Knee Anatomy (1)

Modified hinge joint flexion/ extension, internal/ external

rotation

Two distinct joints tibiofemoral joint Patellofemoral joint

Knee Anatomy (2)Tibiofemoral joint condyles of the femur

very rounded medial condyle is larger than the lateral

condyle Tibial plateaus

flattened, very slightly concave “Screw home mechanism”

required to reach full extension tibia rotates laterally on the femur to

produce a locking of the knee

Knee Anatomy (3)

Patellofemoral joint patella

triangular shaped seasamoid bone: protect the knee joint

femur Patellofemoral groove or trochlear surface

Q angle The angle of pull of quadriceps on the

patella normal is 13 degrees male/ 18 female

Knee Anatomy (4)

Menisci firbrocartilage discs Functions:

1) deepen the tibial plateaus or joint2) absorption and dissipation of force3) congruency of the surface to improve wt distribution4) nourishment and lubrication of joint surfaces

Thicker along the lateral portion

Menisci Cont

Poor blood supply (only outer 1/3 receives direct blood supply) Fig 11-5-C

Medial is C shaped; Lateral is O shaped

The medial is more commonly injured because of its attachment to the MCL ligament & more securely attached to the tibia (which makes it less mobile)

Knee Anatomy (5)4 main ligaments- help stabilize knee jtMedial Collateral (Tibial Collateral) prevents valgus & rotational forces/stresses Attaches to medial femoral epicondyle and

anterior medial tibia

Lateral Collateral (Fibular Collateral) prevents varus struss Attaches to lateral femoral epicondyle and

head of fibula

Knee Anatomy (6) Fig 11-9Anterior Cruciate (ACL) Prevents tibia from moving forward/

femur from going back attaches to lateral femoral condyle/

medial tibia at intercondylar eminence

Posterior Cruciate (PCL) Prevents tibia from moving backward/

femur from going forward attaches to medial femoral condyle/

lateral tibia at intercondylar eminence

Knee Anatomy (7)

Bursa – Fig 11-2 C formed by joint capsule function to reduce friction several:

Suprapatellar: largest in body Prepatellar: between skin and patellar

tendon (housemaids knee) Infrapatellar: below petella (superficial

and deep) Pes anserine bursa- medial proximal

aspect of tibia

Knee Anatomy (8)

Muscles-contribute to jt stability Quadriceps (EXT): Vastus lateralis,

vastus medialis, rectus femoris, vastus intermedius; quads also aid in patella alignment

Hamstrings (Flex): Semitendinosus (IR), Semimembranosus(IR), Biceps Femoris (ER)

Gastroc (Flex), Sartorius(Flex/IR), Gracilis (Flex/IR), & popliteus (Flex)

Knee Anatomy (9)

Blood supply – Fig 11-5 femoral artery to popliteal artery, then

medial superior/inferior genicular, lateral superior/inferior genicular

Nerve Supply Femoral nerve(Ant); Sciatic nerve

(post) to tibial nerve and common peroneal nerve

Prevention of Knee Injuries

Stretching and strengthening of knee (FS 11.1)Protective Knee BracesThree types: prophylactic, functional, and rehabilitative (Fig 11-6)Patellofemoral- Fig 11-7- “Cho-Pat” strap: horseshoe knee sleeve Proper footwear- correct shoe for the correct surface

Treatment of Knee Injuries

Normal acute protocol and NSAIDsProgression of cold to hot treatmentsControl swelling, fit for crutches if necessary,increase ROM and strengthReturn to competition the safest and quickest way possible thru rehab, functional activities, and sports specific activities

MCL Injuries

MOI: valgus stress or lateral forces, internal rotationHOPS Pain and swelling over the medial joint, pn over medial epicondyle or medial tibia, + valgus stress test

Tx hinged knee brace, treat symptoms,

strengthen musculature, rule out meniscus tear with MRI; will heal by itself with conservative treatment; immobilize

LCL Injuries

MOI: Varus stress or medial forces HOPS Pain and swelling over the lateral joint, pn over lateral epicondyle or fibular head, + varus stress test

Tx hinged knee brace, treat symptoms,

strengthen musculature; immobilize; can heal by itself

ACL InjuriesMOI: Sudden deceleration, blow to lateral leg

with the knee bent, foot fixed

HOPS Immediate pain and swelling; hot knee;

