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The Knee: Anatomy and Injuries. 2 Joints at the Knee Tibiofemoral Joint – formed between tibia and femur A HINGE JOINT Patellofemoral joint – formed.

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Presentation on theme: "The Knee: Anatomy and Injuries. 2 Joints at the Knee Tibiofemoral Joint – formed between tibia and femur A HINGE JOINT Patellofemoral joint – formed."— Presentation transcript:

1 The Knee: Anatomy and Injuries

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3 2 Joints at the Knee Tibiofemoral Joint – formed between tibia and femur A HINGE JOINT Patellofemoral joint – formed between the patella and the femur A GLIDING JOINT

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5 Skeletal Anatomy Femur proximal – head and neck of femur, greater trochanter distal – medial and lateral condyles and epicondyles

6 Patella – largest sesamoid bone in body Tibia – tibial plateau forms knee joint with femur The fibula is not a part of the knee joint

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8 Muscles that move the knee and thigh The Quadriceps – Knee Extension 1. Vastus Medialis 2. Vastus Lateralis 3. Vastus Intermedius 4. Rectus Femoris – 2 joint muscle that also acts as a hip flexor

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11 The Hamstrings- knee flexion 3 muscles: 1. Biceps Femoris 2. Semimembranosus 3. Semitendinosus

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14 The Adductors (Groin) Adduct the thigh 1. Adductor Longus 2. Adductor Magnus 3. Adductor Brevis 4. Gracilis

15 The Sartorius: - flexes, abducts, and laterally rotates thigh - longest muscle in the body, “tailor’s muscle” - Crosses hip and knee joint

16 The Iliotibial Tract (IT Band) - neither a muscle or tendon, but a long, thick band of tissue that inserts into the lateral tibia (Gerdy’s Tubercle)

17 What muscles can you identify?

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19 The Major Knee Ligaments 1. ACL – Anterior Cruciate Ligament prevents anterior motion of tibia 2. PCL – Posterior Cruciate Ligament prevents posterior motion of tibia 3. MCL – Medial Collateral Ligament 4. LCL – Lateral Collateral Ligament

20 ACL and PCL run from femur to tibia and form an X inside the knee

21 The Collateral Ligaments MCL: - Medial Collateral Ligament - Runs from medial femur to medial tibia LCL: - Lateral Collateral Ligament - Runs from lateral femur to head of fibula

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23 The Meniscus A “c”-shaped piece of fibrocartilage located in the knee joint between the femur and attached to the top of the tibia Cartilage = meniscus

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26 Differences between medial and lateral Medial - larger and more C-shaped - more firmly attached to tibia - has attachments to MCL Lateral - smaller and more round or O-shaped - not firmly attached to tibia and LCL

27 Blood Supply to the Meniscus Mostly avascular – little or no blood supply Only the outer 20% has a blood supply * Does not have the ability to heal itself unless there is a small tear in the outer 20%

28 Functions of Meniscus 1. Stability 2. Shock absorption 3. Lubrication and nutrition 4. Allows adequate weight distribution

29 Normal Torn

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31 Total Knee Joint Replacement Surgery to replace a painful damaged or diseased knee joint with an artificial joint (prosthesis) Artificial hip invented – first artificial knee in USA

32 The Knee Surgery Thin layer of bone removed from femur – thin metal replaces it Upper layer of tibia replaced with plastic Back of patella replaced with plastic Parts fastened with “bone cement”

33 Risks of Knee Joint Replacement Blood clots in large veins Infection Stiffness Implant Loosening/Failure - more of a problem in younger patients

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37 Knee Injuries and Conditions

38 Genu Valgum: “knock knees”

39 Genu Varum: “bowlegs”

40 Genu Recurvatum: hyperextension of the knee joint

41 Patellofemoral Disorders Problems with patella – most common cause of knee pain Anatomy: - Patella is a sesamoid bone formed in Quad tendon - Patellofemoral joint – patella and femur - Compression forces –

42 Patellar Tendonitis “Jumper’s Knee” Inflammation and degeneration of the tendon that connects the kneecap (Patella) to the shin bone (Tibia).

