The use of implant biomaterials for prosthetic reconstructive surgery and osteosynthesis is consolidated in the orthopaedic field, improving the quality of life of patients and allowing for healthy and better ageing. However, there is the lack of advanced innovative methods to investigate the potentialities of smart biomaterials, particularly for the study of local effects of implant and osteointegration. Despite the complex process of osseointegration is difficult to recreate in vitro, the growing challenges in developing alternative models require to set-up and validate new approaches. Aim of the present study is to evaluate an advanced in vitro tissue culture model of osteointegration of titanium implants in human trabecular bone. Cubic samples (1.5×1.5 cm) of trabecular bone were harvested as waste material from hip arthroplasty surgery (CE AVEC 829/2019/Sper/IOR); cylindrical defects (2 mm Ø, 6 mm length) were created, and tissue specimens assigned to the following groups: 1) empty defects- CTR-; 2) defects implanted with a cytotoxic copper pin (Merck cod. 326429)- CTR+; 3) defects implanted with standard titanium pins of 6 µm-rough (ZARE S.r.l) -Ti6. Tissue specimens were cultured in mini rotating bioreactors in standard conditions, weekly assessing viability. At the 8-week-timepoint, immunoenzymatic, microtomographic, histological and histomorphometric analyses were performed. The model was able to simulate the effects of implantation of the materials, showing a drop in viability in CTR+, differently from Ti6 which appears to have a trophic effect on the bone. MicroCT and histological analysis supported the results, with lower BV/TV and Tb.Th values observed in CTR- compared to CTR+ and Ti6 and signs of matrix and bone deposition at the implant site. The collected data suggest the reliability of the tested model which can recreate the osseointegration process in vitro and can therefore be used for preliminary evaluations to reduce and refine in vivo preclinical models.

Acknowledgment: This work was supported by Emilia-Romagna Region for the project “Sviluppo di modelli biologici in vitro ed in silico per la valutazione e predizione dell'osteointegrazione di dispositivi medici da impianto nel tessuto osseo”

Paediatric musculoskeletal (MSK) disorders often produce severe limb deformities, that may require surgical correction. This may be challenging, especially in case of multiplanar, multifocal and/or multilevel deformities. The increasing implementation of novel technologies, such as virtual surgical planning (VSP), computer aided surgical simulation (CASS) and 3D-printing is rapidly gaining traction for a range of surgical applications in paediatric orthopaedics, allowing for extreme personalization and accuracy of the correction, by also reducing operative times and complications. However, prompt availability and accessible costs of this technology remain a concern. Here, we report our experience using an in-hospital low-cost desk workstation for VSP and rapid prototyping in the field of paediatric orthopaedic surgery.

From April 2018 to September 2022 20 children presenting with congenital or post-traumatic deformities of the limbs requiring corrective osteotomies were included in the study. A conversion procedure was applied to transform the CT scan into a 3D model. The surgery was planned using the 3D generated model. The simulation consisted of a virtual process of correction of the alignment, rotation, lengthening of the bones and choosing the level, shape and direction of the osteotomies. We also simulated and calculated the size and position of hardware and customized massive allografts that were shaped in clean room at the hospital bone bank. Sterilizable 3D models and PSI were printed in high-temperature poly-lactic acid (HTPLA), using a low-cost 3D-printer.

Twenty-three operations in twenty patients were performed by using VSP and CASS. The sites of correction were: leg (9 cases) hip (5 cases) elbow/forearm (5 cases) foot (5 cases) The 3D printed sterilizable models were used in 21 cases while HTPLA-PSI were used in five cases. customized massive bone allografts were implanted in 4 cases. No complications related to the use of 3D printed models or cutting guides within the surgical field were observed. Post-operative good or excellent radiographic correction was achieved in 21 cases.

In conclusion, the application of VSP, CASS and 3D-printing technology can improve the surgical correction of complex limb deformities in children, helping the surgeon to identify the correct landmarks for the osteotomy, to achieve the desired degree of correction, accurately modelling and positioning hardware and bone grafts when required. The implementation of in-hospital low-cost desk workstations for VSP, CASS and 3D-Printing is an effective and cost-advantageous solution for facilitating the use of these technologies in daily clinical and surgical practice.

Summary Statement

Pincer deformities are involved in the genesis of femoro-acetabular impingement (FAI). Radiographic patterns suggestive of pincer deformities are common among general population. Prevalence of the pincer deformities among general population may be overestimated if only plain radiographs are considered.

Introduction

We evaluated the osteogenic potential of a novel biomimetic bone paste (DBSint®), made of a combination of a human demineralized bone matrix (hDBM) and a nano-structured magnesium-enriched hydroxyapatite (Mg-HA), in a standardized clinical model of high tibial osteotomy for genu varus.

