Unit 5: Understanding Athletic-Related Injuries to the Lower Extremity The Knee: Anatomy and Injuries Sports Medicine Mr. Smith

Knee

Mechanics of the Knee Hinge Joint Knee movement Flexion Extension Slight Rotation Gliding Knee stability depends on ligaments, joint capsule, and muscles.

Joint Capsule

Bones of the Knee (Femur) Medial and lateral condyles Medial condyle is longer than the lateral condyle. Trochlea – groove that receives the patella. Articular cartilage

Tibia Tibial plateau Tibial plateau has two shallow concavities (facets) that articulate with the medial and lateral condyles. Tibial tuberosity Main weight bearing bone (95 – 97%).

Tibial Plateau

Patella Largest sesamoid bone in the body. Articulates in the groove between the femoral condyles. Provides a better line of pull for the quadricep muscles.

Patella Tracking

Fibula Lateral collateral ligament and muscle attachment. Non – Weight bearing bone. Located on lateral aspect. Minimal knee function.

Knee Articulations Femur and tibia Femur and patella Tibia and fibula

Ligaments of the Knee

Anterior Cruciate Ligament (ACL) Attachment: femur – intersurface of lateral condyle. Attachment: Tibia – Anterior tibial plateau. Prevents excessive anterior movement and internal rotation of the tibia.

ACL Extension / Tight Flexion / Relaxed Very vascular Usually surgically replaced if torn.

Posterior Cruciate Ligament (PCL) Attachment: Femur -Anterior portion of the lateral surface of the medial condyle. Tibia – Posterior medial tibial plateau. Prevents excessive posterior movement of the tibia on the femur. Prevents hyperextension of the knee

Medial Collateral Ligament (MCL) Attachment: Femur – superior epicondyle. Tibia – Medial aspect / medial meniscus. Resists valgus forces. Resists external rotation of the tibia.

Lateral Collateral Ligament (LCL) Attachment: Femur – lateral epicondyle. Fibula: Fibular head Extracapsular Resists varus forces. Aided by popliteal muscle / IT-band

Meniscus

Meniscus Medial (C- shape) and lateral (O-shape) meniscus. Located on tibial plateau. Primary function – shock absorber. Deepens articular facets Increase surface contact. Helps stabilize knee

Meniscus

Meniscus 3 vascular zones Red – Red Zone- outer 1/3 which has good blood supply. Red – White Zone- middle 1/3 which has minimal blood supply. White – White Zone- inner 1/3 which is avascular (no blood supply)

Bursa's of the Knee Bursa’s are fluid filled sac’s . Reduce friction between anatomical structures. Two dozen bursa’s within the knee. Prepatellar most often injured.

Bursa's of the Knee

Muscles of the Knee

Quadricep Muscle Group

Quadriceps Extensors of the knee. Stabilizers of the knee. Vastus medialis (VMO) – important for patellar tracking. Vastus intermedialis Vastus Lateralis Rectus femoris – Knee extension / Hip flexion.

Patellar Tendon Patellar Tendon – Common tendon for the quadriceps muscle group. Attachment: Tibial tuberosity. Houses the patella.

Hamstring Muscle Group

Hamstrings Flexors of the knee. Extensors of the hip. Prevents anterior tibial movement / Aids ACL.

Other Structures of the Knee

Other Structures Con't Gracilis – Aids in knee flexion. Sartorius – Aids in knee flexion / longest muscle in the body. Gastrocnemius – Aids in knee flexion / primary ankle plantar flexor.

IT - Band Lateral side of knee. Assist LCL in the lateral stability of the knee.

I-T Band Friction

Knee Injuries

Chondromalcia

Meniscus Injuries Mechanism – Compression and rotation femur / tibia. Can be associated with ligament injury (MCL).

Meniscus injuries Signs & Symptoms - Joint effusion (Swelling) - Clicking or locking. - Loss of ROM - Diagnosis is often difficult.

