Michael Raschke

Publications of Michael Raschke

• Reconstruction of the Posterior Oblique Ligament and the Posterior Cruciate Ligament in Knees With Posteromedial Instability.

  Authors: Andre Weimann, Imke Schatka, Mirco Herbort, Andrea Achtnich, Thore Zantop, Michael Raschke, Wolf Petersen

  Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association. 04/2012;

  PURPOSE: Posterior cruciate ligament (PCL) injuries are often associated with injuries of the posteromedial structures of the knee. The motivation for this study was the attempt to test differentPURPOSE: Posterior cruciate ligament (PCL) injuries are often associated with injuries of the posteromedial structures of the knee. The motivation for this study was the attempt to test different reconstruction techniques for the structures of the posteromedial corner in a biomechanical experiment. METHODS: Kinematic studies were carried out on 10 cadaveric knees exposed to a 134-N posterior tibial load, 10-Nm valgus torque, and 5-Nm internal torque at 0°, 30°, 60°, and 90° of flexion. The resulting posterior tibial translation (PTT) was determined using a robotic/universal force-moment sensor testing system for (1) intact knees, (2) PCL-deficient knees, (3) knees with deficiency of the PCL and the posteromedial structures, (4) knees with only the PCL reconstructed, (5) knees with the PCL and posterior oblique ligament (POL) reconstructed, and (6) knees with the PCL, medial collateral ligament (MCL), and POL reconstructed. Kinematic data were analyzed by a 2-factor repeated analysis of variance. RESULTS: When both the PCL and the posteromedial structures were cut, PTT increased significantly at all flexion grades under a posterior tibial load (P < .05). Reconstruction of only the PCL could not restore PTT at 0°, 30°, 60°, and 90° of flexion under loading conditions in a knee with combined injury of the PCL and the posteromedial structures (P > .05). Additional reconstruction of the POL improved PTT at all flexion angles in comparison with only the PCL-reconstructed knee. Reconstruction of the MCL had no significant effect on PTT. CONCLUSIONS: This study shows that reconstruction of the POL contributes significantly to the normalization of coupled PTT in knees with combined injury of the PCL and the posteromedial structures under valgus or internal rotational moment. The supplementary reconstruction of the MCL did not provide significant improvement in knee kinematics. CLINICAL RELEVANCE: The POL should be addressed in the patient with combined injuries of the PCL and the posteromedial structures.

• Biochemical markers of bone turnover in tibia fracture patients randomly assigned to growth hormone (GH) or placebo injections: Implications for detection of GH abuse.

  Authors: Thomas Krusenstjerna-Hafstrøm, Michael Højby Rasmussen, Michael Raschke, Shunmugam Govender, Jesper Madsen, Jens Sandahl Christiansen

  Growth hormone & IGF research : official journal of the Growth Hormone Research Society and the International IGF Research Society. 09/2011; 21(6):331-5.

  It has been argued that increased levels of bone remodelling markers are not suitable indicators of GH abuse, as bone injuries per se increase the expression levels of these markers. To investigateIt has been argued that increased levels of bone remodelling markers are not suitable indicators of GH abuse, as bone injuries per se increase the expression levels of these markers. To investigate the impact of a recovering tibia fracture on circulating bone markers in subjects receiving placebo or GH treatment. A randomised, double-blind, placebo-controlled trial of up to 16weeks GH treatment, followed by a 16-week washout. Subjects (406 adult males and females) with a tibia fracture were randomly allocated within three days after surgery, to either placebo or GH treatment (15, 30 or 60μg/kg daily) until fracture healing or 16weeks after treatment initiation. IGF-I, serum C-terminal telopeptide of type I collagen (CTX), osteocalcin (OST) and bone-specific alkaline phosphatase (BAP) were measured during and after treatment. Dose-dependent increases were observed in groups receiving GH, and mean levels in the highest GH dose group peaked at eight (IGF-I, CTX) or 12weeks (OST) after treatment initiation. Statistically significant differences between GH treatment and placebo were seen for IGF-I, CTX and OST in all GH dose groups throughout the treatment period, and persisted until eight (CTX) or 12 (OST) weeks after cessation of treatment. IGF-I, CTX and OST are suitable candidate markers of prolonged, illicit administration of GH. Furthermore, CTX and OST have potentials to serve as markers also after cessation of GH administration.

• A method to perform spinal motion analysis from functional X-ray images.

  Authors: Martin Schulze, Frank Trautwein, Thomas Vordemvenne, Michael Raschke, Frank Heuer

  Journal of biomechanics. 06/2011; 44(9):1740-6.

