Chapter 20: The Knee and Related Structures Jennifer Doherty-Restrepo, MS, LAT, ATC Academic Program Director, Entry-Level ATEP Florida International University Acute Care and Injury Prevention

Functional Anatomy Movement of the knee requires flexion, extension, rotation and the arthrokinematic motions of rolling and gliding Rotational component involves the “screw home mechanism” As the knee extends it externally rotates because the medial femoral condyle is larger than the lateral Provides increased stability to the knee

Taut during full extension and relaxed with flexion Capsular ligaments Taut during full extension and relaxed with flexion Allows rotation to occur Deeper capsular ligaments remain taut to keep rotation in check PCL prevents excessive internal rotation, guides the knee in flexion, and acts as drag during initial glide phase of flexion ACL stops excessive internal rotation, stabilizes the knee in full extension, and prevents hyperextension

Aids knee during extension, providing a mechanical advantage Patella Aids knee during extension, providing a mechanical advantage Distributes compressive stress on the femur by increasing contact between patellar tendon and femur Protects patellar tendon against friction When moving from extension to flexion the patella glides laterally and further into trochlear groove

Kinetic Chain Directly affected by motions and forces occurring at the foot, ankle, lower leg, thigh, hip, pelvis, and spine With the kinetic chain, forces must be absorbed and distributed If body is unable to manage the imposed forces, breakdown in the kinetic chain occurs Knee is very susceptible to injury resulting from the absorption of forces

Assessment of the Knee Joint Determine MOI - This is critical!!! History: Acute Injury Past history Position of body at time of injury? Did the knee collapse? Did you hear or feel anything? Could you move your knee immediately after injury or was it locked? Did swelling occur? Where was the pain

History: Recurrent or Chronic Injury What is your major complaint? When did you first notice the condition? Is there recurrent swelling? Does the knee lock or catch? Is there severe pain? Grinding or grating? Does it ever feel like giving way? What does it feel like when ascending and descending stairs? What past treatment have you undergone?

Walking, half squatting, going up and down stairs Swelling, ecchymosis Observation Walking, half squatting, going up and down stairs Swelling, ecchymosis Leg alignment Genu valgum and genu varum Hyperextension and hyperflexion Patella alta and baja Patella rotated inward or outward Tibial torsion, femoral anteversion and retroversion

Femoral Anteversion and Retroversion Tibial torsion An angle that measures less than 15 degrees is an indication of tibial torsion Femoral Anteversion and Retroversion Total rotation of the hip equals ~100 degrees If the hip rotates >70 degrees internally, anteversion of the hip may exist

Knee Symmetry or Asymmetry Observation cont. Knee Symmetry or Asymmetry Do the knees look symmetrical? Is there obvious swelling? Atrophy? Leg Length Discrepancy Anatomical or functional Anatomical differences can potentially cause problems in all weight bearing joints Functional differences can be caused by pelvic rotations or mal-alignment of the spine

Palpation - Bony Medial tibial plateau Medial femoral condyle Adductor tubercle Gerdy’s tubercle Lateral tibial plateau Lateral femoral condyle Lateral epicondyle Head of fibula Tibial tuberosity Superior and inferior patella borders (base and apex) Around the periphery of the knee relaxed, in full flexion and extension

Palpation - Soft Tissue Vastus medialis Vastus lateralis Vastus intermedius Rectus femoris Quadriceps and patellar tendon Sartorius Medial patellar plica Anterior joint capsule Iliotibial Band Arcuate complex Medial and lateral collateral ligaments Pes anserine Medial/lateral joint capsule Semitendinosus Semimembranosus Gastrocnemius Popliteus Biceps Femoris

Palpation - Swelling Intracapsular swelling Extracapsular swelling May be referred to as joint effusion Swelling within the joint that is caused by synovial fluid and blood is called hemarthrosis Sweep maneuver – sign of joint effusion Ballotable patella - sign of joint effusion Extracapsular swelling Localized over the injured structure May ultimately migrate down to foot and ankle

Special Tests: Knee Instability Valgus Stress Test Used to assess the integrity of MCL Testing at 0 degrees incorporates capsular testing Testing at 30 degrees of flexion isolates the ligaments

Special Tests: Knee Instability Varus Stress Test Used to assess the integrity of LCL Testing at 0 degrees incorporates capsular testing Testing at 30 degrees of flexion isolates the ligaments

