Learning Objectives. Lecture Outline. Knee Stability. Cruciate Ligaments. Knee Stability. MRI of the Knee: Part 3: ligaments

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1 Learning Objectives MRI of the Knee: Part 3: ligaments Mark Anderson, M.D. University of Virginia Health System At the end of the presentation, each participant should be able to: describe the anatomy and function of the stabilizing ligaments of the knee as well as their normal appearance on MR images. discuss the common mechanisms and MR appearance of isolated injuries of each of these ligaments. list the most common types of multi-ligament injuries of the knee and the MR findings that will influence the surgical management of these patients Lecture Outline Knee Stability Knee stability Single ligaments - anatomy / pathology - ACL / PCL - medial stabilizers - lateral stabilizers Treatment options Primary motions Flexion / extension Rotation Forces (tibia) Ant / Post Varus / Valgus Int / Ext Rotation Stabilizers Valgus Ant Post Varus Static (ligaments) Dynamic (muscles/tendons) Ext Int Knee Stability Cruciate Ligaments Ligamentous Restraints Anterior ACL (90%) Posterior PCL (95%) Valgus MCL Varus LCL Ext Rotation Popliteus MCL Int Rotation ACL Valgus Ant Post Varus Named for tibial attachments Anterior (lateral) Posterior (medial) A P Ext Int 23

2 ACL: normal anatomy ACL: normal anatomy Lateral notch Functional bundles Femur Anterior tibial plateau A P A anteromedial taut in flexion anterior drawer test posterolateral taut in extension Lachman test resists tibial rotation pivot shift test AM PL AM PL Bicer Kopf EK, S Knee Surg Sports Traumatol Arthrosc ACL: normal MR anatomy Sagittal morphology Taut Parallel intercondylar roof (aka - Blumenstaat s line) Signal intensity Low / intermediate Striated fiber geometry PL AM Evaluate in all planes ACL: other imaging planes Oblique coronal 3D SPACE Oblique axial PL AM 24

3 ACL Injury ACL: complete tear Injuries ~80-250K / year ~100K reconstructions Mechanism 70% - non-contact twisting tibia planted ext femoral rotation valgus (lat impaction) Primary signs edematous mass empty notch irregular, horiz contour focal disruption ACL: complete tear ACL: avulsion Primary signs edematous mass empty notch irregular, horiz contour focal disruption Secondary signs bone contusions deep notch Segond fracture ant tib translation uncovering of PHLM Uncommon injury more common in children adults often hyperextension Subtle findings Treatment conservative arthroscopic fixation status of ligament? 15M baseball injury 35M ACL: partial tear ACL: partial tear Ochi, Arthroscopy ACL tears 10% (17) partial AMB > PLB Clinical exam + ant drawer (flex) = AMB tear + Lachman (ext) = PLB tear minority have + exam Arthroscopy ligament may appear normal hard to assess remaining fibers may miss PLB tear MRI abnormal SI with intact fibers absent / disrupted bundle secondary signs contusions ant tibial translation 67 M knee injury 25

4 PL? AM AM PL MR challenges sensitivity 40-77% specificity 62-89% partial vs. complete normal vs. mild partial high grade partial vs. complete ACL: partial tear ACL: partial tear Van Dyck, Skeletal Radiol, pts 3T: complete vs. partial tears accuracy complete tear 97% partial tear - 95% Couldn t tell partial vs. complete 13% ACL: partial tear ACL: partial tear Chang, Clin Orthp Relat Res, 2013 MRI - isolated bundle tears Accuracy 83% AMB 91% / PLB 78% worse with acute tears Siebold, Arthroscopy 2008 individual bundle repair maintaining other bundle increased vascularization proprioception 49F partial tear of AMB only Ng, Skeletal Radiol, pts conventional planes added oblique axial accuracy standard 74% plus obl axial - 87% 26

5 ACL: partial tear ACL: partial tear 2003 Chen Acta Radiol Importance of preserved, taut fiber(s) 1995 Zeiss JCAT Lateral bone contusions 72% of patients w/complete tears vs 12% w/partial tears 80% of patients with PTs and contusions went on to CT in 6 months Summary abnormal signal intact fibers bone contusions oblique axial images 3T 1997 Chowdhury AJR Stable (normal or low grade tearing) Unstable (high grade or complete tear) Sensitivity 100% Specificity 96% Normal Low grade High Grade Complete ACL: partial tear vs ganglion ACL Reconstruction High signal expanding ligament Celery stalk Drumstick Review articles Bencardino, Radiographics, 2009 Meyers, AJR, 2010 Casagranda, AJR 2009 Surgical options bone / patellar tendon / bone hamstring (4 strand) allograft single vs double bundle Meyers, AJR 2010 Suomalainen AJSM 2011 ACL Reconstruction ACL Reconstruction Graft remodeling tendon ligament 1-2 mos: vascular ingrowth (periph) 2-10 mos: fibroblasts + vessels 1-3 yrs: fibroblasts + vessels 3 yrs: histology similar to ligament Affects MR appearance post op homogeneous low heterogeneous (3-12 mos) 1-2 yrs homogeneous low Tunnels (radiographs) femoral lateral view post cortex Blumensaat s line AP view or 1-2 o clock (classic) anatomic more horizontal skeletally immature physeal sparing 12 6 Ntoulia, Skeletal Radiol

