Diagnostic value of intra-articular anaesthetic hip joint injection in patients with atypical hip pain: a systematic review

Abstract

Purpose: Pain in the hip region can arise from different sources. These include intra-articular hip joint pathologies such as osteoarthritis, acetabulofemoral impingement, labral pathology as well as extra-articular causes such as greater trochanter pain syndrome, inguinal hernia, and referred or radicular pain from the lumbosacral spine. Although with careful history and examination hip osteoarthritis can often be distinguished from other origins, sometimes symptoms are atypical. In these cases, when total hip replacement surgery is being considered, an intra-articular anaesthetic hip injection is frequently used as a diagnostic tool for excluding or confirming an intra-articular source of hip pain. To assess the diagnostic value of intra-articular anaesthetic hip injection in patients with atypical hip pain. Methods: Searched databases were PubMed, Embase, PEDro and the Cochrane Library (until December 2011). Included were cohort studies, randomized controlled trials and case series assessing the diagnostic value of anaesthetic hip injections in differentiating between hip pain caused by osteoarthritis or another source in patients with atypical hip pain. Key terms used were: “osteoarthritis”, “hip”, “spine”, “diagnostic” and “intra-articular”. Two reviewers independently selected studies for inclusion, extracted data and assessed methodological quality. Depending on homogeneity of the studies, we calculated pooled estimates of sensitivity and specificity with 95% confidence intervals (CI). Positive effect of total hip replacement surgery after a positive test and positive effect of spinal treatment after a negative test were used as reference test. Additional calculations were done for a total hip replacement-only scenario. Methodological quality of the studies was assessed with the Quadas2 tool. Results: The search yielded 1387 eligible studies. Finally, 9 articles were included representing 556 patients with hip pain; seven studies were included in the meta-analysis. The studies were heterogeneous as to patient characteristics and outcome measurements. The pooled estimates of sensitivity and specificity were .97 (95% CI .87, .99) and .91 (95% CI .83, .95). This corresponds with a positive likelihood ratio of 10.6 (95% CI 5.6, 20.1) and a negative likelihood ratio of 0.04 (95% CI 0.01, 0.15). The total hip replacement-only scenario contained patients who had received a total hip replacement and their pain outcome was scored afterwards. The pooled estimates of sensitivity and specificity were .96 (95% CI .87, .99) and .42 (95% CI .09, .84). Conclusions: These results show that complete or partial hip pain relief after intra-articular anaesthetic hip injection is reasonably predictive of pain relief after total hip replacement surgery. However, the value of a negative test (no pain relief after hip injection) is unclear. As our results may have been influenced by heterogeneity and missing data, the evidence for the diagnostic value of an intra-articular anaesthetic hip injection is not conclusive.