IMPROVED RECOGNITION OF ACL RUPTURES ON MRI USING A 4 POINT CARD

Abstract

Introduction: Rupture of the anterior cruciate ligament (ACL) is a serious injury associated with symptomatic instability of the knee. There is an increasing trend for confirmation of diagnosis with magnetic resonance imaging (MRI) before proceeding to reconstruction. The overall sensitivity and specificity of diagnosis using this modality is more than 95%. It is however observer-dependent. We have developed a simple 4 point recognition card to increase the pick-up rate of this injury for professionals without specific radiological training such as orthopaedic trainees. The aim of this study was to determine how much improvement could be achieved using this card and whether any change was sustained.

Methods: 20 participants (orthopaedic trainees surgeons and medical students) were shown 20 MRI scans of the knee (10 with complete ACL ruptures and 10 with normal ACLs) and asked which scans were demonstrative of ACL pathology. Each participant was then randomly allocated to either having verbal teaching in the standard fashion about detection of ACL injuries [Group 1] or given written cards detailing a 4 point recognition plan for recognising ACL injuries on MRI [Group 2]. A repeat test of MRI scans was performed on each participant immediately after the teaching session and at 3 weeks.

Results: The mean time taken to teach Group A was 14 mins and Group B was 11 mins (p < 0.05). The mean number of correct diagnoses was 2.7/10 in Group A and 3.1/10 in Group B pre-intervention (p > 0.05). Immediately following intervention, there were 6.1 correct diagnoses in Group A and 8.2 in Group B (p < 0.05). At 3 weeks, there were 3.4 correct diagnoses in Group A and 7.9 in Group B (p < 0.05). The difference in number of correct diagnoses at 3 weeks compared to immediately following intervention was significant in Group A (p < 0.05), but not in Group B (p > 0.05).

Conclusions: The results support the use of the 4 point recognition card as to tool for increasing the pick-up of ACL injuries on MRI. It offers advantages over standard teaching Methods: since it takes less time to teach and the necessary information is retained to a greater degree than with traditional teaching methods.