| disease | Femoral Condyle Fracture |
Fractures of the hip bone account for 0.4% of all body fractures, but the treatment outcomes are often unsatisfactory. The area around the femoral condyle is attached with joint capsules, ligaments, muscles, and tendons. The fracture fragments are pulled by these tissues, making reduction difficult and hard to maintain. Fractures of the hip bone can complicate the popliteal artery, nerves, and extensive injury to surrounding soft tissues. When accompanied by injury to adjacent supporting structures such as collateral ligaments and cruciate ligaments, it can lead to knee joint instability. Injury to the quadriceps and suprapatellar bursa can also cause adhesions in the knee extension apparatus, impairing knee joint function. Fractures can disrupt the corresponding joints between the femoral condyle and tibial plateau, and between the patella and femoral articular surface, altering the normal anatomical and mechanical axes of the knee, and disrupting the normal load and transmission of the knee joint. Fractures of the hip bone are prone to fragment separation without collapse, and are likely to result in "T" or "Y" type fractures.
bubble_chart Pathogenesis
The hip bone is prone to separation of bone fragments without collapse during a fracture. This is because the triangular patella acts like a wedge pointing towards the anatomical weak point of the femoral condyle, the intercondylar fossa, which easily splits the two condyles. Additionally, the femoral shaft has a forward curvature, with the anterior cortex being strong and the posterior cortex reinforced by the linea aspera. Therefore, fractures are likely to occur near the femoral condyle, where the cortical bone transitions to the weaker cancellous bone.
When the muscles around the tibiofemoral joint contract, the femoral condyle is subjected to stress from both the femoral condyle and the patella. As the knee joint moves from extension to flexion, the stress between the patellofemoral and tibiofemoral joint surfaces increases to varying degrees. The resultant force of these two stresses points towards the posterior superior aspect of the femoral condyle between the patella and the femur. Whether in extension or flexion, some part of the joint surfaces always remains in contact. During knee flexion, the patella also moves from front to back, which aligns with the knee joint often being in a flexed position during injury. This facilitates the wedge effect of the patella under external force, making the femoral condyle prone to "T" or "Y" type fractures.Mechanism and types of injury: (1) Direct force: Often seen in high-speed impacts, where the force is transmitted through the patella, turning the stress into a wedge force that causes a single or double hip bone fracture. When the force acts horizontally on the supracondylar region, it often results in a supracondylar fracture.
(2) Indirect force: Falling from a height, with the knee joint in either extension or flexion, can cause fractures in different parts of the lower femur due to varying stress directions.
The knee joint often has a physiological valgus, with more concentrated stress on the lateral condyle, which is structurally weaker than the medial side. Therefore, injuries often occur on the lateral condyle. Valgus stress can cause an oblique fracture of the lateral femoral condyle, sometimes resulting in an avulsion fracture of the medial epicondyle, a tear of the medial collateral ligament, or a fracture of the lateral tibial plateau. Varus stress can cause an oblique fracture of the medial femoral condyle. If a tibial plateau fracture occurs, due to the stronger resistance of the medial tibial plateau, the fracture line first appears on the lateral side of the tibial spine, passing through the weak area between the shaft and the metaphysis before turning to the medial side. Based on the location and type of fracture, there are several types:
bubble_chart Clinical Manifestations
There is a clear history of trauma. Hemarthrosis, swelling, localized pain, and dysfunction of the knee joint. Various deformities may occur. Abnormal movement is present. Often accompanied by meniscus or ligament injury. Attention should be paid to associated vascular and nerve injuries. X-ray imaging helps in confirming the diagnosis and classification.
bubble_chart Treatment Measures
For femoral hip bone fractures without displacement or grade I displacement, aspirate the intra-articular hematoma and apply compression bandaging. Use traction or a gypsum cast for immobilization, and begin knee joint movement after 4-6 weeks.
With the continuous improvement of internal fixation devices, even more complex femoral hip bone fractures can achieve relatively reliable internal fixation. Therefore, the current trend in treatment leans towards surgical intervention.
Surgical indications, in addition to those shared with general intra-articular and periarticular fractures, include the following specific conditions in this area.
These include combined ligament or meniscus injury, severe vascular or nerve injury, and free fracture fragments with poor blood supply.
Methods of internal fixation are as follows:
(1) Angled plate: The plate is at a 95° angle, ensuring stability at the fracture site.
(2) Plate and screws: This includes screws specifically designed for femoral hip bone fractures and ordinary plates that are manually bent to fit the femoral condyle. These are characterized by strong adaptability and ease of use. However, they are prone to loosening or even breaking at the junction of the plate and screws, making it difficult to ensure stability at the fracture site. They often need to be used in conjunction with gypsum external fixation. To overcome these drawbacks, new types of plate screws have been designed. Additionally, there is the "AO" T-shaped plate, which is wider at the distal end and has multiple screw holes, allowing screws to be inserted from the front or back into the bone holes to fix the femoral condyle.
(4) Internal fixation pins: Steinmann pins can be used in cases where the bone fragments are not severely comminuted. Eiffel Tower pins can be used for femoral hip bone fractures combined with supracondylar fractures.
