The Knee: Joint Structures, Functions, and Injuries
Man is one of the most complex organism in the face of the earth. His high intelligence quotient and his ability to speak, reason and solve problems is second to none in the mammalian world. Aside from his inherent capabilities the physical aspect of his being is also something that has to be appreciated. A simple scientific analysis of the eyes, the heart and brain will fill book shelves with mind-boggling information.
The complexity of the human body is evident in the examination of single organs but when different systems combine they can produce something truly fascinating. An example of a collaboration between two systems – the muscular and skeletal systems – is the knees, one of the most important and complex part of human anatomy. The following pages will deal with its basic structure, function, injuries and modern means of repairing the damage.
Structure & Function
According to Martha White, “The knee is one of the most complicated and vulnerable joints of the body. It is the connecting link and weight-bearing joint between the hip and the foot. Many factors unrelated to the knee joint itself contributed to its potential for injury” (year). A more technical definition was given by Moore and Dalley (2002) who wrote:
The knee joint is our largest and most superficial joint. It is primarily a hinge type of synovial joint, allowing flexion and extension; however, the hinge movements are combined with gliding and rolling and with rotation about a vertical axis. Although the knee joint is well constructed, its function is commonly impaired when it is hyperextended (e.g. in body contact sports, such as ice hockey).
The seemingly imperfect structure where the two ball-joints meet is also highlighted by Aigner and Gillquist who remarked, “The bony elements which form the static basis of the knee joint have very incongruent surfaces” but they also provided the solution to the problem, “Congruity between the surfaces is established by connective tissue structures” (1991). Later on it will be shown that the design allows for a wide range of movement all human beings but at the same time it is a major source of injuries and other problems.
There are also stabilizing structures on the medial side of the knee joint. With regards to the stabilizing effect of the connective tissues (static) the following structures are included (Aigner & Gillquist, 1991):
Medial collateral ligament
Now, with regards to the muscles (dynamic) the following structures are included:
Vastus medialis muscle
Muscles of the pes anserinus
On the lateral side of the knee joint, the stabilizing structures with regards to connective tissue (static) includes the following:
Lateral collateral ligament
With regards to the muscles (dynamic) the stabilizing work is made possible by the following (Aigner & Gillquist, 1991):
Biceps femoris muscle
Vastus lateralis muscle
Modern societies who are not ignorant of the wonderful world of sports are also privy to the fact that sports related injuries are common. In America where sports is sometimes compared to a modern day religion makes it easy for ordinary individuals to hear of news of injured star athletes. But even minus the professional leagues parents are well aware of the pain and suffering of sports related injury through the sports activities of their children. And there is none as frightening and excruciating than knee injuries simply because a non-functioning knee immobilizes a person permanently. Compare this with foot and ankle injuries wherein a simple solution such as braces and bandages will suffice. But not for the knee, functional knee is able to flex and help propel an individual. If this is missing then there is injury and if not treated soon the problem will even become worse as knees bear a great deal of weight even when the person is not moving and simply standing still.
K. Moore and A.M.R. Agur adds, “Knee joint injuries are common because the knee is a low-placed, mobile, weight-bearing joint and its stability depends almost entirely on its associated ligaments and muscles” (2007). As mentioned earlier a joint usually involves a ball and a socket but when it comes to the knee there are two “balls” one coming from a major bone connected to the hip and the other major bone is connected to the foot. One can just imagine two rounded portion of bones placed head to head. Now, combining these information with another that says the main support of these skeletal systems is in the muscles and ligaments one gets an idea as to why many athletes gets injured.
Injury can be the result of two major factors. One is the weakened state of the muscles related to the stability and function of the knee joint. As stated earlier the incongruence and awkward design of the knee relies on the proper working of related muscles to keep it stable and functioning well. So if a person is leading a sedentary life characterized by long hours spend in the cubicle (office work ) or spending inordinate time in front of the television set (or kids playing games) the muscles in the knees that are not continually strengthened or conditioned will experience atrophy. So when these individuals suddenly decided to play sports they get injured.
The other main factor that contributes to injuries is repetitive and extended use of the knees. This is the domain of professional athletes and even those who are in involved in team sports in many schools across America. Moore and Dalley were both correct in saying that even if the knee is well constructed, abuse and misuse will surely result in serious wear and tear.
The following are some of the most common injuries associated with the knee joint:
Medial Collateral Ligamentous Sprain – usually results from a direct blow to the outside of the knee, a common occurrence in sports like football where the athlete suddenly turns inside or it could be a “cutting move” as seen in skiing when the athlete suddenly decelerates. Sprains are classified into three differing degree of seriousness. The first degree level can be remedied by rest, ice, compression, and elevation. But with regards to the second and third degree, the one suffering this type of injury usually cannot straighten the leg completely.
