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

Lorenzo Masci ^1*, John Pike ², Frank Malara ², Bev Phillips ¹, Kim Bennell ¹ and Peter D Brukner ¹

¹ University of Melbourne, Australia
² Victoria House, Australia

^* To whom correspondence should be addressed. E-mail: lawrence_masci{at}hotmail.com.

Accepted 22 August 2006

Abstract

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 computerised tomography (CT) 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 SPECT) and MRI. CT was performed if bone scintigraphy was positive.

Results: Seventy-one subjects were recruited. Fifty pars interarticulares in 39 subjects (54.9%) had evidence of active spondylolysis as defined by bone scintigraphy (with SPECT). Of these, 19 pars interarticulares in 14 subjects demonstrated a fracture on CT. The one-legged hyperextension test was neither sensitive nor specific for the detection of active spondylolysis. MRI demonstrated bone stress in 40 out of 50 pars interarticulares detected on bone scintigraphy (with SPECT) indicating reduced sensitivity in detecting bone stress compared to bone scintigraphy (p = 0.001). Conversely, MRI demonstrated 18 out of 19 pars interarticularis fractures detected on CT indicating concordance between imaging modalities (p = 0.345). There was a significant difference between MRI and the gold-standard combination of bone scintigraphy (with SPECT)/CT 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 the gold-standard combination of bone scintigraphy (with SPECT)/CT. Bone scintigraphy (with SPECT) should remain the first-line investigation of active athletes with low back pain followed by limited CT if bone scintigraphy is positive.

Key Words: active spondylolysis, hyperextension, magnetic resonance imaging, MRI

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]