Cerclage performance analysis - a biomechanical comparison of different techniques and materials.

BACKGROUND: Wire cerclages play a fundamental role in fracture fixation. With an increasing variety of designs being commercially available the question arises which cerclage should be used. This study investigates the biomechanical properties of metallic and non-metallic cerclages and their different application-types. Furthermore, potential influence of muscular interposition between bone and cerclage constructs was tested. METHODS: Samples of the following four different cerclage types were tested on 3D printed models of human humeri as well as on human cadaveric humeri with and without muscular interposition: Titanium Cable Cerclage (CC), Steel Wire Cerclage (SWC), Suture Tape (ST), Suture Tape Cerclage (STC) with both single- (sSTC) and double-loop application (dSTC). A preinstalled self-locking mechanism secured by the provided tensioner in the STCs being the main difference to the STs. Cyclic loading was performed to 1 kN and then linearly to a maximum load of 3 kN. Statistical analysis was performed using either one-way ANOVA and post-hoc Tukey or Kruskal-Wallis and post-hoc Dunn test depending on normalization of data (p < 0.05). RESULTS: Whilst all cerclage options could withstand high loads during failure testing, only within the CC and dSTC group, all samples reached the maximal testing load of 3000 N without any failure. The SWC reached 2977.5 ± 63.6 N, the ST 1970.8 ± 145.9 N, and the sSTC 1617.0 ± 341.6 N on average. Neither muscular interposition nor bone quality showed to have a negative influence on the biomechanical properties of the cerclage constructs, presenting no significant differences. CONCLUSION: All tested cerclage constructs produce reliable stability but differ in their resulting compression forces, in a simplified fracture model. Therefore, non-metallic cerclage alternatives can provide similar stability with less compression and stiffness to metallic cable constructs, but they may offer several advantages and could possibly provide future benefits. Especially, by offering more elasticity without losing overall stability, may offer a biologic benefit. Installing any cerclage constructs should be performed carefully, especially if poor bone quality is present, as the tightening process leads to high forces on the construct.

Union rates and functional outcome of double plating of the femur: systematic review of the literature.

BACKGROUND: The optimal treatment strategy for the surgical management of femur fractures and non-unions remains unknown. The aim of this study is to assess union rates, complications and outcome after femoral double plating. Treatment of shaft, distal, periprosthetic fractures and pathological proximal femur fractures as well as femoral non-unions with double plating were evaluated. METHODS: A systematic review according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement was conducted. Published literature reporting on the treatment and clinical outcome of femoral fractures and non-unions with double plating was identified. In total, 24 studies with 436 cases of double plating, 64 cases of single plating, 84 cases of intramedullary nailing (IM), and 1 interfragmentary screw treatment met the inclusion criteria of this systematic review. The evaluated literature was published between 1991 and 2020. RESULTS: Double plating of femoral fractures achieved high healing rates and few complications were reported. It displayed significantly less intraoperative haemorrhage, shorter surgery time reduced risk of malunion in polytraumatised patients when compared to IM. Fracture healing rate of double-plating distal femoral fractures was 88.0%. However, there were no significant differences regarding fracture healing, complication or functional outcome when compared to single plating. Treatment of periprosthetic fractures with double plating displayed high healing rates (88.5%). Double plating of non-unions achieved excellent osseous union rates (98.5%). CONCLUSIONS: The literature provides evidence for superior outcomes when using double plating in distal femoral fractures, periprosthetic fractures and femoral non-unions. Some evidence suggests that the use of double plating of femoral fractures in polytraumatised patients may be beneficial over other types of fracture fixation. LEVEL OF EVIDENCE: IV.

Primary stability of single-stage revision reconstruction of the anterior cruciate ligament in case of failure of dynamic intraligamentary stabilization depends on implant position during ACL repair.

