You are in: eMedicine Specialties > Orthopedic Surgery > KNEE Tibial Tubercle FractureArticle Last Updated: May 18, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Kelvin Lau, MA, BM BCh, DPhil, Senior House Officer in Trauma and Orthopedic Surgery, Department of Pediatric Orthopedics, Hospital for Sick Children, UK Kelvin Lau is a member of the following medical societies: Royal College of Surgeons of England Coauthor(s): Manoj Ramachandran, BSc(Hons), MBBS(Hons), MRCS(Eng), FRCS(Tr & Orth), Specialist Registrar, Department of Pediatric Orthopedic Surgery, Hospital for Sick Children, London Editors: Robert D Bronstein, MD, Associate Professor, Department of Orthopedic Surgery, University of Rochester School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Thomas M DeBerardino, MD, Director, John A Feagin, Jr Sports Medicine Fellowship at West Point, Clinical Instructor in Surgery, Orthopedic Surgery Service, Keller Army Community Hospital at West Point; Dinesh Patel, MD, FACS, Associate Clinical Professor of Orthopedic Surgery, Harvard Medical School; Chief of Arthroscopic Surgery, Department of Orthopedic Surgery, Massachusetts General Hospital; Carlos J Lavernia, MD, FAAOS, Adjunct Clinical Professor, Department of Orthopedic Surgery, University of Miami School of Medicine; Medical Director, Orthopedic Institute at Mercy Hospital Author and Editor Disclosure Synonyms and related keywords: tibial tuberosity avulsion, Osgood-Schlatter disease, tibial tuberosity apophysis INTRODUCTIONSection 2 of 11
  ProblemTibial tuberosity fractures are infrequent fractures affecting physically active adolescents. Activities involving powerful contraction of the knee extensors, such as springing and jumping movements, can result in avulsion fractures of the tibial tuberosity apophysis. This condition should be distinguished from Osgood-Schlatter disease, a chronic apophysitis of the tibial tuberosity due to recurrent traction injury. FrequencyIn the United States, the frequency of this injury is not known, although it occurs infrequently. At 1 major center, 15 cases of tibial tuberosity fractures were diagnosed in 5 years. Tibial tuberosity fractures typically occur in individuals aged 14-17 years. As the growth plate closes in late puberty, it is transiently replaced by fibrocartilaginous elements. These elements predispose the tibial tuberosity to traction injury as a result of its weakened tensile strength. Internationally, the frequency is not known. As in the United States, the condition occurs infrequently. EtiologyInjury from violent tensile forces on the tibial tuberosity causes this type of fracture. This is delivered through eccentric contraction of the extensor mechanism of the knee from either (1) violent contraction of the extensors without shortening (eg, springing off when jumping) or (2) forceful flexion of the knee against the powerful contraction of the quadriceps (eg, landing from a jump); in other words, it occurs when sudden acceleration or deceleration of the extensor mechanism occurs. Patients with Osgood-Schlatter disease may be predisposed to tibial tuberosity fractures. Similarly, patients with these fractures may have a family history of Osgood-Schlatter disease or a history of fractures of the tibial tuberosity. PathophysiologyThe proximal tibia has 2 ossification centers, the proximal tibial epiphysis and the tibial tuberosity, which are separated by a cartilage bridge (see Image 1). Before ossification, the tibial tuberosity is composed of fibrocartilage that has good tensile strength. However, during ossification, columnated cartilaginous cells with poor tensile strength replace the fibrocartilage, and it is within this small window between fibrocartilage and ossified matrix that the tibial tuberosity is at risk of avulsion fractures. As a result of the direction of pull of the patella tendon, the tibial tuberosity along with the proximal tibial epiphysis can be avulsed upward in a fracture in 1 or more fragments (see Image 2). Watson-Jones classified the fractures into the following 3 types:
