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The effect of the intramedullary canal diameter on interfragmentary movement in diaphyseal tibia fractures after reamed intramedullary nailing—A Cadaveric study
Injury 42 (2011) 972–974
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Abstracts from the 2011 Meeting of the British Trauma Society, 4th – 6th May 2011
The following three abstracts (1st prize: 2B.14; 2nd prize: 2B.19; 3rd prize: 2B.17), presented during the 2011 Annual Meeting of the British Trauma Society were the winners of the Injury Journal Awards. 2B.14 Using the medial malleolus as a guide when aiming the drill for placement of a syndesmosis screw. A CT evaluation of 100 normal ankles to find what area of the medial malleolus to aim for M.T. Kennedy 1 , S. Leong 1 , A. Mitra 1 , L. Spence 2 , M. Dolan 1 1
Department of Orthopaedic and Trauma Surgery, Cork University Hospital, Wilton, Cork City, Ireland 2 Department of Radiology, Cork University Hospital, Wilton, Cork City, Ireland The purpose of the study was to elucidate the ideal syndesmosis drill hole direction that would not displace the fibula relative to the tibia at 20 mm proximal to the ankle joint. Classical AO teaching recommends that a syndesmosis screw should be inserted at 30◦ angle to the horizontal plane of the ankle. In practice accurately judging the 30◦ angle can be difficult, and there are several reports based on post operative CT scans demonstrating that a significant minority of patients have poorly operatively reduced syndedmosis injuries. The CT scans of 100 normal ankles which had been performed as part a CT angiogram were retrospectively examined. The centroid of the fibula and tibia in the axial plane 20 mm proximal to the talar dome was calculated. Since a force vector between the centroid of the fibula and the tibia in the axial plane should not displace the fibula relative to the tibia, a line connecting the two centroids was therefore postulated to be the ideal syndesmosis line. Where this ideal line passed through the postero-lateral border of the fibula, and through the medial malleolus was then noted. The ideal syndesmosis line was shown to pass through the fibula with in 2 mm of the postero-lateral cortical apex of the fibula, and the anterior half of the medial malleolus in 100% of the ankles studied. The measurements also demonstrate that there is no statistical or clinical difference between the syndesmosis measurements of left and right ankles in the same patient. The results support the concept that in the operatively reduced syndesmosis, the anterior half of the medial malleolus can be used as a reliable guide for aiming the syndesmosis drill hole, provided
0020-1383/$ – see front matter
that the fibular entry point is at or adjacent the posterior fibular apex. The measurement data also validates the efficacy of obtaining CT images of the contralateral normal ankle when trying to ascertain if a syndesmosis is malreduced. doi:10.1016/j.injury.2011.06.183 2B.19 The effect of the intramedullary canal diameter on interfragmentary movement in diaphyseal tibia fractures after reamed intramedullary nailing—A Cadaveric study J.G. Galbraith 1,2 , H.L. Dailey 2 , C. Daly 2 , M. Cronin 3 , M. Breen 4 , J.A. Harty 1 1 Department of Trauma and Orthopaedic Surgery, Cork University Hospital, Cork, Ireland 2 Department of Mechanical Engineering, Cork Institute of Technology, Cork, Ireland 3 Department of Anatomy, University College Cork, Cork, Ireland 4 Department of Radiology, Cork University Hospital, Cork, Ireland
Introduction: The value of dynamisation of statically locked intramedullary (IM) nails in the treatment of delayed-union of the tibia has been poorly documented. Many authors report no effect on the speed of fracture union. We performed a biomechanical study using cadaveric bones to measure the forces required to compress and distract the interfragmentary gap in a tibial shaft fracture model fixed by IM nailing in dynamisation mode. We also measured interfragmentary movements that occur under physiological loading conditions with the IM nails statically locked. Methods: Eight human cadaveric tibiae were tested. Interfragmentary movements were measured in osteotomised specimens fixed with statically locked IM nails using axial forces to simulate full weight-bearing and toe tapping. The nails were then dynamised and the forces required to compress and distract the interfragmentary gap were measured. The diameter of each reamed intramedullary canal was measured using computed tomography (CT). Results: The forces required to compress and distract the fracture gap after dynamisation were small (range 0.88–1.88 kgf). When statically locked the interfragmentary movements under full weight-bearing forces were 0.8–1.45 mm and under toe-tapping forces were 0.11–0.3 mm. CT scans demonstrated variable measurements of the diameter in the intramedullary canal which did
