PURPOSE:Rotational tibial component alignment represents a critical factor for proper patella tracking, optimal clinical outcome and preventing femorotibial mismatch. For osteoarthritic knees, substantial anatomical variability of tibia tubercle (TT) position exists. This common intraarticular tibial rotational deformity complicates decision-making and often requires compromises, which have contributed to the lack of consensus for optimal tibial component positioning. METHODS:An intensive literature search has been performed in multiple databases to identify relevant laboratory studies, imaging, clinical trials, surgical techniques and current practice. The selected 95 key articles formed the basis to summarize the complex biomechanics of the patellofemoral joint, high anatomical variability of TT position and current clinical practice for tibial component rotational alignment in total knee arthroplasty (TKA). RESULTS:More than 20 reference lines and methods have been described for tibial component rotational alignment, which can be separated into three different philosophies (anatomical, functional and self-rotational). Currently, there is no evidence that any approach yields superior patellar tracking, functional outcome and less anterior knee pain. In knees with normal TT positioning, most of these different techniques achieve satisfactory results. For TKA surgeons, it is important to identify the 30% of osteoarthritic knees with intraarticular tibial rotational deformities and correct them during surgery. CONCLUSION:This narrative review summarizes the complex patellofemoral joint biomechanics, the high variability of intraarticular tibia axial plane deformities, and current surgical strategies for tibial component rotational alignment. It further describes methods to detect and correct intraarticular tibial rotational deformities in TKA. LEVEL OF EVIDENCE:Level V.

Implant-associated infections (IAIs) remain a major challenge in orthopaedic surgery, causing substantial morbidity, mortality, and healthcare costs. Antimicrobial implant coatings have emerged as a promising preventive strategy, but their comparative clinical benefit remains unclear. This study aimed to evaluate the effectiveness of antimicrobial coatings in preventing IAIs and to compare their clinical performance to uncoated implants. A systematic review and network meta-analysis was conducted in accordance with PRISMA guidelines. Medline, Embase, Scopus, and Web of Science were systematically searched for comparative studies evaluating antimicrobial implant coatings for the prevention of orthopaedic IAIs. The primary outcome was the incidence of postoperative IAIs, while secondary outcomes included complications, site-specific infections, causative organisms, use of antibiotic prophylaxis, operative time, time to infection, and implant survival. Random-effects network meta-analysis, subgroup analyses, and assessment of publication bias were performed to synthesize and compare treatment effects across coating types. Twenty-six studies encompassing 3,592 patients were included, of whom 1,576 received coated and 2,016 uncoated implants. Coating technologies included Defensive Antibacterial Coating (DAC) hydrogel, gentamicin, iodine, silver, antibiotic-loaded calcium sulfate, and gold-silver-palladium alloy. Overall, infection rates were lower in coated implants (26.9

PURPOSE:This study aims to test whether week-long wrist accelerometry combined with deep learning can (i) distinguish healthy individuals from people with knee osteoarthritis (KOA), (ii) separate prodromal KOA from established KOA, and (iii) identify individuals who will receive a KOA diagnosis within 5 years. METHODS:We conducted a retrospective case-control study using the UK Biobank data set. After quality control, 102,120 participants with valid accelerometry were available; KOA was identified via ICD-10 M17.x codes (n = 7262). To reduce adiposity confounding, analyses were restricted to body mass index (BMI) ≥ 29, with controls matched to KOA on age, sex and BMI distributions. We used preprocessed, orientation-independent, hourly mean acceleration over a 24-h cycle and included month, sex, age and weight as covariates. A 1D convolutional neural network modelled daily activity profiles with embeddings for categorical covariates. Fivefold cross-validation assessed accuracy, macro F1, macro sensitivity and AUC. RESULTS:Balanced cohorts were formed for three tasks: healthy versus KOA (n = 3677 per class), prodromal versus diagnosed KOA (n = 1596 vs. 2081), and healthy vs prodromal within 5 years (n = 1369 per class). Daily activity patterns were similar across groups, with slightly lower daytime acceleration in KOA/prodromal participants. Model performance was moderate for healthy versus KOA (accuracy 63.5 ± 1.2%; AUC 0.672 ± 0.017) and healthy vs prodromal within 5 years (64.5 ± 0.5%; AUC 0.675 ± 0.019). Discrimination between prodromal and diagnosed KOA was close to random (54.6% ± 1.5%; AUC 0.552 ± 0.015). CONCLUSIONS:One week of wrist-worn accelerometry contains a reproducible signal associated with KOA and can flag elevated risk up to 5 years before diagnosis. Since existing KOA cannot be distinguished from prodromal KOA, it can be assumed that patients show altered movement patterns years before diagnosis. These findings highlight the clinical relevance of early, unobtrusive movement monitoring and support the potential of wearables as a scalable, low-cost component of population-level KOA screening. LEVEL OF EVIDENCE:Level II, prognostic study-lower-quality prospective cohort. The study uses a large, population-based prospective cohort (UK Biobank) with retrospective analytical methods; follow-up is high, but the study is a secondary analysis rather than a primary prospectively designed prognostic trial.

