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Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_7 | Pages 30 - 30
4 Apr 2023
Neunaber C Long Y Noack S Krettek C Bundkirchen K
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Due to their immunomodulatory and regenerative capacity, human bone marrow-derived mesenchymal stromal cells (hBMSCs) are promising in the treatment of polytrauma patients. However, few studies evaluated the effects of sera from polytraumatized patients on hBMSCs. The aim of this study was to explore changes in hBMSCs exposed to serum from polytrauma patients from different time points after trauma.

Sera from 84 patients on day 1 (D1), 5 (D5) and 10 (D10) after polytrauma (ISS ≥ 16) were pooled respectively to test the differential influence on hBMSC. As a control, sera from three healthy age- and gender-matched donors (HS) were collected. The pooled sera were analyzed by Multicytokine Array for pro-/anti-inflammatory cytokines. For the cell culture experiments, hBMSCs from four healthy donors were used. The influence of the different sera on hBMSC regarding cell proliferation, colony forming unit-fibroblast (CFU-F) assay, cell viability and toxicity, cell migration, as well as osteogenic and chondrogenic differentiation was analyzed. One-Way-ANOVA and LSD-test were used for the parametric, Kruskal-Wallis-test for non-parametric data. p≤0.05 was considered as statistically significant.

The results showed that D5 serum reduced hBMSCs cell proliferation capacity by 41.26% (p=0.000) compared with HS and increased the proportion of dead cells by 3.19% (p=0.008) and 2.25% (p=0.020) compared with D1 and D10. The frequency of CFU-F was reduced by 49.08% (p=0.041) in D5 and 53.99% (p=0.027) in D10 compared with HS, whereas the other parameters were not influenced.

The serological effect of polytrauma on hBMSCs was related to the time after trauma. It is disadvantageous to use BMSCs in polytraumatized patients five days after the incidence as obvious cytological changes could be found at that time point. However, it is promising to use hBMSCs to treat polytrauma after 10 days, combined with the concept of “Damage Control Orthopaedics” (DCO).


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_13 | Pages 48 - 48
1 Nov 2021
Bundkirchen K Ye W Xu B Krettek C Relja B Neunaber C
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Introduction and Objective

In multiple trauma patients, as well as in the healing of isolated fractures (Fx) with heavy bleeding (trauma haemorrhage, TH), complications occur very often. This is particularly evident in elderly patients over 65 years of age. Since these accompanying circumstances strongly influence the clinical course of treatment, the influence of age on bone regeneration after femoral fracture and severe blood loss was investigated in this study.

Materials and Methods

12 young (17–26 weeks) and 12 old (64–72 weeks) male C57BL / 6J mice per group were examined. The fracture group Fx underwent an osteotomy after applying an external fixator. The THFx group also received blood pressure-controlled trauma hemorrhage (35 mmHg for 90 minutes) and reperfusion with Ringer's solution for 30 minutes. The Sham group received only the catheter and one external fixator. μCT scans of the femora were performed in vivo after 2 weeks and ex vivo after 3 weeks. Histological and biomechanical examinations were also carried out. The statistical significance was set at p ≤ 0.05. The non-normally distributed data were analyzed using the Mann-Whitney-U or Kruskal-Wallis test.


The Bone & Joint Journal
Vol. 100-B, Issue 9 | Pages 1214 - 1219
1 Sep 2018
Winkelmann M Lopez Izquierdo M Clausen J Liodakis E Mommsen P Blossey R Krettek C Zeckey C

Aims

This study aimed to analyze the correlation between transverse process (TP) fractures of the fourth (L4) and fifth (L5) lumbar vertebrae and biomechanical and haemodynamic stability in patients with a pelvic ring injury, since previous data are inconsistent.

