Introduction

the aim of the study is to evaluate the clinical results of the shoulder prosthesis revision procedure to reverse implant without removing the humeral stem using a modular system (Lima LTD) and determine if this procedure is beneficial for the patients.

A particular pattern of complex instability of the elbow is “the terrible triad”, in which elbow dislocation is associated with fractures of the coronoid and radial head. Other frequent patterns are the variant of Monteggia lesions (Bado II) described by Jupiter which is characterized by ulnar fracture associated with fracture-dislocation of proximal radius, and the articular fracture of the distal humerus associated with elbow dislocation. The goal of treatment is to restore the primary stabilizers of the elbow such as the coronoid process, olecranon and both collateral ligaments by internal fixation and reconstruction of the ligaments. If elbow stability obtained at operation is unsatisfactory or internal fixation not enough stable, there an indication for applying a dynamic external fixator (DEF). The latter allows:

the articular congruence to be maintained and the ligaments to heal in adequate tension and position,

From 2005 to 2008, we treated surgically 31 patients with complex instability of the elbow. DEF was applied in 38% of cases, namely 3 terrible triads, 5 fracture-dislocations of Monteggia and 4 articular fractures of the humerus associated with elbow dislocation. The mean age of patients was 44 years (range 30–74). All patients underwent ORIF, reconstruction of ligaments and dynamic external fixation. The OptiROM elbow fixator was used In 2 patients, the Orthofix fixator in 1 and the DJD fixator in 9. In all cases, active elbow motion was allowed without restrictions from the second postoperative day. Indomethacin was consistently administered for 5 weeks to prevent heterotopic ossifications. The DEF was removed after 6 weeks. The mean follow-up was 25 months (range 5–44 months). At last follow-up, the clinical results, evaluated according to the MEPS, were excellent in 10 patients (83%), who had had a fast recovery of range of motion (ROM). The elbow was painless in all patients and stable in all but 1. Moderate osteoarthrosis was found in 60% of cases. Complications included: 1 elbow stiffness, 1 pseudarthrosis of capitulum humeri and trochlea, 1 transitory radial nerve palsy, and 1 superficial pin tract infection.

In conclusion, DEF is a helpful tool for treatment of complex elbow instability, particularly when stable internal fixation cannot be obtained or instability persists after ligaments reconstruction. However, DEF increases morbidity, and implies a longer operative time and prolonged exposure to radiation.

Purpose: Treatment of radial head fractures of Mason Type II and III involving the neck of the radius is still controversial, especially in the presence of comminution. ORIF often gives unsatisfactory results because of the difficulty in restoring the head-neck off-set and the radial head inclination relative to its neck. In these cases radial head replacement may be indicated ; however, there are no long-term studies on complications and survival of the implant. Recently precontoured plates for the proximal radius has been introduced but no trials have determined whether they are able to restore the normal anatomy of the radius. The latter is still partially unknown because no studies have analyzed the morphology of posterolateral aspect of radial head and neck (“safe zone”). Our study was aimed at:

determining the possible presence of anatomical variations of the safe-zone and

Material and Methods: Measurements, performed on 44 cadaver dry radii of adults, included: length of the radius, diameters and height of the radial head, and height and diameter of the neck of the radius. The radius of bending of the safe zone was also calculated.

Results: The morphological evaluation of the “safe zone” of the radius revealed 3 different morphological types of this zone:

(flat) (25 %),

Adherence of a precoundered plate (Acumed) to the bone surface of the safe zone was performed independently by three of us, and the gap between plate and bone was measured. Plate adaptability was good in Type B, scarce in Type C and absent in Type A.

Conclusion: In conclusion, we identified 3 different morphologies of the safe zone, not previously described, and we found that the precountered plates now available can ensure a good restoration of anatomy only in the half of the human radii.

Aims: Aims of this study was to perform a quantitatively evaluation of newly formed bone, vascular density (VD) and their correlation in animal model of posterolateral spinal fusion based on skeletal stem cells (SSCs) combined with a coral.

