Knee Ligament Injuries: Video Based Physical Examination & Imaging Evaluation

Christopher M. Larson MD

Disclosures

• Consultant: Smith & Nephew For Each Ligament Injury

• Review of Ligament Anatomy and Function

• Video Based Physical Examination Tests

• Interpreting Imaging Studies – Stress Radiographs & when they are applicable

Before We Start When to Get Xrays?? Acute Knee Injury Ottawa Rules Pittsburgh Rules (1 or more of these) • Blunt Trauma or Fall • Age > 55yrs • Fibular Head • Plus Either: Tenderness – Age <12 or >55 • Patellar Tenderness or • Knee Flexion < 90 deg – Unable to BW • (4 steps) • Unable to BW – (4 steps) LARGE Hemarthrosis / Effusion after KNEE injury

• Patella Dislocation

• Large , Peripheral Meniscal Tear

• ACL tear or Multiple ligament knee injuries

• Fracture with Intra-articular extension – Femur / Tibia / Patella

• Quadriceps / Patellar Tendon Ruptures ACL = Anterior Cruciate Ligament ACL Anatomy

• ACL :

• Origin = Posterolateral Femur • Insertion = Anteromedial Tibia

ACL Function • Primary Restraint to Anterior Tibial Translation • Best Isolated at 20-30 degrees knee flexion – Its Why Lachman test (20-30 deg) preferred over the Anterior Drawer test (90 deg) – Secondary Restraints • MCL, Posterior Horn Medial Meniscus, Anterolateral Capsule (ALL)

• ACL = Provides Anterolateral Rotatory Stability (Pivot shift) along with: – Lateral Meniscus – Anterolateral Capsule (ALL) – Iliotibial Band

P.E. = Lachman Test

– Knee 20 – 30 deg flexion

– Translation • 1-5mm, 6-10mm,>10mm – End Point • Firm, Soft, Absent

– Compare to the other side!!!!!

– Sensitivity and Specificity = 95% • Katz et al., AJSM 86

P.E. = Anterior Drawer Test – Knee 90 degree flexion • Hamstring Relaxation

• Normally Tibia 1cm anterior to femur – Translation • 1-5mm, 6-10mm,>10mm – End Point • Firm, Soft, Absent – Compare to other side!!!!!!!!

– Sensitivity • Alert 22 - 95% • Anesthetized 50- 95%

P.E. = Pivot Shift Test • More Challenging Test = evaluates ACL rotational Instability – More Difficult in Acute setting – Need to be RELAXED

– Start with knee in extension / IR & Apply an Axial Load & Valgus stress…. bringing the knee into flexion – At 30 to 40 deg = “ITB reduces the anterior tibial subluxation” = = ACL deficient knee

– 0= nl, 1 = glide, 2 = shift, 3 = momentary locking

Imaging = ACL

• MRI = Normal ACL

• MRI = ACL tear

Imaging = ACL

• MRI = Typical Bone Contusions – Lateral Femur – Posterolateral Tibia

• Plain Radiographs = Segond Fx (ALL) = ACL injury PCL = Posterior Cruciate Ligament PCL Anatomy • PCL:

• Origin = Anteromedial Femur

• Insertion = Posterior Tibia

PCL Function • Primary restraint to Posterior Tibial Translation at both 30 & 90 degrees knee flexion

• PCL also helps to Control: – Tibial ER (90 degrees knee flexion)

• Effect of Severe PCL disruption:

– Increased Patellofemoral & Medial Compartment contact pressure

– Decreased load bearing of Menisci • Eventual PF and Medial Arthritis

Physical Examination • Posterior Drawer – Most Sensitive Test for PCL tear

– Tibial Plateau NL 1cm anterior to MFC

– Grade 1 = Tibia Ant to MFC – Grade 2 = Tibia Flush with FC – Grade 3 = Tibia Posterior to FC – Endpoint = Firm, Soft, Absent

Physical Examination • Posterior Sag Test

Normal

– Knee flexed 90 deg – Relax the Quadriceps

– “Positive” = Anterior Tibia Positive sags Posterior to the Femoral Condyles

Positive Physical Examination • Quadriceps Active Test

– Less Sensitive than other PCL tests

– Knee Flexion 90 degrees – Activate the Quad while the foot is fixed

– “Positive” = Anterior translation of a posteriorly subluxated tibia • Daniel et al., JBJS Am 1988

MRI Imaging = PCL

• MRI Normal

MRI = PCL Injuries

• Proximal Avulsion / Peel Off

• Intrasubstance

• Distal Avulsion

• Chronic Tear MRI = Can appear normal again with time PCL Stress Radiographs = Most Accurate

• Increased Translation Compare to Normal Side

• < 6- 8mm = Partial PCL • 8 - 11mm = Isolated Complete PCL • > 12mm = Severe Combined Injury with PLC or Severe Medial Sided Injury Posterolateral Corner Posterolateral Corner / PLC Anatomy • FCL / LCL – Origin Near Lateral Femoral Epicondyle – Insertion Fibular Head

• Popliteus Tendon – Origin anterior / distal on Femur

• PFL – Runs from Popliteus to the Fibula

Posterolateral Corner Function

• FCL / LCL = Primary Restraint to Varus Stress across knee

• FCL & Popliteus = Primary Restraints to Tibial External Rotation @ 30 – 40 degrees knee flexion Physical Examination • Dial Test Cooper et al., ICL ‘91

• Measure thigh foot ER – 30 deg Knee Flexion – 90 deg Knee Flexion • 15 deg difference = significant