INTRODUCTION

Since July 2008 we are experimenting a new cup with iliac screw fixation, developed on the idea of Ring and Mc Minn. Iliac fixation is permitted by a polar screw of large diameter, coated by HA, which allows a compression to bone and a firm primary stability. Moreover it's possible to increase primary stability with further smaller peripherals screws. We present this new cup and report the preliminary results.

The use of monoblock tapered stems has shown very good results in hip revision surgery, particularly in case of severe proximal femur bone deficiency.

However a too valgus neck, a short offset, may result in a high risk of dislocation. In addiction monoblock stems make the control of limb length difficult, and potentially increase the risk of subsidence or intraoperative fracture. Different types of modular tapered stems with distal fixation have been developed to allow a more user-friendly restoration of limb-lenght discrepancy and an indipendent proximal control of offset and anti-retroversion.

We assessed 64 hip revisions performed on 63 patients (mean age 62 years). Indication for treatment was: aseptic loosening (42 cases) septic loosening (18 cases) and periprosthetic fracture (4 cases). According to Paprosky classification, femoral defects were staged as type I (2 cases), type II (20 cases), type IIIA (25 cases) and type IIIB (13 cases); periprosthetic fractures were all type B2 according to the Vancouver classification. In all cases we used a Restoration® Modular (Striker, Orthopaedics) cone-conical uncemented stem implanted by a lateral approach, with a trans-femoral osteotomy in 19 cases. A preventive cerclage cable was used in 10 patients in case of very thin cortex. We used the minimum size stem in most of the cases.

Mean follow-up was 20 months (range 6–36). Short-term complications included hip dislocation (1 case), recurrent infection (1 case), stem subsidence > 5 mm (1 case). Mean Harris Hip Score improved from 43 to 81.9 (t test p< 0.0005), while limb lenght discrepancy improved in 97% of cases with symmetry in 76%.

The use of modular revision stems is an effective alternative in hip revision surgery that ensures good primary stability, while modularity enables the implant to be tailored to the patient, allowing restoration of the limb length and correct muscular balancing.

Replacing a fused or ankylosed hip with a prosthesis has several advantages. It reduces the pain in the lumbar-sacral spine and the ipsilateral knee. It gives a better range of movement and leg length is restored.

In this study we present our experience of 50 cases of total hip arthroplasty in fused or ankylosed hips. Aetio-pathogenesis was rhizomelic spondylitis in 35 cases, sequelae of cox it is in 2, posttraumatic in 4, Ankylosis in 6, and fusion in 3. For clinical assessment we used the Merle D’Aubignè score, and for radiographic evaluation we used the Gruen method of area subdivision

Of the 50 prosthesis implanted, 3 were removed due to aseptic loosening. The other were the radiographically stable after an average follow-up of 12 years. Preoperative clinical scores were: pain (2.9), range of motion (2.5), and walking (2.1). At the latest exam the scores were: pain (5.5), motion (4.6), walking (4.5). Preoperative leg shortening was 3.5 cm, whereas at the latest exam it was 0.9 cm. Lumbalgia decreased notably in 62%.

Total hip arthroplasty may have advantages over fusion on one hand, but on the other it is technically more difficult and gives results that are inferior to common indications. It is therefore important to assess patients (time of fusion, age of patient, residual muscular function) preoperatively to obtain good results.

Girdlestone’s arthroplasty is often used to treat septic loosening of hip prostheses. Although this operation provides goodresults with regards to pain and loosening, it causes instability and in the hip and limb shortening that force the patient to use walking aids.

From 1990 to 1999 we treated ten cases of revisionhip arthroplasty after Girdlestone’s arthroplasty. Girdleston e’sarthroplasty was carried out in all cases due to sepsis in the previousimplant. Preoperatively all patients underwent granulocyte-labeledscintigraphy. For clinical evaluation we used the Merle D’Aubignè score.

From 1990 to 1999 we treated ten cases of revisionhip arthroplasty after Girdlestone’s arthroplasty. Girdleston e’sarthroplasty was carried out in all cases due to sepsis in the previousimplant. Preoperatively all patients underwent granulocyte-labeledscintigraphy. For clinical evaluation we used the Merle D’Aubignè score.

Girdlestone’s arthroplasty is very effective for treating septic loosening of hip prostheses, but it causes severe walking impediment. Revision surgery restores limb length and walking. Patients that undergo this treatment should be checked for residual sepsis, which may jeopardize the operation. Currently we are experimenting with spacers with antibiotics and our initial results are promising.

The uncemented cup with iliac stem ensures immediate primary stability by fixation to the hipbone in acetabular loosening with severe bone defect. Homologous bone grafts contribute to restoring bone stock, which is a fundamental requirement for long lasting implant stability.

