Extensor Mechanism Disruption Impacts Treatment of Dislocated and Multiligament Injured Knees: Treatment and Schenck Classification Recommendations Based on a Global Delphi Method

Background: Multiligament knee injury (MLKI) with associated extensor mechanism (EM) involvement is a rare injury, with limited evidence to guide optimal treatment. The purpose of this study was to identify areas of consensus among a group of international experts regarding the treatment of patients with MLKI and concomitant EM injury. Methods: Utilizing a classic Delphi technique, an international group of 46 surgeons from 6 continents with expertise in MLKI undertook 3 rounds of online surveys. Participants were presented with clinical scenarios involving EM disruption in association with MLKI, classified using the Schenck Knee-Dislocation (KD) Classification. Positive consensus was defined as ≥70% agreement with responses of either "strongly agree"or "agree,"and negative consensus was defined as ≥70% agreement with "strongly disagree"or "disagree."Results: There was a 100% response rate for rounds 1 and 2 and a 96% response rate for round 3. There was strong positive consensus (87%) that an EM injury in combination with MLKI significantly alters the treatment algorithm. For an EM injury in conjunction with a KD2, KD3M, or KD3L injury, there was positive consensus to repair the EM injury only and negative consensus regarding performing concurrent ligamentous reconstruction at the time of initial surgery. Conclusions: In the setting of bicruciate MLKI, there was overall agreement on the significant impact of EM injury on the treatment algorithm. We therefore recommend that the Schenck KD Classification be updated with the addition of the modifier suffix "-EM"to highlight this impact. Treatment of the EM injury was judged to have the highest priority, and there was consensus to treat the EM injury only. However, given the lack of clinical outcome data, treatment decisions need to be made on a case-by-case basis with consideration of the numerous clinical factors that are encountered. Clinical Relevance: Little clinical evidence exists to guide the surgeon on the management of EM injury in the setting of a multiligament injured or dislocated knee. This survey highlights the impact that EM injury has on the treatment algorithm and provides some guidance for management until a further large case series or prospective studies are undertaken.