How I Manage Physeal Fractures About the Knee
Carl Stanitski, MD, with Carl ShermanTHE PHYSICIAN AND SPORTSMEDICINE - VOL 25 - NO. 4 - APRIL 97
In Brief: Knee injuries in children and adolescents often involve the growth plate (physis), as well as the adjacent bony areas of the femur, tibia, or patella. Young patients who have injured knees require careful clinical and radiographic assessment to determine the extent of their injuries, with specific management to minimize the potential for growth arrest and resultant deformity. This article discusses distal femoral physeal, proximal tibial physeal, tibial eminence, patellar sleeve, and tibial tubercle fractures in skeletally immature patients.
The knee, a complex, vulnerable joint, is a common site of sports injury in children and adolescents (figure 1) (1). The immature skeletal system is susceptible to a spectrum of injuries distinct from those in adults. When the growth plates (physes) are damaged, there is a risk of growth arrest and subsequent development of deformity, particularly for preadolescent patients who have significant years of growth remaining.
While management of many childhood knee injuries is beyond the scope of the primary care physician, he or she plays an essential role in initial evaluation and referral.
Why are the physes vulnerable to injury?
What role should primary care physicians take in treating physeal fractures?
Standard-view initial radiographs—anteroposterior (AP), lateral, skyline, and tunnel views —should be obtained. I would not encourage primary care physicians to order a more detailed imaging evaluation, such as magnetic resonance imaging (MRI) or computed tomography (CT). These studies are best ordered, if needed, by the person involved with the ultimate specific care of the injury, so clinical correlation can be done with the imaging study. Prolonged, nonspecific immobilization is to be avoided. As with any injury, a specific diagnosis is required so specific treatment can be initiated, and misuse, disuse, and abuse of the injured area can be prevented.
Distal femoral physeal fractures are a common type of physeal injury. Why?
Distal femoral physeal fractures are about 10 times as common as proximal tibial fractures. They can occur at any age, but are most often seen in boys aged 10 to 14. This age range is a time of significant growth, when the physis is weakest.
The usual cause of these fractures is a direct blow to the sides or front of the knee in a sports or vehicular accident. In sports, the injury classically happens to a young athlete who has one foot planted and is starting to make a turn when someone falls on the outer aspect of the knee of the fixed leg, producing a significant valgus load.
What are the clinical features of distal femoral physeal fractures?
In doing the standard knee physical exam, first assess the uninjured knee for evidence of ligamentous laxity in the anterior-posterior, medial-lateral, and rotational directions. Inherent laxity varies from one individual to another, and one doesn't want to interpret a normal condition as pathological. Then, with the injured knee in extension and at 30° of flexion, see if the application of gentle valgus and varus stress increases pain. I emphasize gentle—this should not be a vigorous maneuver. Assess anterior-posterior stability with the Lachman and drawer tests (anterior and posterior).
Look for effusion in the knee joint. Check for focal tenderness about the knee, at the lateral and medial metaphyseal flare of the femur at the level of the physis as opposed to the joint line below it. In addition, check for focal tenderness at the medial or lateral metaphyseal flare of the tibia.
Check circulation and sensation of the foot to detect possible vascular or neurologic compromise. Damage to the peroneal nerve may occur, particularly with a varus injury mechanism.
Comparison AP and lateral views of the opposite knee may help assess loss of physeal symmetry. Figure 2 shows an abnormal widening of the physis. Follow-up radiographs at 10 days to 2 weeks may also show a periosteal reaction subsequent to fracture healing.
Some people advocate radiographic stress views to demonstrate fracture instability when attempting to rule out a physeal fracture. I feel that this strategy only adds injury to injury. If the fracture is, in fact, displaced, the radiograph will show it. Any new information provided by stressing the knee won't affect management, and the stress maneuver may cause further physeal and epiphyseal damage. If the physis is tender, then an undisplaced fracture can be assumed to have occurred even if the initial x-rays are "normal."
How do you manage distal femoral physeal fractures?
Type II fractures involve the metaphysis as well as the physis. If patients have type I or type II fractures with displacement, reduction is required. This can usually be done closed, by manipulation. A displaced type II fracture usually needs internal fixation to provide stability after reduction.
Type III fractures involve the physis, epiphysis, and joint; and type IV fractures involve the physis, epiphysis, metaphysis and joint. If displaced, these injuries require open reduction and internal fixation to restore physeal and joint congruity.
What is the outlook for patients who have had distal femoral physeal fractures?
