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Biomedical subjects

Joachim Hassenpflug

Publications and source records attributed to Joachim Hassenpflug.

At least 19 recordsLinked to original sources
PubMed2006

The objective determination of compliance in treatment of adolescent idiopathic scoliosis with spinal orthoses.

STUDY DESIGN: Prospective study using a specifically developed microelectronic technology. OBJECTIVE: To establish new technical methods for the objective measurement of brace use without patient involvement. SUMMARY OF BACKGROUND DATA: Effectiveness of spinal bracing clearly depends on the compliance of the patient. For further improvement of spinal bracing, reliable data are needed concerning the brace use. Questionnaires or clinical judgment usually estimates subjectively the compliance, which ranges from 20% to 90%. So far, only 1 study with 10 patients has investigated the compliance by objective time-stamped logging in a daily life environment, showing an average brace use of 65%. METHODS: There were 9 female patients (age 14.2 years, standard deviation 1.5) with adolescent idiopathic scoliosis who took part in the study. Their thoracolumbosacral orthoses (Chêneau braces OT-Kiel, Kiel, Germany) were equipped with a specifically developed discrete data logger to record temperature at the skin-brace interface over a period of 5.4 weeks (standard deviation 3.1), at 2-minute date/time-stamped intervals. RESULTS: Brace use ranged from 4.2 to 22.4 hours per day (average 15.4 hours). Underlying the recommended bracing time of 23 hours, average compliance rate was 67.5% (range 19.0% to 97.1%). No patient reached a complete 23-hour bracing. Patients with poor compliance usually removed the brace during the daytime. The individual bracing pattern did not change over the course of an evaluation period, and the compliance can be estimated after 2 weeks. CONCLUSIONS: Long-term logging of temperature within a spinal orthosis is a reliable and simple way to measure objectively the compliance. Thus, comparison of full-time and part-time bracing is made possible on an objective basis. Furthermore, knowing the bracing pattern provides a better focus on other variables of spinal bracing, such as the force distribution within the brace. This knowledge may help to improve further the shape and effectiveness of bracing.

Adolescent↗
PubMed2006

Femoral artery constriction by norepinephrine is enhanced by methylprednisolone in a rat model.

BACKGROUND: Corticosteroids are associated with femoral head osteonecrosis and arterial hypertension. The patho-mechanism of femoral head osteonecrosis is often attributed to ischemia. The aim of this study was to investigate if corticosteroids directly constrict the femoral artery or if they have a permissive effect on norepinephrine and endothelin-1-induced vasoconstriction. METHODS: Femoral artery segments were harvested from twenty Wistar rats and mounted as ring preparations on a small-vessel myograph for the purpose of making isometric force measurements. For the norepinephrine study, twenty femoral artery segments from ten rats were stimulated cumulatively with norepinephrine before and after incubation with methylprednisolone (5 mug/mL). For the endothelin-1 study, forty femoral artery segments from ten rats were used. The four artery segments from each animal were randomized by pairs to either a corticosteroid treatment group (5 mug/mL methylprednisolone incubation, n = 20) or a control group (placebo incubation, n = 18, as two of the twenty control-group vessels did not meet protocol requirements). Isometric wall tension was plotted and quantified by the EC(50) (the plasma concentration of endothelin-1 required for obtaining 50% of maximal constriction in vivo). RESULTS: In the norepinephrine-stimulated group, incubation with methylprednisolone did not directly induce any vasoconstriction but did enhance norepinephrine-elicited vasoconstriction. The norepinephrine dose-response curve displayed a shift to the left after incubation with methylprednisolone. This shift was reflected by a significantly lower mean EC50 of 9.5 x 10(-7) M +/- 5.1 x 10(-7) M after methylprednisolone incubation compared with a mean of 2.5 x 10(-6) M +/- 1.1 x 10(-6) M before incubation (p < 0.005). In the endothelin-1-stimulated group, the endothelin-1 dose-response curve displayed a tendency toward stronger contraction in the vessels that were incubated with methylprednisolone, but this tendency did not reach significance. CONCLUSIONS: Incubation with methylprednisolone enhances norepinephrine-mediated contraction of the femoral artery in a rat model. CLINICAL RELEVANCE: Vasoconstriction of the vascular bed supplying the femoral head can diminish femoral head blood flow, and this may be a factor in the early pathogenesis of corticosteroid-associated femoral head osteonecrosis.

