... 3 © Urban & Vogel 139 Endosonographische Darstellung seltener anorektaler Tumoren Justyna Swol-Ben, Gunther Sandmann, Hans-Jürgen Schlitt, Alois Fürst1 Zusammenfassung ... World J Surg 2000;24:437–43. 8. Jao SW, Beart RW Jr,... more
... 3 © Urban & Vogel 139 Endosonographische Darstellung seltener anorektaler Tumoren Justyna Swol-Ben, Gunther Sandmann, Hans-Jürgen Schlitt, Alois Fürst1 Zusammenfassung ... World J Surg 2000;24:437–43. 8. Jao SW, Beart RW Jr, Spencer RJ, et al. Retrorectal tumors. ...
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Einleitung: Bei der bisher üblichen bikortikalen Fixationstechnik mittels Endobutton zur Refixation distaler Bizepssehnenrupturen besteht das Risiko der iatrogenen Schädigung des N. interosseus posterior (PIN) beim Durchbohren der... more
Einleitung: Bei der bisher üblichen bikortikalen Fixationstechnik mittels Endobutton zur Refixation distaler Bizepssehnenrupturen besteht das Risiko der iatrogenen Schädigung des N. interosseus posterior (PIN) beim Durchbohren der posterioren Kortikalis an der Tuberositas radii. In der vorliegenden[for full text, please go to the a.m. URL]
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Purpose Angular stable implants reduced the complication rate in the treatment of humeral head fractures. But the failure rate is still high. To further reduce the risk of cut-out, cement augmentation of screws was introduced. A reason... more
Purpose Angular stable implants reduced the complication rate in the treatment of humeral head fractures. But the failure rate is still high. To further reduce the risk of cut-out, cement augmentation of screws was introduced. A reason for failure of plate osteosynthesis might be the extremely high stiffness of the screw-plate interface leading to a loss of reduction and cut-out of screws. A more homogeneous distribution of the forces on all screws may avoid secondary dislocation. We hypothesize that dynamic osteosynthesis minimizes screw loosening and results in a higher load to failure than standard locking screws. Methods Twelve paired human humerus specimens were analysed. A standardized three-part fracture model with a metaphyseal defect was simulated. Within each pair of humeri, one was fixed with a Philos plate and standard locking screws (LS), whereas the other humerus was fixed with a Philos plate and dynamic locking screws (DLS). A cyclic varus-bending test or a rotation t...
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Transforming growth factor β (TGF-β) is a critical regulator of bone density owing to its multiple effects on cell growth and differentiation. Recently, we have shown that TGF-β1 effectively blocks bone morphogenetic protein (BMP) induced... more
Transforming growth factor β (TGF-β) is a critical regulator of bone density owing to its multiple effects on cell growth and differentiation. Recently, we have shown that TGF-β1 effectively blocks bone morphogenetic protein (BMP) induced maturation of osteoblasts by upregulating histone deacetylase (HDAC) activity. The current study aimed at investigating the effect of rhTGF-β1 treatment on the expression of specific HDACs and their cellular effects, e.g., microtubule structures (primary cilia) and mechanosensation. Exposure to TGF-β1 most significantly induced expression of HDAC6 both on gene and protein level. Being most abundant in the cytoplasm HDAC6 effectively deacetylates microtubule structures. Thus, TGF-β1-induced expression of HDAC6 led to deformation and shortening of primary cilia as well as to reduced numbers of ciliated cells. Primary cilia are described to sense mechanical stimuli. Thus, fluid flow was applied to the cells, which stimulated osteoblast function (AP ac...
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Pathological blood platelet activation promotes thrombosis in cancer patients, but the specific substances involved are still under investigation. Tumor exudates have been described to contain lysophosphatidic acid (LPA), a known... more
Pathological blood platelet activation promotes thrombosis in cancer patients, but the specific substances involved are still under investigation. Tumor exudates have been described to contain lysophosphatidic acid (LPA), a known platelet-activating substance, and the concentration of mediators present in malignant ascites are constantly equilibrated with the concentration in plasma. We hypothesized that the ascites of cancer patients might activate platelets, and that this may be caused by LPA. Indeed, ascites samples from 15 different patients with cancer induced shape change and an increase of cytosolic Ca2+ of isolated platelets; both responses were cross-desensitized by lysophosphatidic acid (LPA), but not by other platelet stimuli. Moreover shape change, Ca2+ mobilization and aggregation induced by ascites could be completely blocked by pretreatment of platelets with specific LPA-receptor antagonists. Phospholipids were extracted from ascites, separated by thin layer chromatog...
