Pierre-Alexandre Poletti

Hallux valgus is increasingly characterized using weight-bearing computed tomography (WBCT), which provides three-dimensional information on first-ray alignment and articular relationships under load. However, structural abnormalities identified on static WBCT should not be equated with direct measurements of biomechanics or function. This narrative review examines the evidentiary transition from structural WBCT findings to biomechanical interpretation in hallux valgus. Normal first-ray mechanics provide the reference framework for evaluating altered tarsometatarsal alignment, first-metatarsal rotation, metatarsosesamoid relationships, and medial-column coupling. Throughout the review, three levels of evidence are distinguished: structural relationships directly demonstrated by WBCT, biomechanical interpretations supported by anatomical or experimental evidence, and dynamic functional or prognostic consequences that require independent validation. Within this framework, coexisting three-dimensional abnormalities may be interpreted as mechanically interrelated without implying a universal causal sequence. Postoperative WBCT can characterize residual or corrected structural relationships, but normalization of imaging parameters does not by itself establish restoration of dynamic function or superior clinical outcome. Computational modeling may extend patient-specific geometry toward mechanical estimation, although its validity depends on model assumptions and independent validation. The principal contribution of WBCT is therefore to provide detailed structural information under load that can inform biomechanical hypotheses, while the functional and prognostic significance of these findings remains to be established through dynamic and longitudinal studies.

Background/Objectives: To evaluate the diagnostic accuracy of a standalone artificial intelligence fracture detection software on foot and ankle radiographs, compared with board-certified musculoskeletal radiologists, with emphasis on midfoot injuries. Materials and Methods: This retrospective single-center diagnostic accuracy study included adult patients presenting to the emergency department with acute foot or ankle trauma. Radiographs were interpreted in real time, analyzed retrospectively by musculoskeletal (MSK) radiologists during the routine workflow and subsequently analyzed independently by an artificial intelligence system. The reference standard was structured clinical follow-up, complemented by cross-sectional imaging when the radiograph was equivocal. Diagnostic performance metrics and inter-reader agreement were calculated. Results: A total of 701 examinations (mean age, 42 ± 17 years; 376 men) were included; 319 fractures were identified, including 29 Chopart and 26 Lisfranc injuries. Overall sensitivity, specificity, and accuracy were 74.3%, 83.0%, and 79.0% for artificial intelligence, 84.0%, 95.5%, and 90.3% for radiologists, respectively (p < 0.0001; κ = 0.65). For Chopart and Lisfranc fractures, radiologists demonstrated higher sensitivity, while specificity remained excellent for both approaches, but the paired comparisons did not reach significance. Conclusions: Standalone artificial intelligence achieved high diagnostic performance for foot and ankle fracture detection on radiographs but was less sensitive than MSK radiologists for complex midfoot injuries.

Original Article Healthy knee cartilage T2 mapping assessed with GRAPPATINI and multi-echo spin-echo (MESE) at 3T: regional values, longitudinal repeatability and method agreement Bénédicte M. A. Delattre, Tom Hilbert, Halah Kutaish, Lindsey A. Crowe, Pierre-Alexandre Poletti, Jacques Menetrey, Didier Hannouche, Philippe M. Tscholl, Sana Boudabbous

Os centrale carpi is an uncommon accessory carpal bone. We report, to the best of our knowledge, the first case of imaging findings of “os centrale carpi bone bruising” simulating an acute scaphoid fracture. The various differential diagnoses of this entity are discussed. A 22-year-old man presented to our hospital with dorsolateral wrist pain following trauma. Radiography revealed a potential fracture line in the distal pole of the scaphoid and a fracture of the base of the ulnar styloid. Magnetic resonance imaging (MRI) revealed bone bruising of the os centrale carpi and a fracture of the ulnar styloid process. The objective of this case report is to present the imaging findings of os centrale carpi bone bruising, an uncommon occurrence in wrist trauma.

