Traumatic Knee Injury, Part 1

A study in the Annals of Internal Medicine indicates that by age 65, traumatic injury to the hip or knee joint sustained during childhood resulted in a higher incidence of osteoarthritis (about 14 percent) when compared to children who did not suffer hip or knee injury (six percent).

As discussed previously (,27082.asp), osteoarthritis is a degenerative condition of the synovial joint that may result from an antecedent trauma to the cartilage or soft tissues. In this regard, posttraumatic osteoarthritis in adults can be minimized by appropriate treatment of an injury sustained in children. A first consideration recommends bracing, which acts to stabilized the injured joint. Active physical exercise must temporarily be curtailed to minimize any additional damage to the joint as it heals. Most physicians advocate the use of braces and/or other orthotics when the child returns to high-impact physical activity.

Exercise-related knee injuries can take many forms. The health of the joint is jeopardized by damage to the cartilaginous and soft tissue structures. With respect to developing posttraumatic osteoarthritis as an adult, the knee, hip and shoulder are particularly sensitive, the ankle less so. Some injuries directly affect the articular cartilage and supporting cartilages of the joint such as the meniscus. “Runner’s knee” refers to the damage caused by a high level of running on the structures of the inside (medial aspect) of the knee. Overuse causes high levels of stress to the patella (kneecap) causing it to move from side to side over the groove in the femur resulting in a softening of the underlying articular cartilage. This condition is referred to as, “chondromalacia of the patella.”

The pain resulting from this damage may precede more serious damage to the underlying femoral articular cartilage where osteoarthritis may ensue. A differential diagnosis ruling out “patella tendonitis” is recommended before medical therapy is considered. Runner’s knee is generally treated conservatively. Treatment may include a reduction in running activity or complete rest if the pain and swelling do not subside. If a running regimen is maintained, the use of cold treatment (ice packs) is recommended with a 15 to 20 minute treatment followed by a warming-up time before reapplying the ice. Non-steroidal anti-inflammatory drugs such as aspirin or ibuprofen may also medically regulate pain and swelling. In the active runner, controlled physiotherapy also may be helpful, which, if combined with improved orthotics, can be employed to treat the over-pronation that contributes to the development of runner’s knee (also see,26687.asp). Since weak or under-developed quadriceps muscles and muscle imbalance can also contribute to the development of runner’s knee it is recommended that specific exercises be used to strengthen these muscle groups.

Warming-up prior to exercise can help prevent traumatic joint injury. With specific reference to the knee, stretching exercises are mandatory prior to beginning high-impact exercise or running. Stretching should be preceded by warm-up either by walking or employing a stationary bike. Weight training under supervision may also help strengthen important muscle groups. Marked and sudden changes in the exercise level should be avoided, as the joint does not generally respond well to this alteration in regimen.

What if the joint is injured? A general approach is to first have a physician assess the type of injury and make a determination as to which of the cartilaginous or soft-tissue structures have been damaged. Direct damage to articular cartilage, menisci, muscles, ligaments and tendons must be differentially assessed. The approach to treatment will also vary according to the type and intensity of the individual’s physical activity.

Damage to the knee is determined by a combination of techniques. The previous medical history is crucial since it is informative of the nature of the cause of the injury and any past injuries or general health considerations that might contribute to the course of therapy. The physical examination will generally include bending, straightening, rotating or pressing on the knee to determine the location and extent of injury. Diagnostic tests may be combined with X-ray to localize the degree of damage.

In some cases, a Computerized Axial Tomography (CAT) scan will be employed since this technique can determine the extent of soft-tissue injury better than X-ray.

If necessary, a bone scan (radionuclide scanning), which determines whether blood flow to the bone has been affected by trauma, can also be employed. If surgery is indicated, physicians may require a Magnetic Resonance Imaging (MRI) of the knee, which is sensitive to detecting damage to muscles and ligaments. Arthroscopy may also be indicated. In this procedure, an orthopedic surgeon or other qualified physician employs a small, lighted optic tube (arthroscope) inserted through the skin to visualize the damage to the joint. The damage may be accurately assessed and moreover, repaired, if necessary.