bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bone Microarchitecture of the Tibial Plateau in Health and Osteoporosis
Authors: Krause Matthias , Hapfelmeier Alexander , Püschel Klaus , Amling Miachel , Frosch Karl-Heinz 
Published: May 2017

Aims and Objectives: A failure rate of up to 69% of surgically treated tibial plateau fractures in the elderly is attributed among others to the increasing incidence of osteoporosis resulting in renewed immobilization and revision surgery. Hence, ideally implants are fixed in regions with sufficient bone mass. However, data on region-specific structural alterations of the tibial plateau in osteoporosis do not exist. The primary aim of the study was to characterize region-specific changes of the bone structure in patients with osteoporosis compared to skeletally healthy controls. Materials and Methods: In a preclinical case-control study twenty-one human right proximal tibiae from females with postmenopausal osteoporosis (mean age: 84.3±4.9 years) and eight skeletally healthy, premenopausal female controls (45.5±6.9 years) were harvested during autopsy. Histomorphometric parameters were assessed by HR-pQCT (high-resolution peripheral quantitative computed tomography) after digital subdivision into different volumes of interest (VOI) according to a 10-segment classification in three levels of the tibial plateau. In the coronal plane, analysis was performed in the proximal 3 cm from the articular surface. Statistical analysis was based on evolutionary learning using globally optimal regression trees. Results: Skeletally healthy controls showed a better bone structure throughout the whole tibial plateau than osteoporotic patients. In osteoporosis, the greatest bone loss was found in the medio-medial VOI (antero-medio-medial, postero-medio-medial) compared to controls. The lowest bone volume, however, was found in the central VOI (antero-central, postero-central) representing the tibial spine. Trabecular connectivity was severely reduced. Most importantly, in the anterior and posterior 25% of the lateral and medial tibial plateau, the trabecular support and the subchondral lamella thickness itself was severely reduced. Conclusion: The bone structure deterioration of the tibial plateau due to osteoporosis is region-specific. The additional thinning of the subchondral lamella and marked bone loss in the anterior and posterior 25% of the tibial plateau may explain failure of fracture reduction in cases of unilateral plate fixation, specifically in postero-medial fragments. The understanding of region-specific architectural alterations of the tibial plateau may help to improve the long-term, fracture-specific fixation of tibial plateau fractures, especially in osteoporotic patients.
Survival rate after septic total knee arthroplasty- a comparison of two treatment algorithms
Authors: Baier Clemens , Maderbacher Günther , Grifka Joachim , Springorum Hans-Robert 
Published: May 2017

Aims and Objectives: To date there exists no golden standard of treatment of late periprosthetic joint infection. Different forms of treatment comprise single-stage or two-stage or multiple revisions. Respectively, mid- to long-term results are rare. Materials and Methods: We retrospectively analysed 66 patients with septic total knee arthroplasty treated by two different therapy algorithms: Until 2009 patients were treated routinely by implant removal and implantation of an articulating spacer in combination with at least 6 weeks of antibiotic administration. After an antibiotic-free period of two weeks persistent infection was ruled out by punctation. In case of negative antimicrobial cultures after another 14 days patients were treated by reimplantation (n=36, group 1). After 2009 persistent infection was ruled out by open revision and change of the articulating spacer instead of a punctuation. In case of negative antimicrobial cultures after another 14 days patients were treated by reimplantation (n=30, group 2). After a follow-up of 61 months (group 1), respectively 36 months (group 2), patients and their family doctors were contacted by phone concerning the survival rate of the new implant. Results: In group 1 persistent infection was ruled out in every patient by punctuation. During reimplantation tissue samples of 8 patients (22%) showed positive microbiological results again, within 4 patients with a change of the underlying bacteria. After a follow-up of 61 months 31 patients showed no signs of reinfection of their implant and were not operatively revised (86%). In group 2 all patients were treated with open revision and change of the articulating spacer for at least once. 8 patients showed a change of the underlying bacteria during these procedures. During reimplantation tissue samples of 8 patients (27%) showed positive microbiological results again. After a follow-up of 36 months 27 patients showed no signs of reinfection of their implant and were not operatively revised (90%). The difference between both groups was not significant (p>0.05). Concerning the overall complication rate no significant differences between both groups could be found (p>0.05). Conclusion: Concerning reinfection rate we could not detect significant differences between both groups. Patients of group 2 were treated operatively significantly more often and showed a significantly more frequent change of the underlying bacteria. If these results are confirmed in big cohort studies the elaborate treatment algorithm of open revision and change of the articulating spacer might become dispensable.
Subluxation of knees in TKA - a neglected fact? An in vitro study.
Authors: Maderbacher Günther , Springorum Hans-Robert , Grifka Joachim , Baier Clemens , Keshmiri Armin 
Published: May 2017

