General categories of the knee involve either injuries or conditions. This is based on a given history of injury versus lifetime and activities including hereditary, body habitus, and other contributory factors. The Orthopedic physician’s job is to determine the anatomic factors affecting and producing patient complaints. This is generally divided into the following anatomic structures about the knee joint and in combination with the histories helps to determine the problem.
- Meniscus Cartilage
- Articular Cartilage Injuries And Conditions
- Ligaments Of The Knee
- Patellofemoral Joint
The meniscus consists of a poorly vascularized, ”C” shaped cushion that supports the weight-bearing characteristics of the knee joint. It consists of two menisci, one lateral and one medial. They are prone to rotational stress as well as cumulative wear. Injuries of the meniscus produce tears of various shapes and in combination with other associated injuries such as ligaments may suffer large tears. This often results in pain, catching, locking, and swelling of the knee joint determined by the location of the tear. Patients who are involved in higher impact activities over lifetime may also induce degenerative wear and subsequent tears of the meniscus in a similar pattern. Most meniscus injuries and conditions require removal of the unstable portion of the meniscus and repair is limited to very particular vascularized areas in young adults.
Articular Cartilage Injuries And Conditions
The articular cartilage is the surface covering of the ends of the bones joining at the knee (femur and tibia). This tissue is vulnerable to wear and tear in a similar fashion to the meniscus and is commonly affected by general aging in the population over 40 years of age. Articular cartilage is also an avascular or poorly nourished tissue. When injured some can be repaired by various surgical techniques for the knee including but not limited to substitute tissue grafts, procedures known as microfracturing, and in the future, regenerative growth techniques. Generally though, articular cartilage develops a wear pattern of the portion of the “tread” of the surface and remains a contributing factor leading to early arthrosis of the knee joint and is responsible for swelling of the knee (water on the knee) leading to stiffness and weakness and orthopedic evaluation.
Ligaments Of The Knee
Quite complex, there is a series of four ligaments that support the knee joint. The cruciate ligaments (“crossing”) are central to the knee joint and are of two types, one anterior and one posterior based on their anatomic attachments. They provide rotational stability of the knee or the main restraints in athletic activity. There are two lesser ligaments known as the medial and lateral collateral ligaments, which support the sides of the joints and are equally important in stability in athletic activities. Injuries to any of these joints are significant typically require an injury mechanism of sufficient force that produces simultaneous injuries to the above-mentioned cartilages or menisci. Most of these injuries result in significant bleeding or swelling of the knee joint and immediate orthopedic evaluation to fully assess the significance of the injury as well as for determining treatment course.
The patellofemoral joint or the kneecap gliding on its receiving surface is commonly involved in running conditions, flexion, squatting-type occupations and is recognized as the earliest site of arthritis development in age-related populations. Symptoms include difficulty on stairs, kneeling, and squatting and also is accompanied by swelling. Treatment of patellofemoral problems typically is conservative using various orthopedic measures to control inflammation and restore function.