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Biomedical subjects

Ulrich Bosch

Publications and source records attributed to Ulrich Bosch.

15 recordsLinked to original sources
PubMed2006

Proprioception and EMG pattern after capsulolabral reconstruction in shoulder instability: a clinical and experimental study.

The anterior capsulolabral reconstruction according to JOBE [13] is a modification of the Bankart operation. The capsular shift is performed via a subscapularis-split approach avoiding any incision into the musculature. A total of 43 patients with posttraumatic, chronic anterior shoulder instability underwent surgery. All patients had at least four dislocations preoperatively. Thirty-five patients were examined after an average of 3.7 +/- 1.4 years. Twenty-nine (82.9%) of these patients were free of pain, with functional assessment showing a mean external rotation deficit of 4.1 degrees +/- 2.9 degrees without any further movement restrictions. On average, a Rowe-Score of 86.1 +/- 12.4 points and an ASES-Score of 93.3 +/- 8.4 were achieved. The reluxation rate was 7.7%. The study demonstrated that despite the good clinical results, only 69% of patients were able to return to their previous sports activity level. This special problem is in agreement with other similar studies [4, 18] so that this relevant fact was further addressed by determination of proprioception and electromyographic muscle activity. Postoperatively, in contrast to other studies [1, 21, 24], a persisting proprioceptive deficit as well as an altered EMG pattern was found together with a significant reduction in activity of the deltoideus muscle on the operated side. These results may explain the problem to achieve complete restitution of the function of the shoulder joint after capsulolabral reconstruction.

Adolescent↗
PubMed2006

[Percutaneous perforation of the posteromedial capsuloligamentous structures to avoid cartilaginous damage due to arthroscopic intervention at the medial meniscal posterior horn in narrow joints].

THE PROBLEM: Irreversible cartilaginous damage to the femur and tibia due to resection and suture instruments in arthroscopic surgery at the posterior horn of the medial meniscus in narrow knee joints or in the presence of contracted medial capsuloligamentous structures. THE SOLUTION: Enlargement of the medial joint space by repeated percutaneous perforation of the posteromedial capsuloligamentous structures under consistently applied valgus stress. SURGICAL TECHNIQUE: With the knee joint almost in full extension and with simultaneous, uniformly applied valgus stress, repeated percutaneous perforation of the posteromedial capsuloligamentous structures with a sharp-tipped cannula until perceptible enlargement of the medial joint compartment is achieved. POSTOPERATIVE MANAGEMENT AND RESULT: Uneventful healing of the posteromedial capsuloligamentous structures without the need for any special postoperative treatments.

Arthroscopes↗
PubMed2006

[Combined injury of the medial and lateral meniscus and the anterior cruciate ligament].

THE PROBLEM: Combined injury of the medial and lateral meniscus and the anterior cruciate ligament. THE SOLUTION: One-stage arthroscopic treatment of all injuries. Repair of the bucket-handle tears with sutures and arrow-shaped implants. SURGICAL TECHNIQUE: Arthroscopy of the knee joint, repositioning of the buckethandle tears of the medial and lateral menisci. Evaluation of the stability of the menisci without sutures, insertion of horizontal and vertical sutures through the menisci in inside-out technique, refixation of the posterior horns with arrow-shaped meniscus implants. Reconstruction of the anterior cruciate ligament with a patellar tendon transplant. Knotting of the suture loops through the menisci directly onto the capsule. RESULT: Stable knee joint capable of load bearing and without signs of irritation after 12 weeks with a range of motion of 0/0/130 degrees. Slight muscle deficit in the right thigh.

Adult↗
PubMed2004

Alpha-smooth muscle actin containing contractile fibroblastic cells in human knee arthrofibrosis tissue. Winner of the AGA-DonJoy Award 2003.

