ACL rupture and posterior tibial slope - how do we handle this?

Abstract

Aims and Objectives:In recent publications on acl-ruptures and especially on failure of acl reconstruction there comes a strong focus on posterior tibial slope (PTS). ACL reconstructions with a PTS of >12° have an 8 times higher risk of recurrent instability and reconstruction failure. But many questions stay unclear so far-When do we have to correct the tibial slope? How do we correct it? What about simultaneous frontal axis deviations?In this publication a new algorhythm is presented.Materials and Methods:The following aspects have to be evaluatedIs the PTS the only dimension of the deformity or do we have to correct the frontal axis simultaneuosly?Performing a anterior closed wedge extension osteotomy: when do we go distal the tuberosity and when do we perform a tuberosity osteotomy and use it as “bio plating”?Osteosynthesis only screws or always plate?Are there indications for a contineous correction, f.e. with a hexapod?Whats the role of preoperative range of motion of the knee (especially extension)?Always tunnel filling in the same surgery?What about PCL insufficiency and low PTS?Results:An algorhythm is presented giving a treatment path for the different questions mentioned.The procedures are shown step by step in clinical examples and surgery documentation for every pathway.Conclusion:Posterior tibial slope plays an critical role in ACl recontruction. In primary ACl tear a slope correction is probably not indicated.In ACL reconstruction failure a analysis of the PTS needs to be done and correction needs to be discussed.Simultaneuous varus deormities need to be corrected by openwedge valgisation - extension high tibial osteotomy (HTO), while as isolated PTS elevation is subject to an anterior closed wedge extension HTO.Preoperative range of motion needs to be respected not to create hyperextension.Osteosynthesis can be perormed with only screws using the tibial tubercle as “bio-plating”.In cases of former bone-tendeon-bone (BTB) ACL reconstruction a tibial tubercle osteotomy should be avoided and a infratuberositeal osteotomy should be performed and stabilized with plate osteosynthesis.In severe postraumatic cases contineous correction of the slope with fixateur externe, f.e. hexapodes, needs to be performed.