Položaj implantata kod ekstraartikularnih prijeloma distalnog humerusa – nove hipoteze za liječenje

Through many stages of development, from conservative to operative treatment, open reduction and internal fixation with dual plating systems are the golden standard for fixation of distal humerus fractures. The plates are placed with a slight offset, posteromedially and posterolaterally. In recent publications, a higher stiffness and strength of osteosynthesis in the parallel plating technique were compared to the perpendicular technique with different plate designs. As noted in previous studies, non-union of the distal humerus usually occurs in the region at the metaphyseal and supracondylar level of radial columns due to varus stresses. Therefore the hypothesis is that in the case of extraarticular methphyseal fractures, which are treated with two plates perpendicular or parallel to form, the radial side of the plate should be longer than the ulnar side in order to prevent varus stresses as the main cause of the distal humeral pseudoarthrosis. Sufficient stability can be ensured with newly designed Y-shaped plate which should have a longer radial arm and be configured to prevent varus stresses. To prove this hypothesis, biomechanical studies at the supracondylar metaphyseal level on the border of the distal humerus diaphysis should be performed.U razvojnom procesu od konzervativnog pa do operativnog liječenja prijeloma distalnog humerusa, otvorena repozicija te unutrašnja fiksacija pločicama i vijcima su se pokazale kao najbolja metoda liječenja. Pločice se postavljaju uz blagi pomak posteromedijalno i posterolateralno. U posljednjim biomehaničkim studijama uglavnom je analizirana i uspoređivana krutost i stabilnost osteosinteze s različitim pločicama u paralelnoj i perpendikularnoj konfiguraciji. Dosadašnja istraživanja su također pokazala da su loši rezultati liječenja prijeloma distalnog humerusa uglavnom posljedica neadekvatnog cijeljenja u metafizarnoj i suprakondilarnoj regiji radijalne kolumne zbog varusnih naprezanja. Stoga je hipoteza rada da kod ekstraartikularnih metafizarnih prijeloma koji se liječe s dvije pločice u paralelnoj ili perpendikularnoj konfiguraciji, pločica na radijalnoj strani treba biti dulja od ulnarne kako bi se izbjegla varusna naprezanja koja su u većini slučajeva glavni uzročnik pojave pseudoartroze distalnog humerusa. Dovoljna stabilnost koštanih ulomaka može se osigurati novodizajniranom Y pločicom koja je konfigurirana na način da ima dulji radijalni krak, čime se znatno smanjuju varusna naprezanja. Da bi se navedena hipoteza dokazala, potrebno je provesti biomehanička istraživanja u suprakondilarnoj i metafizarnoj regiji na prijelazu u dijafizarnu regiju distalnog humerusa

Položaj implantata kod ekstraartikularnih prijeloma distalnog humerusa – nove hipoteze za liječenje

Through many stages of development, from conservative to operative treatment, open reduction and internal fixation with dual plating systems are the golden standard for fixation of distal humerus fractures. The plates are placed with a slight offset, posteromedially and posterolaterally. In recent publications, a higher stiffness and strength of osteosynthesis in the parallel plating technique were compared to the perpendicular technique with different plate designs. As noted in previous studies, non-union of the distal humerus usually occurs in the region at the metaphyseal and supracondylar level of radial columns due to varus stresses. Therefore the hypothesis is that in the case of extraarticular methphyseal fractures, which are treated with two plates perpendicular or parallel to form, the radial side of the plate should be longer than the ulnar side in order to prevent varus stresses as the main cause of the distal humeral pseudoarthrosis. Sufficient stability can be ensured with newly designed Y-shaped plate which should have a longer radial arm and be configured to prevent varus stresses. To prove this hypothesis, biomechanical studies at the supracondylar metaphyseal level on the border of the distal humerus diaphysis should be performed.U razvojnom procesu od konzervativnog pa do operativnog liječenja prijeloma distalnog humerusa, otvorena repozicija te unutrašnja fiksacija pločicama i vijcima su se pokazale kao najbolja metoda liječenja. Pločice se postavljaju uz blagi pomak posteromedijalno i posterolateralno. U posljednjim biomehaničkim studijama uglavnom je analizirana i uspoređivana krutost i stabilnost osteosinteze s različitim pločicama u paralelnoj i perpendikularnoj konfiguraciji. Dosadašnja istraživanja su također pokazala da su loši rezultati liječenja prijeloma distalnog humerusa uglavnom posljedica neadekvatnog cijeljenja u metafizarnoj i suprakondilarnoj regiji radijalne kolumne zbog varusnih naprezanja. Stoga je hipoteza rada da kod ekstraartikularnih metafizarnih prijeloma koji se liječe s dvije pločice u paralelnoj ili perpendikularnoj konfiguraciji, pločica na radijalnoj strani treba biti dulja od ulnarne kako bi se izbjegla varusna naprezanja koja su u većini slučajeva glavni uzročnik pojave pseudoartroze distalnog humerusa. Dovoljna stabilnost koštanih ulomaka može se osigurati novodizajniranom Y pločicom koja je konfigurirana na način da ima dulji radijalni krak, čime se znatno smanjuju varusna naprezanja. Da bi se navedena hipoteza dokazala, potrebno je provesti biomehanička istraživanja u suprakondilarnoj i metafizarnoj regiji na prijelazu u dijafizarnu regiju distalnog humerusa

