Effect of Lag-Screw Positions on Modes of Fixation Failure in Elderly Patients with Unstable Intertrochanteric Fractures of the Femur

Abstract

Purpose.

To investigate the effect of lag-screw positions in the femoral head on modes of fixation failure.

Methods.

591 patients aged ≥65 years underwent sliding compression screw fixation for type A₁ (n=249) and type A₂ (n=342) intertrochanteric fractures of the femur after low-energy injuries. There were 18 cases of fixation failure; in 13 (group 1) the lag screw was placed in the central-central area, and in 5 (group 2) in the inferior 1/3-central area. Clinical variables of the 2 groups were compared.

Results.

All 18 cases of fixation failure were actually type A₂₃ and misinterpreted as type A₂₂ fractures. In 13 cases, failure was attributable to cut-out of the lag screws at the superolateral edge of the femoral head. In 3 cases, failure was attributable to telescoping and >2 cm shortening of the femur. In one case, failure was due to penetration of the lag screw into the acetabulum. In another case, failure was due to plate loosening with breakage of cortical screws. In the 13 cases with cut-out of the lag screw (group 1), the lag screw was placed in the central-central area (p<0.001). In the remaining 5 cases with no cut-out (group 2), the lag screw was placed in the inferior 1/3–central area (p<0.01). Complications occurred significantly earlier in group 1 than in group 2 patients (2.6 vs. 4.6 months, p=0.02). The tip-apex distance was significantly shorter in group 1 than in group 2 patients (19 vs. 30 mm, p<0.001).

Conclusion.

Misinterpretation of type A₂₃ fractures as type A₂₂ may lead to fixation failure. Operative treatment should not be delayed once complications occur. The positions of the lag screw may affect the mode of fixation failure.

Keywords

bone screw femoral neck fractures fracture fixation,internal internal fixators

References

Koval

Cantu

. Intertrochanteric fractures. In: Bucholz

Heckman

Court-Brawn

, editors. Rockwood and Green's fractures in adults. Vol II, Philadelphia: Lippincott Williams & Wilkins; 2006:1793–825.

LaVelle

. Fractures and dislocations of the hip. In: Canale

Beaty

, editors. Campbell's operative orthopedics. Vol III, Philadelphia: Mosby; 2008:3287–308.

Kyle

Gustilo

Premer

. Analysis of six hundred and twenty-two intertrochanteric hip fractures. J Bone Joint Surg Am 1979;61:216–21.

Davis

Sher

Horsman

Simpson

Porter

Checketts

. Intertrochanteric femoral fractures. Mechanical failure after internal fixation. J Bone Joint Surg Br 1990;72:26–31.

Den Hartog

Bartal

Cooke

. Treatment of the unstable intertrochanteric fracture. Effect of the placement of the screw, its angle of insertion, and osteotomy. J Bone Joint Surg Am 1991;73:726–33.

Shih

. Biomechanical analysis of the dynamic hip screw in the treatment of intertrochanteric fractures. Arch Orthop Trauma Surg 1991;110:307–10.

Parker

. Cutting-out of the dynamic hip screw related to its position. J Bone Joint Surg Br 1992;74:625.

Shih

Lee

Tai

. Biomechanical analysis of location of lag screw of a dynamic hip screw in treatment of unstable intertrochanteric fracture. J Trauma 1996;41:699–702.

Shih

Chen

Tai

. Treatment of cutout of a lag screw of a dynamic hip screw in an intertrochanteric fracture. Arch Orthop Trauma Surg 1998;117:193–6.

10.

Sim

Schmiedmayer

Lugner

. Mechanical factors responsible for the obstruction of the gliding mechanism of a dynamic hip screw for stabilizing pertrochanteric femoral fractures. J Trauma 2000;49:995–1001.

11.

Fracture and dislocation compendium. Orthopedic Trauma Association Committee for Coding and Classification. J Orthop Trauma 1996;10(Suppl 1):S1–154.

12.

Lau

Lee

Tang

Lim

Chow

. Treatment of comminuted trochanteric femoral fractures with Dimon Hughston displacement fixation and acrylic cement—a preliminary report of sixteen cases. Injury 1983;15:129–35.

13.

Steinberg

Desai

Kornwitz

Sullivan

. The intertrochanteric hip fracture. A retrospective analysis. Orthopedics 1988;11:265–73.

14.

Palm

Jacobsen

Sonne-Holm

Gebuhr

; Hip Fracture Study Group. Integrity of the lateral femoral wall in intertrochanteric hip fractures: An important predictor of a reoperation. J Bone Joint Surg Am 2007;89:470–5.

15.

