SLIDING HIP SCREW FIXATION FOR PROXIMAL FEMUR FRACTURES

SLIDING HIP SCREW FIXATION FOR PROXIMAL FEMUR FRACTURES: AN ANALYSIS OF THE PREDICTIVE FACTORS OF FAILURE Dr Tao Shan Lim MBBS Grad Dip Surg Anat Mr Karl Stoffel MD Dr Rochelle Nicholls Ph. D Dr Bianca Billik MBBS Fremantle Orthopaedic Unit Fremantle Hospital Western Australia

The Sliding Hip Screw Trochanteric region #’s Maximises healing potential Elderly / co-morbidities

Failure 8 – 23% Bone quality Fragment geometry Reduction Implant placement Kaufer, Clinical Orthopaedics 1980, Jan-Feb: 53– 61. Dodds & Baumgaertner, Current Opinion in Orthopedics 2004, Feb: 12 -17

Baumgaertner, 1995 Tip – Apex Distance > 25 mm 19 failures in 198 fractures (9. 6%) – 16 cut out Baumgaertner et al, J Bone Joint Surg Am. 1995 Jul; 77(7): 1058 -64

Baumgaertner, 1995 Tip – Apex Distance > 25 mm 19 failures in 198 fractures (9. 6%) – 16 cut out 5 different devices – 142 sliding hip screw (3 manufacturers) – 56 intramedullary nail (2 manufacturers) Baumgaertner et al, J Bone Joint Surg Am. 1995 Jul; 77(7): 1058 -64

Study Aims Local experience of use – Dynamic Hip Screw – Exclusive use since March 2001 Identify failures Identify predictive factors

Study Design Retrospective radiological audit 731 cases 701 patients 2002 – 2004

Inclusion Criteria New adult proximal femur fracture Adequate imaging – Preoperative – Implant

Methods Theatre database Ortho techs PACS Revision – Cause

PACS Picture Archiving Computer System Fremantle Hospital – 2001 Sir Charles Gairdner Hospital – 2004 Royal Perth Hospital – 2004

Fracture Classification AO / Muller Evan’s Müller et al; Manual of internal fixation: techniques recommended by the AO-ASIF group, ed 3, Berlin, 1991, Springer-Verlag

Fracture Classification AO / Muller Evan’s Evan E. J Bone Joint Surg 1949; 31 B: 190– 203

X-rays 1. Reduction Alignment AP Normal or slight valgus Alignment Lateral Less than 20 degrees tilt of femoral head

X-rays 1. Reduction Displacement Less than 5 mm displacement of any bone fragment

X-rays 1. Reduction 2. Tip – Apex Distance Baumgaertner et al, J Bone Joint Surg Am. 1995 Jul; 77(7): 1058 -64

X-rays 1. Reduction 2. Tip – Apex Distance 3. Position of screw in femoral head Cleveland et al, J Bone Joint Surg Am. 1959 Dec; 41 -A: 1399 -408

Exclusion Criteria Not a fracture – 1 case (myeloma) Inadequate imaging – 11 cases

Demographics 387 Females, 120 Males – Female : Male 2. 79 : 1 Mean age 80. 9 years – Range 15. 0 – 106. 2 – SD 13. 0

Age

ASA Score

Radiological Follow Up Intraoperative only 25. 3% Postoperative X-ray within 2 weeks 33. 8% X-ray between 2 weeks and 3 months 17. 9% X-ray after 3 months 23. 0%

Surgeon Consultant 10. 7% 41 min Fellow 1. 8% 43 min Training registrar 50. 6% 39 min Service registrar 36. 9% 50 min

Surgeon Consultant 10. 7% 41 min Fellow 1. 8% 43 min Training registrar 50. 6% 39 min 36. 9% 50 min P < 0. 001 Service registrar

Fracture Region 22. 4% N = 164 76. 3% N = 407 1. 2% N=9

Trochanter vs Neck Age (years) ASA Contralateral #NOF 82. 7 2. 85 11. 5% 75. 1 2. 52 6. 7%

