Types of posterolateral corner injury associated with both bundle and selective-bundle ACL tears

Background It is unknown whether a selective-bundle tear of the anterior cruciate ligament (ACL) shows a different prevalence of posterolateral corner (PLC) injury than a both-bundle tear. Purpose The prevalence of injury of PLC stabilizer in relation to the type of combined ACL tear (both-bundle and selective-bundle tears) has been investigated. Material and methods This retrospective study included 94 patients who were diagnosed with an ACL tear after knee joint magnetic resonance imaging and underwent arthroscopic surgery. We compared the prevalence of each lesion in relation to the type of ACL injury and the type of selective-bundle tear. We used Fischer exact tests to compare the prevalence of each lesion in relation to the type of ACL injury and the type of selective-bundle tear. Results Both-bundle tears occurred in 55 cases (56%) and selective-bundle tears in 39 cases (44%). The most common PLC injury with an ACL tear was inferior popliteomeniscal fascicle (PMF) injury, followed by superior PMF injury. The prevalence of each PLC injury was higher for both-bundle tears than selective-bundle tears, with the exception of popliteus tendon injury diagnosed by reader 1 (P.H.J). However, these differences were statistically significant for superior PMF injury only (p < 0.05). The prevalence of PLC injury was unrelated to the type of selective-bundle tear (anteromedial vs posterolateral). Conclusion Superior PMF injury is more common in both-bundle tears than selective-bundle tears. There is no statistically significant difference in the prevalence of PLC injury between both-bundle tears and selective-bundle tears.