Meniscus MRI

Meniscus Tear

Treatment Surgical treatment - Procedure depends on location and severity of tear. - Resection (Total removal of tear) - Stitch or tack.

Tack Repair

Non Surgical Treatment - Indicated only for minor tears. - RICE (Control Swelling) - Maintain ROM / Strength - Non surgical treatment can result in further damage

Arthriis Arthritis

ACL Injuries Common in sports. Mechanism – External rotation of tibia, knee in valgus position, foot fixed. Signs & Symptoms Feeling pop Knee feels unstable Joint effusion Positive testing

Non Surgical Treatment RICE (Control Swelling) Immobilizer / Crutches Refer to physician Rehabilitation (Strengthening & ROM)

MRI of ACL NORMAL ACL ACL TEAR

Surgical Treatment Arthroscopic surgery Various grafts can be used for repair. Patellar tendon (Autograft) Hamstring (semitendinosus / Gracillis) Cadaver (Allograft) Surgical Treatment

Patellar Tendon (autograft)

Intercondyler Notch

Notch Plasty

PCL Injuries Injured less frequent Mechanism: - Fall on anterior aspect of bent knee with foot plantar flexed. - Hyperextension

PCL MRI

PCL Injuries Signs / Symptoms - Experience “Pop” - Effusion (swelling) - Tenderness posterior aspect of knee - Knee feels unstable - Positive special test

MCL / LCL Injuries MCL injuries are usually caused by a lateral to medial blow to the knee. Also known as a valgus force. LCL injuries are usually caused by medial to lateral blow to the knee. Also known as a varus force.

MCL Injuries Mechanism of Injury - direct blow from the lateral side (Valgus Stress) - severe rotation of the tibia - can be a combination of both

MRI OF MCL TEAR

MCL Sprains 1st degree - ligamentous fibers are stretched - joint is stable during valgus stress test - little or no joint effusion - may be some joint stiffness and medial joint line tenderness - almost full range of motion

MCL Sprains 2nd degree sprain - partial tear of the ligament - slight to moderate laxity during valgus stress test - there is little joint effusion - moderate to severe joint stiffness with loss of ROM

MCL Sprains 3rd degree sprain - Complete tear - severe laxity revealed with valgus stress test - moderate joint effusion - loss of ROM

Treatment of MCL Sprains 1st degree – RICE, Rehab to increase strength, ROM. 2nd degree – RICE, Immobilize, Crutch, 24 hours. Re-evaluate. Refer to physician 3rd degree – RICE, Immobilize, Crutch. Refer to physician

LCL Injuries Not very common in athletics. Occurs by a medial blow to knee which produces a varus stress

Patellar Dislocation

Knee Dislocation

Knee Dislocation

Assessing the Knee Joint

HISTORY What did you feel, hear, …. Was there a pop or snap? Did you get hit by another player? Was your foot planted? Did this happen without being hit? Exactly where does you knee hurt, and be specific? Have you hurt this knee before, when, what was the injury?

HISTORY When did you first notice the condition? Is there swelling or recurrent swelling? What activity hurts the most? Does it ever catch or lock? Do you fell as if the knee is going to give way, or has it already done so? Does it hurt to go up and down stairs?

Observation Does the athlete have a limp, or is it easy to walk? Cant the athlete be full weight bearing? Is the athlete able to perform a half-squat to extension? Cant the athlete do up and down stairs?

Testing for Knee Joint Instability Testing helps one get a better idea of the stability of the joint and an informed decision can be made about playing status. Many tests may point to ligamentous damage, while others will help detect meniscus damage. Knowing these test and how to perform them takes practice and time to understand the degrees of damage done to the knee.

Patellar Apprehension Test for patellar dislocations Positive sign is guarding, and pain.

McMurray Meniscal Test Tests for torn meniscus Positive sign is popping, clicking or pain. Apley’s Compression/Distraction - Tests for torn meniscus - Compression signs same as McMurray - Distraction sign is reduction of pain.