Aims and Objectives: Correct implant alignment is a well known factor for good functional results and increased implant survival after total knee arthroplasty (TKA). However, in present studies only coronal, sagittal and rotational alignment parameters have been considered, while translational parameters, the relative position between the femur and the tibia in medio-lateral, ventro-dorsal and proximo-distal direction are widely neglected. Due to variable mediolateral, proximodistal and ventrodorsal component placement in TKA, we hypothesised changed relative positions between the femoral and tibial bone resulting in a subluxation of knees after TKA. Materials and Methods: In nine Thiel embalmed whole body cadavers without any history of orthopaedic surgeries, fracutres and osteoarthritis, the relative positions between the femoral and tibial bones were measured between 0 and 90° of flexion before and after TKA (DePuy PFC Sigma, CR, fixed bearing) by means of a navigation system (Brainlab 2.6, Feldkirchen). To compare femoral positions before and after TKA, a paired t-test was used. A two-sided p-value of <0.05 was considered statistically significant. Results: In full extension, the femoral bones shifted 5.7 mm laterally(SD 4.0, p=0.003), and 2.7 proximally (SD 3.1, p=0.030), which decreased up to 90° of flexion to a lateral shift of 3.7 mm (SD 3.5, p=0.006) and proximal shift of 0.9 mm (SD 1.6, p=0.144). The femoral bones were located more dorsal in extension (2.8 mm dorsally (SD 4.8, p=0.113) which changed to a more ventral position in flexion (2.8 mm, SD 4.2, p=0.077). Conclusion: In the present setting, total knee arthroplasty resulted in significant changes of translational positions between the femoral and tibial bones, thus subluxation of knees. Major reasons for that might be a non centered placement of tibial or femoral implants, symmetric implants which do not respect individual anatomy, operative techniques, and large steps between two component sizes. Subluxation might cause an altered tension of the ligaments and consequently change tibiofemoral or patellar kinematics or tensioning of the periarticular soft tissue resulting in pain. However, clinical trials are necessary to evaluate clinical impact of the presented results.
Biomechanical Investigation of Different Preparation Techniques of Tripled Soft Tissue ACL Grafts
Authors: Achtnich Andrea , Föhr Peter , Herbst Elmar , Imhoff Andreas , Braun Sepp 
Published: May 2017

Aims and Objectives: The purpose was to investigate biomechanical properties of different preparation techniques of tripled soft tissue ACL grafts to avoid early mechanical graft failure. It was hypothesized that 1) a graft with a quadrupled femoral portion results in higher load to failure and stiffness compared to a uniformly tripled graft, and 2) a Krackow stitch technique is superior to both baseball stitch and whipstitch technique. Materials and Methods: Forty-eight bovine flexor tendons (eight per group) with a final graft length of 8 cm were used for the present study and randomly assigned to the two graft configuration groups: A) quadrupled femoral portion with a tripled tibial portion, and B) uniformly tripled soft tissue graft. Within the two groups, three different stitching techniques were applied: 1) Whipstitch technique, 2) Krackow stitch, and 3) Baseball stitch. After preconditioning, the grafts were cyclically loaded for 1000 cycles between 50 and 200 N (1 Hz) with consecutive load to failure testing using a constant elongation of 30 mm/min. During biomechnical testing, graft elongation was evaluated with an optical tracking system. For statistical analysis a two-way analysis of variance with a post-hoc Holm-Sidak test was performed. To evaluate the failure mode the Fisher’s exact test was used. The significance level was set at p #CHR: lesslike# 0.05. Results: Considering load to failure, quadrupling the femoral portion of the graft significantly increased the load to failure (p = 0.003) while varying the stitching technique had no influence (p = 0.998). Additionally, graft elongation was lower in group A, but difference was not significant (p = 0.058). Lowest graft elongation was observed when a Krackow stitch was applied, followed by the baseball stitch, and the whipstitch technique (p = 0.035). In group A, all the constructs (graft including sutures) failed at the suture, whereas in group B the failure mode was a slippage of the free femoral graft strand in seven of eight grafts (p = 0.005). Conclusion: When using tripled ACL soft tissue grafts in combination with an extracortical fixation device, the femoral portion should be quadrupled whereas the stitching technique does not have a significant influence on the biomechanical properties. To achieve a higher load to failure with less graft elongation at time zero, the free femoral strand of the tendon graft should be wrapped around the femoral graft tendon loop. This could reduce early graft failure due to slippage of the third free femoral graft strand.
Long-Term Clinical and MRI Results after Refixation of osteochondral Fractures with resorbable Implants
Authors: Rüther Hauke , Raschke David , Frosch Stefan , Wachowski Martin , Seif Ali 
Published: May 2017