Abstracts / Injury 42 (2011) 972–974
not match the selected reamer diameter. There was a strong negative correlation between clearance of the nail within the IM canal and force required for distraction. Conclusions: The forces required to distract the fracture gap were small after dynamisation. This was related to clearance of the nail within the IM canal. We attributed the variety in size of the IM canal to toggle of the reamer during the reaming process. This resulted in difficulty achieving an interference fit. This is a possible contributory factor in the poor outcomes seen in many studies after dynamisation. doi:10.1016/j.injury.2011.06.184 2B.17 The biocompatibility of acellular xenogenic scaffolds for biological cartilage repair J.F. Davies 1,2 , S. Wilshaw 2 , D. Shaw 1 , E. Ingham 2 , Z. Jin 2 , J. Fisher 2 1
Bradford Teaching Hospitals NHS Foundation Trust, United Kingdom Institute of Medical and Biological Engineering Leeds University, United Kingdom 2
Purpose: To assess whether acellular porcine derived xenogenic osteochondral grafts are non-cytotoxic to cells and therefore capable of allowing cellular in-growth and proliferation. A natural acellular scaffold may provide advantages over synthetic grafts in having pre-fabricated extra-cellular matrix which more closely recreates the normal cellular micro-environment. Methods: Two cell lines were used: Baby hamster kidney (BHK) cells and 3T3 fibroblast cells. Acellular scaffolds were produced by a decellularisation protocol using one wash (DC1) or 6 repeated washes (DC6) in sodium dodecyl sulphate (SDS) 0.1% (v/v) in hypotonic Tris buffer. Fresh osteochondral xenografts were used for comparison. Contact inhibition tests were undertaken with cell suspensions added to the grafts and controls. For extract cytotoxicity studies, a cell suspension was added to an extract of the graft to determine if there were any leachable soluble molecules that affected cell growth. An assay of ATP content was used to determine cell viability for the extract cytotoxicity studies. Results: Contact cytotoxicity studies did not show any inhibition in the growth of cells on fresh or acellular scaffolds. However, extract studies showed there was a significant reduction in the ATP content of 3T3 cells grown with extracts from grafts subjected to six washes, DC6, as well as fresh cartilage, compared to DC1 acellular scaffolds (p < 0.05). For BHK cells, a significant reduction in ATP content was found between extracts from fresh cartilage samples compared to DC1 and medium alone (p < 0.05). Conclusions: A decellularisation protocol of 6 alternating SDS washes for the DC6 acellular scaffold causes accumulation of SDS in the graft which was cytotoxic to 3T3 cells. DC1 scaffolds were biocompatible and suitable for further in vitro cell culture work. doi:10.1016/j.injury.2011.06.185
973
The following two abstracts were BTS podium prize winners (1st prize: 2B.9; 2nd prize: 2B.10). 2B.9 The road to a novel patient centred recovery scale: A qualitative approach to recovery after open tibial fracture R.W. Trickett 1 , P. Price 2 , I. Pallister 1 1 2
Morriston Hospital, Swansea, UK Cardiff University, Cardiff, UK
