A Review of The Current Literature on LMWH Administered at Different Times in Relation to MOS (Major Orthopaedic Surgery): Assessment of The Safety and Efficacy of The Different Proposed Strategies

Nowadays venous VTE represents an important perioperative and postoperative complication in patients undergoing elective Major Orthopedic Surgery (MOS). There are significant discrepancies between clinical practice, international recommendations, and published guidelines. Although thromboembolic events may be less common these days than in the past, they can still lead to serious medical complications. Therefore, most patients undergoing MOS procedures are provided with one of the thromboprophylactic treatments. The optimum timing of LMWH administrations remains debated. Customized structured electronic searches in PubMed and Cochrane database. Meta-Analysis, Randomized Controlled Trials, Systematic Reviews on different strategies of the use of LMWH for MOS. Studies on prophylactic regimens showed that subcutaneous LMWH plays a key role in the management of thromboprophylaxis in MOS. However, some controversies still stand. Among those most relevant, it remains unclear whether to start thromboprophylaxis before or after MOS to better balance the risks of clotting and bleeding. With regards to different times of LMWH administration, there is no convincing evidence that starting prophylaxis 12 hours preoperatively is associated with lower risks of VTE compared to prophylaxis started 12 to 24 hours postoperatively. Furthermore, it seems that the most safe and efficient LMWH regimen is the one called “Just-in-time” (LMWH started 6 hours post-op).