Vol 10, No 5, September/October 2002 345 The knee is a common site of in- jury in children and adolescents, especially those who engage in competitive sports. The physician who evaluates and treats fractures in the pediatric age group must be familiar with the types of injuries and complications that are unique to these patients. Fractures of the immature knee, such as those that involve the distal femoral and proximal tibial epiphyses, tibial tubercle apophysis, tibial spine, patella, articular cartilage, and proximal tibial metaphysis, are particularly challenging in terms of establishing the diagnosis and predicting long-term sequelae. An understanding of the classifica- tion, clinical and radiographic evaluation, treatment, and poten- tial complications of each type of injury can lead to more effective treatment as well as to clear com- munication with the child’s par- ents. Distal Femoral Epiphyseal Fractures Classification The most commonly used system to classify fractures involving the distal femoral epiphysis is that of Salter and Harris 1 (Fig. 1). In type I fractures, there is a separation through the physis with no involve- ment of the adjacent metaphysis or epiphysis. Type II fractures are the most common. In these injuries, the fracture line traverses the physis before exiting obliquely across one corner of the metaphysis. Displace- ment is usually toward the side of the metaphyseal fragment. A type III injury consists of a fracture through the physis that exits through the epiphysis into the joint. A type IV fracture consists of a vertical, intra- articular fracture that traverses the metaphysis, physis, and epiphysis. Most type III and IV injuries require accurate reduction, usually supple- mented by internal fixation, to align the physis and achieve a congruous joint surface. Type V fractures are crush injuries to the physeal cartilage. These rare injuries are usually diag- nosed in retrospect or by association with the mechanism of injury. Signs and Symptoms The patient with a distal femoral epiphyseal fracture usually presents with effusion of the knee joint, local soft-tissue swelling, and tenderness over the physis. In displaced injuries, deformity may be evident, and soft or muffled crepitus with motion often can be felt. In the anteriorly displaced, or hyperextension, injury, the patella becomes prominent and the anterior skin is often dimpled. With posterior displacement of the epiphysis, the distal metaphyseal fragment becomes prominent just above the patella. Although arterial injury is less common than with a proximal tibial physeal injury, a care- ful neurovascular examination is Dr. Zionts is Professor, Department of Orthopaedics and Pediatrics, Keck School of Medicine, University of Southern California, and Director, Pediatric Orthopaedics, Women’s and Children’s Hospital, University of Southern California Medical Center, Los Angeles, CA. Reprint requests: Dr. Zionts, Room 3L-31, 1240 North Mission Road, Los Angeles, CA 90033. Copyright 2002 by the American Academy of Orthopaedic Surgeons. Abstract Traumatic forces applied to the immature knee result in fracture patterns differ- ent from those in adults. The relative abundance of cartilage in the knee of the growing child may make the diagnosis of certain injuries more challenging. If plain radiographs fail to reveal a fracture, a stress radiograph, computed tomog- raphy scan, or magnetic resonance imaging study may help to establish the diagnosis. Certain fractures, such as hyperextension injuries to the distal femoral or proximal tibial epiphysis, or displaced tibial tuberosity fractures, may be especially susceptible to neurovascular problems. Although the use of appro- priate treatment techniques may minimize the occurrence of late complications such as malunion and physeal bridging, not all problems are preventable. A careful discussion of the injury with both patient and parents should stress the importance of follow-up so that any problems that do occur can be promptly addressed. J Am Acad Orthop Surg 2002;10:345-355 Fractures Around the Knee in Children Lewis E. Zionts, MD warranted to rule out damage to the popliteal vessels or peroneal nerve. Imaging Studies Anteroposterior and lateral radio- graphs should routinely be obtained to evaluate the displacement of the fractures. Oblique radiographs may help reveal minimally displaced fractures. Gentle-stress radiographs can help differentiate a physeal sep- aration from a ligamentous injury in a patient who has pain and appar- ent laxity of the knee and whose plain radiographs fail to reveal a fracture. Adequate analgesia can alleviate muscle spasm and protect the physis from further damage during the examination. Magnetic resonance imaging (MRI) or computed tomography (CT) also may help to identify frac- ture lines in nondisplaced injuries. 2,3 Naranja et al 3 found MRI useful for diagnosing fractures when an injury was not apparent on plain radio- graphs, especially in children with a preceding traumatic event, effusion or swelling, and refusal to bear weight on the extremity (Fig. 2). Treatment The goals of treatment are to ob- tain and maintain an anatomic re- duction and avoid further damage to the physis. The form of treatment is determined by both the fracture type and the degree of displacement. For Salter-Harris type I and II injuries, nondisplaced fractures are immobilized for 4 to 6 weeks in either a long leg cast or hip spica cast. The duration of immobiliza- tion will vary with the age of the patient. Short, obese children, or patients who may be unreliable, are better managed in a spica cast. 4 Displaced fractures should be reduced under general anesthesia. Longitudinal traction can be used during the reduction maneuver to avoid further damage to the physis. Internal fixation makes subsequent displacement less likely, allows the use of a long leg cast with a greater margin of safety, and avoids the need to immobilize the knee in an extreme position of flexion or exten- sion to maintain the reduction. 