Total disc replacement (TDR) is the gold standard for lumbar degenerative disc disease in selected patient groups. Traditional TDR designs benefit from a wealth of literature and use a polyethylene inlay pseudo-disc between two metal endplates. There is scarce literature for novel monomodular implants that form an artificial construct of woven annulus and central nucleus, providing physiological motion preservation. The aim was to compare the evolving changes to radiological position between monomodular and traditional implants and assess the relationship of migration with bone densitometry. This retrospective series of consecutive patients undergoing TDR under a single surgeon recorded demographics, co-morbidities, previous surgery and clinical outcomes. Measurements of endplate subsidence, lordosis and spondylolisthesis taken from weight-bearing erect x-rays at 0, 3, 6 and 12 months. Radiological outcomes were compared against CT bone densitometry. 33 monomodular and 13 traditional implants. Mean age 40 years. All patients had degenerative disc disease. Monomodular and traditional implants were as likely to develop lordosis (p=0.32), endplate subsidence (p=0.78) or spondylolisthesis (p=0.98). Comparison between endplate subsidence and low bone densitometry were insignificant (p=0.47). Developing lordosis in the monomodular implant was related to low bone density; mean 134vs.184mg/cm. 3. (p=0.018). Three monomodular implants developed a posterior hinge after migrating into lordosis. One traditional implant dislocated, requiring emergency fusion. Radiological outcomes are comparable between traditional and monomodular implants. The larger endplate-footprint of the monomodular implant did reduce subsidence. Monomodular implants pivoting on a posterior hinge may fail early. Bone densitometry may identify patients who will drift into lordosis

Osteoporosis is common and the health and financial cost of fragility fractures is considerable. The burden of cardiovascular disease has been reduced dramatically by identifying and targeting those most at risk. A similar approach is potentially possible in the context of fragility fractures. The World Health Organization created and endorsed the use of FRAX, a fracture risk assessment tool, which uses selected risk factors to calculate a quantitative, patient-specific, ten-year risk of sustaining a fragility fracture. Treatment can thus be based on this as well as on measured bone mineral density. It may also be used to determine at-risk individuals, who should undergo bone densitometry. FRAX has been incorporated into the national osteoporosis guidelines of countries in the Americas, Europe, the Far East and Australasia. The United Kingdom National Institute for Health and Clinical Excellence also advocates its use in their guidance on the assessment of the risk of fragility fracture, and it may become an important tool to combat the health challenges posed by fragility fractures

Periprosthetic fractures around the femur during and after total hip arthroplasty (THA) remain a common mode of failure. It is important therefore to recognise those factors that place patients at increased risk for development of this complication. Prevention of this complication, always trumps treatment. Risk factors can be stratified into: 1. Patient related factors; 2. Host bone and anatomical considerations; 3. Procedural related factors; and 4. Implant related factors. Patient Factors. There are several patient related factors that place patients at risk for development of a periprosthetic fracture during and after total hip arthroplasty. Metabolic bone disease, particularly osteoporosis increases the risk of periprosthetic fracture. In addition, patients that smoke, have long term steroid use or disuse, osteopenia due to inactivity should be identified. A metabolic bone work up and evaluation of bone mineralization with a bone densitometry test can be helpful in identifying and implementing treatment prior to THA. Pre-operative Host Bone and Anatomic Considerations. In addition to metabolic bone disease the “shape of the bone” should be taken into consideration as well. Dorr has described three different types of bone morphology (Dorr A, B, C), each with unique characteristics of size and shape. It is important to recognise that not one single cementless implant may fit all bone types. The importance of templating a THA prior to surgery cannot be overstated. Stem morphology must be appropriately matched to patient anatomy. Today, several types of cementless stem designs exist with differing shape and areas of fixation. It is important to understand via pre-operative templating which stem works best in what situation. Procedural Related Factors. There has been a resurgence in interest in the varying surgical approaches to THA. While the validity and benefits of each surgical approach remains a point of debate, each approach carries with it its own set of risks. Several studies have demonstrated increased risk of periprosthetic fractures during THA with the use of the direct anterior approach. Risk factors for increased risk of periprosthetic fracture may include obesity, bone quality and stem design. Implant Related Factors. As mentioned there are several varying cementless implant shapes and sizes that can be utilised. There is no question that cementless fixation remains the most common mode of fixation in THA. However, one must not forget the role of cemented fixation in THA. Published results on long term fixation with cemented stems are comparable if not exceeding those of press fit fixation. In addition, the literature is clear that cemented fixation in the elderly hip fracture patient population is associated with a lower risk of periprosthetic fracture and lower risk of revision. The indication and principles of cemented stem fixation in THA should not be forgotten

