Session 12: Yoda Best Papers
19. November
13:30 - 15:00
Lokale: 102-103
Jonas Adjal*, Asger Haugaard*+, Liv Vesterby*, Huda Ibrahim Muhudin^, Kevser Sert^, Morten Grove Thomsen*, Peter Toft Tengberg*, Ilija Ban*, Søren Ohrt-Nissen*+
* Department of Orthopaedic Surgery and Traumatology, Hvidovre Hospital, CORH, Denmark + Department of Orthopaedic Surgery and Traumatology, Køge Hospital, Sjællands Universitetshospital, Denmark ^ Danmarks Tekniske Universitet, DTU, Technical University of Denmark, MEK - Department of Mechanical Engineering, Denmark.
Background: Transverse patella fractures are traditionally treated with metallic tension band, which is associated with high reoperation rates due to implant failure, infection, and most of all implant prominence. Non-metallic techniques could be a viable alternative.
Aim: To assess whether strength of fixation of transverse patella fractures using a non- metallic all suture-based technique applied only in soft tissue is comparable to traditional metallic tension band.
Materials and Methods: Twenty paired human cadaveric specimens were included. A transverse fracture was created, reduced and fixated using either a standardized non-metallic or metallic technique in a pairwise random fashion. Metallic fixation was done according to the AO description of modified anterior tension band wiring with k-wires. Specimens were fixed in 90 degrees of flexion and underwent 200 cycles of loading in a MTS® apparatus by pulling the Quadriceps tendon to 300 Newton. Fracture displacement was optically monitored using digital image correlation. Primary outcome was mean fracture displacement after 200 cycles compared to the first cycle. Subsequently, load-to-failure was assessed by a monotonic pull to 1000 N. Failure was defined as a drop in the force measured by the force transducer.
Results: For cyclic loading analysis, one specimen from each group was excluded due to technical difficulties with the DIC. Median (min-max) fracture displacement was 0.65 mm (0.06-1.3) in the non-metallic group (p=0.931) and 0.68 mm (0-1.23) in the metallic group. No difference in displacement was found between the two groups in the repeated measures analysis of variance (p=0.5524). For load-to- failure analysis one specimen was excluded. 2/9 specimens failed in the non-metallic group (at 979 and 635 N) and 2/10 failed in the metallic group (745 and 654 N).
Interpretation / Conclusion: Non-metallic and metallic techniques showed similar strength of fixation during both cyclic and failure loading. We conclude that the non- metallic technique biomechanically is a viable alternative to traditional tension band fixation. Non-metallic techniques may have fewer implant-related complications, which we suggest as a focus for future studies.
* Department of Orthopaedic Surgery and Traumatology, Hvidovre Hospital, CORH, Denmark + Department of Orthopaedic Surgery and Traumatology, Køge Hospital, Sjællands Universitetshospital, Denmark ^ Danmarks Tekniske Universitet, DTU, Technical University of Denmark, MEK - Department of Mechanical Engineering, Denmark.
Background: Transverse patella fractures are traditionally treated with metallic tension band, which is associated with high reoperation rates due to implant failure, infection, and most of all implant prominence. Non-metallic techniques could be a viable alternative.
Aim: To assess whether strength of fixation of transverse patella fractures using a non- metallic all suture-based technique applied only in soft tissue is comparable to traditional metallic tension band.
Materials and Methods: Twenty paired human cadaveric specimens were included. A transverse fracture was created, reduced and fixated using either a standardized non-metallic or metallic technique in a pairwise random fashion. Metallic fixation was done according to the AO description of modified anterior tension band wiring with k-wires. Specimens were fixed in 90 degrees of flexion and underwent 200 cycles of loading in a MTS® apparatus by pulling the Quadriceps tendon to 300 Newton. Fracture displacement was optically monitored using digital image correlation. Primary outcome was mean fracture displacement after 200 cycles compared to the first cycle. Subsequently, load-to-failure was assessed by a monotonic pull to 1000 N. Failure was defined as a drop in the force measured by the force transducer.
Results: For cyclic loading analysis, one specimen from each group was excluded due to technical difficulties with the DIC. Median (min-max) fracture displacement was 0.65 mm (0.06-1.3) in the non-metallic group (p=0.931) and 0.68 mm (0-1.23) in the metallic group. No difference in displacement was found between the two groups in the repeated measures analysis of variance (p=0.5524). For load-to- failure analysis one specimen was excluded. 2/9 specimens failed in the non-metallic group (at 979 and 635 N) and 2/10 failed in the metallic group (745 and 654 N).
