Femoral head density on CT scans of patients following hip fracture fixation by expandable proximal peg or dynamic screw

Fractures around the hip: inducing life-like fractures as a basis for enhanced surgical training

INTRODUCTION

In this study we investigated if realistic fracture patterns around the hip can be produced on human cadaveric specimens with intact soft tissue envelope. Possible applications of such fractured specimens would be in surgical training.

MATERIALS AND METHODS

7 cadaveric specimens (2 male, 5 female, 2 formalin-fixed, 5 fresh-frozen) were fractured. 2 specimens were fractured on both femurs, 5 only on one side, resulting in 9 fractures total. 5 fractures were set in our custom-made drop-test bench, 2 fractures by inducing axial force using a hammer, and the remaining 2 fractures by a direct dorsal approach and a chisel. AO/OTA and Pauwels classification were used to classify the fractures on the specimens by two independent trauma surgeons.

RESULTS

In our drop-test bench, axial load with the femur adducted by 10° resulted in an intertrochanteric fracture (AO type A1.3), adducted by 20° resulted in a femoral neck fracture (Pauwels type III). Fracture induction using a hammer resulted in two intertrochanteric fractures (AO type A2.2 right, A3.3 left). The use of a chisel resulted in both cases in a femoral neck fracture. The acetabulum could be fractured multifragmentarily through use of a hemiprosthesis as a stamp.

CONCLUSION

A high energetic impulse induced by a custom-made drop-test bench can successfully simulate realistic proximal femur and acetabular fractures in cadaveric specimens with intact soft tissue. Furthermore, axial load using a hammer as well as using a chisel through a direct dorsal approach represent additional methods for fracture induction. These pre-fractured specimens can be utilized in surgical education to provide a realistic teaching experience for specialized trauma education courses.

Opportunistic Use of CT Imaging for Osteoporosis Screening and Bone Density Assessment: A Qualitative Systematic Review

BACKGROUND

The purpose of this study was to determine the clinical opportunities for the use of computed tomography (CT) imaging for inferring bone quality and to critically analyze the correlation between dual x-ray absorptiometry (DXA) and diagnostic CT as reported in the literature.

METHODS

A systematic review of the MEDLINE database was performed in February 2016 using the PubMed interface. The inclusion criteria were English language, studies performed using living human subjects, studies pertaining to orthopaedics, use of conventional diagnostic CT scans, studies that measured cancellous bone, and studies that reported Hounsfield unit (HU) measurements directly rather than a computed bone mineral density.

RESULTS

Thirty-seven studies that reported on a total of 9,109 patients were included. Of these, 10 studies correlated HU measurements of trabecular bone with DXA-based bone assessment. Reported correlation coefficients ranged between 0.399 and 0.891, and 5 of the studies reported appropriate threshold HU levels for diagnosing osteoporosis or osteopenia.

CONCLUSIONS

Direct HU measurement from diagnostic CT scans has the potential to be used opportunistically for osteoporosis screening, but in its current state it is not ready for clinical implementation. There is a lack of exchangeability among different machines that limits its broad applicability. Future research efforts should focus on identifying thresholds at specific anatomic regions in high-risk patients in order to have the greatest impact on patients. However, using diagnostic CT to infer region-specific osteoporosis could be extraordinarily valuable to orthopaedic surgeons and primary care physicians, and merits further research.

Favorable radiographic outcomes using the expandable proximal femoral nail in the treatment of hip fractures - A randomized controlled trial

AIM

To compare the functional and radiographic results of dynamic hip screw (DHS) and expandable proximal femoral nail (EPFN) in the treatment of extracapsular hip fractures.

METHODS

A randomized controlled trial of sixty hip fracture patients. Outcomes included mortality, residency, independence, mobility, function and radiographic results at a minimum of 1 year.

RESULTS

Twenty-nine EPFN patients demonstrated fewer cases of shaft medialization or femoral offset shortening compared to the 31 DHS patients. Mortality, complications and functional outcomes were similar.

CONCLUSION

EPFN provides stable fixation of pertrochanteric hip fractures and prevents neck shortening that is commonly observed after DHS fixation.

Does bone compaction around the helical blade of a proximal femoral nail anti-rotation (PFNA) decrease the risk of cut-out?: A subject-specific computational study

Objectives

Because of the contradictory body of evidence related to the potential benefits of helical blades in trochanteric fracture fixation, we studied the effect of bone compaction resulting from the insertion of a proximal femoral nail anti-rotation (PFNA).

Methods

We developed a subject-specific computational model of a trochanteric fracture (31-A2 in the AO classification) with lack of medial support and varied the bone density to account for variability in bone properties among hip fracture patients.

Results

We show that for a bone density corresponding to 100% of the bone density of the cadaveric femur, there does not seem to be any advantage in using a PFNA with respect to the risk of blade cut-out. On the other hand, in a more osteoporotic femoral head characterised by a density corresponding to 75% of the initial bone density, local bone compaction around the helical blade provides additional bone purchase, thereby decreasing the risk of cut-out, as quantified by the volume of bone susceptible to yielding.

Conclusions

Our findings indicate benefits of using a PFNA over an intramedullary nail with a conventional lag screw and suggest that any clinical trial reporting surgical outcomes regarding the use of helical blades should include a measure of the femoral head bone density as a covariable.

Expandable proximal femoral nails versus 95° dynamic condylar screw-plates for the treatment of reverse oblique intertrochanteric fractures

The treatment of a simple (AO/OTA classification 31A3.1) reverse oblique intertrochanteric hip fracture is a challenge for the orthopaedic surgeon. The surgical options include the use of side plates with various angled leg screws or intramedullary devices. The purpose of this study was to retrospectively assess our results of treating reverse oblique fracture with an expendable proximal femoral nail (EPFN) or with a dynamic condylar screw-plate (DCS: 95°) between January 2006 and July 2009. Thirty-three patients (6 males and 27 females, mean age 78 years) met the study inclusion criteria and comprised the two study groups: 19 had been treated by EPFNs and 14 had received DCSs. They were followed for a mean of 28 months (range 6-47). Eight patients (5 EPFN and 3 DCS) died during the follow-up period from causes not related to the operation. Two ESPN patients and 5 DCS patients had malunions. Functional outcome scores showed better results in the EPFN group, but the difference was statistically significant only for the sitting subcategory (p=0.04). Based on our results and experience, we propose that the EPFN is at least as good as the DCS for treating reverse oblique fractures of the femur.