Knee Surgery and Related Research最新文献

Background: Unicompartmental knee arthroplasty (UKA) is a common treatment for medial osteoarthritis, providing faster recovery and better joint kinematics than total knee arthroplasty (TKA). However, periprosthetic tibial plateau fractures (TPF) remain a significant complication. Undersized tibial components, especially size AA, increase TPF risk. This study aims to examine the biomechanical relation between tibial implant size and the risk of periprosthetic fractures.

Methods: A biomechanical study was conducted using 16 customized synthetic bone models to simulate the effects of tibial component sizing in UKA. Proximal tibial models with components of size A and size AA were subjected to axial loading, and the maximum load to failure and cycles to failure were measured for each size. Additionally, plastic axial deformation was calculated at the maximum load level of the weakest construct. Strain patterns were compared with clinically observed fracture lines reported in previous studies.

Results: Size AA had a significantly lower maximum load and cycles to failure compared with size A (1039 N ± 75 N and 9.336 ± 925 cycles versus 1140 N ± 83 N and 8.326 ± 759 cycles, p = 0.031). The strain patterns were consistent with those observed in clinical studies, showing a wedge-shaped distribution from the posteromedial to the anteromedial tibial plateau. Plastic deformation was less than 0.6 mm across all specimens, with no significant difference in axial displacement between the two groups (p = 0.64).

Conclusion: Undersizing the tibial component reduces load-bearing capacity of the tibial plateau and thereby increases the risk of periprosthetic fractures. Precise implant sizing by correct sagittal resection is essential to minimize the risk of fracture in UKA.

Experimental study: Type V.

Background: Bone irrigation is a crucial step in cemented total knee arthroplasty procedures to promote maximal cement penetration and interdigitation into the cancellous bone. However, it is not clear which type of bone irrigation achieves the best results. This study aimed to compare the efficacy of high-pressure pulsatile lavage versus manual rinsing in promoting bone cement penetration during total knee arthroplasty.

Methods: We conducted a single-center, prospective, randomized, controlled clinical trial in 100 patients undergoing primary total knee arthroplasty during 1 year. All patients were randomly allocated to either the pulsed lavage group or the non-pulsed lavage group. We assessed total cement penetration depth across all zones radiologically using anteroposterior and lateral radiographic views in postoperative X-rays taken on the first day after surgery and segmenting them into ten zones according to the Knee Society Scoring System (KSSS).

Results: The patient cohort included 100 individuals with an average age of 75 years (standard deviation [SD] 5.7); 73% were female. The mean total bone cement penetration values in both anteroposterior (AP) and lateral views were 10.77 mm (SD 5.95) and 4.85 mm (SD 3.33) for manual lavage, and 11.34 mm (SD 6.26) and 5.23 mm (SD 3.50) for pressurized lavage. We observed no significant differences between the two groups after adjusting for multiple variables.

Conclusions: High-pressure pulsatile lavage showed no significant differences in enhancing bone cement penetration compared with manual lavage as measured by the KSSS total knee arthroplasty bone cementation scale in X-rays taken on the first postoperative day. Level of Evidence Level I-Therapeutic randomized controlled trial. Trial registration Clinicaltrials.gov Register-NCT06032507.

Background: Although both unicompartmental knee arthroplasty (UKA) and medial open-wedge high tibial osteotomy (MOWHTO) are widely accepted surgical options for medial compartment osteoarthritis, there is limited evidence from long-term outcomes to confirm and refine their established indications. This study aimed to evaluate the long-term clinical and radiologic outcomes of UKA and MOWHTO when performed according to their established indications at a single institution, and to characterize the demographic and preoperative radiographic differences associated with surgical selection.

Methods: Patients who underwent UKA or MOWHTO for medial compartmental OA with a minimum 10-year follow-up were retrospectively reviewed. Preoperative characteristics, including age and the degree of medial OA using Kellgren-Lawrence grading, clinical outcomes, and radiologic parameters, including hip-knee-ankle angle (HKAA), medial proximal tibial angle (MPTA), and OA progression in the patellofemoral compartment, were compared. Survivorship based on the conversion to total knee arthroplasty was also evaluated.