Aims and Objectives: Refixation with resorbable implants is a common surgical treatment in patients with an osteochondral fracture of the knee or the upper ankle joint. Up to date there are no studies, which outline long-term outcome of this procedure. As a consequence aim of this study was to evaluate the long-term clinical und MRI results. Materials and Methods: In this study 12 patients were examined 13,9 (#CHR: plusmn# 1,2) years after refixation of an osteochondral fragment of the knee (10) and the upper ankle joint (2) with a mean size of 3.16 cm<sup>2</sup> (#CHR: plusmn# 2,27) by resorbable implants (SmartNail, Conmed). We used eight established clinical scores (VASS, Tegner, Lysholm, McDermott, KSS, WOMAC, AOFAS, FADI+Sports). Furthermore we ascertained integration of bone and cartilage morpholgy by MRI (3 Tesla) using proton-weighted- and cartilage-sensitive double-echo-steady-state (DESS) sequences. To identify a possible osteonecrosis we used T1-weighted sequences with a contrast agent (Gadolinum). The morphologic results were objectified with a modified MRI-Score based on Henderson et al. (2003). Results: After 13,9 (#CHR: plusmn# 1,2) years the patients with an injury of the knee as well as of the upper ankle joint showed good to excellent results (Knee: VASS: 1,3 (#CHR: plusmn# 1,7); Tegener 4,4 (#CHR: plusmn# 1,3); Lysholm 85,7 (#CHR: plusmn# 12,2); McDermott 90,7 (#CHR: plusmn# 8,6); KSS 189 (#CHR: plusmn# 15,9); WOMAC (6,16% (#CHR: plusmn# 8,45)) (Upper Ankle joint: VASS: 2,5 (#CHR: plusmn# 2,5); Tegener 5,5 (#CHR: plusmn# 1,5); Lysholm 87 (#CHR: plusmn# 13), McDermott 88 (#CHR: plusmn# 12); WOMAC (8,54% (#CHR: plusmn# 8,54); AOFAS 75,5 (#CHR: plusmn# 24,5); FADI+Sports 118 (#CHR: plusmn# 18)). There was a good integration of the osteochondral fragment in all cases in the MRI. 5 patients showed moderate subchondral cysts. There were changes of the cartilage contour in all patients. The mean Henderson-Score was 14,4 (#CHR: plusmn# 2,0) (Best: 8, Worst: 32), which correlates with good results. Conclusion: Because of its good clinical and MRI results the refixation by resorbable implants can be recommended to treat osteochondral flakes.
FMS: Relationship between muscul activity in deep squat ans trunk stability pushup
Authors: Kraus. Kornelius 
Published: May 2017

