| Part 1 MRI of the posterolateral corner of the normal knee And the value of oblique coronal scan in the posterolateral cornerObjective: To investigate the MRI findings of the posterolateral corner(PLC)of thenormal knee joint and the clinical significance of oblique coronal scan in PLC.Methods: This study was conducted in 16 young volunteers who were recruited from the Third Affiliated Hospital of Soochow University between May 2016 and June 2016 for MRI examination of the knee,including 9 males and 7 females,aged 22 to 30 years.There was no operative history and trauma and the physical examinations were normal on both sides of theknee.All volunteers were supine and the knee unbent with 10°~15°of slight external rotation.The MRI sequences,including conventional oblique sagittal turbo spin echo(TSE)T1WI,T2 WI,and coronal,oblique sagittal and axial proton density weighted image(PDWI)sequence,were scanned for observation and the morphologic characteristics,attachment points,route,signal strength and the relationship with adjacentstructures of the posterolateral corner of the knee,which was composed of fibular collateral ligament,popliteal tendon,popliteofibular ligament,fabellofibular ligament and arcuate ligament were analyzed.Oblique coronal PDWI were scanned additionally for comparing the display effect with conventionalsequences.Results: Results The specific components of the posterolateral corner of the normal knee that could be clearly identified on PDWI included the fibular collateral ligament,popliteus tendon,popliteofibular ligament,arcuate ligament and fabellofibular ligament.Meanwhile,the displaying rate was 100%(32/32),100%(32/32),87.5%(28/32),81.3%(26/32)and 37.5%(12/32),respectively.The location and route of the fibular collateral ligament was fixed,and this ligament was on average(50.88±4.72)mm in length,(4.72 ±0.33)mm in width of the midpoint and(2.55±0.40)mm in thickness.The popliteal tendon was(45.31±1.66)mm in length,(3.15±0.26)mm in thickness and(3.26±0.39)mm in width at the popliteal hiatus.The popliteofibular ligament was(11.66±0.78)mm in length,(3.24±0.32)mm in width of the midpoint and(1.24±0.11)mm in thickness.The display rate of arcuate ligament and fabellofibular ligament was not high in MRI,and appeared with some variability in attachment point,size,morphologic characteristics due to individual differences.There was no significant difference in the length,width and thickness of the fibular collateral ligament,popliteus tendon,popliteofibular ligament between both sides of the knee(all P values > 0.05),while there was significant difference in the length and thickness of the fibular collateral ligament as well as the length and width of the popliteal tendon between males and females(all P values <0.05).Conclusions Being familiar with the anatomy and the normal magnetic resonance of PLC is helpful to discover the subtle abnormal changes and improve the radiologists ability for diagnosing the PLC injuries.The displaying rate of the lateral collateral ligament and the popliteofibular ligament(on a single picture)in Oblique coronal PDWI was 100% and 85.7%.The popliteal tendon must be observed simultaneously with multiple sequences and multiple level(more than three continuous images)because of its unique spiral anatomy.Conclusion: Being familiar with the anatomy and the normal magnetic resonance of PLC is helpful to discover the subtle abnormal changes and and understanding its normal MRI performance is the most important basis for radiologists to diagnose PLC injuries.Oblique coronal scan can significantly improve the display rate of the fibular collateral ligament and popliteal tendon.Part 2 A Clinical application about the assessment of posterolateral corner injury of the knee with MRIObjective: To investigate the clinical value of the posterolateral corner injury of the knee with MRI.Methods: The study was conducted in 30 patients with acute unilateral knee trauma(< 3 weeks)in the Third Affiliated Hospital of Soochow University from May 2016 to Feb 2017 for MRI examination of the knee,who were highly suspected to have lateral knee instability according to clinical physical examination.All patients were supine and the knee unbent with 10°-15°of slight external rotation.The MRI sequences,including conventional oblique sagittal turbo spin echo(TSE)T1WI,T2 WI,and coronal,oblique sagittal and axial proton density weighted image(PDWI)sequence,were scanned for observating the MRI performance of posterolateral corner from morphologic characteristics,attachment points,route,signal strength,composed of fibular collateral ligament,popliteal tendon,popliteofibular ligament and those injured surrounding structures of the knee.Twenty four patients were treated with arthroscopy or surgery,and results were compared with The MRI findings.Results: 27 patients with acute PLC injury were diagnosed with MRI,incluling 23(85.2%)lateral collateral ligament injuries,22(81.5%)popliteal tendon injuries,22(81.5%)popliteofibular ligament injuries,and no single PLC injury was seen.In this group,all the PLC injuries were combined with injury of cruciate ligament,medial collateral ligament,meniscus,bone marrow edema,fracture and joint effusion,and other knee trauma,including 70.4% combined with anterior cruciate ligament injury,44.4% combined with posterior cruciate ligament injury,7.0% combined with anterior and posterior cruciate ligament injury simultaneously,48.1% combined with medial collateral ligament injury,and 29.6% combined with biceps femoral tendon injury.All posterior cruciate ligament injuries were combined with PLC injury.Some special fractures generally indicate different PLC injuries,such as fractures of the fibular head and Lateralfractures of the tibial plateau.The arthroscopic or surgical results of the patients with PLC injury were in good agreement with the MRI findings.Conclusion: MRI is of great importance in diagnosing PLC injury and directing clinical treatment,especially acting as objective evidence for patients who were combined with other knee injuries and had difficulty experiencing physical examination. |
PDF Full Text Request