This study aimed at evaluating the additional stability that is provided by anterior external and internal fixators in an unstable pelvic fracture model (OTA 61-C).
An unstable pelvic fracture (OTA 61-C) was created in 27 synthetic pelves by making a 5-mm gap through the sacral foramina (posterior injury) and an ipsilateral pubic rami fracture (anterior injury). The posterior injury was fixed with either a single iliosacral (IS) screw, a single trans-iliac, trans-sacral (TS) screw, or two iliosacral screws (S1S2). Two anterior fixation techniques were utilized: external fixation (Ex-Fix) and supra-acetabular external fixation and internal fixation (In-Fix); supra-acetabular pedicle screws connected with a single subcutaneous spinal rod. The specimens were tested using a nondestructive single-leg stance model. Peak-to-peak (P2P) displacement and rotation and conditioning displacement (CD) were calculated.
The Ex-Fix group failed in 83.3 % of specimens with concomitant single-level posterior fixation (Total: 15/18–7 of 9 IS fixation, 8 of 9 TS fixation), and 0 % (0/9) of specimens with concomitant two-level (S1S2) posterior fixation. All specimens with the In-Fix survived testing except for two specimens treated with In-Fix combined with IS fixation. Trans-sacral fixation had higher pubic rotation and greater sacral and pubic displacement than S1S2 (p < 0.05). Rotation of the pubis and sacrum was not different between In-Fix constructs combined with single-level IS and TS fixation.
In this model of an unstable pelvic fracture (OTA 61-C), anterior fixation with an In-Fix was biomechanically superior to an anterior Ex-Fix in the setting of single-level posterior fixation. There was no biomechanical difference between the In-Fix and Ex-Fix when each was combined with two levels of posterior sacral fixation.
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Marsh J, Slongo T, Agel J, et al. Fracture and dislocation classification compendium-2007: orthopaedic Trauma Association classification, database and outcomes committee. J Orthop Trauma. 2007;21:S1–133.
Papathanasopoulos A, Tzioupis C, Giannoudis VP, et al. Biomechanical aspects of pelvic ring reconstruction techniques: evidence today. Injury. 2010;41:1220–7.
Dahners LE, Jacobs RR, Jayaraman G, Cepulo AJ. A study of external skeletal fixation systems for unstable pelvic fractures. J Trauma. 1984;24:876–81.
Kellam JF. The role of external fixation in pelvic disruptions. Clin Orthop Relat Res. 1989;241:66–82.
Van Zwienen CMA, van den Bosch EW, van Dijke GAH, et al. Cyclic loading of sacroiliac screws in Tile C pelvic fractures. J Trauma. 2005;58:1029–34.
Bromfield C, Leslie M, Buckley J, et al. when does anterior external fixation enhance construct stability in zone ii sacral fractures? A biomechanical evaluation. In: Orthopaedic Trauma Association Annual meeting, basic science Paper #37; 2011.
Mason WTM, Khan SN, James CL, et al. Complications of temporary and definitive external fixation of pelvic ring injuries. Injury. 2005;36:599–604.
Palmer S, Fairbank AC, Bircher M. Surgical complications and implications of external fixation of pelvic fractures. Injury. 1997;28:649–53.
Kuttner M, Klaiber A, Lorenz T, et al. The pelvic subcutaneous cross-over internal fixator. Unfallchirurg. 2009;112:661–9.
Cole PA, Gauger EM, Anavian J, et al. Anterior pelvic external fixator versus subcutaneous internal fixator in the treatment of anterior ring pelvic fractures. J Orthop Trauma. 2012;26:269–77.
Vigdorchik JM, Esquivel AO, Jin X, et al. Biomechanical stability of a supra-acetabular pedicle screw Internal Fixation device (INFIX) vs External Fixation and plates for vertically unstable pelvic fractures. J Orthop Surg Res. 2012;7:31.
Vigdorchik JM, Esquivel AO, Jin X, et al. Anterior internal fixator versus a femoral distractor and external fixation for sacroiliac joint compression and single stance gait testing: a mechanical study in synthetic bone. Int Orthop. 2013;37:1341–6.
Schildhauer TA, Josten C, Muhr G. Triangular osteosynthesis of vertically unstable sacrum fractures: a new concept allowing early weight-bearing. J Orthop Trauma. 2006;20:S44–51.
Routt ML, Simonian PT, Mills WJ. Iliosacral screw fixation: early complications of the percutaneous technique. J Orthop Trauma. 1997;11:584–9.
Haidukewych GJ, Kumar S, Prpa B. Placement of half-pins for supra-acetabular external fixation: an anatomic study. Clin Orthop Relat Res. 2003;411:269–73.
Hiesterman TG, Hill BW, Cole PA. Surgical technique: a percutaneous method of subcutaneous fixation for the anterior pelvic ring: The pelvic bridge hip. Clin Orthop Relat Res. 2012;470:2116–23.
Moazzam C, Heddings AA, Moodie P, Cole PA. Anterior pelvic subcutaneous internal fixator application. J Orthop Trauma. 2012;26:263–8.
García JM, Doblaré M, Seral B, et al. Three-dimensional finite element analysis of several internal and external pelvis fixations. J Biomech Eng. 2000;122:516–22.
Ponsen K-J, Joosse P, Van Dijke GAH, Snijders CJ. External fixation of the pelvic ring: an experimental study on the role of pin diameter, pin position, and parasymphyseal fixator pins. Acta Orthop. 2007;78:648–53.
Ponson KJ, Hoek van Dijke GA, Joosse P, et al. Improvement of external fixator performance in type C pelvic ring injuries by plating of the pubic symphysis: an experimental study on 12 external fixators. J Trauma. 2002;53:907–12 (discussion 912–913).
Stocks GW, Gabel GT, Noble PC, et al. Anterior and posterior internal fixation of vertical shear fractures of the pelvis. J Orthop Res. 1991;9:237–45.
Hasenboehler EA, Stahel PF, Williams A, et al. Prevalence of sacral dysmorphia in a prospective trauma population: Implications for a “safe” surgical corridor for sacro-iliac screw placement. Patient Saf Surg. 2011;5:8.
Mendel T, Noser H, Kuervers J, et al. The influence of sacral morphology on the existence of secure S1 and S2 transverse bone corridors for iliosacroiliac screw fixation. Injury. 2013;44:1773–9.
No funds were received in support of this work. Implants were kindly donated by Stryker and Zimmer corporations.
Conflict of interest
Erik Mcdonald, BS: no conflict of interest. Alexander A. Theologis, MD: no conflict of interest. Patrick Horst, MD: no conflict of interest. Utku Kandemir, MD: Payment for lectures on speaker’s bureaus (AO North America). Murat Pekmezci, MD: Grants (Stryker, Biomet).
No funds were received in support of this work. As this is a biomechanical study utilizing foam models, approval by the appropriate ethics committee and patient consent were not applicable.
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Mcdonald, E., Theologis, A.A., Horst, P. et al. When do anterior external or internal fixators provide additional stability in an unstable (Tile C) pelvic fracture? A biomechanical study. Eur J Trauma Emerg Surg 41, 665–671 (2015). https://doi.org/10.1007/s00068-014-0482-8
- Pelvic fracture
- External fixation
- Internal fixation
- Biomechanical analysis