Patients and Methods

The study is a retrospective matched-pair analysis of patients with a pelvic fracture according to the modified Tile AO Müller and the Young and Burgess classification who presented to a level 1 trauma centre between January 2005 and December 2014.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_4 | Pages 91 - 91
1 Apr 2018
Bundkirchen K Macke C Reifenrath J Angrisani N Schäck LM Noack S Welke B Krettek C Neunaber C
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Purpose

In patients with multiple trauma delayed fracture healing is often diagnosed, but the pathomechanisms are not well known yet. The purpose of the study is to evaluate the effect of a severe hemorrhagic shock on fracture healing in a murine model.

Methods

10 male C57BL/6N mice per group (Fx, TH, THFx, Sham) and point in time were used. The Fx-group received an osteotomy after implantation of a fixateur extern. The TH-group got a pressure controlled hemorrhagic shock with a mean arterial blood pressure of 35 mmHg over 90 minutes. Resuscitation with 4 times the shed blood volume of Ringer solution was performed. The THFx group got both. Sham-animals received the implantation of a catheter and a fixateur extern but no blood loss or osteotomy. After 1, 2, 3, 4 or 6 weeks the animals were sacrificed. For the biomechanics the bones were analyzed via X-ray, µCT and underwent a 3-point bending test. The nondecalcified histology based on slices of Technovit 9100. The signaling pathway was analyzed via RT2 Profiler™ PCR Array Mouse Osteoporosis, Western Blot and Quantikine ELISA for RankL and OPG. Statistical significance was set at p < 0.05. Comparisons between groups were performed using the Mann–Whitney U (Fx vs. THFx) or Kruskal-Wallis Test (other groups).


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_3 | Pages 67 - 67
1 Apr 2018
Schäck L Noack S Krettek C Neunaber C
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Introduction

Human bone marrow-derived mesenchymal stem cells (hBMSCs) can adopt either an immune suppressive or stimulative phenotype in response to cytokines and pathogen-associated molecular patterns (PAMPs). It is known that the glycoprotein CD24 allows for the discrimination between PAMPs and DAMPs in dendritic cells. We were able to show previously that CD24 is expressed by hBMSCs and found that its overexpression leads to the downregulation of NF-kB-regulated genes, as well as induction of the anti-inflammatory TGF beta.

In the present study the influence of various PAMPs and cytokines on the expression of CD24 in hBMSCs was analysed. Furthermore, it was tested whether in vivo-CD24-positive (CD24+) and in vivo-CD24-negative (CD24-) hBMSCs differ in regard to classical hBMSC or immune-associated surface antigens.

Methods

hBMSCs were enriched by density gradient centrifugation, cultured in vitro until passage 3 and subsequently stimulated with PAMPs or cytokines (IFN gamma, TGF beta) before analysing the expression of CD24 via qRT-PCR. Cells expressing CD24 in vivo (CD24+ hBMSCs) were enriched from bone marrow aspirates after density gradient centrifugation by the use of magnetic-associated cell sorting (MACS). Successful enrichment was evaluated by flow cytometric analysis. The enriched cells were subsequently cultured in comparison to the CD24-depleted cell population (CD24- hBMSCs) under identical conditions. The expression of various cell surface markers was compared between these two populations using flow cytometry.


Bone & Joint Research
Vol. 7, Issue 3 | Pages 213 - 222
1 Mar 2018
Tang X Teng S Petri M Krettek C Liu C Jagodzinski M

Objectives

The aims of this study were to determine whether the administration of anti-inflammatory and antifibrotic agents affect the proliferation, viability, and expression of markers involved in the fibrotic development of the fibroblasts obtained from arthrofibrotic tissue in vitro, and to evaluate the effect of the agents on arthrofibrosis prevention in vivo.