Evaluation of functional outcome after osteosynthesis of intra articular distal humerus fracture with pre contoured locking compression plates

Background: Intra articular distal humerus fractures are challenging and cumbersome to treat. Therefore osteosynthesis of such fractures is required. The aim of our study was to evaluate the functional outcome of intra articular distal humerus fractures AO type  13C by osteosynthesis using olecranon osteotomy with pre contoured locking compression plates in orthogonal plate configuration.Methods: Thirty patients were included in our study comprising of 18 males and 12 females. Mean age was 39.63 years with mean follow up of 34 weeks. 7 were AO type 13C1, 9 were AO type 13C2 and 14 were AO type 13C3. Osteosynthesis was done for all fractures by olecranon osteotomy approach. Functional outcome was assessed using mayo elbow performance score.Results: Mean flexion attained at the end of follow up was 127.56 degrees with mean extensor lag of 7.16 degrees. Mean arc of motion was 120.4 degrees. Mean mayo elbow performance score at the end of follow up was 80.36. Mayo elbow performance score in patients aged less than 40 years of age was not statistically significant as compared to patients more than 40 years of age. Functional outcome was also dependent on fracture subtype.Conclusions: Osteosynthesis of distal humerus fractures AO type 13C using pre contoured locking compression plates in orthogonal plate configuration by olecranon osteotomy provides excellent visualization of fracture and better functional outcome

Treatment of distal humeral fractures using conventional implants. Biomechanical evaluation of a new implant configuration

<p>Abstract</p> <p>Background</p> <p>In the face of costly fixation hardware with varying performance for treatment of distal humeral fractures, a novel technique (U-Frame) is proposed using conventional implants in a 180° plate arrangement. In this in-vitro study the biomechanical stability of this method was compared with the established technique which utilizes angular stable locking compression plates (LCP) in a 90° configuration.</p> <p>Methods</p> <p>An unstable distal 3-part fracture (AO 13-C2.3) was created in eight pairs of human cadaveric humeri. All bone pairs were operated with either the "Frame" technique, where two parallel plates are distally interconnected, or with the LCP technique. The specimens were cyclically loaded in simulated flexion and extension of the arm until failure of the construct occurred. Motion of all fragments was tracked by means of optical motion capturing. Construct stiffness and cycles to failure were identified for all specimens.</p> <p>Results</p> <p>Compared to the LCP constructs, the "Frame" technique revealed significant higher construct stiffness in extension of the arm (P = 0.01). The stiffness in flexion was not significantly different (P = 0.16). Number of cycles to failure was found significantly larger for the "Frame" technique (P = 0.01).</p> <p>Conclusions</p> <p>In an in-vitro context the proposed method offers enhanced biomechanical stability and at the same time significantly reduces implant costs.</p

Behandlingsmetoder för frakturer på långa rörformiga ben hos häst : en jämförelse mellan svenska och utländska erfarenheter

