Session 18: Cases / Technical Notes
Onsdag d. 26. oktober
17:30-18:30
Lokale: Casino Ballroom
Chairmen: Thomas Baad Hansen / Martin Gottliebsen
Sepp De Raedt, Lars Hansen, Peter Bo Jørgensen, Bjarne Mygind-Klavsen, Maiken Stilling
Research and development, Nordisk Røntgen Teknik; Orthopedic Research Unit, Department of Clinical Medicine, Aarhus University Hospital; Orthopedic Research Unit, Department of Clinical Medicine, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital; Orthopedic Research Unit, Department of Clinical Medicine, Aarhus University Hospital
Background: Dynamic radiostereometric analysis (dRSA) can track 3D in-vivo movements of bones or implants, but analysis is time consuming. Current marker based RSA (MM) requires bone markers to be inserted and traditional model based RSA (MBM) requires models to be manually matched on each radiograph. We propose a novel digitally reconstructed radiograph based method (DRR) for automated analysis of RSA recordings of the hip joint.
Purpose / Aim of Study: To evaluate precision of DRR compared with MBM (MM as gold standard).
Materials and Methods: Seven human cadaveric hips were CT- scanned and preprocessed for analysis. Tantalum beads were inserted in the femur and pelvis. dRSA images were acquired at 5 fr/sec during flexion, adduction and internal rotation. All images were analyzed by DRR, MBM and MM. Migrations were calculated with respect to MM in 6 degrees of freedom. Precision was assessed as systematic bias (mean difference) and random variation (Pitman’s test) with respect to MM as gold standard.
Findings / Results: In total 288 dRSA images were analyzed. Systematic bias for MBM and DRR with respect to MM in translations (Δ<0.018mm) and rotations (Δ<0.009°) were approximately zero and no difference between MBM and DRR (p>0.46) was found. Random variation was lower (p<0.00) in all degrees of freedom for DRR compared to MBM. For the femur translations DRR had 40% better (Δ0.07mm) precision, and for femur rotations DDR precision was 60% better (Δ0.25°) compared to MBM. For the pelvis translations DRR had 6 fold better (Δ0.40mm) precision, and for pelvis rotations DDR had 2 fold better precision (Δ0.34°) compared to MBM.
Conclusions: DRR is a novel method for analysis of dRSA and can be used clinically for kinematic based diagnostic studies. It is automated, noninvasive, not user-dependent and more precise in comparison with MBM for analysis of the hip joint.
Research and development, Nordisk Røntgen Teknik; Orthopedic Research Unit, Department of Clinical Medicine, Aarhus University Hospital; Orthopedic Research Unit, Department of Clinical Medicine, Aarhus University Hospital; Department of Orthopedic Surgery, Aarhus University Hospital; Orthopedic Research Unit, Department of Clinical Medicine, Aarhus University Hospital
Background: Dynamic radiostereometric analysis (dRSA) can track 3D in-vivo movements of bones or implants, but analysis is time consuming. Current marker based RSA (MM) requires bone markers to be inserted and traditional model based RSA (MBM) requires models to be manually matched on each radiograph. We propose a novel digitally reconstructed radiograph based method (DRR) for automated analysis of RSA recordings of the hip joint.
Purpose / Aim of Study: To evaluate precision of DRR compared with MBM (MM as gold standard).
Materials and Methods: Seven human cadaveric hips were CT- scanned and preprocessed for analysis. Tantalum beads were inserted in the femur and pelvis. dRSA images were acquired at 5 fr/sec during flexion, adduction and internal rotation. All images were analyzed by DRR, MBM and MM. Migrations were calculated with respect to MM in 6 degrees of freedom. Precision was assessed as systematic bias (mean difference) and random variation (Pitman’s test) with respect to MM as gold standard.
Findings / Results: In total 288 dRSA images were analyzed. Systematic bias for MBM and DRR with respect to MM in translations (Δ<0.018mm) and rotations (Δ<0.009°) were approximately zero and no difference between MBM and DRR (p>0.46) was found. Random variation was lower (p<0.00) in all degrees of freedom for DRR compared to MBM. For the femur translations DRR had 40% better (Δ0.07mm) precision, and for femur rotations DDR precision was 60% better (Δ0.25°) compared to MBM. For the pelvis translations DRR had 6 fold better (Δ0.40mm) precision, and for pelvis rotations DDR had 2 fold better precision (Δ0.34°) compared to MBM.
