Overview and Rationale
The American Academy of Orthopaedic Surgeons (AAOS), with input from representatives from the American Orthopaedic Society for Sports Medicine, the American Association for Hip and Knee Surgeons, The Knee Society, the American Academy of Family Physicians, the American Physical Therapy Association, the Arthroscopic Association of North America, the International Cartilage Repair Society, the American Medical Society for Sports Medicine, and the American Society of Regional Anesthesia and Pain, recently published their clinical practice guideline (CPG), Management of Osteoarthritis of the Knee (nonarthroplasty), third edition.1 This CPG was approved by the AAOS Board of Directors in August 2021. The purpose of this CPG is to assist physicians, surgeons, and other healthcare professionals who care for patients with osteoarthritis of the knee in making treatment decisions that improve the quality and efficacy of care.
Osteoarthritis (of any joint) was the primary diagnosis for 23.7 million ambulatory care visits in 2013. An estimated 32.5 million adults in the US, 14% of the American population, suffered from symptomatic knee osteoarthritis between 2008 and 2014. The incidence of knee osteoarthritis in the United States is estimated at 240 persons per 100,000 per year. Worldwide prevalence of radiographically confirmed symptomatic knee osteoarthritis (OA) is estimated to be 3.8% overall, increasing with age to more than 10% in the population older than 60 years.
Risk factors of the condition increase with age, especially in women. Although women represent 51% of the general population in the United States, they represent 78% of the patients diagnosed with osteoarthritis between 2008 and 2014. Genetics and hereditary vulnerability, elevated body mass, certain occupations, and traumatic knee injuries are other factors that increase one's risk of developing the disease.
Individuals with osteoarthritis of the knee often complain of joint pain, stiffness, and difficulty with purposeful movement. Older adults with self-reported osteoarthritis visit their physicians more frequently and experience greater functional limitations than others in the same age group. The goal of the treatment is to provide pain relief and improve the patient's functioning. Most interventions are associated with some potential for adverse outcomes, especially if invasive or surgical. Because the clinical research usually does not differentiate between the sexes, it is possible that future research may result in a better understanding of how a patient's sex alters treatment benefits and harms.
Therefore, the AAOS developed an evidence-based CPG to aid practitioners in the treatment of patients with symptomatic osteoarthritis of the knee.1 Furthermore, the CPG represents a call for continued research to better understand the optimal indications for and the utility of treatment options for osteoarthritis of the knee before knee arthroplasty, especially efforts to establish efficacy within specific subgroups and to identify factors that could discriminate between responders and nonresponders for specific treatments. An exhaustive literature search was conducted resulting initially in more than 2,400 papers for full-text review. The papers were then graded for quality and determined whether the publication aligned with the patients, interventions, and outcomes of concern. For CPG PICO (ie, population, intervention, comparison, and outcome) questions that returned no evidence from the systematic literature review, the work group used the established AAOS CPG methodology to generate two companion consensus statements for alternative nonsurgical treatments, surgical treatments on the effectiveness of dry needling, and the use of free-floating interpositional devices in the management of symptomatic osteoarthritis of the knee.
In summary, the AAOS Management of Osteoarthritis of the Knee (nonarthroplasty) CPG involved reviewing more than 14,400 abstracts and more than 2,400 full-text articles to develop 27 recommendations supported by 617 research articles meeting stringent inclusion criteria. Each recommendation is based on a systematic review of the research related topic, which resulted in eight recommendations classified as high, eight recommendations classified as moderate, and 11 as limited. The strength of recommendation is assigned based on the quality of the supporting evidence. The strength of recommendation also takes into account the quality, quantity, trade-offs between the benefits and harms of a treatment, and magnitude of a treatment's effect.
Guideline Summary
Dietary supplements have long been seen as an alternative to medications for the symptomatic management of knee osteoarthritis. The current guidelines focused on the evaluation of glucosamine, chondroitin, turmeric, ginger extract, and vitamin D. Most of the evidence demonstrated either some improvement or no change in patient outcomes for those with osteoarthritis of the knee. Although the evidence does not consistently demonstrate a benefit to dietary supplements, the risks involved are relatively minimal with the primary barrier being expense because dietary supplements are typically an out-of-pocket expense to patients. The lack of reproducibility in the evidence and the variability between dietary supplement manufactures with limited oversight by the United States Food and Drug Administration continues to limit the strength of the recommendation and hinder future research.