Methods

Dexamethasone, diclofenac, and decorin, in different concentrations, were employed to treat fibroblasts from arthrofibrotic tissue (AFib). Cell proliferation was measured by DNA quantitation, and viability was analyzed by Live/Dead staining. The levels of procollagen type I N-terminal propeptide (PINP) and procollagen type III N-terminal propeptide (PIIINP) were evaluated with enzyme-linked immunosorbent assay (ELISA) kits. In addition, the expressions of fibrotic markers were detected by real-time polymerase chain reaction (PCR). Fibroblasts isolated from healthy tissue (Fib) served as control. Further, a rabbit model of joint contracture was used to evaluate the antifibrotic effect of the three different agents.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_20 | Pages 42 - 42
1 Dec 2017
Steimer D Suero E Luecke U Stuebig T Krettek C Liodakis E
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INTRODUCTION

To test whether there are differences in postoperative mechanical and component alignment, and in functional results, between conventional, navigated and patient-specific total knee arthroplasties in a low-volume centre?

MATERIAL AND METHODS

Retrospective cohort study of 391 patients who received conventional, navigated or patient- specific primary cemented TKA in a low-volume hospital.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_20 | Pages 65 - 65
1 Dec 2017
Macke C Westphal R Citak M Hawi N Liodakis E Krettek C Stuebig T Suero EM
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Introduction

High tibial osteotomy (HTO) is a commonly used surgical technique for treating moderate osteoarthritis (OA) of the medial compartment of the knee by shifting the center of force towards the lateral compartment. The amount of alignment correction to be performed is usually calculated prior to surgery and it's based on the patient's lower limb alignment using long-leg radiographs. While the procedure is generally effective at relieving symptoms, an accurate estimation of change in intraarticular contact pressures and contact surface area has not been developed. Using electromyography (EMG), Meyer et al. attempted to predict intraarticular contact pressures during gait patterns in a patient who had received a cruciate retaining force-measuring tibial prosthesis. Lundberg et al. used data from the Third Grand Challenge Competition to improve contact force predictions in total knee replacement. Mina et al. performed high tibial osteotomy on eight human cadaveric knees with osteochondral defects in the medial compartment. They determined that complete unloading of the medial compartment occurred at between 6° and 10° of valgus, and that contact pressure was similarly distributed between the medial and lateral compartments at alignments of 0° to 4° of valgus. In the current study, we hypothesised that it would be possible to predict the change in intra-articular pressures based on extra-articular data acquisition.

Methods

Seven cadavers underwent an HTO procedure with sequential 5º valgus realignment of the leg up to 15º of correction. A previously developed stainless-steel device with integrated load cell was used to axially load the leg. Pressure-sensitive sensors were used to measure intra-articular contact pressures. Intraoperative changes in alignment were monitored in real time using computer navigation. An axial loading force was applied to the leg in the caudal-craneal direction and gradually ramped up from 0 to 550 N. Intra-articular contact pressure (kg) and contact area (mm2) data were collected. Generalised linear models were constructed to estimate the change in contact pressure based on extra-articular force and alignment data.


The Bone & Joint Journal
Vol. 99-B, Issue 2 | Pages 255 - 260
1 Feb 2017
Macke C Winkelmann M Mommsen P Probst C Zelle B Krettek C Zeckey C

Aims

To analyse the influence of upper extremity trauma on the long-term outcome of polytraumatised patients.

Patients and Methods

A total of 629 multiply injured patients were included in a follow-up study at least ten years after injury (mean age 26.5 years, standard deviation 12.4). The extent of the patients’ injury was classified using the Injury Severity Score. Outcome was measured using the Hannover Score for Polytrauma Outcome (HASPOC), Short Form (SF)-12, rehabilitation duration, and employment status. Outcomes for patients with and without a fracture of the upper extremity were compared and analysed with regard to specific fracture regions and any additional brachial plexus lesion.