  Identifying spinal instability is an important aim for proper surgical treatment. Analysis of functional X-ray images delivers measurements of the range of motion (RoM) and the center of rotationIdentifying spinal instability is an important aim for proper surgical treatment. Analysis of functional X-ray images delivers measurements of the range of motion (RoM) and the center of rotation (CoR). In today's practice, CoR determination is often omitted, due to the lack of accurate methods. The aim of this work was to investigate the accuracy of a new analysis software (FXA™) based on an in vitro experiment. Six bovine spinal specimens (L3-4) were mounted in a robot (KR125, Kuka). CoRs were predefined by locking the robot actuator tool center point to the estimated position of the physiologic CoR and taking a baseline X-ray. Specimens were deflected to various RoM(preset) flexion/extension angles about the CoR(preset). Lateral functional radiographs were acquired and specimen movements were recorded using an optical motion tracking system (Optotrak Certus). RoM and CoR errors were calculated from presets for both methods. Prior to the experiment, the FXA™ software was verified with artificially generated images. For the artificial images, FXA™ yielded a mean RoM-error of 0.01 ± 0.03° (bias ± standard deviation). In the experiment, RoM-error of the FXA™-software (deviation from presets) was 0.04 ± 0.13°, and 0.10 ± 0.16° for the Optotrak, respectively. Both correlated with 0.998 (p < 0.001). For RoM < 1.0°, FXA™ determined CoR positions with a bias>20mm. This bias progressively decreased from RoM = 1° (bias = 6.0mm) to RoM = 9° (bias<1.5mm). Under the assumption that CoR location variances <5mm are clinically irrelevant on the lumbar spine, the FXA™ method can accurately determine CoRs for RoMs > 1°. Utilizing FXA™, polysegmental RoMs, CoRs and implant migration measurements could be performed in daily practice.

• Arthroscopic fixation of matrix-associated autologous chondrocyte implantation: importance of fixation pin angle on joint compression forces.

  Authors: Mirco Herbort, Sandra Zelle, Dieter Rosenbaum, Nani Osada, Michael Raschke, Wolf Petersen, Thore Zantop

  Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association. 06/2011; 27(6):809-16.

  The aim of the study was to investigate the effect of pin fixation perpendicular and 30° tilted to the matrix surface on the joint compression forces. In a porcine knee model, joint compressionThe aim of the study was to investigate the effect of pin fixation perpendicular and 30° tilted to the matrix surface on the joint compression forces. In a porcine knee model, joint compression forces were recorded with a digital pressure sensor above the medial meniscus and with axial compression of 100 N by use of a material testing machine. The forces were recorded for an intact femoral condyle, as well as a standardized cartilage defect of 25 × 20 mm, after matrix-associated autologous chondrocyte implantation (m-ACI) (BioSeed C; Biotissue Technologies, Freiburg, Germany), fixed by use of a conventional suture technique and pin fixation with a biodegradable pin perpendicular and 30° tilted to the matrix surface. In knees with cartilage defects, the peak compression forces (mean, 824 kPa) were significantly increased compared with the intact knee joint (564 kPa). After m-ACI implantation with a chondral suture (581.3 kPa) and perpendicular pin fixation, the joint compression forces of the cartilage defect were significantly decreased (630.7 kPa). There were no significant differences compared with the intact knee. After 30° tilted pin insertion, mean joint compression forces were significantly increased (1,740 kPa). This study shows that after chondral suture and perpendicular pin fixation, there are no increased compression forces in the knee joint in comparison to an intact knee. Thirty degree tilted pin insertion contributes to increased joint compression forces. A tilted insertion during pin fixation in m-ACI should be avoided because it may lead to increased joint compression forces, especially after cartilage defect lesions on the tibial side.

• Biomechanical evaluation of a single-row versus double-row repair for complete subscapularis tears.

  Authors: Mathias Wellmann, Philipp Wiebringhaus, Ina Lodde, Hazibullah Waizy, Christoph Becher, Michael Raschke, Wolf Petersen

  Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA. 09/2009;

  The purpose of the study was to compare a single-row repair and a double-row repair technique for the specific characteristics of a complete subscapularis lesion. Ten pairs of human cadavericThe purpose of the study was to compare a single-row repair and a double-row repair technique for the specific characteristics of a complete subscapularis lesion. Ten pairs of human cadaveric shoulder human shoulder specimens were tested for stiffness and ultimate tensile strength of the intact tendons in a load to failure protocol. After a complete subscapularis tear was provoked, the specimens were assigned to two treatment groups: single-row repair (1) and a double-row repair using a "suture bridge" technique (2). After repair cyclic loading a subsequent load to failure protocol was performed to determine the ultimate tensile load, the stiffness and the elongation behaviour of the reconstructions. The intact subscapularis tendons had a mean stiffness of 115 N/mm and a mean ultimate load of 720 N. The predominant failure mode of the intact tendons was a tear at the humeral insertion site (65%). The double-row technique restored 48% of the ultimate load of the intact tendons (332 N), while the single-row technique revealed a significantly lower ultimate load of 244 N (P = 0.001). In terms of the stiffness, the double-row technique showed a mean stiffness of 81 N/mm which is significantly higher compared to the stiffness of the single-row repairs of 55 N/mm (P = 0.001). The double-row technique has been shown to be stronger and stiffer when compared to a conventional single-row repair. Therefore, this technique is recommended from a biomechanical point of view irrespectively if performed by an open or arthroscopic approach.