The aim of this study is to describe how patients perceive their recovery following open tibial fractures using a phenomenological approach. Ten adult patients with a diagnosis of “healed” open tibial fracture were recruited after completion of their surgical treatment at Morriston Hospital. All patients were between 6 months and 1 year post-injury. A purposive sampling method was employed to ensure that a range of injuries as well as clinical outcomes were included. All patients underwent an in-depth semi-structured interview, exploring all aspects of their injury, treatment, rehabilitation, psycho-social and financial situations. Interviews were completed with 2 interviewers present and continued until thematic saturation had been completed. Interview transcripts were analysed independently and then in the setting of a discussion forum by 4 researchers in order to identify themes. A number of predictable themes associated with the process of recovery emerged. “Pain” and “mobility” were understandably described by all patients as critical factors marking their recovery. Whilst pain itself was a recurrent theme, a distinct theme of “ache” was separately described. A novel and unexpected theme to emerge was “fear”. This seemed to parallel the patients ultimate recovery, with absence of fear (of further injury, complications or financial problems) seemingly marking an important point in the recovery. Adults recovering from open tibial fractures experience a wide range of emotions during their treatment and rehabilitation. Despite making a good clinical recovery, few patients describe themselves as having fully recovered. The themes identified in this study will be used to generate appropriate items for the first steps in the development of a novel scale to measure recovery in patients with severe lower limb trauma. doi:10.1016/j.injury.2011.06.186 2B.10 Managing paediatric forearm fractures, a little effort from the surgeon makes a lot of difference: The Brighton experience A. Baskaradas, A. Keightley, R. Vaidyalinga Sharma Brighton & Sussex University Hospital, United Kingdom Study Aims: An audit to change practice and decrease the remanipulation rate of paediatric forearm fractures. Background: Forearm fractures represent approximately 20 – 30% of all fractures in children. Re-displacement or re-angulation is the most commonly reported complication in fractures treated in plaster and invariably needs re-manipulation. Methods: Data was collated from theatre lists for forearm fractures treated with MUA and plaster under anaesthesia over an initial 18 month period. Radiographic analysis of bony alignment both pre/post-manipulation was then performed. The gap index and cast index were calculated on radiographic assessment by an orthopaedic registrar. Results: Results of the initial audit of 114 fractures treated between January 2008 and July 2009 showed an overall remanipu-
Contents lists available at ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Abstracts from the 2011 Meeting of the British Trauma Society, 4th – 6th May 2011
The following three abstracts (1st prize: 2B.14; 2nd prize: 2B.19; 3rd prize: 2B.17), presented during the 2011 Annual Meeting of the British Trauma Society were the winners of the Injury Journal Awards. 2B.14 Using the medial malleolus as a guide when aiming the drill for placement of a syndesmosis screw. A CT evaluation of 100 normal ankles to find what area of the medial malleolus to aim for M.T. Kennedy 1 , S. Leong 1 , A. Mitra 1 , L. Spence 2 , M. Dolan 1 1
Department of Orthopaedic and Trauma Surgery, Cork University Hospital, Wilton, Cork City, Ireland 2 Department of Radiology, Cork University Hospital, Wilton, Cork City, Ireland The purpose of the study was to elucidate the ideal syndesmosis drill hole direction that would not displace the fibula relative to the tibia at 20 mm proximal to the ankle joint. Classical AO teaching recommends that a syndesmosis screw should be inserted at 30◦ angle to the horizontal plane of the ankle. In practice accurately judging the 30◦ angle can be difficult, and there are several reports based on post operative CT scans demonstrating that a significant minority of patients have poorly operatively reduced syndedmosis injuries. The CT scans of 100 normal ankles which had been performed as part a CT angiogram were retrospectively examined. The centroid of the fibula and tibia in the axial plane 20 mm proximal to the talar dome was calculated. Since a force vector between the centroid of the fibula and the tibia in the axial plane should not displace the fibula relative to the tibia, a line connecting the two centroids was therefore postulated to be the ideal syndesmosis line. Where this ideal line passed through the postero-lateral border of the fibula, and through the medial malleolus was then noted. The ideal syndesmosis line was shown to pass through the fibula with in 2 mm of the postero-lateral cortical apex of the fibula, and the anterior half of the medial malleolus in 100% of the ankles studied. The measurements also demonstrate that there is no statistical or clinical difference between the syndesmosis measurements of left and right ankles in the same patient. The results support the concept that in the operatively reduced syndesmosis, the anterior half of the medial malleolus can be used as a reliable guide for aiming the syndesmosis drill hole, provided
