Open surgery for isolated posterolateral corner injury with hypermobile lateral meniscus was successful at a minimum follow up of 2years.

Target weight-bearing line after medial open-wedge high tibial osteotomy: A finite element analysis of meniscal and cartilage biomechanics.

Femoral Condylar Consumption Index (FCCI): A geometric MRI predictor of lateral meniscal lesion and re-tear.

Assessing the Responsiveness of Musculoskeletal Tissues to Protein Supplementation in vivo in Older Adults: an Exploratory Randomized Controlled Trial.

Distinct 3-Dimensional Anatomic Patterns Including Flatter Surfaces and Greater Sagittal Inclinations of Intra-articular Structures Are Reliably Identified Through an Artificial Intelligence-Based Pipeline in Anterior Cruciate Ligament-Injured Knees.

The Anterior Cruciate Ligament Injury Severity Scale (ACLISS) was developed to classify the magnitude of damage to knee structures beyond the anterior cruciate ligament (ACL) (meniscus, cartilage, collateral ligaments, etc) at the time of ACL rupture. However, its validity in predicting clinical outcomes after ACL reconstruction (ACLR) has never been assessed. To determine whether ACLISS correlates with reoperation and patient-reported functional outcomes after ACLR. Cohort study; Level of evidence, 3. The records of all patients who underwent primary ACLR at a single institution between 2019 and 2022 with minimum follow-up of 2 years were reviewed. Patients were excluded if they had concomitant collateral ligament or posterior cruciate ligament repair/reconstruction or prior ipsilateral ACLR. ACLISS scores (0-12) and grades (grade 1: scores 0-3; grade 2: scores 4-7; grade 3: scores 8-12) were determined using preoperative magnetic resonance imaging and intraoperative arthroscopic findings based on the original published technique. The primary outcome was reoperation after ACLR. Secondary outcomes included International Knee Documentation Committee (IKDC) subjective scores and Marx activity scores. Bivariable and multivariable logistic regression analyses were performed to identify predictors of reoperation. Cox proportional hazards modeling and Kaplan-Meier survival analysis were used to evaluate time to reoperation. Statistical significance was defined as a P value <.05. A total of 324 patients met the inclusion criteria. The mean age was 29.3 ± 13.6 years, and 50.9% of the patients were male. The mean follow-up was 5.1 ± 0.8 years. Of the patients, 177 (54.6%) were classified as ACLISS grade 1 damage, with a mean score of 2.3 ± 0.9; 141 (43.5%) as grade 2, with mean score of 4.8 ± 0.9, and 6 (1.9%) as grade 3, with mean score of 8.2 ± 0.4. Overall, 87 (26.9%) patients required medial meniscus repair, and 82 (25.3%) patients required lateral meniscus repair. The overall ACL revision rate was 4.0%. A total of 34 (10.5%) patients had reoperation for any reason. The mean IKDC score was 84.4 ± 14.2, and the mean Marx score was 8.6 ± 5.4. There was no significant association between ACLISS grade and reoperation rate (grade 1: 10.2%; grades 2 and 3: 10.9%; P = .832). In multivariable analysis, hybrid autograft with allograft augmentation was significantly associated with increased reoperation risk (OR, 7.68; 95% CI, 1.82-32.4; P = .006). Survival analysis revealed that patients with grades 2 and 3 experienced earlier reoperations, with 69% occurring between 5 and 15 months compared to 22% for grade 1 (P = .0086). IKDC and Marx scores did not differ significantly by ACLISS score. While ACLISS grade does not predict overall reoperation rates or functional outcomes when concomitant injuries are appropriately managed, patients with higher grades experienced earlier reoperation.

