An arthroscopic knee washout involves flushing the knee joint with fluid, which is introduced through small incisions in the knee. The procedure is often done with debridement, which is the removal of loose debris around the joint.

The National Institute for Health and Clinical Excellence is examining arthroscopic knee washout, with or without debridement, for the treatment of osteoarthritis and will publish guidance on its safety and efficacy to the NHS in England, Wales, Scotland and Northern Ireland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisers, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about arthroscopic knee washout, with or without debridement, for the treatment of osteoarthritis.

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

• comments on the preliminary recommendations
  
• the identification of factual inaccuracies
  
• additional relevant evidence.

Note that this document is not the Institute's formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that the Institute will follow after the consultation period ends is as follows.

• The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
  
• The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.

For further details, see the Interventional Procedures Programme manual, which is available from the Institute's website (www.nice.org.uk/ipprogrammemanual).

Closing date for comments: 22 May 2007
Target date for publication of guidance: August 2007

Note that this document is not the Institute's guidance on this procedure. The recommendations are provisional and may change after consultation.

Arthroscopic knee washout with or without debridement is used to treat osteoarthritis of the knee. Osteoarthritis of the knee is the result of progressive degeneration of the cartilage of the joint surface.

Treatment options depend on the severity of the osteoarthritis. The condition is usually chronic, and patients may have several treatment strategies applied at different stages. Conservative treatments include medication to relieve pain and inflammation, and physiotherapy. If there is a knee-joint effusion, fluid around the knee may be aspirated with a needle (arthrocentesis). Corticosteroids or hyaluronic acid are sometimes injected into the knee joint. If these treatments are ineffective, a knee replacement operation may be necessary.

One randomised controlled trial (RCT) of 180 patients compared arthroscopic lavage alone, arthroscopic debridement and sham procedure (simulated arthroscopy) with each other. The trial showed no significant differences in terms of pain relief or knee function at 2 years. A second RCT comparing debridement with washout alone reported that 59% (19/32) of patients in the debridement group were pain free at 5 years, compared with 12% (3/26) of patients in the washout group (p value not stated). A third RCT of 90 patients reported that pain relief at 12 months was significantly better in patients treated with 3-litre washout compared with patients treated with 0.25-litre washout (p = 0.02). However, there was no significant difference between the groups in terms of joint stiffness or function. An RCT of 32 patients found no significant difference between arthroscopic and closed-needle washout in terms of clinical or functional outcomes at 12 months. Another RCT of 38 patients comparing hyaluronic acid injections with arthroscopic washout reported no significant differences in pain or function at 1 year.

In the following three case series, patients were treated with washout with the intention of carrying out debridement. In one case series of 121 patients, 10% (12/121) required repeat arthroscopy and 12% (15/121) required knee replacement after a follow-up of 4-6 years. In another case series, 18% (18/100) of knees required further surgery after 5 years' follow-up (4 osteotomies, 3 unicondylar arthroplasties and 11 total knee replacements). A third case series reported that 23% (47/204) of knees required further surgery, which included 25 joint arthroplasties, after a mean follow-up of 7.4 years. For more details, refer to the sources of evidence (see appendix).

Few complications were reported in any of the studies. In one case series of 204 patients, haemarthrosis requiring aspiration occurred after 2% (4/204) of procedures and there was one case of deep venous thrombosis. For more details, refer to the sources of evidence (see appendix).

The use of this procedure in the treatment of rheumatoid arthritis was not considered.

The following document, which summarises the evidence, was considered by the Interventional Procedures Advisory Committee when making its provisional recommendations.

• ' Interventional procedure overview of arthroscopic knee washout with or without debridement for the treatment of osteoarthritis', September 2006.