Special Tests: Knee Instability Anterior Cruciate Ligament Tests Drawer test at 90 degrees of flexion Tibia sliding forward from under the femur is considered a positive sign Should be performed with knee internally and externally rotated to test integrity of joint capsule

Special Tests: Knee Instability Anterior Cruciate Ligament Tests Lachman Drawer Test Avoids painful flexion immediately after injury Reduces hamstring involvement At 30 degrees of flexion an attempt is made to translate the tibia anteriorly on the femur A positive test indicates damage to the ACL

Variations for the Lachman Drawer Test May be necessary if athlete is large or examiner’s hands are small Variations include: Rolled towel under the femur Leg off the table with athlete supine Athlete prone on table with knee and lower leg just off table

Special Tests: Knee Instability Pivot Shift Test Used to determine anterolateral rotary instability Position starts with knee extended and leg internally rotated The thigh and knee are then flexed with a valgus stress applied to the knee Reduction of the tibial plateau (producing a clunk) is a positive sign

Special Tests: Knee Instability Jerk Test Reverses direction of the pivot shift Moves from position of flexion to extension Without an ACL the tibia will sublux at 20 degrees of flexion

Special Tests: Knee Instability Flexion-Rotation Drawer Test Knee is taken from a position of 15 degrees of flexion Tibia is subluxed anteriorly with femur externally rotated Knee is moved into 30 degrees of flexion where tibia rotates posteriorly and femur internally rotates

Special Tests: Knee Instability Posterior Cruciate Ligament Tests Posterior Drawer Test Knee is flexed at 90 degrees and a posterior force is applied to determine translation of the tibia posteriorly Positive sign indicates a PCL deficient knee

Special Tests: Knee Instability Posterior Cruciate Ligament Tests External Rotation Recurvatum Test With the athlete supine, the leg is lifted by the great toe If the tibia externally rotates and slides posteriorly there may be a PCL injury and damage to the posterolateral corner of the capsule

Special Tests: Knee Instability Posterior Sag Test (Godfrey’s test) Athlete is supine with both knees flexed to 90 degrees Lateral observation is required to determine extent of posterior sag while comparing bilaterally

Instrument Assessment of the Cruciate Ligaments A number of devices are available to quantify AP displacement of the knee KT-2000 arthrometer Stryker knee laxity tester Genucom Test can be taken pre & post-operatively and throughout rehabilitation

Special Tests: Meniscal Tests McMurray’s Meniscal Test Used to determine displaced meniscal tear Leg is moved into flexion and extension while knee is internally and externally rotated in conjunction with valgus and varus stresses A positive test is found when clicking and popping are felt

Special Tests: Meniscal Tests Apley’s Compression Test Hard downward pressure is applied with rotation of the tibia Pain indicates a meniscal injury

Special Tests: Meniscal Tests Apley’s Distraction Test Traction is applied with rotation of the tibia Pain will occur if there is damage to the capsule or ligaments No pain will occur if there is a meniscal injury

Other Special Tests Girth Measurements Subjective Ratings Changes in girth may result due to atrophy, swelling, and conditioning Circumferential measures to determine deficits and gains during rehabilitation Subjective Ratings Used to determine patient’s perception of pain, stability, and functional performance

Other Special Tests Functional Examination Assess walking, running, turning, cutting, etc Co-contraction test, vertical jump, single leg hop tests, and the duck walk Resistive strength testing

Other Special Tests The Q - Angle The A - Angle Line which bisect the patella relative to the ASIS and the tibial tubercle Normal angle is 10° for males and 15 ° for females Elevated angles often lead to pathological conditions associated with improper patella tracking The A - Angle Patellar orientation relative to the tibial tubercle Quantitative measure of the patellar realignment after rehabilitation An angle greater than 35° is often correlated associated with patellofemoral pathomechanics

Special Tests: Patella Patella Grinding Test Determines integrity of patellar cartilage on the undersurface of patella Patella Compression Test Apprehension Tests Patella pushed laterally to determine presence of subluxation/dislocation

Recognition and Management of Specific Injuries

Medial Collateral Ligament Sprain MOI = severe blow or outward twist Grade I: Signs and Symptoms Little fiber tearing or stretching Stable valgus test Little or no joint effusion Some joint stiffness and point tenderness on lateral aspect of the knee Relatively normal ROM

Grade I: Management RICE for 24 hours Crutches if necessary Rehab Cryokinetics Isometrics Progress to SLRs, bicycle riding, and isokinetics Return to play when all areas have returned to normal May require 3 weeks to recover

