Biomedical subjects

Wolf Petersen

Publications and source records attributed to Wolf Petersen.

At least 37 records · Page 2Linked to original sources

PubMed2005

A controlled prospective case control study of a prevention training program in female team handball players: the German experience.

BACKGROUND: Few authors have investigated the effectiveness of preventive intervention in European team handball. PURPOSE: The aim of the present study was to evaluate the effects of a prevention program on the incidence of injuries in female European team handball players. STUDY DESIGN: Prospective controlled study. METHODS: Ten female handball teams (134 players) took part in the prevention program (1. Information about injury mechanism, 2. Balance-board exercises, 3. Jump training) while 10 other teams (142 players) were instructed to train as usual. Over one season all injuries were documented weekly. RESULTS: Ankle sprain was the most frequent diagnosis in both groups with 11 ankle sprains in the control group and 7 ankle sprains in the intervention group (Odds ratio: 0.55, 95% confidence interval: 0.22-1.43). The knee was the second frequent injury site. In the control group 5 of all knee injuries were anterior cruciate ligament (ACL) ruptures (incidence: 0.21 per 1000 h) in comparison with one in the intervention group (incidence: 0.04 per 1000 h). Odds ratio was 0.17 with 95% confidence interval of 0.02-1.5. CONCLUSIONS: This study confirms that proprioceptive and neuromuscular training is appropriate for the prevention of knee and ankle injuries among female European team handball players.

Adult↗

PubMed2005

Locally applied angiogenic factors--a new therapeutic tool for meniscal repair.

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. The avascular status of the meniscus is maintained by the expression of antiangiogenic factors such as endostatin. The distribution of endostatin in the menisci correlates with the degree of vascularization. Endostatin immunostaining is strong in the avascular zone and reduced in the vascularized outer one-third. Endostatin interacts with signal transduction of the vascular endothelial growth factor (VEGF) by reducing VEGF-induced kinase (Erk1/2) phosphorylation. VEGF plays an important role in angiogenesis in fetal menisci and it is down-regulated in the adult meniscus. We hypothesized that healing of meniscal tears in the avascular zone can be promoted by the local application of the angiogenic factor VEGF. To evaluate this hypothesis 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). After 6 weeks we observed increased factor VIII immunostaining in the VEGF-treated group. However, in this treatment group (VEGF/PDLLA) no meniscus healed. 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. Factor VIII expression is normally restricted to vascular endothelial cells. In this study, however, single endothelial cells could be detected in the menisci of the VEGF/PDLLA group. This finding suggests that the application of VEGF might have stimulated proliferation of vascular endothelial cells but the application of VEGF was not successful in stimulating the more complex process of vasculogenesis. Further immunohistochemical examinations of the specimen have shown that in the VEGF/PDLLA group there is strong immunostaining against matrix metalloproteinase 13 (MMP-13). In vitro studies have shown that VEGF can stimulate chondrocytes to proliferate but also to express MMP-13 via HIF1-alpha induction. Since meniscal fibrochondrocytes express the VEGF receptor 2 (KDR) the induction of MMP expression might be another factor which inhibits healing despite increased angiogenesis. In conclusion, the local application of VEGF via PDLLA-coated sutures does not promote meniscal healing. A single growth factor might not always be a promising tool for the promotion of tissue repair. Further studies have to find out if growth factor combinations (VEGF and angiopoitin) might be more effective in stimulating vasculogenesis during meniscal healing.

Angiostatic Proteins↗

PubMed2005

The influence of biomechanical parameters on the expression of VEGF and endostatin in the bone and joint system.

