Treatment of Osteoarthritis of the Knee, 2nd edition
This summary of the AAOS clinical practice guideline, “Treatment of Osteoarthritis of the
Knee” 2nd edition, contains a list of the evidence based treatment recommendations and includes
only less invasive alternatives to knee replacement. Discussion of how each recommendation
was developed and the complete evidence report are contained in the full guideline at
www.aaos.org/guidelines. Readers are urged to consult the full guideline for the comprehensive
evaluation of the available scientific studies. The recommendations were established using
methods of evidence-based medicine that rigorously control for bias, enhance transparency, and
promote reproducibility.
This summary of recommendations is not intended to stand alone. Medical care should be based
on evidence, a physician’s expert judgment and the patient’s circumstances, values, preferences
and rights. For treatment procedures to provide benefit, mutual collaboration with shared
decision-making between patient and physician/allied healthcare provider is essential.
Conservative Treatments: Recommendations 1-6
We recommend that patients with symptomatic osteoarthritis of the knee participate in selfmanagement
programs, strengthening, low-impact aerobic exercises, and neuromuscular
education; and engage in physical activity consistent with national guidelines.
Strength of Recommendation: Strong
Description: Evidence is based on two or more “High” strength studies with consistent findings for recommending
for or against the intervention. A Strong recommendation means that the benefits of the recommended approach
clearly exceed the potential harm and/or that the quality of the supporting evidence is high.
Implications: Practitioners should follow a Strong recommendation unless a clear and compelling rationale for an
alternative approach is present.
This recommendation is rated strong because of seven high-strength studies of which five
showed beneficial outcomes. The exercise interventions were predominantly conducted under
supervision, most often by a physical therapist. The self-management interventions were led by
various healthcare providers including rheumatologists, nurses, physical and occupational
therapists, and health educators. The evidence supports the use of self-management programs
in primary care patients with knee osteoarthritis. One of the studies used an existing evidencebased
program, the Arthritis Self-Management Program (ASMP), which was modified to
include an exercise component.20
In a high-strength study by Coleman et al.,21 patients in a 6-
week self-management program demonstrated statistically significant and possibly minimum
clinically important improvements in WOMAC Pain, Stiffness, Function, and Total scores at
eight weeks as compared to wait-listed controls. The program in that study was based on the
same theoretical framework as the ASMP, but included content that was specifically tailored to
patients with knee osteoarthritis.
Studies in this review reported improvements in 29 of 37 outcomes favoring strength training
over a control (usual care, education, or no treatment). Statistically significant and clinically
important improvements were reported for VAS Pain, WOMAC Pain, and WOMAC Function
In addition, 7 of 23 outcomes indicated statistically significant improvements with strengthening
exercises, when performed as part of a physical therapy treatment program, versus control. 22-24
Three of the seven outcomes were clinically significant and one was possibly clinically
significant. One study reported statistically significant and possibly clinically significant
improvement in WOMAC Total score following a combination of knee exercise and manual
physical therapy as compared to subtherapeutic ultrasound (control).25
Studies also addressed the type and setting for strength training. Long-term outcomes did not
vary among isometric, isotonic, or isokinetic exercises.26 Both weight-bearing and nonweightbearing
exercises were superior to control in improving physical function, however, the results
were conflicting when the exercises were compared to each other.27 High-resistance strength
training led to significantly faster walk times on spongy surfaces as compared to lowresistance
training28. Ebnezar et al.29-31 compared a combination of yoga and physical therapy
to physical therapy alone. All eight outcomes were statistically and clinically significant
favoring the combined treatment group measured by WOMAC Function and the SF-36
Physical Function and Bodily Pain subscales. Aquatic therapy was also deemed a suitable
alternative to land-based strengthening exercises.32 Of the three studies that investigated
exercise in the home setting, the highest strength study favored home exercise versus no
exercise in reducing patients’ global pain rating; however, this finding did not meet the
minimum clinically important improvement threshold.33
Three studies the effects of aerobic walking versus health education and one compared it to usual
care in adults with osteoarthritis of the knee. There were statistically significant improvements
with aerobic exercise in all but one of the performance-based functional tasks as compared to the
education group. In the study by Kovar et al.,34 favorable outcomes were reported by the
supervised walking group rather than usual care with statistically significant improvements in 6-
minute walking distance and the Arthritis Impact Measurement Scale (AIMS) Physical Activity
and Pain subscales.
