Search Results (195)

Background/Objectives: Total knee arthroplasty (TKA) relieves pain and restores function for most patients with end-stage knee disease; yet, a clinically important minority are left with persistent pain, stiffness or both despite well-fixed, well-aligned implants. These “hidden failures” are poorly captured by implant survivorship but drive disability, dissatisfaction and disproportionate cost—stiff knees incur roughly 1.5–7.5 times the two-year treatment costs of non-stiff knees. This review integrates three usually separate studies within one phenotype-based framework. Methods: A structured comprehensive narrative review and thematic synthesis was undertaken; PubMed/MEDLINE, Web of Science and Google Scholar were searched between 30 October 2025 and 1 May 2026, identifying 467 records, of which 239 met the eligibility criteria and informed the synthesis. Results: Clinically meaningful chronic pain affects roughly 10–30% of recipients and stiffness approximately 1–7%, with high-impact chronic pain persisting in about one-in-five and neuropathic features in a third to a half of those affected. Contemporary dissatisfaction estimates appear closer to 7–14% than the historical “one-in-five” paradigm, with persistent pain and stiffness the dominant drivers of residual dissatisfaction. Symptoms arise from interacting mechanical, fibrotic, infective, neuropathic, central and psychosocial mechanisms. Six practical phenotypes are proposed—pain-dominant with preserved motion, stiffness-dominant, combined stiff-and-painful, neuropathic-dominant, centrally sensitized, and arthrofibrosis with true mechanical block—and diagnosis, prevention and management are organized around them, spanning risk stratification, surgical technique, manipulation under anesthesia (mean gains ~30–47°, ~6% failure), arthrolysis, revision and multidisciplinary pain care. Conclusions: Chronic pain and stiffness are the quiet arithmetic of arthroplasty success—rare on the survivorship curve, common in the clinic. Matching treatment to phenotype and reserving the operating theater for a knee with a mechanical fault to fix rather than a nervous system to calm, offers the clearest path from a technically successful operation to a genuinely successful recovery. Full article

Objectives: Osteoarthritis (OA) of the medial compartment in varus knee is a common degenerative condition. High tibial osteotomy (HTO) has been recognized as a primary joint-sparing procedure. The aim of this systematic review was to investigate functional and radiological outcomes, complications, and the progression of knee OA in patients undergoing medial opening wedge HTO. Methods: A total of 18 studies were included. Patients’ demographics, Knee Injury and Osteoarthritis Outcome Score (KOOS), number and types of complications, conversion in arthroplasty surgery rate, survival rate, and radiological evaluation were recorded. Results: A total of 2683 patients were evaluated. The frequency-weighted mean follow-up was 168.6 ± 54.6 months. The mean preoperative KOOS score was 46.5 ± 19, while postoperatively the mean score was 66.4 ± 22.9 (p < 0.001). The pre- and postoperative mTFA angle was −5.7° ± 2.8°, and 1.4° ± 2.4°, respectively; with a statistically significant improvement (p = 0.002). A total of 12.5% of patients had a conversion to a total knee arthroplasty and 1.5% had a conversion to unicompartmental knee arthroplasty, while 1.3% of the patients had a revision surgery unrelated to arthroplasty. The survival rate after 10 years was 86.3%. The nonunion rate was 1.3% and the infection rate was 0.9%. Conclusions: Patients who underwent medial opening wedge HTO achieved a significant correction of mTFA associated with an improvement in functional outcomes. An 86% survivorship rate at 10 years was observed, while a 14% conversion rate to knee arthroplasty for OA progression was reported after a mean follow-up of 14 years. Full article