Background: Contamination of sterilized surgical instruments is not a typically suspected source of increased infection rate, especially if no abnormalities in the sterilization process are detected. Purpose/Hypothesis: The purpose of this study was to report increased infection rates after knee ligament reconstructions due to undetectable sterilization process errors leading to residual moisture, not limited to a specific surgical tool. It was hypothesized that (1) residual moisture on surgical tools due to autoclave overloading would not be detected by autoclave self-diagnostics, chemical and biological tests, or organoleptic assessment and (2) this kind of contamination may elevate infection rates, especially in knee intra-articular reconstruction procedures. Study Design: Case series; Level of evidence, 4. Methods: A retrospective analysis of increased postoperative knee infection rate between January 2013 and January 2015 was performed. The inclusion criteria were all articular procedures. The exclusion criteria were joint arthroplasties, fractures, and open joint wounds. Criteria defining postoperative joint infections were as follows: (1) pain and effusion relapse and loss of achieved range of motion; (2) opaque/cloudy fluid on arthrocentesis; (3) fever >37.5°C lasting ≥3 days; and (4) ≥2-fold elevation in C-reactive protein levels, with symptoms onset within 21 days postoperatively. A negative culture result did not exclude a postoperative joint infection diagnosis and treatment. The data were summarized, and the infection rates of given subgroups were compared with a 2-tailed Fisher exact test. A risk ratio (RR) with 95% CIs was calculated. Results: Out of 533 orthopaedic procedures screened for inclusion, 4 joint arthroplasties, 7 fractures, and 2 open joint wounds were excluded. The remaining 520 articular procedures were included in the study—118 knee cruciate ligament reconstructions, 130 knee nonreconstruction arthroscopies, and 272 knee extra-articular/other joints arthroscopic and sports procedures. A total of 21.2% of knee intra-articular ligament reconstructions were complicated by postoperative joint infections, compared with 1.5% of knee nonreconstruction arthroscopies (RR, 13.8 [95% CI, 3.3-56.9]; P < .001) and 0.4% of knee extra-articular/other joints arthroscopic and sports procedures (RR, 57.6 [95% CI, 7.9-420.4]; P < .001). The source of the increased infection rate was identified as residual moisture on surgical tools due to autoclave overloading. This residual moisture was not detected by autoclave self-diagnostics, chemical and biological tests, or organoleptic assessment. After reducing the insert of surgical tools in the autoclave, the infection rate in the next 2 years after knee reconstructive procedures returned to <1% ( P < .001). Conclusions: Our study demonstrated that residual moisture after the sterilization process may be an underestimated source of postoperative joint infections, undetectable in routine procedures and tests. Overcrowding of surgical equipment in the autoclave may be a root cause of this residual moisture identified. This kind of contamination may elevate the infection rate, especially in knee intra-articular reconstruction procedures.

Zusammenfassung Einleitung Die multimodale Therapie der Arthrofibrose umfasst sowohl nichtchirurgische als auch chirurgische Ansätze. Die medikamentöse Behandlung wird kontrovers diskutiert, da bislang keine standardisierte Therapie etabliert wurde. Material und Methoden Dieser Artikel gibt eine Übersicht über potenzielle Arzneimittel, die in der adjuvanten Therapie der Arthrofibrose Anwendung finden. Verschiedene Substanzgruppen für die adjuvante medikamentöse Behandlung der Arthrofibrose werden vorgestellt. Eine angemessene Schmerztherapie, vorzugsweise mit nichtsteroidalen Antirheumatika (NSAR), bildet die Basis der Behandlung. Antioxidanzien und Vitamine können oxidative Stressbelastungen bei einem geringen Nebenwirkungsprofil reduzieren. Am häufigsten werden die antifibrotischen Eigenschaften von Kortikosteroiden und Propranolol genutzt; diese Substanzen können jedoch ausschließlich im „off-label use“ angewendet werden. Schlussfolgerung Der Einsatz verschiedener Substanzen sollte individuell geprüft und stadiengerecht als adjuvante Maßnahme zusätzlich zu anderen Therapieformen angewendet werden.

