Osteoporotic Bone Conditions Research Articles

'Low-Plane' Fractures of the Distal Humerus in Elderly Patients with Osteoporosis Show High Postoperative Complication Rates.

Background: This study aimed to investigate the fracture patterns and complexity of distal humerus fractures with high-resolution computed tomography (CT) as a function of Dual-Energy X-ray absorptiometry (DXA)-derived bone marrow density (BMD) measurements in an elderly patient cohort. Methods: A retrospective chart review was conducted on patient data collected at a Level I trauma center between January 2007 and January 2022. Inclusion criteria comprised patients aged ≥40 years with a confirmed distal humerus fracture as demonstrated by CT. Additionally, patients were included if they underwent DXA. Patient demographics and detailed information regarding the surgical treatment and trauma mechanism were retrieved from the institutional databank. Fractures were classified as either 'low-plane' distal humeral fractures or 'non-low-plane' distal humerus fractures. Furthermore, the fracture patterns were classified according to established classification systems. Intra- and postoperative complication and revision rates were analyzed. Results: A total of 41 patients (30 women; mean age 74 ± 13 years) were enrolled. Low-energy trauma was sustained by 68% of the patients. The remaining 32% of the fractures involved medium-energy trauma. A total of 62% of the patients underwent primary osteosynthesis, while 30% of patients were initially treated with an external fixator. ORIF was performed in 89% of cases and, in the majority, double-plate osteosynthesis was used (76%). An olecranon osteotomy was performed in 30% of cases. A total of 5% of cases received total elbow arthroplasty, and 10% of cases were treated conservatively. A total of 61% of patients had osteoporosis, 24% of patients had osteopenia, and 15% of patients had a normal BMD with an overall mean T-score of -2.4. Most of the fractures were complex (including 61% Type C fractures). A total of 66% of cases were considered as 'low-plane' fractures. Postoperative complications occurred in 11% of patients (64% of cases among 'low-plane' fractures). Revision surgery was required in 20% of cases. Conclusions: The consecutive series of patients showed a high incidence of 'low-plane' fractures. However, no statistical significance was found between the BMD and fracture complexity. The very distal 'low-plane' fractures showed a high complication rate, which was aggravated by osteoporotic bone conditions. These findings highlight the need for future research with larger patient samples to better understand the relationship between the BMD, fracture complexity, and outcomes in patients with 'low-plane' fractures in order to reduce complications and improve clinical outcomes.

A novel model of locking plate and locking spongious screw: a biomechanical in vitro comparison study with classical locking plate

BackgroundLocking plates are commonly used for the fixation of comminuted, periprosthetic and osteoporotic bone fractures. These plates are secured to the bone with screws, creating a stable connection with fixed angle between the plate and the screws. In this biomechanical in vitro study, our aim is to evaluate and compare the novel locking plate-locking spongious screw model with FDA approved classical locking plate.MethodsSawbone PCF-15 osteoporotic bone model was utilized to simulate osteoporotic bone conditions. Two screws were used to attach both the classical locking plate and the novel locking plate-locking spongious screw model to these bone models. The attachment strength of the screws to the bone blocks was measured by pull-out tests.ResultsNovel locking plate-locking spongious screw model exhibited an 84.38% stronger attachment to the osteoporotic bone model compared to the current locking plate model.ConclusionsIn conclusion, one of the important problems in the locking plates which is the high Pull-out risk of the locking spongious screws can been resolved with our proposed new model and has a chance of having a better purchase especially in osteoporotic bones.

Mechanical property of Ti6Al4V cylindrical porous structure for dental implants fabricated by selective laser melting

The commonly used titanium alloy dental implants currently apply solid structures. However, issues such as stress shielding and stress concentration may arise due to the significant difference in elastic modulus between the implant and host. In order to address these problems, this paper proposes five porous structures based on the Gibson-Ashby theoretical model. We utilized selective laser melting technology to shape a porous structure using Ti-6Al-4V material precisely. The mechanical properties of the porous structure were verified through simulation and compression experiments. The optimal porous structure, which best matched the human bone, was a circular ring structure with a pillar diameter of 0.6 mm and a layer height of 2 mm. The stress and strain of the porous implant on the surrounding cortical and cancellous bone under different biting conditions were studied to verify the effectiveness of the optimal circular ring porous structure in alleviating stress shielding in both standard and osteoporotic bone conditions. The results confirm that the circular ring porous structure meets implant requirements and provides a theoretical basis for clinical dental implantation.

