Runner’s knee is a term used to refer to a number of overuse injuries that cause pain (patellofemoral pain) in the front of the knee. This condition occurs mostly in runners, jumpers, and cyclists, but it can also occur in other athletes who place an increased amount of stress on their knees. Many runners? knee problems can be attributed to malalignment and structural asymmetries of the foot and lower leg, including leg-length discrepancy. The most common conditions are patellar tendonitis and patellofemoral syndrome that may lead to chondromalacia, pes anserine tendonitis or bursitis, and iliotibial band friction syndrome.
The patellar tendon connects the patella to the tibia in the front of the knee. The patellar tendon can become inflamed with activities such as running and jumping, causing pain.
The undersurface of the patella (kneecap) is covered with a layer of smooth cartilage; this cartilage normally glides effortlessly across the knee during flexion and extension. In individuals with this condition, chondromalacia often occurs. Chondromalacia is due to an irritation of the undersurface of the patella that results from the patella rubbing one side of the knee joint during knee range of motion (ROM). (For more information on patellofemoral syndrome, please return to the main menu and click on “Patellofemoral Pain Syndrome”).
Pes Anserine Tendonitis/Bursitis
The pes anserine is where the sartorius, gracilis, and semitendinosis muscles join and insert on the tibia. Pes anserine tendonitis is the inflammation of these muscle tendons at their insertion. Often associated with pes anserine tendonitis is pes anserine bursitis, which is inflammation of the bursa in this area.
Iliotibial Band Friction Syndrome
The iliotibial band (ITB) is a sheath of connective tissue attaching from muscles in the gluteal region to the lateral (outside) surface of the tibia. Its purpose is to extend (straighten) the knee joint as well as abducting the hip (moving it out sideways). Irritation of the ITB develops near the knee at the band?s insertion, and over the lateral femoral condyle where friction is created. The greatest friction on the ITB occurs when the knee is bent at an angle of approximately 20-30 degrees, which is the approximate angle of the knee when the foot strikes the ground during running, causing ITB friction syndrome to most commonly occur in runners. Treatment includes stretching the IT band and reducing inflammation.
Symptoms and Diagnosis
In patients who have persistent pain in the front or outside of their knee, an evaluation by an orthopaedic surgeon is warranted. The diagnosis of runner’s knee can be made with a combination of history, physical exam, and imaging studies.
Patients often complain of a dull, aching pain under or around the front of the patella (kneecap). Pain occurs when walking up or down stairs, kneeling, squatting, and sitting with a bent knee for a long period of time. For patient’s with IT band syndrome, pain is usually present on the outside of the knee (at or around the lateral epicondyle of the femur), and is aggravated with downhill running and flexion/extension of the knee. Mild swelling may also be present.
On physical exam, the surgeon evaluates the knee for swelling, any instability, and tenderness around the patella. Radiographs help determine if the patella is normally aligned within its groove (trochlea) in the knee. If cartilage injury is suspected, an MRI is usually obtained.
The treatment of runner’s knee depends on the specific problem(s) that is/are causing the pain. Initial treatment should always include the R.I.C.E. technique – Rest, Ice, Compression, and Elevation – which will help to reduce any inflammation that may be present. Stretching of the hamstrings and quadriceps muscles, and iliotibial band can be particularly helpful in alleviating the patellofemoral pain associated with runner’s knee; strengthening of the quadriceps muscles can also be beneficial in alleviating pain.
An evaluation of runner’s knee by a physical therapist can be particularly valuable. Physical therapists can help in determining the source of the pain, whether it is from a tendonitis/bursitis issue, patellofemoral syndrome, or IT band friction syndrome. A variety of treatment techniques, such as therapeutic modalities, soft tissue techniques, taping and/or bracing, and stretching/strengthening are used by physical therapists to help alleviate pain and symptoms.
Most cases of runner’s knee are successfully treated without surgery. If the pain is resulting from patellofemoral syndrome, surgery might be necessary to correct malalignment of the patella or damage to the cartilage under the kneecap. In cases where chondromalacia is present, and the cartilage on the underside of the patella is frayed, an arthroscopic procedure can be performed to clean up the frayed cartilage. If the patella is badly aligned a surgical procedure may be needed in order to realign the patella.
Written by Brian Feeley, MD