Diagnostic evaluation of open knee injuries: a comparison of arthrography and CT scans.

Purpose: Currently, traumatic arthrotomy of the knee could be diagnosed by saline loading test and computed tomography (CT) which reported excellent sensitivity and specificity. However, there are drawbacks associated with CT, such as cost and radiation hazards. This study aims to evaluate a new diagnostic tool using knee arthrography for individuals with suspected open knee injury and reported sensitivity and specificity using CT scan as the gold standard.

Method: A prospective diagnostic study, involving 43 patients who sustained laceration wounds over the knee, was conducted. The physical examination and conventional radiographic imaging were inconclusive in determining the presence of open joint injury. The established protocol involved directing the patients to undergo a CT scan, which is considered the gold standard for detecting open knee injuries. Subsequently, arthrography of the affected knee was performed. The diagnostic value was subsequently determined based on the outcomes derived from these procedures.

Results: There were 5/43 cases (11.6%) that diagnosed open knee injuries as determined by CT scans. The calculated diagnostic parameters of arthrography derived from these findings are as follows: The sensitivity was 83.3%, the specificity was 96.5%, the negative predictive value was 96.5%, the positive predictive value was 83.3%, the accuracy is 94.3%, the false positive rate is 16.7%, and the false negative rate was 3.4%. Interobserver reliability was substantial (Kappa 0.617). No complication was observed during the arthrography procedure.

Conclusions: Knee arthrography demonstrated high sensitivity, specificity and accuracy for diagnosing open knee injuries, offering a viable alternative to CT scans in certain situations, such as when minimizing radiation exposure is a priority and cost considerations are paramount. Ultimately, careful clinical judgement should guide the choice of diagnostic modality based on individual patient circumstances.