Tibial tubercle fracture

Uncommon injury

The tibial tuberosity develops as a structural modification of the anterior portion of the tibial epiphysis. The secondary ossification center of the tuberosity extends proximally toward the proximal tibial physis, and this cartilaginous bridge between the two centers fuses by the age of 17 years.

Avulsion fractures of the tibial tubercle tend to occur in older teenagers while jumping.

Distinguish these injuries from the Osgood-Schlatter lesion, which is a chronic stress avulsion.

As with patella sleeve fractures, damage to adjacent tissues may be more severe than radiographs indicate. 

 

Classification

 

Watson-Jones (1955) described three types of avulsion fractures of the tibial tuberosity.

  • Type I, a small fragment of the tuberosity is avulsed and is displaced upward.

  • Type II, the whole lip formed by the anterior aspect of the tibial epiphysis is hinged upward without being completely fractured at its base.

  • Type III, the entire tibial tuberosity is fractured at its base, with the line of fracture directed proximally and posteriorly into the articular surface.

Modified by Ogden et al.1980  to place more emphasis on intra-articular extension of the fracture and comminution of the tuberosity. They divided each of the three Watson-Jones types into two subclasses

  • Type I -  Separation through the distal portion of the physis under the tubercle breaks up proximally through the secondary ossification center of the tubercle. Type 1A - incomplete separation of the fragment from the metaphysis, Type 1B - complete separation

  • Type II - Separation extends anteriorly through the area bridging the ossification centers of the tibial tubercle and the proximal tibial epiphysis.Type 2A - fracture without comminution, Type 2B - fracture with comminution

  • Type III - Separation beneath the tubercle propagates through the proximally proximal tibial epiphysis into the knee joint under the anterior attachments of the menisci.Type 3A - single displaced fragment Type 3B - comminuted displaced fragments.

Treatment

 

Undisplaced/ minimally displaced - conservative above knee cast knee in extension, 6 weeks

 

Displaced - surgical repair.

 

Complications

Growth disturbance is rare and not usually a problem in children over 11 years of age.

Genu recurvatum may develop following the rare tubercle fracture that occurs before the age of 11.

 

Compartment syndrome has been reported in association with type-III fractures, presumably as result of bleeding from the anterior tibial recurrent artery .

 

References

Imaging Features of Avulsion Injuries; Radiographics. 1999;19:655-672.); Max A. Stevens, Georges Y. El-Khoury, Mary H. Kathol, Eric A. Brandser and Shirley Chow

Ogden JA, Tross RB, Murphy MJ. Fractures of the tibial tuberosity in adolescents. JBJS - A, 1980;62: 205-15.

Last updated 11/09/2015