Animals↗
PubMed2005

The dimensional accuracy for preparation of the femoral cavity in HIP arthroplasty. A comparison between manual- and robot-assisted implantation of hip endoprosthesis stems in cadaver femurs.

INTRODUCTION: The aim of the study was to determine the precision of the preparation of the femoral cavity in cementless hip arthroplasty. We compared the bone-prosthesis interface after manual- and robot-assisted implantation of the stems. MATERIAL AND METHODS: After plastination the specimens were cut to slices of 2.5 mm and documented by microradiography. The interface between prosthesis and bone was measured digitally with a specially designed software. RESULTS: The manually implanted prostheses showed an average full-contact area of 60% and an average area of gaps of 40% with an average height of 0.8 mm. The robot-assisted implanted stems had a significantly higher bone-prosthesis interface area of 93% and gap areas of less than 0.2 mm depth. Destructions of the spongeous bone were seen with the manually implanted stems but not after robot-assisted implantations. There was one stem fracture during the manual preparation of a stem. Microradiographic examination showed microfractures in the region of the lesser trochanter in two femora after robot-assisted implantation CONCLUSION: The robot-assisted technique highly increased the fitting area at the bone-prosthesis interface. The main reason for the fractures might be the absence of a robot done marker for the ideal implantation height with the applied type of prosthesis.

Arthroplasty, Replacement, Hip↗
PubMed2005

Symptomatic calcification of the medial collateral ligament of the knee joint: a report about five cases.

Symptomatic calcifications of the rotator cuff tendons is well-known pathologic condition. However, pathologic calcifications may involve other structures of the locomotor system as well. We report about five patients (age 52-66 years) with a painful calcification at the proximal part of the medial collateral ligament of the knee joint. All five patients presented with load-dependent pain pretending meniscus symptoms, but manual valgus stress provoked severe pain at the medial side of the knee. Conventional X-ray examination showed a dense rounded deposit at the proximal part of the medial collateral ligament. Initially all patients were treated conservatively by needling and infiltration with a local anaesthetic. Open resection of the deposit was performed in four patients after unsuccessful conservative treatment. Postoperatively all patients were immediately free of pain. After a mean follow-up of 6 years (patient 1-4) (range=2.5-9.5 years), all patients were still free of pain. Histological evaluation of biopsies obtained during surgery showed nodular deposition of calcium at the collagen fibres, vascular proliferations and inflammative changes. Soft tissue calcifications have to be considered as a rare differential diagnosis in patients presenting with medial knee joint pain. Open resection reduces symptoms immediately. The histological changes seen were comparable to that reported about pathological tendon calcifications of the shoulder. Therefore, both conditions might be of the same aetiology.

Aged↗
PubMed2005

Human beta-defensin 3 mediates tissue remodeling processes in articular cartilage by increasing levels of metalloproteinases and reducing levels of their endogenous inhibitors.