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44 Chondromalacia Damage to the cartilage under the kneecap Causes: abnormal patellar tracking Most Common Symptom: Knee pain when walking up and down stairs Prevention: strengthen quads Minimize squats, downhill running, biking with low seat

45 Chondromalacia

46 Patellar Dislocation Involves the patella sliding out of its position on the knee. Caused by direct blow or abnormal twisting of the knee Usually lateral

47 Osgood-Schlatter Disease 1. Painful swelling over tibial tuberosity (patellar tendon insertion) 2. Usually occurs between 9-13 years of age 3. Pain increases with activity

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49 The Chopat Strap

50 Iliotibial Band Friction Syndrome Occurs where IT Band rubs over femur at the knee joint Common in running (esp. downhill) or any activity with repetitive flexion Hills or stairs increase pain Lots of IT Band stretching

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52 Popliteal Cyst “Baker’s Cyst” Fluid accumulation in posterior knee (popliteal space) Patient usually complains of a mass behind the knee

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54 Prepatellar Bursitis “Housemaid’s Knee” Tender swelling over the kneecap (prepatellar bursa)

55 Pes Anserine Bursitis Inflammation of a bursa in your knee. The pes anserine bursa is located on the inner side of the knee just below the knee joint. Tendons of three muscles attach to the shin bone (tibia) over this bursa SGT: Sartorius, Semitendinosis, Gracilis

56 Knee Sprains

57 ACL Sprain >200,000 injuries/year >100,000 reconstructions/year Higher incidence in females Males = contact Females = noncontact pOEdUdoM4

58 ACL Sprain 1. MOI: twisting of knee forced hyperextension lateral blow to knee *foot must be firmly anchored to playing surface 2. 50% of people describe a “pop” in knee 3. Knee fills with blood quickly Hemarthrosis 4. Usually immediate loss of motion 5. Knee feels unstable

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60 Anterior Drawer Test: examiner attempts to slide the tibia forward which may indicate a torn ACL ligament ?v=1iWqUsd1aqY

61 ACL Sprain Who needs surgery? - Activity level? - Level of Competition - Age?

62 ACL Surgery Arthroscopic Graft options Patellar Tendon Semitendinosus Gracilis Cadaver Synthetic

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64 PCL Sprain 1. MOI: excessive hyperextension hyperflexion tibia forced posteriorly (blow to front of knee) “dashboard knee” Possibly 90% of all PCL injuries due to motor vehicle accidents?

65 2. Mild hemarthrosis 3. Posterior knee pain 4. Walk with knee slightly flexed, avoid full extension 5. Posterior sag of tibia 6. Surgery?

66 MCL Sprain MOI: Blow to the outside of the knee = Valgus Force Possible overuse – breaststroke in swimmers Commonly associated with meniscal injuries – attached to medial meniscus No surgery

67 MCL Sprain

68 Valgus Stress Test: tests for injury to the MCL ligament

69 LCL Sprain MOI: Blow to inside of the knee – Varus force Grade III tear may require surgery

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71 Varus Stress Test: tests for injury to the LCL ligament

72 Injuries to the Meniscus 1. MOI: Rotation of the knee as the knee extends during rapid cutting or pivoting

73 2. Signs and Symptoms: - pain - joint line tenderness - catching or locking - knee buckling or giving way - swelling - incomplete flexion - clicking on stair climbing

74 3. Surgery? Meniscectomy: removal of the meniscus - Total meniscectomy = osteoarthritis Depends on location of tear, type of tear, and blood supply

75 Types of Meniscal Tears - bucket handle - Flap tear - Transverse tear - Horn tear

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77 Tests for Meniscal Tears Apley’s Compression

78 “The Unhappy Triad” Tear of the medial meniscus, anterior cruciate ligament (ACL), and medial collateral ligament (MCL)


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