EDUCATIONAL OBJECTIVES
The learner should, at the completion of the chapter, be able to perform the following:
ANATOMY
The knee is the largest joint in the body. Despite its size, though, it is structurally very weak. The joint's primary weakness is due to its relatively unstable bony structure. To illustrate this instability, consider the femur, or thighbone. The femur is the longest and strongest bone in the body. However, it sits precariously on top of the smaller tibia, which is the main weight-bearing bone of the lower leg. These two bones slide back and forth on each other, even in non-stressful, non-athletic activities. Subtracting further from the joint's stability is the small amount of normal rotation by the femur on the tibia. Not everything in this joint's structure is detrimental to stability. The distal end of the femur has two slightly convex surfaces, called condyles. These condyles articulate with the slightly concave surfaces of the tibia. However, once the knee starts to bend, whether the action is walking, running, or climbing stairs, stability from these convex and concave surfaces is greatly diminished.
The femur and tibia are only two of the four bones of the knee joint. The next largest bone is the fibula, the non-weight-bearing bone of the lower leg. The fibula articulates at the knee only with the tibia, and serves as the attachment for the lateral collateral ligament and biceps femoris muscle. The fourth bone of the knee joint is called the patella, or knee cap. The patella, encased in the powerful patellar tendon, moves up and down in front of the knee in the space between the two condyles of the femur.
The instability of the knee's bony structure is partially compensated for by strong ligaments and potentially even stronger muscle support. Four important ligaments help stabilize the knee: the medial collateral ligament, the lateral collateral ligament, and the anterior and posterior cruciate ligaments.
On the medial side of the knee, the broad, flat medial collateral ligament (MCL) helps secure the femur to the tibia. This ligament also connects to the cartilage of the knee, the medial meniscus. Located on the lateral side of the knee, the lateral collateral ligament (LCL) is not quite as strong as the medial ligament. The LCL is a cord-like ligament that does not attach to the lateral meniscus. The collateral ligaments assist in reducing valgus and varus (abduction and adduction of tibia on femur) movement in the knee joint. The two cruciate ligaments form an "x" in the center of the joint (cruciate comes from the Latin word meaning cross). These ligaments control anterior and posterior movement of the femur on the tibia.
More than any other joint, the knee is dependent on good muscle support. In fact, there are 12 muscles that support the anatomical structures of the knee joint. Most of the support comes from the large muscle groups in the thigh and lower leg. The supporting muscle group on the anterior aspect of the thigh is called the quadriceps. The quadriceps group is comprised of: rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius. The quadriceps muscles, which extend (straighten) the lower leg, converge to form the patellar tendon. This tendon encases the patella and inserts on the front of the tibia on the tibial tubercle. The vastus medialis muscle is vital in patellar tracking.
The muscles located on the posterior aspect of the thigh are called the hamstring and include the semitendinosus, semimembranosus, and biceps femoris. The hamstring muscle group flexes (bends) the knee and also helps control the rotary movements of the tibia. Called a natural knee brace by many athletic trainers, the hamstrings originate on the pelvis and femur and divide to attach below the knee on the tibia and fibula. While the quadriceps and hamstrings are most commonly known, other muscles also provide support and control movement of the knee. These muscles include the sartorius, gracilis, popliteus, gastrocnemius, plantaris, and tensor fascia latae/IT band.
The knee joint contains two tough, fibrous cartilages, known as menisci. They are called the lateral meniscus and medial meniscus. These menisci rest on top of the tibia in its two shallow concave indentations. The menisci form a cushioned base for the medial and lateral condyles of the femur. Other functions of the menisci include shock-absorption, adding to joint stability and helping to smooth the gliding and rotating movements of the femur and tibia.
Other structures in the knee of special concern in athletics are the
bursae, synovial membrane, and fat pads. The bursae are closed, fluid-filled
sacs that serve as cushions against friction over a prominent bone, or
where a tendon moves over a bone. The synovial membrane is a large, closed
sac that lines the inside of the knee joint, helping to lubricate the tendons,
ligaments, and bones. Fat pads are specialized soft tissue structure for
weight bearing and absorbing impact. This area of the body is innervated
by a number of different nerves. The sensory distribution of a nerve root
is called a dermatome, which produces feeling in a certain anatomical area.
The motor distribution of a group of muscles innervated by a single nerve
root is called a mytome and it produces movement of the anatomical structures.