0020-1383/$ – see front matter
that the fibular entry point is at or adjacent the posterior fibular apex. The measurement data also validates the efficacy of obtaining CT images of the contralateral normal ankle when trying to ascertain if a syndesmosis is malreduced. doi:10.1016/j.injury.2011.06.183 2B.19 The effect of the intramedullary canal diameter on interfragmentary movement in diaphyseal tibia fractures after reamed intramedullary nailing—A Cadaveric study J.G. Galbraith 1,2 , H.L. Dailey 2 , C. Daly 2 , M. Cronin 3 , M. Breen 4 , J.A. Harty 1 1 Department of Trauma and Orthopaedic Surgery, Cork University Hospital, Cork, Ireland 2 Department of Mechanical Engineering, Cork Institute of Technology, Cork, Ireland 3 Department of Anatomy, University College Cork, Cork, Ireland 4 Department of Radiology, Cork University Hospital, Cork, Ireland
Introduction: The value of dynamisation of statically locked intramedullary (IM) nails in the treatment of delayed-union of the tibia has been poorly documented. Many authors report no effect on the speed of fracture union. We performed a biomechanical study using cadaveric bones to measure the forces required to compress and distract the interfragmentary gap in a tibial shaft fracture model fixed by IM nailing in dynamisation mode. We also measured interfragmentary movements that occur under physiological loading conditions with the IM nails statically locked. Methods: Eight human cadaveric tibiae were tested. Interfragmentary movements were measured in osteotomised specimens fixed with statically locked IM nails using axial forces to simulate full weight-bearing and toe tapping. The nails were then dynamised and the forces required to compress and distract the interfragmentary gap were measured. The diameter of each reamed intramedullary canal was measured using computed tomography (CT). Results: The forces required to compress and distract the fracture gap after dynamisation were small (range 0.88–1.88 kgf). When statically locked the interfragmentary movements under full weight-bearing forces were 0.8–1.45 mm and under toe-tapping forces were 0.11–0.3 mm. CT scans demonstrated variable measurements of the diameter in the intramedullary canal which did
Abstracts / Injury 42 (2011) 972–974
not match the selected reamer diameter. There was a strong negative correlation between clearance of the nail within the IM canal and force required for distraction. Conclusions: The forces required to distract the fracture gap were small after dynamisation. This was related to clearance of the nail within the IM canal. We attributed the variety in size of the IM canal to toggle of the reamer during the reaming process. This resulted in difficulty achieving an interference fit. This is a possible contributory factor in the poor outcomes seen in many studies after dynamisation. doi:10.1016/j.injury.2011.06.184 2B.17 The biocompatibility of acellular xenogenic scaffolds for biological cartilage repair J.F. Davies 1,2 , S. Wilshaw 2 , D. Shaw 1 , E. Ingham 2 , Z. Jin 2 , J. Fisher 2 1
Bradford Teaching Hospitals NHS Foundation Trust, United Kingdom Institute of Medical and Biological Engineering Leeds University, United Kingdom 2
Purpose: To assess whether acellular porcine derived xenogenic osteochondral grafts are non-cytotoxic to cells and therefore capable of allowing cellular in-growth and proliferation. A natural acellular scaffold may provide advantages over synthetic grafts in having pre-fabricated extra-cellular matrix which more closely recreates the normal cellular micro-environment. Methods: Two cell lines were used: Baby hamster kidney (BHK) cells and 3T3 fibroblast cells. Acellular scaffolds were produced by a decellularisation protocol using one wash (DC1) or 6 repeated washes (DC6) in sodium dodecyl sulphate (SDS) 0.1% (v/v) in hypotonic Tris buffer. Fresh osteochondral xenografts were used for comparison. Contact inhibition tests were undertaken with