By Andrew mills
In a previous article, Prehabilitation Through Corrective Exercise: A Guide for Trainers, we explored how Certified Personal Trainers (CPTs) could help prepare individuals for a procedure like total knee replacement surgery. This article will focus on rehabilitation after total knee replacement (TKR).
The first TKR, otherwise known as total knee arthroscopy (TKA), was performed in 1968. Since then, knee replacement surgery has become more commonplace with significant improvements to the replacement models, surgical techniques, and rehabilitation process.
Today, according to the American Academy of Orthopedic Surgeons (2020), more than 790,000 knee replacements are performed each year in the United States. The chances for a Personal Trainer or Corrective Exercise Specialist to be working with a client having had knee replacement is relatively high.
REASONS WHY A CLIENT MIGHT GET A KNEE REPLACEMENT
There are many reasons why a client may choose to get a knee replacement. Still, it is usually related to a decline in quality of life associated with chronic knee pain and disability due to arthritis.
The most common form of arthritis is osteoarthritis and usually develops over time due to age-related “wear and tear.” Over time, as cartilage cushioning of the knee joint wears away, the bones begin to rub against each other, causing various issues, usually resulting in knee pain, inflammation, and stiffness.
Clients struggling with knee pain and stiffness may struggle with daily living activities such as climbing stairs, walking for extended periods, getting in and out of chairs and cars, and sleep disturbance. If knee complications due to arthritis were not enough reason to justify a replacement, Devers et al. (2011) suggested that impaired knee function can have dramatic implications for the rest of the body.
Even though surgery is usually very successful in resolving pain symptoms, the replacement alone is not enough to restore the individual’s knee mobility and movement confidence.
MOVEMENT COMPENSATIONS RESULTING FROM KNEE REPLACEMENT
The goal of a knee replacement is to establish a well-functioning, pain-free joint so the client may maintain a high quality of life and perform daily activities. However, a study by McClelland et al. (2017) found those with successful knee replacements were not utilizing their full range of motion even when it was available.
In other words, clients with knee replacements may be prone to movement compensation, especially during exercises requiring the use of their full available knee range of motion.
WHY KNEE REPLACEMENTS PRESENT CHALLENGES FOR CLIENT MOVEMENT
This lack of utilization has several suggested reasons having to do with physiological and biomechanical impairment, but also may also include psychological factors such as a lack of confidence in their knee’s ability to perform the desired movement (McClelland et al., 2017). Devers et al. (2011) suggest that knee flexion was a predictor for determining overall knee function.
A study by Verena et al. (2017) tracked patient joint mechanics after successful knee replacement while descending stairs.They also found patients were not utilizing their full available range of motion and presenting with movement compensations at the hip, knee, and ankle.
All three studies noted gait impairment. Kocic et al. (2015) concluded that after six months of rehabilitation emphasizing knee-flexion ROM and lower limb strength, knee replacement patients with a higher degree of knee-flexion reported less pain and stiffness and more significant function.
THE ROLE OF A CORRECTIVE EXERCISE SPECIALIST FOR KNEE REPLACEMENT CLIENTS
The NASM Personal Trainer or Corrective Exercise Specialist (CES) can play a significant role in both the “prehabilitation” and the rehabilitation process for individuals with TKA. Prehabilitation is often employed as a proactive approach to strength, stability, balance, and mobility in preparation for surgery or other medical intervention.
After surgery, rehabilitation can help the client improve joint range of motion and mobility, muscle strength, and integrated movement function to enable them to utilize their full available range of motion and reduce movement compensation. While working with a client who has had a knee replacement may seem like a daunting task, it doesn’t have to be.
Once they have completed their physical therapy and been cleared by their guiding physician to resume physical activity, their exercise programming should be approached using a comprehensive, integrated, and progressive process just like any other client.
CORRECTIVE EXERCISE PROCESS & CONTINUUM
The NASM approach to corrective exercise is a systematic process that identifies the problem, solves the problem, and then implements the solution (Fahmy, 2020). The three-step process is essential to remember when working with clients with a knee replacement.
IDENTIFY THE PROBLEM
Clients with knee replacement are likely to present with other health concerns, limited range of motion, and movement compensations. It is crucial to assess to fully identify the client’s problems that will need to be addressed. The health screening and Physical Activity Readiness Questionnaire for Everyone (PAR-Q+) is the perfect place to start.
Assuming the client has a physician’s clearance for exercise, and nothing came up during the health screening or PAR-Q+ that would cause concern, the Corrective Exercise Specialist should have the client complete a movement assessment.
Movement assessments include transitional movement, loaded movement, dynamic movement, and joint mobility assessments. Transitional movement assessments such as the overhead squat assessment are a great place to begin.
Because a limited range of motion or decreased confidence in the knee may lead to movement compensation, a transitional movement assessment provides the CES insight into how the rest of the kinetic chain may be affected by the replacement. Also, highlight other potential issues that may impact the function of the knee itself. Clients with knee impairment may demonstrate knee valgus, varus, or an asymmetric weight shift during the assessment.
It is common for a client with a knee replacement to have a limited ability to achieve the ideal depth for transitional assessments because of potential limitations or restrictions in joint mobility.
