The experimental determination of residual stress fields on the surface of retrieved femoral heads represents a fundamental step in understanding their wear degradation behavior and the tribological mechanisms, which are operative on the femoral joint during its working life time. In this work, the surface of retrieved alumina and zirconia (Al2O3 and ZrO2) femoral heads were investigated by piezo-spectroscopic tecniques based both on photoluminescence and Raman effects. The high spatial resolution of the laser, impinging on the investigated surface (typically about 1 micron of lateral resolution), enabled us estimating patterns and magnitude of residual stress in extremely narrow zones, comparable with the grain size of the material.

Four retrieved ceramic femoral heads were analyzed. Two balls were made of alumina with a typical grain size of from 4 to 10 microns. Both alumina balls were retrieved after only few years from implantation, due to septic and aspetic loosening. The remaining two femoral heads were made of zirconia with a typical grain size of 1 micron. These latter balls were retrieved after 2 and 13 years, respectively (both for loosening problems). With a systematic collection of a large number of data on a microscopic level it was possible to assess the retrieved femoral heads in to to, thus extending the microscopic analysis to the entire joint.

In allumina balls retrieved after short time implantation, a macroscopic stress field was found, which arose from manufacturing, loading history, and the displacements acting on the femoral head during its lifetime. This stress field was completely overcome by a microscopic residual stress field due to local contacts (e.g., local shocks owing to microseparation, impinging and wear contacts). On the other hand, in zirconia femural heads, the major amount of surface deterioration after long-term exposure arose from tetragonal-to-monoclinic transformation in biological environment. These data allowed us to draw interesting considerations about the role of the material microstructure and the peculiar kinematic mechanisms involved with the use of femoral heads made of different materials.

Spectroscopic techniques, which are complementary to in vitro testing procedures and stress analyses based on finite-element methods, can be very useful for improving the design of the femoral head and for optimizing the microstructural characteristics of the ceramic materials employed. Based on this and previous fluorescence and Raman spectroscopic studies, we also propose that a systematic screening of the ceramic implants before implantation can strongly reduce the probability of failure of the implant.

During the past fifty years metal hip implants have been used in orthopaedics. While these implants are considered biologically inert, several studies indicated that prosthetic implants could release metal ions following wear. The aim of this study was to evaluate serum and urine concentrations of metal ions in patients treated with hybrid surface replacement of the hip.

Co, Cr, Mn, Mo, and Ni in the serum and urine of 14 patients and 19 controls were quantified by Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS). A Spectrometer ELEMENT (Finnigan MAT, Bremen, Germany) was used at the following resolution: 98Mo, 100Mo, (m/D;m = 300); 52Cr, 53Cr, 55Mn, 59Co, 60Ni, (m/D;m = 3000). The internal standard method (In) was applied to correct the random fluctuations of the signal. Indium was added to the sample solutions so as to reach a final concentration of 1 ng mL-1. Limits of Detection were calculated on the basis of the 3=555; criterion for 10 replicate measurements of solutions containing dilute pooled blood serum and dilute pooled urine, and recovery was obtained by quantifying the analytes of interest in spiked serum and urine. Recoveries of the elements ranged between 94.6% (serum Cr) and 118% (urine Ni).

Data support the assumption that the concentrations of Co and Cr (the major components of the alloy) are substantially higher in serum and urine of patients than in those of controls while for the other elements no specific trend could be observed.

Actually there isn’t any explanation on the possible biological consequences related to the increase of the metal ions levels although many hypothesis have been made. Further studies are thus mandatory to clarify this pattern.

Alumina ceramic has been used in total hip arthoplasty since the 70’s and, in the last 30 years, a considerable evolution has occurred in designing the microstructural features of this material, taking advantage of improved processing techniques, as the hot isostatic pressing. As a result, a high degree of densification (> 99.5) has been achieved in materials with a high degree of purity and, especially, with a fine grain size ( 2 microns). The surface stress field acting on a femoral head inoperation is not only due to working conditions, but also to unexpected factors, as local impacts on the surface as a result of partial dislocations, formation of debris, etc. These additional factors greatly contribute to activate degradation mechanisms which, unfortunately, may lead to failure of the implant.

In this study, five alumina femoral heads were investigated, which were retrieved from patients after different periods of time. Among those investigated femoral heads, two belonged to a first-generation type of alumina material with a relatively coarse grainsize (average value 8 microns) and were retrieved due to surface degradation after long periods of implantation (19 and 17 years, respectively); the remaining three implants analyzed were instead recently manufactured implants with a fine grain size; they were retrieved after relatively short periods because of different causes as, for example, cup or stem loosening.

Surface stress analysis using the luminescence of Cr3+impurity in alumina was performed on the retrieved femoral heads and a statistical comparison was attempted among implants with different microstructural characteristics. The investigation led to estimate average residual stress and statistical stress distributions as a function of the location on the femoral head.

The analysis was performed both on the very surface and in the sub-surface of the head, using the confocal and the through-focus configurations of the optical spectrometer, respectively. Different statistical distributions of residual stress were observed in alumina femoral heads with different grain sizes and models were created to understand their dependence on processing and surface loading.

