Accuracy of Ankle Intra-articular Injections

Purpose: Blind intra-articular injections (BIAI) of various joints are performed for diagnosis and treatments of different pathologies in sport medicine, rheumatology, general practice and orthopaedics. The gold standard for any joint injection is image guidance but studies have shown higher accuracy for BIAI. Objective of this study was to evaluate the intraoperative success and accuracy of ankle joint intra-articular injections. Materials and Methods: A total of 100 patients were assessed. Mean age was 34.11 years (range 18 to 80). Three orthopaedic surgeons of a variable skill level carried out all ankle joints insufflation with a 14G sterile needle and physiological saline. The result was recorded as positive when a back flow of saline was seen during the insertion of the arthroscopic trocar, indicating that the joint capsule was breached. If no back-flow of saline was seen, this was recorded as a negative result. No further attempts to re-position or re-apply the needle were made if unsuccessful at the first attempt. Statistical analysis was performed using SPSS software version 21.0 (IBM Corp. 2012). Data was organised into contingency tables and analysed with Fishers’ exact test (two-sided, 95% confidence interval). Results: In total 78 male and 22 female patients were included in the study. Of the 100 injections performed 63 were intra-articular (translating to an accuracy rate of 63%). The pre-operative diagnosis affected the accuracy. This was found to be significant (p<0.0001). The side of surgery also affected the accuracy and this was also found to be significant (p<0.02). Conclusion: The results of this study have demonstrated that blind intra-articular injection of the ankle joint is not incredibly accurate. Despite the high skill level of an experienced foot and ankle surgeon, only 63% of injections were placed successfully into the ankle joint. This study therefore stresses the importance of using image guidance when performing ankle joint injections for diagnostic and therapeutic reasons. Levels of evidence: Level III