[Assessments in medical training : What makes assessments interesting?] / Gutachten in der Weiterbildung : Was macht Gutachten interessant?

The assessment represents an elementary medical task. The medical assessment is the basis of a legal decision and is initiated by the client if medical expertise is required to assess a situation. A medical assessment is a scientifically based conclusion made by a physician about a person's state of health or functional limitations or other medical circumstances. The reports must be scientifically sound, medically conclusive, understandable and comprehensible. The ability to do this is acquired as part of medical further training after obtaining a license to practice medicine. With a systematic approach to the preparation of reports, one's own treatment processes can be improved and lessons can be learnt from mistakes. Expert opinions in the context of further training are of enormous importance for further professional life.

[Salter-Harris type IV epipyseal fracture of the lateral malleolus. A rare injury in childhood]. / Salter-Harris-Typ-IV-Epiphysenfraktur am Außenknöchel. Eine seltene Verletzung im Kindesalter.

This is a case presentation of a 9-year-old boy who sustained a rare Salter-Harris type IV distal fibular fracture including an avulsion fracture of the anterior inferior tibiofibular ligament at the fibular attachment. Treatment consisted of open reduction and internal fixation by Kirschner wire and cerclage. Possible posttraumatic growth disturbances and the major implications are highlighted.

[Clinically symptom-poor isolated rupture of the biceps tendon of the knee close to the attachment. Can an operative approach always be recommended?]. / Die klinisch symptomarme isolierte ansatznahe Ruptur der Bizepssehne am Kniegelenk. Ist ein operatives Vorgehen uneingeschränkt empfehlenswert?

Isolated avulsions involving the tendon of the biceps femoris muscle are rare injuries. Injury patterns are similar to those of posterolateral knee injuries mostly due to hyperextension and external rotation. Functional loss is common regarding painful limited flexion of the knee. In the case described in this article there was complete avulsion of the biceps femoris tendon but low levels of pain and functional loss despite the proximity to the attachment.

[Total hip arthroplasty with the cementless spiron femoral neck prosthesis]. / Hüftgelenkersatz mit der zementfreien Spiron-Schenkelhalsprothese.

OBJECTIVE: Cementless total hip arthroplasty with preservation of femoral neck and natural load transmission. Restoration of joint function and alleviation of pain. INDICATIONS: Osteoarthritis of the hip or femoral head necrosis in younger patients. CONTRAINDICATIONS: Patients biologically > 65 years. Destructed or discontinued femoral neck. Pathologic hip formation: short femoral neck, severe enhanced or reduced CCD angle. Body mass index (BMI) > 30 (relative contraindication). Manifest osteoporosis. Necessity of immediate full weight bearing. Heavy smoking (relative contraindication). Ongoing chemotherapy. SURGICAL TECHNIQUE: Anterolateral approach to the hip joint. Exposition of the femoral neck and resection of the femoral head at its lateral margin. Preparation of the acetabulum and insertion of a common acetabular component. Positioning of the center pin into the femoral neck. Face milling of the femoral neck butt. Preparation of the femoral neck with the Spiron drill bit. Insertion of the Spiron prosthesis. Trial reduction with a trial head. Substitution by the definitive head (cone 12/14 mm). Wound closure. POSTOPERATIVE MANAGEMENT: Low centred X-ray of the pelvis and cross table view of the hip joint. Physiotherapy and partial weight bearing for 6 weeks. Prevention of deep vein thrombosis until achievement of full weight bearing. RESULTS: A total of 28 Spiron prosthesis were implanted in 26 patients (15 men, 11 women, mean age 51 years [range 34-64 years], mean BMI 28 kg/m(2) [range 21-39 kg/m(2)]) from August 2009 to January 2012. Diagnoses: 13 cases of primary osteoarthritis, 8 cases of secondary osteoarthritis, 5 cases of femoral head necrosis, and 2 cases of posttraumatic osteoarthritis. The mean surgery length was 93 min (range 70-121 min), the mean hospital stay was 9 days (range 6-16 days). Blood transfusion was not necessary in any of the cases. There were no immediate complications such as deep vein thrombosis, surgery requiring secondary bleeding, wound infection, nerve palsy, or dislocation of the hip. Postoperative radiologic examinations showed an average leg lengthening of 3 mm (range -10-19 mm). No varus deviation of the prosthesis was observed. The Harris Hip Score improved from 55.4 points (range 33.5-76.9 points) preoperative to 90.5 points (range 75.7-99.9 points) 3 months postoperative. In 1 case with aseptic loosening, replacement surgery was performed without complications.