INTRODUCTION: The object of this study was to evaluate the primary stability of tibial interference screw (IFS) fixation in single-stage revision surgery of the anterior cruciate ligament (ACL) in the case of recurrent instability after ACL repair with dynamic intraligamentary stabilization (DIS), dependent on the implant position during DIS. MATERIALS AND METHODS: Tibial aperture fixation in ACL reconstruction (ACL-R) was performed in a porcine knee model using an IFS. Native ACL-R was performed in the control group (n = 15). In the intervention groups DIS and subsequent implant removal were performed prior to single-stage revision ACL-R. A distance of 20 mm in group R-DIS1 (n = 15) and 5 mm in group R-DIS2 (n = 15) was left between the joint line and the implant during DIS. Specimens were mounted in a material-testing machine and load-to-failure was applied in a worst-case-scenario. RESULTS: Load to failure was 454 ± 111 N in the R-DIS1 group, 154 ± 71 N in the R-DIS2 group and 405 ± 105 N in the primary ACL-R group. Load-to-failure, stiffness and elongation of the group R-DIS2 were significantly inferior in comparison to R-DIS1 and ACL-R respectively (p < 0.001). No significant difference was found between load-to-failure, stiffness and elongation of R-DIS1 and the control group. CONCLUSION: Primary stability of tibial aperture fixation in single-stage revision ACL-R in case of recurrent instability after DIS depends on monobloc position during ACL repair. Primary stability is comparable to aperture fixation in primary ACL-R, if a bone stock of 20 mm is left between the monobloc and the tibial joint line during the initial procedure.

Adjustable buttons for ACL graft cortical fixation partially fail with cyclic loading and unloading.

PURPOSE: Despite good initial pullout strength, it is unclear whether adjustable button (AB) devices for anterior cruciate ligament (ACL) soft-tissue graft fixation, which are based on the Chinese finger trap technique, resist cyclic loading. Furthermore, they have never been tested in a cyclic protocol including complete unloading. It was hypothesized, that the displacement of AB devices with the Chinese finger trap technique would be greater than that of continuous suture loop devices and other available AB mechanisms in a cyclic loading with complete unloading protocol. METHODS: ACL reconstruction was performed in a porcine knee model using three different types of cortical fixation devices: two different AB devices that use the Chinese finger trap design, one AB device that uses a locked suture loop mechanism and two different continuous loop devices as control groups (n = 40). Specimens were mounted in a material-testing machine (Instron Inc.) that permitted 2500 loading and complete unloading cycles to a maximum of 250 N, as well as continuous elongation recording. A one-way ANOVA was performed for statistical analysis. RESULTS: The displacement of ABs with a Chinese finger trap loop (mean 8.1; SD 1.5 mm and mean 6.1; SD 1.4 mm) was significantly greater than that of AB with a locked suture loop (mean 4.7; SD 1.0 mm; p < 0.05) and devices with a continuous loop (mean 4.1; SD 0.5 mm and mean 4.4, SD 0.3 mm; p < 0.01). No significant differences were detected between the ABs with a locked suture loop and the continuous loops. CONCLUSION: Cyclic loading and unloading of AB using the Chinese finger trap technique leads to significantly greater construct lengthening compared with other devices. Complete unloading of the ACL is very likely to occur during rehabilitation after ACL reconstruction. Lengthening of the AB device due to cyclic loading might be a potential mode of failure of the ACL graft fixation. Therefore, when using an AB femoral fixation technique, a locked suture loop design or a careful rehabilitation protocol should be considered.

[Stimulation of fracture healing by growth factors and cell-based technologies]. / Stimulation der Frakturheilung durch Wachstumsfaktoren und zellbasierte Technologien.

