Interventions for treating growth plate fractures of the distal femur: a systematic review protocol
Authors: Hayes Nicholas , Umapathysivam Kandiah , Foster Bruce 
Published: December 2014

Review question/objective
1. What are safe and effective interventions for the management of distal femoral growth plate fractures in children in terms of rates of growth deformity and rates of growth arrest?
More specifically, the objectives are to compare:
1 different methods of surgical treatments in the acute management of distal femoral growth plate fractures in children and adolescents;
2 different methods of non-surgical treatments in the acute management of distal femoral growth plate fractures in children and adolescents;
3 surgical versus non-surgical treatments in the acute management of distal femoral growth plate fractures in children and adolescents; and
4 different outpatient follow-up strategies, in particular, frequency of visits, frequency of radiographic evaluation and longevity of patient follow-up, following treatment of distal femoral growth plate fractures in children.
Surgery will be defined as treatment either by incision or physical manipulation by a surgical doctor.

Background

Description of the condition

The growth plate, or physis, is located between the epiphysis and metaphysis at the end of long-bones in children and young adults. It is the region of the bone where tightly-regulated endochondral ossification is responsible for longitudinal growth.1,2 The distal femoral physis is anatomically significant in that it contributes 70% of the longitudinal growth of the femur, equating to approximately 40% of the length of the lower extremity.3-6 Previous studies analyzing growth plate fractures found that physeal fractures account for approximately 15-30% of pediatric fractures and up to 4% of total pediatric fractures involve the distal femoral physis.7,8 At the distal femoral physis, major anatomical structures are the lateral notch, anteromedial notch, central ridge, lateral ridge, and medial peak.9 During childhood bony development, the central ridge has the most pronounced decrease in height and surface area, whilst the lateral notches deepen.9

From birth, there are three distinct periods of growth velocity.10 They are from birth to five years of age, from five years of age to puberty, and from puberty onwards. The most accelerated phase of childhood growth occurs at puberty.10,11 As skeletal maturity approaches, the central ridge has the highest relative decrease in size. This change in morphology accounts for a decrease in mechanical stability and therefore predisposes the physis to injury.9 With growth, the epiphysis becomes less cartilaginous.12 Riseborough et al. observed distal femoral physeal injuries in children, noting a greater distribution of higher energy injuries in the younger of these, hypothesizing a thicker periostium protects the physis from the lesser forces.13

The physis of the distal femur is inherently weaker than the ligaments of the knee. Thus, if an injuring force is applied to this area, a physeal fracture will more readily be produced rather than a disruption to these ligaments.14,15 A fracture to the distal femoral epiphyseal plate injury is frequently the result of a high energy injury. Common mechanisms of injury include motor vehicle accidents (including pedestrians and cyclists), sports-related injuries, and falls.16-18 Historically, when wagons and carts were common transportation vehicles, a child's foot lodging in a spoke would readily result in a distal femoral physeal fracture causing significant morbidity and mortality.19 Abduction, adduction, hyperflexion and hyperextension are known mechanisms of distal femoral physeal fractures.5

A distal femoral physeal injury is fraught with numerous potential complications.3,5,17,20,21 Complete or partial growth arrest is commonly seen, which may manifest clinically in leg length discrepancy and angulation deformity.5 Additionally, limitation on knee motion, quadriceps atrophy, osteomyelitis or osteoarthritis may result from this injury.5,22,23 A meta-analysis by Baesner studying distal femoral physeal fractures reported an incidence of 52% in growth disturbance with 22% of the growth disturbance greater than 1.5cm.21 Arkader et al. reported a complication rate of 40% with growth arrest the most common.20

It has been suggested that growth disruption and angular deformity follows peripheral bridging as a result of disruption to the zone of Ranvier.5,15 A radiological study proposed a graduation of the physeal injury, which may begin as an incomplete bridge at the central area with dense, sclerotic core causing continued disruption remaining.24

It has been postulated that fracture type, fracture mechanism, direction of injury, displacement, nature of physis, and the treatment mode may correlate with the clinical outcome of a distal femoral physeal injury.11,17,21,25,26 Some authors have suggested follow up until skeletal maturity as potential for late complications may exist.3,17,26

For epiphyseal fractures of the distal femur, modes of diagnosis of and further evaluation include plain radiography and computed tomography. Magnetic resonance imaging is able to give gradient sequences to highlight the physis and is the most suitable method for detecting bone-bridge formation.27,28

Numerous classification systems for physeal fractures have been proposed and developed since Foucher's grading in 1863. More contemporarily, in perusing the literature, the Salter Harris (SH) Classification, described in 1963, is most commonly used.17,21,29 It was developed to correlate mechanism of injury to the appearance of the fracture lines, repair and growth prognosis.30,31 Additions and further suggestions to the SH Classification have been made in recent years.15,32-35

A SH I fracture is considered to involve the cartilage of the growth plate. SH II involves bony disruption from the metaphysis to the growth plate. A SH III fracture is from the epiphysis to the growth plate. The SH IV injury is through the metaphysis, physis and epiphysis, whereas a SH V fracture is a crush injury to the physis.
For growth plate fractures, the aim of management is to keep the metaphysis, epiphysis and physis separate so that the physeal cartilage is able to grow in between to separate them.36 Management decisions regarding these injuries are generally constructed around the degree of displacement and SH grading.17,20,21,23,29

In a search of available literature, there was no systematic literature review evaluating the most effective treatment methods for distal femoral physeal fractures. Published studies show a degree of inconsistency in treatment methods for similar fractures and presentations.
Generally however, for distal femoral physeal fractures, non-displaced SH I fractures are managed conservatively in a full length leg cast or hip spica. If displacement does exist, closed manipulation with a cast may be used. Internal fixation involving K wires or pinning through the epiphysis offers another option for this fracture type. Non-displaced SH II fractures may be managed non-operatively but must be monitored closely for loss of reduction. Displaced SH II as well as well as SH III and IV have been managed operatively, although exact methods of surgical approach and devices vary.17,20,21,23,29

Whilst in some cases, surgery has shown less risk of re-displacement of the facture, this is a treatment not without risks.26 Potential surgical complications include osteomyelitis, injury of surrounding structures including vascular injury, nerve injury and growth plate injury.5,16,26

The decision regarding the exact management of these fractures is made by the treating specialist. It may be influenced by factors such as knowledge-base, experience, comfort level of the surgeon and available resources.
The purpose of this review is to synthesize the best available evidence regarding the effectiveness of these interventions.