Exercise for Functional Independence

As time passes the pains in the knee, the leg, the foot and whatever else might have been impacted by surgery subside and, gradually, end altogether. For many people, this marks the recovery they have long anticipated. Now they can get back to normal and lead the lives they had before their knee problems began. Not so fast! Do not assume that knee surgery is like flicking a switch and you can, with effort, go from old bad knee to good new knee and the light stays on. A more appropriate metaphor might be caring for a plant – just because you watered it last week doesn’t mean you don’t have to water it again this week.

A personal story. 14 months after my first TKR and 10 months after my second we went on a two-week trip during which time I walked between 8,000 and 10,000 steps every day. I felt fine, but when I returned home I was shocked to discover that I had lost 10 degrees of flexion on my left knee and a few on my right as well. Why? As my PT explained, I had subjected my knee to a great deal of stress during the day and had not taken care to reduce the “micro-inflammation” that had occurred as the result of my activity. Had I understood what I was doing to my knee and been able to anticipate the consequences, I would have concluded each day by taking an anti-inflammatory (such as Aleve) and icing my knee. And because I was doing so much walking, I had neglected my other exercises. This, however, is life – the new normal. Perhaps new knees should come with a reminder Use it or Lose it. Maybe a new app? Or just a post-it note on the fridge? In any event, to maintain the flexion you’ve worked so hard to achieve, it is critical to keep doing some set of exercises – whatever works for you. I refer to this as Exercise for Functional Living – making sure your knees will continue to perform so you can continue to thrive.

I’ve had several discussions with my tolerant PT as to why my legs responded to the increased amount of walking with a reduction in flexion. His more technical explanation is presented in the next section, Ground Reaction Forces and Neuroplasticity. Before we discuss the physiology behind the trade-off in walking and flexion, however, I’d like to review what we, as survivors of TKRs, can do to maintain the quality of life we’ve attained post-surgery.

To restate a point made throughout this website, just as no two knees (or TKR experiences) are the same, no two bodies are the same. Do not fall into the trap of comparing your healing process with someone else’s or feeling you are in a race to recovery and are always falling behind. One important and previously undiscussed dimension of recovery is the degree of laxity or flexibility in the inert tissue in our body. Inert tissue is tissue that does not contract, such as ligament, cartilage and the knee capsule (in contrast to tissue that does contract, such as muscle and tendon). The next section discusses how and why the laxity in our inert tissue affects our recovery. It is enough to say here that it does. Since I am on the stiff tissue end of the inert tissue laxity continuum, I need to do several exercises daily to maintain my balance and mobility.

We undertook the TKR journey for several reasons:
1. Eliminate pain in our knees and
2. Regain our functional independence – the ability to care for ourselves without having to rely on others.
Important knee-dependent quality-of-life functions – which we probably had compromised in the past – include getting out of chairs without assistance, getting into and out of cars, and climbing and descending stairs. All of these activities require strength, flexibility, and balance.

While we have discussed flexibility and strength throughout this site, we have only touched on the third important attribute – balance. Balance is the product of three body systems: the vestibular system (located in the inner ear), the visual system and the somatosensory system. All three must work together to enable the body to move as desired through space. Unfortunately, age-related skeletal and muscle loss contribute to a loss of balance. Exercising to increase the strength of the pelvic core, the hip and glute muscles will help to restore the body’s ability to balance, i.e., to take input from your foot through the muscles in your legs and up to your brain.

3 Way Band Pull:

Vision and Balance: Vision is also an important input to balance. An interesting challenge is to try and walk in a straight line while you turn your head from side to side, scanning the horizon as you walk. By shifting your vision from side to side you are changing the visual input that your brain has to process as you walk. This is a good exercise for training your brain to ‘feel’ the floor, enabling you to walk in a straight line regardless of where you are looking.

Quadriceps:  The importance of a strong quadricep to my recovery was repeatedly stressed by my PTs and my surgeon during the early weeks of my recoveries – and for good reason. The VMO (Vastus Medialis Oblique) is the quadriceps muscle that controls knee extension and stabilizes the kneecap as it tracks upwards. It cannot be activated unless the leg is nearly fully extended. For years, my crooked legs had prevented this important muscle from functioning and only when my leg achieved adequate extension was I able to begin trying to reactivate my VMOs. A good discussion of the VMO and how to strengthen it is available at: https://sportskneetherapy.com/the-best-vmo-exercises/

While doing full squats is probably beyond the reach of most TKR recipients, the following exercise is still of value.

Chair Squats: Stand in front of a wooden/hard-seated chair or bench. With straight arms lifted in front of you for balance and leading with your butt, bend your knees and angle backwards and down until your butt almost touches the seat. Return to standing position.  Repeat 10 times.

Ankle Exercise: