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The Knee Chapter 18 Knee Bony Anatomy • Femur • Condyles – Lateral – Medial • Tibia • Tibial Plateau • Fibula • Patella – Largest sesamoid in body Knee Bony Anatomy Patellofemoral Joint • Point where patella and femur are connected in the trochlear grove Tibiofemoral Joint • • • • • • Tibia meets with femur Weight-bearing joint Hinge joint Joint capsule 4 ligaments Motions: – Flexion – Extension – Rotation of tibia on femur Patella Malalignment Deviations Genu Valgum Genu Varum Knee Cartilage & Menisci • Articular cartilage – Thin layer of connective tissue over ends of long bones • Lateral & Medial meniscus – Shock absorption – Distribute forces – Improve stability of femur as it rides on tibia • Synovial membrane • Synovial fluid – Lubricates articulating surfaces of joints – Supplies nutrients to articular cartilage Knee Cartilage & Menisci Menisci • Two—medial & lateral • Fibrocartilaginous disks • Act as cushions between ends of femur and tibia/fibula – Top of tibia flat – Condyles of femur rounded • Make knee joint more stable Menisci • Medial meniscus – C-shaped – Attached to ligaments on back and medial side of knee – Thus does not move freely – And torn more often than lateral • Lateral meniscus – O-shaped – Attached only at back of knee – Moves more freely as knee flex/extend Ligaments of the Knee • Medial Collateral Ligament (MCL) • Lateral Collateral Ligament (LCL) • Anterior Cruciate Ligament (ACL) • Posterior Cruciate Ligament (PCL) Ligament MCL LCL ACL PCL Attachments Function Muscles of the Knee • Quadriceps – Vastus medialis – Vastus intermedius – Vastus lateralis – Rectus femoris • Hamstrings – Biceps femoris – Semitendinosus – Semimembranosus Quadriceps • Rectus Femoris – Extend knee – Flex hip • Vastus Lateralis • Vastus Medialis • Vastus Intermedius – Extend knee Hamstrings • Biceps Femoris – Flex knee – Lateral rotate knee – Extend hip • Semitendinosus – Flex knee – Medial rotate knee – Extend hip • Semimembranosus – Flex knee – Medial rotate knee – Extend hip Hamstrings Hamstrings Popliteal space Muscles of the Knee • Patellar tendon • Sartorius – Flex hip – ER hip – Flex knee • Gracilis – Adduct hip – Flex knee • Pes Ansurine Patellar Tendon Gracilis Sartorius Label the Muscles of the Knee Common Knee Injuries Patellofemoral Problems Signs & Symptoms • c/o aching pain in front of knee • Gradual onset • Pain behind kneecap • c/o knee giving way • Pain going up stairs • Crepitus • Pain can increase after prolonged knee flexion Patellofemoral Problems Causes • Femur internally rotated • Squinting patella • Excessive foot pronation • Lowering of the arch • Thigh hip internal rotators • Weak hip external rotators Treatment • Orthotics • Muscle strengthening • Muscle stretching • Patellar tracking taping Patellar Tendonitis • aka Jumper’s knee • Inflammation of the patellar tendon Signs & Symptoms • Anterior knee pain • Local tenderness • Local swelling Treatment • Modify activity – Non-impact activities • Stretching quads • Ice • Specialized bracing & taping Fat Pad Syndrome • Inflammation of infrapatellar fat pad – Fatty tissue lying deep under patellar tendon – Hoffa’s fat pad • Often confused with patellar tendonitis Signs & Symptoms • Pain just below patella • Movement of knee aggravates symptoms • Knee tender to palpation • Swelling in anterior portion of knee Fat Pad Syndrome—Treatment • Strengthening exercises • Avoid full knee extension – Leg press • Specialized taping • Ice • NSAIDs Fat Pad Syndrome—Special Test • Pressure applied to proximal patellar tendon with quadriceps contracted – Stressing only the tendon and not the fat pad • Pressure applied over proximal patellar tendon with relaxed tendon – Allow compression of the fat pad MCL Sprain MOI • Valgus force on medial tibiofemoral joint • Blow to lateral aspect of knee • High-energy twisting maneuver Signs & Symptoms • Pain & tenderness on medial aspect of knee – Joint line – Bony attachment sites • Limited motion in full flexion and extension • Swelling • Varying degrees of laxity MCL Sprain—Treatment • PRICE – P: ace, brace, or crutches • Rehab – Submax strengthening in subacute stage, but only if painfree – Bike once gain flex 110-115 degrees • Gentle active & passive stretching • Avoid valgus & twisting forces LCL Sprain • Not frequently involved in sports injuries • MOI: varus stress on lateral tibiofemoral joint • Signs/symptoms & treatment similar to those of MCL sprain MCL/LCL Sprain—Grade 1 • Mild tenderness over ligament • Usually no swelling • Pain felt with valgus/varus test but no laxity MCL/LCL Sprain—Grade 2 • Significant tenderness over ligament • Some swelling seen over ligament • Pain and laxity in joint with stress test, but definite end point MCL/LCL Sprain—Grade 3 • Complete tear of ligament • Pain can vary – Sometimes not as bad as