Vinh Chung Gillian Lieberman, MD
July 2001
Sprained Ligaments of the Knee Vinh Chung, Harvard Medical School Year III Gillian Lieberman, MD
Vinh Chung Gillian Lieberman, MD
Agenda • Introduction • Diagnostic Procedures • MRI Images • Our Patient • Summary
2
Vinh Chung Gillian Lieberman, MD
Introduction The knee is the most commonly injured joint • Most common orthopedic problem in the ED with 1.3m ED cases per year • Over 50,000 knee injuries require operations in the U.S. each year • Knees are the most common joints examined by MRI • Injuries continue to increase due to sports activities Roberts, DM. Emergency department evaluation and treatment of knee and leg injuries. Emerg Med Clin North Am. 2000 Feb; 18(1): 67-84, v-vi. 3 Rosen, Peter. Emergency Medicine: Concepts and Clinical Practice, 4th ed., 1998 Mosby-Year Book, Inc. Tandeter, Howard. Acute Knee Injuries: Use of Decision Rules for Selective Radiograph Ordering. American Family Physican. December, 1999. Vol. 60: 9.
Vinh Chung Gillian Lieberman, MD
Ligament Anatomy
Netter, Frank. Atlas of Human Anatomy. Second Edition. Novartis: New Jersey. 1997. P. 475.
4
Vinh Chung Gillian Lieberman, MD
Anterior Cruciate Ligament vs. Posterior Cruciate Ligament
Ligament
Size
Location
Function
ACL
Smaller
Anterior tibia to lateral condyle
Prevent hyperextension and posterior displacement of femur
PCL
Larger
Posterior tibia to medial condyle
Prevent hyperflexion and anterior displacement of femur 5
Vinh Chung Gillian Lieberman, MD
Ligament Injuries Ligament
Force
Cause Frequency
Anterior Cruciate Lateral w/ Knee Extended
Sports
60%
Posterior Cruciate Frontal w/ Knee Flexed
MVA
3-10%
Lateral Collateral Medial
Rare
Medial Collateral Lateral
Common
Southmayd, William. Sports Health: The Complete Book of Athletic Injuries. Quick Fox: New York. 1981. P. 255-8. Rosen, Peter. Emergency Medicine: Concepts and Clinical Practice, 4th ed., 1998. Mosby-Year Book, Inc.
6
Vinh Chung Gillian Lieberman, MD
Meniscus Anatomy • 52% of injuries occur with ACL tears • Failure to repair damage may speed up articular degeneration
Rosen, Peter. Emergency Medicine: Concepts and Clinical Practice, 4th ed., 1998. Mosby-Year Book, Inc. Netter, Frank. Atlas of Human Anatomy. Second Edition. Novartis: New Jersey. 1997. P. 474
7
Vinh Chung Gillian Lieberman, MD
O’Donoghue Triad 1959 Description • Anterior Cruciate Ligament • Medial Collateral Ligament • Medial Meniscus Arthroscopy & MRI • Anterior Cruciate Ligament • Medial Collateral Ligament • Lateral Meniscus Southmayd, William. Sports Health: The Complete Book of Athletic Injuries. Quick Fox: New York. 1981. P. 248 8 Adalberth, T. Magnetic Resonance Imaging, scintigraphy, and arthroscopic evaluation of traumatic hemarthrosis of the knee. Am J Sports Med 1997 Mar-Apr; 25(2): 231-7
Vinh Chung Gillian Lieberman, MD
Treatment • RICE: Rest, Ice, Compression, Elevation • Surgery Severity Grade I Grade II Grade III
Treatment RICE RICE RICE / Surgery
Duration 5 – 14 days 14 – 30 days Months
9
Vinh Chung Gillian Lieberman, MD
Diagnostic Algorithm History / Physical Exam Suspect Arterial Damage
No Diagnosis
Plain Films Arteriogram
Diagnosis Grade III
Grade I or II
Fracture No Fracture
CT
MRI / Arthroscopy
RICE
Treatment Pain
Ultrasound
Diagnosis / Treatment
10
Vinh Chung Gillian Lieberman, MD
History and Physical Exam Advantages • Cheap • Non-invasive • Can identify most knee joint lesions • 90% sensitive in detecting ACL injuries
Disadvantages • 58% accuracy compared with arthroscopy • Very difficult to diagnose: chondral fractures, loose bodies, and fibrotic fat pads • 38-95% accurate in diagnosing ACL injuries
Strobel, Michael. Diagnostic Evaluation of the Knee. Springer-Verlag. 1990. 11 Rosen, Peter. Emergency Medicine: Concepts and Clinical Practice, 4th ed., 1998. Mosby-Year Book, Inc. Tandeter, Howard. Acute Knee Injuries: Use of Decision Rules for Selective Radiograph Ordering. American Family Physican. December, 1999. Vol. 60: 9.
