Knee Surgery and Related Research最新文献

Background: An overhang of the tibial component can cause irritation of the surrounding soft tissues, whereas an underhang is associated with risks of tibial bone resorption. It is not well known whether the tapering angle of currently available blocks at medial, lateral, anterior, and posterior sides matches the actual shape of the proximal tibia. The purpose of this study was to analyze the bony contour of the proximal tibia and measure the tapering angle to examine whether the angle of currently available metal augmentation blocks matches the actual tibia.

Methods: Computed tomography of the lower extremities was performed on 100 consecutive knees, and three-dimensional images of the tibia were reconstructed. The primary resection level was determined on the basis of a plane 10 mm below the center of the lateral tibial plateau. The assumed levels were set to 5, 10, 15, and 20 mm below the primary resection level. All points that were 5, 10, 15, or 20 mm below were projected onto the primary resection surface, and the reduction value from the primary level to each level was measured. The tapering angle was calculated on the basis of the reduction value from the primary level to each resection surface at eight areas and compared with the angle of currently available metal augmentation acquired from the company. The distances of mismatch between the metal augmentation and the bone surface were calculated.

Results: The tapering angle on the medial and lateral sides increased with the more distal resection level, which was up to 30° at the 20 mm level. The tapering angle on the posterior side also increased with the more distal resection level, which was approximately 40° at the 20 mm level. The tapering angle of the current implant was smaller than that of the original tibial morphology. The distances of mismatch varied between implants in which the maximum distance was up to 11.3 mm in the 15 mm augmentation.

Conclusions: The design of current metal augmentation differs from the morphology of the proximal tibia. Surgeons should pay attention to the size mismatch between the femoral and tibial components during revision total knee arthroplasty (TKA).

Introduction: Population-based differences in knee alignment patterns may impact osteoarthritis (OA) progression. This study compares lower extremity alignment in knee OA between Middle Eastern (UAE) and East Asian (South Korean) populations using artificial intelligence (AI)-assisted analysis.

Methods: A retrospective review included patients with knee symptoms from South Korea (2009-2019) and the United Arab Emirates (UAE) (2015-2024). Exclusion criteria comprised prior knee surgeries, significant bony attrition, and low-quality radiographs. Propensity score matching controlled for age and sex differences between populations. Alignment parameters (hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), and joint line convergence angle (JLCA)) and OA severity (Kellgren-Lawrence (KL) grade) were measured using artificial intelligence (AI) software, along with the analysis of coronal plane alignment of the knee (CPAK) classification. Subanalyses by sex and age group (under 40, 40-60, and over 60 years) were also conducted.

Results: A total of 1098 UAE and 7138 South Korean patients (2196 and 14,276 knees, respectively) were evaluated in this study. Post-matching (1:2), body mass index was significantly higher in UAE patients (p < 0.001). CPAK type 1 was predominant in UAE male patients (42.4%), whereas type 2 was more common in South Korean male patients (30.6%). Female patients in both populations predominantly exhibited CPAK type 2 (UAE 30.6%; South Korea 35.3%). UAE patients showed a lower MPTA with increasing age, indicating a trend toward more varus alignment in older individuals.

Conclusions: A propensity score-matched analysis revealed significant alignment differences between Middle Eastern and East Asian populations, underscoring the importance of population-specific considerations in OA management.

Background: McMurray's test is a useful physical examination in determining meniscus tears, yet its sensitivity is only 38-62%. Furthermore, the relationship between degenerative meniscus tears (DMT) and mechanical symptoms during McMurray's test is not well defined. Perimeniscal synovitis occurs in osteoarthritic (OA) knees, inducing localized symptoms such as posterior knee pain in medial meniscus posterior horn DMTs. This study aimed to determine the relationship between McMurray's test with medial meniscus DMT and perimeniscal synovitis in patients with knee OA.

Methods: We retrospectively analyzed 60 patients who underwent medial unicompartmental knee arthroplasty (UKA) with positive (n = 20) and negative (n = 40) preoperative McMurray's tests. Preoperative magnetic resonance imaging (MRI), intraoperative gross morphology, and histological analysis of meniscus and synovium were evaluated to determine meniscal tears and perimeniscal synovitis. Univariate and multivariate regression analyses were done to determine the effects of meniscus tears and synovitis on McMurray's test results.

