Thrombin has many biological properties similar to those of growth factors. In a previous study, we showed that thrombin improves healing of the rat tendo Achillis. Low molecular weight heparin (LMWH) inhibits the activity and the generation of thrombin. We therefore considered that LMWH at a thromboprophylactic dose might inhibit tendon repair. Transection of the tendo Achillis was carried out in 86 rats and the healing tested mechanically. Low molecular weight heparin (dalateparin) was either injected a few minutes before the operation and then given continuously with an osmotic mini pump for seven days, or given as one injection before the operation. In another experiment ,we gave LMWH or a placebo by injection twice daily. The anti-factor Xa activity was analysed. Continuous treatment with LMWH impaired tendon healing. After seven days, this treatment caused a 33% reduction in force at failure, a 20% reduction in stiffness and a 67% reduction in energy uptake. However, if injected twice daily, LMWH had no effect on tendon healing. Anti-factor Xa activity was increased by LMWH treatment, but was normal between intermittent injections. Low molecular weight heparin delays tendon repair if given continuously, but not if injected intermittently, probably because the anti-factor Xa activity between injections returns to normal, allowing sufficient thrombin stimulation for repair. These findings indicate the need for caution in the assessment of long-acting thrombin and factor Xa inhibitors

The Hospital (Trust) guidelines generally recommend 40mg of Low molecular weight heparin (LMWH) twice daily (BD) for all patients over 100kg for those undergoing total hip (THR) and knee replacements (TKR) respectively. British National Formulary (BNF) recommends 40mg of LMWH once daily (OD) for all patients regardless of their overall weight or body mass index (BMI). We evaluated the outcome of prophylactic LMWH dosage for patients undergoing THR and TKR by monitoring surgery related venous-thromboembolic events up to a minimum of three months after surgery. A retrospective audit was carried out after obtaining institutional approval and all consecutive elective patients weighing over 100kg and undergoing THR and TKR were included. All patients were followed up for a minimum of 3 months after their operation to investigate the dose of prophylactic LMWH received, and whether they had developed any venous thromboembolic events (VTE) post operatively. This was done using a combination of electronic notes, drug charts and deep venous thrombosis (DVT) or computed tomography pulmonary angiogram (CTPA) reports on the hospital/trust database. A total of 53 patients underwent elective THR (18) and TKR (35) between the period of March 2017 and September 2017. Forty-four patients received 40 mg OD and 9 patients had 40 mg BD. None of the patients developed a confirmed DVT or pulmonary embolism in the 3 months following surgery regardless of the dose received. We demonstrate that there is no clinical benefit in having patients over 100kg on twice daily LMWH with the aim of preventing post-op thromboembolic complications. This conclusion is in line with the BNF recommendations for VTE prophylaxis

Low molecular weight heparin (LMWH) is frequently used as thromboprophylaxis after major orthopaedic surgery. Varying levels of non-adherence (5% to 45%) with outpatient LMWH has been reported. Oral direct thrombin inhibitors have been recommended by industry due to ease of administration. We aim to audit the compliance rate with outpatient LMWH treatment following primary total hip arthroplasties (THA) in our district general hospital (DGH). Using the ORMIS computer system, we identified all primary THA performed in Monklands Hospital between July 2011 and August 2012. Patients’ case notes were analysed retrospectively, looking at operating surgeon's postoperative thromboprophylaxis instructions. We then conducted a telephone interview on patients discharged with outpatient LMWH to assess compliance. There were 58 primary THAs performed during the audit period. 33 patients were discharged on outpatient LMWH, whilst 15 patients and 3 patients were discharged on aspirin and warfarin respectively. Seven patients were excluded as their discharge prescriptions were missing. We successfully contacted 20 of the 33 patients discharged with outpatient LMWH. All respondents showed 100% compliance to the full course of treatment. 50% of patients self-administered; 30% were administered by district nurses and 20% by family members. 35% of patients preferred an oral tablet alternative, for its perceived ease of administration. Bruising and skin irritation were the reported problems in some patients, but these did not affect compliance. Contrary to the previous published non-adherence rates, the compliance rate with outpatient LMWH after THA was high in our DGH. The patient counseling, and family/district nurse involvement in may have contributed to this. However, our numbers of patients are low but data collection continues

Objectives

To review the current best surgical practice and detail a multi-disciplinary approach that could further reduce joint replacement infection.