Low Bone Quality Research Articles

A long-lasting bisphosphonate partially protects periprosthetic bone, but does not enhance initial stability of uncemented femoral stems: A randomized placebo-controlled trial of women undergoing total hip arthroplasty

Low bone quality may compromise the success of cementless total hip arthroplasty in high-risk patients such as elderly women. Zoledronic acid is a long-lasting antiresorptive agent, which is known to reduce short-term periprosthetic bone loss. However, its effect on femoral stem stability is not well known. Forty-nine female patients with a mean age of 68 years (range, 51–85 years) scheduled to undergo cementless total hip arthroplasty due to osteoarthritis were randomized in this double-blind, placebo-controlled trial to receive a single postoperative infusion of zoledronic acid or placebo. Patients were evaluated for up to four years postoperatively for femoral stem migration measured by radiostereometric analysis, bone mineral density (BMD) measured by dual X-ray absorptiometry, functional recovery, and patient-reported outcome scores. Implant survival was determined at nine years postoperatively. Zoledronic acid did not reduce the femoral stem migration that occurred predominantly during the settling period of the first 3–6 months. Subsequently, all femoral stems were radiographically osseointegrated. Zoledronic acid maintained periprosthetic BMD, while the expected loss of periprosthetic bone during the first 12 months was found in controls. Thereafter, periprosthetic BMD of Gruen zone 7 decreased even in the zoledronic acid group but remained 14.6% higher than that in the placebo group at four years postoperatively. Functional recovery was comparable across the groups. At nine years postoperatively, no revision arthroplasty had been performed. In conclusion, in women at high-risk for low BMD, zoledronic acid had a long-lasting, partially protective effect on periprosthetic bone loss, but the treatment did not enhance the initial femoral stem stability.

Modulation of Micro RNA Expression and Osteoblast Differentiation by Nanotopography.

This study evaluated the expression pattern of micro RNAs (miRNAs) on a surface with nanotopography compared with a smooth surface (control). Human mesenchymal stem cells (hMSCs) were plated on different surfaces and compared at 3, 7, and 14 days for alkaline phosphatase (ALP) activity, expression of genes (osterix [OSX], runt-related transcription factor 2 [RUNX2], bone morphogenetic protein 2 [BMP2], and ALP), and expression of miRNAs. Western blot was also used to detect osteogenic proteins (BMP2, OSX, and osteocalcin [OCN]). Scanning electron microscopy of cells plated onto the surfaces was obtained. ALP activity on different surfaces was significantly greater in the nanotopography surface. At day 14, there was a 3.5-fold and a 9-fold increase for the RUNX2 and OSX genes, respectively. BMP2 and ALP also increased by fourfold and sevenfold compared with the control. Protein levels for OSX and BMP2 were also upregulated compared with the control group. Using RNA sequencing technology (RNA-Seq), a total of 117 miRNAs were found to be differentially expressed comparing the control (day 7) with the nanosurface (day 14). Forty-five miRNAs were upregulated, and 72 were downregulated. Several of the miRNAs that were differently expressed regulate osteogenic genes. For example, hsa-miR-135b-5p targets OCN, BSP, RUNX2, COL15A1, and OSX; hsa-miR-122-5p targets OPN; hsa-miR-196a-5p targets BMP4; hsa-miR-26b-5p targets BMP2; and hsa-miR-148b-3p targets OPN. Surfaces with nanotopography have the potential to improve the osseointegration response in order to reduce the osseointegration time and also increase bone formation around the implants, improving areas with low bone quality. Within the limitation of this study, nanotopography surfaces affected MSC differentiation to osteoblasts. Several miRNAs were differentially regulated by surface topography. These miRNAs could be related to the differentiation response to help control the osseointegration process.