Influence of rupture patterns of the medial patellofemoral ligament (MPFL) on the outcome after operative treatment of traumatic patellar dislocation.

PURPOSE: Patellar dislocation usually occurs to the lateral side, leading to ruptures of the medial patellofemoral ligament (MPFL) in about 90 % of all cases. Reliable prognostic factors for the stability of the patellofemoral joint after MPFL surgery and satisfaction of the patient have not been established as yet. METHODS: This multicentric study retrospectively included 40 patients with a mean age of 22.4 ± 8.1 years (range 9-48) from 5 German Trauma Departments with first-time traumatic patellar dislocation and operative treatment. Surgery was limited to soft tissue repairs, and a preoperative magnetic resonance imaging (MRI) was performed in all cases. Evaluation of the MRI included sulcus angle, dysplasia of the trochlea, depth and facet asymmetry of the trochlea, Insall-Salvati index, Tibial tuberosity to trochlear groove (TTTG) distance, and rupture patterns of the MPFL. Patients were interrogated after 2 years about recurrent dislocation, satisfaction, and the Kujala score. RESULTS: Trochlea facet asymmetry was significantly lower in patients with redislocation (23.5 ± 18.8) than in patients without redislocation (43.1 ± 16.5, p = 0.03). Patients with a patellar-based rupture were significantly younger (19.5 ± 7.2 years) than patients without patellar-based rupture (25.4 ± 8.1 years, p < 0.02). Patients with femoral-based ruptures were significantly older (25.7 ± 9.2 years) than patients without femoral-based rupture (19.7 ± 6.1 years, p < 0.02), and had a significantly higher TTTG distance (10.2 ± 6.9 vs. 4.5 ± 5.5, p < 0.02). Patients with incomplete ruptures of the MPFL had a significantly lower Insall-Salvati index (1.2 ± 0.2 vs. 1.4 ± 0.2, p = 0.05). The Kujala score in patients with redislocations was significantly lower (81.0 ± 10.5 points) than in patients without redislocation (91.9 ± 9.2 points, p < 0.02). CONCLUSION: Younger patients more often sustain patellar-based ruptures following first-time traumatic patella dislocation, while older patients more often sustain femoral-based ruptures of the MPFL. Incomplete MPFL ruptures are correlated with lower Insall-Salvati indices. Low trochlear facet asymmetry is correlated with higher rates of redislocation. These results may be of relevance for the operative and postoperative treatment in the future. LEVEL OF EVIDENCE: Prognostic study, Level IV.

Operative vs conservative treatment of traumatic patellar dislocation: results of a prospective randomized controlled clinical trial.

