Osteology

Background/Objectives: The anatomical variability of the human foot represents a subject of substantial interest, offering valuable insights in anthropological research as well as in clinical practice. The aim of this study is to document anatomical variants of the tarsal bones in a CISC//XXI skeletal sample (21st Century Identified Skeletal Collection), with a particular focus on the prevalence of accessory ossicles. Methods: The studied sample consisted of 163 individuals (83 females and 80 males). The prevalence of six accessory tarsal bones was recorded (os trigonum, calcaneum secundarium, the accessory navicular bone, os sustentaculum, os vesalianum and os intermetatarseum). Results: A total of 35 individuals (21.4%; 35/163) exhibited at least one accessory ossicle, with 13 females (15.7%; 13/83) and 22 males (27.5%; 22/80). The os trigonum and calcaneum secundarium were the most frequently observed accessory bones, respectively, in 9.3% (15/162) and 6.9% (11/159) of the individuals. No sex differences were observed. All accessory bones occurred more frequently unilaterally, and no co-occurrences of accessory bones were observed. Conclusions: These findings are crucial in both the biomedical and anthropological fields, where a detailed knowledge of foot anatomy and its variations is relevant. Full article

Background/Objectives: Magnetic resonance arthrography is the reference standard for evaluating glenoid labral lesions. Deep learning (DL) reconstruction algorithms may accelerate 3D acquisitions while maintaining image quality. This study assesses the diagnostic accuracy of DL-based isotropic 3D MR imaging for detecting glenoid labral lesions. Methods: This prospective study included 128 consecutive patients (79 men, 49 women; mean age 38.4 years) undergoing shoulder MR arthrography between June 2023 and April 2025. DL-based 3D sequences (acquisition time: 3:26) were compared with conventional multiplanar TSE and PD-FS sequences (acquisition time: 24–28 min). Two independent radiologists assessed glenoid labral lesions, bone marrow edema, and rotator cuff abnormalities using a four-point Likert scale. Sensitivity, specificity, and interobserver agreement were calculated. Results: DL-based 3D sequences demonstrated 94.7–95.1% sensitivity and 100% specificity for glenoid labral lesions, with excellent interobserver agreement (κ = 0.812). The area under the ROC curve was 0.894. Combined 3D protocols (T1 + PD-FS) showed superior accuracy (97.8%) compared to single sequences (90.5%, p = 0.012). For bone marrow edema, sensitivity was 82.9% with 100% specificity. Rotator cuff evaluation achieved 75% sensitivity with 100% specificity. Conclusions: DL-based isotropic 3D sequences provide high diagnostic accuracy for glenoid labral pathology while reducing scan time by 75%. Combined T1 and PD-FS protocols optimize performance. These findings support selective implementation of DL-accelerated 3D protocols in shoulder MR arthrography, particularly for labral assessment, while acknowledging that conventional protocols may remain preferable in specific clinical scenarios. Full article

Background: The present case report study aims to describe, from both clinical and histological aspects, the bone healing pattern in a patient under oral bisphosphonates therapy. Case Presentation: an 82-year-old female patient has been under oral nitrogen bisphosphonates therapy for two years. She underwent a tooth extraction. After four months, two bone biopsies were harvested, during standard implant drilling procedures. The first one corresponded to the healed alveolar socket of the previously extracted tooth (specimen A), while the second one corresponded to the bone ridge that was edentulous before starting the bisphosphonates therapy (specimen B). Morphometric and histologic analyses were performed. Results: In both, the bone resulted vital and no evidence of empty lacunae was detected. A reduction in the haversian canal diameter was observed in specimen B. The present case report highlights histological findings suggesting that patients undergoing oral bisphosphonates therapy may be eligible for surgical therapy. A pre-operative careful anamnesis and the observance of international guidelines for treating patients taking bisphosphonates are mandatory. Conclusions: These preliminary results will be used to plan a large clinical study in order to better understand the influence of bisphosphonates on the bone healing process. Full article

