Section 1.1 The Study Overview

In a study involving 140 participants scheduled for TKR, subjects underwent a 12-week exercise program. They attended a single physical therapy session where they learned a knee-extensor resistance exercise to perform at home.

This exercise involves sitting on a chair with an exercise band secured around the ankle and attached to a door behind the chair. The patient extends the leg until the knee is straight, creating tension in the band.

The band used in this exercise provides 35–80 pounds of resistance, depending on how much it is stretched. Although anchored to my squat rack in the example, any sturdy anchor or door can be utilized.

Section 1.2 Exercise Protocol

Participants completed three sets of twelve repetitions, focusing on a specific timing for each phase: a three-second concentric phase (straightening the leg), a one-second isometric phase (holding the position), and a four-second eccentric phase (lowering the leg). The resistance was adjusted to match their twelve-repetition maximum, and they continued until they reached muscular fatigue. While reaching failure is not always necessary, it was appropriate given the limited exercise volume.

At the end of the 12-week period, participants were reassessed regarding their need for surgery. Out of the 117 patients who followed up, 79 (67.5%) opted to postpone their surgeries.

Evaluating Exercise Outcomes

While there was no significant improvement in strength among the groups, this is expected due to the low frequency of exercise. The six-session group may have seen some muscle gains, contingent on adequate protein intake. Regardless, the intervention successfully demonstrates the impact that even a small amount of exercise can have.

I frequently discuss with orthopedic residents how they assess the success of their prescribed exercises. Various studies indicate that success can be measured through factors like pain reduction, functional improvement, strength enhancement, mobility, muscle growth, endurance, power, or fear of movement. Understanding the desired outcome is crucial for determining the appropriate exercise dosage.

Although we know that increased volume is essential for muscle growth and near-maximal force is necessary for strength development, this study suggests that high volume isn't a prerequisite for pain relief and improved function.

A Balanced Approach to Knee Health

Does this imply that merely performing a few sets of knee extensions can prevent surgery or alleviate knee pain? Unfortunately, the answer is no; this represents just a fragment of a more complex solution.

It's vital to adhere to the minimum physical activity recommendations set by organizations like the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC). Adults should aim for at least 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous-intensity exercise each week. This can include brisk walking, cycling, swimming, or running, along with muscle-strengthening activities at least two days a week.

Additionally, focusing on strengthening the quadriceps through knee extensions and squats should be a primary objective. Factors such as sleep and nutrition also play a role in pain sensitivity, exercise performance, and weight management.

Beginning with two days of knee extension exercises (3 sets of 12 reps) weekly can be a beneficial start for those dealing with knee osteoarthritis. For a comprehensive health plan, consider consulting your physical therapist.

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