Aims:To compare outcomes after primary total hip arthroplasty (THA) following prior ipsilateral osteosynthesis with prior ipsilateral osteotomy, and to assess whether femoral fixation modifies risk. Methods:Using the German Arthroplasty Registry (EPRD; 2012 to 2024), two 1:1 matched analyses were performed: prior osteosynthesis versus no prior surgery (8,643 pairs) and prior osteotomy versus no prior surgery (5,569 pairs), matched on age, sex, BMI category, and Elixhauser score. Kaplan-Meier and Cox regression were used, censoring at death, with adjustment for femoral fixation (cemented, cementless, hybrid, reverse-hybrid). Results:After prior osteosynthesis, hazards were higher for revision (HR 6.93 (95% CI 6.07 to 7.92), periprosthetic femoral fracture (PFF; HR 17.22 (95% CI 12.28 to 24.15)), and infection (HR 3.87 (95% CI 3.05 to 4.91)) compared with controls (all p < 0.001); cemented and hybrid fixation had lower revision and PFF hazards than cementless fixation. After prior osteotomy, revision (HR 2.30 (95% CI 1.89 to 2.80)) and dislocation (HR 9.43 (95% CI 4.55 to 19.56)) hazards were higher; PFF and infection were not significant. Reverse-hybrid fixation was associated with higher revision (HR 2.01 (95% CI 1.27 to 3.19)) and infection (HR 3.71 (95% CI 1.71 to 8.06)) hazards than cementless fixation. Conclusion:Prior osteosynthesis denotes a high-risk, conversion-type THA scenario; cemented-based constructs were associated with lower PPF and revision hazards than cementless fixation. Prior osteotomy confers an intermediate risk profile, mainly driven by revision, dislocation, and loosening. Osteosynthesis and osteotomy histories should not be pooled in preoperative risk assessment before THA.

Aims To compare outcomes after primary total hip arthroplasty (THA) following prior ipsilateral osteosynthesis with prior ipsilateral osteotomy, and to assess whether femoral fixation modifies risk. Methods Using the German Arthroplasty Registry (EPRD; 2012 to 2024), two 1:1 matched analyses were performed: prior osteosynthesis versus no prior surgery (8,643 pairs) and prior osteotomy versus no prior surgery (5,569 pairs), matched on age, sex, BMI category, and Elixhauser score. Kaplan-Meier and Cox regression were used, censoring at death, with adjustment for femoral fixation (cemented, cementless, hybrid, reverse-hybrid). Results After prior osteosynthesis, hazards were higher for revision (HR 6.93 (95% CI 6.07 to 7.92), periprosthetic femoral fracture (PFF; HR 17.22 (95% CI 12.28 to 24.15)), and infection (HR 3.87 (95% CI 3.05 to 4.91)) compared with controls (all p < 0.001); cemented and hybrid fixation had lower revision and PFF hazards than cementless fixation. After prior osteotomy, revision (HR 2.30 (95% CI 1.89 to 2.80)) and dislocation (HR 9.43 (95% CI 4.55 to 19.56)) hazards were higher; PFF and infection were not significant. Reverse-hybrid fixation was associated with higher revision (HR 2.01 (95% CI 1.27 to 3.19)) and infection (HR 3.71 (95% CI 1.71 to 8.06)) hazards than cementless fixation. Conclusion Prior osteosynthesis denotes a high-risk, conversion-type THA scenario; cemented-based constructs were associated with lower PPF and revision hazards than cementless fixation. Prior osteotomy confers an intermediate risk profile, mainly driven by revision, dislocation, and loosening. Osteosynthesis and osteotomy histories should not be pooled in preoperative risk assessment before THA. Cite this article: Bone Joint J 2026;108-B(7):880–888.