The Bone & Joint Journal
Vol. 97-B, Issue 5 | Pages 696 - 704
1 May 2015
Kenawey M Krettek C Addosooki A Salama W Liodakis E

Unstable pelvic injuries in young children with an immature pelvis have different modes of failure from those in adolescents and adults. We describe the pathoanatomy of unstable pelvic injuries in these children, and the incidence of associated avulsion of the iliac apophysis and fracture of the ipsilateral fifth lumbar transverse process (L5-TP). We retrospectively reviewed the medical records of 33 children with Tile types B and C pelvic injuries admitted between 2007 and 2014; their mean age was 12.6 years (2 to 18) and 12 had an immature pelvis. Those with an immature pelvis commonly sustained symphyseal injuries anteriorly with diastasis, rather than the fractures of the pubic rami seen in adolescents. Posteriorly, transsacral fractures were more commonly encountered in mature children, whereas sacroiliac dislocations and fracture-dislocations were seen in both age groups. Avulsion of the iliac apophysis was identified in eight children, all of whom had an immature pelvis with an intact ipsilateral L5-TP. Young children with an immature pelvis are more susceptible to pubic symphysis and sacroiliac diastasis, whereas bony failures are more common in adolescents. Unstable pelvic injuries in young children are commonly associated with avulsion of the iliac apophysis, particularly with displaced SI joint dislocation and an intact ipsilateral L5-TP.

Cite this article: Bone Joint J 2015; 97-B:696–704.


The Bone & Joint Journal
Vol. 97-B, Issue 2 | Pages 173 - 176
1 Feb 2015
Omar M Ettinger M Reichling M Petri M Guenther D Gehrke T Krettek C Mommsen P

The aim of this study was to assess the role of synovial C-reactive protein (CRP) in the diagnosis of chronic periprosthetic hip infection. We prospectively collected synovial fluid from 89 patients undergoing revision hip arthroplasty and measured synovial CRP, serum CRP, erythrocyte sedimentation rate (ESR), synovial white blood cell (WBC) count and synovial percentages of polymorphonuclear neutrophils (PMN). Patients were classified as septic or aseptic by means of clinical, microbiological, serum and synovial fluid findings. The high viscosity of the synovial fluid precluded the analyses in nine patients permitting the results in 80 patients to be studied. There was a significant difference in synovial CRP levels between the septic (n = 21) and the aseptic (n = 59) cohort. According to the receiver operating characteristic curve, a synovial CRP threshold of 2.5 mg/l had a sensitivity of 95.5% and specificity of 93.3%. The area under the curve was 0.96. Compared with serum CRP and ESR, synovial CRP showed a high diagnostic value. According to these preliminary results, synovial CRP may be a useful parameter in diagnosing chronic periprosthetic hip infection.

Cite this article: Bone Joint J 2015; 97-B:173–6.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_IV | Pages 67 - 67
1 Mar 2012
Pape H Rixen D Morley J Ellingson C Dumont C Garving C Vaske B Mueller M Krettek C Giannoudis P
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Purpose

The timing of definitive fixation for major fractures in polytrauma patients is controversial. To clarify this aspect of trauma management, we randomised patients with blunt multiple injuries to either initial definitive stabilisation of the femur shaft with an intramedullary nail or an external fixator which was converted to an intramedullary nail at a secondary procedure and documented the post-operative clinical condition.

Methods

Multiply injured patients with femoral shaft fractures were randomised to either initial (<24 hours) intramedullary femoral nailing or to initial external fixation and conversion to an intramedullary nail at a later phase. Inclusion criteria: New Injury Severity Score >16 points, or 3 fractures and Abbreviated Injury Scale score >2 points and another injury (Abbreviated Injury Scale score >2 points), and age 18 to 65 years. Exclusion criteria: unstable or patients in extremis. Patients were graded as stable or borderline (increased risk of systemic complications). OUTCOMES: Incidence of acute lung injuries.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_II | Pages 92 - 92
1 Feb 2012
Giannoudis P Allami M Harwood P Macdonald D Dimitriou R Pape H Krettek C
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We aimed to investigate the treatment and outcome of patients over 65 years of age with tibial Pilon fracture. Patients were treated by primary open reduction and internal fixation or external fixation (EF) as determined by local soft tissue conditions. Patient course, incidence of radiological osteoarthritis and functional outcome using the SF-36 questionnaire were recorded. All patients were evaluated serially until discharge from final follow-up. The mean follow-up time was 28 months (12-45). Statistical analysis was performed using Analyse-it(tm) software for Excel.