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To detect concomitant intra-articular glenohumeral injuries, in acute displaced fractures of the lateral clavicle, initially missed due to unfeasible clinical evaluation of the acutely injured shoulder. All patients suffering from an... more
To detect concomitant intra-articular glenohumeral injuries, in acute displaced fractures of the lateral clavicle, initially missed due to unfeasible clinical evaluation of the acutely injured shoulder. All patients suffering from an acute displaced lateral clavicle fracture with indication to surgical treatment underwent diagnostic shoulder arthroscopy prior to open reduction and internal fixation. In case of therapy-relevant intra-articular glenohumeral injuries, subsequent surgical treatment was performed. Intra-articular injuries were found in 13 of 28 patients (46.4 %) with initially suspected isolated lateral clavicle fracture. Additional surgical treatment was performed in 8 of 28 cases (28.6 %). Superior labral anterior-posterior (SLAP) lesions were observed in 4 of 28 patients (14.3 %; SLAP II a: 1; II b: 1; III: 1; and IV: 1). Lesions of the pulley system were found in 3 of 28 patients (10.7 %; Habermeyer III°). One partial articular supraspinatus tendon avulsion lesion (3.6 %) and one lesion of the subscapularis tendon (3.6 %; Fox and Romeo II°) were observed. Traumatic concomitant glenohumeral injuries in lateral clavicle fractures seem to be more frequent than expected in general. Subsequent surgical treatment of these formerly missed but therapy-relevant injuries may increase functional outcome and reduce complication rate. IV.
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Pertrochanteric fractures are one of the most common injuries in the elderly and due to the demographic changes the incidence and importance of this fracture entity will even increase in the future. The dynamic hip screw (DHS) has been... more
Pertrochanteric fractures are one of the most common injuries in the elderly and due to the demographic changes the incidence and importance of this fracture entity will even increase in the future. The dynamic hip screw (DHS) has been used as the gold standard implant in the treatment of pertrochanteric femoral fractures for many years but recent studies have shown that cephalomedullary nails have some advantages. Due to the high incidence, operative treatment of these fractures is part of the standard repertoire of trauma surgeons and this article therefore provides an overview of existing knowledge and new trends in the treatment of pertrochanteric femoral fractures.
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Biological augmentation of rotator cuff repair is of growing interest to improve biomechanical properties and prevent re-tearing. But intraoperative single shot growth factor application appears not sufficient to provide healing support... more
Biological augmentation of rotator cuff repair is of growing interest to improve biomechanical properties and prevent re-tearing. But intraoperative single shot growth factor application appears not sufficient to provide healing support in the physiologic growth factor expression peaks. The purpose of this study was to establish a sustained release of granulocyte-colony stimulating factor (G-CSF) from injectable vesicular phospholipid gels (VPGs) in vitro and to examine biocompatibility and influence on histology and biomechanical behavior of G-CSF loaded VPGs in a chronic supraspinatus tear rat model. G-CSF loaded VPGs were produced by dual asymmetric centrifugation. In vitro the integrity, stability and release rate were analyzed. In vivo supraspinatus tendons of 60 rats were detached and after 3 weeks a transosseous refixation with G-CSF loaded VPGs augmentation (n = 15; control, placebo, 1 and 10 μg G-CSF/d) was performed. 6 weeks postoperatively the healing site was analyzed hi...
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Fractures of the medial clavicle third are rare injuries. Even in case of significant fracture displacement, their therapeutic management has been nonoperative. Recently, surgical intervention has become mandatory for displaced fractures... more
Fractures of the medial clavicle third are rare injuries. Even in case of significant fracture displacement, their therapeutic management has been nonoperative. Recently, surgical intervention has become mandatory for displaced fractures types to prevent non-union and functional complaints, but the optimal operative strategy is being discussed controversially. We describe the case of a 63-year-old male patient with a significantly displaced medial clavicle fracture after failed conservative treatment resulting in restricted, painful shoulder function. The patient underwent open reduction and osteosynthesis with an anatomically precontoured locking compression plate (LCP). One year after surgery the patient is free of complaints and has returned to his preinjury activity level without any functional restrictions. As a not yet reported operative approach, anatomically preshaped locking plating seems to be an effective fixation method for displaced fractures of the medial clavicle thir...