• Distraction Osteogenesis Enhances Remodeling of Remote Bones of the Skeleton: A Pilot Study.

  Authors: Julia Funk, Gert Krummrey, Carsten Perka, Michael Raschke, Hermann Bail

  Clinical orthopaedics and related research. 06/2009;

  Bone injuries have a systemic influence on the remodeling of bone. This effect has not been examined concerning its extent and duration. We measured the systemic effect of distraction osteogenesis onBone injuries have a systemic influence on the remodeling of bone. This effect has not been examined concerning its extent and duration. We measured the systemic effect of distraction osteogenesis on the remodeling of bones of the axial skeleton by means of the mineral apposition rate and bone formation rate in an animal experiment. Distraction osteogenesis was performed on the tibiae of 24 mature Yucatan minipigs. After a 4-day latency period, the tibiae were distracted 2 mm/day for 10 days. The ensuing consolidation phase lasted 10 days. Three fluorescent labeling substances were applied intravenously: calcein green at the second postoperative day, tetracycline 1 day after the end of the distraction phase, and xylene orange 2 days before sacrifice. We prepared ground sections from the ninth right ribs. The mineral apposition rate and bone formation rate were measured histomorphometrically on labeled osteons. The median mineral apposition rate during distraction was 2.39 mum/day (2.12-2.62 mum/day), which was higher than the rate during consolidation (median, 1.62 mum/day; 1.54-1.84 mum/day). The median bone formation rate confirmed this result and was 840.51 mum(2)/day (744.20-1148.26 mum(2)/day) during distraction and 384.25 mum(2)/day (330.84-467.71 mum(2)/day) during consolidation. Thus, a short period of distraction osteogenesis appears to have an anabolic effect on the mineral apposition rate of remote cortical bone.

• Femoral bridge stability in double-bundle ACL reconstruction: impact of bridge width and different fixation techniques on the structural properties of the graft/femur complex.

  Authors: Ann-Kristin Lehmann, Nani Osada, Thore Zantop, Michael Raschke, Wolf Petersen

  Archives of orthopaedic and trauma surgery. 05/2009;

  BACKGROUND: The aim of this study was to evaluate the impact of different widths of the bony bridge between the femoral AM and PL bundle tunnel and different fixation techniques on the structuralBACKGROUND: The aim of this study was to evaluate the impact of different widths of the bony bridge between the femoral AM and PL bundle tunnel and different fixation techniques on the structural properties of the graft/femur complex in double-bundle ACL reconstructions. HYPOTHESIS: Double-bundle ACL reconstruction with a bony bridge between AM and PL bundle tunnel of 1 mm results in significantly lower structural properties of the graft/femur complex when compared to a bridge of 2 and 3 mm. Interference screw fixation significantly lowers the structural properties when compared to cortical fixation. STUDY DESIGN: Controlled laboratory study. METHODS: Double-bundle ACL reconstructions using different bridge widths (1 mm, 2 mm, and 3 mm bridge) were loaded to failure after a cyclic loading protocol (1,000 cycles 0-200 N) and the structural properties were compared to a single-bundle ACL reconstruction group (n = 10 in each group). The structural properties of using a cortical button fixation were then compared to interference screw fixation (2 mm bridge). Statistical analyses were performed using a Mann-Whitney test (P < 0.05). RESULTS: Double-bundle reconstructions with cortical button fixation (1, 2, and 3 mm bridge) showed significantly higher ultimate failure loads and stiffness and significantly lower elongation compared to single-bundle reconstructions. Double-bundle ACL reconstructions with a 1 mm bridge showed significantly reduced structural properties of the graft/femur complex compared to a 2 or 3 mm bridge. Aperture fixation led to significantly lower ultimate loads when compared to cortical fixation. CONCLUSION: The bony bridge between the two femoral tunnels in double-bundle ACL reconstructions influences the stability of the graft/femur complex. Aperture fixation using interference screws shows inferior results when compared to cortical fixation. CLINICAL RELEVANCE: The results suggest that the indication for anatomical ACL reconstruction may include the size of the lateral femoral condyle. In small knees, a second femoral tunnel may be difficult to locate with a minimum bridge width of 2 mm.

• Coracoclavicular ligament reconstruction: biomechanical comparison of tendon graft repairs to a synthetic double bundle augmentation.

