Degenerative joint disease of the knee is among the most common orthopedic conditions requiring treatment today. The breakdown of articular cartilage of the knee may present with symptomatic pain, swelling, and associated disability in both activities of daily living and recreation. The population at risk to develop osteoarthritis of the knee continues to grow rapidly with aging of the baby boomer generation, the obesity epidemic, and the increase in athletic injuries particularly among females during the past 2 decades.¹

Unfortunately, as prevalent and disabling as knee arthritis is recognized to be, no specific medical or surgical remedy has effectively altered the natural history. Despite improvements in surgical procedures to repair or regenerate articular cartilage of the knee, these are largely focused on isolated cartilage lesions, rather than generalized degenerative changes of the knee. As in the past, the treatment strategies today continue to concentrate primarily on pain control and improvement in a patient’s quality of life.

The pain associated with osteoarthritis of the knee is typically managed with nonsurgical treatments including activity modification, strengthening knee exercises, nonsteroidal anti-inflammatory medications, braces, and ambulatory aids. Much effort has been directed at intra-articular injections such as corticosteroids and a variety of hyaluronic acid derivatives.² Recently, biologic therapies such as platelet-rich plasma and bone marrow are receiving a great deal of attention with varied results.³,⁴,⁵,⁶ Depending on severity and location, a variety of surgical options exist including femoral or tibial osteotomies, partial and total knee replacement. This chapter will focus on arthroscopic techniques designed to treat knee arthritis. Review of the published literature on these techniques over the past 2 decades has demonstrated more limited indications for arthroscopy for these patients. This has coincided with the success and durability of knee arthroplasty over the same time period.⁷

Surgical arthroscopy as a form of treatment for degenerative joint disease of the knee was first developed in the 1920s.⁸ In the 1930s, Burman et al looked at 30 cases of patients treated with knee arthroscopy and found generally positive results.⁹ Dr. Masaki Watanabe helped popularize the arthroscopic lavage in 1950s, perfecting the techniques of knee arthroscopy and also finding positive results when treating patients with knee OA.¹⁰

Bone marrow stimulation (BMS) has also been utilized in the treatment of OA. BMS was first devised in the 1950s as an open procedure and involves drilling through the damaged cartilaginous surface and into the subchondral bone to stimulate bleeding, clot formation, and the migration of stem cells. While BMS has evolved into a variety of techniques utilized today for managing focal cartilage defects, they have not been successful in treating the diffuse nature of osteoarthritis of the knee.¹¹

Without the long-term outcome data of total knee arthroplasty that we are privileged to have today,⁷,¹² many surgeons chose arthroscopy as treatment for knee OA, especially in younger patients. TKA was delayed for as long as possible, often at the expense of patients’ continued pain and decreased function. Arthroscopic débridement was seen as a minimally invasive option, which would provide pain relief, albeit temporarily, in patients who would otherwise be TKA candidates. The goal was to delay the need for a TKA until patients were older and less active. Consequently, given the increasing rate of OA, along with the intention of minimizing surgical trauma to the knee, arthroscopy became widespread.

Initial studies supported the idea that arthroscopic débridement provided patients with significant pain relief.¹³,¹⁴ Harwin found a 63% improvement in pain scores following surgical débridement, noting patients with more neutral mechanical axes had better results.¹⁵ Fond reported similar results: 25 out of 36 patients at 5 years had satisfactory results and improved HSS scores, with flexion contractures >10° being a negative prognostic factor of outcome.¹⁶

However, these early studies were often small case series, which lacked robust control groups. In response to this, several large clinical trials were performed in the late 1990s and 2000s, which called into question the efficacy of arthroscopy. The most influential study on the subject was a large prospective, randomized controlled trial comparing sham surgery versus arthroscopic débridement and meniscectomy in 2002 by Moseley et al. This study, published in the New England Journal of Medicine, found
no difference in terms of pain or function between sham surgery and the treatment group.¹⁷ Likewise in 2006, a Cochrane review article found a “Gold level of evidence” against arthroscopic débridement in patients with knee OA.¹⁸ A subsequent review by Barlow et al, a larger review than the Cochrane study, also found no indication for arthroscopy in OA. Though these studies, especially the Moseley study, were initially met with skepticism from the orthopedic community, they rightfully questioned orthopedists to evaluate the true indications for arthroscopy in knee OA patients.¹⁹

