Total knee arthroplasty (TKA) is one of the most popular surgical procedures today. It is
designed and proven to effectively reduce pain caused by end-stage osteoarthritis.
Despite its achievements, up to 25% of patients remain dissatisfied after the procedure
due to lingering pain, amongst other complaints. Post-operative swelling of the knee and
leg is thought to be a contributor to this persistent pain.
Traditionally, a standard gradient compression stocking is applied to the knee and leg
after surgery to reduce this pain and swelling. However, due to ineffectiveness or
patient non-compliance, compression stockings are often not entirely successful at
preventing edema. The recently developed NCPS is a lower extremity garment comprised of a
technical fabric that is thought to be able to prevent edema and reduce pain all in a
comfortable, user-friendly manner. The purpose of this study is to determine if the NCPS
is effective at improving post-operative pain, swelling, ROM and analgesic use associated
with TKA.
Pain and prolonged recovery time associated with post-operative swelling are two factors
that contribute to patient dissatisfaction following TKA. Swelling of the knee following
TKA is caused by intraarticular bleeding and inflammation of the periarticular tissues,
which can lead to a decrease in functional performance including pain and delayed
rehabilitation. In a study by Noble et al, 1/3 of dissatisfied patients reported that
their knees swelled at least once per week, leading to pain and discomfort1. Decreased
quadriceps strength following knee surgery has been shown to prolong recovery1-8. Fahrer
et al showed that knee effusions inhibited reflex neurons and altered kinetics and muscle
activity in quadriceps, which ultimately causes decreased strength2. Holm et al later
showed us that knee swelling played a part in post-operative quadriceps strength
following TKA3. Ultimately, if post-operative swelling can effectively be reduced,
patient recovery could be expedited and patient satisfaction could be improved.
Compression stockings have been utilized to attempt to reduce post-operative swelling.
Compression works to prevent swelling by reducing the hydrostatic pressure in the leg.
Reducing hydrostatic pressure prevents the capillaries from oozing and allows blood to
move freely from the superficial to the deep venous system, subsequently allowing excess
fluid to flow away from the interstitial space9.
More recently, the use of gradient compression stocking following TKA has come into
question for its efficacy. While the application of external pressure from these gradient
compression stocking is beneficial for a period, they are often unable to exert a
sufficient amount of pressure long enough to prevent painful edema for an extended amount
of time. A study by Bowling et al showed that these garments showed sufficient
compression during the first few hours after surgery, but the pressure they applied
dropped with time and required daily measurements and refitting to maintain appropriate
and therapeutic compression10. This poses a problem not only medically, but financially
as well. These compression stockings lose their fit so quickly, new ones must be
prescribed frequently, leading to costly bills for the patient. It's clear that
compression stockings are not as effective as once thought when it comes to controlling
pain and swelling post-operatively.
A potential solution to the problems posed by traditional compression stocking is the
NCPG. The garment is comprised of a semi-conductive material ground to nanoparticles that
are embedded into the fibers, formed into a three-dimensional woven fabric for optimized
comfort. Instead of relying on compression, NCPS utilizes the body's own thermal energy
to generate infrared energy. The infrared energy generated is reflected back at the body
and modifies cellular activity at the level of the mitochondria through a process known
as photobiomodulation14-15. This process of photobiomodulation is hypothesized to improve
swelling and tissue healing by increasing the activity of mitochondria and the
availability of cellular energy in the form of ATP.
This study seeks to determine if NCPS use of infrared energy is more successful at
reducing pain and swelling following TKA than traditional gradient compression dressing.
We will enroll 100 subjects throughout all sites involved in the study.
Patients will be recruited in the office setting after all non-operative modalities for
controlling pain associated with end-stage osteoarthritis of the knee have been
exhausted. Patients will then be presented with the option of total knee replacement.
After patient has agreed to undergo TKA, patients will then be asked (in a face-to-face
setting) if they would like to participate in the study.
Patients will be approached in the office setting after it has been determined that they
have failed conservative management of advanced knee arthritis. Patients will be in the
surgeons' clinic behind closed doors with the performing surgeon and potentially other
members of the research team. Consent will be obtained in the office after scheduling
total knee arthroplasty procedure. The consent process is expected to take 30 minutes,
but more time is available to ensure that patients have all their questions answered
prior to signing the consent form.
Patients will be enrolled in study prior to surgery, outlined above in the consent
process.