Conclusions: DRR is a novel method for analysis of dRSA and can be used clinically for kinematic based diagnostic studies. It is automated, noninvasive, not user-dependent and more precise in comparison with MBM for analysis of the hip joint.
Martin Gottliebsen, Mathias Bünger, Ole Rahbek, Bjarne Møller-Madsen
Department of Childrens Orthopaedics, Aarhus University Hospital; Department of Childrens Orthopaedics, Aarhus University Hospital; Department of Childrens Orthopaedics, Aarhus University Hospital; Department of Childrens Orthopaedics, Aarhus University Hospital
Background: Slipped Capital Femoral Epiphysis (SCFE) is a condition that affects the hips in older children and adolescents. Current treatment is primarily based on in situ fixation using a single cannulated screw. The sub capital realignment osteotomy of the neck of femur for severe SCFE is gaining increasing acceptance. Anatomical realignment is performed after surgical dislocation of the affected hip joint. The procedure carries a risk for inducing avascular necrosis of the femoral head
Purpose / Aim of Study: To present early experience with a new setup for treating severe SCFE using new techniques for osteotomies of the proximal femur at Department of Childrens Orthopaedics, Aarhus University Hospital
Materials and Methods: Two osteotomies were performed in the following cases; severe acute on chronic SCFE in a 10 year girl and severe chronic SCFE in a 12 year girl. The sub capital realignment procedure was performed in both cases as described above. Perfusion of the femoral head was documented by either SPECT scan (Bonescan) or intraoperative monitoring of blood flow in the femoral head using a Codman Intra Cranial Pressure (ICP) probe
Findings / Results: The 10 year old girl, who was treated for severe acute on chronic SCFE had no AVN on postoperative SPECT scan. She was fully weight bearing 3 months after surgery without pain and ROM was almost restored at this stage. The final case underwent surgery 13 June 2016. We were able to perform intraoperative monitoring of blood flow in the femoral head using the ICP probe during the procedure. The femoral head was perfused throughout the procedure
Conclusions: These are early positive results of a new surgical procedure. Internationally there is a trend towards restoration of the hip anatomy for severe SCFE. We recommend that further use of this surgical procedure takes place in a national prospective study
Department of Childrens Orthopaedics, Aarhus University Hospital; Department of Childrens Orthopaedics, Aarhus University Hospital; Department of Childrens Orthopaedics, Aarhus University Hospital; Department of Childrens Orthopaedics, Aarhus University Hospital
Background: Slipped Capital Femoral Epiphysis (SCFE) is a condition that affects the hips in older children and adolescents. Current treatment is primarily based on in situ fixation using a single cannulated screw. The sub capital realignment osteotomy of the neck of femur for severe SCFE is gaining increasing acceptance. Anatomical realignment is performed after surgical dislocation of the affected hip joint. The procedure carries a risk for inducing avascular necrosis of the femoral head
Purpose / Aim of Study: To present early experience with a new setup for treating severe SCFE using new techniques for osteotomies of the proximal femur at Department of Childrens Orthopaedics, Aarhus University Hospital
Materials and Methods: Two osteotomies were performed in the following cases; severe acute on chronic SCFE in a 10 year girl and severe chronic SCFE in a 12 year girl. The sub capital realignment procedure was performed in both cases as described above. Perfusion of the femoral head was documented by either SPECT scan (Bonescan) or intraoperative monitoring of blood flow in the femoral head using a Codman Intra Cranial Pressure (ICP) probe
Findings / Results: The 10 year old girl, who was treated for severe acute on chronic SCFE had no AVN on postoperative SPECT scan. She was fully weight bearing 3 months after surgery without pain and ROM was almost restored at this stage. The final case underwent surgery 13 June 2016. We were able to perform intraoperative monitoring of blood flow in the femoral head using the ICP probe during the procedure. The femoral head was perfused throughout the procedure
Conclusions: These are early positive results of a new surgical procedure. Internationally there is a trend towards restoration of the hip anatomy for severe SCFE. We recommend that further use of this surgical procedure takes place in a national prospective study
Werner Hettwer, Andreas Krieg, Michael Mørk Petersen, Fritz Hefti
Ortopedisk Tumorsektion, Rigshospitalet; Childrens Hospital, University of Basel, Switzerland; Ortopedisk Tumorsektion, Rigshospitalet; Childrens Hospital, Univsersity of Basel, Switzerland
Background: Adequate resection and reconstruction of pelvic tumors can be very challenging. Complex anatomy and limited exposure can make safe and appropriate placement of resection lines difficult and subsequent endoprosthetic reconstruction demanding. Recent technological advances now permit virtual planning and production of complex patient- specific resection guides and patient- specific implant scaffolds prior to the intervention.