6 Tunnels (radiographs) ACL Reconstruction femoral lateral view post cortex Blumensaat s line AP view or 1-2 o clock (classic) anatomic more horizontal skeletally immature physeal sparing tibial lateral view post to Blumensaat s line Tunnels ACL Reconstruction femoral lat post cortex/blumensaat s line AP or 1-2 o clock tibial lat post to Blumensaat s line widening predominantly in 1 st 6 months usually no clinical impact ACL Reconstruction ACL Graft: complications Tunnels femoral lat post cortex/blumensaat s line AP or 1-2 o clock tibial lat post to Blumensaat s line widening predominantly in 1 st 6 months usually no clinical impact fluid small amounts normal in 1 st year more common with hamstring graft cysts 22% - no clinical impact may extend into soft tissues 3% risk of failure at 2 yrs early poor surgical technique failure of graft incorporation errors in rehabilitation late trauma with new tear Complications tear impingement arthrofibrosis miscellaneous 17M prior ACL recon ACL Reconstruction ACL Reconstruction Tear complete partial stretching most susceptible 4-8 mos MR findings discontinuity partial disruption thickened bowed / lax appearance Secondary signs Clinical exam 17M No instability on exam 17M prior ACL recon 42F Impingement intercondylar roof tibial tunnel too anterior narrow notch / spur sidewall tibial tunnel too lateral PCL femoral tunnel too vertical 28

7 ACL Reconstruction ACL Reconstruction Arthrofibrosis disorganized fibrous tisssue focal (ant) / diffuse cyclops lesion reported incidence: 13-35% clinical loss of extension MR heterogeneous tissue (anterior) Gohil S, et al., 2013 Knee Surg Sports Traumatol Arthosc cyclops lesions (49 patients) 22 (48.6%) cyclops at one yr 17/22 (77%) MRI + / normal exam MR cyclops 5/22 (23%) MRI + / loss of extension clinical cyclops (10% of all pts) 19F rower - asymptomatic ACL Reconstruction PCL Tear Impingement Arthrofibrosis 2X tensile strength of ACL Restricts post tibial translation Taut in flexion Miscellaneous infection patellar fracture hardware loosening fracture displacement Posterior Drawer Arched Homogeneous dark Broad origin Medial notch Compact insertion Between post horns Below joint line MRI: Normal PCL PCL Injury 40% isolated PCL 60% with post-lat corner injury PCL reconstruction? Mechanism of injury Anterior blow to flexed knee Forced hyperflexion 29

8 PCL Injury Medial Stabilizers MRI Findings abnormal signal discontinuity Complete 45% 18M college football recruit Anterior MPFL Middle MCL Posterior Posteromedial Corner posterior oblique ligament semimembranosus posterior horn medial meniscus oblique popliteal ligament AM MG Partial 47% Avulsion 8% Medial side (3 layers) I superficial fascia II superficial MCL / MPFL III deep MCL (meniscus) MPFL: normal anatomy MCL: normal anatomy Primary patellar stabilizer Anatomy Superficial Component part of medial retinaculum just below vastus medialis femoral attachment near adductor tubercle proximal aspect of MCL MCL VM Deep Component meniscofemoral meniscotibial (coronary) Bursa MCL revistaartroscopia.com.ar Ant Posterior Oblique Lig: normal anatomy Posterior to MCL origin just below med gastroc three arms Capsular Central main component reinforces deep MCL attaches to PHMM blends with SM tendon Superficial M CA C L CEN S SM MG 30

9 Semimembranosus: normal anatomy Multiple arms direct postero-medial tibia anterior medial aspect of tibia deep to superficial MCL capsular inferior LaPrade, JBJS 2008 Pes Anserine Tendons: normal anatomy Medial Stability Sartorius Gracilis Semitendinosus S G G ST ST G S S ST S S MPFL resists lateral patellar sublux MCL valgus (flexion) external rotation POL valgus (extension) internal rotation Semimembranosus dynamic Pes Anserine Medial Stability Anteromedial rotatory instability injury to multiple medial structures MCL (deep/superficial) POL often with ACL tear Lateral patellar dislocation impacts lateral femoral condyle Pathology: MPFL medial tibial plateau anterior subluxation external rotation medial joint space opening 31