Grade II: Signs and Symptoms Complete tear of deep capsular ligament and partial tear of MCL No gross instability; laxity at 5-15 degrees of flexion Slight swelling Moderate to severe joint tightness Decreased ROM Pain along medial aspect of knee

Grade II: Management RICE for 48-72 hours Crutch use until acute inflammation phase has resolved Possibly a brace or casting prior to the initiation of ROM activities Modalities 2-3 times daily for pain Gradual progression from isometrics (quad exercises) to CKC exercises; functional progression activities

Grade III: Signs and Symptoms Complete tear of supporting ligaments Complete loss of medial stability Minimum to moderate swelling Immediate pain followed by ache Loss of motion due to effusion and hamstring guarding Positive valgus stress test

Grade III: Management RICE Conservative non-operative versus surgical approach Limited immobilization (with a brace) Progressive weight bearing and increased ROM over 4-6 week period Rehab would be similar to Grade I & II injuries

Lateral Collateral Ligament Sprain MOI = Varus force usually with the tibia internally rotated Direct blow is rare MOI If severe enough damage may also occur to Cruciate ligaments ITB Meniscus Bony fragments may result as well

Signs and Symptoms Management Pain and tenderness over LCL Swelling and effusion around the LCL Joint laxity with varus testing May cause irritation of the peroneal nerve Management Same as MCL injury management

Anterior Cruciate Ligament Sprain MOI = tibia externally rotated with a valgus force Occasionally the result of hyperextension resulting from a direct blow Research is quite extensive in regards to impact of femoral notch, ACL size and laxity, mal-alignments (Q-angle), and faulty biomechanics Extrinsic factors may include, conditioning, skill acquisition, playing style, equipment, preparation time May also involve damage to other structures including meniscus, capsule, and MCL

Signs and Symptoms Management Experience pop with severe pain and disability Positive anterior drawer and Lachman’s Rapid swelling at the joint line Other ACL tests may also be positive Management RICE; use of crutches Arthroscopy may be necessary to determine extent of injury Surgical repair Without surgery, joint degeneration may result Surgery may involve joint reconstruction with grafts (tendon), transplantation of external structures Also requires 4-6 months of rehab

Posterior Cruciate Ligament Sprain MOI = fall on bent knee (most common) Most at risk during 90 degrees of flexion Injury may result due to a rotational force Signs and Symptoms Feel a pop in the back of the knee Tenderness and relatively little swelling in the popliteal fossa Laxity with posterior sag test

Management RICE Non-operative rehab Post-operative rehab Appropriate for grade I and II injuries Focus on quad strengthening Post-operative rehab Surgery will require 6 weeks of immobilization in extension Full weight bearing on crutches ROM after 6 weeks PRE at 4 months

Meniscal Lesions Most common MOI is rotary force with knee flexed or extended Tears may be longitudinal, oblique, or transverse Medial meniscus is more commonly injured due to ligamentous attachments and decreased mobility Also more prone to disruption through torsional and valgus forces

Signs and Symptoms Effusion developing over 48-72 hours Pain in joint line Loss of motion Intermittent locking and giving way Pain with squatting Portions of meniscus may become detached causing locking, giving way, or catching within the joint If chronic injury, recurrent swelling or muscle atrophy may occur

Management No locking but indications of a tear are present Further diagnostic testing may be required If locking occurs, anesthesia may be necessary to unlock the joint Possible arthroscopic surgery Healing dependent on location of tear Menisectomy Partial weight bearing, quick return to activity Repaired meniscus Requires immobilization, gradual return to activity over the course of 12 weeks

Knee Plica MOI = irritation of the plica Signs and Symptoms Management Often associated with chondromalacia Signs and Symptoms Possible history of knee pain/injury Recurrent episodes of painful pseudo-locking Possible snapping and popping Pain with stairs and squatting Little or no swelling No ligamentous laxity Management Treat conservatively w/ RICE and NSAID’s if the result of trauma Recurrent conditions may require surgery

Osteochondral Knee Fractures MOI = twisting, sudden cutting, or direct blow Signs and Symptoms Hear a snap Feeling of giving way Immediate swelling Considerable pain Management Diagnosis confirmed through arthroscopic exam Surgery used to replace fragments in order to avoid joint degeneration and arthritis

Osteochondritis Dissecans MOI = partial or complete separation of articular cartilage and subchondral bone Exact cause is unknown but may include: Blunt trauma, Possible skeletal or endocrine abnormalities, Prominent tibial spine impinging on medial femoral condyle, or Impingement due to patellar facet

