Introduction
A tibial tubercle avulsion fracture is usually an injury to the knee occurring in adolescence, during the transitional phase of physeal closure just prior to completion of growth. This fracture most often is an isolated injury related to push-off or landing while jumping as the quadriceps eccentrically contracts to support the individual's weight.
Diagrammatic view of tibial tubercle avulsion classification types I, II, and III.
Anteroposterior view of a type II tibial tubercle avulsion. The injury could be missed if a lateral view is not obtained.
Type III tibial tubercle avulsion. Note intra-articular fracture extension and anterior elevation.
The fracture tracks through the proximal tibial epiphysis and may extend into the anterior portion of the knee joint. The proximal tibia physis closes from posterior to anterior, and the fracture pattern is dependent on the amount of physeal closure present at the time of injury. Some authors consider this injury to be a variant of a Salter-Harris III fracture pattern. Open reduction and internal fixation is recommended, as reduction is difficult to maintain against the pull of the quadriceps muscle.
Problem
The difficulty with this fracture is in maintaining a satisfactory reduction against the proximal pull of the quadriceps muscle. The patient usually is very close to the end of growth, and fixation of the fragment should not affect remaining growth. In the rare instance in which this fracture occurs in a younger individual, suturing of the periosteum and retinaculum and temporary smooth Kirschner wire (K-wire) fixation may be performed.
Tibial tubercle avulsions have been classified as types I, II, and III.
Diagrammatic view of tibial tubercle avulsion classification types I, II, and III.
Type I injuries demonstrate minimal displacement and often can be treated with cast immobilization. Type II lesions maintain an intact superior contact between the avulsed portion of the tibial tubercle and the remaining portion of the tibial epiphysis. The articular surface of the knee is not disrupted. In type III injuries, the fracture extends through the articular surface of the knee with occasional meniscal disruption. Type II and III injuries require stabilization of the extensor mechanism through an open technique to replace the fragment and to remove any interposed periosteum. In type III injuries, exploration of the knee joint is necessary to address intra-articular comminution and meniscal pathology.
Frequency
Tibial tubercle avulsion fractures are commonly seen in athletic males (frequently basketball players) aged 14-16 years. These fractures account for 1-3% of physeal injuries.
Etiology
The mechanism of injury usually is an indirect force caused by sudden contraction of the quadriceps muscle. During sudden acceleration and deceleration forces, the quadriceps mechanism forcefully contracts against the patellar tendon insertion. When the force is greater than the strength of the tibial tubercle physis, a fracture is created, leading to avulsion of the tibial tubercle. Additional predisposing factors include patella baja, tight hamstrings, preexisting Osgood-Schlatter disease, and disorders involving physeal abnormalities.1
Pathophysiology
The tibial tubercle physis is in continuity with the tibial plateau. The physis progressively fuses from posterior to anterior, making it most vulnerable to avulsion in adolescents aged 13-16 years.
Presentation
The physical examination reveals swelling and tenderness over the anterior tibia. A palpable bone fragment and hemarthrosis may be present. With severe displacement, a high riding patella and loss of active knee extension are present.
Indications
Although a type I fracture may not be displaced, it is difficult to maintain this reduction against the pull of the quadriceps muscle. Close observation in the first 2 weeks is necessary. Often, percutaneous or open reduction can be performed to maintain motion within the knee.
Displaced types II and III avulsion fractures require operative fixation because of loss of the extensor mechanism length, tension, and continuity.2,3,4
Anteroposterior view of a type II tibial tubercle avulsion. The injury could be missed if a lateral view is not obtained.
Type III tibial tubercle avulsion. Note intra-articular fracture extension and anterior elevation.
Intraoperative view after open reduction and internal fixation of a type III tibial tubercle avulsion.
Type III fractures may demonstrate articular comminution and possible meniscal disruption requiring meniscal repair.
Relevant Anatomy
The proximal tibia physis progressively closes from posterior to anterior. The tibial tubercle is vulnerable to injury during the transitional phase of closure.
Contraindications
Type I fractures are minimally displaced and may be treated with cast immobilization. However, close observation is required.
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References
Cohen DA, Hinton RY. Bilateral tibial tubercle avulsion fractures associated with Osgood-Schlatter's disease. Am J Orthop. Feb 2008;37(2):92-3. [Medline].
Pesl T, Havranek P. Acute tibial tubercle avulsion fractures in children: selective use of the closed reduction and internal fixation method. J Child Orthop. Oct 2008;2(5):353-6. [Medline].
Abalo A, Akakpo-numado KG, Dossim A, Walla A, Gnassingbe K, Tekou AH. Avulsion fractures of the tibial tubercle. J Orthop Surg (Hong Kong). Dec 2008;16(3):308-11. [Medline].
Zrig M, Annabi H, Ammari T, Trabelsi M, Mbarek M, Ben Hassine H. Acute tibial tubercle avulsion fractures in the sporting adolescent. Arch Orthop Trauma Surg. Dec 2008;128(12):1437-42. [Medline].
Watson-Jones R. The classic: "Fractures and Joint Injuries" by Sir Reginald Watson-Jones, taken from "Fractures and Joint Injuries," by R. Watson-Jones, Vol. II, 4th ed., Baltimore, Williams and Wilkins Company, 1955. Clin Orthop Relat Res. Nov-Dec 1974;4-10. [Medline].
Ogden JA, Tross RB, Murphy MJ. Fractures of the tibial tuberosity in adolescents. J Bone Joint Surg Am. Mar 1980;62(2):205-15. [Medline].
Bolesta MJ, Fitch RD. Tibial tubercle avulsions. J Pediatr Orthop. Mar-Apr 1986;6(2):186-92. [Medline].
Christie MJ, Dvonch VM. Tibial tuberosity avulsion fracture in adolescents. J Pediatr Orthop. 1981;1(4):391-4. [Medline].
Roberts JM. Avulsion fracture of the proximal tibial epiphysis. In: Kennedy JC (ed). The injured Adolescent Knee. Williams & Wilkens: Baltimore;1979.
Roberts JM. Fractures and dislocations of the knee. In: Rockwood CA Jr, Wilkens KE, King RE (eds). Fractures in Children. JB Lippincott: Philadelphia;1984.
Kramer DE, Chang TL, Miller NH, Sponseller PD. Tibial tubercle fragmentation: a clue to simultaneous patellar ligament avulsion in pediatric tibial tubercle fractures. Orthopedics. May 2008;31(5):[Medline].
Further Reading
Related eMedicine topics
Tibial Tubercle Fracture (Orthopedic Surgery)
Tibial Plateau Fractures (Orthopedic Surgery)
Growth Plate (Physeal) Fractures (Orthopedic Surgery)
Compartment Syndrome, Lower Extremity
Clinical guidelines
Knee pain or swelling: acute or chronic.
ACR Appropriateness Criteria® acute trauma to the knee.
Clinical studies
Stem Cells and Tibial Fractures
TRial to Evaluate UltraSound in the Treatment of Tibial Fractures
Pulsed Electromagnetic Field (PEMF) Stimulation for Tibia Fractures
Splinting Versus Not Splinting of the Distal Lower Extremity After Intramedullary Nailing for Tibial Fractures
Keywords
tibial tubercle avulsion, tibial tubercle fracture, knee fracture
