Search Results (605)

Background: Long-bone non-unions complicated by osteomyelitis remain a major reconstructive and healthcare challenge, particularly in resource-limited settings with a high prevalence of multidrug-resistant (MDR) pathogens. Conventional staged management is associated with a prolonged treatment burden, repeated procedures, and delayed functional recovery. This study evaluated the clinical, radiological, functional, and short-term safety outcomes of a single-stage approach using custom-threaded antibiotic-coated locking nails (TACLNs) in a high-resistance cohort. Methods: This prospective single-center cohort study enrolled 30 adults with osteomyelitis-associated femoral or tibial nonunion at a tertiary hospital in Peshawar, Pakistan. All patients underwent radical debridement and single-stage stabilization with a chest tube mold TACLN loaded with vancomycin and gentamicin, with culture-directed adjunctive antibiotics for resistant organisms. Outcomes were assessed at baseline, Weeks 3 and 6, and Month 6 using inflammatory markers, RUST score, VAS pain, EQ-5D-5L, ASAMI criteria, and return to work or usual activity. No formal sample size calculation was performed, and this study was exploratory in nature. Results: The cohort (mean age 44.9 ± 9.9 years) had a challenging microbiological profile, with 40.0% MDR and 13.3% extensively drug-resistant (XDR) infections. By Month 6, short-term infection control was achieved in 96.7% of patients, with significant reductions in ESR and CRP (both p < 0.001). Radiographic union was achieved in 90.0% of cases at a mean of 18.6 weeks, and the mean RUST score improved from 4.87 to 10.43 at the final follow-up. The VAS pain decreased from 5.23 at week 3 to 0.73 at month 6, EQ-5D-5L improved from 0.39 to 0.84, and 90.0% returned to work or usual activity by month 6. No cement debonding, implant failure, or nephrotoxicity was noted. Conclusions: In this single-arm exploratory cohort, TACLNs were associated with favorable short-term infection control, radiographic union, and functional recovery in osteomyelitis-associated long-bone nonunion, including in an MDR/XDR setting. The independent contribution of the threaded core design cannot be established. Larger multicenter comparative studies with longer follow-ups are needed to confirm the durability and implementation feasibility. Full article

Treatment for large critical-sized bone defects and impaired fracture healing remain challenging. Clinically used protein-based osteoinductive factors, such as recombinant bone morphogenetic proteins (BMPs), can be effective; however, they are costly and limited by stability, dose-delivery issues, and safety concerns. Preclinical small molecules offer an alternative because they are chemically stable, scalable to manufacture, and readily integrated for systemic administration or localized release from scaffolds, hydrogels, cements, and implant coatings. With an emphasis on delivery formats and mechanistic themes, this review examines small molecules that have been shown to improve bone regeneration in preclinical models, contrasting those of biological origin with synthetic and repurposed compounds. Across studies, these selected compounds promote osteoblast commitment, differentiation, and matrix mineralization via BMP/Smad signaling and Wnt/beta-catenin (β-catenin) activation, often through glycogen synthase kinase-3 beta (GSK-3β) inhibition or relief of pathway antagonism or Hedgehog (Hh) pathway stimulation. Beyond osteoinduction, several candidates address issues that commonly limit repair, including angiogenesis, oxidative stress, inflammatory tone, osteoimmune regulation, and suppression of osteoclast-mediated resorption. Direct head-to-head comparisons are rare across both classes and reporting heterogeneity complicates interpretation. Key translational gaps include limited cytotoxicity and immunologic profiling, dose and release optimization, durability of benefit, and insufficient evaluation of rational combinations. More rigorous in vivo studies, including larger animal models and standardized outcome metrics, are needed to prioritize promising candidates and guide clinical development. Full article