The treatment of long bone fractures in horses remains to be a challenge for equine veterinarians, since it is necessary to succeed treating an animal sometimes weighing over 500kg that will have to endure fracture repair procedures and rehabilitation for at least 3 months and manage the resulting complications. The objective of this study is to investigate and shed light over some of the treatment techniques for long bone fractures in equines, and to sample new data from a questionnaire, answered by experienced equine surgeons in Sweden, summarising the obtained results with the already existing research. In a literature review, this work starts by describing bone anatomy and physiology, gradually narrowing down to long bones. Then the different types of bone fractures are discussed, both in regards to their aetiology, impact and classification. This is followed by the mechanisms of bone healing through which bone fractures are healed. Further, this work investigates the most common and current treatment techniques of long bone fractures in equines. Various treatment techniques are reviewed, such as the internal and the external fixation, as well as the advantages and the disadvantages of every respective technique. Furthermore, the factors that affect long bone fracture repair are described, as well as the biomechanics of the strain forces that need to be counteracted for successful fracture treatment. Finally, the literature study describes the various complications that may follow bone fracture repair post-operatively or during the rehabilitation phase. In addition, the study encompasses a questionnaire that was sent to 20 Swedish senior equine surgeons, asking questions about long bone fracture treatment. Some of them replied to the questionnaire, elucidating on how the different types of long bone fractures are dealt with in Sweden, thus helping the study to exhibit the current practices of equine orthopaedic surgery, as they are adapted to the Swedish realities, including the animal welfare norms. The results of the survey showed that veterinarians who heavily rely on surgical treatment do tend to have a lesser need to resort to euthanasia, than other veterinarians, who do not apply osteosynthesis as their primary treatment. Moreover, there seems to be a general correlation between the orthopaedic practices applied by equine surgeons in Sweden and the ones described in foreign literature, with the distinction that the Swedish veterinary policy applies conservative treatment as standard, unless the fracture is displaced.Behandling av frakturer på långa rörformiga ben hos häst är en utmaning för hästveterinärer. Det är svårt att behandla ett i grunden flocklevande flyktdjur, som kan väga över 500 kg, för skador som måste läka i minst 3 månader. Därtill kan man behöva hantera resulterande komplikationer. Syftet med denna studie var att undersöka och belysa några av de behandlingstekniker som används för frakturer på långa rörformiga ben hos häst. Dessutom, via en enkät besvarad av erfarna hästkirurger som arbetar i Sverige, få en uppfattning om hur dylika frakturer vanligen behandlas i detta land. I litteraturöversikten beskrivs benanatomi och fysiologi med fokus på hästens långa rörformiga ben. Olika typerna av benfrakturer tas upp avseende sin etiologi, inverkan och klassificering följt av frakturläkningens grunder. Behandlingstekniker såsom intern och extern fixeringen, samt fördelar och nackdelar med varje teknik gås igenom översiktligt. Vidare tas faktorer som påverkar reparation av frakturer på långa rörformiga ben upp inklusive de biomekaniska krafter som behöver motverkas för en framgångsrik frakturbehandling. Även olika komplikationer som kan uppstå perioperativt och under rehabiliteringsfasen berörs. Det frågeformulär som skickades till 20 erfarna hästkirurger i Sverige med frågor om behandling av frakturer på långa rörformiga ben hos häst besvarades av 9 personer som alla hade över 20 års erfarenhet av hästkirurgi. De redogjorde för hur de hanterat olika typer av frakturer i hästens långa rörben. Även djurskyddsaspekter förknippade med fraktur hos häst berördes. Resultaten visade att veterinärer som arbetar på klinik och lutar sig mot kirurgisk behandling i sin praktik troligen har ett mindre behov av att avliva patienter än veterinärer som inte har möjlighet använda osteosyntes i sin behandling. Det fanns en överensstämmelse mellan de ortopediska metoder som tillämpas av hästkirurger i Sverige och de som beskrivs i utländsk litteratur. Dock med skillnaden att svenska hästkiruger oftast tillämpar konservativ behandling, ofta i hängmatta, som standard då frakturen inte är öppen, dislocerad och/eller instabil

Biomechanical Evaluation of Two Methods of Humeral Shaft Fixation

Biomechanical evaluations of fracture fixation devices attempt to determine implant performance by approximating the in vivo conditions. This performance is affected by many factors and relies on the complex bone-implant interface. Biomechanical tests can be designed in a variety of ways in order to evaluate device performance with respect to any number of these bone-implant interactions. Standardized tests, designed by groups such as the American Society for Testing and Materials (ASTM), are often designed either to determine the performance of a specific type of fixation device or for direct comparison between different devices. Additionally, many biomechanical evaluations are designed for direct comparison between the devices being evaluated. Often times these tests utilize bone analogs in order to eliminate variability. Finally, the method and location of load application greatly influences device performance outcomes. Cyclic tests determine fatigue performance whereas quasi-static tests are used to define device limits (i.e. - Young\u27s modulus, and ultimate/yield properties). Physiologically equivalent loading patterns expose fixation devices to combined loading modalities most closely resembling the in vivo conditions. This paper will explore the variety of ways in which biomechanical testing of fracture fixation devices are performed. Specific focus will be given to the design and application of biomechanical tests which simulate physiologically relevant loading. Physiologically relevant/equivalent loading refers to the simulation of in vivo loads with respect to anatomic alignment. This examination will include details regarding the differences in biomechanical test designs between weight-bearing (i.e. - lower limb) and non-weight-bearing (i.e. - upper limb) fixation devices. These concepts will then be put to use for the purpose of evaluating the biomechanical performance of two methods of humeral shaft fixation. The results of this study have been submitted for publication in the Journal of Surgical Orthopaedic Advances