The effect of moment arm length on high angled femoral neck fractures (Pauwels’ III)

Matthew S. LePine, William R. Barfield, John D. DesJardins, Langdon A. Hartsock

.

DOI: 10.4236/jbise.2010.35062                

Abstract

This study investigated loads among five fixation types (FT) [three cannulated screws (CS), dynamic hip screws with and without derotational screws (DHS-DS and DHS), and dynamic helical hip screws with and without derotational screws (DHHS-DS and DHHS)] across three fracture moment lengths (ML) in Pauwels’ Type III fractures. Methods: Seventy-five sawbones were tested (5 FT × 5 trials × 3 ML). The study hypothesis was that significant differences in axial loading to failure would be demonstrated when CS was compared with the other four FT at the three MLs. Each construct was exposed to an axial compressive load to failure. Construct failure was defined as 5 mm of migration at the fracture site or fixation failure. Shapiro-Wilk was used to test for data normality. Subsequently, independent t-tests with Bonferroni correction was used for paired comparisons. Results: At fracture Moments A and B there were no statistical differences between CS and the other FT. At fracture Moment C all four FT yielded significantly higher (p ≤ 0.001) loads compared with CS. Conclusions: for basicervical fractures CS is a suboptimal form of fixation compared with DHS and DHHS both with and without derotation screws.