  Authors: Mathias Wellmann, Jan Kempka, Steffen Schanz, Thore Zantop, Hazibullah Waizy, Michael Raschke, Wolf Petersen

  Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA. 03/2009;

  For currently presented anatomical coracoclavicular ligament repairs issues such as autologous tendon graft versus synthetic suture augmentation and the optimum fixation strategies for both types ofFor currently presented anatomical coracoclavicular ligament repairs issues such as autologous tendon graft versus synthetic suture augmentation and the optimum fixation strategies for both types of reconstruction are not solved. The purpose of the study was to compare the biomechanical properties of different tendon graft repairs to the characteristics of a synthetic polyester augmentation. Four anatomical coracoclavicular ligament repairs were biomechanically tested: 5 mm coracoclavicular tendon loop with suture fixation, tendon loop with flip button fixation, tendon loop with interference screw fixation versus a double 1.0-mm polyester repair with flip button fixation. The biomechanical testing included cyclic superio-inferior loading and a subsequent load to failure protocol. The ultimate failure loads were significantly higher for the double polyester/flip button repair (927 N) compared to all tendon repair techniques (maximum 640 N). In contrast the stiffness level was higher for the tendon repairs compared to the polyester/flip button repair (68.7 N/mm) but strongly dependent on the fixation technique (interference screw 97.2 N/mm, flip button 84.9 N/mm, side to side suture 60.9 N/mm). A synthetic coracoclavicular augmentation using a polyester suture provides adequate structural properties compared to a tendon repair. Therefore the decision for a tendon graft should be made by the necessity of a biologic substrate rather than by the assumption of a biomechanical advantage.

• Rotational instability of the knee: internal tibial rotation under a simulated pivot shift test.

  Authors: Nadine Diermann, Tobias Schumacher, Steffen Schanz, Michael Raschke, Wolf Petersen, Thore Zantop

  Archives of orthopaedic and trauma surgery. 08/2008;

  INTRODUCTION: Recently, several publications investigated the rotational instability of the human knee joint under pivot shift examinations and reported the internal tibial rotation as measurementINTRODUCTION: Recently, several publications investigated the rotational instability of the human knee joint under pivot shift examinations and reported the internal tibial rotation as measurement for instrumented knee laxity measurements. We hypothesize that ACL deficiency leads to increased internal tibial rotation under a simulated pivot shift test. Furthermore, it was hypothesized that anatomic single bundle ACL reconstruction significantly reduces the internal tibial rotation under a simulated pivot shift test when compared to the ACL-deficient knee. METHODS: In seven human cadaveric knees, the kinematics of the intact knee, ACL-deficient knee, and anatomic single bundle ACL reconstructed knee were determined in response to a 134 N anterior tibial load and a combined rotatory load of 10 N m valgus and 4 N m internal tibial rotation using a robotic/UFS testing system. Statistical analyses were performed using a two-way ANOVA test. RESULTS: Single bundle ACL reconstruction reduced the anterior tibial translation under a simulated KT-1000 test significantly compared to the ACL-deficient knee (P < 0.05). After reconstruction, there was a statistical significant difference to the intact knee at 30 degrees of knee flexion. Under a simulated pivot shift test, anatomic single bundle ACL reconstruction could restore the intact knee kinematics. Internal tibial rotation under a simulated pivot shift showed no significant difference in the ACL-intact, ACL-deficient and ACL-reconstructed knee. CONCLUSION: In conclusion, ACL deficiency does not increase the internal tibial rotation under a simulated pivot shift test. For objective measurements of the rotational instability of the knee using instrumented knee laxity devices under pivot shift mechanisms, the anterior tibial translation should be rather evaluated than the internal tibial rotation.

• The role of the posterior oblique ligament in controlling posterior tibial translation in the posterior cruciate ligament-deficient knee.

  Authors: Wolf Petersen, Svenja Loerch, Steffen Schanz, Michael Raschke, Thore Zantop

  The American journal of sports medicine. 03/2008; 36(3):495-501.

  BACKGROUND: Posterior cruciate ligament injuries are often associated with injuries to other structures. The role of the posteromedial structures of the knee in these injuries has received littleBACKGROUND: Posterior cruciate ligament injuries are often associated with injuries to other structures. The role of the posteromedial structures of the knee in these injuries has received little attention. HYPOTHESIS: The posterior oblique ligament is an important restraint to posterior tibial translation in the posterior cruciate ligament-deficient knee. STUDY DESIGN: Controlled laboratory study. METHODS: Kinematic studies were performed on 10 cadaveric knees to test 3 external loading conditions at 0 degrees , 30 degrees , 60 degrees , and 90 degrees of flexion (134 N posterior tibial load, 10 N x m valgus rotation, and 5 N x m internal rotation). Resulting posterior tibial translation was determined by using a robotic/universal force-moment sensor testing system for (1) intact, (2) posterior cruciate ligament-deficient, (3) posterior cruciate ligament/superficial medial collateral ligament-deficient, (4) posterior cruciate ligament/superficial medial collateral ligament/deep medial collateral ligament/posterior oblique ligament-deficient, and (5) posterior cruciate ligament/superficial medial collateral ligament/deep medial collateral ligament/posterior oblique ligament/posteromedial capsule-deficient knee. RESULTS: When both the superficial medial collateral ligament and deep medial collateral ligament were cut in the posterior cruciate ligament-deficient knee, posterior tibial translation did not increase significantly at any flexion grade under all external loading conditions (P > .05). Additional cutting of the posterior oblique ligament increased posterior tibial translation significantly at 0 degrees , 30 degrees , 60 degrees , and 90 degrees of flexion under posterior tibial load and at all flexion angles tested under valgus or internal tibial load (P < .05). Additional cutting of the posteromedial capsule increased posterior tibial translation only at 0 degrees and 30 degrees in response to a valgus and internal tibial load (P < .05). CONCLUSION: The posterior oblique ligament and posteromedial capsule have a significant role in the prevention of additional posterior tibial translation in the knee with posterior cruciate ligament injury. CLINICAL RELEVANCE: The posterior oblique ligament should be addressed in the patient with combined injuries to the posterior cruciate ligament and the posteromedial structures.

