1) To discuss a rare complication of partial entwinement and splitting of the sciatic nerve after closed reduction of a dislocated hip prosthesis and to review the MRI imaging obtained in this case. 2) To discuss the normal anatomy and course of the sciatic nerve along with its variations. 3) To discuss the prevalence of these variants and their detection with MRI.

Sciatic nerve injury is a recognised complication of dislocated prosthetic and native hips, with the incidence varying from 0.7% to 10% 1,2. However, injury to the sciatic nerve after closed reduction of a dislocated hip replacement is rare3,4. To our knowledge, there are only 8 other documented cases of sciatic nerve injuries after closed reduction in the literature 1,3-9. 6 of which have described sciatic nerve entwinement around a total hip replacement (THR) 1,3,5-8. Our case is the only other report so far that describes...

ImagingReview: The pre-reduction plain radiographic films demonstrated a posteriorly dislocated left prosthetic femoral head (Fig. 1) Although mostmetallic implants can be safely imaged withMRI, their presence can cause significant artifacts that result in non-diagnostic images. This is due to theconsequentiallocal field disturbances and large resonant frequency shifts. Aside from the fact that metal has no signal on MRI and appears black, these additional artifacts include signal voids (black areas) and signal pile-ups (bright areas), failure of adjacent fat suppression,and geometric distortion10 (Fig. 2). Metal artefact...

We presented an illustrative case of a rare complication of a split and partially entwined sciatic nerve around the femoral neck prosthesis following closed reduction. Prompt surgical exploration is usually indicated in the presence of new sciatic nerve palsy post-reduction. However, in the presence of equivocal neurological symptoms, a pre-operative metal artifact suppression multiplanar MRI examination can aid in diagnosis. Assessing the sciatic nerve at the level of the ischial tuberosityand alsoits relations with the piriformis muscle are helpful aids when attempting to identify high...

Chan JHH, Ballal MS, Dheerendra S, Sanchez-Ballester, Pydisetty RV. Entrapment of the sciatic nerve following closed reduction of a dislocated revision total hip replacement. J Bone Joint Surg (Br) 2011; 93-B: 274-6. Cornwall R, Radomisli TE. Nerve injury in traumatic dislocation of the hip. Clin Orthop Relat Res 2000; 377: 84-91. Lazansky MG. Complications revisited: the debit side of total hip replacement. Clin Orthop 1973; 95:96-103. Ng J, Marson BA, Broodryk A. Foot drop following closed reduction of a total hip replacement. BMJ Case Rep...

Dr.Chong Yew Ng Radiology Registrar. Department of Radiology, University Hospitals PlymouthNHS Trust. Derriford Road, Plymouth UK. PL6 8DH. Email: [email protected] Dr.Priya Suresh MSK Consultant Radiologist. Department of Radiology, University Hospitals PlymouthNHS Trust. Derriford Road, Plymouth UK. PL6 8DH. Dr.Jenn Wong MSK Radiology Fellow. Department of Radiology, The Robert Jones and Agnes Hunt Orthopaedic Hospital NHS. Gobowen, Oswestry UK. SY10 7AG. Mr. Jonathan Keenan Consultant Orthopaedic Surgeon. Department of Trauma and Orthopaedics, University Hospitals PlymouthNHS Trust. Derriford Road, Plymouth UK. PL6 8DH.