Bone has the special capability to completely regenerate after trauma and to re-establish its original geometry and biomechanical stability corresponding to the pretrauma conditions. Nevertheless, in daily clinical practice impaired fracture healing and nonunions are regular complications as a result of inadequate mechanical stability and/or insufficient biological processes around the fracture region. Since the beginning of the millennium, intensive research on the physiological processes in bone healing as well as the production and clinical administration of growth factors have enabled the possibility to improve the local biological processes during fracture healing by osteoinduction. Although the initial clinical results, particularly of bone morphogenetic proteins, in fracture healing were promising, growth factors did not become established for unrestricted use in the clinical application. Currently, additional growth factors are being investigated with respect to the potential supportive and osteoinductive characteristics for enhancement of fracture healing and possible clinical applications. Furthermore, the development of cell-based technologies is another promising approach to positively stimulate fracture healing. In addition to the gold standard of autologous bone grafting, harvesting of mesenchymal stroma cells by aspiration has gained in importance in recent years. Allogeneic bone cell transplantation procedures and in particular gene therapy are promising new strategies for the treatment of disorders of fracture healing. This review gives an overview of present and future possibilities for modulation of fracture healing by growth factors and cell-based technologies.

[Bilateral well-leg compartment syndrome in a child after abdominal trauma : A review of the literature and treatment recommendations illustrated by a case study]. / Bilaterales Kompartmentsyndrom der Unterschenkel des Kindes nach Abdominaltrauma : Eine Literaturübersicht und Handlungsempfehlungen, veranschaulicht an einem Fallbeispiel.

This article reports a case of a bilateral well leg compartment syndrome (WLCS) in a 9-year-old girl who presented to the emergency room 24 h after blunt abdominal trauma and liver laceration. The abdomen was already packed on presentation. The patient presented a manifest compartment syndrome of both lower legs 48 h after the second look surgery and removal of the packing. Both tibial anterior and peroneal compartments had to be partially resected. In an analysis of literature only five cases of WLCS after surgery in a supine position were found. The young age of the patient and the intra-abdominal packing were identified as risk factors for increased intra-abdominal pressure and reperfusion was suspected to be the cause of the lower leg compartment syndrome.

[Outcome after surgical treatment of calcaneal fractures]. / Outcome nach operativer Therapie von Kalkaneusfrakturen.

BACKGROUND: After controversial discussions in the literature about therapy regimens for calcaneal fractures, a retrospective study of patients operatively treated in a maximum care trauma center was conducted. OBJECTIVE: Investigation of the influencing factors on the treatment quality of operatively treated patients with calcaneal fractures. MATERIAL AND METHODS: Between 2005 and 2013 a total of 90 patients with calcaneal fractures were surgically treated in this hospital with locking plate osteosynthesis. A total of 48 patients with 55 fractures were retrospectively investigated. The assessment with respect to posttraumatic arthrosis was made radiologically and Böhler's and Gissane's angles were also determined. Clinically AOFAS and SF-36 scores were documented. The results were statistically tested with respect to possible risk factors. RESULTS: A total of 9 patients (18.8%) were found with complications necessitating operative revision, with 8 patients requiring subtalar arthrodesis and 1 patient with a deep wound infection. Nicotine abuse and a long interval between trauma and reconstructive surgery were identified as factors that influenced the development of wound healing problems. The average AOFAS score was 68 points and the SF-36 was 58.86 points. A poor result in the scores was caused by the development of symptomatic arthritis and the type of insurance. In this cohort factors, such as age and complexity of fractures were not correlated with a poor result. CONCLUSION: In this patient collective nicotine abuse and a long interval between trauma and surgery were risk factors for development of wound infections. Other factors with an influence on the outcome were the postoperative development of arthritis and the type of health insurance; however, patient age had no impact on the outcome.

Phase coexistence and electric-field control of toroidal order in oxide superlattices.