Comparison between primary total elbow arthroplasty versus open reduction and internal fixation in elderly patients with distal humerus fractures: a prospective study

Objective: It aims to assess the efficacy of these treatments, specifically in the presence of osteoporotic bone conditions. The findings of this study offer insights into the suitability of TEA as an alternative treatment option in such cases. Methods: In this study, sixty patients with distal humerus fractures were divided into two groups. The first group received ORIF for fracture fixation, while the second group underwent primary TEA treatment. The study evaluated various outcomes, including elbow range of movement, elbow stability, and comparison of Mayo Elbow Performance Scores (MEPS) between the two groups at three- and twelve-month follow-up periods. Results: In the three- and twelve-month follow-up periods, noticeable differences in elbow motion range were observed between the ORIF and TEA groups. The ORIF group experienced more significant restrictions in daily activities due to stiffness and pain, unlike the TEA group. However, both groups showed improvements in elbow function after one year. Furthermore, there were significant differences in the mean MEPS between the two groups at the three- and twelve-month follow-up period. However, no considerable differences were found between these periods within either group. Conclusion: TEA is emerging as a promising option for elderly patients with comminuted distal humerus fractures, considering the osteoporotic bone condition. The results of this study hold substantial implications for the decision-making process in treatment selection.

Influence of bisphosphonate treatment on bone substitute performance in osteoporotic conditions.

Considering the elevated number of osteoporotic patients in need of bone graft procedures, we here evaluated the effect of alendronate (ALN) treatment on the regeneration of bone defects in osteoporotic rats. Bone formation was histologically and histomorphometrically assessed in rat femoral condyle bone defects filled with bone graft (Bio-Oss®) or left empty. Male Wistar rats were induced osteoporotic through orchidectomy (ORX) and SHAM-operated. The animals were divided into three groups: osteoporotic (ORX), osteoporotic treated with ALN (ORX + ALN) and healthy (SHAM). Six weeks after ORX or SHAM surgeries, bone defects were created bilaterally in femoral condyles; one defect was filled with Bio-Oss® and the other one left empty. Bone regeneration within the defects was analyzed by histology and histomorphometry after 4 and 12 weeks. Histological samples showed new bone surrounding Bio-Oss® particles from week 4 onward in all three groups. At week 12, the data further showed that ALN treatment of osteoporotic animals enhanced bone formation to a 10-fold increase compared to non-treated osteoporotic control. Bio-Oss® filling of the defects promoted bone formation at both implantation periods compared to empty controls. Our histological and histomorphometric results demonstrate that the enteral administration of alendronate under osteoporotic bone conditions leverages bone defect regeneration to a level comparable to that in healthy bone. Additionally, Bio-Oss® is an effective bone substitute, increasing bone formation, and acting as an osteoconductive scaffold guiding bone growth in both healthy and osteoporotic bone conditions. Based on the results of this study, enteral use of ALN mitigates adverse effects of an osteoporotic condition on bone defect regeneration.

Regenerating Critical Size Rat Segmental Bone Defects with a Self-Healing Hybrid Nanocomposite Hydrogel: Effect of Bone Condition and BMP-2 Incorporation.

The aim of the current study is to assess the biological performance of self-healing hydrogels based on calcium phosphate (CaP) nanoparticles and bisphosphonate (BP) conjugated hyaluronan (HA) in a critical size segmental femoral bone defect model in rats. Additionally, these hydrogels are loaded with bone morphogenetic protein 2 (BMP-2) and their performance is compared in healthy and osteoporotic bone conditions. Treatment groups comprise internal plate fixation and placement of a PTFE tube containing hydrogel (HABP -CaP) or hydrogel loaded with BMP-2 in two dosages (HABP -CaP-lowBMP2 or HABP -CaP-highBMP2). Twelve weeks after bone defect surgery, bone formation is analyzed by X-ray examination, micro-CT analysis, and histomorphometry. The data show that critical size, segmental femoral bone defects cannot be healed with HABP -CaP gel alone. Loading of the HABP -CaP gel with low dose BMP-2 significantly improve bone formation and resulted in defect bridging in 100% of the defects. Alternatively, high dose BMP-2 loading of the HABP -CaP gel does not improve bone formation within the defect area, but leads to excessive bone formation outside the defect area. Bone defect healing is not affected by osteoporotic bone conditions.

