Sonographische Darstellung und Lokalisation von Metallimplantaten

In a first experimental study we investigated the visualisation of metal implants in reference to dimension, shape, material (titanium, steel, biodegradable screws) and surface structures and an eventual change of the echo pattern in correlation to the surrounding structures, the vicinity to bone and the change of the sound angle. For this purpose ultrasound investigation was performed in artificial and cadaver bones and in cadaver limbs after implantation of screws, plates, K-wires and cerclage wires. We found that metal implants of a certain dimension can be localised by typical artefacts (resonance artefact, comet tile artefact). In the following clinical study we investigated the value of ultrasound in finding and localisation of implants after osteosynthesis. In patients with 25 locking femur nailing, 30 locking tibia nailing, 30 osteosynthesis done by screws and plating, metal was easily localised by typical artefacts. Ultrasound examination gave the possibility to define the number of screws, the localisation to surrounding tissue, loosening of screws and eventual as sociated inflammatory tissue swelling (bursitis, tendovaginitis).     

Mono- vs. polyaxiale winkelstabile Plattensysteme

Conventional plate osteosynthesis is undergoing a period of transition. The concept of locking plate osteosynthesis is of special importance. Monoaxial locking plate osteosynthesis has shown promising results (rapid bone healing via callus, minimal soft tissue irritation, advantageous in osteoporosis). Some implants allow for polyaxial locking. The first results of comparative studies concerning biomechanics and clinical outcome of mono- versus polyaxial locking plates are presented.     

Die Versorgung der distalen Radiusfraktur

Background

How effective is open reduction and internal fixation with palmar locking plates compared to closed reduction and internal fixation with K-wires in the treatment of fractures of the distal radius?

Method and materials

A systematic review of the literature was performed for the years 2002 to 2012 to find controlled studies comparing K-wires and locking palmar plates. Follow-up, complications, functional results, radiographic results and peculiarities of the studies were analyzed.

Results

A total of five controlled studies could be found and additionally the data of one unpublished controlled prospective study were added. In two studies a better function (DASH) could be achieved following palmar locking plate osteosynthesis, in one study better results were found following K-wire osteosynthesis and three studies found no significant differences. Ulna variation was found to be better restored following palmar locking plate osteosynthesis in two, palmar inclination in two and radioulnar inclination in one study. There were 7.3% complications following palmar locking plate osteosynthesis compared to 20% following K-wire fixation; however, the complications following plate osteosynthesis were more severe.

Conclusions

Palmar locking plates as well as K-wire fixation are suitable techniques for the treatment of fractures of the distal radius. The higher stability of locking plates seems to lead to an earlier functional recovery but this possible advantage disappears in the long-term follow-up.     

Gibt es noch eine Differenzialindikation für die Behandlung der distalen Radiusfraktur?

The therapeutic strategy for fractures of the distal radius can now be defined. The degree of instability and pattern of injury determine whether treatment should be nonoperative or operative. Advanced age and osteoporosis are no longer contraindications for surgery. In general plating with a locking plate can be regarded as the standard procedure. When it is used for internal fixation it gives the best biomechanical stability. Autologous bone grafting is not usually necessary, and the fixed angle means that postoperative functional therapy is possible. There are systems with limited polyaxial screw direction (multidirectionality). When locking plates are used the surgical approach can be selected by recourse to an appropriate algorithm. For most indications the volar approach is preferable. Nevertheless, there are also arguments in favour of the dorsal approach, especially in the case of revision surgery for dorsally angulated malunions. Complications mostly affect the soft tissues, and their frequency is comparable for the dorsal and volar approaches. Alternative methods of osteosynthesis should be restricted to specific situations. In our series osteosynthesis was predominantly performed with the locking plate (80%) and mainly by the volar approach (69%). Alternative methods of osteosynthesis were applied in only 20% of our cases.     

