Klemens Vertesich

Background/Objectives: Accurately diagnosing a periprosthetic joint infection (PJI) represents a challenging and complex task. Especially in the case of low-grade infections, important diagnostic modalities may be inconclusive and synovial markers such as white blood cell count (WBC) and polymorphonuclear percentage (PMN) gain relevance. We therefore aim to assess WBC and PMN in different clinical and microbiological settings. Methods: We performed a retrospective analysis of 115 patients with a diagnosed PJI. WBC and PMN were compared between patients with low- and high-virulent infections, negative and positive histology, symptom duration ≤ 4 weeks and >4 weeks, and positive and negative pathogen detection. Results: Synovial WBC was significantly higher in patients with successful pathogen detection (42.44 [87.0] G/L vs. 16.35 [32.0] G/L; p < 0.01), as was PMN (86.0 [60.0]% vs. 91.0 [89.0]%; p < 0.01). PJIs with high-virulent pathogens showed higher WBC compared to low-virulent pathogens (58.27 [102.0] G/L vs. 27.27 [46.0] G/L; p < 0.01). Patients with onset of symptoms ≤ 4 weeks demonstrated higher WBC (58.27 [112.0] G/L vs. 16.42 [46.0] G/L]; p < 0.01) as well as higher PMN (91.5 [9.0]% vs. 88.0 [20.0]%); p = 0.042). Cases with negative histology showed significantly lower WBC (16.73 [44.0] G/L vs. 42.86 [87.0] G/L; p < 0.01) and lower PMN (86.0 [67.0]% vs. 91.0 [9.0]%; p = 0.036). Conclusions: WBC and PMN show high variability and appear to be influenced by virulence, histology, onset of symptoms, and pathogen detection.

Background: Artificial intelligence (AI), particularly AI-based large language models (LLM) like ChatGPT, is increasingly shaping how information is accessed, offering patients a new source for understanding complex medical conditions. Given the physical, emotional, and logistical challenges that parents are faced when their baby is diagnosed with developmental dysplasia of the hip (DDH), the demand for clear and accessible educational resources is high. This study aimed to evaluate the quality and reliability of ChatGPT's responses to frequently asked questions about DDH. Methods: This study assessed the quality of responses generated by the AI chatbot ChatGPT 4o to eight frequently asked questions about DDH, derived from real consultations in a pediatric orthopedic clinic Responses were generated during one interaction per question using a ChatGPT account not previously exposed to medical information. Responses were evaluated by two individual readers using a standardized rating system, comparing them to current literature, patient education resources, and consensus guidelines. Each response was categorized by its level of informational accuracy and completeness, and descriptive statistics were calculated to quantify performance. Results: ChatGPT 4o was able to generate structured responses to all eight parental questions. The responses were rated in 12.5% excellent, 25.0% satisfactory with minimal clarification, 50.0% satisfactory with moderate clarification, and 12.5% unsatisfactory due to missing or inaccurate information. Conclusion: ChatGPT provided satisfactory answers to questions about DDH and may serve as a useful supplementary information resource for parents. However, due to limitations in presenting detailed diagnostic and treatment pathways, it should be viewed as an adjunct to, not a replacement for, specialist medical consultation.

