Prosthesis, Volume 7, Issue 3 (June 2025) – 19 articles

Background: Finger orthoses are essential for treating injuries, deformities, and disorders of the upper limbs by supporting, immobilizing, or correcting deformities. Recent advances in three-dimensional (3D) printing have significantly enhanced precision and customization compared to traditional fabrication methods such as thermoplastic molding, plaster or fiberglass casting, and the use of prefabricated splints. Methods: The present review was conducted using PubMed, Scopus, and other databases with keywords such as “hand therapy”, “additive manufacturing”, “finger and thumb”, and “orthosis”. Only English-language publications were considered, with a primary focus on articles published between 2010 and 2025. Key themes were identified and categorized into conditions necessitating finger orthoses, types and classifications, ergonomic design considerations, and advancements in additive manufacturing. Results: Finger orthoses address musculoskeletal injuries, inflammatory diseases, and neuromuscular disorders. Three-dimensional printing provides enhanced customization, reduced material waste, rapid prototyping, and the ability to create complex geometries, improving patient comfort and functionality. Conclusions: Finger orthoses effectively treat various conditions by supporting and stabilizing fingers. A thorough understanding of anatomy, biomechanics, and fabrication methods is crucial for achieving functional and comfortable designs. Three-dimensional printing offers a transformative approach to producing lightweight, customizable, and cost-effective orthoses, enabling innovative and personalized solutions. By bridging clinical needs and design strategies, this review may guide future innovations in patient-specific orthotic development. Full article

Background/Objectives: Semi-active prosthetic feet present a promising solution that enhances adaptability while maintaining modest size, weight, and cost. We propose a semi-active Two-Keel Variable-Stiffness Foot (VSF-2K), the first prosthetic foot where both the hindfoot and forefoot stiffness can be independently and actively modulated. We present a model-based analysis of the effects of different VSF-2K settings on prosthesis characteristics and gait metrics. Methods: The study introduces a simulation model for the VSF-2K: (1) one sub-model to optimize the design of the keels of VSF-2K to maximize compliance, (2) another sub-model to simulate the stance phase of walking with different stiffness setting pairs and ankle alignment angles (dorsiflexion/plantarflexion), and (3) a third sub-model to simulate the keel stiffness of the hindfoot and forefoot keels comparably to typical mechanical testing. We quantitatively analyze how the VSF-2K’s hindfoot and forefoot stiffness settings and ankle alignments affect gait metrics: Roll-over Shape ($ROS$), Effective Foot Length Ratio ($EFLR$), and Dynamic Mean Ankle Moment Arm ($DMAMA$). We also introduce an Equally Spaced Resampling Algorithm (ESRA) to address the unequal-weight issue in the least-squares circle fit of the Roll-over Shape. Results: We show that the optimal-designed VSF-2K successfully achieves controlled stiffness that approximates the stiffness range observed in prior studies of commercial prostheses. Our findings suggest that stiffness modulation significantly affects gait metrics, and it can mimic or counteract ankle angle adjustments, enabling adaptation to sloped terrain. We show that $DMAMA$ is the most promising metric for use as a control parameter in semi-active or variable-stiffness prosthetic feet. We identify the limitations in $ROS$ and $EFLR$, including their nonmonotonic relationship with hindfoot/forefoot stiffness, insensitivity to hindfoot stiffness, and inconsistent trends across ankle alignments. We also validate that the angular stiffness of a two-independent-keel prosthetic foot can be predicted using either keel stiffness from our model or from a standardized test. Conclusions: These findings show that semi-active variation of hindfoot and forefoot stiffness based on single-stride metrics such as $DMAMA$ is a promising control approach to enabling prostheses to adapt to a variety of terrain and alignment challenges. Full article