Oral nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen have been widely adopted in the treatment of knee osteoarthritis. The evidence would support the use of NSAIDs and acetaminophen because these oral medications consistently demonstrate improved pain and function in patients with knee osteoarthritis. For nonselective and selective cyclooxygenase-2 oral NSAIDs, both are effective medications. Although selective cyclooxygenase-2 oral NSAIDs were developed to reduce gastrointestinal adverse events, we found no notable difference in the risk of a gastrointestinal adverse event with nonselective NSAIDs. Despite the effectiveness of acetaminophen and NSAIDs, it is important to understand the appropriate prescribing for the medications because each medication carries a black box warning from the FDA. Finally, oral narcotics (including tramadol) should not be used in the treatment of knee osteoarthritis because of the notable increase in medication-related adverse effects with no consistent improvement in pain and function.
Intra-articular injections are widely used by patients, with the most common injections being corticosteroid, hyaluronic acid, and platelet-rich plasma. Controversy exists over the effectiveness of each intra-articular injection. Among the options for intra-articular injections, corticosteroid had considerable evidence with 19 high-quality and six moderate-quality studies supporting the use of intra-articular corticosteroid, although the duration of benefits was often only 3 months. Platelet-rich plasma is an alternative with two high-quality studies and one moderate-quality study supporting reduced pain and improved function in patients with knee osteoarthritis; however, the evidence demonstrated inconsistency with a worse treatment response in patients with severe knee osteoarthritis. In addition, concerns have been raised for platelet-rich plasma regarding the cost and safety profile. Although intra-articular hyaluronic acid is commonly used to treat knee osteoarthritis, it was not consistently supported by the 17 high-quality and 11 moderate-quality studies. The recommendation does recognize the potential for hyaluronic acid to benefit patients as the calculated number needed to treat was 17 patients; however, the current evidence does not identify the subset of patients who benefit from hyaluronic acid to explain the observed inconsistency in the evidence. As a result, the recommendation was against the routine use of hyaluronic acid in patients with knee osteoarthritis.
Sustained weight loss has been shown to benefit pain and, to a lesser extent, function in overweight and obese patients with knee osteoarthritis. Although there is some evidence that exercise may be better than diet to achieve this weight loss,2,3 the preferred approach is to use diet and exercise.4,5 There is no risk or downside to sustained weight loss and obvious other health benefits. Patients may not always be motivated and even when they are; it can be challenging to achieve and maintain meaningful weight loss. Despite this challenge, there is little controversy regarding this recommendation. There is a need for larger, randomized clinical trials, particularly studies focused on function and quality of life in patients with knee osteoarthritis and the cost-effectiveness of weight loss interventions.
Exercise and physical therapy are excellent modalities to address pain and function in patients with knee osteoarthritis. There is strong evidence that exercise, including unsupervised, supervised, and aquatic, improve pain and function in these patients. Studies do not establish a clear benefit from supervised exercise compared with unsupervised exercise.6–9 Similarly, it is not clear that aquatic exercise is better than land-based exercise in patients with knee osteoarthritis, although one study reported that patients treated with aquatic exercise had less pain with walking than patients treated with land-based exercise.10 Adding neuromuscular training programs may improve function and/or walking speed but does not reduce pain compared with exercise and may cause a temporary increase in knee pain or muscle soreness.11–15 Supervised and aquatic exercise, as well as neuromuscular training programs, may have cost and access challenges, especially compared with unsupervised exercise programs.