Periprosthetic joint infection (PJI) is one of the most severe complications in hip arthroplasty, and treatment of PJI is associated with high re-infection rates and significant loss of quality of life for patients, as well as socio-economic impact to health systems. Antimicrobial coating of implants with silver is a promising option to improve the outcome of PJI. However, there is no data from randomized control trials on silver-coated versus standard non-silver-coated implants in patients with PJI. Therefore, the aim of the current study is to assess clinical outcome for the use of silver-coated hip implants (further referred to as IP-coated) versus non-IP-coated implants in patients requiring surgical revision for hip PJI. This is a multicenter confirmatory interventional randomized controlled superiority single-blinded study with two stages: pilot stage (part A) and pivotal stage (part B). Patients indicated for unilateral cementless acetabular and hip stem revision due to chronic periprosthetic infection planned for single-stage or two-stage surgical procedures are included. Patients will randomly be assigned either to the IP-coated or the non-IP-coated implant group. The primary outcome parameter is infection-free survival within 12 months after hip PJI. The underlying hypothesis is that the IP coating significantly reduces the risk of periprosthetic reinfection compared to the non-IP-coated implants. Secondary outcome parameters include data on the safety and performance of the prostheses through a 2-year clinical follow-up, including patient-related outcome parameters, such as Harris Hip Score, EQ-5D, radiographical assessment, and blood silver concentrations. An adaptive study design is planned with the inclusion of 268 subjects according to initial sample size calculations. Upon follow-up of 134 patients for 12 months or inclusion of 90

The hip-spine relationship is increasingly recognized as clinically relevant in patients undergoing total hip arthroplasty (THA), yet associations between THA and changes in low back pain (LBP), sagittal alignment, and functional disability remain incompletely understood. This prospective study evaluated two-year changes in LBP (primary clinical endpoint) and radiographic alignment, with global sagittal alignment and spinopelvic alignment defined as primary radiographic endpoints, as well as their associations with postoperative pain and disability. This prospective observational cohort study included 197 patients undergoing primary unilateral THA. LBP was assessed using the Numeric Rating Scale (NRS) preoperatively and at two-year follow-up. Standing lateral radiographs evaluated global sagittal alignment (sagittal vertical axis [SVA]) and spinopelvic parameters at both timepoints. The Oswestry Disability Index (ODI) assessed postoperative functional disability. Associations between radiographic alignment parameters and clinical outcomes were examined using univariable and multivariable regression analyses. Of 197 patients enrolled, 144 (73.1

Aims:Patients with a history of osteotomy or osteosynthesis pose distinct challenges in total hip arthroplasty (THA) due to altered anatomy and biomechanics. Although THA is an established intervention for degenerative hip disease, limited evidence exists on its long-term outcomes in this cohort, especially regarding revision rates, mortality, and complications. This registry study aimed to determine these outcomes using data from a large national registry. Methods:This registry study analyzed data from the German Arthroplasty Registry (EPRD), which captures approximately 70% of all hip arthroplasties in Germany. Among 418,409 patients undergoing THA between November 2012 and March 2024, 5,392 were included after 1:1 Mahalanobis distance matching for age, sex, BMI, and comorbidities: 2,696 patients with a history of osteotomy or osteosynthesis compared with 2,696 patients without. Kaplan-Meier survival curves estimated revision and mortality risks over an eight-year follow-up. Results:Over eight years, patients with prior osteotomy or osteosynthesis had significantly higher revision (6.8%, n = 183/2,696 vs 3.9%, n = 105/2,696, p = 0.002) and mortality (25.2%, n = 679/2,696 vs 20.4%, n = 550/2,696, p < 0.001) rates than those without prior hip surgery. Infection (17%, n = 22/131 vs 16%, n = 15/94), periprosthetic fracture (14%, n = 18/131 vs 12%, n = 11/94), and dislocation (14%, n = 18/131 vs 8.5%, n=8/94) were leading causes of revision. For cementless femoral components, prior-surgery patients had an eight-year revision rate of 7.3%, n = 143/1,957 compared with 3.6%, n = 71/1,958 (p = 0.003) and a mortality rate of 17.3%, n = 339/1,957 compared with 10.9%, n = 213/1,958 (p < 0.001). For cemented femoral components, revision rates were 4.9%, n = 36/739, compared with 4.7%, n = 35/738 (p = 0.330), and mortality 46.3%, n = 342/739, compared with 43.0%, n = 317/738 (p < 0.001). At one year, the revision rate in the prior-surgery group was already elevated at 3.7% (95% CI 3.1 to 4.5; n = 100/2,696) compared with 2.6% (95% CI 2.0 to 3.3; n = 70/2,696) in controls, diverging further over time. Conclusion:Patients with prior osteotomy or osteosynthesis undergoing THA face higher long-term revision and mortality risks, particularly with cementless stem fixation. Infection, periprosthetic fracture, and dislocation are key causes of revision.

