Joint, Ligament, Nerve Disclosures: Entrapments • Consultant: Bioclinica • Advisory Board: GE, Philips Jon A. Jacobson, M.D. • Book Royalties: Elsevier Professor of Radiology • None relevant to this lecture Director, Division of Musculoskeletal Radiology University of Michigan Note: all images from the textbook Fundamentals of Musculoskeletal Ultrasound are copyrighted by Elsevier Inc. Outline Tibiotalar Joint: effusion •Joint pathology • Anterior evaluation most sensitive – Effusion, infection, inflammatory arthritis • Plantar flexion • Ligament pathology – Anterior talofibular, calcaneofibular, tibiofibular • Hyperechoic fat pad displaced by anechoic or hypoechoic fluid • Nerve entrapment – Tibial nerve • Sensitivity: MRI > US > PF – Morton neuroma Jacobson, JA et al. AJR 1998; 170:1231 Pitfall: normal hyaline cartilage Effusion: tibiotalar joint Tibia Tibia Talus Talus Talus Sagittal Sagittal Axial Sagittal Axial Aspiration 1 Intraarticular Body Synovitis: anterolateral impingement PL/B Fibula Tibia Talus Talus Coronal Sagittal Septic Joint: talonavicular Septic Joint: • Anechoic or hypoechoic distention of joint recesses • May be hyperechoic if complicated – Possible synovitis • US or color Doppler cannot distinguish between septic and aseptic effusion* *Strouse et al. Radiology 1998; 206:731 5th Metatarsal Phalangeal Joint: septic Septic Joint: work up • If anechoic fluid: aspirate – Avoid overlying cellulitis and tenosynovitis • If hypoechoic / heterogeneous: PP – Aspirate and lavage if needed th th 5 MT 5 MT • If no distention: – Depends on clinical suspicion Sagittal Coronal – Follow-up in 24 hours or lavage 2 Synovitis: color flow Complicated Fluid vs. Synovium • Both may appear hypo- or isoechoic Findings that suggest effusion: • Displacement with transducer pressure Tibia • Joint recess collapse w/ joint movement Talus • Negative flow on color Doppler imaging RA Ankle RA ankle No flow Positive flow Inflammatory Arthritis: Inflammatory Arthritis • Gout: 1st MTP joint, others (tarsal) • Non-specific findings: • Rheumatoid: – Joint effusion – MTP joints (especially 5th) – Synovitis: hyperemia – PIP and 1st IP joints – Erosions: pitfalls • Seronegative: reactive arthritis • Rely on history, lab values, and – Variable joint distribution distribution of abnormalities – Inflammatory enthesopathy Gout: Gout: • Monosodium urate crystals: • Joint effusion / synovial hypertrophy • Double contour sign: – Negative birefringence – Monosodium urate crystal icing on cartilage • Stages: • Tophi: – Asymptomatic hyperuricemia – Hyperechoic with hypoechoic rim – Acute gouty arthritis • Erosions: – Interval asymptomatic phase – Adjacent to tophi – Chronic tophaceous gout – Medial 1st metatarsal head 3 Tibiotalar Joint Effusion: gout Gout: synovitis Tibia Talus PP Talus Sagittal Axial MT 1st Metatarsophalangeal Joint Gout: tophus Gout: Double Contour Sign PP Tibia MT Metatarsal Head Proximal Talus Phalanx 1st MTP Joint Ankle Joint T1w T2w Gad 1st Metatarsophalangeal Joint Rheumatoid Arthritis Rheumatoid Arthritis 5th MT Sagittal: dorsal Sagittal: plantar lateral th 5th MT • 5 metatarsal head – Most common site for involvement • Supplement dorsal evaluation with lateral and plantar view Erosion + Synovitis Tranverse Normal Inanc N et al. US Bio Med 2016; 42:865 4 Outline Ligament Tear: • Joint pathology – Effusion, infection, inflammatory arthritis • Hypoechoic & thickened • Ligament pathology • Acute: anechoic fluid tracking through – Anterior talofibular, calcaneofibular, tibiofibular defect indicates full-thickness tear • Nerve entrapment • Cortical avulsion: hyperechoic – Tibial nerve – Morton neuroma Anterior Talofibular Ligament Tear Trauma: ligament • Lateral: – Anterior talofibular: isolated tear in 66% Fib – Calcaneofibular Fibula Talus • 20% calcaneofibular + anterior talofibular – Posterior talofibular: dislocation Patient #1 Patient #2 Patient #3 – Anterior tibiofibular: high ankle sprain Helgason. Radiol Clin N Am 1998; 36:729 Normal Anterior Talofibular Ligament: avulsion Calcaneofibular Ligament Tear PL/B PL/B Calcaneus Patient #2 Fibula Patient #1 Talus Short Axis Long Axis Axial CT Normal 5 Anterior Inferior Tibiofibular Ligament Tear Ligament Tear: • Anterior inferior Tibia tibiofibular ligament: Fibula Tibia – Look for interosseous Fibula Fibula membrane tear if Tibia absent lower fibular fracture Patient #1 Patient #2 – Maisonneuve fracture Long Axis Maisonneuve Fracture Deltoid Ligament Tear MM T T F F Talus Transverse Normal Fibular Fracture Durkee, J Ultrasound Med 2003; 22:1369 Normal Deltoid Ligament Tear: remote Outline • Joint pathology – Effusion, infection, inflammatory arthritis MM • Ligament pathology – Anterior talofibular, calcaneofibular, tibiofibular Talus • Nerve entrapment – Tibial nerve – Morton neuroma Normal 6 Tibial Nerve (TN) TN = tibial nerve • Bifurcates in tarsal tunnel (distal tibia) MPN = medial plantar nerve – Medial plantar nerve (MPN) LPN: lateral plantar nerve – Lateral plantar nerve (LPN) MCN = medial calcaneal nerve • Plantar nerves divide into interdigital nerves ICN = inferior calcaneal nerve – Motor branches: muscles of sole of foot – Sensory: digits (via common and proper plantar digital nerves) Martinoli, RadioGraphics 2000; 20:S199 From: Louisia, Surgical and Radiologic Anatomy, 1999; 21:169. Ganglion Cyst: tarsal tunnel syndrome Tarsal Tunnel Syndrome • Entrapment of tibial nerve F P – Ganglion cyst: most common – Varicose veins, tenosynovitis – Trauma, deformity, coalition, idiopathic • Tibial nerve: FHL – May appear normal – May be hypoechoic and swollen Axial Sagittal Nagaoka, J Ultrasound Med 2005;24:1035 Ganglion Cyst: tarsal tunnel syndrome Tarsal Tunnel Syndrome: Varices Talus Calcaneus Long Axis Short Axis Medial plantar nerve impingement from ganglion cyst originating from middle facet of anterior subtalar joint 7 Morton Neuroma Morton Neuroma: • Hypoechoic 5 mm mass • Interdigital nerve entrapment – Sensitivity: 100% ; Specificity: 83% • Edema, fibrosis, necrosis – Accuracy equal to MRI • 3rd intermetatarsal space > 2nd – Nerve continuity: sagittal plane • Sharp, burning pain from • Intermetatarsal bursa metatarsal head to toes – Associated with neuroma • Females: pliable foot, high-heeled – “Neuroma-bursal complex” narrow-toed shoes From: Martinoli, Quinn T et al. AJR 2000; 174:1723 RadioGraphics Bignotti B et al. Eur Radiol 2015; 25:2254 2000; 20:S199 Cohen SL et al. J Ultrasound Med 2016; 25:3191 Morton Neuroma Technique: • Interdigital space – Transducer: MT • Plantar MT • Dorsal – Normal digital nerve difficult to visualize – Correlate with symptoms Transverse Coronal T1w Morton Neuroma Dynamic Evaluation • Compression Plantar Dorsal – Between transducer and palpation – Bursae (dorsal) compress, neuromas (plantar) do not • Sonographic Mulder Sign – Scan plantar: coronal plane – Neuroma displaces: plantar Dorsal Plantar – Palpable click Torriani M et al. AJR 2003; 180:1121 Zanetti M et al. Radiology 1997; 203:516 8 Dynamic imaging: Mulder’s Maneuver Take Home Points • Joint – Anterior recess – Effusion versus synovitis – Aspirate if concern for infection • Ligament: anatomy • Nerve entrapments – Tarsal tunnel syndrome – Morton: dynamic E-mail: [email protected] Twitter handle: @jjacobsn 9.