Systems that exhibit phase competition, order parameter coexistence, and emergent order parameter topologies constitute a major part of modern condensed-matter physics. Here, by applying a range of characterization techniques, and simulations, we observe that in PbTiO3/SrTiO3 superlattices all of these effects can be found. By exploring superlattice period-, temperature- and field-dependent evolution of these structures, we observe several new features. First, it is possible to engineer phase coexistence mediated by a first-order phase transition between an emergent, low-temperature vortex phase with electric toroidal order and a high-temperature ferroelectric a1/a2 phase. At room temperature, the coexisting vortex and ferroelectric phases form a mesoscale, fibre-textured hierarchical superstructure. The vortex phase possesses an axial polarization, set by the net polarization of the surrounding ferroelectric domains, such that it possesses a multi-order-parameter state and belongs to a class of gyrotropic electrotoroidal compounds. Finally, application of electric fields to this mixed-phase system permits interconversion between the vortex and the ferroelectric phases concomitant with order-of-magnitude changes in piezoelectric and nonlinear optical responses. Our findings suggest new cross-coupled functionalities.

The impact of different peripheral suture techniques on the biomechanical stability in flexor tendon repair.

PURPOSE: Flexor tendon repair consists of circumferential peripheral sutures in combination with core sutures to avoid fraying and reduces the exposure of suture material on tendon surface. The peripheral suture adds up to a tenfold increase of the biomechanical stability compared to the core suture alone. The purpose of our study was to determine the most favourable peripheral repair technique for tendon repair. METHODS: Seventy-two porcine flexor tendons underwent standardized tenotomy and repair using one of the following six methods (n = 12): simple-running (SR), simple-locking (SL), Halsted-mattress (HM), lin-locking (LL), Lembert-mattress (LM), and Silfverskiöld cross-stich (SCS) suture technique. The SL- suture was placed 2 mm; the HM, LM, SC, and LL suture were placed 5 mm from the tendon gap. The SR suture was placed 1, 2, and 3 mm from tendon ends; no additional core suture was applied. For cyclic testing (1000 cycles), elongation was calculated; for load to failure construct stiffness, yield load and maximum load were determined. RESULTS: The mean cyclic elongation for all tested suture techniques was less than 2 mm; there was no significant difference between the groups regarding elongation as well as yield load. The HM, LM, SCS, and LL suture techniques presented significantly higher maximum loads compared to the SR- and SL-sutures. The 3 mm SR showed significantly higher maximum loads compared to the 2 and 1 mm SR. CONCLUSIONS: Beside the distance from tendon gap, the type of linkage of the suture material across and beneath the epitendineum is important for biomechanical stability. Simple-running suture is easy to use, even with a slight increase of the distance from tendon gap significantly increases biomechanical strength. For future repairs of flexor tendon injuries, 3 mm stitch length is highly recommended for simple peripheral suture, while the Halsted-mattress suture unites the most important qualities: biomechanically strong, most part of suture material placed epitendinous, and not too complicated to perform.

[Operative treatment in orthopedics and trauma surgery : Are more operations carried out in Germany?] / Operative Versorgung in Orthopädie und Unfallchirurgie : Wird in Deutschland immer mehr operiert?

BACKGROUND: Since 2005, when the Diagnosis-Related Group (DRG) system was introduced, an increasing number of surgical procedures have been reported in Germany. In particular, the numbers of elective arthroplasty and spinal surgery procedures have been controversial. OBJECTIVES: The focus of this study was analyzing the development of spinal surgery, arthroplasty, and fracture management. MATERIALS AND METHODS: We analyzed the database for all musculoskeletal operating procedure codes (OPS codes 5­78 to 5­86) from 2005 to 2013 collected by the German Federal Statistical Office. RESULTS: With an increase in total patient numbers of 12.8%, there was a rise in in-patient musculoskeletal procedures of 43.5%; the highest increase in procedures was found in spinal surgery (130%). Despite an ageing population, the numbers of hip- and knee arthroplasty procedures initially decreased after 2011 and after 2009 respectively. The number of osteosyntheses showed a slight increase (16%), whereas the number of (elective) implant removals declined (-7%). An increase in novel techniques was noticeable, such as locked plate osteosynthesis (251%), shoulder arthroplasty (402%) or the use of bone substitutes in spinal surgery (+2,011%). CONCLUSIONS: Despite generally increasing volume growth, the numbers of hip and knee arthroplasty cases decreased. In addition to an ageing population and potential economic incentives, technical innovations and new implant systems should be considered when discussing increasing case numbers.