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Chronic and atraumatic groin pain may be due to a variety of pathologies local to and distal from the hip joint. Aside from frequent entities, such as inguinal hernia, impingement of the iliopsoas muscle by the anterior rim of the... more
Chronic and atraumatic groin pain may be due to a variety of pathologies local to and distal from the hip joint. Aside from frequent entities, such as inguinal hernia, impingement of the iliopsoas muscle by the anterior rim of the acetabular component leading to a hematoma can be a potential cause after total hip replacement (THR). This article presents three cases of delayed groin pain after THR received due to osteoarthrosis of the hip joint several years prior to the onset of symptoms. In all three cases the patient suffered from chronic groin pain aggravated by active flexion without direct trauma. After thorough clinical, laboratory and radiological (ultrasound, x-ray, computed tomography) examination a hematoma of the iliopsoas muscle was detected. Furthermore, in all three cases the acetabular component appeared to be slightly malpositioned. Considering the least invasive procedure all cases were treated with an excavation of the hematoma. After recurrence the indications for...
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Our objective was to compare the quality and diagnostic performance of (18)F-fluoride PET/MR imaging with that of (18)F-fluoride PET/CT imaging in patients with foot pain of unclear cause. Twenty-two patients (9 men, 13 women; mean age,... more
Our objective was to compare the quality and diagnostic performance of (18)F-fluoride PET/MR imaging with that of (18)F-fluoride PET/CT imaging in patients with foot pain of unclear cause. Twenty-two patients (9 men, 13 women; mean age, 48 ± 18 y; range, 20-78 y) were prospectively included in this study and underwent a single-injection dual-imaging protocol with (18)F-fluoride PET/CT and PET/MR. At a minimum, the PET/MR protocol included T1-weighted spin echo and proton-density fat-saturated sequences in 2 planes each with simultaneous acquisition of PET over 20 min. PET/CT included a native isotropic (0.6 mm) diagnostic CT scan (80 kV, 165 mAs) and a subsequent PET scan (2 min per bed position). By consensus, 2 masked interpreters randomly assessed both PET datasets for image quality (3-point scale) and for the presence of focal lesions with increased (18)F-fluoride uptake (maximum of 4 lesions). For each dataset (PET/CT vs. PET/MR), the diagnoses were defined using both PET and a...
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ABSTRACT Introduction: Liposomal gene transfer is an effective therapeutic approach for the treatment of several pathophysiologic states. The purpose of the present study was to define whether the biological or chemical structure of a... more
ABSTRACT Introduction: Liposomal gene transfer is an effective therapeutic approach for the treatment of several pathophysiologic states. The purpose of the present study was to define whether the biological or chemical structure of a liposome influences cellular and biological regeneration in the skin and to determine by which mechanisms possible changes occur. Methods: Rats were inflicted a full-excision acute wound and divided into three groups to receive weekly subcutaneous injections of DMRIE liposomes plus the Lac-Z gene, or DOTAP/Chol liposomes plus the Lac Z gene, or saline. Planimetry, immunological assays, histological, and immunohistochemical "techniques were used to determine molecular mechanisms after gene transfer, protein expression, dermal, and epidermal regeneration. Results: DOTAP/Chol increased IGF-I and KGF protein concentration and caused concomitant cellular responses, e.g., by increasing IGFBP-3, p < 0.05. DOTAP/Chol liposomes improved epidermal regeneration by exhibiting the most rapid area and linear wound reepithelization compared to DMRIE or control, p < 0.001. DOTAP/Chol and DMRIE exerted promitogenic and anti-apoptotic effects on basal keratinocytes, p < 0.05. Dermal regeneration was improved in DOTAP/Chol treated animals by an increased collagen deposition and morphology, p < 0.001. DOTAP/Chol liposomes increased VEGF concentrations and thus neovascularization when compared with DMRIE and saline, p < 0.001. Summary: In the present study we showed that different liposomes have different effects on intracellular and biological responses based on its chemical and molecular structure. For gene transfer in acute wounds the administration of DOTAP/Chol liposomes appears to be beneficial. Acknowledgments: Clayton Foundation for Research
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The optimal treatment for proximal humeral fractures is controversial. Few data exist concerning the influence of the surgical approach on the outcome. The purpose of this study was to evaluate the clinical and radiological outcomes of... more