Effect of Systemic Zoledronic Acid Dosing Regimens on Bone Regeneration in Osteoporotic Rats

The aim of this study was to evaluate the regeneration of bone defects created in the femoral condyle of osteoporotic rats, following intravenous (IV) zoledronate (ZA) treatment in three settings: pre-bone grafting (ZA-Pre), post-bone grafting (ZA-Post), and pre- plus post-bone grafting (ZA-Pre+Post). Twenty-four female Wistar rats were ovariectomized (OVX). After 12 weeks, bone defects were created in the left femoral condyle. All defects were grafted with a particulate inorganic cancellous bovine bone substitute. ZA (0.04 mg/kg, weekly) was administered to six rats 4 weeks pre-bone graft placement. To another six rats, ZA was given post-bone graft placement creation and continued for 6 weeks. Additional six rats received ZA treatment pre- and post-bone graft placement. Control animals received weekly saline intravenous injections. At 6 weeks post-bone graft placement, samples were retrieved for histological evaluation of the bone area percentage (BA%) and remaining bone graft percentage (RBG%). BA% for ZA-Pre (50.1 ± 3.5%) and ZA-Post (49.2 ± 8.2%) rats was significantly increased compared to that of the controls (35.4 ± 5.4%, p-value 0.031 and 0.043, respectively). In contrast, ZA-Pre+Post rats (40.7 ± 16.0%) showed similar BA% compared to saline controls (p = 0.663). For RBG%, all experimental groups showed similar results ranging from 36.3 to 47.1%. Our data indicate that pre- or post-surgical systemic IV administration of ZA improves the regeneration of bone defects grafted with inorganic cancellous bovine-bone particles in osteoporotic bone conditions. However, no favorable effect on bone repair was seen for continued pre- plus post-surgical ZA treatment.

Effect of thread profile on bending strength of pedicle screw

Current pedicle screw designs have not achieved strong bending strength due to varying bone density among patients. Osteoporosis further presents complications in screw fixation and instrumentation failure due patients having less dense bones. We conducted this study to investigate the effect of thread profile on the bending strength of pedicle screw. The study also focus on the bending performance comparison between single threaded and dual threaded pedicle screw via finite element method. The finite element analysis (FEA) was apply to investigate the effect of thread design on the bending strength of pedicle screw (dual threaded, double dual threaded and the dual lead dual threaded screw designs) under normal and osteoporotic bone conditions. The FEA results obtained show that the thread profile does influence the bending strength of a pedicle screw in normal and osteoporotic bones. The dual lead dual threaded pedicle screw showed an improvement of 1.88% in its deflection due to bending. While for the osteoporotic condition, the dual lead dual threaded pedicle screw showed an improvement of 32.3% in term of deflection. Thus, this finding have potential in assisting the optimum pedicle screw design in future although further investigation needed to support this finding.

Biological Effect of Single or Combined Pharmacological Therapy Using Alendronate and Simvastatin on Implant Osseointegration: An In Vivo Study in Healthy and Osteoporotic Rat Models

To evaluate peri-implant bone formation following single or combined systemic administration of alendronate and simvastatin in healthy and osteoporotic rats, eighty female Wistar rats were ovariectomized (n = 40) or sham-operated (n = 40). At six weeks, implants were placed in femoral condyles. Then, ovariectomized (OVX) and sham-operated (SHAM) animals received daily subcutaneous alendronate (50 µg/kg), simvastatin (5 mg/kg), or both, for three weeks. Control animals received subcutaneous saline. Thereafter, specimens were retrieved for biomechanical testing, histological evaluation, and bone area (BA%) and bone-to-implant contact (BIC%). In healthy and osteoporotic rats, similar (p > 0.05) push-out values were observed for all groups. For BA% analysis, control rats showed similar results for OVX (9.2% ± 2.4%) and SHAM (11.1% ± 3.5%) animals. In contrast, single or combined drug therapy significantly increased BA% compared to controls in both healthy and osteoporotic conditions (p < 0.05). In osteoporotic conditions, alendronate alone showed a superior effect on BA% compared to simvastatin alone, or their combination. Systemic alendronate, simvastatin, or both showed a similar BIC% compared to controls (p > 0.05). The present study demonstrates that single or combined systemic alendronate and simvastatin increases bone formation around implants (i.e., distance osteogenesis) in healthy and osteoporotic bone conditions. However, these drugs showed no beneficial effect on direct bone-to-implant contact or implant fixation.