Grade 2 • When knee stressed, definite joint laxity • Athlete may c/o knee wobbly or unstable ACL Injuries • Females who participate in soccer and basketball 4-6 times more likely than males who play same sport • 70% are non-contact injuries • Why incidences higher in females? Female Factors & ACL 1. Biomechanical factors – Use quads more than hamstrings – Land on flat foot vs toes 2. Hormonal influences – Estrogen levels 3. Environmental factors 4. Anatomic risk factors ACL Tear • Contact or non-contact • Low to lateral knee • Knee joint in combined position of flexion, valgus, and rotation of tibia on femur • Once stretched or ruptured, will not heal • Often accompanied by meniscus tears and/or MCL sprains ACL Tear—Signs/Symptoms • • • • Heard or felt “pop” Rapid effusion Knee “buckles” or “gives way” Special testing—Lachman’s or Anterior Drawer – Test’s ligaments integrity – Within first 5 min to avoid protective muscle guarding – Often false-negative testing • F/u with orthopedist – MRI to confirm Lachman’s Test ACL Tear—Treatment • Acute: splint, ice, compressive wrap, crutches • Reconstructive surgery necessary to replace ACL – Patellar tendon – Hamstring tendon (Gold standard) – Cadaver • Comprehensive rehab (6 months) PCL Injuries • Account for 3-20% of all injuries • Less researched because injured less often (compared to ACL) • MOI: tibia strikes ground/object and is pushed backward – Motor vehicle accident – Industrial accident – Fall on flexed knee with foot plantar flexed – Hyperflexion of knee PCL Signs & Symptoms Treatment • Positive Posterior Drawer • Positive Godfrey’s (Sag) Test • PRICE • Rehab – Athlete in supine position, knee bent at 90⁰ – Strength • Quadriceps – Proprioception • Surgery usually avoided Meniscus Tears • Knee twisted suddenly – One or both menisci become trapped between femur and tibia • Ligaments in & around knee torn • As ages, menisci lose their rubbery consistencywill soften and fray – Weakened structures torn more easily Meniscus Tears Meniscus Tears Signs & Symptoms Treatment • Mild knee swelling over several hours or more • Pain • Popping • Locking • Giving way of knee • Ice • Compressive wrap/knee support • Crutches prn • Rehab (non-surgical) – – – – – Streength ROM Activity modification NSAIDS Support sleeve • Surgery – MRI Meniscus Tears—Special Tests • McMurray’s • Apley’s Compression & Distraction • Bounce Home Epiphyseal (Growth Plate) Injuries Epiphyseal (Growth Plate) Injuries Osgood-Schlatter • Group of symptoms involving the tibial tubercle epiphysis • Tibial tubercle: small bump on tibia where patellar tendon attaches • Condition result of traction – Femur growing faster than quadriceps muscle – Result: quad will exert undue pressure on growth center of tibia (at tubercle) • Most likely affect males 1216 yo and females 10-14 yo Osgood-Schlatter Osgood-Schlatter—Signs & Symptoms • Pain over tibial tubercle • Swelling over tibial tubercle • Weakness in quad muscles • Increased pain & swelling with activity • Visible lump • Point tenderness over affected area Osgood-Schlatter—Treatment • Address pain, swelling, flexibility • During practice/competitionwear protective padding – Volleyball knee pad – Combine with neoprene sleeve • After activityice (even if not painful) & NSAIDs • Hamstring tightness cause quads to pull harder during athletic activity – Avoid quad stretching (or try gentle stretch) • Limit or restrict activity (decrease intensity) Osgood-Schlatter—Rehab • AVOID: – – – – Knee extension Heavy squats Power cleans Plyometrics • Maintain aerobic fitness – Cycling – Slide board – Swimming • Exercises to minimize strength loss rather than increase strength – – – – SLR Body weight squats Hamstring curls Calf raises Iliotibial Band Syndrome • Irritation usually at femoral lateral epicondyle • Bursa facilitate smooth gliding motion of ITB, when inflamed ITB not glide easily • Pain worsens with continued movement Iliotibial Band Syndrome • Sudden increase in activity level – i.e. runners who increase mileage • Mechanical problems: – Over-pronate – Leg-length discrepancies – Bowlegged Iliotibial Band Syndrome • Treatment – – – – – – Gait analysis Review training program Proper footwear Ice Stretch Modify training program • Reduce activity level • Cross-train • Special Test – Ober’s Fractures • High-energy trauma • Rare in athletes • Fx to patella result of direct impact to anterior knee • Distal femoral & proximal tibial fxs occur from violent twisting injuries – Fall from height (pole vaulter who misses landing pit) Patella Dislocation • MOI – Plants foot, decelerates, IR thigh • Signs/Symptoms – Obvious deformity – Pain – Swelling – Loss of function Patella Dislocation • Management – Gently extend – Immobolize – Rule out: osteochondral fx • Patella apprehension test Bursitis Rehab • Wall squat • Step-up • Resisted terminal knee extension