Background: As the rehabilitation of the upper anterior maxilla primarily requires high predictability of successful aesthetic outcomes, procedures of immediate implant placement are frequently employed. The aim of this pilot study was to retrospectively evaluate the short-term outcomes of a protocol of immediate implant placement in fresh extraction sockets, followed by immediate non-functional provisional restorations. Methods: Patients were treated for the replacement of maxillary central or lateral incisors, or cuspid teeth with a single-crown locking-taper implant. Clinical and photographic records were retrospectively compared between the teeth prior to extraction (T0) and restorations one year after prosthetic loading (T1). Outcomes were analyzed using the Pink Esthetic Score (PES), according to the patient’s phenotype (thin/thick), with or without the use of connective tissue graft (CTG). Results: The overall mean PES of 25 implants treated was 9.24 ± 2.36 at T0 and 9.60 ± 1.70 at T1. Comparison of groups between T0 and T1 revealed significant PES variations (p = 0.04), with the best and the worst scores, respectively, registered for thin + CTG group (from 7.50 ± 1.91 to 9.75 ± 2.87) and thin group (from 11.33 ± 2.33 to 10 ± 0.89); moderate increases were assessed for thick group (from 8.44 ± 2.40 to 9.44 ± 2.12) and thick + CTG group (from 9.50 ± 1.04 to 9.33 ± 0.81). Conclusions: Within the limits of a short-term analysis of a small number of patients, immediate implant rehabilitation for aesthetic areas of the upper maxilla can be assumed as a safe and predictable protocol. Concomitant use of CTG seems to provide beneficial effects in thin phenotypes, not any additional value in thick phenotypes. Full article

Background/Objectives: The stability of dual mobility (DM) total hip arthroplasty (THA) is often attributed to reduced impingement incidence and a superior range of motion (ROM) compared to the corresponding values when standard implants are used. However, few studies have directly explored this. Thus, the purpose of the present study was to compare the incidence of impingement and the range of motion between standard and DM acetabular cups, whose diameters are suited to the same patient anatomy. Methods: One standard and two DM implants were virtually implanted into a pelvis using a previously developed geometric model. Joint motions, which were representative of seven dislocation-prone activities of daily living (ADLs), as well as walking, were applied to each device type at a range of cup orientations (inclination/anteversion). Conclusions: There were no placement positions that avoided impingement across all seven ADLs, regardless of cup construct type. A similar impingement incidence and ROM were observed for standard and DM constructs, although the consequences of impingement are potentially more serious for DM devices (metal–metal contact) than for standard constructs (metal–polyethylene contact). This finding contradicts the common notion that DM-THAs have a reduced impingement incidence and superior ROM, instead suggesting that their stability may be attributed to alternative mechanisms, such as increased jump distance. Full article

Background: Wettability of dental implant surfaces is a key factor in the osteointegration process. This study aimed to evaluate the effect of a new hydrophilic surface on implant stability in posterior maxilla rehabilitations. Materials and Methods: A 6-month, single-center, parallel-group clinical trial following STROBE guidelines was reported. Implant Stability Quotient (ISQ) changes were compared between implants with a moderately rough surface (MultiNeO CS, Alpha-Bio Tec, Israel, Control Group–CG) and those with the same surface and, in addition, nano-scale roughness and hydrophilic properties (MultiNeO NH CS, Alpha-Bio Tec, Israel, Test Group–TG) placed using a crestal sinus lift technique. ISQ values at bucco-lingual (ISQBL) and mesio-distal (ISQMD) sides were measured at insertion (t0), 4 months (t4), and 6 months (t6). Repeated measures ANOVA (RMA) was performed for statistical evaluation. Results: The study included 35 participants (18 TG, 17 CG). Mean ISQBL0 was 69.45 (SD = 12.62), increasing to 71.72 (SD = 6.74) at t4 and 75.21 (SD = 4) at t6. ISQMD0 mean was 67.54 (SD = 12.54), rising to 72.32 (SD = 6.90) at t4 and 75.67 (SD = 4.60) at t6. No statistically significant differences were found between groups, though TG showed a significant increase in ISQBL at t6 vs. t4 and ISQMD at t6 vs. t0. One-way ANOVA revealed no significant variations between mean ISQ differences over time. Conclusion: Both groups exhibited an increasing ISQ trend, but no significant differences were observed between t4–t0 and t6–t4 periods. Further research is required to assess the impact of hydrophilia on early loading, osteointegration, and long-term outcomes. Full article

