title: Is DVT prophylaxis necessary after oncology lower limb surgery? A pilot study.
abstract: BACKGROUND
  Deep vein thrombosis (DVT) has been independently associated with both malignant diseases and orthopaedic surgery. Therefore, orthopaedic oncology patients may be at a high risk for thromboembolic events. However, less emphasis is given to this group of patients compared to the patients undergoing total hip and knee replacement. The objective of this study is to determine the incidence of DVT and their risk factors in patients undergoing orthopaedic oncology lower limb surgery without prophylaxis.
  
  
  OBJECTIVE
  (1) What is the incidence of DVT in patients who underwent orthopaedic oncology surgery for the lower limb? (2) What are the risk factors related to DVT in patients who underwent oncology surgery of the lower limb surgery? (3) This is a pilot study to determine if further trial is warranted.
  
  
  METHODS
  This is a prospective study. All sequential patients undergoing orthopaedic oncology operations from the period of 1st October 2013 till 30th September 2014 were recruited for the study with their consent. Their demographic data, diagnosis and surgery were documented. Thirty-eight patients who underwent lower limb surgeries for orthopaedic oncology indications were included in the study. No tourniquet was used in these lower limb surgeries. There were 24 men and 14 women with a mean age of 36 years (11-75). All potential risk factors were also identified and documented. All patients were not given any form of DVT prophylaxis (mechanical and chemical) before and after operation as this is a standard protocol in our center and a Medical Ethics Committee approval was taken for this study. DVT surveillance was performed 1 day before operation and 2 weeks after operation with ultrasound Doppler. Patients diagnosed with DVT via ultrasound Doppler were subsequently scheduled for CTPA to look for pulmonary embolism (PE).
  
  
  RESULTS
  DVT was detected in two patients (5 %). Both patients were asymptomatic and they both had proximal thrombosis. One patient (2.6 %) was diagnosed with non-fatal PE and was asymptomatic. PE was detected incidentally by staging computed tomography scan and the patient had negative ultrasound Doppler of the operated and non-operated limb for DVT. We did not carry out a statistical analysis as the study population with DVT and pulmonary embolism is small.
  
  
  CONCLUSIONS
  The incidence of DVT in patients after undergoing orthopaedic oncology lower limb surgery was low even without prophylaxis at our center. Further investigation with larger sample size is needed to validate our results and identify the risk factors.
  
  
  METHODS
  Level III descriptive study.
authors.affiliation: Department of Orthopaedic Surgery, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Vivek Ajit
authors.initials: VA
authors.lastname: Singh
authors.affiliation: Department of Orthopaedic Surgery, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Lim Ming
authors.initials: LM
authors.lastname: Yong
authors.affiliation: Department of Biomedical Imaging, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Anushya
authors.initials: A
authors.lastname: Vijayananthan