Distal Femoral Physeal Fractures - Types, Symptoms, Diagnosis, and Management

Introduction

Growth plates (physis) are at the ends of the long bones such as the femur, tibia, fibula, radius, ulna, etc., which are the areas of new bone growth that add length and width to the bones. The femur bone begins to develop around the seventh week of gestation (pregnancy). The physis of the distal femur grows at a faster pace compared to the other bones and contributes to the majority of the femur bone growth. Thus any disturbance to this growth pattern can cause significant disturbances or deformities in children. The growth plates harden to form solid bones around puberty, usually between 16 to 18 years in males and 14 to 16 years in females.

What Are Distal Femoral Physeal Fractures?

Physeal fractures are growth plate fractures that are mainly seen in children; distal femur growth plates contribute to the majority of the linear growth of the body. The physis or the growth plates are made of cartilage and are weaker than the bones and susceptible to injuries or fractures. It requires immediate attention and proper treatment to avoid further complications.

What Are the Types of Distal Femoral Fractures?

Distal femoral fractures are classified according to Salter and Harris as follows:

• Type I - A complete separation of epiphysis from metaphysis without any bone fracture, but the widening of the growth plate occurs, along with other irregularities.

• Type II - The line of separation extends along the epiphyseal plate through a portion of the metaphysis. An oblique fracture pattern is seen in this type.

• Type III - The fracture extends from the joint surface to the weak zone of the epiphyseal plate and then along the plate to the periphery. It is usually seen in sports injuries and may be associated with cruciate ligament injuries.

• Type IV - This fracture is usually uncommon and extends from the joint surface through the epiphysis across the epiphyseal plate through the metaphysis. It extends vertically through the metaphysis and exits through the articular surface of the epiphysis.

• Type V - Crushing force applied through the epiphysis to one area of the epiphyseal plate, leading to fracture; it is usually rare and associated with severe knee injuries.

What Are the Causes of Distal Femoral Physeal Fractures?

Some of the causes of distal femoral fractures include; significant trauma caused due to falls in children and high-energy trauma such as vehicle accidents or sports injuries is mainly seen in adolescents.

What Are the Signs and Symptoms of Distal Femoral Fractures?

Some of the signs and symptoms of distal femoral fractures include

• Severe pain in the knee.

• Inability to bend the knee.

• Unable to bear weight.

• Swelling and tenderness of the knee.

• Abrasions and lacerations of the soft tissues in case of injuries.

• A significant deformity of the knee.

How Are Distal Femoral Fractures Diagnosed?

The doctor takes a complete medical history, followed by a physical examination. Patients usually present with swelling in the knee, associated with severe pain, and are unable to walk or bear weight on the legs. The presence of bruises, lacerations, and abrasions and the extent of the injury is noted. Tightness of the thigh muscles may be present, associated with sharp pain, leading to a knee held in a stretched position, called a Hamstring spasm. The thigh may appear short and angulated compared to the unaffected side. Skin is also evaluated for the presence of tenting to rule out open fractures. Perfusion and distal pulses are assessed to rule out injury to the blood vessels. Radiological investigations include

• X-Rays: Anteroposterior and lateral view radiographs of the knee, femur, and hip joint are preferred to determine the type of fracture and its extent.

• Computed Tomography (CT Scan): In some complex cases, it is advised to confirm the extension of the fractures into the joints and to aid in pre-operative planning in cases of surgical management.

• Magnetic Resonance Imaging (MRI): It is advised in cases of sports injuries and also to rule out other ligament injuries or soft tissue involvement.

Vascular injuries or injury to the blood vessels may be seen in some rare cases; a femoral arteriogram is required, or a neurovascular examination is performed.

• Femoral Arteriogram: A thin-walled 18 gauge needle is inserted proximal or distal to the site of injury, a single injection of 30 percent Meglumine of about 25 to 30 mL (milliliter) is given, and a radiograph is taken. It may show diminished pulses in case of vascular involvement. In case of nerve involvement, it leads to the injury of the peroneal nerve or the posterior tibial nerve, resulting in numbness or loss of sensation.

How Are Distal Femoral Fractures Managed?

The treatment of distal femoral physeal fractures mainly depends on the type of fracture, the presence or absence of displacement, and associated injuries.

• In cases of stable and undisplaced fractures, conservative management is indicated, wherein immobilization is done by a long-boot cast. It is applied from the groin up to the base of the toes and is essential to support the hip in flexion at an angle of 45 to 60 degrees and flexion of the knee at an angle of 60 degrees to prevent the moving of the cast. It is applied for around two to three weeks, with a weekly follow-up by radiographs.

• Displaced fractures are managed by open or closed surgical reduction, with stabilization. techniques using implants. The Salter-Harris type I fractures are managed by reduction using gentle manipulation to avoid damage to the growth plates. It is done using K- wires (Kirschner wires) which support the cast and provide additional protection. The size of the wire usually depends on the age of the individual. 1.6 mm (millimeter) K- wires are used in patients less than six years and 2 mm K-wires in case of patients older than five to six years. It is applied for around three to four weeks and then removed to prevent the closure of growth plates. Type III and IV fractures require anatomical reduction due to the involvement of joint surfaces. A rehabilitation program with strict avoidance of weight bearing is advised for five to six weeks.

What Are the Complications of Distal Femoral Fractures?

• Closure of the growth plates may occur, leading to growth arrest.

• Inflammation of the joints.

• Compartment syndrome may occur following soft tissue injuries and is characterized by increased muscle pain due to bleeding or swelling.

• Severe fractures may damage the blood vessels and nerves, especially the popliteal artery and peroneal nerve.

• The difference in the length of the affected leg may occur sometimes following the treatment, called the leg length discrepancy.

• Angular deformity of the leg may occur due to improper union of the fractures.

Conclusion

Distal femoral physeal fractures are seen in children and adolescents, usually occurring due to a trauma or a fall, or sports injuries leading to the fracture of the distal femur growth plates. It is associated with severe pain and swelling, difficulty walking, or inability to bear weight. Stable and undisplaced fractures are managed conservatively, but severely displaced fractures require open reduction and fixation. It requires immediate care and treatment as the closure of the physis may lead to further complications.