Converting round tendons to flat tendon constructs: Does the preparation process have an influence on the structural properties?

PURPOSE: The structural properties of hamstring tendon grafts were evaluated in a porcine model, after processing it to a flat shape, to better replace or augment anatomic flat structures (e.g. ACL, MPFL or MCL). METHODS: In this biomechanical study, porcine flexor tendons were used which have a comparable shape to semitendinosus and gracilis tendons. One part of the tendon was prepared to a flat tendon construct by splitting the tendon longitudinally with a knife to half of the diameter of the tendon. The semi-split tendon was scratched out to a flat shape. The other matched part was tested in its original round shape. The tendons (n = 40) have been fixed in a uniaxial testing machine (Zwick/Roell) by cryo-clamps after preparing the fixed ends by 2-0 polyester sutures (2-0 Ethibond® EXCEL, Ethicon, Somerville, NJ). In every specimen, there was a free 60-mm tendon part between both clamps. The tendons have been loaded to failure to evaluate typical biomechanical parameters such as stiffness, yield load and maximum load. RESULTS: No statistically significant differences (n.s.) regarding stiffness, yield load and maximum load between natively round and processed flat tendons could be detected. CONCLUSION: A prepared flat-shaped tendon does not show any different structural properties compared with an original round tendon. Therefore, a flat tendon seems to be a biomechanical stable graft option for anatomic reconstruction or augmentation of injured natively flat-shaped structures such as MCL, MPFL or ACL.

High-resolution MRI (3T-MRI) in diagnosis of wrist pain: is diagnostic arthroscopy still necessary?

INTRODUCTION: 3T MRI has become increasingly available for better imaging of interosseous ligaments, TFCC, and avascular necrosis compared with 1.5T MRI. This study assesses the sensitivity and specificity of 3T MRI compared with arthroscopy as the gold standard. PATIENTS AND METHODS: Eighteen patients were examined with 3T MRI using coronal T1-TSE; PD-FS; and coronal, sagittal, and axial contrast-enhanced T1-FFE-FS sequences. Two musculoskeletal radiologists evaluated the images independently. Patients underwent diagnostic arthroscopy. RESULTS: The classifications of the cartilage lesions showed good correlations with the arthroscopy findings (κ = 0.8-0.9). In contrast to the arthroscopy, cartilage of the distal carpal row was very good and could be evaluated in all patients on MRI. The sensitivity for the TFCC lesion was 83%, and the specificity was 42% (radiologist 1) and 63% (radiologist 2). For the ligament lesions, the sensitivity and specificity were 75 and 100%, respectively, with a high interobserver agreement (κ = 0.8-0.9). DISCUSSION: 3T MRI proved to be of good value in diagnosing cartilage lesions, especially in the distal carpal row, whereas wrist arthroscopy provided therapeutic options. When evaluating the surgical therapeutical options, 3T MRI is a good diagnostic tool for pre-operatively evaluating the cartilage of the distal carpal row.

[Extracorporal shock wave therapy for the treatment of pseudarthrosis : New experiences with an old technology]. / Extrakorporale fokussierte Stoßwellentherapie zur Behandlung von Pseudarthrosen : Neue Erfahrungen mit einer alten Technologie.

