After a total knee replacement (TKR), regaining full knee extension is crucial for improving quality of life, not just mobility. While passive knee extension exercises are important, they must be complemented by active exercises to solidify these gains. The Balance Matters System addresses this need by integrating auditory and tactile feedback, offering an advanced, effective, and engaging approach to motor control training.

Why Motor Control Training Matters

Regaining full knee extension after TKR is vital for enhancing overall quality of life, as adequate knee extension is essential for smooth and efficient walking, allowing for proper stride length and balance. Many patients experience quadriceps lag (Q-lag), a condition where they struggle to fully extend their knee despite surgical correction. Research indicates that overcoming this lag requires a substantial 60% increase in quadriceps contraction force to extend the knee from −15 to 0 degrees (McGinn er al, 2018). This limitation in knee extension isn’t merely uncomfortable; it contributes to higher pain levels and reduced functionality.

Achieving full knee extension after total knee replacement is not only critical for improving walking mechanics and reducing pain, but it also directly correlates with key functional outcomes, such as the Oxford Knee Score (OKS), which measures overall knee function and recovery. Reduced knee extension during gait has been associated with lower Oxford Knee scores (Booij et al., 2021). Even a one-degree deviation in knee extension can reduce the OKS by up to 1.6 points, emphasizing the importance of full knee extension during everyday activities like walking.

Patients with suboptimal OKS scores typically exhibit limited knee extension during gait, even when no mechanical constraints are present. This suggests that motor control limitations are a significant factor. Specifically, the knee extension angle at initial contact and late stance has a strong correlation with OKS scores. For each degree of reduced knee extension, the OKS can drop by 1.0 to 1.6 points, with the most significant effect observed at initial contact ( Booij et al, 2021).

Motor control issues can stem from several factors, including post-surgery symptoms such as instability and pain, which can hinder knee extension. Additionally, many patients retain preoperative gait patterns developed to manage arthritic pain, which may persist even after the pain subsides. These gait patterns often involve increased co-contraction of the knee's flexor and extensor muscles, leading to inefficient movement and greater stress on the knee as well as the surrounding joints. Faulty gait patterns can also affect the hips, trunk, neck, ankles, and feet, causing compensatory changes up and down the kinetic chain. Additionally, it's important to consider pre-TKR habits that develop due to pain, which may further contribute to these dysfunctional movement patterns. Future research should not only focus on identifying the underlying causes of restricted knee extension, such as scar tissue, but also on developing effective programs that target motor control—an often-overlooked aspect in rehabilitation.

Balance Matters activates the patient’s motor control capabilities, a critical yet often underutilized factor in restoring range of motion, while playing a pivotal role in enhancing gait patterns and overall knee function.  It's important to reconsider the traditional stretch/strengthen approach and allocate more time incorporating motor control training, as this will lead to better patient outcomes and improved quality of life.

Clinically, I have observed positive results with motor control training following PROM training and would like to see these findings confirmed in larger studies. Exploring how the Balance Matters System can complement motor training may further enhance outcomes and provide additional benefits for patients.

The Balance Matters System: Enhancing Knee Extension Through Feedback

Post-TKR motor control issues have never before had the opportunity to leverage both auditory and tactile senses to improve lower extremity motor control—until now. The Balance Matters System uses a combination of auditory and tactile feedback to help patients improve motor control during knee extension exercises. This revolutionary Balance Matters System integrates auditory and sensory feedback, offering a new way to benefit patients with motor control deficits.

Here’s how it works:

Supine Position with Footpads: Patients lie in a supine position with footpads under their knee, accommodating their current range of motion. The goal is to gradually reduce the number of pads as knee extension improves. Instead of using traditional cues like "squeeze your quad," patients are instructed to "press down to activate the clicker." The absence of a clicking sound indicates that the isometric contraction was unsuccessful, while an early 2^nd click suggests the contraction wasn't held long enough. With the Balance Matters System, clients can easily recognize their progress: a well-timed click signals a successful contraction, reinforcing proper motor control. This unique auditory feedback motivates clients by allowing them to practice independently, both in the clinic and at home, ensuring continuous improvement between sessions. It offers an innovative, hands-free approach that sets it apart from traditional methods.

Standing Against the Wall: As patients progress, stand with back to a wall. Here, they continue to use the clickers to reinforce knee extension in a functional posture. The tactile and auditory feedback enables the patient to recognize when they have achieved the correct extension while standing. The Balance Matters System is designed to progress the difficulty and to ensure functional relevance.

Terminal Stance with TheraBand combined with Auditory Feedback: The client uses a TheraBand during heel strike and terminal stance to actively engage in maximizing knee extension awareness. By feeling the resistance, the patient gains valuable feedback that informs their movement, empowering their brain and facilitating interoceptive learning. The auditory feedback from the clickers can further enhance this experience, ensuring the client fully extends their knee.  

Reclaiming knee extension after a total knee replacement can be a significant challenge, but with effective motor control strategies, patients can regain their mobility more quickly and improve their chances of successful rehabilitation. The Balance Matters System utilizes innovative auditory and tactile feedback to engage patients actively in their recovery, enhancing motor control and leading to better outcomes in functional activities, gait, and overall quality of life. By investing in a program that offers diverse practice options and measurable motor control strategies, you are making a valuable choice for your patients' recovery journeys.

If you’re looking for additional strategies to assist patients who may have plateaued, or if you aim to enhance your patients' motivation through auditory feedback, don’t hesitate to reach out.

We are here to support you every step of the way—let’s work together to improve your patients' recovery experiences!

McGinn TL, Etcheson JI, Gwam CU, George NE, Mohamed NS, Mistry JB, Ananaba U, Bhave A. Short-term outcomes for total knee arthroplasty patients with active extension lag. Ann Transl Med. 2018 Jun;6(11):204

Booij, J. Harlaar, B.J. van Royen, P.A. Nolte, D. Haverkamp, J.C. van den Noort, Limited knee extension during gait after total knee arthroplasty is related to a low Oxford Knee Score, The Knee, Volume 33, 2021, Pages 176-184