INTRODUCTION: Patellar dislocation is a common knee injury with mainly lateral dislocations, leading to ruptures of the medial patellofemoral ligament in most of the cases. Even though several prognostic factors for patellofemoral instability have been identified so far, the appropriate therapy for patients with patellar dislocation remains a controversial issue. The purpose of this study was to compare the outcome after conservative or operative treatment in patients after first-time patellar dislocation. PATIENTS AND METHODS: This randomized controlled clinical trial was designed multicentric including patients from six German orthopaedic and trauma departments. Twenty patients with a mean age of 24.6 years with first-time traumatic patella dislocation were included and randomized into either a conservative arm or an operative arm. Plain X-ray images of the knee joint (a.p. and lateral view and tangential view of both patellae) were performed in all cases prior to therapy to exclude osteochondral fragments requiring refixation. An MRI was recommended, but not compulsory. Patients were consulted after 6, 12, and 24 months with a questionnaire including the criteria of the Kujala score, recurrent dislocation, and satisfaction. RESULTS: The mean Kujala score of the conservative vs operative treatment group was 78.6 vs 80.3 after 6 months (p = 0.842), 79.9 vs 88.9 after 12 months (p = 0.165), and 81.3 vs 87.5 after 24 months (p = 0.339). Redislocation rate after 24 months was 37.5 % in the conservative group and 16.7 % in the operative group (p = 0.347). Due to the small number of patients that could be included, no significant difference between the groups could be detected. We see a tendency towards better results after operative treatment. CONCLUSION: Our multicentric prospective randomized controlled trial revealed no significant difference between conservative and operative treatment for patients after first-time traumatic patellar dislocation. However, a tendency towards a better Kujala score and lower redislocation rates for patients with operative treatment was observed. The small number of patients is a limiting factor of the study, leading to results without statistical significance. A meta-analysis including other study's level I data is desirable for the future.

[Rehabilitation management system of the German Social Accident Insurance. Initial medical experiences]. / Reha-Management in der gesetzlichen Unfallversicherung. Erste durchgangsärztliche Erfahrungen.

To improve outcome quality of rehabilitation, the German Social Accident Insurance implemented a rehabilitation management system. A rehabilitation manager operates as active supervisor of the rehabilitation process of severely injured persons beginning from the time when the accident happened. The sequence is recorded on a rehabilitation schedule by the physician, rehabilitation manager and patient together. The concept has not yet been fully accepted by all insurers. Furthermore there is no uniform approach in compiling the rehabilitation schedule which can lead to delays in the process and insecurity of patients. In the following article these aspects are illustrated and improvement suggestions are highlighted.

[Acute lower leg compartment syndrome]. / Das akute Kompartmentsyndrom des Unterschenkels.

OBJECTIVE: Decompression of all four muscle compartments of the lower leg to normalize tissue pressure and prevent permanent neuromuscular dysfunction. INDICATIONS: Incipient compartment syndrome (characterized by excessive pain, muscle pain on extension, tensely swollen and shiny skin, and Δp>30 mmHg without neuromuscular deficit) and no clinical improvement after conservative treatment and/or acute compartment syndrome (symptoms as for incipient compartment syndrome with neuromuscular deficit and Δp<30 mmHg). CONTRAINDICATIONS: None. There is some dispute about indications and timing of fasciotomy and necrectomy when the need for dermatofasciotomy is recognized late (e.g. intubated intensive care patients). SURGICAL TECHNIQUE: In unilateral compartment release as described by Matsen, the lateral compartment is decompressed first through a parafibular approach. After identification of the anterior and superficial posterior compartments by transverse incision of the fasciae, these muscles are also decompressed longitudinally. Finally, the deep posterior compartment beneath the lateral compartment is decompressed. In bilateral dermatofasciotomy, the fasciae of the anterior and lateral compartments are incised through a proximal anterolateral approach and the superficial and deep posterior compartments through a distal dorsomedial approach. POSTOPERATIVE MANAGEMENT: Synthetic skin substitute or vacuum-assisted wound closure until definitive closure by secondary suture or mesh grafting after about 5 days. Patient mobilization generally depends on the concomitant bone injury. RESULTS: During the period from October 2001 to November 2008, 37 dermatofasciotomies were performed at our hospital to treat acute posttraumatic compartment syndrome. On the day of dismissal, symptoms of neuromuscular dysfunction after acute compartment syndrome had not disappeared completely in 5 patients. One patient received intermittent dialysis for acute kidney failure after crush syndrome. There were perioperative complications in a total of 6 patients: iatrogenic neurotomy (n=1), hematoma requiring revision (n=2), deep wound infection (n=2), and superficial disturbed wound healing (n=1).