Results: Gross morphology of the medial meniscus (MM) showed 14 out of 20 torn menisci in the McMurray's (+) group compared with 22 out of 40 in the (-) group, with no difference in meniscus tear severity among groups. The (+) group showed higher values of synovial thickness (p < 0.001) and area (p < 0.001) compared with the (-) group on magnetic resonance imaging (MRI). Histological analysis showed higher synovitis (p < 0.001) scores and expression of inflammatory markers [interleukin (IL)-1β (p < 0.001), IL-6 (p = 0.007), nerve growth factor (NGF) (p = 0.003), inducible nitric oxide synthase (iNOS) (p < 0.001)] in the perimeniscal synovium of (+) group compared with the (-) group. Multivariable logistic analysis revealed that larger synovial area [odds ratio (OR) = 1.106, p = 0.008] and a higher histologic synovitis score (OR = 2.595, p = 0.011) were independently significant predictive factors for a positive McMurray's test.

Conclusions: McMurray's test may be influenced by perimeniscal synovitis in DMT patients. The clinical implications of our results may influence not only the interpretation of McMurray's test but also the target tissue in treating mechanical symptoms related to meniscus tears.

Level of evidence: Level II.

Purpose: Kinematic alignment (KA) in total knee arthroplasty (TKA) aims to restore the patient's knee to the prearthritic state. The purpose of this study was to investigate the accuracy of using an implant-agnostic, imageless, accelerometer-based navigation system to perform KA TKA on the basis of caliper verification and quantification of the flexion and extension gaps.

Materials and methods: Seven cadaveric lower extremities underwent primary TKA utilizing a kinematic alignment workflow with the imageless navigation system. Accuracy of the technique was confirmed through caliper verification of bone cuts.

Results: All cuts were within 1 mm of anticipated measurements, except for the lateral tibial fragment, which averaged 1 mm (standard deviation [SD] 0.9 mm) thicker than anticipated. In extension, medial and lateral gaps were symmetric and averaged within 0.6 mm of expectation. In flexion, the medial gap averaged within 0.5 mm of expectation, while the lateral gap averaged 2.6 mm larger than the symmetric expectation, consistently producing a trapezoidal space.

Conclusions: The implementation of an accelerometer-based navigation system in KA TKA allows for highly accurate results, which was confirmed with caliper verification. This workflow produced a symmetric extension gap and a trapezoidal flexion gap with an average increased lateral flexion gap of 2.6 mm compared with the medial side.

Background: Patellofemoral pain syndrome (PFPS) is one of the most common conditions affecting the knee joint, yet its pathomechanics remain unclear. The aim of this study was to investigate changes in muscle activation and gait patterns and to analyze the relationship between muscle activation and kinetic gait patterns in patients with PFPS.

Methods: This study included 31 patients with PFPS and 28 healthy volunteers without any symptoms. The sagittal plane motion of the knee joint, representing primary movement of the knee joint, was evaluated to identify changes in gait patterns. Electromyography (EMG) was used to measure muscle activation of vastus medialis (VM), vastus lateralis (VL), semitendinosus (ST), and gastrocnemius (GCM) muscles during gait analysis. Biomechanical features were analyzed during the three phases of the gait cycle; weight acceptance (WA), single limb support (SLS), and swing limb advancement (SLA) (0 ~ 12%, 13 ~ 50%, and 51 ~ 100% of the gait cycle, respectively).

Results: The average knee extension moment (KEM) during WA was lower in the patient group and no significant differences were observed in the knee flexion angle (KFA). With respect to muscle activation, the patient group showed significantly higher muscle activation of the ST muscle in all phases. As the absolute value of the moment increased, the activation of the VM, VL, and ST muscles increased more rapidly in the patient group, especially when KEM was under -1% body weight × height (Bw × Ht) or over 5% Bw × Ht.

