Patients over 70 years of age, scheduled for joint replacement surgery will be randomized to tramacet/ naloxone plus morphine PCA or to morphine PCA to assess quality of analgesia in the postoperative period.

The primary objective is to determine opioid use during combined use of oral tramacet and naloxone infusion perioperatively in elderly patients (70 yrs and older) having elective knee/ hip arthroplasty under spinal anesthesia.

Secondary objectives are to determine the incidence VAS scores ≥4 and adverse effects such as nausea, vomiting, sedation, respiratory depression, pruritus, confusion, and time of independent mobilization.

Hypothesis: Perioperative naloxone infusion and tramacet provides adequate analgesia in elderly patients undergoing total knee/hip arthroplasty and is associated with 80% reduction in opioid use and reduced opioid-induced side effects.

• Hip Arthroplasty
• Knee Arthroplasty
• Spinal Anesthesia

• Drug: tramacet, naloxone
• Drug: tramacet
• Drug: Acetaminophen

• Experimental: Group A oral tramacet 2 tablets preoperatively, 2 tablets every 6 hours for 5 days then 1-2 tablets of tramacet prn to a maximum of 8 tablets per day. Naloxone infusion starting preop at 0.25ug/kg/hr and continuing during hospital stay (an equivalent of 400ug over 24 hours in a 70 kg man). The infusion will be discontinued 1 hour before patient discharge.
• Active Comparator: Group B will receive oral tramacet 2 tablets preoperatively and then 2 tablets every 6 hours for five days. ( or until discharge. Patient VAS after discontinuation of morphine PCA may dictate addition of oral narcotic oxycodone after discharge). This group will also receive saline infusion at 4-6mls / hour for the duration of the hospital stay.
• Active Comparator: Group C will receive oral Acetaminophen tablets 1 gm preoperatively and subsequently 6 hourly plus an infusion of saline (placebo) at a rate of 4-6mls / hour for the duration of their stay.

Inclusion Criteria:

1. Aged 70 years and older*
2. Able to give informed consent
3. Able to communicate in English
4. Having elective hip/knee arthroplasty
5. ASA physical status 1-3.

Exclusion Criteria:

1. Allergies to any of the following: naloxone, tramacet, NSAIDs, or local anesthetic
2. Contraindication to spinal anesthesia
3. Contraindication to use of tramacet or celebrex
4. ASA physical status 4
5. Chronic opioid use
6. Chronic pain syndrome All the above will be included in the letter of information