Long-term outcome after joint reconstruction or medial resection arthroplasty for anterior SCJ instability.

INTRODUCTION: In the present study, the long-term results of 11 patients with anterior sternoclavicular joint (SCJ) instability are reported. All included patients had an anterior SCJ instability and due to delayed diagnosis, operative treatment was not done immediately. METHOD: The patients had a mean age of 29.2 years (range 16-63 years). One patient sustained concomitant injuries. Six patients had resection arthroplasty. Five patients had reconstruction of the SCJ with transosseous tension band PDS fixation or ligament reconstruction with additional wire cerclage. The results of treatment were evaluated after a mean follow-up period of 9.9 years (range 1-27 years) using the ASES, DASH and power-, age and gender adjusted Constant-Murley Score. RESULTS: In general, the mean values of the different scores (ASES 79.8; DASH 11.8; Constant-Murley 81%) demonstrated good outcome. The outcome evaluation of the patients who had SCJ reconstruction did not differ significantly from the patients who had medial resection arthroplasty. The rate of postoperative pain or instability was low using visual analog scale and did not differ significantly between the groups. The outcome results of the reconstruction group were equal to the results of the resection group when SCJ-reconstruction was performed soon after SCJ injury. One patient in the resection group (6 patients) demonstrated poor results due to continued instability of the remaining clavicle. CONCLUSION: We concluded that patient selection and a specific clinical indication for operative treatment are crucial. Resection of the medial clavicle results in good functional outcome when the costoclavicular ligament is preserved or reconstructed.

Bone formation in trabecular bone cell seeded scaffolds used for reconstruction of the rat mandible.

This study tested whether different in vitro cultivation techniques for tissue-engineered scaffolds seeded with human trabecular bone cells affect in vivo bone formation when implanted into critical-size defects in rat mandibles. Human trabecular cells were isolated and seeded into three types of scaffolds (porous CaCO(3), mineralized collagen, porous tricalcium phosphate). Four in vitro groups were produced: empty control scaffolds incubated with cell culture medium for 24 h; scaffolds seeded with trabecular bone cells, cultivated under static conditions for 24 h; scaffolds seeded with trabecular bone cells, cultivated for 14 days under static conditions; scaffolds seeded with trabecular bone cells, cultivated for 14 days in a continuous flow perfusion bioreactor. The scaffolds were implanted press fit into non-healing defects, 5 mm diameter, in rat mandibles. After 6 weeks the presence of human cells was assessed; none were detected. Histomorphometric evaluation showed that neither seeding human trabecular bone cells nor the culturing technique increased the amount of early bone formation compared with the level provided by osteoconductive bone ingrowth from the defect edges. It is concluded that human bone marrow stroma cells in tissue-engineered scaffolds and associated in vitro technology are difficult to test in the mandible in animal models.

Effect of seeding technique and scaffold material on bone formation in tissue-engineered constructs.

The aim of the present study was to test the hypothesis that both scaffold material and the type of cell culturing contribute to the results of in vivo osteogenesis in tissue-engineered constructs in an interactive manner. CaCO3 scaffolds and mineralized collagen scaffolds were seeded with human trabecular bone cells at a density of 5 x 10(6) cells/cm(3) and were left to attach under standard conditions for 24 h. Subsequently, they were submitted to static and dynamic culturing for 14 days (groups III and IV, respectively). Dynamic culturing was carried out in a continuous flow perfusion bioreactor. Empty scaffolds and scaffolds that were seeded with cells and kept under standard conditions for 24 h served as controls (groups I and II, respectively). Five scaffolds of each biomaterial and from each group were implanted into the gluteal muscles of rnu rats for 6 weeks. Osteogenesis was assessed quantitatively by histomorphometry and expression of osteocalcin (OC) and vascular endothelial growth factor (VEGF) was determined by immunohistochemistry. CaCO3 scaffolds exhibited 15.8% (SD 3.1) of newly formed bone after static culture and 22.4% (SD 8.2) after dynamic culture. Empty control scaffolds did not show bone formation, and scaffolds after 24 h of standard conditions produced 8.2% of newly formed bone (SD 4.0). Differences between the controls and the scaffolds cultured for 14 days were significant, but there was no significant difference between static and dynamic culturing. Mineralized collagen scaffolds did not show bone formation in any group. There was a significant difference in the expression of OC within the scaffolds submitted to static versus dynamic culturing in the CaCO3 scaffolds. VEGF expression did not show significant differences between static and dynamic culturing in the two biomaterials tested. It is concluded that within the limitations of the study the type of biomaterial had the dominant effect on in vivo bone formation in small tissue-engineered scaffolds. The culture period additionally affected the amount of bone formed, whereas the type of culturing may have had a positive effect on the expression of osteogenic markers but not on the quantity of bone formation.