Methods: 15 rabbits received cell-material constructs, 15 rabbits were sham-operated (decortication of transverse apophyses), 15 rabbits received material alone. After 6 months the animals were sacrified. We performed a semi-quantitative and quantitative histologycal analysis of the fusion mass. To assess the VD, sections of the fusion mass were immunolabelled for alpha-smooth muscle actin as a vascular marker.

Results: No complete fusion was observed in all groups and no bone was formed in the interapophyseal region. Aboundant newly formed bone was observed in the peri-apophyseal regions in 60% of cases. The quantitative analysis showed a significantly higher amount of bone and VD in animals treated with cells and/or biomaterial alone compared to sham (p< 0.05). Periapophyseal VD and new bone formation was significantly higher compared to interapophyseal region in all groups (p< 0.05). Positive correlation exist between newly formed bone and vascolar density (p = 0,0009).

Conclusions: Interapophyseal region is scarcely vascolarized. The study shows a positive correlation between VD and osteogenesis. The inadequacy of staminal cells could be related with the poor survival after the implant. For the use of stam cells in the APL are necessary more studies in order to clarify the survival and in situ differentiation of the grafted cells in short and mid term.

Posterolateral spinal fusion is considered one of the most challenging condition for bone graft substitutes since using autogenous bone graft pseudarthrosis have been reported in 30% of cases.

MATERIALS AND METHODS.We develop a model of posterolateral spinal fusion in the rabbit based on skeletal stem cells (SSCs) loaded into a coral-hydroxyapatite material (Pro-Osteon 500RTM). 15 rabbits received cell-material constructs, 15 rabbits were sham-operated (decortication of transverse apophyses), 15 rabbits received material alone. The animals were housed for 6 months and radiographically monitored. At sacrifice, the explanted spine was analyzed by conventional and high resolution (Faxitron) radiography, and the outcome judged, blind of histology results, by two orthopedic surgeons.

RESULTS: radiographic evaluation showed a fusion rate rate of 90% in animals treated with cell constructs or biomaterial alone, and no fusion in the sham controls. Histology revealed abundant new bone formation directly on the scaffold in the cell construct and biomaterial alone groups, but no evidence of bone formation in the midregion of the interapophyseal space, where poorly vascular, dense fibrous tissue was observed.

CONCLUSIONS: The study shows that:

1) the cell-biomaterial constructs which per se were highly efficient in previous animal studies, used in different absolute quantities but identical ratios were not efficient in the direct preclinical model.

Degenerative spondylolisthesis is consistently responsible for narrowing of the spinal canal, but only in a part of the cases it causes lateral or central stenosis. The presence, type and severity of stenosis is related to several factors, such as the constitutional dimensions of the spinal canal, the orientation and severity of degenerative changes of the facet joints, and the amount of vertebral slipping. The type of stenosis, that is whether stenosis is central or lateral, depends on the orientation of the articular processes, and the length of the pedicles. Usually stenosis is lateral initially and central in later stages. Instability, that is hypermobility on flexion-extension adiographs is one of the main characteristics of degenerative spondylolisthesis. However, in many cases there is no appreciable hypermobility of the slipped vertebra. We consider the latter condition as a potential instability, which can become a manifest instability as a result of surgery, or when destabilizing factors unable to destabilize a normal vertebra intervene, such as disc degeneration or severe degenerative changes of the facet joints.

There is no indication for surgery in patients with no significant symptoms. In patients with an unstable motion segment who have only back pain it is usually sufficient to perform a fusion alone if stenosis is mild and asymptomatic. Neural decompression should be performed if stenosis is severe. Bilateral laminotomy, or even total laminectomy, may be carried out with no concomitant fusion in patients with mild olisthesis, no vertebral hypermobility on functional radiographs, mild central stenosis or any degree of isolated lateral stenosis, and mild or no back pain. The indications for monolateral laminotomy with no fusion are: moderate central stenosis in elderly patients with unilateral symptoms; lateral stenosis only on one side; and unilateral additional pathology, such as a synovial cyst. Patients with moderate or severe olisthesis, vertebral hypermobility even of mild degree, and/or severe central stenosis and chronic back pain should undergo decompression and fusion. The association of an arthrodesis allows decompression of the neural structures as widely as necessary.