Die isolierte patellofemorale Arthrose ist eine degenerative Erkrankung des Kniegelenks, die zu Schmerzen und teils immobilisierenden Funktionseinschränkungen führen kann. Ist die konservative Therapie ausgeschöpft, kann ein Gelenkersatz die Lebensqualität und Mobilität der betroffenen Patienten relevant verbessern. In solchen Fällen gilt es, spezifisch die am besten geeignete Knieprothese für den Patienten zu wählen. Dieser Artikel beleuchtet die Entscheidungsfindung zwischen patellofemoraler Prothese, Knietotalprothese und bikondylärem Ersatz (ohne Rückflächenersatz der Kniescheibe). Die patellofemorale Prothese kommt vor allem bei jüngeren Patienten zum Einsatz und kann bei korrekter Implantation zu guten Resultaten und Hinauszögern eines totalprothetischen Ersatzes führen. Bei älteren Patienten mit isolierter patellofemoraler Arthrose wird meist das gesamte Kniegelenk ersetzt und eine Knietotalprothese gewählt, da diese zuverlässiger zu guten Ergebnissen führt und mit einer geringeren Revisionsrate verbunden ist. In ausgewählten Fällen muss insbesondere bei stark ausgedünnter Patella auf einen Retropatellarersatz verzichtet werden.

Revision surgery after anterior cruciate ligament reconstruction (ACL-R) is hypothesized to be the result of an interplay between factors associated with the anatomy, physiological characteristics and environment of the patient. The multifactorial nature of revision ACL-R risk is difficult to quantify, and evidence regarding the independent roles of potentially important variables is inconsistent throughout the literature. Young patient age is often cited as one of the most prominent risk factors for reinjury after ACL-R. However, the association between a non-modifiable variable such as patient age and revision ACL-R risk is likely to be a spurious correlation due to the confounding effect of more important variables. From the perspective of healthcare professionals aiming to mitigate revision ACL-R risk through targeted interventions, awareness of factors like generalized joint hypermobility, bone morphology, muscle strength imbalances, and genetic factors is critical for the individualized risk assessment of patients with ACL injury. The aim of this current concepts article is to raise awareness of the essential anatomical, physiological, and activity-related risk factors associated with ACL injury and reinjury risk that are likely captured and confounded by patient age. LEVEL OF EVIDENCE: Level V.

Digital twin (DT) systems, which involve creating virtual replicas of physical objects or systems, have the potential to transform healthcare by offering personalised and predictive models that grant deeper insight into a patient's condition. This review explores current concepts in DT systems for musculoskeletal (MSK) applications through an overview of the key components, technologies, clinical uses, challenges, and future directions that define this rapidly growing field. DT systems leverage computational models such as multibody dynamics and finite element analysis to simulate the mechanical behaviour of MSK structures, while integration with wearable technologies allows real-time monitoring and feedback, facilitating preventive measures, and adaptive care strategies. Early applications of DT systems to MSK include optimising the monitoring of exercise and rehabilitation, analysing joint mechanics for personalised surgical techniques, and predicting post-operative outcomes. While still under development, these advancements promise to revolutionise MSK care by improving surgical planning, reducing complications, and personalising patient rehabilitation strategies. Integrating advanced machine learning algorithms can enhance the predictive abilities of DTs and provide a better understanding of disease processes through explainable artificial intelligence (AI). Despite their potential, DT systems face significant challenges. These include integrating multi-modal data, modelling ageing and damage, efficiently using computational resources and developing clinically accurate and impactful models. Addressing these challenges will require multidisciplinary collaboration. Furthermore, guaranteeing patient privacy and protection against bias is extremely important, as is navigating regulatory requirements for clinical adoption. DT systems present a significant opportunity to improve patient care, made possible by recent technological advancements in several fields, including wearable sensors, computational modelling of biological structures, and AI. As these technologies continue to mature and their integration is streamlined, DT systems may fast-track medical innovation, ushering in a new era of rapid improvement of treatment outcomes and broadening the scope of preventive medicine. Level of Evidence: Level V.

