Tack, Lieven

Van Crombrugge, Kris

Vanhoenacker, Charlotte

Vanhoenacker, Filip

English

Ghent University Academic Bibliography

Case 14039 Avulsion fracture of the tibial tubercle in an adolescentCharlotte Vanhoenacker , Kris Van Crombrugge , Lieven Tack , Filip Vanhoenacker 1 2 2 2, 3, 41: Leuven University Hospital, Department of Radiology, 3000 Leuven, Belgium2: AZ Sint-Maarten Duffel-Mechelen, Departments of Orthopedic Surgery, Emergency andRadiology; Leopoldstraat 2, 2800 Mechelen, Belgium3: Ghent University Hospital, Department of Radiology; De Pintelaan 185, 9000 Ghent, Belgium4: Antwerp University Hospital, Department of Radiology; Wilrijkstraat 10, 2650 Antwerp,Belgium University Hospital Antwerp  Musculoskeletal System Section: 2016, Sep. 20 Published: 13 year(s), malePatient:Clinical HistoryA 13-year-old boy presented to the emergency department of our hospital with a painful, swollenleft knee after high jumping in gym class. During take-off, he felt a sudden snap in his knee, afterlanding he was unable to bear weight. Clinical examination revealed the impossibility to extend theknee.Imaging FindingsLateral radiograph revealed soft tissue swelling and an enlargement of the growth plate of thesecondary ossification center of the tibial tubercle (Fig. 1).Subsequent MRI was performed for further evaluation of the extent of the lesion. MRI confirmedthe presence of an avulsion fracture of the secondary ossification center of the tibial tuberosity. Themaximum gap of the growth plate was located anterolaterally and measured seven millimeters. Inthe ventral part of the proximal tibial epiphysis, bone marrow edema was visualized in keeping withlesion extension in the femoro-tibial joint space (Fig. 2). Haemorrhagic effusion of the deep tibialtubercle bursa and the infrapatellar subcutaneous bursa was seen as well.DiscussionAn avulsion fracture is caused by a high energy tensile force on a ligament or tendon which exceedsthe strength of the bony tissue. In adolescents the growth plate is the weakest link, in comparison toadults whereas a tensile force will cause injuries of the musculotendinous junctions [1]. Typicallyavulsion fractures occur in boys between the age of 13-17 years because of the cartilage features ofthe growth plate. Avulsion fractures of the knee are uncommon compared to avulsion fractures ofthe hip or the pelvis [2]. Fractures of the apophysis of the proximal tibia comprise 0, 5% -3% of allfractures [3].The mechanism of injury is thought to be a high energy extension of the knee against a fixed leg,such as in jumping sports [4].Avulsion fractures of the tibial tubercle (TT) are classified according to the modified Watson-Jonesclassification (Fig. 3). The original classification of Watson and Jones described three categories ofavulsion fractures of the tibial tubercle [5]. Ryu and Debenham introduced an additional fourthcategory in which the fracture extends into the proximal tibial epiphysis. The extent of the injury isrelated to the stage of fusion of the epiphysis [6].Plain radiographs are the first step to define the displacement of the fracture, the degree ofcomminution and the extent of the injury[1].Although MRI is not always mandatory, it may be of additional value to define the precise extent ofthe bone and soft tissue abnormalities, and allows more accurate classification of the lesion. In ourcase, plain radiograph showed an enlargement of the growth plate of the TT. In addition, MRIrevealed bone marrow edema in the ventral part of the proximal tibial epiphysis indicating lesionextension in the articular surface of the tibia. After MRI the lesion was classified as a type IIfracture.The treatment, either conservative versus surgical, depends on correct staging of the lesion. Ifdisplacement is marked or if the physis is comminuted, surgical approach is recommended [7]. Inour case the maximum gap of the growth plate measured seven millimeters, therefore surgicalrepair, consisting of open reduction and internal fixation with cortical screws, was performed,followed by six weeks of immobilization in a plaster cast.Further follow-up was uneventful five months after trauma.TAKE HOME MESSAGEAlthough