Predicting Intra-operative Periprosthetic Fracture During Uncemented Hemiarthroplasty for Intracapsular Neck of Femur FracturesHarpal Uppal, Anil Dhadwal, Ben Dean, Partha Bose, Adnan Saithna

British Trauma Society Annual Meeting 20155th November 2015

Introduction• In the UK majority of patients sustaining intracapsular neck of femur fractures are

treated with a hemiarthroplasty1

• Uncemented technique has been deemed safer as it avoids cement related complications and are associated with shorter operating times and thus favoured in frail, elderly patients with multiple co-morbidities

• Parker et al reported in 2010 that there was no statistical significance difference in mortality or post-operative medical complications2. This was later supported by the Cochrane review from the same author3

• Australian NJR revision rate is higher in uncemented prostheses4

• Current NICE guidance for management of displaced intracapsular neck of femur fractures is cemented hemiarthroplasty5

• NHFD 2013 reports that 15.8% of all hemiarthroplasties are uncemented6

Austin Moore Prosthesis• Developed in the 1950s

• Minor ammendments over the last 60 years

• Mono-bloc implant with keel

• Popular Low cost option used in many organisations including the study institution7

• Number of studies associated with increased risk of peri-prosthetic fracture8,9

AimDetermine whether simple measurements performed on plain radiographs could provide information about risk of peri-prosthetic fracture

ObjectiveThe objective of this study was to develop a simple tool to be used at the pre-operative planning stage to assess patients for the risk of intra-operative fracture

Methods• Single centre study (Alexandra Hospital, Redditch)

• 258 consecutive patients who underwent hip hemiarthroplasties identified on hospital theatre management system

• Duration of Study – 3 years

• Operation notes, patient records and plain films radiographs reviewed independently by two observers

• Fractures classified using Vancouver system10

Method of Radiological Evaluation- Sen et al11

• Magnification of radiographs

• Ratio of radiograph size and actual implant size

• Femur Canal Diameter then measured at three levels (perpendicular to shaft)– A. Upper Lesser trochanter– B. Lower lesser trochanter– C. 75mm distal to LLT

Figure 1: Plain film radiograph illustrating sites of canal measurements

Analysis• Anonymised data collection

• Other Parameters measured– Age, gender, seniority of surgeon

• Matlab7.0 software used by statistician

• Two patient cohorts– No intra-operative fractures

(Group A) vs intra-operative fracture (Group B)

• Bootstrapping and non-parametric testing

• Kolmogorov Smirnov two-sample test for comparison of the two groups– Does not make any

distributional assumptions

Results• 235 patients included

• 5.5% (13) patients suffered intra-operative fractures

• All patients were treated successfully with cerclage wires

• Grade of surgeon did not have a prognostic influence– χ2 with Yates correction = 0.11 (p=0.025)

• Sex did not have a prognostic influence– χ2 with Yates correction = 0.025 (p=0.9

79%

21%

Fig. 2 Vancouver classification of periprosthetic fractures

sustained in Group B

Vancouver AVancouver B

Figure 3a/3bHistogram(a) and Boot strap distribution (b) for Age in Cohorts A and B

Histogram demonstrates that the population does not fit a normal distribution

Average age in non-fracture group was 83 years old and 85 in fracture group

Figure 4a / 4bHistogram(a) and Boot strap distribution (b) Upper Border of Lesser Trochanter (Upper LT) measurements

Bootstrapping distribution suggests that patients with an Upper LT diameter greater than 38.5mm are at greater risk of peri-prosthetic fracture

Figure 5a/5b Lower Histogram(a) and Boot strap distribution (b) Border of Lesser Trochanter (Lesser LT) measurements

Bootstrapping distribution suggests that patients with an Lower LT diameter greater than 26mm are at greater risk of peri-prosthetic fracture

Figure 6a/6bHistogram(a) and Boot strap distribution (b) 75mm lower than Lesser Trochanter measurements

Bootstrapping distribution suggests that patients with that there is a similar distribution between Group A and Group B

Femoral diameter was increased marginally in the Group B distribution

Discussion• Osteoporosis is a major risk factor for intraoperative peri-prosthetic fracture when

using an uncemented implant

• Osteoporosis is associated not only with proximal femoral cortical thinning but also increased marrow star volume12