No association between low bone quality and back pain in older adults: A cohort study

It is unclear whether bone quality associates with severity and prognosis of back pain. To investigate the association between bone quality and back pain severity at baseline, and whether low bone quality is a prognostic factor for persistent back pain in patients aged over 55 years at 1-year follow-up. In this prospective cohort study persistent back pain was defined as a decrease in the back pain severity score of less than 30% at 1-year follow-up compared with baseline score or as a back pain severity score greater than 1 (0-10: 0 = no pain) Low bone quality was categorized as a T-score, calculated using a stiffness index by quantitative ultrasound of the heel, of 2.5 or below. Data were analyzed in multiple regression analyses. Of all 513 patients, 68 (13%) showed low bone quality at baseline. Back pain severity showed no differences between patients with normal and with low bone quality. At 1-year follow-up, low bone quality was not associated with persistent back pain (defined as < 30%: OR 1.0; 95% CI: 0.40-2.30, p-value = 0.93; and defined as score > 1: OR 0.4; 95% CI: 0.17-1.15), p-value = 0.09), adjusted for all covariates. In older adults with back pain presenting in general practice, low bone quality was not associated with severity of back pain at baseline nor with persistent back pain at 1-year follow-up.

Influence of short implants geometry on primary stability.

BackgroundA correct design is needed in short implants to improve primary stability (PS) in low quality bone. This study aimed to compare PS of double thread and single thread short implants.Material and MethodsThirty implants with single thread design (PHI/SHORT-I) and 30 implants with double thread design (PHIA/SHORT-I) (Radhex®, Inmet-Garnick S.A., Guadalajara, Spain) were placed in 30 randomly selected bovine ribs. PS was assessed in implant stability quotients (ISQ) and periotest values (PV) with Osstell™ and Periotest® devices, respectively. Computed tomographies of the ribs were taken and bone quality was evaluated in Hounsfield Units (HU) using Ez3D Plus software (Vatech Co., Korea). Only implants placed in low quality bone according to Misch and Kircos classification were selected (D3 bone: 350-850 HU; and D4 bone: 150-350 HU). Ten implants were not included in the study for being placed in D1 and D2 bone. Finally, 50 implants were selected: 17 and 9 PHI/SHORT-I in D3 and D4 bone respectively, and 15 and 9 PHIA/SHORT-I in D3 and D4 bone respectively.ResultsThe one-way ANOVA showed statistically significant differences in ISQ (61.35 ± 4.77 in PHI/SHORT-I and 66.43 ± 4.49 in PHIA/SHORT-I, P<0.005) and PV (-2.76 ± 0.8 and -4.11 ± 1.24 respectively, P<0.005) between two implant designs in D3 bone, and statistically significant differences in ISQ (53.44 ± 3.34 in PHI/SHORT-I and 60.56 ± 1.53 in PHIA/SHORT-I, P<0.0001) and PV (1.13 ± 0.95 and -2.5 ± 0.61 respectively, P<0.0001) between two groups in D4 bone.ConclusionDouble thread design short implants resulted to have higher PS in comparison with single thread design short implants in D3 and D4 bone. Key words:ISQ, osstell, periotest, primary stability, resonance frequency analysis, short implants.

Factors related to the clinical application of orthodontic mini-implants

Orthodontic mini-implants use has been increased. The purpose of this review was to analyze the factors related to the clinical application of orthodontic mini-implants. For the present study, the electronic databases PubMed, MEDLINE, Cochrane, and Google Scholar were searched for available data. The literature search was performed on the articles published from 2003 up to 2017. International peer-reviewed journal articles related to factors which are associated with the clinical application of orthodontic mini-implants were searched. Successful application of mini-implants depends on proper selection of insertion site, proper selection of mini-implant (length, diameter, tapering), proper insertion (site, predrilling, angle, primary stability, injury, and absence of adjacent anatomic structures), absence of inflammation, and proper orthodontic loading. Insertion site and mini-implant characteristics are selected based mainly on cortical bone thickness, bone density, available bone, adjacent anatomic structures, and soft-tissue thickness. Sites of high cortical bone thickness, high cancellous bone density, sufficient available bone, and thin attached gingiva are ideal for mini-implant insertion. Extremely thick cortical bone requires attention. In thick cortical bone, shorter mini-implants can be selected. For sites of low cortical bone thickness and low cancellous bone density, longer and wider mini-implants are indicated. Very thin cortical bone and very low cancellous bone density negatively affect the prognosis of mini-implants. Very narrow implants entail fracture risk. Predrilling is preferred at high bone quality sites, whereas it is used with caution or even be avoided at low bone quality sites. Angled placement might be considered to increase bone-to-implant contact and reduce root injury risk. Loading time depends on insertion torque. Successful application of mini-implants is based on proper insertion site and mini-implant characteristics selection, proper insertion, absence of inflammation, and proper orthodontic loading. Careful assessment of all the factors that might compromise mini-implant success is important for their clinical application.