Meniscus tears in patients with knee osteoarthritis are a particularly challenging clinical complication. For the majority of patients with knee osteoarthritis, particularly with more advanced osteoarthritis, the meniscus tear is a result of the degenerative process rather than an independent cause of clinical symptoms. These patients are unlikely to get much, if any, improvement from the surgical treatment of the meniscus tear. Contrarily, a small number of truly obstructing displaced meniscus tears are a primary cause of predominantly mechanical symptoms and warrant treatment for that reason. In a subset of patients with mild-to-moderate knee osteoarthritis, meniscal tears may be a notable contributor to patient symptoms. These are the patients who may be candidates for arthroscopic partial meniscectomy after failing nonsurgical treatment, such as physical therapy, corticosteroid or other intra-articular injections, or other modalities. If symptoms do not respond to these treatments, arthroscopic partial meniscectomy is an appropriate and effective treatment, with a substantial percentage of patients randomized to nonsurgical treatment who cross over in published trials.16,17 There does not seem to be any negative effect of trying nonsurgical treatment before undergoing arthroscopic partial meniscectomy.
In summary, this guideline summarizes the best recommendations the work group felt were possible on the basis of the current published evidence for the nonarthroplasty treatment of knee osteoarthritis. The recommendations herein are just that—they are intended as principles of treatment rather than prescriptive, as if correct or ideal for every patient irrespective of disease severity, location in the joint, and symptoms. As per any evidence-based recommendation, the physician team should also rely on their own clinical judgment, experience, available resources, and desires of their patients and patients' families. Furthermore, these recommendations were limited in some areas, as noted herein, based on low quality or inadequate evidence, and highlight areas requiring diligent future study and investigation. Our hope is that these recommendations will serve as a useful template for both clinical and shared decision-making with patients and patients' families affected by knee osteoarthritis and that future research will permit revision, refinement, improvement, and expansion of these recommendations toward this worthy end. These efforts can then further serve to help guide our nonarthroplasty treatment of patients with knee osteoarthritis toward the goal of providing each patient with both the best treatment options and the best outcome for their specific clinical manifestation of the disease.
Recommendations
This summary of recommendations of the AAOS Management of Osteoarthritis of the Knee (nonarthroplasty) Evidence-Based CPG contains a list of evidence-based treatment recommendations. Discussions of how each recommendation was developed and the complete evidence report are contained in the full guideline at http://www.aaos.org/oak3cpg. 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.
The 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.
A strong recommendation means that the quality of the supporting evidence is high. 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. A limited recommendation means that there is a lack of compelling evidence that has resulted in an unclear balance between benefits and potential harm. A consensus recommendation means that expert opinion supports the guideline recommendation although there is no available empirical evidence that meets the inclusion criteria of the guideline's systematic review.
Strength of Recommendations Descriptions
-
| Strength of Recommendation | Overall Strength of Evidence | Description of Evidence Quality | Strength Visual |
| Strong | Strong | Evidence from two or more “High” quality studies with consistent findings for recommending for or against the intervention. Also requires no reasons to downgrade from the EtD framework |  |
| Moderate | Moderate or Strong | Evidence from two or more “Moderate” quality studies with consistent findings or evidence from a single “High” quality study for recommending for or against the intervention. Also requires no or only minor concerns addressed in the EtD framework. |  |
| Limited | Limited, Moderate, or Strong | Evidence from one or more “Low” quality studies with consistent findings or evidence from a single “Moderate” quality study recommending for or against the intervention. In addition, higher strength evidence can be downgraded to limited because of major concerns addressed in the EtD framework. |  |
| Consensus | No reliable evidence | There is no supporting evidence, or higher quality evidence was downgraded because of major concerns addressed in the EtD framework. In the absence of reliable evidence, the guideline work group is making a recommendation based on their clinical opinion. |  |
EtD = Evidence-to-Decision
Lateral Wedge Insoles
Lateral wedge insoles are not recommended for patients with knee osteoarthritis.
Strength of recommendation: Strong.
Implication: Practitioners should follow a Strong recommendation unless a clear and compelling rationale for an alternative approach is present.
Canes
Canes could be used to improve pain and function in patients with knee osteoarthritis.
Strength of recommendation: Moderate.
Implication: Practitioners should generally follow a Moderate recommendation but remain alert to new information and be sensitive to patient preferences.
Braces
Brace treatment could be used to improve function, pain, and quality of life in patients with knee osteoarthritis.
