chapter 10: the knee

Chapter 10:The Knee

Anatomy

• The bones that comprise the knee joint:

• Tibia• Fibula• Femur• Patella

• There are two joints in the knee:

• Tibiofemoral joint• Patellafemoral joint

Anatomy

• The medial and lateral meniscus rest between the femur and tibia.

• They are responsible for shock absorption, improved bony correlation, joint lubrication, improved weight distribution, and decreased friction.

• The patella guides the quadriceps, decreases friction during movement, and protects the femoral condyles.

Anatomy of the Knee• Knee is a hinge joint• Articulation (point of

contact)– Consists of 3 bones

• Stabilized by– Four major ligaments– Cartilage– Strong musculature

• Knee is able to rotate

Cartilage• Ends of the tibia and femur

– Covered/cushioned by• Pieces of tough cartilage tissue• Called menisci

– Help to stabilize the knee joint– Without bones would rub & wear down quickly

• Top of tibia– Flat like a tabletop

• End of femur– Rounded (called condyles)– Without stabilization, femur would move a lot on the

tibia

Cartilage-Menisci• Lateral & Medial

– Thicker on sides– Thinner in the middle– Form a dish-shaped

hollow– Attached to the top of

the tibia– Provide a seat for the

femoral condyles to sit in

– Femur moves but will not roll off

Ligaments• 4 primary knee ligaments

– Medial collateral (MCL)• Helps provide stability to inside of

knee– Lateral collateral (LCL)

• Helps provide stability to outside of knee

– Anterior cruciate ligament (ACL)• Keeps tibia from moving forward on

the femur– Posterior cruciate ligament (PCL)

• Prevents tibia from moving backward on the femur

• ACL & PCL– pass through the middle of the knee

joint– Cross each other (i.e cruciate

means “cross-shaped”)

Ligaments of the Knee

• Anterior cruciate ligament (ACL)

• Posterior cruciate ligament (PCL)

• Medial collateral ligament (MCL)

• Lateral collateral ligament (LCL)

Anatomy• Muscles of the Knee

• Quadriceps muscles• Responsible for knee extension

• Hamstring muscles• Responsible for knee flexion

• Calf muscles• Assist in knee flexion

• Other muscles that act at the knee• Sartorius• Popliteus• Plantaris• Gracilis

Muscles of the Knee• Provide

– Movement– Stability

• Primary muscles spanning the knee– Quadriceps group (perform knee extension)

• Vastus medialis, vastus lateralis, vastus intermedius & rectus femoris

– Hamstring group (perform knee flexion)• Biceps femoris, semimembranosus & semitendinosus• Help prevent forward movement of the tibia on the

femur– By the location of their attachments

Primary Muscles Spanning the Knee

• Quadriceps group– Vastus medialis, vastus

lateralis, vastus intermedius & rectus femoris

– Perform knee extension

Primary Muscles Spanning the Knee

• Hamstring group– Biceps femoris,

semimembranosus & semitendinosus

– Perform knee flexion

– Help prevent forward movement of the tibia on the femur• By the location of

their attachments

Knee Alignment Concerns

• Genu valgum (knock-knees)• Genu varum (bow legs)• Genu recurvatum (hyperextension)• Q-angle

– Greater than 20 increases risk for injury• Leg length discrepancy

Preventing Knee Injuries• Ligament sprains

– Most common injuries seen at the knee– Muscles provide stability to the knee

• Help resist abnormal bony movement• Athletes should develop strength in the muscles

(quads, hams, gastrocnemius/calf, hip abductors & hip adductors)

– Gastrocnemius-heel raises

– Some trainers & athletes use preventative knee braces• Designed to protect medial collateral ligament

– Tearing can result from a blow to the lateral side

Treating Knee Injuries & Conditions

• Knee is exposed to many forces• Makes it vulnerable to injuries

– Especially the ligaments• Tendon & bone injuries also occur• Patella & menisci are subject to

unique types of athletics-related injuries

Ligament Injuries

• Ligament sprains of the knee– Can be

• Mild• Moderate• Severe

Injuries of the Knee

Patellar Fracture

• Signs & Symptoms:• Pain directly over bone • Slight to moderate swelling • Pain, especially in the first 30º of

movement• Treatment:

• Immobilize and refer to a physician for x-rays

• Requires lengthy immobilization during recovery

Patellar Dislocation • Signs & Symptoms:

• Moderate to extreme pain • Moderate swelling • Complete loss of ROM in knee • Obvious deformity laterally

• Treatment:• Refer to physician for reduction• RICE therapy• Progressive strengthening

program

Patella Dislocation• Patella forced to lateral

aspect of the knee• Often occurs when the knee

is bent and forced to twist inward

• Signs & symptoms– Obvious deformity– Athlete is often in distress

• EMS must be called– Unless team physician is

present• only a physician should

reduce a dislocated patella– Complications may result– Posterior aspect of patella

may be injured further

OUCH!!!!!!!!!