Many degenerative processes in the skeletal system are induced by mechanical overload. Osteoarthritis and spontaneous tendon ruptures are two examples of mechanically influenced diseases. Incubator-housed compression apparatuses and cyclic strain chambers are adequate models to investigate the cellular processes. Recent studies have shown that growth factors are involved in the transduction pathways of mechanical overload leading to tissue degradation. Vascular endothelial growth factor (VEGF) is a dimerized, 45 kDa peptide that normally attracts endothelial cells in wound healing. VEGF can be detected in the superficial zone of the tibial plateau in osteoarthritic (OA) patients with degenerative changes but not in healthy articular cartilage. Blood vessels are only rarely observed in OA cartilage suggesting that there are other roles for VEGF in cartilage. VEGF is also detectable in ruptured but not in normal tendons. The mechanically induced expression of VEGF in avascular tissues like articular cartilage or fibrocartilage of contact areas from gliding tendons initiates degenerative processes. Chondrocytes from OA cartilage also express the VEGF receptor 2. In vitro assays have shown that VEGF binds the VEGFR-2 leading to a phosphorylation of MAP kinases (ERK1/2) with subsequent transcription factor accumulation (activator protein 1 = AP-1). One of the antagonists of VEGF is endostatin. Endostatin, a fragment of collagen type XVIII, is expressed in avascular tissues and has the potency to decrease VEGF induced effects (ERK1/2 phosphorylation). The increase in matrix metalloproteinase (MMP) production and the decrease in tissue inhibitor metalloproteinase (TIMP) synthesis is a result of the signal transduction cascade activation. MMPs participate in the degradation processes of osteoarthritis whereas TIMPs are inhibitors of the MMPs. Taken together mechanically induced VEGF is involved in the destruction and endostatin in the maintenance of avascular tissues of the bone and joint system.

Biomechanical Phenomena↗

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↗

PubMed2005

Cyclic loading comparison between biodegradable interference screw fixation and biodegradable double cross-pin fixation of human bone-patellar tendon-bone grafts.

PURPOSE: The aim of this study was to compare ultimate load, yield load, stiffness, and displacement after cyclic loading of a cross-pin technique and an interference screw technique for the fixation of bone-patellar tendon-bone (BPTB) grafts in anterior cruciate ligament (ACL) reconstruction. TYPE OF STUDY: Biomechanical in vitro study. METHODS: The devices tested were 2 2.7-mm biodegradable pins (RigidFix; Ethicon, Mitek Division, Norderstedt, Germany) and biodegradable interference screws (Absolute; Innovasive Devices, Marlborough, MA). Each device was used for the fixation of 10 8-mm, 9-mm, or 10-mm sized human BPTB grafts in tunnels drilled in bovine knees. Ultimate load, yield load, stiffness, and displacement after cyclic loading (1,000 cycles between 50 and 250 N) were then evaluated. RESULTS: All 8-mm grafts that were fixed with cross-pins failed after a mean of 124 cycles of load. The 9-mm and 10-mm grafts survived the cyclic loading protocol. Yield load and maximum load of the 10-mm groups (cross-pin and interference screw) were significantly higher than that of the 9-mm groups. There was no significant difference in maximum load, yield load, and stiffness between the cross-pin and interference screw fixation technique for 1 graft size. CONCLUSIONS: The biomechanical data suggest that femoral fixation of 9-mm and 10-mm BPTB grafts using 2.7-mm biodegradable cross-pins leads to primary stability that is comparable to that of biodegradable interference screws. Fixation of 8-mm BPTB grafts using 2.7-mm biodegradable cross-pins had poor results. CLINICAL RELEVANCE: The diameter of the bone block is the limiting factor for the final fixation strength and the cyclical survival when using cross-pins. We strongly recommend not using this technique for bone blocks smaller than 9 mm in diameter.

Absorbable Implants↗

PubMed2005

Cyclic testing of flexible all-inside meniscus suture anchors: biomechanical analysis.

