Introduction There are two types of subluxation of the proximal tibio- fibular joint (PTFJ): idiopathic and postdislocation. Idio- pathic cases show a bimodal age distribution, being par- ticularly prevalent in young, preadolescent girls, with a gradual decrease in injury frequency as skeletal maturity is approached; the other age group appears to be late 40s and 50s in patients with continued generalized laxity of the ligaments [5]. We report a case with bilateral congen- ital subluxation of the proximal tibiofibular joint and de- scribe the magnetic resonance imaging (MRI) features for the differential diagnosis. Case report An otherwise healthy 12-year-old girl was admitted to our outpa- tient department for bilateral bone prominences on the lateral as- pect of her knees (Fig. 1). The prominences had originally been recognized by her mother when she was 5 years of age, but at that time the mother did not seek medical attention for the child be- cause the knee had a complete, pain-free range of motion and did not interfere with the child’s daily life. The mother was concerned about the appearance of the leg and the possibility of impaired function in the future. Physical examination revealed no generalized ligamentous lax- ity, and both of the knees had a normal range of motion. The prox- imal fibula was prominent and unstable with manual posterior to anterior force applied on the fibula. Radiography revealed bilateral posterior displacement and lateral subluxation of the fibular heads. Computed tomography was performed to rule out the existence of an occult fracture or any skeletal pathology, and no abnormal find- ing was noted except for the bilateral subluxation of the PTFJ. Ad- ditionally, MRI was performed using extremity coil for further evaluation of PTFJ, ligaments, and tendons. On T1-weighted spin- echo (SE) axial images both anterior and posterior tibiofibular lig- aments were completely intact. There was no increased patholo- gical signal in any ligamentous or tendinous structures on T2- weighted SE sagittal, or T1-weighted SE coronal and axial images (Fig. 2). T2-weighted fat-saturation technique was applied to eval- uate articular cartilage, and moderate cartilage hypertrophy was observed. However, neither joint space loss nor subchondral os- seous erosion was detected (Fig. 3). Abstract There appear to be no cri- teria in the differential diagnosis of traumatic and congenital subluxation of the proximal tibiofibular joint in the literature. We report a case with bilateral congenital subluxation of the proximal tibiofibular joint and describe the magnetic resonance imaging features for the differential diagnosis. Keywords Magnetic resonance imaging · Proximal tibiofibular joint · Subluxation KNEE Knee Surg, Sports Traumatol, Arthrosc (2002) 10 : 340–342 DOI 10.1007/s00167-002-0290-2 Murat Bozkurt Erkan Yılmaz Hasan Havıtçıog ˘lu Izge Günal Bilateral congenital subluxation of the proximal tibiofibular joint with magnetic resonance imaging findings: a case report Received: 26 November 2001 Accepted: 20 February 2002 Published online: 19 April 2002 © Springer-Verlag 2002 I. Günal (✉) Rüzgar Sokak, Çankaya Apt. No: 51/20, 35330 Balçova, Izmir, Turkey e-mail: izge.gunal@deu.edu.tr, Tel.: +90-232-2790329, Fax: +90-232-2775211 M. Bozkurt · H. Havıtçıog ˘lu · I. Günal Department of Orthopedics, Dokuz Eylül University Hospital, 35340 Balçova, Izmir, Turkey E. Yılmaz Department of Radiology, Dokuz Eylül University Hospital, 35340 Balçova, Izmir, Turkey