Different studies confirmed the increased radiological implantation accuracy for computer-assiste... more Different studies confirmed the increased radiological implantation accuracy for computer-assisted total knee replacements. There was no study stating a significant influence of the navigation technique for total knee arthroplasties on the early clinical outcomes. In these two case reports we try to show special indications for a navigated total knee replacement to utilize the benefits of a navigation system as efficiently as possible.Case 1 had a femoral neck fracture 3 years ago and was treated with a long femoral gamma nail. The hardware was still retained. Case 2 had a fracture of the femoral diaphysis 31 years ago and showed an extra-articular deformity in the frontal and sagittal planes. Both patients developed osteoarthritis of the ipsilateral knee and were implanted with a total knee prosthesis using a navigation system.In both cases the prosthesis components showed perfect radiological alignment. The clinical outcomes at the 3-month follow-up were very satisfying. In case 1...
Verschiedene Studien bestätigen die bessere radiologische Implantationsgenauigkeit durch die Navi... more Verschiedene Studien bestätigen die bessere radiologische Implantationsgenauigkeit durch die Navigation bei der Knietotalendoprothetik (KTEP). Es gibt aber keine Studie, die über einen signifikanten Einfluss der navigierten KTEP auf die kurzfristigen klinischen Ergebnisse berichtet. In diesen beiden Fallberichten versuchen wir besondere Indikationen für die navigierte KTEP aufzuzeigen, sodass die Vorteile eines Navigationssystems so effizient wie möglich genutzt werden können.Patientin 1 hatte sich vor 3 Jahren eine Fraktur des Schenkelhalses rechts zugezogen und war mit einem langen femoralen Gammanagel versorgt worden. Der Nagel wurde nach der Frakturheilung nicht entfernt. Patientin 2 hatte vor 31 Jahren eine Fraktur der Femurdiaphyse links erlitten und wies in frontaler und sagittaler Ebene eine extraartikuläre Deformität auf. Beide Patientinnen entwickelten eine Gonarthrose des ipsilateralen Kniegelenks. Sie wurden mit einem totalen Kniegelenkoberflächenersatz unter Verwendung ...
We present the current state-of-the art of computer-assisted interstitial (fractionated) brachyth... more We present the current state-of-the art of computer-assisted interstitial (fractionated) brachytherapy as a “picture-book” without wanting to give an in-depth presentation of either brachytherapy itself or of otolaryngologic aspects of oncologic treatment. However, our results show that 3D-computer-assisled navigation techniques can successfully be applied in interstitial brachytherapy to exactly plan the hollow-needle’s position(s) in order to reach a prospective planning
The articular surface replacement (ASR) total hip arthroplasty (THA) showed accelerated failure r... more The articular surface replacement (ASR) total hip arthroplasty (THA) showed accelerated failure rates due to adverse-reaction to metal debris (ARMD). Literature correlating preoperative with intraoperative revision findings respectively post-revision outcome results are rare. 30 of 99 available ASR THA were revised due to ARMD. Mean post-revision follow-up term was 2.3years. In part, preoperative data did not correlate with intraoperative revision findings. ARMD was even found in asymptomatic patients with non-elevated ion levels. Postoperative pain and metal ions decreased significantly (P≤0.016). Cobalt decreased faster than chrome. Patients with intraoperative pseudotumors, osteolysis or bilateral THA did not have higher pre- or postoperative ion values (P≥0.053). Females showed higher postoperative chrome levels (P=0.031). One major post-revision complication (femoral nerve palsy) and one re-revision (late onset infection) occurred.
The benefits of postoperative wound drainage in patients with total knee arthroplasty (TKA) with ... more The benefits of postoperative wound drainage in patients with total knee arthroplasty (TKA) with regards to mobilisation and wound healing were studied. We wanted to determine the efficacy of an autologous blood retransfusion system. 150 patients with TKA were divided into three groups of 50 patients: A) three wound drainages with an autotransfusion system and suction; B) no wound drainage; C) one intraarticular wound drainage without suction. Hemoglobin values, blood transfusion requirements, blood loss, postoperative range of motion, Insall knee score and rate of complications were observed and recorded. All patients were operated without tourniquets for lower blood loss. In the group of patients with wound drainage and a retransfusion system the requirement of postoperative additional blood transfusion was not significantly less than in the group without wound drainage. Group A had the highest blood loss of all. The group without wound drainage had more hematomas and wound healin...
