Peri and Post -Operative: Risk Factors

Risk Factors

Orthopaedic surgery patients are at risk of VTE

The risk of VTE in orthopaedic surgery is high in comparison with other surgical disciplines, with associated implications for cost and recovery time1,2

Total knee replacement (TKR):2

Without thromboprophylaxis, the risk of DVT in TKR patients has been documented between 41%–85%

Total hip replacement (THR):2

The risk of VTE in THR patients has been assessed as being between 42%–57%

The risk is not limited to orthopaedic surgery

Observational studies have found a quarter of surgical patients have asymptomatic DVT at post-operative screening3  

- Symptomatic DVT was found in 6% of patients

Symptomatic but non-fatal PE was identified in up to 2% of patients3

- Fatal PE occurred in 0.5% of surgical patients

Major orthopedic surgery4

Patients undergoing major orthopedic surgery represent a group that has a particularly high risk for VTE

VTE prevalence after major orthopedic surgery (unprotected)

VTE prevalence after major orthopedic surgery (unprotected)Deep vein thrombosis (DVT) rates are based on the use of mandatory venography in prospective clinical trials published between 1980 and 2002, in which patients recieved either no prophylaxis or placebo.

Pulmonary embolism (PE) rates were derived from prospective studies that may have used thromboprophylaxis.

Additional risk factors for VTE in surgical patients5

There are certain risk factors which make patients going into surgery more susceptible to developing VTE. Surgical patients and patients with trauma5

  • If total anaesthetic + surgical time >90 minutes or
  • If surgery involves pelvis or lower limb and total anaesthetic + surgical time >60 minutes or
  • If acute surgical admission with inflammatory or intra-abdominal condition or
  • If expected to have significant reduction in mobility or
  • If any other VTE risk factor present

Information on VTE6

  • VTE is a collective term for deep vein thrombosis (DVT) and pulmonary embolism (PE).
  • VTE is a significant cause of mortality, long-term disability and chronic ill-health problems, many of which are avoidable.
  • The incidence of VTE is 1–2 per 1,000 of the population and the risk increases with age.
  • Approximately half of VTE cases are associated with prior hospitalisation for medical illness or surgery.
  • It has been estimated that the management of hospital associated VTE costs the NHS £millions per year

VTE prevention is an important patient safety issue6

1 in 20 people will have a VTE at some time in their life and approximately half of the cases are associated with prior hospitalisation for medical illness or surgery

VTE causes a larger number of deaths than the combined mortality due to:7

  • Breast cancer
  • HIV
  • Road traffic accidents

VTE is the most common preventable cause of in-hospital death8

General risk factors5**

The general risk factors associated with the development of venous thromboembolism (VTE):

  • Active cancer or cancer treatment
  • Age >60 years
  • Critical care admission
  • Dehydration
  • Known thrombophilias
  • Obesity (body mass index [BMI] >30 kg/m2)
  • One or more significant medical comorbidities (e.g. heart disease; metabolic, endocrine or respiratory pathologies; acute infectious diseases; inflammatory conditions)
  • Personal history or first-degree relative with a history of VTE
  • Use of hormone replacement therapy (HRT)
  • Use of oestrogen-containing contraceptive therapy
  • Varicose veins with phlebitis

**For women who are pregnant or have given birth within the previous 6 weeks, please see section 1.16 of NICE NG89.


  1. Falck-Ytter Y et al. Chest 2012;141(2 Suppl):e278S–325S.
  2. Kakkar AK and Rushton-Smith SK. Incidence of Venous Thromboembolism in Orthopedic Surgery. In: Llau JV (Ed) Thromboembolism in Orthopedic Surgery. 1sh ed. London: Springer-Verlag 2013.
  3. Scottish Intercollegiate Guidelines Network (SIGN). Prevention and management of venous thromboembolism. Edinburgh: SIGN; 2010. (SIGN publication no. 122). Updated October 2014. Available at:
  4. Geerts WH, Bergqvist D, Pineo GF, et al. Prevention of venous thromboembolism: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 2008;133 (6 Suppl):381s-453S.
  5. NICE guideline 89. Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism. March 2018. Available at:
  6. NHS England. Commissioning Services that deliver High Quality VTE Prevention. Guidance for Commissioners. Available at:
  7. Dolan G. J R Coll Physicians Edinb 2008;38:338–340.
  8. Cohen AT et al. Lancet 2008;371:387–394.

*Including, but not limited to: congestive cardiac failure (NYHA class III or IV), acute respiratory failure or acute infection, who also have a predisposing risk factor for VTE such as age over 75 years, obesity, cancer or previous history of VTE.~
†In patients with chronic renal insufficiency or acute renal failure.

Fragmin® Guidelines

PP-FRA-GBR-0148.  June 2019