KNEE, QUADRICEPS AND HAMSTRINGS ANATOMY
Bones
Flexion: decreasing angle between the femur and the tibia
Extension: increasing the angle between the femur and the tibia
Tibial Internal Rotation: rotation of the tibia toward the midline
of the body
Tibial External Rotation: rotation of the tibia away from the
midline of the body
Anterior/Posterior Translation: movement of the femur on the
tibia in a forward (anterior) or backward (posterior) movement pattern
Muscles and Function
L2 - inguinal region: upper two thirds of anterior thigh (quadriceps)
and lateral hamstring
L3 - upper two thirds of the anterior thigh (quadriceps) and medial
hamstring
L4 - anteriomedial aspect of lower leg and rear 1/3 of foot
L5 - anteriolateral and posterior aspect of lower leg and dorsum of
foot
S1 - phalanges and plantar aspect of foot
S2 - proximal 1/3 of posterior aspect of lower leg
Myotomes
L2 - Hip Flexion
L3 - Knee Extension
L4 - Dorsiflexion of ankle
L5 - Extensor Halluces Longus - toe extension
S1 - Plantar flexion of ankle or Hamstring Curl, foot eversion, hip
extension
When determining strength of myotomes, provide resistive force..
EVALUATION FORMAT
The first purpose of an evaluation is to determine if a serious injury has occurred. The evaluation format of History, Observation, Palpation and Special Tests are thoroughly covered in Chapter 2 and Chapter 6. Listed below is an abbreviated version of the H.O.P.S. format.
History: Questions should address mechanism of injury, location of pain, sensations experienced, and previous injury.
Observation: Compare the uninjured to the injured lower extremity and look for bleeding, deformity, swelling, discoloration, scars, and other signs of trauma.
Palpation: Using bilateral comparison, palpate neurological, circulatory, and anatomical structures, and assess for potential fractures.
Special Tests: Special tests assess disability to ligament, muscle, tendon, accessory anatomical structures, inflammatory conditions, range of motion, and pain or weakness in affected area. These tests are well beyond the expertise of a student athletic trainer.
ASSESSMENT TESTS
All injured joints should be properly evaluated. The purpose of a thorough evaluation is to enable the allied health professional to properly assess the severity of the injury and to make recommendations regarding treatment and possible return to participation. Listed below is a review of assessment tests utilized by certified athletic trainers. For further information, consult this chapter's references.
Tests for Knee Ligament Stability
Abduction or Valgus Stress: used to evaluate medial joint stability
Adduction or Varus Stress: used to evaluate lateral joint stability
Anterior Drawer: assesses the stability of the anterior cruciate
ligament
Posterior Drawer: assesses the stability of the posterior cruciate
ligament
Lachman's: used to evaluate the integrity of the anterior cruciate
ligament
Pivot Shift: test for anterolateral rotary stability
Tests for Knee Joint Effusion
Knee Joint Test for Minor Effusion: assesses effusion (swelling)
Ballotable Patella: evaluating marked effusion of the knee
Tests for Patellar Stability
Apprehension: evaluates patella stability
Patella Compression: evaluates the integrity of the posterior
aspect of the patella
Tests for Meniscal Stability
McMurray: evaluates the integrity of the menisci
Apley's Compression: evaluates the integrity of the menisci
CONDITIONS THAT INDICATE AN ATHLETE SHOULD BE REFERRED FOR PHYSICIAN EVALUATION
The knee joint, due to its complex joint movements, is injured frequently. When an injury occurs, chances of it medical referral and potential surgery is increased. Coaches and student athletic trainers should not try to determine whether a knee injury is minor or severe. Without advanced medical training, an evaluation is not possible. It is possible for a knee to be severely injured and to exhibit little swelling or pain; therefore, knee injuries call for immediate referral to a physician. In athletics, the most common knee and thigh injuries occur as a result of contusions, sprains, and strains.
Contusion injuries are caused by a direct blow or by falling on the knee. Besides muscular contusions, direct blows or falls can also damage the bursas that protect the bones and other structures of the knee. Since athletes are likely to suffer knee contusions, the basic first aid treatment is protection, rest, ice, compression, elevation and support. To reduce the occurrence of contusion, kneepads should be worn.
