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• The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.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: 27 February 2007
Target date for publication of guidance: May 2007

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

Current evidence suggests there are no major safety concerns associated with the use of arthroscopic knee washout with or without debridement for osteoarthritis. Evidence of efficacy is limited but is adequate to support the use of arthroscopic knee washout, done with the intention to perform debridement if necessary, provided that normal arrangements are in place for consent, audit and clinical governance.

Arthroscopic knee washout done without the intention to perform debridement is not supported by adequate evidence of efficacy. Clinicians should therefore ensure that patients understand the uncertainty about the efficacy of arthroscopic knee washout alone and provide them with clear written information. In addition, use of the Institute’s information for patients (‘Understanding NICE guidance’) is recommended (available from www.nice.org.uk/IPGXXXpublicinfo). [[details to be completed at publication]].

Arthroscopic knee washout 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 medications 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) to reduce pain and swelling. Corticosteroids or hyaluronic acid may be injected into the knee joint. If these treatments are ineffective, a knee replacement operation may be necessary.

One randomised controlled trial of 180 patients compared arthroscopic lavage alone versus arthroscopic debridement versus placebo (simulated arthroscopy) and showed no significant differences in terms of pain relief or knee function at 2 years. A second randomised controlled trial 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 randomised controlled trial 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 joint stiffness or function. A randomised controlled trial of 32 patients found no significant difference between arthroscopic and closed-needle washout in terms of clinical or functional outcomes at 12 months. Another randomised controlled trial of 38 patients comparing hyaluronic acid injections with arthroscopic washout reported no significant differences in pain or function at 1 year.

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 after a mean follow-up of 7.4 years, including 25 joint arthroplasties. In the above case series patients were treated with washout and with the intention of carrying out debridement. For more details, refer to the sources of evidence (see appendix).

The Specialist Advisers stated that there is uncertainty about the efficacy of this procedure. They listed the key efficacy outcomes as relief of pain and reduction of mechanical symptoms.

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).

It was noted that the micro-fracture technique may be used as an adjunct to this procedure but evidence relating to this was not considered by the Committee.

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

• 'Systematic review of the safety and efficacy of arthroscopic knee washout with or without debridement for the treatment of osteoarthritis', September 2006.