BACKGROUND: Flexible meniscus repair devices are designed to combine the benefits of rigid all-inside meniscus anchors with the biomechanical properties of sutures. HYPOTHESIS: Stiffness and pull-out strength of flexible all-inside suture anchors and conventional sutures under cyclic loading conditions will be comparable. STUDY DESIGN: Controlled laboratory study. METHODS: In 50 fresh frozen bovine menisci, artificial meniscus lesions were repaired with different meniscus fixation techniques: horizontal and vertical FasT-Fix, RapidLoc, and horizontal and vertical 2-0 Ethibond sutures. The specimens were cycled 1000 times between 5 and 20 N and then loaded to failure. RESULTS: All devices survived the cyclic loading protocol. There was no significant difference in the displacement between all repair techniques tested (horizontal FasT-Fix, 6.23 mm; vertical FasT-Fix, 5.34 mm; RapidLoc, 6.84 mm; horizontal 2-0 Ethibond, 6.03 mm; vertical 2-0 Ethibond, 5.61 mm (P > .05). Vertical and horizontal FasT-Fix suture anchors had a significantly higher stiffness and pull-out strength (94.1 N and 80.8 N, respectively) than did horizontal sutures (50.2 N) and RapidLoc devices (30.3 N) (P > .05). CONCLUSIONS: In this study, flexible all-inside meniscus anchors (FasT-Fix) had higher pull-out strength than did conventional vertical suture techniques. Biomechanical characteristics of the flexible RapidLoc are comparable to those of horizontal sutures. CLINICAL RELEVANCE: Flexible all-inside meniscus repair devices are an alternative to conventional suture techniques.

Animals↗

PubMed2005

Mechanical comparison of two types of fixation for proximal first metatarsal crescentic osteotomy.

BACKGROUND: The proximal crescentic osteotomy is an effective technique for correcting a widened 1-2 intermetatarsal angle associated with moderate to severe hallux valgus deformities. However, postoperative dorsal malunion at the osteotomy site from loss of fixation has been reported. The purpose of this study was to evaluate the biomechanical characteristics of a new custom-designed plate and compare it to the traditional screw and Kirschner wire construct. METHODS: Twenty identical Sawbone (Pacific Research Laboratories, Vashon, WA) models were used for the study. A proximal crescentic osteotomy was done on each specimen, and 10 were secured with a dorsomedial plate (group I). The remaining 10 models were fixed with a screw and Kirschner wire combination (group II). Physiologic cyclical testing was done using a mechanical testing machine to evaluate dorsal displacement of the metatarsal. Load-to-failure testing was then done on each specimen to evaluate ultimate failure and stiffness of the constructs. Groups I and II were statistically compared using paired t-testing. RESULTS: The mean dorsal displacement of the first metatarsal head after 1000 cycles was 0.19 mm (SD = 0.09 mm) for group I and 0.28 mm (SD = 0.15) for group II, and the difference was not statistically significant (p = 0.08). Group I demonstrated statistically superior ultimate failure strength (95.2 N) and stiffness (26.8 N/mm) compared to group II (73.7 N, 19.4 N/mm). CONCLUSIONS: Based on Sawbone models, dorsal plate fixation of proximal crescentic osteotomy provides a stronger construct than the traditional screw and Kirschner wire construct. The clinical use of the specially-designed plate described in this study may lower the incidence of dorsal malunions that occur postoperatively and may decrease the occurrence of transfer metatarsalgia. Its application may be particularly helpful in patients with poor bone quality.

Biomechanical Phenomena↗

PubMed2004

Soft-tissue graft fixation in posterior cruciate ligament reconstruction: evaluation of the effect of tibial insertion site on joint kinematics and in situ forces using a robotic/UFS testing system.

INTRODUCTION: Surgical reconstruction of the posterior cruciate ligament (PCL) is recommended in acute injuries that result in severe tibial subluxation and instability. The surgical outcome level may be affected by the tibial fixation site. In response to a 110-N posterior tibial load, kinematics and in situ forces of anatomical soft-tissue graft fixation in single-bundle PCL reconstruction using an interference screw fixation are significantly closer to those in the intact knee than with extracortical fixation with two staples. MATERIALS AND METHODS: Using a robotic/universal force moment sensor (UFS) testing system, we examined joint kinematics and in situ forces of porcine knees following single-bundle PCL reconstruction fixed at two different tibial fixation sites: anatomical interference screw and extracortical fixation. RESULTS: The site of the tibial graft fixation had significant effect on the resulting posterior displacement and in situ forces of the graft. Both PCL reconstruction techniques reduced the posterior tibial translation significantly. Proximal fixation techniques provided significantly less posterior tibial translation than extracortical fixation. Single-bundle PCL reconstruction with an interference screw showed higher in situ forces of the graft than the extracortical fixation. CONCLUSIONS: The kinematics and in situ forces of a single-bundle PCL reconstruction using an interference screw fixation technique are superior to the primary stability of an extracortical fixation with staples.