Bone remodeling is a dynamic process involving bone resorption and formation that is regulated on a cellular level and impacted by mechanical stress. A variety of Orthopedic surgery treatment strategies can affect bone remodeling, which can in turn may have long-term impacts on skeletal stress tolerance and function. This review provides a comprehensive overview of bone remodeling involved in Orthopedic surgery. Materials related to bone remodeling principles across Orthopedic surgery domains were selected and compiled using databases including PubMed, MEDLINE, AccessMedicine, and CINAHL; case studies were not included. Relevant literature was summarized for a general review of bone remodeling and as it relates to treatment principles in trauma, arthroplasty, and amputation with the aim of providing a relevant, comprehensive review. Overall, the purpose of this review is to provide an overview of bone remodeling principles that are implicated in various techniques within Orthopedic surgery. Full article

Background: Low peak bone mass (PBM) is a major contributor to later osteoporosis risk. This study sought to understand young people’s knowledge of factors associated with bone health. Methods: Young people in Aotearoa New Zealand were approached. Eight focus groups (26 participants in total, aged 11 to 17 years) were conducted using a semi-structured approach with open-ended questions and prompts. Transcripts were thematically coded using an inductive content analysis approach. Results: Knowledge of factors associated with good bone health was limited. There was a general awareness of the positive and negative impacts of many lifestyle behaviours on health generally, but not specifically PBM. Dairy intake was commonly mentioned as being beneficial for bone health. Some participants reported potential benefits of sport, but most did not know that weight bearing activity specifically was beneficial. Conclusions: Knowledge of osteoporosis and lifestyle factors that impact PBM was limited. Educational interventions involving promotion of bone health knowledge and supporting weight bearing physical activity in adolescents may be an important contributor to public health strategies. Full article

Background/Objectives: To determine whether patients under 30 years of age who have experienced symptoms for a duration of less than 1 year before undergoing hip arthroscopy (HA) for femoracetabular impingement (FAI) have better patient-reported outcomes than patients aged 40 years or older who have experienced symptoms for a duration of more than 1 year. Methods: This is a single-center, single-surgeon, retrospective analysis performed between August 2007 and May 2023 analyzing patients who underwent hip arthroscopy. Patients were divided into those who were 18 to 30 years old and patients that were 40 years and older. All patients who underwent primary hip arthroscopy for FAI and had completed mHHS or NAHS surveys prior to surgery with at least a 2-year follow-up were initially included in the study. Patients were excluded if they had no symptom duration information documented in their electronic medical record, a history of inflammatory arthritis, previous ipsilateral hip surgery, or future conversion to total hip arthroplasty (THA) before final follow-up. Results: A total of 236 hip arthroscopies were analyzed, including 147 patients ≥40 years and 89 patients 18–30 years, with symptom duration being significantly longer in the older cohort (28.4 vs. 17.5 months, p < 0.001). At 2 years, there was no difference in mHHS or NAHS between groups; however, younger patients with shorter symptom duration were more likely to achieve PASS for NAHS (87.5% vs. 58.7%, p = 0.036). At 5 years, the older cohort showed greater improvement in mHHS (33.1 vs. 22.9, p = 0.048), while patients 18–30 years continued to demonstrate higher absolute mHHS and NAHS at both 2 and 5 years. Regression analysis confirmed that increasing age was associated with lower PROs at follow-up. Conclusions: There was a significantly greater number of patients who achieved PASS for NAHS at 2-year follow-up for patients who were 18–30 years old with symptom duration ≤ 1 year compared to those aged 40+ years old with symptom duration ≥ 1 year. Additionally, patients ≥40 years old experienced a significantly longer symptom duration before surgery and had worse outcomes for mHHS and NAHS at 2- and 5-year follow-up compared to the 18–30 year cohort. Full article

