ORIGINAL ARTICLE

Use of the one-legged hyperextension test and magnetic resonance imaging in the diagnosis of active spondylolysis

L Masci¹, J Pike², F Malara², B Phillips¹, K Bennell¹, P Brukner¹

¹ Centre for Health, Exercise and Sports Medicine, University of Melbourne, Melbourne, Victoria, Australia
² MIA Radiology, Victoria House, Melbourne, Victoria, Australia

Correspondence to:
Dr Masci
Centre for Health, Exercise and Sports Medicine, University of Melbourne, Melbourne, Victoria 3010, Australia; lawrence_masci{at}hotmail.com

Background: Active spondylolysis is an acquired lesion in the pars interarticularis and is a common cause of low back pain in the young athlete.

Objectives: To evaluate whether the one-legged hyperextension test can assist in the clinical detection of active spondylolysis and to determine whether magnetic resonance imaging (MRI) is equivalent to the clinical gold standard of bone scintigraphy and computed tomography in the radiological diagnosis of this condition.

Methods: A prospective cohort design was used. Young active subjects with low back pain were recruited. Outcome measures included clinical assessment (one-legged hyperextension test) and radiological investigations including bone scintigraphy (with single photon emission computed tomography (SPECT)) and MRI. Computed tomography was performed if bone scintigraphy was positive.

Results: Seventy one subjects were recruited. Fifty pars interarticulares in 39 subjects (55%) had evidence of active spondylolysis as defined by bone scintigraphy (with SPECT). Of these, 19 pars interarticulares in 14 subjects showed a fracture on computed tomography. The one-legged hyperextension test was neither sensitive nor specific for the detection of active spondylolysis. MRI revealed bone stress in 40 of the 50 pars interarticulares in which it was detected by bone scintigraphy (with SPECT), indicating reduced sensitivity in detecting bone stress compared with bone scintigraphy (p = 0.001). Conversely, MRI revealed 18 of the 19 pars interarticularis fractures detected by computed tomography, indicating concordance between imaging modalities (p = 0.345). There was a significant difference between MRI and the combination of bone scintigraphy (with SPECT)/computed tomography in the radiological visualisation of active spondylolysis (p = 0.002).

Conclusions: These results suggest that there is a high rate of active spondylolysis in active athletes with low back pain. The one-legged hyperextension test is not useful in detecting active spondylolysis and should not be relied on to exclude the diagnosis. MRI is inferior to bone scintigraphy (with SPECT)/computed tomography. Bone scintigraphy (with SPECT) should remain the first-line investigation of active athletes with low back pain followed by limited computed tomography if bone scintigraphy is positive.

Abbreviations: MRI, magnetic resonance imaging; SPECT, single photon emission computed tomography

Keywords: active spondylolysis; magnetic resonance imaging; spondylolysis; hyperextension

---

 

Commentary

C Standaert³

³ Department of Rehabilitation Medicine, University of Washington, Seattle, WA 98195, USA; cjs1{at}u.washington.edu

---

 

Commentary

L Micheli⁴

⁴ Department of Orthopedic Surgery, Children’s Hospital, Boston, MA, USA; michelilyle{at}aol.com

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Jones, T. R., Rao, R. D. (2009). Adult Isthmic Spondylolisthesis. J Am Acad Orthop Surg 17: 609-617 [Abstract] [Full Text]  
• Davis, G, Johnson, E, McCormick, P C, Roger, E P, Ugokwe, K, Benzel, E C, Sears, W R, McCrory, P (2009). Clinics in neurology and neurosurgery of sport: lumbar spine. Sequestrated disc prolapse and disc bulge. Br. J. Sports. Med. 43: 796-801 [Full Text]  
• Purcell, L., Micheli, L. (2009). Low Back Pain in Young Athletes. Sports Health: A Multidisciplinary Approach 1: 212-222 [Abstract] [Full Text]  
• CHURCH, E. J., ODLE, T. G. (2007). Diagnosis and Treatment Of back Pain. radtech 79: 126-151 [Abstract] [Full Text]