Abstract
Introduction:
Measurement of ankle brachial pressure index is an easy screening test to perform in patients presenting with an acute knee injury. According to Nicardi et al recognition of vascular injury is particularly challenging because vascular compromise may not be immediately associated with clinical signs of ischemia.
The aim of the study is to correlate the values of ABPI measurements to CT angiograms and clinical outcome in high energy knee trauma.
Materials and Methods:
We reviewed the records of patients admitted to our unit following high energy knee trauma during the period Nov 2012 to Dec 2013. The orthopaedic injuries sustained were 11 knee dislocations, 5 supracondylar femur fractures, 3 high energy tibia plateau fractures (Schatzker 5 and 6) and 4 gunshot injuries.
From the records we recorded the nature of the orthopaedic injury, the ABPI, the CT angiogram and the clinical outcome. We excluded all patients with insufficient records and previous vasculopathy. After these exclusions, 23 patients were enrolled for the study.
Analysis of the data involved calculating of basic descriptive statistics, including proportional and descriptive measures. T-tests (one-sample and independent) and chi-square tests of independence were employed to investigate the relationship between ABPI and CT angiogram and clinical outcomes. Throughout the statistical analysis cognisance is taken of the relative small sample, and relevant test adjustments made.
Results:
A total of 5 of the 23 patients had a significant vascular injury that required vascular intervention. Three patients underwent vascular repair and orthopaedic fixation. One patient had an occult vascular injury and presented with a necrotic limb three days after admission. His delayed CT demonstrated arterial cut off. This patient later went on to have an amputation. The fifth patient presented 12 days post knee dislocation with reduced pulses but the leg was still viable.
In these five patients the ABPI value ranged from 0.3 to 0.65. In the remainder the ABPI ranged from 0.91 to 1.4. These 18 patients had a CT angiogram with normal flow and no intimal tears.
Conclusion:
In all the patients with vascular sequelae from high energy knee injuries and dislocation the initial ABPI measurement performed well as a screening test for vascular injuries.
It can therefore be recommended as a practical investigation in the initial evaluation of knee injuries that has cost and time saving benefits.