Interpretation / Conclusion: Non-metallic and metallic techniques showed similar strength of fixation during both cyclic and failure loading. We conclude that the non- metallic technique biomechanically is a viable alternative to traditional tension band fixation. Non-metallic techniques may have fewer implant-related complications, which we suggest as a focus for future studies.
Sara K. Tøstesen, Pelle Hanberg, Mats Bue, Theis M. Thillemann, Thomas Falstie-Jensen, Mikkel Tøttrup, Martin B. Knudsen, Maiken Stilling
Institute of Clinical Medicine, Aarhus University Hospital; Aarhus Microdialysis Research Group, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital; Department of Orthopedic Surgery, Aalborg University Hospital; Institute of Clinical Medicine, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital
Background: In orthopedic surgery, perioperative antibiotic prophylaxis is a key element in the prevention of surgical site infections (SSI). For the majority of procedures, antibiotic administration follows fixed dosing regimens irrespective of weight. Obese patients (BMI =30 kg/m2) have higher risk of SSI’s, which may be attributed to insufficient antibiotic target tissue concentrations.
Aim: To investigate the effect of weight-based cefuroxime dosing on plasma and target tissue concentrations relevant for orthopedic surgery; bone, skeletal muscle and subcutaneous tissue.
Materials and Methods: Eighteen female pigs were included and randomized to three study groups of six pigs differentiated by weight: Group 1: 53-57 kg, Group 2: 73-77 kg, and Group 3: 93-97 kg. Microdialysis catheters were placed for sampling in cancellous bone (scapular neck), deltoid muscle and surgical site subcutaneous tissue. Blood samples were drawn from a central venous catheter. Cefuroxime was dosed according to weight (20 mg/kg) and administered intravenously as one bolus. Continuous sampling was performed during 8 hours from cefuroxime infusion. Cefuroxime concentrations were quantified using chromatography. The primary endpoint was time above cefuroxime clinical breakpoint minimal inhibitory concentration for Staphylococcus aureus (T>MIC (4 µg/mL)).
Results: Similar T>MIC (4 µg/mL) in all target tissues were found between groups. Mean T>MIC (4 µg/mL) ranged between 116-137 min (plasma), 118-154 min (bone), 109-146 min (skeletal muscle), and 117-165 min (subcutaneous tissue) across the three groups. A mean cefuroxime concentration of 4 µg/mL was reached within 19 min in all the investigated compartments and in all groups.
Interpretation / Conclusion: Weight-adjusted (20 mg/kg) cefuroxime dosing provided comparable plasma and orthopedic target tissue T>MIC (4 µg/mL) in three different weight groups. Especially in obese patients, a weight- based cefuroxime dosing approach may optimize the perioperative target tissue exposure and potentially reduce the risk of surgical site infections.
Institute of Clinical Medicine, Aarhus University Hospital; Aarhus Microdialysis Research Group, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital; Department of Orthopedic Surgery, Aalborg University Hospital; Institute of Clinical Medicine, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital
Background: In orthopedic surgery, perioperative antibiotic prophylaxis is a key element in the prevention of surgical site infections (SSI). For the majority of procedures, antibiotic administration follows fixed dosing regimens irrespective of weight. Obese patients (BMI =30 kg/m2) have higher risk of SSI’s, which may be attributed to insufficient antibiotic target tissue concentrations.
Aim: To investigate the effect of weight-based cefuroxime dosing on plasma and target tissue concentrations relevant for orthopedic surgery; bone, skeletal muscle and subcutaneous tissue.
Materials and Methods: Eighteen female pigs were included and randomized to three study groups of six pigs differentiated by weight: Group 1: 53-57 kg, Group 2: 73-77 kg, and Group 3: 93-97 kg. Microdialysis catheters were placed for sampling in cancellous bone (scapular neck), deltoid muscle and surgical site subcutaneous tissue. Blood samples were drawn from a central venous catheter. Cefuroxime was dosed according to weight (20 mg/kg) and administered intravenously as one bolus. Continuous sampling was performed during 8 hours from cefuroxime infusion. Cefuroxime concentrations were quantified using chromatography. The primary endpoint was time above cefuroxime clinical breakpoint minimal inhibitory concentration for Staphylococcus aureus (T>MIC (4 µg/mL)).
Results: Similar T>MIC (4 µg/mL) in all target tissues were found between groups. Mean T>MIC (4 µg/mL) ranged between 116-137 min (plasma), 118-154 min (bone), 109-146 min (skeletal muscle), and 117-165 min (subcutaneous tissue) across the three groups. A mean cefuroxime concentration of 4 µg/mL was reached within 19 min in all the investigated compartments and in all groups.