Phenotyping of the knee joint has been established as an important pre- and postoperative measure to better describe the individual knee joint in terms of alignment, laxity, morphology, and kinematics. Therefore, this narrative review aims to provide a comprehensive analysis of the current literature on phenotyping to understand both the major benefits and the existing limitations. This narrative review was conducted according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. A total of 38 studies were included. The included papers were categorized into two main groups, CPAK and functional knee phenotyping (FKP), of which the second group could be further subdivided into alignment, laxity, and morphology. The advantages and limitations were noted. Understanding the underlying knee phenotype in OA knees is crucial for a more personalized approach in TKA. The standardized use of the current phenotype systems, whether CPAK or FKP is key. The advantage of CPAK is that it is easy to apply in daily practice, but it is of limited value because it may omit a lot of important information. FKP, on the other hand, contains many more parameters, which makes it difficult for the majority of surgeons to integrate into their routine planning. However, as the knee is defined by multiple parameters in three dimensions, it is of utmost importance to integrate as many factors as possible for an optimal alignment in TKA.

Die Behandlung des patellofemoralen Gelenkknorpelschadens/der Arthrose am Knie bietet eine Reihe von Therapiemöglichkeiten. Durch den vorgestellten Algorithmus wird eine Entscheidungshilfe bei der Vorgehensweise gegeben. Die Korrektur einer Achsabweichung bzw. eines Malalignements und die genaue Beurteilung einer Patellainstabilität stellt für die erfolgreiche Therapie eine Grundvoraussetzung dar. Weiterhin spielen die Defektgröße und Kontextfaktoren, wie z. B. das Alter und vorrausgegangene Therapien, eine wichtige Rolle für die Wahl der besten operativen Vorgehensweise. Neben den typischen Knorpelersatzverfahren kommen Miniimplantate zur Behandlung lokalisierter Schäden zum Einsatz. Bei fortgeschrittener Arthrose besteht die Option zum isolierten patellofemoralen Ersatz durch ein Inlay- oder Onlay-Implantat.

Septic arthritis is a serious orthopedic emergency that can lead to irreversible chondrolysis and joint destruction if not treated promptly. Although Staphylococcus aureus is the most common pathogen, atypical bacteria, especially injuries inflicted by animals, can cause severe septic arthritis. Recognizing the risk of infection from even seemingly minor injuries during initial inspection is crucial to prevent fulminant septic arthritis. Diagnostic tools such as blood cultures and synovial fluid aspiration are key to identifying the causative bacteria and guiding antibiotic therapy. A Swiss, 26 years old, woman got pecked by a rooster and suffered an injury to her right knee. The patient’s symptoms, blood analysis, and joint aspiration confirmed the diagnosis of septic arthritis of the knee. Empiric antibiotic treatment with amoxicillin and clavulanic acid was started. Arthroscopic debridement and dilution was initiated. The arthroscopic view showed damage to the right medial femur condyle, which was overlooked by the medical staff during the patient’s initial examination. The patient recovered quickly and showed no more restrictions 6 weeks after trauma. This case highlights the importance of recognizing the risk of infection, even from seemingly small injuries such as a rooster peck, to prevent fulminant septic arthritis. Further, this case demonstrates the importance of not underestimating a penetration wound by inspection only. Thorough clinical examination and wound exploration or saline load test can help to assess the depth of penetrating wounds. Nevertheless, rapid surgical and antibiotic treatment ensured a positive outcome for the patient in the case of this orthopedic emergency.