10 Pathology: MPFL Pathology: MPFL Lateral patellar dislocation impacts lateral femoral condyle Associated injuries bone contusions Lateral patellar dislocation impacts lateral femoral condyle Associated injuries bone contusions cartilage injury patella femur may be low near wgt-bearing surface Pathology: MPFL Mechanism of injury lateral patellar dislocation Associated injuries bone contusions cartilage injury patella femur MPFL injury femur patella both Pathology: MPFL Pathology: MCL Mechanism of injury Associated injuries bone contusions MPFL injury femur patella (fx) both cartilage injury MPFL Reconstruction Two mechanisms valgus force foot planted blow to outside of leg valgus + external rotation Proximal injuries more common than distal nydailynews.com superamazing.net 32

11 Radiographic findings stress views > 10 mm opening tears MCL POL mensicotibial ligament Pathology: MCL Grade Clinical MRI MCL Injury: MRI 1 Sprain Thickened Irregular ST edema Pelegrini-Stieda chronic not always MCL may involve adductor magnus 24F with roller knee derby paininjury MCL Injury: MRI Grade Clinical MRI 1 Sprain Thickened Irregular ST edema 2 Partial Focal SI Tear MCL Injury: MRI Reverse Segond fx Avulsion: coronary ligament PCL and MM tears 33

12 15M baseball injury MCL Injury: MRI Grade Clinical MRI 1 Sprain Thickened Irregular ST edema 2 Partial Focal SI Tear 3 Complete Discontinuity Tear Pathology: MCL 18M injured knee playing football Distal tear poor healing synovial fluid leakage may require surgery Stener lesion of the knee torn fibers superficial to pes anserine tendons Pathology: posteromedial corner Posterior oblique ligament usually injured with other ligaments 20M dirt bike accident Associated injuries semimembranosus (70%) peripheral MM detachment (30%) both (20%) Treatment usually conservative unless mulitligament injury 34

13 Pathology: combined injuries Case 7 More frequent than MCL alone 59F skiing injury MCL + ACL 7-8% lig injuries MCL + PCL <1% lig injuries Posterolateral Corner Posterolateral Corner: what s important? Challenging / complex anatomy the dark side of the knee Difficult physical exam 70% PLC injuries missed initially Pacheco, JBJS 2011 Clinical importance failure to diagnose or treat PLC unstable gait inherently more unstable than medial osteoarthritis (convex surfaces) early failure of cruciate grafts Biceps tendon long head / short head Lateral (fibular) collateral ligament Popliteus muscle / tendon Popliteofibular ligament Popliteomeniscal fascicles Fabellofibular ligament Arcuate ligament Oblique popliteal ligament Iliotibial band Posterolateral Corner: overview Posterolateral Corner: biceps tendon Biceps tendon LCL Iliotibial band Popliteus complex back to front BLT B ITB L P B Long head direct fibular styloid conjoined attachment anterior ant to LCL aponeurosis B popliteus tendon popliteomensical fascicles popliteofibular lig Ant C Post Short head direct fibular head anterior medial to LCL post-lat tibial plateau Ant C 35

14 Posterolateral Corner: LCL Posterolateral Corner: anterolateral lig Lateral femoral condyle above popliteus notch Fibular head styloid process conjoined tendon L C B History 1879 Segond pearly fibrous band 1976 Hughston lat. capsular lig 1986 Irvine ant obl band of the FCL 1986 Terry anterolateral ligament 2000 LaPrade mid 1/3 lat capsular lig 2007 Vieira anterolateral ligament 2012 Vincent - anterolateral ligament LCL Ant Posterolateral Corner: anterolateral lig Anatomy femoral ant / distal to LCL two components LFC to lat meniscus + lat tibia site of Segond fracture LCL + ALL = LCL complex LCL Ligament vs. capsular thickening Adapted from Claes, J Anat 2013 Posterolateral Corner: popliteus complex Posterolateral Corner: popliteus complex Popliteus muscle/tendon Popliteomeniscal fascicles Popliteofibular ligament P Popliteus muscle/tendon dynamic stabilizer origin popliteus notch post-lat LFC between LM and capsule posterior proximal tibia P 36