Background: Cemented fixation remains the standard for total knee arthroplasty (TKA), with Palacos^® R considered the gold standard bone cement. However, more cost-efficient alternatives, like Biomet Bone Cement^® (BBC), require evaluation to confirm comparable outcomes. This retrospective 5-year study compares the clinical safety, performance, and radiographic outcomes of BBC versus Palacos-R in primary TKA, highlighting BBC’s potential as a comparable, cost-effective option amid the increasing cost of outpatient surgeries. Methods: This is a single-center, retrospective study of 128 consecutive patients undergoing primary TKA, evaluated over 5 years. The first 64 patients received Palacos-R, and the subsequent 64 patients received BBC. Radiographic outcomes, including cement gaps, radiolucency, periprosthetic osteolysis, and subsidence, were assessed using the Knee Society Radiographic scheme at immediate post-operative, 6-month, 1-year, 3-year, and 5-year intervals. Clinical outcomes were measured using the Knee Society Score (KSS) and the University of California Los Angeles Activity (UCLA) score. Statistical analyses included chi-square, Fisher’s exact tests, and t-tests (p < 0.05). Results: Cement gaps were significantly higher in the Palacos-R cohort at immediate postop (p = 0.0002) and 1-year (p = 0.0003), with no significant difference at 3 and 5 years. Radiolucency was non-progressive (<2 mm) in both cohorts. KSS was significantly higher in the Palacos-R group at 6 months, 1 year, and 3 years (p < 0.001), but equivalent at 5 years (p = 0.42). UCLA scores showed no differences. No revisions were required in either cohort. Conclusions: While BBC demonstrated comparable radiographic stability and clinical outcomes to Palacos at 5 years with no revisions in either cohort, the absence of preoperative KSS and UCLA scores is a major limitation that prevents adjustment for baseline function and limits interpretation of the early postoperative KSS differences. Full article

This study proposes a novel semi-discrete model of non-ordinary state-based peridynamics. It is used to simulate the tensile failure process of dog bone-shaped specimens of 3D-printed fiber-reinforced concrete with 0%, 1% and 2% fiber volume fractions. The results are compared with the literature laboratory results to verify the feasibility and reliability of the approach. In addition, it is utilized for a 3D-printable engineered cement-based composite (ECC) disk splitting simulation. Effects of different fiber lengths, printing interfaces, and fiber orientations on the failure process of disc specimens are investigated. It is found that ductile failure appears in the loading direction, while brittle failure appears in the other direction. Effect of fiber length on the bearing capacity is feeble. In addition, the non-ordinary state-based peridynamics semi-discrete model is used to simulate the crack propagation of three-point bending. The principal stress contours, damage diagrams, and displacement–load curves of the concrete matrix at different time steps during the crack propagation process are obtained. The simulation is in great agreement with the experimental results. Finally, it is demonstrated that the novel non-ordinary state-based peridynamics approach proposed in this paper is accurate and efficient to simulate fracture behavior of 3D-printed ECC beams. Full article

Magnesium potassium phosphate cement (MKPC) is a promising bone repair material but suffers from excessively rapid setting time (typically within minutes) that limits clinical application. This study systematically investigates trimagnesium phosphate (TMP) as a candidate retarding additive for MKPC. TMP was used to partially replace dead-burned magnesium oxide at replacement levels of 0%, 10%, and 15% by mass. The effects of TMP content, water-to-cement ratio (0.17–0.23), and magnesium-to-phosphate molar ratio (4–10) on setting time, fluidity, hydration kinetics, compressive strength, and microstructure were comprehensively evaluated. Results show that TMP effectively extends the setting time from 9–13 min (without TMP) to 10–19 min, providing a working window that may be suitable for biomedical applications requiring extended handling time. Notably, 10% TMP incorporation enhances early compressive strength, with 1-day strength reaching 35.2 MPa compared to 28.5 MPa for control samples. Hydration heat analysis reveals TMP moderates the acid-base reaction kinetics through its slower dissolution rate compared to MgO. Microstructural characterization shows TMP promotes the formation of denser K-struvite crystals with refined microstructure. The optimal TMP dosage of 10% achieves a balanced performance, extending setting time while improving early strength and microstructural densification. These findings establish TMP as an effective retarder for developing MKPC-based materials with potential for biomedical applications, pending further biological validation. Full article

