CDC data show that knee arthroscopy is one of the most frequently performed ambulatory orthopedic procedures in the United States. The surgery is now primarily used for the removal of loose bodies, debridement of meniscal tears, debridement and recontouring of cartilage flaps, arthroscopically assisted ligament reconstruction and meniscal transplantation, and synovectomy. In the early 1980s, there was a shift toward performing some surgical procedures on an outpatient basis for a variety of reasons. “Advances in anesthesia and surgical techniques, financial incentives to providers and patients, and enhancements in postoperative pain management were all factors that led to this shift,” explains Richard A. Marder, MD. “It’s well understood that the number of ambulatory surgical procedures is increasing, but there has been little study exploring the frequency and magnitude of these procedures occurring in outpatient settings in the U.S.”

Significant 10-Year Trends

In the June 1, 2011 Journal of Bone and Joint Surgery, Sunny H. Kim, PhD, Jose Bosque, MD, John P. Meehan, MD, Amir Jamali, MD, and Dr. Marder had a study published that described the changes in demographics and utilization of knee arthroscopy in ambulatory settings between 1996 and 2006 in the U.S. The investigation, which analyzed CDC data from the National Survey of Ambulatory Surgery, also sought out to determine the most common reasons for knee arthroscopy over the past decade. “Our analysis revealed several interesting trends,” says Dr. Marder. “First, between 1996 and 2006, the number of knee arthroscopies increased by 49% (Table 1). The increase in knee arthroscopy procedures was much steeper than the growth of the U.S. population during the same period.”

“Clinicians should continue to refine the indications for knee arthroscopy to improve upon its successful outcomes and minimize suboptimal outcomes.”

– Sunny H. Kim, PhD

Dr. Kim adds that the rate of knee arthroscopic surgeries per population size was two-fold higher than that of England or Ontario, Canada. “This finding,” she says, “may be due to patients in the U.S. preferring to select surgery before attempting other nonsurgical treatments, resulting in higher utilization of arthroscopy.”

The number of MRI units also more than doubled over the past decade. In addition to this increase, patient-generated demand and the practice of defensive medicine have been proposed as contributing factors to the increased use of MRI. As the use of MRI on lower extremities has increased dramatically, so too has the use of therapeutic arthroscopy of the knee. However, it is still unclear if the increased use of MRI has improved patient care.

Increase in Meniscal Tears

The most common reasons for knee arthroscopy, according to the Journal of Bone and Joint Surgery study, were related to knee injuries (Table 2). “In 2006, nearly 500,000 patients underwent arthroscopy for medial or lateral meniscal tears,” says Dr. Kim. “This total is approximately 100,000 more procedures than were performed in 1996.” The increased use of arthroscopy for meniscal tears, in part, may be due to surgeon coding. Since 2004, Medicare no longer pays for knee arthroscopy performed to treat osteoarthritis. On the basis of insurance authorization, many cases that would have had a diagnostic code for knee arthritis may be coded more recently as meniscal tears because many knees with osteoarthritis also demonstrate degenerative meniscal tears.

Looking Forward

Dr. Kim notes that it is unknown if there is more disease or just more utilization of arthroscopy because the decision to perform these procedures is largely subjective. “Meniscal tears were the most common reason for arthroscopy, but not all meniscus tears are the same size or shape,” she says. “Clinicians should continue to refine the indications for knee arthroscopy to improve upon its successful outcomes and minimize suboptimal outcomes. The development of guidelines for patient selection—with help from national societies and professional orthopedic associations—may ultimately lead to the establishment of such criteria and reduce overuse. More research is needed to better define symptoms, physical findings, and radiographic findings that are predictive of successful arthroscopic treatment.”