Results: The current study included 79 UKAs and 140 MOWHTOs with a mean 13.2 ± 1.7 years follow-up. Preoperatively, the UKA group had significantly older age (P < 0.001) and more advanced degree of medial OA (P < 0.001) than the MOWHTO group. Postoperative clinical outcomes were not significantly different between the groups. Radiologically, the UKA group had significantly less varus alignment and larger MPTA than the MOWHTO group (all, P < 0.001). Although the proportion of OA progression in the patellofemoral joint was higher in the MOWHTO group than in the UKA group at the latest follow-up (P = 0.012), there was no significant difference in anterior knee pain. At the mean 13-year follow-up, survival rates were not significantly different between the UKA (96.2%) and MOWHTO (98.6%) groups.

Conclusions: Both UKA and MOWHTO demonstrated excellent long-term outcomes when performed under their established indications for medial compartment OA. Patients selected for UKA were older, had more advanced OA, less varus alignment, and a larger MPTA compared with those undergoing MOWHTO, consistent with published selection criteria. Radiographic progression of patellofemoral arthritis occurred more frequently after MOWHTO than after UKA, although this finding was not associated with clinical significance.

Background: The choice between simultaneous and staged bilateral total knee arthroplasty (TKA) remains controversial due to safety and resource considerations. This meta-analysis compared outcomes between the two approaches.

Methods: A total of 42 comparative studies published from 2001 to 2025 were included. A combined population of 567,915 patients was analyzed, with 225,181 undergoing simultaneous and 342,734 staged bilateral TKA. Random- or fixed-effects models were used to pool data across multiple clinical end points. Outcomes included in-hospital, first-year, and 1-2-year complications, mortality, functional outcomes, reoperations, persistent pain, and healthcare utilization metrics. Effect estimates were summarized using odds ratios (OR) for dichotomous outcomes and mean differences (MD) or standardized mean differences (SMD) for continuous outcomes, all with 95% confidence intervals (CI).

Results: Simultaneous TKA was associated with significantly higher odds of transfusion (OR 3.99; 95% CI 3.10-5.13; p < 0.001), first-year neurological complications (OR 1.48; 95% CI .128-1.71; p < 0.001), and first-year mortality (OR 2.43; 95% CI 2.02-2.92; p < 0.001). Pulmonary complications were significantly higher between 1 and 2 years postoperatively (OR 1.41; 95% CI 1.11-1.80; p = 0.005). However, joint infection (in-hospital, OR 0.59; 95% CI 0.40-0.89; p = 0.01), first-year periprosthetic fracture (OR 0.46; 95% CI 0.38-0.57; p < 0.001), and overall reoperation rates (OR 0.65; 95% CI 0.61-0.69; p < 0.001) were significantly lower in the simultaneous group. No significant differences were observed in functional scores, persistent pain, arthrofibrosis, knee instability, or extensor mechanism failure (p > 0.05). Simultaneous procedures were also associated with shorter operative times (MD -66.83 min; 95% CI -91.80 to -41.86; p < 0.001) and lower in-hospital costs (MD -$7062.67; 95% CI -13,927.78 to -197.56; p = 0.04).

Conclusions: Simultaneous bilateral TKA offers advantages in operative efficiency, cost reduction, and lower reoperation and fracture rates, but carries increased odds of neurological complications, transfusion, and early mortality. Careful patient selection and perioperative management are essential to balance these trade-offs when considering simultaneous procedures.

Background: Artificial intelligence (AI), including machine learning (ML) and deep learning (DL), is increasingly being integrated into total knee arthroplasty (TKA) to improve accuracy, efficiency, and personalized care. These technologies enable the analysis of large, complex datasets to support evidence-based clinical decision-making across all phases of the surgical process.