Aims: PMMA is currently used as grouting agent of arthroprostheses and for filling of bone cavities after bone curettage. It is moreover used as a carrier of antibiotics in the local treatment of bone infections and it has been proposed as a carrier of antiblastic drugs in the local treatment of bone metastases. The aim of this study is to analyse the biological properties and compressive strenght of PMMA-Methotrexate mixture to be used for the local treatment of bone metastases.

Methods: Cylinders of PMMA containing Methotrexate in different concentrations were manufactured according to ASTM F-451. Cylinders of PMMA were used as control. The porosity of the cylinders was characterised by SEM. Drug elution rate in saline solution was measured by HPLC. The biological activity of Methotrexate was analysed on human breast cancer cells using MTT test at different time (from 5 minutes to 30 days). Compressive tests was performed in conformity to ASTM F-451 on PMMA- Methotrexate samples and control as-made and after 30 days of aging in saline

Results: SEM analysis showed the presence of granules of Methotrexate on the surface of as-made cylinders that can be readily released from PMMA cylinders. The release occurred in large amount within 24 hours after immersion. We observed a relative release rate is more sustained in samples containing the drug in lower concentration. Also the biological activity was time dependent: cell death decreased progressively from 60% at 24 hours to 10% at 30 days.

Compressive tests showed no statistical differences between PMMA cylinders containing Methotrexate and controls before and after aging in saline.

Conclusions: The results show that PMMA-Metho-trexate may be considered an interesting option in the treatment of bone metastases because cement allows mechanical resistance after bone curettage or resection and Methotrexate improves locally anticancer activity.

In primary malignant bone tumours, the “en – block” excision with the sacrifice of soft tissues causes a functional deficit of the interested limb. There are many possibilities for reconstruction after a wide resection of the proximal humerus. The Authors report their experience using megaprostheses, focusing to soft tissue reconstruction, in order to obtain a good and fast functional recovery of the involved limb. 13 megaprostheses of the proximal humerus were employed. All patients were affected of primary malignant bone tumors with different histology. The tumor was staged according to Enneking’s system. 8 cases were classified as IIB and the remaining as IIA. All the tumors were treated with an intrarticular resection. Soft tissues reconstruction was performed, in 8 cases, using a mesh (Trevira tube), dressed all along the prosthesis, with a high resistance to traction. Radio and/or chemotherapy were employed referring to the histology.

At a medium follow – up of two years, for the surviving patients, we have obtained excellent functional results in 1 case, good in seven cases, fair in three cases and poor in two cases. The size of the resection is a main factor in order to obtain a good functional recovery of the joint motion. A wide excision (below deltoid insertion) with the sacrifice of large muscular masses and of the osteoarticular structures can represent a functional amputation causing the loss of muscles that are important to have an acceptable joint movement.

In our experience we retain that the use of modular prostheses in reconstructive orthopaedic surgery is advantageous because of its versatility and of its quick implantation, despite of other reconstructive systems. Moreover the use of a device, as that described, for an easy anchorage of the myotendinous structures, allows a quick functional recovery offering the patients considerable advantages for their social life.

Aims: Primary non-Hodgkin lymphoma of bone account for 5% of extra nodal lymphomas. The Authors report their experience referring to the results obtained with a multidisciplinary approach.

Materials: 18 cases of lymphoma of bone were included. Medium age was 63 yrs. All cases have been classified according to the REAL classification system. Patients have been staged with: total body CT scan, bone marrow aspirate, bone marrow biopsy, LDH serum level, skeletal survey and MRI of the skeletal segments involved. We treated 10 cases with solitary localization and 8 with multiple ones. Three patients presented with a pathologic fracture at diagnosis.

Chemotherapy protocols were:

MACOP-B < 60 yrs.

VNCOP-B > 60 yrs.

Seven patients received the PROMACE-CYTABOM protocol.

13 patients received EBRT (40 Gy). Ten patients received a surgical treatment: internal fixation in 7 cases and of spine stabilization in 3 cases

Results: At a medium follow-up of 40 months overall survival was 34,6 months and 14,5 months respectively for solitary or multiple localizations. Surgical treatment has been useful in improving performance status and in some cases to obtain a better control of the disease.

Discussion: In our experience bone lymphomas have always a high grade histology. Chemotherapy constitutes the treatment of choice. Surgical treatment have to be considered as a support treatment. Prognosis is worse in multiple localizations

Aim: The differential diagnosis between chondroma and grade I chondrosarcoma still represents a challenge. There are always cases in which a perfect diagnosis can’t be done for sure. This cases are defined in literature with different synonyms such as: borderline chondrosarcoma, grade 0 chondrosarcoma, atypical enchondroma or in situ chondrosarcoma. Enchondroma are benign lesions that do not require a surgical treatment. Low grade chondrosarcoma is a malignant tumour that can recur and also if in a low percentage of cases can metastasize. Methods: The Authors reviewed 22 cases of chondrosarcoma of the limbs for clinical, radiographycal and histological features. Results: Pain was present in 80% of cases of low grade chondrosarcoma, while was absent in enchondroma. Radiographic analysis was not significative. Bone scan was often positive in low grade chondrosarcoma as in enchondroma. Histology demonstrated a permeative pattern in chondrosarcoma with infiltration of the bone trabeculae. Conclusions: Only the complete evaluation of the patient resulted in a correct diagnosis. Follow-up of patients confirmed our findings