Signs and Symptoms Management Aching pain and point tenderness Recurrent swelling Possible locking Possible quadriceps atrophy Management Rest and immobilization for children Surgery may be necessary in teenagers and adults Drilling to stimulate healing, pinning, or bone grafts

Loose Bodies MOI = repeated trauma Signs and Symptoms Management May result due to osteochondritis dissecans, meniscal fragments, synovial tissue damage, or cruciate ligaments injury Signs and Symptoms May become lodged and cause locking or popping Pain Sensation of instability Management If not surgically removed it can lead to conditions causing joint degeneration

Joint Contusions MOI = direct blow Signs and Symptoms Management Severe pain Acute inflammation Loss of movement Swelling If not resolved within a week then a chronic condition may exist (synovitis or bursitis) Ecchymosis Possible capsular damage Management RICE Progress to normal activity following return of ROM Padding for protection

Peroneal Nerve Contusion MOI = compression due to a direct blow Signs and Symptoms Local pain and possible shooting nerve pain Numbness and paresthesia Added pressure may exacerbate condition Generally resolves quickly In the event it does not resolve, it could result in drop foot Management RICE Return to play once symptoms resolve and no weakness is present Padding for fibular head

Bursitis MOI = acute, chronic, or recurrent swelling Prepatellar = continued kneeling Infrapatellar = overuse of patellar tendon Signs and Symptoms Localized swelling that results in ballotable patella Swelling in popliteal fossa may indicate a Baker’s cyst Associated with burse over the semimembranosus or medial head of gastrocnemius Commonly painless and causing little disability May progress and should be treated accordingly Management Eliminate cause RICE and NSAID’s Aspiration and steroid injection if chronic

Patellar Fracture MOI = direct or indirect trauma Signs and Symptoms Semi-flexed position with forceful contraction, which may occur while falling, jumping or running Signs and Symptoms Hemorrhaging and joint effusion Possible capsular tearing, separation of bone fragments, and possible quadriceps tendon tearing due to bone fragments Management X-ray necessary for confirmation RICE and splinting if fracture suspected Refer Possible immobilize for 2-3 months

Patella Subluxation or Dislocation MOI = deceleration with simultaneous cutting in opposite direction (valgus force) Quad pulls the patella out of alignment Repetitive subluxation will impose stress to medial restraints Signs and Symptoms Subluxation Pain, swelling, restricted ROM, and palpable tenderness over adductor tubercle Dislocations Total loss of function

Management Reduction Performed by flexing hip, moving patella medially, and slowly extending the knee Following reduction, immobilize for at least 4 weeks Use crutches Isometric exercises After immobilization period, horseshoe pad with elastic wrap should be used to support patella Rehab focuses on strengthening the muscles around the knee, thigh, and hip Possible surgery to release tight structures Improve postural and biomechanical factors

Infrapatellar Fat Pad MOI = becomes wedged between the tibia and patella Irritated by chronic kneeling, pressure, or trauma Signs and Symptoms Capillary hemorrhaging and swelling Chronic irritation may lead to scarring and calcification Pain below the patellar ligament during knee extension May display weakness, mild swelling, and stiffness during movement

Management Rest Utilize therapeutic modalities for inflammation Avoid irritating activities until inflammation has subsided Utilize therapeutic modalities for inflammation Heel lift to prevent irritation during extension Hyperextension taping to prevent full extension

Chondromalacia patella MOI = softening and deterioration of the articular cartilage Three stages: Swelling and softening of cartilage Fissure of softened cartilage Deformation of cartilage surface Often associated with abnormal tracking Abnormal patellar tracking may be due to genu valgum, external tibial torsion, foot pronation, femoral anteversion, patella alta, shallow femoral groove, increased Q angle, laxity of quad tendon

Signs and Symptoms Management Pain with walking, running, stairs, and squatting Possible recurrent swelling Grating sensation with flexion and extension Pain at inferior border during palpation Management Conservative measures RICE, NSAID’s, isometrics, orthotics to correct dysfunction Surgical possibilities Altering muscle attachments Shaping and smoothing of surfaces Drilling Elevating tibial tubercle

Patellofemoral Stress Syndrome MOI = lateral deviation of patella while tracking in femoral groove May result due to tight structures, pronation, increased Q angle, insufficient medial musculature Signs and Symptoms Tenderness at lateral facet of patella Swelling associated with irritation of synovium Dull ache in center of knee Patellar compression will elicit pain and crepitus Apprehension when patella is forced laterally Management Correct imbalances (strength and flexibility) McConnell taping Lateral retinacular release if conservative measures fail

