Getting the Most out of Your Total Knee, Strength Matters

So I read ALL of Dr. Tarlow’s blog, who first suggested I start a blog on my own. It took me a few weeks but I read every post, and learned A LOT about knee surgery from the surgeon’s perspective.  One topic he wrote about that sticks in my memory showed the more you like your doctor the more you will pay for medical expenses, and the more likely you are to die young. So maybe  a good bedside manner isn’t everything,  and maybe it’s better if your health care professional doesn’t just tell you what you want to hear.  However,  reading back to 2010 I came across this one…

“Outpatient Physical Therapy Does Not Improve Functional Outcome After Total Knee Replacement”.

…and I wanted to talk about it as I have seen a couple others like it.  The study cited was done in the United Kingdom and they found exactly what was noted. Six weeks of standard outpatient physiotherapy did not improve knee range of motion after total knee arthroplasty when measured one year later. However I think my profession is getting a little short changed as in those 6 weeks the mean number of treatments attended was only 7.3 with no description of the duration of each visit and what was being done during the visit. If you do 7 sessions of exercise and stretch over 6 weeks I wouldn’t expect much difference one year later. Still it makes you think…. There are a number of other studies which found a similar lack of result, and physical therapists should think about what they are doing and whether it is getting patients back where they need to be, or if they are just humoring the patient while they get better on their own. However, a recent study looked at this very thing where researchers found “Early High-Intensity Rehabilitation Following Total Knee Arthroplasty Improves Outcomes” that patients who had 25 visits over 12 weeks (including relatively intense progressive resistance exercise) improved more in strength and function than those who had 10 visits over 6 weeks following a standardized protocol with no external resistance greater than 10 lb. Follow up measurements were also performed up to one year post-op. There were substantial differences between groups at the one year follow up, all in favor of the high intensity (HI) treatment group:

     Time/Variable HI Group Control Group
      Stair Climbing Test    10.4s    17.3s
      Timed up-and-go test    6.4s    8.8s
      6 minute walk test    552m    470m
      Knee Flexion    122deg    117deg
      Max Voluntary Contraction    1.7Nm/Kg    1.4Nm/Kg
      Quadriceps Activation    89.1%    79.7%

 

Researchers conclusions: “The high-intensity rehabilitation program described in this study demonstrated significantly greater short-term and long-term strength and functional performance increases compared to a lower intensity rehabilitation program. The high-intensity rehabilitation program was initiated immediately following hospital discharge and did not compromise knee ROM outcomes, cause musculoskeletal injury, or increase pain in the small group of patients. Key differences between the 2 programs were a greater number of treatment sessions over a longer period and the use of machine-based resistive strengthening and higher level functional exercises.”
I think it’s worth noting that both the HI group and the control group in this study had greater knee flexion at one year post-op (122 and 117 deg) than both therapy and no therapy groups in the UK study (109.9 and 109.3 deg). Much depends upon the fitness of the patient prior to surgery and how active they want to be afterwards. If the patient is younger, already active and will continue to exercise independently, less therapy is needed once they know what to do. If the patient is badly deconditioned from years of inactivity (often due to the knee arthritis itself) it takes longer to build back strength levels that were well below normal pre-op and likely years before the surgery as well. As noted in the high intensity study, I think post-op TKA is where weight machines shine. They can be progressed from light to heavy all while maintaining and pushing the patient into ever-increasing ROM. A number of bodyweight and even free weight exercises are at a disadvantage early on; while they can provide overload in functional patterns the resistance levels are too great to allow working the muscle and joint through a full range of motion. Later as strength levels and ROM increase, the bodyweight, free weight, and cable exercises become more efficient for fitness and integrating core strength and endurance with that of the knee.

Not mentioned in the above studies, electric muscle stimulation (when used properly) has been shown to go a long way towards preventing post-op muscle atrophy and restoring strength, even when pain and swelling are otherwise inhibiting a quality muscle contraction, but that’s the subject of my next blog. So much for words, here’s an example of how I treated a patient who had bilateral TKAs 5 weeks post-op to the day:

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As always, if you have any further questions or need for clarifications, please don’t hesitate to ask. Being aware that some of my blog ideas are contentious and occasionally a bit out of the field of my expertise, I encourage my readers to come forth with any questions/comments that are of interest or concern. Your comments are valued and welcomed.

Chad Reilly is a licensed physical therapist, located in North Phoenix, practicing science based medicine with treatment protocols unique and effective enough to proudly serve patients from Phoenix, Scottsdale, Mesa, Chandler, Tempe, Peoria, and Glendale.

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