15 Posterolateral Corner: popliteus complex Posterolateral Corner: popliteus complex Popliteus muscle/tendon Popliteomeniscal fascicles stabilize lateral meniscus form popliteus hiatus three fascicles ant-inferior (floor) post-superior (roof) post-inferior LM Popliteus muscle/tendon Popliteomeniscal fascicles Popliteofibular ligament distal to P-M fascicles fibular head (deep to LCL) popliteus M-T junction below lat inf geniculate vessels P P B B P P From Peduto, AJR 2008 Courtesy of K. Bohndorf Posterolateral Corner: checklist Biceps Lateral Stabilizers: MRI assessment Coronal Axial Sagittal LCL ALL Pop tend Fascicles PFL ITB P B Biomechanics: PLC injury Posterolateral Corner: pathology Mechanisms non-contact twisting external tibial rotation extended knee non-contact hyperextension impact - anteromedial tibia post-lat force PLC involved in 16% of lig injuries Usually with other ligs 87% combined injuries 43% - ACL 28% - PCL 16% - ACL + PCL 12% isolated PLC baltimoresun.com movietvtechgeeks.com 37

16 Posterolateral Corner: pathology Posterolateral Corner: pathology Isolated PLC injuries < 2% of all lig injuries 56% involve > 1 structure LCL + PFL most common LaPrade, 2007 College wrestler felt pop Radiographs lat widening with stress > 2.7 mm isolated LCL > 4.0 mm grade III PLC injury arcuate fracture Segond fracture Gerdy s tubercle avulsion Posterolateral Corner: pathology Posterolateral Corner: pathology MRI Findings evaluate individual ligaments bone contusions ant medial femoral condyle MRI Accuracy ITB, biceps, LCL 90-95% popliteus tendon 85% popliteofibular lig 65% LaPrade, AJSM, 2000 Theodorou, Acta Radiol 2005 MRI: acute vs. chronic < 12 wks (93% detected) > 12 wks (26% detected) Posterolateral Corner: pathology Posterolateral Corner: pathology Multiple ligament injuries Asociated injuries knee dislocation high energy trauma hyperextension ACL PCL other posterior capsule Arterial injury (~30%) 6-8 hour window < 8 hrs = 89% viable > 8 hrs = 86% amputation Nerve injury (20-30%) peroneal tibial s/p knee dislocation popliteal artery (30%) peroneal nerve (20-30%) 38

17 Posterolateral Corner: treatment Posterolateral corner: treatment Early surgery (2-3 wks) better outcomes Reconstruction > repair Three critical structures LCL popliteus tendon popliteofibular ligament Adapted from LaPrade, JBJS M MMA fighter: Someone fell on my knee and bent it backwards. howtobeast.com Case 1 20M collegiate wrestler knee held in varus and felt pop Findings? + post drawer and dial tests INJURIES: PFL / LCL Popliteus muscle PCL (partial) SURGERY: Posterolateral corner reconstruction Case 2 56F twisted knee while skiing + effusion 3+ Lachman 3+ valgus stress INJURIES: ACL / MCL PFL / LCL sprain PHLM fascicles SURGERY: ACL reconstruction PHLM repair (all inside) discoveralta.com 39

18 Case 3 32F who fell while trying to catch her daughter. + Findings? varus stress ++Lachman INJURIES: ACL / high grade PCL LCL / FIB avulsion Popliteus tendon SURGERY: ACL reconstruction Posterolateral corner reconstruction wordpress.com Case 4 20M presented after soccer injury + Lachman Findings? + varus stress ooyala.com INJURIES: ACL Conjoined tendon SURGERY: ACL reconstrustion Posterolateral corner reconstruction 40

19 Case 5 30M who tripped over a pumpkin Findings? while at work INJURIES: ACL / PCL / MCL MPFL LM tear dislocation SURGERY: ACL reconstruction / PCL primary repair PLC reconstruction MCL reconstruction Partial lat meniscectomy omaha.com rmne.org Bonus Case 20F collegiate swimmer with Findings? lateral knee pain Iliotibial Band Friction Syndrome Athletes long distance runners lateral knee pain Abnormal contact ITB lateral femoral condyle passes over LFC with flexion MRI fluid/edema deep to ITB may mimic joint fluid 42F developed lateral knee pain while training for a marathon Posterolateral Corner: checklist Biceps Biceps LCL (ALL) LCL Popliteus Complex ALL tendon fascicles Pop tend popliteofibular ligament Fascicles ITB PFL ITB P B 41

20 Treatment: Single ligament Treatment: Multiple ligaments ACL Partial? PCL MCL Post-lat Corner Reconstruct 3-4 wks unless PLC or locked knee, then within 3 wks Depends on imaging plus clinical exam Isolated = controversial Multiligament = reconstruct Usually non-surgical Distal tear? Surgery within 3 weeks Repair / advance / reconstruct PL AM ACL PCL MCL ACL PCL Post-lat corner Let MCL heal Then reconstruct in 3-4 wks Surgery within 3 weeks Repair / advance / reconstruct Thank You! 42