Background/Objectives: In the oral environment, tooth-colored restorations are frequently exposed to staining agents, affecting their aesthetic and physical properties. This study assessed the impact of stains and bleaching agents on the surface roughness, microhardness, and color stability of four different composite materials (Omnichroma, Charisma, Z350, and TPH). Methods: Based on group distribution, the discs of all the composite material samples were prepared. All the ninety-six-disc specimens (n = 96) were then randomly divided into four different groups based on different composite resin groups. The samples were then immersed into four different immersing media [each group had twenty-four-disc samples (n = 24)]. Finally, all the samples then faced the challenge of a bleaching agent application. Measurements were taken at baseline, post-immersion, and post-bleaching stages. Results: Red wine caused increased roughness in Filtek™ Z350 and significant color change in Omnichroma, while coffee increased roughness in Omnichroma and altered the color of TPH spectra. Soda led to increased roughness and significant color change in TPH spectra. Additionally, Filtek™ Z350 experienced reduced microhardness across all solutions after bleaching. Conclusion: This study concluded that staining and bleaching adversely affected the tested composites, with increases in surface roughness, color change, and microhardness reduction observed. Overall, Charisma diamond demonstrated the greatest resilience to staining and bleaching challenges, whereas Filtek™ Z350 XT exhibited the most pronounced degradation, indicating that composite formulation critically governs both aesthetic and mechanical stability under clinically relevant conditions. Full article

Objectives: The widespread adoption of three-dimensional (3D)-printed resins in restorative dentistry has introduced significant challenges in establishing strong and lasting bonds with resin-based cements. Despite the development of numerous surface treatment techniques designed to improve adhesion, a clear consensus on the most effective approach remains elusive. This systematic review and meta-analysis critically examined the impact of various surface treatment protocols on the bond strength of 3D-printed resins. By comparing treated versus untreated surfaces, the study aimed to determine the most reliable strategies for enhancing adhesion, ultimately offering evidence-based guidance to inform clinical decision-making. Methods: This review identified relevant studies through a comprehensive search of MEDLINE via PubMed, Web of Science, Scielo, Scopus, and EMBASE databases, supplemented by manual reference checks, to identify in vitro studies published up to February 2025. Studies assessing the bonding of 3D-printed resins following various surface treatments and bonding protocols were included. Data on bond strength outcomes, such as shear bond strength, microtensile bond strength, and microshear bond strength, were extracted. Data extraction included study details, type of 3D-printed resin and printing technology, surface treatment protocols, bond strength testing methods, storage conditions, and results. The quality of included studies was assessed using the ROBDEMat tool. Meta-analyses were performed using the Review Manager Software (version 5.4, The Cochrane Collaboration, Copenhagen, Denmark), with statistical significance set at p < 0.05. Statistical heterogeneity among studies was evaluated using the Cochran Q test and the I² inconsistency test. Results: Nine studies met the criteria for qualitative analysis, with eight included in the meta-analysis. The findings revealed that surface treatment protocols significantly enhanced the immediate bond strength to 3D-printed resins (p = 0.01), with only sandblasting and silane demonstrating a statistically significant effect (p < 0.007). Similarly, after aging, surface treatments continued to improve bond strength (p = 0.01), with sandblasting and hydrofluoric acid being the only methods to produce a significant increase in bond strength values (p < 0.001). Conclusions: This meta-analysis underscores the importance of combining mechanical and chemical surface treatments, especially sandblasting and silane application, to achieve reliable and durable bonding to 3D-printed resins. Full article