Background/Objectives: Patellofemoral joint (PFJ) replacement is a bone-preserving option for isolated patellofemoral osteoarthritis; however, reported survivorship and failure patterns remain variable. This study evaluated implant survivorship, functional outcomes, reoperations, and failure mechanisms following PFJ replacement using standard second-generation implant systems, with or without patellar resurfacing. Methods: We retrospectively reviewed a consecutive cohort of 39 patients (48 knees) who underwent PFJ replacement for isolated patellofemoral osteoarthritis between 2011 and 2021. Median age at surgery was 59 years, and median body mass index (BMI) was 31 kg/m². Median follow-up for clinical and revision surveillance was 9 years (IQR 8–10). Functional outcomes were assessed using the Oxford Knee Score (OKS) and SF-12 Physical and Mental Component Scores (PCS and MCS). Implant survivorship was analyzed using Kaplan–Meier methodology, with conversion to total knee arthroplasty (TKA) as the endpoint. Statistical analyses were primarily descriptive and exploratory because only five TKA revisions occurred. Results: Median OKS improved from 19 (IQR 16–24) preoperatively to 36 (IQR 24–42) at the latest follow-up, with a median paired improvement of 17 points. SF-12 PCS improved from 25 to 47, and SF-12 MCS from 36 to 55. Eight knees (16.7%) underwent non-revision reoperation, and five knees (10.4%) underwent conversion to TKA. All TKA revisions were performed for the progression of tibiofemoral osteoarthritis. Kaplan–Meier survivorship free from TKA revision was 89.6% at 9 years (95% CI 76.8–95.5). No clear difference in TKA-free survivorship was detected between resurfaced and non-resurfaced knees. Conclusions: PFJ replacement demonstrated substantial functional improvement and mid- to long-term survivorship comparable to published registry ranges in a selected cohort with isolated patellofemoral osteoarthritis. TKA revision was uncommon and was attributable to the progression of tibiofemoral osteoarthritis. Because of the retrospective design, small cohort size, bilateral cases, and limited number of revision events, subgroup and risk-factor analyses should be interpreted as exploratory. Full article

Background/Objectives: This investigation was performed because corticosteroid injections are commonly used for symptomatic relief in patients with meniscal deficiency, yet their effect on graft survivorship and postoperative outcomes following meniscal allograft transplantation (MAT) remains poorly understood, with limited literature specifically addressing this topic. The aim of this study is to evaluate whether preoperative intra-articular corticosteroid injections (ICS) are associated with reoperation after MAT. Secondary aims included comparing reoperation-free survival, patient-reported outcome measures (PROMs), and patient acceptable symptom state (PASS) achievement. Methods: A retrospective review of 130 adults undergoing meniscal allograft transplantation (MAT) between 2011 and 2023 was performed. Patients with documented corticosteroid injection (CSI) status and ≥2 years of follow-up were included. Exclusion criteria included prior meniscal allograft transplantation, receipt of non-corticosteroid injections (e.g., hyaluronic acid or platelet-rich plasma), concomitant osteotomy procedures, multi-ligament knee reconstruction or inadequate follow-up. Propensity score matching (2:1 no steroid: steroid) based on age, sex, body mass index, fixation technique, operative compartment, and concomitant procedures yielded 54 matched patients (35 no steroid, 19 steroid). The primary outcome was ipsilateral knee reoperation, categorized as major reoperation (revision MAT, anterior cruciate ligament reconstruction, osteochondral allograft transplantation, conversion to total knee arthroplasty, meniscectomy and meniscus repair). Minor reoperations included irrigation and debridement, lysis of adhesions or manipulation under anesthesia, hardware removal, chondroplasty, and synovectomy. Reoperation-free survival was assessed using Kaplan–Meier analysis. PROMs and PASS were compared using adjusted regression models. Statistical significance was set at p < 0.05. Results: Baseline characteristics and follow-up were comparable between groups (7.6 ± 3.5 vs. 6.6 ± 3.2 years; p = 0.30). Overall reoperation occurred in 37.1% of patients in the no-steroid group and 31.6% in the steroid group (p = 0.771). Major reoperation rates were similar (17.1% vs. 15.8%; p = 1.000. There was no significant difference in minor reoperations between groups (20.0% vs. 10.5%; p = 0.468). Kaplan–Meier analysis demonstrated no difference in reoperation-free survival (p = 0.903), with comparable survival at the 1-, 2-, and 5-year time points. No individual subtypes differed significantly between groups. PROMs and PASS achievement were also similar, with no statistically significant differences observed. Conclusions: Preoperative corticosteroid injection was not associated with increased reoperation risk, inferior reoperation-free survival, or worse patient-reported outcomes following meniscal allograft transplantation. However, given the study’s limited power, lack of detailed injection characteristics, and the use of a heterogeneous complication outcome, these findings should be interpreted cautiously, as further investigation is warranted. Full article