Self-locking button-like fixation devices for ACL reconstruction are attracting knee surgeons' attention due to promising technical advantages: complete filling of the tunnel with graft, anatomic reconstruction (AM portal), fixation achievement even when a short tunnel is reamed, opportunity of graft re-tensioning after tibial fixation and/or cyclic load. We compared two similar devices (TightRope vs ToggleLocZL). 20 fresh-frozen porcine femurs (mean age 2.1 years) were assigned to the two groups by randomization. Hamstrings with 9 mm of diameter were obtained using bovine tendons that show the same biomechanic behaviour of human hamstrings. Femoral tunnel was created by AM portal technique (anatomic position). Zwick-Roell z010 tension/compression device with bone and tendon clamps, was used for the study:. Cyclic test (1000 cycles, 0.5 Hz, 50–250 N/cycle, 50 cycles of preload at 10–80 N/cycle). Final pull-out test (1 mm/s). Failure analysis. CT scan and densitometry. Any implant didn't fail during cyclic test. The elongation average was 2.85±1.63 for ToggleLoc and 2.71±.85 for TightRope (P>0.05). Pull-out test showed different values in terms of Ultimate Strength Failure (USF), Stiffness at USF, and Stiffness:. The failure mode was:. The mean method of failure was the fracture of the cortical bone of the femoral condyle, for both groups. But if we extrapolate the USF the difference was favourable(P<0.05) for TightRope (707.83 N) than ToggleLoc (580.16). The mean bone density of porcine femora was comparable to young human femora (1.12±0.31 BMD). The reproducibility of surgical technique, the mechanical strength and endurance of the systems suggest two valid options for ACL reconstruction with hamstring. ToggleLoc showed worse results due to the sharp squared edges of the button

Transverse pin femoral fixation of bone-patella tendon-bone (BPTB) in ACL reconstruction has been widely applied during the last decades. Aim of our study is to confront two different system of transverse femoral fixation for BPTB graft: Transfix BTB (Arthrex) and BioTransfix T3 (Arthrex). The main differences between these two system are the diameter (3.0 mm Transfix BTB and 3.5 mm BioTransfix T3), and section (Transfix BTB is cannulated). Surgical technique adopts the same transverse vectorial guide but different guide sleeves. 30 fresh-frozen porcine knees (mean age 2.2 years) were assigned to the two groups randomisedly. the patellar bone block and tendon were harvested using the same size in all specimens (10mm × 25 mm, 10 mm). Zwick-Roell z010 tension/compression device with bone clamps, was used for the study:. Cyclic test (1000 cycles, 0.5 Hz, 50–250 N/cycle, 100 cycles of preload). Final pull-out test (1 mm/s). Failure analysis. CT scan and densitometry. Any implant didn't fail during cyclic test. The elongation average was 1.85±0.63 for Transfix BTB and 1.69±0.87 for BioTransfix T3. Pull-out test showed very similar values in terms of Ultimate Strength Failure (USF), Stiffness at USF, and Stiffness:. The failure mode was bone plug fracture (12 for Transfix BTB and 13 for BioTransfix T3) and tendon failure (3 for Transfix BTB and 2 for BioTransfix T3). The post-test CT scan showed any failure of the fixation devices and the correct position inside the femoral half-tunnel. The mean bone density of porcine femora was comparable to young human femora (1.12±0.31 BMD). Both systems showed a similar behaviour in terms of USF, Stiffness, Cyclic load, method of failure and other biomechanical parameters. The reproducibility of surgical technique, the mechanical strength and endurance of the systems suggest two valid options for ACL reconstruction with BPTB even if in-vivo studies are necessary to confirm the animal ex-vivo biomechanical data

Introduction. The following study start from an idea of the evaluation of the osteointegration in the bone cage of the Equinoxe Reverse shoulder prosthesis. The aim of the study is to assess the values of Bone Mineral Density (BMD) in periprosthetic areas, in patients undergoing shoulder arthroplasty with implants of the Equinoxe system by Excatech, Inc. To better understand the steps of osteointegration time of the bone cage with the glenoid. The objectives of the work are not only expanded to the value of osteointegration, but could also be useful for the evaluation of both mechanical and septic loosening of the stem of the glenoid. Materials and Methods. In the period from November 2011 to May 2012, 15 patients were evaluated. All patients were subjected to bone densitometry type of DXA within the first 15 days after surgery and at 3 months after surgery. The patients are all part of a homogeneous group for anatomical glenoid. Were excluded from the study all patients who were no significant alterations of the head and the glenoid. The acquisitions were performed with the patient in an oblique position, with limb in a neutral position, in order to obtain images in the coronal plane “true” of the joint. Were subsequently calculated values of BMD is around the stem with the 7 areas used by Gruen for the hip prosthesis and peripherally to the central peg using 3 areas, superiorly, medially and inferiorly to the same. Results. The values obtained showed a significant increase in the time of bone density peripherally to the central peg demonstrating a significant osteointegration. Being a prospective study these values will be integrated with new acquisition DXA to 6, 9, 12 months, 2, 3 and 5 years. Conclusions. Although preliminary, through our study it was possible to obtain the standard values of BMD in patients with prosthetic replacement has been successful. These BMD values represent a standard of reference for the physiological osseointegration; in the future must be evaluated for their variation in patients with prosthetic loosening and / or with infectious processes, in order to allow an early diagnosis of these diseases by studying DXA. Also in future studies BMD values obtained by us of the Equinoxe prosthesis can be compared with those obtained in other models of the shoulder prosthesis to detect any advantages or disadvantages in terms of osteointegration