Periprosthetic joint infection (PJI) is a devastating complication after total joint arthroplasty, typically managed through a two-stage revision protocol involving antibiotic-loaded spacers. This study aimed to evaluate the clinical outcomes and safety of a new multiple high-dose antibiotic-loaded cement (MHDALC) spacer against alternative classical antibiotic combinations for Gram-positive PJI. In this retrospective observational study of 102 patients (30 MHDALC vs. 72 control), the MHDALC cohort received spacers prepared with commercial cement (1 g clindamycin and 1 g gentamicin per 40 g) supplemented with manual additions of 4 g vancomycin and 2 g ceftazidime per 40 g of cement, while the control group received the same commercial cement supplemented with 4 g of vancomycin alone. Treatment failure was significantly lower in the MHDALC group (6.6%) compared to the control group (20.8%; p = 0.005). Furthermore, the time to second-stage reimplantation was drastically reduced in the MHDALC cohort (9.1 vs. 17.8 weeks; p = 0.001). Despite the substantially higher antibiotic load, no significant differences were observed regarding mechanical or surgical complications between the two groups (p = 1.00). In conclusion, the use of MHDALC spacers is an effective and safe strategy for treating Gram-positive PJI, significantly improving eradication rates and accelerating the transition to definitive reconstruction without compromising structural integrity. Full article

Birmingham hip resurfacing (BHR) is an alternative to bone-sparing total hip arthroplasty; however, failures may be associated with the cementing technique. This study aimed to evaluate the characteristics of the cement layer and potential failure mechanisms. BHR explants were analyzed using radiographic evaluation, stereomicroscopy, scanning electron microscopy (SEM), and histopathology. The cement layer was nonuniform, with excessive thickness in the dome regions and insufficient lateral coverage. Increased cement penetration values exceeded recommended thresholds. SEM analysis revealed inhomogeneous cement with cracks, air inclusions, and loosening at the cement–prosthesis interface. BHR failure may be associated with a complex interplay between cementation parameters, cement mantle morphology, and the biological response at the bone–cement interface, as well as interactions at the cement–prosthesis interface. Microscopic evaluation may provide valuable insights into the mechanisms potentially contributing to BHR prosthesis failure. Full article

Background and Objectives: Complicated osteoporotic thoracolumbar fractures represent a major surgical challenge because compromised bone quality predisposes to progressive deformity, neurological deterioration, and fixation failure. This study aimed to evaluate the clinical and radiological outcomes of hybrid stabilization in patients with severe osteoporotic fractures classified as AO Spine-DGOU OF4–OF5. Materials and Methods: This single-center retrospective observational cohort study included 87 consecutively treated patients with complicated osteoporotic thoracolumbar fractures who underwent surgical treatment between 2012 and 2022. Clinical outcomes were assessed using the Visual Analog Scale (VAS) and Oswestry Disability Index (ODI). Radiological outcomes included the regional kyphotic angle (RKA) and interbody fusion graded according to the Bridwell classification. Imaging was reviewed preoperatively, immediately postoperatively, and at follow-up, with 12-month outcomes used for the principal analysis. Additionally, a retrospective comparative analysis was undertaken between the two largest fixation subgroups within the cohort to explore outcome differences across the most representative construct patterns. Results: At 12 months, complete interbody fusion (Bridwell grade I) was achieved in 75.9% of patients. Mean RKA improved from 29.4° ± 14.1° preoperatively to 7.9° ± 8.0° immediately after surgery, with only minimal loss of correction during follow-up. Mean VAS improved from 7.0 ± 1.8 to 2.1 ± 1.2, while mean ODI decreased from 61.3% ± 6.8% to 9.8% ± 1.2% (both p < 0.001). Reoperation for implant-related mechanical failure was required in three patients (3.4%). Conclusions: Hybrid stabilization with cement augmentation was associated with marked improvement in pain, functional disability, and sagittal alignment, as well as a high rate of interbody fusion at 12 months, in patients with complicated osteoporotic thoracolumbar fractures. Given the retrospective observational design, these findings should be interpreted as associations within the treated cohort. Prospective comparative studies are warranted to further validate these results. Full article

