Risk of Falling after Total Knee Replacement
Do patients with total knee replacements (TKRs) have trouble getting around obstacles? Are they more likely to trip and fall when both knees have been replaced? Researchers from the Motion Analysis Lab at the University of Chicago say "Yes" to both questions.
They studied 29 adults with bilateral TKRs and compared them to normal adults. All TKR patients were pain free, able to walk and climb stairs, and rise from a chair. Patients and normal subjects had 20/40 vision or better.
A special walkway was used to test everyone's ability to avoid obstacles. A band of light was flashed on the floor, and each person was to step over it. Patients with TKRs were 30 percent less likely to avoid the virtual obstacle. Type of joint implant didn't seem to make any difference on success rates.
Researchers also found success rates went down as body weight went up in both groups. The most important factor in avoiding obstacles was the time each person could stand on one leg.
The authors conclude that older adults with TKRs may be at risk for falling compared to healthy adults of the same age. TKRs are linked with impaired balance. Reduced balance puts patients at risk for falls.
Patients with bilateral TKRs generally have muscle weakness, decreased standing balance, and loss of joint position sense called proprioception. Knowing these risk factors for falls may help in planning a falls prevention program for anyone with a TKR and especially patients with bilateral TKRs.
Andreas C. Mauer, BA, et al. Bilateral Total Knee Arthroplasty Increases the Propensity to Trip on an Obstacle. In Clinical Orthopaedics and Related Research. April 2005. Vol. 433. Pp. 160-165.