Keywords

Pauwels’ Fracture, Biomechanical Testing, Fixation

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Nilsson, L., Johansson, A. and Stromqvist, B. (1993) Factors predicting healing complications in femoral neck fractures: 138 patients followed for 2 years. Acta Orthopaedica Scandinavica, 64(2), 175-177.
[2]	Parker, M.J. and Dynan, Y. (1998) Is Pauwels’ classification still valid? Injury, 29(7), 521-523.
[3]	Bartonicek, J. (2001) Pauwels’ classification of femoral neck fractures: Correct interpretation of the original. Journal of Orthopaedic Trauma, 15(5), 358-360.
[4]	Pauwels, F. (1976) Biomechanics of the normal and diseased hip. Springer, Berlin.
[5]	Caviglia, H.A., Osorio, P.Q. and Comando D. (2002) Classification and diagnosis of intracapsular fractures of the proximal femur. Clinical Orthopaedics and Related Research, 399(7), 17-27.
[6]	Marti, R.K., Schuller, H.M. and Raaymakers, E.L. (1989) Intertrochanteric osteotomy for non-union of the femoral neck. Journal of Bone and Joint Surgery, 71(5), 782-787.
[7]	Haidukewych, G.J., Liporace, F. and Gaines, R. (2005) Pauwels’ type 3 vertical femoral neck fractures – What is the best fixation device? Orthopaedic Trauma Association 21st Annual Meeting, 21(8), 2005, 130-131.
[8]	Stankewich, C.J., Chapman, J., Muthusamy, R., Quaid, G., Schemitsch, E., Tencer, A. and Ching, R.P. (1996) Relationship of mechanical factors to the strength of proximal femur fractures fixed with cancellous screws. Journal of Orthopaedic Trauma, 10(4), 248-257.
[9]	Weinrobe, M., Stankewich, C.J., Mueller, B., Tencer, A.F. (1998) Predicting the mechanical outcome of femoral neck fractures fixed with cancellous screw: An in vivo study. Journal of Orthopaedic Trauma, 12(1), 27-37.
[10]	Husby, T., Alho, A., Hoiseth, A. and Fonstelien, E. (1987) Strength of femoral neck fixation, comparison of six techniques in cadavers. Acta Orthopaedica Scandinavi- ca, 58(6), 634-637.
[11]	Barnes, R., Brown, J.T., Garden, R.S. and Nicoll, E. (1976) Al subcapital fractures of the femur. Journal of Bone and Joint Surgery, 58B(1), 2-24.
[12]	Bout, C.A., Cannegieter, D.M. and Juttman, J.W. (1997) Percutaneous cannulated screw fixation of femoral neck fractures: The three point principle. Injury, 28(2), 135-139.
[13]	Baitner, A.C., Maurer, S.G., Hickey, D.G., Jazrawi, L.M., Kummer, F.J., Goldman, S. and Koval, K.J. (1999) Vertical shear fractures of the femoral neck. Clinical Orthopaedics & Related Research, 367(65), 300-305.
[14]	Deneka, D.A., Simonian, P., Stankewich, E.D., Chapman, J.R. and Tencer, A.F. (1997) Biomechanical comparison of internal fixation techniques for the treatment of unstable basicervical femoral neck fractures. Journal of Orthopaedic Trauma, 11(2), 337-343.
[15]	LaVelle, D.G. (2003) Delayed union and nonunion of fractures. In: Canale, S.T., Ed., Campbell’s Operative Orthopaedics, St. Louis, (10)3, 3125-3165.
[16]	Aminian, A., Gao, F., Fedoriw, W.W., Zhang, L.Q., Kalainov, D.M. and Mark, B.R. (2007) Vertically orient- ed femoral neck fractures:mechanical analysis of four fi- xation techniques. Journal of Orthopaedic Trauma, 21(8), 544-548.
[17]	Hernefaulk, L. and Messner, K. (1995) Femoral stiffness after osteosynthesis of a subcapital osteotomy in osteoporotic bone: An in vitro comparison of nine fixation methods. Journal of Bone and Joint Surgery, 9(58B), 2- 24, 464-469.
[18]	Kuokkanen, H., Korkala, O., Antti-Poika, I., Tolonen, J., Lehtimaki, M.Y. and Silvennoinen, T. (1991) Three cancellous bone screws versus a screw-angle plate in the treatment of Garden I & II fractures of the femoral neck. Acta Orthopaedica Belgium, 57(1), 53-57.
[19]	Parker, M.J. and Blundell, C. (1998) Choice of implant for internal fixation of femoral neck fractures: Meta- analysis of 25 randomized trials including 4,925 patients. Acta Orthopaedica Scandinavica, 69(2), 138-143.
[20]	Christofolini, L., Vineconti, M., Cappello, A. and Toni, A. (1996) Mechanical validation of whole bone composite femur models. Journal of Biomechanics, 29(4), 525-535.
[21]	Heiner, A.D. and Brown, T.D. (2001) Structural properties of a new design of composite replicate femurs and tibias. Journal of Biomechanics, 34(6), 773-781.
[22]	Choueka, J., Koval, K.J., Kummer, F.J., Crawford, G. and Zuckerman, J.D. (1995) Biomechanical comparison of the sliding hip screw and the dome plunger: Effects of material and fixation design. Journal of Bone and Joint Surgery, 77-B(2), 277-283.
[23]	Goh, J.C.H., Shah, K.M. and Bose, K. (1995) Biomechanical study on femoral neck fracture fixation in relation to bone mineral density. Clinical Biomechanics, 10(6), 304-308.
[24]	Kubiak, E.N., Bong, M., Park, S.S., Kummer, F., Egol, K. and Koval, K.J. (2004) Intramedullary fixation of unstable intertrochanteric hip fractures: One or two lag screws. Journal of Orthopaedic Trauma, 18(1), 12-17.
[25]	Chang, W.S., Zuckerman, J.D., Kummer, F.J. and Frankel, V.H. (1987) Biomechanical evaluation of anatomic reduction versus medial displacement osteotomy in unstable intertrochanteric fractures. Clinical Orthopaedics & Related Research, 225(6), 141-146.
[26]	(1986) Gait analysis. In: McAinsh, T.F., Ed., Physics in Medicine & Biology Encyclopedia: Medical Physics, Bioengineering and Biophysics, Pergamon Press Inc, New York, 1(5), 356.
[27]	Tan, V., Wong, K.L., Born, C.T, Harten, R. and DeLong, W.G. (2007) Two-screw femoral neck fracture fixation: A biomechanical analysis of 2 different confirurations. American Journal of Orthopedics, 36(9), 481-485.
[28]	Chaim, S.H., Mukherjee, D.P., Ogden, A.L., Mayeux, R. H., Sadasivan, K.K. and Albright, J.A. (2002) A biomechanical study of femoral neck fracture fixation with the VHS-Vari-Angle hip fixation system. American Journal of Orthopedics, 31(Suppl 1), 22-24.
[29]	Aboulafia, A.J., Price, M.M., Kennon, R.E. and Hutton, W.C. (1999) A comparison of mechanical strength of the femoral neck following locked intramedullary nailing using oblique versus transverse proximal screws. Journal of Orthopaedic Trauma, 13(3), 160-163.
[30]	Kukla, C., Gaebler, C., Pichl, R.W., Prokesch, R., Heinze, G. and Heinz, T. (2002) Predictive geometric factors in a standardized model of femoral neck fractures. Experimental study of cadaveric human femurs. Injury, 33, 427-433.
[31]	Probe, R. and Ward, R. (2006) Internal fixation of femoral neck fractures. Journal of the Academy of Orthopaedic Surgeons, 14(9), 565-571.
[32]	Liporace, F., Gaines, R., Collinge, C. and Haidukewych, G.J. (2008) Results of internal fixation of Pauwels’ type-3 vertical femoral neck fractures. Journal of Bone and Joint Surgery, 90(A), 1654-1659.