Abstract There are previous reports of an increasing incidence of children’s forearm fractures in the last few decades. Their surgical treatment is evolving. The present study was aimed at determining the incidence and background of these fractures and their treatment. It was also aimed to analyse the short- and long-term outcomes. A comprehensive population-based study (N=168) among 86,000 children in Oulu University Hospital District over a decade (2000–2009) was performed to analyse the incidence of middle-third forearm fractures. Further data (N=291) covering 1997–2009 was achieved in order to study monthly variation and backgrounds of all both-bone forearm fractures in the distal, middle or proximal thirds. An age- and sex-matched case-control study (N=94) at Vaasa Central Hospital District in 1995–1999 with approximately 11 years of follow-up was performed to evaluate long-term morbidity. The relationship between summer weather and outdoor fractures was based on daily weather readings of all summer days (N=1989) in 1997–2009. There was a 4.4-fold increase in middle-third shaft fractures in the last decade (2000–2009) and a 3.1-fold increase in all forearm shaft fractures (proximal, middle and distal) in 1997–2009. The increase in the middle-shaft fractures was still accelerating towards the end of the study period. Trampolining was increasing as a reason for the injuries. At the end of the study every third fracture was caused by a trampoline injury. The fractures caused by other recreational activities increased absolutely, but they were stable in relation to trampoline injuries. There was a clear monthly variation in fracture incidence. During the long study time, August was repeatedly the most usual month for the fractures. School terms and summer holidays did not explain the varying fracture risk. The incidence of the fractures was 50% higher in dry vs. rainy days in summer. Temperature and wind speed did not affect fracture risk. Not only were the number of children’s forearm shaft fractures increasing, but also their operative treatment in 1997–2009. The increase was mostly connected to elastic stable intramedullary nailing (ESIN), the incidence of which changed from 10% to 30% during the study period, compared with other types of treatment. Non-operative treatment showed poor short-term outcome in the form of worsening alignment and a relatively great need of re-operations. Operative treatment showed excellent primary results. In the long run, the outcome of non-operative treatment was excellent. / Tiivistelmä Lasten kyynärvarren diafyysimurtumat ovat lisääntyneet viimeisten vuosikymmenten aikana. Samalla niiden kirurginen hoito on muuttunut. Tämän tutkimuksen tavoitteena oli selvittää murtumien ilmaantuvuutta ja murtumien taustalla olevia tekijöitä sekä hoidon kehittymistä. Tavoitteena oli myös tutkia lyhyt- ja pitkäaikaisia hoitotuloksia. Ilmaantuvuuden määrittämiseksi kerättiin väestöpohjainen aineisto (N=168) kaikista niistä lapsista (<16-v.), jotka ovat olleet hoidossa Oulun yliopistollisessa sairaalassa kyynärvarren keskialueen murtuman vuoksi 2000–2009. Taustatekijöiden selvittämiseksi aineisto laajennettiin koskemaan kaikkia kyynärvarren kahden luun murtumia (proksimaaliset, keskialueen ja distaaliset murtumat) 1997–2009 (N=291). Pitkäaikaistuloksia arvioitiin tapaus-verrokkitutkimuksella (N=94), jonka potilasaineiston muodostivat Vaasan keskussairaalassa vuosina 1995–1999 hoidetut lapsipotilaat. Ikä- ja sukupuolivakioidut vertailutapaukset poimittiin väestörekisteristä. Kesäsään ja ulkona tapahtuvien murtumien välisen yhteyden tutkimiseksi kerättiin säätila-aineisto kaikilta vuosien 1997–2009 kesäpäiviltä (N=1989). Lasten kyynärvarren keskidiafyysin murtumat lisääntyivät 4,4-kertaisesti vuosikymmenessä (2000–2009) ja kaikki diafyysimurtumat lisääntyivät 3,1-kertaisesti (1997–2009). Keskidiafyysimurtumien ilmaantuvuus kasvoi kiihtyvästi. Trampoliini aiheutti yksinään joka kolmannen murtuman, ja trampoliinimurtumien ilmaantuvuus kasvoi tutkimusaikana. Muut tapaturmatyypit pysyivät vakioisina. Murtumien ilmaantuvuus vaihteli kuukausittain, mutta 13 vuoden seurantajaksolla ne olivat selvästi yleisimpiä elokuussa. Koululaisten kesäloma ei vaikuttanut murtumariskiin. Murtumat olivat 50 % yleisempiä kuivalla säällä kuin sadesäällä. Lämpötila tai tuulennopeus eivät vaikuttaneet murtumien ilmaantuvuuteen. Lasten kyynärvarsimurtumien operatiivinen hoito lisääntyi. Joustavien ydinnaulojen käyttö kasvoi 10 %:sta 30 %:iin suhteessa muihin hoitomuotoihin. Kajoavan hoidon lyhytaikaiset tulokset olivat erinomaiset. Kajoamattoman hoidon tulokset olivat heikot, ja hoitoon liittyi paljon asennon huonontumista ja myöhempää leikkaustarvetta, erityisesti asennon korjaamista. Pitkän ajan seurannassa kajoamattoman hoidon tulokset