Ligament sprains can be caused by multidirectional forces and are compounded when the athlete's foot is stationary (planted). A common knee sprains occurs in football when a player receives a direct force to the lateral side of the knee joint. In this type of injury, the medial ligament is usually stretched and/or torn. The ligaments supporting the knee joint are usually stretched by one of these mechanisms: shearing, torsion, or compression. Torsion injuries occur when the feet are fixed and the body/injured joint is twisted. Shearing occurs when a force is delivered to the opposite side of the joint. Both types of injuries are common. Sports that require cleated shoes pose a greater risk of injury. In fact, the longer the spike is on the cleat, the greater the risk of injury to increased torsion.
A blow severe enough to cause ligament damage will often result in some excessive torsion. Torsion injuries sometimes damage the ligaments, but most often involve the menisci. Other, usually less severe, knee injuries can be caused by muscular weakness or imbalance, overuse, or repetition; poor running mechanics; or improperly fitted shoes. In addition, some athletes are susceptible to certain knee conditions that are related to the growth process.
Whenever the knee joint is evaluated as a sprain, it is usually placed into one of three categories: first degree (mild), second degree (moderate), or third degree (severe).
First degree sprain: One or more of the supporting ligaments
and surrounding tissues are stretched. There is minor discomfort, point
tenderness, and limited or no swelling. There is no abnormal movement in
the joint to indicate lack of stability.
Second degree sprain: A portion of one or more ligaments
is torn. There is pain, swelling, point tenderness, and loss of function
for several minutes or longer. There is slight abnormal movement in the
joint. The athlete may not be able to walk normally and will favor the
injured leg.
Third degree sprain: One or more ligaments have been
completely torn, resulting in joint instability. There is either extreme
pain or little pain (if nerve damage has occurred), loss of function, point
tenderness, and rapid swelling. An accompanying fracture is possible.
Patellar Tendinitis: The patellar tendon originates from the quadriceps muscles. One of the primary movements of the quadriceps is lower leg extension. This movement is part of the jumping process and the forces generated can be great. Excessive stress placed on the patellar tendon can cause inflammation above or below the patella. Pain is reported by the athlete after exercising, in which some swelling may be present. Cold can be utilized to reduce pain and inflammation. The physician may also prescribe rest. As with many knee problems, strong and flexible hamstrings and quadriceps muscles often can prevent or alleviate patellar tendinitis.
Chondromalacia Patellae: Chondromalacia patellae is a painful degenerative condition that results in the irritation and softening of the cartilage on the posterior aspect of the patella. Running, jumping, kneeling, and climbing stairs can elicit the pain. One cause of this condition is muscular weakness or imbalance. This can cause unusual tracking of the the patella as it moves in the femoral groove. Other causes of chondromalacia patellae are related to the individual athlete's body structure. Whether the cause is muscular or structural, strengthening the quadriceps through straight leg raises and limited range of motion resistance exercises can often correct the problem. Other treatments include cold application before and after activity, muscle setting (isometric) strengthening exercises, and use of knee pads to protect the area.
The Female Athlete's Knee: Patellar problems may be more prevalent for women than men, because of the structural difference in pelvic girdle width between males and females. The female's wider pelvis creates a sharper angle where the femur attaches to the pelvis. The Q-angle is formed between the line of resultant force produced by the quadriceps, an imaginary line originating from asis to intersection of an extended line of the patella tendon. A sharper Q angle changes the line of pull of the quadriceps muscles and may cause the patella to be pulled in a lateral direction upon muscle contraction. This change in mechanics can cause chronic conditions such as chondromalacia patellae, patellar dislocation, or subluxation. If a female athlete is suffering from one of these chronic knee injuries, strengthening the medial portion of the quadriceps (vastus medialis) will usually prevent any lateral sliding of the patella. Performing complete range of motion exercises with resistance can strengthen the vastus medialis muscle group. If chronic knee pain persists, refer the athlete to the team physician. Application of cryotherapy and modification of activity or rest are also recommended.
Osgood-Schlatter Condition: This condition is common to adolescent and is characterized by swelling below one or both knees. It involves the growth center of the tibial tubercle to which the patellar tendon attaches. Depending on its severity, the Osgood-Schlatter condition can lead to chronic knee irritation and pain and was first described early in this century as a partial separation of the tibial tubercle from the tendon. Later, it was described as an inflammation of the tibial tubercle, rather than a bone separation. Whatever the cause, this inflammation is aggravated by activity and relieved by rest. Tenderness tends to be most marked at the patellar tendon's insertion point. The athlete will complain of severe pain on jumping, running, or kneeling, and after athletic activity. In cases of long duration, the front of the knee appears enlarged and a bony prominence can be felt. Although Osgood-Schlatter symptoms disappear after adolescence, this bony prominence remains. The athlete's physician may recommend treatment ranging from restriction or modification of sports activity to immobilization in a cast.