Background: Periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) is a serious complication associated with substantial morbidity and healthcare costs. Although two-stage revision arthroplasty is widely accepted as a standard treatment, debridement, antibiotics, and implant retention (DAIR) is frequently attempted as a less invasive initial strategy. However, the impact of failed DAIR on the outcomes of subsequent two-stage revision remains controversial. Methods: This retrospective cohort study included patients who underwent two-stage revision arthroplasty for PJI following TKA at a single institution between 2005 and 2019, involving 84 knees at an average follow-up of 5.1 ± 3.3 years. Outcomes were compared between patients with a history of failed DAIR (F-DAIR group, n = 23) and those who underwent direct two-stage revision without prior procedures (DTSR group, n = 61). Treatment failure rates and associated risk factors were analyzed. Results: There was no significant difference in treatment failure rates between the F-DAIR and DTSR groups (4.3% vs. 9.8%, respectively; p = 0.668). Cox regression suggested that PJI type (acute vs. chronic) and diabetes mellitus were associated with treatment failure. Conclusions: In this retrospective cohort, prior failed DAIR was not associated with a statistically significant reduction in the success of subsequent two-stage revision arthroplasty. These findings may support consideration of DAIR as an initial treatment option in carefully selected patients; however, cautious interpretation is warranted because of the retrospective design, limited sample size, baseline imbalance, and small number of failure events. Therefore, the findings should be considered hypothesis-generating rather than definitive comparative evidence. Full article

Objectives: Periprosthetic joint infections represent a serious complication following joint arthroplasty, often leading to significant morbidity, with an economic and social impact on the health system. Timely diagnosis of periprosthetic joint infections remains a major challenge. Our study aimed to investigate the diagnostic value and accuracy of several markers, including the neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, and C-reactive protein-to-serum-hemoglobin ratio in revision surgery for periprosthetic joint infections. Methods: A total of 251 revision arthroplasty cases, including 137 cases of periprosthetic joint infections and 114 cases of aseptic revision arthroplasty, were included from the time span January 2016 to May 2025. The diagnostic value and accuracy of the C-reactive protein-to-hemoglobin ratio, neutrophil-to-lymphocyte ratio, and monocyte-to-lymphocyte ratio were evaluated using sensitivity, specificity, and receiver operating characteristic (ROC) analysis with area under the curve analysis. Results: The highest diagnostic performance was obtained by the C-reactive protein-to-hemoglobin ratio, yielding an AUC of 0.859 (SE = 0.0263, 95% CI: 0.809–0.899). This ratio also demonstrated a strong discriminative capacity, with a threshold of >0.0667, sensitivity of 80.45%, and specificity of 85.96%. For the neutrophil-to-lymphocyte count ratio and monocyte-to-lymphocyte count ratio, we obtained an AUC of 0.615 (95% CI: 0.551–0.676) and 0.620 (95% CI: 0.556–0.680), respectively, demonstrating lower sensitivity and specificity than the C-reactive protein-to-hemoglobin ratio. Conclusions: The C-reactive protein-to-hemoglobin ratio demonstrated better diagnostic strength in detecting periprosthetic joint infections, with superior sensitivity and specificity compared to the neutrophil-to-lymphocyte count ratio and monocyte-to-lymphocyte count ratio. Our findings offer new insights into the accurate and early diagnosis of periprosthetic joint infections in cases requiring revision surgery and suggest incorporating these new biomarkers and ratios into the diagnostic algorithm. Future large-scale studies are further needed to validate these results and facilitate their clinical use. Full article