Background/purpose: Fiber-reinforced materials are commonly used as biobases beneath indirect restorations, potentially affecting the seating and marginal accuracy of the restorations. This study intended to assess the impact of various biobase techniques on the marginal adaptation of lithium disilicate overlay restorations. Methods: Fifty sound maxillary first premolar teeth of comparable dimensions were prepared using a full-bevel overlay design (3 mm occlusal reduction) and allocated randomly to five groups as follows (n = 10): Group A, delayed dentin sealing; Group B, immediate dentin sealing using Optibond FL; Group C, immediate dentin sealing with a 1 mm flowable composite layer (Clearfil AP-X Flow); Group D, immediate dentin sealing followed by a 1 mm short-fiber-reinforced composite layer (everX Flow); and Group E, immediate dentin sealing coated with a 1 mm flowable composite layer reinforced with polyethylene Ribbond fibers. Digital impressions were obtained using a Medit i700 intraoral scanner, and the overlays were digitally designed via the Sirona inLab CAD software and milled via a four-axis milling machine. The overlays were luted with a preheated composite (Clearfil AP-X). Marginal gap assessments were conducted pre- and post-cementation via a digital microscope at 230× magnification. The data were statistically analyzed using a one-way analysis of variance and paired t-tests. Results: The one-way ANOVA disclosed no significant differences among the groups before or after cementation (p > 0.05). Conclusions: The presence or absence of fiber-reinforced biobases did not impact the marginal adaptation of the restorations; these biobases can be incorporated to optimize the mechanical behavior of indirect restorations without adversely affecting their seating accuracy. These findings suggest that fiber-reinforced and non-reinforced biobase techniques can be safely integrated into clinical adhesive protocols to enhance the mechanical performance of restorations without comprising their marginal adaptation. Full article

Background/Objective: Changes in limb volume affect prosthetic socket fit and limb health, which in turn affects the comfort, stability, and usability of a prosthesis. The objective of this research was to identify and evaluate residual limb fluid volume metrics that could be used to identify the need for a prosthetic socket modification or replacement. Methods: A prospective observational study was conducted with transtibial prosthesis users undergoing socket modification or replacement. Participants performed a morning and afternoon 20 min structured activity protocol and self-reported their average socket comfort and other health outcomes before and after their socket was modified or replaced. Limb fluid volume changes across the protocol were recorded using bioimpedance analysis. Results: Anterior region residual limb fluid volume loss was low when the socket comfort score was high. Participants with ESCS_ave increases of ≥2 points pre- to post-modification experienced less limb fluid volume loss post-modification minus pre-modification (mean +0.6%) compared to participants with ESCS_ave increases of <2 points (mean −0.9%) (p = 0.0002). Conclusions: The percentage of fluid volume in the anterior limb may be a useful quantitative metric to explore for the application of bioimpedance monitoring in clinical care, helping to identify when sufficient change has occurred such that a new socket is warranted. Full article

Objectives: Traditional 2D cell cultures on flat surfaces fail to replicate 3D environments, affecting cellular morphology and function. Various 3D techniques (e.g., spheroids, organoids, organs-on-chips, 3D bioprinting) have been used for disease modelling and drug testing, but their application in hard tissues remains challenging. This study aimed to develop a biocompatible 3D culture method for bone tissue organoids using human bone marrow-derived stem cells (hBMSCs) and hydrogels. Methods: hBMSCs were isolated from human jawbone marrow. The control group was cultured under 2D conditions, whereas the experimental group was cultured in a 3D hydrogel environment. In vitro analyses, including flow cytometry and RNA sequencing, were performed. Quantitative data were statistically analysed at a 0.05 level of significance. Results: hBMSCs cultured in 3D hydrogel conditions indicated enhanced reproducibility, increased cell viability, and significant osteogenic differentiation. Genes such as MMP-13, LPL, and SP7 showed substantially higher expression in 3D cultures, with protein-level confirmation by Western blot. These findings suggest that 3D culture more effectively supports the natural growth and differentiation of hBMSCs. Conclusions: Culturing hBMSCs in a 3D environment more closely mimics in vivo conditions, thus promoting the expression and activity of critical proteins involved in hBMSC differentiation. Full article