INTRODUCTION: Primary arthrofibrosis is of major concern after joint trauma or knee ligament surgery. The underlying mechanism in detail remains unclear. Highly differentiated fibroblastic cells, so-called myofibroblasts, express the actin isoform alpha-smooth muscle actin (ASMA) and have been found to play a major role in tissue contraction during wound healing and organ fibrosis. We therefore studied the expression of myofibroblasts in human primary knee arthrofibrosis tissue. MATERIALS AND METHODS: Tissue samples were taken from the infrapatellar fat pad and intercondylar region of nine patients who underwent revision surgery due to arthrofibrosis after anterior cruciate ligament (ACL) reconstruction (study group). Control tissue was taken from five patients who underwent primary ACL reconstruction (control group I) and from eight patients, who underwent second-look arthroscopy after primary ACL reconstruction (control group II). ASMA containing fibroblasts were immunostained with a monoclonal antibody. Histomorphometry was performed for total cell amount, ASMA containing fibroblasts, and vessel cross-sections. RESULTS: The arthrofibrosis group showed a tenfold higher amount of ASMA containing myofibroblasts (23.4% vs. 2.3%) than in control group I. There was a significantly higher total cell count and lower vessel density than in control group I. Control group II showed an upregulation of myofibroblasts almost five times that in control group I; nevertheless there was no evidence of scar formation or tissue fibrosis. CONCLUSIONS: Myofibroblasts are responsible for scar tissue contraction during wound healing. In arthrofibrosis tissue fibroblast contraction may be involved in tissue fibrosis and contraction with consecutive loss of motion. We found that myofibroblasts are upregulated in arthrofibrosis tissue. ACL reconstruction itself caused an up regulation of myofibroblast content. Nevertheless these patients did not show any clinical or histological signs of arthrofibrosis. Thus it is reasonable to assume that the ratio of myofibroblasts and total cell amount in connective tissue are responsible for the onset of arthrofibrosis. Address the expression of this highly differentiated cell type may therefore present a target for future therapeutic interventions.

Actins↗
PubMed2004

Late esophageal perforation complicating anterior cervical plate fixation in ankylosing spondylitis: a case report and review of the literature.

Esophageal perforation in ankylosing spondylitis (AS) is a rare complication in anterior cervical spine surgery and has not been reported before. A 50-year-old patient with AS developed incomplete tetraplegia after minimal trauma. C5 pedicle fracture was diagnosed and treated predominantly by physical therapy until neurological symptoms progressed. Cervical spine MRI showed C6/7 fracture and spinal cord compression. The patient underwent dorsal laminectomy, C5-7 anterior cervical fusion using allograft iliac crest and CASPAR-plate fixation. Delayed esophageal perforation appeared 10 months postoperatively when he came first to our hospital. He complained of dysphagia and developed acute dyspnea. Posterior stabilization with two plates was performed followed by removal of the ventral plate and screws. The esophageal laceration was sutured. The patient was treated with antibiotics and percutaneous endoscopic gastrostomy. Position of fracture and implants were accurate at 18 months postoperatively. The patient had persistent minor neurological deficits (Frankel D) at last follow-up. We conclude that esophageal perforation after anterior spinal fusion is a rare complication. Minor traumas in patients with AS are unstable and can result in significant spinal injury. Dorsoventral stabilization should be performed to avoid further complications.

Cervical Vertebrae↗
PubMed2004

Screening for arthrofibrosis after anterior cruciate ligament reconstruction: analysis of association with human leukocyte antigen.

PURPOSE: Arthrofibrosis represents a severe complication of trauma and reconstructive joint surgery because of generalized connective tissue proliferation resulting in painful joint stiffness. It often appears stereotypical in terms of its clinical and pathologic features, comprising excess deposition of extracellular matrix proteins such as collagen type I, III, and VI and proliferation of fibroblasts. However, trauma and surgery around joints does not always lead to fibrosis, suggesting a genetic predisposition. For a number of autoimmune diseases, strong associations have been described. The objective of the study was to investigate whether an association of HLA (human leukocyte antigen) with primary arthrofibrosis exists. TYPE OF STUDY: Retrospective cohort study. METHODS: Seventeen patients with primary arthrofibrosis after autologous anterior cruciate ligament (ACL) reconstruction were identified and clinically reviewed. Blood samples were taken, and DNA was isolated by column extraction method. DNA samples were typed for the loci HLA-A, -B, -C, -DRB1, and -DQB1. Results were compared with the frequencies of allelic groups as determined for the caucasoid population. RESULTS: HLA-Cw*07 was significantly less often found in the patient group than in the general population (P =.022). The opposite effect was seen for Cw*08, which was found in 17.6% of the patient group but only in 3.8% of the reference group (P =.045). A significant difference was also seen for DQB1*06, because 23.5% of the patients but 48.6% of the reference group possessed an allelic variant of this group (P =.048). However, according to the relatively small number of patients, a statistical bias cannot be excluded. CONCLUSIONS: A possible link may exist between arthrofibrosis and HLA-Cw*07- and DQB1*06-negative as well as Cw*08-positive individuals. Further investigation is necesessary to confirm or vitiate the possible association. LEVEL OF EVIDENCE: Level IV.