Low-density cancellous bone results in reduced trabecular support and may increase crestal cortical strain around implants. Osseodensification (OD) compacts trabecular bone and may create a peri-osteotomy densified zone, but its strain-level effects in osteoporotic-like bone are unclear. This study evaluated whether an OD-inspired peri-implant densified trabecular zone reduces crestal cortical strain compared with conventional drilling (CD) in an osteoporotic-like model. A three-dimensional finite element model of a mandibular posterior segment with a 2.0-mm cortical shell and D4 cancellous core was constructed with a 4.3 × 11.4-mm titanium implant and a cemented monolithic zirconia crown. CD used a 4.0-mm osteotomy in D4 bone. The OD model used the same osteotomy plus a concentric peri-implant densified shell with radial density gradation from D1 to D3. The implant–bone interface was defined as bonded. Static 100 N axial and 45° oblique loads were applied. Outcomes were ε_eq, ε_max, and ε_min, summarized as mean top-10 nodal values. OD reduced crestal cortical strains under both loads. Under axial loading, ε_eq, ε_max, and |ε_min| decreased by 17.7%, 19.0%, and 24.1%, respectively. Under oblique loading, the corresponding reductions were 9.8%, 8.0%, and 8.9%. Oblique loading produced higher cortical strains than axial loading in both models. OD-inspired peri-implant densification reduced crestal cortical strain in this osteoporotic-like model, whereas oblique loading remained the main driver of elevated strain. These findings support occlusal/prosthetic strategies that minimize oblique forces and warrant experimental and clinical validation. Full article

Background: Periprosthetic joint infection and native hip infections often require staged surgical intervention due to extensive bone and soft tissue destruction. This study evaluates the clinical feasibility and mechanical reliability of a modified functional articulating hip spacer (FAHS) incorporating a cemented dual-mobility-bearing (DMB) metal liner. Methods: We retrospectively reviewed the cases of 20 patients who underwent a DMB-incorporated FAHS between March 2018 and December 2019. The technique involved cementing a DMB metal liner directly into the prepared acetabulum without a standard outer shell. Successful clinical outcome was defined as either transition to second-stage total hip arthroplasty (THA) or stable spacer retention, the latter including cases with definitive eradication or symptom-controlled chronic suppression therapy. Infection eradication required the clinical absence of infection for at least twelve months following the cessation of antimicrobial therapy. Construct-related mechanical complications and radiographic parameters were also analyzed. Results: The mean follow-up was 23.5 months, ranging from 6.0 to 62.6 months. Successful clinical outcome was achieved in 17 patients (85%), with seven (35%) transitioning to second-stage THA and ten (50%) opting for spacer retention. Within the retention group, seven achieved definitive eradication while three were maintained under chronic suppression therapy. Construct integrity was maintained in 80% of the cohort. Mechanical complications included two dislocations (10%) and two implant failures (10%). Radiographic analysis showed higher inclination and anteversion angles of the metal liner in the dislocation cases. Conclusions: The off-label use of DMB-incorporated FAHS represents a feasible option with acceptable mechanical performance in selected cases of PJI and native hip joint infection. However, as mechanical complications cannot be fully prevented, meticulous surgical techniques and careful patient selection remain essential. Full article