Background/Objectives: Charcot-Marie-Tooth (CMT) disease, the most common hereditary peripheral neuropathy, often causes cavovarus foot deformity in children. Surgical interventions to correct deformity or improve function can involve either primary fusion or reconstruction. However, the optimal surgical approach remains contested. This systematic review aims to present and evaluate existing data on both fusion and reconstruction surgical interventions in treating pediatric CMT cavus foot. Methods: A PRISMA-guided search of five electronic databases was conducted (from inception to 17 February 2025). Studies were eligible if they reported surgical outcomes for CMT pediatric patients ($\le$18 years) with cavovarus foot treated by primary fusion or reconstruction. Titles, abstracts and full texts were screened by four independent reviewers, and data were extracted on patient demographics, procedures, follow-up, functional scores, radiographic correction and complications. Results: Fourteen studies met inclusion criteria, encompassing 169 patients and 276 feet, with a mean age at surgery of ~13.5 years. Nine studies evaluated joint-sparing reconstruction, three assessed primary fusion, and two combined both reconstruction and fusion. Both interventions yielded improved outcomes post-operatively. Reconstruction generally produced high patient satisfaction and near-normal radiographic parameters but carried recurrence or reoperation rates of 10–40%. Fusion provided durable correction of rigid deformities but was associated with nonunion, adjacent joint arthritis and higher revision rates. Conclusions: Joint-sparing reconstruction is an effective first-line approach for flexible cavovarus deformities in pediatric CMT patients, while fusion should be reserved for severe, rigid or recurrent cases. A patient-specific staged approach is recommended, and higher-quality comparative studies are needed to refine surgical decision-making. Full article

Background: Risk factors, including Joint Index Vector (JIV), a new disease activity indicator based on three-axis coordinates, and a pain score using a visual analog scale (PS-VAS), were evaluated for incident bone fragility fractures (inc-BFF) in patients with rheumatoid arthritis (RA) in a retrospective case–control study. Methods: RA patients who were followed for at least two consecutive years (RA) and a control group consisting of patients without RA but with similar background demographics (non-RA) were recruited and monitored. The prevalence of inc-BFF was compared between the two groups. Common potential risk factors in both groups and RA-specific factors within the RA group regarding inc-BFF were analyzed statistically. Results: A total of 278 patients were studied in each group. There was no significant difference in the prevalence of inc-BFF between the two groups. Presenting RA was not a major factor in developing inc-BFF. Higher Vz in the JIV, which reflects the difference in the involvement ratio between large and small joints, and higher PS-VAS showed significantly higher hazard ratios in a univariate model. Vz > 0.01, PS-VAS ≥ 25.5, and simplified disease activity index ≥ 2.11 at follow-up, along with PS-VAS at baseline > 21.0, are the key cutoff indices for RA-specific risk factors. When two of these factors were combined, the combination of Vz and PS-VAS at follow-up resulted in the highest hazard ratio (4.25; p < 0.001). Conclusions: These results suggest that combining Vz and PS-VAS is the key risk indicator for inc-BFF. Full article

Objectives: The aim of this study was to determine the epidemiological characteristics of bicycling-related maxillofacial fractures in a defined population and to identify factors contributing to these injuries. Methods: An 8-year cohort study was carried out, including all patients presenting with bicycling-related maxillofacial fractures at a tertiary care center from 2017 through 2024. Data recorded for each patient included age, gender, date and cause of injury, contributing factors, type of facial fractures, other injuries, hospital stay, and helmet use. Statistical analysis was performed. Continuous variables were assessed for normality (Shapiro–Wilk test) and compared using the Mann–Whitney test. Categorical variables were analyzed with chi-square tests. A p-value ≤ 0.05 was considered statistically significant. Results: Out of 899 cycling accident patients seeking medical treatment, 122 (13%) sustained facial fractures, accounting for 4% of all facial fracture cases in our department during the study period. In our cohort, the male–female ratio was 2.6:1, and the mean age was 29.5 years (SD 12.8, range 13–77). Collision with another object/vehicle was the most common cause (64%), followed by isolated falls (36%). A total of 135 facial fractures were recorded (some patients had multiple fractures). Mandibular fractures were most frequent (49% of patients), followed by zygomatic (32%), orbital (13%), nasal (7%), maxillary (2%) and frontal (2%) fractures. Among mandibular injuries, condylar fractures were the most common subtype (63%). Dental injuries were found in 27% of patients. The most common dental trauma was tooth fracture (43% of those with dental injuries), followed by tooth luxation (32%) and tooth avulsion (25%). In 80% of cases involving dental injuries, the upper anterior teeth were involved. Concomitant injuries were present in 20% of patients, most often orthopedic limb injuries. Only 27% of patients reported always wearing a helmet, whereas 43% reported never having worn one. Conclusions: Bicycling-related facial injuries are a noteworthy subset of facial trauma. Missed or delayed diagnosis can lead to lasting deformities and functional issues. Preventive strategies—especially promoting helmet use and improving helmet design—along with broader safety measures are important to reduce the incidence and severity of these injuries. Full article

