Total knee replacement surgery is one of the most commonly performed orthopedic surgeries in the U.S. for individuals older than 40. Given historical trends, these procedures are anticipated to increase in volume by an estimated 143% by 2050.
Knee replacement surgery is widely considered a safe and effective surgical option for patients with end-stage osteoarthritis or inflammatory arthritis of the knee. The surgery aims to maximize the quality of life for patients by reducing pain and improving joint functionality. Unfortunately, research estimates between 1 and 10 percent of patients may experience persistent pain, limited range of motion and loss of function after surgery. This rare but devastating outcome is thought to be associated with arthrofibrosis or scar tissue build-up around the joint which ultimately has a negative impact on an individual’s daily activities and affecting emotional well-being and satisfaction. Thankfully there are remediation treatment options to consider in this situation. One non-invasive, safe, and effective possibility is manipulation under anesthesia (MUA).
Manipulating the knee joint under anesthesia aims to forcefully release fibrous adhesions formed after surgery. It is considered a simple and effective medical procedure performed under general or regional anesthesia, ensuring complete muscle relaxation without any pain experienced. The procedure uses force to overcome adhesions in a controlled manner. While lying on their back, the patient's hip is flexed to a 90-degree angle, and the lower leg is used as a lever to bend the knee until a firm endpoint is reached. Force is also applied to the kneecap to free adhesions found there. These movements are repeated several times until the best range of joint motion is achieved.
Sam, a 44-year old mother and second-grade school teacher suffers from painful osteoarthritis. She underwent knee replacement surgery for both knees. However, 3 months after her surgery, she continued to experience intractable pain, swelling, and an inability to fully bend her knee. She was using a walker to assist her and could not tolerate long periods of standing. She struggled with basic daily activities and became increasingly despondent. Clinical evaluation showed that Sam was not able to bend either knee to 90 degrees. At this point, the healthcare team suggested Sam consider the MUA procedure to release the scar tissue to help move her recovery forward.
Over time, we know that adhesive tissue tends to increase in quantity and maturity. This leads to progressively worsening pain and loss of joint mobility. Literature suggests that earlier MUA intervention provides better outcomes and is more effective. Still, there is no clear consensus on the timing, and MUA may still be effective when performed later. Because clinical improvement after replacement surgery should occur between 6-12 weeks — orthopedic practices often apply a generic 90 by 90 rule of thumb. The rule signifies the ability to bend your knee to 90 degrees within 90 days after surgery. If unable to attain the 90 by 90 goal, MUA is often recommended. This is not a hard and fast rule, and each patient is individually assessed throughout the recovery period.
Not everyone will be a candidate for MUA, and there are risks involved. Since force is being applied to the joint during the procedure, there is a possibility of bone fracture. Patients with osteoporosis or any other bone-weakening illness might be cautioned against the procedure. Other risks include bleeding into the joint and wound rupture. It is also important to recognize that any procedure involving anesthesia is taxing on the body and carries additional risks. It is prudent to discuss all risks and benefits with your surgeon and healthcare team fully.
MUA intends to relieve pain and discomfort and help further increase the functional range of motion in the knee joint. Biomechanically we require a knee to flex or bend, ranging from 67 degrees for walking through to 105 degrees to rise from a low chair; and 115 degrees to squat or kneel. Immediately following the procedure, joint mobility is notably improved. Research studies have recorded an average increase in flexion of 29 degrees immediately after MUA, with continued improvements over time. Individual outcomes do vary. Current literature indicates having had two or more prior knee surgeries or injury to the joint, or a stiffer knee with less than a 70-degree bend 90 days after your replacement surgery, might yield less favorable outcomes.
Sam underwent her MUA 4 months after her initial knee replacement surgery. Physical therapy is started immediately following the MUA to ensure the best outcomes. During her initial evaluation less than 24 hours after the procedure, Sam could bend both knees by herself to 90-95 degrees, something she could not do before. Less than a month after her MUA, and with continued physical therapy, she reached a 115/120 degree bend. Sam had several risk factors; early-onset osteoarthritis, high body mass index (BMI) and previous knee surgeries. These factors complicate Sam's recovery and may have lead to her failure to attain the 90 by 90 goal. Still, she told me if given a choice again; she would make the same decision. Sam smiled and told me she no longer relies on her cane to walk, can walk up and down stairs almost normally and she is eager to start driving again.
The American poet Sheldon Silverstein wrote in his poem "Stop Thief!", "...Help me please. Someone went and stole my knees. I'd chase him down but I suspect my feet and legs just won't connect." Our knee forms such an integral part of daily life and activities— yet we seldom appreciate that it is one of our most stressed and complex joints, needing 10 muscles for movement and stability, and requires varying degrees of flexibility to get us through the day.
Next Monday, in part 2 of this article, we examine factors that might predispose a patient to scar tissue induced persistent pain and limited functionality after knee replacement surgery; and possible steps to avoid this.
This column is a monthly feature of “Health & Exercise Forum” in association with the students and faculty of Geisinger Commonwealth School of Medicine.
Author: Hendrik Marais, MD, MS
Hendrik Marais, MD, MS, received his Doctor of Medicine degree from Geisinger Commonwealth School of Medicine in 2015 and his Master of Science degree in Global Medicine from Keck School of Medicine at USC in 2019. He is passionate about creating positive and empowered patient health outcomes. He grew up in South Africa and currently calls Scranton, PA home – where he enjoys cycling, swimming, and discovering the beauty of NEPA. He is a member of the American Medical Association, American Public Health Association, and the International Society of Physical and Rehabilitation Medicine. He plans to pursue a clinical career in physiatry.
NEXT MONDAY – Read Dr. Paul J. Mackarey “Health & Exercise Forum!” Part II of III on Recovery From Knee Surgery
This article is not intended as a substitute for medical treatment. If you have questions related to your medical condition, please contact your family physician. For further inquires related to this topic email: firstname.lastname@example.org
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Paul J. Mackarey PT, DHSc, OCS is a Doctor in Health Sciences specializing in orthopaedic and sports physical therapy. Dr. Mackarey is in private practice and is an associate professor of clinical medicine at Geisinger Commonwealth School of Medicine.