The development and introduction of the closed locked intramedullary nail into clinical practice has revolutionized the treatment of fractures of long bone. The most difficult and technically demanding part of the procedure is often the insertion of the distal interlocking screws. A lot of efforts have been made during the past years to make it easier. In according with Whatling and Nokes, we can divide the different approaches to this issue in four main groups:

Free-hand (FH) technique;

In addition of these, recently it has been proposed a navigational system using electromagnetic field.

The main disadvantages of the FH technique, are prolonged exposure to radiation and results depend mostly on the dexterity of the surgeons. FH technique is however the most popular technique.

Our targeting device is included into the mounted on image intensifier group. It consists of 2 radio-opaque rods at right angle to each over: one of this is fixed on the c-arm, whereas, the other is a sliding rod with a sleeve for the drill bit, which is the targeting guide itself. In the realization of this device, we have been inspired by the modification of the FH technique suggested by Kelley et al. To identify the distal holes we used the method described by Medoff (perfect circle). Once that the distal hole is seen as a perfect circle, with the C-arm in later view, the targeting guide is roughly positioned onto this and the drilling and the screwing operations are performed without the need for image intensifier. We used the device in bone models and in 9 clinical cases.

In spite of authors demonstrated that the electromagnetic targeting device significantly reduced radiation exposure during placement of distal interlocking screws and was equivalent in accuracy when compared with the FH technique, the latter is the most used technique. Indeed, although all the studies have reported that the radiation exposure to orthopedic surgeon has been below the maximum allowable doses in all cases, there is still the risk of cumulative lifetime radiation exposure. From this point of view, namely the reduction of cumulative lifetime radiation exposure, we think that, paradoxically, our device could be more effective than electromagnetic targeting device, because it can be used in all the orthopedic operations that required a targeting device.

The study of the chondrocyte maturation cycle and endochondral ossification showed that the developing vascular supply has appeared to play a key role in determining the cortical or trabecular structure of the long bones.

The chondrocyte maturation cycle and endochondral ossification were studied in human, foetal cartilage anlagen and in postnatal meta-epiphyses. The relationship between the lacunar area, the inter territorial fibril network variations and CaP nucleation in primary and secondary ossification centres were assessed using light microscopy and SEM morphometry. The anlage topographic, zonal classification derived from the anatomical nomenclature of the completely developed long bone (diaphysis, metaphyses and epiphyses) allowed to follow the development of long bones cartilage model. A significant increase in chondrocyte lacunar area (p<0.001) was documented from the anlage epiphyseal zone 4 and 3 to zone 2 (metaphysis) and zone 1 (diaphysis), with the highest variation from zone 2 to zone 1. An inverse reduction in the intercellular matrix area (p<0.001) and matrix interfibrillar empty space (p<0.001) was also documented. These findings are consistent with the osmotic passage of free cartilage water from the interfibrillar space into the swelling chondrocytes, raising ion concentrations up to the critical threshold for mineral precipitation in the matrix. The mineralised cartilage served as a scaffold for osteoblasts apposition both in primary and secondary ossification centres and in the metaphyseal growth plate cartilage, but at different periods of bone anlage development and with distinct patterns for each zone. They all shared a common initial pathway, but it progressed with different times, modes and organisation in diaphysis, metaphysis and epiphysis. In the ossification phase the developing vascular supply has appeared to play a key role in determining the cortical or trabecular structure of the long bones.

Aims: Cartilage lesions do not repair spontaneously. Despite the high number of surgical and tissue engineering approaches that have been applied to promote articular cartilage (AC) regeneration, none of them, at present, have shown durable satisfactory results. In the present study an innovative technology, the RCCS™ bioreactor (Synthecon, Inc.), was employed to develop a 3D culture model suitable for the long-term in vitro maintenance of AC explants. Based on the principle of relative microgravity, the RCCS™ bioreactor, in fact, creates a microenvironment that, by preserving the complexity of original cell-cell and cell-matrix interactions, closely mimics the original tissue-specific biophysical conditions needed for proper cellular activities and morphogenesis.

