• Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  
• Joint-Specific Multidimensional Assessment of Pain (J-MAP) to evaluate placebo effects on the different dimensions of pain [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  
• Patient satisfaction with their knee condition (SKIP) [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  

• SF-12 [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  
• Range of motion of each knee [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  
• Timed walking test [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  
• Locus of control [ Time Frame: Baseline ] [ Designated as safety issue: No ]
  
• Optimism [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  
• Self-efficacy [ Time Frame: baseline ] [ Designated as safety issue: No ]
  
• Cognitive pain [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  
• Anxiety [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  
• Social support [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  
• Patient reaction [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  
• Physician trust [ Time Frame: 3-month ] [ Designated as safety issue: No ]
  

This study will examine placebo responses in the context of practitioner-patient interactions at the time of the encounter. Phase 1 of this study identified patient-related determinants of placebo response, such as beliefs and expectations toward treatment of knee OA with acupuncture. Phase 2 of the study evaluated an assessment tool to measure these determinants. Phase 3 of the study is a randomized controlled trial to evaluate whether placebo effects in patients with knee OA can be enhanced by the acupuncturists' communicative style, which can affect a patient's cognitive expectancies and beliefs.

Patients will initially be randomized to one of two groups, each with a different model for practitioner-patient interaction. Acupuncture practitioners will be trained to follow semi-structured communicative styles, including traditional approaches in Chinese medicine and techniques previously described in patient-doctor communications studies. Within each of these groups, patients will be further randomized to receive either acupuncture or sham acupuncture. Patients will have 6 weeks of biweekly treatment visits. Patients will be followed for 6 months. Visits will be weekly during the first 6 weeks of the study and monthly thereafter.

The study will also include a natural cohort group composed of patients on a study waiting list; these patients will be offered acupuncture 3 months after study entry.

Inclusion Criteria:

• OA diagnosis according to the American College of Rheumatology criteria
• Pain in the knee of at least 3 or more on a 0 to 10 scale (0 none, 10 extreme pain) within 2 weeks prior to study entry
• Stable treatment with anti-inflammatory and analgesic medications during the month prior to study entry
• If receiving glucosamine, stable dosage for 2 months prior to study entry
• Adequate cognitive status as determined by the study officials
• Living in the community
• Ability to communicate in English without a translator
• Access to a telephone

Exclusion Criteria:

• Other diagnosed joint diseases, such as rheumatoid arthritis
• Previous treatment with acupuncture (for any condition)
• Intra-articular injections in the knee in the 2 months prior to study entry