Role of anticoagulant therapy in Orthopaedics

Deep vein thrombosis (DVT) & pulmonary embolism (PE) are known together as venous thromboembolism (VTE). Venous thromboembolic events are common & potentially life-threatening complications after trauma & Orthopaedic surgery.

Of all the patients, Orthopaedic patients are at higher risk for DVT and VTE. The pathophysiology of Thromboembolism (Click here for more details) can be explained by the well known Virchow’s triad
-Endothelial injury,
-Stasis of blood flow &
-Hypercoagulability.
In an orthopaedic case undergoing a surgery, all the criteria of Virchow’s triad can be found:
a)Tourniquet use during surgery, immobilization & bed rest (Blood stasis);
b) Surgical incision & manipulations of the limb (Endothelial injuries);
c) release of thromboplastin agents after trauma, & use of bone cement (PMMA) (Hypercoagulability).

Risk Factors for DVT in Trauma & Orthopaedic Patients:

• General factors: age, obesity, varicose veins, family history of VTE, thrombophilias, combined oral contraceptives, hormone replacement therapy, anti-oestrogens, pregnancy, puerperium, immobility, immobility during travel, hospitalization, anaesthesia & central venous catheters.
• Trauma & Orthopaedics: Pelvic & lower extremity fractures, hip or knee replacement, arthroscopic knee surgery, major trauma and spinal cord injury (SCI) head injury, major general surgery, & prolonged immobilization

Risk factors for VTE act in a cumulative manner & hence, in patients with orthopaedic trauma & those undergoing orthopaedic surgery, VTE prophylaxis are recommended according to the guidelines.

Prophylaxis of VTE in orthopaedic patients(Click here for more details) can be achieved by:
A. Chemical Prophylaxis i.e. Anticoagulant Therapy
B. Mechanical Prophylaxis, e.g. Graduated compression stockings (GCS), Sequential pneumatic compression devices (PCDs)/Intermittent pneumatic compression(IPC) devices, & Pneumatic plantar (A-V) foot pumps
C. Vena Cava Filters(VCFs)– Permanent VCF & Retrievable VCF

Anticoagulant therapy is the mainstay of medical treatment for Venous thromboembolism (VTE) with its advantage of being noninvasive, a low risk of complications, & an improvement in morbidity & mortality.
Anticoagulant drugs in use are:-
–Low Dose Heparin: Unfractioned Heparin
–Low Molecular Weight Heparin (LMWH): enoxaparin, dalteparin, nadroparin, tinzaparin, & ardeparin
–Fondaparinux
–Rivaroxaban
–Dabigatran
–Warfarin
–Aspirin

thromboprophylaxis following total hip replacement

Total hip replacement is … which needs thromboprophylaxis to prevent Venous thromboembolism.
For VTE prophylaxis in major orthopaedic surgery, many guidelines are available worldwide, published from the ACCP (2012), AAOS (2011), SIGN (2010, updated in 2015) & the National Institute for Health and Care Excellence (NICE) (2018).

Current ACCP guidelines(2012)

➨The current ACCP guidelines recommend the use of low molecular weight heparin(LMWH), low-dose unfractioned heparin(UFH), Vitamin-K antagonists(VKA), fondaparinux, apixaban, dabigatran, rivaroxaban, aspirin or IPCD. The use of LMWH is preferred over the other recommended agents.
➨When LMWH is used for VTE prophylaxis in patients undergoing total hip replacement, it is recommended to start either 12 hours or more pre-operatively or 12 hours or more post-operatively.
➨Duration of anticogulant treatment: for minimum 10 to 14 days & up to 35 days extension has been suggested on outpatient basis.

➨For hospitalized petints, the dual prophylaxis– mechanical prophylaxis using an IPCD device for at least 18 hours daily along with chemical prophylaxis by an anticoagulant drug is recommended.

➨For uncooperative patients who refuse for injections or/& IPCD, the alternatives are apixaban, dabigatran or rivaroxaban.

➨Pharmacologic treatment is contraindicated in patients with major bleeding risk.

➨It is suggested against using IVC filter for primary prevention over no prevention in patients with increased bleeding risk or contraindications to both pharmacologic & mechanical thromboprophylaxis.

AAOS guidelines(2011)

➤Discontinuation of anti-platelet agents (aspirin, clopidogrel, etc.) pre-operatively
➤Risk assessment: PE & major bleeding
➤Start pharmacological thromboprophylaxis with/or mechanical compressive devices in patients not at risk after total hip replacement
➤If contraindications to anticoagulation: consider vena cava filter
➤Intraoperative & IPO mechanical prophylaxis
➤consider regional anaesthesia
➤Postoperative- continue mechanical prophylaxis until discharge to home
➤Mobilize the patient as soon as feasible.
➤a strong recommendation against routine duplex ultrasonography screening postoperatively in asymptomatic patients
➤No clear guideline about duration of treatment.

SIGN guidelines(2010, updated in 2015)

⯁They recommend the use of pharmacological prophylaxis (LMWH, fondaparinux, rivaroxaban or dabigatran) combined with mechanical prophylaxis unless contraindicated
⯁No clear recommendation of duration of treatment.

NICE guidelines(2018)

⯈LMWH for 10 days followed by aspirin for another 28 days or
⯈LMWH for 28 days along with anti-embolism stockings until discharge for patients undergoing elective THR
⯈ Rivaroxaban, apixaban or dabigatran are also recommended by NICE guidelines as alternatives for the prevention of venous thromboembolism in adults undergoing elective THR.

Read the following articles for details:
👉Thromboembolism prophylaxis in orthopaedics: an update

👉Thromboprophylaxis and Orthopaedic Surgery: Options and Current Guidelines

👉Deep Vein Thrombosis Prophylaxis in Trauma Patients