EBQ:Moseley Trial

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Study: Moseley et al.. A controlled trial of arthroscopic surgery for osteoarthritis of the knee. The New England journal of medicine 2002. 347:81-8. PMID: 12110735. DOI.

Clinical Question

In patients with knee osteoarthritis (OA), does arthroscopic debridement or lavage reduce knee pain at two years?

Bottom Line

In patients with knee OA, there was no difference between level of knee pain following arthoscopic debridement, arthoscopic lavage, or sham arthroscopy at two years.

Major Points

Arthroscopic interventions have been widely used for the treatment of symptomatic knee OA, but the practice is controversial, because its efficacy has not been clearly established in clinical trials.[1] The Moseley Trial randomized 180 predominantly white, male patients with symptomatic and radiographic evidence of knee OA to arthroscopic debridement, arthroscopic lavage, or sham arthroscopy performed by a single orthopedic surgeon in Texas. At two years, there was no difference in pain and function between the arthroscopic interventions and sham surgery.

Of note, the randomization of patients to sham surgery was met with considerable controversy. The trial is occasionally misrepresented as having established that knee arthroscopy is ineffective in a wide range of problems (eg, meniscal tears); in fact, however, it only demonstrated that arthroscopy was likely not efficacious among patients with knee OA.


American Academy of Orthopaedic Surgeons (2013)[2]

  • The group cannot recommend performing arthroscopy, lavage, or both in patients with primary symptomatic knee OA (Strong recommendation)


  • Single-center, double-blind, parallel group, randomized, placebo controlled trial
  • N=180 patients with knee OA
    • Arthroscopic lavage and debridement (n=59)
    • Arthroscopic lavage (n=61)
    • Sham arthroscopy (n=60)
  • Setting: Veterans Affairs Medical Center in Texas
  • Enrollment: 1995-1998
  • Follow-up: 2 years
  • Analysis: Per-protocol
  • Primary outcome: Knee pain at two years by the Knee-Specific Pain Scale (KSPS)[3]


Inclusion Criteria

  • Age โ‰ค75 years
  • Knee OA with at least moderate pain despite โ‰ฅ6 months of maximal medical treatment

Exclusion Criteria

  • Knee arthroscopy in previous two years
  • Radiographic severity score of โ‰ฅ9
  • Severe deformity
  • Serious medical comorbidities

Baseline Characteristics

  • Demographics: Age 52.3 years, male 92.8%, White race 60.0%
  • OA severity:
    • Mild: 28.9%
    • Moderate: 46.1%
    • Severe: 25.0%
  • Non-prescription analgesics: 67.2
  • Knee Society Clinical Rating Scale (out of 100, higher number representing lower severity)
    • Symptoms: 50.3
    • Function: 60.7
  • Psychological attributes (out of 100, higher number representing higher severity)
    • Anxiety: 28.5
    • Depression: 23.4
    • Expectation for benefits: 3.5
    • Optimism: 73.6
    • General health satisfaction: 43.2
    • Social functioning: 64.5
    • Somatization: 10.3
    • Stress: 27.5
    • Vitality: 55.1


  • Severity of three knee compartments were assessed radiographically and graded on a scale of 0 to 4; composite of scores were added to generate severity grade of 0 to 12
  • Randomization with stratification by radiographic severity (grades 1-3, 4-6, and 7-8) to one of three groups, with assignment revealed to the surgeon only after the patient was in the OR.
    • Arthroscopic lavage and debridement under general anesthesia with intubation, included lavage with โ‰ฅ10 L fluid, chondroplasty, removal of loose debris, trimming of degenerating meniscal fragments, and shaving of spurs from tibial spine preventing full extension
    • Arthroscopic lavage under general anesthesia with intubation, included lavage with โ‰ฅ10 L fluid only unless unstable meniscal tear encountered which was subsequently repaired
    • Sham arthroscopy with short-acting intravenous tranquilizer, opioid, no intubation; three 1-cm incisions performed and entire procedure mimed
  • Follow-up by blinded study personnel at 2 weeks, 6 weeks, 3 months, 6 months, 12 months, 18 months, and 24 months


Comparisons are debridement vs. lavage vs. sham (debridement vs. sham; lavage vs. sham).

Primary Outcomes

Mean KSPS scores for knee pain at 2 years
51.4 vs. 53.7 vs. 51.6 (P=0.96; P=0.64)

Secondary Outcomes

Mean AIMS2-WB scores for walking and bending at 2 years (higher is worse)
56.4 vs. 51.1 vs. 53.8 (P=0.64; P=0.61)
Mean Physical Functioning Scale scores (higher is worse)
Two weeks: 48.3 vs. 53.0 vs. 56.0 (P=0.02; P=0.22)
One year: 45.6 vs. 50.4 vs. 52.5 (P=0.04; P=0.09)
Two years: 47.7 vs. 53.2 vs. 52.6 (P=0.11; P=0.13)

Additional Analyses

Difference between participants vs. 44% who declined to participate
Age: 52.3 years vs. 55.3 years (P=0.002)
White: 62.2% vs. 50.7% (P=0.003)
Severe OA: 25.0% vs. 12.5% (P<0.001)

Adverse Events

No significant adverse events.


  • Single-site where one surgeon performed all the procedures
  • Patient population was predominantly white and male
  • Selection bias: 44% declined participation
  • Small sample size[4]
  • May not be generalizable to younger patients with early-stage OA, who may benefit from arthroscopic debridement [5]
  • KSPS is not validated[4]
  • No intention-to-treat analysis


Supported by a grant from the Department of Veteran Affairs

Further Reading