PURPOSE:While bony alignment phenotype reconstruction became an important part of personalised knee arthroplasty, the knowledge on laxity phenotypes (LPs) is still limited. This study aimed to calculate individual LPs and assess their changes based on bony decisions from different alignment workflows. METHODS:Radiographs and computer-assisted surgery data of 86 knees were imported into a validated knee alignment simulator. Individual bony parameters (medial proximal tibial angle, lateral distal femoral angle and posterior condyle axis) were first introduced. By that, the patient-specific bony phenotype (B-FKP) was implemented, and based on these simulations, the patient-specific laxity phenotype (L-FKP) was defined, calculated and analysed for the total group, as well as for all Coronal Plane Alignment of the Knee (CPAK) subgroups. CPAK I and IV were summarised as varus group; II and V as neutral, and III, VI and IX as valgus group. Identical calculations were then compared for the MA and L-FKP of both workflows. LP was calculated in both extension (L-FKPext) and flexion (L-FKPflex), and a pattern matrix was constructed for all possible L-FKP combinations, enabling a comprehensive distribution analysis. Statistical differences between subgroups and B-FKP and mechanical alignment (MA) workflows were calculated. RESULTS:B-FKP showed a minimal, non-significant difference for L-FKPext in all subgroups; however, a huge variability in L-FKP pattern analysis. In contrast, MA showed a significant difference for L-FKPext in all subgroups, with a high correlation between L-FKPext and hip-knee-ankle angle. While in MA, 98% of knees showed lateral laxity (L-FKPflex-latlax), in B-FKP, only 56% were L-FKPflex-latlax, with a large variability (31% L-FKPflex-neutr and 13% L-FKPflex-medlax). CONCLUSIONS:Personalised bony resections reduce gap differences for LPext and LPflex independent of the deformity. MA showed a high correlation between deformity and LPext in extension and a uniform lateral laxity in flexion. L-FKP analysis can help to understand the individuality of knees from a soft tissue aspect. LEVEL OF EVIDENCE:Level III.

PURPOSE:Robotic arm-assisted total knee arthroplasty (raTKA) has demonstrated several advantages over manual TKA (mTKA), including enhanced early recovery. Reduced soft tissue trauma and avoidance of femoral intramedullary canal opening have been hypothesised to lower the systemic inflammatory response. However, findings from previous small-cohort studies have been inconsistent. This study aimed to evaluate postoperative systemic inflammation in a large patient cohort. METHODS:Patients who underwent raTKA using the Mako® system were matched with patients who received mTKA based on gender, American Society of Anesthesiologists score, age and body mass index. This matching process resulted in two comparable cohorts, each comprising 344 patients. Blood samples were collected preoperatively, 6 h postoperatively, and on postoperative Days 3 and 5. Measurements included C-reactive protein (CRP), white blood cell count (WBC) and calculated blood loss. RESULTS:The highest CRP levels were observed on postoperative Day 3 in both groups. The median CRP increase was significantly lower in the raTKA group compared with the mTKA group on Day 3 (4.4 vs. 5.3 mg/dL; p = 0.002) and slightly lower on Day 5 (3.5 vs. 3.8 mg/dL; p = 0.349). The WBC count peaked at 6 h postoperatively in both groups before steadily declining, with no significant difference between groups. The median operation time was significantly longer in the raTKA group (92 vs. 86 min; p < 0.001). Despite a longer surgical duration, the median blood loss was significantly lower in the raTKA group (653 vs. 729 mL; p = 0.005). CONCLUSION:In the largest comparative analysis to date, raTKA was linked to significantly lower postoperative CRP levels than mTKA. Reduced soft tissue trauma, avoidance of femoral intramedullary canal violation and significantly lower blood loss may all contribute to a diminished systemic inflammatory response, potentially explaining the improved early functional outcomes observed with raTKA. LEVEL OF EVIDENCE:Level III, retrospective comparative study.

Introduction:The sit-to-stand (STS) movement represents a mechanically demanding task, particularly informative in patients with knee osteoarthritis. While three-dimensional optoelectronic motion capture is the gold standard for analyzing joint biomechanics, the influence of protocol selection remains poorly characterized in the context of STS. This study investigated protocol-induced variability in knee kinematics and kinetics by evaluating two widely used marker sets: the anatomical-based IOR and the cluster-based CAST, each combined with either inverse kinematics or a six degrees-of-freedom joint model. Materials and Methods:Twenty-four patients (mean age of 67 ± 5 years and BMI of 28.9 ± 3.8 kg/m2) with end-stage KOA (Kellgren-Lawrence grade 3 or 4) performed three STS trials, and biomechanical outputs were compared across the four resulting protocols using Mean Absolute Variability (MAV), Mean Absolute Differences (MAD), and Statistical Parametric Mapping (SPM). Results:Results revealed substantial variability across protocols, with the highest discrepancies observed in the sagittal plane: peak MAV reached 23.99° for knee flexion angle and 0.24 Nm/kg for knee flexion moment. Frontal and transverse parameters also showed clinically meaningful differences, particularly for knee adduction and internal rotation angles, with MAD values exceeding established thresholds. Differences were amplified when both markers set, and modeling strategy varied. In this context, cluster-based configurations showed reduced variability. SPM analyses revealed temporally localized differences, particularly at the initiation and final stabilization phases of the movement. Conclusion:These findings emphasize the critical role of protocol selection in motion analysis and its direct impact on the interpretation of knee biomechanics during functional tasks, highlighting the importance of adopting consistent and robust methodological frameworks to ensure clinical reliability and cross-study comparability. Clinical Trial Registration:https://clinicaltrials.gov/, identifier NCT06634654.