On the day of surgery, patients will arrive and will be situated in the pre-operative
holding area. A trained member of the research team will meet the patient in the
pre-operative holding area and will measure the circumference of the patient's leg at the
mid-thigh, mid-knee and mid-calf. The patient's range of motion of the operative leg will
be measured in flexion and extension. All measurements will be recorded in redcap.
The patient will then go on to have their primary total knee arthroplasty by standard of
care procedure. Both cruciate retaining and posterior stabilized total knee replacement
designs will be included in the study. Following closure of the surgical site and
placement of a post-operative occlusive dressing, the operative leg will be measured once
more for circumference and range of motion, and the values will be entered into redcap.
The patient will then be placed in their randomized post-operative sleeve/device and will
be transferred to the PACU and will receive the standard post-operative treatment.
On post-operative day one, patient's will be seen and evaluated in their inpatient rooms.
Their leg measurements will be taken again with the knee sleeve/compressive gradient
dressing pulled down. Patient's skin will be inspected for any reactions to the sleeve
and a standard post-operative examination will be performed to ensure no neurovascular
compromise, blood clots, infections or other post-operative complications.
Patients will likely be discharged on post-operative day 1. Patients that have not been
discharged on post-operative day 1 will not be measured on post-operative day 2.
Patients will be provided with a journal that they will use every daily to track their
pain based on a visual analog scale and their narcotic consumption (number of Percocet or
tramadol pills). Patients will also use their journal to log the number of hours they
wore their sleeve each day. Patients will continue to log the number of pain medications
taken and hours wearing the sleeve for 6 weeks.Sleeves will be worn morning and night removing them only for hygiene and washing of
sleeve for 2 weeks. After 2 weeks, the patient's will wear the sleeve as much as they can
tolerate day and night. At 6 weeks, sleeves will be discontinued all together. Final ROM
and Circumference Measurements will be obtained at 12 weeks post-operative mark.
Patients will be asked to fill out the Knee Society Score questionnaire at the time of
consent and at each post-operative visit.
The Reparel leg sleeve is the experimental device being investigated in this study. It is
intended to improve swelling in the post-operative knee.
Allscripts Electronic Medical Records will be used to collect data about patients during
their inpatient, post-operative stay. UH Care ambulatory EMR and Medent EMR will be used
in the outpatient setting to collect data and track post-operative clinic visits.
The enrollment period will be 1 year from the time of the first patient enrolled in the
study. The enrollment period may be expanded to allow for the investigators to reach
their goal of 100 patients. The total amount of time each patient will be involved in the
study will be 12 weeks. Patients will only be required to wear the post-operative
sleeve/dressing for 6 weeks post-operatively. Patients will continue to record their
narcotic consumption and pain scores for 12 weeks post-operatively.Date to be collected:
Mid-thigh, mid-knee, and mid-calf measurements ROM measurements in knee flexion and knee
extension Visual analog Pain scale Knee society score (KSS) Narcotic consumption Name
Medical record number Surgeon weight.Data Analysis Plan:
Demographics will be reported using descriptives such as count data and percentages.
Differences between groups at baseline (pre-op) will be reported using two-tailed
independent t-tests for continuous variables, and chi-square or Fisher's Exact tests for
categorical data, as appropriate.
The primary outcomes of range of motion, leg circumference, and pain ratings will be
compared post-op between conditions using two-tailed independent t-tests. Should
clinically relevant demographics differ significantly between conditions pre-op
(baseline), post-op comparisons will instead be conducted using one-way ANCOVAs
controlling for differences at pre-op (baseline). These comparisons will additionally be
made at multiple additional time-points throughout a 12-week post-op time period.
A priori power analyses were calculated for two-tailed independent t-tests for each
primary outcome, using an alpha of .05, power = .80. Each of these are reported and the
average of these numbers is used to calculate the final sample size. Clinically
significant reductions in pain are defined as a 2-point change with a standard deviation
of 2.5 using a 10-point scale; 84 patients were estimated. Clinically significant changes
in range of motion are defined as: 10 degrees of difference from a 0-140 degree estimated
range of values. Clinically significant changes in leg circumference are defined as: 1 cm
difference in leg circumference using a 15-30 estimated range of values. To identify
medium effect sizes of .55, 106 patients were estimated. Averaging these values, 99
patients were estimated. To ensure equal numbers of patients in each condition, 100
patients will be recruited for this study.
The data will be monitored every 10 patients to assess for completeness, accuracy and
adherence to the protocol. We will also be monitoring for any obvious safety concerns
that may arise.
There will not be a designated safety team assigned.