Chondromalacia – in sports such as long distance marathon or even in triathlons the repetitive and extensive use of the knees can result in a grinding and painful sensation in the kneecap. This is aggravated also by repetitive flexion and extension – bending and straightening – of the knee. Even non-athletes can experience the same problem if there is repetitive use of the said joint such as in walking, ballet, or frequently going up and down stairs.
Patellar Subluxation or Dislocation – This problem can be a one-time incident or it could recur due to a number of conditions. The person may be experiencing problems such as knock-kneed posture, weak quadriceps, ligament laxity, flattened arches, or patellar misalignment where the patella is located outward of the midline of the knee (White, 1995).
Arthroscopy is the modern way of diagnosing knee problems. In the words of Aigner and Gillquist, “Arthroscopy is well established as a method of endoscopic examination of joints in orthopedic surgery” (1991). For a body structure of such complexity the availability of a device that can actually see the anatomy of the knee joint is a welcome relief – no need for guessing or unnecessary surgery.
All general term to refer to all living things is the word “organism”. This is obviously taken from the word “organization” because one can see the high degree of organization among the different systems of the body; even in the cellular level one can observe a high-level complexity. An implication of this observation is the fact that everything is interconnected. For instance the excretory system is dependent on the digestive system and vice versa.
In the case of the knee joint there is no way that this mechanism can function in isolation. In order for the knees to function perfectly, other parts of the body must also be in tip-top shape. This is more true when it comes to the relation of the knee to the foot-ankle dynamic. According to Dr. H. Winter Griffith, in the event of an ankle fracture, “Arthritic changes may also occur in the knee joint because an ankle fracture sometimes causes added stress on the knee due to changes in weight-bearing” (Griffith & Friscia, 2004).
A human being is an organism and he or she is part of that general category of living things because a person is the sum of a diversity of complicated systems. As mentioned earlier the digestive, excretory and even skeletal systems work in tandem in order to have a healthy human body able to do regular tasks.
This means that if one part is not functioning well then the rest of the body is affected. One of the most important part of the body in terms of movement is the knee joint. This portion of the body maybe small in comparison to other organs and structures but if the knees are injured life will not be as sweet. In fact terrible pain and immobility is something no one will wish upon their worst enemy.
The above discussions was an eye-opening tour to a commonly neglected part of the body the knees. One can spend time to make his skin and his or her face look good and then entirely forget about the knees. Part of the reason is that most people are ignorant of the intricacies of the knee joint mechanism.
Now, it has been made clear that the knees are one of the most hardworking parts of the human body, responsible in the areas of propelling the body forward as in walking or in more complicated actions such as long jump or a high-flying dunk in the sport of basketball. Aside from moving forward the knee also helps in quick stops and quick inside turns such as in hockey and soccer. In this scenarios where the knee is pushed to its limits can one find the regularity of sports related injuries.
It is a good thing that science and technology continue to find ways in helping athletes and ordinary citizens alike in taking care of their knees. In the 21st century there are a significant amount of accumulated knowledge that would prevent major injuries. Foremost of these discoveries is the fact that that knees are entirely dependent on ligaments and muscles. Now muscles can be strengthened, an act that requires the participation of the individual. Therefore, strength training and cross-training (especially for athletes) creates a robust knee joint that can withstand repeated abuses.
It is also important not to take knee problems for granted. It has been shown in the preceding discussion that problems like ill fitting shoes or inborn physical defects such as bowleggedness if not treated or corrected will result in bigger problems down the road. It is good to know that knees just like other parts of the body require proper care and that repetitive use should be avoided. In the case of athletes they must have access to a competent physician specializing in orthopedic medicine so that they will always be guided in their exercise regimen and treatment in case of injuries.
Aigner, R. & J. Gillquist. (1991). Arthroscopy of the Knee. New York: Thieme Publishers.
Griffith, H. & D. Friscia. (2004). Complete Guide to Sports Injuries. New York: Berkley Publishing Group, Inc.
Mafuli, N. (2001). Sports Medicine for Specific Ages and Abilities. UK: Harcourt Publishers Limited.
Moore, K. & A.M.R. Agur. (2007) Essential Clinical Anatomy. Baltimore, MD: Lippincott and Williams and Wilkins.
Moore, K. & A. Dalley. (2002). Clinically Oriented Anatomy. Baltimore, MD: Lippincott and Williams and Wilkins.
Siliski, J. (1994). Traumatic Disorder of the Knee.
White, M. (1995). Water Exercise. IL: Human Kinetics.