Following the release of the large controlled trials in the 2000s the indications for arthroscopy in patients with degenerative osteoarthritis of the knee decreased significantly. Improvements in radiography, as well as the more widespread availability of advanced imaging modalities including CT and MRI, have all but obviated the need for diagnostic arthroscopy to evaluate the extent of arthritis. In addition, large studies, including a well-known large randomized controlled trial from Finland, FIDELITY, have demonstrated no benefit of arthroscopic débridement in patients with either osteoarthritis or degenerative meniscus pathology, which had been one of the major indications.²⁰ Mechanical symptoms, once a fairly strong indication for arthroscopy, are no longer universally accepted following a recent review article which found no benefit from arthroscopy in this cohort either.²¹ Indeed, a 2016 randomized controlled trial from a group in Norway, comparing physical therapy and arthroscopic meniscus débridement with physical therapy, found no difference in long-term outcome and noted that the physical therapy group trended toward improved thigh strength with no difference in pain scores or function.²² Based on these data, along with other studies, the British Medical Journal recently released clinical practice guidelines strongly recommending against the use of arthroscopy for primary treatment of degenerative knee arthritis or degenerative meniscus tears.²³ Additionally, in a retrospective comparative study, Su et al demonstrated knee arthroscopy did not delay or decrease the knee for TKA, and did not provide pain relief past 2 years.²⁴ One recent systemic review of 20 different studies found that knee arthroscopy did not obviate the need for TKA, and that the median time between knee arthroscopy and TKA was a mere 2 years.²⁵ These studies in conjunction with the publication of long-term outcomes data on the TKA demonstrating excellent results at 20 and even 30 years postoperatively gave surgeons confidence to indicate younger more active patients who had previously been seen as arthroscopy candidates, for TKA.⁷,¹²

Despite the literature against the use of arthroscopy in the arthritic knee, many surgeons felt these studies may have overreached in claiming that there was no place for arthroscopy in the treatment paradigm. None of these studies were specific for patients with new onset knee pain or patients with an acute change in their pain. Indeed, this group often was actively excluded in some of these studies.²⁶ A recent article by Lamplot and Brophy, which reviewed major studies from 1975 to 2015, found that despite the evidence against arthroscopy, given the lack of specificity and power for certain patient subgroups, there still existed a specific role for arthroscopic débridement in certain patients with mild OA and symptomatic tears.²⁷

Often patients with stable, long-standing arthritis whose symptoms are controlled for an extended period may experience an acute change in their knee pain, both atraumatically and traumatically. MRIs in these patients may demonstrate flipped meniscus tears as seen in Fig. 24-1, which may become incarcerated between the femoral and tibial condyles and can cause severe pain, preventing knee extension. Similarly, loose bodies as seen in Figs. 24-2 and 24-3 may cause locking of the knee and are another strong indication for arthroscopic débridement given their propensity to cause pain, mechanical symptoms as well as due to their potential to cause damage to the articular surface of the joint. Removal of these loose bodies has demonstrated reliable pain relief.²⁸ In patients with these pathologies who previously had relief of their knee pain with conservative measures, arthroscopic débridement may return them to their baseline level of pain and function.

Presence of advanced degenerative changes in the knee is widely accepted as a major contraindication to arthroscopic débridement. To quantify the severity and extent of degenerative disease, surgeons often rely on the Kellgren-Lawrence grading system. This is a five-level radiographic grading system using weight-bearing radiographs, which ranges from grade 0 (no radiographic evidence of disease) to grade 4 (complete loss of joint space). Patients with advanced disease are categorized commonly as grade 3 and 4, while patients with more moderate disease are classified as having grades 1 and 2. Having worse than grade 2 is typically considered a contraindication to arthroscopy as these patients have been shown to have more rapid progression of arthritis following arthroscopic débridement than patients with grade 1 and 2.²⁵