Femoral condyle fractures

　　Femoral condyle fractures are prone to fragment separation without collapse, which is due to the triangular patella, like a wedge, pointing to the anatomical weakness of the intercondylar fossa of the femoral condyle, which is easy to split the two condyles. In addition, the femoral shaft has a forward-bending arc, with the anterior bone cortex being strong and the posterior bone cortex being reinforced by the femoral rough line. Therefore, fractures are prone to occur near the femoral condyle, with the cortical bone transition becoming a weak part of cancellous bone.

　　When the muscles around the patellofemoral joint contract, the femoral condyle bears the stress from both sides of the femoral condyle and patella. As the knee joint extends to flex, the stress between the patellofemoral joint and the tibiofemoral joint surface increases to varying degrees. The resultant force direction of these two stresses points to the posterior superior part of the patella and the femoral condyle. Whether in the straight or flexed position, there is always a part of the joint surface in contact. When the knee is flexed, the patella also has a movement from front to back, consistent with the knee often being in a flexed state during injury. Under the action of external force, this is conducive to the wedge-shaped action of the patella, and therefore, it is easy for the femoral condyle to produce 'T' or 'Y' type fractures.

　　Mechanism of injury and types:

　　1. Direct external force:It is more common in high-speed collisions, where the external force changes the stress into a wedge force that causes single or double condyle fractures through the patella. When the external force acts horizontally on the supracondylar region, it often causes supracondylar fractures.

　　2. Indirect external force:Falling from a height, in the extended or flexed position of the knee, different directions of stress can cause fractures at different parts of the lower end of the femur.

　　The knee often has physiological varus, and the stress on the outer condyle is more concentrated than on the medial side, and the structure of the outer condyle is weaker than that of the medial side. Therefore, injuries often occur at the outer condyle. The varus stress can cause oblique fractures of the femoral outer condyle, and sometimes produce avulsion fractures of the superior medial condyle, tears of the medial collateral ligament, or lateral tibial plateau fractures. The varus stress can cause oblique fractures of the femoral medial condyle. If a tibial plateau fracture occurs, due to the strong resistance of the medial condyle of the tibial plateau, the fracture line first appears on the lateral side of the tibial spine, passes through the vulnerable area between the shaft and the metaphysis, and then turns to the medial side. According to the fracture site and type, there are the following types: ① Single condyle fractures - anterior, posterior, oblique, and intermediate types; ② Intercondylar fractures - 'V' type, 'T' type, 'Y' type; ③ Supracondylar fractures - spiral, oblique, transverse; ④ Epiphysial separation; ⑤ Cartilage and osteochondral fractures.

　　Femoral condyle fractures often occur with meniscus or ligament injuries, and attention should also be paid to complications such as vascular and nerve injuries. Some patients may also develop compartment syndrome:

　　Compartment syndrome is a serious complication after fractures, and there are few reports of compartment syndrome occurring after the fracture of the upper femoral condyle. Fractures of the upper femoral condyle are mostly caused by high-speed injuries and high-altitude falls and are divided into flexion and extension types. The distal end of the flexion-type fracture moves posteriorly due to the traction of the quadriceps femoris, gastrocnemius, and the contraction of the joint capsule. The strong contraction of the thigh muscles can cause the fracture to shorten, which is easy to compress or injure the popliteal artery, veins, and nerves. The compressed popliteal artery and veins have reduced blood flow, which aggravates the ischemia, edema, and increased tissue pressure in the lower leg. When the tissue pressure exceeds the arterial pressure, muscles produce substances such as histamine due to ischemia, which increases capillary permeability, causing a large amount of plasma and fluid to渗入 tissue spaces, aggravating edema. The tissue pressure in the compartment further increases, forming an ischemia-edema vicious cycle, which eventually leads to muscle necrosis and nerve paralysis.

　　Fractures of the femoral condyle are commonly seen in emergency patients; the lower end of the femur is swollen, with an inner condyle and an outer condyle, surrounded by joint capsules, ligaments, muscles, and tendons attached around the condyles. There is a groove-shaped intercondylar fossa between the two condyles, which is relatively weak and prone to fractures at this location. Fractures of the femoral condyle can be accompanied by widespread injuries to the popliteal artery, nerves, and surrounding soft tissues. When there are injuries to adjacent supporting structures such as collateral ligaments and cruciate ligaments, knee instability can occur, and extensor knee adhesions can also be caused by injuries to the quadriceps femoris and suprapatellar bursa, impairing knee function. Fractures can cause damage to the corresponding joints between the femoral condyle and the tibial plateau, the patella and the femoral articular surface, changing the normal anatomical axis and mechanical axis of the knee, and destroying the normal load and conduction of the knee joint.

　　One, Local symptoms of fracture:Mainly marked swelling of the knee joint, tenderness at the intercondylar or medial and lateral condyle, and the conductive percussion tenderness is also more obvious.

　　Two, Knee joint dysfunction:Since it is an intra-articular fracture, slight movement can cause severe pain, so the degree of restriction of joint function is more obvious.