olivat kuitenkin erinomaiset. / Sammanfattning Barns underarmsfrakturer har ökat under de senaste årtiondena och deras behandling är under förändring. Syftet med den här forskningen var att undersöka underarmsfrakturer: förekommande, bakgrund och behandling. Meningen var också att bedöma resultat av olika frakturbehandlingar på kort och lång sikt. Totalt 168 barn undersöktes. De behandlades på Uleåborgs universitetssjukhus åren 2000–2009 p.g.a. en underarmsfraktur i mellersta tredjedelen av skaft. Därtill inkluderades 291 barn med en underarmsfraktur i hela skaftet åren 1997–2009. En fall-kontroll–undersökning innehöll 47 barn med en underarmsfraktur i Vasa centralsjukhus åren 1996–1999 samt en köns- och ålders standardiserad kontroll grupp med 47 medlemmar (N=47). Relationen mellan sommarväderlek och frakturer som skedde utomhus analyserades på basis av uppgifter om väderleken på alla sommardagarna åren 1997–2009 (N=1989). Frakturer i den mellersta underarmen ökade 4,4-faldigt och accelererande på ett årtionde (2000–2009) och alla skaftfrakturer 3,1-faldigt (1997–2009). Trampolinen tillfogade var tredje av dessa frakturer och således ökade trampolinens betydelse. Jämfört med trampolinen höll sig andra bakgrundsfaktorer stadiga. Det fanns en klar variation i förekommande av frakturer mellan månaderna. Mest förekom frakturer i augusti. Skolperioden eller sommarlovet påverkade inte risken för frakturer. Uppehållsväder ökade risken 1,5-faldigt jämfört med regniga dagar. Temperaturen eller vinden hade ingen effekt på frakturer. Operativa kirurgiska behandlingar ökade i stället för ej-operativa behandlingar åren 1997–2009. Ökningen berodde mest på tilltagande bruk av flexibla märgspikar, vilket ökade från 10 % till 30 % jämfört med andra behandlingsmetoder. Ej-operativ vård visade gott om komplikationer under den korta uppföljningen. Operativ vård var framgångsrik på kort sikt. Däremot visade ej-operativ behandling utmärkta resultat efter den långa uppföljningen.

In der vorliegenden tierexperimentellen Studie wurde die Frakturheilung an der diaphysären Schafstibia mit dem Fixateur intern zur Plattenosteosynthese und zur unaufgebohrten Marknagelung verglichen. Zu diesem Zweck wurde ein neues, geschlossenes Frakturmodell mit Weichteilschaden entwickelt und in einer ersten Versuchsreihe validiert. In den anschließenden beiden Hauptversuchen erfolgte der direkte Vergleich des Fixateur intern zu beiden anderen Stabilisierungsverfahren. Zur Beurteilung der Frakturheilungen wurden radiologische, histologische und biomechanische Messungen, sowie in vivo Belastungsmessungen beider Hinterläufe der Schafe durchgeführt. Im Vergleich zur Plattenosteosynthese ergab sich eine schnellere Frakturheilung nach Fixateur intern Stabilisierung. Diese Vorteile zeigten sich nach 12 Wochen mit signifikanten Unterschieden in den biomechanischen und histologischen Resultaten. Durch die Beinbelastungsmessungen konnte ausgeschlossen werden, daß diese Ergebnisse auf mögliche Unterschiede in dem Belastungsverhalten der Tiere und somit auf unterschiedliche mechanische Kallusstimulation zurückzuführen sind. Im Vergleich zur Marknagelung wurden keine signifikanten Unterschiede in den biomechanischen Messungen festgestellt. In der histologischen Auswertung fand sich zu beiden Zeiträumen eine gleiche Kallusmenge mit vergleichbaren mineralisierten Anteilen. Unterschiede zeigten sich nur in dem Verhältnis endostaler zu periostaler Kallusbildung. Diese Ergebnisse wurden mit den ersten klinischen Resultaten von zwei multizentrischer Studien zur Anwendung von Fixateur intern Systemen in Verbindung gesetzt. Den experimentellen und klinischen Ergebnissen zu Folge, ist der Fixateur intern aus biologischer und biomechanischer Sicht der Plattenosteosynthese überlegen, und stellt zur Marknagelung - insbesondere im metaphysären Bereich - eine sichere Alternative. / In the presented study fracture healing of the sheep tibia treated with an internal fixator were compared to conventional plate osteosynthesis and intramedullary nailing. For that reason a new fracture model with a reproducible closed soft tissue damage were developed and validated in a pilot study on the sheep tibia. In both main experiments a direct comparision of the internal fixator were preformed to one of the other stabilization options. Fracture healing were ranked by radiological, histological and biomechanical data, as well as in vivo measurements of both hind legs of the sheep. In comparison to conventional plating a more rapid healing of the fracture were observed after internal fixator stabilization. Those differences were significant for the biomechanical as well as the histological data after 12 weeks. However, in comparision to intramedullary unreamed nailing no significant differences were detected in