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Anatomy and Injuries of the Knee John Hardin SPHS Sports Medicine Anatomy-Bones • Bones – Femur • Medial/lateral femoral condyles articulate w/ tibia – Tibia • Tibial plateau is flat-articulates w/ femoral condyles – Fibula • Articulates w/ tibia – Patella • Sesamoid bone protects anterior joint • Enclosed in quadriceps/patellar tendon Anatomy-Joints • Joints – Tibiofemoral • Hinge joint with synovial lining – diarthrodial – Patellofemoral – Superior Tibiofibular Anatomy-Meniscus • Meniscus – Medial and lateral – Fibrocartilaginous disks • Thicker on outside than inside (poor blood supply) – Lie on top of tibial plateau – Increase stability – Make condyles fit better – Shock absorbers Anatomy-Ligaments • ACL-anterior cruciate ligament – Runs from anterior tibia to posterior femur – Prevents anterior displacement of tibia on fixed femur – Prevents femur from moving posterior during weight bearing – Stabilizes tibia against excessive internal rotation Ligaments • PCL-posterior cruciate ligament – Runs from posterior tibia to anterior femur – Prevents posterior translation of tibia on fixed femur – Prevents femur from moving anterior during weight bearing • Both ACL and PCL “cross” or wrap around each other—taut when in extension and looser when in flexion Ligaments • MCL-medial collateral ligament – Attaches on the medial femoral epicondyle & anteromedial tibia – Thickened portion of joint capsule – Two parts-superficial and deep • Deep portion attaches to medial meniscus – Stabilizes against valgus stress applied to lateral aspect of joint capsule Ligaments • LCL-lateral collateral ligament – Attaches to lateral femoral epicondyle and head of fibula – Stabilizes against varus stress when force is applied to medial aspect of joint • Both the MCL and LCL are tightest during full extension of knee and relaxed during flexion Ligaments Muscles • Quadriceps – Rectus femoris, vastus lateralis, vastus medialis, vastus intermedius • Knee extension, hip flexion • Hamstrings – Biceps femoris, semimembranosus, semitendinosus • Knee flexion, hip extension Muscles • Gracilis – Knee flexion, hip adduction • Sartorius – Knee flexion, hip flexion, hip external rotation • Popliteus – Knee flexion • Gastrocnemius – Knee flexion Muscles • Plantaris – Knee flexion • Pes anserine – Goose’s foot – Knee flexion, some internal rotation • Gracilis, sartorius, semitendinosus • Iliotibial Band – Thick band on lateral aspect of thigh • Attaches at Gerdy’s tubercle on the lateral aspect of tibia Preventing knee injuries • Conditioning – Strength, flexibility, cardiovascular and muscular endurance • Hamstring strength 60% of quad strength • Rehabilitation – Strengthen all muscles around knee joint • Shoes – proper type for surface – Length of cleats – Turf vs grass Preventing knee injuries • Knee braces – Functional vs. prophylactic • Functional—used to provide support to an unstable knee • Usually custom fitted to some degree • Uses hinges and supports to control excessive rotational stress and tibial translation • Prophylactic-worn on lateral aspect knee to protect MCL. • Usefulness questioned—does it cause more injuries? ACL rupture • Mxn: – fixed foot and external rotation of femur – knee in valgus position – hyperextension • S/S: – – – – – – – “pop”, knee gives out instability of knee joint swelling within knee joint—hemarthrosis intense pain initially but still able to walk “+” Lachman’s test “+” anterior drawer test MXN MXN • Hyperextension ACL rupture Inside the knee joint • The ACL intact The ACL torn ACL Rupture • Tx: RICE, knee immobilizer, crutches, Physician referral • Requires surgical reconstruction – Timing of surgery decided by athlete, parents, doctor – Grafts used are patellar tendon, hamstring tendon, cadaver graft, allograft – 3-5 weeks in brace, 6-9 months return to activity Stress tests • Lachman’s test Stress tests • Modified Lachman’s Stress tests • Anterior Drawer test PCL Rupture • Mxn: – hyperflexion – falling on bent knee with foot plantar flexed – Hit on fixed anterior tibia • S/S: – “pop” at the back of knee – POT and swelling in popliteal fossa – + posterior sag test, +sunrise test, + posterior drawer test PCL rupture • Tx: – RICE – Immobilization – Crutches – Physician referral – 6-8 weeks rest/rehab – If surgery is elected, 6 weeks immobilization PCL rupture Stress tests • Posterior sag Strest tests • Sunrise or posterior sag MCL Sprain • Mxn: – Blow to the lateral side of knee (valgus stress) – External rotation of tibia Mxn MCL sprain • 2nd degree?? MCL sprain • S/S: • 1st degree – POT over MCL, stable but pain with valgus stress, mild joint effusion, mild joint stiffness, full ROM • 2nd degree – Partial tearing-superficial portion, POT over MCL, some instability with valgus stress but solid endpoint, moderate joint effusion, joint stiffness, limited ROM, unable to fully extend knee joint MCL Sprain • S/S: • 3rd degree – – – – – – Complete tear—superficial and deep portions POT over MCL Moderate to severe effusion Severe pain Loss of motion due to pain, effusion, muscle guarding “+” valgus stress in 0 and 30 degrees, no endpoint Stress tests for MCL • Valgus stress test @ 0 Valgus stress @ 30 MCL Sprain • • • • Tx: RICE Crutches Knee immobilizer/brace – 1st degree 1-2 weeks – 2nd degree 2-4 weeks – 3rd degree 4-6 weeks • Physician referral for 2nd degree or greater Complications • The terrible