Background: Periprosthetic joint infection (PJI) following knee arthroplasty can significantly compromise patient mobility and quality of life. The newly proposed TNM classification system, adapted from oncology, categorizes PJI severity but has not yet been correlated with both subjective and objective outcomes post PJI treatment. Objective: This study evaluates the applicability of the TNM classification system for predicting outcomes in knee PJI revision surgeries. Methods: We conducted a retrospective analysis of 108 patients who underwent revision surgeries for knee PJI at our institution from January 2012 to January 2023. We assessed the correlation between the TNM classification and postoperative outcomes using the Knee Society Score (KSS) function and knee score, as well as the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Results: The TNM classification demonstrated that higher ‘T’ stages were significantly associated with worse functional and subjective outcomes. The ‘N’ classification had limited predictive value, likely due to treatment adjustments based on pathogen type. The ‘M’ classification correlated with functional outcomes but not with subjective scores, suggesting that patients with more severe preoperative comorbidities might adjust their expectations. Conclusions: While the TNM classification shows potential, its current form as a prognostic tool in PJI management is limited. Enhancing the ‘T’ component, coupled with the integration of a validated morbidity score such as the CCI could improve its prognostic value. Despite its shortcomings, the TNM system may still provide valuable prognostic insights for both patients and surgeons in tackling complex PJI.

Background: The optimal surgical approach in patients with borderline hip dysplasia (BHD) remains controversial. Both hip arthroscopy and periacetabular osteotomy (PAO) are commonly employed in this patient population. Those who participate in sports want to resume and maintain sports activities after surgery, and the ability to do so plays an important role in the choice of a treatment method. No previous study has assessed return-to-sports rates and activity levels in patients with BHD after PAO. Purpose: To assess return-to-sports rates and postoperative activity levels as measured by the University of California, Los Angeles (UCLA), activity scale as well as patient-reported outcome measures. Also to assess changes in sports activity both qualitatively and quantitatively as well as underlying reasons for these changes. Methods: We conducted a retrospective analysis of prospectively collected data from 55 hips in 52 patients with BHD who underwent PAO between January 2015 and June 2017. Return-to-sports rates, UCLA activity scores, International Hip Outcome Tool-12 scores, Subjective Hip Value scores, Hip disability and Osteoarthritis Outcome Score subscores, sports practiced, frequency and duration of sports activity, and postoperative changes as well as underlying reasons were recorded. Results: Mean follow-up was 62.8 ± 9.0 months. Return-to-sports rate among preoperatively active patients was 92.5%. Most patients resumed sports activity after 6 months (50%) or after 3 to 6 months (37.5%). The UCLA activity score improved significantly (from 5.2 ± 2.4 to 7.0 ± 1.8; P < .001). The iHOT-12, Subjective Hip Value, and HOOS scores also improved significantly (all, P < .001). Changes in sports activity occurred in 34.5% of cases after PAO. Significantly more patients engaged in low-impact sports postoperatively. Participation in high-impact sports did not decrease significantly. Reasons for changes were both hip related and non-hip related. Quantitatively, patients were able to significantly increase both the frequency (P = .007) and duration (P = .007) of sports activity. Conclusion: The return-to-sports rate in patients with BHD after PAO was high at over 92%. Most patients returned to sports after a period of 6 months or 3 to 6 months. Overall, activity levels and hip function improved after PAO. A number of patients adjusted their sports activity after PAO. Although more patients engaged in low-impact sports, participation in high-impact sports was maintained postoperatively. The results of this study may help both patients and orthopaedic surgeons in deciding on the best surgical procedure in the setting of BHD.