Taper junctions of large diameter metal-on-metal femoral heads and femoral stems were described a... more Taper junctions of large diameter metal-on-metal femoral heads and femoral stems were described as metal ion generator due to accelerated wear and corrosion. However, literature about the Articular Surface Replacement (ASR) total hip arthroplasty (THA) invariably deals with stems manufactured by DePuy Orthopedics (Warsaw, IN, USA). Nothing is known whether different stems with common 12/14 mm tapers affect failure rate or ion release. 99 ASR THA (88 patients) implanted with CoxaFit or ARGE Geradschaft stems (K-Implant, Hannover, Germany) were retrospectively analyzed. After a mean follow-up of 3.5 years revision rate was 24.5%, mostly due to adverse reaction to metal debris (ARMD). CT scan revealed component loosening in 10.3% and pseudotumoral lesions in 12.6%. Elevated ion concentrations (>7 μg/l) were found in 38.6%.
Precise target localization is essential for brachytherapy. We have adapted the VBH (Vogele-Bale-... more Precise target localization is essential for brachytherapy. We have adapted the VBH (Vogele-Bale-Hohner) head holder (Wellhoefer Dosimetry, Schwarzenbruck, Germany), originally developed at the University of Innsbruck, for frameless stereotactic surgery, for use in brachytherapy of cranial tumors. The VBH head holder allows for rigid, noninvasive head fixation by means of an individualized upper dental cast. Registration rods, rigidly attached to the dental cast, provide stable external points of reference. The dental cast is sucked against the upper palate by vacuum, and then the fixated patient is scanned. During simulation, the targeting device can be positioned with respect to the virtual patient using the ISG Viewing Wand. Following simulation, the real patient is repositioned under vacuum control, the targeting device repositioned as well, and the actual brachytherapy initiated. The VBH head holder is well tolerated by patients and simple to use, and various studies have confirmed submillimeter accuracy. The modified head holder in combination with a new targeting device allows for precise and well-planned insertion of hollow needles into a tumor using frameless stereotactic systems as well as being compatible for uses in other fields.
Zusammenfassung Der intraoperative Einsatz von rahmenlosen stereotaktischen Navigationssystemen e... more Zusammenfassung Der intraoperative Einsatz von rahmenlosen stereotaktischen Navigationssystemen ermöglicht die exakte Visualisierung der Sonden- oder Instrumentenposition im Patienten in präoperativen CT/MR Datensätzen in Echtzeit. Die meisten verfügbaren Systeme erfordern eine zuverlässige Fixation des Patienten am Operationstisch. Die Fixierung mit Klebeband hat sich für die Kopf-Hals-Chirurgie als unzureichend herausgestellt, da die Elastizität des Bandes und die von ihm induzierte Weichteilverschiebung der
A new generation of implantation instruments were developed for quadriceps sparing surgical appro... more A new generation of implantation instruments were developed for quadriceps sparing surgical approaches during total knee arthroplasty (TKA). There is little information on the accuracy of the bone cuts performed with the side-cutting technique. A total of 100 patients were randomized to undergo computer-assisted TKA or non-navigated TKA using a mini-subvastus surgical approach and side-cutting implant instrumentation. The radiographic parameters, clinical outcomes and knee scores were evaluated 3 months postoperative. The mechanical axis of the limb was within 3 degrees varus/valgus in 76% of the patients who had navigated procedures versus 66% of patients who had conventional surgery. The tibial slope showed a rate of inaccuracy of 3 degrees or less for 78% of the patients in the navigated total knee arthroplasty group versus 66% of the patients in the conventional group. Clinical outcomes and knee scores were similar in both groups. The navigation technique could not compensate for shortcomings of the implantation instruments.
Several choices of instrument systems are available for minimally invasive surgical approaches. T... more Several choices of instrument systems are available for minimally invasive surgical approaches. There are reports that one alternative, the quadriceps sparing, side-cutting instrumentation, results in diminished implantation accuracy. A total of 108 patients were randomized to undergo TKA either using side-cutting implant instrumentation (Group A) or anterior-posterior mini-incision instrumentation (Group B). All TKAs were operated on with a minimal invasive, mini-midvastus surgical approach. 50% of the TKAs were performed with computer-assistance in each cohort. The radiographic parameters, clinical outcomes and knee scores were evaluated preoperatively and 3 months postoperative. In Group B, we found significantly higher accuracy for the mechanical axis of the limb (range +/-3 degrees: Group A 54% versus Group B 89%, p = <0.001), medial proximal tibial angle (range +/-3 degrees: Group A 85% versus Group B 98%, p = <0.027) and tibial slope (range +/-3 degrees: Group A 59% versus Group B 85%, p = <0.007). The application of the navigation system could only significantly reduce outliers (accuracy >3 degrees) in Group B. Clinical outcomes and knee scores were similar in both groups and were not influenced by computer-assistance. Using the anterior-posterior, mini-incision instruments for minimally invasive TKA will lead to higher implantation accuracy when compared to the quadriceps sparing side-cutting instrumentation. The navigation technique could not compensate for shortcomings of the side-cutting instrumentation. The clinical relevance of this study is that the quadriceps sparing side-cutting instrumentation should not be used for TKA because of unacceptable reduced implantation accuracy.
