Fig. 1 T2 coronal MRI of a left knee with moderate osteoarthritis, chondral defects, subchondral insufficiency fracture of the medial femoral condyle, and extruded medial meniscus due to meniscal posterior root tear. When, if ever, is knee arthroscopy justified in this case?


Published 11/1/2018
Timothy L. Miller, MD

Knee Arthroscopy and Osteoarthritis: The Numbers Rarely Add Up to 29880

Knee arthroscopy is one of the most commonly performed procedures in orthopaedics. It is a standard practice for academic sports medicine specialists, and it also is a staple among general, community-based orthopaedic surgery practices. However, over the past decade, the utility of arthroscopy for the treatment of patients with knee osteoarthritis (OA) has become increasingly questioned. The indications and benefits of arthroscopy for patients with clinical and radiographic evidence of OA have become so controversial that many insurance carriers have decreased or even eliminated reimbursements for the treatment of pain from degenerative meniscus tears or chondral injuries if more than mild OA is present. This is undoubtedly a concern for orthopaedic surgeons who treat populations who wish to stay active and pain-free without undergoing total knee arthroplasty.

Here, we discuss common questions and guidance on knee arthroscopy and OA.

What are the current guidelines for knee arthroscopy to treat patients with knee OA?

In 2008, the AAOS clinical practice guideline (CPG) on the treatment of OA of the knee recommended against arthroscopy for knee pain when the primary diagnosis is OA. One notable exception to the recommendation that often is cited as an indication for knee arthroscopy is to perform a partial meniscectomy or loose body removal in patients with OA who present with “mechanical signs and symptoms.” The exact definition of mechanical symptoms is unclear and may overlap with OA-related crepitation. By definition, mechanical symptoms include a sensation of catching or locking of the knee joint. Recently, patient-reported mechanical symptoms have been shown to have low reliability and are not universally resolved with knee arthroscopy and partial meniscectomy (Current Procedural Terminology code 29880).

Recent statements by two of the guiding societies in our field make the debate over indications for knee arthroscopy in the arthritic knee somewhat more complex. The 2006 position statement by the Arthroscopy Association of North America on knee OA noted that there is “a subgroup of patients with knee arthritis that can be significantly helped with appropriate arthroscopic surgery.” In 2013, the AAOS appropriate use criteria (AUC) defined knee arthroscopy as an appropriate nonarthroplasty treatment alternative for knee OA. However, at the time, the AUC did not include inflammatory disorders, rheumatoid arthritis, or other general inflammatory arthropathies.

More recently, in 2017, the position statement of the Arthroscopy Association of Canada asserted, “Arthroscopic débridement and/or lavage of the knee joint has not been shown to have any beneficial effect on the natural history of OA, nor are these procedures indicated as a primary treatment in the management of OA of the knee.” The same statement listed 10 situations in which arthroscopy could be employed as an adjunct treatment in patients with known OA, including locked knees, symptomatic loose bodies, and inflammatory arthropathy requiring synovectomy, among others.

Since those statements were published, multiple randomized, controlled trials of patients with clinical and radiographic indications of knee OA have shown that outcomes after arthroscopic débridement, abrasion chondroplasty, and partial meniscectomy are no better than the results of placebo arthroscopic procedures. Other authors from the medical community and the general news media have reported on results suggesting that arthroscopic surgery provides no additional benefits beyond physical therapy (PT), weight management, and medicinal treatments.

Are there any indications in 2018 for knee arthroscopy in the presence of knee OA?

The short answer is yes. With that said, arthroscopy of the arthritic knee still has limited and specific indications, and the indications have evolved greatly over the past five years—they have been narrowed but not eliminated.

Most importantly, patient selection criteria and management of patient expectations are essential. A patient history that includes mechanical symptoms is not a reliable indicator of a treatable intra-articular process that will result in resolution of symptoms with arthroscopic lavage or débridement. In fact, many recent outcome studies have indicated that patients describe mechanical symptoms even after the suspected culprit, such as a meniscus tear or loose body, has been fully addressed arthroscopically. Thus, arthroscopy should be considered with caution for patients with mechanical symptoms and a degenerative meniscus tear or chondral flap tear when joint space narrowing is present or extensive chondral loss is evident on MRI.

Although arthroscopy remains the current standard of care for loose body removal and irrigation of septic arthritis, the greatest expansion of indications for knee arthroscopy in patients with articular cartilage degenerative changes has come with the advocacy of joint preservation. Techniques requiring arthroscopy that were not perfected or approved by the Food and Drug Administration five to 10 years ago are now readily available and demonstrate improved long-term outcomes. Nearly all are specific to an area of isolated cartilage loss or degeneration, rather than diffuse tricompartmental OA. These include but are not limited to medial and lateral meniscal root repair, cartilage restoration procedures like matrix-induced autologous chondrocyte implantation, subchondroplasty and intraosseous bioplasty, arthroscopic-assisted fixation of tibial plateau fractures, and other joint-sparing procedures currently in development.


What do I tell my patients with knee OA who present having already been told they need a knee arthroscopy?

One of the most difficult conversations that many sports medicine orthopaedic surgeons and arthroscopists, like myself, have is with active patients with knee OA. Often, these patients have been referred by a well-intended primary care physician for a knee arthroscopy to treat a degenerative meniscus tear. In many cases, the tear was discovered on an MRI that also revealed notable degenerative joint disease. The degenerative joint disease may have been overlooked or ignored on plain radiographs, or, worse yet, appropriate radiographs (including standing views of the knees) may never have been obtained. Unfortunately, this situation occurs all too commonly and places orthopaedic surgeons in an uncomfortable position.

The key to successfully navigating this potential minefield is honest communication. This situation requires the surgeon to advocate for the patient’s best interest and present realistic expectations of the likely outcome of an arthroscopic procedure. Although it may be difficult to turn down a patient who willingly requests to undergo a relatively straightforward procedure, the temptation to boost work relative value unit numbers is outweighed by a waiting room full of unhappy patients. On the upside, this situation creates a tremendous opportunity to communicate with patients and their families, educate them and their primary care physicians about the condition or injury, and improve patient satisfaction scores over the long run. It is through this type of communication that orthopaedists can also further develop patient-physician relationships, which are often lacking in busy orthopaedic practices.

How do I stay compliant with CPGs and AUC for knee arthroscopy?

In short, knee arthroscopy should be recommended with caution to patients with moderate-to-severe OA, even if there is MRI evidence of a meniscal or chondral tear. With continually mounting evidence that arthroscopy provides minimal, if any, additional benefit to such patients, even when mechanical symptoms are present, orthopaedic surgeons should have specific justifications for performing the procedure and communicate realistic expectations.

In the setting of knee OA, arthroscopy should be reserved for those who have failed extensive nonoperative treatment, including activity modification, anti-inflammatory medications, weight reduction, PT, bracing, and possibly intra-articular injections. Education rather than arthroscopic partial medial and lateral meniscectomy is the answer for this patient population with the risk of continued pain, further degenerative changes, and continued mechanical symptoms, requiring thorough discussion in the preoperative consent.

Timothy L. Miller, MD, is a sports medicine orthopaedic surgeon at The Ohio State University Wexner Medicine Center and Jameson Crane Sports Medicine Institute in Columbus, Ohio.


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