The present study aimed to determine the acute effects of high-intensity dynamic resistance training (HI-DRT) and whole-body electromyostimulation (WB-EMS) on markers of bone formation and resorption in young healthy women. Using a crossover design, 17 students of dentistry (26.5 ± 4.0 years, 21.5 ± 2.5 kg/m²) were randomly assigned to begin either with HI-DRT (five exercises, three sets to repetition maximum) or 20 min of non-superimposed, low-frequency (85 Hz), intermitted (6 s impulse/4 s impulse break) WB-EMS. The study outcome parameters were total Procollagen Type-1 N-Terminal Propeptide (P1NP) and Type-I Collagen Cross-Linked C-Telopeptide (CTX), which were sampled immediately prior to and 15 min post intervention. ANCOVA was applied to determine the main effects, i.e., differences in pre–post changes in CTX and P1NP between the interventions. No participant was lost to follow-up or reported adverse effects related to the exercises. Briefly, we observed significant differences (p = 0.019, d′ = 1.19) for changes in P1NP that were maintained in the HI-DRT (p = 0.446) and decreased in the WB-EMS group (p = 0.002). In contrast, we did not observe differences for HI-DRT- vs. WB-EMS-induced CTX changes (p = 0.509; d′ = 0.134). In summary, while HI-DRT provides significantly more favorable effects on bone formation markers compared to WB-EMS, the clinical significance of this finding in predicting the general effectiveness of an exercise protocol on bone strength remains to be determined. (Clinical trials.gov; registration date: 2025-02-06; ID: NCT06813092.) Full article

Background: Nutritional status affects bone fragility and related fractures. We investigated the relationships between bone fragility fractures and nutritional indicators, including the Geriatric Nutrition Risk Index (GNRI), Prognostic Nutrition Index (PNI), Control Nutrition Status (CONUT) score, and body mass index (BMI). Methods: Postmenopausal female outpatients aged 75 or older who experienced a hip fracture 2 to 4 weeks ago (hip fracture group; G-HF) or who have no history of hip fracture without secondary osteoporosis but have a T-score of bone mineral density less than −2.5 (primary osteoporosis group; G-POP) were studied using both cross-sectional and longitudinal methods. Variables, including blood test results, T-scores, and nutritional indicators at baseline, were compared between the two groups using a crude dataset and after propensity score matching (PSM). Correlations between hip fracture (HF) and baseline variables were statistically analyzed. The relationship between nutritional indicators and the development of subsequent major osteoporotic fractures (MOFs) after baseline was examined, and the relationship between dietary indicators and functional capacity was also investigated. Results: A total of 1201 patients were recruited from these 113 G-HF and 1088 G-POP groups (crude dataset), of whom 113 were included after PSM. There were many differences between the two groups using the crude dataset. However, no items were significantly different after PSM except for white blood cell count (WBC) and serum phosphorus levels. GNRI < 105.5 demonstrated a typical regression curve regarding prevalent hip fractures. Developing MOF was significantly correlated with T-scores in the femoral neck and the presence of a prevalent fragility fracture. PNI and GNRI demonstrated a significant correlation between functional capacity; however, there was no correlation with the development of MOF. Conclusions: GNRI < 105.5 was significantly correlated with the presence of hip fracture, although no significant association was found with the development of MOF. Full article

