Comparison Between Values Of X-ray Film And MRI In The Diagnosis Of Os Trigonum Syndrome

Objective: To analyze the clinical manifestations and imaging features,especially the MRI features of Os trigonum syndrome,to improve understanding of these findings,and to provide imaging evidence for its clinical diagnosis.Methods:1 General information: Between January 2012 to January 2014,the clinical,X-ray film and MRI data of 72 cases of patients with posterior ankle pain who were treated in Hebei Province Cangzhou Hospital of Integrated traditional and Western Medicine were retrospectively analyzed.Of the 72 patients,45 were males and 27 were females,aged from 17 to 67 years old,with an average age of 44.5 years old.Right ankle was involved in 49 cases,left ankle was involved in 23 cases.The medical history was from 1 months to 3 years.All the 72 patients performed conventional anteroposterior and lateral radiographs and MRI examinations of the ankle joint.2 Data collection: 2.1 Conventional X-ray examination of ankle joint: GE DR8000 X-ray machine was used to take the conventional anteroposterior and lateral radiographs of the ankle joint,taking an automatic milliampere adjustment mode.2.2 MRI examination of ankle join: SIEMENS Verio 3.0T superconductive MRI scanner was used to obtain scans of ankle joint,using a 8 channel head coil.Patients take a supine position with foot advanced to enter the gantry.Scan sequence includes: axial proton density weighted imaging with fat suppression(PD-FS)sequence,sagittal spin echo T1 weighted imaging(SE-T1WI)and proton density weighted imaging with fat suppression(PD-FS)sequences,and coronal fast spin echo T2 weighted imaging(TSE-T2WI)and proton density weighted imaging with fat suppression(PD-FS)sequences.3 Contents of observation and analysis : 3.1 Clinical manifestations: history of posterior ankle injury,history of acute or repeated plantar flexion were recorded.The clinical symptoms and signs such as posterior ankle tenderness,limited ankle joint movement,and plantar flexion force reduction were recorded.3.2 Imaging features: X-ray plain film mainly used to observe and recorde posterolateral talar process or Os trigonum morphology,Os trigonum osteosclerosis,cystic degeneration,and posterior ankle soft tissue swelling;MRI mainly use to observe and recorde Os trigonum or posterior talus bone marrow edema,edema of soft tissue around Os trigonum,posterior ankle synovitis,posterior ankle ligament thickening,tenosynovitis of the flexor hallucis longus,posterior ankle soft tissue swelling.3.3 Using passive plantar flexion test and diagnostic blocking as the diagnostic criteria,72 patients with posterior ankle pain were divided into Os trigonum syndrome(OTS)group and non OTS group.The X-ray film and MRI findings in the OTS group and non OTS group were compared,and features which have differential diagnostic value were selected for calculating and comparing the efficacy of X-ray film and MRI in diagnosing or excluding OTS.4 Statistical methods: SPSS 19 statistical software was used for statistical analysis.Chi-square test was used to compare the difference of clinical manifestations and X-ray film and MRI features between OTS group and non OTS group.The ROC curves of the main X-ray film and MRI features were drawn respectively,and the sensitivity,specificity,Youden index and the area under curve(AUC)for the diagnosis of OTS were calculated.P<0.05 was considered statistically significant.Results: According to the clinical diagnostic criteria of Os trigonum syndrome(OTS),the 72 cases of patients with posterior ankle pain were finally diagnosed as OTS in 25 cases,and non OTS in 47 cases,wherein osteoarthritis in 27 cases,other types of arthritis in 9 cases,posterior tibial tendon tear in 4 cases,and retrocalcaneal bursitis and Achilles tendon lesions in 7 cases.There was significant difference for history of acute or repeated plantar flexion(?~2=14.484,P=0.000)between the OTS group and the non OTS group.There was no significant difference for other clinical manifestations between the OTS group and the non OTS group.There was no significant difference for X-ray plain film findings such as Os trigonum osteosclerosis(?~2=2.947,P =0.086),Os trigonum cystic changes(?~2=3.031,P =0.082)and posterior ankle soft tissue swelling(?~2=1.610,P =0.205),between the OTS group and the non OTS group.For diagnosing OTS with Os trigonum osteosclerosis,the sensitivity was 16%,specificity was 95.7%,Youden index was 0.117,and the area under curve was 0.559.For diagnosing OTS with Os trigonum cystic degeneration,the sensitivity was 12%,specificity was 97.9%,Youden index was 0.099,and the area under curve was 0.547.For diagnosing OTS with posterior ankle soft tissue swelling the sensitivity was 40%,specificity was 74.5%,Youden index was 0.145,and the area under the curve was 0.572.There was significant difference for MRI features such as Os trigonum or posterior talus bone marrow edema(?~2=38.868,P =0.000),edema around Os trigonum(?~2=39.919,P =0.000)and tenosynovitis of the flexor hallucis longus(?~2=8.854,P =0.003),between the OTS group and the non OTS group.There was no significant difference for MRI features such as posterior ankle synovitis(?~2=2.534,P =0.119),posterior ankle ligament thickening(?~2=1.515,P =0.218)and posterior ankle soft tissue swelling(?~2=2.400,P =0.121),between the OTS group and the non OTS group.For diagnosing OTS with bone marrow edema,the sensitivity was 88%,specificity was 87.2%,Youden index was 0.752,and the area under curve was 0.876.For diagnosing OTS with edema around Os trigonum,the sensitivity was 92%,specificity was 85.1%,Youden index was 0.771,and the area under the curve was 0.886.For diagnosing OTS with tenosynovitis of the flexor hallucis longus,the sensitivity was 56%,specificity was 78.7%,Youden index was 0.347,and the area under the curve was 0.674.Conclusion: Using passive plantar flexion test and diagnostic blocking as the gold standard,the diagnostic efficacy of MRI on OTS was obviously higher than that of X-ray film.Among the three main MRI features Os trigonum or posterior talus bone marrow edema and edema around Os trigonum had higher diagnostic value,and can be used as the main MRI signs for diagnosing OTS.Combined with literature,the author believes that the following clinical manifestations and imaging signs can be used to confirm the diagnosis of OTS:(1)history of acute or repeated plantar flexion,(2)posterior ankle pain / tenderness,and aggravated with the ankle joint dorsal or plantar flexion;(3)passive plantar flexion test is positive;(4)Os trigonum is displayed on X-ray film or MRI,(5)Os trigonum or posterior talus bone marrow edema,(6)edema of soft tissue around Os trigonum appear on MRI,with or without FHL tenosynovitis.MRI can be used as an early noninvasive diagnostic method for OTS,and can avoid unnecessary diagnostic blocking.