Lateral wedge insoles for medial knee osteoarthritis: 12 month randomised controlled trialBMJ 2011; 342 doi: https://doi.org/10.1136/bmj.d2912 (Published 18 May 2011) Cite this as: BMJ 2011;342:d2912
All rapid responses
This well conducted study concludes that lateral wedge insoles worn
for 12 months provided no symptomatic or structural benefits to patients
with medial compartment osteoarthritis of the knee (MCOA) compared with
flat control insoles.
Given the importance that some researchers place on the knee varus
torque in the progression of MCOA, conservative means to attempt to reduce
this torque by means of an in-shoe lateral wedge constitute a seemingly
logical conservative treatment (Kerrigan et al 2002). However, a
systematic review of lateral wedges (Reilly et al 2006) indicates until
that date there had been no evidence that lateral wedges alone altered the
course of the disease. This is also the view expressed in a clinical
review of osteoarthritis (Hunter and Felson 2006). In addition, a study
(Hurvitz et al 2002) found that the knee adduction moment during gait is
more closely related with static alignment than radiographic disease
severity and in 2006 Maly et al 2006 indicated that the knee adduction
moment is unrelated to the pain, performance and disability associated
Surprisingly, although this study is concerned with applying lateral
wedges to the foot, no mention is made in the introduction to this study
of some recent studies which have noted a biomechanical aspect to MCOA
which concerns the foot.
In 2006 it was noted that patients with MCOA demonstrated a pronated
foot (Reilly et al 2006). This has also been demonstrated in 2010 by
Levinger et al and a further study (Joshi et al 2010) indicates the
possibility of a link between foot pronation, ethnic groups and MCOA.
Gross et al, also in 2010 found that planus foot morphology (pronated
foot) is associated with a moderately increased prevalence of frequent
knee pain and medial tibiofemoral cartilage damage.
Given this new research, it may be that the application of a lateral
wedge to a pronated foot could further compromise the foot and ankle
complex. Surprisingly, this study, in common with the other studies in
the systematic review (Reilly et al 2006) did not publish any details of
foot examination prior to application of an orthotic device. In looking
at the effect of laterally wedged foot orthoses on rearfoot and hip
mechanics it was suggested that a full medical screen of the foot should
occur before laterally wedged foot orthotic devices are prescribed as
they result in an increased rearfoot eversion and inversion moment (Butler
et al 2009). Also, as the normal biomechanics of gait in patients with
MCOA is compromised due to pain and varus deformity, further disruption by
the use of a wedge which may accentuate pronation and retard supination
may provoke degenerative changes even in a previously well balanced foot
and ankle (Friedlander, 1989).
Besides a biomechanical aspect of MCOA there are also work related
and sporting injuries which are associated with its development and in
these cases patients may not display any foot anomalies. Nevertheless, it
would seem to be appropriate to examine the foot before introducing an
orthotic device as the reason for the lack of positive results from the
many trials carried out may be that they are inappropriate for some of the
Butler RJ, Barrios JA, Royer T, Davis IS. Effect of laterally wedged
foot orthoses on rearfoot and hip mechanics in patients with medial knee
osteoarthritis. Prosthetics and Orthotics International, 2009; 33(2): 107
Friedlander GE. Genu Varum and degenerative arthritis of the knee,
questions and answers. Journal of American Medical Association, 1989;
Gross KD, Felson DT, Niu J, Hunter DJ, Guermazi A, Roemer FW, Dufour
AB, Gensure RH, Hannan MT. Flat feet are associated with knee pain and
cartilage damage in older adults. Arthritis Care and Research, 2010; /DOI
Hunter DJ, Felson DT. BMJ 2006; 332(7542) 639-642.
Hurvitz DE, Ryals AB, Case JP, Block JA, Andriacchi TP. The knee
adduction moment during gait in subjects with knee osteoarthritis is more
closely correlated with static alignment than radiographic disease
severity, toe out angle and pain. J Orthop Res, 2002; 20(1): 101-7.
Joshi R, Ganguli N, Carvalho C, de Leon F, Pope J. Varus and valgus
deformities in knee osteoarthritis among different ethnic groups (Indian,
Portuguese and Canadians) within an urban Canadian rheumatology practice.
Indian Journal of Rheumatology, 2010; 5 (4): 180-4.
Kerrigan DC, Lelas JL, Goggins J, Merriman GJ, Kaplan RJ, Felson DT.
Effectiveness of a lateral wedge insole on knee varus torque in patients
with knee osteoarthritis. Archives of Physical Medicine and
Rehabilitation 2002; 83: 889-893.
Levinger P, Menz H B, Footoohabadi MR, Feller JA, Bartlett JR,
Bergman NR. Foot posture in people with medial compartment knee
osteoarthritis. Journal of Foot and Ankle Research, 2010; 3: 29
Maly MR, Costigan PA, Olney SJ Role of knee kinematics and kinetics
on performance and disability in people with medial compartment knee
ateoarthritis. Clin Biomech, 2006; 21: 1051-1059.
Reilly KA, Barker KL, Shamley D. A systematic review of lateral wedge
orthotics - how useful are they in the management of medial compartment
osteoarthritis ? The Knee; 13: 177-183.
Reilly KA, Barker KL, Shamley D, Sandall S. Influence of foot
characteristics on the site of lower limb osteoarthritis. Foot and Ankle
International, 2006; 27: 206-211.
Competing interests: No competing interests