Aims: Developmental dysplasia of the hip (DDH) often leads to early osteoarthritis, causing pain and functional limitations that may impair sexual function. This study investigates the impact of periacetabular osteotomy (PAO) on sexual function in DDH patients, assessing changes from preoperative impairments to postoperative improvements. Methods: This retrospective study analyzed data from DDH patients treated with PAO between January 2015 and June 2017 at a single orthopaedic university centre. Data included radiological parameters and patient-reported outcome measures: International Hip Outcome Tool (iHOT-12), Subjective Hip Value, Hip disability and Osteoarthritis Outcome Score (HOOS) and its sub-scores, and Numeric Pain Scale. Sexual function was specifically assessed using iHOT-12 item nine, asking, “How much trouble do you have with sexual activity because of your hip?” Results: The study included 120 hips in 107 patients, predominantly female (85.1%). Radiological improvements post PAO were significant, with increases in the lateral centre-edge angle (LCEA) (16.6° (SD 6.0°) to 29.4° (SD 5.8°); p < 0.001) and reductions in the Tönnis angle (13.3° (SD 6.7°) to 1.2° (SD 7.4°); p < 0.001). Patient-reported outcomes demonstrated significant improvements postoperatively. Specifically, the iHOT-12 sexual function item showed substantial improvement from a mean preoperative score of 54.3 (SD 33.7) to a postoperative score of 75.0 (SD 27.1) (p < 0.001). Females reported significant enhancements in sexual function (p < 0.001), whereas improvements in males did not reach statistical significance (p = 0.181). Cases of under-correction (LCEA < 25°) demonstrated significantly higher impairments in sexual function postoperatively compared with adequately corrected cases, indicating the importance of achieving optimal anatomical correction. Conclusion: PAO significantly enhances sexual function and overall hip-related quality of life in patients with symptomatic DDH. The findings underscore the necessity of precise surgical techniques and highlight that outcomes may vary by sex, suggesting a need for a sex-sensitive approach in both clinical practice and research. Cite this article: Bone Jt Open 2025;6(4):440–445.

Aims Patients with a history of osteotomy or osteosynthesis pose distinct challenges in total hip arthroplasty (THA) due to altered anatomy and biomechanics. Although THA is an established intervention for degenerative hip disease, limited evidence exists on its long-term outcomes in this cohort, especially regarding revision rates, mortality, and complications. This registry study aimed to determine these outcomes using data from a large national registry. Methods This registry study analyzed data from the German Arthroplasty Registry (EPRD), which captures approximately 70% of all hip arthroplasties in Germany. Among 418,409 patients undergoing THA between November 2012 and March 2024, 5,392 were included after 1:1 Mahalanobis distance matching for age, sex, BMI, and comorbidities: 2,696 patients with a history of osteotomy or osteosynthesis compared with 2,696 patients without. Kaplan-Meier survival curves estimated revision and mortality risks over an eight-year follow-up. Results Over eight years, patients with prior osteotomy or osteosynthesis had significantly higher revision (6.8%, n = 183/2,696 vs 3.9%, n = 105/2,696, p = 0.002) and mortality (25.2%, n = 679/2,696 vs 20.4%, n = 550/2,696, p < 0.001) rates than those without prior hip surgery. Infection (17%, n = 22/131 vs 16%, n = 15/94), periprosthetic fracture (14%, n = 18/131 vs 12%, n = 11/94), and dislocation (14%, n = 18/131 vs 8.5%, n=8/94) were leading causes of revision. For cementless femoral components, prior-surgery patients had an eight-year revision rate of 7.3%, n = 143/1,957 compared with 3.6%, n = 71/1,958 (p = 0.003) and a mortality rate of 17.3%, n = 339/1,957 compared with 10.9%, n = 213/1,958 (p < 0.001). For cemented femoral components, revision rates were 4.9%, n = 36/739, compared with 4.7%, n = 35/738 (p = 0.330), and mortality 46.3%, n = 342/739, compared with 43.0%, n = 317/738 (p < 0.001). At one year, the revision rate in the prior-surgery group was already elevated at 3.7% (95% CI 3.1 to 4.5; n = 100/2,696) compared with 2.6% (95% CI 2.0 to 3.3; n = 70/2,696) in controls, diverging further over time. Conclusion Patients with prior osteotomy or osteosynthesis undergoing THA face higher long-term revision and mortality risks, particularly with cementless stem fixation. Infection, periprosthetic fracture, and dislocation are key causes of revision.

