Aims

Disorders of bone integrity carry a high global disease burden, frequently requiring intervention, but there is a paucity of methods capable of noninvasive real-time assessment. Here we show that miniaturized handheld near-infrared spectroscopy (NIRS) scans, operated via a smartphone, can assess structural human bone properties in under three seconds.

Aim. The primary endpoint of this study is to characterize the progression of bone defects at the femoral and tibial side in patients who sustained PJI of the knee that underwent two-stage revision with spacer implantation. In addition, we want to analyze the differences between functional moulded and hand-made spacers. Methods. A retrospective analysis of patients that underwent two-stage revision due to PJI of the knee between January 2014 and December 2021 at our institution. Diagnosis of infection was based on the criteria of the Muscoloskeletal Infection Society. The bone defect evaluation was performed intraoperatively based on the AORI classification. The basal evaluation was performed at the time the resection arthroplasty and spacer implantation surgery. The final evaluation was performed at the second-stage surgery, at the time of spacer removal and revision implant positioning. The differences between groups were characterized by using T-test student for continuous variables, and by using chi-square for categorical variables. A p-value < 0.05 was defined as significant. Results. Complete data of 37 two-stage TKAs revision were included in the study. An articulating moulded functional spacer was used in 14 (35.9%) cases, while a hand-made spacer was used in 23 (58.9%) cases. The average length of interval period (excluding the time for patients that retained the spacer) was 146.6 days. A bone defects progression based on the AORI classification was documented in 24 cases at the femoral side (61.6%), a bone defect progression was documented in 17 cases at the tibial side (43.6%), and a bone defect at both sides was documented in 13 cases (33.3%). A statistically significant greater bone defect progression at the tibial side was observed when hand-made spacers were used. A complication during the interval period was reported in five cases (12.8%) and postoperative complication was reported in 9 cases (23.1%). Conclusions. When comparing patients in which a functional articulating spacer was used, with patients in which static spacer was used, we reported a statistically significant reduced bone defect progression during the interval period at the femoral side only when moulded spacers were used. We observed a higher incidence of bone defect progression also at the tibial and both sides when hand-made spacers were used. This is the first study that documented the bone defect progression during two-stage revision of the knee, the results observed in this study are very encouraging

Aims

Focal knee arthroplasty is an attractive alternative to knee arthroplasty for young patients because it allows preservation of a large amount of bone for potential revisions. However, the mechanical behaviour of cartilage has not yet been investigated because it is challenging to evaluate in vivo contact areas, pressure, and deformations from metal implants. Therefore, this study aimed to determine the contact pressure in the tibiofemoral joint with a focal knee arthroplasty using a finite element model.

Aims. Assessment of bone health is a multifaceted clinical process, incorporating biochemical and diagnostic tests that should be accurate and reproducible. Dual-energy X-ray absorptiometry (DXA) is the reference standard for evaluation of bone mineral density, but has known limitations. Alternatives include quantitative CT (q-CT), MRI, and peripheral quantitative ultrasound (QUS). Radiofrequency echographic multispectrometry (REMS) is a new generation of ultrasound technology used for the assessment of bone mineral density (BMD) at axial sites that is as accurate as quality-assured DXA scans. It also provides an assessment of the quality of bone architecture. This will be of direct value and significance to orthopaedic surgeons when planning surgical procedures, including fracture fixation and surgery of the hip and spine, since BMD alone is a poor predictor of fracture risk. Methods. The various other fixed-site technologies such as high-resolution peripheral q-CT (HR-pQCT) and MRI offer no further significant prognostic advantages in terms of assessing bone structure and BMD to predict fracture risk. QUS was the only widely adopted non-fixed imaging option for bone health assessment, but it is not considered adequately accurate to provide a quantitative assessment of BMD or provide a prediction of fracture risk. In contrast, REMS has a robust evidence base that demonstrates its equivalence to DXA in determining BMD at axial sites. Fracture prediction using REMS, combining the output of fragility information and BMD, has been established as more accurate than when using BMD alone. Conclusion. The practice parameters described in this protocol provide a framework for clinicians who provide REMS services that will, to the greatest possible extent, ensure the most accurate assessment possible from this diagnostic technology. Cite this article: Bone Jt Open 2025;6(3):291–297

Aims

To investigate the effects of senescent osteocytes on bone homeostasis in the progress of age-related osteoporosis and explore the underlying mechanism.