Muscular Strains: Since the quadriceps and hamstrings are located in the thigh, muscular strains are common. Common causes of muscle strains are lack of strength, repetitive overuse, improper technique and inadequate warm-up. When palpating the area, the student athletic trainer may note soreness or pain primarily in the soft tissue. Manual resistance to every movement the knee and hip joints can make help reveal the injured muscle. The basic treatment should consist of protection, rest, ice, compression, elevation, and support.
REHABILITATION
Regardless of the mechanism of injury, the student athletic trainer's response to knee injury is basic first aid: protection, rest, ice, compression, elevation, and support, followed by referral to a physician. Muscle strength, power, endurance and balance is necessary to prevent injury. During strength training, the athlete should work to have the strength of the corresponding muscle group of the injured leg equal to that of the uninjured leg. The best way to build this strength is through resistance exercises or weight training. As with all muscles, strength is lost if the muscle is not exercised regularly. It is therefore important that athletes perform strengthening exercises in-season as well as during the off-season. The sports medicine team should recommend a specific knee rehabilitation program, depending on the injury. Before returning to competition, the following rehabilitation guidelines must be met:
Range of Motion Exercises
Flexion
Extension
Tibial Internal Rotation
Tibial External Rotation
Knee
Straight Leg Raises
Quadriceps Tightening (Quad Sets)
Heel Slides
Wall Slides
Step Ups
Leg Curls
Leg Extensions
Quadriceps
Leg Extensions
Straight Leg Raises
Hip Flexion
Hamstrings
Leg Curls
Stationary Bicycle
Hip Extension
Included in any rehabilitation protocol is the following:
The application of preventive and supportive techniques is a time-honored and time-consuming tradition. It is also a very expensive practice. Whether to apply adhesive and/or elastic bandages to an uninjured anatomical structure is a decision the athletic trainer will have to make. All injured joints should be supported initially. An outline of basic taping and wrapping techniques for the knee and thigh follows.
Wrapping Techniques for Compression
KneeWrapping Techniques for Support
The use of protective devices is beneficial if they are properly selected, used in the appropriate setting, correctly fitted, properly applied, and used within the rules and guidelines of the specific sport. Consultation with an equipment specialist and certified athletic trainer is highly encouraged. Listed below are various protective devices that are commercially available to use as an adjunct or replacement to a taping or wrapping procedures.
Listed below are conditions/disorders that affect the knee, quadriceps, and/or hamstrings. Using a medical dictionary, review and define these conditions/disorders.
American Academy of Orthopedic Surgeons (1991) Athletic Training and Sports Medicine (2nd ed.). Park Ridge, IL; American Academy of Orthopedic Surgeons.
Arnheim, D. & Prentice, W. (1997). Principles of Athletic Training (9th ed.). St. Louis: McGraw-Hill.
Anderson M. and Hall S. (1995) Sports Injury Management Baltimore: Williams and Wilkins.
Gallaspy, J. & May D. (1996) Signs and Symptoms of Athletic Injuries St. Louis, Mosby
Harrelson G. & Andrews J. (1993) Physical Rehabilitation of the Injured Athlete Philadeplhia: W.B. Saunders
Hoppenfield, S. (1976) Physical Examination of the Spine and Extremities New York: Appleton, Century, and Crofts.
Mueller W. (1983) The Knee: Form, Function and Ligament Reconstruction. New York: Springer-Verlag.
Norkin & White (1985) Measurement of Joint Motion: A Guide to Goniometry Philadelphia: F.A. Davis Co..
Stone R. & Stone J. (1997) Atlas of Skeletal Muscles (2nd ed.) Dubuque: McGraw Hill.
Thibodeau G. & Patton, K. (1996) Anatomy and Physiology (3rd ed.) St. Louis: Mosby.
Wright K. & Whitehill W. (1996) The Comprehensive Manual of Taping and Wrapping Techniques Gardner: Cramer Products
Suggested Multimedia Resources
Wright, K, Harrelson, G. Fincher L & Floyd, R. (1996) Sports Medicine Evaluation Series: Knee Dubuque, IA: McGraw Hill.
Wright K. & Whitehill W. (1997) Sports Medicine Taping Series: Knee Dubuque, : McGraw Hill.
Chapter 7 - Review Questions
Completion:
1. While the knee is the largest joint in the body; structurally it
is very __________.
