Arthritis Treatment: The Three Types of Tendonitis That Cause Knee Pain And How to Treat Them

Knee pain (KP) is a common malady often seen in a rheumatologist's or orthopedic surgeon's office. Multiple causes exist including trauma, arthritis, bursitis, neurological conditions, genetic issues, and so on.

One type of medical problem causing KP that is frequently ignored... or not considered is tendonitis. There are at least three major types of tendonitis that can cause significant KP.

The first is quadriceps tendonitis. The quadriceps tendon connects the quadriceps muscle in the thigh to the patella (kneecap). While relatively uncommon, certain factors can cause quadriceps tendonitis to rear its ugly head. These include trauma, rheumatoid arthritis, gout, steroid therapy, kidney disease, and the use of fluoroquinolone antibiotics. The latter cause is an important one because fluoroquinolone antibiotics are frequently used to treat respiratory tract and urinary tract infections. These antibiotics can cause not only tendonitis but can also increase the likelihood of tendon rupture.

Quadriceps tendon rupture is devastating and can be recognized when a patient who has had symptomatic quadriceps tendonitis cannot straighten their leg, and there is a gap between where the tendon should insert into the kneecap and the quadriceps muscle. This is a surgical emergency.

Patellar tendonitis is another type of tendonitis that causes KP. It is fairly common, particularly in athletes who engage in running, jumping, and kicking. Patellar tendonitis is often referred to as "jumper's knee". Pain, tenderness, and inability to straighten the knee are usually present. Like the quadriceps tendon, this tendon can also rupture.

Both forms of tendonitis present with pain either above or below the knee cap. Treatment involves the use of rest, ice, anti-inflammatory drugs, physical therapy, stretching, and platelet-rich plasma. Platelet-rich plasma or PRP is an ultra-concentrate of blood containing many platelets. Platelets are blood cells that enable clotting and also contain many healing and growth factors. Multiple studies have demonstrated that ultrasound guided platelet-rich plasma injection can significantly shorten the healing cycle.

Another type of tendonitis that can cause knee pain is hamstring tendonitis. Although hamstring injuries in athletes are frequently due to hamstring muscle strain, hamstring tendons can also cause pain. The hamstring muscles originate at the back of the pelvis. They end in tendons that insert at the back of and along the inside part of the knee. When they become inflamed or injured, they cause significant pain and disability.

Treatment includes, rest, ice, anti-inflammatory drugs, physical therapy, gentle stretching and ultrasound-guided platelet-rich plasma injections.