Introduction: Due to demographic shifts and an increasing proportion of older adults at higher fracture risk, the overall burden of proximal femur fractures has risen significantly in recent years, placing a burden on patients and healthcare systems. Despite extensive research on hip fracture epidemiology and treatment, the specific influences of femoral and acetabular parameters on fracture localisation remain underexplored. This study evaluates the impact of these parameters on proximal femur fracture localisation. Materials and methods: This retrospective cohort study analysed data from 400 patients with proximal femur fractures, including medial and lateral femoral neck fractures (FNFs), pertrochanteric, and subtrochanteric fractures, treated at a university hospital between 2010 and 2022. Radiographic measurements of femoral head size and other morphological parameters were conducted using pre-operative pelvic radiographs. Statistical analyses included multivariate logistic regression. Results: A larger head-radius vertical (HRV) was associated with an increased risk of lateral FNFs (OR 1.11; p = 0.007). A lower Femoral Head Protrusion Index (FHEI) significantly increased the risk of lateral (OR 0.87; p < 0.001), pertrochanteric (OR 0.88; p < 0.001), and subtrochanteric fractures (OR 0.86; p < 0.001). Femur canal width was associated with a higher risk of pertrochanteric fractures (OR 1.17; p = 0.001), and a smaller lateral centre edge angle (LCEA) correlated with higher risks of lateral (OR 0.92; p = 0.021) and pertrochanteric fractures (OR 0.92; p = 0.018). Additionally, a higher body mass index (BMI) was significantly associated with subtrochanteric fractures (or 1.07; p = 0.020). Conclusions: The study identified key variables associated with proximal femur fracture localisation. Morphological parameters such as HRV, FHEI, canal width, and LCEA, as well as BMI for subtrochanteric fractures, significantly influence fracture localisation, highlighting their importance for personalised risk assessment and preventive strategies.

Plasma cell survival is influenced by various factors, including soluble mediators, intrinsic and extrinsic signals as well as adhesion molecules defining the bone marrow microenvironment. The role of their induction, turnover and competition dynamics among different antigen-specific bone marrow plasma cell subsets is not well understood. This study addresses the co-expression of CD19 and CD56 on both antigen-specific and total human bone marrow plasma cells (BMPC) using multiparametric flow cytometry and data from a previous single-cell RNA sequencing (scRNA-seq) study. While the RNA-seq data reflects characteristics of total BMPC, flow cytometry data enables detailed comparison of antigen-specific subsets, such as tetanus toxoid (TT)- and receptor binding domain (RBD, a region of the SARS-CoV-2 spike protein)-specific BMPC. CD56 expression is enriched among CD19- BMPC, particularly on those expressing IgG. RBD-specific BMPC typically lack CD56 expression, while TT-specific BMPC exhibit a substantially enriched CD56+CD19- BMPC population. Phenotypic and transcriptional characteristics (CD19 and NCAM1 [CD56] co-expression) together with distinct transcriptional profiles (including cell-cell adhesion, endopeptidase activity) and IgG/IgA expression identified remarkable differences between RBD-specific and TT-specific BMPC. These findings suggest that CD56 likely facilitates tissue retention of rather long-lived BMPC lacking CD19 expression. Given the emerging potential of selective BMPC subsets, this study may provide a rational for optimized vaccination protocols, as well as for selective plasma-cell targeting in autoimmunity. In this context, CD56+CD19- BMPC emerge as potential candidates for a long-lived and stable compartment.