• Increased ER at 30 & NOT 90 = Isolated PLC injury

• Increased ER at both 30 & 90 = PLC & PCL vs MCL/PMC

Physical Examination • Posterolateral Drawer Test – Hughston / Norwood 1980

• 90 deg knee flexion

• Increased ER of the Tibia = PLC injury

Physical Examination

• Reverse Pivot Shift – Can be + in 30% of normal – Hypermobility / Varus Alignment

• 90 deg Knee Flexion & Tibia ER • Valgus stress / Axial Load • Extend the knee

• With PLRI the tibia starts posterior and reduces @ 30 deg

Physical Examination • ER Recurvatum Test – Hughston 1976 / 1980 – PLC +- ACL / PCL

• 1. Great Toes of both feet grasped and lifted off the table – + Result = Knee falls into Varus / Hyperextension / ER • 2. Support proximal to the knee and forcefully hyperextend the knee – Evaluate “Heel Height” 3cm diff

Physical Examination • Varus Stress Test • Varus Stress at 0 deg and 20 - 30 deg knee flexion (IR)

• Grade 1 = 0-5mm > opening • Grade 2 = 6-10mm > • Grade 3 = > 10mm

• Pathologic Opening 30 deg but stable at 0 deg = FCL

• Additional Pathologic Opening at 0 deg = FCL / PLC +- Cruciate Ligament

Physical Examination • Fabers / Figure 4 FCL test

• Place the knee into a Figure of 4

• Palpate the FCL and compare to the contralateral side

• Accurate to pick up Isolated FCL tears

MRI Imaging = PLC • Normal – FCL

– Popliteus

– PFL

– Biceps MRI Imaging = PLC Injury

• FCL Injury

• Popliteus Injury

MRI Imaging = PLC Injury

NL PFL Torn PFL

• PFL Injury

• Biceps Femoris Injury / Avulsion

Varus Stress Radiographs • PLC Stress Radiographs

• Increased Gapping Compared to Normal Side

• 2.2mm = FCL Tear

• 4.0mm = Complete PLC Injury

– 70% sensitivity • Kane, Laprade 2018

MCL / Posteromedial Corner MCL / POL Anatomy • Superficial MCL • Origin = Proximal & Posterior to Medial Femoral Epicondyle • Insertion = Tibia 6cm distal to the joint line

• Deep MCL • Close to the Femoral and Tibial Joint surfaces & deep to the sMCL

• POL (Posterior Oblique Ligament) – Posterior to sMCL on Femur – Attachments to the posterior tibia / Capsule / Semimembranosis

MCL / POL Ligament Function • Superficial MCL / sMCL – Primary stabilizer to Valgus stress at 20 to 30 degrees knee flexion – Contributes to Tibial ER control

• Deep MCL – Secondary stabilizer to Valgus Stress

• Posterior Oblique Ligament / POL – Controls Tibial IR in FULL EXTENSION – Stabilizer to Valgus Stress in Full Extension

• Mild increased laxity to Valgus stress in Full Ext = Complete Medial sided injury • High Grade Laxity in Full Ext = additional ACL & or PCL

Physical Examination

• Valgus Stress Test – Sensitivity MCL 86%

• Test @ 0 deg and 20-30 deg knee flexion (ER)

• Pathologic Opening @ 20-30 deg = sMCL

Physical Examination

• Valgus Stress Test – Sensitivity MCL 86%

• Pathologic Opening @ Full Ext (0 deg) = MCL plus POL +- Cruciate Ligament

Physical Examination

• “Slocum Test”

• PMC = secondary stabilizer against Anterior Tibial Translation with Tibial ER

– In ACL Deficient Knee... – Anterior Drawer with ER • Decreased Translation = PMC intact • No Change Translation = PMC Deficiency

Valgus MCL Stress Radiographs

• Increased Gapping Compared to Normal Side (20-30 deg knee flexion)

• 3.2mm = Isolated sMCL

• 9.8mm = High Grade Medial Sided Injury

– Laprade AJSM,2010

MRI Imaging = MCL / POL

Normal • sMCL Normal POL

sMCL

POL sMCL / POL “Tadpole” • dMCL Normal

dMCL = Meniscofemoral

dMCL = Meniscotibial

MRI = sMCL Injury

• sMCL Proximal

• sMCL Midsubstance

• sMCL Distal (Stener)

Anterolateral Ligament (ALL) ALL Anatomy • Tibia Insertion is consistent between studies – Midway between center of GT and Anterior Fibular Head

• Femoral Origin Location is not consistent between Studies – Proximal and Posterior to FCL Origin Indications ALL Reconstruction?? • Revision ACL Setting

• High Grade Pivot Shift

• Generalized Hypermobility

• ?? Chronic ACL or Cutting / Pivoting Athlete or Deep LF notch sign Imaging = ALL

• Radiographic and MRI Segond Injury is well recognized

• Defining the ALL and its Normal Variants and Injury Patterns is still evolving

Medial Patellofemoral Ligament Medial Patellofemoral Ligament / MPFL

• Origin = Medial Femur • Insertion = proximal 1/3 to 1/2 of the Medial Patella

• Primary Stabilizer to lateral patellar translation / stability

• Injured during Patellar Dislocation

• Attenuated or Deficient in the setting of Subluxation

Physical Examination • Patellar Apprehension is tested – Laterally directed pressure on the patella with knee flexion & results in Apprehension when Instability is present

• Regarding Patellar Mobility – > 2 quadrants of lateral patellar translation is considered abnormal

Abnormal Patellar Translation / Dislocation Conclusions • Acute Knee Injuries Can be challenging to define

• A thorough Physical Examination can help lead to an Accurate Diagnosis

• MRI Imaging can help confirm physical examination findings or help determine injury patterns when the examination is challenging secondary to acute pain

• Stress radiographs further define the extent of injury and potential need for surgery in some situations

Thank You!