The primary outcome of this study is to determine the true incidence of smokers among patients undergoing joint replacement and secondly, what percent are able to quit smoking before surgery under a structured cessation program with carbon monoxide breath testing. The investigators hypothesize that self-reported smoking status is underreported and that routine carbon monoxide breath testing will improve abstinence rates at the time of surgery.

This study looks at patients who have been referred to our clinic for a potential hip and knee joint replacement surgery. Once it has been determined that the patient requires surgical replacement of either their hip or knee and is placed on our surgical waitlist, the patient will be asked if he or she would like to participate in the study. The investigators would ask all patients, both self-declared smokers and non-smokers, to participate. This study would include completing a smoking history questionnaire and a noninvasive carbon monoxide breath test. While smoking status is already assessed in the McGill University Health Centre preoperative questionnaire, the investigators intend on expanding these questions in study participants to better quantify their nicotine exposure.

Inclusion Criteria:

• Adults ages 18-85 who require a primary total hip or knee replacement
• Any gender
• Smokers and non-smokers
• Osteoarthritis, rheumatoid arthritis, avascular necrosis

Exclusion Criteria:

• Patients who require revision surgery
• Previous fracture to affected area
• Emergency surgery
• Patients who do not understand, read or communicate in either French or English

Patients who have been referred to our outpatient orthopaedic clinic for a potential hip and knee joint replacement and have been placed on our surgical waitlist for surgery.