Main body: AI has demonstrated utility in multiple stages of TKA. In patient selection, ML algorithms can predict postoperative complications such as transfusion needs with high accuracy (AUC up to 0.842). For preoperative planning, DL techniques facilitate 3D anatomical reconstruction and implant size prediction, with some models achieving over 90% accuracy for exact component sizing, significantly outperforming traditional 2D templating. Intraoperatively, AI-assisted robotic systems and sensor technologies offer real-time feedback on alignment and soft tissue balancing. Postoperatively, AI-integrated wearable devices and mobile applications enable continuous monitoring and tailored rehabilitation; in some randomized trials, these tools have been associated with a statistically significant reduction in hospital readmission rates. Despite these advances, significant challenges remain, including algorithmic bias, a lack of model generalizability and explainability, and unresolved ethical and regulatory hurdles that present formidable barriers to widespread clinical implementation.

Conclusions: AI has the potential to significantly reshape TKA by enabling more precise, data-driven, and patient-centered care. However, its promise is contingent on overcoming critical limitations. Broader implementation requires robust multicenter validation to ensure model reliability, the development of explainable algorithms to build clinical trust, and a commitment to responsible innovation. With continued progress, AI can serve as a powerful complementary tool to augment surgical expertise and enhance patient outcomes in orthopedic surgery.

Purpose: To analyze the correlation and degree of agreement between the patellar heights measured at knee flexion of 0° and 30° before and after total knee arthroplasties (TKA) without patellar resurfacing.

Methods: One hundred primary TKAs with nonresurfaced patella were prospectively evaluated. We measured the Insall-Salvati ratio (ISR), modified ISR (mISR), Blackburne-Peel ratio (BPR), and Caton-Deschamps ratio (CDR) in weightbearing true lateral radiograph at knee flexion of 0° and 30°. The correlations between the patellar height measured at knee flexion of 0° and 30° were analyzed by Pearson correlation analysis. The degree of agreement between the patellar heights in knee flexion angles of 0° and 30° was analyzed using the limits of agreement (LoA) of Bland-Altman analysis; a difference of <  ± 0.2 between the measurements at knee flexion of 0° and 30° was deemed clinically acceptable.

Results: Very strong correlations existed between the pre- and postoperative ISR (r = 0.826 and 0.823, p < 0.001, respectively), and the preoperative mISR (r = 0.802, p < 0.001) measured between knee flexion angles of 0° and 30°. Strong correlation was observed in the other pre- and postoperative measurements. The range between upper and lower LoAs of the ISR measured at knee flexion of 0° and 30° was <  ± 0.20 preoperatively (-0.174 ~ 0.155) and postoperatively (-0.181 ~ 0.174), while the ranges for all other measurements did not lie within the clinically acceptable range.

Conclusions: The ISR measured at 0° or 30° of knee flexion during weightbearing can be interchanged reasonably before and after TKA. Although knee flexion of 30° is the standard, lateral radiograph of 0° flexion can be a reasonable alternative for evaluating patellar height using the ISR.

Level of evidence: Level II.

Background: Patellar instability is a multifactorial condition with varying severity, categorized into single-episode, recurrent, and habitual dislocations. This study aims to assess the association and the strength of association between clinical subtypes of patellofemoral instability (PFI) (single-episode, recurrent, and habitual patellar dislocation) and the frequency, severity, and cumulative presence of three key radiological risk factors: trochlear dysplasia, tibial tubercle-trochlear groove (TT-TG) distance, and the Caton-Deschamps (CD) ratio.

Methods: This was a retrospective observational study conducted from January 2018 to December 2024 on 106 patients reported in the outpatient department (OPD) with various type of patellar instability (124 knees; 39 knee SPD, 73 knee RPD, and 12 knee HPD). Three radiological parameters (trochlear dysplasia, tibial tuberosity-trochlear groove (TT-TG) distance with > 15 mm defined as high), and Caton-Deschamps (CD) ratio (> 1.2 indicating patella alta) were evaluated using magnetic resonance imaging (MRI). Chi-squared test and Cramér's V statistical methods were applied for analyzing the strength of association.

