The winner of the 2021 Knee Society John N. Insall Award is a research paper by orthopedic surgeons and researchers from Hackensack Meridian Hackensack University Medical Center which was published in a recent supplement of The Bone & Joint Journal.
John Nevil Insall (1930–2000) was a pioneering English orthopaedic surgeon who contributed extensively to the advancement of total knee replacement surgery. He designed four models of widely used systems. The Insall Award was established to honor Dr. Insall’s achievements and contributions to orthopaedics. This award recognises outstanding papers concerning clinical results and techniques.
This year’s winning research team were able to find clear evidence that aspirin is effective against infrapopliteal deep vein thrombosis (IDVT), blood clots found in the calf muscle, following total knee replacement (TKR). The team also found that aspirin use is associated with a low rate of clot progression and stroke or thromboembolic events.
“DVTs are serious because blood clots can loosen and lodge in the lungs. The optimal management of an infrapopliteal deep venous thrombosis, located in veins below the knee, following total knee arthroplasty has never been clear-cut for the clinicians managing postoperative care,” said Gregg R. Klein, M.D., the paper’s corresponding author and physician associate, vice-chairman, Department of Orthopedic Surgery, Hackensack University Medical Center, and associate professor, Department of Orthopedic Surgery, Hackensack Meridian School of Medicine.
“This study, to the best of the authors’ knowledge, is the first to show that patients undergoing total knee replacement who developed blood clots below the knee can be effectively treated with aspirin. While the optimal management of these types of clots following knee replacement surgery needs further prospective study, treatment with aspirin could be a new standard of care in orthopedics.”
The researchers organized a retrospective analysis of patients diagnosed with infrapopliteal deep vein thrombosis following TKR, looking at medical records of those who had received primary or revision arthroscopy between January 1, 2014 and January 1, 2019 at one institution. Patients who were treated surgically during the study received DVT prophylaxis, early mobilization, mechanical prophylaxis, and prophylaxis with aspirin, heparin, or warfarin based on their risk profile.
“Of the total group of 532 patients who had infrapopliteal deep vein thrombosis (out of 5,078 who were treated with total knee replacement), 91% were treated with aspirin twice daily for three months,” wrote the authors. “The other patients with IDVT were treated with anticoagulants other than aspirin. Follow up ultrasound was performed on 94% of the patients with IDVTs treated with aspirin, and 2% showed propagation of the infrapopliteal deep vein thrombosis. Overall, the rate of pulmonary embolism in the patients with infrapopliteal deep vein thrombosis s who were treated with aspirin was 0.2%, representing one patient.”
The authors caution that “the risk of infrapopliteal deep vein thrombosis propagation and symptom progression must be balanced against potential hemorrhagic complications associated with administration of anticoagulation therapy. The researchers conducted a retrospective analysis of a group of patients diagnosed with IDVT following total knee replacement who were treated with aspirin, followed closely for development of symptoms, and scanned with ultrasound to determine resolution of infrapopliteal deep vein thrombosis.”
So what makes this research truly special?
“This study shows orthopedic surgeons can safely treat below knee DVTs with aspirin,” said Dr. Klein to OTW. “Some physicians have historically advocated for the use of strong anticoagulant medications to treat these below knee DVTs. These medications carry significant risk for bleeding and hematoma formation and have been shown to be associated with a higher rate of infection. Although it is a viable option we still need to study this further with a larger randomized study. However at this time it appears reasonable to treat these type of clots with aspirin.”