• Biomechanical comparison of the primary stability of suturing Achilles tendon rupture: a cadaver study of Bunnell and Kessler techniques under cyclic loading conditions.

  Authors: Mirco Herbort, Axel Haber, Thore Zantop, Georg Gosheger, Steffen Rosslenbroich, Michael Raschke, Wolf Petersen

  Archives of orthopaedic and trauma surgery. 03/2008;

  INTRODUCTION: Biomechanical studies investigating suture techniques for Achilles tendon repair used single load to failure tests in order to evaluate the maximal load capacity of the repairedINTRODUCTION: Biomechanical studies investigating suture techniques for Achilles tendon repair used single load to failure tests in order to evaluate the maximal load capacity of the repaired construct. During early rehabilitation the repair is repetitively loaded such as exercise or daily living activities like walking. Cyclic loading seems to duplicate the physiological loading conditions more closely than single cycle failure tests. Aim of this study was to test the most commonly used Achilles tendon repair techniques (Bunnell and Kessler repair) under cyclic loading conditions. MATERIALS AND METHODS: Following tenotomy fresh human cadaveric tendons were sutured either with the Bunnell or Kessler technique. After repair, cyclic loading tests were performed with a uniaxial biomechanical testing machine Lloyd LR-5K Plus. Both groups were sutured with 0.7 mm PDS. RESULTS: Except at maximum load we could not find significant differences between tendons sutured by Bunnell and Kessler techniques. During the cyclic testing there were no differences between both groups with respect to displacement. This applies also to the stiffness of the constructs, which we defined from the load to failure measurements. The failure modes in both groups differed; the tendons repaired by Kessler technique were cut by the tendons and in the Bunnell group the suture material tore in each specimen tested. CONCLUSION: In our study Bunnell and Kessler techniques showed similar biomechanical properties using the same suture material. The typical failure mode of the Bunnell technique shows potential to optimise biomechanical behavior by using stronger suture material.

• Initial fixation strength of a new hybrid technique for femoral ACL graft fixation: the bone wedge technique.

  Authors: Mirco Herbort, Andre Weimann, Thore Zantop, Michael Strobel, Michael Raschke, Wolf Petersen

  Archives of orthopaedic and trauma surgery. 12/2007; 127(9):769-75.

  BACKGROUND: Aperture fixation with interference screws matching the diameter of the tunnel is associated with the risk of graft laceration and graft rotation. HYPOTHESIS: A hybrid fixation techniqueBACKGROUND: Aperture fixation with interference screws matching the diameter of the tunnel is associated with the risk of graft laceration and graft rotation. HYPOTHESIS: A hybrid fixation technique (extracortical and aperture fixation) with undersized interference screw placed behind a bone wedge provides a higher fixation strength as aperture fixation with a screw alone matching the size of the tunnel. STUDY DESIGN: Experimental laboratory study. METHODS: We evaluated the initial fixation strength (single cycle and cyclic loading tests) of hybrid and interference screw aperture fixation using different sized interference screws in porcine knees. RESULTS: Analysis of yield load, maximum load and stiffness in the single cycle loading test showed no statistically significant differences for hybrid fixation with a 1 mm undersized screw and aperture fixation with a screw matching the size of the tunnel. The use of an undersized screw alone resulted in low fixation strength. CONCLUSION: The initial fixation strength of the hybrid technique with undersized screws is comparable to that of interference screw fixation matching the size. CLINICAL RELEVANCE: The new "bone wedge fixation" is an alternative for ACL graft fixation without the risk of graft laceration and graft rotation.

• Reducing the "killer turn" in posterior cruciate ligament reconstruction by fixation level and smoothing the tibial aperture.

  Authors: Andre Weimann, Alexandra Wolfert, Thore Zantop, Anne Kathleen Eggers, Michael Raschke, Wolf Petersen

  Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association. 11/2007; 23(10):1104-11.