BACKGROUND: Between 5 and 10 % of all fractures show disturbed healing or nonunion formation. Extracorporeal shock wave therapy (ESWT) has been described as a non-surgical treatment option. Even though the outcome has shown promising results, the procedure is not commonly used in clinical practice. The purpose of this study was to analyze the union rate of pseudarthrosis and the cost savings after ESWT. METHODS: In this study 42 nonunions were treated with shock waves (LithSpaceOrtho, JenaMedtech). The follow up examinations were performed over a period of six months. Outcome measurement included radiological fracture union and pain (VAS). The study group contained 39 pseudarthrosis in the six-week follow-up (93 %), 41 after three months (98 %) and 41 after six months (98 %). RESULTS: After six weeks, 13 % of patients showed fracture union. After three months 61 % and after six months 73 % of the fractures were completely healed. The fracture healing was significantly lower in older nonunions. All patients presented significantly lower pain levels six weeks after ESWT. Shock wave treatment of all 42 pseudarthrosis made up less than one quarter of the overall operative costs. CONCLUSION: We established the ESWT as an important treatment option for fracture nonunion in our clinic. Considering the selection of patients in this study with a high mean time from injury to ESWT and multiple prior operations, the fracture healing rate of 73 % after ESWT is comparable with operative healing rates of nonunions. Further prospective, randomized and controlled studies are needed to show the effectiveness of ESWT in the treatment of nonunions on a higher level of evidence and to identify pseudarthrosis that particularly responds to the EWST.

Staphylococcus aureus develops increased resistance to antibiotics by forming dynamic small colony variants during chronic osteomyelitis.

OBJECTIVES: Staphylococcus aureus osteomyelitis often develops to chronicity despite antimicrobial treatments that have been found to be susceptible in in vitro tests. The complex infection strategies of S. aureus, including host cell invasion and intracellular persistence via the formation of dynamic small colony variant (SCV) phenotypes, could be responsible for therapy-refractory infection courses. METHODS: To analyse the efficacy of antibiotics in the acute and chronic stage of bone infections, we established long-term in vitro and in vivo osteomyelitis models. Antibiotics that were tested include ß-lactams, fluoroquinolones, vancomycin, linezolid, daptomycin, fosfomycin, gentamicin, rifampicin and clindamycin. RESULTS: Cell culture infection experiments revealed that all tested antibiotics reduced bacterial numbers within infected osteoblasts when treatment was started immediately, whereas some antibiotics lost their activity against intracellular persisting bacteria. Only rifampicin almost cleared infected osteoblasts in the acute and chronic stages. Furthermore, we detected that low concentrations of gentamicin, moxifloxacin and clindamycin enhanced the formation of SCVs, and these could promote chronic infections. Next, we treated a murine osteomyelitis model in the acute and chronic stages. Only rifampicin significantly reduced the bacterial load of bones in the acute phase, whereas cefuroxime and gentamicin were less effective and gentamicin strongly induced SCV formation. During chronicity none of the antimicrobial compounds tested showed a beneficial effect on bone deformation or reduced the numbers of persisting bacteria. CONCLUSIONS: In all infection models rifampicin was most effective at reducing bacterial loads. In the chronic stage, particularly in the in vivo model, many tested compounds lost activity against persisting bacteria and some antibiotics even induced SCV formation.

Surgical treatment of acute acromioclavicular joint dislocations: hook plate versus minimally invasive reconstruction.

PURPOSE: This study was performed to compare the clinical results of a minimally invasive technique for acute acromioclavicular (AC) joint dislocation repair with the traditional hook plate fixation. METHODS: Forty-four patients with an acute (within 2 weeks after trauma) complete AC joint separation (35 male, nine female; median age 36.2 years, range 18-56) underwent surgical repair with either a minimally invasive AC joint repair or a conventional hook plate. Functional outcome was evaluated using the Constant-Murley Score (CMS), the TAFT score and the AC joint instability score (ACJI). Radiographic evaluation was performed with bilateral anterior-posterior (a.p.) stress and Alexander views. RESULTS: All patients were available after a median follow-up of 32 months (range 24-51). There were no significant differences in the mean CMS, Taft score and the ACJI between the two groups. The radiological assessment revealed no significant difference in the coracoclavicular distance. In both groups, a slight loss of reduction was observed. Periarticular ossification was seen in 11 patients of the minimally invasive AC joint repair and eight patients of the hook plate group but this did not affect the final outcome. Hook plates were removed after a median interval of 11.9 weeks (range 10-13). CONCLUSION: Good clinical results can be achieved with both minimally invasive AC joint repair and hook plate fixation. However, in the hook plate group a second operation is mandatory for plate removal. LEVEL OF EVIDENCE: III.