Background: Revision total knee arthroplasty (rTKA) is a technically demanding procedure that, when performed using mechanically aligned strategies, frequently relies on stems, augments, metaphyseal cones and constrained implants to restore knee alignment and stability. In carefully selected cases with preserved metaphyseal bone stock and competent collateral ligaments, robotic assistance allows a bone-preserving strategy in which alignment, joint line height, and soft-tissue balance are restored using conventional posterior-stabilized components with short cemented stems rather than higher invasive and constrained constructs. Methods: This technical note describes a step-by-step surgical workflow using the Mako robotic system (Stryker) to revise failed primary TKA associated with minimal metaphyseal bone loss to rTKA with conventional posterior-stabilized components and short cemented stems within a functional alignment framework. Results: The workflow integrates CT-based three-dimensional planning, registration on in situ implants, real-time gap assessment, and precise robotic bone preparation to correct deformity and to restore stability while minimizing additional bone resection. In this setting, limited tibial metaphyseal defects are managed with impacted autologous cancellous graft, and stable fixation is achieved with short cemented stems. Conclusions: This robotic-assisted approach is intended as a bone-preserving option for selected rTKA cases associated with minimal bone loss and as a conceptual bridge between robotic-assisted primary and conventional revision TKAs performed with mechanical techniques and alignments. Full article

Bone cement implantation syndrome (BCIS) is classically associated with acute intraoperative cardiopulmonary disturbances during cemented arthroplasty. However, accumulating clinical observations suggest that its systemic manifestations may extend beyond the immediate peri-cementation period. Hepatic involvement remains rarely reported and is poorly characterized, particularly in frail elderly patients with limited physiological reserve. We report the case of an 82-year-old woman who developed severe but reversible ischemic acute liver failure with concomitant acute kidney injury following cemented total hip arthroplasty. A brief peri-cementation episode of hypotension and mild hypoxemia was followed, within the early postoperative period, by abrupt elevation of aminotransferases (AST 4980 IU/L; ALT 3120 IU/L), coagulopathy (INR ≥ 1.5), transient neurological alteration compatible with early hepatic encephalopathy, severe acute kidney injury, and new-onset atrial fibrillation. An extensive diagnostic evaluation excluded viral, autoimmune, toxic, biliary, vascular, infectious, and structural causes of liver injury. The clinical and biochemical profile was consistent with ischemic hepatocellular injury occurring in the context of systemic hypoperfusion. Management consisted of supportive intensive care focused on hemodynamic stabilization, respiratory support, rhythm control, metabolic management, and close laboratory monitoring, resulting in complete hepatic, renal, and neurological recovery. This case describes a rare presentation of ischemic acute liver failure with multiorgan involvement following cemented total hip arthroplasty. The temporal association with transient peri-cementation hypotension and hypoxemia suggests a possible delayed systemic manifestation within the spectrum of BCIS, even in the absence of overt intraoperative collapse. Although causality cannot be established, the clinical course underscores the importance of careful postoperative evaluation in vulnerable patients who experience perioperative hemodynamic disturbances. Full article

Background and Objectives: The management of periprosthetic tibial fractures distal to revision Total Knee Arthroplasty (TKA) presents a biomechanical challenge, often requiring extramedullary locking plates when long stems preclude nailing. While in femoral fractures the gap between the stem and plate is a well-documented stress riser, requiring implant overlap to prevent an inter-implant fracture, this specific biomechanical scenario has not been studied in the tibia, and it remains unclear if the femoral dogma of mandatory overlap applies to the straight, centrically loaded tibial anatomy. This study utilized Finite Element Analysis (FEA) to evaluate stress distribution in the tibial inter-implant gap. Materials and Methods: A comparative FEA was performed using a validated standardized tibia model simulating a healed distal fracture. Two cemented revision TKA constructs (50 mm and 80 mm stems) were modeled. These were paired with medial locking plates of varying lengths (10, 12, and 14 holes) to create different inter-implant distances. Eight distinct configurations, including non-plated controls, were subjected to physiological axial compression and three-point bending. Outcome measures included von Mises stress and total displacement. Results: The analysis revealed no significant stress concentration in the bone within the inter-implant zone across all plated models, regardless of the gap size. Instead, the addition of plates universally reduced bone stress compared to controls, effectively transferring load to the fixation hardware. Peak stresses were consistently observed in the proximal locking screws rather than the bone gap. The longest plates (14 holes) offered superior construct rigidity and stress distribution. Conclusions: Under the conditions evaluated in this preclinical finite element model, the tibia does not exhibit a biomechanical requirement for implant overlap to prevent stress risers. Our findings suggest that extramedullary fixation with the longest available anatomical locking plate represents a biomechanically plausible strategy for these fractures, even if an inter-implant gap remains. Full article