Moore

. Clinically oriented anatomy. 3rd ed. Baltimore: Williams & Wilkins; 1992:373–500.

16.

Snell

. Clinical anatomy for medical students. 4th ed. Boston: Little, Brown and Company; 1992:507–630.

17.

Hall-Craggs

. Anatomy: As a basis for clinical medicine. London: Williams & Wilkins Waverly Europe; 1995:351–435.

18.

Bryan

. Skeletal anatomy. New York: Churchill Livingstone; 1996:195–241.

19.

Mathers

Jr Chase

Dolph

Glasgow

Gosling

. Clinical anatomy principles. St. Louis: Mosby; 1996:637–62.

20.

Epstein

. Traumatic dislocations of the hip. Clin Orthop Relat Res 1973;92:116–42.

21.

Simpson

Varty

Dodd

. Sliding hip screws: Modes of failure. Injury 1989;20:227–31.

22.

Berry

. Salvage of failed hip fractures with hip replacement. Orthopedics 2002;25:949–50.

23.

Baumgaertner

Curtin

Lindskog

Keggi

. The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip. J Bone Joint Surg Am 1995;77:1058–64.

24.

Baumgaertner

Solberg

. Awareness of tip-apex distance reduces failure of fixation of trochanteric fractures of the hip. J Bone Joint Surg Br 1997;79:969–71.

25.

Cole

Ansel

. Intramedullary nail and lag-screw fixation of proximal femur fractures. Operative technique and preliminary results. Orthop Rev 1994;(Suppl):S35–44.

26.

Jensen

Tondevold

Mossing

. Unstable trochanteric fractures treated with the sliding screw-plate system. A biomechanical study of unstable trochanteric fractures. III. Acta Orthop Scand 1978;49:392–7.

27.

Apel

Patwardhan

Pinzur

Dobozi

. Axial loading studies of unstable intertrochanteric fractures of the femur. Clin Orthop Relat Res 1989;246:156–64.

28.

Bergmann

Deuretzbacher

Heller

Graichen

Rohlmann

Strauss

. Hip contact forces and gait patterns from routine activities. J Biomech 2001;34:859–71.

29.

Ehmke

Fitzpatrick

Krieg

Madey

Bottlang

. Lag screws for hip fracture fixation: Evaluation of migration resistance under simulated walking. J Orthop Res 2005;23:1329–35.

30.

Choueka

Koval

Kummer

Crawford

Zukerman

. Biomechanical comparison of the sliding hip screw and the dome plunger. Effects of material and fixation design. J Bone Joint Surg Br 1995;77:277–83.

31.

Kyle

Wright

Burstein

. Biomechanical analysis of the sliding characteristics of compression hip screws. J Bone Joint Surg Am 1980;62:1308–14.

32.

Shin

Song

. Potentially unstable intertrochanteric fractures. J Orthop Trauma 2005;19:5–9.

33.

Volz

. Biomechanics update #2. Basic biomechanics: Lever arm, instant center of motion, moment force, joint reactive force. Orthop Rev 1986;15:677–84.

34.

Bergmann

Graichen

Rohlmann

. Hip joint loading during walking and running, measured in two patients. J Biomech 1993;26:969–90.

35.

Pring

. Biomechanics of hip. In: Barret

, editor. Essential basic sciences for orthopedics. Oxford: Butterworth-Heinemann Ltd; 1994:62–93.

36.

Sommers

Roth

Hall

Kam

Ehmke

Krieg

. A laboratory model to evaluate cutout resistance of implants for pertrochanteric fracture fixation. J Orthop Trauma 2004;18:361–8.

37.

Bramlet

Wheeler

. Biomechanical evaluation of a new type of hip compression screw with retractable talons. J Orthop Trauma 2003;17:618–24.

38.

Mainds

Newman

. Implant failures in patients with proximal fractures of the femur treated with a sliding screw device. Injury 1989;20:98–100.

39.

Fogagnolo

Kfuri

Jr Paccola

. Intramedullary fixation of pertrochanteric hip fractures with the short AO-ASIF proximal femoral nail. Arch Orthop Trauma Surg 2004;124:31–7.

40.

Hesse

Gachter

. Complications following the treatment of trochanteric fractures with the gamma nail. Arch Orthop Trauma Surg 2004;124:692–8.

41.

Kregor

Obremskey

Kreder

Swiontkowski

; Evidence-Based Orthopaedic Trauma Working Group. Unstable pertrochanteric femoral fractures. J Orthop Trauma 2005;19:63–6.

42.

Dunn

Skinner

. Disengagement of a sliding screw-plate. Case report. J Bone Joint Surg Am 1976;58:1027–8.