Purpose / Aim of Study: To report our experience with 5 cases of periacetabular tumors where resection and reconstruction were accomplished utilizing pre-operatively manufactured, specifically designed resection guides and corresponding composite implants consisting of a precisely matching and defect specific titanium scaffold as well as integrated plates to provide for immediate stable fixation and subsequent opportunity for ingrowth into the residual bone.
Materials and Methods: Accuracy for each osteotomy plane was determined by direct intraoperative measurement and independent assessment of histopathological margin status. VIrtual analysis of postoperative CT scans was performed in two cases.
Findings / Results: We report our experience with 5 cases of periacetabular tumors where resection and reconstruction were accomplished utilizing pre-operatively manufactured, specifically designed resection guides and corresponding composite implants consisting of a precisely matching and defect specific titanium scaffold as well as integrated plates to provide for immediate stable fixation and subsequent opportunity for ingrowth into the residual bone.
Conclusions: This technology appears to afford high intraoperative accuracy, surgeon confidence and decreased operative time and is certain to develop into a promising treatment option for complex pelvic tumors in the future.
Ortopedisk Tumorsektion, Rigshospitalet; Childrens Hospital, University of Basel, Switzerland; Ortopedisk Tumorsektion, Rigshospitalet; Childrens Hospital, Univsersity of Basel, Switzerland
Background: Adequate resection and reconstruction of pelvic tumors can be very challenging. Complex anatomy and limited exposure can make safe and appropriate placement of resection lines difficult and subsequent endoprosthetic reconstruction demanding. Recent technological advances now permit virtual planning and production of complex patient- specific resection guides and patient- specific implant scaffolds prior to the intervention.
Purpose / Aim of Study: To report our experience with 5 cases of periacetabular tumors where resection and reconstruction were accomplished utilizing pre-operatively manufactured, specifically designed resection guides and corresponding composite implants consisting of a precisely matching and defect specific titanium scaffold as well as integrated plates to provide for immediate stable fixation and subsequent opportunity for ingrowth into the residual bone.
Materials and Methods: Accuracy for each osteotomy plane was determined by direct intraoperative measurement and independent assessment of histopathological margin status. VIrtual analysis of postoperative CT scans was performed in two cases.
Findings / Results: We report our experience with 5 cases of periacetabular tumors where resection and reconstruction were accomplished utilizing pre-operatively manufactured, specifically designed resection guides and corresponding composite implants consisting of a precisely matching and defect specific titanium scaffold as well as integrated plates to provide for immediate stable fixation and subsequent opportunity for ingrowth into the residual bone.
Conclusions: This technology appears to afford high intraoperative accuracy, surgeon confidence and decreased operative time and is certain to develop into a promising treatment option for complex pelvic tumors in the future.
Nina Hardgrib, Mikala Wang, Anne Grethe Jurik, Klaus Kjær Petersen
of Pediatrics, Aarhus University Hospital, Skejby; of Clinical Microbiology, Aarhus University Hospital, Skejby; of Radiology, Aarhus University Hospital, NBG; of Orthopedic Surgery, Aarhus University Hospital, NBG
Background: The incidence and severity of PVL-positive MRSA infections are increasing and can cause patient hospitalization with high mortality and morbidity, and are difficult to treat.
Purpose / Aim of Study: To share our patient case to increase awareness and understanding of severe infections in interdisciplinary patients and improve the course of treatment
Materials and Methods: We describe the first case of PVL-positive MRSA septicemia with bilateral pneumonia, arthritis of the knee and osteomyelitis of the tibia in a child in Scandinavia.
Findings / Results: We describe our interdisciplinary treatment efforts with frequent surgical debridement, choices of antibiotics and radiological investigations and interpretations, which in our case resulted in a healthy patient without complications, a favorable outcome unlike those earlier described in the literature.
Conclusions: This case underlines the necessity of increased focus and close interdisciplinary cooperation on children with septic arthritis and osteomyelitis, especially in cases with initial treatment failure, and illustrates the paramount importance of surgical debridement.
of Pediatrics, Aarhus University Hospital, Skejby; of Clinical Microbiology, Aarhus University Hospital, Skejby; of Radiology, Aarhus University Hospital, NBG; of Orthopedic Surgery, Aarhus University Hospital, NBG
Background: The incidence and severity of PVL-positive MRSA infections are increasing and can cause patient hospitalization with high mortality and morbidity, and are difficult to treat.