Background: Nanomaterial-based biosensors represent a transformative advancement in oral health diagnostics and therapeutics, offering superior sensitivity and selectivity for early disease detection compared to conventional methods. Their applications span prosthetic dentistry, where they enable the precise monitoring of dental implants, and theranostics for conditions such as dental caries, oral cancers, and periodontal diseases. These innovations promise to enhance proactive oral healthcare by integrating detection, treatment, and preventive strategies. Objectives: This review comprehensively examines the role of nanomaterial-based biosensors in dental theranostics, with a focus on prosthetic applications. It emphasizes their utility in dental implant surveillance, the early identification of prosthesis-related complications, and their broader implications for personalized treatment paradigms. Methods: A systematic literature search was conducted across PubMed, Scopus, and Web of Science for studies published between 2010 and early 2025. Keywords included combinations of “nanomaterials”, “biosensors”, “dentistry”, “oral health”, “diagnostics”, “therapeutics”, and “theranostics”. Articles were selected based on their relevance to nanomaterial applications in dental biosensors and their clinical translation. Results: The review identified diverse classes of nanomaterials—such as metallic nanoparticles, carbon-based structures, and quantum dots—whose unique physicochemical properties enhance biosensor performance. Key advancements include the ultra-sensitive detection of biomarkers in saliva and gingival crevicular fluid, the real-time monitoring of peri-implant inflammatory markers, and cost-effective diagnostic platforms. These systems demonstrate exceptional precision in detecting early-stage pathologies while improving operational efficiency in clinical settings. Conclusions: Nanomaterial-based biosensors hold significant promise for revolutionizing dental care through real-time implant monitoring and early complication detection. Despite challenges related to biocompatibility, scalable manufacturing, and rigorous clinical validation, these technologies may redefine oral healthcare by extending prosthetic device longevity, enabling personalized interventions, and reducing long-term treatment costs. Future research must address translational barriers to fully harness their potential in improving diagnostic accuracy and therapeutic outcomes. Full article

Introduction: Intertrochanteric femoral fractures (IFFs) are the most common traumatic injuries in elderly people and significantly impact the patient’s health status. The current evidence indicates that short intramedullary nails may be a better choice than dynamic hip screws in IFF management, being less invasive and biomechanically superior, providing a buttress to limit fracture collapse. On the other hand, an unstable fracture may collapse even after adequate reduction and fixation. This paper aims to describe the surgical complexity of the nail-to-total hip arthroplasty (THA) conversion, focusing on the restoration of normal hip geometry. Material and Methods: Patients referred to our level I trauma center with failed cephalomedullary nailing following IFFs and managed with the nail-to-THA conversion were retrospectively recruited. The anteroposterior postoperative pelvis radiographs were analyzed to establish whether the normal biomechanics of the involved hip were restored. The following radiographic parameters were recorded and compared to the contralateral unaffected side: hip offset, cervical–diaphyseal angle, and limb length discrepancy. Clinical assessment was performed using the following scores: the Harris hip score (HHS) and the visual analog scale for pain (VAS). The independent samples t-test and the Pearson correlation test were performed. The tests were two-tailed; a p < 0.05 was considered significant. Results: A total of 31 patients met the inclusion and exclusion criteria (10 males and 21 females; mean age: 76.2 years; range: 66–90 years) and were included in this study. The modes of trochanteric nail failure included the following: cut-out in 22 cases (70.97%), non-union in 4 cases (12.9%), peri-implant fracture in 1 case (3.23%), cut-through in 2 cases (6.45%), and femoral head avascular necrosis (HAN) in 2 cases (6.45%). Long stems were used in 21 patients out of 31 (67.74%), while dual-mobility cups were implanted in 24 patients out of 31 (77.41%). A significant mean neck shaft angle (NSA) increase (p < 0.001) and a significant mean femoral offset reduction (FO, p 0.001) compared to the contralateral hip were recorded; a mean limb length discrepancy (LLD) of 8.35 mm was observed. A significant correlation between HHS and ∆NSA (p = 0.01) and ∆FO (p = 0.003) was recorded. Conclusions: Conversion from a cephalomedullary nail to THA is a complex procedure that should be considered a revision surgery, rather than a primary surgery. Surgeons must be aware that normal hip geometry may not be obtained during this surgical procedure; thus, a patient undergoing the nail-to-THA conversion for intertrochanteric fixation failure may have an increased risk of implant-related complications. Full article

