Mechanical performance of dental amalgam--composite interfaces

Composite veneering of amalgam is the most aesthetical solution to extensive direct tooth restoration and is applied with success in specific clinical situations. An in-vitro technique has been used to evaluate the mechanical performance of one amalgam bonded to four different composites. The amalgam-composite interfaces were subjected to tensile stress and shear stress at break tests, using dumb-bell and sandwich specimens in a PC-controlled electronic dynamometer equipped with innovative grips. Mean values were higher for tensile stress than for shear stress. Further studies and clinical experimentation will be necessary to explore the question of long-term reliability.     

Failure rates and functional results for intercalary femur reconstructions after tumour resection

MUSCULOSKELETAL SURGERY - To compare the results for patients treated with intercalary endoprosthetic replacement (EPR) or intercalary allograft reconstruction for diaphyseal tumours of the femur...     

Pulpal effects of etching in the use of direct attachments

Recurring enamel etching was observed to value the effects on pulp response. Four teeth were extracted and analysed by O.M.; no cellular alterations were observed except a slight inflammatory alteration testified by congested vessels and presence of fibroblasts.     

Hoffa’s fat pad tumours: What do we know about them?

Purpose

We report on a group of patients with tumours in the Hoffa’s fat pad (HFP), their clinical presentation, histological type and treatment, including two synovial sarcomas with their clinical follow-up, which have not been described previously in the literature.

Methods

We performed a retrospective review of our prospectively collected database of 25 cases of HFP tumours with at least six months follow-up.

Results

The gender, age at presentation (over and under 16 years of age), clinical features, history of trauma, treatment chosen, and complications were recorded. The mean age of the patients was 32 years (three to 47). Six patients were under 16 years old. Pain was the most common symptom, present in 92 % (n = 23/25). The final diagnoses included 23 (92 %) benign tumours and two (8 %) malignant tumours. The most common benign tumour was pigmented villonodular synovitis (PVNS) (48 % n = 12). The two malignant tumours were synovial sarcomas and both presented in patients under 16 years old.

Conclusions

Hoffa’s fat pad tumours are an uncommon and rarely diagnosed group of lesions that can be misinterpreted as any knee pathology. Although the majority of HFP tumours are benign, malignant tumours should be considered in the differential diagnosis for the paediatric population.     

Proximal Tibia Reconstruction After Bone Tumor Resection: Are Survivorship and Outcomes of Endoprosthetic Replacement and Osteoarticular Allograft Similar?

Background

The proximal tibia is one of the most challenging anatomic sites for extremity reconstructions after bone tumor resection. Because bone tumors are rare and large case series of reconstructions of the proximal tibia are lacking, we undertook this study to compare two major reconstructive approaches at two large sarcoma centers.

Questions/purposes

The purpose of this study was to compare groups of patients treated with endoprosthetic replacement or osteoarticular allograft reconstruction for proximal tibia bone tumors in terms of (1) limb salvage reconstruction failures and risk of amputation of the limb; (2) causes of failure; and (3) functional results.

Methods

Between 1990 and 2012, two oncologic centers treated 385 patients with proximal tibial resections and reconstruction. During that time, the general indications for those types of reconstruction were proximal tibia malignant tumors or bone destruction with articular surface damage or collapse. Patients who matched the inclusion criteria (age between 15 and 60 years old, diagnosis of a primary bone tumor of the proximal tibia treated with limb salvage surgery and reconstructed with endoprosthetic replacement or osteoarticular allograft) were included for analysis (n = 149). In those groups (endoprosthetic or allograft), of the patients not known to have reached an endpoint (death, reconstructive failure, or limb loss) before 2 years, 85% (88 of 104) and 100% (45 of 45) were available for followup at a minimum of 2 years. A total of 88 patients were included in the endoprosthetic group and 45 patients in the osteoarticular allograft group. Followup was at a mean of 9.5 (SD 6.72) years (range, 2–24 years) for patients with endoprosthetic reconstructions, and 7.4 (SD 5.94) years for patients treated with allografts (range, 2–21 years). The following variables were compared: limb salvage reconstruction failure rates, risk of limb amputation, type of failures according to the Henderson et al. classification, and functional results assessed by the Musculoskeletal Tumor Society system.

Results

With the numbers available, after competitive risk analysis, the probability of failure for endoprosthetic replacement of the proximal tibia was 18% (95% confidence interval [CI], 10.75–27.46) at 5 years and 44% (95% CI, 31.67–55.62) at 10 years and for osteoarticular allograft reconstruction was 27% (95% CI, 14.73–40.16) at 5 years and 32% (95% CI, 18.65–46.18) at 10 years. There were no differences in terms of risk of failures at 5 years (p = 0.26) or 10 years (p = 0.20) between the two groups. Fifty-one of 88 patients (58%) with proximal tibia endoprostheses developed a reconstruction failure with mechanical causes being the most prevalent (32 of 51 patients [63%]). A total of 19 of 45 osteoarticular allograft reconstructions failed (42%) and nine of 19 (47%) of them were caused by early infection. Ten-year risk of amputation after failure for endoprosthetic reconstruction was 10% (95% CI, 5.13–18.12) and 11% (95% CI, 4.01–22.28) for osteoarticular allograft with no difference between the groups (p = 0.91). With the numbers available, there were no differences between the groups in terms of the mean Musculoskeletal Tumor Society score (26.58, SD 2.99, range, 19–30 versus 27.52, SD 1.91, range, 22–30; p = 0.13; 95% CI, ?2,3 to 0.32). Mean extension lag was more severe in the endoprosthetic group than the osteoarticular allograft group: 13.56° (SD 18.73; range, 0°–80°) versus 2.41° (SD 5.76; range, 0°–30°; p < 0.001; 95% CI, 5.8–16.4).

Conclusions

Reconstruction of the proximal tibia with either endoprosthetic replacement or osteoarticular allograft appears to offer similar reconstruction failures rates. The primary cause of failure for allograft was infection and for endoprosthesis was mechanical complications. We believe that the treating surgeon should have both options available for treatment of patients with malignant or aggressive tumors of the proximal tibia. (S)he might consider an allograft in a younger patient to achieve better extensor mechanism function, whereas in an older patient or one with a poorer prognosis where return to function and ambulation quickly is desired, an endoprosthesis may be advantageous.

Level of Evidence

Level III, therapeutic study.