Concept of a Radiofrequency Device for Osteopenia/Osteoporosis Screening

Osteoporosis represents a major health problem, resulting in substantial increases in health care costs. There is an unmet need for a cost-effective technique that can measure bone properties without the use of ionizing radiation. The present study reports design, construction, and testing of a safe, and easy to use radiofrequency device to detect osteoporotic bone conditions. The device uses novel on-body antennas contacting the human wrist under an applied, operator-controlled pressure. For the dichotomous diagnostic test, we selected 60 study participants (23–94 years old, 48 female, 12 male) who could be positively differentiated between healthy and osteopenic/osteoporotic states. The band-limited integral of the transmission coefficient averaged for both wrists, multiplied by age, and divided by BMI has been used as an index. For a 100 MHz frequency band centered about 890–920 MHz, the maximum Youden’s J index is 81.5%. Both the sensitivity and specificity simultaneously reach 87% given the calibration device threshold tolerance of ±3%. Our approach correlates well with the available DXA measurements and has the potential for screening patients at risk for fragility fractures, given the ease of implementation and low costs associated with both the technique and the equipment. The inclusion of radiofrequency transmission data does add supplementary useful information to the available clinical risk factors.

Wicking Property of Graft Material Enhanced Bone Regeneration in the Ovariectomized Rat Model.

Recruitment and homing cells into graft materials from host tissue is crucial for bone regeneration. Highly porous, multi-level structural, hydroxyapatite bone void filler (HA-BVF) have been investigated to restore critical size bone defects. The aim was to investigate a feasibility of bone regeneration of synthetic HA-BVF compared to commercial xenograft (Bio-Oss). HA-BVF of 0.7mm in average diameter was prepared via template coating method. Groups of animals (n = 6) were divided into two with normal (Sham) or induced osteoporotic conditions (Ovx). Subsequently, subdivided into three treated with HA-BVF as an experiment or Bio-Oss as a positive control or no treatment as a negative control (defect). The new bone formation was analyzed by micro-CT and histology. At 4weeks post-surgery, new bone formation was initiated from all groups. At 8weeks post-surgery, new bone formation in the HA-BVF groups was greater than Bio-Oss groups. Extraordinarily greater bone regeneration within the Ovx-HA group than Sham-Bio-Oss or Ovx-Bio-Oss group (p < 0.05). This study suggests that the immediate wicking property of HA-BVF from host tissue activates a natural healing cascade without the addition of exogeneous factors or progenitor cells. HA-BVF may be an effective alternative for repairing bone defects under both normal and osteoporotic bone conditions.

Cement augmentation of the Proximal Femoral Nail Antirotation (PFNA) – A multicentre randomized controlled trial

IntroductionNew implant designs like the Proximal Femoral Nail Antirotation (PFNA) were developed to reduce failure rates in unstable pertrochanteric fractures in the elderly. Standardized implant augmentation with up to 6 mL of polymethylmethacrylate (PMMA) cement has been introduced to enhance implant anchorage by increasing the implant-bone interface in osteoporotic bone conditions. Biomechanically, loads to failure were significantly higher with augmentation. The primary objective of this study was to compare the mobility of patients with closed unstable trochanteric fractures treated by PFNA either with or without cement augmentation. Patients and methodsA prospective multicentre, randomized, patient-blinded trial was conducted with ambulatory patients aged 75 or older who sustained a closed, unstable trochanteric fracture. Surgical fixation had to be performed within 72 h after admission. Outcomes were evaluated at baseline, during surgery, 3 to 14 days after surgery, 3 months, 6 months, and 12 months after surgery. To evaluate the primary objective, patients’ walking speed was assessed by the Timed Up and Go (TUG) test. Secondary objectives included the analysis of implant migration assessed on radiographs, quality of life measured by the Barthel Index, mobility measured by the Parker Mobility Score, and complications. ResultsOf 253 randomized patients, 223 patients were eligible: 105 patients were allocated to the PFNA Augmentation group and 118 to PFNA group. At 3 to 14 days after surgery, there was no statistical significant difference in mean walking speed between the treatment groups. For the secondary objectives, also no statistical significant differences were found. However, no patient in the PFNA Augmentation group had a reoperation due to mechanical failure or symptomatic implant migration compared to 6 patients in the PFNA group. ConclusionsAugmentation of the PFNA blade did not improve patients’ walking ability compared to the use of a non-augmented PFNA but might have the potential to prevent reoperations by strengthening the osteosynthesis construct.