In total 25 patients were studied. Two patients died before completion of treatment and were excluded from the final analysis. Therefore, 23 patients (10 male) were included with a mean age of 70.9 years (range 66-89) and a mean ISS of 10.25 (range 9-22). There were 4 grade IIIb open injuries.

Three patients suffered superficial tibial wound infection. Two patients underwent early secondary amputation due to deep bone sepsis within 8 weeks of injury. One patient in the ORIF group underwent primary arthrodesis, which was subsequently revised due to non-union. 3 patients underwent secondary bone grafting to enhance healing, performed at 2, 6 and 9 weeks. 2 patients with metal work failure underwent subsequent revision of ORIF and progressed to union; the mean time to union was 33.8 weeks. At final follow-up 7 (28%) patients had radiological features of osteoarthritis but none had symptoms severe enough to warrant ankle arthrodesis. There were significant differences from the USA norm in physical function score, role physical score, and physical component score, (p< 0.01).

Conclusion/Significance

In older patients local complications are relatively common and clinical vigilance must be maintained in order to allow appropriate intervention during their post-operative course. Despite the incidence of radiological post-traumatic arthrosis, none of the patients progressed to ankle fusion.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_II | Pages 139 - 139
1 May 2011
Gaulke R Oszwald M Probst C Mommsen P Klein M Hildebrand F Krettek C
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Introduction: Various variants of the extensor indicis (EI) have be described in the literature. We wanted to detect whether there exist any variants of the EI that may cause restricted mobility of the thumb following EI transposition to the extensor pollicis longus (EPL).

Patients & method: Intraoperatively the function of the extensor tendons of 168 hands (98 right / 70 left) of 159 patients (96 female / 63 male) were examined. The function of the muscles was simulated using a tendon-hook. For ethical reasons the approach was not extended for the study.

Results: In 34 of 168 hands 39 accessory tendons were found: 8 were localized between EPL and EI (1 from the EPL to the index; 3 extensor pollicis et indicis; 1 from the EI-muscle to the thumb; 3 to the radial extensor hood of the index). 31 accessory tendon were found ulnar to the EI (2 to the ulnar extensor hood of the index; 25 to the middle finger; 3 to the ring finger; 1 to the little finger). The EI was missing in only one hand, were a strong extensor anularis-tendon was found, which would have been suitable for EPL-reconstruction. 8 of these variants would hinder the thumb from isolated extension following EPL-reconstruction with the EI-tendon.