Aims and Objectives: Motor control is described as the internal control and regulation processes which facilitate movements. Scientists divide motor control into the function of stability and the movement to maintain balance in locomotion. The FMS is used to analyze the motor behavior of muscle slings on the one hand, and to estimate injury risk on the other hand. Yet, the true extent of the FMS’ diagnostic information remains unclear. The low intensity level of the FMS items causes low tension within the motor network. Based on Hennemen’s size principle, this is a clear indicator for the activation of slow-twitch fibers in the muscle. A possible relationship between movement and stability function of muscle slings has yet to be examined. Therefore, the aim of this investigation was to shed light on the motor behavior of dynamic and isometric muscle activity as well as the examination of average muscle activity when performing the items deep squat (DS) and trunk stability pushup (TSPU). Materials and Methods: Data from 16 collegiate athletes (22.1±1.5yrs) with various sports histories was analyzed. The data analysis was based on Kendall’s tau correlation coefficient. The items DS and TSPU were rated via an ordinal ranking system ranging from 0 (pain) to 3 (adequate). Muscle activity was recorded with a new EMG device at a rate of 25 Hz (Myontec Ltd, Kuopio, Finland). In a concurrent pilot study the reliability of this device was examined with a progressive loaded squat protocol (50 up to 125% BW). It indicated almost perfect reliability for the quad/ham balance, quadriceps distribution (r< 0.9, CV:3-5%) and high reliability for the hamstrings (r >0.8, CV:<10%). Results: Strong relationships between the quad/ham balance (r=0.7, p<0.01) and quadriceps distribution (r=0.6, p<0.03) in DS and TSPU were identified. The connection between hamstring muscle activity balance was low (r< 0.2, p>0.5). In both items, the muscle contractions were dominated by the activation of the quadriceps (79% vs. 21% hamstrings). Additionally, the average muscle activity was 4 times higher in a loaded squat (100% BW) than it was in DS. Generally, DS was rated as follows: score 3 (3 times) and score 2 (13 times). For the item TSPU score 3 was given 14 times and score 2 was given 2 times. Conclusion: The relationship between dynamic and static motor behavior of the quadriceps supports the connection between the stabilizing and movement function of muscle slings. The low intensity corresponds with the slow EMG activity in DS, which is an indicator for the activation of mainly slow twitch muscle fibers. This scientific innovation is relevant for practitioners as it establishes the diagnostic value of the FMS. Based on this evidence, the FMS provides information with regards to low tension motor behavior. It is unlikely that this information is specific enough to estimate injury risk or performance because when it comes to return to sport decisions, it is also important to obtain information of motor control associated with fast-twitch fibers.
Pathobiochemistry of arthrofibrotic remodeling
Authors: Faust Isabel , Traut Philipp , Knappe Cornelius , Hendig Doris 
Published: May 2017

Aims and Objectives: Arthrofibrosis is defined as painful impairment of joint flexibility due to fibrotic tissue remodeling after joint trauma or surgery. The incidence of arthrofibrosis after knee replacement surgery is 5 to 10%. Although conventional therapeutic approaches as for instance mobilization and physiotherapy are applied, an effective and causative therapeutic regimen is not known. Materials and Methods: To characterize arthrofibrotic remodeling of the extracellular matrix, to develop new therapeutic approaches and to define diagnostic biomarkers and therapeutic targets, understanding of biochemical principles is urgently required. Fibrotic remodeling was described in several tissues, whereas synovial fibrosis is one of the least investigated fibrotic disorders. Nevertheless, molecular key events in fibrosis seem to be the same and are initiated by exogenic or endogenic tissue damage and differentiation of resident fibroblasts of the connective tissue to myofibroblasts. Known inductors of myofibroblast differentiation are fibrotic growth factors, which are secreted by platelets, damaged tissue and inflammatory cells, as well as mechanical strain. Research studies concerning cardiac fibrosis in tako-tsubo cardiomyopathy also define emotional stress and sympathicotonic destabilization as profibrotic stressors. Myofibroblasts generate contractile forces and synthesize extracellular matrix components, so that scar tissue accumulates. While myofibroblasts disappear by apoptosis in physiological wound healing, they persist in fibrosis. Results: Recently, we could demonstrate that increased expression of human xylosyltransferase (XT)-I, an enzyme which catalyzes the rate limiting step in proteoglycan glycosylation, is linked to abnormal extracellular matrix remodeling. Serum XT activity reflects proteoglycan synthesis rate and is known as fibrosis biomarker in liver fibrosis or scleroderma. Our data also indicate that XT-I is a cellular key mediator of arthrofibrosis. However, we suggest that molecular changes based on arthrofibrosis are, due to local restriction of the affected joint by the blood-synovial-barrier, not detectable in human serum. Currently, we study synovial XT activity of arthrofibrosis patients and controls in a multicenter study. Conclusion: In summary, we give insights into the complex pathobiochemistry of arthrofibrosis as well as current research projects. A deeper characterization of the involved mechanisms might not only contribute to control and inhibit fibrotic remodeling by interfering with components of fibrotic signal cascades but also to establish new therapeutic strategies.
Analysis of graft maturation after autologous chondrocyte implantation with T2 mapping
Authors: Niethammer Thomas R. , Loitzsch Ansgar , Pietschmann Matthias F. , Müller Peter E. , Horng Annie 
Published: May 2017