Osgood-Schlatter Disease, Larsen-Johansson Disease Osgood Schlatter’s is apophysitis at the tibial tubercle MOI = repeated avulsion of patellar tendon Bony callus develops enlarging the tibial tubercle Resolves with aging Larsen Johansson is the result of excessive pulling on the inferior pole of the patella

Signs and Symptoms Management Swelling Hemorrhaging Gradual degeneration of the apophysis due to impaired circulation Pain with kneeling, jumping, and running Point tenderness Management Conservative Reduce stressful activity Possible casting Ice before and after activity Isometerics

Patellar Tendinitis (Jumper’s or Kicker’s Knee) MOI = sudden or repetitive extension Jumping or kicking places tremendous strain on patellar or quadriceps tendon Signs and Symptoms Pain and tenderness at inferior pole of patella 3 phases: 1) pain after activity, 2) pain during and after activity, 3) pain during and after activity that may become constant Management Ice, phonophoresis, iontophoresis, ultrasound, heat Exercise Patellar tendon bracing Transverse friction massage

Patellar Tendon Rupture MOI = sudden, powerful quad contraction Rare unless a chronic inflammatory condition exists resulting in tissue degeneration Occurs primarily at point of attachment Signs and Symptoms Palpable defect Lack of knee extension Considerable swelling and pain (initially) Management Surgical repair is needed Proper conservative treatment of jumper’s knee can minimize chances of occurring

Runner’s Knee & Cyclist’s Knee MOI = repetitive/overuse conditions attributed to mal-alignment and structural asymmetries Signs and Symptoms IT Band Friction Syndrome Irritation at band’s insertion Commonly seen in individual that have genu varum or pronated feet Pes Anserine Tendinitis or Bursitis Result of excessive genu valgum and weak vastus medialis Often occurs due to running with one leg higher than the other Running on a slope or crowned road

Management Correction of mal-alignments Ice before and after activity Utilize proper warm-up and stretching techniques Avoidance of aggravating activities NSAID’s Orthotics

The Collapsing Knee Giving way of knee Result of… Weak quadriceps Chronic instability of ligamentous structures Torn meniscus Loose bodies within the knee Subluxating patella Chondromalacia Due to pain

Prevention of Knee Injuries Total body conditioning is required Strength, flexibility, cardiovascular and muscular endurance, agility, speed and balance Muscles around joint must be conditioned to maximize stability Flexibility and strengthening Must avoid abnormal muscle action through flexibility

ACL Prevention Programs Focus on strength, neuromuscular control, and balance Series of different programs which address balance board training, landing strategies, plyometric training, and single leg performance Can be implemented in rehabilitation and preventative training programs

Shoe Type Change in football footwear has drastically reduced the incidence of knee injuries Shoes with more short cleats does not allow foot to become fixed Still allows for control during running and cutting

Functional and Prophylactic Knee Braces Used to protect MCL Used to prevent further damage to grade 1 and grade 2 ACL sprains Used to protect the ACL following surgery Can be custom molded and designed to control rotational forces

Knee Joint Rehabilitation General Body Conditioning Must be maintained with non-weight bearing activities Weight Bearing Initial crutch use, non-weight bearing Gradual progression to weight bearing while wearing rehabilitative brace Knee Joint Mobilization Used to reduce arthrofibrosis Patellar mobilization is key following surgery CPM units

Neuromuscular Control Flexibility Must be regained, maintained, and improved Muscular Strength Progression of isometrics, isotonics, isokinetics, and plyometrics Incorporate eccentric muscle action Open vs. closed kinetic chain exercises Neuromuscular Control Loss of control is generally due to pain and swelling Through exercise and balance equipment proprioception can be enhanced and regained

Functional Progression Bracing Variety of braces Some used to control for specific injuries while others are designed for specific forces, stability, and providing resistance Typically worn for 3-6 weeks after surgery Used to limit ROM for a period of time Functional Progression Gradual return to sports specific skills Progress with weight bearing, move into walking and running, and then onto sprinting and change of direction

Return to Activity Based on healing process Sufficient time for healing must be allowed Objective criteria should include… Strength assessment ROM measures Functional performance tests

Summary Review anatomy Assessment Injury prevention Injury recognition History, observation, palpation Special Tests Injury prevention Injury recognition Rehabilitation