Methods

After we received Institutional Review Board approval, we asked all active members of the American Association of Hip and Knee Surgeons (AAHKS) to complete an anonymous questionnaire designed to elicit the current treatment preferences of arthroplasty surgeons. The questionnaire included five clinical vignettes based on the radiographic system for classification of knee OA described by Kellgren and Lawrence^[3] (Table 2). Participants were contacted by email in June 2016 to complete the questionnaire via the Google Forms survey platform. We obtained official sponsorship from the AAHKS Health Policy and Research Committee, whose members collaborated with us on the questionnaire design and distributed the survey. We used human-participant regulations to develop, distribute, and manage the data to ensure confidentiality of the AAHKS members' information. No data collected could be used to identify individual AAHKS members, and the AAHKS Health Policy and Research Committee maintained the email Listserv separate from the authors' and the survey databases.

We determined the frequency of use of the recommended interventions for each stage of pathology and for all the clinical vignettes combined. The observed proportion of agreement was determined to evaluate agreement among respondents for the individual vignettes. We calculated the Fleiss κ coefficient to assess agreement for all vignettes combined.^[4] A κ coefficient of <0.4 was designated as poor, 0.4 to 0.75 as fair, and >0.75 as excellent.

Results

Of 345 physicians who completed the survey, 94.8% indicated "operative, joints" as their self-selected subspecialty (Table 3). The frequency of use of AAOS recommended interventions was 80%, 82%, 21%, 50%, and 98% for OA stages zero through 4, respectively. For OA stages 2 and 3, intra-articular (IA) hyaluronic acid was the most commonly selected intervention. This intervention is not currently recommended by the AAOS. The vignette depicting stage 4 OA demonstrated the highest proportion of agreement (for use of total knee arthroplasty [TKA]) with AAOS guidelines, whereas the stage 3 OA vignette demonstrated the lowest proportion of agreement (for use of IA corticosteroids) with AAOS guidelines (Table 4). The Fleiss κ coefficient for overall agreement was 0.31. The three most commonly selected modalities for all vignettes combined were strengthening exercises with neuromuscular education (410 responses), TKA (391 responses), and IA corticosteroids (349 responses).

Discussion

Since the release of the first set of guidelines in 2008, the AAOS has devoted effort, time, and resources to provide the orthopaedic community with tools for clinical decision making.^[1] To our knowledge, ours is the first investigation of orthopaedic surgeons' compliance with the evidence-based clinical practice guidelines for treating OA of the knee. On the basis of our findings, it appears that the current practice of orthopaedic surgeons is not in line with AAOS recommendations for treatment of moderate to severe OA, given the respondents' excessive use of IA injections. The AAOS guidelines recommend neither for nor against use of IA corticosteroids, and the guidelines strongly recommend against the use of hyaluronic acid. Although additional studies are needed to clarify the role of IA corticosteroids in treating knee OA, it appears that the AAOS guidelines have not effectively reached the orthopaedic community, resulting in continued use of a therapeutic modality with no proven benefit to the patient. To improve treatment consensus and patient outcomes, we encourage greater dissemination of the AAOS evidence-based guidelines and improved education of the orthopaedic community.

To the best of our knowledge, four level I clinical trials were used to evaluate the role of IA corticosteroids and to compile the AAOS recommendations on the nonsurgical treatment of knee OA. Chao et al^[5] and Raynauld et al^[6]reported improved outcomes after the use of IA corticosteroids compared with placebo for the treatment of symptomatic OA. In contrast, Caborn et al^[7] and Arden et al^[8] reported worse outcomes after the use of IA corticosteroids compared with the use of IA hyaluronic acid and tidal irrigation, respectively; neither of these interventions has been found to improve outcomes for patients with symptomatic knee OA.

Cochrane Musculoskeletal Group researchers evaluated the use of IA corticosteroids in a meta-analysis of the literature on the subject published up to February 2015.^[9] Their inconclusive findings paralleled those published by the AAOS. A 2016 study investigated the use of IA corticosteroids and IA hyaluronic acid among Medicare patients with knee OA.^[10] The authors of the study cautioned that these modalities were being used in excess of what is supported in the literature; however, this study did not provide any context for this finding regarding OA severity.^[10]

Evidence is increasing that IA corticosteroids may increase perioperative risks. Bedard et al^[11] investigated outcomes of 29,603 patients with symptomatic OA and found that those treated with IA corticosteroids within 7 months of undergoing TKA were more likely to develop a postoperative infection than those treated >7 months prior to surgery. This finding has important implications for the patient with imminent TKA because delayed surgical intervention for knee OA can have detrimental effects on outcomes. Given the frequency of IA corticosteroid use and the size of the patient population with moderate to severe OA of the knee, it is important to prioritize identification of the role and timing of this modality through performance of additional clinical trials.

Although the AAOS guidelines cannot recommend for or against the use of IA corticosteroids, the guidelines provide valuable direction regarding the use of IA hyaluronic acid for symptomatic OA of the knee. Although investigators in multiple clinical trials have reported positive outcomes for this modality using various scoring systems (eg, the Western Ontario and McMaster Universities Arthritis Index, visual analog scale), clinically important improvement was absent when evaluating outcomes in the context of the minimally important difference criteria.^[1,12–14] Given the lack of perceptible clinical improvement, IA hyaluronic acid is not recommended for symptomatic OA of the knee. However, frequent use of IA hyaluronic acid for moderate to severe OA was reported. Given the disparity between the recommendations and actual practice, the orthopaedic community needs education regarding the efficacy this modality.

Historically, IA injections were used most frequently to treat patients with moderate to severe OA of the knee who were poor surgical candidates or below the threshold for surgical intervention.^[10] Given the unclear role of IA corticosteroids and the negligible benefit of IA hyaluronic acid, treating patients with moderate to severe OA has become difficult. Although developing new therapies for this patient population is encouraged, equal emphasis should be placed on identifying the optimal dose, regimen, and timing of currently recommended modalities, including NSAIDs, strengthening exercises along with neuromuscular education, and TKA.^[15–19]

One potential limitation of our study was our requirement that respondents select one therapeutic modality per vignette. This restriction was designed to emphasize the clinician's primary treatment preference; however, it is not representative of clinical practice. Allowing respondents to choose multiple modalities may have increased the observed agreement with AAOS guidelines for treatment of knee OA. In addition, our findings were unable to account for the potential influence of patients' requests on physicians' preferences. Patient requests likely influence choice of therapy and subsequent trends. Finally, four of the authors were fellows of the AAOS when this study was conducted; however, none held a position on the AAOS clinical practice guidelines advisory board.

Conclusions

Management of moderate to severe OA of the knee does not align with AAOS guidelines on management of this condition. These AAOS recommendations apparently have not effectively reached the orthopaedic community, resulting in continued use of hyaluronic acid. Future clinical trials are required to identify the role of IA corticosteroids in managing this condition. In addition, improved dissemination of the evidence-based practice guidelines and education of the orthopaedic community may help to increase consensus within the field and improve patient outcomes through use of the AAOS evidence-based clinical practice guidelines.