Across tissues, tissue-resident memory T cells have been defined as cells that express CD69 on their cell surface but not sphingosine-1-phosphate receptor 1 (S1PR1), the receptor for the tissue-egress signal sphingosine-1-phosphate (S1P). It is less clear whether CD69-negative memory T cells are also tissue-resident. Here, we compare transcriptomes and T cell receptor repertoires of individual CD4 and CD8 memory T cells from paired blood and bone marrow samples from three human donors. CD69- memory T cells of blood and bone marrow share transcriptionally defined clusters, characterized by signature genes and reflecting their imprinting during original activation. However, cells of related clusters from blood and bone marrow have different TCR repertoires, evidence that they represent distinct compartments of memory and indicating that the CD69- memory T cells are residents of the bone marrow. Interestingly, the surface CD69- memory T cells of bone marrow do transcribe the CD69 gene and express S1PR1, suggesting that they are blindfolded to the perception of the egress signal sphingosine-1-phosphate by dimerization and internalization of CD69 and S1PR1, maintaining them in the bone marrow.

Aims:The classic, widely accepted approach for one-stage hip revision arthroplasty in patients with periprosthetic joint infection (PJI) is the cemented exchange. This approach provides stable implant anchoring despite bone defects after removal of infected components, and facilitates local antibiotic delivery. This study aims to investigate the efficacy of cementless one-stage hip revision arthroplasty using a gentamicin-eluting bone graft substitute (GBGS) to address both bone defect filling and antibiotic elution. Methods:We conducted a prospective analysis of 20 patients with confirmed PJI undergoing cementless one-stage hip revision arthroplasty using GBGS. The GBGS was used to fill femoral and acetabular defects during implantation. Clinical outcomes, radiographs, adverse events, and patient-reported outcome measures (PROMs) including Harris Hip Score (HHS) and EuroQol five-dimension five-level questionnaire (EQ-5D-5L) were assessed. Patients received 12 weeks of systemic antibiotics and were followed up for at least 24 months. Results:The mean age of the cohort was 66.3 years (SD 8.4; 46 to 80), with ten female and ten male patients. On average, 13.2 ml (SD 3.9; 5 to 17) of GBGS was applied to bone defects. No reinfections occurred during the follow-up period of 3.3 years (SD 0.92; 2.1 to 4.8). We observed 15 serious adverse events (SAEs), none of which were associated with the product. All cases showed good bony consolidation and prosthesis integration at 12 months. Significant improvements were seen in HHS (preoperative mean: 47.7; final visit mean: 80.1; p < 0.001) and EQ-5D-5L score (preoperative mean: 0.43; 12-month mean: 0.88; p < 0.001). Conclusion:This prospective pilot study is the first to demonstrate the safety and feasibility of single-stage cementless hip exchange arthroplasty using GBGS in managing PJI and associated bone defects. The technique resulted in significant improvements in functional outcomes and quality of life, with a good safety profile. Further studies with larger cohorts are warranted to validate these findings.

We investigated whether neurologic and psychiatric disorders (ICD-10 F00–F99, G00–G99) increase postoperative complications and mortality after hip arthroplasty and identified subgroups with distinct complication patterns, including dislocations, loosening, fractures, and elevated mortality. We analyzed 190,340 primary cementless hip arthroplasties from the German Arthroplasty Registry (2012–2024). Patients with relevant diagnoses were compared to matched controls (1:1 Mahalanobis distance) across subgroups F00–F99 and G00–G99, adjusting for age, sex, BMI, Elixhauser Index, and arthroplasty type. Primary endpoints were implant survival (time to revision) and all-cause mortality over up to eight years. Revision causes including periprosthetic fracture, infection, dislocation, loosening, and others were systematically recorded. Most subgroups showed significantly higher revision rates (p < 0.0001 for F00–F09, F10–F19, F30–F39, G20–G26, G40–G47, G60–G64). Mortality was also significantly higher (p < 0.0001 for F00–F09, F10–F19, F30–F39). Schizophrenia (F20–F29) increased revision (p < 0.0001) and mortality (p < 0.0001). Organic mental disorders (F00–F09) showed markedly elevated revision and mortality rates, with more frequent dislocations and fractures (p < 0.0001). Extrapyramidal disorders (G20–G26) mainly increased dislocation risk (p = 0.00032), while degenerative diseases (G30–G32) raised mortality (p < 0.0001). Episodic/paroxysmal disorders (G40–G47) increased loosening (p = 0.0041) and revision (p < 0.0001). Polyneuropathies (G60–G64) were linked to joint instability and dislocations (p = 0.0008). Neurologic and psychiatric disorders significantly elevate revision and mortality risks following hip arthroplasty. Subgroup-specific vulnerabilities, dislocations/fractures (F00–F09), high complication and mortality (F10–F19), and joint instability (G60–G64), highlight the need for individualized perioperative strategies and close postoperative monitoring to improve outcomes.

