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2018 Frank Stinchfield Award

Spinopelvic Hypermobility Is Associated With an Inferior Outcome After THA

Examining the Effect of Spinal Arthrodesis

Grammatopoulos, George, BSc, MBBS, DPhil(Oxon), FRCS(Tr & Orth); Gofton, Wade, MD, FRCSC, MEd; Jibri, Zaid, MBCHb, MRCSEd, FRCR; Coyle, Matthew, MD; Dobransky, Johanna, MHK, BSc; Kreviazuk, Cheryl, BA; Kim, Paul R., MD, FRCSC; Beaulé, Paul E., MD, FRCSC

Clinical Orthopaedics and Related Research®: February 2019 - Volume 477 - Issue 2 - p 310–321
doi: 10.1097/CORR.0000000000000367

Background Many patients undergo both THA and spinal arthrodesis, and those patients may not fare as well as those who undergo one procedure but not the other. The mechanisms of how spinal arthrodesis affects patient function after THA remain unclear.

Questions/purposes The aims of our study were to (1) determine how patient-reported outcome measures (PROMs), including the Oxford hip score as well as dislocations and complications compare after THA between patients with and without spinal arthrodesis; (2) characterize sagittal pelvic changes in these patients that occur when moving between different functional positions and test for differences between patients with and without spinal arthrodesis; and (3) assess whether differences in sagittal pelvic dynamics are associated with PROMs, complications, and dislocations after THA.

Methods In this case-control study, we identified 42 patients (60 hips) who had undergone both THA and spinal arthrodesis between 2002 and 2016 and who were available for followup at a minimum of 12 months (mean, 6 ± 5 years) after the later of the two procedures. These cases were case-control-matched for age, gender, and body mass index with 42 patients (60 hips) who underwent only THA and had no known spinal pathology. All patients completed PROMs, including the Oxford hip score, and underwent four radiographs of the pelvis and spinopelvic complex in three positions (supine, standing, and deep-seated). Cup orientation and various spinopelvic parameters, including pelvic tilt and pelvic-femoral angle, were measured. The difference in pelvic tilt between standing and seated allowed for patient classification based on spinopelvic mobility into normal (± 10°-30°), stiff (< ± 10°) or hypermobile (> ± 30°) groups.

Results Compared with the THA-only group, the THA-spinal arthrodesis group had inferior PROMs (Oxford hip score, 33 ± 10 versus 43 ± 6; p < 0.001) and more surgery-related complications (such as dislocation, loosening, periprosthetic fracture or infection, psoas irritation) (12 versus 3; p = 0.013), especially dislocation (5 versus 0; p = 0.023). We detected no difference in change of pelvic tilt between supine and standing positions between the groups. When standing, patients undergoing THA-spinal arthrodesis had greater pelvic tilt (25° ± 11° versus 17° ± 8°; p < 0.001) and the hip was more extended (193° ± 22° versus 185° ± 30°; p = 0.012). We found that patients undergoing THA-spinal arthrodesis were more likely to have spinopelvic hypermobility (12 of 42 versus three of 42; odds ratio, 5.2; p = 0.02) with anterior tilting of the pelvis. Of all biomechanical parameters, only spinopelvic hypermobility was associated with inferior PROMs (Oxford hip score, 35 ± 9 versus 40 ± 7 in normal mobility; p = 0.049) and was also present in dislocating hips that underwent revision despite acceptable cup orientation.

Conclusions In patients with spinal arthrodesis who have undergone THA, spinopelvic hypermobility is associated with inferior outcomes, including hip instability. Spinopelvic hypermobility should be routinely assessed because these patients may have a narrow zone of optimum cup orientation that would require new technology to define and assist the surgeon in obtaining it.

Level of Evidence Level III, therapeutic study.

G. Grammatopoulos, University College London Hospital, London, UK

W. Gofton, Z. Jibri, M. Coyle, J. Dobransky, C. Kreviazuk, P. R. Kim, P. E. Beaulé, The Ottawa Hospital, Ottawa, Ontario, Canada

P. E. Beaulé, The Ottawa Hospital–General Campus, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada, email:

Each author certifies that he or she, or a member of his or her immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.

All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request.

Clinical Orthopaedics and Related Research® neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA approval status, of any drug or device before clinical use.

Each author certifies that his or her institution approved the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research.

The work was performed at The Ottawa Hospital, Ottawa, Canada.

Received November 30, 2018

Received in revised form May 04, 2018

Accepted May 09, 2018

© 2019 Lippincott Williams & Wilkins LWW
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