Radiographic Procedures II: Tib/Fib, Knee, & Distal Femur PDF

Radiographic Procedures II Tib/Fib, Knee, & Distal Femur Jena Heflin, MBA, RT(R), CMOM The Lower Leg  Bones  Tibia  Fibula  Patella  Distal Femur  Joints  Ankle  Knee 1 Tibia  Weight-bearing bone of the lower leg  Can be felt through the shin (called the shin bone)  Consists of a body and...

Radiographic Procedures II Tib/Fib, Knee, & Distal Femur Jena Heflin, MBA, RT(R), CMOM The Lower Leg  Bones  Tibia  Fibula  Patella  Distal Femur  Joints  Ankle  Knee 1 Tibia  Weight-bearing bone of the lower leg  Can be felt through the shin (called the shin bone)  Consists of a body and two extremities  Proximal End  Distal End Tibia – Distal End  Smaller than the proximal end  Medial aspect ends in a short, pyramid-shaped process called the medial malleolus  Relates to medial aspect of the ankle  Lateral aspect contains the fibular notch  Flattened, triangular-shaped notch for articulation with the distal fibula  Anterior aspect contains the anterior tubercle  Overlays the fibula 2 Tibia – Proximal End  Contains two prominent processes:  Medial Condyle  Lateral Condyle  Intercondylar Eminence – located between the two condyles  Tibial Plateau  Smooth facets on the superior surface of the condyles  Articulates with the condyles of the femur  Slopes posteriorly 10°-20° Tibia – Proximal End  Anterior Crest  Sharp ridge of bone located along the anterior surface of the tibia  Extends from tibial tuberosity to the medial malleolus  Tibial Tuberosity  Rough-textured prominence  Located on the mid-anterior surface, distal to condyles  Osgood-Schlatter’s Disease  Separation of the tibial tuberosity from the body of the tibia  Occurs most commonly in boys ages 10 - 15 3 Osgood-Schlatter’s Disease Fibula  Located laterally & posteriorly to the tibia  Sometimes called the calf bone  Proximal End  Contains a neck, head, & apex  Head articulates with lateral condyle of tibia  Most proximal end of fibula is the apex  Neck is the tapered area below the head  Distal End  Lateral Malleolus – relates to lateral aspect of ankle joint  Lies 15°-20° more posterior than the medial malleolus 4 Tibia/Fibula Anatomy Patella  a.k.a. Knee Cap  Largest and most constant sesamoid bone  Flat, triangular-shaped bone  About 2 inches in diameter  Contains an apex and a base  Apex – inferior aspect; lies ½ inch above the knee joint  Base – superior aspect  Patella ONLY articulates with the femur (not the tib/fib) 5 Patella Anatomy Distal Femur  Femur is the longest, strongest bone in the entire human body  Contains two eminences:  Medial Condyle (larger)  Lateral Condyle (smaller)  Medial condyle extends 5°-7° lower than the lateral condyle  This is why we angle 5°-7° on AP & Lateral Knee x-rays—to open the joint space of the knee  Contains two surfaces:  Patellar Surface – anterior surface; separates the condyles anteriorly (a.k.a. Intercondylar Sulcus)  Popliteal Surface – posterior surface; superior to the intercondylar fossa 6 Distal Femur  Intercondylar Fossa – separates the condyles distally & posteriorly  Medial & Lateral Epicondyles  Located above the outermost portion of the medial and lateral condyles  Medial epicondyle is more prominent than lateral epicondyle  Adductor Tubercle  Located on the posterolateral aspect of the medial condyle  Receives the tendon of the adductor muscle  Assists in identifying over-rotation or under-rotation on lateral knee x-rays Distal Femur Anatomy Anterior Surface Posterior Surface 7 Joints of the Lower Leg  Ankle Mortise Joint  Synovial, hinge joint  Distal Tibiofibular Joint  Fibrous, syndesmosis joint (slight movement)  Proximal Tibiofibular Joint  Synovial, gliding joint Joints of the Lower Leg Knee Joint:  Patellofemoral Joint  Synovial, gliding joint  Femorotibial Joint  Synovial, hinge (modified) joint  Main joint of the knee 8 Knee Joint  Held together by 4 main ligaments  Posterior Cruciate Ligament (PCL)  Anterior Cruciate Ligament (ACL)  Tibial (Medial) Collateral Ligament (MCL)  Fibular (Lateral) Collateral Ligament (LCL)  Cruciate ligaments stabalize the knee & attach to the intercondylar eminence  Restricts anterior & posterior movements within the knee  Collateral ligaments attach at the sides of the knee joint  Restricts adduction & abduction movements Knee Joint  Largest joint space in the body  Enclosed in an articular capsule or bursa, filled with synovial fluid  Contains two fibrocartilage disks:  Medial Meniscus  Lateral Meniscus  Menisci act as shock absorbers  Located between the tibial plateau and the femoral condyles  MRI or Knee arthrogram used to visualize a torn meniscus 9 Knee Joint Anatomy Anterior Posterior Image Analysis Presentation of radiographs, pertinent anatomy, and positioning criteria. 