  PURPOSE: The aim of this study was to evaluate the influence of the operative technique on reducing the so called "killer turn" at the tibial bone tunnel exit in posterior cruciate ligament (PCL)PURPOSE: The aim of this study was to evaluate the influence of the operative technique on reducing the so called "killer turn" at the tibial bone tunnel exit in posterior cruciate ligament (PCL) reconstruction. METHODS: We investigated the benefit of reducing the sharp edge of the tibial bone tunnel exit using a custom made rasp in combination with extracortical and aperture (interference screw) graft fixation. Grafts were fixed in a porcine tibia model. Ten reconstructions each (sharp and rounded edge) were cyclically loaded (2,000 times) between 50 and 150 N, and another 10 each were subjected to 2,000 cycles between 50 and 300 N force. The surviving PCL reconstructions were loaded to failure using a material testing machine. RESULTS: Being subjected to the sharp edge of the posterior tibia, 5 of 10 extracortical and 8 of 10 aperture fixed grafts survived cyclic loading between 50 and 150 N. All extracortical fixed and 8 of 10 aperture fixed grafts failed before 2,000 cycles when loaded between 50 and 300 N. Structural properties of grafts fixed with interference screw were statistically significant higher when compared to extracortical fixation. After rounding the sharp edge of the tunnel, all grafts survived cycles between 50 and 150 N and 6 out of 10 extracortical and 8 of 10 aperture fixed grafts survived 2,000 cycles between 50 and 300 N. CONCLUSIONS: The results of this study suggest that a rounded posterior aspect of the tunnel exit at the tibial tunnel exit leads to significant less graft damage when compared to the typical sharp edge of the bone tunnel exit ("killer turn"). Additionally, the results show that aperture fixation of soft tissue grafts in PCL reconstruction is superior when compared to an extracortical fixation site. CLINICAL RELEVANCE: Aperture fixation and a rounded tibial bone tunnel exit seem to be a reasonable alternative in PCL reconstruction.

• The effect of locally applied vascular endothelial growth factor on meniscus healing: gross and histological findings.

  Authors: Wolf Petersen, Thomas Pufe, Christian Stärke, Thomas Fuchs, Sebastian Kopf, Wolfram Neumann, Thore Zantop, Juergen Paletta, Michael Raschke, Roland Becker

  Archives of orthopaedic and trauma surgery. 06/2007; 127(4):235-40.

  INTRODUCTION: Tears in the peripheral part of the menisci have a better healing potential than tears in the central part, because the central two-thirds of the menisci are avascular. We hypothesizedINTRODUCTION: Tears in the peripheral part of the menisci have a better healing potential than tears in the central part, because the central two-thirds of the menisci are avascular. We hypothesized that healing of meniscus tears in the avascular zone can be promoted by the local application of the angiogenic factor vascular endothelial growth factor (VEGF). MATERIALS AND METHODS: A tear was created in the avascular zone of the medial meniscus in 18 merino sheep. The tear was then repaired with an uncoated suture (group 1), a suture coated with PDLLA (group 2), and by a suture coated with PDLLA/VEGF (group 3). RESULTS: After 6 weeks, we observed increased immunostaining for factor VIII in the VEGF-treated group 3. However, in this treatment group no meniscus healed completely. In the uncoated suture group and in the PDLLA-coated-suture group, partial healing was observed in three animals and complete healing in three animals, respectively. CONCLUSION: In this experiment the local application of VEGF via PDLLA-coated sutures did not promote meniscus healing. Growth factors might not always be a promising tool for tissue repair.

• Long-term results after primary microsurgical repair of ulnar and median nerve injuries. A comparison of common score systems.

  Authors: Thomas Vordemvenne, Martin Langer, Sabine Ochman, Michael Raschke, Marc Schult

  Clinical neurology and neurosurgery. 05/2007; 109(3):263-71.

  OBJECTIVE: The aim of this retrospective study was to analyze the long-term results of primary repair of median and ulnar nerve lesions. Clinical influence factors for nerve reconstruction wereOBJECTIVE: The aim of this retrospective study was to analyze the long-term results of primary repair of median and ulnar nerve lesions. Clinical influence factors for nerve reconstruction were investigated. Furthermore, current score systems were inquired and evaluated on their effectiveness to illustrate the success of repair. PATIENTS AND METHOD: Sixty-five patients with 71 lesions of the median and ulnar nerve were assessed on average 8.2 years after reconstruction. The results were classified according to the DASH (disability of arm, shoulder, and hand) Score, the Rosen's hand protocol and the Highet Scale. RESULTS: On average the patients regained 70% of their original hand function (evaluated by Rosen Score: median nerve 2.2/for ulnar nerve 1.92 out of 3.0). Although we noticed inferior motor recovery in ulnar nerve lesions, no significant differences between the overall results of both nerves were observed. Neither accompanying artery and flexor tendon injuries nor the suture technique influenced the recovery. The age of the patient was confirmed as an important influence factor. The results of the DASH Score, Rosen Score and Highet Score correlated significantly. CONCLUSION: For a sufficient outcome measurement we underline the importance of evaluation of patient's estimation of their impact on their activities of daily living. For this a combination of the functional Rosen Score and the DASH Score is suggested.

• Effects of growth hormone in patients with tibial fracture: a randomised, double-blind, placebo-controlled clinical trial.

  Authors: Michael Raschke, Michael Højby Rasmussen, Shunmugam Govender, David Segal, Mette Suntum, Jens Sandahl Christiansen

  European journal of endocrinology / European Federation of Endocrine Societies. 04/2007; 156(3):341-51.

