The Use of Flexion Arthrography Computed Tomography Signs (FACTS) to detect minor instability of the lateral aspect of the elbow

Background Recalcitrant lateral elbow pain is often attributed to common extensor tendinopathy, though emerging evidence suggests a potential link with minor elbow instability. The Flexion Arthrography CT Signs (FACTS), including the loose collar sign and capsular tear, may represent intra-articular indicators of such instability. The aim of this study is to evaluate the relationship between recalcitrant lateral elbow pain and the presence of FACTS in patients clinically suspected of having minor lateral elbow instability. Methods A retrospective case-control study was conducted on 130 patients who underwent flexion CT arthrography: 109 patients with clinically suspected minor lateral elbow instability and 21 asymptomatic controls for lateral elbow pain. Radiological findings were assessed for the presence and severity of loose collar signs and capsular tear. Statistical analyses compared the prevalence of these signs between the 2 groups. Results The loose collar sign was identified in 56.9% of cases versus 23.8% of controls (P = .003), while capsular tears were observed in 35.8% of cases versus 9.5% of controls (P = .012). Odds ratios demonstrated that cases were 4.5 times more likely to present annular ligament laxity and 5.6 times more likely to exhibit capsular tear compared to controls. No significant association was found between corticosteroid injections and FACTS. Conclusion FACTS are significantly more prevalent in patients with recalcitrant lateral elbow pain and clinical suspicion of minor instability, supporting their potential diagnostic utility. Flexion CT arthrography may thus serve as a valuable tool in the assessment of minor elbow instability in this patient population.