The optimal treatment for proximal humeral fractures is controversial. Few data exist concerning the influence of the surgical approach on the outcome. The purpose of this study was to evaluate the clinical and radiological outcomes of proximal humeral fractures treated with locking plate fixation through a deltopectoral vs an anterolateral deltoid-splitting approach. Of 86 patients who met the inclusion criteria, 70 were available for follow-up examination. Thirty-three patients were treated through a deltopectoral approach and 37 through an anterolateral deltoid-splitting approach. In all cases, open reduction and internal fixation with a PHILOS locking plate (Synthes, Umkirch, Germany) was performed. Clinical follow-up included evaluation of pain, shoulder mobility, and strength. Constant score and Disabilities of the Arm, Shoulder and Hand (DASH) score were assessed. A clinical neurological examination of the axillary nerve was also performed. Consolidation, reduction, and appearance of head necrosis were evaluated radiographically. After a mean follow-up of 33 months, Constant scores, DASH scores, and American Shoulder and Elbow Surgeons scores showed no significant differences between the groups. Clinical neurologic examination of the axillary nerve revealed no obvious damage to the nerve in either group. Deltopectoral and anterolateral detoid-splitting approaches for plate fixation of proximal humeral fractures are safe and provide similar clinical outcomes. The results of this study suggest that the approach can be chosen according to surgeon preference.
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Rapid healing of acute wounds, e.g., in burned patients, can be essential for survival. Oxidized regenerated cellulose/collagen (ORC/collagen) has been shown to improve wound healing of chronic wounds. The aim of the present study was to... more
Rapid healing of acute wounds, e.g., in burned patients, can be essential for survival. Oxidized regenerated cellulose/collagen (ORC/collagen) has been shown to improve wound healing of chronic wounds. The aim of the present study was to determine the effect of ORC/collagen on dermal and epidermal healing as well as growth factor concentration in acute wounds. Rats received a full-thickness excision wound and were treated with either ORC/collagen plus a hydrocolloid dressing or a hydrocolloid dressing alone. Planimetry, immunological assays, histological and immunohistochemical techniques were used to determine dermal and epidermal regeneration, protein concentration, and growth factor concentration. In addition, dermal vascularization and structure were determined. Wounds treated with ORC/collagen showed a significantly faster reepithelization than those treated with hydrocolloid alone, p < 0.05. This accelerated wound healing rate may be explained by significantly higher levels of platelet-derived growth factor, keratinocyte growth factor, insulin-like growth factor-I, and insulin-like growth factor binding protein-3 in the ORC/collagen group leading to antiapoptotic effects of skin cells, p < 0.05. There were no significant differences in collagen morphology or deposition, neo-angiogenesis, or vascular endothelial growth factor concentration between both treatment groups. We conclude that ORC/collagen matrix accelerates epidermal regeneration and locally increases growth factor concentrations. Increased reepithelization was associated with decreased skin cell apoptosis. Based on our data we hypothesize that the ORC/collagen matrix may also have beneficial effects on acute wounds in a clinical setting.
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Fractures of the tibial plateau are among the most severe injuries of the knee joint and are often the result of sports accidents, especially skiing accidents. Between January 2003 and March 2009, a total of 37 skiers with tibial plateau... more
Fractures of the tibial plateau are among the most severe injuries of the knee joint and are often the result of sports accidents, especially skiing accidents. Between January 2003 and March 2009, a total of 37 skiers with tibial plateau fractures were treated operatively at Klinikum rechts der Isar, Munich (level I trauma center); 28 patients with a minimum follow-up of 24 months were included in this study. Sporting activity was determined at the time of injury and at the time of survey at an average follow-up of 49.0 months postoperatively. At the time of the survey, 92.9% of all patients were engaged in sports; only 12 of the 28 patients returned to skiing. Of the competitive athletes (n = 5 at time of injury) no patient returned to competition. The number of different sporting activities declined significantly from 6.4 before the injury to 4.6 after the injury. The activity duration per week, being 5.0 hours at the time of injury, declined to 4.4 hours, although the difference is statistically not significant. The Lysholm score, 97.5 points before accident, illustrated a significant decline to 84.4 points. Activity levels according to the Tegner scale declined significantly from 6.1 to 4.7 after the tibial plateau fracture. The majority of patients could not return to their previous level of activity. For patients playing competitive sports, the tibial plateau fracture can be a career ender. Overall, 92.9% of the patients returned to sports, but we noticed a post-injury shift toward activities with less impact. Only 12 of the 28 (42.9%) skiers with tibial plateau fractures returned to skiing.