Results: The study identified prevalence of trochlear dysplasia in 63.7%, high TT-TG distance in 32.2%, and patella alta in 45.2% of knees with varying types of patellar instability. Trochlear dysplasia showed the strongest association, particularly with habitual dislocations (100%). Prevalence of high TT-TG progressively increased from single-episode (17.9%) to recurrent (32.9%) to habitual patella dislocation (75%). In contrast to trochlear dysplasia and high TT-TG distance, patella alta was found to have a weaker association in characterizing the patellar instability. Notable, correlation was observed with severity of patellar instability and the number of risk factors, with cases with habitual patella dislocation most frequently showing multiple contributing factors.

Conclusions: Our study found that patients with HPD, the most severe clinical form of patellar instability, had pronounced trochlear dysplasia, higher TT-TG distance, and a greater number of radiological risk factors, followed by RPD and finally SPD. Among the parameters, trochlear dysplasia and TT-TG distance showed stronger association with clinical types, while patella alta had a weaker correlation.

Soft-tissue balancing is essential for achieving optimal outcomes in total knee arthroplasty (TKA), significantly impacting postoperative joint function, patient satisfaction, and implant longevity. Despite advancements in surgical techniques, traditional methods for evaluating soft-tissue tension remain largely subjective, leading to inconsistent outcomes and patient dissatisfaction. Recent technological developments, particularly the integration of digital devices, have shown promise in transforming soft-tissue balancing from a subjective art into a reproducible science. This manuscript is a narrative review that systematically summarizes the historical and technological evolution of soft-tissue tension gauging methods in TKA, encompassing experiential methods, mechanical tensors, and contemporary digital sensors. We critically discuss the strengths, limitations, and available clinical evidence for each method. Furthermore, this review highlights the integration of robotic systems and provides insights into future translational strategies, emphasizing artificial-intelligence-driven personalized soft-tissue balancing as a promising therapeutic direction. This review further comprehensively discusses soft-tissue tension gauging methods in TKA, providing a clear understanding of their evolution from subjective assessments to objective digital technologies. This study provides a robust theoretical foundation for the clinical application of digital tensors and robotic technologies. Integrating these technologies with artificial intelligence can effectively transform soft-tissue balancing strategies, thereby enhancing surgical precision, patient satisfaction, and clinical outcomes in TKA.

Background: Meniscal allograft transplantation (MAT) and autologous chondrocyte implantation (ACI) are well-established procedures. However, evidence regarding the safety and efficacy of their combined application remains inconclusive. Thus, the present systematic review aimed to comprehensively evaluate the existing literature on clinical outcomes after combined MAT and ACI.

Methods: A comprehensive search of clinical studies reporting on clinical outcomes after combined MAT and ACI was performed across three databases in accordance with the review protocol. Key demographic data, surgical technique, knee-specific patient-reported outcome measures, failure rates, and reoperation rates were extracted from eligible studies and analyzed. Risk of bias was assessed using the Methodological Index for Non-Randomized Studies (MINORS).

Results: The search yielded 246 studies, 9 of which satisfied inclusion and exclusion criteria, comprising 155 patients undergoing combined MAT and ACI at an average age of 36.1 years. The mean follow-up duration was 5.3 years (2.0-12.9 years). Clinical outcome measures improved across all studies (with one exception in a single outcome measure); statistical significance was shown in six out of seven studies reporting significance analysis. International Knee Documentation Committee (IKDC) scores were reported by four studies, showing an average improvement of 22.0 points. Lysholm scores showed an average improvement of 20.0 points across five studies. Of five studies comparing combined procedures with isolated procedures, one comparative study and one literature comparison reported inferior outcomes after combined surgery, while one subgroup analysis and two literature comparisons found comparable outcomes. Failure rates ranged from 0.0% to 52.6%, with significant methodological heterogeneity. The mean reoperation rate was 35.0% across seven studies.

Conclusions: Combined MAT and ACI leads to meaningful improvements in clinical outcomes, with notable failure and reoperation rates. While some studies suggest outcomes may be comparable or inferior to isolated procedures, only one study directly assessed this. As such, definitive conclusions cannot be drawn. Combined MAT and ACI can be considered as a viable option in select patients, but realistic expectations must be ensured.