A patellar tendon rupture is a rupture of the tendon that
connects the patella to the tibia. Rupture often occurs at the lower pole
insertion site of the patella and it could be associated with degenerative
changes. Rupture most often occurs in patients younger than 40 years of age.
When the tendon is ruptured, the quadriceps muscle pulls the patella upward.
One way to measure the height of the patella is by measuring the Blumensaat’s
line. The knee needs to be flexed at least 30 degrees, then a line can be drawn
through the roof of the intercondylar notch and usually touches the tip of the
patella. The patella moves upward with the patellar tendon rupture (patella
alta).
Associated Risk Factors
- Rheumatoid Arthritis
- Diabetes
- Chronic Renal Failure
- Systemic Corticosteroid Therapy
- Chronic Patellar Tendonitis
- Degenerative Changes
During the radiographic evaluation, an AP and Lateral x-ray
is necessary. The patella alta is seen on the lateral view (*patella superior
to Blumensaat’s line). An MRI is effective in assessing the patellar tendon,
especially if other intraarticular or soft tissue injuries are suspected.
Treatment consists of a surgical reattachment of the tendon.
The patient will need to keep their knee in extension and in a knee immobilizer
for about 4-6 weeks.