Valgus and Varus Stress Tests Purpose: intended to reveal laxity of the medial and lateral collaterals. The athlete lie supine with the leg extended. Apply stress to the knee either medially or laterally

Valgus Stress Tests The valgus examination in full extension tests the MCL, posteromedial capsule, and the cruciates. The exam at 30 degrees flexion isolates the MCL.

Valgus Stress Test Tests for MCL stability Positive sign indicates an injury to the MCL Test at 0 and 15 degrees

Varus Stress Tests The examiner reverses hand positions and tests the lateral side with a varus force on the fully extended knee and then with 30 degrees of flexion. With the knee extended, the LCL and posterolateral capsule are examined. At 30 degrees of flexion, the LCL is isolated.

Varus Stress Test Tests for LCL stability Positive sign indicates an injury to the LCL Test at 0 and 15 degrees

Anterior Cruciate Ligament Tests Anterior Drawer Test Lachman’s Test

Anterior Drawer Test The tibia’s sliding forward from under the femur is considered a positive anterior drawer sign. If a positive anterior drawer sign occurs, the test should be repeated with the athlete’s leg rotated internally 30 degrees and externally 15 degrees.

Special Tests Anterior Drawer Test - Tests for ACL instability / laxity Positive sign is increase in anterior translation. (No end point)

Anterior Cruciate Ligament Tests Lachman’s Test: is considered to be a better test than the drawer test at 90 degrees of flexion.

Lachman’s Tests The Lachman’s test is administered by positioning the knee in approximately 30 degrees of flexion. One hand of the examiner stabilizes the leg by grasping the distal end of the thigh, and the other hand grasps the proximal aspect of the tibia and attempts to move it anteriorly. A positive Lachman’s test indicated damage to the ACL

Special Tests Lachman Test - Test for ACL instbility/laxity Positive sign is increased anterior tibial translation. (No end point)

Posterior Cruciate Ligament Tests Posterior Drawer Test: is performed with the knee flexed at 90 degrees and the foot in neutral position. Force is exerted in a posterior direction at the proximal tibial plateau. A positive posterior drawer test indicates damage to the posterior cruciate ligament.

Special Tests Posterior Drawer - Test for PCL instability/laxity Positive sign is posterior movement of the tibia.

Posterior Cruciate Ligament Tests Posterior Sag Test: With the athlete supine, both knees are flexed to 9- degrees. Observing laterally on the injured side, the tibia will appear to sag posteriorly when compared to the opposite extremity if the posterior cruciate ligament is damaged.

Special Tests

Prevention of Knee Injuries To avoid injuries to the knee, the athlete must be as highly conditioned as possible, which means total body conditioning that includes strength, flexibility, cardiovascular and muscle endurance, agility, speed and balance. THE MUSCLES around the knee MUST be strong and flexible.

Prevention of Knee Injuries Athletes participating in a particular sport should acquire a strength ratio between the quadriceps and hamstring muscle groups. Fro example: the hamstring muscles of football players should have 60 to 70 percent of the strength of the quadriceps muscles. The gastrocnemius muscle should also be strengthened to help stabilize the knee. Although maximizing muscle strength may prevent some injuries, it fails to prevent rotary-type injuries.

Prevention of Knee Injuries Shoe Type: Cleat Length Astro Turf shoes: more grip=more injuries Sneakers are good for artificial surfaces

Functional and Prophylactic Knee Braces Functional Knee Braces are used to protect grade 1 and 2 sprains of the ACL and MCL, and reconstructed ACL knees. Most of them are bilateral knee braces, meaning there is a hinge on both sides of the brace. These braces have an important part within the athletic community. They will also give the athlete confidence while playing.

Functional and Prophylactic Knee Braces Prophylactic Knee Braces are designed to prevent or reduce the severity of knee injuries. They are worn on the lateral surface of the knee to protect the medial collateral ligament.

Knee Injury Treatments Straight Leg Raises

Knee Injury Treatments Side Leg Raises

Knee Injury Treatments Side Leg Raises

Knee Injury Treatments Terminal Knee Extensions

Knee Injury Treatments Step Ups

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