[Osteogenic differentiation of human bone marrow stromal cells (hBMSC) by cyclic longitudinal mechanical strain and dexamethasone]. / Osteogene Differenzierung von humanen stromalen Zellen aus dem Knochenmark (hBMSC) unter dem Einfluss von zyklischem mechanischem Dehnungsstress und Dexamethason.

AIM: The aim of the study was to investigate the effects of dexamethasone and cyclic mechanical strain on human bone marrow stromal cells (hBMSCs) in osteogenic differentiation by determing levels of mRNA of collagen I, II, III, tenascin C and Cbfa1. METHOD: hBMSCs from seven donors (32.5 +/- 6.2 years old) were cultivated with (D +) or without (D -) dexamethasone. After the second passage 2.2 x 10 (5) cells were seeded on flexible silicon dishes. A cyclic mechanical strain with an elongation of 2 % (D + 2; D - 2) or 8 % (D + 8; D - 8) was applied for three days with a stimulation time of three times for two hours each day. Cells were harvested on day 1, day 1 after stress (day 4) and day 4 after stress (day 7). mRNA expression of collagen I, II, III, tenascin C and Cbfa1 was investigated by RT-PCR. RESULTS: Cbfa1 mRNA levels were significantly different on different days (p < 0.05), and for strain on day 1: 8 %: 0.0291 +/- 0.0338 versus 0 %: 0.00 528 +/- 0.0127, p = 0.017; day 8: 8 %: 0.0411 +/- 0.116, 0 %: 0.00 103 +/- 0.00 217, p = 0.009. All other observed paramaters showed tendencies without significant differences. CONCLUSION: In the short-term over seven days, cyclic stretching is a stronger differentiation factor than dexamethasone.

Influence of perfusion and cyclic compression on proliferation and differentiation of bone marrow stromal cells in 3-dimensional culture.

Until now, there has been no in vitro model that duplicates the environment of bone marrow. The purpose of this study was to analyze proliferation and differentiation of human bone marrow stromal cells (hBMSC) under the influence of continuous perfusion and cyclic mechanical loading. hBMSC of seven individuals were harvested, grown in vitro, and combined. 10(6) hBMSC were seeded on a bovine spongiosa disc and incubated in a bioreactor system. Cell culture was continued using three different conditions: Continuous perfusion (group A), 10% cyclic compression at 0.5Hz (group B) and static controls (group C). After 24h, 1, 2, and 3 weeks, we determined cell proliferation (MTS-assay) and osteogenic differentiation (osteocalcin ELISA, Runx2 mRNA). Tenascin-C mRNA was quantified to exclude fibroblastic differentiation. In groups A and B, proliferation was enhanced after 2 weeks (48.6+/-19.6x10(3) (A) and 44.6+/-14.3 x 10(3) cells (B)) and after 3 weeks (46.6+/-15.1 x 10(3) (A) and 44.8+/-10.2 x 10(3) cells (B)) compared with controls (26.3+/-10.8 x 10(3) (2 weeks) and 17.1+/-6.5 x 10(3) cells (3 weeks), p<0.03). Runx2 mRNA was upregulated in both stimulated groups after 1, 2, and 3 weeks compared to control (group A, 1 week: 5.2+/-0.7-fold; p<0.01, 2 weeks: 4.4+/-1.9-fold; p<0.01, 3 weeks: 3.8+/-1.7-fold; p=0.013; group B, 1 week: 3.6+/-1.1-fold, p<0.01, 2 weeks: 4.2+/-2.2-fold, p<0.01; 3 weeks: 5.3+/-2.7-fold, p<0.01). hBMSC stimulated by cyclic compression expressed the highest amount of osteocalcin at all time points (1 week: 294.5+/-88.4 mg/g protein, 2 weeks: 294.4+/-73.3mg/g protein, 3 weeks: 293.1+/-83.6 mg/g protein, p0.03). The main stimulus for cell proliferation in a 3-dimensional culture of hBMSC is continuous perfusion whereas mechanical stimulation fosters osteogenic commitment of hBMSC. This study thereby contributes to the understanding of physical stimuli that influence hBMSC in a 3-dimensional cell culture system.