Patella-Femoral Stress Syndrome

• Signs & Symptoms: • Pain and tenderness in lateral aspect

of patella • Slight swelling • Crepitus or popping with extension

• Treatment:• RICE therapy• Closed kinetic chain exercises 0-40

Patellar Femoral Syndrome• Fancy name for a set of

symptoms that include pain/discomfort around patella

• Often caused by patellar tracking problems– Knee bends– Patella is grated across the

femur– Causing cartilage on back of

patella to soften or wear away

– Known as chondromalacia

Chondromalacia

• Signs & Symptoms:• Pain underneath the patella • Grinding or popping during motion • Slight chronic swelling

• Special Tests: Clarke’s Sign

• Treatment:• RICE Therapy• Quadriceps strengthening

Patellar Femoral SyndromeChondromalacia

• Characterized by achiness around the patella– Especially with prolonged

sitting in the same position

• Athlete reports a grinding sensation with flexion/extension– Grinding can be felt by

placing hand over knee

Patella Injuries (Chondromalacia)

Osgood-Schlatter’s Disease

• Signs & Symptoms:• Pain at insertion of patella tendon• Tenderness to palpation • Enlarged tibial tuberosity • Pain with jumping or running

• Treatment:• RICE therapy• Decrease activity or cross-train

Osgood-Schlatter Disorder• Irritation at the site of

the patellar tendon attachment– To front of the tibia

• Called tibial turberosity• Repeated stress

causes the patellar tendon to partially pull away from the bone– Called Osgood-

Schlatter’s disorder

Osgood-Schlatter Disorder• Signs & symptoms

– Discomfort of the knee• Swelling• Tenderness• Pain during activity• Possible bump below knee cap (bony growth at the top of the tibia)

– Can remain even after symptoms have disappeared• Care

– Restrict activity until resolved– Stationary bicycling– Use pain as a guide

• Modify activities based on pain level reported by athlete– Ice before & after activity– Special pad made to fit over front of tibia

• Often improves by age 16 or 17 (but known to last into early 20’s)

Patellar Tendinitis • Signs & Symptoms:

• Pain in patella tendon or at inferior pole of patella

• Pain increases with activity • Squeaking noise with motion• Slight swelling

• Treatment:• Modality treatment • Ice or ice massage• Ultrasound

Muscle & Tendon Injuries• Patellar tendinitis

– Overuse disorder• Characterized by quadriceps weakness• Tenderness over the patellar tendon• Minimal swelling

– Condition is also called jumper's knee• Athletes that do lots of jumping often get this condition

(basketball, volleyball)– Early stages

• Athlete typically has pain after activity– Treatment

• Trainer attempts to control inflammation– Apply ice– Modify athlete’s activity level

» Restricting running & jumping– Rehabilitation program

• Address any flexibility problems or weakness of the leg

Patella Tendon Rupture

• Signs & Symptoms: • Extreme pain with an immediate drop

in pain • Significant swelling • Window shade effect• Complete loss of knee extension • Previous history of chronic tendinitis

• Treatment:• Surgical repair is the only treatment

option• 6-8 months minimum recovery

Ruptured Patella Tendon

Knee Dislocation• Signs & Symptoms:

• Immediate pain that may decrease dramatically

• Obvious deformity (usually anteriorly)• Significant swelling• Decreased blood flow and neural

sensation • Treatment:

• Splinted and transported to hospital immediately

• Surgical intervention is often required for neurovascular and ligament repair

Knee Contusion

• Signs & Symptoms: • Pain at affected site • Moderate swelling and discoloration • Loss of ROM • Decreased weight bearing

• Treatment:• RICE therapy

Patella Injuries (Bursitis)

Prepatellar bursitis is the inflammation of a small sac of fluid located in front of the kneecap. This inflammation can cause many problems in the knee.

Causes Bursitis is the

inflammation of a bursa. The prepatellar bursa can become irritated and inflamed in a number of ways.A direct blow or a fall onto the knee can damage the bursa.

Meniscus Contusion

• Signs & Symptoms: • Pain, especially at full extension• Loss of ROM in extension • Slight swelling

• Treatment:• RICE therapy

Meniscus Tears

• Signs & Symptoms: • Pain, especially when moved similarly

to the mechanism of injury• Pain with full extension or flexion • Diffuse swelling in the joint (effusion) • Pain along the line of the joint • Sensation of locking or giving out • Clicking or popping sound with

movement

Meniscal InjuriesMeniscal injuries damage the cushioning tissue between the tibia and the femur, inside the knee joint, on both sides (medial and lateral) of the knee.

Causes They are highly

vulnerable to injury from abrupt rotations of the knee while it is bearing weight, for example, when you turn to hit a tennis ball, rotating your thigh (femur) while leaving your foot stationary.

Types of Meniscal Tears

MRI Torn Medial Meniscus

Arthroscopic Repair

Posterior horn tear with multiple flaps

Meniscus Tears

• Special Tests:• McMurray’s Test• Apley’s Compression Test • Bounce Home Test

• Treatment:• Referral to a physician • Surgery is often required for full

recovery.• RTP depends on surgical option

selected.

