Methods of Pain Control Compared after UKR

What’s the best way to control pain and swelling after a unicompartmental knee replacement (UKR)? That’s the focus of this study. UKR only replaces one side of the joint, usually the medial or inside half.

Three groups of patients were compared. Group one used a Cryo/cuff for the first 48 hours. The Cryo/cuff cools the knee while giving compression off and on at the same time. Group 2 had an epidural injection of anesthesia into the space around the spinal cord. Group 3 was the control group. They were given oral pain relievers.

Everyone had the same rehab program for six weeks. Patients were allowed to progress at their own pace. A home program of knee range of motion exercises was given. Full weight-bearing was allowed without a walking aid when the patient was ready for it.

Day 1: No difference between the Cryo group and the EDA group. This surprised the researchers because patients with EDA should be pain free. The control group used more morphine than either the Cryo or the EDA groups.

Day 2: No difference between the Cryo group and the EDA group. The control group used more morphine but the amount wasn’t significant compared to the other two groups.

Day 3: Cryo and EDA was stopped. The Cryo group had a gradual decrease in pain. The EDA group had slightly more pain.

Day 4: No morphine was needed by the Cryo group. Some patients in the EDA group still used Morphine until day 7.

Six weeks later: Patients in all three groups had about the same knee motion as before the operation. Function such as walking and stair climbing was much better.

The authors conclude that the Cryo/cuff works just as well as EDA for UKR in the first 48 hours. There’s no need to use the more invasive spinal injection. Physical therapists should note that motion training shouldn’t be rushed. Failure to increase range of motion should be monitored. Most of the patients regained their motion with a home program of exercise.