Interpretation / Conclusion: Weight-adjusted (20 mg/kg) cefuroxime dosing provided comparable plasma and orthopedic target tissue T>MIC (4 µg/mL) in three different weight groups. Especially in obese patients, a weight- based cefuroxime dosing approach may optimize the perioperative target tissue exposure and potentially reduce the risk of surgical site infections.
Laura Amalie Rytoft, Markus Winther Frost, Ole Rahbek, Ming Shen, Kirsten Duch, Søren Kold
Laura Amalie Rytoft; Interdisciplinary Orthopaedics, Aalborg University Hospital Markus Winther Frost; Interdisciplinary Orthopaedics, Aalborg University Ole Rahbek; Interdisciplinary Orthopaedics, Aalborg University Ming Shen; Dept. of Electronic Systems, Aalborg University Kirsten Duch; Dept. of Epidemiology and Biostatistics, Aalborg University Hospital Søren Kold; Interdisciplinary Orthopaedics, Aalborg University
Background: Home-based monitoring of fracture healing has the potential of reducing routine follow- up and improve personalized fracture care. Implantable sensors measuring electrical impedance might detect changes in the electrical current as the fracture heals.
Aim: The aim was to investigate whether electrical impedance correlated with radiographic fracture healing.
Materials and Methods: Eighteen rabbits were subjected to a tibial osteotomy that was stabilized with an external fixator. Two electrodes were positioned, one electrode placed within the medullary cavity and the other on the lateral cortex, both three millimeters from the osteotomy site. Transverse electrical impedance was measured daily across the fracture site at a frequency range of 5 Hz to 1 MHz using an Analog Discovery 2 Oscilloscope with Impedance Analyzer. Biweekly x- rays were taken and analyzed blinded using a modified anterior-posterior (AP) radiographic union score of the tibia (RUST). Each animal served as its own control by performing repeated measurements from time zero until the end of follow-up.
Results: At 5 Hz measurements, a linear mixed model revealed an average impedance at day zero of 10670 ± 272 Ohm (p<0.001) and a change in impedance from day 0 to day 7 of -3330± 152 (p<0.001). The slope from day 0-7 was estimated as -548.6 ±26 (p<0.001) and was steeper than the slope after day 7 which was estimated to -85.6±4 (p<0.001). This indicates that the impedance decreased quicker before day 7 and slower after day 7. The coefficient of variation for difference between RUST scores, from double intra-rater measurements of 15 radiographs with a minimum of 22 days between, was 1.3. Spearman’s correlation coefficient between impedance and RUST score at the 5 Hz was -0.75 (p<0.001).
Interpretation / Conclusion: This osteotomy model showed that the electrical impedance can be measured in vivo at a distance from the fracture site with a consistent change in impedance over time. This is the first study to demonstrate a significant correlation between increasing radiographic union score and decreasing impedance. Further studies are warranted to investigate how these new and important results can further be translated into larger animal studies.
Laura Amalie Rytoft; Interdisciplinary Orthopaedics, Aalborg University Hospital Markus Winther Frost; Interdisciplinary Orthopaedics, Aalborg University Ole Rahbek; Interdisciplinary Orthopaedics, Aalborg University Ming Shen; Dept. of Electronic Systems, Aalborg University Kirsten Duch; Dept. of Epidemiology and Biostatistics, Aalborg University Hospital Søren Kold; Interdisciplinary Orthopaedics, Aalborg University
Background: Home-based monitoring of fracture healing has the potential of reducing routine follow- up and improve personalized fracture care. Implantable sensors measuring electrical impedance might detect changes in the electrical current as the fracture heals.
Aim: The aim was to investigate whether electrical impedance correlated with radiographic fracture healing.
Materials and Methods: Eighteen rabbits were subjected to a tibial osteotomy that was stabilized with an external fixator. Two electrodes were positioned, one electrode placed within the medullary cavity and the other on the lateral cortex, both three millimeters from the osteotomy site. Transverse electrical impedance was measured daily across the fracture site at a frequency range of 5 Hz to 1 MHz using an Analog Discovery 2 Oscilloscope with Impedance Analyzer. Biweekly x- rays were taken and analyzed blinded using a modified anterior-posterior (AP) radiographic union score of the tibia (RUST). Each animal served as its own control by performing repeated measurements from time zero until the end of follow-up.
