Series Of Research On High-frequency Ultrasonography In Diagnosis Of Acute Traumatic Lateral Patellar Dislocations

PART ONEClinical value of high-frequency ultrasonography in diagnosis of acute traumatic lateral patella dislocationBackgroundAcute traumatic lateral patellar dislocation(ATLPD) is a common injury that typically occurs in young active patients,and is the third most common cause of traumatic knee hemarthrosis. This injury may result in numerous lesions, and the presence and extent of the concomitant injuries are considered factors determining nonoperative or operative treatment selection, and detailed diagnosis is essential for selecting the proper management.The application of high-frequency ultrasonography in musculoskeletal system is increasingly extensive, but the application of high-frequency ultrasonography in ATLPD has not been reported in China. Forty patients who presented themselves following ATLPD had a high-frequency ultrasonography scan. Both knees were examined, and corresponding sonographic images were compared.The aim of our study was to improve diagnostic accuracy of high-frequency ultrasonography by investigating sonographic manifestations of normal medial patellofemoral ligament(MFPL) and concomitant injuries of ATLPD.ObjectiveTo investigate normal MPFL manifestations and clinical value of high-frequency ultrasonography in diagnosis of concomitant injuries with ATLPD.MethodsBoth knees of40patients with ATLPD were examined by high-frequency ultrasonography, and the corresponding sonographic images of healthy knees were compared to analyze the sonographic findings of concomitant injuries with ATLPD,and the diagnostic accuracy of high-frequency ultrasonography was assessed based on the surgical results in33patients.Results1.Sonographic findings of ATLPD compared with normal healthy kneesHigh-frequency ultrasonography can show MPFL injury,vastus medialis obliquus (VMO) edema and/or elevation,articular cartilage injury of the medial patella and lateral femoral condyle、medial collateral ligament (MCL) injury and knee hemarthrosis. There were37cases of MPFL injuries(92.5%),21cases of VMO injuries(52.5%),24cases of articular cartilage injuries of the medial patella(60%),9cases of articular cartilage injuries of the lateral femoral condyle(22.5%) and3cases of articular cartilage injuries of the femoral trochlear(7.5%),8cases of MCL injuries(20%) and40cases of knee hemarthrosis(100%) in40patients.Elevation of the VMO muscle fibers by measuring the vertical distance from the adductor tubercle to the inferior margin of the VMO muscle in the coronal plane of the adductor tendon and the shortest distance between the cortex of the medial femoral condyle in the sagittal plane were2.3cm (0.7-4.2cm),0.45cm (0.1-2.9cm) respectively. These measurements were significantly larger than the corresponding values(0.75cm(0.3～2.1cm),0.06cm(0.02-0.9cm)) in the control group (P<0.01).2.The accuracy of high-frequency ultrasonography in diagnosis of concomitant injuries with ATLPD. Compared with the surgical results of33patients,the accordance rate of high-frequency ultrasonography in diagnosis of MPFL tear were90.9%(30/33).The sensitivity,specificity of high-frequency ultrasonography in diagnosis of articular cartilage injury were71%,95.6%respectively. The accordance rate of high-frequency ultrasonography in diagnosis of grade Ⅱ,Ⅲ,Ⅳ articular cartilage injury were36%(4/11),82%(9/11),100%(9/9) respectively. The total accordance rate of high-frequency ultrasonography diagnosis on articular cartilage injury was71%(22/31).High-frequency ultrasonography could also diagnose VMO injuries,MCL injuries and knee hemarthrosis correctly compared with surgical results.ConclusionsHigh-frequency ultrasonography can identify MPFL contour,internal echo and adjacent structures clearly, and may reliably detect injuries and classify damage degree of concomitant injuries with ATLPD,including MPFL and VMO injuries,articular cartilage lesions and so on. High-frequency ultrasonography is a cheap,convenient and reliable method in diagnosis of concomitant injuries after ATLPD,especially can be examinated repeatedly and dynamically,which is of significant clinical value in diagnosing concomitant injuries with ATLPD. PART TWOComparative