Wnt signaling plays a central regulatory role across a remarkably diverse range of functions during embryonic development, including those involved in the formation of bone and cartilage. Wnt signaling continues to play a critical role in adult osteogenic differentiation of mesenchymal stem cells. Disruptions in this highly-conserved and complex system leads to various pathological conditions, including impaired bone healing, autoimmune diseases and malignant degeneration. For reconstructive surgeons, critically sized skeletal defects represent a major challenge. These are frequently associated with significant morbidity in both the recipient and donor sites. The Wnt pathway is an attractive therapeutic target with the potential to directly modulate stem cells responsible for skeletal tissue regeneration and promote bone growth, suggesting that Wnt factors could be used to promote bone healing after trauma. This review summarizes our current understanding of the essential role of the Wnt pathway in bone regeneration and repair.

In the present retrospective analysis of 643 patients with primary soft issue sarcomas of the extremities, surgical margins could be identified as independent predictors of local recurrence-free, disease-specific, and metastasis-free survival. Given the diminished outcome of patients left with positive margins, surgical efforts should aim to achieve microscopically negative margins whenever feasible. It is noteworthy that only the quality of surgical margins, but not the negative margin width attained, had an influence on the prognosis. Our findings suggest that surgical margins can be close as long as the resected tumor has no ink on it.

IntroductionSolid malignancies at the foot and ankle region are rare and include mainly soft-tissue sarcomas, bone sarcomas, and skin malignancies. Complete surgical resection with clear margins still remains the mainstay of therapy in these malignancies. However, attainment of negative surgical margins in patients with locally advanced tumors of the foot and ankle region may require extensive surgery and could result in loss of extremity function. In these circumstances, plastic surgical techniques can frequently reduce functional impairment and cover soft-tissue defects, particularly in cases of large tumor size or localization adjacent to critical anatomic structures, thereby improving the quality of life for these patients. The aim of this article is to illustrate the various treatment options of plastic surgery in the multimodal therapy of patients with malignant tumors of the foot and ankle region.Materials and methodsThis article is based on the review of the current literature and the evaluation of the author’s own patient database.ResultsThe local treatment of malignant extremity tumors has undergone major changes over the last few decades. Primary amputations have been increasingly replaced by limb-sparing techniques, preserving extremity function as much as possible. Although defect coverage at the foot and ankle region is demanding due to complex anatomical features and functional requirements, several plastic surgical treatment options can be implemented in the curative treatment of patients with malignant solid tumors in this area. Soft-tissue defects after tumor resection can be covered by a variety of local flaps. If local flaps are not applicable, free flap transfers, such as the anterolateral thigh flap, parascapular flap, or latissimus dorsi flap, can be utilized to cover nearly all kinds of defects in the foot and ankle region.ConclusionSoft-tissue reconstruction in the foot and ankle region is a vital component of limb-sparing surgery. It enables complete resection of locally advanced tumors and subsequent adjuvant radiotherapy. Modern plastic surgical techniques should, therefore, be integrated in the multimodal treatment concept of malignancies in the foot and ankle region.

Background:The aim of this study was to identify prognostic indicators of survival in patients with locally recurrent soft tissue sarcoma (STS) through a long-term follow-up.Methods:We retrospectively assessed the relationship between post-recurrence survival (PRS) and potential prognostic factors in 135 patients who had experienced local recurrence, which was suitable for further surgical treatment. The median follow-up time after initial recurrence was 12.3 years (95% confidence interval (CI): 10.4–14.2 years).Results:The 5-year estimate of the PRS rate was 53.1% (95% CI: 44.3–61.2%) for the entire series. Patients with negative margins after the final surgery experienced improved survival compared with patients with positive margins (5-year survival: 46.7% (35.2–57.5%) vs 35.5% (23.4–47.8%); P=0.01). In a multivariate analysis, the significant prognostic indicators for PRS were histologic grade, tumour site, time to initial recurrence, the number of recurrences and the surgical margin status attained at the last resection.Conclusions:Complete surgical resection with microscopically clear margins is desirable in patients with locally recurrent STS. However, when achieving clear surgical margins will require major functional impairment of the extremity, a radical surgical approach should be weighed for the patient in each case.