Research Interests: Treatment Outcome, Humans, Skiing, Female, Male, and 5 moreFracture Healing, Aged, Middle Aged, Adult, and Knee injuries
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This study was designed to present the novel technique of intramedullary cortical button fixation for distal biceps tendon repair via a single-limited anterior portal. To reattach the ruptured biceps tendon at the radial tuberosity, two... more
This study was designed to present the novel technique of intramedullary cortical button fixation for distal biceps tendon repair via a single-limited anterior portal. To reattach the ruptured biceps tendon at the radial tuberosity, two Bicepsbutton(™) (Arthrex, Naples, FL, USA) were intramedullary positioned to the anterior cortex. The surgical procedure is described in detail. This technique has been performed in a first series of 3 patients with acute distal biceps tendon ruptures. All patients were very satisfied after surgery and would undergo the same surgical procedure again. All patients regained full range of elbow motion with comparable strength of forearm supination and elbow flexion measured against the uninjured arm at 6 months of follow-up. No neurovascular complications have been occured. Double intramedullary cortical button repair has shown to be a safe and reliable fixation method for distal biceps tendon rupture in a small series of patients. Preliminary results are encouraging.
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Optimal surgical treatment of high-grade acromioclavicular joint dislocations is still controversially discussed. The purpose of the present controlled laboratory study was to evaluate whether a polydioxansulfate (PDS(®)) cord... more
Optimal surgical treatment of high-grade acromioclavicular joint dislocations is still controversially discussed. The purpose of the present controlled laboratory study was to evaluate whether a polydioxansulfate (PDS(®)) cord augmentation with separate reconstruction of the coracoclavicular (CC) ligaments and the acromioclavicular (AC) complex provides sufficient vertical stability in a biomechanical cadaver model. Twenty-four shoulders of fresh-frozen cadaveric specimen were tested. Cyclic loading and load to failure protocol was performed in vertical direction on 12 native AC joints and repeated after reconstruction. The reconstruction of the coracoclavicular ligament was performed using two CC PDS cerclages and an additional AC PDS cerclage. In static load testing for vertical force, the native AC joint complex measured 590.1 N (±95.8 N), elongation 13.4 mm (±2.1 mm) and stiffness 48.7 N/mm (±12.0 N/mm). The mean maximum load to failure in the reconstructed joints was 569.9 N (±97.9 N), elongation 18.8 mm (±4.7 mm) and stiffness 37.9 N/mm (±8.0 N/mm). During dynamic testing of the reconstructed AC joints, all specimens reached the critical elongation of 12.0 mm, defined as clinical failure between 200 and 300 N. The mean amount of repetitions at clinical failure was 305. A plastic deformation of the reconstructed specimens throughout cyclic loading could not be detected. The AC joint reconstruction with acromioclavicular and coracoclavicular PDS cord cerclages did not provide the aspired vertical stability in a cadaver model. Basic Science Study.