2. The main weight bearing bone of he lower leg is the __________.
3. The non-weight bearing bone of the lower leg is the __________.
4. The _______ ligaments assist in reducing valgus and varus (abduction
and adduction of tibia on femur) movement in the knee, while the _______
ligaments control anterior and posterior movement of the femur on the tibia.
5. The four muscles that comprise the quadriceps group are the ______,
_______, ______, and _______.
6. __________ __________ condition is an apophysitis related to the
growth center at the tibial tubercle.
Short Answer:
1. The two cruciate ligaments in the center of the knee form what shape?
2. How does a torsion injury occur to the knee joint?
3. When applying preventive/supportive techniques for the quadriceps
and hamstrings, list the different position that the leg should be placed
in.
4. What are the functions of the menisci?
5. Describe the Osgood-Schlatter condition. Why is it common to adolescents?
6. Are the hamstrings more likely to be contused or strained? Why?
7. Are the quadriceps more likely to be contused or strained? Why?
8. What criteria would be used to determine when the athlete is ready
to return to sports participation?
9. Name the four most important ligaments of the knee.
10. Name the three hamstring muscles.
PICTURES and DESCRIPTION for Chapter 7
Supplies needed: 6" extra long elastic wrap, and 1 1/2" adhesive
tape
Wrapping Procedure:
1. Begin the 6" elastic wrap around the lower leg, spiral around the
leg and knee, and above the knee.
2. Secure the wrap with a small strip of 1 1/2" adhesive tape.
Knee Supportive Wrap
Purpose: To provide support to the knee joint.
General Condition Procedure Used For: Sprains to the knee joint.
Anatomical Structure: Knee joint
Anatomical Position: Knee joint placed in slight flexion
Supplies needed: 4" elastic wrap, and 1-1/2" adhesive tape
Pre-Wrapping Procedure: The athlete should stand with the affected
knee in slight flexion. Instruct the athlete to contract the muscles around
the knee joint.
Wrapping Procedures:
1. Begin the wrap on the lateral/posterior aspect of the lower leg.
Encircle the lower leg, moving medially to laterally.
2. Angle the wrap below the patella and cross the medial joint line.
Cover the thigh’s posterior and lateral aspect. Encircle the thigh, moving
medially to laterally. Angle the wrap downward, staying above the patella,
and crossing the medial joint line. Cross the popliteal space and encircle
the lower leg.
3. Proceed with the wrap, crossing the lateral joint line and angling
above the patella. Encircle the thigh and on the posterior aspect, angle
across the knee’s lateral joint line, staying below the patella. This configuration
should resemble a diamond shape around the patella and cover from mid-thigh
to the gastrocnemius belly.
4. Secure this wrap with 1-1/2" adhesive tape, applied at the wrap’s
loose end.
HAMSTRINGS WRAP
Purpose: To provide support to the hamstring muscle group.
General Condition Procedure Used For: Strains to hamstring muscles.
Anatomical Structure: Posterior aspect of the thigh.
Anatomical Position: In standing position, affected extremity placed
in hip extension.
Supplies needed: 1 1/2" adhesive tape, and 6" elastic wrap
Pre-Wrapping Procedure: The athlete should stand with the affected extremity
placed in hip extension and instruct the athlete to contract the hamstring
muscles.
Wrapping Procedures:
1. Begin the wrap at the thigh’s proximal end. Angle diagonally to the distal aspect of the hamstrings. At this point, begin an upward spiral supportive procedure with the wrap. Overlap each layer by one-half its width, ending at the thigh’s proximal end.
2. Secure the wrap in place by applying an anchor strip of 1-1/2" adhesive tape.
QUADRICEPS WRAP
Purpose: To provide support for the quadriceps muscle group.
General Condition Procedure Used For: Strain and contusions to the
quadriceps muscles.
Anatomical Structure: Thigh.
Anatomical Position: Standing with hip and knee joint slightly flexed.
Supplies Needed: 1-1/2" adhesive tape, and 6" elastic wrap
Pre-Wrapping Procedures: The athlete should contract the quadriceps
muscle group.
Wrapping Procedures:
1. Begin the wrap at the thigh’s proximal end. Angle diagonally to the distal aspect of the quadriceps. At this point, begin an upward spiral supportive procedure with the wrap. Overlap each layer by one-half its width, ending at the thigh’s proximal end.
2. Secure the wrap in place by applying an anchor strip of 1-1/2" adhesive tape.
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