Animals↗

PubMed2004

Biomechanical evaluation of a new cross-pin technique for the fixation of different sized bone-patellar tendon-bone grafts.

To overcome the disadvantages of interference-screw fixation of bone-patellar tendon-bone (BPTB) grafts, new fixation techniques for anterior cruciate ligament (ACL) grafts using biodegradable pins have been developed. The hypothesis of the present study was that cross-pin fixation techniques provide a primary stability that is comparable to that of interference screws. A biomechanical in vitro study was discussed. Human BPTB grafts of 8, 9 and 10 mm diameter were fixed in bovine knees with biodegradable cross pins (diameter: 2.0, 2.7 or 3.2 mm) or biodegradable interference screws. Stiffness and ultimate load were evaluated. For 9 and 10 mm BPTB grafts, no statistically significant difference in maximum load and stiffness was found between the four fixation techniques tested. For 8 mm bone blocks the maximum load of the 3.2 mm pins (274.2 N) was significantly lower than for the 2.0 mm pins (479.8 N) and the interference screws (504.0 N). Predominant failure mode in this group was bone-block fracture. Thicker grafts (9 and 10 mm) fixed with the 2.0 mm pins predominantly failed by implant fracture. Femoral fixation of 8, 9 and 10 mm BPTB grafts using cross pins leads to biomechanical properties that are comparable to biodegradable interference screws when tested by a single-cycle load to failure. Cross pins provide a rigid fixation for 9 and 10 mm BPTB grafts.

Absorbable Implants↗

PubMed2004

Vascular endothelial growth factor (VEGF) induces matrix metalloproteinase expression in immortalized chondrocytes.

VEGF (vascular endothelial growth factor), an important angiogenesis factor, appears also to be involved in inflammatory processes. Recent studies have shown that VEGF and its receptors (VEGFR) are expressed on osteoarthritic, but not on normal adult, chondrocytes. To elucidate possible functions of VEGF in osteoarthritic cartilage, the effects of VEGF were studied on immortalized human chondrocytes. Activated matrix metalloproteinase (MMP)-1, MMP-3, MMP-13, tissue inhibitor of metalloproteinases (TIMP)-1, TIMP-2, interleukin (IL)-1beta, IL-6, and tumour necrosis factor-alpha (TNF-alpha) were measured in culture supernatants by enzyme-linked immunosorbent assays, nitric oxide with the Griess reagent, and cell proliferation by [3H]thymidine incorporation. VEGFR-2 mRNA was quantified by real-time reverse transcription-polymerase chain reaction and the protein was identified by immuno-gold electron microscopy. Intracellular signal transduction effects were determined by western blots and electrophoretic mobility shift assays. The chondrocyte cell lines C28/I2, C20/A4, and T/C28a2/a4 expressed functionally active VEGFR-2. VEGF stimulation induced receptor phosphorylation, activation of the mitogen-activated protein kinases ERK 1/2, and long-lasting activation of the transcription factor AP-1 (activator protein-1). VEGF increased secreted MMP-1, MMP-3, and especially MMP-13, which could be effectively reduced by an inhibitor of VEGFR-2 kinase activity. Interestingly, VEGF diminished the expression of TIMP-1 and especially TIMP-2. Under hypoxic conditions, as occur in cartilage, the reduction in TIMP levels was even greater. Furthermore, VEGF induced IL-1beta, IL-6, TNF-alpha, and nitric oxide expression to a small extent and stimulated the proliferation of immortalized chondrocytes. These findings indicate that VEGF is an autocrine stimulator of immortalized chondrocytes that mediates mainly destructive processes in osteoarthritis.

Autocrine Communication↗

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

Mechanical overload induces VEGF in cartilage discs via hypoxia-inducible factor.

