Hip injection using sonography could help surgeons to give a more precise information of the origin of groin pain.
Failure cases of hip arthroscopy actually exist, and one of the most concerned problems is misdiagnosis of the cause of groin pain. Even if there is no remarkable finding in radiograph, MRI often reveals intraarticular pathology such as acetabular labral tear, and arthroscopic treatment is chosen. However, arthroscopic treatment is sometimes ineffective in spite of the proper approach to intra-articular lesion. Hip disorders include intra-articular pathogy and extra-articular pathology. These pathologies are not always independent, but co-exist or dependent on each other. In addition to imaging evaluation, we check the effect of intra-articular injection. If the intra-articular injection is effective, conservative treatment is preceded. If the intra-articular injection is ineffective, we try extra-articular injection and rehabilitation such as stretching around pelvis. The purpose of this study is to review the patients who underwent conservative treatment including hip injection with sonography to reach a more reliable diagnosis of hip disorders.
43 patients with 43 hips whose torn acetabular labrum were suspected were included in this study. Conservative treatments including hip injection to intra/extra-articular lesion using sonography, medication, and/or rehabilitation was preceded. Injection was performed with a mixture of 3 ml of 1% mepivacaine, 7ml of saline, and 0.5 ml of dexamethasone. The HI VISION Avius ultrasound system (Hitachi Aloka Medical, Tokyo, Japan) with a 14-6 MHz linear probe was used. Extraarticular injection was performed via anterior approach targeting intermuscular space around iliopsoas above the anterior capsule or rectus femoris. As for the rehabilitation program, muscle exercise around hip, core strengthening, and spinopelvic stretching were educated. The mean age of the patients was 48 years (29-81 years). Effectiveness of each injection and effective duration were investigated.
Both intraarticular and extraarticular injection were performed in 25 patients, and only extraarticular injection in 18 patients. Both intraarticular and extraarticular injection were effective in 23 patients out of 25 patients, and extraarticular injection was more effective in 10 patients. In total, extraarticular injection was effective in 36 patients out of 43 patients. In these patients, 22 patients were followed up more than 6 months, and effective duration was within 1 week in 4 patients, more than 2 weeks in 12 patients, and more than 4 weeks in 6 patients. 15 patients significantly improved and do not need further hip injection.
From this study, even if intraarticular lesion is detected by radiograph or MRI, extraarticular lesion should be ruled out. Hip injection using sonography could help surgeons to give a more precise information of the origin of groin pain, which leads to select optimal treatment of groin pain and operative indication for hip arthroscopy.