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Biomedical subjects

W Petersen

Publications and source records attributed to W Petersen.

At least 19 recordsLinked to original sources
PubMed2006

4q35 deletion and 10p15 duplication associated with immunodeficiency.

We report a familial cryptic reciprocal translocation between 4q35 and 10p15 leading to deletion of the terminal long arm of chromosome 4 and duplication of the terminal short arm of chromosome 10 in two family members who both have immunological disturbances and a similar facial appearance. The precise location and extent of the deletion and duplication was determined by fluorescence in situ hybridization (FISH). Furthermore, we investigated the deletion breakpoint of a previously reported patient with 4q34.3-qter deletion [Van Buggenhout et al. (2004); Am J Med Genet Part A 131A:186-189].

Abnormalities, Multiple↗
PubMed2006

Effects of menstrual-cycle hormone fluctuations on musculotendinous stiffness and knee joint laxity.

The high risk of anterior cruciate ligament (ACL) injuries in female athletes may be related to hormonal fluctuations resulting in an increased laxity of ligaments and muscles. This study examined changes in lower limb musculotendinous stiffness (MTS) and knee laxity over the course of the menstrual cycle and investigated the interaction of warm-up on MTS. Eleven female netball players aged 16-18 years who were not using hormonal contraceptives and demonstrated regular menstrual cycles participated in this study. Test-sessions were conducted at onset of menses, mid-follicular phase, ovulation and mid-luteal phase. ACL laxity was determined at each test-session using a KT2000 knee arthrometer. MTS was assessed prior to, and following a standardised warm-up. Repeated measures ANOVA revealed significant (P < 0.05) main effects of test-session and warm-up on MTS. MTS was found to significantly decrease by 4.2% following the warm-up intervention. MTS was significantly lower at week 3 (ovulatory phase) in contrast to weeks 1 and 2 (8.7 and 4.5%, respectively). For knee laxity measures, repeated measures ANOVA revealed no significant (P < 0.05) differences across the menstrual cycle. A reduction in MTS results in greater reliance on reflexive response from the contractile components of the muscle due to a decreased contribution from passive elastic structures and will also increase electromechanical delay. Given that extreme loads are applied to the knee joint within milliseconds, the contractile components cannot respond quickly enough to counteract these sudden and potentially damaging forces. These effects are augmented following a moderate warm-up. Oestrogen fluctuations had no significant effect on anterior knee laxity, however, the effects on MTS over the 28-day cycle were considerable. Future studies should use matched subjects who are using the monophasic oral contraceptive pill to investigate the effects of oestrogen supplementation on lower limb MTS.

Adolescent↗
PubMed2006

[Fracture of the tibial head].

Fractures of the tibial head are severe injuries, characterized by enormous variety. Fractures can be classified into fractures of the tibial plateau, luxation fractures, and comminuted fractures. Due to the mechanism of injury luxation fractures are frequently associated with lesions of the menisci and intra- and extra-articular ligaments. Multiple factors can be etiologic for post-traumatic gonarthrosis: nonanatomic reduction of the joint surface, malalignment, and unaddressed associated injuries. Therefore in addition to diagnostic steps such as X-ray, CT scan, and MRI a sophisticated therapeutic regime is necessary. In cases with severely damaged soft tissue or unstable patients, the fracture should initially be reduced and fixed with an external fixator and the definite fixation should be performed in a second setting. Arthroscopically assisted treatment is reserved for fractures of the tibial eminence, crack fractures, and impression fractures. Comminuted and bilateral fractures can be addressed via different incisions. New locking plates with angular stability allow avoidance of bilateral plating in most situations. In specific cases such as compound fractures and for patients with low compliance, a hybrid fixator may be a well-chosen alternative.

Arthroscopy↗
PubMed2006

[Avulsion injury to the posterior horn of the lateral meniscus. Technique for arthroscopic refixation].