VEGF (vascular endothelial growth factor) is not only one of the most important angiogenesis factors, but is involved also in inflammatory processes. Recent studies have shown that VEGF as well as its receptor VEGFR-2 are expressed on osteoarthritic chondrocytes, but not on normal adult chondrocytes. Since mechanical overload is one of the causative factors for osteoarthritis, we studied its effect on VEGF expression on bovine cartilage disks that were compressed once with a strain of 50% and a strain rate of 1/second. Under these conditions, control disks (without pressure) were completely negative for VEGF expression as evidenced by immunocytochemical stainings as well as by enzyme-linked immunosorbent assay (ELISA) measurements. In contrast, 4 days after mechanical overload, the cartilage disks were positive in both detection methods. In addition, after mechanical overload chondrocytes were strongly immunopositive for hypoxia-inducible factor-1alpha (HIF-1alpha), the limiting protein of the dimeric transcription factor HIF-1 that is known to induce VEGF expression. Furthermore, the matrix metalloproteases MMP-1, MMP-3, and MMP-13, could be easily detected in pressure-treated disks by immunohistochemistry whereas staining in controls was low or undetectable. The tissue inhibitors of metalloproteinases (TIMP-1 and -2) could be detected in controls but not in samples treated with mechanical overload. To prove that increased MMP or decreased TIMP expression could be a result of the autocrine action of VEGF on chondrocytes, we repeated the experiments in the presence of a specific inhibitor for the kinase activity of the VEGFR-2. This inhibitor was effective to reduce mechanically induced MMP-1, -3, and -13 immunostaining and to restore TIMP expression. Taking together, these findings indicate that VEGF is induced in chondrocytes by mechanical overload and mediates destructive processes in osteoarthritis as an autocrine factor.

Animals↗

PubMed2004

Expression of VEGFR-1 and VEGFR-2 in degenerative Achilles tendons.

Evidence suggests neovascularization is involved in the etiology of spontaneous Achilles tendon rupture. Therefore we investigated expression of the receptors of one of the most important angiogenic factors, the vascular endothelial growth factor in normal and pathologic human Achilles tendons by immunohistochemical and molecular biology methods. Light microscopy showed degenerative changes in all spontaneously ruptured tendons with a higher vascular density compared with controls of healthy tendons from a cadaver. The vascular endothelial growth factor receptors-1 and 2 could be immunostained in endothelial cells of ruptured and fetal tendons, but not in normal tendons. Reverse transcription-polymerase chain reaction showed messenger ribonucleic acid of both receptors are expressed in ruptured and fetal tendons but not in normal tendons. These results prove the reexpression of the major receptors for the angiogenic peptide vascular endothelial growth factor, the vascular endothelial growth factor receptor-1, and the vascular endothelial growth factor receptor-2 in ruptured and fetal tendons and support our theory that high vascular density is associated with the pathogenesis of tendon degenerations. Inhibiting angiogenesis could be a new approach in the therapy of degenerative Achilles tendon disease.

Achilles Tendon↗

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

A prospective study of kitesurfing injuries.

BACKGROUND: To date, the pattern and rate of kitesurfing injuries are largely unclear. HYPOTHESIS: The pattern and rate of kitesurfing injuries are comparable to that of contact sports such as football and soccer. STUDY DESIGN: Prospective study. METHODS: The study was conducted over a 6-month period of 1 season and included 235 kitesurfers. RESULTS: The number of self-reported injuries was 124, for an overall self-reported injury rate of 7 per 1000 hours of practice. One fatal accident (polytrauma) and 11 severe injuries occurred during the study period (2 knee ligament injuries and 9 fractures at various sites). The most commonly injured sites were the foot and ankle (28%), skull (14%), chest (13%), and knee (13%). Fifty-six percent of the injuries were attributed to the inability to detach the kite from the harness in a situation involving loss of control over the kite. There was a tendency for athletes using a quick-release system to sustain fewer injuries than athletes without such a release system. CONCLUSION: Kitesurfing can be considered a high-risk sport. CLINICAL RELEVANCE: The use of a quick-release system that enables the surfers to detach the kite in case of an accident might aid in the prevention of injuries.

Adolescent↗

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↗