Conclusion: The extensor tendons should be inspected carefully through EI-transposition for reconstruction of EPL to ensure a free function of the thumb postoperatively. Small accessory tendons that may cause trouble should be cut, strong tendons should be transposed together with the EI-tendon.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_II | Pages 346 - 346
1 May 2010
Tzioupis C Riexen D Dumont C Pardini D Mueller M Gruner A Krettek C Pape H Giannoudis P
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Patients with bilateral femur shaft fractures are known to have a higher rate of complications when compared with those who have unilateral fractures. Many contributing factors have been considered responsible, however due to the heterogeneity of the studied populations solid conclusions cannot be substantiated. Patients included in our study were separated according to the presence of a unilateral (group USF) (n=146) versus bilateral femur shaft fracture (group BSF) (n=19)Endpoints of the study included the incidence of systemic (SIRS, Sepsis, Acute Lung Injuries) complications. The perioperative assessment included documentation of clinical and laboratory data assessing blood loss, coagulopathy, wound infection, and pneumonia. Local (wound infection, compartment syndrome etc.) and systemic complications (ALI, MOF, Sepsis) were documented. Statistical analyses were conducted to examine the relation between the occurrence of unilateral versus bilateral femoral fractures and variables indexing patient demographic characteristics and other indicators of initial injury severity. Independent sample t-tests were used to examine treatment group differences for variables that approximated a Gaussian distribution. For non-normal indicators of injury severity Mann-Whitney tests were performed. Pearson chi-square tests were performed for binary indicators of injury severity, except when expected cell counts did not exceed 5 participants. When this occurred, the Fisher exact test was used Evidence indicated that patients who suffered a bilateral femoral fracture were significantly more likely to have hemothorax and receive a blood transfusion upon admission to the hospital in comparison to patients who suffered a unilateral femoral fracture. Bivariate analyses also indicated that patients with bilateral femoral fractures exhibited a longer clinical recovery time and were more likely to experience clinical complications in comparison to those with unilateral fractures. However, there were no significant differences between the fracture groups in terms of the number of hours spent on a ventilator or the occurrence of pneumonia, acute lung injury, acute respiratory distress, sepsis, and multiple organ failure following surgery. Patients in borderline condition spent significantly more time in the ICU in comparison to those in stable condition. The high incidence of posttraumatic complications in poly-trauma patients with bilateral femur shaft fractures is caused by the accompanying injuries rather than by the additional femur fracture itself. It also documents that a thorough preoperative assessment can help differentiate those who have a high like hood of developing systemic complications from those who do not.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_I | Pages 94 - 94
1 Mar 2009
Citak M Gaulke R Kendoff D Hamwi I Krettek C Hüfner T
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Introduction: Image based navigation is able to increase precision and reduce intraoperative radiation time in drilling procedures in orthopeadic trauma indications. Due to specific anatomic conditions and necessary adequate fluoroscopic visualizing, specific indications need intraoperative 3-D fluoroscopy based navigation modalities. This kind of navigation has already been successfully used in several orthopaedic interventions. The complex anatomic structure of the scaphoid, the suggested minimal invasiveness and misplacement rates of the screws make 2-D based fluoroscopic navigation impossible. Missing options for a stable reference marker fixation at the scaphoid or carpus did not allow an intraoperative registration for the navigation. We report about the development of an adequate non invasive fixation technique of the reference marker for navigated interventions and the first implementation of 3-D fluoroscopy based scaphoid screws.

Materials and method: Fixation of the reference marker was achieved by immobilisation of the complete hand and forearm in maximum dorsal extension of the wrist. We used a completely new developed radiolucent hand fixation device (HFD) fixed nonivasively to the carpus and a conventional navigation system (Brainlab, Germany) in combination with 3-D fluoroscopic imaging (Iso-C, Siemens, Germany).

Tests were done on 10 intact specimen and the process included the initial drilling and final placement of an osteosynthetic screw. Postoperative placement was controlled with a 3-D scan. Results concerning a defined optimal screw positioning and drill failures attempts were done by another independent surgeon.

Results: All 3-D scans were done without complications. The multiplanar reconstructions allowed a proper visualisation of the scaphoid in all cases. No additional movement of the fixed extremity occurred during the operation. No registration failures were detected. An optimally defined screw placement in the scaphoid was achieved in 9 cases. Two repeated drill attempts were necessary in one case, another case needed three drill attempts. The scaphoid was never perforated.

Discussion: Our development of a new immobilizing device for the complete hand and forearm allows proper use of 3-D fluoroscopy based navigation at the scaphoid including a placement of an osteosynthetic screw. Further movements of the hand or fingers are intraoperatively only possible after the definite drill placement has been performed.