From 2002 to 2004 we implanted 23 cups with iliac stems in 22 patients. In 7 cases there was also stem loosening, and so total hip arthroplasty was performed. In 2 patients the defect was grade 2b, in 5 grade 3a, and in 16 grade 3b according to Paprosky. A direct lateral approach was performed in the supine position. Morselized bone grafts were used in all cases by the “impaction grafting” technique, and in 4 cases modelled structural grafts were also employed. Mean follow-up has been 18 months (8–32).

So far we have not had any cases of loosening. At follow-up x-rays showed remodelling of the grafts with integration.

The cup with iliac stem enables primary stability on healthy bone tissue, and protects the grafts form mechanical stimulation, thus allowing them to integrate and restore bone-stock. It also restores the centre of rotation, and provides functional benefits and implant stability.

From January 2003 to December 2004, 160 consecutive intertrochanteric hip fractures has been treated at the Orthopaedic Rizzoli Institute by a new short intra-medullary rod, which can be distally locked, combined with two sliding screws that insert into the femoral neck and head. The rod is an undersized, titan one. It can be inserted percutaneously.

Fractures were classified pre-operatively according to stability and post-operatively according to the type of operative reduction.

The failure rate and post-operative stability were then compared according to the type of fracture and to the quality of operative reduction.

Results indicate that the pre-operative fracture classification is a significant determinant of post-operative stability. The type of operative reduction was not as significant a determinant of post-operative stability, but an anatomical reduction gives better clinical results.

Overall results shows that stable fractures has always healed and only minor complications has been observed. Unstable fractures has a percentage of drawbacks of 1.5% (3 in 160 pts) due to a wrong screw positioning ( 2 proximal and 1 distal ).

Three patients died in the early post-operative period due to cardiac failure.

No intraoperative fracture, no displacement of the fracture site and no “cut out” were observed.

Aim: To assess the effect of lyophilised bone grafts, autologous platelet gel and autologous medullary cells on bone repair processes after tibial osteotomy for genu varum

Methods: Thirty patients, divided into 3 groups by the generation of random sampling numbers, were treated by valgus osteotomy for genu varum with a minimum correction of 8 mm and fixation using a titanium plate (TITAN plate® Citieffe).

The groups were thus divided:

Group 1: lyophilised bone chips.

Group 2: lyophilised bone chips + platelet gel

Group 3: lyophilised bone chips + platelet gel + packed autologous medullary cells (Buffy coat).

At six weeks X-rays, MRI and needle biopsies were carried out. The tissue underwent morphological and microstructural tests.

Results confirmed that the use of platelet gel and packed medullary cells as adjuvant for the lyophilised bone aid bone repair and graft integration. Morphological and morphometric tests showed that at six week the newly formed bone of group 3 had better mechanical properties.

Conclusions: This study shows that the use of platelet gel and packed autologous medullary cells combined with lyophilised bone chips produces a faster and mechanically stronger recovery of bone stock in the treatment of bone defects.

Introduction Total hip arthroplasty in patients affected by major dysplasia poses great surgical difficulties due to insufficient primary acetabulum, small femoral canal, excessive anteversion of the femoral neck, traction on the neurovascular structures, muscular imbalance that is difficult to restore, and marked epiphyseal rising. In this study we present our experience in lowering and arthroplasty in major hip dysplasia, obtained by shortening osteotomy achieved in a single stage, using techniques designed to diminish possible risks.

Materials and methods From 1989 to 2000 we treated 20 patients (27 operations, 7 bilateral) at our institute who were affected by the sequela (lowering of the prosthesis) of Eftekhar Grade-C (11 cases) or Grade-D (16 cases) congenital luxation of the hip. Mean follow-up was 63 months. Clinical results were assessed before and after surgery according to the Merle D’Aubigné method. We also evaluated the presence and degree of Trendelenburg position and the possible use of shoe lifts. The radiographic results of the hip prosthesis were assessed by the Gruen and Dee Lee methods for the stem and cup respectively.

Results The mean preoperative clinical score according to the Merle D’Aubigné classification was 3 ± 1 for pain, 3 ± 1 for walking, and 4 ± 2 for movement. The preoperative Trendelemburg position was very marked in all patients. In 18 cases out of 27 a shoe lift was used with a mean height of 60 mm ± 10. We performed a “Z” osteotomy in 14 cases and an oblique osteotomy in 13 cases. The postoperative mean clinical score was 6 ± 1 for pain, 6 ± 1 for walking, and 5 ± 1 for movement. Postoperative Trendelemburg position was present in 19 cases, and 9 cases out of 27 still used a shoe lift with a mean height of 30 mm ± 10. Movement of the cup and stem was observed at 84 months and 112 months’ follow-up respectively, which required revision surgery.