  OBJECTIVE: Investigate whether intervention with GH after tibial fracture enhances fracture healing. DESIGN: Randomised, double-blind, placebo-controlled study in 406 patients (93 women, 313 men,OBJECTIVE: Investigate whether intervention with GH after tibial fracture enhances fracture healing. DESIGN: Randomised, double-blind, placebo-controlled study in 406 patients (93 women, 313 men, age: 18-64 years) with tibial fracture. METHODS: Patients were stratified by tibial fracture (open or closed) and allocated to placebo or GH treatment (15, 30 or 60 mug/kg daily, until clinically assessed healing or until 16 weeks post-surgery). Primary outcome was time from surgery until fracture healing and assessment of healing was done centrally and observer blinded. Patients reported for evaluation every 4 weeks until 24 weeks, and at 9 and 12 months. RESULTS: GH did not accelerate time to healing in the combined group of open and closed fractures. When separately analysing the closed and open fractures, a significant difference in time to healing was observed between treatment groups, exclusively in the closed fractures (P<0.05; subgroup analysis revealed that the 60 microg/kg group was significantly different from placebo). The relative risk of fracture healing for 60 microg/kg versus placebo during the 12 month was: all fractures, 1.16; 95% CI: (0.86; 1.57) (ns); closed fractures, 1.44; 95% CI: (1.01; 2.05; P<0.05); open fractures, 0.75; 95% CI: (0.42; 1.31) (ns). The estimated median number of days before fracture healing in closed fractures was 95 with 60 microg/kg versus 129 with placebo (95% CI: (94; 129) and (94; 249)) corresponding to approximately 26% decrease in healing time. CONCLUSIONS: In the overall group of open and closed tibial fractures, no significant enhancement of fracture healing was observed with GH, whereas in closed tibial fractures, GH accelerated healing significantly.

• Biomechanical evaluation of two techniques for double-bundle anterior cruciate ligament reconstruction: one tibial tunnel versus two tibial tunnels.

  Authors: Wolf Petersen, Henning Tretow, Andre Weimann, Mirco Herbort, Freddie H Fu, Michael Raschke, Thore Zantop

  The American journal of sports medicine. 03/2007; 35(2):228-34.

  BACKGROUND: This research was undertaken to determine whether there is a need for a second tibial tunnel in anatomic anterior cruciate ligament reconstruction. HYPOTHESIS: Anatomic two-bundleBACKGROUND: This research was undertaken to determine whether there is a need for a second tibial tunnel in anatomic anterior cruciate ligament reconstruction. HYPOTHESIS: Anatomic two-bundle reconstruction with two tibial tunnels restores knee anterior tibial translation in response to 134 N and to 5-N.m internal tibial torque combined with 10-N.m valgus torque more closely to normal than does double-bundle reconstruction with one tibial tunnel. STUDY DESIGN: Controlled laboratory study. METHODS: Ten cadaveric knees were subjected to a 134-N anterior tibial load at 0 degrees, 30 degrees, 60 degrees, and 90 degrees and to 5-N.m internal tibial torque and 10-N.m valgus torque at 15 degrees and 30 degrees. Resulting knee kinematics and in situ force in the anterior cruciate ligament or replacement graft were determined by using a robotic/universal force-moment sensor testing system for (1) intact, (2) anterior cruciate ligament-deficient, (3) double-bundle/one tibial tunnel, and (4) double-bundle/two tibial tunnels. RESULTS: Anterior tibial translation for the reconstruction with two tibial tunnels was significantly closer to that of the intact knee than was the reconstruction with one tibial tunnel at 0 degrees and 30 degrees of flexion (0 degrees = 3.82 vs 6.0 mm, P < .05; 30 degrees = 7.99 vs 11 mm, P < .05). The in situ force normalized to the intact anterior cruciate ligament for the reconstruction with two tibial tunnels was significantly higher than the in situ force of the reconstruction with one tibial tunnel (30 degrees = 89 vs 82 N, P < .05). With a combined rotatory load, the anterior tibial translation of specimens with a tibial two-tunnel technique was significantly lower than that of specimens with one tunnel (0 degrees = 5.7 vs 8.4 mm, P < .05; 30 degrees = 7.5 vs 9.5 mm, P < .05). CONCLUSIONS: Anatomic reconstruction with two tibial tunnels may produce a better biomechanical outcome, especially close to extension. CLINICAL RELEVANCE: At the time of initial fixation, there appears to be a small biomechanical advantage to the second tibial tunnel in the setting of two-bundle anterior cruciate ligament reconstruction.

• Influence of synovial fluid on human osteoblasts: an in vitro study.

  Authors: Thomas F Fuchs, Wolf Petersen, Thomas Vordemvenne, Richard Stange, Michael Raschke, Jürgen R J Paletta

  TheScientificWorldJournal. 02/2007; 7:2012-20.