OBJECTIVE: Beta-defensins are broad-spectrum antimicrobial peptides (APs) that are components of innate immunity. Recent investigations showed the induction of beta-defensins in synovial membranes of osteoarthritic (OA) joints and suggested that they have functions other than the ability to kill microbes. As a result of these findings, we undertook this study to investigate the production of human beta-defensin 3 (HBD-3) in OA cartilage and to determine its influence on chondrocyte function. METHODS: Healthy and OA cartilage were assessed for HBD-3 expression by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. HBD-3 expression in C28/I2 chondrocytes after administration of tumor necrosis factor alpha (TNFalpha) and interleukin-1 (IL-1) was determined by real-time RT-PCR and immunodot blot. Enzyme-linked immunosorbent assay experiments were used to study the effects of HBD-3 in cultured articular chondrocytes and in healthy and OA cartilage discs. Immunohistochemical analyses were performed to study the expression of mouse beta-defensins (MBDs) in OA cartilage of STR/Ort mice. RESULTS: HBD-3 was induced in OA cartilage without bacterial challenge. Cytokines involved in the pathogenesis of OA, namely, TNFalpha and IL-1, were strong inducers of HBD-3 in cultured chondrocytes. Application of the recombinant HBD-3 protein to cultured chondrocytes and cartilage discs resulted in increased production of cartilage-degrading matrix metalloproteinases and in down-regulation of their endogenous regulators, tissue inhibitors of metalloproteinases 1 and 2. Furthermore, STR/Ort mice, which are genetically predisposed to develop OA-like lesions in the knee joint, demonstrated an increased expression of MBDs 3 and 4 in cartilage compared with that in healthy animals. CONCLUSION: These findings widen our knowledge of the functional spectrum of APs and demonstrate that HBD-3 is a multifunctional AP with the ability to link host defense mechanisms and inflammation with tissue-remodeling processes in articular cartilage. Moreover, our data suggest that HBD-3 is an additional factor in the pathogenesis of OA.

Adult↗
PubMed2005

Expression and regulation of antimicrobial peptides in articular joints.

Articular joint infection is a surprisingly rare event considering the frequency of joint arthrocentesis and other invasive procedures applied to limb joints. This observation led us to the hypothesis that a local "chemical shield" in the form of antimicrobial proteins provides synovial membrane and articular cartilage with resistance to infection. We subsequently began a systematic analysis of in vitro and in vivo antimicrobially active proteins in healthy articular joints and in disease states such as pyogenic arthritis, rheumatoid arthritis, and osteoarthritis. An anatomical approach with systematic characterization combined with antimicrobial testing revealed expression and production of human antibiotic peptides and proteins. In this review, we focus on the most prominent antimicrobial proteins in articular joints, which we have identified as lysozyme, lactoferrin, secretory phospholipase A2, RNase 7, CAP37, the cathelicidin LL37, and especially the human beta-defensin-2 and -3 (HBD-2/-3). Activation pathways and possible antimicrobial functions are discussed and the involvement in non-antimicrobial processes such as tissue remodelling is also considered.

Cartilage, Articular↗
PubMed2005

Primary stability of hamstring graft fixation with biodegradable suspension versus interference screws.

PURPOSE: During the early postoperative period, the stability of the fixation of a hamstring graft to the bone tunnel is the primary factor in limiting rehabilitation. The aim of this study was to evaluate if the initial fixation strength of a new suspension screw is comparable to that of the biodegradable interference screw fixation technique in the hamstring reconstruction of the anterior cruciate ligament (ACL). TYPE OF STUDY: Experimental laboratory study. METHODS: We evaluated the initial fixation strength of a biodegradable poly-L-lactide/tri-calcium phosphate (PLLA/TCP) screw that suspended the graft in the bone tunnel and compared it with the strength of an interference screw for fixation of hamstring grafts in ACL reconstruction using bovine knees. Single-cycle and cyclic loading tests were performed using a materials testing machine. RESULTS: The suspension screw provided a significantly higher yield load and ultimate failure load than the interference screw. There was no significant difference in the stiffness of both techniques. The typical failure mode for the suspension screw was fracture of the screw and for the interference screw it was slippage of the graft past the screw. In cyclic testing, both methods of fixation ran out to 1,000 cycles up to 250 N with a mean displacement of 2.6 mm (range, 1.8 to 3.3 mm) for the suspension screw and 4.1 mm (range, 2.3 to 6.0 mm) for the interference screw. Only the grafts fixed with the suspension screw survived a protocol with 1,000 cycles up to 400 N. CONCLUSIONS: Our biomechanical data suggest that hamstring graft fixation using a biodegradable PLLA/TCP suspension screw provides an alternative to interference screw fixation. CLINICAL RELEVANCE: Hamstring graft fixation using a suspension screw provides a reasonable alternative to interference screw fixation.

Absorbable Implants↗
PubMed2004

[A long-term follow-up study of high tibial osteotomy in medial compartment osteoarthrosis].