Osteogenic Potential of Tauroursodeoxycholic Acid as an Alternative to rhBMP-2 in a Mouse Spinal Fusion Model.

The non-union rate after lumbar spinal fusion is potentially as high as 48%. To support efficient bone regeneration, recombinant human bone morphogenetic protein-2 (rhBMP-2) is commonly used as it is regarded as the most potent bone-inducing molecule. However, recently, there have been increasing concerns on the use of rhBMP-2 such as serious complications, including seroma and heterotopic ossification, and the low quality of bone at the center of fusion mass. Thus, many studies were conducted to find and to develop a potential alternative to rhBMP-2. In this study, we investigated the osteogenic potential of tauroursodeoxycholic acid (TUDCA) in the mouse fusion model and compared its effects with rhBMP-2. Twenty-four mice underwent bilateral posterolateral lumbar spinal fusion bone formation at L4-L5. Collagen sponge infused with saline, TUDCA, or rhBMP-2 was implanted at the fusion area. Two and 4 weeks postimplantation, bone formation and tissue regeneration were evaluated via micro-computed tomography and histological analysis. Compared with the TUDCA-treated group, the rhBMP-2 treatment produced a higher amount of bone fusion formation after 2 weeks but also showed higher resorption of the centralized bone after 4 weeks. Interestingly, the TUDCA-treated group developed higher trabecular thickness compared with rhBMP-2 after 4 weeks. Moreover, TUDCA treatment showed distinct angiogenic activity in human umbilical vein endothelial cells as confirmed by an in vitro tube formation assay. Our findings suggest that TUDCA is comparable to rhBMP-2 in supporting bone regeneration and spinal bone formation fusion by increasing trabecular thickness and promoting angiogenesis. Finally, our results indicate that TUDCA can be utilized as a potential alternative to rhBMP-2.

Potential risks of using cement-augmented screws for spinal fusion in patients with low bone quality

Background ContextDramatic increases in the average life expectancy have led to increases in the variety of degenerative changes and deformities observed in the aging spine. The elderly population can present challenges for spine surgeons, not only because of increased comorbidities, but also because of the quality of their bones. Pedicle screws are the implants used most commonly in spinal surgery for fixation, but their efficacy depends directly on bone quality. Although polymethyl methacrylate (PMMA)-augmented screws represent an alternative for patients with osteoporotic vertebrae, their use has raised some concerns because of the possible association between cement leakages (CLs) and other morbidities. PurposeTo analyze potential complications related to the use of cement-augmented screws for spinal fusion and to investigate the effectiveness of using these screws in the treatment of patients with low bone quality. Study DesignA retrospective single-center study. Patient SampleThis study included 313 consecutive patients who underwent spinal fusion using a total of 1,780 cement-augmented screws. Methods and Outcome MeasuresWe analyzed potential complications related to the use of cement-augmented screws, including CL, vascular injury, infection, screw extraction problems, revision surgery, and instrument failure. There are no financial conflicts of interest to report. ResultsA total of 1,043 vertebrae were instrumented. Cement leakage was observed in 650 vertebrae (62.3%). There were no major clinical complications related to CL, but two patients (0.6%) had radicular pain related to CL at the S1 foramina. Of the 13 patients (4.1%) who developed deep infections requiring surgical debridement, two with chronic infections had possible spondylitis that required instrument removal. All patients responded well to antibiotic therapy. Revision surgery was performed in 56 patients (17.9%), most of whom had long construction. A total of 180 screws were removed as a result of revision. There were no problems with screw extraction. ConclusionsThese results demonstrate the efficacy and safety of cement-augmented screws for the treatment of patients with low bone mineral density.