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The aim of this biomechanical in vitro study was to compare the novel technique of double intramedullary cortical button (DICB) fixation with the well-established method of suture anchor (SA) fixation for distal biceps tendon repair. A... more
The aim of this biomechanical in vitro study was to compare the novel technique of double intramedullary cortical button (DICB) fixation with the well-established method of suture anchor (SA) fixation for distal biceps tendon repair. A matched-pair analysis (24 human cadaveric radii) was performed with respect to cyclic loadings and failure strengths. Twelve specimens per group were cyclically loaded for 1,000 cycles at 1.5 Hz from 5 to 50 N and from 5 to 100 N, respectively. The tendon-bone displacement was optically analysed using the Image J Software (National Institute of Health). Afterwards, all specimens were pulled to failure. Maximum load to failure and mode of failure were recorded. All DICB constructs passed the cyclic loading test, whereas 4 of the 12 specimens within the SA group failed by anchor pull-out. Cyclic loading showed a mean tendon-bone displacement of 0.6 ± 1.4 mm for the DICB group and 1.4 ± 1.4 mm for the SA group (n.s.) after 1,000 cycles with 50 N, and a mean displacement of 2.1 ± 2.4 mm for the DICB group and 3.5 ± 3.7 mm for the SA group (n.s.) after 1,000 cycles with 100 N. Load to failure testing showed a mean failure load of 312 ± 76 N and a stiffness of 67.1 ± 11.7 N/mm for the DICB technique. The mean load to failure for the SA repair was 200 ± 120 N (n.s.) and the stiffness was 55.9 ± 21.3 N/mm (n.s.). The novel technique of DICB fixation showed small tendon-bone displacement during cyclic testing and reliable fixation strength to the bone in load to failure. Moreover, all DICB constructs passed cyclic loadings without failure. Based on the current findings, a more aggressive postoperative rehabilitation may be allowed for the DICB repair in clinical use.
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The purpose of the current study was to assess the clinical and radiological results after locking T-plate osteosynthesis with coracoclavicular augmentation of unstable and displaced distal clavicle fractures (Neer type 2). Thirty... more
The purpose of the current study was to assess the clinical and radiological results after locking T-plate osteosynthesis with coracoclavicular augmentation of unstable and displaced distal clavicle fractures (Neer type 2). Thirty patients, treated between January 2007 and January 2010 were followed up after a median follow-up time of 12.2 months (range 4.7-37.2). The Constant and DASH scores were used to evaluate the clinical outcome, and anterior-posterior and 30° cephalic view radiographs were performed to assess the bony healing. In all patients, the fracture healing was achieved within the first 10 weeks after surgery. All patients regained good or excellent shoulder function and returned to previous occupation and activity levels. The mean Constant and DASH scores were 92.3 points and 6.2 points, respectively. We did not observe any severe intra- or post-operative complication within the time of follow-up. The presented technique turned out to be a reliable method providing good results without showing severe complications. Case series, Level IV.
Research Interests: Adolescent, Humans, Female, Male, Clavicle, and 6 moreYoung Adult, Clinical Sciences, Aged, Middle Aged, Adult, and Biocompatible Materials
The purpose was to evaluate histological changes of the supraspinatus tendon (SSP) after refixation under continuous growth factor application over 20 days in comparison to the native healing process. In a chronic rat tendon tear model... more
The purpose was to evaluate histological changes of the supraspinatus tendon (SSP) after refixation under continuous growth factor application over 20 days in comparison to the native healing process. In a chronic rat tendon tear model (15 rats/group), a transosseous SSP refixation was performed and growth factors (control, G-CSF, b-FGF, combination) were continuously released into the subacromial space by an osmotic pump. Tendon healing was evaluated histologically by a modified MOVIN-Score, and Collagen I/III content was determined by immunohistology at 6 weeks. A modified MOVIN sum score showed significant lower counts for G-CSF and b-FGF in comparison to the control group (p = 0.050/p = 0.027) and the combined group (p = 0.050/p = 0.043). Collagen III was significantly reduced in the combined group compared to the control group (p = 0.028). Collagen I showed no significant differences. The Collagen I/III ratio was nearly doubled for b-FGF and the combined group compared to the control. At the study endpoint, 33% of pump dislocations were detected. The continuous application of both isolated growth factors (G-CSF/b-FGF) achieved improved tendon-remodeling. However, the continuous application via an osmotic pump showed a relative high dislocation rate when applied in the rat model.