ACL Sprain

• Signs & Symptoms: • Pain in the joint • Athlete hears ‘pop’ at time of injury • Sense of looseness in joint, giving

away, or shifting• Swelling that increases rapidly post-

injury

Anterior Cruciate Ligament Injuries• Keeps tibia from moving

forward on the femur• If ligament is injured

– Athlete is often disabled– Complaining of the knee

“giving away”, collapsing & popping

• Most serious of all knee ligament injuries

• Most frequently surgically reconstructed

Anterior Cruciate Ligament Injuries• Often injured as the

athlete is attempting to change directions quickly– Twists the lower leg– May hear a popping

sound during the twisting• Also injured during

excessive hyperextension

Anterior Cruciate Ligament Injuries• Signs & symptoms

– Rapid swelling– Loss of knee function

• Immediate treatment– PRICE– Knee immobilizer– Crutches

• Follow up with an orthopedist is necessary

• Athlete rarely can continue a high level of function with a torn ACL

Anterior Cruciate Ligament Injuries

• Often needs to be surgically reconstructed– Determination that must be

made by the athlete, surgeon & athlete’s family

– Depends on the amount of instability that exists

– Level of function desired by the athlete

– Age of the athlete

Anterior Cruciate Ligament InjuriesKnee Arthroscopy

Anterior Cruciate Ligament InjuriesKnee Arthroscopy

ACL has poor healing potentialPCL has intermediate healing potentialMCL heals on its own

Bone Tendon Bone

Patella Tendon Graft

Anterior Cruciate Ligament InjuriesRehabilitation

• Focuses on strengthening the hamstrings– Helps stabilize the tibia– Helps regain full function– Even with aggressive ACL rehab

• May be six months before athlete can return to participation

ACL Sprain, cont.• Special Tests:

• Anterior Drawer Test• Lachman’s Test• Pivot Shift Test

• Treatment:• Grade 1 or 2 may be treated conservatively.• Grade 3 tear will require surgery.

PCL Sprain • Signs & Symptoms:

• Pain in posterior aspect of knee • Slight swelling • Joint laxity • Loose feeling with walking

• Special Tests:• Posterior Sag Test• Posterior Drawer Test

• Treatment:• Grade 1 or 2 may be treated

conservatively• Grade 3 tear will require surgery

Posterior Cruciate Ligament Injuries

• Prevents posterior tibial movement on the femur

• Frequently injured when– athlete falls and a bent

knee bears full weight– Knee is forcefully

hyperflexed– Blow delivered to the

front of the tibia

Posterior Cruciate Ligament Injuries• Assessment

– Trainer determines mechanism of injury– Athlete reports having heard a pop– Often little swelling with PCL injury

• Initial treatment– PRICE– Referral to a physician

Posterior Cruciate Ligament Injuries

• Physicians disagree about whether or not surgery should be performed on a severe PCL injury– Even complete PCL tears can be rehabilitated without

surgery• Rehabilitation programs for mild/moderate PCL

sprains– Focus on strengthening the quadriceps– Regaining full function

• Many athletes can become functional again– After initial pain & swelling are controlled– After knee is strengthened

MCL Sprain

• Signs & Symptoms: • Pain increasing with severity • Joint stiffness • Slight to moderate swelling • Decreased ROM • Joint laxity medially

Medial CollateralLigament Sprains

• Frequently injured when an athlete receives a blow to the outside of the knee– Causes knee to bend inward

(valgus stress)– Stresses the MCL

• Mild sprain– Medial joint line pain– Little if any swelling– No joint laxity when stressed

by trainer during assessment– Full knee flexion & extension

Medial Collateral Ligament Sprains• Moderate MCL sprain

– Mild swelling– Discomfort– Some joint laxity when

stressed by the trainer during assessment

• Severe MCL injury– Moderate or severe amount

of swelling– Loss of function– Great deal of joint laxity

when stressed by the trainer during assessment

Medial Collateral Ligament Sprains• Treated with PRICE• Mild injury

– Elastic wrap for compression/support

• Moderate/severe injury– Knee put in an immobilizer– Trainer should consider

possibility of damage to the menisci or an ACL injury

• Rehabilitation– Focuses on strengthening

the muscles that cross the medial aspect of the knee

MCL Sprain, Cont.

• Special Tests:• Valgus Stress Test• Apley’s Distraction Test

• Treatment:• RICE Therapy• Immobilization• Progressive strengthening program

LCL Sprain

• Signs & Symptoms:• Pain over lateral aspect of knee • Slight to moderate swelling • Joint laxity laterally • Joint stiffness • Decreased ROM

Lateral Collateral Ligament Injuries• Occur less frequently than MCL

injuries• Signs & symptoms are similar to MCL

– Except discomfort is at the lateral aspect of the knee

• Treatment– Same as MCL

• Rehabilitation (regaining joint stability)– Strengthening exercises focus on the

lateral thigh muscles & hamstrings

LCL Sprain, cont.

• Special Tests:• Varus Stress Test• Apley’s Distraction Test

• Treatment:• RICE Therapy• Immobilization• Progressive strengthening program

Discussion Questions

• What would be your response to an athlete who wants to play with an ACL tear?

• How would you react on the field if an athlete dislocated their knee?