Background:Proximal femur fractures are prevalent among the elderly, leading to high mortality, reduced quality of life, and significant healthcare burdens. The incidence is rising with demographic ageing, with osteoporotic fractures projected to reach 6 million annually by 2050, costing $25.4 billion. A 351 % increase in proximal femur fractures among individuals over 85 years is expected. Accurate fracture localization through imaging, combined with understanding femoral head size and patient-specific factors, improves preoperative planning and outcomes. This study explores the relationship between femoral head size and fracture localization. Methods:A retrospective cohort study analyzed data from 400 patients with proximal femur fractures treated between 2010 and 2022. Fractures were classified as medial, lateral, pertrochanteric, or subtrochanteric. Radiographs measured femoral head morphology, and statistical analyses, including chi-square tests, t-tests, ANOVA, and logistic regression, identified predictors of fracture localization. Results:Femoral head area (FHA) varied significantly across fracture types, with lateral fractures having the largest mean FHA (2355.95 mm2/cm2, p = 0.047). Osteoarthritis prevalence differed (p = 0.028), being highest in subtrochanteric fractures (17 %, Kellgren & Lawrence grade 3-4). Lateral fractures had a younger mean age of 71.05 years (p < 0.001), while pertrochanteric fractures averaged 79.52 years (p < 0.001). Vertical (p < 0.001) and horizontal (p = 0.028) femoral head diameters also differed significantly. Conclusion:Larger femoral heads are associated with lateral fractures, whereas pertrochanteric fractures occur in older patients. Subtrochanteric fractures correlate with smaller femoral heads and advanced osteoarthritis.

Background: To evaluate the function of the abductor mechanism after a gluteus maximus flap transfer due to a degeneration of the muscles after hip arthroplasty, we analyzed the post-operative functional outcome as well as radiographic effects in muscle tissue. Methods: This present study included six consecutive patients operatively treated with a gluteus maximus flap due to chronic gluteal deficiency after total hip arthroplasty. All patients presented a preoperative severe limp, hip abductor deficiency and a history of conservative treatment without the relief of symptoms. MRI scans were performed pre- and postoperatively to evaluate the muscle volume and grade of degeneration of the abductor mechanism. For clinical evaluation, the Harris hip score (HHS) was applied pre- and postoperatively. Moreover, the intensity of pain, the Trendelenburg sign, the internal rotation lag sign and the abductor muscle force were measured before and after surgery. Results: Overall, the evaluation of the Magnetic Resonance Imaging (MRI) showed no significant changes in total muscle volume during the follow-up period. Separate measurements presented a significant growth of muscle volume for the gluteus minimus and tensor fascia lata compared to preoperative imaging during the follow-up period. The amount of fat volume decreased for all the measured muscles with statistical significance for the gluteus minimus, the gluteus medius and the tensor fascia lata. No further muscle degeneration and no flap necrosis were measured. The postoperative HHS results were not statistically significant compared to the preoperative results. Conclusions: Besides fair clinical results, the radiological measurements indicate that the flap transfer enables functional muscular tissue recovery and prevents further degeneration. Given these conditions, the gluteus maximus muscle flap transfer represents a viable treatment option for patients with chronic gluteal deficiency in selected patients. Keywords: Abductor Mechanism Deficiency; Gluteus Maximus Flap Transfer