Methods: Newborn rabbits were used as AC donors (femoral head). The explants, collected under sterile conditions and sectioned into 1–3 mm³ fragments, were immediately processed for structural/molecular analyses (T0) or kept for up to 4 weeks in the RCCS™ bioreactor (3D culture). The cultured fragments were harvested after 2, 4, 7 days and after 2, 3 and 4 weeks of culture. Comparative histochemical and molecular analyses were then performed on samples from each experimental point to assess the viability/differentiation pattern of their cellular components, as well as the structural integrity of the extracellular matrix.

Results: Our results demonstrated that, for the whole period of culture, the samples maintain the typical features of hyaline AC, with no significant signs of cell suffering or degenerative changes.

Conclusions: The dynamic 3D culture model employed in our study open promising perspectives either for providing new insight into AC physiopathology, or for developing efficacious intervention strategies for the treatment of AC disorders.

Aims: The shape and the structure of cortical bone of the diaphysis is the result of the continual resorption/ replacement process where the two phases have well regulated temporal sequence and spatial localization. Different methods can be employed to measure the appositional growth but their possible application to structural studies has not been so far considered.

The broad interest of this study was addressed to the mechanisms which control the structural modelling of cortical bone in the course of the long growth and development, therefore a morphometric evaluation appeared the more suitable method for the possibility to examine large segments of the bone.

Methods: The study was carried out on the femurs of four male New Zealand white rabbits. The left femurs were prepared with the techniques for undecalcified bone and studied in incedent fluorescent light. The right femurs were decalcified, prepared in sections and studied in bright field, in polarized light and in phase contrast.

Ditigital microscope images were analyzed utilizing the software Cell D: the cortical area was measured and the number of vascular canals was counted and expressed as a function of the cortical area (n/mm²). The total cortical area, the density of vascular canals and the frequency distribution for area classes in the cortex of mid-shaft and distal-shaft was compared with paired student t test and Pearson chi-square test respectively.

Results and Conclusions: The canals distribution for area classes showed a significant prevalence for actually structuring osteons in the distal shaft: these data demonstrate the higher rate of bone remodelling of the most recent apposed bone at the extremities of the shaft. On the contrary there were not significant differences among sectors at levels of the mid-shaft and distal-shaft.

The purpose of this study was to evaluate the long-term results of isolated closed Mason type-II and III fractures treated by internal fixation or by radial head resection.

METHODS: A long-term retrospective study was undertaken of eighty-seven patients with a Mason type-II and type-III isolated closed fracture of the radial head. Fifty of them were treated by radial head resection, two by excision of the fracture’s fragment and thirty-five of them by internal fixation. The average length of follow-up was 92.25 months. The patients were divided into two homogeneous groups, of which group 1 was made up of fifty-two patients treated by capitellectomy and by excision of the fracture’s fragment, and group 2 was made up of thirty-five patients treated by osteosynthesis.

The patients were submitted to clinical and radiographic evaluation. The subjective outcome was assessed with the DASH questionnaire (Disabilities of Arm-Shoulder-Hand); elbow pain on loading and at rest (VAS scale); and tenderness, loss of strength, and range of motion of the affected elbow. The uninjured arm served as the control. Flexion and extension of the elbow and the wrist, pronation and supination of the forearm, and the angle of the extended/flexed elbow were measured with a goniometer. Grip strength of the hand was evaluated with the Jamar vigorimeter. The radiographic evaluation included antero-posterior and lateral projections of the elbow and antero-posterior of the wrist.

RESULTS: The previously injured elbows in group 1 had an average loss of flexion of 14.61° and an average loss of extension of 8.65° compared with the uninjured, and there was less pronation of the forearm on the injured side (4.81°) and less supination (9.04°). Instead the injured elbows in group 2 had an average loss of flexion of 3.71° compared with the uninjured and an average loss of extension of 2°, which is minimal, and there was a further minimal loss of pronation of 1° and loss of supination of 0.86°.

