The patellar tendon attaches the patella (knee cap) to the
top of the tibia. The quadriceps muscle is attached superiorly to the patella.
A small part of the quadriceps tendon then continues over the front of the
patella to become the patellar tendon. The patellar tendon works with the
quadriceps tendon to straighten the leg. Several bursae are seen around the
patella: suprapatellar, prepatellar, and infrapatellar. These bursae allow the
knee cap to slide freely underneath the skin while bending and straightening
the knee. Patellar tendonitis may develop due to repeated stress being placed
on the patellar tendon. Patellar tendonitis is often referred to as “jumper’s
knee”. It is an overuse condition that often occurs in athletes who perform
repetitive jumping activities. Patellar tendonitis is a knee pain that is
associated with focal patellar tendon tenderness, and it is usually activity
related. Younger adults will get patellar tendonitis. Older adults will get
quadriceps tendonitis. Jumper’s knee can occur above the patella, below the
patella, or at the tendon insertion into the tibia. The most common area for
patellar tendonitis (jumper’s knee) to occur is just below the knee cap.
Patellar tendonitis affects about 20% of jumping athletes. Patellar tendonitis
will cause anterior knee pain at the inferior border of the patella with
tenderness to palpation at the distal pole of the patella in extension and not
in flexion. Patellar tendonitis is a sport specific problem. Examples of sport
activities that are typically associated with patellar tendonitis include
basketball, volleyball, soccer, and it also may occur in runners. It occurs in
younger age athletes, taller body stature, higher body weight, and occurs more
in male volleyball players. Predisposing factors include quadriceps
inflexibility and atrophy, hamstring tightness, playing on a hard surface,
increased training frequency, or patellar hypermobility. Patellar tendonitis
occurs due to irritation of the tendon, and it progresses to tearing and
degeneration of the tendon. It is degeneration and not inflammation. The
condition causes micro tears of the tendon due to repetitive, eccentric
forcible contraction of the extensor mechanism with poor flexibility of the
hamstrings and quadriceps. Hamstring inflexibility places excessive stress on
the extensor mechanism which causes increased forces on the patellar tendon
during contraction. We should focus on screening and treating poor quadriceps
and hamstring muscle flexibility to prevent patellar tendonitis in athletes.
X-rays will appear normal. MRI and ultrasound will show degenerative changes in
the tendon and tendon hypertrophy. Ultrasound with colored doppler may show
increased vascularity. Examine the patient for flexibility of the lumbar spine
as well as the hamstrings and quadriceps muscles. Stiffness may cause patellar
tendonitis. Treatment is rest, anti-inflammatory medications, stretching and
strengthening (stretch the hamstrings and the quadriceps and use eccentric
exercise program). A patellar tendonitis strap can help relieve knee pain
caused by patellar tendonitis. Early stages of patellar tendonitis will respond
well to nonoperative treatment. Treatment can also be injections. Do not inject
steroids into the tendon, it may rupture the tendon. If you think injection is
necessary, inject around the tendon. Surgery is done in severe cases. It is
debridement and repair of the tendon. If conservative treatment fails for 6-12
months, then surgical treatment is indicated. When the patient continues to
have pain during activity and rest, then conservative treatment won’t work.
Surgery consists of excision of the degenerated parts of the tendon at the
inferior pole of the patella. At 12 months, 90% of the athletes return to
pre-injury level of activity.
