Chapter 20 The knee and related structures Athletic Training Spring 2014 Jihong Park Bones & joints Femur, tibia, fibula, & patella Femur & tibia Weight bearing & muscle attachment Patella functions Anterior protection Decrease stress Leverage for knee extension Tibiofemoral: hinge Has a small amount of rotation Patellofemoral: gliding Meniscus Function Cushion stresses Stabilise knee Deepens articulation Medial Meniscus MCL Joint capsule Lateral Meniscus 2X movable Not connected to joint caps Not connected to LCL Meniscal blood supply Generally poor 3 zones Exterior (outer): best Middle Interior (inner)-avascular, most non existent Cruciate ligaments Collateral ligaments Anterior cruciate ligament (ACL) Prevents Anterior translation of tibia Posterior translation of femur Posterior cruciate ligament (PCL) Prevents Posterior translation of tibia Anterior translation of femur Strongest knee ligament Medial Valgus stress External rotation of tibia Lateral Varus stress Internal rotation of tibia 1
Capsular ligaments Joint capsule Collateral ligaments are thickened capsule Capsule also provides restraint 4 areas Anterio medial Anterio lateral Posterio medial Posterio lateral Quadriceps Rectus Femoris Vastus Lateralis Vastus Intermedius Vastus Medialis Hip flexion & knee extension RF Knee extension only 3 vastus Hamstrings Biceps Femoris Semitendinosis Semimembranosis Hip extension & knee flexion Q:H ratio? Other muscles Muscles & tendons Anterior Quadriceps tendon Patellar tendon Medial Adductors Sartorius Gracilis Lateral Iliotibial Band 2
Severity of injury can be determined by: Q-angle Muscle strength Force of trauma Fixation of foot Previous injuries Playing surface conditions Q-angle Knee alignment Genu valgum (Knock-knees) Genu varum (Bowlegs) Recurvatum ( Hyperextended knees) Line from middle of patella to ASIS Line from tibial tubercle straight through the center of the patella Normal Males 10-13 o Females 13-15 o Pathological >18 o MCL sprain MCL sprain MOIs: Valgus force S/S: Severity dependent (1, 2, 3 ) 1 - pain, no laxity 2 - pain, w/ laxity - has endpoint 3 - pain w/laxity - no endpoint Tx: Out 1 wk-2 months depends on severity of injury Grade 1 RICES Possibly crutches Grade 2 RICES Crutches Possible immobilising Grade 3 RICES Crutches Immobilising splint As long as there is no additional trauma, surgery is not necessary LCL sprain ACL sprain MOIs: Varus force with IR of tibia (most common) Cutting/twisting If severe enough damage can also occur to the cruciate ligaments, ITBand, and meniscus, producing bony fragments as well S/S & management: similar to MCL sprain Most serious knee ligament injury MOIs (non-contact: 80%) knee is valgus and the tibia is externally rotated (most common) Deceleration combined with twisting Push off or landing during jumping with rotation (both IR & ER) Planting the foot and cutting the opposite way Direct blow forcing femur posterior Experience pop w/sever pain and disability Rapid swelling at the joint State knee feels like it is coming apart 3
ACL sprain management ACL INJURY EPIDEMIOLOGY RICE; use of crutches Pre-operative rehab Maintain muscle function and normal ROM Age and activity may factor into surgical option Time out 4 months to 1 year Reconstruction Autograft vs. Allograft Patellar tendon, Semitendinosus, Cadaver NCAA Injury Surveillance System 1989-2002 (Agel 2006) 1989-1993 1994-1998 1999-2002 Men's Basketball 49 / 739,026 =.07 75 / 746,147 =.10 55 / 628,571 =.08 Women's Basketball 189 / 639,898 =.29 194 / 671,388 =.29 169 / 592,982 =.29 Men's Soccer 81 / 626,232 =.13 77 / 640,699 =.12 48 / 505,263 =.10 Women's Soccer 97 / 308,748 =.31 158 / 478,276 =.33 160 / 477,612 =.34 Injury rate expressed per 1,000 exposures Why different? 2-8X greater occurrence in females Knee vs. hip strategy Dynamic valgus Wider hips - Q angle Smaller intercondylar notch Laxity Hormones Landing mechanics * Pictures are from University of Southern California Hip vs. knee Prevention program Agilities Flexibility Strengthening Plyometrics Techniques Mandelbaum 2005 Control: 32/1901 Enrolled: 2/1041 88% reduction in ACL tears 4