Introduction and Objective. The patients with a total hip arthroplasty is growing in world manly in Europe and USA, and this solution present a high success at 10years in several orthopaedic registers. The application of total press-fit hip fixation presents the most used solution, but presents some failures associated to the acetabular component fixation, associated to the load transfer and bone loss at long term. The aim of this work is to investigate the influence of different acetabular bone loss in the strain distribution in iliac bone. To evaluate implant fixation, an experimental study was performed using acetabular press-fit component simulating different acetabular bone loss and measuring the strain distribution. Materials and Methods. The experimental samples developed was based in an iliac bone model of Sawbones supplier and a acetabular component Titanium (Stryker) in a condition press-fit fixation and was implanted according surgical procedure with 45º inclination angle and 20º in the anteversion angle. Were developed five models with same initial bone, one with intact condition simulating the cartilage between bones and four with different bone loss around the acetabular component. These four models representing the evolution of bone support of acetabular components presented in the literature. The evolution of bone loss was imposed with a CAD CAM process in same iliac bone model. The models were instrumented with 5 rosettes in critical region at the cortical bone to measure the strain evolution along the process. Results. The results of strain gauges present the influence of acetabular component implantation, reducing the bone strains and presented the effect of the strain shielding. The acetabular component works as a shield in the load transfer. The critical region is the posterior region with highest principal strains and the strain effect was observed with different bone loss around acetabular component. The maximum value of principal strain was observed in the intact condition in the anterior region, with 950μ∊. In the posterior superior region, the effect of bone loss is more important presenting a reduction of 500% in the strains. The effect of bone loss is presented in the strains induced with acetabular implantation, in the first step of implantation the maximum strain was 950μ∊ and in the last model the value was 50μ∊, indicating lower press-fit fixation. Conclusions. The models developed allows study the effect of bone loss and acetabular implant fixation in the load transfer at the hip articulation. The results presented a critical region as the anterior-superior and the effect of strain shielding was observed in comparison with intact articulation. The results of press-fit fixation present a reduction of implant stability along bone loss. The process of bone fixation developed present some limitation associated to the bone adhesion in the interface, not considered. Acknowledgement. This work was supported by POCI-01-0145-FEDER-032486,– FCT, by the FEDER, with COMPETE2020 - (POCI), FCT/M

Aims

One of the main causes of tibial revision surgery for total knee arthroplasty is aseptic loosening. Therefore, stable fixation between the tibial component and the cement, and between the tibial component and the bone, is essential. A factor that could influence the implant stability is the implant design, with its different variations. In an existing implant system, the tibial component was modified by adding cement pockets. The aim of this experimental in vitro study was to investigate whether additional cement pockets on the underside of the tibial component could improve implant stability. The relative motion between implant and bone, the maximum pull-out force, the tibial cement mantle, and a possible path from the bone marrow to the metal-cement interface were determined.

Surgical treatment of fragility sacrum fractures with percutaneous sacroiliac (SI) screw fixation is associated with high failure rates in terms of screw loosening, cut-through and turn-out. The latter is a common cause for complications, being detected in up to 20% of the patients. The aim of this study was to develop a new screw-in-screw concept and prototype implant for fragility sacrum fracture fixation and test it biomechanically versus transsacral and SI screw fixations. Twenty-seven artificial pelves with discontinued symphysis and a vertical osteotomy in zone 1 after Denis were assigned to three groups (n = 9) for implantation of their right sites with either an SI screw, the new screw-in-screw implant, or a transsacral screw. All specimens were biomechanically tested to failure in upright position with the right ilium constrained. Validated setup and test protocol were used for complex axial and torsional loading, applied through the S1 vertebral body. Interfragmentary movements were captured via optical motion tracking. Screw motions in the bone were evaluated by means of triggered anteroposterior X-rays. Interfragmentary movements and implant motions in terms of pull-out, cut-through, tilt, and turn-out were significantly higher for SI screw fixation compared to both transsacral screw and screw-in-screw fixations. In addition, transsacral screw and screw-in-screw fixations revealed similar construct stability. Moreover, screw-in-screw fixation successfully prevented turn-out of the implant, that remained at 0° rotation around the nominal screw axis unexceptionally during testing. From biomechanical perspective, fragility sacrum fracture fixation with the new screw-in-screw implant prototype provides higher stability than with the use of one SI screw, being able to successfully prevent turn-out. Moreover, it combines the higher stability of transsacral screw fixation with the less risky operational procedure of SI screw fixation and can be considered as their alternative treatment option

Aims

Accumulated evidence indicates that local cell origins may ingrain differences in the phenotypic activity of human osteoblasts. We hypothesized that these differences may also exist in osteoblasts harvested from the same bone type at periarticular sites, including those adjacent to the fixation sites for total joint implant components.