Purpose / Aim of Study: To share our patient case to increase awareness and understanding of severe infections in interdisciplinary patients and improve the course of treatment
Materials and Methods: We describe the first case of PVL-positive MRSA septicemia with bilateral pneumonia, arthritis of the knee and osteomyelitis of the tibia in a child in Scandinavia.
Findings / Results: We describe our interdisciplinary treatment efforts with frequent surgical debridement, choices of antibiotics and radiological investigations and interpretations, which in our case resulted in a healthy patient without complications, a favorable outcome unlike those earlier described in the literature.
Conclusions: This case underlines the necessity of increased focus and close interdisciplinary cooperation on children with septic arthritis and osteomyelitis, especially in cases with initial treatment failure, and illustrates the paramount importance of surgical debridement.
Niels Egund
Dept. Radiology, Aarhus University Hospitals
Background: One of the most commonly required radiological measurements of the hip is the Wiberg center edge (WCE) angle. In the literature and by national orthopedic hip surgeons it has been claimed, that CE angles < 25° represent hip dysplasia.
Purpose / Aim of Study: To obtain evidence based national recommendations of measurement technique and normal values of the CE angle.
Materials and Methods: Literature review of studies regarding the normal values of the WCE angle; also, assessment of references used in the literature justifying recommendations of cut-off WCE angels of 25°.
Findings / Results: Two different landmarks on the acetabulum have been used for measurements. The most lateral edge of the acetabulum, is giving the lateral center edge (LCE) angle and the most lateral point of the acetabular sourcil, is giving the original WCE. The LCE angle has wrongly been referred to Wiberg. Based on a small material, Wiberg suggested a cut-off value of 20°. Using the LCE angle, several studies have confirmed normal cut-off values of 20°. Few have measured the WCE angle in a larger population of normal young subjects. The best documented material consists of 2,038 19-year-old Norwegians and the 2.5 percentile value for the WCE angle was 18° and 17° in males and females respectively. Using a cut-off angle of 25° for the WCE angle more than 25% of the Norwegian population was calculated to have dysplastic hips. In most publications using a cut-off angle of 25° in clinical studies of hip dysplasia, hip impingement and osteoarthritis there is a reference to Wiberg or references, which in second hand referred to Wiberg.
Conclusions: The WCE angle indicating hip dysplasia is below 17° - 19°. The commonly suggested cut-off value of 25° is not confirmed scientifically. Adequate measurements of the WCE angle require knowledge about normal imaging anatomy and pitfalls.
Dept. Radiology, Aarhus University Hospitals
Background: One of the most commonly required radiological measurements of the hip is the Wiberg center edge (WCE) angle. In the literature and by national orthopedic hip surgeons it has been claimed, that CE angles < 25° represent hip dysplasia.
Purpose / Aim of Study: To obtain evidence based national recommendations of measurement technique and normal values of the CE angle.
Materials and Methods: Literature review of studies regarding the normal values of the WCE angle; also, assessment of references used in the literature justifying recommendations of cut-off WCE angels of 25°.
Findings / Results: Two different landmarks on the acetabulum have been used for measurements. The most lateral edge of the acetabulum, is giving the lateral center edge (LCE) angle and the most lateral point of the acetabular sourcil, is giving the original WCE. The LCE angle has wrongly been referred to Wiberg. Based on a small material, Wiberg suggested a cut-off value of 20°. Using the LCE angle, several studies have confirmed normal cut-off values of 20°. Few have measured the WCE angle in a larger population of normal young subjects. The best documented material consists of 2,038 19-year-old Norwegians and the 2.5 percentile value for the WCE angle was 18° and 17° in males and females respectively. Using a cut-off angle of 25° for the WCE angle more than 25% of the Norwegian population was calculated to have dysplastic hips. In most publications using a cut-off angle of 25° in clinical studies of hip dysplasia, hip impingement and osteoarthritis there is a reference to Wiberg or references, which in second hand referred to Wiberg.
Conclusions: The WCE angle indicating hip dysplasia is below 17° - 19°. The commonly suggested cut-off value of 25° is not confirmed scientifically. Adequate measurements of the WCE angle require knowledge about normal imaging anatomy and pitfalls.