　　Three, Special examination:The signs of joint effusion (fluid) and floating patella test in the knee joint are mostly positive, and routine examination should be performed.

　　Four, Classification:According to the location and shape of the fracture, it is generally divided into the following four types:

　　1, Unicondylar fracture:Refers to unilateral fractures of the medial or lateral condyle, which can be divided into the following two types:

　　(1) Non-displaced type: refers to non-displaced fissure fractures, or fractures with longitudinal displacement not exceeding 3mm and rotation not exceeding 5°.

　　(2) Displaced type: refers to displacement exceeding the aforementioned standards.

　　2, Bicondylar fracture type:Refers to patients with simultaneous fractures of the medial and lateral condyles, whose shape is similar to a V or Y, and can also be called V-shaped fracture or Y-shaped fracture, generally accompanied by varying degrees of displacement.

　　3, Comminuted fracture type:Generally, in addition to intercondylar fractures of the femur, there are often fractures of the supracondylar or adjacent parts, among which those resembling the letter T are called T-shaped fractures, and the displacement of the fracture ends is often more obvious.

　　4, Complex fracture type:Refers to patellar fractures with vascular and nerve injuries, and all types of displaced fractures are possible.

　　Patellar fracture seriously affects the daily life of patients, so it should be actively prevented. Patellar fracture is a traumatic disease with no effective preventive measures. Paying attention to production and life safety and avoiding accidents is the key.

　　For patients with patellar fracture, the following examinations should be performed:

　　1, Check the foot, toe movement, dorsal foot sensation, and dorsal foot artery pulsation, and exclude the possibility of nerve and vascular injury.

　　2, If the patient's condition permits, the knee joint lateral ligament and cruciate ligament should be checked for injury at the same time.

　　3, X-ray examination, take anteroposterior and lateral views of the knee joint.

　　4, Blood routine, blood type, and coagulation time check, elderly patients should have an ECG and urine sugar test.

　　What is good for patellar fracture patients to eat?

　　1, Early stage:The principle of diet coordination is to focus on light and clear food, such as vegetables, eggs, dairy products, fruits, fish soup, lean meat, etc.

　　2, Middle stage:Bone soup, panax notoginseng chicken, animal liver.

　　3, Later stage:Old hen soup, pork bone soup, lamb bone soup, deer tendon soup, braised water fish, etc., those who can drink can choose Eucommia ulmoides and bone broken wine, chicken blood vine wine, tiger bone papaya wine, etc.

　　What should patellar fracture patients avoid eating?

　　Avoid sour and spicy, dry and hot, and greasy foods early on, especially not to take greasy and nourishing foods too soon, such as bone soup, fatty chicken, braised water fish, etc. In addition, fruit syrup and sugar are also not suitable.

　　Femoral condyle fractures are mostly caused by traumatic factors, with no special preventive measures. Paying attention to safety in production and life and avoiding trauma is the key.

　　1. Treatment

　　Due to the differences in fracture type, displacement degree, whether reduction is possible, and each physician's clinical experience, there are significant differences in treatment, but a more secure method should still be adopted.

　　(1) Satisfactory alignment

　　Including non-displaced fractures and those with displacement that have been reduced manually to the original position, basically achieving anatomical alignment, can be treated with non-surgical methods. The lower limb is fixed with a cast, but attention should be paid to avoid inversion and eversion as well as rotational displacement.

　　(2) Poor alignment

　　It is advisable to perform open reduction and internal fixation as soon as possible, and the specific method of internal fixation should be mastered according to the type of fracture. Common methods include:

　　① Tension screw fixation: Used for unicompartmental fractures.

　　② Simple bone dowel fixation: Suitable for unicompartmental fractures.

　　③ Bone dowel + plate screw fixation: Often used for T-shaped, Y-shaped, V-shaped, and comminuted fractures.

　　④ L-shaped (Moore type) plate: The scope of application is the same as before, but the fixation strength is not as good as the former, and tension screws can be added.

　　⑤ Other internal fixation: Depending on the type of fracture, displacement, surgical conditions, and personal habits, long screws,钢丝, and other internal fixation materials can be selected appropriately to restore the integrity of the joint surface and facilitate the recovery of lower limb function.

　　⑥ Combined with other injuries: Appropriate treatment should be given according to the situation.

　　Vascular injury: Often due to stimulation of the fracture end causing arterial spasm, rupture is less common. First, manual reduction under traction should be performed; if the dorsal artery of the foot recovers or improves, it can be continued to observe and scheduled for exploration surgery (which can be performed simultaneously with open reduction and internal fixation); if the dorsal artery of the foot does not improve after reduction and there is a suspicion of arterial injury, immediate surgery should be performed to explore.

　　Nerve injury: Observation is the main treatment, unless completely ruptured, it is generally left for later treatment.

　　Combined with knee ligament injury: It is generally recommended to treat early, especially for those with complete rupture of collateral ligaments and cruciate ligaments. For meniscus rupture, it is not advisable to excise too much, only the edges or anterior and posterior angles of the rupture should be excised.

　　2. Prognosis

　　Reduction satisfactory, fixation firm, generally good prognosis.