Biomechanical evaluation of a novel dualplate fixation method for proximal humeral fractures without medial support

BackgroundComminuted fractures of the proximal humerus are generally treated with the locking plate system, and clinical results are satisfactory. However, unstable support of the medial column results in varus malunion and screw perforation. We designed a novel medial anatomical locking plate (MLP) to directly support the medial column. Theoretically, the combined application of locking plate and MLP (LPMP) would directly provide strong dual-column stability. We hypothesized that the LPMP could provide greater construct stability than the locking plate alone (LP), locking plate combined with a fibular graft (LPSG), and locking plate combined with a distal radius plate (LPDP).MethodsLP, LPMP, LPSG, and LPDP implants were instrumented into the finite element model of a proximal humeral fracture. Axial, shear, and rotational loads were applied to the models under normal and osteoporotic bone conditions. The whole simulation was repeated five times for each fixator. To assess the biomechanical characteristics, the construct stiffness, fracture micromotion, stress distribution, and neck-shaft angle (NSA) were compared.ResultsThe LPMP group showed significantly greater integral and regional construct stiffness, and endured less von Mises stresses, than the other three fixation methods. The stresses on the lateral locking plate were dispersed by the MLP. The LPMP group showed the least change in NSA.ConclusionsFrom the finite element viewpoint, the LPMP method provided both lateral and medial direct support. The LPMP system was effective in treating proximal humeral fracture with an unstable medial column.

Bone regeneration and gene expression in bone defects under healthy and osteoporotic bone conditions using two commercially available bone graft substitutes

Biosilicate® and Bio-Oss® are two commercially available bone substitutes, however, little is known regarding their efficacy in osteoporotic conditions. The purpose of this study was to evaluate the osteogenic properties of both materials, at tissue and molecular level. Thirty-six Wistar rats were submitted to ovariectomy (OVX) for inducing osteoporotic conditions and sham surgery (SHAM) as a control. Bone defects were created in both femurs, which were filled with Biosilicate® or Bio-Oss®, and empty defects were used as control. For the healthy condition both Biosilicate® and Bio-Oss® did not improve bone formation after 4 weeks. Histomorphometric evaluation of osteoporotic bone defects with bone substitutes showed more bone formation, significant for Bio-Oss®. Molecular biological evaluation was performed by gene-expression analysis (Runx-2, ALP, OC, OPG, RANKL). The relative gene expression was increased with Biosilicate® for all genes in OVX rats and for Runx-2, ALP, OC and RANKL in SHAM rats. In contrast, with Bio-Oss®, the relative gene expression of OVX rats was similar for all three groups. For SHAM rats it was increased for Runx-2, ALP, OC and RANKL. Since both materials improved bone regeneration in osteoporotic conditions, our results suggest that bone defects in osteoporotic conditions can be efficiently treated with these two bone substitutes.

High-frequency loading positively impacts titanium implant osseointegration in impaired bone

High-frequency loading via whole body vibration promotes bone formation and increases bone strength. Whether this translates to positive titanium implant osseointegration in osteoporotic bone was explored in this animal study. An anabolic effect of not only bisphosphonate treatment but also high-frequency loading on implant osseointegration in osteoporotic bone was observed. The present study investigated the impact of high-frequency (HF) loading, applied via whole body vibration (WBV), on titanium implant osseointegration in healthy versus ovariectomy-induced compromised versus pharmacologically treated compromised bone. A custom-made Ti implant was inserted into the metaphyseal tibia of 59 rats and left to heal for either 4 or 14 days. Rats were divided into six groups according to their hormonal and mechanical status. WBV, consisting of 10 consecutive frequency steps at an acceleration of 0.3 g, was applied daily for either 4 or 14 days. Tissue samples were processed for quantitative histology at the tibial cortical and medullar level. Data were analyzed by three-way ANOVA and by post hoc pairwise comparisons. The bone healing response at the interface and surrounding titanium implants was negatively influenced by osteoporotic bone conditions, mainly at the trabecular bone level. Furthermore, the administration of bisphosphonates for preventing the ovariectomy-induced impaired peri-implant response was successful. Finally, the effect of HF WBV loading on the peri-implant bone healing was dependent on the bone condition and was anabolic solely in untreated osteoporotic trabecular bone when applied for an extended period of time. The bone healing response to implant installation is compromised in osteoporotic bone conditions, in particular at the trabecular bone compartment. Meanwhile, not only pharmacological treatment but also mechanical loading via HF WBV can exert a positive effect on implant osseointegration in this specific bone micro-environment. The peri-implant cortical bone, however, seems to be less sensitive to HF WBV loading influences.