Die Patella baja stellt eine komplexe Herausforderung für den behandelnden Orthopäden und Unfallchirurgen dar. Sie kann akut in Folge von Verletzungen und postoperativen Veränderungen der Gelenksymmetrie entstehen, sowie sich auch im Verlauf nach operativen Eingriffen und Verletzungen entwickeln. Klinisch fällt sie insbesondere durch einen anterioren Knieschmerz sowie oft auch eine Einschränkung des Bewegungsumfangs auf. Die Diagnosestellung und Quantifizierung erfolgen anhand einer lateralen Bildgebung (Röntgenaufnahme/Magnetresonanztomographie [MRT]/Computertomographie [CT]) und unterschiedlichen Indices, die die Höhe der Kniescheibe beschreiben können. In Zusammenschau ist zwischen einer echten („true patella baja“) und vermeintlichen Patella baja („pseudo patella baja“), die vor allem nach Knieendoprothetik durch eine Verschiebung der Gelenklinie zustande kommt, zu unterscheiden. Die operativen Therapieformen erfolgen ursachenabhängig mittels Wiederherstellung der Kontinuität des Streckapparats im akuten Fall oder mittels Optimierung der Patellahöhe in Form einer proximalisierenden Tuberositas-tibiae-Osteotomie oder in der Revisionsendoprothetik durch die Wiederherstellung der Gelenklinie.

PURPOSE:To compare clinical outcomes in varus-aligned patients undergoing cruciate-retaining total knee arthroplasty (TKA) with mechanical alignment (MA) versus unrestricted kinematic alignment (KA). The hypothesis was that KA would yield superior outcomes, and that preserving joint line obliquity-regardless of alignment technique-would be associated with better results. METHODS:A retrospective analysis of prospectively collected data from 140 KA and 209 MA TKA cases was performed. Inclusion criteria were: end-stage varus osteoarthritis (aHKA < 178°), MA or unrestricted KA TKA and ≥ 1-year follow-up. Exclusion criteria included prior major surgery (osteotomies, fractures) on the affected limb, inadequate preoperative full-length radiographs, or post-operative complications unrelated to alignment strategy. Patients were categorised by CPAK phenotype (I, IV and VII) based on the joint line obliquity. Clinical outcomes at 1-year follow-up were assessed using the Knee Society Score (KSS) pt.1 and 2, Oxford Knee Score (OKS), SF-12, and Forgotten Joint Score (FJS). ANOVA was used to compare results of MA and KA in the overall varus population, and in CPAK subgroups. Statistical significance was set at p < 0.05. RESULTS:KA led to significantly higher KSS pt.1 (84.6 ± 15.3 vs. 73.9 ± 18.9; p < 0.001) and FJS (90.5 ± 15.3 vs. 80.4 ± 15.8; p < 0.001) than MA. In CPAK I patients, KA outperformed MA in KSS pt.1 (83.5 ± 16.2 vs. 74.9 ± 19.1; p < 0.001) and FJS (89.8 ± 15.5 vs. 80.7 ± 17.8; p < 0.001). No differences were found between KA and MA in CPAK IV patients (p > 0.05). KSS pt.1 (80.1 ± 13.8) and FJS (86.5 ± 18.1) achieved with MA in CPAK IV were significantly higher than in both the overall varus aHKA group and CPAK I patients treated with MA (p < 0.05). CONCLUSIONS:Cruciate-retaining unrestricted KA yields better clinical outcomes compared to MA in varus aHKA patients, and in the CPAK I subgroup. In CPAK IV, preserving joint line obliquity leads to similar outcomes with both MA and KA. LEVEL OF EVIDENCE:Level IV.

