Pierre-Alban Bouché

Background: Questions/purposes: Methods: Results: Conclusions: Level of evidence: Level II, systematic review.

This study aimed to provide a nationwide assessment of the incidence, risk factors, morbidity, and mortality of hip and knee periprosthetic fractures in France over the past decade, and to project their future burden up to 2070 under different epidemiological scenarios. This nationwide retrospective study used the French National Health Data System to identify all patients who underwent reoperation for hip or knee periprosthetic fracture in France between January 2015 and December 2024. Fracture episodes occurring within three months of each other were considered a single event. Annual incidence rates were calculated per 100,000 inhabitants, and cumulative incidences of complications and mortality were assessed at three months and one year. Long-term projections were generated for 2030 to 2070 using two scenarios: a static model assuming stable incidence, and a dynamic model extrapolating the 2015 to 2024 linear trend adjusted for demographic forecasts. Over the ten-year period, 15,029 periprosthetic fractures were identified. The mean age was 81 years (SD 11) and 70% (10,571) of patients were female. The incidence doubled from 1.73 to 3.94 per 100,000 inhabitants between 2015 and 2024. Mortality reached 8% at three months and 16% at one year, primarily associated with older age (HR 1.1) and higher comorbidity burden (HR 1.2). Postoperative complications occurred in 16% of patients within three months, including pressure ulcers, procedure-related complications, and cardiovascular events. Projections indicated a 33% and 248% increase in periprosthetic fractures by 2070 under the static and dynamic incidence scenarios, respectively. The incidence of periprosthetic fractures in France has risen steadily and is expected to increase substantially in the coming decades, driven by demographic ageing. Given their high morbidity and mortality, optimizing perioperative and post-fracture care, along with implementing measures to prevent both fractures and related complications, should be considered a public health priority.

Ce travail de thèse porte sur l’évaluation de la qualité de l’acte chirurgical dans les prothèses totales de genoux. Elle s’articule en deux parties. La première s’intéresse à l’évaluation de deux aspects techniques dans les prothèses totales de genoux à l’aide de méta-analyses en réseaux. La seconde à l’évaluation de l’apprentissage de nouvelles procédures en orthopédie, notamment dans la technique de l’arthroplastie totale du genou. La première méta-analyse en réseau a évalué les voies d’abords dans les prothèses totales de genoux. Nous avons observé que la voie subvastus améliorait les mobilités dans les six premiers mois postopératoires sans différence sur les scores fonctionnels à terme. La voie parapatellaire interne diminuait la durée opératoire, comparée aux autres voies d’abord chirurgicales. La durée d’hospitalisation des patients opérés par voie mini-parapatellaire interne était inférieur à celle des patients opérés par une autre technique. Au vu des résultats, aucune voie d’abord chirurgicale médiale pour les prothèses totales de genoux ne semble clairement supérieure à une autre. La deuxième méta-analyse en réseau a évalué les guides de coupes dans les prothèses totales de genoux. Nous avons observé que la navigation permettait de diminuer le taux de valeurs aberrantes d’alignement du membre inférieur et de positionnement des implants prothétiques dans les plans frontal et sagittal comparée au guide de coupe standard, mais augmentait le temps opératoire d’environ 20 minutes. À la vue de ces résultats, nous ne pouvons pas recommander l’utilisation d’un ancillaire de coupe particulier, puisque les différences observées sur les critères radiologiques n’ont pas eu de répercussions sur les scores cliniques. La deuxième partie de ce travail s’est intéressée à l’évaluation de l’apprentissage de nouvelles procédures en orthopédie et notamment dans les prothèses totales de genoux. En effet de nouvelles technologies en chirurgie prothétique du genou se développent et l’évaluation et la validation de leur apprentissage est nécessaire. Une revue de la littérature sur les différentes méthodologies de courbes d’apprentissage utilisées en orthopédie a été menée. Six méthodologies différentes ont été identifiées dans les différentes publications afin de traiter les courbes d’apprentissage en orthopédie. Le LC-CUSUM semble être la méthode la plus simple, la plus flexible et la plus robuste pour modéliser une courbe d’apprentissage. Enfin, nous présentons dans la dernière partie de cette thèse le développement d’un test statistique afin de pouvoir comparer deux méthodes d’apprentissage entre elles. Après avoir validé les performances du test statistique, une application sur des données réelles d’apprentissage de connaissances a été proposée. Afin que ce test soit validé de manière formelle, une application clinique sur un volume de données plus important est nécessaire. Concernant l’évaluation clinique des prothèses totales de genoux, la méta-analyse en réseau est une méthodologie adaptée. En effet, il est difficile de mettre en place un essai randomisé comportant quatre ou cinq bras d’une intervention chirurgicale. Elles permettent d’extraire des données et de réaliser des comparaisons jamais effectuées auparavant dans la littérature en réutilisant ces mêmes données et en les synthétisant afin de répondre à une question précise. Concernant l’évaluation de l’apprentissage en orthopédie, il n’y a aucune recommandation méthodologique. Le LC-CUSUM test semble être la meilleure méthode pour modéliser une courbe d’apprentissage. Aucun test statistique n’existe permettant de comparer deux courbes d’apprentissage entre elles. Nous en avons élaboré un mais qui nécessite une validation lors d’une application clinique plus importante.