For neuromuscular education, three of four outcomes were statistically significant favoring
combined kinesthesia, balance, and strength training exercises versus strength training alone. A
high-strength study by Fitzgerald et al.35 applied an effective treatment for anterior cruciate
ligament injury to patients with osteoarthritis of the knee; they found that standard exercise
combined with agility and perturbation therapy was not more effective than standard exercise
therapy alone. Five of five outcomes were statistically significant for proprioception training.
Lin et al.36 randomized 108 patients to nonweight-bearing proprioception training, nonweightbearing
strength training, and non treatment groups. Both proprioception and strength training
were significantly more effective in improving WOMAC Pain and Function scores than no
A number of fitness-related organizations have disseminated guidelines for physical activity.
They generally emphasize the importance of aerobic conditioning and muscle- and bonestrengthening,
regular activity, and balance exercises for older adults. In 2008, the federal
government for the first time published national guidelines. Here is the link to the US
Department of Health and Human Service’s physical activity guidelines:
We suggest weight loss for patients with symptomatic osteoarthritis of the knee and a BMI ≥ 25.
Strength of Recommendation: Moderate
Description: Evidence from two or more “Moderate” strength studies with consistent findings, or evidence from a
single “High” quality study for recommending for or against the intervention. A Moderate recommendation means
that the benefits exceed the potential harm (or that the potential harm clearly exceeds the benefits in the case of a
negative recommendation), but the quality/applicability of the supporting evidence is not as strong.
Implications: Practitioners should generally follow a Moderate recommendation but remain alert to new
information and be sensitive to patient preferences.
There was one moderate- and two low- strength studies included in this recommendation.
Physical Function on the SF-36 showed minimum clinically important improvement in outcomes
for this patient population. WOMAC function also showed statistical improvement which was
possibly clinically significant. Diet and exercise combined revealed improved results. The
workgroup considers that the public and patient health benefits of weight loss warranted an
upgrade of the recommendation strength to moderate. 53-55
We cannot recommend using acupuncture in patients with symptomatic osteoarthritis of the
Strength of Recommendation: Strong
Description: Evidence is based on two or more “High” strength studies with consistent findings for recommending
for or against the intervention. A Strong recommendation means that the quality of the supporting evidence is high.
A harms analysis on this recommendation was not performed.
Implications: Practitioners should follow a Strong recommendation unless a clear and compelling rationale for an
alternative approach is present.
There were five high- and five moderate- strength studies that compared acupuncture to
comparison groups receiving non-intervention sham, usual care, or education. The five
moderate-strength studies were included because they reported outcomes that were different than
the high-strength evidence. High-strength studies included: Berman et al, 61 Suarez-Almazor et
al.,62 Weiner et al.,63 Williamson et al.64 and Taechaarpornkul et al.65 Moderate-strength studies
included: Sandgee et al.,66 Vas et al.,67 Witt et al.68 and Berman et al.69 The majority of studies
were not statistically significant and an even larger proportion of the evidence was not clinically
significant. Some outcomes were associated with clinical- but not statistical- significance. The
strength of this recommendation was based on lack of efficacy, not on potential harm.
We are unable to recommend for or against the use of physical agents (including
electrotherapeutic modalities) in patients with symptomatic osteoarthritis of the knee.
Strength of Recommendation: Inconclusive
Description: Evidence from a single low quality study or conflicting findings that do not allow a recommendation
for or against the intervention. An Inconclusive recommendation means that there is a lack of compelling evidence
that has resulted in an unclear balance between benefits and potential harm.
Implications: Practitioners should feel little constraint in following a recommendation labeled as Inconclusive,
exercise clinical judgment, and be alert for emerging evidence that clarifies or helps to determine the balance
between benefits and potential harm. Patient preference should have a substantial influencing role.
The evidence was mixed regarding the efficacy of physical agents and electrotherapeutic
modalities because of contradiction in findings, design flaws, or a low count of like studies. A
single low-strength70 and a single-moderate strength study71comparing pulsed electrical
stimulation to placebo produced contradictory results. See the results of the Fary et al.70 and
Zizic et al.71 articles i