Open Access Open Badges Research article

Estimation of return-to-sports-time for athletes with stress fracture – an approach combining risk level of fracture site with severity based on imaging

Oliver Dobrindt1*, Birgit Hoffmeyer2, Juri Ruf1, Max Seidensticker1, Ingo G Steffen1, Frank Fischbach1, Alina Zarva1, Gero Wieners1, Gerhard Ulrich1, Christoph H Lohmann2 and Holger Amthauer1

Author Affiliations

1 Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Magdeburg A.ö.R. Otto-von-Guericke Universität, Leipziger Straße 44, Magdeburg 39120, Germany

2 Orthopädische Universitätsklinik, Universitätsklinikum Magdeburg A.ö.R. Otto-von-Guericke Universität, Leipziger Straße 44, Magdeburg 39120, Germany

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BMC Musculoskeletal Disorders 2012, 13:139  doi:10.1186/1471-2474-13-139

Published: 6 August 2012



The aim was to compare the return-to-sports-time (RTST) following stress fractures on the basis of site and severity of injury. This retrospective study was set up at a single institution. Diagnosis was confirmed by an interdisciplinary adjudication panel and images were rated in a blinded-read setting.


52 athletes (female, n = 30; male, n = 22; mean age, 22.8 years) with stress fracture (SFX) who had undergone at least one examination, either MRI or bone scintigraphy, were included. Magnetic resonance images (MRI) and/or bone scintigraphy (BS) of SFX were classified as either low- or high-grade SFX, according to existing grading systems. For MRI, high-grade SFX was defined as visibility of a fracture line or bone marrow edema in T1-, T2-weighted and short tau inversion recovery (STIR) sequences, with low-grade SFX showing no fracture line and bone marrow edema only in STIR and/or T2-weighted sequences. In BS images, a mild and poorly defined focal tracer uptake represented a low-grade lesion, whereas an intense and sharply marginated uptake marked a high-grade SFX. In addition, all injuries were categorized by location as high- or low-risk stress fractures. RTST was obtained from the clinical records. All patients were treated according to a non-weight-bearing treatment plan and comprehensive follow-up data was complete until full recovery. Two-sided Wilcoxon’s rank sum test was used for group comparisons.


High-risk SFX had a mean RTST of 132 days (d) [IQR 64d – 132d] compared to 119d [IQR 50d – 110d] for low-risk sites (p = 0.19). RTST was significantly longer (p = 0.01) in high-grade lesions [mean, 143d; IQR 66d – 134d] than in low-grade [mean, 95d; IQR 42d – 94d]. Analysis of high-risk SFX showed no difference in RTST (p = 0.45) between high- and low-grade [mean, 131d; IQR 72d – 123d vs. mean, 135d; IQR 63d – 132d]. In contrast, the difference was significant for low-risk SFX (p = 0.005) [low-grade; mean, 61d; IQR 35d – 78d vs. high-grade; mean, 153d; IQR 64d – 164d].


For SFX at low-risk sites, the significant difference in RTST between low- and high-grade lesions allows more accurate estimation of RTST by this approach. Both location of the injury and severity determined by imaging should therefore be considered for prediction of RTST.

Stress fracture; Grading system; Athletes; MRI; Bone scintigraphy