Background/Objectives: Frailty has emerged as a relevant marker of biological vulnerability in patients undergoing complex orthopedic procedures, yet its specific prognostic value in revision total hip and knee arthroplasty remains incompletely synthesized. This systematic review evaluated whether validated preoperative frailty assessment tools are associated with adverse postoperative outcomes after revision total joint arthroplasty and whether available studies allow comparison of prediction performance across instruments. Methods: A systematic search of PubMed/MEDLINE, Embase, the Cochrane Library, Web of Science, Scopus, citation lists, and selected gray-literature sources was performed from inception through January 2026. Gray-literature records and conference abstracts were used only for citation tracking; the synthesis included only full-length peer-reviewed original research articles involving adult patients undergoing revision total hip arthroplasty, revision total knee arthroplasty, or both, with quantitative outcomes according to a validated frailty measure. Because of heterogeneity in frailty tools, outcome definitions, revision indications, and adjustment strategies, findings were synthesized narratively and certainty was assessed by outcome domain. Results: Eleven full-length studies were included, with cohorts ranging from 117 patients to 576,920 admissions, and most were retrospective database analyses. Higher frailty burden was consistently associated with worse short-term outcomes, including complications, prolonged hospital stay, readmission, non-home discharge, resource use, and mortality-related risk stratification. Representative findings included 30-day readmission of 23.8% versus 9.9%, surgical complications of 28.6% versus 7.8%, and odds ratios of up to 10.79 for complications across escalating frailty strata. Prediction studies suggested stronger discrimination for revision-specific or broader models, such as CARDE-B, RAI-rev, and machine-learning approaches, than for simpler generic frailty indices. Conclusions: Frailty is a consistent preoperative marker of elevated short-term perioperative risk after revision arthroplasty. The available evidence supports incorporating frailty assessment into preoperative risk stratification and counseling, but it remains insufficient to establish one universally preferred tool or to prove that frailty screening alone improves outcomes without targeted intervention. Full article

Background/Objectives: Despite its beneficial effect on the healing of bone fractures and in the treatment of osteoporosis, there is still a lack of evidence on the impact of clinical outcomes after a total joint arthroplasty (TJA). This review aims to establish the role of vitamin D in clinical outcomes after a total knee arthroplasty (TKA). Methods: In this review, PubMed, Scopus and Web of Science databases were cross-checked by two reviewers independently. The inclusion criteria were original human studies published in English from 2014 to 2024. For identification-relevant studies, the search terms used were as follows: “Vitamin D” and “total knee arthroplasty” or “total knee replacement” or “total joint arthroplasty” or “total joint replacement”. Case reports, letters and expert consensuses were excluded from the analysis. Finally, 19 studies were included in this review. Results: A literature review shows that vitamin D may have an impact on patients treated for osteoarthritis (OA) of the knee with a significant prevalence of hypovitaminosis in orthopedic patients. The influence was observed for periprosthetic joint infections: PJI patients have significantly lower vitamin D levels than primary ones. Also, a greater incidence of revision knee surgery due to PJIs in the deficient group compared to the non-deficient group at a one-year follow-up was found, of up to a 2-fold increase. This affects the clinical outcome with a lower Knee Society Score (KSS) functional score in the vitamin D-deficient group. Conclusions: The current data suggest that the vitamin D metabolism pathway and its implications in orthopedic patients, especially those treated with TKA surgery, may be a significant factor that improves clinical and functional outcomes. A possible relation between a low preoperative concentration of vitamin D and its impact on the outcomes, such as the length of the hospital stay, implant survival, and risk of complications, is needed to support these findings in multicenter, prospective studies and randomized controlled trials. Full article

