Bano et al. Journal of Medical Case Reports 2010, 4:236 http://www.jmedicalcasereports.com/content/4/1/236 The exact mechanism of this injury is unknown. In tennis players it may result from a strong eccentric stress upon the quadratus femoris muscle in an attempt to control hip internal rotation during the follow- through phase of serving [2]. On the other hand, a con- genitally smaller distance between the lesser trochanter and the ischial tuberosity is a predisposing factor for impingement of the quadratus femoris muscle [8]. The treatment of muscular strain consists of a carefully planned physical rehabilitation programme. In the first days after injury, progressive flexibility and pain-free strengthening exercises for the external hip rotator muscle should be performed. Then, the strengthening exercises are progressed to eccentric loading, as symptoms subside [2]. MRI has an important role in confirming the clinical suspicion, ruling out other soft tissue injuries and aiding prognosis [1,9,10]. Published case reports have shown the correlation of quadratus femoris tendinitis with groin pain [11] and muscle tear with hip pain [1]. According to O’Brien and Bui-Mansfield, axial T2- weighted fat-suppressed magnetic resonance (MR) images have demonstrated the presence of edema between the lesser trochanter and ischial tuberosity. On sagittal T2-weighted fat-suppressed images the edema is localized posterior to the lesser trochanter [1]. We suggest that in our case the grade III, quadratus femoris strain at the tendon-bone junction resulted in an organized mass which compressed the sciatic nerve, simulating piriformis syndrome. To our knowledge, this is the first case of quadratus femoris tear treated by open surgical decompression due to persistent sciatica. Conclusions The primary symptoms of a severe quadratus femoris strain are buttock pain with posterior thigh pain, which is aggravated by sitting or activity, and reproduction of buttock pain on prolonged hip flexion, adduction and internal rotation. MRI is crucial in identifying this unu- sual injury and in excluding damage to neighbouring structures. However, due to the presence of extensive hematoma, imaging may downstage the degree of strain. The above injury should be considered in the differential diagnosis of any patient presenting with proximal thigh pain after injury. The therapy is usually conservative consisting of rehabilitation but, in the case of persisting symptoms, open sciatic nerve decompression should be an alternative approach. Consent Written informed consent was obtained from the patient for publication of this case report and any accompany- ing images. A copy of the written consent is available for review by the Editor-in-Chief of this journal. Page 4 of 4 Author details 1Department of Orthopaedic and Traumatology, University Hospital of Heraklion, 71110, Crete, Greece. 2Department of Radiology, University Hospital of Heraklion, 71110, Crete, Greece. 3Department of Pathology, Medical School, University of Crete, Heraklion, 71003, Greece. 4Department of Histology, Medical School, University of Crete, Heraklion, 71003, Greece. Authors’ contributions DP, AB and PV initiated and co-wrote the paper and performed the surgical treatment of the muscle rupture. AK analyzed the MR images, prepared the illustrations, and performed the proof editing. GD and GT examined the specimen and prepared the histological illustrations of the excised mass. All authors have read and approved the final manuscript. Competing interests The authors declare that they have no competing interests. Received: 4 November 2009 Accepted: 2 August 2010 Published: 2 August 2010 References 1. 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Kassarijian A: Signal abnormalities in the quadratus femoris muscle: tear or impingement. AJR Am J Roentgenol 2008, 190:380-381. 9. Kujula UM, Orava S, Jarvinen M: Hamstring injuries. Current trends in treatment and prevention. Sports Med 1997, 23:397-404. 10. Speer KP, Lohnes J, Garret WE: Radiographic imaging of muscle strain injury. Am J Sports Med 1993, 21:89-96. 11. Klinkert P Jr, Porte RJ, de Rooij TP, de Vries AC: Quadratus femoris tendinitis as a cause of groin pain. Br J Sports Med 1997, 31:348-349. doi:10.1186/1752-1947-4-236 Cite this article as: Bano et al.: Persistent sciatica induced by quadratus femoris muscle tear and treated by surgical decompression: a case report. Journal of Medical Case Reports 2010 4:236. 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