Results: At 5 Hz measurements, a linear mixed model revealed an average impedance at day zero of 10670 ± 272 Ohm (p<0.001) and a change in impedance from day 0 to day 7 of -3330± 152 (p<0.001). The slope from day 0-7 was estimated as -548.6 ±26 (p<0.001) and was steeper than the slope after day 7 which was estimated to -85.6±4 (p<0.001). This indicates that the impedance decreased quicker before day 7 and slower after day 7. The coefficient of variation for difference between RUST scores, from double intra-rater measurements of 15 radiographs with a minimum of 22 days between, was 1.3. Spearman’s correlation coefficient between impedance and RUST score at the 5 Hz was -0.75 (p<0.001).
Interpretation / Conclusion: This osteotomy model showed that the electrical impedance can be measured in vivo at a distance from the fracture site with a consistent change in impedance over time. This is the first study to demonstrate a significant correlation between increasing radiographic union score and decreasing impedance. Further studies are warranted to investigate how these new and important results can further be translated into larger animal studies.
Nana Brøndel, Jan Carstensen, Jannik Hansen, Anas Saaid, Kristoffer Borbjerg Hare
Department of Orthopedics, Næstved-Slagelse-Ringsted Hospitals, Denmark and Department of Clinical Research, University of Southern Denmark, Odense, Denmark; Department of Orthopedics, Næstved-Slagelse-Ringsted Hospitals, Denmark; (no affiliations) ; Department of Orthopedics, Næstved-Slagelse- Ringsted Hospitals, Denmark; Department of Orthopedics, Næstved-Slagelse- Ringsted Hospitals, Denmark and Department of Physiotherapy and Occupational Therapy, Næstved-Slagelse-Ringsted Hospitals, Denmark and Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
Background: Skin tears is one of the most common side effects when treating Dupuytrens’s disease (DD) with collagenase Clostridium Histolyticum. The skin tears occur when the finger is manipulated.
Aim: The purpose of this study was to examine the effects of a supplementary band-aid on the risk of skin tears for people treated with collagenase Clostridium Histolyticum for DD. Furthermore, we examined short-term effects, patient reported outcomes and adverse events.
Materials and Methods: From June 2012 to January 2017, 177 patients with DD and 237 fingers in total were treated with collagenase Clostridium Histolyticum. 108 patients received a supplementary band-aid before manipulation of the finger, and 104 did not. We compared the rate of skin tears between the two groups, as well as the effect on function, patient related outcomes, failure of treatment, adverse events, return to work, daily activities and patient satisfaction after 3 months.
Results: We found a 2.2 (CI 1.47 to 3.41, p-value <0.001) greater risk of skin tears during manipulation for patients who did not receive a supplemental band-aid. Skin tears occurred in 43.2% (CI 34.13 to 52.66) and 19.3% (CI 12.66 to 27.58) in the no band-aid and band-aid group, respectively. Furthermore, patients who received a supplementary band-aid had a better MCP joint function at the 3-month follow- up, and they returned more quickly to daily activities. There was no difference between the two groups in patient reported outcomes.
Interpretation / Conclusion: This study has shown that a supplementary band-aid can reduce the risk of skin tears in patients treated with collagenase during manipulation.
Department of Orthopedics, Næstved-Slagelse-Ringsted Hospitals, Denmark and Department of Clinical Research, University of Southern Denmark, Odense, Denmark; Department of Orthopedics, Næstved-Slagelse-Ringsted Hospitals, Denmark; (no affiliations) ; Department of Orthopedics, Næstved-Slagelse- Ringsted Hospitals, Denmark; Department of Orthopedics, Næstved-Slagelse- Ringsted Hospitals, Denmark and Department of Physiotherapy and Occupational Therapy, Næstved-Slagelse-Ringsted Hospitals, Denmark and Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
Background: Skin tears is one of the most common side effects when treating Dupuytrens’s disease (DD) with collagenase Clostridium Histolyticum. The skin tears occur when the finger is manipulated.
Aim: The purpose of this study was to examine the effects of a supplementary band-aid on the risk of skin tears for people treated with collagenase Clostridium Histolyticum for DD. Furthermore, we examined short-term effects, patient reported outcomes and adverse events.
Materials and Methods: From June 2012 to January 2017, 177 patients with DD and 237 fingers in total were treated with collagenase Clostridium Histolyticum. 108 patients received a supplementary band-aid before manipulation of the finger, and 104 did not. We compared the rate of skin tears between the two groups, as well as the effect on function, patient related outcomes, failure of treatment, adverse events, return to work, daily activities and patient satisfaction after 3 months.
Results: We found a 2.2 (CI 1.47 to 3.41, p-value <0.001) greater risk of skin tears during manipulation for patients who did not receive a supplemental band-aid. Skin tears occurred in 43.2% (CI 34.13 to 52.66) and 19.3% (CI 12.66 to 27.58) in the no band-aid and band-aid group, respectively. Furthermore, patients who received a supplementary band-aid had a better MCP joint function at the 3-month follow- up, and they returned more quickly to daily activities. There was no difference between the two groups in patient reported outcomes.