study of high-frequency ultrasonography and MRI in diagnosis of acute traumatic lateral patellar dislocationBackgroundAcute traumatic lateral patellar dislocation(ATLPD) is a common injury that typically occurs in young active patients. This injury may result in numerous lesions, and the presence and extent of the concomitant injuries are considered factors determining nonoperative or operative treatment selection, and detailed diagnosis is essential for selecting the proper management and judging prognosis. Magnetic resonance imaging (MRI) has been applied widely in diagnosing concomitant injuries of ATLPD at home and abroad,and high-frequency ultrasonography has been applied progressively in diagnose patellar dislocation at abroad,while it has rarely been applied in China. The MRI and high-frequency ultrasonography scans of33patients with ATLPD confirmed by surgical results were retrospectively reviewed in our study to investigate the diagnostic value of high-frequency ultrasonography with ATLPD.ObjectiveTo compare manifestations and diagnostic value of high-frequency ultrasonography and MRI of ATLPD.MethodsThe diagnostic accuracy and efficacy of high-frequency ultrasonography and MRI were compared based on the surgical results of of33patients with ATLPD.Results1. Diagnostic results of high-frequency ultrasonography and MRI in medial patellofemoral ligament (MPFL) and articular cartilage injuries with ATLPDThe accordance rate of high-frequency ultrasonography and MRI in diagnosis of MPFL tear were90.9%(30/33),87.9%(29/33) respectively. The sensitivity,specificity and total accordance rate of high-frequency ultrasonography and MRI in diagnosis of articular cartilage injury were71%,95.6%,71%(22/31) and90.3%,100%,90.3%(28/31) respectively.The diagnostic accordance rate of high-frequency ultrasonography and MRI in grade Ⅱ,Ⅲ,Ⅳ articular cartilage injury were36%(4/11),82%(9/11),100%(9/9) and82%(9/11),91%(10/11),100%(9/9) respectively.There was no significant difference between high-frequency ultrasonography and MRI in diagnostic accordance rate of MPFL tear (P>0.05)There were no significant difference between high-frequency ultrasonography and MRI in diagnostic sensitivity, specificity and total accordance rate of articular cartilage injury (P>0.05)There were no significant difference between high-frequency ultrasonography and MRI in diagnostic accordance rate on grade III,IV articular cartilage injury (P>0.05),but was significantly different between high-frequency ultrasound and MRI in diagnostic accordance rate of grade Ⅱ articular cartilage injury (P<0.05)2. High-frequency ultrasonography and MRI diagnosis on other concomitant injurie with ATLPDTwenty cases of VMO injuries,6cases of MCL injuries and33cases of joint hemarthrosis were all identified by high-frequency ultrasonography and MRI.ConclusionsThere was no significant difference between high-frequency ultrasonography and MRI in diagnostic accordance of MPFL injury.There was significant difference between high-frequency ultrasonography and MRI only in diagnostic accordance rate on grade Ⅱ articular cartilage injury,but there was no significant difference between high-frequency ultrasonography and MRI in total diagnostic accordance on articular cartilage injury.Therefore high-frequency ultrasonography can be applied as one of routine methods in diagnosing concomitant injuries with ATLPD. PART THREESonography on Injury of the Medial Patellofemoral Ligament and Articular Cartilage of the Medial Patella after Acute Traumatic Lateral Patellar Dislocation:Injury Patterns,Diagnostic Value and Correlation AnalysisBackgroundAcute traumatic lateral patellar dislocation (ATLPD) is a common injury that typically occurs in young active patients. The incidence of acute lateral patellar dislocations may account for2-3%of all knee injuries. This injury may result in numerous lesions,including contusions or articular cartilage injuries of the lateral femoral condyle and medial patella,injuries of the medial patellofemoral ligament(MPFL) and vastus medialis obliquus (VMO),joint effusion and so on. The detailed diagnosis of range, location and extent of the concomitant injuries are essential for orthopaedists to select proper management and judge prognosis. Although