Background/Objective: Major research demonstrates that longitudinal loading affects the vertebral growth and disc wedging in the scoliotic animal models; however, there is a scarcity of research on the effect of torque on the vertebral growth. Comparison of the effect of static and dynamic torque on growth is also lacking. The aims of this study were to assess the morphological, histological, and immunohistochemical changes in caudal vertebrae of rats under controlled, static, and dynamic torque. Methods: Adjacent vertebral bodies of female Sprague-Dawley rats were loaded with a torque for 4 weeks. Six rats received a static torque of 1.25 Nm while 6 additional rats received a dynamic torque (2.4 Nm, 1.0 Hz for 15 min/time, 3 times/week). An additional 6 rats formed the control group and received no torque at all. All the rats were later sacrificed, and the tails for histological analysis, immunocytochemistry, and X-rays were obtained. Results: Among the three groups, there were significant differences in right side disc height and average disc height on the proximal vertebrae space in the coronal plane of the X-ray. There were significant differences in the physeal height between static torque and control, or between dynamic torque and control (p < 0.05). The proliferating cell nuclear antigens were detected with variable percentages in samples among the three physeal zones for all groups. Conclusions: Both static and dynamic torque induced asymmetric reduction in the physis and intervertebral disc, which may help to explain the development and vertebral tethering of scoliosis. Full article

Background/Objectives: Osteoporotic vertebral fractures (OVFs) are common in older adults. While surgery is generally reserved for unstable or painful fractures, some OVFs conceal underlying malignancies, including metastatic and hematologic cancers. This study aimed to determine the pooled prevalence of unsuspected malignancy in patients initially diagnosed with OVFs. Methods: A systematic search of PubMed and Scopus was conducted from inception to September 2025 in accordance with PRISMA guidelines. Eligible studies included adults with presumed OVFs who underwent vertebral biopsy and histopathological evaluation. Prevalence estimates were pooled using a random-effects model, and study quality was assessed with the Newcastle–Ottawa Scale. Results: Thirteen studies involving 3513 patients were included. The pooled prevalence of malignancy was 8.0% (95% CI: 5.4–10.6), comprising metastatic solid tumors (4.9%; 95% CI: 2.3–7.4) and multiple myeloma (2.6%; 95% CI: 1.3–3.9). Malignancy was detected in 2.7% (95% CI: 1.8–4.1) of routine biopsy cohorts versus 36.8% (95% CI: 22.1–54.4) of clinically suspected cases. Diagnostic yield exceeded 45% in patients selected by combined history, imaging, or known malignancy. No biopsy-related complications or procedure-related mortality were reported. Moderate heterogeneity was observed, mainly in suspected cohorts. Conclusions: Vertebral biopsy is a safe and diagnostically valuable procedure in vertebral compression fractures. Its yield ranges from about one in 30 patients in routine settings to nearly one in two in high-risk groups, underscoring the importance of structured patient selection to facilitate timely cancer detection and referral. Full article