In the literature, studies of computer-assisted total knee arthroplasty (TKA) after mid-term peri... more In the literature, studies of computer-assisted total knee arthroplasty (TKA) after mid-term period are not conclusive and long-term data are rare. In a prospective, randomized, comparative study 100 conventional TKAs (group REG) were compared with 100 computer-assisted TKAs (group NAV). Minimum follow-up was 5years. No difference in implant failure was found with 1.1% in group NAV versus 4.6% in group REG (P=0.368). Group NAV showed a significantly less mean deviation of mechanical limb axis (P=0.015), more TKAs (90% versus 81% in group REG) were within 3° varus/valgus and a higher tibial slope and lateral distal femoral angle (LDFA) accuracy was found (P≤0.034). Clinical investigational parameters showed no differences (P≥0.058). Insall and HSS score total were also higher in group NAV (P≤0.016).
Different studies confirmed the increased radiological implantation accuracy for computer-assiste... more Different studies confirmed the increased radiological implantation accuracy for computer-assisted total knee replacements. There was no study stating a significant influence of the navigation technique for total knee arthroplasties on the early clinical outcomes. In these two case reports we try to show special indications for a navigated total knee replacement to utilize the benefits of a navigation system as efficiently as possible.Case 1 had a femoral neck fracture 3 years ago and was treated with a long femoral gamma nail. The hardware was still retained. Case 2 had a fracture of the femoral diaphysis 31 years ago and showed an extra-articular deformity in the frontal and sagittal planes. Both patients developed osteoarthritis of the ipsilateral knee and were implanted with a total knee prosthesis using a navigation system.In both cases the prosthesis components showed perfect radiological alignment. The clinical outcomes at the 3-month follow-up were very satisfying. In case 1 the femoral nail did not have to be removed, thus decreasing surgery duration by 40-60 min.In both cases, the impossibility of using a femoral intramedullary alignment rod could be compensated for by the navigation system.
Different studies confirmed the increased radiological implantation accuracy for computer-assiste... more Different studies confirmed the increased radiological implantation accuracy for computer-assisted total knee replacements. There was no study stating a significant influence of the navigation technique for total knee arthroplasties on the early clinical outcomes. In these two case reports we try to show special indications for a navigated total knee replacement to utilize the benefits of a navigation system as efficiently as possible.Case 1 had a femoral neck fracture 3 years ago and was treated with a long femoral gamma nail. The hardware was still retained. Case 2 had a fracture of the femoral diaphysis 31 years ago and showed an extra-articular deformity in the frontal and sagittal planes. Both patients developed osteoarthritis of the ipsilateral knee and were implanted with a total knee prosthesis using a navigation system.In both cases the prosthesis components showed perfect radiological alignment. The clinical outcomes at the 3-month follow-up were very satisfying. In case 1...
Verschiedene Studien bestätigen die bessere radiologische Implantationsgenauigkeit durch die Navi... more Verschiedene Studien bestätigen die bessere radiologische Implantationsgenauigkeit durch die Navigation bei der Knietotalendoprothetik (KTEP). Es gibt aber keine Studie, die über einen signifikanten Einfluss der navigierten KTEP auf die kurzfristigen klinischen Ergebnisse berichtet. In diesen beiden Fallberichten versuchen wir besondere Indikationen für die navigierte KTEP aufzuzeigen, sodass die Vorteile eines Navigationssystems so effizient wie möglich genutzt werden können.Patientin 1 hatte sich vor 3 Jahren eine Fraktur des Schenkelhalses rechts zugezogen und war mit einem langen femoralen Gammanagel versorgt worden. Der Nagel wurde nach der Frakturheilung nicht entfernt. Patientin 2 hatte vor 31 Jahren eine Fraktur der Femurdiaphyse links erlitten und wies in frontaler und sagittaler Ebene eine extraartikuläre Deformität auf. Beide Patientinnen entwickelten eine Gonarthrose des ipsilateralen Kniegelenks. Sie wurden mit einem totalen Kniegelenkoberflächenersatz unter Verwendung ...