If areas are involved asymmetrically, as in type II, type III, and type IV fractures, the damaged portion of the physis may be "spot welded" and stop growing, producing a spectrum of deformities. A peripheral closure causes angular deformity in which one side grows and the other does not. Central physeal arrests tend to cause leg length inequality. Remember that the distal femoral physis contributes two thirds of the adult length of the femur, and just over one third of the length of the lower extremity.
The long-term effects of distal femoral physeal fractures depend in part on the age of the patient at the time of the injury. In a patient who is close to skeletal maturity, the concern is not as great as it would be for someone younger. In a younger patient who has significant growth remaining, the potential for deformity is high if asymmetrical physeal closure occurs.
The take-home message: Patients who have had distal femoral physeal fractures require long-term evaluation after the acute phase to watch for subsequent asymmetrical growth. Future leg length equalization and deformity corrective procedures may be necessary.
When do you suspect a proximal tibial physeal fracture?
The patient typically complains of pain. I look for point tenderness at the physis and joint line. I also assess knee stability, as well as motor, circulatory, and sensory function distal to the injury. This type of fracture will usually be revealed by AP and lateral radiographs of the knee (figure 4). Comparison radiographic views of the uninjured knee often resolve doubts in cases of an undisplaced fracture.
How do you manage proximal tibial physeal fractures?
These patients do well overall. There seems to be less potential for growth arrest and subsequent deformity than with fractures of the distal femoral epiphysis.
What complications do you look for in patients who have proximal tibial physeal fractures?
After reduction of the fracture, it is advisable to admit the child to the hospital and observe him or her for indications of progressive neurologic or vascular damage, as well as for loss of pulses and sensory changes distal to the injury. Slowly increasing leg pain, especially with motor paralysis, often indicates the development of a compartment syndrome.
How do you identify tibial eminence fractures?
The patient will typically have knee pain, with significant effusion, and will refuse to move the knee. If he or she is cooperative enough for a clinical knee examination, it may show evidence of increased anterior translation: The tibia can be pulled forward more on the injured side than on the other side, because the tibia has lost the check rein effect of the ACL.
It is important to be alert for damage to other knee structures. Tenderness, especially at the joint line, suggests mid- to posterior meniscal injury.
What will radiography show about tibial eminence fractures?
A tunnel view of the knee (figure 6) may be helpful to supplement, but not replace, the lateral one. This specialized view outlines the femoral notch and tibial eminence.
How do you manage tibial eminence fractures?
A slightly or completely displaced (type II or type III) fracture can usually be reduced under arthroscopic control. Fixation is required for the displaced fragments once they are reduced.
These patients generally do well if the fracture has been reduced appropriately, and other injuries—to the meniscus, for example—are managed properly. There is often mild anterior translation on follow-up examination, but this does not result in functional instability.
How do patellar sleeve fractures occur?
The typical patient is a preteen who fell on a flexed knee. He or she is unable to move the knee, and pain is localized at the site of injury. The physician can sometimes palpate a gap between fracture fragments. The patella rides high (proximally), compared with the uninjured side.
Why are patellar sleeve fractures frequently missed?
With a high index of suspicion, the diagnosis can be made on clinical grounds. When I find focal tenderness at the junction of the distal patella and proximal patellar tendon, a gap, and an inability to extend the knee, I think of a sleeve fracture.
How do you manage patellar sleeve fractures?
The outlook for the patient with a patellar sleeve fracture is generally good if the diagnosis is made promptly.
Why are tibial tubercle avulsion fractures different from other types of physeal fractures?
What is the clinical presentation in patients who have tibial tubercle avulsion fractures?
The physical exam shows focal tenderness at the site of the injury, often with significant ecchymosis and swelling. In displaced fractures, the patella rides high (proximally) compared with the other side. The patient will be unable to bear weight on the leg or extend the knee because of pain and disruption of the quadriceps mechanism.
How do you manage tibial tubercle avulsion fractures?
Patients who have had tibial tubercle avulsion fractures usually do well. There's no real danger of physeal arrest since skeletal growth is, in almost all cases, complete.
Dr Stanitski is the chief of orthopedic surgery at Children's Hospital of Michigan and a professor of orthopedics at Wayne State University School of Medicine, both in Detroit. He is also an editorial board member of The Physician and Sportsmedicine. Mr Sherman is a New York City freelance writer. Address correspondence to Carl Stanitski, MD, Children's Hospital of Michigan, Department of Orthopedic Surgery, 3901 Beaubien Blvd, Detroit, MI 48201.
Copyright (C) 1997. The McGraw-Hill Companies. All Rights Reserved