The 3-D imaging modality allows a direct control of the reduction and screw placement intraoperatively. Our tests did not include simulated fracture conditions, a general use of our new technique can now only be implemented to non displaced fracture types, while clinical and further laboratory tests have to improve our findings for all types of scaphoid fractures.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_I | Pages 114 - 115
1 Mar 2009
Kendoff D Citak M Geerling J Stübig T Pearle A Krettek C Hüfner T
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Introduction: Intraoperative visualisation of anatomic joint line reduction and hardware placement is techniqually demanding, twodimensional c-arm imaging do not always allow acute decision making about remaining articular steps and hardware misplacement. Postoperatively identification of these failures may need extensive revison surgery and is costly. The new mobile Iso-C3D imaging device provides intraoperative multiplanar reconstructions, consequently immediate decision making becomes possible.

Materials and Methods: 250 different joint fractures were intraoperatively scanned with the Iso-C3D (ankle fractures; forefoot, calcaneus; pilon tibiale; tibia plateaus; wrists; spine; pelvic fractures). Multiplanar reconstructions were obtained from 100 fluoroscopic images the Iso-C-3D provides during one automatic scan protocol. Decisions about remaining articular steps and implant misplacements were compared with the knowledge of conventional c-arm images which were done before. If necessary directly intraoperative corrections were performed.

Results: In 43 clinical cases (17%) a direct intraoperative correction resulted in implant change (8%) or correction of reduction (9%), caused by articular steps > 2mm, screw or k-wire misplacement. In all those cases conventional c-arm images did not reveal the significant step or misplacement, correction decision were all based on the Iso-C3D imaging in those cases. In other (9%) significant steps or misplacements were identified in c-arm images and confirmed with the Iso-C3D images.

Discussion: With the new intraoperative three dimensional imaging device a direct introperative idenfication of remaining intraarticular steps and implant misplacements becomes possible. Missed steps and misplacements can be avoided and reduction of operative revison rates might result.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_I | Pages 126 - 126
1 Mar 2009
Kendoff D Hankemeier S Citak M Wang G Zheng G Hüfner T Krettek C
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Introduction: The main purpose of this study was to analyze the accuracy of conventional versus navigated open wedge corrective osteotomies of the proximal tibia. Furthermore, the intraoperative radiation dosage and the time of the operative procedure of both groups were compared.

Methods: 20 legs of 11 fresh cadaver (9 male, 2 female, age 35–71 years) were randomly assigned to conventional open wedge high tibial osteotomy (HTO) (n=10) or navigated open wedge HTO (n=10). Two legs had to be excluded because of pre-existing knee injuries. The aim of all corrective operations was to align the mechanical axis to pass through 80% of the tibial plateau (80% Fujisawa line), regardless of the preexisting alignment. The intraoperative mechanical axis was evaluated either by the cable technique for conventional HTO, or by a navigation module for navigated HTO (Medivision, Oberdorf/Switzerland). An angle fixed implant with interlocking screws (Tomofix, Mathys, Bettlach/Switzerland) was used to minimize postoperative loss of correction. Postoperatively, CT-scans were performed and the Fujisawaline and MPTA measured with a computer software for deformity analysis (Med-iCAD) The main outcome parameter was the accuracy of the correction, which was measured by the Fujisawa line. Secondary outcome parameters were the intraoperative radiation measured by the dose area product and the time of the operative procedure. For statistical analysis the standard deviation (S.D.) was calculated and the paired t-test applied.

Results: After conventional HTO, the mechanical axis was intersecting the Fujisawa line at 72.1% of the tibial plateau (range 60.4–82.4%, S.D. 7.2%). In contrast, after navigated HTO the tibia plateau was passed through 79.7% (range 75.5–85.8%, S.D. 3.3%). Thus, the accuracy of the correction was significantly higher after navigated HTO (p=0.020). In addition, the standard deviation of the corrections was significantly lower after navigated HTO (p=0.012). The medial proximal tibia angle (MPTA) increased 7.9° (range: 4.7–12.1°) after conventional HTO and 9.1° (range: 4.6–12.6°) after navigated HTO. The average dose area products of the conventional HTO (49.5 cGy/cm2, range 36.0–81.2 cGy/cm2) and navigated HTO (42.8 cGy/cm2, range 28.3–58.1 cGy/cm2) were comparable (p=0.231). However, navigated HTO elongated the operation time significantly (navigated HTO: 82 min, range 55–98 min; conventional HTO: 59 min, range 47–73 min) (p< 0.001).

