AVULSION FRACTURE OF THE TIBIAL TUBERCLE ASSOCIATED TO AN AVULSION OFTHE PATELLAR LIGAMENT

Purpose of the study Avulsion fracture of the tibial tuberosity is con sidered as a relatively uncommon adolescent injury. The avulsion of th e patellar ligament may occur as part of the injury. Two cases of sixt een year old boys with this kind of injury have been reported. Fractur es are described using Ogden et al. classification : type is an avulsi on fracture of the most distal portion of the ossification center of t he tubercle; type II, an upward angulation of the lip fragment; type I II, a fracture of the lip fragment with propagation of the fracture-li ne into the knee joint. Each type is subdivised into A (no comminution ) and B (comminution). Frankl et al, in 1990 address the possibility t hat patellar ligament avulsion may occur as part of the injury (type C ). Case reports Two sixteen-year old boys suffered from sharp pain in the knee during a jump while playing basketball. Radiographic evaluati on demonstrated an avulsion fracture of the tibial tubercle type III C . The osseous fragment was sutured with trans-osseous suture. The fixa tion was protected with a tension band passed above the patella and di staly in the tibia. It was removed at six weeks. One patient was not r eviewed and the other had no complain one year after. Discussion Avuls ion fracture of the tibial tuberosity Ogden type I and II is generaly treated by plaster cast. When the patient is unable to extend his knee actively, an avulsion of the patellar ligament should be suspected. I n this case, Frankl et al. proposed radiographic evaluation the distan ce between the distal end of the patella and the avulsed fragment was noted to increase during flexion. Avulsion of the distal tuberosity us ually occurs just prior to complete closure of the proximal tibial phy sis. Interfragmental transphyseal screws can thus be used safely. In t he younger patient or in extensive comminution, tension band wire shou ld be used. The use of a tension band between patella and tibia to pro tect the ligament reinsertion provise early knee mobilisation (between 0 and 60 degrees). It should be removed within six weeks. Conclusion Avulsion fracture of the tibial tuberosity is rare. When conservative treatment is indicated, it is important to search an avulsion of the p atellar ligament. When such an injury is suspected, lateral radiograph s of the knee should be made in flexion as well as in extension. We be lieve that treatment should include open reduction and internal fixati on associated with a protect tension band allowing early rehabilitatio n.