[Total knee replacement in a below-knee amputee. Technical reference points and possible solutions]. / Knieendoprothetik beim Unterschenkelamputierten. Technische Besonderheiten der Referenzierung und Lösungsoptionen.

We present the case of a 62-year-old man with posttraumatic osteoarthritis after a tibial head fracture. A below-knee amputation of the same limb had been performed years ago because of a chronic diabetic foot ulcus. The patient underwent total knee replacement, and the 2-year postoperative clinical outcome was very good. The problem of how to address missing anatomic reference points for the implantation of the tibial component in below-knee amputees and the question whether navigation offers a potential benefit in this situation are discussed.

[Localisation of TGF-beta and PDGF and their relevance for the pathogenesis of arthrofibrosis]. / Lokalisation von TGF-beta und PDGF und deren Bedeutung für die Pathogenese der Arthrofibrose.

Arthrofibrosis is a disabling complication after knee trauma and surgery and is characterised clinically by joint stiffness. Due to an immune response, the proliferation of fibroblasts and synthesis of extracellular matrix proteins are increased. The cytokines transforming growth factor beta (TGF-beta) and platelet-derived growth factor (PDGF) are critical players in tissue fibrosis, stimulating cell proliferation and the production of various extracellular matrix proteins. Tissue samples from the infrapatellar fat pad and intercondylar synovia of seven patients (age 18-49 years) suffering from arthrofibrosis were taken at surgery. The mean interval between trauma and arthrolysis was 14.3 months. All samples were stained with haematoxylin and eosin, and monoclonal and polyclonal antibodies were applied for immunohistological localisation of TGF-beta and PDGF. The percentage of both cytokines was then analysed using an image analysis system. Tissue samples with no macroscopic pathology of the synovial tissue from eight patients for anterior cruciate ligament replacement served as controls. Immunostaining for TGF-beta and PDGF was found to be increased in arthrofibrotic tissue. Both cytokines could be detected subsynovially around inflammatory cells. The profibrotic cytokines TGF-beta and PDGF play an important role in the pathogenesis of arthrofibrosis. Both cytokines are key mediators of tissue fibrosis.

[Suspension arthroplasty of the thumb carpometacarpal joint in different views--a questionnaire]. / Die Suspensionsarthroplastik am Daumensattelgelenk--Gute Ergebnisse im Spannungsfeld unterschiedlicher Wertschätzungen.

PURPOSE: Obviously there are different judgements of the results of suspension arthroplasties of the thumb carpometacarpal joint. Consequently, the three main groups involved in therapy were asked about this topic. PATIENTS AND METHODS: 51 patients who had had a suspension arthroplasty on the thumb carpometacarpal joint in the period 1998 - 2006 were questioned. 12 of these patients were operated on both hands (63 operations). A questionnaire sent to 250 family doctors was compared with the results from the 51 patients. Furthermore there was an interview by telephone which included 25 practising specialists (orthopaedicians and surgeons). RESULTS: The results contrasted widely. Concerning the operation, 50 from 51 patients had a high subjective satisfaction. The family doctors had a different view. Nearly 80 % disregarded the success of the operation or they could not judge the chances. Only 50 % of all family doctors arranged for an X-ray or a consultation at a specialist when the patient had continuing problems. The results of the 25 specialists were also not uniform. 50 % of them, especially the hand surgeons, believe in the success of the primary osteoarthritis operation. The high barrier to operations for rhizarthrosis is based on a lack of information.

