Citrus supplement may ease knee swelling and pain after surgery

For patients undergoing total knee arthroplasty (TKA), treatment with diosmin—a flavonoid supplement derived from citrus fruits—may achieve reduced knee and leg swelling and some measures of associated pain, reports a clinical trial in The Journal of Bone & Joint Surgery. The magazine is published in the Lippincott portfolio in association with Wolters Kluwer.

“The use of diosmin after TKA reduced lower extremity swelling and pain during movement and was not associated with an increased incidence of short-term complications regarding the outcomes studied,” according to new research by Pengde Kang, PhD, MD , of Sichuan. University, Chengdu, China and colleagues.

Potential new approach to relieve painful edema after TKA

Swelling is a common problem in patients undergoing TKA, and one that contributes to patient pain and dissatisfaction. “Postoperative lower extremity edema is a significant barrier to enhanced recovery in patients undergoing TKA,” the researchers write. Various measures have been suggested to reduce swelling, including rest, cold packs, and compression bandages, with mixed success. Currently, there are no effective drug options to reduce edema after TKA.

Diosmin – often in combination with a related flavonoid called hesperidin – has been used to reduce limb swelling in patients with venous disorders. Although diosmin is not approved as a prescription drug in the United States or Europe, experience shows that it is well tolerated with low toxicity. Based on these characteristics, the researchers designed a clinical trial to evaluate the efficacy and safety of diosmin in patients undergoing TKA.

The exploratory study included 330 patients undergoing TKA at 13 university hospitals. Patients were randomly assigned to one of two treatment groups, which received a 14-day course of diosmin beginning on postoperative day 1. or a control group, which received no study treatment. Both groups received standard pain medication.

Swelling at specific sites was measured at 1, 2, 3, and 14 days postoperatively and compared between the diosmin and control groups. Pain scores, knee function, complication rates and blood levels of certain inflammatory markers (C-reactive protein and interleukin-6) were also assessed.

Diosmin reduces swelling and pain with movement

Results showed reduced swelling in the knee, calf, and thigh up to 14 days after TKA in patients treated with diosmin. Swelling reduction was associated with lower pain scores on knee motion. In contrast, pain scores at rest were not significantly different for the diosmin versus control groups. Estimates of knee function recovery and levels of inflammatory biomarkers were similar.

Short-term complication rates were also similar between groups, supporting the safety of diosmin. There was a trend toward reduced rates of postoperative nausea and vomiting with diosmin, although the difference was not significant.

The study provides preliminary evidence that diosmin is a safe and effective treatment for reducing swelling and pain with movement after TKA. However, questions remain about how diosmin exerts these effects—particularly since the study found no change in levels of inflammatory biomarkers between the groups.

“This negative effect may reflect the effectiveness of the other anti-inflammatory drugs administered to both groups,” Dr. Kang and colleagues write. They emphasize the need for further studies to evaluate the mechanism by which diosmin reduces swelling and whether an alternative dosage regimen may be more effective.