Background: The success rates of treating chronic periprosthetic joint infection (PJI) have plateaued in the last two decades utilizing exchange protocols combined with extended parenteral antimicrobials. At the same time, extended systemic antimicrobials carry well-recognized adverse effects, including organ toxicity, metabolic derangements, and disruption of host–microbiome balance, which may themselves impair host inflammatory responses and tissue healing. The defined challenge is to intensify local site eradication while minimizing systemic antimicrobial exposure and its associated host harms. This study introduces a tactical treatment shift focusing on local microbial biocidal treatment, that we aptly name “antimicrobial brachytherapy” protocol (ABP). Methods: A consecutive case series of 25 patients with chronic PJI in total knee arthroplasty (TKA) were treated with the ABP from 2019 to 2023. In brief, the protocol includes: (1) local multimodal antimicrobial therapy applied during debridement to reach and extinguish microbial reserves, (2) eliminating parenteral antimicrobials and limiting oral antimicrobials to 3 weeks, and (3) employing variable explantation times (longer when needed) via a 1.5 exchange technique allowing individualized host and limb rejuvenation. Patients were graded according to McPherson host scoring. Musculoskeletal Infection Society (MSIS) tier levels were used to rate success. All patients had a minimum two-year follow-up. Results: Eighty percent of the patients were significantly compromised, consisting of B and C hosts having 2 and 3 limb scores. Outcomes using the MSIS tier rating show 16/25 (64%) tier 1 success (infection-free without antimicrobial suppression). In these 16 patients, three were still using their 1.5 implant at a mean 4.2 years (2–5.5 years). There were two (8%) tier 3C outcomes (aseptic revision at <1 year), and six (25%) tier 3E failures (amputation, resection arthroplasty or arthrodesis) with four amputations for continued infection, and two who underwent a repeat 1.5 exchange for recurrent infection. Of the four patients amputated, three had fungal microbes identified in post-resection aspirations. Lastly, there was one (4.15%) tier 4a outcome (mortality at <1 year). Conclusions: The ABP concept is a tactical shift focusing antimicrobial therapy within the zone of infection, avoiding long course systemic antimicrobials, and allowing variable explantation time for host and limb rejuvenation. Success was comparable to published MSIS tier 1 outcomes using traditional two-stage exchange protocols with extended parenteral antimicrobials. Given the small sample size and absence of a comparator, the results should be regarded as hypothesis-generating, and require validation in larger, randomized, controlled studies. Full article

Background: Rapid and accurate preoperative diagnosis of periprosthetic joint infection (PJI) in patients undergoing revision arthroplasty remains challenging. Intraoperative differentiation between PJI and aseptic failure is limited by the lack of rapid and reliable diagnostic tools. Flow cytometric bacterial cell count of synovial fluid may represent a promising adjunct in this setting. This study explores the feasibility of using flow cytometric bacterial count of synovial fluid in the detection of PJI in patients during revision arthroplasty. Methods: In this exploratory pilot study, 93 patients provided informed consent. After exclusion of dry taps (n = 33), synovial fluid samples were collected intraoperatively from 60 patients undergoing revision total hip (THA) or total knee arthroplasty (TKA) at three hospitals in the Netherlands. Sixty samples were analyzed using the Sysmex UF-4000 to quantify flow cytometrically bacterial cells. Infection status was retrospectively determined according to the criteria of the European Bone and Joint Infection Society (EBJIS). Group differences were assessed using non-parametric analyses. Results: After exclusions due to dry taps and technical issues, samples of 43 patients could be analyzed. Of these patients, 16 had a confirmed PJI. Bacterial counts were significantly higher in patients with PJI compared with aseptic failure (median 1029 [IQR 287–4089] vs. 251 [IQR 92–433], p < 0.01). Conclusions: Flow cytometric synovial fluid analysis using the Sysmex UF-4000 demonstrated the ability to differentiate between patients with a PJI and with aseptic failure based on bacterial counts. However, this study was underpowered for diagnostic accuracy claims, and the feasibility of using flow cytometric bacterial count over established parameters such as total leukocyte and PMN% remains unclear at this stage. Full article