Evaluation of biomechanical properties: are porcine flexor tendons and bovine extensor tendons eligible surrogates for human tendons in in vitro studies?

INTRODUCTION: Porcine flexor tendons, bovine extensor tendons, and human (semitendinosus) tendons are frequently used as substitutes for human ACL grafts in biomechanical in vitro studies. This study compares the biomechanical properties and structural differences of these tendons. MATERIALS AND METHODS: In this biomechanical study, fresh-frozen porcine flexor tendons, bovine extensor tendons, and human semitendinosus tendons were used (n = 36). The tendons were mounted in a uniaxial testing machine (Zwick/Roell) with cryo-clamps, leaving a 60 mm tendon part free between the two clamps. Specimens have been loaded to failure to evaluate the biomechanical parameters stiffness, yield load, and maximum load. A Total Collagen Assay Kit was used to detect differences in the total collagen type I concentration (n = 30). A one-way ANOVA was performed to detect differences in the means. The significance level was set at p < 0.05. RESULTS: There were no significant differences in the stiffness between the groups (bovine 194 ± 43 N/mm, porcine 211 ± 63 N/mm, and human cadaveric 208 ± 58 N/mm). The yield and maximum loads were high (>1000 N) in all groups, but they were significantly increased in both animal specimens (means of 1681-1795 N) compared with human cadaveric specimen (means of 1289-1406 N; p < 0.01). No difference in the collagen type I concentration was detected (N.S.). CONCLUSION: Porcine flexor and bovine extensor tendons are eligible substitutes with similar stiffness and high failure loads compared with human cadaveric semitendinosus tendons in in vitro studies.

[Implant augmentation in pelvic surgery. Options and technique]. / Implantataugmentation am Becken. Optionen und Technik.

BACKGROUND: Osteoporotic fractures of the pelvis are an increasing problem in trauma surgery. Sufficient implant anchorage is reduced due to the poor bone stock; however, early mobilization is especially necessary for geriatric patients in order to prevent additional complications. MATERIAL AND METHODS: Implant augmentation may be one technique to increase implant anchorage and stability in osteoporotic bone. This procedure is currently used in the treatment of osteoporotic fractures of the dorsal pelvic ring. Beside the augmentation of iliosacral screws in the treatment of sacral insufficiency fractures, cement augmentation with lumbar or sacral pedicle screws is used for increased stability. INDICATIONS AND RISKS: Implant augmentation in pelvic surgery should be indicated crucially due to the specific risks of the procedure. Cement leakage and heat generation during cement curing (when PMMA--polymethylmetacrylate--cement is used) can compromise neurovascular structures. Potential complications like cement embolism are possible. CONCLUSION: The use of special implants (cannulated and perforated screws) as well as intraoperative navigation and 3D imaging increase patient safety and help to make implant augmentation a low risk procedure.

[Hip fracture prosthetics in German trauma surgery. State of the art]. / Frakturhüftendoprothetik in der deutschen Unfallchirurgie. Eine Standortbestimmung.

