Overview
The growth plate, or physis, is a region of specialized cartilage located near the ends of long bones. It is crucial for bone growth in both length and width. On X-rays, the physis appears as a dark line because cartilage is not calcified. As a child matures and growth slows, the physis gradually transforms into solid bone. Boys typically stop growing around 16 years of age, and girls around 14, though this can vary.
Fractures involving the physis are common because the cartilage is weaker than the surrounding bone and even the ligaments that connect bones in a joint. Despite this, physeal fractures heal rapidly due to the high activity of the growth plate. Prompt treatment by an orthopedic specialist within 5 to 7 days is important, as the bone may begin to heal quickly, making realignment more challenging if needed.
Physeal fractures account for 15-30% of all pediatric fractures, often occurring in the fingers, wrist, or lower leg. These can result from acute trauma or stress fractures due to repetitive use, such as in gymnasts or pitchers.
Anatomy
Types
Physeal fractures are classified using the Salter-Harris system:
- Type I Fractures: These occur entirely through the physis. They may be a simple crack or a complete disruption with bone separation.
- Type II Fractures: These fractures extend partially through the physis and then out into the shaft of the bone away from the joint.
- Type III Fractures: These go partially through the physis and exit into the joint, potentially disrupting the joint surface.
- Type IV Fractures: These extend through the shaft of the bone, the physis, and out the end of the bone at the joint.
- Type V Fractures: These involve crushing injuries to the physis and can be challenging to detect on X-rays.
Symptoms
Signs of a physeal fracture include a deformed limb, swelling, pain, limited movement, and bruising. Persistent pain, even without obvious deformity, may also indicate a fracture.
Diagnosis & Treatment
Examination
The doctor will assess the injury site for swelling, bruising, and pain, and may gently move the joints. Checking nerve function and circulation in the affected limb is also essential.
X-Rays and Tests
Typically, X-rays are sufficient for diagnosing physeal fractures. In some cases, an MRI or CT scan may be required for a more detailed view.
Non- Operative Treatment
Treatment varies based on the bone involved, the child’s age, and the fracture pattern. Physeal stress fractures generally heal with rest. A splint or cast may help manage pain, and it's important to reduce or modify activities that contributed to the stress fracture, such as limiting pitch counts for pitchers or reducing gym time for gymnasts.
Operative Treatment
For fractures involving the joint, surgery is often necessary to ensure proper alignment of the joint surface and growth plate. Surgery may be required in the following situations:
- There is a laceration near the fracture.
- The fracture cannot be properly aligned with a cast.
- The bones have started healing incorrectly and cannot be adjusted.
- The fracture is near the elbow with significant misalignment.
Surgical options may involve temporary pins, plates, or screws to stabilize the bones. Post-surgery, a cast or splint may still be used to aid in healing.
Outcomes
Growth plate fractures, especially those in the femur, require monitoring for 9 to 12 months to ensure proper bone growth. Repeat X-rays are necessary to check for normal growth. In rare cases, if a bony bridge forms across the physis, growth may stop or become irregular. If this occurs, your doctor may recommend surgery to prevent or correct deformities, which could involve removing the bony bridge, realigning the bone, or, in very rare cases, lengthening the bone.