The available literature provides limited and inadequate data regarding the association between intraoperative knee kinematics, long-term clinical outcomes and survivorship after total knee arthroplasty (TKA). This study aimed to examine the potential relationship between specific intraoperative kinematics laxity assessment, acquired with a computer navigation system, and the long-term clinical outcomes and survivorship in patients undergoing TKA. This study consists of a retrospective cohort analysis of consecutive TKA procedures, in which a surgical navigation system was utilized to intra-operatively assess bone resections, implant positioning and gap balancing. The intraoperative kinematic parameters included varus-valgus laxity at 0° (VV 0) and 30° of flexion (VV 30), anterior–posterior displacement at 90° of flexion (AP 90), and passive range of motion (ROM). Different prosthesis designs were used, with a predominance of the posterior stabilized (PS)-type implant. The Knee Injury and Osteo-arthritis Outcome Score (KOOS) was used to investigate patients’ clinical and functional status. Survival was analyzed with the Kaplan–Meier method. Between-group comparisons were performed using the Mann–Whitney U test. A univariate logistic regression analysis was conducted to identify factors associated with clinical failure. Of 165 eligible patients, 120 were included in the final analysis, with a mean follow-up of 7.7 ± 2.8 years. Revision surgery was required in seven cases, representing surgical failure and an overall survival rate of 94.2%, with survival probabilities of 98.8%, 97.4%, and 93.6% at 6, 8, and 10 years, respectively. Clinical failure (KOOS < 70 in three domains) occurred in 23 patients. No intra-operative surgical parameters, including Hip-Knee-Ankle angle, Preoperative KL grade, prostheses design, VV 0, VV 30, AP 90 and ROM, or demographic variables, were found to be statistically correlated with clinical failure at follow-up. Although, in this navigated TKA cohort, survivorship was acceptable and consistent with previously reported benchmarks, it was not possible to reliably predict survival probability based solely on the intra-operative laxity parameters measured. Nevertheless, the use of surgical navigation can help surgeons accurately assess bone resections and the balance of prosthetic components. Full article

(1) Background: Megaprosthetic reconstruction of the knee is frequently required in limb salvage surgery for oncologic indications and in complex revision arthroplasty. The Modular Universal Tumor and Revision System (MUTARS) Total Knee prosthesis is widely used in these situations. The aim of this study was to evaluate revision-free implant survival following MUTARS Total Knee implantation and to compare outcomes between primary implantation and use as a conversion procedure after failure of a previous knee prosthesis. (2) Methods: A retrospective cohort study was performed including 36 patients who underwent MUTARS Total Knee implantation at a single institution. Patients were stratified into primary implantation (n = 24) and conversion after failed prosthesis (n = 12). The primary endpoint was time to first revision. (3) Results: Overall revision-free survival was 51.6% at 2 years and 29.3% at 5 years. No significant difference in revision-free survival was observed between primary implantation and conversion procedures (log-rank p = 0.67). When mechanical failure (Henderson type III) was considered as the sole endpoint, implant survival was substantially higher, with 88.3% survival at 2 years and 57.2% at 5 years. Infection-related implant survival was 72.0% at both 2 and 5 years. Secondary amputation was required in 7 of 36 patients (19.4%), with a higher proportion observed in the primary implantation group (25.0% vs. 8.3%). Most amputations occurred within the early postoperative period. (4) Conclusions: MUTARS Total Knee implantation is associated with a substantial revision burden; however, conversion after failed prosthesis did not result in inferior revision-free survival compared with primary implantation. Endpoint-specific analyses demonstrate that biological complications, particularly infection, represent the dominant drivers of early failure. Full article

Background: Medial-compartment knee osteoarthritis (KOA) carries substantial disability and long-term cost. High tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) are key joint-preserving or joint-replacing options for selected patients, but their comparative economic ranking remains uncertain. Methods: This critical narrative review synthesized comparative economic evidence on HTO versus UKA for isolated medial-compartment KOA. PubMed and Web of Science were searched as primary sources for English-language studies published from 1 January 2000 to 15 January 2026, while Google Scholar and citation tracking were used supplementarily to identify potentially missed records. Eligible studies were direct economic evaluations or comparative cost/resource studies with clear decision relevance to the HTO–UKA choice. Burden and cost-of-illness studies were used for contextual framing only and were not included in the core comparative synthesis. Results: The direct evidence base was small and methodologically heterogeneous and was dominated by decision-analytic models that differed in perspective, time horizon, utility metric, and assumptions regarding reoperation, revision, and conversion to total knee arthroplasty (TKA). These structural differences largely explain why a U.S. lifetime societal model favored HTO, a UK age-stratified 10-year model produced age-dependent findings, and a recent Canadian public-payer model favored UKA. Observational studies suggest that UKA episode costs can fall substantially in outpatient or ambulatory pathways, whereas HTO costs may rise when reoperations and technique-specific resource use are explicitly captured. Conclusions: Current evidence does not support a context-free economic ranking of HTO and UKA. Because the available studies are heterogeneous and incremental utility differences are often small, the findings should be interpreted cautiously and as scenario-dependent rather than definitive. Future comparative analyses should use contemporary pathway data, transparent and standardized costing, and explicit downstream event definitions for both procedures. Full article