10 General Considerations  14 x 17 IR for Tib/Fib  10 x 12 IR for Knee & Patella  SID is 40-inches for all views  Shield using full lead apron and thyroid shield  Ensure that apron does not cover the area of interest  No breathing instructions required AP Tib/Fib  Pt. supine or sitting on table  Ankle, knee, and hip on same     plane Femoral condyles parallel to the IR Dorsiflex foot & ankle CR  at midshaft Clip the knee if necessary  May increase SID to 48-inches to include knee joint  If increasing SID doesn’t work, take an additional AP Knee 11 AP Tib/Fib Structures Seen  No rotation  Fibular midshaft free of tibial superimposition  Prox. & distal tib/fib articulations moderately overlapped  Fracture of the distal tibia can indicate a fracture of the proximal fibula Mediolateral Tib/Fib  Roll pt. towards affected side     & flex knee slightly Femoral condyles superimposed Doriflex foot & ankle CR  at midshaft Clip the knee if necessary  May increase SID to 48-inches to include knee joint  If increasing SID doesn’t work, take an additional Lateral Knee 12 Mediolateral Tib/Fib Structures Seen  Moderate separation of the tibial and fibular shafts  Articular ends will overlap  Distal fibula lying over the posterior half of tibia  Slight overlap of the tibia on the proximal fibular head AP Oblique Tib/Fib Projections  From supine position, rotate patient’s entire lower leg 45 medially or laterally Medial rotation  A wedge may be used to assist with the medial rotation  CR  at midshaft  Clip the knee if necessary  May increase SID to 48-inches Lateral rotation to include knee joint  If increasing SID doesn’t work, take an additional Oblique Knee 13 AP Oblique Tib/Fib Projections Structures Seen  Medial Rotation:  Proximal & distal Medial rotation tibiofibular articulations  Maximum space between the tibia and fibula  Lateral Rotation:  Fibula superimposed by the lateral portion of the tibia Lateral rotation AP Knee  Pt. supine or seated  Femoral condyles are parallel to IR  CR enters ½ inch distal to apex of patella  To determine CR angle, measure the pelvis thickness through the ASIS:  < 19 cm: 3-5 caudal (thin pelvis)  19-24 cm: 0 degrees  > 24 cm: 3-5 cephalic (large pelvis) Some protocols may require a standard CR angle of 5 cephalic 14 AP Knee Weight-Bearing  Patient upright  Back against bucky, center knee to IR, place toes straight ahead  Patient places full weight on affect side  Femoral condyles are parallel to IR  CR is  and enters ½ inch distal to apex of patella AP Knee Structures Seen  Open femorotibial joint space  Patella superimposed over femur  No rotation of femur and tibia  Symmetric femoral condyles and tibial intercondylar eminence is centered 15 Medial Oblique Knee  Rotate entire leg 45 medially  CR is ½ inch distal to apex of patella  Utilize same method as AP Knee to determine CR angle  Many protocols may not require an angle on the oblique views Medial Oblique Knee Structures Seen  Proximal tib/fib articulation  Lateral condyles of the femur and tibia  Both tibial plateaus  Patella is shown towards the tibia  Margin of patella projecting slightly beyond the medial side of the femoral condyle 16 Lateral Oblique Knee  Rotate entire leg 45 laterally  CR is ½ inch distal to apex of patella  Utilize same method as AP Knee to determine CR angle  Many protocols may not require an angle on the oblique views Lateral Oblique Knee Structures Seen  Medial condyles of femur and tibia  Tibial plateaus  Fibula superimposed over lateral half of tibia  Patella is shown towards the fibula  Margin of the patella projecting slightly beyond the lateral side of the femoral condyle 17 Mediolateral Knee  Roll pt. toward side of     interest Flex the knee 20-30 degrees Femoral condyles superimposed CR enters 1 inch distal to medial epicondyle Angle 5-7 cephalic Mediolateral Knee Weight-Bearing  Patient upright  Bend affected knee into a 20-30      flexion Patient places full weight on affect side Unaffected leg placed behind affected knee Femoral condyles are superimposed CR enters 1 inch distal to medial epicondyle Angle 5-7 cephalic 18 Mediolateral Knee Structures Seen  Open patellofemoral joint space  Open joint space between femoral condyles and tibia  Fibular head and tibia slightly superimposed  Patella is seen in profile PA Knee  Patient prone with toes resting on table  Femoral