Association of Condylar Bone Quality with TMJ Osteoarthritis

The etiology and treatment of temporomandibular joint (TMJ) osteoarthritis (TMJOA) remain complex and unclear. Based on clinical observations, we hypothesized that low condylar bone quality is significantly correlated with TMJOA and explored this association in a cross-sectional study with human patients. A total of 254 postmenopausal female participants were included in this study. Radiographic findings from cone beam computed tomography (CBCT) and clinical symptoms were used to classify each TMJ data sample as healthy control (n = 124) or TMJOA (n = 130). Condylar bone mineral density (BMD) (computed tomography Hounsfield unit [CT HU]) and bone volume fraction (BV/TV) were measured and modeled as predictors of healthy control versus TMJOA status in multilevel logistic regression analyses. Both CT HU (adjusted odds ratio [AOR] = 0.9989, interquartile odds ratio [IOR] = 0.4206) and BV/TV (AOR= 0.8096, IOR = 0.1769) were negatively associated with TMJOA (P = 0.049, 0.011, respectively). To assess the diagnostic performance of CT HU and BV/TV for identification of TMJOA, receiver operating characteristic (ROC) curves were plotted. The estimated areas under the curve (AUC) were 0.6622 for BV/TV alone, 0.6074 for CT HU alone, and 0.7136 for CT HU and BV/TV together. The model incorporating CT HU and BV/TV together had a significantly higher AUC than the models using BV/TV alone (P = 0.038) or HU alone (P = 0.021). In conclusion, we found that low condylar bone quality was significantly correlated with TMJOA development and that condylar CT HU and BV/TV can be used together as a potential diagnostic tool for TMJOA. Careful clinical evaluation of the condyle coupled with appropriate radiographic interpretation would thus be critical for the early detection of TMJOA.

Performance of laser sintered Ti–6Al–4V implants with bone-inspired porosity and micro/nanoscale surface roughness in the rabbit femur

Long term success of bone-interfacing implants remains a challenge in compromised patients and in areas of low bone quality. While surface roughness at the micro/nanoscale can promote osteogenesis, macro-scale porosity is important for promoting mechanical stability of the implant over time. Currently, machining techniques permit pores to be placed throughout the implant, but the pores are generally uniform in dimension. The advent of laser sintering provides a way to design and manufacture implants with specific porosity and variable dimensions at high resolution. This approach enables production of metal implants that mimic complex geometries found in biology. In this study, we used a rabbit femur model to compare osseointegration of laser sintered solid and porous implants. Ti–6Al–4V implants were laser sintered in a clinically relevant size and shape. One set of implants had a novel porosity based on human trabecular bone; both sets had grit-blasted/acid-etched surfaces. After characterization, implants were inserted transaxially into rabbit femora; mechanical testing, micro-computed tomography (microCT) and histomorphometry were conducted 10 weeks post-operatively. There were no differences in pull-out strength or bone-to-implant contact. However, both microCT and histomorphometry showed significantly higher new bone volume for porous compared to solid implants. Bone growth was observed into porous implant pores, especially near apical portions of the implant interfacing with cortical bone. These results show that laser sintered Ti–6Al–4V implants with micro/nanoscale surface roughness and trabecular bone-inspired porosity promote bone growth and may be used as a superior alternative to solid implants for bone-interfacing implants.

A comparison of bone quality and its determinants in young opioid-dependent women with healthy control group

