By Jordana Bieze Foster
Less may be more when it comes to knee bracing in some patients with knee osteoarthritis (OA) and patellofemoral pain (PFP), according to studies of soft knee braces presented in May at the 2017 ISPO World Congress in Cape Town, South Africa.
Research from the University of Central Lancashire in the UK analyzed the biomechanical effects of a soft brace in four patients with mild knee OA and 10 controls during a step-down task.
At the knee, use of the soft brace was associated with significant decreases in transverse plane range of motion and transverse plane angular velocity (a measure of the rate of collapse into internal rotation, which reflects patient stability). Interestingly, the soft brace was also associated with a decrease in ankle angular velocity during pronation in the patients with knee OA, along with a decrease in hip internal rotation velocity in the controls.
“Since the brace is not acting mechanically, the only way this is possible is if the brace is affecting neuromuscular control,” said James Richards, PhD, a professor of biomechanics at the University of Central Lancashire in Preston, UK, who presented the findings in Cape Town.
In the knee OA patients, four weeks of soft brace use was also associated with significant improvement in self-reported pain and function assessed using the Knee Osteoarthritis Outcome Score (KOOS).
Richards noted that one patient, an avid golfer, went from needing a motorized golf cart to walking all 18 holes with the use of the soft brace. He cautioned, however, that response to the soft brace varied within the study population, and that categorizing patients into subgroups could help predict response to soft bracing and other knee OA interventions.
Richards and colleagues have been at the forefront of efforts to define subgroups of this type within the PFP population (see “Patellofemoral pain subgroups: A critical first step toward personalized clinical intervention,” January 2017, page 18). And a second ISPO presentation by Richards focused on just one of those PFP subgroups: the “strong” group, which includes most athletes, characterized by patellar hypomobility without hip abductor or quadriceps weakness.
In 20 individuals with PFP who wore a soft knee brace for two weeks, the investigators found significant reductions compared with baseline for peak patellofemoral forces, patellofemoral pressure, patellofemoral loading rate, and peak knee abduction moment during running and cutting. The soft brace was also associated with improvement in KOOS scores for the pain, sport, function, and quality of life subscales.
“Even soft knee bracing can reduce pain and symptoms by reducing patellofemoral joint forces. We’re moderating a change in force with something made of cloth,” Richards said. “This is possible through incremental increases in proprioception and neuromuscular control. Sensory input can affect movement strategy.”
Two other Cape Town presentations examined the extent to which the amount of pressure applied by a soft brace influences its effectiveness.
In 20 healthy individuals, researchers from Jönköping University in Sweden found that although a rigid brace applied more pressure at the knee than a soft brace, the latter was associated with better detection of passive motion.
“High amounts of pressure may in fact compromise proprioception,” said Nerrolyn Ramstrand, PhD, BP&O, an associate professor of prosthetics and orthotics at the university, who presented her group’s findings in Cape Town. “That’s something we haven’t thought about.”
However, in 44 patients with self-reported knee OA, researchers from VU University Medical Center Amsterdam in the Netherlands, found minimal differences between a properly fitted soft brace and one that was one size too large. Compared with no brace, both soft braces were associated with significant improvement in activity limitations, pain, and self-reported knee stability and knee confidence during level and perturbed treadmill walking.
Richards J, Chohan A, Kwaees T, Rawlinson G. Exploring the effects of a non-mechanical knee brace on knee kinematics & kinetics during step descent in healthy individuals & the implications for patients with knee osteoarthritis. Presented at the International Society of Prosthetics & Orthotics World Congress, Cape Town, South Africa, May 2017.
Richards J, Sinclair JK, Selfe J, et al. The effect of knee bracing on pain, symptoms and patellofemoral loading in recreational athletes with patellofemoral pain. Presented at the International Society of Prosthetics & Orthotics World Congress, Cape Town, South Africa, May 2017.
Ramstrand N, Starholm I, Gjøvaag T, Rusaw D. Effects of knee orthosis design on proprioception and balance. Presented at the International Society of Prosthetics & Orthotics World Congress, Cape Town, South Africa, May 2017.
Cudejko T, van der Esch M, van der Leeden M, et al. The immediate effect of a soft brace on pain, activity limitations, self-reported knee instability, and self-reported knee confidence in patients with knee osteoarthritis. Presented at the International Society of Prosthetics & Orthotics World Congress, Cape Town, South Africa, May 2017.