Adult↗
PubMed2003

Cyclic mechanical strain induces NO production in human patellar tendon fibroblasts--a possible role for remodelling and pathological transformation.

The mechanism by which tendon fibroblasts can detect strain forces and respond to them is fairly unknown. Nitric oxide (NO) is a messenger molecule that among others can respond to shear stress in endothelial cells. Therefore, it was investigated whether cyclic mechanical strain induces NO in vitro in human patellar tendon fibroblasts. Human patellar tendon fibroblasts were cultured from remnants of patellar tendon transplants after reconstructive surgery. Fibroblasts were cultured on elastic silicone dishes. The cells were longitudinally strained (5%, 1 Hz) for 15' or 60'. As a control, no strain was applied. The experiments were finished after 0', 5', 15', and 30'. NO was determined using the Griess reaction. 15' strain showed at 0' and 5' 200% activation, which thereafter at 15' and 30' returned to normal levels. 60' strain showed a biphasic pattern. At 5' and 30', NO levels were increased to 175%. At 15', NO measurement displayed 120% increased levels. Mechanical strain induces NO production by tendon fibroblasts. Therefore, NO produced by tendon fibroblasts, as a response to alteration in their mechanical microenvironment, could modulate fibroblast function. The results of our study suggests that strain-related adaptive changes may, at least in part, be controlled by a process in which strain-related NO production from the fibroblast network may play a pivotal role. Moreover, these are basic findings that are important for further unravelling pathophysiology of tendon diseases.

Adaptation, Biological↗
PubMed2003

Modulation of cell functions of human tendon fibroblasts by different repetitive cyclic mechanical stress patterns.

Mechanical stress is a factor that is thought to play an essential role in tissue generation and reparation processes. The aim of the present study was to investigate the influence of different repetitive cyclic longitudinal stress patterns on proliferation, apoptosis and expression of heat shock protein (HSP) 72. To perform this study, human tendon fibroblasts were seeded on flexible silicone dishes. After adherence to the dish, cells were longitudinally stressed with three different repetitive stress patterns having a frequency of 1 Hz and an amplitude of 5%. The proliferation and apoptosis rates were investigated 0, 6, 12 and 24 hours after application of cyclic mechanical longitudinal strain. Expression of HSP 72 was tested after 0, 2, 4 and 8 hours. Control cells were also grown on silicone dishes, but did not receive any stress. Stress patterns applied during one day resulted in a significant increase in proliferation and a slight increase in apoptosis. HSP 72 expression was rather unchanged. A stress pattern applied during two days resulted in a reduced proliferation and apoptosis rate whereas the expression of HSP 72 showed a significant increase. This study shows that different stress patterns result in different cellular reactions dependent on the strength of applied stress. Repetitive stress applied during one day stimulated proliferation and apoptosis in contrast to an extended stress duration. The latter induced an inhibition of proliferation and apoptosis probably through an increased HSP 72 activity. This may be related to an excess of applied stress. Our results may implicate future modulation techniques for tissue reparation and tissue engineering.

Annexin A5↗
PubMed2002

Cyclic mechanical stretching of human patellar tendon fibroblasts: activation of JNK and modulation of apoptosis.

