Eight RCTs provide weak and inconsistent evidence that arthroscopic lavage and debridement, or tidal irrigation, are beneficial for osteoarthritis of the knee.

Background

• Arthroscopic lavage and debridement involves:
• Arthroscopy — insertion of a fibreoptic instrument into the knee and inspection for disease, requiring a general anaesthetic.
• Lavage — irrigation of the joint with a large volume of fluid, which may remove microscopic and macroscopic debris resulting from cartilage breakdown, as well as removing the pro-inflammatory effects of this material.
• Debridement — surgical removal of obviously frayed cartilage or meniscal surfaces.
• Tidal irrigation involves irrigating the joint through a needle inserted into the knee joint under local anaesthesia; a large volume of fluid is run into the knee and then allowed to drain out. The rationale is the same as for arthroscopic lavage.

Evidence summary

The National Institute for Health and Clinical Excellence (NICE) conducted a systematic review of the efficacy and safety of arthroscopic lavage, debridement, and tidal irrigation for osteoarthritis of the knee [National Collaborating Centre for Chronic Conditions, 2008].

Eight relevant RCTs were found assessing invasive treatments of osteoarthritis of the knee. The studies differed with respect to comparisons, numbers of participants, and duration of follow up.

• Lavage for knee osteoarthritis:
• Pain: four RCTs (n = 180, n = 34, n = 20, n = 98). One of the four RCTs found significant benefits for lavage. Each study used several different measures of pain, and results were consistent within studies.
• Stiffness: one RCT (n = 20). Results were inconsistent: one measure of stiffness (gelling) favoured the use of lavage, while the other measure (duration of morning stiffness) did not.
• Function/disability: four RCTs (n = 180, n = 34, n = 20, n = 98). No significant benefits for lavage. Studies used several different measures of function/disability, and results were consistent within studies.
• Global assessment: two RCTs (n = 34, n = 98). The larger study found no benefits for lavage, and results were inconsistent in the smaller study.
• Quality of life: one RCT (n = 34). No benefits for lavage were found on three different measures of quality of life.
• Tidal irrigation for knee osteoarthritis:
• Pain: three RCTs (n = 180, n = 77, n = 90). The two smaller RCTs found significant benefits for irrigation. Each study used several different measures of pain, and results were consistent within studies.
• Stiffness: three RCTs (n = 180, n = 77, n = 90). The smallest RCT found significant benefits for irrigation. One study used two different measures of stiffness, and its results were consistent.
• Function/disability: three RCTs (n = 180, n = 77, n = 90). No significant benefits for irrigation. Studies used several different measures of function/disability, and results were consistent within studies.
• Global assessment: two RCTs (n = 180, n = 77). The smaller study found benefits for irrigation, while the larger study found no difference between irrigation and control treatment.
• Quality of life: one RCT (n = 180). No benefits for irrigation were found.
• Use of rescue medication/analgesia: one RCT (n = 180). No benefits for irrigation were found.