Scoping for knee OA revisited: It's still not OK

Source: Kirkley A, Birmingham TB, Litchfield RB, et al. A randomized trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med 2008; 359:1,097-1,107.

Six years ago, The New England Journal of Medicine reported1,2 Moseley's study of the use of arthroscopy to treat knee osteoarthritis (OA). The conclusion was that patients randomized to surgery did not experience reduced pain or improved function. After the study was published, several concerns were raised, namely, the study group was composed of elderly male veterans,3 X-rays during posterior-anterior flexion in a weight-bearing position were not performed,4 the pain scale was not validated, and the study was underpowered.5

Alexandra Kirkley, MD, and colleagues from the University of Western Ontario report their trial that answers those concerns. Patients had to be at least 18 years old and without large meniscal tears. They screened 277 patients for eligibility, and after appropriate exclusion, they randomized 188. Reasons for exclusion included more than 5° of misalignment, inflammatory or post-infectious arthritis, previous arthroscopy, history of major knee trauma, severe OA, and corticosteroid knee injection in the last three months, among others. Subjects were X-rayed to grade the severity of OA, received a detailed physical examination of the knee, and completed several questionnaires and clinical scoring tools, including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Short Form-36 Physical Component Summary, both validated instruments.

Patients were randomized to the study group, which received optimized physical and medical therapy and arthroscopic treatment, or the control group, which received only the physical and medical therapy. Arthroscopic therapy could involve synovectomy, debridement, or excision of meniscal degenerative tears, cartilage fragments, or chondral flaps and osteophytes. Physical therapy involved one-hour weekly sessions for 12 weeks. Participants also were instructed in a home exercise program.

Medical therapy began with acetaminophen and nonsteroidal anti-inflammatory drugs, and progressed to hyaluronic acid injection if necessary. Patients also were offered oral glucosamine. Patients were seen periodically by a nurse who was blind to treatment, and all patients wore a neoprene sleeve over their knees to hide the study groups' surgical scars. There were 94 patients assigned to surgery; two withdrew consent, and six declined to undergo arthroscopy. The same number was assigned to the control group. Eight withdrew consent. The two groups were similar in all respects. They were in their late 50s and predominantly female, with a body mass index of 31 kg/m2.

At the three-month check, the WOMAC scores in the surgery group showed greater improvement than the control group. After that and through two years of follow-up, there were no significant differences between the groups. Both groups showed improvement. The investigators performed subgroup analysis for patients who were having mechanical symptoms of catching or locking; again, there was no difference between the groups. When physical function, pain, or quality of life was compared, the groups were similar.

References

  1. Moseley JB, et al. A controlled trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med 2002; 347:81-88.
  2. Wilke AJ. Should 'my friend Arthur' have a visit from the scope? Intern Med Alert 2002; 24:113-114.
  3. Jackson RW. Arthroscopic surgery for osteoarthritis of the knee. N Engl J Med 2002; 347:1,717-1,719.
  4. Ewing W, Ewing JW. Arthroscopic surgery for osteo-arthritis of the knee. N Engl J Med 2002; 347:1,717-1,719.
  5. Chambers KG, Schulzer M. Arthroscopic surgery for osteo-arthritis of the knee. N Engl J Med 2002; 347:1,717-1,719.