Lateral Tibial Condyle

Fig. 14.8. Types of tibial plateau fractures I, split fracture of the lateral tibial condyle II, split fracture with associated depression III, depressed fracture of the lateral tibial plateau IV, fracture of the medial tibial plateau V, bicondylar fracture (can be T or Y shaped) VI, bicondylar fracture with metaphyseal/diaphyseal association...

Sferopoulos NK, Rafailidis D, Traios S, Christoforides J (2006) Avulsion fractures of the lateral tibial condyle in children. Injury 37 57-60... 

The superior tibiofibular joint is a plane oval articulation. The tibial facet lies on the posterolateral aspect of the rim of the lateral tibial condyle. It faces obliquely posteriorly, inferiorly, and laterally. The inferior tibiofibular joint is a syndesmosis. The tibial facet is a rough concave notch into which the convex fibular facet fits. The fibula has a distal articulation with the tibia and the talus at the ankle. 

The anatomy of the ACL in relation to the knee joint architecture. Proximally, it is attached to the posterior aspect of the medial surface of the lateral femoral condyle, passing in front of the PCL and attaching distally on the tibial plateau. 

Plain radiographs provide many indications suggestive of acute ACL rupture avulsion fracture of the lateral tibial plateau, or Segond fracture, which is in fact an injury to the lateral joint capsule, avulsion of the Gerdy s tubercle and a lateral notch lesion, which is a compression fracture of the lateral femoral condyle of more than 2 mm seen on lateral radiograph. A tibial rim lesion on the posterolateral lip of the lateral tibial plateau can also be found alone or associated with the lateral notch lesion and is termed a kissing contusion. Joint effusions can also be detected on simple radiographs (Fig. 20.6). 

The primary motion of the knee joint is flexion-extension rotation around an axis passing through the medial and lateral femoral condyles. The three-dimensional motions of the knee other than flexion-extension rotation are constrained by ligaments, menisci, and articular surface configuration. The biomechanical functions of the ACL are mainly to resist anterior tibial translation, and secondly to resist internal and valgus tibial rotation, or combined motions. 

Fig. 10.6 The proposed noncontact ACL injury mechanism, (a) An unloaded knee, (b) When valgus loading is applied, the MCL becomes taut and lateral compression occurs, (c) This compressive load causes a lateral femoral posterior displacement, probably due to the posterior slope of lateral tibial plateau, and the tibia translates anteriorly and rotates internally, resulting in ACL rupture, (d) After the ACL is tom, the primary restraint to anterior translation of the tibia is gone. This causes the medial femoral condyle to also be displaced posteriorly, resulting in external rotation of the tibia...

However, for those with severely widened tunnels after repeated ACLRs, grafting via over the top of the lateral femoral condyle as well as bone graft behind the revisicMi graft in the tibial tunnel may be considered. 

Anterolateral dislocation is the commonest and is the result of a twisting fall. On an AP radiograph, the head of the fibula is seen almost in its entirety while on the lateral view, it is completely overlaid by the tibial condyle. In posteromedial dislocation, the fibular head is overlaid by the tibial condyle on the AP radiograph but is displaced posteriorly on the lateral view. In superior dislocation, the tibia is foreshortened as a result of a shaft fracture. 

Associated signs of ACL injury are common in children and include lipohaemarthrosis (this may indicate bony injury and a tibial avulsion injury should be exduded), contusion in the lateral femoral condyle and posterior tihial plateau, depression within the lateral condylopatellar sulcus (secondary to impaction of the lateral condyle on the tihial plateau) and Segond fractures (Prince et al. 2005). 

The femorotibial joint consists of two compartments medial and lateral. The medial compartment is composed of the larger medial condyle and the concave superior aspect of the medial tibial plateau and has a wider anteroposterior diameter compared with the lateral one. The lateral compartment is formed by the smaller lateral condyle and the flat or convex articular surface of the lateral tibial plateau. The medial compartment gives stability to... 

Stijak L, Herzog RF, Schai P (2008) Is there an influence of the tibial slope of the lateral condyle on the ACL lesion A case-control study. Knee Surg Sports Traumatol Arthrosc 16 (2) 112-117... 

Several studies have attempted to objectively evaluate the Lachman test by subjective assessment. Lerat et al. [22] examined the anterior/posterior displacement in 563 normal knees and 487 ACL-deficient knees using stress radiography with an anterior load of 9 kg at 20° knee flexion angle, which mimicked the Lachman test. They used the posterior femoral condyle and posterior tibial plateau as reference points on radiography and measured the anterior/posterior translation in both the medial and lateral compartments. Logan et al. [23] investigated the Lachman test... 

Fig.2.6a,b. Lateral knee. Centre On the medial condyle of the knee with a 3-5° cranial angulation along the femur. Area imaged 1o include the whole of the patella and the proximal portion of the tibial tuberosity... 

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