee arthroplasty should avoid golf, running, tennis or games of similar intensity. Instead they should concentrate on walking and exercising on a bike, a new study shows.
knee replacement is a very common procedure done for knee osteoarthritis. Biking and treadmill walking appear to be two of the gentlest exercises for replaced knees with an artificial joint, researchers found.
The researchers found that higher impact sports such as jogging and tennis generated higher forces on new knees, according to study author Dr. Darryl D’Lima, director of the Orthopaedic Research Laboratory at Scripps Clinic, in La Jolla, Calif.
More surprisingly, golf swings were also tough on the knees, although D’Lima was quick to point out the swings make up just part of the exercise in a round of golf.
The study has been recently presented in at the American Academy of Orthopaedic Surgeon’s annual meeting in San Francisco. The study was initiated by Dr. Clifford W. Colwell, director of the Shiley Center for Orthopaedic Research & Education at Scripps.
In total knee arthoplasty, the original joint is replaced by one made of various materials, such as plastic and metal.
Surgeons typically advise patients to resume physical activity when they are able. But advice about which activity is best has been subjective, D’Lima said. So, his team decided to measure forces on the knee while patients took part in a variety of exercises.
In the study, D’Lima’s team measured forces on the tibia, or shinbone, in four patients who had undergone Total knee arthoplasty. These four patients had a specially designed joint that allowed forces to be measured from inside the implant.
A year after their surgery, each of the four patients jogged, played tennis, did golf swings, walked (on a treadmill and on level ground) and biked while the forces to their knee area were measured.
Golf swings produced forces of 4.5 times body weight on the forward knee and 3.2 times body weight in the opposite knee, the researchers found.
D’Lima noted that the forces produced by the golf swing, however, occur in an instant, while the forces produced by jogging are constant. “I think golf should be OK,” he said. “It’s more of scientific interest.”
There were some other surprises, D’Lima said. “We expected that walking on a treadmill, which is more controlled, would be better than biking” the researcher noted. But biking actually won out, he said.
Other details on the results:
- Biking generated the least force, producing impact of about 1.3 times the person’s body weight.
- Treadmill walking was next best, producing forces of 2.05 the body weight.
- Walking on level ground generated forces of 2.6 times the body weight.
- Tennis produced forces of 3.1 to 3.8 times the body weight, with serving producing the highest impact.
- Jogging produced forces of 4.3 times body weight.
Modification of certain high-impact exercises could help, he said. For avid golfers, “it’s possible you could modify your swing,” D’Lima says. Golfers could get a high-tech evaluation of their swings, offered by many golf club makers, or ask their pro about modifying the swing to exert less force on their knee, D’Lima suggested.
However, for more strenuous high-impact pursuits such as jogging, people who’ve undergone knee replacement should make a permanent switch to another form of exercise, the expert said.
While the study confirms the experts’ suspicions about which activities are more stressful on the new knee, it can’t be determined from the study if the increased forces will lead to a higher
Source: Medline plus via Healthday News
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