BackgroundLittle is known about bone quality and its determinants in patients with opioid addiction. The goal of this study was to compare bone quality and its determinants in young opioid addicted women with a local group of young healthy women. MethodUsing cross-sectional design, 104 women (mean age 29.9 yrs, range: 20–40 yrs, SD=7.8) with previous opioid addiction and current methadone substitution (3–30mg, daily) for 1–16 weeks were compared to 117 healthy women (mean age 31.0 yrs, range: 20–40 yrs, SD=5.9). Bone quality was examined with quantitative ultrasound. Anthropometric characteristics (body weight, fat free mass (FFM), fat mass) were obtained by bioelectrical impedance analysis. Substance use and other risk factors for low bone quality were assessed by questionnaire-based interviews. ResultsMore than one-quarter (34%) of patients had osteopenia (n=31) or osteoporosis (n=4), compared to 16% of the healthy control group having osteopenia (n=18). Bivariate correlation analysis demonstrated that age, body weight, and FFM correlated with bone quality (p<0.05) in healthy women, which were not found in patients. Multivariate analyses showed that in healthy controls, the determinants of bone quality were age, body height, physical activity, and BMI, but in patients, the determinant of bone quality was duration of drug intake. ConclusionsLong-term opioid dependence in young women may lead to low bone quality. Efforts to increase awareness of low bone quality in young opioid addicted women should be considered so that effective treatment may be employed to lower future fracture risk.

Increased bone quantity around an ailing implant in esthetic zone using progressive bone loading: A case report

Introduction: Progressive loading protocol is a high-demanding procedure suggested to increase the quality of bone when the implant is inserted in D3 or D4-typed bone. The purpose of this study was to present a case report regarding simultaneously progressive and immediately loading implants in the anterior position of the maxilla. Case report: One patient whose implants in the anterior maxilla (in site of teeth #7, #9, #11) had questionable to poor prognosis who was treated immediate and delayed progressive loading protocol and was followed up for 2 years. Discussion: Although the number of studies in this field is limited, it can be concluded that the progressive loading protocol can predictably enhance the treatment success in immediate-loaded implants with poor prognosis and when inserted in low quality bone such as the present case.

Intermittent Parathyroid Hormone Improves Bone Formation Around Titanium Implants in Osteoporotic Rat Maxillae.

Parathyroid hormone (PTH) plays an important role in the treatment of osteoporosis due to its anabolic effect. In this study, PTH was administered intermittently to rats with ovariectomy-induced osteoporosis, titanium implants were placed into the rat maxillae, and the response of surrounding bone was evaluated. A total of 30 female 8-week-old Sprague-Dawley rats were either ovariectomized to induce osteoporosis or sham operated. After 8 weeks, the upper right first molar was extracted and after a 4-week healing period an implant was placed. The animals were then divided into three groups: the PTH group (n = 10), which had been ovariectomized and received postimplant PTH; the OVX group (n = 10), which had been ovariectomized but did not receive postimplant PTH; and the control group (n = 10), which had been sham operated only (n = 10). Following implant placement, the rats in the PTH group received intermittent doses (three times a week) of PTH (30 μg/kg) subcutaneously in the dorsum. All the rats were sacrificed 4 weeks after implantation and specimens of the peri-implant maxillary bone were harvested, including the implant. Samples were evaluated by histomorphometric analysis and three-dimensional microcomputed tomography. Histomorphometric results showed that the mean bone area per tissue area (BA/TA) was 54.16% ± 2.2% in the PTH group and 45.24% ± 6.3% in the OVX group. The percentage of bone-to-implant contact (BIC) was 45.58% ± 9.4% in the PTH group and 32.00% ± 10.9% in the OVX group. Mean BA/TA and mean BIC values in the PTH group were higher than those in the OVX group; however, the differences were not statistically significant (P > .05). Microstructural data also showed differences between the groups. Bone volume was greater and trabecular bone was thicker in the PTH group than in the OVX group and more trabeculae were found in the PTH group. Bone mineral density was also higher in the PTH group. However, statistical analysis failed to show a significant difference between these two groups in any parameters other than trabecular thickness (P = .023). Despite the limitations of this study, intermittent PTH administration in humans may be helpful in accelerating new bone formation around implants. PTH treatment could improve clinical outcomes when dental implants are placed in jaws with low-quality bone.