An avulsion of the posterior tibial insertion of the meniscus (root tear) is a rare clinical diagnosis. Yet, due to the inconsistent clinical symptoms and the difficult arthroscopic assessment, an injury to the root of the meniscus can be easily missed. We present a possible technique for arthroscopic management of root tears using a tibial tunnel approach. A possible injury mechanism could be a rotational distortion of the knee. Another mechanism of injury is an overly posterior tunnel placement in ACL reconstruction. The clinical assessment of the lesion is based on thorough arthroscopic diagnosis of the lateral posterior horn in the figure of 4 position. A tibial ACL aimer can be used to locate a K-wire in the anatomical footprint of the posterior root of the meniscus. After overdrilling using a 4.5-mm drill, two sutures can be passed through the meniscal tissue and the sutures can be pulled out of the tibial tunnel. Extracortical fixation can be used by tying the sutures over a button.A root tear of the meniscus is a difficult clinical and arthroscopic diagnosis. A possibility for refixation of this lesion is to use a tibial tunnel technique. An associated injury to the ACL facilitates the tunnel placement and the suture management.

Anterior Cruciate Ligament↗
PubMed2005

[Rupture of the quadriceps tendon. Diagnosis and treatment of a rare injury].

Rupture of the quadriceps tendon is a rare knee injury. In most cases the tendon ruptures spontaneously without adequate trauma in patients older than 40 years with degenerative changes of the tendon. Suture repair is the only treatment option for acute complete, older ruptures and partial ruptures that do not heal after nonoperative treatment. The type of repair depends on the time of diagnosis and localisation of the rupture. The functional outcome depends on timely repair and early initiation of knee movement and strengthening therapy.

Humans↗
PubMed2005

[Kitesurfing injuries. A trendy youth sport ].

The aim of this review article is to give an overview of current knowledge on kitesurfing injuries. As part of a prospective study, the overall self-reported injury rate was 7.0 per 1000 h of practice. One fatal accident and 11 severe injuries occurred. The most commonly injured sites were foot and ankle, head, chest, and knee. Contusions, abrasions, and lacerations were amongst the most frequent injuries. None of the athletes suffering a head injury used a helmet; the board had been flung against the head by the elastic board leech in all cases. The most common injury situation was the jump. Fifty-six percent of the injuries were attributed to the inability to detach the kite from the harness. There was a tendency that athletes using a quick release system, which enables the surfers to detach the kite in emergency situations, sustained fewer injuries than athletes without such a release system. In conclusion, kitesurfing is a sport with a comparably high injury rate. Preventive measures can reduce the injury rate considerably.

Athletic Injuries↗
PubMed2005

[Overload damage to the Achilles tendon: the importance of vascularization and angiogenesis].

In the Achilles tendon, degenerative changes mostly occur in regions that are hypo- or avascular. Angiogenesis is mediated by angiogenic factors and recent studies have shown that vascular endothelial growth factor (VEGF) is highly expressed in degenerative Achilles tendons, whereas VEGF expression is nearly completely downregulated in healthy tendons. VEGF expression in tendon fibroblasts is regulated by the transcription factor hypoxia inducible factor 1 (HIF-1). Several factors are able to upregulate VEGF expression in tenocytes: hypoxia, inflammatory cytokines and mechanical load. Angiogenesis plays an important role in the tendinotic process. The neovessels are accompanied by small glutamate positive neural structures. This finding suggests that angiogenesis plays an important role in the pain experienced during the degenerative tendon disease. On the other hand, there is some evidence that HIF-1/VEGF induced angiogenesis has an effect on the material properties of the tendinotic tendon tissue. Since VEGF has the potential to stimulate the expression of matrix metalloproteinases and inhibits the expression of tissue inhibitors of matrix metalloproteinases (TIMP) in various cell types this cytokine might play a significant role in the pathogenetic processes during degenerative tendon disease. These experimental findings are in accordance with clinical results which show that eccentric training leads to a regression of neovessels and decrease of pain. Another strategy is the local administration of a sclerosing agent (Polidocanol) to destroy neovessles. Preliminary results show that both strategies are effective in reducing vascular density and pain.

Achilles Tendon↗
PubMed2004

["Shrinkage of cruciate ligaments"--a biomechanical study. Shrinkage of elongated cruciate ligaments using an application of radiofrequency energy].

