From the study:
SUBJECTS:
Twenty-nine individuals 1 year following TKA (13 women, 16 men) and 40 age- and gender-matched control subjects (18 women, 22 men) were assessed.
METHODS:
Walking speed, stair-climbing ability, knee torque (in newton-meters), and total work performed during 15 repeated contractions were evaluated.
RESULTS:
Walking speeds for men with TKA were 13% and 17% slower at normal and fast speeds, respectively. Their stair-climbing ability was even more compromised (51% slower). Walking speeds for women with TKA were 17% and 18% slower at normal and fast speeds, respectively. Similarly, their stair-climbing time was more compromised (43% slower). Men with TKA were 37% to 39% weaker and performed 36% to 37% less total work of their knee extensors compared with the control subjects. Similarly, women with TKA had knee extensor strength deficits of 28% to 29% and performed 24% less total work.
CONCLUSION AND DISCUSSION:
One year after TKA, marked physical impairments and functional limitations persisted. [Walsh M, Woodhouse LJ, Thomas SG, Finch E. Physical impairments and functional limitations: a comparison of individuals 1 year after total knee arthroplasty with control subjects.
Chad’s comments:
I recently did a blog on a similar study but what I liked better about this older one was the quantification of gait speed and hamstring strength between those who are post-op total knee replacement and age matched normal subjects without knee pathology. The entire article should be read by physical therapists as it is full of great information that should affect how we practice. Normal gait speed of women aged 62 years old was 3.1 mph, but if they were asked to walk fast it was 3.7 mph. For men aged 64, normal gait was 3.4 mph but when walking fast could do 4.1 mph. I test most of my patients on gait speed as it correlates with so well not with knee function but also longevity for a host of reasons (future blog) and 3.7 to 4.1 is pretty fast for any age and a post-op knee replacement should be able to get there. Also of note was the citation that you need to walk 2.68 mph to safely cross an intersection and that 55% of the total knee patients studied had to walk at a faster pace than usual to get there, and a full 17% just weren’t capable even though the subjects in the total knee replacement group women were only 61 years old, and the men 66.
Also of interest to me was the was the hamstring strength loss of 27% in women and 35% in men which was pretty similar to the 29% and 27% female and male quadriceps strength loss, yet most of the focus on rehabilitation programs and research is on the quadriceps. This includes the abstract of this study that did not mention the profound knee flexor strength loss. In fact every EMS study I have blogged on, has only put the EMS on the quadriceps, yet strength and conditioning research shows it works, and is complementary with progressive resistance exercise on all muscles. Taken with other studies showing the importance of hip musculature in post-op knee function it is clear that the entire leg needs to be strengthened and it probably wouldn’t be a bad idea address core musculature as well.
The good news is that this study is 16 years old and total knee replacement surgery has progressed since, then, the procedure is often less invasive, with a faster return of function and quicker resolution of pain. Also since then newer research has been done showing early aggressive rehabilitation is both effective and well tolerated, while EMS technology has become better and less expensive making home use practical. However bad new is regardless of advancements in technology and knowledge, newer studies show not a lot has changed in recent years and deficits usually persist long after total knee replacement. So probably if you are spending valuable therapy time being iced, heated, rolled on a foam cylinder, and massaged with various implements you probably aren’t optimally setting yourself up for success.
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