4,5 Smooth transphyseal pins are used for type I injuries and for type II injuries with small metaphyseal fragments. Bending and burying the pins just beneath the skin can minimize the risk of bacterial contamination of the knee joint. Type II fractures with an adequately sized metaphyseal fragment may be stabilized using pins or AO cannu- lated screws across the metaphyseal portion of the fracture fragment (Fig. 3). Open reduction is indicated for any type I or II fracture that is irreducible by closed means. For Salter-Harris type III and IV injuries, nondisplaced and stable fractures may be managed by cast immobilization alone. Careful follow- up of these patients at weekly inter- vals is needed so that any displace- ment may be promptly addressed. Alternatively, these injuries may be stabilized using percutaneous pins or screws to minimize the risk of late displacement. Open reduction and internal fixation is indicated for all displaced type III and IV fractures to restore congruity of the joint surface and to align the physis. Because these are intra-articular fractures, full weight bearing is not begun until radiographs demonstrate adequate fracture healing. Outcome At most anatomic locations, a growth disturbance after a type I or II injury is rarely seen. However, when these fractures involve the distal femoral epiphysis, problems with shortening and angular deformity are more common. 4,6 Presumably this is because greater forces are required to disrupt the distal femoral physis, and the undulating shape of this growth plate renders it more sus- ceptible to damage by shearing and compressive stresses. Growth distur- Fractures Around the Knee in Children Journal of the American Academy of Orthopaedic Surgeons 346 Type I Type II Type III Type IV Type V Figure 1 The Salter-Harris classification 1 for fractures of the distal femoral epiphysis. The dashed line indicates the fracture line. (Reproduced with permission from Edwards PH Jr, Grana WA: Physeal fractures about the knee. J Am Acad Orthop Surg 1995;3:63-69.) bances are more likely to occur with fractures in younger patients and after fractures that are initially dis- placed more than one half the diame- ter of the shaft. 5,6 Riseborough et al 4 observed that fractures of the distal femoral epiphysis in patients 2 to 11 years of age were caused by more severe trauma and were more likely to lead to growth problems than sim- ilar fractures in adolescents. Careful clinical evaluation is rec- ommended at 6 months after the injury to detect physeal irregulari- ties that may suggest an impending growth disturbance. 7 Comparative radiographs of both lower extremi- ties are helpful for detecting these changes early. The patients should be followed at regular intervals until skeletal maturity because both growth deceleration 4 and growth stimulation 5 can occur after distal femoral physeal injuries. The precise amount of leg-length discrepancy that requires treatment remains controversial. Generally, leg-length inequalities estimated to be <2 cm at skeletal maturity can be managed nonsurgically. If the esti- mated discrepancy at maturity is 2 to 5 cm, an appropriately timed epiphysiodesis of the contralateral extremity may be indicated. For inequalities estimated to be >5 cm at maturity, leg lengthening should be considered. Significant angular deformity resulting from malunion or a partial growth arrest may be managed by osteotomy or by hemiepiphysiode- sis. When an osseous bridge is pres- ent, resection may be considered in children who have at least 2 years of growth remaining and whose lesions occupy <50% of the growth plate. MRI is now the imaging modality of choice to evaluate these lesions. Three-dimensional model- ing can be used to produce physeal maps that show the site and extent of the abnormality, which are useful for preoperative planning. 8,9 Oste- otomy combined with concomitant epiphysiodesis may be indicated in children who have larger physeal bridges or who are approaching skeletal maturity. Proximal Tibial Epiphyseal Fractures Classification The most commonly used classifi- cation system for fractures of the prox- imal epiphysis of the tibia is that of Salter and Harris 1 (Fig. 4). It corre- sponds to the system used for the dis- tal femur. Type I is a separation through the physis without involve- ment of the adjacent metaphyseal or epiphyseal bone. Type II traverses the physis before exiting obliquely across one corner of the metaphysis. These fractures are usually the result of a Lewis E. Zionts, MD Vol 10, No 5, September/October 2002 347 A D B C Figure 2 A 13-year-old boy sustained an injury to his right knee. Anteroposterior (A) and lateral (B) radiographs did not show a fracture. Sagittal T2-weighted (C) and axial fast spin echo (D) MRIs revealed a nondisplaced Salter-Harris type IV fracture of the proximal tibia (arrows). (Panels A–C reproduced with permission from Zionts LE: Fractures and dislocations around the knee, in Green NE, Swiontkowski MF: Skeletal Trauma in Children, ed 3. Philadelphia, PA: WB Saunders, in press.) Fractures Around the Knee in Children Journal of the American Academy of Orthopaedic Surgeons valgus stress with the metaphyseal fragment on the lateral side. Type III is a fracture through the physis that exits through the epiphysis into the joint. Type IV is a vertical, intra-artic- ular fracture through the metaphysis, physis, and epiphysis. These fractures may involve either the medial or later- al tibial plateau. Signs and Symptoms The patient with a fracture of the proximal tibial epiphysis presents with an effusion of the knee joint, local soft-tissue swelling, and ten- derness over the physis. Deformity is present in displaced injuries. Because of its close proximity to the proximal tibial epiphysis, the popli- teal artery is potentially at risk in these injuries. Posterior displace- ment of the tibial shaft in relation to the epiphysis, as may occur after a hyperextension injury, can produce a laceration or thrombosis of the popliteal artery (Fig. 5). Because the fracture may partially or completely reduce before the patient is evaluated, arterial injury must be considered in every patient with this injury. 10 The guidelines for evaluating children who sustain this injury are similar to those used for adults after a traumatic knee dislocation. A careful neurovascular examination must be done, documenting the presence of the dorsalis pedis and posterior tibial arterial pulses, the status of the distal perfusion of the limb, and the function of the poste- rior tibial and peroneal nerves. In an obviously ischemic extremity, the displacement should be reduced as soon as possible. If the vascular deficit persists, an arterial explo- 348 A DB C Figure 3 Anteroposterior (A) and lateral (B) radiographs of a Salter-Harris type II fracture (arrows) of the distal femur in a 9-year-old boy. Anteroposterior (C) and lateral (D) posttreatment radiographs. The fracture was stabilized using two AO cannulated screws across the metaphyseal portion of the fragment, supplemented by immobilization in a long leg cast for 4 weeks. Figure 4 The Salter-Harris classification 1 for fractures of the proximal tibial epiphysis. (Adapted with permission from Hensinger RN [ed]: Operative Management of Lower Extremity Fractures in Children. Park Ridge, IL: American Academy of Orthopaedic Surgeons, 1992, p 49.) Type I Anteroposterior view Lateral view Type II Type III Type IV ration should be performed imme- diately. In the absence of an obvi- ously ischemic limb, patients who have a diminished or absent pulse, or those who recover pulses and perfusion after reduction of the frac- ture, should undergo arteriogra- phy. 11,12 Ongoing evaluation of the lower extremity is important during the first few days after the fracture so that a developing compartment syndrome or intimal tear with throm- bosis may be detected promptly. Imaging Studies Anteroposterior and lateral radio- graphs usually reveal the fracture. When the plain radiographs appear to be normal, gentle-stress radiogra- phy or MRI may be used to detect a nondisplaced or otherwise obscure injury, as described for the distal femur. When stress radiographs are considered, hyperextension should probably be avoided. On occasion, CT may be used to evaluate and classify injuries more fully, especially in Salter-Harris type III and IV frac- tures that involve the articular sur- face 13 (Fig. 6). Treatment The goals of treatment are to obtain and maintain an anatomic reduction and to avoid further dam- age to the growth plate. For Salter- Harris type I and II injuries, nondis- placed fractures are immobilized in a long leg cast for 4 to 6 weeks, de- pending on the age of the patient. Displaced fractures are gently re- duced under general anesthesia to avoid further damage to the growth plate. Because many of these frac- tures are the result of hyperexten- sion injuries, flexion usually achieves reduction. Immobilization of the knee in marked flexion may increase the risk of vascular com- promise and thus should be avoid- ed. The use of internal fixation allows the knee to be immobilized in 20° to 30° of flexion, a position that poses less risk to the circulation and makes subsequent displace- ment not as likely. Smooth, crossed transphyseal pins are used for type I and II fractures with small meta- physeal fragments. Type II frac- tures with an adequately sized me- taphyseal fragment may be stabi- Lewis E. Zionts, MD Vol 10, No 5, September/October 2002 349 Figure 5 Lateral view of the knee showing the potential for popliteal artery laceration or thrombosis (arrow) after a hyperexten- sion injury to the proximal tibial physis. (Adapted with permission from Tolo VT: Fractures and dislocations around the knee, in Green NE, Swiontkowski MF [eds]: Skeletal Trauma in Children. Philadelphia, PA: WB Saunders, 1994, vol 3, pp 369-395.) Popliteal artery A D B C Figure 6 Salter-Harris type IV fracture of the proximal tibia in a 12-year-old boy. A, Anteroposterior radiograph does not demonstrate the fracture well (arrows). B, Coronal reconstruction CT scan shows the fracture line (arrows) more clearly. C, Axial CT view of the joint surface shows minimal displacement at the articular surface (arrows). D, The fracture was stabilized with two AO screws inserted percutaneously. lized using pins or AO cannulated screws across the metaphyseal