[Knee injuries of vulnerable road users in road traffic]. / Kniegelenkverletzungen des ungeschützten Verkehrsteilnehmers im Strassenverkehr.

BACKGROUND: The purpose of this study was to assess the risk of knee injuries among vulnerable road users, such as pedestrians, bicyclists and motorcyclists. METHODS: Two different periods (years 1985-1993 and 1995-2003) were compared. Inclusion criteria were furthermore Abbreviated Injury Scale knee 2-3 (AIS(knee)). Technical analysis assessed the type of collision, direction and speed as well as the injury pattern, and different injury scores (AIS, ISS) were examined documented by the accident research unit, which analyses technical and medical data collected shortly after the accident at the scene. This study included 2,580 pedestrians, 2,279 motorcyclists and 4,322 bicyclists from a total number of 22,794 victims in 17,382 accidents. RESULTS: Among vulnerable road users, 2% (196/9181 patients) had serious ligamentous or bony injuries of the knee. The risk of injury was higher for motorcyclists and bicyclists than for pedestrians. Knee injury severity was higher for pedestrians. Over the course of 18 years, the knee injury risk was significantly reduced in more recent times (35%>28%, p<0.0001). Improved aerodynamic design of car fronts reduced the risk for severe knee injuries significantly (p=0.0015). CONCLUSIONS: The highest risk for knee injuries among vulnerable road users is encountered by motorcyclists followed by bicyclists and pedestrians. Over time, the knee injury risk for pedestrians could be significantly reduced due to aerodynamic changes of current car fronts. Further modification of the exterior car design might decrease the risk for knee injuries among vulnerable road users.

Tibial press-fit fixation of the hamstring tendons for ACL-reconstruction.

Press-fit fixation of patellar tendon bone anterior cruciate ligament autografts is an interesting technique because no hardware is necessary to achieve fixation. Up till the present point, there is no biomechanical data available for the tibial press-fit fixation of the hamstring tendons. Hamstring tendons of 21 human cadavers (age: 41.9 +/- 13.1 years) were used. A press-fit fixation with looped semitendinosus and gracilis tendons secured by a tape (T) over a bone bridge, or by a baseball-stitched suture (S), was compared with degradable interference screw fixation (I) in 21 porcine tibiae. The constructs were cyclically strained and subsequently loaded to failure. The maximum load to failure, stiffness, and elongation during cyclical loading were measured. The maximum load to failure was highest for the T-fixation at 970 +/- 83 N, followed by the I-fixation with 544 +/- 109 N, and the S-fixation with 402 +/- 78 N (P < 0.03). Stiffness of the constructs averaged 78 +/- 13 N/mm for T, 108 +/- 18 N/mm for S, and 162 +/- 27 N/mm for I (P < 0.03). Elongation during initial cyclical loading was 2.0 +/- 0.6 mm for T, 3.3 +/- 1.1 mm for S, and 1.4 +/- 0.5 mm for I (S inferior to I and T, P<0.05). Elongation between the 20th and 1,500th loading cycle was lower for T (2.2 +/- 0.7 mm) compared with I (4.1 +/- 2.7 mm) and S (4.8 +/- 0.7 mm; P < 0.001). The T-fixation technique exhibited a significantly higher failure load than the S-, and I- techniques. All techniques exhibited larger elongation during initial cyclical loading than is reported in the literature for grafts with bone blocks. Only one technique (T) showed satisfactory elongation behavior during long-term cyclic loading. Interference screw fixation demonstrated significantly higher stiffness. Only one of the investigated techniques (T) seemed to exhibit adequate mechanical properties necessary for early aggressive rehabilitation programs.