Background: The reproducible measurement of tibial torsion (TT) is essential for the diagnosis and evaluation of rotational deformities of the tibia, particularly in the planning of tibial derotational osteotomy. While various CT-based methods for determining the distal tibial axis have been described for adult patients, rotational Magnetic Resonance Imaging (MRI) represents a radiation-free alternative, especially for assessing lower limb rotation in pediatric patients. The aim of this study was to analyze the reliability of TT measurements as well as to investigate potential differences in the application of rotational MRI within a pediatric orthopedic cohort. Methods: In this retrospective study, 78 lower legs from 39 patients aged 4 to 18 years who underwent rotational MRI were included. Measurements for TT were performed using the Jend method, the Waidelich method, and the bimalleolar method. Reliability assessments were conducted by three different examiners, and the results were determined using the intraclass correlation coefficient (ICC). Results: All three methods demonstrated excellent interobserver reliability. The highest intraobserver reliability was achieved using the bimalleolar method (ICC: 0.947). When comparing the assessment of TT, the Jend method showed the highest mean values (34°, standard deviation (SD) 11.0°) followed by the Waidelich method (29°, SD 10.2°) and the bimalleolar method (26°, SD 9.9°). Measurement methods showed a mean difference of up to 8° (p < 0.001). Conclusions: Rotational MRI is a feasible radiation-free option to assess tibial torsion in pediatric and adolescent patients. All tested methods show excellent inter- and intraobserver reliability. Notably, significant differences were found between the measurement methods, with the bimalleolar method showing lower mean values. This has to be taken into account for preoperative planning of rotational and derotational tibial and supramalleolar osteotomies.

Background: Balance and gait are critical for functional recovery and fall prevention following total hip (THA) and knee arthroplasty (TKA). Despite improvements in pain and joint function, residual impairments often persist. The Timed Up and Go (TUG) test and Tinetti Performance-Oriented Mobility Assessment (POMA) objectively measure postoperative mobility and balance, while patient-reported outcome measures (PROMs) assess perceived function and well-being. This study longitudinally evaluates functional measurement and PROMs to explore their interrelationships and compare recovery trajectories in THA and TKA cohorts. Methods: In this prospective study, 22 THA and 21 TKA patients were assessed preoperatively and at 4–6 days, 6 weeks, 3 months, and 12 months postoperatively using TUG, Tinetti, Hip Disability and Osteoarthritis Outcome Score (HOOS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and clinical scores (Harris Hip Score (HHS) for THA, Knee Society Score (KSS) for TKA). Pearson correlation assessed relationships between measures. Results: Both cohorts demonstrated significant immediate postoperative declines in balance and mobility, recovering to baseline by 6 weeks and surpassing it by 3 and 12 months (p < 0.001). PROMs showed earlier and sustained improvements. Objective balance and mobility measures showed minimal correlation with PROMs but were highly interrelated from 6 weeks onward. Conclusions: THA and TKA patients experience early postoperative balance impairments, suggesting heightened fall risk, with functional recovery lagging behind perceived well-being, highlighting the need for cautious rehabilitation strategies.

Background: Although cemented total knee arthroplasty (TKA) is considered the standard fixation technique, the emerging trend toward cementless fixation has created the need for a detailed comparison. In a previous study, we reported the 5-year results comparing cementless and hybrid cemented TKAs using the same implant design. The purpose of this study was to assess the long-term follow-up at a minimum of 10 years. Methods: A retrospective analysis was performed on 120 TKAs (60 cementless, 60 hybrid cemented) conducted between 2003 and 2007 using the e.motion posterior cruciate-retaining knee prosthesis with a floating-platform mobile polyethylene bearing (Aesculap, Tuttlingen, Germany). Demographic and clinical data were collected; radiographic follow-up was performed with attention to signs of loosening, while complications and revision surgery were assessed using competing risk analysis. Operative time was recorded as an indicator of surgical efficiency. Results: At 10 years, 59 TKAs (54 patients) were available for long-term follow-up. Both fixation groups demonstrated significant improvement in Knee Society Scores (KSSs) compared to preoperative values (p < 0.001). However, there was no significant difference in KSSs between the two groups at 10 years follow-up (p = 0.480). The 10-year cumulative incidence of revision was 8.4% in both groups (p = 0.721), and that of aseptic loosening was identical at 3.4% (p = 0.967). Although radiolucent lines were noted in three tibial components of the cementless group, the difference was not statistically significant (p = 0.075). Notably, the cementless group demonstrated a significantly shorter operative time with a mean difference of 10 min (p = 0.017). Conclusions: At a minimum follow-up of 10 years, there were no significant differences between the hybrid cemented and cementless groups in revision rates, cumulative incidences, clinical scores, or radiological signs of loosening, confirming the long-term effectiveness of both fixation methods in clinical practice.