BACKGROUND:Psychiatric and neurologic comorbidities may worsen outcomes after total knee arthroplasty (TKA) or unicompartmental knee arthroplasty (UKA). We compared risks across eight International Classification of Diseases, Tenth Revision, German Modification clusters-psychiatric F00 to F39 and neurologic G20 to G64-and by implant constraint (unconstrained, constrained, and unicompartmental). METHODS:We analyzed 549,234 primary knee arthroplasties (2012 to 2024) from a national arthroplasty registry. Patients who had diagnoses were matched one-to-one to controls without F00 to F99 or G00 to G99 codes, adjusting for age, sex, body mass index (BMI), Elixhauser index, fixation, and implant type. Kaplan-Meier with 95% confidence intervals (CIs) estimated 8-year incidence; multivariable Cox models estimated hazard ratios (HRs) by diagnoses and implant. RESULTS:Complication patterns varied by cluster. The revision risk was highest in F20 to F29 (schizophrenia spectrum; HR 1.92, P = 0.001) and G20 to G26 (extrapyramidal/parkinsonian; HR 1.66, P < 0.001). Infection peaked in F00 to F09 (organic/cognitive; HR 2.34, P < 0.001) and G60 to G64 (polyneuropathy; HR 1.52, P < 0.001). Loosening increased from F30 to F39 (affective; HR 1.50) and from G20 to G26 (extrapyramidal/Parkinsonian; HR 1.92, P < 0.001). All-cause mortality was highest in F20 to F29 (schizophrenia spectrum; HR 3.01, P < 0.001), F00 to F09 (organic/cognitive; HR 2.28, P < 0.001), and G30 to G32 (degenerative central nervous system; HR 2.65, P < 0.001). Periprosthetic fracture after UKA tripled in F30 to F39 (affective; HR 3.99, P < 0.001), G20 to G26 (extrapyramidal/parkinsonian; HR 3.70, P < 0.001), and G40 to G47 (episodic/paroxysmal; HR 3.78, P < 0.001). Constrained TKA amplified infection and mortality across clusters. Unicompartmental knee arthroplasty lowered mortality in some cohorts (e.g., F30 to F39 [affective]; HR 0.52, P < 0.001), but carried the highest loosening and fracture risk. CONCLUSIONS:Psychiatric and neurologic comorbidities are heterogeneous, independent predictors of failure after TKA/UKA; implant design modifies risk. An International Classification of Diseases, Tenth Revision, German Modification-based, code plus-name approach may guide implant selection, discourage the use of constrained or unicompartmental devices in patients who are vulnerable, and inform perioperative care.

BACKGROUND:Proximal humerus fractures (PHFs) are the third most common fractures in elderly patients. Over 70% of PHFs in patients aged over 60 are displaced fractures, often necessitating surgical treatment. However, osteosynthesis is associated with a high rate of complications, highlighting the urgent need for additional therapeutic approaches to enhance bone healing and prevent osteonecrosis. This study evaluates the safety, feasibility and potential efficacy of local prostacyclin (iloprost) to improve bone healing in patients with PHFs. METHODS:Thirty eligible patients will be randomized into one of three groups at a 1:1:1 ratio. All patients will receive angular stable locking plate fixation. Two treatment groups will receive an additional single dose of local iloprost through a 24-hour infusion postoperatively (group 1: low dose; group 2: high dose), while the control group will only receive the osteosynthesis. Patients will be monitored for 52 weeks. The primary endpoint is safety, with secondary endpoints including the preservation of the screw tip apex distance as an indicator of fracture healing, head shaft angle, necrosis rate, and patient-related outcome measures. DISCUSSION:The Ilobone study aims to provide data on the potential for biological augmentation of osteosynthesis procedures in PHFs, prone to healing challenges and complications. TRIAL REGISTRATION:The trial is registered with ClinicalTrial.gov (NCT04543682), registered 02 Sep. 2020, https://clinicaltrials.gov/show/NCT04543682 and the German Clinical Trials Registry (DRKS00027081), registered 10 Nov. 2021 https://drks.de/search/de/trial/DRKS00027081 .