por- tion of the fracture. Open reduction is indicated for irreducible type I and II fractures. Nondisplaced Salter-Harris type III and IV injuries may be placed in a long leg cast for 6 weeks. Careful follow-up of these patients at weekly intervals is necessary to address any displacement prompt- ly. Alternatively, cannulated screws may be inserted percuta- neously to stabilize these fractures (Fig. 6). Displaced fractures are treated by open reduction and internal fixation to restore con- gruity of the joint surface and to align the physis. After reduction, smooth pins or screws are inserted horizontally to avoid crossing the physis. Because these fractures are intra-articular, full weight bearing should not be allowed until radio- graphs show complete healing. Outcome In general, the prognosis for a closed fracture of the proximal tibial epiphysis is good. Shortening and angular deformity are uncommon because these fractures tend to occur in older children and adolescents and because the proximal tibial epiphysis contributes less to the overall growth of the limb than does the distal femur. Open injuries to the proximal tibial epiphysis have a much poorer prognosis. These fractures are often caused by lawnmower mishaps 10 that result in damage to the perichondral ring. Angular de- formities, either alone or in combina- tion with limb shortening, are com- monly seen after these open injuries. Tibial Tubercle Fractures Classification Watson-Jones 14 classified frac- tures of the tibial tubercle into three types. Ogden et al 15 modified this classification to include two subtypes, A and B, according to the severity of displacement and com- minution (Fig. 7). In type IA, the fracture is distal to the normal junc- tion of the ossification centers of the proximal end of the tibia and tuberosity. In type IB, the fragment is displaced (hinged). In type IIA, the fracture is at the junction of the ossification centers of the proximal end of the tibia and tuberosity. In type IIB, the fragment is comminut- ed and the more distal fragment is usually proximally displaced. Type III fractures extend into the joint. Type IIIA is not comminut- ed; type IIIB is. Signs and Symptoms Fractures of the tibial tubercle most often occur in males between 12 and 17 years of age. These injuries are most frequently associated with sports activities, particularly basket- ball and competitive jumping events. Injury is caused by either violent con- traction of the quadriceps muscle, as occurs with jumping, or acute pas- sive flexion of the knee against a con- tracted quadriceps muscle, as occurs when a football player is tackled. The patient with a fracture of the tibial tubercle presents with local soft-tissue swelling and tenderness directly over the tubercle. Patients with a type I injury usually are able to extend the knee against gravity, whereas those with a type II or III injury are unable to do so. Most of the patients with type II and III fractures have a hemarthrosis of the knee joint. Imaging Studies Accurate lateral radiographs of the tubercle are essential to evaluate this injury. Because the tubercle is just lateral to the midline of the tibia, the best profile is obtained with the leg in slight internal rota- tion. Oblique radiographs of the proximal end of the tibia are helpful to visualize fully the extension of the fracture into the knee joint. 15 Treatment Nondisplaced type I fractures (IA) can be treated successfully by immobilization in a cylinder cast or long leg cast with the knee in full extension for 4 to 6 weeks, followed by progressive rehabilitation of the quadriceps muscle. Displaced type I injuries, as well as nearly all type II and III injuries, are best treated by open reduction and internal fixation through a midline vertical incision. Any interposed soft tissue, such as a flap of periosteum, is removed to facilitate an accurate reduction. In all type III injuries, the menisci should be inspected for tears or peripheral detachments. Fractures Around the Knee in Children Journal of the American Academy of Orthopaedic Surgeons 350 Type IA Type IIA Type IIIA Figure 7 The Watson-Jones 14 classification of fractures of the tibial tubercle as modi- fied by Ogden et al. 15 (Reproduced with permission from Edwards PH Jr, Grana WA: Physeal fractures about the knee. J Am Acad Orthop Surg 1995;3:63-69.) Type IB Type IIB Type IIIA Osseous fixation may be achieved with pins or screws. Cancellous screws placed horizontally through the tubercle into the metaphysis afford stable fixation. Wiss et al 16 recommended the use of 4.0-mm cancellous screws rather than larger implants, such as 6.5-mm screws, to lessen the incidence of bursitis that may develop over prominent screw heads. Washers may be helpful to prevent the screw head from sinking below the cortical surface. The con- tinuity of the patellar ligament and avulsed periosteum is also repaired. If severe comminution is present, a tension-holding suture may be nec- essary to secure the repair. Postoperatively, the patient wears a cylinder or long leg cast for 4 to 6 weeks, followed by progressive reha- bilitation of the quadriceps muscle. Return to regular activities is permit- ted after the quadriceps has regained normal strength and a full range of motion of the knee joint has been achieved. Mirbey et al 17 permitted their patients to resume sports activi- ties at an average of 3 months after injury; however, after type II and III injuries, patients may require 16 to 18 weeks after cast removal to return to their preinjury activity levels. 