Background/Objective: Research indicates that sport is a useful avenue in rehabilitation for redeveloping identity for people with a limb amputation. However, the available research focusses on Paralympians or elite athletes with disabilities. By contrast, this study aimed to explore the experience of sport participation and identity in lay members of the public who had undergone limb amputation. Methods: Semi-structured interviews took place with nine people who had undergone amputation and participated in sport. The interviews were recorded, transcribed, and analysed using interpretative phenomenological analysis. Results: Four themes were developed from the data: (1) enabling a feeling of normality and equality; (2) becoming a better person; (3) belonging and connection; and (4) experiencing and responding to the gaze of others. The findings highlight the role of sport in facilitating personal growth through a desire to help and inspire others. Conclusions: Rehabilitation professionals involved in care following amputation could offer person-centred therapies to those who may be reluctant to participate in sport in a way that makes use of a person’s values and facilitates personal growth. Full article

Background/Objectives: Using chemical disinfectants to clean the base of heat-cured acrylic dentures has several negative effects, including toxicity. On the other hand, therapeutic herbs have fewer adverse effects. This study intended to determine how the antibacterial efficacy and the surface roughness of the heat-cured acrylic material used to fabricate dentures were affected by the use of Cordia myxa fruit (CMF) extract as a disinfection solution for dentures using the immersion technique. Methods: Heat-cured acrylic specimens were prepared (N = 110; 55 specimens) for each test; each group contained five specimens. Three CMF extract concentrations (50, 100, and 150 mg/mL) were made and examined for three immersion times (5, 10, and 15 min). The results were compared to the first control group, which used distilled water, and the second group, which used 2% glutaraldehyde for ten minutes, in accordance with the guidelines. One way analysis of variance ANOVA and Games–Howell post hoc test were employed in SPSS (Statistical Package for the Social Sciences) program for statistical analysis. Results: The results for the antibacterial test revealed that CMF solutions had a statistically significant difference in all test groups in comparison with the first control group and non-significant differences with (H p = 0.92; J p = 0.278; K p = 0.303) groups in comparison with the second control group (Glutaraldehyde 2%). For the surface roughness test, the effect was not statistically significant for all groups compared to the first and second control groups. Conclusions: It can be concluded that immersing the heat-cure acrylic samples in a solution of 100 mg/mL CMF extract for 15 min, and 150 mg/mL for 10 and 15 min, has an antibacterial effect similar to that of the Glutaraldehyde 2% antiseptic and no negative effect on surface roughness. Full article