We present the current state-of-the art of computer-assisted interstitial (fractionated) brachyth... more We present the current state-of-the art of computer-assisted interstitial (fractionated) brachytherapy as a “picture-book” without wanting to give an in-depth presentation of either brachytherapy itself or of otolaryngologic aspects of oncologic treatment. However, our results show that 3D-computer-assisled navigation techniques can successfully be applied in interstitial brachytherapy to exactly plan the hollow-needle’s position(s) in order to reach a prospective planning
The articular surface replacement (ASR) total hip arthroplasty (THA) showed accelerated failure r... more The articular surface replacement (ASR) total hip arthroplasty (THA) showed accelerated failure rates due to adverse-reaction to metal debris (ARMD). Literature correlating preoperative with intraoperative revision findings respectively post-revision outcome results are rare. 30 of 99 available ASR THA were revised due to ARMD. Mean post-revision follow-up term was 2.3years. In part, preoperative data did not correlate with intraoperative revision findings. ARMD was even found in asymptomatic patients with non-elevated ion levels. Postoperative pain and metal ions decreased significantly (P≤0.016). Cobalt decreased faster than chrome. Patients with intraoperative pseudotumors, osteolysis or bilateral THA did not have higher pre- or postoperative ion values (P≥0.053). Females showed higher postoperative chrome levels (P=0.031). One major post-revision complication (femoral nerve palsy) and one re-revision (late onset infection) occurred.
The benefits of postoperative wound drainage in patients with total knee arthroplasty (TKA) with ... more The benefits of postoperative wound drainage in patients with total knee arthroplasty (TKA) with regards to mobilisation and wound healing were studied. We wanted to determine the efficacy of an autologous blood retransfusion system. 150 patients with TKA were divided into three groups of 50 patients: A) three wound drainages with an autotransfusion system and suction; B) no wound drainage; C) one intraarticular wound drainage without suction. Hemoglobin values, blood transfusion requirements, blood loss, postoperative range of motion, Insall knee score and rate of complications were observed and recorded. All patients were operated without tourniquets for lower blood loss. In the group of patients with wound drainage and a retransfusion system the requirement of postoperative additional blood transfusion was not significantly less than in the group without wound drainage. Group A had the highest blood loss of all. The group without wound drainage had more hematomas and wound healin...
Taper junctions of large diameter metal-on-metal femoral heads and femoral stems were described a... more Taper junctions of large diameter metal-on-metal femoral heads and femoral stems were described as metal ion generator due to accelerated wear and corrosion. However, literature about the Articular Surface Replacement (ASR) total hip arthroplasty (THA) invariably deals with stems manufactured by DePuy Orthopedics (Warsaw, IN, USA). Nothing is known whether different stems with common 12/14 mm tapers affect failure rate or ion release. 99 ASR THA (88 patients) implanted with CoxaFit or ARGE Geradschaft stems (K-Implant, Hannover, Germany) were retrospectively analyzed. After a mean follow-up of 3.5 years revision rate was 24.5%, mostly due to adverse reaction to metal debris (ARMD). CT scan revealed component loosening in 10.3% and pseudotumoral lesions in 12.6%. Elevated ion concentrations (>7 μg/l) were found in 38.6%.
Precise target localization is essential for brachytherapy. We have adapted the VBH (Vogele-Bale-... more Precise target localization is essential for brachytherapy. We have adapted the VBH (Vogele-Bale-Hohner) head holder (Wellhoefer Dosimetry, Schwarzenbruck, Germany), originally developed at the University of Innsbruck, for frameless stereotactic surgery, for use in brachytherapy of cranial tumors. The VBH head holder allows for rigid, noninvasive head fixation by means of an individualized upper dental cast. Registration rods, rigidly attached to the dental cast, provide stable external points of reference. The dental cast is sucked against the upper palate by vacuum, and then the fixated patient is scanned. During simulation, the targeting device can be positioned with respect to the virtual patient using the ISG Viewing Wand. Following simulation, the real patient is repositioned under vacuum control, the targeting device repositioned as well, and the actual brachytherapy initiated. The VBH head holder is well tolerated by patients and simple to use, and various studies have confirmed submillimeter accuracy. The modified head holder in combination with a new targeting device allows for precise and well-planned insertion of hollow needles into a tumor using frameless stereotactic systems as well as being compatible for uses in other fields.
