A novel in situ customizable osteosynthesis technique, Bonevolent™ AdhFix, demonstrates promising biomechanical properties under the expertise of a single trained operator. This study assesses inter- and intra-surgeon biomechanical variability and usability of the AdhFix osteosynthesis platform. Six surgeons conducted ten osteosyntheses on a synthetic bone fracture model after reviewing an instruction manual and completing one supervised osteosynthesis. Samples underwent 4-point bending tests at a quasi-static loading rate, and the maximum bending moment (BM), bending stiffness (BS), and AdhFix cross-sectional area (CSA: mm²) were evaluated. All constructs exhibited a consistent appearance and were suitable for biomechanical testing. The mean BM was 2.64 ± 0.57 Nm, and the mean BS was 4.35 ± 0.44 Nm/mm. Statistically significant differences were observed among the six surgeons in BM (p < 0.001) and BS (p = 0.004). Throughout ten trials, only one surgeon demonstrated a significant improvement in BM (p < 0.025), and another showed a significant improvement in BS (p < 0.01). A larger CSA corresponded to a statistically significantly higher value for BM (p < 0.001) but not for BS (p = 0.594). In conclusion, this study found consistent biomechanical stability both across and within the surgeons included, suggesting that the AdhFix osteosynthesis platform can be learned and applied with minimal training and, therefore, might be a clinically viable fracture fixation technique. The variability in BM and BS observed is not expected to have a clinical impact, but future clinical studies are warranted.

Background: Plasma IL-6 and YKL-40 are prognostic biomarkers for OS in patients with different types of solid tumors, but they have not been studied in patients before surgery of metastatic bone disease (MBD) of the extremities. The aim was to evaluate the prognostic value of plasma IL-6 and YKL-40 in patients undergoing surgery for MBD of the extremities. Patients and Methods: A prospective study included all patients undergoing surgery for MBD in the extremities at a tertiary referral center during the period 2014–2018. Preoperative blood samples from index surgery were included. IL-6 and YKL-40 concentrations in plasma were determined by commercial ELISA. A total of 232 patients (median age 66 years, IQR 58–74; female 51%) were included. Results: Cox regression analysis was performed to identify independent prognostic factors for OS. IL-6 correlated with YKL-40 (rho = 0.46, p < 0.01). In univariate analysis (log₂ continuous variable) IL-6 (HR = 1.26, 95% CI 1.16–1.37), CRP (HR = 1.20, 95% CI 1.12–1.29) and YKL-40 (HR = 1.25, 95% CI 1.15–1.37) were associated with short OS. In multivariable analysis, adjusted for known risk factors for survival, only log₂(IL-6) was independently associated with OS (HR = 1.24, 95% CI 1.08–1.43), whereas CRP and YKL-40 were not. Conclusion: High preoperative plasma IL-6 is an independent biomarker of short OS in patients undergoing surgery for MBD.

A novel composite patch osteosynthesis technique (CPT) has demonstrated promising ex vivo biomechanical performance in small tubular bones. To bridge the gap toward clinical evaluations, this study compared the stability of the CPT to a stainless-steel locking plate (LP) in an experimental in vivo ovine bilateral proximal phalanx fracture model. Eight sheep underwent a midline osteotomy with a 4.5 mm circular unicortical defect in the lateral proximal phalanx of both front limbs, treated with the CPT (n = 8) or the LP (n = 8). A half-limb walking cast, or a custom off-loading hoof shoe, was used for postoperative protection. Implant stability was assessed by post-surgery X-ray evaluations and post-euthanasia (16 weeks) dual-energy X-ray absorptiometry (DXA). At week one, all CPT implants demonstrated mechanical failure, while all LPs remained overall intact. Mean BMD was 0.45 g/cm² for CPT and 0.60 g/cm² for LP in the fracture area (p = 0.078), and 0.37 g/cm² vs. 0.41 g/cm² in the distal epiphysis (p = 0.016), respectively. In conclusion, the CPT demonstrated indications of inferior stability compared to the LP in this fracture model, which may limit its clinical applicability in weight-bearing or high-load scenarios and in non-compliant patients.

