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Lower Extremities. Second Part. Dr Mohamed El Safwany , MD. Intended Learning Outcomes. The student should be able to understand radiological aspects related to lower limb trauma. Knee . Standard Xray projections: AP – evaluate joint space narrowing / calcifications
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Lower Extremities • Second Part Dr Mohamed El Safwany, MD.
Intended Learning Outcomes • The student should be able to understand radiological aspects related to lower limb trauma.
Knee • Standard Xray projections: • AP – evaluate joint space narrowing / calcifications • Lateral –evaluates .Patella / effusions • Special views • Sunrise / merchant view • Tangential / knee flexed/from top-down • Tunnel view • Knee more flexed, looking through the “tunnel created by the femoral condyles
Knee • Most common reasons to order Knee X rays are: - trauma - Degenerative changes MRI: Soft tissues: tendons, ligaments, menisci, and cartilage
The Knee • Ligaments: • Anterior Cruciate Ligament (ACL) • Posterior Cruciate Ligament (PCL) • Medial Collateral Ligament (MCL) • Lateral Collateral Ligament (LCL)
Knee Effusion • X-ray findings: • Best seen on Lateral view • Superior to Patella • Anterior to distal femur • Look for anterior displacement of fat line
Knee Effusion • MRI Sagittal T2 weighted image
Menisci • Crescent shaped fibrocartilagenous structures that are triangular in cross section. • These structures deepen the articular surface of the tibial plateau adding stability to the joint
Meniscal Tear • Most Common injury to the knee requiring surgery • Medial meniscal tears occur 3 times more frequently than lateral meniscal tears • Locked knee requires urgent intervention
MRI ACL , PCL ACL Resist tibial anterior translation PCL Resist tibial posterior translation
MRI MCL Resists Valgus Deformity and damaged by stress valgus
MRI LCL Resists varus deformity and damaged by stress varus
Posterior Cruciate Ligament Tear Caused by hyperextension of knee or direct blow to anterior aspect of flexed knee (Dashboard)
Unhappy Triad • This is the term given to an injury where the ACL, MCL and Medial Meniscus are all three torn. • The mechanism for this injury is usually a lateral blow to the knee with the foot fixed. • 1. ACL tear • 2. MCL tear • 3. Medial meniscus tear
Patellar Tendon Rupture • Exam: • Patient cannot actively extend knee • Palpable defect inferior to patella • Xray:
Patella Dislocation/ Subluxation • Lateral displacement of patella due to complete tear of medial patellar retinaculum
Patellar fractures • Direct blow to patella – fall • Dark lines across the bone in x ray with sharp corners and edges • Repair by fixation pins and wire
Chronic Knee Pain • Degenerative OA • X ray findings • joint space narrowing (Medial common) • Spurs, osteophytes • Sclerotic bony margins
Loose body: disruption of cartilage , single broken piece. • If multiple pieces – synovial chondromatosis
Knee Replacement • Indicated for severe DJD Includes: • Femoral condylar component • Proximal tibial component • Patellar component • AP view may look like components are not touching , the plastic component are not seen on X-ray
Foot • Bones of the foot: • 7 tarsals • Talus • Calcaneus • Navicular • Medial Cuneiform • Intermediate Cuneiform • Lateral Cuneiform • Cuboid • 5 metatarsals • “rays of the foot” • 14 phalanges
Plantar Fasciitis • Plantar fasciitis is the most common foot problem. • It is caused by activity, overuse and aging. • Plantar fasciitis is an inflammation due to repeated overstretching of the plantar fascia ligament (fat pad of the foot), usually at the point where the fascia is attached to the calcaneus.
Plantar Fasciitis • Contributing factors are: • flat feet • high arches • increasing age • sudden weight increase • sudden increase in activity level • running in sand • hereditary factors • Xray: May reveal bony spur at same site • Ultrasound and MRI may help diagnosis
Hallux Valgus • Most common deformity of the foot • Results in excessive valgus angulation of the big toe • The anatomical deformity consists of: • Increased forefoot width • Lateral deviation of the hallux • Prominence of the first metatarsal head
Lisfranc Injury • Fracture and lateral dislocation of 2nd, 3rd,4th and 5th metatarsals relative to the tarsal bones
Jones Fracture/Dancers fracture • Transverse fracture of the 5th metatarsal at the junction of the proximal metaphysis & diaphysis
Comminuted Fracture of proximal phalanx of great toe • XR: • AP/lat/oblique
Fractures of phalanges of lesser toes • XR: • AP/lat/obliq
Stress fracture Callus
Calcaneus Fractures • May be intraarticular or extraarticular • fall or twisting injury & pain localized to hind foot • XR: • AP/lat/obliq/ axial heel Should have CT scan to review extent of fracture • Also do Xray of Lumbar spine due to associated fractures
Calcaneal Fracture X ray CT Internal Fixation
Ankle sprains • Inversion injury= injures lateral structures of ankle • ligament sprained= • 1. Anterior talofibular ligament (front) - tears first • 2. Posterior talofibular ligament (back) - tears second • 3. Calcaneofibular ligament (middle) - tears last US
Ankle fracturesMalleolar fractures • Ankle inversion injury: • Horizontal fibular fracture and oblique medial malleolus fracture • Ankle eversion fracture: • Horizontal medial malleolus fracture with oblique fibular fracture