AO / Muller Classification 266 46. 9% N=9 235 57 41. 4% 10. 1% N=9

AO / Muller Classification 266 46. 9% N=9 235 57 41. 4% 10. 1% N=9

AO / Muller Classification 266 46. 9% N=9 235 57 41. 4% 10. 1% N=9

Evan’s Classification 73. 7% N = 418 26. 3% N = 149

Reduction Good 336 59. 3% Acceptable 125 22. 0% Poor 106 18. 7%

Cleveland Zone

Tip – Apex Distance Mean 20 mm – Range 5 to 44 – SD 6. 1 Stable ≈ unstable – 20 vs 22 mm

Tip – Apex Distance

Failures 14 revisions - 2. 5% – In 567 cases! 10 cut out – Superior breach of femoral head 4 failures of plate screws – “Reverse cut out”

Failures 14 revisions - 2. 5% – In 567 cases! 10 cut out – Superior breach of femoral head 4 failures of plate screws – “Reverse cut out”

Failures 14 revisions - 2. 5% – In 567 cases! 10 cut out – Superior breach of femoral head 4 failures of plate screws – “Reverse cut out”

Cut Out - TAD P < 0. 001

Cut Out - TAD Cut Out TAD < 25 TAD ≥ 25 Yes 0 10 No 437 120 Total 0% 7. 7%

Cut Out Evan’s Unstable – 10 of 10 Displacement > 4 mm – 10 of 10 Varus reduction – 8 of 10

Cut Out – Cleveland Zone

Cut Out – Cleveland Zone

Cut Out – Cleveland Zone

Cut Out – Cleveland Zone

Bivariate Regression Rank Variable P value 1 Tip-Apex Distance 1. 86 x 10 -8 2 Evan’s Unstable 9. 10 x 10 -8 3 Poor Reduction 5. 25 x 10 -7 4 Inferior Posterior Hip Screw 9. 85 x 10 -6 5 Superior Anterior Hip Screw 3. 11 x 10 -5

Multivariate Regression Rank Variable P value 1 Tip-Apex Distance 1. 58 x 10 -6 2 Evan’s Unstable 4. 30 x 10 -3 3 Poor Reduction 6. 21 x 10 -1

Failure Rate of 2. 5%? Choice of implant – Less unstable Quality of results – Mean TAD 20 mm (Baumgaertner 25 mm) Computerised PACS – Statewide tertiary catchment

Failure Rate of 2. 5%?

Failure Rate of 2. 5%? Choice of implant – Less unstable Quality of results – Mean TAD 20 mm (Baumgaertner 25 mm) Computerised PACS – Statewide tertiary catchment

Failure Rate of 2. 5%? Choice of implant – Less unstable Quality of results – Mean TAD 20 mm (Baumgaertner 25 mm) Computerised PACS – Statewide tertiary catchment

Study Weaknesses Level IV evidence Observer bias Loss of failures to the private sector ? X-rays on clinical need

Summary Accurate reflection of experience Captures all complications and revisions in Western Australian tertiary centres

Acknowledgements Synthes Australia – Ben Fraser FH, SCGH, RPH Orthopaedic Technicians – Particularly Steve and Ken from Fremantle My wife May – Data entry!

Insurance Status Insurance N % HO 591 80. 8% VA 80 10. 9% PI 38 5. 2% MV 14 1. 9% OV 6 0. 8% WC 2 0. 3%

Plate Length N % 2 hole 15 2. 6% 4 hole 522 92. 1% 5 hole 16 2. 8% 6 hole 11 1. 9% 8 hole 2 0. 4% 12 hole 1 0. 2%

Plate Angle N % 130 deg 122 21. 5% 135 deg 386 68. 1% 140 deg 46 8. 1% 145 deg 10 1. 8% 150 deg 3 0. 5%

DHS Extras Implant N % Trochanteric Side Plate 12 2. 1% Antirotation Screw 7 1. 2%