BACKGROUND: To improve patient safety and quality in joint arthroplasty a certification of arthroplasty centers (EndoCert©) and a German arthroplasty register (EPRD) have been implemented. This should guarantee a long-term improvement in documentation of arthroplasty in the future. Although the stages of operations in elective and trauma-associated joint arthroplasty are comparable, the surgical preconditions are often quite different. As required by the German Society of Trauma Surgery (DGU) this study analyzed the current situation with respect to the proportion of fracture-associated joint arthroplasties among the total volume carried out in Germany. MATERIAL AND METHODS: A uniform internet-based questionnaire was sent to all listed trauma centers in Germany by the central office of the DGU. In addition any information regarding hip joint arthroplasty in 2011 was collected from the Federal Statistical Office of Germany. RESULTS: The questionnaire was returned by 324 (47 %) out of 690 of the trauma centers contacted. A total of 34,135 total hip arthroplasties (THA) and 26,753 total knee arthroplasties (TKA) were carried out in 2011 by these clinics. The absolute numbers for total endoprosthesis replacement cited by the trauma centers were 5718 THAs and 3829 TKAs. According to the data from the Federal Statistical Office of Germany 131,966 hip fractures were registered in 2011, including 69,582 femoral neck fractures (patient age >19 years) and 62,384 pertrochanteric fractures. From a total number of THAs of approximately 200,000 in Germany 47,695 (approximately 25 %) of these were associated with trauma. DISCUSSION: The data analyzed in this study and the results obtained from known literature sources demonstrate that THA is the most frequently performed procedure in trauma management of femoral neck fractures. Because of the ubiquitous and high incidence and the need for emergency treatment due to correlated risks and complications of delayed treatment, a high and standardized around the clock (24 h and 7 days a week) treatment option is mandatory. Long waiting times to treatment or transfer are inacceptable due to the increased mortality and complications.

[Dynamic intraligamentary stabilization of the anterior cruciate ligament. Operative technique and short-term clinical results]. / Dynamische intraligamentäre Stabilisierung des vorderen Kreuzbandes. Operationstechnik und klinische Kurzzeitergebnisse.

BACKGROUND: Reconstruction of tears in the anterior cruciate ligament with a tendon graft is the current gold standard. OBJECTIVES: Dynamic intraligamentary stabilization is a new technique for preservation of the anterior cruciate ligament. METHODS: This article describes the indications, operative technique, rehabilitation and preliminary results after dynamic intraligamentary stabilization for acute anterior cruciate ligament ruptures. RESULTS: A total of 24 women and 31 men with an acute anterior cruciate ligament tear were included in a prospective clinical trial. Of the patients 26 had already been followed-up for 12 months and satisfying values for the Lysholm, Tegner and International Knee Documentation Committee (IKDC) outcome scores were achieved. High subjective patient satisfaction was also achieved. The Lachman test showed a mean anterior translation difference to the healthy side of 1.7 mm. CONCLUSION: Dynamic intraligamentary stabilization in combination with microfracturing of the notch can provide biomechanical and biological conditions for self-healing of the anterior cruciate ligament. Further clinical and biomechanical research is needed to identify appropriate patients and rupture types suitable for this new technique.

Comparison of outside-in and inside-out technique for tibial fixation of a soft-tissue graft in ACL reconstruction using the Shim technique.

INTRODUCTION: The aim of this study was to compare the biomechanical properties of tibial fixation of a free tendon graft in ACL reconstruction using the Shim, a new wedge-shaped implant, in an outside-in technique to fixation by the Shim used in an inside-out technique and fixation by interference screw in a porcine model. MATERIALS AND METHODS: Porcine tibia and flexor tendons were used. In Group 1, the Shim was applied outside-in. In Group 2, the Shim was inserted inside-out. In the Group 3, an 8-mm interference screw was used. Ten specimens were tested in each group. Load-to-failure, elongation, stiffness and failure mode were recorded. Cyclic loading was performed between 5 and 250 N for 1,000 cycles, followed by a load to failure testing. RESULTS: Mean maximum load-to-failure was 629.53 N in Group 1,648.54 N in Group 2 and 749.53 N in Group 3. There was no significant difference between the groups. Stiffness varied between 127.34 N/mm in Group 1, 151.27 N/mm in Group 2 and 182.25 N/mm in Group 3. No significant differences were found between outside-in Shim and interference screw fixation. No significant difference was found for elongation among the three groups. The main failure mode was a rupture of the tendon in the IFS group and a slippage of either the implant or the tendon in both groups using the Shim. CONCLUSIONS: As no statistically significant difference could be seen concerning load to failure, stiffness and elongation between the inside-out and the outside-in techniques, the Shim can be used for tibial fixation in an outside-in or inside-out technique depending on the preference of the surgeon. To prevent slippage of the graft a hybrid fixation should be considered.