Early blood flow restriction therapy may improve pain, strength after ACL reconstruction
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SAN DIEGO — Results showed use of blood flow restriction therapy in the early postoperative period after ACL reconstruction may improve short-term pain scores and quadriceps strength within the first 3 months after surgery.
Edward S. Chang, MD, and colleagues randomly assigned 26 patients undergoing ACL reconstruction to receive either a traditional rehabilitation program or a modified program using blood flow restriction therapy with low intensity exercises beginning 10 to 14 days postoperatively. Researchers assessed VAS pain scores and IKDC outcome scores both preoperatively and during the first 12 weeks postoperatively.
“We measured their thigh circumference immediately postoperatively and then weekly afterwards,” Chang, director of sports medicine research in the department of sports medicine at Inova Health System, told Healio Orthopedics about a study presented at the American Academy of Orthopaedic Surgeons Annual Meeting. “We also measured their quadriceps strength and compared that as a percentage to the contralateral side.”
Chang noted patients in the blood flow restriction group had significantly increased terminal knee extension strength at 8, 10 and 12 weeks postoperatively, as well as an overall change in strength from 3 to 12 weeks postoperatively. Although patients in the blood flow restriction group had a significantly lower VAS pain score at 6 weeks compared with the traditional rehabilitation group, Chang noted that pain scores normalized in the two groups by 3 months postoperatively. He added the two groups had no significant differences in IKDC score or thigh circumference.
Based on the results of this study, which received the O’Donoghue Sports Injury Research Award at the American Orthopaedic Society for Sports Medicine and Arthroscopy Association of North America Combined Meeting, Chang said blood flow restriction may be most beneficial in the early postoperative period after ACL reconstruction, when patients are unable to safely perform high intensity exercises.
“Further research is necessary, but my feeling is that [blood flow restriction] might be a standard of care postop modality for the majority of lower knee reconstructive surgeries to help prevent muscle atrophy and promote muscle hypertrophy,” Chang said.
Perspective
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Blood flow restriction was developed in Japan by Yoshiaki Sato, MD, PhD, in 1966. In Japan, it is known as “KAATSU,” which means “additional pressure.” It was finally developed into a commercial unit in 2006, and there are more than 160 peer-reviewed articles in the scientific literature, and Edward S. Chang, MD, and colleagues’ research is the latest using blood flow restriction. They assigned 26 patients undergoing ACL reconstruction for its use beginning 10 to 14 days after surgery and continuing out to 12 weeks.
Blood flow restriction has been shown to have beneficial effects in improving strength and limiting muscle atrophy associated with injury and chronic degenerative disease, especially in the knee. Blood flow restriction entails an application of an extremity tourniquet to restrict arterial inflow and occlude venous outflow creating an anaerobic environment. The actual mechanism of improving strength and muscle girth is not completely understood but may be a combination of upregulating cell signaling, improving protein synthesis and leading to an anabolic response. Chang and colleagues showed an initial decrease in VAS, but no difference in IKDC outcome score of thigh circumference at 12 weeks.
There is still much to learn and great variability in blood-flow restriction treatment regimens. We have the most experience with our ACL patient population and there appears to be a benefit in using it preoperatively and postoperatively in improving quadricep strength and girth, but the ultimate benefit of functional outcomes is still to be determined.
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Curley AJ, et al. Paper 197. Presented at: American Academy of Orthopaedic Surgeons Annual Meeting. Aug. 31-Sept. 3, 2021; San Diego.
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