PURPOSE:This systematic review was conducted to evaluate the current literature on metal hypersensitivity in patients undergoing joint arthroplasty. The aims of the study were to report diagnostic tools used to assess metal hypersensitivity and to report complications arising in patients who are hypersensitive to nickel or other metals performing joint arthroplasty. Given the potential impact on implant longevity and patient outcomes, understanding the clinical relevance of metal hypersensitivity is crucial for optimising surgical decision-making. METHODS:This systematic review adheres to PRISMA guidelines and evaluates the variability in diagnostic approaches and the challenges in clinical management. Included in this review were studies involving patients sensitive to nickel or other metals undergoing joint arthroplasty. Eligibility criteria focused on commonly employed diagnostic tools and associated complications. A comprehensive literature search was conducted across Medline, EMBASE, Scopus, CINAHL, and CENTRAL databases. The methodological quality of the included studies was assessed using the Joanna Briggs Institute Critical Appraisal tool for case series and the ROBINS-I tool for case-control studies. RESULTS:Twenty-four articles met the inclusion criteria and were included in this systematic review. A total of 4865 patients undergoing joint arthroplasty were selected. Diagnostic tools included patch testing, lymphocyte transformation test (LTT), and medical history assessment. Variability in time point of testing and diagnostic protocols was noted. Complications including joint pain, swelling, reduced range of motion, and implant failure were reported in 12 studies. Clinical outcomes varied widely: some studies showing no significant differences between hypersensitive and non-hypersensitive patients, while others reported increased pain and reduced joint function. CONCLUSION:There is a lack of a standardised protocol for diagnosing metal hypersensitivity, leading to uncertainty regarding test selection and timing. This inconsistency leads to variability in reported outcomes, with limited studies focusing on post-surgical hypersensitivity in patients. LEVEL OF EVIDENCE:Level III, systematic review.

Total knee arthroplasty (TKA) has become one of the most widely performed procedures for end-stage osteoarthritis, yet patient satisfaction continues to lag behind that of hip replacement. Advances in robotics and artificial intelligence have increased surgical precision, but improved accuracy alone does not guarantee better outcomes. The challenge lies in defining appropriate alignment and balancing strategies that respect each patient's unique anatomy and soft-tissue characteristics rather than relying on uniform targets. Personalized alignment has emerged as a promising concept, aiming to restore individual bony geometry and preserve native laxity patterns across all planes. However, questions remain about what constitutes "normal" versus "pathologic," especially given anatomical and demographic differences between populations. Data derived largely from Caucasian cohorts may not be directly transferable to Asian patients, whose morphologies often differ substantially. This underscores the need for region-specific research, robust data collection, and harmonized workflows supported by advanced analytic systems. Only through global collaboration and objective evidence can reliable boundaries for personalized techniques be established. By integrating precision technology with truly individualized surgical planning, the next phase of TKA development seeks to raise functional outcomes and patient satisfaction worldwide.

AbstractIntroductionKinematic alignment (KA) in total knee arthroplasty (TKA) is by definition a pure femoral resurfacing procedure aiming to restore the individual prearthritic anatomy. However, when a 2 mm compensation is systematically used on the worn side, the variability in cartilage thickness in the unworn compartment might alter the accuracy of the technique. This study aimed to validate two intraoperative femoral cartilage thickness measurement techniques by comparing them to the photographic method, which measures cartilage thickness through pixel analysis of bone‐cut images. The study hypothesized that the two intraoperative methods are comparable and similarly accurate within 0.5 mm of the photographic method.MethodsSeventy cartilage thickness measurements from seventy patients with end‐stage knee osteoarthritis were prospectively collected. Two intraoperative techniques were evaluated: the electrocautery tip method (Method A) and the ruler method (Method B), performed before and after distal femoral bone resections, respectively. The postoperative photographic analysis (Method C) served as the reference method. Measurements were rounded to the nearest 0.5 mm for consistency. Data were analyzed using Kruskal–Wallis test, Wilcoxon rank‐sum tests, Spearman's rank correlation, percentage of agreement and intraclass correlation coefficients (ICCs).ResultsNo significant differences were observed between Method A and Method B in measuring femoral cartilage thickness. Agreement with Method C was 100% for Method B and 85% for Method A. In the 15% of discordant cases, Method A overestimated the measurements by one category of 0.5 mm compared to Method C. Correlation coefficients between the methods were high (ρ = 0.88−1.0). Intra‐ and interobserver reliability was high for all methods (ICCs 0.91–0.95).DiscussionBoth intraoperative methods are reliable and comparable to the photographic method when rounded to the closest 0.5 mm, with no significant differences among them. The electrocautery method has the added advantage of measuring cartilage thickness before bone cuts are performed.Level of EvidenceLevel IV.