Although cemented total knee arthroplasty (TKA) is considered the standard fixation technique, the emerging trend toward cementless fixation has created the need for a detailed comparison. In a previous study, we reported the 5-year results comparing cementless and hybrid cemented TKAs using the same implant design. The purpose of this study was to assess the long-term follow-up at a minimum of 10 years. Methods: A retrospective analysis was performed on 120 TKAs (60 cementless, 60 hybrid cemented) conducted between 2003 and 2007. Demographic and clinical data were collected, ra-diographic follow-up was performed with attention to signs of loosening, while compli-cations and revision surgery were assessed using competing risk analysis. Operative time was recorded as an indicator of surgical efficiency. Results: At 10 years, 59 TKAs (54 patients) were available for long‐term follow‐up. Both fixation groups demonstrated significant improvement in Knee Society Scores (KSS) compared to preoperative values (p < 0.001). However, there was no significant difference in KSS between the two groups at 10 years follow-up (p = 0.480). The 10-year cumulative incidence of revision was 8.4% in both groups (p = 0.721), and that of aseptic loosening was identical at 3.4% (p = 0.967). Although radiolucent lines were noted in three tibial components of the cementless group, the difference was not statistically significant (p = 0.075). Notably, the cementless group demonstrated a significantly shorter operative time with a mean difference of 10 minutes (p = 0.017). Conclusions: At a minimum follow-up of 10 years, there were no significant differences between the hybrid cemented and cementless groups in revision rates, cu-mulative incidences, clinical scores, or radiological signs of loosening, confirming the long-term effectiveness of both fixation methods in clinical practice.

Background/Objectives: We evaluated the outcomes of patients undergoing en bloc total vertebrectomy at our institution within the last three decades. The aim of our study was to analyse the oncological and neurological outcomes and the changes over time. Methods: We included 22 consecutive patients treated with a total vertebrectomy at our institution between January 1990 and December 2022. The standard follow-up protocol for sarcoma patients was performed. Early complications were defined as complications within the first three months postoperatively. Local recurrence was defined as the reoccurrence of a tumour at least four months after surgery. Adequate statistical methods were applied to evaluate the survival rates and the influence of potential risk factors. A p-value of <0.05 was considered statistically significant. Results: From 1990 to 2010, five total vertebrectomies were performed each decade, whereas twelve patients underwent the procedure in the period from 2010 to 2022. The mean follow-up period was 101.25 months (±112; 2–339). The one-, five- and ten-year overall survival rates were 91% (CI = (0.79; 1.00)), 59% (CI = (0.37; 0.81)) and 51% (CI = (0.27; 0.75)), respectively. For soft tissue tumours, the average overall survival was 6.2 years, whereas, for bone sarcomas, it was 13.6 years. None of the patients with wide surgical margins developed local recurrence. Complications necessitating revision procedures occurred in 54% of all cases. Conclusions: A total vertebrectomy is a highly demanding procedure, requiring accurate patient selection, meticulous preoperative planning and a highly collaborative interdisciplinary team. Adequate surgical treatment seems to be indispensable when aiming for curative treatment. Owing to the rarity of the indications, this procedure should be restricted to large tumour centres.