Vinh Chung Gillian Lieberman, MD
Plain Films Advantages • Cheap • Non-invasive • Rules out fractures and foreign bodies
Disadvantages • Overly used: 85% of knee injuries seen in ED get radiographs, but only 612% yield fractures • Cannot image meniscus or ligament
Roberts, DM. Emergency department evaluation and treatment of knee and leg injuries. Emerg Med Clin North Am. 2000 Feb; 18(1): 67-84, v-vi. 12 Tandeter, Howard. Acute Knee Injuries: Use of Decision Rules for Selective Radiograph Ordering. American Family Physican. December, 1999. Vol. 60: 9.
Vinh Chung Gillian Lieberman, MD
Plain Film – ACL Avulsion Bony ligament avulsion apparent at tibial intercondyle eminence
Strobel, Michael. Diagnostic Evaluation of the Knee. Springer-Verlag. 1990.
13
Vinh Chung Gillian Lieberman, MD
CT Athrogram Advantages
Disadvantages
• Excellent for fractures
• Not as good as MRI
• Good for ligament and meniscal tears
Intact ACL
• May be painful
• Used if MRI contraindication Torn ACL Strobel, Michael. Diagnostic Evaluation of the Knee. Springer-Verlag. 1990.
14
Vinh Chung Gillian Lieberman, MD
Arthroscopy • Therapeutically, the most commonly performed orthopedic surgical procedure • Diagnostically, the gold standard for intra-articular pathology of the knee, but has been replaced by MRI Advantages Disadvantages • 84-97% accuracy in • Invasive diagnosing knee pathology • Cannot see posterior • Excellent for treatment meniscal tear • Simultaneous therapy • Difficult to see PCL through ligament debridement or reconstruction Rosen, Peter. Emergency Medicine: Concepts and Clinical Practice, 4th ed., 1998. Mosby-Year Book, Inc.
15
Vinh Chung Gillian Lieberman, MD
MRI Advantages • No radiation
Disadvantages • Expensive, $600-$1,200
• Non-invasive • Highly sensitive and specific for diagnosing ligament and meniscal lesions • Aid for pre-operative planning • Can preclude unnecessary arthroscopy Rosen, Peter. Emergency Medicine: Concepts and Clinical Practice, 4th ed., 1998. Mosby-Year Book, Inc. Gray, Scott. Imaging of the Knee. Current Status. Orthopedic Clinics of North America. October 1997. Volume 28: 4.
16
Vinh Chung Gillian Lieberman, MD
MRI Knee Coil • Knee coils eliminate image distortions • Patient is supine, hip fully extended, and knee slightly flexed • Complete exam takes 20 minutes 17 Strobel, Michael. Diagnostic Evaluation of the Knee. Springer-Verlag. 1990.
Vinh Chung Gillian Lieberman, MD
Normal ACL and PCL ACL
• Visualized as linear low signal ligament strand (blue arrows) • Less homogeneous than PCL • Parallels roof of intercondylar notch (yellow arrows)
PCL
• Uniformly low in signal intensity • Curves superiorly and anteriorly from the tibia to femur
Gray, Scott. Imaging of the Knee. Current Status. Orthopedic Clinics of North America. October 1997. Volume 28: 4. Diagnostic Evaluation of the Knee. Springer-Verlag. 1990.
18
Vinh Chung Gillian Lieberman, MD
Complete ACL Tear • Poorly defined, mixed signal intensity at location where ACL should be. This is due to blood and edema • High intensity (F) is joint effusion Gray, Scott. Imaging of the Knee. Current Status. Orthopedic Clinics of North America. October 1997. Volume 28: 4.
19
Vinh Chung Gillian Lieberman, MD
Acute PCL Tear • High signal intensity wavy fibrids where PCL should be located. This represents hemorrhage and edema
Gray, Scott. Imaging of the Knee. Current Status. Orthopedic Clinics of North America. October 1997. Volume 28: 4.