Autologous bone grafting is a standard procedure for the clinical repair of skeletal defects, and good results have been obtained. Autologous vascularized bone grafting is currently the procedure of choice because of high osteogenic potential and resistance against reabsorption. Disadvantages of this procedure include limited availability of donor sites, clinical difficulty in handling, and a failure rate exceeding 10%. Allografts are often used for massive bone loss, but since only the marginal portion is newly vascularized after the implantation non healing fractures are often reported, along with a graft reabsorption. To overcome these problems, some studies in literature tried to conjugate bone graft and vascular supply, with encouraging results. On the other side, several studies in literature reported the ability of bone marrow derived cells to promote neo-vascularization. In fact, bone marrow contains not only hematopoietic stem cells (HSCs) and MSCs as a source for regenerating tissues but also accessory cells that support angiogenesis and vasculogenesis by producing several growth factors. In this scenario a new procedure was developed, consisting in an allogenic bone graft transplantation in a critical size defect in rabbit radius, plus a deviation at its inside of the median artery and vein with a supplement of autologous bone marrow concentrate on a collagen scaffold. Twenty-four New Zealand male white rabbits (2500–3000 g) were divided into 2 groups, each consisting of 12 animals. Surgeries were performed as follow:. −. Group 1 (#12): allogenic bone graft (left radius) / allogenic bone graft + vascular pedicle + autologous bone marrow concentrate (right radius). −. Group 2 (#12): sham operated (left radius)/ allogenic bone graft + vascular pedicle (right radius). For each group, 3 experimental time: 8, 4 and 2 weeks (4 animals for each time). The bone used as graft was previously collected from an uncorrelated study. An in vitro evaluation of bone marrow concentrate was performed in all cases, and at the time of sacrifice histological and histomorphometrical assessment were performed with immunohistochemical assays for VEGF, CD31 e CD146 to highlight the presence of vessels and endothelial cells. Micro-CT Analysis with quantitative bone evaluation was performed in all cases. The bone marrow concentrate showed a marked capability to differentiate into osteogenic, chondrogenic and agipogenic lineages. No complications such as infection or intolerance to the procedure were reported. The bone grafts showed only a partial integration, mainly at the extremities in the group with vascular and bone marrow concentrate supplement, with a good and healthy residual bone. immunohistochemistry showed an interesting higher VEGF expression in the same group. Micro CT analysis showed a higher remodeling activities in the groups treated with vascular supplement, with an area of integration at the extremities increasing with the extension of the sacrifice time. The present study suggests that the vascular and marrow cells supplement may positively influence the neoangiogenesis and the neovascularization of the homologous bone graft. A longer time of follow up and improvement of the surgical technique are required to validate the procedure

Purpose. It is generally accepted that the cement mantle surrounding the femoral component of a cemented total hip arthroplasty (THA) should be complete without any defects, and of at least 2 mm in thickness. Radiographic evaluation is the basis for assessment of the cement mantle. The adequacy of radiographic interpretation is subject to debate. Poor interobserver and intraobserver reproducibility of radiographic cement mantle assessment has been reported. In this study, 3D template software was used that allow anatomical measurements and analysis of three-dimensional digital femura geometry based on CT scans. The purpose of this study is to analyze the three-dimensional cement mantle thickness of cemented hip stem. Materials and Methods. 52 hips that underwent THA with Exeter stem (Stryker Orthopaedics, Mahwah, NJ) were enrolled in this study. All surgeries were performed by a single surgeon. There were 49 hips in 49 women and 3 hips in 3 men. The average age at surgery was 73 years (range, 60–88 years). The etiology of the hip lesions were osteoarthrosis in 49, rheumatoid arthritis in 3, and osteonecrosis of the femoral head in 1. For preoperative and postoperative evaluation, a CT scan of the pelvis and knee joint was obtained and was transferred to 3D template software (Zed hip, Lexi, Tokyo, Japan). We evaluated the alignment for stem anteversion/valgus/anterior tilt angles and the contact of the cortical bone with the cement mantle was evaluated. Results. Concerning the alignment of the stems, variability was observed in the anteversion; however, the stems were inserted in an almost neutral position in varus-valgus and extension-flexion. The 3D contact of the stems with a cement mantle of 2 mm added with the cortical bone was evaluated, and it could be broadly classified into three patterns: cases in which the cortical bone was not reamed in the range of 2 mm from the stem, those in which the distal medial part was partially reamed, and cases in which the distal anterior and medial parts of the cortical bone were reamed in a relatively wide range. In this study, there were 17 patients with no reaming, 32 patients with partial reaming, and 3 patients with a relatively large range of reaming. Discussion and Conclusion. Oversizing of the stem associated with incomplete cement mantles has been suggested to account for early femoral component loosening. In this study, 3 patients whose cortical bone was reamed in a relatively wide range and who had a risk of partial thinning of the cement mantle as a result were observed. The effect of reaming of the cortical bone on the clinical results is still unknown; however, a careful follow-up in the future may be required