Background/Objectives: Metallic surgical implants are commonly used in Orthopaedic surgery. There is a paucity of the literature on patient perspectives and awareness regarding their use. This study aims to investigate patients’ self-perceived awareness, knowledge and concerns toward metallic implant usage in Orthopaedic surgery, in order to provide a tailored and efficient means of pre-operative counselling. Methods: A single-centred, cross-sectional questionnaire-based study was performed in a single tertiary centre in Singapore. Patients between 21 and 75 years who were on follow-up with an Orthopaedic surgeon were recruited from the Orthopaedic specialist outpatient clinic. This questionnaire consisted of three main parts. Firstly, patients were asked to grade their self-perceived knowledge on metallic implants on a Likert scale of 1 to 5. The second part included questions designed to determine the level of knowledge of patients on metallic implants. For the third part, patients were asked to grade how comfortable they were with having metal implants in their bodies on a Likert scale of 0 (Strongly Disagree) to 4 (Strongly Agree). Results: A total of 100 patients were recruited, with 56 males and 44 females. The majority of the patients were Chinese (59%), and 32% had tertiary education. The self-perceived awareness regarding metallic implants was low with a median score of 3 (IQR 1–9) (1—unaware, 10—fully aware). There was no significant difference between younger and older patients (>50 years) or between patients of different educational levels. In total, 17% of the participants stated that they preferred to use non-metallic implants. The most significant concerns were surgical costs (51%), post-operation discomfort (50%) and potential rejection of metallic implants (50%). Conclusions: There is a poor level of self-reported awareness on metallic implants and a lack of knowledge regarding the use of metallic implants in Orthopaedic procedures among patients in our local population. The top concerns regarding the usage of metallic implants were cost, adverse reaction to metal and persistent discomfort. A significant percentage of patients prefer to use non-metallic implant options if available. This highlights the need for tailored pre-operative counselling for the provision of information and to address patients’ concerns accurately. Full article

Background/Objectives: Comparison between the 10-year probability of major osteoporotic fracture (MOF) calculated with FRAX (pFRAX) and the actual MOF rate was conducted, and the availability of pFRAX was evaluated with a one-center cohort study. Methods: Eligible patients were followed up for 10 years. Risk factors listed as items in the FRAX, and presence of lifestyle-related diseases (LS-RDs), escalated ability to fall (Fall-ability), cognitive impairment (CI), etc., were evaluated concerning MOF. The 10-year probability and actual MOF rate were compared. Risk factors contributing to the discrepancy between the probability and the actual rate were evaluated after dividing subgroups. Results: The study included 931 patients. Factors that contributed to the significantly higher ratio for incident MOF besides items in the FRAX were LS-RD, Fall-ability, CI, and anti-osteoporotic drug intervention. The higher the number of factors presented, the higher the actual MOF prevalence compared to the probability rise. Presenting LS-RD, Fall-ability, and CI are independent of the items in the FRAX. pFRAX was overestimated in the low-risk groups and underestimated in the high-risk group compared to the actual MOF rate. These phenomena are caused by the lack of consideration of these three comorbidity risks. Conclusions: A discrepancy between pFRAX and the actual MOF rate exists. LS-RD, Fall-ability, and CI should be listed in the items of the FRAX for more concision. Full article

Background/Objectives: Periprosthetic joint infection (PJI) is a challenging problem in orthopedic surgery and is often associated with high morbidity. The treatment becomes even more challenging whenever the microorganism is virulent and/or not widely known as a causative organism on these occasions. This study aims to report on the clinical outcomes of hip hemiarthroplasty prosthetic hip joint infection by an atypical, rare microorganism, Morganella morganii (M. morganii), focusing on morbidity, revisions, and mortality. Methods: This is a retrospective series of four cases of prosthetic joint infections with Morganella morganii, a rare Gram-negative opportunistic facultative anaerobic pathogen, in four patients who received hip hemiarthroplasty for displaced femoral neck fractures at a level 1 trauma center. Clinical notes, laboratory findings, and radiographs were reviewed to extract relevant information regarding the history and outcomes. Results: The patients were four females, with a mean age of 84.27 years at the time of surgery. Two cases (50%) underwent surgical debridement and implant retention, followed by lifelong antibiotic suppression for symptomatic control of persistent wound drainage, and the other two underwent implant removal and resection arthroplasty (one patient) or received an antibiotic spacer (one patient), followed by chronic antibiotic therapy until wound closure. Conclusions: Periprosthetic hemiarthroplasty infection secondary to M. morganii was associated with overall poor outcomes. Antibiotic suppression could be a reasonable option after the surgical debridement or implant removal in M. morganii PJI to control the symptoms. Full article

