Authors' Reply

We thank Mathews et al. for their thoughtful comments and additional information on the usefulness of diagnostic injection. Mathews et al. audited their practice to see whether positive responses from diagnostic injections were associated with intra-articular pathologic findings. Their results, we believe, support the results presented by Kivlan et al., as well as those presented by Martin et al. In the study by Martin et al. it was found that 41% (20 of 49) of those with a labral tear on an MRI arthrogram did not achieve greater than 50% relief with intra-articular injection. Kivlan et al. noted that 15% (11 of 72) had evidence of intra-articular pathologic conditions during surgery but did not have greater than 50% relief with intra-articular injection. Mathews et al. noted similar results in that 11% (7 of 62) had pathologic intra-articular hip conditions as observed during surgical examination but did not respond to diagnostic injection. The next logical question would relate to the outcome of these 7 individuals. In our clinical practice, we find surgical outcome directly relates to percent relief with diagnostic intra-articular injection. The information presented by Mathews et al., Kivlan et al., and Martin et al. support the belief that pathologic findings identified with imaging or during arthroscopic surgery may not be the primary source of the patient's symptoms. Research studies are needed to see how well diagnostic injection predicts outcome after arthroscopic hip surgery in those with nonarthritic intra-articular hip pain.