Minimally Invasive Anterior Plate Osteosynthesis in Humeral Shaft Fractures

Abstract   Twelve patients with shaft fractures of the humerus were treated with percutaneous anterior plate osteosynthesis using a deltoid-pectoral respectively brachialis splitting approach without exposure of the radial nerve. The implants used were PHILOS plates, locking compression plates 3.5 and 4.5, and a tibial metaphyseal plate (all by Synthes). There were no intraoperative complications, no infections and no iatrogenic injuries of the radial or axillary nerve. Nine fractures healed entirely. There was one pseudarthrosis caused by a plate that was too short; another fracture probably healed but the distal screws broke; and one patient was lost to follow-up. Minimally invasive anterior plate osteosynthesis in humeral shaft fractures is an operative alternative which may be indicated not only in delayed healing or complex shaft fractures.     

Akute Frakturversorgung mit Kompressionsmarknagel

Intramedullary compression nailing leads to very stable osteosynthesis of AO type A2 and A3 fractures of long bones. Both antegrade and retrograde approaches are possible in the case of fractures of humerus, tibia and femur. If a telescoping effect is observed during the operation the dynamic procedure can be changed for a static one when these implants are used. When this technique is applied in polytrauma and soft tissue damage the principles are the same as for other techniques using locking medullary nails. The advantages of the compression nailing technique are the very high stability for torsion and the continuous compression of the fracture even without weightbearing. We have not observed any disadvantages arising from reaming of the marrow cavity.     

Fracture of the tibial head]

Fractures of the tibial head are marked by huge variety. They can be classified into fractures of the tibial plateau, luxation fractures, and comminuted fractures. Luxation fractures are commonly associated with lesions of the menisci and intra- and extra-articular ligaments. Several factors may be responsible for the development of post-traumatic OA: anatomically nonreduced joint surface, malalignment, and unaddressed associated injuries. Therefore a sophisticated therapeutic regime is necessary. In case of severely damaged soft tissue or unstable patients, the fracture should first be reduced and fixed with an external fixateur and the osteosynthesis should be performed in a second setting. Arthroscopically assisted reduction and osteosynthesis are indicated for fractures of the tibial eminence, crack fractures, and impression fractures. Comminuted fractures can be addressed via several different incisions. Due to locking plates, the bilateral use of large plates can be avoided. In specific cases such as compound fractures and for patients with low compliance, hybrid fixateurs may be an alternative.     

Tibiakopffraktur

Fractures of the tibial head are marked by huge variety. They can be classified into fractures of the tibial plateau, luxation fractures, and comminuted fractures. Luxation fractures are commonly associated with lesions of the menisci and intra- and extra-articular ligaments. Several factors may be responsible for the development of post-traumatic OA: anatomically nonreduced joint surface, malalignment, and unaddressed associated injuries. Therefore a sophisticated therapeutic regime is necessary. In case of severely damaged soft tissue or unstable patients, the fracture should first be reduced and fixed with an external fixateur and the osteosynthesis should be performed in a second setting. Arthroscopically assisted reduction and osteosynthesis are indicated for fractures of the tibial eminence, crack fractures, and impression fractures. Comminuted fractures can be addressed via several different incisions. Due to locking plates, the bilateral use of large plates can be avoided. In specific cases such as compound fractures and for patients with low compliance, hybrid fixateurs may be an alternative.     

From unstable internal fixation to biological osteosynthesis. A historical overview of operative fracture treatment