cell suspensions added to the grafts and controls. For extract cytotoxicity studies, a cell suspension was added to an extract of the graft to determine if there were any leachable soluble molecules that affected cell growth. An assay of ATP content was used to determine cell viability for the extract cytotoxicity studies. Results: Contact cytotoxicity studies did not show any inhibition in the growth of cells on fresh or acellular scaffolds. However, extract studies showed there was a significant reduction in the ATP content of 3T3 cells grown with extracts from grafts subjected to six washes, DC6, as well as fresh cartilage, compared to DC1 acellular scaffolds (p < 0.05). For BHK cells, a significant reduction in ATP content was found between extracts from fresh cartilage samples compared to DC1 and medium alone (p < 0.05). Conclusions: A decellularisation protocol of 6 alternating SDS washes for the DC6 acellular scaffold causes accumulation of SDS in the graft which was cytotoxic to 3T3 cells. DC1 scaffolds were biocompatible and suitable for further in vitro cell culture work. doi:10.1016/j.injury.2011.06.185
973
The following two abstracts were BTS podium prize winners (1st prize: 2B.9; 2nd prize: 2B.10). 2B.9 The road to a novel patient centred recovery scale: A qualitative approach to recovery after open tibial fracture R.W. Trickett 1 , P. Price 2 , I. Pallister 1 1 2
Morriston Hospital, Swansea, UK Cardiff University, Cardiff, UK
The aim of this study is to describe how patients perceive their recovery following open tibial fractures using a phenomenological approach. Ten adult patients with a diagnosis of “healed” open tibial fracture were recruited after completion of their surgical treatment at Morriston Hospital. All patients were between 6 months and 1 year post-injury. A purposive sampling method was employed to ensure that a range of injuries as well as clinical outcomes were included. All patients underwent an in-depth semi-structured interview, exploring all aspects of their injury, treatment, rehabilitation, psycho-social and financial situations. Interviews were completed with 2 interviewers present and continued until thematic saturation had been completed. Interview transcripts were analysed independently and then in the setting of a discussion forum by 4 researchers in order to identify themes. A number of predictable themes associated with the process of recovery emerged. “Pain” and “mobility” were understandably described by all patients as critical factors marking their recovery. Whilst pain itself was a recurrent theme, a distinct theme of “ache” was separately described. A novel and unexpected theme to emerge was “fear”. This seemed to parallel the patients ultimate recovery, with absence of fear (of further injury, complications or financial problems) seemingly marking an important point in the recovery. Adults recovering from open tibial fractures experience a wide range of emotions during their treatment and rehabilitation. Despite making a good clinical recovery, few patients describe themselves as having fully recovered. The themes identified in this study will be used to generate appropriate items for the first steps in the development of a novel scale to measure recovery in patients with severe lower limb trauma. doi:10.1016/j.injury.2011.06.186 2B.10 Managing paediatric forearm fractures, a little effort from the surgeon makes a lot of difference: The Brighton experience A. Baskaradas, A. Keightley, R. Vaidyalinga Sharma Brighton & Sussex University Hospital, United Kingdom Study Aims: An audit to change practice and decrease the remanipulation rate of paediatric forearm fractures. Background: Forearm fractures represent approximately 20 – 30% of all fractures in children. Re-displacement or re-angulation is the most commonly reported complication in fractures treated in plaster and invariably needs re-manipulation. Methods: Data was collated from theatre lists for forearm fractures treated with MUA and plaster under anaesthesia over an initial 18 month period. Radiographic analysis of bony alignment both pre/post-manipulation was then performed. The gap index and cast index were calculated on radiographic assessment by an orthopaedic registrar. Results: Results of the initial audit of 114 fractures treated between January 2008 and July 2009 showed an overall remanipu-