Strength of recommendation: Moderate. (downgrade)
Implication: Practitioners should generally follow a Moderate recommendation but remain alert to new information and be sensitive to patient preferences.
Oral/Dietary Supplements
The following supplements may be helpful in reducing pain and improving function for patients with mild-to-moderate knee osteoarthritis; however, the evidence is inconsistent/limited, and additional research clarifying the efficacy of each supplement is needed.
- • Turmeric
- • Ginger extract
- • Glucosamine
- • Chondroitin
- • Vitamin D
Strength of recommendation: Limited. (downgrade)
Implication: Practitioners should feel little constraint in following a recommendation labeled Limited, 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.
Topical Treatments
Topical NSAIDs should be used to improve function and quality of life for the treatment of osteoarthritis of the knee, when not contraindicated.
Strength of recommendation: Strong.
Implication: Practitioners should follow a Strong recommendation unless a clear and compelling rationale for an alternative approach is present.
Supervised Exercise
Supervised exercise, unsupervised exercise, and/or aquatic exercise are recommended over no exercise to improve pain and function for the treatment of knee osteoarthritis.
Strength of recommendation: Strong.
Implication: Practitioners should follow a Strong recommendation unless a clear and compelling rationale for an alternative approach is present.
Neuromuscular Training
Neuromuscular training (ie, balance, agility, and coordination) programs in combination with exercise could be used to improve performance-based function and walking speed for the treatment of knee osteoarthritis.
Strength of recommendation: Moderate. (downgrade)
Implication: Practitioners should generally follow a Moderate recommendation but remain alert to new information and be sensitive to patient preferences.
Self-Management
Patient education programs are recommended to improve pain in patients with knee osteoarthritis.
Strength of recommendation: Strong.
Implication: Practitioners should follow a Strong recommendation unless a clear and compelling rationale for an alternative approach is present.
Patient Education
Patient education programs are recommended to improve pain in patients with knee osteoarthritis.
Strength of recommendation: Strong.
Implication: Practitioners should follow a Strong recommendation unless a clear and compelling rationale for an alternative approach is present.
Weight Loss Intervention
Sustained weight loss is recommended to improve pain and function in overweight and obese patients with knee osteoarthritis.
Strength of recommendation: Moderate. (downgrade)
Implication: Practitioners should generally follow a Moderate recommendation but remain alert to new information and be sensitive to patient preferences.
Manual Therapy
Manual therapy in addition to an exercise program may be used to improve pain and function in patients with knee osteoarthritis.
Strength of recommendation: Limited.
Implication: Practitioners should feel little constraint in following a recommendation labeled Limited, 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.
Massage
Massage may be used in addition to usual care to improve pain and function in patients with knee osteoarthritis.
Strength of recommendation: Limited. (downgrade)
Implication: Practitioners should feel little constraint in following a recommendation labeled Limited, 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.
Laser Treatment
FDA-approved laser treatment may be used to improve pain and function in patients with knee osteoarthritis.
Strength of recommendation: Limited. (downgrade)
Implication: Practitioners should feel little constraint in following a recommendation labeled Limited, 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.
Acupuncture
Acupuncture may improve pain and function in patients with knee osteoarthritis.
Strength of recommendation: Limited. (downgrade)
Implication: Practitioners should feel little constraint in following a recommendation labeled Limited, 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.
Transcutaneous Electrical Nerve Stimulation
Modalities that may be used to improve pain and/or function in patients with knee osteoarthritis include
- a. Transcutaneous electrical nerve stimulation (pain)
Strength of recommendation: Limited. (downgrade)
Implication: Practitioners should feel little constraint in following a recommendation labeled Limited, 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.
Percutaneous Electrical Nerve Stimulation/Pulsed Electromagnetic Field Therapy
Modalities that may be used to improve pain and/or function in patients with knee osteoarthritis include
- a. Percutaneous electrical nerve stimulation (pain and function)
- b. Pulsed electromagnetic field (pain)
Strength of recommendation: Limited. (downgrade)
Implication: Practitioners should feel little constraint in following a recommendation labeled Limited, 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.