Conclusions The choice between oblique and Z osteotomy depends on two parameters: the surgeon’s experience and the extent of femoral resection. Z osteotomy may be more difficult to perform technically, but it enables better adaptation of the prosthesis to the femoral segments for resections over 35 mm. No significant differences in time to unite were observed between oblique and Z osteotomies.

Aim Although converting a loosened fixation of the proximal femur into a total hip arthroplasty restores the joint, it is a technically complex operation and often requires steps that are not usually performed in arthroplasty for common diseases. The aim of this study was to assess clinical and radiographic results of 127 total hip arthroplasties due to loosening of proximal femur fixation, performed at our institute.

Materials and methods From 1987 to 2001 we performed 127 total hip arthroplasties (THA) in patients with loosened facture fixation of the proximal femur. Patients treated by endoprosthesis were excluded from this study.

The patients were divided into two groups according to the fracture site. Group 1 included 71 patients with medial fracture, and Group 2 contained 56 patients pertrochanteric or subtrochanteric fracture. All patients were assessed by the Merle d’Aubignè clinical evaluation method. Radiographically, the bone-implant interface was assessed by the presence of radiolucency lines according to the DeLee-Charnley method modified by Martell

Results The mean time lapse between fixation and conversion was 31 months for Group 1 and 10 months for Group 2 patients. In 12 cases of Group 2 bone grafts were used and surgery time was on average 20′ longer than that of Group 1. Furthermore, in Group 2, we had 4 dislocations compared to none in Group 1. In Group 2 long-stem prostheses with diaphyseal conical anchorage were more frequently used, whereas in Group 1 standard prostheses were used in all cases. Patients of Group 2 had a lower clinical score for the three parameters assessed (pain, walking and ROM) than those of Group 1. The final clinical results were also better for Group 1 patients.

Conclusions This study shows how THA in fixation loosening of proximal femur fractures can provide good results. Especially in patients with medial fractures of the femur, since the anatomy is not altered, THA does not pose any particular difficulties and ensures excellent results. In fractures of the trochanteric mass, where non-union or malunion alter markedly the anatomy of the bone segment, the site for the implant, results are certainly inferior However, careful planning of the operation, the use of special prostheses, and bone grafts enable satisfactory results to be achieved in these patients too.

Aim: to assess the effect of lyophilized bone grafts, autologous platelet gel and autologous medullary cells on bone repair processes after tibial osteotomy for genu varum.

Methods: thirty patients, divided into 3 groups by the generation of random sampling numbers, were treated by valgus osteotomy for genu varum with a minimum correction of 8 mm and fixation using a titanium plate (TITAN plateA8 Citieffe).

The groups were thus divided:

Group 1: lyophilized bone chips.

At six weeks X-rays, MRI and needle biopsies were carried out. The tissue underwent morphological and microstructural tests.

Results: preliminary results confirmed that the use of platelet gel and packed medullary cells as adjuvant for the lyophilized bone aid bone repair and graft integration. Morphological and morphometric tests showed that at six week the newly formed bone of group 3 had better mechanical properties.

Conclusions: this study shows that the use of platelet gel and packed autologous medullary cells combined with lyophilized bone chips produces a faster and mechanically stronger recovery of bone stock in the treatment of bone defects.

Introduction: Replacing a fused or ankylosed hip with a prosthesis has several advantages. It reduces the pain in the lumbar-sacral spine and the ipsilateral knee. It gives a better range of movement and leg length is restored.

Methods: In this study we present our experience of 50 cases of total hip arthroplasty in fused or ankylosed hips. Aetiopathogenesis was rhizomelic spondylitis in 35 cases, sequelae of coxitis in 2, posttraumatic in 4, Ankylosis in 6, and fusion in 3. For clinical assessment we used the Merle D’Aubignè score, and for radiographic evaluation we used the Gruen method of area subdivision.

Results: Of the 50 prosthesis implanted, 3 were removed due to aseptic loosening. The other were radiographically stable after an average follow-up of 12 years. Preoperative clinical scores were: pain (2.9), range of motion (2.5), and walking (2.1). At the latest exam the scores were: pain (5.5), motion (4.6), walking (4.5). Preoperative leg shortening was 3.5 cm, whereas at the latest exam it was 0.9 cm. Lumbalgia decreased notably in 62%.

Conclusions: Total hip arthroplasty may have advantages over fusion on one hand, but on the other it is technically more difficult and gives results that are inferior to common indications. It is therefore important to assess patients (time of fusion, age of patient, residual muscular function) preoperatively to obtain good results