Arthroscopic Debridement of the Arthritic Knee: Is There Still a Role?

Chapter Preview

CHAPTER SYNOPSIS

Routine arthroscopic debridement is not indicated for all patients with osteoarthritis. Considerable level 4 evidence supports some relief from arthroscopy, but some level 1 through 4 evidence casts doubt on the benefit versus placebo or simple lavage. Selection of patients with physical examination findings such as joint line tenderness, mechanical symptoms, and minimal deformity increases likelihood of response. Selection of patients with radiographic findings such as mild joint space narrowing, low-grade Fairbank changes, and minimal deformity increases likelihood of response. Further level 1 evidence is needed to confirm the subset of patients who are more likely to respond.

IMPORTANT POINTS

1

Medial joint line tenderness and positive McMurray test predict positive response.
2

Radiographic deformity predicts negative response.
3

Radiographic joint space less than 3 mm predicts negative response.
4

Radiographic high-grade Fairbank changes predict negative response.
5

Debridement of unstable meniscal tears and chondral flaps may improve response in patients with mechanical symptoms.

CLINICAL/SURGICAL PEARLS

1

Debridement of osteophytes is rarely indicated. Trimming of subluxed or destabilized (e.g., torn posterior root) menisci is unlikely to improve symptoms.
2

Focus debridement on mechanically unstable, impinging pathology such as cartilage flaps, loose bodies, and unstable meniscal tears.
3

Shaving of fibrillated worn cartilage is unlikely to yield lasting improvement.

CLINICAL/SURGICAL PITFALLS

1

More advanced cartilage surgery techniques including microfracture, plug transfers, and cultured chondrocyte implantation are unlikely to improve response in the degenerative knee.
2

Patients with advanced radiographic disease or deformity are unlikely to respond.

VIDEO AVAILABLE

1

Surgical video available.

HISTORY/INTRODUCTION/SCOPE OF THE PROBLEM

In the 1990s, several publications cast doubt on arthroscopic debridement for the osteoarthritic knee as a tool for routine use in all patients regardless of pathology. But the current debate on the topic was fueled by the randomized clinical trial with placebo control subjects published in the New England Journal of Medicine in 2002. This trial showed no difference in self-reported outcomes up to 24 months between arthroscopic debridement, lavage, and sham surgery in 165 randomized patients completing the trial. This publication generated enormous discussion among the popular press and an appropriately energetic reappraisal among the orthopedic specialist community. In response, the editor-in-chief of Arthroscopy wrote, “While I vigorously disagree with the conclusions being portrayed in the press, I am challenged to find good research to back up my arguments. This should give us pause to not only be critical of Dr. Moseley’s methodology, but also to be critical of ourselves for not filling the void in this important area of research.” Although the Moseley et al. study has been criticized for several serious methodologic flaws, its findings were largely confirmed by a second randomized clinical trial published in the New England Journal of Medicine in 2008. In this trial, 168 patients were assigned to either optimized conservative management, or conservative management following arthroscopic debridement. There were no significant differences in WOMAC scores or SF-36 scores at two year follow-up.

Despite these negative results, the Arthroscopy Association of North America has issued a position statement that there exists “a sub-group of patients with knee arthritis that can be significantly helped with appropriate arthroscopic surgery.” Here, we highlight some of the evidence in support of this statement. Substantial observational studies have sharpened the criteria by which the subset of responders can be identified. The most important clinical and radiographic criteria for patient selection are presented below. At the present time, surgeons should use evidence-based guidelines and careful patient selection to improve the chances of response. However, no further level 1 evidence has emerged to strongly predict this subset of patients, so patient counseling and reasonable expectations are imperative.

INDICATIONS/CONTRAINDICATIONS

Patients are selected based on factors likely to increase the chance of lasting pain relief. Figure 1-1 summarizes clinical decision making based on the results of the published evidence as discussed in this section. Acute onset of pain, mechanical symptoms such as locking and catching, recurrent effusions, and joint line tenderness in a patient with radiographically mild disease may predict greater and longer lasting relief following arthroscopy.

Several studies indicate that significant deformity, flexion contracture greater than 10 degrees, or radiographically narrow joint space correlates with poor response. Retrospectively, the presence of unstable meniscus tears visualized at the time of arthroscopy correlates with better response, but care must be taken in prospectively diagnosing meniscus pathology by magnetic resonance imaging (MRI) because degenerative tears frequently occur as part of the natural history of progressive arthrosis (see classification system later).

Dervin et al. retrospectively studied predictors of response at 2-year follow-up. Examination findings of medial joint line tenderness and a positive Steinman test correlated with response. Intraoperatively, the presence of an unstable meniscal tear correlated with response by WOMAC score. In this chapter, we recommend the use of the McMurray test, as it is closely related to the Steinman test but better known by most practitioners.

Aaron et al. studied factors predictive of response to debridement retrospectively at mean 34-month follow-up. Normal alignment, joint space width equal to or greater than 3 mm, and mild radiographic disease were correlated with response. Spahn et al. studied predictors of response after debridement of medial compartment disease retrospectively at minimum 4-year follow-up. Patients with more than three of the following risk factors had significantly poorer outcome: disease for longer than 24 months, obesity, smoking, osteophytosis, joint space width less than 5 mm, absence of effusion, absence of synovitis, presence of crystal deposits, deep tibial cartilage defect, and need for subtotal or total meniscectomy.

Last, patient age can be a major factor in decision making. For patients considered too young or active for arthroplasty and failing to respond to nonoperative management, even more advanced arthritic disease can be improved enough to “buy some time.”

CLASSIFICATION SYSTEM

Radiographic classification has a role in the evaluation of patients with osteoarthritis if they are being considered to be a candidate for arthroscopy, but MRI should be used with discretion. Radiographic classification is useful because progressive x-ray changes correlate with higher-grade chondrosis at the time of arthroscopy and predict poorer response. A classic radiographic classification is attributed to Kellgren and Lawrence. Progressive findings include (1) minimal joint space narrowing; (2) minimal osteophytosis; (3) moderate narrowing, and osteophytosis; and (4) joint space obliteration with severe osteophytosis and sclerosis. The grading system of Fairbank is well known to most practitioners, although it was originally studied in the postmeniscectomy knee. Findings such as (1) ridge formation, (2) squaring of the condyle, (3) joint space narrowing, and (4) subsequent osteophytosis and sclerosis indicate progressive disease. In addition to weight-bearing posteroanterior views and non–weight-bearing lateral views, we recommend weight-bearing flexion posteroanterior views and patellofemoral views (e.g., sunrise, Merchant) to provide the best assessment of the degenerative knee, especially in patients who may be a candidate for arthroscopic debridement. Figure 1-2 presents typical views, which highlight joint space narrowing and other features that are predicative of response to arthroscopy. Different radiographic classification systems have been proposed by the American College of Rheumatology and other groups.