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Meniscus tears are frequent indications for arthroscopic evaluation which can result in partial or total meniscectomy. Allografts or synthetic meniscus scaffolds have been used with varying success to prevent early degenerative joint... more
Meniscus tears are frequent indications for arthroscopic evaluation which can result in partial or total meniscectomy. Allografts or synthetic meniscus scaffolds have been used with varying success to prevent early degenerative joint disease in these cases. Problems related to reduced initial and long-term stability, as well as immunological reactions prevent widespread clinical use so far. Therefore, the aim of this study was to develop a new construct for tissue engineering of the human meniscus based on an acellular meniscus allograft. Human menisci (n = 16) were collected and acellularized using the detergent sodium dodecyl sulfate as the main ingredient or left untreated as control group. These acellularized menisci were characterized biomechanically using a repetitive ball indentation test (Stiffness N/mm, residual force N, relative compression force N) and by histological (hematoxylin-eosin, phase-contrast) as well as immunohistochemical (collagen I, II, VI) investigation. The processed menisci histologically appeared cell-free and had biomechanical properties similar to the intact meniscus samples (p > 0.05). The collagen fiber arrangement was not altered, according to phase-contrast microscopy and immunohistochemical labeling. The removal of the immunogenic cell components combined with the preservation of the mechanically relevant parts of the extracellular matrix could make these scaffolds ideal implants for future tissue engineering of the meniscus.
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The objective of this retrospective study was to evaluate the functional results of distal biceps tendon repair using suture anchors via a single-incision approach. Forty-nine patients were re-examined at a mean follow-up of 44.2 ± 32.1... more
The objective of this retrospective study was to evaluate the functional results of distal biceps tendon repair using suture anchors via a single-incision approach. Forty-nine patients were re-examined at a mean follow-up of 44.2 ± 32.1 months (range, 12-119 months). Subjective and objective criteria included patient's satisfaction, active range of motion (ROM), maximum isometric strength in flexion (at 45° and 90°), and supination of both arms. Functional scoring included the Morrey elbow score (MES) and the QuickDASH. Furthermore, follow-up radiographs were performed. Eighty-six percent of patients were highly satisfied or satisfied with their outcome. Compared to contralateral, the active ROM of elbow flexion, extension, and pronation was not affected; however, supination was decreased by 3° (P < 0.001). The isometric maximum strengths showed significant deficits in all tested scenarios (at 45°, P = 0.002; at 90°, P < 0.001; for supination, P < 0.001). The MES and the QuickDASH were 97.2 ± 4.9 and 7.9 ± 13.9, respectively. Heterotopic ossifications (HO) were found in 39% of patients; however, with respect to scores and strength, no significant differences were seen compared to patients without HO. Moreover, four anchor failures were detected. Single-incision suture anchor repair provides high patient's satisfaction and good results with respect to ROM and functional scoring. Nevertheless, based on presented data, the patient has to be informed of postoperative HO and especially for supination strength weakness after surgery. Distal biceps tendon repair should be reserved for experienced upper extremity surgeons to avoid procedure-related complications.
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Fractures of the tibial plateau are among the most severe injuries of the knee joint and lead to advanced gonarthrosis if the reduction does not restore perfect joint congruency. Many different reduction techniques focusing on open... more
Fractures of the tibial plateau are among the most severe injuries of the knee joint and lead to advanced gonarthrosis if the reduction does not restore perfect joint congruency. Many different reduction techniques focusing on open surgical procedures have been described in the past. In this context we would like to introduce a novel technique which was first tested in a cadaver setup and has undergone its successful first clinical application. Since kyphoplasty demonstrated effective ways of anatomical correction in spine fractures, we adapted the inflatable instruments and used the balloon technique to reduce depressed fragments of the tibial plateau. The technique enabled us to restore a congruent cartilage surface and bone reduction. In this technique we see a useful new method to reduce depressed fractures of the tibial plateau with the advantages of low collateral damage as it is known from minimally invasive procedures.