15 Outcome The prognosis for a fracture of the tibial tubercle is very good. Compli- cations are uncommon. The theoretic complication of genu recurvatum has not been reported because most of these injuries occur when the physis is nearing normal physiologic clo- sure. Compartment syndrome, pre- sumably caused by tearing of nearby branches of the anterior tibial recur- rent artery, has been reported after tibial tubercle fractures. 16,18 Patients should be carefully monitored and those treated surgically considered for prophylactic anterior compart- ment fasciotomy. Bursitis over pro- minent screw heads that necessitates removal of the implant has been re- ported. 16 Tibial Spine Fractures Classification The anterior tibial spine, or emi- nence, is the distal site of attachment of the anterior cruciate ligament. Before ossification of the proximal tibia is complete, the surface of the spine is cartilaginous. When exces- sive stresses are applied to the ante- rior cruciate ligament, the incom- pletely ossified tibial spine offers less resistance than does the liga- ment, resulting in a fracture through the cancellous bone beneath the tibial spine. Traumatic forces that would cause a tear of the anterior cruciate ligament in an adult com- monly lead to a tibial spine fracture in a child. Meyers and McKeever 19 classi- fied tibial spine fractures into three main types (Fig. 8). In type I frac- tures, the fragment is minimally dis- placed, with only slight elevation of the anterior margin. In type II frac- tures, the anterior portion of the avulsed fragment has a posterior hinge and the anterior portion is ele- vated. In type III fractures, the avulsed fragment is completely dis- placed and may be rotated. Signs and Symptoms Fractures of the tibial spine usu- ally occur in children 8 to 14 years of age and are often the result of a fall from a bicycle. The patient with a fracture of the tibial spine typically presents with pain, a hemarthrosis, and a reluctance to bear weight. The knee may be held in a slightly flexed position because of hamstring spasm. Imaging Studies Anteroposterior and lateral radio- graphs will demonstrate a tibial spine fracture, with the degree of displacement best evaluated on the lateral view. Radiographs often un- derestimate the size of the avulsed fragment, which is largely cartilagi- nous. When routine radiographs show only small flecks of bone in the intercondylar notch, MRI may be useful to further assess the injury. Treatment Type I fractures and minimally displaced type II fractures may be treated by closed means. If a tense hemarthrosis is present, an aspira- tion of the knee joint should be per- formed under sterile conditions and a long leg cast applied. Although the Lewis E. Zionts, MD Vol 10, No 5, September/October 2002 351 Figure 8 The Meyers and McKeever 19 classification for tibial spine fractures. (Adapted with permission from Tolo VT: Fractures and dislocations around the knee, in Green NE, Swiontkowski MF [eds]: Skeletal Trauma in Children. Philadelphia, PA: WB Saunders, 1994, vol 3, pp 369-395.) Type I Type II Type III ideal position of immobilization is still the subject of some controversy, 10° of flexion seems to be an opti- mal position to immobilize the knee joint. Some authors have suggested immobilizing the knee in greater flexion to relax the anterior cruciate ligament. 19,20 Hyperextension prob- ably should be avoided so as not to compromise the distal circulation. Radiographs should be done to con- firm the reduction of the tibial spine fragment and repeated in 1 to 2 weeks to ensure that displacement has not occurred. The cast usually can be removed in 6 weeks and re- habilitation of the knee initiated. Surgical reduction, either arthro- scopically assisted 21,22 or through an anteromedial arthrotomy, is indicat- ed for irreducible type II fractures and all type III fractures. The ante- rior horn of the medial meniscus, if interposed, is removed from the fracture site to facilitate an accurate reduction. When reduction is per- formed through an arthrotomy, the fragment can be secured using an absorbable suture passed through the cartilaginous portion of the frac- ture fragment and the anterior tibial epiphysis. After arthroscopic reduc- tion, either an absorbable suture or cancellous screw can be used to fix the fragment. In an adolescent pa- tient with a small fragment, fixation may be achieved by weaving a non- absorbable pullout suture through the anterior cruciate ligament with the ends passed through drill holes in the anterior tibia. Postopera- tively, the knee is immobilized in 10° to 20° of flexion in a long leg cast. The cast is removed in 6 weeks and rehabilitation is begun. Outcome A good outcome may be expected for fractures of the tibial spine, at least in the short term. Nonunion of properly treated fractures is rare. Several authors have documented anterior cruciate laxity and some loss of full knee extension despite healing of the fracture in an anatomic position. 23-25 This laxity has been attributed to interstitial tearing of the anterior cruciate ligament that presumably occurs before the frag- ment is avulsed. Late laxity varies according to the severity of the ini- tial injury. Compared with type I injuries, greater laxity has been noted after type II and III frac- tures. 