rare, avulsion fracture of the TT should be considered in sportive adolescents particularlyin jumping. MRI may add in correct staging of the lesion.Final DiagnosisAcute avulsion fracture of the apophysis of the tibial tubercle.Differential Diagnosis ListPatellar tendon rupture , Osgood-Schlatter diseaseFiguresFigure 1 Plain radiograph of the left knee: Anteroposterior and Lateral viewLateral view: Soft tissue swelling (red arrow) and broadening of the growth plate of theapophysis of the tibial tubercle (yellow star). © Vanhoenacker F, Department of Radiology, AZ Sint Maarten, Mechelen, Belgium. Area of Interest: Musculoskeletal joint;  Imaging Technique: Plain radiographic studies;  Procedure: Diagnostic procedure;  Special Focus: Trauma; Figure 2 MRI scan: sagittal T1 and T2 weighted images1. Undulating course of patellar tendon (red arrow), adjacent soft tissue swelling. Bonemarrow edema in ventral proximal tibial epiphysis (yellow arrow) indicating lesionextension in the knee joint. 2. Broadening of the growth plate (star). © Vanhoenacker F, Department of Radiology, AZ Sint Maarten, Mechelen, Belgium Area of Interest: Musculoskeletal joint;  Imaging Technique: MR;  Procedure: Diagnostic procedure;  Special Focus: Trauma; Figure 3 Modified Watson-Jones classification [5]I: Upward displacement of tibial tubercle (TT). II: Fracture extension through the articularsurface. III: Upward displacement of TT together with ossified part of tibial epiphysis. IV:Fracture through growth plate of proximal tibial epiphysis. © Vanhoenacker F, Department Radiology, AZ Sint Maarten, Mechelen, Belgium Area of Interest: Musculoskeletal bone;  Imaging Technique: Conventional radiography;  Procedure: Normal variants;  Special Focus: Trauma; Figure 4 Postoperative radiographs: Anteroposterior and Lateral viewThe avulsion fracture was treated surgically with open reduction and internal fixation withfour cortical screws. Postoperative x-ray shows correct alignment of fracture and correctposition of screws. © Vanhoenacker F, Department of Radiology, AZ Sint Maarten, Mechelen, Belgium. Area of Interest: Musculoskeletal joint;  Imaging Technique: Plain radiographic studies;  Procedure: Diagnostic procedure;  Special Focus: Trauma; References[1] Merrow AC, Reiter MP, Zbojniewicz AM, Laor T (2014) Avulsion fractures of the pediatricknee. Pedriatr Radiol 44:1436-1445[2] Singer G, Eber R, Wegmann H, Marterer R, Kraus T, Sorantin E (2014) ). Diagnosis andTreatment of apophyseal Injuries of the Pelvis in Adolescents Semin Musculoskelet Radiol 18(05):498-504[3] Crimaldi S, Calderazzi F, Becherucci L, Faidini A (2003) Upper tibial physeal fracture- a casereport. Proposed mechanism of injury and classification Acta Orthop Scand 74(6): 764-765[4] Clarke DO, Franklin SA, Wright DE (2016) Avulsion Fracture of the Tibial TurbercleAssociated With Patellar Tendon Avulsion Orthopedics 39(3): 561-4[5] Inoue G, Kuboyama K and Shido T (1991) Avulsion fractures of the proximal tibial epiphysisBr J Med 25(1)[6] Harb Z and Malhi A (2015) Bilateral Simultaneous Avulsion fractures of the Proximal tibia in a14-Year-Old Athlete with Vitamin-D Deficiency Case Rep Orthop[7] Subbu R, Nadra R, Jordan R et all (2013) Lessons learnt from managing an avulsion fracture ofthe tibial tubercle extending into the tibial physis BMJ Case RepCitationCharlotte Vanhoenacker , Kris Van Crombrugge , Lieven Tack , Filip Vanhoenacker 1 2 2 2, 3, 41: Leuven University Hospital, Department of Radiology, 3000 Leuven, Belgium2: AZ Sint-Maarten Duffel-Mechelen, Departments of Orthopedic Surgery, Emergency andRadiology; Leopoldstraat 2, 2800 Mechelen, Belgium3: Ghent University Hospital, Department of Radiology; De Pintelaan 185, 9000 Ghent, Belgium4: Antwerp University Hospital, Department of Radiology; Wilrijkstraat 10, 2650 Antwerp,Belgium (2016, Sep. 20)  Avulsion fracture of the tibial tubercle in an adolescent {Online}URL: http://www.eurorad.org/case.php?id=14039

Avulsion fracture of the tibial tubercle in an adolescent

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Avulsion fracture of the tibial tubercle in an adolescent

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