The first techniques of operative fracture treatment were developed in the 19th century. In fact, these methods only consisted of an open reduction of the fracture followed by a usually very unstable fixation. This method gave rise to the combination of the disadvantages of the conservative and the operative fracture treatment: the fracture had to be opened with a real risk for (sometimes lethal) infection, the bone healing was disturbed, there was muscular atrophy and joint stiffness. The successes were very rare and catastrophes were often seen. Küntscher's endomedullary rods can be considered as the first useful implants in the treatment of diaphyseal fractures. Reaming of the medullary canal and the development of interlocking nails have enlarged the indications for intramedullary nailing. The classic Dynamic Compression Plates from the seventies were the key to a very rigid fixation, leading to primary bone healing. Nevertheless, the use of strong plates and reamed nails disturbed the vascularisation of the bone fragments, leading to a high infection rate (particularly in open fractures) and delayed union (particularly after plate and screw fixation). These insights lead to the development of the "biological osteosynthesis" : a terminology introduced to indicate a new type of osteosynthesis leading to a sufficiently stable fixation of the bone fragments allowing early mobilisation, but without major disturbance of the vascularisation. The unreamed nail can also be considered as a biological osteosynthesis and in a lot of cases it is the implant of choice for tibial and femoral shaft fractures, especially in polytrauma patients. Finally, some new devices contributing to the principles of biological osteosynthesis like locking plates and the LIS-System are gaining popularity.     

Experience in the use of AO-Poldy implants for supraosseus osteosynthesis

Having used since 1968 in MONICI the massive metal plates of different configuration and size, developed by Swiss association of osteosynthesis AO and Czechoslovakian company Poldy, the authors summarize the experience of great clinical material. Altogether, there have been operated over 1000 patients with recent and inveterate fractures of tubular bones, pseudoarthroses, incorrectly consolidated fractured fragments, and 603 of them in MONICI. Some of the implants have been adapted by the authors. In doing so, AO principles and techniques were thoroughly observed. Positive results obtained at 96% of patients with grave bone pathology demonstrate expediency of more broad introduction of the mentioned implants for supraosseous osteosynthesis in our country.     

Principles and clinical application of the locking compression plate (LCP)

The principle of the locking compression plate (LCP) is represented by the combination of two completely different anchorage technologies and two opposed principles of osteosynthesis in one implant it combines the principles of conventional plate osteosynthesis for direct anatomical reduction with those of bridging plate osteosynthesis. Since the LCP can be used as a conventional plate using only dynamic compression, as a pure internal fixator using locking head screws, or as both combined, it provides the surgeon with multiple variations. Nevertheless, these new possibilities mean that preoperative planning and an understanding of the different biomechanical principles of osteosynthesis are essential if good clinical outcomes are to be achieved and maximum benefit is to be attained from the options offered by the LCP system. The current article provides biomechanical background to and guidelines for the use of LC plates in the operative treatment of fractures and also reports experimental and clinical results obtained with LCP.     

Treatment of radial head and neck fractures: in favor of anatomical reconstruction

Radial head fractures represent the most common elbow fractures. Undisplaced fractures usually occur in isolation and can be treated nonsurgically. Displaced fractures should be treated surgically. Simple two-part fractures can easily be handled by osteosynthesis, but comminuted fractures pose a major problem for reconstruction. As the radial head is an important stabilizer of the elbow joint??especially in the context of concomitant ligamentous injuries??its resection may lead to pain, limited range of motion, and instability. Therefore, radial head resection is not recommended for the acute situation and open reduction internal fixation (ORIF) or prosthetic replacement should be aimed for. Complications such as secondary loss of fixation, radial head necrosis, and nonunion due to insufficient stability of the osteosynthesis have often been described. Therefore, prosthetic replacement is recommended if stable reconstruction is impossible. With the development of new locking plates especially designed for the maintenance of radial head fractures, the indications for osteosynthesis may be extended. As radial head fractures are complicated by a high percentage of ligamentous injuries and concomitant elbow fractures such as the coronoid, capitellum, and proximal ulna, these additional injuries have to be taken into account. The current treatment concepts are discussed within this paper.     