24 Despite the laxity, few patients complain of pain or insta- bility. Few long-term studies of this injury have been published. For an average of 16 years, Janarv et al 26 fol- lowed 61 children who had anterior tibial spine fractures. Although most of their patients had a good clinical result at long-term follow-up, these authors found no evidence to sug- gest that the anterior knee laxity resulting from the injury diminished over time. Because of the persistent laxity of the anterior cruciate liga- ment, which has been documented in several studies, 23-26 the long-term prognosis for this injury remains unclear, and parents of children with this injury should be appropriately counseled. Patellar Fractures Classification Patellar fractures rarely occur in children because the patella is largely cartilaginous and has greater mobil- ity than in adults. Ossification of this sesamoid bone does not begin until 3 to 5 years of age. 27 Most pa- tellar fractures occur in adolescents when ossification is nearly com- plete. 28 Fractures of the patella are gener- ally classified according to the loca- tion, pattern, and degree of displace- ment. Houghton and Ackroyd 29 described the so-called sleeve frac- ture that occurs through the carti- lage on the inferior pole of the patella (Fig. 9). This fracture occurs most commonly in children 8 to 12 years of age. A large sleeve of cartilage is pulled off the main body of the pa- tella along with a small piece of bone from the distal pole. The diag- nosis of this injury may be missed because the distal bony fragment is not readily discernible on radio- graphs. Grogan et al 30 observed that avulsion fractures can involve any segment of the patellar periphery. They described four patterns of in- jury: superior, inferior, medial (which often accompanies an acute lateral dislocation of the patella), and lateral (which they attributed to chronic stress from repetitive pull from the vastus lateralis muscle). Signs and Symptoms The patient with a fracture of the patella usually demonstrates local tenderness, soft-tissue swelling, and hemarthrosis of the knee joint. Active extension of the knee is diffi- cult, especially against resistance. A palpable gap at the lower end of the patella suggests the presence of a Fractures Around the Knee in Children Journal of the American Academy of Orthopaedic Surgeons 352 Articular cartilage Figure 9 Lateral view of a sleeve fracture of the patella. (Adapted with permission from Tolo VT: Fractures and dislocations around the knee, in Green NE, Swiontkow- ski MF [eds]: Skeletal Trauma in Children. Philadelphia, PA: WB Saunders, 1994, vol 3, pp 369-395.) sleeve fracture. A high-riding patella implies that the extensor mechanism has been disrupted. With marginal fractures, local ten- derness and swelling are present over the medial or lateral margin of the patella, and straight-leg raising may still be possible. The presence of an avulsion fracture of the medial margin suggests an acute patellar dislocation that may have reduced spontaneously. When an acute pa- tellar dislocation is suspected, other findings, such as tenderness over the medial retinaculum and a positive apprehension sign, also might be noted on physical examination. Imaging Studies Anteroposterior and lateral radiographs are necessary to evalu- ate fractures of the main body of the patella. Transverse fractures are best seen on the lateral view. A lateral radiograph taken with the knee in 30° of flexion may better ascertain the soft-tissue stability and true extent of displacement. 30,31 Small flecks of bone adjacent to the inferior pole in a patient who has sustained an acute injury may indi- cate that a sleeve fracture is pre- sent. MRI may be useful for diag- nosing a sleeve fracture when the diagnosis is not clear from the clini- cal and plain radiographic find- ings. 32 Marginal fractures that are oriented longitudinally may be best seen on a skyline-view radiograph. Treatment Treatment guidelines for patellar fractures in children are generally the same as those for adults. Closed treatment in a cylinder cast with the knee in extension is recommended for nondisplaced fractures, particu- larly if active extension of the knee is present. Surgical treatment is indicated for transverse fractures that show more than 3 mm of dias- tasis or step-off at the articular sur- face. 31,33 Fixation may be achieved using the AO tension band tech- nique, a circumferential wire loop, or interfragmentary screws. The retinaculum should be repaired at the time of osseous fixation. Partial or total patellectomy should be reserved for injuries with wide- spread comminution. Sleeve frac- tures should be accurately reduced and stabilized using modified ten- sion band wiring around two longi- tudinally placed Kirschner wires. Small marginal fractures are proba- bly best excised. If a large portion of the articular surface is involved, screw fixation of the fragment may be preferable to excision. Outcome The outcome after a fracture of the patella is generally good. Re- sults are poorer with fractures that show greater displacement and comminution. 28 If displaced frac- tures are not accurately reduced, complications can include patella alta, extensor lag, and quadriceps muscle atrophy. 