Posterolateral instrumented fusion, using pedicle screw fixation, is the most common procedure, that can be done at multiple level when olisthesis is present at more than one level. In both cases it requires no, or a short, postoperative immobilization Posterolateral fusion may be replaced by PLIF. This procedure, associated with pedicle screw instrumentation, gives excellent results and a high rate of solid fusion. The devices inserted in the disc space are normally represented by cages filled with bone chips. An alternative are the use of blocks of porous tantalum (hedrocel), the stiffness of which is very similar to that of subchondral bone. We are using blocks of hedrocel since 3 years with excellent results in terms of intersomatic fusion. In 20 cases followed for at least 2 years we never observed mobilization of the implant or loosening of the pedicle screws, and we almost consistently found a tight union between the implant and the adjacent vertebrae.

Introduction A wide range of stress-shielding phenomena following THA have been described in the past 20 years. Bone densitometry (DXA) stars as a golden standard in evaluating bone stock and bone density redistribution after total hip replacement.

In this study, DXA scan was employed to evaluate and compare the behaviour of different femoral components including a recently developed stemless implant which features complete stress transfer over the proximal femur.

Methodology A total of 120 patients, operated with six different femoral implants, were included in the present study. Five of these stems are widely commercially available (ABG, CFP, IPS, Mayo, Zweymueller) and present different patterns of stress distribution. The sixth is a custom made implant and features a pronounced lateral flare and complete femoral neck preservation. Rationale of this design is to obtain full load transfer on the proximal femur.

Average interval between the operation and the DXA exam was 3 years, each group included 20 patients. Bone mineral density was measured by DXA in the seven Gruen femoral regions (ROI), using the software metal removal (Hologic QDR 4500 W, MA-USA).

Results Differences in bone density were found in each group as well as between different groups. Significant differences (p< 0.001) were found between the stemless implant and the other five groups in zone I, IV and VII.

CFP, IPS and ABG groups showed decreased bone density in ROI I, while Mayo, IPS, ABG and Zweym-ueller were osteopenic in ROI VII. An increased bone density in ROI IV was found in Zweymueller, Mayo, ABG and IPS groups.

Conclusion Our data suggest that a conservative stemless implant with complete proximal load transfer, produces a homogeneous and more physiologic redistribution of bone density, allowing maintenance of proximal periprosthetic bone stock.

We appraised whether deformity of the inferior limbs, routinely treated with external fixation (EF), can be corrected when synthesis with locked intramedullary nails is associated with the synthesis and what the indications are.

In all, 24 patients with a deformity of the inferior limbs treated between 1997 and 2003 were included in the study and divided into two groups: (1) patients with external fixation, average 23 years, deformity axial 20° (9–28°); and (2) patients with osteotomy and interlocked nailing. average 35 years, deformity axial 16° (10–25°). The indications for treatment with interlocked nail were set according to the following criteria: (a) possibility to correct the deformity with only restoration of the anatomical axis without necessity of lengthening; (b) previous use of EF; (c) EF refused by the patient, and (d) physeal closure.

In both groups complete correction of the deformity was achieved. In the group of patients treated with EF the time of consolidation was on average 5.5 months (range 4–8 months). In this group the time of consolidation proportionally increased to time required to effect a bone lengthening.

In the group of patients treated with osteotomy and nailing the times of consolidation were different with respect to age, to the side and the type of osteotomy and to the type of deformity. The time of consolidation was 7 months (range 3–12 months). The most rapid consolidation corresponds to the congenital deformities treated with oblique osteotomy.