Patellar maltracking is among the most common causes of anterior knee pain after total knee arthroplasty (TKA), underscoring the need for accurate prevention and treatment. Therefore, the purpose of this narrative review is to provide a comprehensive overview of current evidence on post-TKA tracking, focusing on component alignment, preoperative patient assessment, and revision treatment options. A PubMed database search was performed, leveraging the literature from the last 20 years, and the results were qualitatively synthesized. According to current studies, several precautions should be taken to prevent patellofemoral stress and, consequently, patellar maltracking, such as avoiding internal rotation, valgus alignment, and excessive flexion of the femoral component and internal rotation of the tibial component. Regarding alignment strategies, kinematic alignment appears to offer potential benefits over mechanical alignment in certain functional outcomes and patient satisfaction scores. However, these differences should be interpreted cautiously as they may not always exceed the minimal clinically important difference. Furthermore, recent evidence indicates that quadriceps biomechanics influence TKA outcomes, potentially suggesting that conventional surgical approaches may need to be individualized, though these preliminary findings require prospective validation. Currently, robotic-assisted surgery represents a developmental direction for patient-tailored interventions and offers great promise for better prosthesis customization to the individual patient. Integration of imaging data with dynamic soft-tissue assessment enables more predictable reconstruction of joint kinematics. Regarding surgical treatment, the selection of specific methods requires a prior clinical and radiographic assessment. Indications range from patellar maltracking direction and component malrotation to patient preferences and rehabilitation potential. Ultimately, the future of TKA relies on personalized interventions to prevent complications and improve patient outcomes. This evolution is driven by the shift from mechanical alignment to kinematic alignment, alongside quadriceps tendon assessment and intraoperative robotic-assisted measurement, all aimed at optimizing the accuracy of implant positioning. Full article

Background: Late-onset anaerobic prosthetic joint infection (PJI) is uncommon but may indicate underlying, previously asymptomatic colorectal malignancy. While the association between Streptococcus bovis group (SBG) bacteremia and colorectal cancer is well established, links between anaerobic PJIs and colorectal neoplasia are rarely reported. Anaerobic organisms originating from the gastrointestinal tract may translocate via the hematogenous route, and their presence in PJI should prompt clinicians to consider occult colorectal pathology. Methods: All periprosthetic arthroplasty infection cases between 2015 and 2025 were reviewed. Clinical records, diagnostic findings, microbiological data, and treatment outcomes were analyzed. Results: Three female patients (mean age 76.3 years) presented with late-onset PJI occurring at least five years after primary total knee arthroplasty. Causative organisms included Bacteroides fragilis, Morganella morganii, and Klebsiella pneumoniae. All patients underwent two single-stage revision surgeries and one debridement, antibiotics and implant retention (DAIR) procedure. Cross-sectional computed tomography imaging of the abdomen and pelvis (CT-AP) performed to evaluate hematogenous sources of infection consistently revealed previously undiagnosed colorectal malignancy. One patient had additional metastatic disease. Postoperative complications included one case of pulmonary embolism; no other major complications were observed. Conclusions: Anaerobic PJIs are rare, and their association with colorectal malignancy is not well established. These cases highlight the importance of evaluating potential gastrointestinal sources, including occult colorectal cancer, in patients presenting with late-onset anaerobic PJI. Full article