SLR- March 2014- Ansgar Olsen
Reference: Stegeman M, van Ginneken BT, Boetes B, Tuinhout M, Louwerens JW, Swierstra BA. Can Diagnostic Injections Predict the Outcome in Foot and Ankle Arthrodesis? BMC Musculoskelet Disord.2014 Jan 9;15(1):11.
Scientific Literature Review
Reviewed by: Ansgar Olsen, DPM, PhD
Residency Program: Inova Fairfax Hospital
Podiatric Relevance: Intra-articular local anesthetic injections are utilized to localize pain to a joint when considering an arthrodesis procedure for reduction of pain and improvement in function. This study was designed to look at the predictive value of intra-articular injections in improvement in pain and subjective foot function following surgical or conservative treatment.
Methods: Seventy-four patients with the diagnosis of post-traumatic arthritis, osteoarthritis, or rheumatoid underwent fluoroscopically guided injections into primarily hindfoot joints with contrast confirmation of local anesthetic placement. A decision was made by the surgeon to offer surgical or conservative treatment to the patient considering all factors including results of the diagnostic injection. Surgical treatment consisted of arthrodesis of the injected joint. Conservative treatment consisted of shoe gear modification and inlays. Outcomes evaluated were pain measured with a visual analog scale (VAS) and foot function index (FFI) before injection, after injection and at a mean of 3.6 years (2.1 – 4.3 years) following surgical or conservative treatment. A positive injection was deemed to be a decrease of three in the VAS. Data was then organized into four groups: injection positive surgical treatment, injection negative surgical treatment, injection positive conservative treatment, or injection negative conservative treatment. Statistical analysis was then performed using Wilcoxen signed rank tests and Mann Whitney U testing.
Results: Both groups that received surgical treatment (positive injection and negative injection) were found to have statistically significant improvement in VAS atrest (p<.001, .068) and during exercise (p<.001, .046). Statistically significant improvement in both surgical treatment groups (positive injection and negative injection) in FFI disability scores (p<.001, .028) and activity limitation scores (p<.001,.028). No statistically significant improvement was seen in the groups that received conservative treatment. The results of the diagnostic injection were not found to be a statistically significant independent variable when determining outcomes for surgical verses conservative treatment in this cohortof patients.
Conclusions: The authors of this study concluded that diagnostic injection of local anesthetic into joints was not a reliable predictor for outcomes in patients treated with joint arthrodesis or conservative treatment in patients with potential pain of joint origin. Interestingly, patients who underwent arthrodesis did unilaterally better in terms of these measured outcomes than patients receiving conservative treatment. Some limitations of this study were that the results of the injection were not blinded to the surgeons or the patients and that there was no randomization for type of treatment each patient received. If clinical suspicion is high, that pain and loss of function originates from an arthritic joint arthrodesis may result in decreased pain and improvement in subjective function without diagnostic joint injection having to be performed.