Does Thinning the Blood During Surgery Prevent Blood Clots Following Total Knee Replacement Surgery

Multi-centre, Double-blind, Randomized, Controlled Trial Comparing Intra-operative Regional Heparinization to Placebo for the Prevention of Deep Vein Thrombosis Following Total Knee Arthroplasty

The goal of this study is to prevent blood clots from forming during surgery and a few days after total knee replacement surgery. This study will help us identify whether using a blood thinner in the operating room will stop blood clots from forming during the operation.

Venous thromboembolism is a major cause of morbidity and mortality after lower limb orthopaedic surgery in the adult patient. If, as suggested, DVT formation begins intra-operatively then targeting this period to prevent clot formation could substantially reduce DVT rates in the TKA population. The present study aims to determine whether this intra-operative regional heparinization technique is effective in preventing the intra-operative formation of DVT following TKA, as evidenced by venography in the early post-operative period.

Inclusion Criteria:

1. Undergoing unilateral primary total knee arthroplasty
2. Males and non-pregnant females ages 18-90 (pre-menopausal females will undergo a serum pregnancy test at screening)
3. Full weight bearing status (of non-operated leg) following surgery
4. Patient able to understand and willing to sign informed consent

Exclusion Criteria:

• 1) Known hypersensitivity to contrast media 2) Patients taking Metformin 3) Serum creatinine above 180Fmol/L 4) Platelets < 100 x 10 9/L, INR/PTT > 1.5 x normal 5) History of heparin induced thrombocytopenia 6) Allergy to heparin or fish 7) Prior use of protamine sulfate (i.e., protamine-containing insulin) 8) Vasectomized or infertile males 9) History of bleeding disorder 10) Bilateral total knee arthroplasty 11) History of stroke or myocardial infarction in previous 6 months 12) Traumatic spinal anaesthesia (two or more attempts and/or bloody) 13) History of previous DVT/PE 14) Active peptic ulcer disease (e.g., GI bleed, rectal bleed) 15) Currently on chronic anticoagulant therapy 16) Contra-indication to heparin 17) Patient is taking part in any other investigational study 18) Previous contralateral TKR or hip replacement