Introduction: Treatment of defected pseudoarthrosis tibia remains controversial due to bone loss with/without infection arises from previous interventions. In the present study we evaluated the results of acute shortening and distraction osteogenesis in the treatment of tibia pseudoarthrosis with bone loss. Material and Methods: Eleven patients were treated with acute shortening and distraction osteogenesis. Mean age and bone loss was 27.5 years (range 10–44) and 8.9 cm (range 3.5–12) respectively. 7 of eleven patients is infected pseudoarthrosis. Enfected patients were type 4A according to Chierny-Mader classification. The 4 of infected patients were treated with two staged procedure. In the first stage antibiotic (teicoplanin) impregnated polymethylmetacrilate beads were placed to the space occurred as a result of excision of sclerotic bone segment and fixation was performed by external fixator or braces. Second stage composed of acute compression (shortening) and distraction osteogenesis. Other 3 infected and noninfected patients were treated with resection, acute shortening and distraction osteogenesis in one stage. In six cases docking site were grafted with autografts. Defects greater than 4 cm were gradually shortened 2mm/day in addition to acute shortening. Limb length inequality was solved with lengthening from proximal tibial corticotomy and achieving union of both sites about the same time. Results: Mean follow up, external fixator time and external fixator index was 48.3 months (21–80), 8.9 months (6–13) and 1,3 month/cm respectively. results were evaluated according to Paley’s bone and functional evaluation scoring. Eleven patient revealed excellent results with regard to bone evaluation and 10 patient revealed excellent and 1 patient revealed good results in terms of functional evaluation. In one patient fracture at the pseudoartrosis site occurred due to new trauma after removal of the fixator which was treated with circular external fixator. In the another patient, the lengthening regenerate side was low quality bone which need intra-medullary fixation and grafted with autograft. Conclusion: Acute shortening and distraction osteogenesis is a safe and successful procedure in the treatment of defected tibia pseudoarthrosis and is alternative to other treatments. Acute shortening and distraction osteogenesis was found to be successful and safe with regard to functional results in the treatment of defected tibia pseudoarthrosis. Besides we suggest it as an alternative due to lower rate of complications and less external fix-ator time compared to other Methods:

Backgrounds. Most of in vivo kinematic studies of total knee arthroplasty (TKA) have reported on varus knee. TKA for the valgus knee deformity is a surgical challenge. The purposes of the current study are to analyze the in vivo kinematic motion and to compare kinematic patterns between weight-bearing (WB) and non-weight-bearing (NWB) knee flexion in posterior-stabilized (PS) fixed-bearing TKA with pre-operative valgus deformity. Methods. A total of sixteen valgus knees in 12 cases that underwent TKA with Scorpio NRG PS knee prosthesis operated by modified gap balancing technique were evaluated. The mean preoperative femorotibial angle (FTA) was 156°±4.2°. During the surgery, distal femur and proximal tibia was cut perpendicular to the mechanical axis of each bone. After excision of the menisci and cruciate ligaments, balancer (Stryker joint dependent kinematics balancer) was inserted into the gap between both bones for evaluation of extension gap. Lateral release was performed in extension. Iliotibial bundle (ITB) was released from Gerdy tubercle then posterolateral capsule was released at the level of the proximal tibial cut surface. If still unbalanced, pie-crust ITB from inside-out was added at 1 cm above joint line until an even lateral and medial gap had been achieved. Flexion gap balance was obtained predominantly by the bone cut of the posterior femoral condyle. Good postoperative stability in extension and flexion was confirmed by stress roentgenogram and axial radiography of the distal femur. We evaluated the in vivo kinematics of the knee using fluoroscopy and femorotibial translation relative to the tibial tray using a 2-dimentional to 3-dimensional registration technique. Results. The average flexion angle was 111.3°±7.5° in weight-bearing and 114.9°±8.4° in non-weight-bearing. The femoral component demonstrated a mean external rotation of 5.9°±5.8° in weight-bearing and 7.4°±5.2° in non-weight-bearing (Fig.1). In weight-bearing, the femoral component showed medial pivot pattern from 0° to midflexion and a bicondylar rollback pattern from midflexion to full flexion (Fig2). Medial condyle moved similarly in non-weight-bearing condition and in weight-bearing condition. Lateral condyle moved posterior in slightly earlier angle during weight-bearing condition than during non-weight-bearing condition (Fig.3). Discussion. Numerous kinematic analyses of a normal knee have demonstrated greater posterior motion of the lateral femoral condyle relative to the medial condyle, leading to a mean external rotation and a bicondylar rollback motion with progressive knee flexion. A kinematic analysis of valgus knee was reported to show a different kinematic pattern from a physiological knee motion. Many valgus knees showed paradoxical anterior translation from extension to mid-flexion and greater posterior translation in the medial condyle than in the lateral condyle. Kitagawa et al. reported that this non-physiologic pattern wasn't completely restored after TKA using medial pivot knee system. In the present study, we showed kinematic patterns of the TKA performed on the valgus knee to be similar to the normal knee for the first time, even though the magnitude of external rotation was small. Conclusions. We conclude that the medial pivot pattern followed by posterior rollback motion can be obtained in TKA with modified gap balancing technique for the preoperative valgus deformity

In cases of poor bone quality intraoperative torque measurement might be an alternative to preoperative dual energy x-ray absorptiometry (DXA) to assess bone quality in Total Hip Arthroplasty (THA). 14 paired fresh frozen human femurs were included for trabecular peak torque measurement. We evaluated an existing intraoperative torque measurement method to assess bone quality and bone strength. We modified the approach to use this method in total hip arthroplasty (THA), which has not been published before. Since there are several approaches used in THA to exposure the hip joint, we decided to prefer the measurement in the femoral head which allows every surgeon to perform this measurement. Here a 6.5 × 23 mm blade was inserted into the proximal femur without harming the lateral cortical bone (figure 1). Further tests of the proximal femur evaluated the results of this new method: DXA, micro-computed tomography (μCT) and biomechanical load tests. Basic statistical analyses and multiple regressions were done. In the femoral head mean trabecular peak torque was 4.38 ± 1.86 Nm. These values showed a strong correlation with the values of the DXA, the μCT and the biomechanical load test. In comparison to the bone mineral density captured by DXA, the results of the intraoperative torque measurement showed a superior correlation with high sensitive bone quality evaluating methods (mechanical load tests and micro-computed tomography). Hence, the use of this intraoperative torque measurement seems to be more accurate in evaluating bone strength and bone quality than DXA during THA. The torque measurement provides sensitive information about the bone strength, which may affect the choice of implant in cases of poor bone stock and osteoporosis. In clinical use the surgeon may alter the prosthesis if the device indicates poor bone quality. Furthermore, we assume that the disadvantages associated with DXA scans like radiation exposure or errors caused by potential extraosteal sclerosis and interindividual soft-tissue artifacts could be excluded