Purpose: The aim of this study was to evaluate the color stability of 3D printed resin disks using spectral reflectance data obtained at different time periods after immersion in various staining solutions. The color stability of 3D-printed temporary crowns is clinically important, as it directly affects the esthetic outcome and patient satisfaction during the provisional phase of treatment. Materials and methods: Forty identical round disk specimens measuring 10 mm in diameter and 2 mm in thickness were fabricated using CAD/CAM 3D printing resin (shade B1). Half of the specimens (n = 20) were polished using an acrylic bur and medium pumice. The remaining specimens were unpolished (n = 20). Each group of disks was then immersed in one of the following immersion solutions: artificial saliva, black tea, carrot juice, and red wine. Color difference ΔE was evaluated using the spectrophotometer, a spectral reflectance instrument, at baseline, day 1, week 1, week 2 and week 3, against a white background. Comparisons between polished and unpolished disks at each time point were conducted using Mann–Whitney tests. Differences among the staining solutions at each time point for both polished and unpolished disks were analyzed using a one-way ANOVA with Tukey’s post hoc test. Results: Color difference ΔE was measured using the CIELAB formula. The mean ΔE values of each group were calculated. The greatest difference in color was observed in the unpolished and polished disks immersed in red wine. Polished disks showed less color difference when compared to unpolished disks. Significant differences in ΔE were detected between polished and unpolished disks immersed in red wine at week 1 (p = 0.0159), week 2 (p = 0.0079) and week 3 (p = 0.0079) and in carrot juice at week 3 (p = 0.0317). Conclusions: Immersion of 3D printed disks in different staining solutions caused detectable color difference in the tested materials, which was relative to the immersion duration and the staining solution used. The color of the 3D printed resins is influenced by the surface finishing, which may result in visually perceptible color differences. The color stability of 3D printied materials should be improved to provide long-term esthetics. Full article

Purpose: The aim of this study was to evaluate the long-term clinical results of two different implant–abutment connection types (screw-retained/Morse locking taper), marginal bone loss, and complications in prosthetic restorations. Materials and Methods: In 2017–2018, 579 implants and 242 implant-supported restorations applied to 137 patients were included in the study. Patients were recalled every six months, clinical evaluations were accomplished, and complications were recorded. When examining the distribution of prosthetic restorations by type, it was determined that 38 (15.70%) were single crowns, 136 (56.19%) were fixed partial cement-retained bridge restorations, 53 (21.90%) were fixed partial screw-retained bridge restorations, and 15 (6.19%) were overdenture prostheses. Findings: Overall, complications included eighteen (21.68%) retention losses, nineteen (22.89%) instances of screw loosening, twenty-one (25.30%) veneer ceramic fractures, three (3.61%) acrylic base fractures, fourteen (16.87%) cases of peri-implantitis, and eight (9.64%) implant losses. Conclusions: Differences in complication rates were observed between implants with different implant–abutment connection designs. While no significant differences were found regarding annual mesial and distal marginal bone loss for implants with conical locking connections, a significant difference was detected in those with screw-retained connections. In both implant groups, mesial and distal marginal bone loss progressed gradually over the follow-up period. Full article

Background: Total hip arthroplasty (THA) is a widely adopted surgical intervention for restoring mobility and reducing pain in patients with severe hip joint conditions, such as osteoporosis. However, traditional titanium implants often lead to stress shielding and subsequent bone resorption due to the mismatch in stiffness between the implant and bone. Objectives: This study computationally investigates the biomechanical performance of femoral implants made from composite materials, specifically polyether-ether-ketone (PEEK) and polylactic acid (PLA) reinforced with hydroxyapatite (HA), compared to conventional titanium stems. Methods: Using finite element (FE) modeling, physiological loading during walking was simulated, and the strain energy density (SED) was analyzed to assess stress distribution and the potential for stress shielding across different Gruen zones. Results: The results indicate that both the PEEK and PLA composites exhibited more physiological load transfer, particularly in Gruen zones 1 and 7, reducing stress shielding and supporting bone preservation. Conclusions: These findings suggest that PEEK and PLA composites may offer improved implant stability and bone integration. Despite highlighting the promise of biomimetic materials in orthopedics, this study is limited to computational analysis and requires experimental validation. It emphasizes the need for further investigation using patient-specific geometries and a variety of loading scenarios to confirm these benefits and optimize femoral implant design. Full article