Background/Objectives: Successful cementless total knee arthroplasty (TKA) requires adequate bone quality. However, reliable tools for intraoperative assessment remain limited. This study aimed to introduce a novel visual grading system for evaluating femoral bone during surgery and to assess its correlation with actual bone mechanical properties and suitability for cementless fixation. Methods: We prospectively recruited 193 patients receiving posterior-stabilized TKA. Intraoperatively, femoral cutting surfaces were classified into four visual grades (Excellent, Good, Fair, Poor) considering pore appearance and contour integrity. Femoral bone specimens were harvested during box preparation, and bone mechanical properties were measured through indentation testing. Spearman correlation was used to evaluate the relationship between visual grades and bone mechanical properties. Fisher’s exact test was used to evaluate the distribution pattern of cementless suitable and cemented mandatory classifications across visual grading. Receiver operating characteristic (ROC) analysis was used to evaluate diagnostic accuracy for each visual grade cutoff. Results: Visual grade strongly correlated with bone mechanical properties (Spearman’s ρ = 0.881, p < 0.01). Cementless suitable cases were predominantly distributed in Good/Excellent visual grades, while cemented mandatory cases were mostly found in Fair/Poor grades. However, 8% of Good visual grade specimens exhibited strength warranting cemented fixation, and 18% of Fair visual grade specimens demonstrated adequate mechanical properties for cementless fixation. Using the Good visual grade as a cutoff threshold, ROC analysis showed excellent diagnostic accuracy (AUC = 0.941) with high sensitivity (89%) and specificity (94%). Conclusions: The authors’ novel intraoperative visual assessment system demonstrated significant correspondence to measured bone mechanical properties in the distal femur and showed high accuracy in determining suitability for cementless TKA in Asian individuals. Given the ethnic homogeneity of this cohort, further validation in diverse populations is required to generalize these findings. Full article

Mineral trioxide aggregate (MTA) is a calcium silicate-based endodontic biomaterial widely used for its biocompatibility, sealing ability, and osteoconductive potential; however, further enhancement of its bone regenerative capacity without compromising structural stability remains of interest. Strontium apatite (SrAp), a bioactive calcium phosphate phase structurally analogous to bone mineral, may promote osteogenic activity and bone regeneration. In this study, standardized cylindrical defects (2.5 mm diameter, 4 mm depth) were created in the right tibial metaphysis of systemically healthy rats and allocated to four groups: empty defect (control), pure MTA, 25SrAp–MTA, and 50SrAp–MTA. SrAp nanoparticles were synthesized hydrothermally and incorporated into the MTA matrix at predefined weight fractions. Materials were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). After 8 weeks, tibial specimens were harvested and processed for H&E histology; fibrous tissue formation, new bone formation, and osteoblastic cell presence were semi-quantitatively scored. XRD and FT-IR confirmed that SrAp incorporation preserved the fundamental Ca-silicate phase architecture and hydration chemistry of MTA, indicating chemical and crystallographic stability. SEM–EDX demonstrated progressive microstructural densification with increasing SrAp content, with reduced intergranular porosity and homogeneous SrAp distribution. Histologically, both SrAp–MTA groups exhibited significantly higher new bone formation and osteoblastic activity than untreated controls (p < 0.05), while fibrotic tissue formation did not differ significantly among groups. Although SrAp–MTA composites did not show statistically significant superiority over pure MTA after multiple-comparison adjustment, they demonstrated consistent osteogenic trends relative to empty defects. Overall, SrAp reinforcement yields a chemically compatible and structurally stable MTA-based composite that supports an enhanced osteogenic response in vivo without increasing fibrosis, suggesting potential utility in endodontic surgery and bone defect repair; longer-term and quantitative analyses are warranted to optimize SrAp content and confirm long-term performance. Full article