Great diffusion of hip prosthetic surgery, in relatively-young patients too, generates as consequence an increase in prosthesis failures associated with limited or massive bone losses, making revision surgery mandatory, even in most advanced degrees of osteolysis. In best surgery strategy planning are essential: - evaluation of osteolysis degree with standard x-Rays; - evaluation of periprosthetic bone turn-over with scintigraphy (both a specific as they give merely qualitative evaluations of bone remodeling); – quantitative evaluation of periprosthetic bone mineral density with periprosthetic mineralometry (D.E.X.A.). Data obtained with these methods allow more accurate decisions, during the pre-operative phase, regarding the most indicated implant for revision surgery: mid or long-stem, with or without omoplastic transplants, with or without materials promoting bone rehabitation. In any case, the surgeon must have all possible solutions in order to eventually change the operative plan during surgical act. Following qualitative and quantitative periprosthetic bone evaluations, we use to classify stem and cup mobilizations with Italian Group for Revision (GIR) classification. According to GIR classification, our actual trends in the choice of revision prostheses, in the most advanced degrees of complex mobilizations of stem and cup, are the following: - GIR 3 (Enlargement of the femoral shaft with thinning of cortical bone and loosing of 2 or more walls; loosening and acetabular deformation with losing of one ore more columns and the bottom). In this degree we prefer a long-stem concept straight prosthesis; this prosthesis allows an immediately more stable implant, due to optimized length, in opposition to rotation forces and assuring force transfer in both proximal and distal direction. When osteolysis is wider, it was necessary a strategy change, searching a more distal locking of the implant, according to Wagner’s criteria. The SL Wagner’s prosthesis restores cohesion with the reabsorbed bone surface, generating a relative stability in the immediate post-op period; in the following 2 months, an intense bone apposition, which brings to a progressive filling of bone losses, takes place. For this purpose, it is not indicated, apart from surgical way used, cutting the muscle insertions around the thinned wall. This revision prosthesis is fixed without the use of cement due to the distal blocking, guaranteed by his conical shape; the stem is straight and it is not fit to the natural front-bending of femoral shaft. For this last explained reason, we follow these guidelines, improving our results, using a cementless anatomic modular stem: with this kind of implant design, that preserves cortical bone of femoral shaft from stress shielding, and the extremely wide (XX combination) choice of head and neck components, we are now able to regain as well as possible, the correct offset and center of rotation. For the acetabular loosening, we use to implant oval cups, that naturally fit the acetabular lesion, with or without bone grafts impaction in bone loss areas.- GIR 4 (Massive proximal bone loss all around the shaft; massive peri-acetabular loss). In the past we implanted wide-resection cemented (Muller) or non cemented (Kotz) prosthesis, originally designed for onchologic patients, to treat complete femoral osteolysis. The wide resection uncemented prosthesis, after follow up, supports the Wagner’s theory of distal support, because in spite of an almost complete bone sacrifice, there is an attempt of periprosthetic corticalization by the femoral bone. Since some years we implant even in this cases a modular distally-anatomic revision prosthesis, this type of prosthesis, thanks to his proximal component, provides a relative primary metaphyseal support, that improves global stability of implant. In massive peri-acetabular loss we prefer the use of oval components with peripheral supports and obturatory hook, with bone graft impaction. Only as “extrema ratio” we choose for the implant a McMinn stemmed cup. From these guidelines, integrated with clinical observation at mid range follow-up, appears clerarly that cementless prosthesis in hip revision surgery, even in most advanced degrees of osteolysis, are really able to guarantee good results for the patient. These patients, previously implanted with hip prosthesis, have intrinsic limitations of hip joint ROM, sometimes associated with muscular impairments; therefore it’s rarely possible to bring back the hip to an optimal degree of function, especially if compared with a normal joint. The goodness of long-term results must be therefore evaluated in relation to patient’s conditions before the operation itself, especially according to bone conditions regarding osteointegration of prosthesis. If follow up of patient is constant, allowing to program with good timing the revision surgery, if necessary, the use of cementless prostheses is a very powerful (nevertheless conservative) instrument for good functional recovery of these patients

Objectives

The objective of this study was to investigate the therapeutic effect of peripheral blood mononuclear cells (PBMNCs) treated with quality and quantity control culture (QQ-culture) to expand and fortify angiogenic cells on the acceleration of fracture healing.

Summary of background data: Lumbar interbody arthrodesis can be achieved by using autograft or allograft bone. One of the disadvantages of using autograft bone graft is complications related to the iliac crest donor site. Another option is using an allograft bone (ex.-femoral head from bone bank). There are few reports of using allograft bone for instrumented lumbar spinal fusion. Methods: Fifteen patients were treated at our institution by lumbar fusion in various indications. We used allograft bone and evaluated their outcome for an average period of 3 years. The recovery rate, complications and radiographic findings were evaluated. Results: Good radiographic and clinical results were achieved by using allograft bone graft. No complications were detected. Conclusions: The clinical and radiographic results of Allograft bone graft, for lumbar spine arthrodesis, are impressive. One of the advantages of this method, comparing to an autograft is avoiding any donor site complications