Several authors observed a loss of correction after performing Chiari pelvic osteotomy (CPO) in young patients. Hence, the aim of this study was to answer two questions: (1) Does the Chiari pelvic osteotomy affect the development of the acetabulum in skeletally immature patients in the long term? (2) Is there any evidence of the previously described “Anti-Chiari” effect after a mean follow-up of 36 years? Data from 21 patients (27 hips) undergoing CPO before the age of 16 years were clinically assessed, and the evolution of radiological parameters over time was analyzed. The mean age at CPO was 11.2 years (±3; 4.4–15.7). The 20- and 30-year survival rates of the CPO were 100% and 92.6%, respectively. Mean postoperative medialization was 54% (±18; 23–99). The average osteotomy angle was 11° (±7; 2–28). No significant changes were found for the center-edge angle (CEA) and acetabular index (AI) over time; the angle of Idelberger and Frank (ACM) almost reached normal values at follow-up (FU); for the acetabular-head index (AHI), a slight shift toward the initial situation could be detected. The morphology of the acetabulum remained unchanged over time. The “Anti-Chiari effect” seems to be primarily caused by insufficient coverage of the femoral head rather than damage to the apophysis due to surgery.

Introduction: Multiple revision hip arthroplasties and critical trauma might cause severe bone loss that requires proximal femoral replacement (PFR). The aim of this retrospective study was to analyse complication- and revision-free survivals of patients who received modular megaprostheses in an attempt to reconstruct massive non-neoplastic bone defects of the proximal femur.Questions/purposes(1) What were general complication rates and revision-free survivals following PFR? (2) What is the incidence of complication specific survivals? (3) What were risk factors leading to a diminished PFR survival?Materials and methods: Twenty-eight patients with sufficient follow-up after receiving a modular proximal femoral megaprosthesis were identified. The indications for PFR included prosthetic joint infection (PJI), periprosthetic fracture, aseptic loosening, non-union and critical femoral fracture. Complications were grouped according to the ISOLS-classification of segmental endoprosthetic failure by Henderson et al.Results: Overall, the complication-free survival was 64.3% at one year, 43.2% at five years and 38.4% at ten years, with 16 patients (57%) suffering at least one complication. Complications were dislocation in eight patients (29%), PJI in 6 patients (21%), periprosthetic fracture in five patients (18%), and aseptic loosening in six patients (21%). Prosthesis stem cementation showed a lower risk for revision in a cox proportional hazard model (95% CI 0.04–0.93, HR 0.2, p = 0.04).Conclusion: PFR with modular megaprostheses represents a viable last resort treatment with high complication rates for patients with severe proximal femoral bone loss due to failed arthroplasty or critical fractures. In revision arthroplasty settings, PFR cementation should be advocated in cases of impaired bone quality.

Administration of bisphosphonates following total joint arthroplasty might be beneficial to reduce aseptic loosening. However, their effects on peri‐implant bone formation and bone–implant interface strength have not been investigated yet. We used a physiologically loaded mouse implant model to investigate the short‐term effects of postoperative systemic alendronate on osseointegration. A titanium implant with a rough surface was inserted in the proximal tibiae of 17‐week‐old female C57BL/6 mice (n = 44). Postimplantation mice were given alendronate (73 μg/kg/days, n = 22) or vehicle (n = 22) 5 days/week. At 7‐ and 14‐day postimplantation, histology and histomorphometry were conducted. At 28 days, microcomputed tomography and biomechanical testing were performed (n = 10/group). Postoperative alendronate treatment enhanced osseointegration, increasing maximum pullout load by 45% (p < .001) from 19.1 ± 4.5 N in the control mice to 27.6 ± 4.9 N in the treated mice, at day 28 postimplantation. Alendronate treatment increased the bone volume fraction by 139% (p < .001) in the region distal to the implant and 60% (p < .05) in the peri‐implant region. At 14‐day postimplantation, alendronate treatment decreased the number of osteoclasts per bone perimeter (p < .05) and increased bone volume fraction (p < .01) when compared with the control group. Postimplantation, short‐term alendronate treatment enhanced osseointegration as demonstrated by increased bone mass, trabecular bone thickness, and maximum pullout load. Alendronate decreased peri‐implant osteoclasts while preserving peri‐implant osteoblasts and endothelial cells, in turn, increasing bone volume fraction. This data supports the postoperative clinical use of bisphosphonates, especially in patients with high risks of aseptic loosening.