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Correlation of Fracture Energy With Sanders Classification and Post-traumatic Osteoarthritis After Displaced Intra-articular Calcaneus Fractures

Rao, Karan, BSE*; Dibbern, Kevin, MS*,†; Day, Molly, MD*; Glass, Natalie, PhD*; Marsh, J. Lawrence, MD*; Anderson, Donald D., PhD*,†

Journal of Orthopaedic Trauma: May 2019 - Volume 33 - Issue 5 - p 261–266
doi: 10.1097/BOT.0000000000001432
Original Article

Objectives: To quantify fracture severity for a series of displaced intra-articular calcaneal fractures (DIACFs) and to correlate it with Sanders classification, post-traumatic osteoarthritis (PTOA), and patient outcomes.

Design: Retrospective review and fracture severity analysis.

Setting: Level 1 trauma center affiliated with the University of Iowa in Iowa City, IA.

Patients/Participants: Thirty-six patients with 48 DIACFs were selected from 153 patients previously treated. All patients 18 years of age and older who had available electronic preop and postop computed tomography (CT) scans, good-quality postop and follow-up radiographs, and a follow-up ≥18 months were selected for study.

Intervention: Fractures were treated with percutaneous reduction, using multiple small stab incisions and fluoroscopy to guide manipulation of articular fragments using cork screws or Steinmann pins, with subsequent fixation using 3.5- and 4.0-mm screws.

Main Outcome Measurements: Preop CT scans were used to grade fractures according to the Sanders classification and to quantify fracture severity. Fracture severity was objectively quantified using a CT-based measure of fracture energy. PTOA was assessed on follow-up radiographs using the Kellgren–Lawrence scale. Patient outcomes were assessed using the Short Form 36 (SF-36) questionnaire and a visual analog scale pain score.

Results: Fracture energies for the 48 DIACFs ranged from 14.1 to 26.2 J (19.3 ± 3.1 J) and correlated with Sanders classification (rho = 0.53, P = 0.0001); type I (16.3 ± 0.9 J); type II (18.0 ± 2.7 J); type III (20.8 ± 2.8 J); and type IV (22.0 ± 0.7 J). Fracture energy was higher for fractures in which the subtalar joint developed PTOA (19.5 ± 2.7 J) than for those that did not (18.9 ± 3.3 J), but the difference did not reach statistical significance. The Sanders classification predicted PTOA risk [odds ratio (OR) = 4.04, 95% confidence interval = 1.43–11.39, P = 0.0084]. No relationship was observed between fracture energy and visual analog scale pain scores. Higher fracture energy correlated with lower SF-36 scores.

Conclusions: Fracture energy positively correlates with Sanders classification for DIACFs, which can be used to identify more severe fractures at greater risk of progressing to PTOA.

Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Departments of *Orthopaedics and Rehabilitation, and

Biomedical Engineering, The University of Iowa, Iowa City, IA.

Reprints: Donald D. Anderson, PhD, University of Iowa, Orthopaedic Biomechanics Laboratory, 2181 Westlawn Building South, Iowa City, IA 52242 (e-mail:

Research reported in this publication was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Number P50 AR055533. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. This work was also supported by the Assistant Secretary of Defense for Health Affairs through the Peer Reviewed Medical Research Program under Award No. W81XWH-15-2-0087. Opinions, interpretations, conclusions, and recommendations are those of the author and are not necessarily endorsed by the Department of Defense.

The authors report no conflict of interest.

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Accepted December 21, 2018

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