• Study demonstrates patients who have upper and lower LT widths of greater than 38.5 mm and 26 mm respectively are at greater risk of intra-operative fracture

• Previous literature has supported our findings using the Dorr Classification13, 14

• We provide a more quantifiable approach to risk stratification providing patient has a calibrating plain film at time of injury

• Our study does not look to advocate one implant over another

Limitations• AMH was the only hemiarthroplasty implant available at the study

centre

• The more modern uncemented stems may have different geometry and not behave in the same way

• Patients were not risk stratified with regards other recognised risk factors

• Authors still feel that the study offers a pragmatic approach as patients presenting with fragility fractures often have multiple co-morbidities

Conclusion

• Uncemented hemiarthroplasty of the hip is associated with an increased risk of peri-prosthetic fracture

• Pre-operative measurements of the femoral canal at upper and lower borders of the lesser trochanter can aid decision making

• Upper LT >38.5mm and Lower LT>26mm show statistical significance authors would recommend using a cemented implant and technique as opposed to an AMH

References1. Jameson SS, Jensen CD, Elson DW, Johnson A, Nachtsheim C, Rangan A, Muller SD, Reed MR. Cemented versus cementless hemiarthroplasty for intracapsular neck of femurfracture—A comparison of 60,848 matched patients using national data. Injury, Int. J. Care Injured 2013; 44: 730–734 2. Parker MI, Pryor G, Gurusamy K. Cemented versus uncemented hemiarthroplasty for intracapsular hip fractures: A randomised controlled trial in 400 patients. J Bone Joint Surg Br 2010; 92(1): 116-22. 3. Parker MJ, Gurusamy KS, Azegami S. Arthroplasties (with and without bonecement) for proximal femoral fractures in adults. Cochrane Database SystematicReviews 2010; 6: CD001706. 4. No-authors-listed. Australian Orthopaedic Association, National Joint ReplacementRegister 2010. Available from: https://aoanjrr.dmac.adelaide.edu.au/annual-reports-2010 [accessed 02.08.14]. 5. National Institute for Health and Clinical Effectiveness. The management of hipfracture in adults 2011. Available from: http://www.nice.org.uk/nicemedia/live/13489/54919/54919.pdf [accessed 02.08.14]. 6. No-authors-listed. National Hip Fracture Database National Report 2013.Available from: http://www.nhfd.co.uk [accessed 02.08.14]. 7. Crossman PT, Khan RJ, MacDowell A, Gardner AC, Reddy NS, Keene GS. A survey of the treatment of displaced intracapsular femoral neck fractures in the UK. Injury 2002; 33 5: 383–6. 8. McGraw IWW, Spence SC, Baird EJ, Eckhardt SM, Ayana GE. Incidence of periprosthetic fractures after hip hemiarthroplasty: Are uncemented prostheses unsafe?Injury, Int. J. Care Injured 2013; 44: 1945–1948 9. Phillips JRA, Moran CG, MAktelow ARJ. Periprosthetic fractures around hip hemiarthroplasty performed for hip fractureInjury, Int. J. Care Injured 2013; 44: 757–76210. Duncan CP, Masri BA. Fractures of the femur after hip replacement. Instr Course Lect. 1995; 44: 293–30411. Sen RK, Tripathy SK, Kumar R, Kumar A, Dhatt S, Dhillon MS, et al. Proximal femoral medullary canal diameters in Indians: correlation between anatomic, radiographic, and computed tomographic measurements. J Orthop Surg (Hong Kong). 2010; 18(2): 189-94. 12. Blain H, Chavassieux P, Portero-Muzya N, Bonnel F, Canovasc F, Chammasc M, Maury P, Delmasa PD. Cortical and trabecular bone distribution in the femoral neck in osteoporosis and osteoarthritis. Bone 2008; 43(5): Pages 862–868 13. Nash W, Harris A. The Dorr type and cortical thickness index of the proximal femur for predicting peri-operative complications during hemiarthroplasty. Journal of Orthopaedic Surgery (Hong Kong) 2014;22(1):92-95. 14. Kendrick BJ, Wilson HA, Lippett JE, McAndrew AR, Andrade AJ. Corail uncemented hemiarthroplasty with a Cathcart head for intracapsular hip fractures. Bone Joint J 2013; 95-B(11): 1538-43

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