The objective of this study is to measure T2* relaxation time in the triangular fibrocartilage (TFC) disc in asymptomatic volunteers and evaluate its variation with factors such as age, hand dominance, sex, and ulnar variance, using a dedicated MRI sequence. The MRI protocol included anatomical sequences as well as a 3D ultra-short echo time (UTE)-T2* mapping sequence. A linear regression model was used to assess the potential influence of age, sex, and hand dominance on T2* values measured in the TFC disc and to evaluate the correlation between T2* values and ulnar variance. T2* relaxation time was positively correlated with age. The higher T2* relaxation times may reflect early degeneration of the fibrocartilage microstructure, which is associated with both biomechanical factors and the aging process. However, T2* was not significantly influenced by sex or hand dominance, nor was it correlated with ulnar variance (this later being limited by the fact that none of our subject had positive ulnar variance). In conclusion, UTE-T2* is a promising MRI technique showing positive correlation with age in the TFC of healthy subjects. These findings are a first step to establish normative T2* values and will help interpreting deviations observed in patient with suspected pathology in future studies.

Although minimally invasive surgery has significantly reduced the incidence of incisional hernia (IH) in colorectal procedures, the choice of specimen extraction site continues to pose a risk. This study explores how the location of extraction site influences the occurrence of IH in patients undergoing minimally invasive colorectal resections. We conducted a retrospective observational cohort study involving consecutive patients who underwent minimally invasive colorectal resection for colorectal cancer from 2013 to 2021. Patients with open surgery, previous hernia repair, reoperations during the study period or without imaging follow-up were excluded. The primary outcome measured was the CT-proven incidence of IH at the extraction site. A total of 191 patients were analyzed. Among them, 113 patients (59.2%) had a midline extraction site, while and 78 patients (40.8%) had an off-midline extraction. Midline extraction was preferably used during right and transverse colectomy (98% and 100% respectively), whereas off-midline were preferred in left hemicolectomy, sigmoidectomy, and anterior resection (55%, 88%, 95% respectively). Remarkably, the overall incidence of IH at the extraction site was 30.9% for midline extractions compared to 0% for off-midline extractions (p value < 0.001). The mean follow-up duration was of 3.3 ± 2.1 years. Multivariate logistic regression analysis revealed midline extraction as a significant risk factor for IH with a relative risk of 29.1 (95% CI 3.8–220.5, p value < 0.001). The findings highlight a substantial increase in the risk of IH associated with midline extraction sites. As such, it is crucial to advocate for fully minimally invasive colorectal resection using off-midline incision to enhance patient outcomes and reduce the risk of incisional hernias.

Background/Objectives: T1 relaxation time has been shown to be valuable in detecting and characterizing tumors in various organs. This study aims to determine whether native T1 relaxation time can serve as a useful tool in distinguishing sarcomas from benign tumors. Methods: In this retrospective study, patients with histologically confirmed soft tissue sarcomas and benign tumors were included. Only patients who had not undergone prior treatment or surgery and whose magnetic resonance imaging (MRI) included native T1 mapping were considered. Images were acquired using both 1.5 T and 3 T MRI scanners. T1 histogram parameters were measured in regions of interest encompassing the entire tumor volume, as well as in healthy muscle tissue. Results: Out of 316 cases, 16 sarcoma cases and 9 benign tumor cases were eligible. The T1 values observed in sarcoma did not significantly differ from those in benign lesions in both 1.5 T and 3 T MRIs (p1.5T = 0.260 and p3T = 0.119). However, T1 values were found to be lower in healthy tissues compared to sarcoma at 3 T (p = 0.020), although this difference did not reach statistical significance at 1.5 T (p = 0.063). At both 1.5 T and 3 T, no significant difference between healthy muscle measured in sarcoma cases or benign tumor cases was observed (p1.5T = 0.472 and p3T = 0.226). Conclusions: T1 mapping has the potential to serve as a promising tool for differentiating sarcomas from benign tumors in baseline assessments. However, the standardization of imaging protocols and further improvements in T1 mapping techniques are necessary to fully realize its potential.