Sebastien Lustig

SICOT-J • February 27, 2025

Luca Andriollo, Pietro Gregori, Christos Koutserimpas, Elvire Servien, Cécile Batailler, Pascal Kouyoumdjian, Sébastien Lustig

Total knee arthroplasty (TKA) in valgus knee deformities presents unique challenges, including alignment, soft tissue balance, and implant positioning. The lateral approach offers advantages over the traditional medial approach by improving direct access, patellar tracking, and soft tissue preservation. Robotic-assisted TKA enhances precision, ligament balancing, and patient-specific alignment strategies, such as functional knee positioning (FKP). This study describes a surgical technique integrating the lateral approach with robotic-assisted TKA using FKP principles. The technique is based on an image-based robotic system, ensuring accurate preoperative planning, intraoperative adjustments, and optimized prosthetic placement. Key intraoperative steps, including bone resection strategies, soft tissue balancing, and trial component evaluations, are detailed. The lateral robotic approach with FKP was found to be effective and reproducible, allowing for precise implant alignment and optimized soft tissue balance in valgus knees. This method minimizes the need for extensive lateral releases, preserves vascularity, and ensures postoperative stability. The combination of the lateral approach, robotic-assisted TKA, and FKP represents a promising strategy for valgus knee deformities. Further long-term studies are needed to validate the durability and functional benefits of this technique.

Sicot-J • May 07, 2025

Thomas Papadimos, Scott Pappada, Jacob Alexander, Pavlos Altsitzioglou, Theodosis Saranteas, Sebastien Lustig, Andreas Mavrogenis

Orthopaedic surgical operations are associated with significant post-operative pain, often managed with opioids, which carry risks of adverse effects and dependency. Magnesium sulfate, a NMDA receptor antagonist with analgesic and muscle relaxant properties, has emerged as a potential adjunct to improve pain control and reduce opioid consumption in orthopaedic procedures. Current evidence supports magnesium sulfate as a valuable adjunct in orthopaedic pain management, particularly in reducing opioid consumption and enhancing muscle relaxation. However, heterogeneity in study design, administration protocols, and patient populations warrants cautious interpretation. Monitoring for side effects such as hypotension and respiratory depression remains essential. Further high-quality, standardized trials are needed to optimize dosing strategies and confirm long-term benefits.

The Bone & Joint Journal • April 30, 2025

Clement Favroul, Florian Voirin, Constant Foissey, Cecile Batailler, Sébastien Lustig

Periprosthetic fractures (PPFs) are a significant complication in total hip arthroplasty (THA), with their incidence varying from 0.1% to 5.2% in registries. The use of a collared femoral stem may reduce the risk of PPF by enhancing the distribution of load and the stability of the implant. The aim of this study was to compare the effect of collared versus collarless stems on the incidence of PPFs in a large cohort of patients. This retrospective study involved all primary THAs performed in a single centre between 1 January 2010 and 31 December 2020. Of the 2,182 THAs performed in 1,767 patients, 559 in 447 patients were excluded for the following reasons: having cemented stems, patients with a femoral neck fracture, dysplasia of the hip, or an oncological indication for surgery. A total of 1,623 THAs in 1,320 patients were included. The data which were collected included the patients' demographics, the surgical approach, the implant characteristics, and the incidence of PPF. Univariate and multivariate analyses were conducted using the Bursac's logistic regression model considering factors such as sex, age, BMI, surgical approach, and the presence of a collar. There were nine PPFs within 90 days of surgery: five in the collared stem group (0.4%) and four in the collarless stem group (1.6%). Multivariate analysis revealed that the presence of a collar was the only significant independent predictive factor of a reduced rate of PPFs (p = 0.048). Other factors such as sex, age, BMI, and surgical approach did not show significant correlations. The collared stem was a protective factor against early femoral PPF when cementless stems were used in primary THA. These results support the preference for collared versus collarless cementless stems, particularly in patients who are at a high risk of PPF, to enhance the initial stabilty of the stem and reduce complications.

Sicot-J • April 23, 2025

Christos Koutserimpas, Pietro Gregori, Enejd Veizi, Luca Andriollo, Elvire Servien, Cécile Batailler, Sébastien Lustig

Background: Under functional knee positioning (FKPos) principles, residual varus or valgus alignment of the tibia and femur may be maintained, resulting in loading conditions that differ from those observed with mechanical alignment. Consequently, there is a need for evidence regarding implant fixation (cemented or cementless) in this context. This study aimed to evaluate the impact of implant fixation type (cemented versus cementless) on clinical outcomes, complications, and implant survival in robotic-assisted total knee arthroplasty (TKA) guided by FKPos principles. Methods: A retrospective comparative analysis of 393 patients who underwent robotic-assisted primary TKA was performed. Patients were divided into two groups: cemented (n = 85) and cementless (n =276) fixation. Radiographic alignment, functional outcomes using the Knee Society Score (KSS) and Forgotten Joint Score (FJS), complication rates, and implant survival were assessed at a minimum 2-year follow-up. Subgroup analyses based on femoral and tibial fixation types were also conducted. Results: Both fixation methods achieved comparable functional outcomes (KSS and FJS) and implant survivorship, with no significant differences in revision rates. Hematomas were significantly more frequent in the cementless group (12.32% vs. 8.24%, p = 0.02). Subgroup analyses of femoral and tibial implants showed no significant differences in functional outcomes. Conclusions: This study is the first to assess the influence of fixation type on outcomes in robotic-assisted TKA performed under FKPos principles. Both cemented and cementless fixation methods are safe and effective.

Sicot-J • April 20, 2025

Luca Andriollo, Giovan Mazzella, Christos Koutserimpas, Pietro Gregori, Elvire Servien, Cécile Batailler, Sébastien Lustig

Unicompartmental knee arthroplasty (UKA) compared to total knee arthroplasty, offers several benefits, though it is associated with a higher revision rate, primarily due to suboptimal implant positioning. Recent advances in robotic-assisted techniques have contributed to more personalized and reproducible procedures. Functional Positioning (FP), a three-dimensional alignment concept, introduces a tailored approach based on a surgical technique that is both effective and reproducible. This article presents a step-by-step surgical technique for medial UKA using FP principles in combination with an image-based robotic system. The technique ensures accurate preoperative planning, real-time intraoperative adjustments, and precise component placement. The key steps of this surgical technique include achieving congruent contact points between the femur and tibia under load across the full range of motion, positioning the implant based on the compliance of the medial soft tissues, planning for a targeted laxity that results in an "eagle-wing" appearance, and the use of robotic tools to map cartilage for optimal resurfacing. Future studies will help refine FP strategies and further optimize outcomes in these patients.