Importance: Open in situ subtalar arthrodesis (ISTA) has been a standard procedure for treating subtalar arthritis for varied etiologies with good outcomes. There has been a paradigm shift from ISTA to arthroscopic subtalar arthrodesis (ASTA) over the past two decades due to increase in number of surgeons performing arthroscopy worldwide. However, there is only limited evidence in the existing literature to substantiate the benefit of this change with regards to patient benefit. To our knowledge, there are also no systematic reviews comparing the results of the two techniques for subtalar arthrodesis (STA).
Our systematic review aims to determine the superior technique for performing STA by comparing the outcomes, union rates, and complications between open and arthroscopic approach for in situ STA. We hypothesised that both procedures would have similar outcomes, union rates, time to union, and complication rate for in-situ STA.
Evidence review: Three databases, MEDLINE/PubMed, the Cochrane Library, and Google Scholar, were searched using predefined inclusion and exclusion criteria to compare the two procedures. Risk of bias assessment was done using The Risk of Bias in Non-randomised Studies of Interventions (ROBINS-I) tool for assessing the risk of bias in the included studies. Weighted mean averages were computed for all parameters and tabulated separately for ASTA and ISTA.
Findings: We included a total of 22 studies with a total of 978 (ASTA-310, ISTA-668) patients in the review. The most common indication for both techniques was post traumatic subtalar arthritis due to malunited calcaneal fracture in both groups (54.5%). The American Orthopaedic Foot & Ankle Society score was better in the ASTA group with a weighted average improvement of 43.4, while the weighted average improvement was 31.1 in the ISTA group, respectively. Patients undergoing ASTA had a weighted average union rate of 95.5% (standard deviation [SD]-3.6) with a weighted average time to union of 12.2 weeks (SD-2.4) while the ISTA group reported 90.7% (SD-6) union rate with a weighted average time to union of 15.5 weeks (SD-8.4). The weighted overall average complication rate was 13.1% (SD-8.9) in ASTA group and 20.3% (SD-16.2) in the ISTA group with hardware-related complications being the most common in both the groups.
From the existing literature, our review suggests that both ASTA and ISTA techniques are effective procedures for STA. However, there is no conclusive evidence to recommend one technique over another. High quality randomised studies may be further required to clearly define the superiority of one technique over another.