Multicenter analysis of CIREN occupant lumbar bone mineral density and correlation with age and fracture incidence

ABSTRACTObjective: This study aimed to quantify lumbar volumetric bone mineral density (vBMD) for 873 seriously injured Crash Injury Research and Engineering Network (CIREN) motor vehicle crash occupants (372 male, 501 female) from 8 centers using phantomless computed tomography scans and to associate vBMD with age, fracture incidence, and osteopenia/osteoporosis diagnoses. The novelty of this work is that it associates vBMD with region of injury by applying an established method for vBMD measurement using phantomless computed tomography (CT).Methods: A validated phantomless CT calibration method that uses patient-specific fat and muscle measurements to calibrate vBMD measured from the L1–L5 trabeculae was applied on 873 occupants from various CIREN centers. CT-measured lumbar vBMD < 145 mg/cc is indicative of osteopenia using a published threshold. CIREN occupant lumbar vBMD in milligrams per cubic centimeter was regressed against age, osteopenia/osteoporosis comorbidities, height, weight, body mass index (BMI), and the incidence of fracture in vertebral (cervical, thoracic, lumbar) and rib/sternum regions.Results: Among the 873 occupants analyzed, 11% (92 occupants) were diagnosed as osteopenic in CIREN. Of these 92 occupants, 42% (39 occupants) had normal vBMD measures (≥145 mg/cc), suggesting possible misclassification in CIREN. Of the 134 occupants classified as osteopenic in vBMD analysis, 60% were not classified as osteopenic in CIREN, suggesting undiagnosed osteopenia, and 40% were correctly classified in CIREN. Age was negatively correlated with vBMD (P <.0001) and occupants with <145 mg/cc vBMD sustained a median number of 2 rib/sternum fractures compared to a median value of 0 rib/sternum fractures for the ≥145 mg/cc vBMD group (P <.0001). Vertebral fracture analysis revealed that the thoracolumbar region was the most common region of injury in the spine. Though the incidence of fracture was not significantly different in the thoracic (10% versus 6%, P =.122) and lumbar (16% versus 13%, P =.227) regions between the 2 bone quality groups, the proportion of thoracolumbar fractures was significantly higher in occupants with <145 mg/cc vBMD versus occupants with ≥145 mg/cc vBMD (24% versus 17%, P =.043).Conclusions: Low lumbar vertebral bone quality is associated with an increased number of rib/sternum fractures and a greater incidence of thoracolumbar vertebral body fractures within the CIREN population analyzed.

Peri-prosthetic femoral fractures of hip or knee arthroplasty. Analysis of 34 cases and a review of Spanish series in the last 20 years

PurposeTo evaluate peri-prosthetic femoral fractures by analysing type of patient, treatment and outcomes, and to compare them with Spanish series published in the last 20 years. Material and methodsA retrospective review of the medical records of patients with peri-prosthetic femoral fractures treated in our hospital from 2010 to 2014, and telephone survey on the current status. ResultsA total of 34 peri-prosthetic femoral fractures were analysed, 20 in hip arthroplasty and 14 in knee arthroplasty. The mean age of the patients was 79.9 years, and 91% had previous comorbidity, with up to 36% having at least 3 prior systemic diseases. Mean hospital stay was 8.7 days, and was higher in surgically-treated than in conservative-treated patients. The majority (60.6%) of patients had complications, and mortality was 18%. Functional status was not regained in 61.5% of patients, and pain was higher in hip than in knee arthroplasty. DiscussionPeri-prosthetic femoral fractures are increasing in frequency. This is due to the increasing number of arthroplasties performed and also to the increasing age of these patients. Treatment of these fractures is complex because of the presence of an arthroplasty component, low bone quality, and comorbidity of the patients. ConclusionPeri-prosthetic femoral fractures impair quality of life. They need individualised treatment, and have frequent complications and mortality.

High frequency of vertebral fracture and low bone quality in patients with rheumatoid arthritis—Results from TOMORROW study

