Hypothesis: General anesthesia as compared to intrathecal (i.e. spinal anesthesia) anesthesia will result in shorter length of hospital stay for patients undergoing total knee arthroplasty.

Primary endpoint: time from end of surgery until the patient is "street ready"

Secondary endpoints: will general anesthesia produce less postoperative pain as compared to intrathecal anesthesia? Is there any difference in post operative "dizziness" between the groups.

Hypothesis: General anaesthesia compared to intrathecal anaesthesia will give shorter length of hospital stay (LOS) for patients undergoing total knee arthroplasty (TKA).

Primary endpoint: time from end of surgery until the patient meets the discharge criteria.

Secondary endpoints:

1. Will general anesthesia produce less post operative pain?
2. Is there any difference in post operative orthostatic function (dizziness) between the groups?
3. Time until the patient meets the discharge criteria from PACU
4. How many patients will need at least one urinary bladder catheterization?

Inclusion Criteria:

1. patients with osteoarthritis scheduled for surgery
2. patients that will require Total Knee Arthroplasty
3. patients over 45 yrs and under 85 yrs
4. patients that understand the given information and are willing to participate in this study
5. patients who have signed the informed consent document

Exclusion Criteria:

1. prior surgery to the same knee
2. patients with a history of stroke or neurological or psychiatric disease that potentially could affect the perception of pain
3. obesity (BMI> 35)
4. active or suspected infection
5. patients taking opioids or steroids
6. patients suffering from rheumatoid arthritis or have a immunological depression.
7. patients who are allergic to any of the drugs being used in this study
8. patients with other severe medical problems that could affect the perioperative course.