31 Osteochondral Fractures Classification Osteochondral fractures of the knee are most often the result of a direct blow on a flexed knee or shearing forces associated with an acute dislocation of the patella. Rorabeck and Bobechko 34 described three fracture patterns following acute patellar dislocations in chil- dren: inferomedial fracture of the patella, fracture of the lateral fem- oral condyle, and a combination of the two. They estimated that osteo- chondral fractures occur in approxi- mately 5% of all acute patellar dislo- cations in children. Others have demonstrated a much higher rate of osteochondral fracture after acute dislocation of the patella in the pedi- atric age group. Nietosvaara et al 35 found associated osteochondral frac- tures, either capsular avulsions or intra-articular loose bodies, in 28 of 72 children (39%) after an acute dis- location of the patella. Stanitski and Paletta 36 reported arthroscopically documented articular injuries in 34 of 48 older children and adolescents (71%) after acute patellar dislocation. Signs and Symptoms The patient with an osteochon- dral fracture of the knee presents with a painful, swollen joint. The patient is reluctant to bear weight, and any attempt to flex or extend the knee is resisted. Tenderness may be elicited over the injured portion of the articular surface. A sterile aspi- ration of the knee joint is likely to yield a hemarthrosis and fat glob- ules, a finding that may suggest the presence of an osteochondral frac- ture somewhere in the knee. After an acute patellar dislocation, the pa- tient also may exhibit tenderness or a palpable gap along the medial patel- lar retinaculum and a positive appre- hension sign. Imaging Studies Osteochondral fractures may be difficult to see on plain anteroposte- rior and lateral radiographs, espe- cially if the ossified portion of the fragment is small. Oblique, skyline, and notch views should be obtained when an osteochondral fracture is suspected. Stanitski and Paletta 36 found that only 8 of 28 osteochondral loose bodies retrieved at arthroscopic examination (29%) could be identi- fied on a complete four-view radio- graphic series. Arthrography, CT, and MRI 37 may better visualize frag- ments that are largely cartilaginous. Treatment Most authorities recommend sur- gical management of acute osteo- chondral fractures of the knee. 31,34 Whether the fragment is excised or reattached depends on its size and origin. There is no agreement as to the size of the fragment that man- dates reattachment. In general, if the fragment is small and from a Lewis E. Zionts, MD Vol 10, No 5, September/October 2002 353 non–weight-bearing surface, it may be removed arthroscopically. Larger fragments from weight-bearing areas should be replaced. Numerous fixation techniques have been used with comparable results, including small, threaded Steinmann pins in- serted in a retrograde fashion, coun- tersunk AO minifragment screws, Herbert screws, fibrin sealant or other adhesives, and biodegradable pins. After reattachment, weight bearing should be avoided until radiographs confirm that healing of the fragment is complete. Outcome A good result may be expected after removal of small fragments that do not involve the weight-bearing surface of the joint. The outcome is less certain for large fracture frag- ments from a weight-bearing area. Complications include stiffness be- cause of adhesions and quadriceps muscle atrophy. Patients whose osteochondral fractures occurred as a result of an acute patellar disloca- tion may experience recurrent sub- luxation or dislocation. This compli- cation is most prevalent in patients whose first dislocation occurred in their early teenage years and in those with predisposing anatomic factors in the unaffected knee, such as passive lateral hypermobility of the patella, a dysplastic distal third of the vastus medialis obliquus mus- cle, and a high and/or lateral posi- tion of the patella. 38 Proximal Tibial Metaphyseal Fractures Classification Fractures involving the proximal metaphysis of the tibia are unusual injuries in children. The most com- mon type of fracture in this region is a minimally displaced, valgus green- stick injury. The fracture line usually extends two thirds of the way across the proximal metaphysis of the tibia although, in some instances, the frac- ture may extend completely across. Despite their innocuous appearance, these fractures often develop a pro- gressive valgus angulation during fracture healing as well as after union of the fracture. Signs and Symptoms These injuries are seen most often in children younger than 10 years of age and are usually the result of low-energy trauma. The patient with a minimally displaced fracture of the proximal metaphysis of the tibia presents with pain, swelling, and tenderness at the fracture site. Imaging Studies Anteroposterior and lateral radio- graphs usually reveal the fracture, which is most apparent on the an- teroposterior view. Treatment Minimally displaced fractures of the proximal tibial metaphysis may be treated by closed methods. Treat- ment is directed toward correcting the valgus angulation and closing the medial gap at the fracture site. The lower limb is immobilized in a long leg cast with the knee in exten- sion, and varus molding is applied to the fracture site. Healing is usually complete by 4 to 6 weeks. Outcome The most common problem asso- ciated with a minimally displaced fracture of the proximal tibial me- taphysis is progressive valgus angu- lation. The angulation occurs most rapidly during the first 12 months after the injury and continues at a slower rate for as long as 18 to 24 months. 