Objectives: Osteoporosis is one of the complications in patients with rheumatoid arthritis (RA). In this study, we researched the morbidity of existing vertebral fractures and the risk factors for vertebral fractures in patients with RA.Methods: This study included 413 participants, 208 patients with RA, and 205 age- and sex-matched controls without RA. Clinical data, radiographic assessment of vertebral fracture from T4 to L4 in thoracic and lumber spine, bone mineral density (BMD), and bone metabolic markers (BMM) were analyzed.Results: Vertebral fractures were observed more frequently, severe and multiple in patients with RA. In the logistic regression analysis, age (adjusted odds ratios (OR): 1.07, 95% confidence interval (CI): 1.04–1.09) and RA (adjusted OR: 1.72, 95% CI: 1.04–2.83) were risk factors for existing vertebral fracture. Moreover, two bone matrix-related markers, undercarboxylated osteocalcin (ucOC) (adjusted OR: 1.68, 95% CI: 1.02–2.78), and urinary pentocidine (adjusted OR: 2.51, 95% CI: 1.48–4.24) were associated with existing vertebral fracture.Conclusions: High frequent, multiple, and severe vertebral fractures were found in patients with RA compared to the controls. Low bone quality might be the cause of the frequent prevalence of vertebral fracture in patients with RA.

Biomechanical Effect of Prosthetic Connection and Implant Body Shape in Low-Quality Bone of Maxillary Posterior Single Implant-Supported Restorations.

Dental implant macrogeometry parameters, such as the prosthetic connection and implant body shape, can influence the biomechanical behavior of the restoration. Using tridimensional finite element analysis (3D-FEA), this study evaluated the biomechanical behavior of two implant macrodesign parameters (prosthetic connection and implant body shape) in low-quality bone. Four groups were obtained by the combination of external hexagon and Morse taper connections, and cylindrical and conical body shapes. Implants (4ø × 10-mm) with a microthread collar and triangular thread shape received a single abutment and monolithic zirconia crown on the maxillary first molar. Bone was constructed on the basis of cross-sectional images of the posterior human maxilla obtained by cone beam computed tomography. A 200-N axial loading was distributed on five points of the occlusal surface. Data were acquired as shear stress (τmax, in megapascals) and strain (εmax, in micrometers) in the cortical and trabecular bone. The external hexagon groups generated higher shear stress/strain values compared with Morse taper groups in the cortical bone, regardless of implant body shape. In the trabecular bone, the highest τmax and εmax values were observed in the Morse taper conical implant group (6.94 MPa and 21.926 × 10⁻⁴ μm, respectively), and the lowest values were observed in the external hexagon cylindrical implant group (4.47 MPa and 9.3155 × 10⁻⁴ μm, respectively). The magnitudes of shear stress and strain in the peri-implant region of low-quality bone was lower with the use of Morse taper connection and cylindrical implants compared with external hexagon connection and conical implants.

Fracturas periprotésicas de fémur sobre prótesis de cadera y rodilla. Análisis de una serie de 34 casos y revisión de las series españolas en los últimos 20 años

PurposeTo evaluate peri-prosthetic femoral fractures by analysing type of patient, treatment and outcomes, and to compare them with Spanish series published in the last 20 years. Material and methodsA retrospective review of the medical records of patients with peri-prosthetic femoral fractures treated in our hospital from 2010 to 2014, and telephone survey on the current status. ResultsA total of 34 peri-prosthetic femoral fractures were analysed, 20 in hip arthroplasty and 14 in knee arthroplasty. The mean age of the patients was 79.9 years, and 91% had previous comorbidity, with up to 36% having at least 3 prior systemic diseases. Mean hospital stay was 8.7 days, and was higher in surgically-treated than in conservative-treated patients. The majority (60.6%) of patients had complications, and mortality was 18%. Functional status was not regained in 61.5% of patients, and pain was higher in hip than in knee arthroplasty. DiscussionPeri-prosthetic femoral fractures are increasing in frequency. This is due to the increasing number of arthroplasties performed and also to the increasing age of these patients. Treatment of these fractures is complex because of the presence of an arthroplasty component, low bone quality, and comorbidity of the patients. ConclusionPeri-prosthetic femoral fractures impair quality of life. They need individualised treatment, and have frequent complications and mortality.

Pull-out stability of anchors for rotator cuff repair is also increased by bio-absorbable augmentation: a cadaver study.