Diaphysäre Humeruspseudarthrosen

The development of humerus nonunion is dependent on the type of fracture, the extent of soft tissue stripping during surgery, the stability of the osteosynthesis, and multiple patient-dependent factors. Treatment should focus on nonunion pathogenesis. The gold standard for the treatment of oligotrophic, atrophic and infected nonunions is radical resection of the nonunion tissue, bone grafting and plate fixation, preferentially using locking plates. Reaming bone graft and stabilization with intramedullary (i.m.) nailing is utilized in hypertrophic nonunion. Since 1993, we have followed-up 51 patients after surgical treatment for humeral shaft nonunion. In eight of 35 cases (22.8%) treated with i.m. nailing, bone healing was not achieved, whereas in all 14 cases of nonunion treated with plate osteosynthesis bone healing occurred. Evaluation of failure in healing humeral shaft nonunion using the i.m. nailing technique revealed that the i.m. nail specifically designed to treat humeral shaft fractures showed several biomechanical and biological deficits for the treatment of nonunions. The major reason for failure in bone healing was a lack of bone grafting that is essential for osteoinduction in oligotrophic nonunions, loosening of locking screws, and unstable small implants.     

Locked plating in orthopaedic trauma: a clinical update

Locked plating for fracture fixation has enjoyed widespread popularity despite a paucity of published data on outcomes. Anatomically precontoured locked plates that allow fixation in various anatomic regions are widely available. New technologies incorporate subchondral support locking pegs, polyaxial bushings, and locking washers to improve intraoperative versatility. However, limited data are available on the efficacy of these new implants. The clinical performance of locked plates generally has been good. However, several unique complications have been noted, such as difficulty with implant removal, malalignment, fracture distraction, and loss of diaphyseal fixation, especially with percutaneous techniques and unicortical screws. The expense of locked plate constructs is a concern. This technology typically costs three times more than similar unlocked constructs. Locked constructs should be reserved for problematic fractures that have demonstrated poor outcomes with unlocked constructs.     

Flexible fixation and fracture healing: do locked plating 'internal fixators' resemble external fixators?

External and internal fixators use bone screws that are locked to a plate or bar to prevent periosteal compression and associated impairment of blood supply. Both osteosynthesis techniques rely on secondary bone healing with callus formation with the exception of compression plating of simple, noncomminuted fractures. External fixation uses external bars for stabilization, whereas internal fixation is realized by subcutaneous placement of locking plates. Both of these "biologic" osteosynthesis methods allow a minimally invasive approach and do not compromise fracture hematoma and periosteal blood supply. Despite these similarities, differences between the two fixation methods prevail. Locked plating "internal fixators" allow a combination of biomechanical principles such as buttressing and dynamic compression. Periarticular locking plates are anatomically contoured to facilitate fixation of articular fractures. They allow for subchondral stabilization using small-diameter angular stable screws as well as buttressing of the joint and the metaphyseal component of a fracture. Biomechanically, they can be far stiffer than external fixators, because subcutaneous plates are located much closer to the bone surface than external fixator bars. External fixators have the advantage of being less expensive, highly flexible, and technically less demanding. They remain an integral part of orthopaedic surgery for emergent stabilization, for pediatric fractures, for definitive osteosynthesis in certain indications such as distal radius fractures, and for callus distraction.     

Sekundäre Endoprothetik des Ellenbogengelenks nach distaler Humerusfraktur

Good short-term results have been reported for primary total elbow arthroplasty (TEA) but implant longevity is limited. Therefore, primary TEA should be reserved in particular for older patients with severe comminuted distal humeral fractures in whom successful osteosynthesis is often impossible. Angular locking compression plates afford stable fracture fixation even for a severe intra-articular fracture pattern. To date primary TEA for treatment of severe distal humeral fractures is rarely used. Secondary TEA is used in failed osteosynthesis of distal humeral fractures and in unstable post-traumatic elbow joints with osteoarthrosis. Additionally, secondary TEA has become more popular in younger patients for immediate pain reduction and functional improvement. However, weight bearing is limited to 5 kg, racket sports are prohibited and good patient compliance is mandatory. Long-term results of TEA are poorer for trauma patients than those with rheumatoid arthritis.     