Zusammenfassung Der intraoperative Einsatz von rahmenlosen stereotaktischen Navigationssystemen e... more Zusammenfassung Der intraoperative Einsatz von rahmenlosen stereotaktischen Navigationssystemen ermöglicht die exakte Visualisierung der Sonden- oder Instrumentenposition im Patienten in präoperativen CT/MR Datensätzen in Echtzeit. Die meisten verfügbaren Systeme erfordern eine zuverlässige Fixation des Patienten am Operationstisch. Die Fixierung mit Klebeband hat sich für die Kopf-Hals-Chirurgie als unzureichend herausgestellt, da die Elastizität des Bandes und die von ihm induzierte Weichteilverschiebung der
A new generation of implantation instruments were developed for quadriceps sparing surgical appro... more A new generation of implantation instruments were developed for quadriceps sparing surgical approaches during total knee arthroplasty (TKA). There is little information on the accuracy of the bone cuts performed with the side-cutting technique. A total of 100 patients were randomized to undergo computer-assisted TKA or non-navigated TKA using a mini-subvastus surgical approach and side-cutting implant instrumentation. The radiographic parameters, clinical outcomes and knee scores were evaluated 3 months postoperative. The mechanical axis of the limb was within 3 degrees varus/valgus in 76% of the patients who had navigated procedures versus 66% of patients who had conventional surgery. The tibial slope showed a rate of inaccuracy of 3 degrees or less for 78% of the patients in the navigated total knee arthroplasty group versus 66% of the patients in the conventional group. Clinical outcomes and knee scores were similar in both groups. The navigation technique could not compensate for shortcomings of the implantation instruments.
Several choices of instrument systems are available for minimally invasive surgical approaches. T... more Several choices of instrument systems are available for minimally invasive surgical approaches. There are reports that one alternative, the quadriceps sparing, side-cutting instrumentation, results in diminished implantation accuracy. A total of 108 patients were randomized to undergo TKA either using side-cutting implant instrumentation (Group A) or anterior-posterior mini-incision instrumentation (Group B). All TKAs were operated on with a minimal invasive, mini-midvastus surgical approach. 50% of the TKAs were performed with computer-assistance in each cohort. The radiographic parameters, clinical outcomes and knee scores were evaluated preoperatively and 3 months postoperative. In Group B, we found significantly higher accuracy for the mechanical axis of the limb (range +/-3 degrees: Group A 54% versus Group B 89%, p = <0.001), medial proximal tibial angle (range +/-3 degrees: Group A 85% versus Group B 98%, p = <0.027) and tibial slope (range +/-3 degrees: Group A 59% versus Group B 85%, p = <0.007). The application of the navigation system could only significantly reduce outliers (accuracy >3 degrees) in Group B. Clinical outcomes and knee scores were similar in both groups and were not influenced by computer-assistance. Using the anterior-posterior, mini-incision instruments for minimally invasive TKA will lead to higher implantation accuracy when compared to the quadriceps sparing side-cutting instrumentation. The navigation technique could not compensate for shortcomings of the side-cutting instrumentation. The clinical relevance of this study is that the quadriceps sparing side-cutting instrumentation should not be used for TKA because of unacceptable reduced implantation accuracy.
In the literature, studies of computer-assisted total knee arthroplasty (TKA) after mid-term peri... more In the literature, studies of computer-assisted total knee arthroplasty (TKA) after mid-term period are not conclusive and long-term data are rare. In a prospective, randomized, comparative study 100 conventional TKAs (group REG) were compared with 100 computer-assisted TKAs (group NAV). Minimum follow-up was 5years. No difference in implant failure was found with 1.1% in group NAV versus 4.6% in group REG (P=0.368). Group NAV showed a significantly less mean deviation of mechanical limb axis (P=0.015), more TKAs (90% versus 81% in group REG) were within 3° varus/valgus and a higher tibial slope and lateral distal femoral angle (LDFA) accuracy was found (P≤0.034). Clinical investigational parameters showed no differences (P≥0.058). Insall and HSS score total were also higher in group NAV (P≤0.016).
Different studies confirmed the increased radiological implantation accuracy for computer-assiste... more Different studies confirmed the increased radiological implantation accuracy for computer-assisted total knee replacements. There was no study stating a significant influence of the navigation technique for total knee arthroplasties on the early clinical outcomes. In these two case reports we try to show special indications for a navigated total knee replacement to utilize the benefits of a navigation system as efficiently as possible.Case 1 had a femoral neck fracture 3 years ago and was treated with a long femoral gamma nail. The hardware was still retained. Case 2 had a fracture of the femoral diaphysis 31 years ago and showed an extra-articular deformity in the frontal and sagittal planes. Both patients developed osteoarthritis of the ipsilateral knee and were implanted with a total knee prosthesis using a navigation system.In both cases the prosthesis components showed perfect radiological alignment. The clinical outcomes at the 3-month follow-up were very satisfying. In case 1 the femoral nail did not have to be removed, thus decreasing surgery duration by 40-60 min.In both cases, the impossibility of using a femoral intramedullary alignment rod could be compensated for by the navigation system.
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