Purpose: Polymethyl-methacrylate cement (PMMA) is often used as bone defect reconstruction material after surgical removal of giant cell tumors. The purpose of this study was to investigate if the application of PMMA improves the local recurrence rates for giant cell tumors (GCT) of appendicular bone treated with intralesional curettage. Methods: A retrospective analysis of all appendicular GTCs treated at two major Danish sarcoma centres between the 1^st of January 1998 and December 31^st 2013; minimum follow-up of 3.0 years (median: 8.9; 1.3–18.7 years). Kaplan-Meier survival model, log-rank and multivariate Cox regression were used to calculate and compare local recurrence rates. p-values <0.05 were considered statistically significant. Results: 102 patients (M59/F43), median age 31Y (11–84) were included in this study. The overall 3-years local recurrence-rate was 19.9% (95%CI: 11.9–27.9%); 91% had occurred within 3 years. In patients treated with intralesional curettage ( n = 64), the 3-years recurrence-rate was 30.6% (95%CI: 18.8–42.4%), compared to 2.6% (95%CI: 0.0–7.8%) in patients treated with wide resection or amputation ( n = 38), p < .001. The 3-years recurrence-rate for patients treated with intralesional curettage and reconstruction using PMMA was 29.0% (95%CI: 12.6–45.4%) and without PMMA: 31.8% (95%CI: 15.2–48.4%), p = .83. Conclusion: We found that the use of PMMA for bone defect reconstruction after intralesional curettage of GTCs in the appendicular skeleton did not ensure a reduced risk of local recurrence.

Purpose: Manual anthropometric evaluations of pediatric lower extremities are essential in orthopedic pediatric practice due to their noninvasive and time-feasible nature. Therefore, this study aims to assess the test–retest reliability of clinical measurements obtained on children to examine measurement stability over time. Methods: In a test–retest design, data were collected from 50 Danish school children with 5–to 6 weeks between sessions. Measurements encompassed the joint range of motion (ROM), rotational profile, and angular alignment of lower extremities for a representative sample of school children. Reliability was assessed using intraclass correlations (ICC), and agreement was assessed using limits of agreement (LoA) and precision. Results: Reliability analysis revealed excellent results for foot length (ICC > 0.9), good results for foot width (ICC < 0.9), and poor to moderate results for all other measurements (ICC < 0.5, ICC < 0.75). Agreement results for hallux valgus were acceptable (within established reference) and the remaining variables were not acceptable (outside established reference). Conclusions: The majority of the manual assessment procedures were found to have poor reliability. This study highlights the need for reliable and time-efficient tools to assist clinicians in assessing manual clinical measurements and future research should explore this. Level of evidence: Level III.

Background: Calcaneus fractures are known to be difficult and challenging traumatic conditions, the surgical treatment aims to restore normal anatomy and joint line congruency, however, this is with a high risk of infections and complicated wound healing. This study aims to evaluate the outcome of 202 patients with severe calcaneus fractures due to trauma, from 2012 – 2016 in a single centre study (Rigshospitalet, Denmark). Material and methods: A retrospective single-centre cohort study including 202 patients with 221 calcaneus fractures (19 patients had bilateral fractures) due to trauma, between 2012 - 2016. Surgical treatment for intraarticular fractures has at the beginning of the study been performed with a J/L shaped approach but during the study period, a change to a more minimal technique with the sinus tarsi approach was made. Patients were identified from surgery board and medical coding and in a retrospective study design evaluation at 8 weeks, 26 weeks and 52 weeks postoperatively were obtained from medical records.Two experienced orthopaedic surgeons measured the Böhler and Gissane angles on conventional X-rays on the lateral view. Results: In total, 221 calcaneal fractures were recorded during this study, 19 patients had bilateral calcaneal fractures and 217 were treated surgically. Intraarticular fractures (n=181) constitute 83% and extraarticular fractures (n=36) 17% of total. Twelve patients had an open injury (6%), 58 (27%) patients had other injuries related to the trauma (upper extremity n=12, lower extremity n=22, internal organs n=9, spine n=16, head n=2 and pelvic n=2), five of them with multi-trauma. Mean Böhler angle preoperative was 9.4 degrees (range: -20 ; 40) and mean postoperative angle was 27.7 degrees (range: 10 ; 45) with a significant improvement (p<0.001). Mean Gissane angle preoperative was 107.4 degrees (range: 52 ; 147) and mean postoperative angle was 124.1 (range: 102 ; 147) with a significant improvement (p<0.001). Conclusion: We can conclude that a significant improvement of Böhler and Gissane angle are observed and soft-tissue complication still constitutes a major complication postoperatively.