Correction of deformities by osteotomy and interlocked nail introduces the advantage of not limiting joints and immediate correction of the angular and rotatory deformity. The indication for this technique is that there is no residual hypometry. In this case the treatment of choice is corticotomy and external fixation.

Since several spinal conditions are currently treated with spinal fusion, alternatives to autogenous bone graft in spinal surgery have been under study for many years. Results have shown that, compared to other non.-spinal conditions, such as filling bone cavities, spinal fusion, in particular posterolateral fusion, is much more challenging due to the reduced area of the graft bed. As a result, most of the bone substitutes are still under investigation and their effectiveness in the clinical setting has yet to be demonstrated.

In recent years the authors analysed several bone graft substitutes using an animal model which has been widely used in experimental spinal fusion. In particular, porous ceramics have been used alone or with osteoin-ductive material such as fresh bone marrow or cultured mesenchymal stem cells. The results of these studies have shown that with ceramic alone a percentage of solid fusion similar to that with autogenous bone graft cannot be achieved. However, compared to the latter, more favorable results have been obtained when ceramics are loaded with mesenchymal stem cells. The addition of fresh bone marrow to ceramics also increases the fusion rates; however, in this case new bone formation was mainly found in the peripheral portions of the graft and to a lesser extent than when cultured mesenchymal stem cells were used.

Aims: Most of the orthopaedic literature on os acromiale (OA) is focused on corresponding clinical implication, such as impingement syndrome and rotator cuff tear; whilst, although it is present in 8% of subjects, scarce information is reported on the causes that may predispose to it. Our aim is to investigate whether the origin of OA is related to position of AC joint. Methods: The acromions of 211 volunteers (control group) and 33 subjects, respectively, without or with OA have been radiographically (axillary view) classiþed in accordance to the Edelson and Taitzñ method. The latter distinguishes the acromion in three types on the basis of the distance between the anterior aspect of the acromion and AC joint. Out of 33 subjects with os acromiale, 11 were shoulder painless. We have compared among them the frequencies of the types of acromion observed in the two investigated cohorts. Results: Half (52.1%) of the acromions of the control group had the articular facet for the AC joint on the acromion tip whilst in 45.4% facet was tip distally located. On the other hand, out of 33 subjects with OA, 18.1% and 81.1% had, respectively, AC joint lying on or distally to the acromion tip. Conclusions: Our data suggest that the longer is the distance of AC joint from the anterior edge of the acromion, the higher is the possibility that an OA origin.

Aims: We studied the prevalence of calciþc tendinopathy in asymptomatic subjects and the relationship between calciþc deposits and the anatomopathological characteristic of coracoacromial arch. Methods: 222 right-handed volunteers underwent x-ray examination of the right shoulder. We measured the acromiohumeral distance (AHD) and evaluated the acromion shape and the degenerative changes of the GH and AC joints. We measured the size of the deposits and classiþed the calciþcations based on their location, shape and neatness. The subjects with deposits were clinically evaluated and underwent a second x-ray study after 14 months. Results: 11 subjects (5%) had calciþcation. The latter was in the substance of supraspinatus in 5(mean age 45 yrs) and at cuff insertion in 6 (66 yrs). The deposits measured 0.7±0.3cm (avg). There were 3 linear and 2 beanlike intratendinous calciþcations and 5 linear and 1 beanlike deposits at tendon insertion. Calciþcations had well-deþned margins. AHD, acromion shape, arthritic of the GH or AC joint were unrelated to the presence of calciþcations. No subject showed evidence of cuff tear. Intratendinous deposit decreased in size in 2 cases and disappeared in 1. Conclusions: 5% of asymptomatic subjects have calciþcations. Calciþcations are always small and well-deþned. Morphology and changes of the cora-coacromial arch or the GH or AC joint donñt inßuence the deposition of calcium. Our study suggests that calciþcations may decrease in size or disappear without completion of Uhthoffñs cycle.