Femoral condyle fractures

Anatomical Relation to Femoral Condyles

The cruciate ligaments stabilize the knee joint in the sagittal plane, connecting the femur (femur) to the tibia (tibia). Their name derives from their crossing course within the joint cavity.

• Anterior Cruciate Ligament (ACL, Anterior cruciate ligament): originates from the posterior part of the intercondylar notch at the lateral femoral condyle. It courses anteriorly and medially, attaching to the anterior part of the tibial plateau. It is conventionally divided into anteromedial (tensed during flexion) and posterolateral (tensed during extension) bundles. The ACL has an extremely low potential for spontaneous healing and contains important proprioceptive mechanoreceptors.
• Posterior Cruciate Ligament (PCL, Posterior cruciate ligament): originates from the medial surface of the medial femoral condyle and attaches to the posterior surface of the tibia below the joint line. It is a stronger structure, withstanding loads of up to 3000 N. It consists of anterolateral and posteromedial bundles. Unlike the ACL, this ligament is capable of repair in partial tears.

Interestingly, the predominantly vertical course of these ligaments is biomechanically suboptimal for blocking anterior-posterior tibial translation; however, this precise spatial orientation allows for free flexion and extension of the knee.

Mechanisms of Traumatic Injury

Injuries to the ligamentous apparatus associated with the femoral condyles have characteristic biomechanical patterns.

ACL tears are most commonly non-contact in nature. This occurs during sudden deceleration or directional changes (cutting maneuvers) when the foot is rigidly fixed on the surface and the femur shifts by inertia. Internal rotation of the tibia at this moment critically increases fiber tension. Valgus or varus loads can also lead to a tear, but this typically happens only after the collateral ligaments have failed.

PCL injuries require a higher energy mechanical impact. The classic scenario is a «dashboard injury» (dashboard injury) during a motor vehicle collision, where the flexed knee receives a strong direct blow from the front, displacing the tibia posteriorly relative to the femur. Less commonly, the cause is extreme hyperextension of the joint.

Clinical Presentation and Physical Tests

At the moment of the ACL tear, the patient often feels or hears a characteristic «pop», followed by rapidly increasing pain and swelling (hemarthrosis). It is important to remember that blood accumulated in the joint can create the illusion of stability during examination.

Specific manual tests are used for diagnosis:

1. Lachman test (Lachman test): the gold standard of physical examination. The examiner stabilizes the femur and pulls the tibia anteriorly with the knee flexed at 30 degrees. The absence of a «firm endpoint» indicates a tear. A false-negative result is possible in the presence of pronounced hamstring spasm or tense effusion.
2. Anterior drawer test: a less accurate counterpart assessing tibial translation with the knee flexed at 90 degrees.
3. Pivot shift test (Pivot shift test): detects tibial subluxation with internal rotation and subsequent reduction with a clunk upon knee flexion.

Unlike PCL injuries, ACL injuries are usually not accompanied by an audible click. The main symptoms are diffuse pain and limping. The primary diagnostic maneuver is the posterior drawer test, which reveals excessive posterior translation of the tibia.

Instrumental diagnostics and treatment

Examination always begins with radiography to rule out bone pathology (including condylar fractures). A specific radiographic sign of an ACL injury is the Segond fracture. The "gold standard" for visualizing the ligaments themselves is MRI. On sagittal slices, an ACL tear often reveals "kissing contusions" (kissing contusions)—bone marrow edema zones on the lateral tibial plateau and femoral condyle resulting from their impact.

Principles of treatment:

• Conservative management: indicated for mild injuries or in patients with low activity demands. The mainstay is physical therapy and bracing. Chronic ACL insufficiency leads to instability ("giving way"), whereas PCL insufficiency causes anterior knee pain due to quadriceps overload.
• Surgical management: reconstruction is indicated for young and active patients. The ruptured ligament is excised, and a graft (auto- or allograft) is placed into newly formed bone tunnels in the femur and tibia. In patients under 25, using autologous tissue (e.g., hamstring tendons) is preferred to reduce the risk of re-rupture.

Any surgical intervention requires prolonged postoperative rehabilitation with gradual restoration of range of motion and strengthening of the muscular support system.

Class and exam questions

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Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.