Ogden further subdivided each class into types A and B. Type A fractures are single, and type B fractures are comminuted. ClinicalHistory The patient may have a history of Osgood-Schlatter disease in the affected and/or contralateral knee. This fracture is typically sustained during athletic activity and results in an acute onset of pain and swelling and in difficulty extending the knee. Physical The injury is almost invariably closed, with swelling and tenderness over the affected tibial tuberosity. Tibial tuberosity fractures are due to avulsion and not direct impact; therefore, injury to the overlying tissue is rare. In mild, or type I, injuries, the patient may be able to extend the knee against gravity, but he or she may not be able to extend it against resistance. In severe, or type II and type III, injuries, the patient may be unable to actively extend the knee. Type III (intra-articular) injuries are associated with hemarthrosis, and this manifests as a painful knee effusion following injury. A high-riding patella is suggestive of tibial tuberosity fracture. INDICATIONSSection 3 of 11
Nondisplaced type I injuries can be managed conservatively by cast immobilization in a long leg cast in full-knee extension. All other injuries are best treated by open reduction and internal fixation with cast immobilization for 6-8 weeks. RELEVANT ANATOMYSection 4 of 11
The extensor complex of the thigh exerts its force through the ligamentum patellae on the tibial tuberosity. During its histogenesis, the tibial tuberosity is an anterior extension of the proximal tibial epiphysis separated from the rest of the tibia by the growth plate. As the growth plate closes in late puberty, it is transiently replaced by fibrocartilaginous elements, which predispose it to traction injury as a result of its weaker tensile strength. WORKUPSection 5 of 11
Lab Studies
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Other Tests
Diagnostic Procedures
StagingThe fracture is classified into 6 subtypes to guide management. See Pathophysiology, above. TREATMENTSection 6 of 11
Medical therapyMedical therapy typically involves analgesia for pain control and thromboprophylaxis. The patient's discomfort can be controlled with acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs). If the pain continues, a narcotic analgesic can be added. Surgical therapyType IA injuries are treated conservatively with cast immobilization in full extension, followed by gradual rehabilitation of the quadriceps. Type IB, type II, and type III injuries are treated with open reduction and internal fixation. Type III injuries may also require exploration of the knee joint for meniscal and ligamentous damage, with accurate reduction of the intra-articular surface. Preoperative detailsThe surgical procedure is determined by type of fracture. The preoperative assessment is designed to identify the fracture, its displacement, and any associated injuries. Intraoperative detailsOpen reduction and internal fixation is the treatment of choice. The fracture is approached from an anterior or lateral parapatellar incision. Interposed soft tissue is cleared to promote accurate reduction. The tibial tuberosity is reduced and fixed to the tibia by using 1 or 2 screws. Arthroscopy or arthrotomy may be required to repair damaged menisci and to refashion a smooth articular surface, particularly in type III injuries. Postoperative detailsAnalgesia is required for control of postoperative pain. Physiotherapy is also part of the patients' postoperative care. Progressive rehabilitation of the quadriceps is required after cast immobilization. Physiotherapy and progressive weight-bearing exercises can be performed soon after open reduction and internal fixation is completed. Early mobilization attenuates joint stiffness and weakness due to prolonged immobilization. Follow-upAn orthopedic surgeon should follow-up patients to ensure the fracture is healing correctly and that any complications are managed. COMPLICATIONSSection 7 of 11
Complications are rare and include those related to trauma (eg, thromboembolism) or effects specific to the fracture. The latter includes meniscal damage in type III injuries, bursitis over metalwork, malunion, nonunion, recurrence, early degenerative change, genu recurvatum, and leg-length discrepancy. OUTCOME AND PROGNOSISSection 8 of 11
The prognosis is excellent, and most patients recover full function within a year. ACKNOWLEDGMENTSSection 9 of 11
The authors and editors of eMedicine gratefully acknowledge the contributions of previous coauthor Dr Fergal Monsell to the development and writing of this article. MULTIMEDIASection 10 of 11
REFERENCESSection 11 of 11
Tibial Tubercle Fracture excerpt Article Last Updated: May 18, 2006 | |||||||||||||||||||