OBJECTIVE: To observe long-term outcome of high tibial osteotomy (HTO) in treating the medial compartment osteoarthrosis of the knee. METHODS: A retrospective study was made between 1985 and 1996, of 194 patients (215 knees) who had HTO in medial compartment osteoarthritis at the Orthopaedic Hospital of Kiel University. RESULTS: One hundred and sixty-one knees were reviewed at an average follow-up of 7.5 years (range, 1.5 - 12 years). 97.3% good and excellent results up to two years postoperatively; 93.6% good and excellent results up to five years postoperatively; at over five years, 78.2% good and excellent. Nineteen (11.8%) knees had required conversion of their HTO to a total knee arthroplasty (TKA). The survive rate of HTO taking as TKA as an end point is 98.7% in 2 years; 95.0%, 5 years and 84.1%, 10 years. CONCLUSIONS: We believe that the high tibial osteotomy is one of good methods in treating the medial compartment osteoarthritis of the knee, overcorrection the femorotibial alignment is the key step of the operation. Postoperatively, there is a trend of the results to get worse with time and a part of the patients had been revised to total knee arthroplasty because of a poor result.

Adult↗
PubMed2004

Arthroscopic treatment of septic arthritis in a patient with posterior stabilized total knee arthroplasty.

We report on a case of arthroscopic treatment of septic arthritis of the knee in a 73-year-old woman with a posterior stabilized knee endoprosthesis. Six months after arthroplasty of the right knee joint because of osteoarthritis, the patient experienced an erysipelas of the right lower leg after a cat bite. Although given intravenous antibiotic therapy, the patient developed septic arthritis of the right knee. Pasteurella multocida could be identified as the causative organism. The joint infection was classified as stage I according to Gächter. Via arthroscopic joint debridement, partial synovialectomy, the use of continuous irrigation-suction drains, and intravenous antibiotic therapy, the empyema could be cured without removal of the total endoprosthesis of the right knee.

Aged↗
PubMed2004

Monarthritis of the pediatric knee joint: differential diagnosis after a thorn injury.

Foreign-body injury of the juvenile knee is frequently seen in the outpatient department. Arthroscopy is the most important diagnostic and therapeutic procedure along with radiographic examination in a case of typical history and clinical symptoms. In this case, an intra-articular thorn in a juvenile knee was not diagnosed at arthroscopy despite typical injury. Five months later, the boy developed knee pain and joint swelling. Bacterial infection of the knee and rheumatoid causes were excluded by serologic blood analysis several times at the children's hospital. Magnetic resonance imaging of the knee revealed an intra-articular foreign body. At a second arthroscopy, the thorn was removed and a hypertrophic plica with dependent cartilage damage of the medial femoral condyle was resected. At follow-up after 4 weeks, the boy was free of pain and swelling. After the first arthroscopy, persistent knee swelling and pain had to be taken as a hint of an intra-articular irritation. All arthroscopic surgeons should do a complete diagnostic examination of the affected joint in case of a foreign-body injury.

Arthritis↗
PubMed2004

Cyclic strain influences the expression of the vascular endothelial growth factor (VEGF) and the hypoxia inducible factor 1 alpha (HIF-1alpha) in tendon fibroblasts.

Neovascularization is involved in beneficial and detrimental processes of tendon pathology. We investigated the influence of repetitive motion on the expression of the most important angiogenic factor, the vascular endothelial growth factor (VEGF) in the 3T3 NIH fibroblast cell line and in cultures of rat Achilles tendon fibroblasts. Monolayers of subconfluently grown cells were stretched in rectangular silicone dishes with cyclic uniaxial movement. Strain was applied over 24 h varying the frequency (0.5-1 Hz). Fibroblasts (3T3 fibroblasts and rat Achilles tendon cultures) cultivated without the application of cyclic strain released measurable VEGF amounts into their culture supernatants. Cyclic stretching of the cells with a frequency of 1 Hz resulted in an increased expression of VEGF. A low frequency (0.5 Hz) reduced VEGF expression to control levels. RT PCR revealed VEGF 121 and VEGF 165 as the only splice forms that were induced by cyclic stretching. Western blot experiments could further show that cyclic stretching induced activation of the transcription factor HIF-1alpha. These results demonstrate that mechanical factors are involved in the regulation of VEGF expression in tendon tissue.

