Tests That Predict Septic Hip Arthritis in Children

Doctors must be able to diagnose arthritis-of-the-hip-in-children" class="alinks-link" title="septic hip arthritis">septic hip arthritis in children quickly. Septic arthritis is a painful joint condition caused by a bacterial infection. Without early treatment, permanent damage can occur to the hip. The condition is easily confused with synovitis. Synovitis is an inflammation of the lining of the joint.

Doctors at the Children's Hospital of Philadelphia (CHOP) collected data on 53 children seen at their hospital for hip pain. Septic arthritis was ruled out by doing a hip aspiration. Fluid was removed from the joint and tested for bacteria.

Other tests were done and the results compared once the final diagnosis was made by aspiration. In this way, the doctors could look back and see if other less invasive tests might give an accurate diagnosis. For example, they found that fever was still the best predictor of septic arthritis. No one with synovitis had a fever. Everyone with septic hip arthritis had a fever of at least 99 degrees.

Several blood tests were also helpful. These included C-reactive protein and sedimentation (sed) rate, which are measures of inflammation. Elevated while blood cell count is also a yellow (warning) flag. The study showed that a child with fever, positive blood tests, and unable to put weight on the leg had a 98 percent chance of having septic hip arthritis.

Using statistical analysis, the researchers found that after fever, C-reactive protein was the single best test to use to predict septic hip arthritis. The doctor must combine clinical judgment with test results to make a final decision.