Conclusion: Continuous three-dimensional imaging of the axis and of intraoperative tools with the a navigation module significantly improves the accuracy of open wedge osteotomies of the proximal tibia. Prospective clinical studies will show whether the results of this cadaver study can be transferred to the regular clinical use.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_III | Pages 552 - 552
1 Aug 2008
Board TN Kendoff D Krettek C Hüfner T
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Introduction: Movement of the limb during computer aided arthroplasty may cause soft tissue impingement on the reference marker(RM) and consequently alter the spatial relationship between RM and bone with resulting inaccuracies in navigation. The purpose of this study was to investigate the effect of different degrees of soft tissue dissection on the stability of reference markers during limb movement.

Methods: The stability of both one- and two-pin RM systems inserted using three different levels of soft-tissue dissection was analysed in relation to a super-stable RM in fresh cadaver lower limbs. The spatial relationship of the two RMs was analysed using the VectorVision® system (BrainLAB, Germany) during multiple repetitions of four predefined limb movements. All tests were done with RMs inserted in both the distal-anterior femur and distal-lateral femur.

Results: Analysis of movements of the test RM in relation to the super-stable RM showed that rotations of less than 0.15o and translations of less than 0.4mm occurred in most test combinations. The combination that showed the greatest instability was when a stab incision was used to insert a pin in the distal/lateral femur (translation 0.73mm+/−0.05, rotation 0.25o+/− 0.05)(p< 0.001). This instability occurred in both single and double pin RMs(p=0.21).

Conclusions: RM pins can be placed in the anterior distal femur through simple stab incisions without resulting in significant soft tissue impingement during limb movement. If pins are placed in the lateral distal femur through stab incisions, impingement may occur from the fascia lata. Release of the fascia lata 1cm either side of the pin prevents significant impingement. Wide skin incision is unnecessary in any location.


Orthopaedic Proceedings
Vol. 90-B, Issue SUPP_III | Pages 560 - 560
1 Aug 2008
Board T Kendoff D Krettek C Hüfner T
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Movement of the limb during computer aided arthroplasty may cause soft tissue impingement on the reference marker(RM) and consequently alter the spatial relationship between RM and bone with resulting inaccuracies in navigation. The purpose of this study was to investigate the effect of different degrees of soft tissue dissection on the stability of reference markers during limb movement.

The stability of both one- and two-pin RM systems inserted using three different levels of soft-tissue dissection was analysed in relation to a super-stable RM in fresh cadaver lower limbs. The spatial relationship of the two RMs was analysed using the VectorVision® system (BrainLAB, Germany) during multiple repetitions of four predefined limb movements. All tests were done with RMs inserted in both the distal-anterior femur and distal-lateral femur.

Analysis of movements of the test RM in relation to the super-stable RM showed that rotations of less than 0.15o and translations of less than 0.4mm occurred in most test combinations. The combination that showed the greatest instability was when a stab incision was used to insert a pin in the distal/lateral femur (translation 0.73mm+/− 0.05, rotation 0.25o+/− 0.05)(p< 0.001). This instability occurred in both single and double pin RMs(p=0.21).

RM pins can be placed in the anterior distal femur through simple stab incisions without resulting in significant soft tissue impingement during limb movement. If pins are placed in the lateral distal femur through stab incisions, impingement may occur from the fascia lata. Release of the fascia lata 1cm either side of the pin prevents significant impingement. Wide skin incision is unnecessary in any location.