Purpose: Porous tantalum has been shown to be very effective in achieving bone ingrowth. However, in some circumstances, bone quality or quantity is insufficient to allow adequate bone ingrowth. We hypothesized that the addition of alendronate to porous tantalum would enhance the ability of porous tantalum to achieve bone ingrowth in these challenging situations, such as when a gap exists between the implant and bone. We evaluated the effect of alendronate coated porous tantalum on new bone formation in an animal model incorporating a gap between implant and bone. Method: Thirty-six cylindrical porous tantalum implants were bilaterally implanted into the distal femur of 18 rabbits for 4 weeks. There were 3 groups of implants inserted; a control group of porous tantalum with no coatings, porous tantalum with micro-porous calcium phosphate coating, and porous tantalum coated with micro-porous calcium phosphate and alendronate. Subcutaneous fluorescent labeling was used to track new bone formation. Bone formation was analyzed by backscattered electron microscopy and fluorescent microscopy on undecalcified samples. Results: The relative increase in mean volume of gap filling, bone ingrowth and total bone formation was 143% (p< 0.001), 259% (p< 0.001) and 193% (p< 0.001) respectively in the alendronate coated porous tantalum compared with the uncoated porous tantalum controls. The relative increase in the percentage of new bone-implant contact length was increased by 804% on average in the alendronate coated porous tantalum compared with the uncoated tantalum controls. Conclusion: This study demonstrated the significant enhancement of bone-implant gap filling and bone ingrowth which can be achieved by coating porous tantalum with alendronate. It is proposed that, when faced with the clinical problem of revision joint replacement in the face of bone loss (at the hip, knee or elsewhere), the addition of an alendronate-delivery surface coating would enhance biological fixation of the implant and promote the healing of bone defects

Proximal juxta-articular leg fractures are often high-energy injuries, involving the tibial articular surface as well as diaphyseal segments. Young, active people are frequently affected, and optimal reduction, effective stabilization, early function and a rapid return to daily-life are the goals of treatment. These fractures are, as well known, difficult to treat, because of the frequent articular involvement, fragment comminution and extension of the fracture rim: if not adequately treated, they might result in mal-union, non-union, articular stiffness and late arthrosis. Mal-union, both angular and rotational, are, in many cases, very difficult lesions to treat, almost always requiring osteotomies, osteointegration and stable fixation: we present our experience in the treatment of these lesions, with the results obtained in 31 cases treated with a minimum of 1 year of follow-up. The same protocol was used in all patients: direct surgical approach to the lesion, removal of any implanted device, careful débridement of the mal-union site (mainly directed to complete interposed fibrous tissue removal), deformity correction, stable internal fixation and osteointegration, whenever necessary, by autologous or homologous bone. We evaluated all cases in terms of patient satisfaction, deformity correction, bone healing and functional recovery: one major complication occurred (nail failure); delayed skin healing was seen in three patients (one requiring re-operation), and one patient there was rupture of a distal locking screw. In conclusion, this method is effective in the treatment of these lesions

Aims: 1) to create a new and reproducible animal model to produce heterotopic ossification (HO) 2) to be able to exactly quantify the amount of HO using a microCT scan and 3) to prove the hypothesis that COX-2 inhibitors are efficacious in the prevention of HO. Methods: We developed a IACUC-approved Lewis rat model, in which the ventral side of the right femur was scraped to mechanically disrupt the periosteum. By clamping the vastus intermedius ischemic injury to the muscle was produced to enhance HO. Finally homologous bone marrow from a donor rat was placed on the anterior surface of the femur. Half of the study group (8 rats) received chow mixed with a COX-2 inhibitor, while the other half received normal chow. After 6 weeks the animals were sacrificed, the femurs removed and imaged by microCT. Grading of HO was based on the thickness of ectopic bone as evaluated in a blinded fashion by 3 independent observers. Results: All animals developed bilateral HO. Rats treated with COX-2 inhibitors developed significantly less ectopic bone than the control group rats. Conclusions: The results suggest that we have created a very reliable, reproducible model to form ectopic bone in rats. Using the microCT we can precisely quantify the amount of HO. We have been able to show that COX-2 inhibitors significantly decrease the amount of HO formation and are thus a good alternative to non-specific NSAIDs with their potential serious side effects on the gastrointestinal tract and on hemo-stastis