Analysis of outcomes in extraskeletal osteosarcoma: a review of fifty-three cases.

BACKGROUND: Extraskeletal osteosarcoma is a rare soft-tissue sarcoma about which little is known. The objectives of this study were to describe the clinical features and natural history of extraskeletal osteosarcoma and to investigate factors affecting outcomes. METHODS: A retrospective review of a prospectively maintained database of patients diagnosed with soft-tissue sarcoma was conducted. Patients with pathologically confirmed extraskeletal osteosarcoma from 1982 to 2012 were identified and were included in the analysis. Medical records were reviewed for clinical features, treatment, and outcomes. RESULTS: Fifty-three patients were identified from the database: forty-two presented with localized disease, two presented with metastatic disease, and nine presented with recurrent (local and/or distant) disease. The median patient age at diagnosis was sixty-four years, with a median follow-up time of thirty-four months (range, one to 290 months) for survivors. Of the fifty-three patients who were identified, forty-one had lesions in the extremities, fifty-one had high-grade lesions, forty had lesions >5 cm, and forty-two had deep lesions. For patients presenting with localized disease, the median survival was 45.8 months with a three-year cumulative incidence of death due to disease of 39%. All patients with localized disease were managed with surgical resection of the primary tumor: nineteen with surgery only, ten with adjuvant radiation, five with adjuvant chemotherapy, and eight with both radiation and chemotherapy. Eighteen patients relapsed: two patients had local recurrences, ten patients had distant metastases, and six patients had local recurrences and distant metastases. In log-rank analysis, patients with superficial tumors and negative margins at resection had a higher three-year event-free survival. No significant association of disease-specific or event-free survival was found with the addition of radiation, chemotherapy, or both to surgery. CONCLUSIONS: For patients presenting with localized extraskeletal osteosarcoma, three-year event-free survival was higher for patients with superficial tumors and negative margins at resection. Radiation and chemotherapeutic treatment were not associated with a lower incidence of death due to disease or a longer event-free survival.

Primary versus secondary distal femoral arthroplasty for treatment of total knee arthroplasty periprosthetic femur fractures.

Current methods of fixing periprosthetic fractures after total knee arthroplasty (TKA) are variable, and include open reduction and internal fixation (ORIF) via plating, retrograde nailing, or revision using standard revision TKA components or a distal femoral arthroplasty (DFA). The purpose of this study is to compare patients who failed plating techniques requiring subsequent revision to DFA to patients who underwent primary DFA. Of the 13 patients (9.2%) who failed primary ORIF, causes included nonunion (53.8%), infection (30.8%), loosening (7.7%), and refracture (7.7%). There were significantly more surgical procedures for ORIF revision to DFA compared to primary DFA. Complications for patients who underwent primary reconstruction with DFAs included extensor mechanism disruption (8.3%), infection (5.6%), and dislocation (2.8%). Primary reconstruction via ORIF is beneficial for preserving bone stock, but primary DFA may be preferred in osteopenic patients, or those at high risk for nonunion.

Variation of nerve to flexor hallucis brevis.

BACKGROUND: Hallopeau's nerve is a branch of the lateral plantar nerve that supplies the flexor hallucis brevis muscle while also forming an anastomosis with the medial plantar nerve. In this study, the presence of this neural anastomosis was determined through dissection of cadaveric specimens. MATERIALS AND METHODS: Twenty-six fresh-frozen adult feet (13 matched pairs) were dissected to assess the presence or absence of Hallopeau's nerve. RESULTS: Dissections revealed four out of 26 specimens had this anastomosis. CONCLUSION: This study confirms this anatomic variation. CLINICAL RELEVANCE: The clinical significance of these anastomoses remains unknown. These anastomoses are analogous to some in the hand and forearm.

N-linked oligosaccharides affect the enzymatic activity of CD39: diverse interactions between seven N-linked glycosylation sites.

Rat CD39, a membrane-bound ectonucleoside triphosphate diphosphohydrolase that hydrolyzes extracellular nucleoside tri- and diphosphates, has seven potential N-glycosylation sites at asparagine residues 73, 226, 291, 333, 375, 429, and 458. To determine their roles in the structure and function of CD39, we mutated these sites individually or in combination by replacing asparagine with serine or glutamine and analyzed the surface expression and the enzymatic activity of the mutants. The results indicate that rat CD39 can be glycosylated at all seven sites when expressed in COS7 cells. Glycosylation sites 73 at the N terminus, 333 in the middle, and 429 and 458 at the C terminus were principally required for cell surface appearance of enzymatically active CD39. Whereas deletion of these sites individually had modest effects on surface ATPase activity, some double deletions of these sites had major effects on both surface activity and expression. The importance of these N-glycosylation sites is recognizable in other members of the ectonucleoside triphosphate diphosphohydrolase family.