Injuries and Conditions: Knee: Cartilage Defects: Medical Details
Overview As the bones of the knee come in contact with each other, they are insulated by a layer of cartilage that covers the contact points (articular surfaces) of the joint. Any degeneration or injury to this cartilage interrupts the smooth functioning surface of the knee and compromises the protective layer between bones. This cartilage can become worn after years of use or damaged through sudden twists or turns that fragment and/or dislodge pieces of cartilage.
Cartilage is found throughout the body, and depending upon its location, varies in its composition and structural qualities. In the ear or nose, it provides a flexible construction that can easily bend without harm or discomfort. In the knee, however, cartilage provides a surface covering the weight-bearing and functional bones of the knee. The soft and nearly frictionless cartilage allows the bones to fit together and move against one another with considerable ease while minimizing forces that may otherwise lead to degeneration.
Cartilage injuries represent a spectrum that range from localizied defects to widespread degeneration or osteoarthritis, which is seen in older individuals. In either case, once cartilage is injured, the body has only a limited ability to heal or repair damaged cartilage surfaces.
The severity and rate of degeneration varies from person to person. The process of cartilage degeneration occurs in all individuals to the point that approximately 60% of all sixty year-olds will have some fraying or tearing of articular cartilage. Fortunately, not all of these individuals will have symptoms.
Causes of Injury
Cartilage defects result from a combination of factors including heredity, intensity of athletic activity and the extent of previous injury.
Repetitive actions which pound or wear the knee from a particular motion can cause damage over time.
Any bio-mechanical problems with the leg will result in excessive wear: poor alignment of the upper and lower leg, over-pronation (in which the lower leg rotates inward due to the unstable pronated foot) or any muscle imbalances in the thigh can increase the likelihood for cartilage degeneration or the development of cartilage defects on a joint surface.
Cartilage can also be damaged from a traumatic event such as a sudden twist or blow to the knee.
Many patients with cartilage injury have a history of prior trauma to the knee, but this is not uniformaly present. Patients may typically complain of aching, pain, swelling, stiffness and possibly, locking or giving way within the knee. In some cases, relatively recent trauma may lead to a fragment of cartilage breaking off and floating around the knee leading to mechanical symptoms suchas locking or catching. Both the location of and the general movements associated with pain are used to diagnose the condition. Pain will generally occur when pressure or stress is put on the underside of the thighbone (femur). Squating or other movements that load the knee and cause pain may indicate damage.
Ahe physical examination of all knee structures of the knee will be performed, especially of the ligaments and meniscus cartilage, as the structures are often involved. The physical exam will focus on flexibility, motion, stability, and tenderness. Swelling may be present leading to limited flexibility. Knee motion may be associated with abnormal grating or grinding with or without the presence of pain. Stability assessment will be performed because injuries that cause ligament tears may also cause cartilage injury. An examination of the tissue and ligaments around the knee may demonstrate areas of tightness, sensitivity, or tenderness which may further suggest an injury to the cartilage of the knee.
Additional tests to view the location of the knee's structures can be used to assess the health of the cartilage and the positioning of the bones relative to one-another. These may include x-rays, magnetic resonance imaging (MRI), and arthroscopy, in which a small camera inserted through small incissions is used to visualize the structures within the knee.
Orthotics An orthotic insert fits inside a shoe and helps position the foot in an anatomically correct position while walking, running, or jumping. Frequently, abnormal foot motion and gait occurs as a result of over-pronation of the foot; most orthotics are used to treat this condition. Over-pronation is a tendency to roll the foot onto the inner edge, loading the inside of the foot and leaving the outer edge almost weightless. A professionally made orthotic insert will exactly contour to the bottom of the foot, and can compensate for over-pronation or other abnormal foot mechanics.
One of two construction methods may be used to create an orthotic; one utilizes a plaster mold of the entire foot to make a moderately rigid insert, the other utilizes a foam impression of the bottom of the foot, creating a more flexible insert. In either case, the finished product must be tilted with small wedges, while other accommodations are made to protect sensitive areas of the foot. The choice of orthotics and design will vary according to the expected use, foot type, and body weight.
Orthotics can be used to treat:
abnormal foot mechanics
patella dislocation or maltracking
general knee pain
Knee: Support A knee support is a sleeve-like support that fits firmly around the knee. The support is used to reinforce the joint during motion
and provide compression to aid healing and reduce pain and swelling.
Patients suffering from knee strains or inflammation will usually be
directed to use a support during daily activities.
The thin and flexible construction of the support allows for normal
movement of the knee and also allows the support to be worn under
loose fitting clothing. To prevent harmful pressure to certain
structures, the support applies differing compression around the
knee. The sides of the joint receive intermittent pressure to help
stimulate blood flow while the rear of the support fits relatively
loose to prevent constriction of circulation. The kneecap is aided
in positioning, but remains free of compression to allow its natural
Knee supports can be used to treat:
NSAIDs NSAIDs (Nonsteroidal Anti-Inflammatory Drugs) are a group of drugs used to control pain. This category of medications includes both prescription and common over-the-counter painkillers such as ibuprofen. NSAIDs are effective for many types of pain that can occur because of inflammation of muscles, joints and bones. The drugs work quickly and people often notice some benefit within a few hours of taking the tablet. However, the complete effectiveness of the drug may not be realized for up to four weeks. For each individual, some varieties of NSAIDs are more effective than others. Often, patients will find that one or two varieties are helpful whereas others may not be as effective in controlling symptoms. It is usually necessary to try several brands and continue with the one that is most suitable. NSAIDs can be used to treat: