Pain relieving effects of Botox injection in the hip joint following a periacetabular osteotomy.

Patients with symptomatic hip dysplasia may undergo periacetabular osteotomy (PAO) and 10% of these patients have pain >6 months after the operation. An intra-articular lidocaine injection is used to determine if the pain comes from labral pathology in the hip joint or structures around the hip. To allow the patient a longer period of time to test the hip, we wanted to test if an intra-articular injection of Botox combined with local anaesthetic could reduce pain and allow the patient to test the hip. Eleven patients who received a PAO and suffered from persistent pain at least 6 months postoperative had an intra-articular joint injection with 100IE Botox, 3 ml NaCl water and 3 ml lidocaine. Hip pain on the day of injection and after 6 weeks was evaluated using the Visual Analog Scale score, International Hip Outcome Tool (iHOT-12), and Hip and Groin Outcome Score (HAGOS). Botox in the hip joint reduced the pain level and the iHOT-12 score, with a statistically significant improvement 6 weeks after injection. Hip joint injection of a controlled dosage of 100 IU diluted in 3 ml NaCl solution mixed with lidocaine had no side effects in this study with a limited group of patients. Botox has a promising pain-reducing effect on the hip joint in the majority of patients comparable with findings in knee and shoulder joints. Hip joint injection of a controlled dosage of 100 IU, 3 ml NaCl solution mixed with lidocaine had no side effects in this study with a limited group of patients.