The aim of this study was to evaluate structural properties of native and elongated bovine anterior cruciate ligaments after the application of bipolar radiofrequency. Using a material testing machine typical load-elongation curves were used to determine the initial strength of untreated (group 1, n = 20) and elongated cruciate ligaments (group 2, n = 20) after treatment with bipolar radiofrequency (ArthroCare). After the application of a cyclic loading protocol (1000 x 400 N) elongation, yield load, maximal load, and stiffness were determined. Native ligaments served as a control group (group 3, n = 20). In both groups 4 mm reduction in length was caused by the application of radiofrequency. Elongation was significantly higher; yield load, maximal load, and stiffness of cruciate ligaments treated with radiofrequency (groups 1 and 2) were significantly reduced after the application of a cyclic loading protocol in comparison to the control group (p < 0.05). Group 2 ligaments showed the lowest values. The application of radiofrequency weakens the biomechanical properties of native and elongated cruciate ligaments significantly. When radiofrequency energy is used to shrink elongated cruciate ligaments, a nonaggressive rehabilitation protocol should be applied.

Animals↗
PubMed2004

[Injuries in Olympic handball tournaments: a video analysis].

INTRODUCTION: The aim of the study was to achieve injury situations in European team handball with a video based method. METHODS: A video tape containing 59 injuries of an Olympic handball tournament were analyzed by two observers (sports-scientist, orthopaedic surgeon). The analysis was based on a method previously published by Teitz, which was developed to analyze ACL-injuries. The parameters body region, field position, contact/non-contact, offense/defense, field player/goal keeper were mainly used. RESULTS: The most injuries were localized at the head (N = 20), the lower limb (N = 15), thorax and abdomen (N = 9) and the upper limb (N = 9). Concerning the field, the most injuries were in the midfield (N = 20), followed by the left (N = 13) and right (N = 9) outside position. The injured players were mostly in the offense (84 %), and in the majority of cases the field players were affected (97 %). 86 % of the injuries accomplished by contact. CONCLUSION: The head has a high risk, predominantly of contact injury. Contact-injuries could only be reduced by strict decisions of the referees. Non-contact injuries should be prevented by a special coordinative training.

Arm Injuries↗
PubMed2004

Expression of vascular endothelial growth factor during healing of the meniscus in a rabbit model.

Our aim was to investigate vascular endothelial growth factor (VEGF) expression after lacerations of a meniscus in a rabbit model. Specimens of meniscus were examined using immunohistochemistry, enzyme-linked immunoassay and the reverse transcription polymerase chain reaction after one, two, five or ten weeks. In the periphery of the meniscus 90% of the lacerations had healed after five and ten weeks, but no healing was observed in the avascular area. Expression of VEGF protein and VEGF mRNA was found in the meniscus of both the operated and the contralateral sites but both were absent in control rabbits which had not undergone operation. The highest expression of VEGF was found in the avascular area after one week (p < 0.001). It then lessened at both the vascular and avascular areas, but still remained greater in comparison with the control meniscus (p < 0.05). Despite greater expression of VEGF, angiogenesis failed at the inner portion. These findings demonstrated the poor healing response in the avascular area which may not be caused by an intrinsic cellular insufficiency to stimulate angiogenesis.

Animals↗
PubMed2003

Pleiotrophin, an embryonic differentiation and growth factor, is expressed in osteoarthritis.

OBJECTIVE: Pleiotrophin (PTN) is a 15.3 kDa heparin-binding peptide, which is expressed in mesodermal and neuroectodermal cells during development, but rarely in adult tissues. In fetal or juvenile cartilage, PTN is an abundant protein and appears to be involved in chondrocyte differentiation. Since developmentally regulated factors often re-appear in the disease state, we examined PTN expression in cartilage and synovial fluid of patients with osteoarthritis (OA). METHODS: PTN mRNA and protein expression was assayed by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot, the protein was localized by immunohistochemistry and quantified by enzyme-linked immunoassay (ELISA). RESULTS: PTN was undetectable in normal adult cartilage, but PTN mRNA and protein were found in OA. In cartilage from the tibial plateaus of OA patients, PTN could be immunostained in clusters of superficial chondrocytes. In the synovial fluids of OA patients, PTN concentrations were elevated in earlier OA stages, but rarely in late OA stages. Chondrosarcomas were PTN-immunonegative. CONCLUSIONS: In addition to certain types of cancer, the embryonic growth and differentiation factor PTN is found also in adults in inflammatory diseases. In OA, PTN is especially expressed in early stages, and PTN concentrations in the synovial fluid could serve as a marker for the progress of the disease. PTN might be involved in cartilage repair in OA, in particular, in earlier stages.