respect to biomechanical stiffness and strength. In the histological measurements a similar amount of the overall callus with a similar grade of bone mineralisation were present after 6 as well as after 12 weeks. Only the relation between endostal and periostal callus differed between the internal fixator and the nailing group. Those experimental results were correlated with the first clinical results of two multicenter studies using the new internal fixator systems. Based on the experimental and the clinical results, the internal fixator is superior compared to conventional plate osteosynthesis in respect to the biology and biomechanics, and seems to be a safe alternative - especial in the metaphysis area - to intramedullary nailing.

<div>Delayed fracture healing is a major health issue involved with aging. Therefore, strategies to improve the pace of repair and prevent non-union are needed in order to improve patient outcomes and lower healthcare costs. In order to accelerate bone fracture healing noninvasively, we sought to develop a drug delivery system that could safely and effectively be used to deliver therapeutics to the site of a bone fracture. We elected to pursue the promising strategy of using small-molecule drug conjugates that deliver therapeutics to bone in an attempt to increase the efficacy and safety of drugs for treating bone-related diseases.</div><div>This strategy also opened the door for new methods of administering drugs. Traditionally, administering bone anabolic agents to treat bone fractures has relied entirely on local surgical application. However, because it is so invasive, this method’s use and development has been limited. By conjugating bone anabolic agents to bone-homing molecules, bone fracture treatment can be performed through minimally invasive subcutaneous administration. The exposure of raw hydroxyapatite that occurs with a bone fracture allows these high-affinity molecules to chelate the calcium component of hydroxyapatite and localize primarily to the fracture site.</div><div>Many bone-homing molecules (such as bisphosphonates and tetracycline targeting) have been developed to treat osteoporosis. However, many of these molecules have toxicity associated with them. We have found that short oligopeptides of acidic amino acids can localize to bone fractures with high selectivity and with very low toxicity compared to bisphosphonates and tetracyclines.</div><div>We have also demonstrated that these molecules can be used to target peptides of all chemical classes: hydrophobic, neutral, cationic, anionic, short, and long. This ability is particularly useful because many bone anabolics are peptidic in nature. We have found that acidic oligopeptides have better persistence at the site of the fracture than bisphosphonate-targeted therapeutics. This method allows for a systemic administration of bone anabolics to treat bone fractures, which it achieves by accumulating the bone anabolic at the fracture site. It also opens the door for a new way of treating the prevalent afflictions of broken bones and the deaths associated with them.</div><div>We further developed this technology by using it to deliver anabolic peptides derived from growth factors, angiogenic agents, neuropeptides, and extracellular matrix fragments. We found several promising therapeutics that accelerated the healing of bone fractures by improving the mineralization of the callus and improving the overall strength. We optimized the performance of these molecules by improving their stability, targeting ligands, linkers, dose, and dosing frequency.</div><div>We also found that these therapeutics could be used to accelerate bone fracture repair even in the presence of severe comorbidities (such as diabetes and osteoporosis) that typically slow the repair process. We found that, unlike the currently approved therapeutic for fracture healing (BMP2), our therapeutics improved functionality and reduced pain in addition to strengthening the bone. These optimized targeted bone anabolics were not only effective at healing bone fractures but they also demonstrated that they could be used to speed up spinal fusion. Additionally, we demonstrated that acidic oligopeptides have potential to be used to treat other bone diseases with damaged bone.</div><div>With these targeted therapeutics, we no longer have to limit bone fracture healing to casts or invasive surgeries. Rather, we can apply these promising therapeutics that can be administered non-invasively to augment existing orthopedic practices. As these therapeutics move into clinical development, we anticipate that they will be able to reduce the immobilization time that is the source of so many of the deadly complications associated with bone fracture healing, particularly in the elderly.</div>