Background/Objectives: To prevent potential complications for patients with metal hypersensitivity requiring total knee arthroplasty (TKA), implant coatings have been developed. Thermal nitriding of the titanium surface creates a TiN layer that increases hardness and wear resistance while preventing release of cobalt and chromium ions. The aim of this study was to evaluate the clinical safety and performance of an anatomic implant system comprised of thermally nitrided Ti-6Al-4V. Methods: This is an ongoing prospective, multicenter observational cohort study of primary and revision TKA patients. Patient-reported outcome measures including the Oxford Knee Score (OKS), Knee Society Score (KSS) Expectations subscale, EQ-5D-5L, physical exams, and radiographic assessments to document abnormalities were investigated in 94 patients who provided at least two years of follow-up data. The primary endpoint was improvement in the Oxford Knee Score (OKS), defined as the minimal clinically important difference (MCID, 7.0 points). Results: All outcome measures including patient-reported function (OKS) demonstrated significant improvements (19.4–22.6 points) exceeding the MCID with no between-group differences by bearing types utilized. Health-related quality of life as measured by EQ-5D-5L improved over the cohort and was maintained at 2-years post-operative. In total, three (1.4%) radiographic abnormalities were observed, all of which resolved at two-year follow-up. 12 (5.3%) serious complications were reported, none of which were related to the device. Two revisions have occurred, one due to infection and one due to a fall, in the ultracongruent bearing cohort (survivorship 98.1%, 95%CI 87.4–99.7). Implant survivorship was 100% in all other bearing cohorts. Conclusions: This anatomically designed, thermally nitrided titanium alloy implant demonstrated clinically significant improvements in function, PROMs, and quality of life in patients undergoing TKA regardless of bearing type. Excellent two-year implant survivorship between 98.1% and 100% across cohorts were observed, with no radiographic abnormalities at 2 years. Full article

Background/Objectives: Mechanical, physiological, and biochemical changes contribute to post-traumatic osteoarthritis (PTOA). Specific mouse models that are highly reproducible, less invasive, and easy to use are lacking. This limitation hinders the progress of PTOA-related studies on therapeutic applications. The goal of the study was to establish a methodologically innovative, efficient, and less technically challenging surgical model for PTOA. Methods: We developed a modified medial meniscectomy (MMM) model demonstrating high reproducibility and applicability. The MMM model features distinct differences in the execution of transection of the medial meniscus on the lateral side and includes a smaller incision, which enhances reproducibility and is beneficial for studying pain, structure, and function. Results: One month after the MMM surgery, the mice showed increased sensitivity to pain and decreased biomechanical abilities, such as shorter running times and distances. This was further supported by higher Osteoarthritis Research Society International (OARSI) histology scores, a standardized system for determining the severity and extent of OA in cartilage. Additionally, transcriptomic analysis showed an elevated enrichment of immune activity and bone tissue formation gene sets in the knee joint. Conclusions: Overall, functional studies and transcriptomic analyses suggested that the MMM model can be utilized for future biomechanistic and therapeutic applications and could serve as a new resource for studying PTOA. Full article

Background: The long-term success of total knee arthroplasty (TKA) is often compromised by stress shielding, which can lead to bone resorption and even implant loosening. This study employs finite element analysis (FEA) to compare the stress-shielding effects of a knee prosthesis made from polyether ether ketone (PEEK) with a traditional titanium Ti6Al4V implant on an osteoporotic tibial bone model. Methods: Stress distribution and the stress-shielding factor (SSF) were evaluated at seven critical points in the proximal tibia under physiological loading conditions. Results: Results indicate that the PEEK prosthesis yields a more uniform stress transmission, with von Mises stress levels within the optimal 2–3 MPa range for bone maintenance and consistently negative or near-zero SSF values, implying minimal stress shielding. Conversely, titanium implants exhibited significant stress shielding with high positive SSF values across all points. Additionally, stress concentrations on the polyethylene liner were lower and more evenly distributed in the PEEK model, suggesting reduced wear potential. Conclusions: These findings highlight the biomechanical advantages of PEEK in reducing stress shielding and preserving bone integrity, supporting its potential use to improve implant longevity in TKA. Further experimental and clinical validation are warranted. Full article