Adult↗
PubMed2003

[Biomechanical examinations of the efficacy of wrist guards in inline skating].

INTRODUCTION: Fractures of the wrist and forearm are the most frequent injuries in Inline-Skating. Clinical experience has shown that these injuries can be prevented the use of wrist protectors. But various authors have shown that fractures can also occur despite the use of wrist protectors. Aim of this study was to examine different wrist protectors in a biomechanical set up. METHOD: A standardized trauma was simulated using an artificial hand with a certain weight. The forces with or without protective devices have been recorded by a force moment sensor. The results of different protectors have been compared. RESULTS: A mean force of 956 N was measured without the use of a protective device. With the application of a wrist protector these forces were reduced between 4 and 20 %. The best values have been reached with models with a strong base plate. CONCLUSIONS: The results of the present study may explain the clinical observation that wrist and forearm fractures can occur despite the use of a wrist guard. The protective effect of a wrist protector depends highly on the model that is used.

Athletic Injuries↗
PubMed2003

[Epidemiology of injuries in juvenile handball players].

INTRODUCTION: Aim of the study was to elucidate epidemiological aspects and injury mechanisms in juvenile team handball. METHOD: A standardized questionnaire was used to evaluate the injuries of 100 juvenile players (50 male, 50 female, year of birth 1982/83). RESULTS: A total of 130 injuries were recorded of 73 players. Most of the injuries (73.1%) occurred between the age of 15 and 18. Approximately two thirds of the injuries (69.2%) occurred in a competition and most of them in an offensive situation. Backcourt players (29.0%), line players (27.5%), and goalkeepers (17.0%.) were the player positions to be most injured. Female goalkeepers were three times more often injured than male ones at the same age. Most injuries applied to the foot and the ankle (32.0%), followed by the finger joint (26.9%) and the knee (24.6%). The most frequent ankle injuries were ruptures of the lateral ankle ligaments. The knee joint was affected by the most severe injuries with the need of surgical therapy. The most common injury concerning the knee joint was rupture of the anterior cruciate ligament (ACL). Eleven ACL tears were recorded in the age between 15 and 18 years (12-14 years: 1; 8-12 years: 0). The most typical game situation at the point of injury was catching a ball (38.5%), contact situation with the opponent (34.5%), or landing after a jump (26.2%). CONCLUSIONS: This study allows conclusions concerning prevention of injuries in juvenile team handball. There is apparently a difference in muscle strength and coordination of the youth handball player, especially at the age of 15-18 years, which has to be addressed. Therefore the authors recommend a proprioceptive training program as well as exercises to improve jumping techniques. Special strengthening training for the finger muscles might help to prevent finger injuries. The frequency of contact injuries underlines the importance of a "fair play" campaign among young players.

Adult↗
PubMed2003

[Mechanisms and prevention of windsurfing injuries].

Aim of this study was to analyse the mechanisms of windsurfing injuries. For this purpose we performed a internet based survey among 327 windsurfers in Germany. Overall 630 accidents have been registered among all 327 athletes during the 2000 season. The majority of injuries were classified as minor injury. The most common injury was the bruise. 70 participants reported fractures, 26 participants ruptured a ligament. 280 injuries required medical treatment; in 67 cases even surgical treatment was necessary. The majority of accidents happened at wind power of 5-6 Beaufort after 2 hour exercise. A technical mistake was the most frequent cause for the accident. The most dangerous manoeuvres were difficult jumps (e. g. front loop, backward loop, 70 injuries). In 46 cases the weather conditions were underestimated. Only 10 windsurfers reported about broken material as cause for the injury. One half of the injuries happened in wave conditions. The analysis of injury mechanisms allows conclusions regarding injury prevention. A longer break after 60 minutes windsurfing might help to prevent injuries due to poor physical fitness. After one hour windsurfing without a break training of difficult manoeuvres should not be performed. The use of a helmet might prevent head injuries during training of difficult jumps. "Overpower situations" should be prevented by choosing the right board and sail size.