39,40 It is important to em- phasize to parents the possibility of subsequent deformity despite ade- quate and appropriate treatment of the fracture. Although the exact cause of the deformity is not known, relative overgrowth of the medial portion of the proximal tibial physis, presum- ably because of fracture-induced hyperemia, probably plays a role. 41 In a series of children with posttrau- matic tibia valga, Ogden et al 39 found a generalized increase in lon- gitudinal growth of the injured tibia both proximally and distally, and an eccentric proximal medial over- growth in every patient. Early corrective osteotomy gener- ally is not indicated in the treatment of this problem because of the high rate of recurrence after osteotomy and the trend toward spontaneous improvement of the angulation as the child grows. 40 McCarthy et al 42 compared the results of surgical ver- sus nonsurgical treatment in a series of children with posttraumatic tibia valga. They found no significant difference in lower-extremity align- ment between the groups at the time of injury, at maximal deformity, or at latest follow-up. For an average of 15 years, Tuten et al 43 followed seven patients with posttraumatic tibia valga and found in all patients that spontaneous improvement of the angulation had occurred, result- ing in a clinically well-aligned, asymptomatic limb in most. They concluded that patients with this de- formity should be followed through skeletal maturity and that surgical intervention should be reserved for patients who have symptoms caused by malalignment. Summary Awareness of the unique types of fractures that occur around the knee of the growing child will allow the physician to make a prompt and accurate diagnosis, apply appropri- ate treatment techniques, and antici- pate potential problems. An ade- quate discussion with both patient and parents should emphasize the importance of follow-up care to allow early detection and manage- ment of any complications. Fractures Around the Knee in Children Journal of the American Academy of Orthopaedic Surgeons 354 [...]... Riseborough EJ, Barrett IR, Shapiro F: Growth disturbances following distal femoral physeal fracture-separations J Bone Joint Surg Am 1983;65:885-893 5 Thomson JD, Stricker SJ, Williams MM: Fractures of the distal femoral epiphyseal plate J Pediatr Orthop 1995;15: 474-478 6 Lombardo SJ, Harvey JP Jr: Fractures of the distal femoral epiphyses: Factors influencing prognosis: A review of thirty-four cases... Ogden JA, Ogden DA, Pugh L, Raney EM, Guidera KJ: Tibia valga after proximal metaphyseal fractures in childhood: A normal biologic response J Pediatr Orthop 1995;15:489-494 40 Zionts LE, MacEwen GD: Spontaneous improvement of post-traumatic tibia valga J Bone Joint Surg Am 1986;68: 680-687 41 Zionts L, Harcke HT, Brooks KM, MacEwen GD: Posttraumatic tibia valga: A case demonstrating asymmetric activity... Smith JB: Knee instability after fractures of the intercondylar eminence of the tibia J Pediatr Orthop 1984;4:462-464 Baxter MP, Wiley JJ: Fractures of the tibial spine in children: An evaluation of knee stability J Bone Joint Surg Br 1988;70:228-230 Willis RB, Blokker C, Stoll TM, Paterson DC, Galpin RD: Long-term follow-up of anterior tibial eminence fractures J Pediatr Orthop 1993;13:361-364 Janarv PM,... McKeever FM: Fracture of the intercondylar eminence of the tibia J Bone Joint Surg Am 1970;52:1677-1684 Fyfe IS, Jackson JP: Tibial intercondylar fractures in children: A review of the classification and the treatment of malunion Injury 1981;13:165-169 Mah JY, Adili A, Otsuka NY, Ogilvie R: Follow-up study of arthroscopic reduction and fixation of type III tibial-eminence fractures J Pediatr Orthop 1998;18:475-477... Watson-Jones R (ed): Fractures and Joint Injuries, ed 4 Baltimore, MD: Williams & Wilkins, 1955, vol 2, pp 751-800 15 Ogden JA, Tross RB, Murphy MJ: Fractures of the tibial tuberosity in Vol 10, No 5, September/October 2002 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 adolescents J Bone Joint Surg Am 1980;62:205-215 Wiss DA, Schilz JL, Zionts L: Type III fractures of the tibial tubercle in adolescents J... Ogden JA: Avulsion fractures of the patella J Pediatr Orthop 1990;10:721-730 31 Beaty JH, Kumar A: Fractures about the knee in children J Bone Joint Surg Am 1994;76:1870-1880 32 Shands PA, McQueen DA: Demonstration of avulsion fracture of the inferior pole of the patella by magnetic resonance imaging: A case report J Bone Joint Surg Am 1995;77:1721-1723 33 Ray JM, Hendrix J: Incidence, mechanism of injury,... JA: Growth slowdown and arrest lines J Pediatr Orthop 1984;4: 409-415 8 Borsa JJ, Peterson HA, Ehman RL: MR imaging of physeal bars Radiology 1996;199:683-687 9 Craig JG, Cramer KE, Cody DD, et al: Premature partial closure and other deformities of the growth plate: MR imaging and three-dimensional modeling Radiology 1999;210:835-843 10 Burkhart SS, Peterson HA: Fractures of the proximal tibial epiphysis . com- munication with the child’s par- ents. Distal Femoral Epiphyseal Fractures Classification The most commonly used system to classify fractures involving the distal femoral epiphysis is that of Salter and. classifi- cation system for fractures of the prox- imal epiphysis of the tibia is that of Salter and Harris 1 (Fig. 4). It corre- sponds to the system used for the dis- tal femur. Type I is a separation through. and the function of the poste- rior tibial and peroneal nerves. In an obviously ischemic extremity, the displacement should be reduced as soon as possible. If the vascular deficit persists, an