Biomechanical analysis of location of lag screw of a dynamic hip screw in treatment of unstable intertrochanteric fracture.

OBJECTIVE The aim of this study was to assess the most adequate location of a lag screw of a dynamic hip screw in the treatment of an unstable intertrochanteric fracture. METHODS Six pairs of proximal femora obtained from fresh adult cadavers were inflicted with iatrogenic unstable intertrochanteric fractures. Fractures of both sides were stabilized with two different favored locations of a lag screw and tested by a Material Testing System machine with increased loads to evaluate the relative migration of the femoral head. RESULTS There was significant difference (p < 0.05) with less migration of the femoral head by inferior insertion of a lag screw in the frontal plane and central insertion in the coronal plane. CONCLUSIONS Based on theoretical and experimental considerations, the most adequate location of a lag screw of a dynamic hip screw should be inferior in the frontal plane and central in the coronal plane.

[1]  F. Kummer,et al.  Biomechanical comparison of the sliding hip screw and the dome plunger. Effects of material and fixation design. , 1995, The Journal of bone and joint surgery. British volume.

[2]  J. Vroemen,et al.  Biomechanical analysis of the Gamma nail and sliding hip screw. , 1994, Clinical orthopaedics and related research.

[3]  G. Zafiropoulos,et al.  Fractured Gamma nail. , 1994, Injury.

[4]  P. Goldhagen,et al.  A Prospective Comparative Study of the Compression Hip Screw and the Gamma Nail , 1993, Journal of orthopaedic trauma.

[5]  J. Webb,et al.  A prospective randomised comparison of the dynamic hip screw and the gamma locking nail. , 1993, The Journal of bone and joint surgery. British volume.

[6]  F. Kummer,et al.  A biomechanical evaluation of the Gamma nail. , 1992, The Journal of bone and joint surgery. British volume.

[7]  K. Leung,et al.  Gamma nails and dynamic hip screws for peritrochanteric fractures. A randomised prospective study in elderly patients. , 1992, Journal of Bone and Joint Surgery-british Volume.

[8]  E. Bartal,et al.  Treatment of the unstable intertrochanteric fracture. Effect of the placement of the screw, its angle of insertion, and osteotomy. , 1991, The Journal of bone and joint surgery. American volume.

[9]  V. Frankel,et al.  A Biomechanical Analysis of the Sliding Hip Screw: The Question of Plate Angle , 1990, Journal of orthopaedic trauma.

[10]  A. Patwardhan,et al.  Axial loading studies of unstable intertrochanteric fractures of the femur. , 1989, Clinical orthopaedics and related research.

[11]  O. Johnell,et al.  Differences in the incidence of hip fracture. Comparison of an urban and a rural population in southern Sweden. , 1988, Acta orthopaedica Scandinavica.

[12]  R Barmada,et al.  The effect of adjunctive methylmethacrylate on failures of fixation and function in patients with intertrochanteric fractures and osteoporosis. , 1985, The Journal of bone and joint surgery. American volume.

[13]  Laros Gs.  The role of osteoporosis in intertrochanteric fractures. , 1980 .

[14]  S. Doppelt.  The sliding compression screw--today's best answer for stabilization of intertrochanteric hip fractures. , 1980, The Orthopedic clinics of North America.

[15]  A. Sarmiento.  Unstable intertrochanteric fractures of the femur. , 1973, Clinical orthopaedics and related research.

[16]  J. H. Dimon,et al.  Unstable intertrochanteric fractures of the hip. , 1967, The Journal of bone and joint surgery. American volume.