Interpretation / Conclusion: This study has shown that a supplementary band-aid can reduce the risk of skin tears in patients treated with collagenase during manipulation.
Christian Kveller, Skov Simon Toftgaard, Høy Kristian, Bünger Cody
Department of Orthopedic Surgery, Horsens Regional Hospital; Spine Section, Center for Planned Surgery, Silkeborg Regional Hospital; Spine Section, Department of Orthopedic Surgery, Aarhus University Hospital; Spine Section, Department of Orthopedic Surgery, Aarhus University Hospital
Background: Chordomas are rare slow-growing neoplasms affecting the spine from the base of the skull to the sacrum. These tumors are resistant to both chemo- and radiotherapy and situated in close proximity to radiosensitive neural structures. In theory particle therapy could remedy this based on the physical properties of the radiation.
Aim: The primary aim was to investigate the isolated clinical effects on overall survival following chordoma treatment with particle therapy versus photon radiotherapy in adults.
Materials and Methods: A systemic review of available literature was conducted in Cochrane, Medline and EMBASE and meta-analysis was performed on data from primary studies. The databases were searched from inception until December 2019. The search yielded 1118 articles of which 79 which were eligible for inclusion with a combined patient population of 4491.
Results: Our overall weighted estimate of the data suggests an advantage in treating chordomas located in skull and spine with particle therapy compared to photon radiotherapy on 5-year overall survival (81.4% vs 74.2%) and 5-year local control (70.6% vs 51.5%). A sub-analysis of particle therapy suggests carbon ion therapy to be slightly superior compared to proton therapy on 5-year overall survival (84.6% vs 79.7%) and 5-year local control (74.3% vs 68.1%).
Interpretation / Conclusion: Particle therapy allows for the safe and effective delivery of radiation doses exceeding 70 GyE (Gray equivalents), necessary to treat chordomas. It can spare surrounding tissues of up to 25 GyE, resulting in acceptable levels of radiation toxicities, while 5-year overall survival and local control is improved compared with photon-based therapies. Furthermore, carbon ion therapy appears to have improved outcomes compared to proton therapy, but this modality is not available in Denmark. There are several limitations to the study. The primary studies are retrospective, not uniform, of different timespans within nearly century, do not necessarily differentiate between various modalities, and chronological bias may be a significant confounder. As such the data is subject to significant confounders and direct comparative studies would be beneficial.
Department of Orthopedic Surgery, Horsens Regional Hospital; Spine Section, Center for Planned Surgery, Silkeborg Regional Hospital; Spine Section, Department of Orthopedic Surgery, Aarhus University Hospital; Spine Section, Department of Orthopedic Surgery, Aarhus University Hospital
Background: Chordomas are rare slow-growing neoplasms affecting the spine from the base of the skull to the sacrum. These tumors are resistant to both chemo- and radiotherapy and situated in close proximity to radiosensitive neural structures. In theory particle therapy could remedy this based on the physical properties of the radiation.
Aim: The primary aim was to investigate the isolated clinical effects on overall survival following chordoma treatment with particle therapy versus photon radiotherapy in adults.
Materials and Methods: A systemic review of available literature was conducted in Cochrane, Medline and EMBASE and meta-analysis was performed on data from primary studies. The databases were searched from inception until December 2019. The search yielded 1118 articles of which 79 which were eligible for inclusion with a combined patient population of 4491.
Results: Our overall weighted estimate of the data suggests an advantage in treating chordomas located in skull and spine with particle therapy compared to photon radiotherapy on 5-year overall survival (81.4% vs 74.2%) and 5-year local control (70.6% vs 51.5%). A sub-analysis of particle therapy suggests carbon ion therapy to be slightly superior compared to proton therapy on 5-year overall survival (84.6% vs 79.7%) and 5-year local control (74.3% vs 68.1%).
Interpretation / Conclusion: Particle therapy allows for the safe and effective delivery of radiation doses exceeding 70 GyE (Gray equivalents), necessary to treat chordomas. It can spare surrounding tissues of up to 25 GyE, resulting in acceptable levels of radiation toxicities, while 5-year overall survival and local control is improved compared with photon-based therapies. Furthermore, carbon ion therapy appears to have improved outcomes compared to proton therapy, but this modality is not available in Denmark. There are several limitations to the study. The primary studies are retrospective, not uniform, of different timespans within nearly century, do not necessarily differentiate between various modalities, and chronological bias may be a significant confounder. As such the data is subject to significant confounders and direct comparative studies would be beneficial.