3T3 Cells↗
PubMed2004

Initial fixation strength of flexible all-inside meniscus suture anchors in comparison to conventional suture technique and rigid anchors: biomechanical evaluation of new meniscus refixation systems.

BACKGROUND: The newest generation of meniscus repair devices is designed to combine the benefits of the all-inside technique with the biomechanical properties of sutures. HYPOTHESIS: New flexible all-inside suture anchors have better fixation strength than rigid anchors, but there is no difference when compared to conventional horizontal and vertical mattress sutures. STUDY DESIGN: Controlled laboratory study. METHODS: In fresh-frozen bovine menisci, initial fixation strength, stiffness, and failure mode of different meniscus fixation techniques (FastT-Fix, RapidLoc, Meniscus Arrow, horizontal and vertical 2.0 Ethibond sutures) were evaluated in a computer-based materials testing machine at a rate of 12.5 mm/sec. RESULTS: The vertical and horizontal FastT-Fix suture anchors were the strongest devices with regard to pullout strength, with no significant difference compared to the vertical 2-0 Ethibond sutures. Horizontal sutures, Meniscus Arrow, and RapidLoc had significantly lower pullout strength. Vertical and horizontal FastT-Fix suture anchors showed significantly higher stiffness than the other devices. CONCLUSIONS: Biomechanical properties of flexible all-inside meniscus anchors (FastT-Fix) are comparable to conventional vertical suture techniques. Characteristics of the flexible RapidLoc are comparable to rigid anchors (Meniscus Arrow). CLINICAL RELEVANCE: From the biomechanical point of view, flexible all-inside meniscus refixation devices are an alternative to conventional suture techniques and rigid meniscus anchors.

Animals↗
PubMed2004

Minichromosome maintenance protein (MCM6) in low-grade chondrosarcoma: distinction from enchondroma and identification of progressive tumors.

The distinction between chondrosarcoma and enchondroma is difficult, and no reliable immunohistochemical or molecular methods are available. Differentiation is important because the therapeutic consequences range from radiologic followup to radical operation. We studied 17 chondrosarcomas (12 grade 1) and compared them with 14 enchondromas immunohistochemically by using the monoclonal antibodies Ki-MCM6 (minichromosome maintenance protein 6), Ki-S5 (Ki-67), and Ki-S2 (repp86), in addition to the established clinical criteria. In comparison with the other markers, Ki-MCM6 proved more effective at identifying proliferative activity in grade 1 chondrosarcomas. The MCM6 labeling index correlated with tumor grade and was significantly increased in grade 1 chondrosarcomas compared with enchondromas. The 5 cases of progressive chondrosarcoma also had a significantly higher MCM6 labeling index than the nonprogressive cases. Furthermore, by means of the MCM6 labeling index, many cases of progressive disease were recognized among those of uncertain malignant potential, justifying their classification as low-grade chondrosarcomas.

Adult↗
PubMed2004

The influence of oxygen and hydrostatic pressure on articular chondrocytes and adherent bone marrow cells in vitro.

Tissue engineering of articular cartilage from chondrocytes or stem cells is considered to be a potential aspect in the treatment of cartilage defects. In order to optimize culture conditions the influence of low oxygen tension (5%) - single or in combination with intermittent hydrostatic pressure (HP: 30/2 min on/off loading; 0.2 MPa) - on the biosynthetic activity (sulfate and proline incorporation) of human osteoarthritic chondrocytes cultured on collagen I/III membranes was investigated. Additionally, chondrogenesis from high density or monolayer cultures of bovine adherent bone marrow cells (aBMC) with and without chondrogenic medium supplements (CM) was analyzed by RT-PCR (mRNA expression of aggrecan and collagen type II). We could show that low oxygen tension increases significantly the biosynthesis of collagen I/III membrane-associated chondrocytes and even higher under co-stimulation with HP. While there is no chondrogenesis in monolayer cultures, CM induces expression of cartilage matrix molecules in high density cultures of aBMC which is even increased under the influence of low oxygen tension. Both, low oxygen tension and HP without CM are alone not sufficient stimuli for chondrogenesis. It can be concluded that low oxygen tension and HP might be useful tools in cartilage tissue engineering and that these physico-chemical factors promote but do not induce chondrogenesis under the given conditions.

