Introduction

Tibial Plateau fractures make up 1% of all fractures and their occurrence is increased in the elderly.  The majority of fractures, up to 70%, are isolated to the lateral plateau. Isolated medial and bicondylar fractures make up the remainder of tibial plateau fractures and are far less common. 

Anatomy

The tibial plateau makes up the superior articular surface of the tibia.  The tibial plateau is separated medially and laterally by the intercondylar eminence and both surfaces are covered by the menisci of the knee.  The medial plateau is larger, concave and significantly stronger then the lateral plateau.  The lateral plateau is smaller, convex and weaker than the medial aspect, leading to an increased number of isolated lateral fractures. 

The tibia bears 85% of the weight load for the lower extremity.  There are 3 attachment sites just distal to the medial and lateral plateau where the muscles of the thigh attach.  Medially, the pes anserinus serves as the attachment point for the sartorius, gracilis, and semitendinosus.  Laterally, Gerdy tubercle is the insertion point for the iliotibial band.  Anteriorly, the tibial tubercle is the attachment point for the patellar ligament. The neurovascular structures that are important are the peroneal nerve laterally and the popliteal vessels posteriorly.   

Mechanism of Injury

The mechanism of injury most commonly associated is a valgus or varus stress coupled with an axial load.  The majority of these fractures result from falls in the osteoporotic and the elderly.  These fractures in younger adults are usually associated with MVA's.

Classification

The classification most commonly used is the Schatzker Classification. 
Type 1 - lateral fracture split
Type 2 - lateral fracture that is split and depressed
Type 3 - lateral depressed fracture
Type 4 - any medial plateau fracture
Type 5 - bicondylar
Type 6 - fracture that demonstrates separation of the metaphysis from the diaphysis 

Presentation/Physical Exam

Patients with tibial plateau fractures most often present with a swollen knee and are unable to bear weight.  The importance of the neurovascular examination should be stressed because of the close proximity of the popliteal artery and the peroneal nerve.  Medial plateau injuries are associated with neurovascular complications more frequently due to the increased force required to cause the injury.  One must also rule out compartment syndrome and check for ligament stability.  As with most fractures one must insure that it is not an open fracture.   

Radiology

AP and lateral x-rays should be obtained along with 40-degree internal and external rotation oblique.  It also may be warranted to get a 10 degree caudally tilted plateau view to evaluate depression.  CT may be needed to evaluate the degree of fragmentation for pre-op planning. 

Differential Diagnosis/Associated Injuries

Tibial plateau injuries are associated with meniscal tears in 50% of patients and 30% of patients have a cruciate ligament injury.  Again, there is risk for neurovascular injury as was discussed in the physical exam section.    

Treatment

Nonoperative treatment is recommended only for slightly or non displaced fractures as well as patients not well enough to undergo a surgical procedure.  The patient should be put in a hinged knee brace and started on early passive range of motion and gradual weight bearing.  The patient should not exceed up to 50 pounds of weight bearing for up to 12 weeks.

Surgery is recommended based on the severity of depression as well as the stability of the knee.  Greater then 2mm of depression is an indication for surgery.  It has also been determined that an increase of 10 degrees or more of knee instability (usually seen with split fractures) as compared to the contralateral side is an indication for surgery.

The primary goal of surgery is to restore the joint surface and then reestablish tibial alignment.  If there is soft tissue injury including ligamentous or meniscal injury they should also be repaired.

Schatzker fractures I-IV can be fixed using percutaneous screws if an adequate reduction can be achieved (less then 1mm step off).  All other fractures should undergo ORIF.

Depressed lesions can be elevated from below the joint surface with a bone tamp through a cortical window.  The residual metaphyseal defect should be filled with bone graft once the joint surface has been repaired.  

All other fractures should use a combination of screws and plates for fracture fixation.  Implant choice will vary based on the fracture pattern.  CT may be useful for pre-op planning to choose the proper implants.  It has also been suggested that arthroscopy can help to determine the extent of injury and thus repair needed, but this has been a debated topic.

Complications

Most common complications are knee stiffness do to the scaring of the components of the knee from the trauma and the surgical dissection.  Also commonly seen is post traumatic osteoarthritis, which can be debilitating since the knee is a major weight bearing joint.

As discussed previously, neurovascular injury is an increased risk because of the close proximity of the structures. As with most ORIF's one must inform patients of the risk of malunion, nonunion, and infection. 

Controversies

Some authors vary on the amount of depression that indicates a surgical need.  The range was from 2mm to 1cm.  However any fracture with 2mm of depression it can be argued that surgery is indicated.