20
Vinh Chung Gillian Lieberman, MD
Normal Menisci Proton density-weighted sagittal images of two C-shaped menisci with the curves extending peripherally
Lateral meniscus peripherally
Lateral meniscus slightly more centrally resembles a bow-tie
Lateral meniscus centrally through the two horns shows two triangles
Medial meniscus centrally through horns demonstrates two triangles
Thornton, Dean and David A. Rubin. Magnetic Resonance Imaging of the Knee Menisci. Seminars in Roentgenology. Volume:21 35:3. July 2000.
Vinh Chung Gillian Lieberman, MD
Meniscal Tear High signal intensity in posterior horn of medial meniscus extending to the surface indicates clinically significant tear
Gray, Scott. Imaging of the Knee. Current Status. Orthopedic Clinics of North America. October 1997. Volume 28: 4.
22
Vinh Chung Gillian Lieberman, MD
Our Patient HPI:
• 46 year-old white male with a basketball injury of left knee
PE:
• Suggests meniscus tear
Plain Films: • Negative for fractures and bony avulsions An MRI is indicated
23
Vinh Chung Gillian Lieberman, MD
Diagnostic Algorithm History / Physical Exam Suspect Arterial Damage
No Diagnosis
Plain Films Arteriogram
Diagnosis Grade III
Grade I or II
Fracture No Fracture
CT Treatment
RICE
MRI Ultrasound
Pain
Diagnosis / Treatment
24
Vinh Chung Gillian Lieberman, MD
Our Patient: Normal Menisci Menisci are normal in signal intensity and morphology in both lateral and medial compartment. Cartilage is preserved
25
Vinh Chung Gillian Lieberman, MD
Our Patient: Bone Contusions In the lateral compartment, bony contusions involving lateral femoral condyle and proximal tibia
26
Vinh Chung Gillian Lieberman, MD
Our Patient: ACL Tear Increased signal intensity, wavy fibrids where ACL should be. All of these signs suggest complete ACL tear.
27
Vinh Chung Gillian Lieberman, MD
Our Patient: Normal PCL PCL is intact and normal in signal intensity.
28
Vinh Chung Gillian Lieberman, MD
Our Patient: Medial Collateral Ligament: Grade II Sprain There is increased signal intensity surrounding the medial collateral ligament. MCL is partially torn.
29
Vinh Chung Gillian Lieberman, MD
Summary of MRI Findings on our patient Ruled Out:
• Mensical tear
Ruled In:
• Complete ACL tear • Bone contusions • Medial collateral ligament, grade II sprain
30
Vinh Chung Gillian Lieberman, MD
Diagnostic Procedure Comparison HPI / PE
Plain Film
CT
US
ART
MRI
Accuracy:
Risks:
Costs: 31
Vinh Chung Gillian Lieberman, MD
Summary • Knee injuries, especially ligament tears, are very common • History and physical examination are valuable, but sometimes insufficient to diagnose ligament tears • MRI is the superior diagnostic tool for ligament injuries of the knees
32
Vinh Chung Gillian Lieberman, MD
References • • • • • • • •
Adalberth, T. Magnetic Resonance Imaging, scintigraphy, and arthroscopic evaluation of traumatic hemarthrosis of the knee. Am J Sports Med - 1997 Mar-Apr; 25(2): 231-7 Gray, Scott. Imaging of the Knee. Current Status. Orthopedic Clinics of North America. October 1997. Volume 28: 4. Netter, Frank. Atlas of Human Anatomy. Second Edition. Novartis: New Jersey. 1997. Roberts, DM. Emergency department evaluation and treatment of knee and leg injuries. Emerg Med Clin North Am. 2000 Feb; 18(1): 67-84, v-vi. Rosen, Peter. Emergency Medicine: Concepts and Clinical Practice, 4th ed., 1998 Mosby-Year Book, Inc. Strobel, Michael. Diagnostic Evaluation of the Knee. Springer-Verlag. 1990. Tandeter, Howard. Acute Knee Injuries: Use of Decision Rules for Selective Radiograph Ordering. American Family Physican. December, 1999. Vol. 60: 9. Thornton, Dean and David A. Rubin. Magnetic Resonance Imaging of the Knee Menisci. Seminars in Roentgenology. Volume: 35:3. July 2000.
33
Vinh Chung Gillian Lieberman, MD
Acknowledgements Larry Barbaras Cara Lyn D’amour Daniel Lim Daniel Saurborn Leisle Chung
34