In group 1, the definate average DASH value was 21.26, much higher than the value of 2.81 found in group 2. The VAS average value was also superior in the group 1 (3.87) compared with group 2 (1.2).

We also evaluated, in direct manner, the instability of the injured elbow using the valgus-stress test, which revealed a slight instability (48%) and a moderate instability (35%) of group 1. No instability however was found in group 2.

With regard to radiographic analysis, radiographic signs of arthrosis were present in 90% of patients who had undergone capitellectomy, and in 16% of those who had undergone osteosynthesis.

CONCLUSION: The patients in whom the radial head fracture was treated with open reduction and internal fixation had satisfactory joint motion, with greater strength and better function than the patients who had undergone radial head resection.

A stiff prosthetic stem in the proximal femur alters the load-bearing model af the bone and leads to changes of the lamellar organization, known as “stress shielding”.

To avoid this problem in the 70th a stem with a higher elastic modulus was developed and implanted in patiens (isoelastic stem of Mathys and Morscher).

A group of 17 isoelastic stems of this type which have remained in the femur from 6 to 8 years, were removed and are the object of the study. Analysis of the polyacetile surface was carried out with a low enlargement microscope. The stems were then radiographed and cut with a low speed saw to investigate structural changes between the polyacetile cover and the steinless steel core.

Two type of material lesions were observed:

- loss of polyacetile material from the surface (wear)

Distribution and frequency of each type of lesion was registerd in relation to four zones of the stem: a) cone with the metallic head; b) proximal stem (metaphyseal); c) body of the stem (diaphyseal); a)apex of the stem.

Wear of the polyacetile stem is evidence that no fixation of the stem was achieved, therefore a fraction of the load energy was dissipated at the prosthesis-endosteal surface.

However the presence of structural yielding lesions demonstrate that another fraction of the load energy was carried out by the stem. The topography of these lesions allowed to understand the biomechanical behavior of the “isoelastic” stem inside the femur with vertical longitudinal (piston) and rotational in the horizontal plane movements.

Failure of polyacetile and decoupling of polyacetile cover and stainless steel core were the other main findings.

The theory of an isoelastic stem is appealing by a biomechanical point of view, however two practical problems caused failure in this series: 1) lack of fixation at the implant-bone interface; 2) failure of materials.

This study is based on 286 consecutive fractures of the shaft of the humerus surgically treated in the Orthopaedic Department Spedali Civili, Brescia, from November 1996 to December 2001.

Fractures were classified accordingly to AO System.

A peculiar group was represented by 33 (11.5%) complex and multifragmental fractures, where the fracture involved either the shaft and the proximal metaphysis and epiphysis.

Fractures were always treated by plate and screws when a deficit of the radial nerve was present, in order to allow neurolysis or nervous graft.

Fractures without radial nerve lesion were treated either by plate or by endomedullary nail.

In the latter group two typed of nail were used:

rigid, reamed, Kuntscher nail inserted through the proximal epiphysis

elastic nail, type Marchetti-Vicenzi, inserted through a posterior, distal humeral approach.

Patients were evaluated with a follow-up of a least 1 year.

The rate of fracture consolidation, was similar in the group 1 rigid nail (96.5%) and plate (96.9%), while lower in the group of elastic nail (89.1%).

Also time of consolidation and functional recovery was similar in the first two groups.

Particular problems presented by the group of complex fractures required a differentiated post-surgical treatment, with plaster cast or orthopaedic devices used as adjuvant mode of immobilization. All except one of these cased consolidated in a larger lapse of time (mean 4.5 months) with the following functional results: 36.5% very good; 18.1% good; 9.1% fear; 36.3% poor. A selection of the technical solution adopted is presented.