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