Periprosthetic joint infections (PJIs) are a serious complication in both primary arthroplasty and revision arthroplasty, posing a major challenge in orthopaedic surgery and creating a substantial financial burden. This literature review examines the current knowledge on PJI prediction, diagnosis and prognosis, with a focus on scoring systems and machine learning (ML) tools developed to improve their management. We conducted a narrative literature review by searching Medline, CENTRAL and Embase up to October 1, 2024, with independent dual-reviewer screening. Nine non-randomized studies were included, covering 297,981 prostheses and 7,190 PJIs. Two studies assessed prediction based on patient history but highlighted the need for refinement and multi-centre prospective validation. Five studies evaluated ML in diagnosis, showing promising accuracy, yet requiring broader validation in larger, more diverse clinical contexts. Two studies addressed prognosis, but models remain limited in providing individualized, treatment-specific insights. The development of ML models represents an interesting approach, given the rising prevalence of PJIs and the need for better management. However, available studies face important limitations, including small sample sizes, lack of external validation and limited transparency regarding parameters and models. To make ML tools clinically relevant, future research should prioritize external validation, larger multi-centre prospective studies and transparent reporting. Ultimately, robust ML models have the potential to enhance PJI management, improve patient outcomes and reduce healthcare costs.

Aims: This registry-based study aimed to evaluate the long-term survivorship of dual-mobility components (DMCs) compared to conventional components (CCs) in primary total hip arthroplasty (THA), and to assess potential adverse effects, particularly in younger patients (aged < 75 years). Methods: Data from 58,314 primary THAs recorded between January 2006 and December 2023 in the French national SOFCOT/RENACOT registry were analyzed, including 25,545 DMCs (46%). The primary outcome was revision for any cause. Kaplan-Meier survival curves and Cox proportional hazards models were used to compare implant survivorship, adjusting for age, sex, primary diagnosis, and fixation method. Results: Among the 25,545 primary THAs performed with a DMC, 284 revisions (1.1%) were recorded. In adjusted Cox regression analysis, DMC use was not significantly associated with an increased risk of revision compared to CCs (hazard ratio 0.83 (95% CI 0.66 to 1.04); p = 0.118). Periprosthetic fracture was the leading cause of revision in the DMC group (98/284, 34.5%), occurring significantly more frequently than in the CC group (77/493, 15.6%; p < 0.001), while dislocation-related revisions were less common with DMCs. Overall, the combined proportion of revisions due to dislocation or fracture was lower in the DMC group (112/284, 39.4%) than in the CC group (254/493, 51.5%). No risk factors for implant failure were identified in multivariable Cox regression analysis. Conclusion: DMCs provide excellent long-term survivorship and effectively reduce the risk of dislocation in primary THA. Although a higher incidence of periprosthetic fractures was observed with DMCs, the overall outcomes support their safe and effective use. Nevertheless, ongoing surveillance remains important to monitor these risks. Cite this article: Bone Joint J 2026;108-B(3):294–301.

Background: Periprosthetic femoral fractures (PFFs) are an increasingly common indication for revision total hip arthroplasty (THA). While patient-related risk factors are well documented, the influence of femoral stem design on PFF risk remains poorly characterized. In this study using nationwide data, we assessed the association between stem design and PFF risk. Methods: We analyzed 182,118 primary THAs (performed from 2015 to 2023) from the Swiss National Joint Registry (SIRIS). Cementless stems were categorized according to the Kheir classification, and cemented stems were categorized as double-tapered polished, triple-tapered polished, composite-beam, or custom. A multivariable Cox regression model, including variables such as age, sex, American Society of Anesthesiologists (ASA) class, body mass index (BMI), surgical indication, prior ipsilateral hip surgery, stem design, collar, dual-mobility cup, bearing, and head size, was analyzed. Hazard ratios (HRs) with 95% confidence intervals (CIs) are reported. Results: Among 182,118 THAs (mean patient age, 68.9 ± 11.5 years; female sex in 53.1% of cases), 1,226 (0.7%) were complicated by PFF. The cumulative incidence of PFF reached 0.7% at 5 years and 1.3% at 10 years. Higher PFF risk was associated with an age of 75 to 84 years (HR = 1.68 [95% CI = 1.44 to 1.96]) and ≥85 years (HR = 1.86 [95% CI = 1.47 to 2.35]), ASA class of 3 to 5 (females, HR = 1.70; males, HR = 1.73), BMI of 2 (HR = 1.61) or ≥40 kg/m ² (HR = 1.64), prior ipsilateral hip surgery (HR = 1.32), and use of a dual-mobility cup (HR = 1.56). Elective procedures (HR = 0.36) and collared stems (HR = 0.26) were associated with a lower risk. Compared with cementless type-3 stems, cementless type-7 (anatomic) stems showed a higher risk of PFF (HR = 1.88), whereas cementless type-1B (HR = 0.62) and composite-beam cemented stems (HR = 0.45) were protective. Conclusions: In this large nationwide registry study, femoral stem design independently influenced PFF risk after primary THA. Cementless anatomic stems increased the risk, whereas composite-beam cemented stems and the presence of a collar conferred a protective effect. These findings support personalized implant selection, particularly for older patients or those with frailty. Level of Evidence: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.