Introduction. The purpose of this study was to establish whether men and women with a fragility hip fracture were equally investigated and treated for osteoporosis. Methods. A retrospective review was carried out including 91 patients (48 females, 43 males) who were admitted with a fragility hip fracture between March 2003 and April 2004. Data about age, sex, investigations and medication were collected from the case notes, GP surgeries and the bone densitometry database. Investigations and treatment were compared with current guideline recommendations (SIGN 2003, NICE 2005). Data were analysed using SPSS Version 13.0. Results. According to the guidelines patients < 75 years of age should be investigated and patients > 75 years should be treated for osteoporosis. In our review 33% of women and only 8% of men < 75 years were investigated with a DEXA scan following their hip fracture (Fishers Exact Test, p = 0.32). In patients > 75 years 25% of women and only 6% of men were treated with bisphosphonates (Chi-square = 4.18, p < 0.05). There was also a statistically significant difference in overall treatment including bisphosphonates and calcium/vitamin D between the sexes (Chi-square = 6.81, p < 0.05). Conclusion. This study shows that there is clearly a need for improvement in secondary prevention of fragility fractures in both sexes, but men are significantly less likely to be investigated and treated than women. It is important to include recommendations for men in future guidelines and increase the awareness of male osteoporosis. This is of particular importance as men have a higher morbidity and mortality following hip fractures than women. Orthopaedic surgeons should therefore take on responsibility for these fracture patients and ensure that the process of secondary prevention is initiated

INTRODUCTION:. Clinical densitometry studies indicate that following TKR implantation there is loss of bone mineral density in regions around the implant. Bone density below the tibial tray has been reported to decrease 36% at eight years after TKR. This bone loss (∼5%/year) is substantially greater than osteoporosis patients in the same age group (∼1–2%/year) and could contribute the loss of mechanical support provided by the peri-implant leading to loosening of components in the long term. High patient mass and body mass index have also been implicated in increased loosening rates, and was thought to be due to high stress or strain on the tibial constructs. These findings suggest that peri-implant bone strain may be affected by time in service and patient factors such as body mass. The goal of this project was to assess the proximal tibial bone strain with biomechanical loading using en bloc retrieved TKR tibial components. Note that the implants were not obtained from revision surgery for a loose implant, but rather after death; thus the implants can be considered to be successful for the lifetime of the patient. We asked two research questions, guided by the clinical and laboratory observations: (1) are the peri-implant bone strain magnitudes for cemented tibial components greater for implants with more time in service and from older donors?, (2) is tibial bone strain greater for constructs from donors with high body weight and lower peri-implant BMD?. METHODS:. Twenty-one human knees with cemented total knee replacements were obtained from the SUNY Upstate Medical University Anatomical Gift Program. Clinical bone density scans were obtained of the proximal tibia in the anterior-posterior direction. Axial loads (1 body weight, 60/40% medial to lateral) were applied to the tibia through the contact patches identified on the polyethylene inserts. Strain measures were made using a non-contacting 3-D digital image correlation (DIC) system. Strain was measured over six regions of the bone surface (anterior (A), posterior (P), medial (M), lateral (L), postero-medial (PM), postero-lateral (PL)) (Figure 1). RESULTS:. For a donor population of 54 to 90 years (78 ave) with 0 to 22 years in service (ave 9 years), the peri-implant bone strains ranged from 119 to 791 ue. Maximum strains exceeded 3000 ue. Peri-implant bone strains were greater for implants with more time in service (p = 0.044), but not age of the donor (p = 0.333) (Figure 2). Peri-implant bone strains were greater for donors with greater mass (p = 0.028) and lower bone density (p = 0.0039) (Figure 3). DISCUSSION:. To the authors knowledge, these results show for the first time (using cemented tibial components) that bone remodeling after in-vivo service does not result in constant bone strain as would be expected for ‘homeostatic’ strain conditions. Even though loading was applied based on body weight, heavier donors had higher bone strains. Donors with more time in service also had higher bone strains. Combined, these results suggest that the supporting bone stock could diminish in some patients to the point at which bone failure occurs resulting in component migration