Knee Replacement Rehab: Activating Quadriceps Post-Op

On average, individuals with knee osteoarthritis have a 20 percent quadriceps deficit prior to undergoing a traditional total knee arthroplasty (TKA).¹ At one year post-op, this deficit has been reported to be 40 percent, despite standard rehabilitation programs.^{2, 3} Researchers have linked the decline in walking speed, stair climbing ability, and falls to the persistent quadriceps deficit.²

NMES Improves the Quadriceps Deficit

How can we address this deficit and return our patients to improved strength and range of motion? Neuromuscular electrical stimulation (NMES) is one option.

When researchers incorporated NMES into post-operative rehabilitation to augment traditional strengthening exercises, they found that the patients who received NMES walked and performed stairs faster and with fewer torque deficits than patients who did not receive NMES as part of their rehabilitation program.^{4, 5, 6}

What makes NMES effective? Consider these two key components:

1. Basic electrical stimulation modality principles

NMES selectively recruits fast twitch type II muscle fibers before slow twitch type I fibers. Type II fibers are the first to atrophy following disuse immobilization. Therefore, we can speculate that NMES provides the necessary neural drive to the quadriceps muscle, reducing the inhibitory effects of disuse immobilization.

2. The effects of post-operative effusions on quadriceps inhibition

We can also clinically reason that post-operative NMES delivered to the quadriceps has a muscle-pumping effect that reduces effusion.

What if You Don’t Have an NMES Unit?

All my life, I have been curious about how things worked and have sought out the common denominators to successful methods. This naturally led to me asking, “How can I implement this information to enhance my clinical outcomes if I do not have an NMES unit?”

Since I didn’t want to deprive my patients of the benefits of this strategy, I developed an alternative therapeutic approach—neuromuscular exercises called the Retro Step (RS) and the Church Pew Exercise (CPE).

The Retro Step can be done within the first couple of days post-op and has the following advantages over traditional non-weight-bearing supine quad sets:

1. Weight bearing
2. Focuses on the stance phase of gait
3. Creates eccentric contraction
4. Most importantly, triggers an involuntary muscle contraction

The Church Pew Exercise also allows for weight bearing and involuntary muscle contraction.

By including these two exercises into the traditional post-op set of “bed exercises,” you can incorporate the principles of NMES to exceed your current outcomes and achieve a more normal gait more quickly for your TKA patients.