Comparison of Two Injection Techniques for Intra‐articular Hip Injections

Objectives Intra‐articular hip joint injections have traditionally relied on the use of image guidance to confirm intra‐articular needle placement. Musculoskeletal ultrasound (US) has emerged as a popular tool to aid the clinician in performing intra‐articular hip injections. Modern automated injection delivery systems are commercially available and may offer the potential to optimize clinical efficiency while limiting procedural morbidity. The purpose of this study was to compare patient‐reported outcomes and clinical efficiency between two US‐guided intra‐articular hip injection techniques. The hypothesis was that the use of an automated delivery system for US‐guided intra‐articular hip joint injections would show superiority in clinical efficiency over traditional syringe injections. Methods This study was a level 1 randomized prospective postmarket clinical evaluation. Forty patients were randomly assigned to undergo a single intra‐articular corticosteroid injection of the hip using either an automated delivery system (Navigator Delivery System; Carticept Medical, Inc, Alpharetta, GA) or a traditional syringe injection. Enrolled patients were prospectively followed at 1, 6, and 12 weeks after injection. A battery of patient‐reported outcomes were collected at baseline and again at 1, 6, and 12 weeks after injection. Preparation times were documented for all injections. Results Forty patients met inclusion criteria and were enrolled. Twenty patients were randomly assigned to receive US guided intra‐articular hip injections using the automated system (group A), and 20 patients were treated with standard syringe injections (group B). Body mass index, smoking history, symptom duration, baseline patient‐reported outcomes, and demographic data were similar between groups. Improvements from baseline scores were noted at all time points for all patient‐reported outcomes regardless of the injection technique used. However, no significant differences were noted at any time point for any of the patient‐reported outcomes based on which injection delivery system was used. Statistically significant differences were noted at 6 and 12 weeks for the subjective global assessment score, which favored the use of the automated delivery system over the standard injection technique (6 weeks, P = .029; 12 weeks, P = .028). Between the two injection procedures, there was no difference in pain experienced by the patient (mean Visual Analog Scale pain score ± SEM: group A, 34.9 ± 6.49; group B, 34.5 ± 5.99; P = .960). Body mass index did not influence pain associated with an intra‐articular hip injection ( P = .870); however, younger patient age was found to be an independent predictor of increased pain associated with injection ( P = .011). Although there were no differences among male or female patients in hip injection pain based on the delivery method, statistically significant differences were encountered between male and female patients, irrespective of treatment assignment (male/female: group A, 25.1/41.4; group B, 26.7/46.1; P = .049). Among patients with a smoking history, large differences were noted for injection pain when data for both groups were pooled, regardless of the delivery method (no history, 30.0 ± 4.86; smoking history, 40.8 ± 9.94). Clinical efficiency (as measured by injection preparation time) was found to be inferior for the automated system compared to traditional syringe injection ( P < .0001). Conclusions Use of an automated delivery system for US‐guided intra‐articular hip injections did not show superior efficiency or patient comfort over traditional syringe injections. Intra‐articular corticosteroid injections led to clinically and statistically significant improvements in pain and function for patients with intra‐articular hip pain, irrespective of the delivery method. Smoking history and female sex were independent predictors of increased pain associated with intra‐articular hip joint injections.