To the Editor:
I read with interest the article, “Pain control infusion pumps: a prospective randomized evaluation in bilateral total knee arthroplasty” ( http://www.orthosupersite.com/view.aspx?rid=80984) in the March 2011 issue of ORTHOPEDICS. I am a retired orthopedic surgeon. During my career, I was a professor of orthopedics at George Washington University in Washington, DC, and head of the Pediatric Orthopedics Department of Children’s Hospital from 1972 to 1989.
In 1990, I became interested in pain control in total knee arthroplasty (TKA). I tried bupivicaine solution by direct infusion into the joint postoperatively. I performed 8 cases and found that marcaine is dose sensitive to the cardiovascular system. One patient went into shock and 2 others had a drop in blood pressure. By trial and error, we developed a cocktail of compatible drugs by King’s Guide of lidocaine 1/8th percent, hydrocortisone 400 mg, heparin 1000 mg, and chloromycetin 1 g in 1000 cc of saline. We also measured the amount of cocktail solution to cause slight leakage of the wound for complete relief of pain. We cultured 50 consecutive catheter tips and skin edge of the knees when drains were removed at 72 hours.
Evaluating pain is a problem for all of us. I felt that I could measure the degree of motion obtained on day 3 by a continuous passive motion machine and measure the milligrams of intravenous rescue morphine. We performed 136 single primary TKAs with the K-cycle. I compared them with 12 TKAs with epidural analgesia and 18 TKAs with the standard use of intravenous morphine (Table). I was the surgeon in all cases. The blood saver made the first day useless. Therefore, my measurements were taken on days 2 and 3 with rescue morphine, and range of motion was measured on day 3 when the drains were removed. A professor of statistics reviewed the numbers and said the Q was acceptable.
Table: Average Results of 136 Knees
There was an average increase in knee motion by 44% on day 3 and an average decrease in rescue morphine by 81.5%. There was 1 blood-borne infection, when, during the sixth week of recovery, the patient was cooking and burned his arm, which became infected, and his knee was infected by the same organism. The infection was treated by the K-cycle with antibiotics and cleared nicely. There were only 2 bilateral simultaneous TKAs in the study. Neither patient received rescue morphine on the second or third day postoperatively.
Douglas W. McKay, MD
Average Results of 136 Knees
|Length of Stay, d||Rescue Morphine, mg||ROM, deg|
|Day 2||Day 3|
We appreciate the interest in our research. We too are interested in optimizing postoperative pain protocols for our joint arthroplasty cases. Continuous local anesthetic infusion pumps are just 1 component of a more extensive pain protocol system that we currently use at our hospital. Anecdotally, we have found success using pericapsular injections of a cocktail including local anesthetic, morphine, and ketorolac. Dr McKay accurately reports on the subjectivity inherent with all investigations evaluating pain control. We hope both studies serve to stimulate investigation into optimal postoperative pain protocols.
Evan Argintar, MD