Safety and Efficacy of Intra-Articular Injection of the Hip

The aim of the present study was twofold: a) to establish the therapeutic efficacy of the hip injection with marcaine and steroid; (b) to establish the safety of the procedure with respect to possible bacterial contamination at the time of passage of needle into the hip joint. Thirty-five patients with osteoarthritis of the hip were injected. All patients were admitted as day cases and the procedure was performed in a laminar flow theatre under full aseptic conditions. The hip was aspirated before injection. Aspirate and injecting needles were sent for microbiological examination. Both aerobic and anaerobic cultures were performed.

All patients were followed up for three months after hip injection. Microbiology results were not revealed to reviewing clinicians. All patients were reviewed at two weeks and at twelve weeks.

Thirty-three patients (94.3%) had no growth in the samples. Two cases out of thirty-five hips had a positive culture but none of the patients went on to develop clinical sepsis. Patient response for pain in the hip was graded using a 10 point visual analogue scale (VAS) with 10 point as maximum pain and 0 points as no pain. Pre-injection the patient VAS for pain was a mean value of 6.4 ±0.77 (median, 6). The mean value of VAS score at 2 weeks dropped to 2.6 ±2.7 with median of 2. This difference was highly significant (p=0.003). At 12 weeks mean VAS score was 2.7 ± 2.5 with median value of 2 (p=001). Three patients were worse after the injection.

We found the hip injection to be safe. The risk of bacterial contamination is low provided a strict aseptic protocol is observed. In this study, one third of the patients had excellent pain relief for 3 months after the injection but in two thirds of cases it failed to provide complete, long-term pain relief (> 3 months).