Volume 4, Case 11
Loren G. Yamamoto, MD, MPH
Kapiolani Medical Center For Women And Children
University of Hawaiʻi John A. Burns School of Medicine
This is a 16-year old male who injured himself playing basketball. He was running backward when he tripped and fell directly onto his right knee with immediate severe pain. He was unable to ambulate. His past medical history is unremarkable.
Exam: VS T37.0 (oral), P88, R18, BP 130/50. He is alert. He is uncomfortable but not in acute distress. He is of average height and weight for his age. His right knee shows obvious swelling over his pre-patellar region. His patella is non-tender, but pushing on the patella results in some tenderness over his upper anterior tibia just below the patella. There is tenderness over the upper anterior tibia. There is no instability about the knee. The drawer sign is negative. His patella is not dislocated. There is no tenderness over his femur. There is no tenderness over his mid and distal tibia. His fibula is non-tender. There are no deformities. His pulses and sensation are intact distally. He is unable or unwilling to bear weight on his right leg. He says he can't move his knee on his own very well.
He is given some analgesics. Radiographs of his right knee are obtained.
View knee radiographs.
Clinically, he does not seem to have a patella fracture so a sunrise view of the knee is not obtained. His problem appears to be more distal, in the upper tibia. The AP view shows no abnormalities of the distal femur. The tibial plateau and the metaphysis appear to be normal. However, there is a bony fragment to the left of the image superimposed over the joint space.
The lateral view is more revealing in that it shows this bony fragment clearly resulting from an avulsion of the tibial tuberosity. The patellar tendon is not visible of course.
His knee is immobilized and he is placed on crutches. Orthopedic follow-up is arranged.
Osgood-Schlatter's disease results from repeated stress of the tibial tuberosity apophysis. It usually occurs in adolescents who jump a lot (basketball players and volleyball players). Repeated pulling on the quadriceps and patellar tendon at the insertion of the tibial tuberosity results in microfracture or stress fracture (apophysitis). This manifests as pain and tenderness over the tibial tuberosity during athletic activity.
In a more extreme injury, the tibial apophysis is at risk for avulsion. It may rupture fully or partially resulting from a forced flexion when the quadriceps is contracted, by extreme contraction, or from direct trauma (i.e., falling onto the tibial tuberosity). The typical history is that of sudden buckling of the knee with extreme pain. The pain subsides to some degree. If the patella is inferior to its usual position, this suggests a proximal rupture of the quadriceps tendon. If the patella is superior to its usual position, this suggests a patellar tendon rupture at the tibial tuberosity. Interestingly, the patient may be able to weakly flex and extend the knee despite the tendon rupture, but will not be able to hold up their lower leg against gravity.
Also of interest is that many of these injuries are missed on initial evaluation. Such patients may present with an old tendon disruption with complaints of knee buckling and inability to climb stairs. Patients with patellar tendon ruptures should be immobilized. Partial tendon ruptures can be treated conservatively with immobilization and casting. More severe tendon ruptures require early surgical repair.
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