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Research Interests: Gene Therapy, Wound Healing, Apoptosis, Biological Sciences, Lipids, and 20 moreCollagen, Cholesterol, Animals, Gene transfer techniques, Male, Liposomes, Fibroblast Growth Factor, Rats, Epithelial cells, Protein Expression, Protein Conformation, Molecular weight, Cell Proliferation, Growth Factor, Quaternary Ammonium Compounds, Wounds and Injuries, Chemical Structure, Gene Transfer, Molecular Structure, and Vascular Endothelial Growth Factor
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The purpose of this study was to biomechanically evaluate a new technique of intramedullary cortical button fixation for subpectoral biceps tenodesis and to compare it with the interference screw technique. We compared intramedullary... more
The purpose of this study was to biomechanically evaluate a new technique of intramedullary cortical button fixation for subpectoral biceps tenodesis and to compare it with the interference screw technique. We compared intramedullary unicortical button fixation (BicepsButton; Arthrex, Naples, FL) with interference screw fixation (Bio-Tenodesis screw; Arthrex) for subpectoral biceps tenodesis using 10 pairs of human cadaveric shoulders and ovine superficial digital flexor tendons. After computed tomography analysis, the specimens were mounted in a testing machine. Cyclic loading was performed (preload, 5 N; 5 to 70 N at 1.5 Hz for 500 cycles), recording the displacement of the tendon. Load to failure and stiffness were subsequently evaluated with a load-to-failure test (1 mm/s). Cyclic loading showed a displacement of 11.3 ± 2.8 mm for intramedullary cortical button fixation and 9 ± 1.7 mm for interference screw fixation (P = .112). All specimens within the cortical button group passed the cyclic loading test, whereas 3 of 10 specimens within the interference screw group failed by tendon slippage at the screw-tendon-bone interface after a mean of 252 cycles (P = .221). Load-to-failure testing showed a mean load to failure of 218.8 ± 40 N and stiffness of 27.2 ± 7.2 N/mm for the intramedullary cortical button technique. For the interference screw, the mean load to failure was 212.1 ± 28.3 N (P = .625) and stiffness was 40.4 ± 13 N/mm (P = .056). We could not find any major differences in load to failure when comparing the tested techniques for subpectoral biceps tenodesis. Intramedullary cortical button fixation showed no failure during cyclic testing. However, we found a 30% failure rate (3 of 10) for the interference screw fixation. Intramedullary cortical button fixation provides an alternative technique for subpectoral biceps tenodesis with comparable and, during cyclic loading, even superior biomechanical properties to interference screw fixation.
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The aim of the study was to develop a standardized rat model for chronic rotator cuff tears. Therefore, a time point of degenerative changes that shows comparable histological changes to the chronic tendon tears in humans had to be... more
The aim of the study was to develop a standardized rat model for chronic rotator cuff tears. Therefore, a time point of degenerative changes that shows comparable histological changes to the chronic tendon tears in humans had to be determined. The rat shoulder has already been described as a standardized model for investigation of the healing behavior in acute supraspinatus lesions. Little data exist about the possibility of generating a chronic rotator cuff lesion. We performed a complete detachment of the supraspinatus tendon in 45 Sprague-Dawley rats. After an interval of 3, 6 and 9 weeks (15 rats in each group), the macroscopic and histological changes were analyzed. The histological investigation included atrophy and fatty muscle degeneration, tendon degeneration and the grade of inflammatory changes. For evaluation of tendon degeneration, a modified MOVIN-Score was used. The contralateral shoulder provided as control group. Macroscopically the defect showed an increasing coverage with scar tissue over time with a complete closure in 73% after 9 weeks. The 3 week group showed the highest rate of persisting defects (80%). The atrophy of the supraspinatus muscle decreased from initial slight atrophy to a nearly normal muscle status in the 9 week group. Fatty infiltration was found in three animals per group regardless of the time interval after detachment. Tendon degeneration (modified MOVIN-Score) showed no significant difference between 3 and 6 weeks (p = 0.93) whereas after 9 weeks a significant increased degeneration was found (p < 0.01). In the early phase (3 and 6 weeks), inflammatory cells could be detected more frequently. The results show that a chronic tear of the human rotator cuff can be imitated in the rat model with some exclusion. The rapid self-healing response in the rat and the fatty infiltration of the human muscle are the main differences. However, tendon degeneration, inflammation and muscle atrophy combined with a persisting defect at 3 weeks after detachment are comparable to the chronic tendon tears in humans. This model can serve as a basis for further research in the field of rotator cuff repair for chronic lesions.
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Introduction Osteoporotic fractures in the elderly are often complicated by delayed union, pseudarthrosis or implant failure and are associated with considerable morbidity and prolonged reconvalescence. At present there is cumulating... more
Introduction Osteoporotic fractures in the elderly are often complicated by delayed union, pseudarthrosis or implant failure and are associated with considerable morbidity and prolonged reconvalescence. At present there is cumulating recommendation to treat this kind of fractures with angular stable implants. Case presentation Herein, we report on the successful definitive treatment of a displaced comminuted spiral-fracture of the distal humerus shaft in