Accelerated rehabilitation after tendon, ligament and bone injuries is widely accepted to avoid adverse effects of immobilization. However, progressive rehabilitation may also lead to an excessive inflammatory soft tissue response and often leads to structural and functional problems such as excessive scarring. The equivalent at the molecular/cellular level is in part the regulation of the sensitive homeostasis between proliferation and apoptosis. However, little attention has been paid to this aspect of tendon pathogenesis. This study investigated the response profile of human tendon fibroblasts in terms of apoptosis and anticipated alteration of Jun N-terminal kinase (JNK) activation to cyclic mechanical stretching. Human tendon fibroblasts of six patients were stretched for 15 or 60 min with 1 Hz and an elongation of 5%. Activation of stress-activated protein kinase (SAPK)/JNK was measured by western blot analysis. Apoptotic cells were determined in the stretched cells and in controls by annexin-V staining and detection by flow cytometry. Additionally DNA laddering was determined by ligation-mediated (LM) polymerase chain reaction (PCR). Application of 15 and 60 min stretch increased activation of SAPK/JNK at a maximum after 60 min. However, JNK activation after the longer stretch period 50% less than after the shorter stretch period (15 min). The apoptosis rate was correspondingly increased after short stretch application but not after longer stretch. This might be caused by an inactivation of the activated JNKs by cell protection mechanisms. The findings suggest that mechanical stretching directly activates intracellular signaling pathways, which in turn induce apoptosis. The longer stretch period resulted in a decreased apoptotic rate due to development of stress tolerance. This might be caused by heat-shock protein mediated suppression of JNK activation. This novel observation is an important issue, as defined mechanical stretching, depending on its duration, modulates apoptosis and thus affects tendon remodeling.

Adaptor Proteins, Signal Transducing↗
PubMed2002

Reduction and fixation of displaced intracapsular fractures of the proximal femur.

Intracapsular fractures of the femoral neck are one of the most common fractures in the elderly. The incidence of these fractures will increase significantly in the next decades as a result of increasing life expectancy. Although treatment of these fractures by closed or open reduction and internal fixation is standard in young patients, arthroplasty is the standard treatment in geriatric patients in most countries. Comorbidities of the patients and current socioeconomic changes in healthcare led to reconsideration of closed reduction and internal fixation of femoral neck fractures as an alternative treatment modality. With correct decision-making, proper reduction, and proper consideration of the biomechanical principle of three-point fixation, minimally invasive screw fixation of femoral neck fractures is a safe and inexpensive procedure even in elderly patients. The purpose of the current review was to give an overview of the history, current techniques and developments, results, limitations, and complications of closed reduction and internal fixation of intracapsular femoral neck fractures.

Aged↗
PubMedDate not supplied

Modulation of proliferation and differentiation of human bone marrow stromal cells by fibroblast growth factor 2: potential implications for tissue engineering of tendons and ligaments.

Bone marrow stromal cells (BMSCs) play a central role in the repair and regeneration of mesenchymal tissues. For tissue engineering of ligaments and tendons, both stimulation of cell proliferation and differentiation with increased expression of essential extracellular matrix proteins and cytoskeletal elements are desirable. This study analyzes the effect of low-dose (3 ng/mL) fibroblast growth factor 2 (FGF-2) and high-dose FGF-2 (30 ng/mL) on proliferation (bromodeoxyuridine content, spectrophotometry), differentiation (transcription of collagen I, collagen III, fibronectin, elastin, alpha-smooth muscle actin, and vimentin, reverse transcription-polymerase chain reaction, and cell density and apoptosis (annexin V, fluorescence-activated cell sorting) of human BMSCs, and compares the results with those of a control group without FGF-2. Low-dose FGF-2 triggered a biphasic BMSC response: on day 7, cell proliferation reached its maximum and was significantly higher compared with the other groups. On days 14 or 28, collagen I, collagen III, fibronectin, and alpha- smooth muscle actin mRNA expression was significantly enhanced in the presence of low-dose FGF-2. In contrast, high-dose FGF-2 did not stimulate differentiation or proliferation. Vimentin mRNA was expressed only in cultures with low-dose and high-dose FGF-2 after 14 and 28 days. Cell density was significantly higher in cultures with low-dose FGF-2 compared with the group with high-dose FGF-2 on days 7, 14, and 28. The apoptosis rate remained stable, at a rather high level, in all groups. Microscopic investigation of the cell cultures with low-dose FGF-2 showed more homogeneous, dense, fibroblast-like, spindle-shaped cells with long cell processes compared with cultures with high-dose, or no FGF-2. Low-dose FGF-2 may be useful for tissue engineering of ligaments and tendons by increasing BMSC proliferation and stimulating mRNA expression of specific extracellular matrix proteins and cytoskeletal elements.

