The Lateral Intercondylar Ridge (LIR) gained notoriety with arthroscopic trans-tibial Anterior Cruciate Ligament (ACL) reconstruction where it was mistakenly used to position the ‘over the top’ guide resulting in graft malposition. With anatomic ACL reconstruction some surgeons use the same ridge to define the anterior margin of the ACL femoral insertion in order to guide graft placement. However there is debate about whether this ridge is a consistent and reliable anatomical structure. The aim of our study was to identify whether the LIR is a consistent anatomical structure and to define its relationship with the femoral ACL insertion. In the first part, we studied 23 dry bone specimens. Using a digital microscribe, we created a 3D model of the medial surface of the lateral femoral condyle to evaluate whether there was an identifiable bony ridge. In the second part, we studied 7 cadaveric specimens with soft tissues intact. The soft tissues were dissected to identify the femoral ACL insertion. A 3D reconstruction of the femoral insertion and the surface allowed us to define the relationship between the LIR and the ACL insertion.Background:
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The term ‘resident's ridge’ originated from trans-tibial ACL reconstruction where a bony ridge on the medial surface of the lateral femoral condyle was mistakenly thought to represent the posterior articular margin of the condyle. This was then mistakenly used to position the ‘over the top’ guide resulting in graft malposition. With anatomical anteromedial ACL reconstruction some surgeons use the same ridge to define the anterior margin of the ACL femoral insertion in order to guide graft placement. However there is debate about whether this ridge is a consistent and reliable anatomical structure. There are no anatomical studies that define the features of the ‘resident's ridge’. Therefore, our aim was to identify whether the ‘resident's ridge’ is a consistent anatomical structure in non-operated human cadaveric femoral specimens. Using a digital microscribe, we mapped the medial surface of the lateral femoral condyle in cadaveric human femora denuded of soft tissue. This technique creates an exact 3D model of surfaces and from this we evaluated whether there was an identifiable bony ‘residents ridge’. 23 cadaveric specimens were used.Background:
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