Animals↗
PubMed2003

A new rigid biodegradable anchor for meniscus refixation: biomechanical evaluation.

All-inside repair devices have been developed to overcome the disadvantages of conventional suture techniques (such as vein and nerve damage and increased OR time). The Contour Meniscus Arrow is a second generation of the first biodegradable all-inside implant, the Meniscus Arrow. The aim of this study was to compare the biomechanical properties of the Contour Meniscus Arrow to the first-generation Meniscus Arrow and vertical or horizontal suture techniques. In fresh frozen bovine menisci, initial fixation strength, stiffness and failure mode of four different meniscus refixation techniques (Meniscus Arrow, Contour Meniscus Arrow, vertical and horizontal 2-0 Ethibond suture techniques) were evaluated in a computer-based material-testing machine at a rate of 12.5 mm/s. Vertical meniscus sutures showed the highest initial fixation strength, followed by the horizontal suture technique and the Contour Arrow. The Meniscus Arrow showed inferior pull-out strength. Subjecting the different refixation techniques to cyclic testing decreased the fixation strength in all groups. The modified Meniscus Anchor (Contour Arrow) provides biomechanical properties that are superior (pull-out strength) or similar (stiffness) compared to the first biodegradable all-inside implant, the Meniscus Arrow. The pull-out strength of the Contour Arrow was comparable to the pull-out strength reported for horizontal meniscus sutures in the literature. These biomechanical characteristics of this new implant justify clinical use.

Absorbable Implants↗
PubMed2003

Intra-articular ganglion cysts of the cruciate ligaments: case report and review of the literature.

BACKGROUND: A ganglion can arise as a cystic lesion from a tendon sheath or a joint capsule and contain a glassy, clear, and jelly-like fluid. They can occur within muscles, menisci, and tendons. Intra-articular ganglion cysts of the knee joint are rare. We report on three ganglion cysts of the cruciate ligaments: Two were intercruciate, and one was located around the posterior cruciate ligament. METHODS: The clinical diagnosis was established using magnetic resonance imaging. All patients were treated successfully using arthroscopic debridement by basket punch and shaver. Subsequent histological examination confirmed the diagnosis. RESULTS: All three patients were asymptomatic at the postoperative follow-up of 16-36 months. CONCLUSION: A review of the literature reveals a controversial discussion about the clinical significance as well as the etiology of ganglion cysts arising from the cruciate ligaments. These case reports show that an intra-articular ganglion cyst of the cruciate ligaments is difficult to diagnose. A cyst does not necessarily have to be associated with specific clinical symptoms or a previous trauma. Preoperatively, MRI is essential when diagnosing ganglion cysts of the knee joint. An intra-articular ganglion cyst of the knee joint can be successfully treated by arthroscopy.

Adult↗
PubMed2003

Thromboembolic complication after arthroscopic shoulder surgery.

Thromboembolic complications after arthroscopic shoulder surgery are very unusual and need thorough investigation of the possible origin. In this case of venous pulmonary thromboembolism after arthroscopy of the shoulder, neither a hint of coagulopathy nor an anatomic abnormality could be found that explains this complication. Therefore, irritation of the subclavian vein caused by compression by the motor-driven shaver is probably one cause for our thromboembolic complication. Careful attention to positioning, fluid management, and use of traction, as well as an appreciation of shoulder anatomy to select portal placement will help decrease the common complications associated with shoulder arthroscopy. A further option to prevent thrombembolic complications in shoulder arthroscopy patients might be prophylaxis with a low-weight heparin in patients with risk factors. In conclusion, awareness of uncommon complications such as deep venous thrombosis and pulmonary embolism will help the orthpaedic surgeon promptly diagnose and treat these problems.

Anticoagulants↗