Bone Marrow Cells↗
PubMedDate not supplied

Comparison of surgical repair or reconstruction of the cruciate ligaments versus nonsurgical treatment in patients with traumatic knee dislocations.

BACKGROUND: Studies of traumatic knee dislocations have failed to provide a consensus regarding the best method of treatment. PURPOSE: Our purpose was to evaluate the results after surgical repair or reconstruction versus nonsurgical treatment and to compare the influence of prognostic factors. STUDY DESIGN: Retrospective study. METHODS: Eighty-nine patients were treated for traumatic knee dislocation. Surgical repair or reconstruction of the cruciate ligaments was performed in 63 patients (repair, 49; reconstruction, 14). In 26 patients, nonsurgical treatment was undertaken. RESULTS: At an average follow-up of 8.2 years, the mean Lysholm and Tegner scores were 75 and 3.7, respectively. The outcome in the surgical group was better than in the nonsurgical group. The scores were higher in patients who were 40 years of age or younger, who had sports injuries rather than motor vehicle accident injuries, and who had undergone functional rehabilitation rather than immobilization. CONCLUSIONS: Surgical repair or reconstruction of the cruciate ligaments was superior to nonsurgical treatment. Functional rehabilitation was the most important positive prognostic factor. Surgical repair or reconstruction of the cruciate ligaments is mandatory to achieve sufficient stability for functional rehabilitation. In cases of cruciate ligament avulsion, repair with transosseous fixation is a reasonable alternative to reconstruction, provided that it is performed within 2 weeks of trauma.

Adolescent↗
PubMedDate not supplied

Femoral press-fit fixation of the hamstring tendons for anterior cruciate ligament reconstruction.

BACKGROUND: Press-fit fixation of patellar tendon-bone anterior cruciate ligament autografts is an interesting technique because no hardware is necessary. For hamstring tendon grafts, no biomechanical data exist of a press-fit procedure. HYPOTHESIS: Press-fit femoral fixation of hamstring tendons is mechanically equivalent to press-fit patellar tendon-bone fixation. STUDY DESIGN: Controlled laboratory study. METHODS: Patellar and hamstring tendons of 30 human cadavers (age, 53.8 +/- 18.0 years) were used. An outside-in press-fit fixation with a knot in the semitendinosus and gracilis tendons and an inside-out and outside-in fixation with the tendons wrapped around a bone block were compared with patellar tendon-bone press-fit fixation in 30 ovine femora. Constructs were cyclically strained and then loaded until failure. Maximum load to failure, stiffness, and elongation during failure testing and cyclical loading were investigated. RESULTS: The maximum load to failure was 561 +/- 309 N for the patellar tendon, 599 +/- 234 N for the semitendinosus/gracilis tendons knot construct, 678 +/- 231 for the semitendinosus/gracilis tendons bone construct inserted outside in, and 339 +/- 236 for the semitendinosus/gracilis tendons bone construct inserted inside out (inferior to the others; analysis of variance, Dunn test, P < .01). Stiffness of the constructs averaged 134 +/- 32 N/mm for the patellar tendon, 124 +/- 21 N/mm for the knot construct, 118 +/- 27 N/mm for the outside-in fixation, and 117 +/- 23 N/mm for inside-out fixation. Elongation during initial cyclical loading was 0.7 +/- 0.6 mm for the patellar tendon, 1.6 +/- 0.5 mm for the knot construct, 1.9 +/- 1.2 mm for the outside-in fixation, and 1.9 +/- 0.9 mm for the inside-out fixation (significantly larger for all semitendinosus/gracilis tendon techniques, P < .05). CONCLUSIONS: Failure loads for the semitendinosus/gracilis tendons bone construct inserted outside in and the semitendinosus/ gracilis tendons knot construct were within the confidence interval of the patellar tendon press-fit fixation. All semitendinosus/ gracilis tendon graft techniques exhibited larger elongation during initial cyclical loading than the patellar tendon graft. There was no difference in stiffness between all techniques. CLINICAL RELEVANCE: Two of the 3 hamstring press-fit fixation techniques showed loads to failure similar to the patellar tendon fixation. Preconditioning of the constructs is critical. These results must be interpreted with care because of high standard deviations.

Adolescent↗