Osteoporosis is a highly focused issue in current scientific research and clinical treatment. Especially in rotator cuff repair, the low bone quality of patients suffering from osteoporosis is an important issue. In this context, non-biological solutions using PMMA for anchor augmentation have been developed in the recent past. The aim of this study was to evaluate whether augmentation of suture anchors using bio-absorbable osteoconductive fiber-reinforced calcium phosphate results in improved failure load of suture anchors as well. Altogether 24 suture anchors (Corkscrew FT 1 Suture Anchors, Arthrex, Naples, FL, USA) were evaluated by applying traction until pullout in 12 paired fresh frozen human cadaver humeri using a servo-hydraulic testing machine. Inclusion criteria were an age of more than 64years, a macroscopically intact RC and an intact bone. The anchors were evaluated at the anterolateral and posteromedial aspect of the greater tuberosity. 12 suture anchors were augmented and 12 suture anchors were conventionally inserted. The failure load was significantly enhanced by 66.8% by the augmentation method. The fiber-reinforced calcium phosphate could be easily injected and applied. The bio-absorbable cement in this study could be a promising augmentation material for RC reconstructions, but further research is necessary-the material has to be evaluated in vivo.

Staphylococcal orthopaedic device-related infections in older patients

IntroductionStaphylococci are the most common pathogens causing orthopaedic device-related infections (ODRI). The treatment of these infections often involves multiple surgical procedures combined with systemic antibiotic therapy to treat the infection and restore functionality. Older patients frequently present with a compromised health-status and/or low bone quality, and despite growing importance their outcomes are not well described to date. The primary aim of the current study is to describe outcomes in older patients with ODRIs and to determine if they demonstrate lower cure rates and greater risk for complications in contrast to younger patients. Patients and methodsPatients treated with an ODRI of the lower extremity at our institution were included in this study. Demographic data, comorbidities and infecting organisms were recorded. Older adult patients were defined as those aged 60 and older. At two-year follow-up post-discharge, we recorded the clinical course, the Lower-Extremity-Functional-Score, the patient reported general health status (SF-12-questionnaire) and the status of infection. The antibiotic resistance pattern of the disease causing pathogens was analysed and compared between the two age groups. ResultsIn total, 163 patients (age: 19–94 years) with a staphylococcal ODRI were included. Sixty-four of these infections occurred in older patients, which showed a significantly higher mortality rate (9%). Within follow-up period recurrence of infection occurred significantly more frequently in younger patients (41%) than in older patients (17%). At two-years follow-up cure, which was defined as eradication of infection and terminated therapy, was achieved in 78% of younger and 75% of older patients. However, an ODRI resulted in older patients in a significantly worse functional outcome and impaired physical quality of live, as well as more frequently in an on-going infection, such as a persisting fistula (14% versus 3% in younger patients). Disease causing staphylococci, isolated from older patients showed more frequently a methicillin or multi-drug resistance than those associated with infections in younger patients. ConclusionsODRIs in older patients demonstrated higher morality rates rate, poor functional outcome and higher rates of persistent infections. A compromised health status and a poor bone quality may play a crucial role in this specific patient cohort.

Automated radiogrammetry is a feasible method for measuring bone quality and bone maturation in severely disabled children.

BackgroundChildren with severe neurological impairment and intellectual disability are prone to low bone quality and fractures.ObjectiveWe studied the feasibility of automated radiogrammetry in assessing bone quality in this specific group of children. We measured outcome of bone quality and, because these children tend to have altered skeletal maturation, we also studied bone age.Materials and methodsWe used hand radiographs obtained in 95 children (mean age 11.4 years) presenting at outpatient paediatric clinics. We used BoneXpert software to determine bone quality, expressed as paediatric bone index and bone age.ResultsRegarding feasibility, we successfully obtained a paediatric bone index in 60 children (63.2%). The results on bone quality showed a mean paediatric bone index standard deviation score of −1.85, significantly lower than that of healthy peers (P < 0.0001). Almost 50% of the children had severely diminished bone quality. In 64% of the children bone age diverged more than 1 year from chronological age. This mostly concerned delayed bone maturation.ConclusionAutomated radiogrammetry is feasible for evaluating bone quality in children who have disabilities but not severe contractures. Bone quality in these children is severely diminished. Because bone maturation frequently deviated from chronological age, we recommend comparison to bone-age-related reference values.