Aims and Objectives: It has been shown in numerous clinical studies that matrix-based autologous chondrocyte implantation (mb-ACI) leads to good clinical results in the medium-term course. But chondrogenic development of ACI grafts and the time of graft maturation are still unclear. The aim of this study was to investigate the graft maturation after mb-ACI with T2 mapping in the postoperative course of four years. Materials and Methods: In a total of 90 patients could be included after matrix-based autologous chondrocyte transplantation of the knee. All cartilage defects were treated with NOVOCART® 3D. The evaluation of the ACI grafts was conducted after 3, 6, 12, 24, 36 and 48 months by MRI. The T2 relaxation time values of the ACI graft and healthy native cartilage areas were determined to assess graft maturation using T2 mapping. MOCART score were used for morphological evaluation of ACI grafts. Results: The T2 relaxation time of ACI grafts showed a significant improvement during the postoperative course at all time points. The T2 relaxation improved from 48.0 ms after 3 months to 34.6 ms after four years. We found a significant influence of the patient’s age and the defect localization on the T2 relaxation time measuring. It could be detected an increasing integration of the ACI grafts into the healthy surrounding cartilage. No significant differences between the T2 relaxation time of ACI grafts and the surrounding healthy cartilage were found after 12 months postoperatively. Conclusion: Graft maturation after ACI in the knee joint needs at least 1 year, with ongoing adjustment of the T2 relaxation time values compared with native surrounding cartilage. Regarding the age and defect localization, significantly worse T2 relaxation times of the ACI grafts could be found with higher age and in cases with treated patellar defects.
The huddle-technique app - a new instrument imaging knee-instability of young high performance football players. Comparison of measured angles, KT1000, KLT and subjektiv instability
Authors: Braun Philipp-Johannes , Stoffels Thomas , Hünnebeck Sophia , Trendelbern Jenny , Stengel Dirk 
Published: May 2017

Aims and Objectives: Is there a correlation between measured frontal plane projection angle, KT1000, KLT and subjektiv instability recognized by player or examiner in a cohort of 101 young high performance football players. We want to establish a reproducible tool that recognizes knee instability in a dynamic movement to prevent knee injury in young high performance athletes. Materials and Methods: Rupture of anterior cruciate ligament (ACL) is a serious knee injury. Several epidemiological studies have shown a correlation between coordination, neuromuscular control and incidence of ACL injuries. In a prospective study of 101 young high performance football players we measured the frontal plane projection angle (FPPA) in drop test with the huddle-technique app. Furthermore we captured subjektiv instability in drop test, single hop test and figure of eight test as well as basic instability criteria as lachmann test, pivot shift test, KT 1000 and KLT. Results: Low FFPA angles (valgus knee) in drop test correlate with higher subjective knee instability recognized by players as well as by examiner. KT 1000 and KLT as a basic instability criteria are not reproducible relating to the subjective instability. Furthermore we investigate a correlation between measured instability with the huddle-technique app, shooting foot and shape of muscular system. Conclusion: The huddle-technique app is a new instrument which gives us an advise of knee instability of young high performance football players. With measuring the FFPA angle in drop test we have a reproducible tool that recognizes instability in a dynamic movement. Our aim is to identify high risk players and modify their movement pattern to avoid knee injury, especially rupture of anterior cruciate ligament. The FFPA angle measured with huddle-technique app additionally can help us to supervise success of special training programs.