PCL sprain Important because it provides a central axis for rotation, but not most serious injury (incidence is small) MOIs Falling on bent knee (most common; may tear ACL too) Direct blow to anterior tibia (posterior translation of the femur) Can also be damaged as a result of a rotational force with hyperextension Extreme IR of Femur or ER of tibia similar as ACL Joint capsule Injuries Rotary Instability Anteriomedial, anteriolateral, etc Anteriolateral most frequent MOIs Sudden deceleration w/ IR of tibia or ER of femur Hyperextension Direct blow forcing femur posterior Push off or landing during jumping with rotation Direct blow with IR of tibia or ER of femur Meniscal injuries Medial meniscus is more commonly injured due to ligament attachments (coronarymcl & joint capsule) and decreased mobility MOIs Rotary force with knee flexed or extended Cutting and twisting while WB Medial meniscus can accompany MCL or ACL Meniscal injuries Pain with joint compression & rotation Joint line pain and loss of motion Portions may become detached causing locking, giving way or catching within the joint : surgery (arthroscopic) Menisectomy or repair Time out: 4 weeks - 3 months Osteochondritis dissecans Partial or complete separation of a piece of articular cartilage and subchondral bone Can occur in other joints (elbow, hip, etc) Medial femoral condyle is most common MOI: Idiopathic May be from blunt trauma Possible skeletal or endocrine abnormalities A prominent tibial spine impinging on the medial femoral condyle Osteochondritis dissecans S/S: Sharp & achy pain Quad atrophy/point tenderness Catching/locking of the joint Rest & immobilisation for children Conservative Tx Long time (10-18mon) Surgery if detached 5
Patellar conditions: subluxation/dislocation MOIs: Deceleration and cut in opposite direction of weight bearing foot, Patellar Malalignment RICE, immobilisation, brace/tape Patellar malalignment Wide hips Genu valgum ( Q angle) Shallow femoral grooves High-riding flat patellae Muscle imbalances Pronation Patellar conditions: Patellofemoral pain syndyrome Etiology Tightness of the hamstrings, gastrocnemius, ITBand Increased Q-angle Foot pronation Imbalance between VL & VM Patellar alta Patellar tendon is longer than the patellar; thus patellar is located higher than normal Lateral patellar tracking Swelling with irritation of synovium crepitus Pain with: prolonged sitting patellofemoral compressive force ascending or descending stairs weakness of the quadriceps Patellar conditions: Patellofemoral pain syndyrome Patellar conditions: chondramalacia Strengthening of the VM and hip abductor (glut medius) Flexibility exercises for the hamstrings, gastroc, and ITBand Orthotics to correct pronation McConnell taping for proper patellar tracking Softening and deterioration of the cartilage on the posterior side (underneath) of the patella MOI: idiopathic Malalignment: Q-angle > 20 Patellar alta A shallow femoral groove Laxity of the quadriceps Pain with walking, running, ascending crepitus Conservative Surgery Patellar conditions: patellar tendon rupture Etiology Forced knee flexion Powerful contraction of quadriceps S/S: Pop, obvious deformity Severe pain Surgery Osgood Schlatter & Larsen-Johansson Disease Common in adolescent athletes, who s tibial tubercle has not ossified (fully developed) Repeated contusion causes a calcium deposit to develop S/S: swelling, pain, tenderness over the tibial tuberosity, gradual degeneration of the apophysis (due to impaired circulation) Modify activities Icing before and after activities 6
Tendon inflammation Quadriceps tendinitis (Kicker s Knee) MOI: repetitive kicking or squatting Patellar tendinitis (Jumper s Knee) MOI: repetitive jumping, running, squatting ITBand tendinitis (Runner s Knee) MOI: genu valgum, pronation, >Q-angle, overuse Pes anserine tendinitis (Cyclist s Knee) MOI: repetitive flexion/ir, genu valgum 7