Depending on the movement assessments results, the CES may perform joint mobility tests to gain further insight into the client’s faulty movement patterns. Although many knee replacement clients lack knee-flexion, the CES should not assume that every knee replacement client suffers the same impairment(s).
Recommended joint assessments include the modified Thomas test, prone knee flexion test, adductor test, active knee extension test, and ankle dorsiflexion test (Fahmy, 2020). The results of these tests will help determine the range of motion for hip extension, knee extension and flexion, and hip abduction, all of which may be compromised for someone with a knee replacement. The combined assessment results will allow for effective programming when solving the problem, which is the next stage in the corrective process.
SOLVE THE PROBLEM
Solving the problem pertains to the design process of the corrective exercise program. The corrective exercise program consists of four phases within a continuum: Inhibit, Lengthen, Activate, and Integrate. The Inhibit phase will include the myofascial techniques used to reduce tension or activity of overactive tissues. The Lengthen phase consists of the stretching techniques necessary to increase tissue extensibility, length, and range of motion.
The Activation phase is used to increase, reeducate, or improve the activation of underactive tissues. The client’s assessment results will guide which muscles will require inhibiting/lengthening and activation. Integration includes techniques used to retrain the entire neuromuscular system’s collective synergistic function through functionally progressive movements.
Suppose the CES found the client with knee replacement demonstrated feet turn out and knee valgus during the overhead squat assessment and presented with limited knee flexion and hip abduction and ankle dorsiflexion. In that case, their programming may look like this:
Inhibit – Myofascial rolling: Adductors, rectus femoris, TFL/IT band, biceps femoris (short head), soleus, lateral gastrocnemius.
Acute variables: Hold areas of discomfort, 4-6 repetitions of slow active joint movement, spending between 90 and 120 seconds per muscle group.
Lengthen – Static stretching: Adductors, rectus femoris, TFL/IT band, biceps femoris (short head), soleus, lateral gastrocnemius.
Acute variables: Static stretches should be held for at least 30 seconds.
Activate – Isolated Strengthening: Floor bridge with miniband around knees, Wall slides, Standing quadricep with cable resistance, medial hamstrings with cable resistance, medial gastrocnemius with band resistance, posterior tibialis with band resistance.
Acute variables: Using cable or band resistance and bodyweight 10-15 reps with a 4-second eccentric, 2-second isometric hold at end range, and a 1-second concentric tempo.
Integrate – Integrated dynamic movement: multiplanar tube walk with miniband around knees, step-up to balance, and “drop” into an athletic position with stabilization.
Acute variables: 10-15 reps under control
Use the resources NASM provides when determining which muscles are overactive and underactive. Resources such as the Postural Assessment Solutions sheet guide programming after the client completes the appropriate movement and/or mobility assessments.
The trick to figuring out which exercise is best for activation is to identify the target muscle’s concentric function and then have the client perform that motion in a position or environment that prevents the synergists from taking over and dominating the movement.
Integration exercises should fit within the client’s available range of motion and threshold of control and be progressively challenging. Because the lower extremity and knee must stabilize and control forces in all three planes of motion, integration should challenge alignment, stability, and control in each plane, beginning with the sagittal plane.
IMPLEMENT THE SOLUTION
The last step of the corrective exercise process is implementing the solution developed during the second step. Implementation includes the coaching of the selected techniques, cueing, and management of the client’s program. This period may begin once the client receives physician clearance and remain in effect until knee function and mobility are fully optimized. Ideally, with the CES’s support, the client would also regain movement confidence promoting utilization of their full available range of motion.
During implementation, the CES should demonstrate each of the exercises as needed, provide ample external feedback and cues to guide the client, and progress or regress the exercises as necessary to promote quality movement practice and reduce compensation. A corrective program may be performed 3-5 days per week based on the client’s tolerance and recovery.
While the corrective programming can stand alone as a 30 to 60-minute stand-alone program and achieve great results, it is best when integrated with more extensive, more comprehensive programs using NASM’s Optimum Performance Training (OPT) Model.
The CES may also use the client’s corrective exercise program as a component of the warm-up of a more comprehensive and integrated health and fitness program that fully addresses core stability, balance, reactivity, and resistance training needs. Time spent on a corrective program used as a movement prep doesn’t usually require more than 5-15 minutes (Fahmy, 2020).
Additionally, the CES should reassess the client regularly to ensure progress. If the knee replacement client begins to experience pain or a lack of progress is occurring despite quality programming and client adherence, the client may need to be reevaluated by their physician or their circle of care expanded.
It is important to remember the NASM CES is only one member of a potentially larger team caring for their client. Sometimes other providers and practitioners on that team need to be leveraged to address issues or complications that may arise that are outside the scope of a personal trainer.
With more than 790,000 TKR surgeries performed each year in the United States, there is ample opportunity for Personal Trainers to work with individuals seeking to maximize their movement quality and confidence after TKR. The goal of a knee replacement is to establish a well-functioning, pain-free joint so the client may maintain a high quality of life and perform daily activities.
While it is common for a client with a knee replacement to present many movement challenges during rehabilitation, the NASM CES can play a significant role in optimizing a knee replacement client’s movement quality, strength, stability, balance, mobility, and confidence during rehabilitation.
Using the corrective exercise process, the CES has the tools necessary to systematically identify mobility and movement issues, develop a plan of action, and implement an integrated corrective strategy.