condyles parallel to the IR  Angle CR 5-7 caudal  May use  CR if the patient has large thighs when the foot is dorsiflexed  CR is ½ inch distal to apex of patella 19 PA Knee Structures Seen  Open femorotibial joint space  Knee fully extended if pt. condition permits  Slight superimposition of the fibular head with the tibia PA Axial Projection (Holmblad Method – Position 1)  a.k.a. Intercondylar fossa view or Tunnel view  Patient standing with knee flexed and resting on a stool  Flex the knee 70 from full extension  CR  and entering through the patellar apex 20 PA Axial Projection (Holmblad Method – Position 2)  Patient standing at the side of the table with the knee flexed and placed in contact with the front of a vertical IR  Flex the knee 70 from full extension  CR  and entering through the patellar apex PA Axial Projection (Holmblad Method – Position 3)  Patient kneeling on table with knee over IR  Flex the knee 70 from full extension  CR  and entering through the patellar apex 21 PA Axial Projection (Holmblad Method) Structures Seen  Open intercondylar     fossa Posteroinferior surface of femoral condyles Intercondylar eminence and knee joint space Apex of patella NOT superimposing the fossa Slight tib/fib overlap Axial Patella – Settegast Method (a.k.a. Sunrise, Sunset, & Skyline)  Patient has knees bent with feet on the edge of the table  Patient will be holding the IR to match tube angle  CR is 15-20 with the tib/fib, and passes through the patellofemoral joint space  Angle tube with the angle of the leg, then decrease angle (caudally) by 15-20  CR directed through patellofemoral joint space May be done prone 22 Axial Patella – Settegast Method (a.k.a. Sunrise, Sunset, & Skyline) Structures Seen  Patella in profile  Open patellofemoral joint space  Surfaces of femoral condyles  Provides good visualization of a vertical fracture Axial Patella – Merchant Method (a.k.a. Bilateral Tangential Patellae view)  Patient supine with both knees     at the edge of the table Support knees with an adjustable IR-holding device or merchant board Elevate knees 2-inches to place femoral parallel with the tabletop Flex knees 40 CR directed midway between patellae at the level of the patellofemoral joint 23 Axial Patella – Merchant Method (a.k.a. Bilateral Tangential Patellae view) Structures Seen  Bilateral patellae in profile  Femoral condyles and intercondylar sulcus  Open patellofemoral articulations Axial Patella – Hughston Method (a.k.a. Prone Flexion Tangential view)  Patient prone with foot resting     on table Place IR under the patient’s knee and flex the knee to form a 50-60 angle with the table Elevate knees 2-inches to place femoral parallel with the tabletop Angle CR 45 cephalic CR directed through the patellofemoral joint 24 Axial Patella – Hughston Method (a.k.a. Prone Flexion Tangential view) Structures Seen  Open patellofemoral articulation  Surface of the femoral condyles  Shows subluxation of the patella and patellar fractures PA Projection of Patella  Patient prone  Place patella parallel with the plane of the IR  Requires that the heel be rotated 5-10 laterally  CR  to the mid- popliteal area exiting the patella 25 PA Projection of Patella Structures Seen  Patella completely superimposed by the femur  Provides sharper detail than AP due to decreased OID Mediolateral Projection of Patella  Patient rolled onto affected knee  Place femoral condyles  to the IR  Flex knee 5-10  CR  entering at the mid-patellofemoral joint 26 Mediolateral Projection of Patella Structures Seen  Lateral projection of the patella  Open patellofemoral joint space  Patella in profile Critical Thinking What would you do? 27 Situation A knee radiograph is labeled as a medial oblique. The image reveals that the proximal tibia and fibula are superimposed. Is this a true medial oblique knee radiograph? Choice A Choice B Yes, on a medial oblique knee x-ray, the tibia and fibula should be superimposed No, on a medial oblique knee x-ray, the tibiofibular articulation should be visualized Situation A young male patient comes into the radiology department with a clinical history of OsgoodSchlatter’s disease. Which single projection of the basic knee series will best demonstrate this condition? Correct Answer: 28 Situation The technologist has forgotten to label this x-ray on PACS. Which view of the basic knee series is pictured? Correct Answer: Assignment  See course schedule for reading assignment  Study Positioning Notes!  Worksheet  Section 1: Exercise 4 – 13, 15, 17 (Q. 19- 35)  Section 2: Exercise 5, 6, 7, 8, 9 29