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Ask the Experts: Use of drains in total knee replacement
SAN DIEGO — Though the statistical differences are few, there are still some controversial differences to be taken into account when using drains, according to two physicians who debated the legitimacy of the reported benefits of drainage following total knee replacement.
The presentations were part of a symposium at the 2011 Annual Meeting of the American Academy of Orthopaedic Surgeons, here.
Gerard A. Engh, MD, and Michael E. Berend, MD, brought their opposing viewpoints to the table, with Engh insisting drainage had significant benefits and Berend believing the only benefits were in the patient's head.
What happens to the blood?
 Gerard A. Engh |
“Those who believe in drains have reported [that] advantages are less pain and swelling, decreased risk of infection, [and] quicker recovery of mobility ...,” Engh said. He noted that those who argue against drainage say there is less bleeding with the tamponade effect, a decreased risk of infection because there is no portal of entry for bacteria and a lower cost.
Engh added that the literature cannot address the issue of infection due to inadequate power, and noted there is no difference in quicker recovery or cost, leaving “one salient issue” — impact on bleeding.
He noted a number of studies that pointed out no statistical differences in the amount of bleeding.
“So what happens to all of this blood?” he said.
According to Engh, numerous studies have pointed out that, on average, Hemovac drainage collects 500 ml to 750 ml of blood with no difference in postoperative hemoglobin or hematocrit reported – meaning without a Hemovac “two units of blood either drains through the incision or collects in the soft tissues.”
“If you want blood all over the dressing, the surgical stock, the knee immobilizer and the sheets, please do not use a Hemovac drain,” Engh concluded. “If you want a happy patient … I would strongly urge you to use a drain.”
 Michael E. Berend |
“[Engh] already articulated there is no significant difference in using a drain other than perceived happiness, so I will take the null hypothesis that drains do not have to be used in total knee replacement,” Berend said.
Theorectial differences
Berend noted the same “theoretical” advantages Engh pointed out, but added they are “dogma based on fear rather than evidence,” saying overwhelming evidence points toward drains making no difference for the patient or the hospital.
He pointed out a study his group published wherein no difference was found in excessive drainage, the amount of transfused blood, range of motion at 7 days and hemoglobin levels.
“If you dive further into the data, it is a significant cost that results in no improvement in range of motion or hemoglobin in any patients in the randomized study,” he said.
Looking at the value of reinfusion drains for unilateral total knee replacement also reveals no significant difference in transfusion rate, Berend reported. With most studies being underpowered, he turned to a meta-analysis to point out that in 5,000 knees there were higher transfusion rates in drained knees.
Berend added that while there was more bruising and need for dressing reinforcement without a drain, the important factors to the patient — differences in hematoma, wound infection and reoperation — did not change.
“The data in no way supports routine use of drains in total knee replacement,” he concluded.
References:
- Berend ME. Drains do not need to be used after TKR. Part of symposium B, “Debates on contemporary issues in total knee replacement.” Presented at the 2011 Annual Meeting of the American Academy of Orthopaedic Surgeons. Feb. 15-19, 2011. San Diego.
- Engh GA. Drains should be used after TKR. Part of symposium B, “Debates on contemporary issues in total knee replacement.” Presented at the 2011 Annual Meeting of the American Academy of Orthopaedic Surgeons. Feb. 15-19, 2011. San Diego.
Disclosures: Engh receives royalties from DePuy and Innomed, is a member of the speakers bureau for Smith & Nephew, is a paid consultant for DePuy and Smith & Nephew, is an unpaid consultant for and owns stock or stock options in Alexandria Research Technologies, and receives institutional support from DePuy, Smith & Nephew, and U.S. Army Medical Research & Materiel Command & the Telemedicine & Advanced Technology Research Center, as well as Medtronic and Inova Health Systems. Berend receives royalties and research support from Biomet, is a member of the speakers bureau for Biomet and ERMI, and is a paid consultant for Angiotech.