triad or unhappy triad – Torn ACL – Torn MCL – Torn Medial meniscus LCL sprain • Mxn: – Varus force to medial aspect of knee – internal rotation of tibia • S/S: – – – – – POT over LCL, pain, swelling, loss of motion, “+” varus stress at 30 degrees—solid endpoint with 1st degree, less stability but solid endpoint with 2nd degree, no endpoint with 3rd degree – if “+” varus stress at 0 degrees flexion suspect ACL or PCL injury as well LCL sprain • Tx: – RICE – Crutches – Knee immobilizer – Physician referral with 2nd or 3rd degree Meniscus tear • Medial: more often torn than later due to attachment to MCL • Lateral: doesn’t attach to joint capsule making it more mobile, less prone to injury • Mxn: – Weight bearing with rotational force while extending or flexing the knee Meniscus tear • S/S: – Effusion w/in 48-72 hours – POT over joint line – Loss of motion – “locking” – Giving out – Pain with deep knee flexion--squatting Meniscus tear • Types of meniscus tears Meniscus tears • • • • • Tx: RICE Crutches if necessary Physician referral If knee is “locked” by displaced meniscus, go to ER • Arthroscopic surgery to fix Injuries to the Patella • • • • • Dislocation Subluxation Fracture Chondromalacia Patellar tendonitis Patella Dislocation • Mxn: – Foot planted, deceleration, and cutting in opposite direction from the weight bearing foot – Thigh rotates internally while leg rotates externally – Strong forceful contraction of quads (vastus lateralis) Dislocation • • • • • S/S: loss of motion/function at the knee Pain Swelling Deformity POT over medial aspect of knee joint dislocation dislocation Dislocation • • • • • Tx: immobilize in position you find it Ice ER visit After reduction, immobilize in extension about 4 weeks—use crutches • Strengthen muscles of knee, thigh and hip Patella Subluxation • Mxn: same as for the dislocation • S/S: – same as for the dislocation except there will be no deformity – POT over the medial knee joint – Pain with movement • TX: – RICE – Knee Immobilizer and crutches – Physician referral Patella fracture • Mxn: – direct impact or trauma to patella – Indirect trauma in which a severe pull of the patellar tendon occurs against the femur when the knee if semi-flexed • S/S: – – – – hemorrhage which results in significant swelling pain POT over Patella extreme pain with weight bearing/movement Patella Fracture Another x-ray Patella Fracture • • • • • • Tx: RICE Immobilize Crutches ER Possible surgery depending on type of fracture Chondromalacia • Softening and deterioration of the articular cartilage on the posterior side of the patella Chondro • Mxn: – related to abnormal movement of the patella within the femoral groove as the knee flexes and extends – Lateral tracking patella as quads contract usually associated with weak quads (VMO) or in females a wider pelvis Chondro • S/S: – Pain on the anterior aspect of the knee (behind the patella) while walking, running, ascending or descending stairs, sqatting or sitting with knees flexed for a long period of time – Pain with compression of patella in femoral groove Chondro • Tx: – remove from activities that cause the pain – Strenghtening exercises for the quads, especially the VMO – Knee sleeve with patellar support – Ice, heat – Surgery to smooth the posterior side of patella Patellar tendonitis • Also called “jumper’s knee” • Mxn: – excessive running, jumping or kicking causing extreme tension of the knee extensor muscle complex • S/S: – – – – – Pain at the patellar tendon POT over the distal pole of patella Pain increases with activity Thickening of tendon crepitus Patellar tendonitis • TX: – Rest – Ice – Heat – Ultrasound – Cross-friction massage – NSAIDS – Patellar tendon strap/taping – Modify activity Osgood-Schlatter’s Disease • Condition common in adolescent knee • Mxn: – Repeated pull of patellar tendon at tibial tuberosity apophysis due to excessive running, jumping, kicking, etc. • S/S: – pain and POT at the patellar tendon attachment on tibial tuberosity – Excessive bony formation over tubersity as tendon continues to pull at the apophysis Osgood Schlatter’s • S/S: – usually resolves itself when the athlete reaches 18-19 years of age – Enlarged tibial tuberosity remains • Tx: – – – – – Modify activity Ice Tape/patellar tendon strap Padding Strengthening of quads and hamstrings Iliotibial Band Friction Syndrome • Mxn: – Overuse injury that occurs in runners or cyclists attributed to the malalignment and structural asymmetries of the foot and lower leg – Irritation develops over lateral femoral epicondyle or at the band’s insertion at Gerdy’s tubercle on the lateral side of the tibia ITBS • S/S: – POT over the lateral femoral epicondyle – Swelling – Increased pain with activity especially distance running and starts and stops and change of direction ITBS • • • • • • Tx: Stretching the ITB Ice pack/massage Transverse friction massage ITB Modify activity Correct foot/lower leg malalignment Bursitis • Can be acute, chronic, or recurrent • Numerous bursae involved but most commonly injured are the prepatellar or the deep infrapatellar Bursitis • Mxn: – falling directly on knee – Continuous kneeling – Overuse of patellar tendon Bursitis • S/S: – Localized swelling that is similar to a water balloon and is outside the knee joint – Pain especially with pressure Bursitis Bursitis Bursitis • Tx: – Rest – Ice – Compression – NSAIDS – Padding for protection when returning to activity