Interindividual anatomical variations affect the plate‐to‐bone fit during osteosynthesis of distal radius fractures

We hypothesized that interindividual variations in the teardrop, which represents the volar projection of the lunate facet of the distal radius, cause unsatisfactory fitting of the volar locking plate to the bone. This can cause flexor tendon ruptures. Herein, we conducted a cross‐sectional study and measured the ratio of teardrop height and the teardrop inclination angle as parameters of teardrop configuration for 200 standardized lateral radiographs (average age of the patients, 51 years). We also quantified the influence of the teardrop morphology by analyzing the fit of three locking plates to three radii with differing teardrop inclination angles using a three‐dimensional computer‐aided design system. The average ratios of the teardrop height and teardrop inclination angle were 0.42° (0.30–0.56°) and 28.8° (9.9–44.9°), respectively. The teardrop inclination angle was moderately correlated with age in men but not in women. In the plate‐to‐bone fit analyses, the fit of all the plates was significantly different between bones, with the configuration of the radius with the lowest teardrop inclination angle being the closest approximation to that of each plate. We demonstrated the interindividual variation in the shape of the teardrop and its influence on the fit of the volar plate, highlighting the importance of careful plate selection for achieving osteosynthesis of bones with a high teardrop inclination angle. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:953–960, 2016.     

Implantatassoziierte Frakturen

Only scant information is currently available on the treatment of implant-related and periprosthetic fractures of the humerus. Although the incidence of these fractures is low, an increase is expected in the future. Treatment is challenging since patients are often elderly and bone quality is poor. Conservative treatment often leads to delayed healing and non-union. Treatment goals include reliable implant fixation, sufficient stability to enable bony healing and stable osseointegration of the prosthesis for pain-free and useful joint function. Whereas long-stem revision surgery is performed in cases of loose stems and poor bone quality, overlapping osteosynthesis with angle stable plating systems and cerclages can be used in cases of good bone quality. With implant-related fractures at the junction between rigid bone due to an implant and flexible bone, revision surgery using long angle-stable plates or overlapping plates additional to the remaining implants can be accomplished. New intramedullary implants (long proximal humerus nails) can be successfully used either in primary osteosynthesis or in cases of revision and can achieve sufficient stability for early functional aftercare.     

Biomechanical investigation of an alternative concept to angular stable plating using conventional fixation hardware

Background  

Angle-stable locking plates have improved the surgical management of fractures. However, locking implants are costly and removal can be difficult. The aim of this in vitro study was to evaluate the biomechanical performance of a newly proposed crossed-screw concept ("Fence") utilizing conventional (non-locked) implants in comparison to conventional LC-DCP (limited contact dynamic compression plate) and LCP (locking compression plate) stabilization, in a human cadaveric diaphyseal gap model.     

Small animal bone healing models: standards, tips, and pitfalls results of a consensus meeting

Small animal fracture models have gained increasing interest in fracture healing studies. To achieve standardized and defined study conditions, various variables must be carefully controlled when designing fracture healing experiments in mice or rats. The strain, age and sex of the animals may influence the process of fracture healing. Furthermore, the choice of the fracture fixation technique depends on the questions addressed, whereby intra- and extramedullary implants as well as open and closed surgical approaches may be considered. During the last few years, a variety of different, highly sophisticated implants for fracture fixation in small animals have been developed. Rigid fixation with locking plates or external fixators results in predominantly intramembranous healing in both mice and rats. Locking plates, external fixators, intramedullary screws, the locking nail and the pin-clip device allow different degrees of stability resulting in various amounts of endochondral and intramembranous healing. The use of common pins that do not provide rotational and axial stability during fracture stabilization should be discouraged in the future. Analyses should include at least biomechanical and histological evaluations, even if the focus of the study is directed towards the elucidation of molecular mechanisms of fracture healing using the largely available spectrum of antibodies and gene-targeted animals to study molecular mechanisms of fracture healing. This review discusses distinct requirements for the experimental setups as well as the advantages and pitfalls of the different fixation techniques in rats and mice.