Heparin Preferred to Compression Stockings After Knee Arthroscopy

In patients undergoing knee arthroscopy, low-molecular-weight heparin (LMWH) for one week was found to be more effective than graduated compression stockings in reducing the occurrence of deep venous thrombosis (DVT) and other vascular complications following the procedure, according to a new study.

Researchers of the University Hospital of Padua (Italy) and other institutions participating in the Knee Arthroscopy Nadroparin Thromboprophylaxis Study Group conducted an assessor-blinded, randomized controlled trial of 1,761 consecutive patients undergoing knee arthroscopy between March 2002 and January 2006, at the Abano Terme Clinic (Italy) and at the University Hospital of Padua. Half of he patients were randomized to wear full-length graduated compression stockings for 7 days, while the other half received a once-daily subcutaneous injection of LMWH (nadroparin) for 7 or for 14 days. The primary efficacy endpoint was the combined incidence of all-cause mortality, asymptomatic proximal DVT, and symptomatic venous thromboembolism. Combined incidence of major and clinically relevant bleeding events was the primary safety endpoint. After the second interim analysis, the data and safety monitoring board of the study prematurely stopped the 14-day heparin group. At the end of the assigned prophylactic regimen, or earlier if indicated, all patients had bilateral whole-leg ultrasonography examinations, and all patients with normal findings were observed for 3 months. None of the patients was lost to follow-up.

The researchers found that in the stockings group, the 3-month cumulative incidence of asymptomatic proximal DVT, symptomatic venous thromboembolism, and all-cause mortality was 3.2%, compared to 0.9% in the 7-day LMWH group and 0.9% in the prematurely stopped 14-day LMWH group. The cumulative incidence of major or clinically relevant bleeding events in the stockings group was 0.3%, compared to 0.9% in the 7-day LMWH group and 0.5% in the 14-day LMWH group. The study was published in the July 15, 2008, issue of the Annals of Internal Medicine.

"Knee arthroscopy carries a definite risk for deep venous thrombosis; however, postsurgical thromboprophylaxis is not routinely recommended,” concluded lead author Giuseppe Camporese, M.D., and colleagues. "We believe that withholding prophylaxis after knee arthroscopy exposes these predominantly young patients to a small but definite risk for venous thromboembolism.”

Knee arthroscopy accounts for approximately 3.5 million procedures per year around the world. Although the rate of objectively proven DVT after knee arthroscopy without thromboprophylaxis has been estimated to be 0.6%-18%, there has been little research regarding the usefulness of thromboprophylaxis for these patients. However, given the lack of research demonstrating a clear benefit for thromboprophylaxis after knee arthroscopy, the American College of Chest Physicians (ACCP) recommends against the routine use of chemical thromboprophylaxis.


Related Links:
University Hospital of Padua
Abano Terme Clinic