Extracorporeal Shockwave Therapy
Extracorporeal shockwave therapy may be used to improve pain and function for the treatment of osteoarthritis of the knee.
Strength of recommendation: Limited. (downgrade)
Implication: Practitioners should feel little constraint in following a recommendation labeled Limited, 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.
Oral NSAIDs
Oral NSAIDs are recommended to improve pain and function in the treatment of knee osteoarthritis when not contraindicated.
Strength of recommendation: Strong.
Implication: Practitioners should follow a strong recommendation unless a clear and compelling rationale for an alternative approach is present.
Oral Acetaminophen
Oral acetaminophen is recommended to improve pain and functions.
Strength of recommendation: Strong.
Implication: Practitioners should follow a strong recommendation unless a clear and compelling rationale for an alternative approach is present.
Oral Narcotics
Oral narcotics, including tramadol, result in a notable increase of adverse events and are not effective at improving pain or function for the treatment of osteoarthritis of the knee.
Strength of recommendation: Strong.
Implication: Practitioners should follow a strong recommendation unless a clear and compelling rationale for an alternative approach is present.
Hyaluronic Acid
Hyaluronic acid intra-articular injection(s) is not recommended for routine use in the treatment of symptomatic osteoarthritis of the knee.
Strength of recommendation: Moderate. (downgrade)
Implication: Practitioners should generally follow a moderate recommendation but remain alert to new information and be sensitive to patient preferences.
Intra-articular Corticosteroids
Intra-articular corticosteroids could provide short-term relief for patients with symptomatic osteoarthritis of the knee.
Strength of recommendation: Moderate. (downgrade)
Implication: Practitioners should generally follow a moderate recommendation but remain alert to new information and be sensitive to patient preferences.
Platelet-rich Plasma
Platelet-rich plasma may reduce pain and improve function in patients with symptomatic osteoarthritis of the knee.
Strength of recommendation: Limited. (downgrade)
Implication: Practitioners should feel little constraint in following a recommendation labeled Limited, 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.
Denervation Therapy
Denervation therapy may reduce pain and improve function in patients with symptomatic osteoarthritis of the knee.
Strength of recommendation: Limited. (downgrade)
Implication: Practitioners should feel little constraint in following a recommendation labeled Limited, 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.
Lavage/Débridement
Arthroscopy with lavage and/or débridement in patients with a primary diagnosis of knee osteoarthritis is not recommended.
Strength of recommendation: Moderate.
Implication: Practitioners should generally follow a Moderate recommendation but remain alert to new information and be sensitive to patient preferences.
Partial Meniscectomy
Arthroscopic partial meniscectomy can be used for the treatment of meniscal tears in patients with concomitant mild-to-moderate osteoarthritis who have failed physical therapy or other nonsurgical treatments.
Strength of recommendation: Moderate.
Implication: Practitioners should generally follow a Moderate recommendation but remain alert to new information and be sensitive to patient preferences.
Tibial Osteotomy
High tibial osteotomy may be considered to improve pain and function in properly indicated patients with unicompartmental knee osteoarthritis.
Strength of recommendation: Limited. (downgrade)
Implication: Practitioners should feel little constraint in following a recommendation labeled Limited, 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.
Dr. Needling
In the absence of reliable evidence, it is the opinion of the work group that the utility/efficacy of dry needling is unclear and requires additional evidence.
Strength of recommendation: Consensus
Implication: In the absence of reliable evidence, practitioners should remain alert to new information because emerging studies may change this recommendation. Practitioners should weigh this recommendation with their clinical expertise and be sensitive to patient preferences.
Free-Floating Interpositional Devices
In the absence of reliable or new evidence, it is the opinion of the work group not to use free-floating (unfixed) interpositional devices in patients with symptomatic medial compartment osteoarthritis of the knee.
Strength of recommendation: Concensus
Implication: In the absence of reliable evidence, practitioners should remain alert to new information because emerging studies may change this recommendation. Practitioners should weigh this recommendation with their clinical expertise and be sensitive to patient preferences.