  Osseous graft healing at the tendon bone interface after anterior cruciate ligament (ACL) reconstruction is unsatisfactory in 10-25%, depending on the evaluation criteria or the kind of graft usedOsseous graft healing at the tendon bone interface after anterior cruciate ligament (ACL) reconstruction is unsatisfactory in 10-25%, depending on the evaluation criteria or the kind of graft used for reconstruction. Mechanical as well as biological aspects are currently discussed. Since osteoblasts play an important role in the osseous integration of an ACL graft, we hypothesize that synovial fluid (SF), when entering the bone tunnel, has an inhibitory effect on osteoblasts. In order to verify this hypothesis, human osteoblasts (p3) were incubated in the presence of SF or partially purified SF. Proliferation was assayed using MTT or BrdU assay. Gene expression of osteoblast markers (alkaline phosphatase, collagen I, and osteocalcin) were determined by TaqMan analysis. In the control group, SF was exchanged by fetal calf serum (FCS). The results showed osteoblast proliferation in the presence of SF as well as in partially purified heat-pretreated synovial fluid. Native SF induced alkaline phosphatase and collagen I gene expression. No induction of the osteocalcin gene was observed in the experiment. These results were comparable to that obtained with FCS. These findings suggest that SF stimulated proliferation of osteoblasts in vitro. This effect is mediated, in part, by heat-stable components of SF. In addition, the expression of osteoblast marker genes alkaline phosphatase and collagen I, but not osteocalcin, was induced by SF. Therefore, problems associated with cruciate ligament reconstruction might be due to the inhibition of osteoblast differentiation. If so, this is not a specific attribute of SF, but also applies to serum.

• Prophylaxis and treatment of implant-related infections by antibiotic-coated implants: a review.

  Authors: Gerhard Schmidmaier, Martin Lucke, Britt Wildemann, Norbert P Haas, Michael Raschke

  Injury. 06/2006; 37 Suppl 2:S105-12.

  Implant-related infection is a feared complication in orthopedic and trauma surgery with tremendous consequences for the patient. To reduce this risk, administration of perioperative antibioticImplant-related infection is a feared complication in orthopedic and trauma surgery with tremendous consequences for the patient. To reduce this risk, administration of perioperative antibiotic prophylaxis is a routine procedure in orthopedic surgery. A local delivery system for antibiotics based on a polymer implant coating has been developed to optimize the prophylaxis. In an animal experiment, the efficacy of local prophylaxis of gentamicin was compared to a systemic single shot of gentamicin and to a combination of both administrations. The medullary cavities of rat tibiae were contaminated with Staphylococcus aureus and titanium K-wires were implanted into the medullary canals. For local antibiotic therapy, the implants were coated with poly(D,L-Lactide) (PDLLA) loaded with gentamicin. All the animals not treated with local and systemic application of the antibiotic developed osteomyelitis and all cultures of the implants tested positive for S. aureus. Onset of infection was prevented in 80-90% of animals treated with gentamicin-coated K-wires, with and without systemic prophylaxis. Gentamicin-coated intramedullary tibial nails are CE-certified for Europe and Canada and several patients have already been treated for implant-related infection. Up to now, eight patients with open tibia fractures have been treated with an unreamed tibial nail (UTN) coated with PDLLA and gentamicin. In the 1-year follow up, none of the patients developed an infection. A prospective randomized clinical documentation is currently in progress. So far, the results suggest that a local application of gentamicin from PDLLA-coated implants might support systemic antibiotic prophylaxis in preventing implant-associated osteomyelitis.

• Joint kinematics and in situ forces after single bundle PCL reconstruction: a graft placed at the center of the femoral attachment does not restore normal posterior laxity.

  Authors: Simon Lenschow, Thore Zantop, Andre Weimann, Thomas Lemburg, Michael Raschke, Michael Strobel, Wolf Petersen

  Archives of orthopaedic and trauma surgery. 05/2006; 126(4):253-9.

  INTRODUCTION: Femoral tunnel placement has a great influence on the clinical outcome after PCL reconstruction. MATERIALS AND METHODS: Using a robotic/universal force moment sensor (UFS) testingINTRODUCTION: Femoral tunnel placement has a great influence on the clinical outcome after PCL reconstruction. MATERIALS AND METHODS: Using a robotic/universal force moment sensor (UFS) testing system, we examined joint kinematics and in situ forces of human knees following soft-tissue single bundle PCL reconstruction fixed at the center of the femoral attachment. RESULTS: Posterior tibial translation significantly increased at all flexion angles after transsection of the posterior cruciate ligament (p<0.05). PCL reconstruction resulted in significantly less posterior tibial translation at all flexion angles when compared to the PCL deficient knee (p<0.05). The differences in the in situ force between the intact ligament and the reconstructed graft were statistical significant (p<0.05). CONCLUSION: Single bundle PCL reconstruction with a soft-tissue graft fixed at the center of the femoral attachment is able to reduce the posterior tibial translation significantly. However, it cannot restore kinematics of the intact knee and in situ forces of the intact PCL.