Conclusions: Patients with PFPS exhibit elevated muscle activation, particularly in response to changes in the knee extension moment, which is likely a compensatory mechanism to manage knee joint loading during gait. These results highlight altered neuromuscular adaptations in PFPS, suggesting targeted therapies may help improve functional outcomes. Level of evidence III, cross-sectional study.

Background: There are no studies that compare the outcomes and complications of single-versus two-stage revision anterior cruciate ligament reconstruction (ACLR) after primary ACLR failure. This purpose of this study is to examine clinical and functional outcomes and complications associated with single and two-stage revision ACLR after primary ACLR failure.

Methods: All patients who underwent single or two-stage revision ACLR after primary ACLR failure between 2012 and 2021 with a minimum of a 2 year follow-up were included. Patients were excluded if they were not treated at our single academic institution, had inadequate follow-up, or had incomplete medical records. Revision intraoperative data, concomitant injuries, and complications were collected by chart review. Return to sport, numerical pain rating scale (NPRS) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Veteran Rands 12-item health survey (VR-12 scores) were collected.

Results: The final analysis included 176 patients. A total of 147 (83.5%) had a single-stage revision ACLR (87 male, 60 female), and 29 (16.5%) had a two-stage revision ACLR (13 male, 16 female). Two-stage revision ACLR was significantly associated with anterior knee pain [odds ratio (OR) 4.36; 95% confidence interval (CI) 1.5 to 12.65; P = 0.007] but with lower failure rates (OR 0.12, 95% CI 0.02 to 0.9; P = 0.04). On multivariate analysis, a two-stage revision ACLR reduced the risk of graft failure by 85% (OR 0.15; 95% CI 0.02 to 1.17; P = 0.07). Two-stage revision ACLR was significantly associated with a lower KOOS pain score (OR -11.7; 95% CI -22.35 to -1.04; P = 0.031), KOOS symptoms score (OR -17.11; 95% CI -28.85 to -5.36; P = 0.004), KOOS Activities of Daily Living (ADL) score (OR -11.15; 95% CI -21.71 to -0.59; P = 0.039) and Veterans RAND 12-Item Health Survey (VR-12) physical component score (OR -9.99; 95% CI -15.77 to -4.22; P = 0.001).

Conclusions: The clinical outcomes and subjective patient scores significantly differed between the single-stage and two-stage revision ACLR after primary ACLR failure. Patients with a two-stage revision ACLR had a significantly reduced risk of revision graft failure but higher rates of postoperative anterior knee pain, lower pain scores, and lesser knee functional scores than single-stage revision patients.

Study design: Retrospective cohort study; level of evidence, 3.

Introduction: Prosthetic joint infection (PJI) is one of the most common and detrimental complications of total knee replacement arthroplasty (TKA). Despite extensive efforts, including two-stage reimplantation, to eradicate PJI, it still recurs in a substantial number of patients. However, the risk factors of recurrence after two-stage reimplantation of the knee have not been established. In this study, it is hypothesized that there will be certain risk factors of recurrence after two-stage reimplantation for PJI of the knee.

Materials and methods: From March 2002 to December 2022, 65 knees that underwent two-stage reimplantation for PJIs in a single, tertiary hospital were retrospectively reviewed, and 44 patient-related, laboratory-related, and surgery-related factors, including body mass index, pathogen type, and the usage of transfusions, were selected as the potential risk factors for recurrence. Survival analysis using the Kaplan-Meier method and subsequent Cox proportional hazard regression were performed.

Results: Out of the 65 knees that underwent two-stage reimplantation, infection recurred in 15 knees (23.1%) in a median 11 (range 4-108) months. The Cox proportional hazards regression showed that infection of revision TKA, mixed pathogen-type infection, and higher serum erythrocyte sedimentation rate (ESR, mm/h) level increases the risk of recurrence (p-values < 0.001, 0.04, and 0.009; hazard ratios 40.29, 1.53, and 1.03, respectively).

Conclusions: A significant portion of PJI of the knees recurred after two-stage reimplantation. Revision TKA at the time of initial PJI, mixed pathogen-type infection, and higher serum ESR level were three significant risk factors of PJI recurrence. Surgeons should be more cautious in suspecting PJI relapse for these specific occasions.