Adult↗
PubMed2003

Survival analysis of hips treated with flexion osteotomy for femoral head necrosis.

The treatment of osteonecrosis of the femoral head (FHN) is controversial. It mainly occurs in young patients in whom total hip replacement is best avoided because of an increased risk of revision. The objective of this long-term follow-up study was to evaluate the outcome of intertrochanteric flexion osteotomy as a hip joint preserving operation for FHN. Over a 19-year period we carried out 70 intertrochanteric flexion osteotomies for FHN in 64 patients. The mean follow-up was 10.4 years (3.0 to 20.3). The overall mean Harris hip score increased from 51 points preoperatively to 71 points postoperatively. Six patients (9%) developed early postoperative complications. A total of 19 hips (27%) underwent total hip arthroplasty at a mean of 8.7 years after osteotomy. The five-year survival rate was 90%. Survival rates of hips in Ficat stage 2 were higher than those in stages 3 or 4. Hips with a preoperative necrotic angle of <200 degrees had a better survival probability than those with a necrotic angle >200 degrees. Our findings suggest that flexion osteotomy is a safe and effective procedure in Ficat stage 2 and 3 FHN, preferably with a necrotic angle of <200 degrees.

Adolescent↗
PubMed2002

[Anatomy and function of the anterior cruciate ligament].

The anterior cruciate ligament originates at the medial wall of the lateral femoral condyle and inserts into the middle of the intercondylar area. It contributes significantly to the stabilization and kinematics of the knee joint. The femoral origin is oval and is located in the posterior aspect of the lateral femoral condyle. Therefore, it is difficult to visualize the femoral origin arthroscopically. This might be one reason for anterior malpositioning of the femoral bone tunnel during anterior cruciate ligament reconstruction. The position of the femoral origin is behind the center of rotation of the knee joint; therefore, it becomes tense when the knee is extended. The tibial insertion is oval and its center is nearly in the middle of the tibial plateau. Definite landmarks for tibial tunnel placement in anterior cruciate ligament reconstruction are the distance between the central insertion point at the intercondylar floor and the posterior cruciate ligament (7-8 mm) and the anterior horn of the lateral meniscus. The anterior cruciate ligament consists of multiple small fiber bundles. From a functional point of view, one can differentiate the anteromedial and posterolateral fiber bundles. The anteromedial fibers are tense during a greater range of motion than the posterolateral fibers. The main part of the anterior cruciate ligament consists of type I collagen-positive dense connective tissue. The longitudinal fibrils of type I collagen are divided into small bundles by thin type III collagen-positive fibrils. In the distal third, the structure of the tissue varies from the typical structure of a ligament. In this region, the structure of the tissue resembles fibrocartilage. Oval-shaped cells surrounded by a metachromatic extracellular matrix lie between the longitudinal collagen fibrils. The femoral origin and the tibial insertion have the structure of a chondral apophyseal enthesis. Near the anchoring region at the femur and tibia, there should be various mechanoreceptors, which might have an important function for the kinematics of the knee joint. The blood supply of the anterior cruciate ligament arises from the middle geniculate artery. The ligament is covered by a synovial fold where the terminal branches of the middle and the inferior geniculate artery form a periligamentous network. From the synovial sheath, the blood vessels penetrate the ligament in a horizontal direction and anastomose with a longitudinally orientated intraligamentous network. The distribution of blood vessels within the anterior cruciate ligament is not homogeneous. We detected three avascular areas within the ligament: Both fibrocartilaginous entheses of the anterior cruciate ligament are devoid of blood vessels. A third avascular zone is located in the distal zone of fibrocartilage adjacent to the roof of the intercondylar fossa.

Anterior Cruciate Ligament↗