[Gymnastic school sport injuries--aspects of preventive measures]. / Turnunfälle im Schulsport -- Ansätze für präventive Massnahmen.

INTRODUCTION: Gymnastic school sport injuries account for a significant morbidity and mortality among children and adolescents. Preventive issues may be derived from a thorough in-depth analysis of the pattern and circumstances of gymnastic injuries. METHODS: During a school year among 3993 schools in 43 889 classes with 993 056 pupils 2234 school sport injuries have been reported to the Gemeinde Unfall Versicherung (GUV) Niedersachsen, Germany. RESULTS: Gymnastic sport injuries account for 18 % (403 accidents), which is second after ball sports injuries. Regarding the distribution of the gymnastic disciplines, vault was the major discipline with 34 %, followed by floor exercise (21.3 %), mini- and competition trampoline (16.8 %), and parallel bars (8.2 %). The analysis of the type of injury during vault accidents revealed contusion (31 %) as the predominant injury, followed by sprains (15.4 %), and fractures (15.4 %). Floor exercise injuries distributed among distorsions (26.7 %), contusions (18.6 %), muscle tears (14 %). Back injuries especially of the cervical and thoracic spine, accounted for 40 % of all their injuries. Minor head injuries account for 4.7 % of all floor exercise injuries. Mini-trampoline injuries distribute among contusions (30 %), fractures (22.5 %), distorsions (7.5 %). 21.8 % collisions were noted against a box in comparison to 6.8 % in case of the horse. CONCLUSION: Gymnast injuries account for a significant number of all school sport related injuries. Vault and floor exercise account for the vast majority of all injuries, with alarming high numbers of spine injuries during floor exercise and mini-trampoline. A preservation of a high level of attention during a sport lesson, safety measures including appropriate mats and landing zones are mandatory to reduce injuries. Muscle injuries and ankle sprains can be prevented by a prospective proprioceptive training intervention to be implemented in school sports.

Navigated open-wedge high tibial osteotomy: advantages and disadvantages compared to the conventional technique in a cadaver study.

High tibial osteotomy (HTO) is an established therapy for the treatment of symptomatic varus malaligned knees. A main reason for disappointing clinical results after HTO is the under- and overcorrection of the mechanical axis due to insufficient intraoperative visualisation. Twenty legs of fresh human cadaver were randomly assigned to navigated open-wedge HTO (n=10) or conventional HTO using the cable method (n=10). Regardless of the pre-existing alignment, the aim of all operations was to align the mechanical axis to pass through 80% of the tibial plateau (beginning with 0% at the medial edge of the tibial plateau and ending with 100% at the lateral edge). This overcorrection was chosen to ensure a sufficient amount of correction. Thus, the medial proximal tibia angle (MPTA) increased by 9.1+/-2.9 degrees (range 5.2 degrees -12.3 degrees ) on the average after navigated HTO and by 8.9+/-2.9 degrees (range 4.7 degrees -12.6 degrees ) after conventional HTO. After stabilization with a fixed angle implant, the alignment was measured by CT. After navigated HTO, the mechanical axis passed the tibial plateau through 79.7% (range 75.5-85.8%). In contrast, after conventional HTO, the average intersection of the mechanical axis was at 72.1% (range 60.4-82.4%) (P=0.020). Additionally, the variability of the mean corrections was significantly lower in the navigated group (3.3% vs. 7.2%, P=0.012). Total fluoroscopic radiation time was significantly lower in the navigated group (P=0.038) whereas the mean dose area product was not significantly different (P=0.231). The time of the operative procedure was 23 min shorter after conventional HTO (P<0.001). Navigation systems provide intraoperative 3-dimensional real time control of the frontal, sagittal, and transverse axis and may increase the accuracy of open-wedge HTO. Future studies have to analyse the clinical effects of navigation on corrective osteotomies.