IntroductionSurgical treatment of malignant thoracic wall tumors represents a formidable challenge. In particular, locally advanced tumors that have already infiltrated critical anatomic structures are associated with a high surgical morbidity and can result in full-thickness defects of the thoracic wall. Plastic surgery can reduce this surgical morbidity by reconstructing the thoracic wall through various tissue transfer techniques. Sufficient soft-tissue reconstruction of the thoracic wall improves quality of life and mitigates functional impairment after extensive resection. The aim of this article is to illustrate the various plastic surgery treatment options in the multimodal therapy of patients with malignant thoracic wall tumors.Materials and methodsThis article is based on a review of the current literature and the evaluation of a patient database.ResultsSeveral plastic surgical treatment options can be implemented in the curative and palliative therapy of patients with malignant solid tumors of the chest wall. Large soft-tissue defects after tumor resection can be covered by local, pedicled, or free flaps. In cases of large full-thickness defects, flaps can be combined with polypropylene mesh to improve chest wall stability and to maintain pulmonary function. The success of modern medicine has resulted in an increasing number of patients with prolonged survival suffering from locally advanced tumors that can be painful, malodorous, or prone to bleeding. Resection of these tumors followed by thoracic wall reconstruction with viable tissue can substantially enhance the quality of life of these patients.DiscussionIn curative treatment regimens, chest wall reconstruction enables complete resection of locally advanced tumors and subsequent adjuvant radiotherapy. In palliative disease treatment, plastic surgical techniques of thoracic wall reconstruction provide palliation of tumor-associated morbidity and can therefore improve patients’ quality of life.

Background: Undifferentiated pleomorphic sarcomas are a frequent subtype within the heterogeneous group of soft tissue sarcomas. As the attainment of negative margins can be complicated at the extremities, we determined the prognostic significance of surgical margins in our patient population. Methods: We retrospectively determined the relationship between local recurrence-free survival (LRFS), overall survival (OS), and potential prognostic factors in 192 patients with UPS of the extremities who were suitable for surgical treatment in curative intent. The median follow-up time was 5.1 years. Results: The rates of LRFS and OS after 2 years were 75.7% and 87.2% in patients with R0-resected primary tumors and 49.1% and 81.8% in patients with R1/R2-status (LRFS: p = 0.013; OS: p = 0.001). Adjuvant radiotherapy significantly improved LRFS (5-year: 67.6% vs. 48.4%; p < 0.001) and OS (5-year: 82.8 vs. 61.8; p = 0.016). Both, negative margins and adjuvant radiotherapy were found to be independent prognostic factors in multivariate analysis. Conclusions: The data from this study could underscore the beneficial prognostic impact of negative margins on LRFS and OS. However, the width of negative margins seemed to be not relevant. Notably, adjuvant radiotherapy was not only able to decrease the risk of local failure but also improved OS in a significant manner.

Bone regeneration is typically a reliable process without scar formation. The endocrine disease type 2 diabetes prolongs and impairs this healing process. In a previous work, we showed that angiogenesis and osteogenesis-essential steps of bone regeneration-are deteriorated, accompanied by reduced proliferation in type 2 diabetic bone regeneration. The aim of the study was to improve these mechanisms by local application of adipose-derived stem cells (ASCs) and facilitate bone regeneration in impaired diabetic bone regeneration. The availability of ASCs in great numbers and the relative ease of harvest offers unique advantages over other mesenchymal stem cell entities. A previously described unicortical tibial defect model was utilized in diabetic mice (Lepr db2/2 ). Isogenic mouse adiposederived stem cells (mASCs) db2/db2 were harvested, transfected with a green fluorescent protein vector, and isografted into tibial defects (150,000 living cells per defect). Alternatively, control groups were treated with Dulbecco's modified Eagle's medium or mASCs WT . In addition, wild-type mice were identically treated. By means of immunohistochemistry, proteins specific for angiogenesis, cell proliferation, cell differentiation, and bone formation were analyzed at early (3 days) and late (7 days) stages of bone regeneration. Additionally, histomorphometry was performed to examine bone formation rate and remodeling. Histomorphometry revealed significantly increased bone formation in mASC db2/db2 -treated diabetic mice as compared with the respective control groups. Furthermore, locally applied mASCs db2/db2 significantly enhanced neovascularization and osteogenic differentiation. Moreover, bone remodeling was upregulated in stem cell treatment groups. Local application of mACSs can restore impaired diabetic bone regeneration and may represent a therapeutic option for the future. STEM CELLS TRANSLATIONAL MEDICINE 2016;5:836-844 SIGNIFICANCEThis study showed that stem cells obtained from fat pads of type 2 diabetic mice are capable of reconstituting impaired bone regeneration in type 2 diabetes. These multipotent stem cells promote both angiogenesis and osteogenesis in type 2 diabetic bony defects. These data might prove to have great clinical implications for bony defects in the ever-increasing type 2 diabetic patient population.

The data from this study could not determine a prognostic significance of surgical margins suggesting that tumour characteristics other than margin status are important. Tumour biology reflected by the histologic grade dictates the final outcome.