Level of evidence: III, retrospective cohort study.

Background: Unplanned readmission, a measure of surgical quality, occurs after 4.8% of primary total knee arthroplasties (TKA). Although the prediction of individualized readmission risk may inform appropriate preoperative interventions, current predictive models, such as the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) surgical risk calculator (SRC), have limited utility. This study aims to compare the predictive accuracy of the SRC with a novel artificial neural network (ANN) algorithm for 30-day readmission after primary TKA, using the same set of clinical variables from a large national database.

Methods: Patients undergoing primary TKA between 2013 and 2020 were identified from the ACS-NSQIP database and randomly stratified into training and validation cohorts. The ANN was developed using data from the training cohort with fivefold cross-validation performed five times. ANN and SRC performance were subsequently evaluated in the distinct validation cohort, and predictive performance was compared on the basis of discrimination, calibration, accuracy, and clinical utility.

Results: The overall cohort consisted of 365,394 patients (training_N = 362,559; validation_N = 2835), with 11,392 (3.1%) readmitted within 30 days. While the ANN demonstrated good discrimination and calibration (area under the curve (AUC)_ANN = 0.72, slope = 1.32, intercept = -0.09) in the validation cohort, the SRC demonstrated poor discrimination (AUC_SRC = 0.55) and underestimated readmission risk (slope = -0.21, intercept = 0.04). Although both models possessed similar accuracy (Brier score: ANN = 0.03; SRC = 0.02), only the ANN demonstrated a higher net benefit than intervening in all or no patients on the decision curve analysis. The strongest predictors of readmission were body mass index (> 33.5 kg/m²), age (> 69 years), and male sex.

Conclusions: This study demonstrates the superior predictive ability and potential clinical utility of the ANN over the conventional SRC when constrained to the same variables. By identifying the most important predictors of readmission following TKA, our findings may assist in the development of novel clinical decision support tools, potentially improving preoperative counseling and postoperative monitoring practices in at-risk patients.

Background: Unicompartmental knee arthroplasty (UKA) is a surgical treatment for knee osteoarthritis associated with lower morbidity compared with total knee arthroplasty (TKA) in patients with isolated unicompartmental knee arthritis. As disparities have been noted broadly in arthroplasty care, it follows that such disparities might be present in the utilization of UKA relative to TKA. This study therefore examined racial/ethnic, socioeconomic, and payer status differences in utilization of UKA.

Methods: Patients who underwent UKA or TKA between 2016 and 2020 in the National Inpatient Sample were identified. Multivariable Poisson regression models adjusted for hospital geographic region and patient characteristics [age, sex, and Elixhauser Comorbidity Index (ECI)] were used to examine the effect of race/ethnicity, socioeconomic status, and payer status on incidence rate ratio of UKA relative to TKA.

Results: Of the 8472 UKA patients and 639,937 TKA patients identified between 2016 and 2020, 8027 (94.7%) UKA patients and 606,028 (94.7%) TKA patients met inclusion criteria. Patients who underwent UKA were significantly younger (63.5 ± 10.7 years) than patients who underwent TKA (66.8 ± 9.5 years; p < 0.001) and had significantly lower ECI scores (1.8 ± 1.5) than patients who underwent TKA (2.2 ± 1.6; p < 0.001). Black patients were less likely to undergo UKA relative to TKA compared with white patients [incidence rate ratio (IRR) 0.64, confidence interval (CI) 0.58-0.71, p < 0.001]. Compared with patients in income quartile 4, patients in income quartiles 1 and 2 underwent UKA at a lower relative rate (IRR 0.85, CI 0.79-0.90, p < 0.001 and IRR 0.87, CI 0.82-0.93, p < 0.001, respectively). Compared with patients with private insurance, patients with Medicare underwent UKA at a lower relative rate (IRR 0.83, CI 0.79-0.88, p < 0.001).

Conclusions: Black patients, lower-income patients, and Medicare-insured patients undergo UKA at a lower relative rate than white, higher-income, and privately insured patients, respectively. Further research may help elucidate reasons for these differences and identify targets for intervention.