SCIENTIFIC ARTICLE The posterolateral fluoroscopy-guided injection technique into the posterior subtalar joint: description of the procedure and pilot study on patient outcomes Florian M. Buck & Christian W. A. Pfirrmann & Florian Brunner & Juerg Hodler & Cynthia Peterson Received: 7 August 2011 /Revised: 2 September 2011 /Accepted: 5 September 2011 # ISS 2011 Abstract Objective To describe a posterolateral fluoroscopy-guided injection technique into the posterior subtalar joint and to report patient outcomes 1 month post-injection. Materials and methods Twenty-three consecutive adult patients who underwent fluoroscopy-guided injection into the posterior subtalar joint using a direct posterolateral approach and who returned an outcomes-based postal questionnaire after receiving this injection were included. Numerical pain rating scale (NRS) data were collected prior to injection. NRS and Patient’ s Global Impression of Change (PGIC) scales were completed 1 day, 1 week, and 1 month after injection. The proportion of patients who improved was calculated for each time period. Baseline NRS data were compared to each time point using the Wilcoxon test to assess differences. Spearman’ s correlation coefficient was used to compare the 20 min NRS score with all follow-up NRS scores. All available images were reviewed for the presence of subtalar osteoarthritis (OA). Patient charts were reviewed to identify characteristics of patients referred for subtalar injections. Risk ratios were calculated comparing presence of OA or other abnormali- ties with improvement. Results A posterolateral approach for fluoroscopy-guided injections into the subtalar joint is described. There was a significant reduction in the mean NRS score at all time periods compared to baseline (p ≤ 0.004). One-third of patients (7/21) reported clinically relevant improvement at 1 month. Conclusions Fluoroscopy-guided puncture of the posterior subtalar joint using a posterolateral approach is possible. Clinically significant improvement is reported in 33% of patients after 1 month. Keywords Arthrography . Foot . Posterior subtalar joint . Intraarticular steroid injection Introduction Diagnostic or therapeutic injection procedures into the foot region have been used for many years to help diagnose a particular joint as a pain source or to provide treatment to a painful articulation [1–6]. Studies have shown that injec- tions performed using imaging guidance (fluoroscopy, ultrasound, or CT) more accurately deliver the medications to the desired target joint compared to injections using palpation alone [1, 3–11]. The posterior subtalar joint is one of the most typically injected foot articulations [10–15]. There are various techniques described in the literature for injecting medica- tion into this joint, including the anterolateral, poster- omedial, lateral oblique, and posterolateral approaches [10–13, 15]. Previously the anterolateral approach was claimed to be the best for injecting the posterior subtalar F. M. Buck : C. W. A. Pfirrmann : C. Peterson Radiology, Orthopedic University Hospital Balgrist, Zurich, Switzerland F. Brunner Rheumatology, Orthopedic University Hospital Balgrist, Zurich, Switzerland J. Hodler Department of Radiology, University Hospital Zurich, Zurich, Switzerland F. M. Buck (*) Uniklinik Balgrist, Forchstrasse 340, CH-8008 Zurich, Switzerland e-mail: pixdoc@gmail.com Skeletal Radiol DOI 10.1007/s00256-011-1278-0