Pain “inside the knee”; knee “feels loose”, “something not right”

+ anterior drawer stress test and lachmans

Tx depends on the severity, with 3rd degree

= surgery; treat symptoms; immobilize

PCL Injuries

MOI: Fall on a bent knee; posterior force on tibia,

hyperextension

HOPS Immediate pain and swelling; hot knee; Pain

in the popliteal fossa; knee “falling apart” knee “feels loose”

+ posterior drawer stress test, posterior sag test

Tx depends on the severity, immobilized,

strengthen knee musculature; surgery

Menisci Injuries

MOI: Twisting with foot fixed HOPS Pn over the joint line, catching/locking

or giving out of the knee. Popping or clicking in joint line, swelling after activity with little heat, Pn with or deep squat

Tx strengthen knee musculature, surgery

if sx persist; recovery time depends on type of surgery and tear

Patello Femoral Stress Synd.

Precursor: females, high Q angle, weak VMO, MOI: lateral riding of the patella HOPS dull achy pain in the center of the knee, pn

with compression of the patella

Tx isometric quad contractions,

strengthen/stretch all surrounding musculature , closed chain exercises; knee braces; surgery last option

Chondromalacia

Degenerative condition of the articular cartilage of patellaPrecursor: females, high Q angle, weak VMO, MOI: lateral riding of the patella HOPS pain going down stairs, crepitation under

patella

Tx: knee sleeve, avoid knee bends’ strengthening of VMO; surgery last option

Subluxing/ Dislocating patella

MOI: decelaration with cutting maneuver Other injuries that may occur with sub/dislocating patella: may tear the medial retinaculum and or quad tendon, bruise patella and lateral femoral condyle

HOPS pop, violent collapse of knee, + Pattella

Apprehension test, obvious deformity

Tx: RICE, splint if able refer to a physician

Patellar Tendonitis

“Jumper’s knee”MOI: overuse HOPS Pn over the patellar tendon,

crepitation in tendon, thickening of the tendon, pain after prolonged sitting, pn walking stairs,

Tx Rest, eccentric quad strengthening,

stretch hamstrings, treat symptoms, taping, bracing

IT Band Friction Syndrome

Occurs when the IT band snaps over the lateral femoral condylePrecursor: distance runners, cyclist, large Q angleMOI: overuse HOPS Pn while running up and down hill, point

tender over the lateral femoral condyle

Tx Box 11-3; look at the shoes

Osgood Schlatter Disease

Inflammation or partial avulsion of the tibial apophysis due to traction forces (Fig 11-14)Precursor: adolescent athletes (male 10-15; female 8-13)MOI: overuse; jumping and cutting type sports HOPS Pn over the tibial tuberosity, bony growth of

tibial tuberosity; a knot will form

Tx treat symptoms, padding, complete rest (may be

needed); will usually grow out of condition

SPECIAL TESTS

Range of motion AROM N= 135 flex 0 extension RROM

Flexion with IR/ER- prone Extension - seated

Stress Tests + Laxity; Note Pain Valgus = MCL; p.214 Fig 11-19 Varus = LCL; p.214 Fig 11-19 McMurray’s Click- Menisci

SPECIAL TESTS (2)

Stress Tests Anterior Drawer = ACL; p.214 Fig 11-18a Posterior Drawer = PCL; p.214 Fig 11-18a Lachman’s= ACL; See class demonstration Posterior Sag = PCL; p.214 Fig 11-18b Patellar apprehension = Subluxing Patella;

+ sign is apprehension; p.214 Fig 11-20 Ober’s test = IT band contraction; + knee

doesn’t fall into Adduction; p.215 Fig 11-21

Links

http://www.scoi.com/kneeanat.htmhttp://www.swarminteractive.com/products_licensing.shtmlhttp://www.sportsknee.com/kneeanatomy.htm - Anatomy Review

Links

http://www.arthroscopy.com/sp05018.htm- ACL Surgeryhttp://www.sportsknee.com/acl.htm Step by Step of an ACL Surgeryhttp://www.csuchico.edu/~sbarker/injury/knee/ - Knee Scenario