Zusammenfassung Das komplexe Fußtrauma ist selten und meist durch einen schweren Weichteilschaden gekennzeichnet. Hinzu kommen höhergradige knöcherne und neurovaskuläre Verletzungen sowie Gelenkbeteiligungen. Frühzeitig steht eine Entscheidung zwischen einer primären Amputation und Rekonstruktion in Vordergrund, in der Initialphase muss zwischen einer direkten definitiven Therapie und einem mehrzeitigen Vorgehen gewählt werden. Meist ist ein mehrzeitiges, interdisziplinäres Therapieregime erforderlich. Oberstes Ziel ist die Verhinderung des Fortschreitens der Ischämie mit Gewebeuntergang, Nekrose und Infektion. Operative Prinzipien beinhalten regelmäßige Débridements, frühzeitige plastische Weichteilrekonstruktionen und knöcherne Stabilisierungen meist durch externe Fixationen. Die knöcherne Rekonstruktion erfolgt von proximal nach distal mit anatomischer Rekonstruktion der Fußsäulen und stabiler innerer Fixierung.
The heparan sulphate proteoglycan syndecan-4 (Sdc4) has been associated strongly with osteoarthritis, a disease that mimics key aspects of early cartilage remodelling during endochondral ossification, but its role in embryonic and adult bone formation remains unclear. Therefore, we used Sdc4 -/- mice to analyse the distribution and functional role of Scd4 in endochondral ossification of mouse embryos and in adult fracture repair, which recapitulates endochondral ossification, but like osteoarthritis, involves an inflammatory component.
Methods
Sdc4 promoter activity was analysed in Sdc4 -/- /LacZ knock-in animals using β-galactosidase stainings. E16.5 embyros were used for histological (alcian blue/alizarin red) and immunohistological (PCNA, Col10a1, ADAMTS-4, BC-3, Sdc2) staining and the calcified bone area was quantified using whole mount staining of these embryos. Histological (Masson-Goldner, alcian blue) and immunohistological (Col10a1, Sdc2, PCNA) staining at day 7, 14 and 28 fracture calli were performed. These experiments were repeated with anti-TNF treatment during fracture healing. Callus size and cartilage area were quantified using image J Chondrocytes were isolated from neonatal knee joints and embyronal cartilage. Proliferation was investigated using MTT assay. Gene expression analysis for Sdc-2, Sdc-4 with and without stimulation using TNFα and WNT3a was performed using quantitative RT-PCR.
Results
In Sdc4 -/- /LacZ knock-in animals, Sdc4 promoter activity was detectable in all stages of chondrocyte differentiation during embryogenesis. Sdc4 deficiency inhibited chondrocyte proliferation both in vivo and in vitro, but this did not lead to a growth phenotype at birth. In contrast to embryogenesis, fracture healing in adult mice was markedly delayed in Sdc4 -/- animals and accompanied by increased callus formation. Analysing the discrepancy between the mild embryonic and the severe adult phenotype, we found a compensatory up-regulation of Sdc2 in the developing cartilage of Sdc4 -/- mice that was absent in adult tissue. Stimulation of chondrocytes with Wnt3a in vitro, led to an increased expression of Sdc2, while stimulation with TNFα resulted in an up-regulation of Sdc4 but a decreased expression of Sdc2. In consequence treatment with a blocking anti-TNF antibody during fracture healing abolished the difference in callus size between wildtype and sdc4 -/- mice.
Conclusions
We conclude that Sdc4 is functionally involved in endochondral ossification and that the loss of Sdc4 impairs adult fracture healing due to the inhibition of compensatory mechanisms under inflammatory conditions.
Hereditary multiple exostosis (HME) is an autosomal dominant disorder characterized by two or more benign growing, cartilage capped tumors of long bones called osteochondromas. If abnormal growth and clinical symptoms of osteochondromas newly appear in adults, malignant transformation of the usually benign growing tumors should be suspected and diagnostic testing should be initiated. Against the background of hypothesized higher malignant transformation of osteochondromas into chondrosarcoma in individuals with shoulder exostoses, we report a case of bilateral scapulothoracic osteochondromas in a patient suffering from HME. A 60-year-old female with HME complained of chest pain while being hospitalized for bilateral femoral fractures. A computed tomography scan of the chest was performed to rule out pulmonary embolism. However, bilateral osteochondromas in the scapulothoracic spaces were detected. Due to absence of radiographic evidences for malignant transformation in the patient, invasive diagnostic procedures such as biopsy and histological examination were recommended in order to exclude malignant transformation of both osteochondromas. Physicians should be aware that patients with HME who present with shoulder pain should be examined for osteochondromas in the scapulothoracic space. Due to possible sarcomatous transformation, regular follow-ups are necessary for adolescents and adults.
A fracture of the os peroneum is a rare cause of ankle and foot pain and is often overlooked and not assumed. Only a few case reports have discussed the different etiologies, options for diagnosis, and therapeutic interventions for acute cases. We present a case of delayed diagnosis of an os peroneum fracture due to a distortion of the ankle that occurred during air sports. Initial diagnostic testing with magnetic resonance imaging demonstrated a rupture of the peroneus longus tendon with no pathologic abnormalities at the peroneus brevis tendon. During surgery, a combination of an os peroneum fracture and a peroneus brevis tendon split was found and was successfully treated with bone and tendon repair using a lasso stich technique.