the applications of high-frequency ultrasonography in musculoskeletal system are increasingly extensive, it has been rarely applied in ATLPD compared with magnetic resonance imaging (MRI). According to biomechanical cadaveric studies, the MPFL has been demonstrated to be the major static soft-tissue restraint to lateral patellar translation, providing53%-60%of the total medial restraining force, but there still remain some conflicts about the tear locations of the MPFL with ATLPD. Some studies showed that MPFL tear occurred more commonly at the patellar attachment site with ATLPD, while other studies showed that MPFL tear occurred more commonly at the femoral attachment site. Although there were some studies about the articular cartilage injury of the medial patella, but there were no studies concentrating on the correlation between injuries of the MPFL and articular cartilage of the medial patella based on our review of literatures.ObjectiveThe purpose of this study was to retrospcetively investigate the predilection site of MPFL injury,accordance rate of high-frequency ultrasongraphy in diagnosis of injury of MPFL and articular cartilage of the medial patella,as well as the correlation between the above two injuries to improve diagnostic value of high-frequency ultrasonography in ATLPD.MethodsHigh-frequency sonographic images of49patients with ATLPD proved clinically were reviewed.The diagnostic accordance rate of high-frequency ultrasonography and MRI in MPFL injury,articular cartilage lesion of the medial patella and the predilection site of MPFL injury were assessed based on the surgical results.The χ2-tests were performed for statistical analysis to investigate the correlation between injury pattern of MPFL and articular cartilage of medial patella.Results1. The accordance rate of high-frequency ultrasonography diagnosis on injury of MPFL and articular cartilage of the medial patellaThe accordance rate of high-frequency ultrasonography diagnosis on injury of MPFL and articular cartilage of the medial patella were89.8%(44/49) and80%(24/30) respectively.2.MPFL tear locations with ATLPDMPFL was most easily injured at femoral attachment, secondly at patellar attachment in our study group.3.The correlation between injury patterns of MPFL and articular cartilage of medial patella3.1The correlation between MPFL injury type and articular cartilage lesion of the medial patellaThe incidence rate of chondral lesion and osteochondral lesion in the medial patella were28.6%(6/21) and9.5%(2/21) in patients with partial MPFL tear.The incidence rate of chondral lesion and osteochondral lesion in the medial patella were42.9%(12/28) and35.7%(10/28) in the patients with complete MPFL tear.There was no significant difference between above two types of MPFL injuries for the incidence rate of chondral lesion of the medial patella with ATLPD (χ2=1.053, P=0.305), but the incidence rate of osteochondral lesion between above two types of MPFL injuries was statistically different (χ2=4.451,P=0.035).3.2The correlation between MPFL injury locations and articular cartilage lesion of the medial patellaThe incidence rate of chondral lesion and osteochondral lesion in the medial patella were38.1%(8/21) and28.6%(6/21) in the patients with MPFL tear at patellar attachment, and the incidence rate of chondral injury and osteochondral injury in the medial patella were33.3%(9/27) and22.2%(6/27) in patients with MPFL tear at the femoral attachment.There was no significant difference between above two locations for the incidence rate of chondral or osteochondral lesions of the medial patella with ATLPD (χ2=0.117,P=0.732;χ2=0.254,P=0.614).ConclusionsMPFL is most easily injured at femoral attachment,secondly at patellar attachment after ATLPD. High-frequency ultrasonography is an accurate method in diagnosis of MPFL tear and articular cartilage lesion of the medial patella with ATLPD. There are neither significant differences on incidence rates of chondral or osteochondral lesions of medial patella between locations of MPFL injuries, nor significant difference on incidence rates of chondral lesions between injury types of MPFL, but the complete MPFL tear is more often concomitant with medial patellar osteochondral lesion than partial MPFL tear.