This study aimed to identify factors associated with greater quantitative pivot shift in anterior cruciate ligament (ACL)-injured knees by quantitatively assessing the pivot shift under anesthesia using a navigation system prior to ACL reconstruction. A total of 114 patients (66 males and 48 females) who underwent ACL reconstruction were included. Prior to reconstruction, the pivot shift test was performed under anesthesia and measured using a navigation system. The maximum difference in the anterior-posterior position of the tibia during knee flexion-extension without stress and during the pivot shift test-termed peak coupled anterior tibial translation (peak c-ATT)-was recorded as the quantitative value. Multiple regression analysis was used to determine factors associated with the quantitative pivot shift value, with nine independent variables: Sex, age, preoperative side-to-side difference in anterior knee laxity, time from injury to surgery, presence of medial and lateral meniscus injuries, knee extension angle, femorotibial angle, and preinjury Tegner activity score. Among the 114 participants, 80 (70.2%) had normal lateral menisci, and 34 (29.8%) had damaged lateral menisci. Multiple linear regression identified three variables significantly associated with greater quantitative pivot shift: Time from injury to surgery (standardized partial regression coefficient [β] = 0.38, p = 0.000), knee extension angle (β = 0.29, p = 0.001), and presence of lateral meniscus injury (β = 0.29, p = 0.001). Other variables-including age, sex, anterior laxity, medial meniscus injury, femorotibial angle, and Tegner score-did not reach statistical significance. Three factors-prolonged time from injury to surgery, knee hyperextension, and lateral meniscus injury-were significantly associated with greater quantitative pivot shift in ACL-injured knees. The strongest predictor was the time elapsed between injury and surgery. The level of evidence was IV: A diagnostic study of nonconsecutive patients.

The posterior horns of the medial menisci are more commonly injured during exercise. Cushioning insoles are one of the most widely used conservative interventions for preventing knee joint injuries. However, the effect of the cushion property of insoles on the knee joints with meniscal tears remain unknown. We investigated the effects of insoles with different cushioning properties on the knee joint following a radial tear of the posterior horn of the medial meniscus. Full extension landing with a heel-first strike pattern was performed by 12 participants randomly wearing ethylene vinyl acetate (EVA) and artificial cartilage foam (ACF) insoles, and the peak plantar pressures (pPP) were measured. The right knee of the participant whose pPP was closest to the median was loaded to a finite element model with radial tear. The pPP of EVA insoles (2386.42 ± 298.29N) was higher than that of ACF (2174.16 ± 270.63N) (t = 7.84, P < 0.001). The finite element analysis revealed that the peak von Mises Stress (pVMS) values of the medial and lateral menisci were 12.32MPa and 7.90MPa for injured joint with EVA, and 9.02MPa and 6.84MPa for injured joint with ACF. Hence, insoles with higher cushioning can decrease the vertical impact force and stress concentration of the knee joint after radial tear of the posterior horn of the medial meniscus.

The peroneal (fibular) nerve (PN) traverses the posterolateral aspect of the knee joint, placing it at risk during lateral meniscus (LM) repair, given its proximity to the popliteus tendon (PoT). This study aimed to evaluate the risk of PN injury and define asafe anchor penetration angle during all-inside LM repair. Aretrospective analysis was conducted using magnetic resonance imaging (MRI) scans of 327 individuals aged 18-60years. The patellar tendon (PaT) and PoT widths were measured. The PN location relative to the PoT was determined. Distances from the PN to predefined medial and lateral reference lines across the PoT were calculated. The angular relationship between these lines and the transverse axis of the PaT was also analyzed for both anteromedial (AM) and anterolateral (AL) arthroscopic portals. The PN-to-PoT distance was found to be comparable for both portals. However, the PN was significantly farther from the lateral reference line in the AM portal and from the medial reference line in the AL portal. The safe upper limit for anchor insertion was approximately 65° from the AM portal and 88° from the AL portal. Appropriate portal selection and anchor angle during all-inside LM repair can significantly reduce the risk of PN injury. The AL portal offers abroader safe insertion range and may therefore improve nerve protection.

Discoid lateral meniscus is the most common etiology for isolated meniscal pathology in the pediatric population. However, there remains a limited understanding of how complication rates vary among different age groups undergoing surgical management of a symptomatic discoid lateral meniscus. The aims of this study were to compare postoperative complication rates between age groups in pediatric patients undergoing surgical management of a symptomatic discoid lateral meniscus and assess whether patient age group is a risk factor for any complication rate that differed between the 2 age groups. Consecutive cases of discoid lateral meniscus surgeries from 2018 to 2022 were queried from the SCORE database. Demographic, perioperative, and postoperative complication data were collected and compared between patients <10 and ≥10 years old. A multivariable logistic regression was used to better understand those variables that demonstrated significant differences between age cohorts. Seven hundred sixty-three discoid lateral meniscus surgeries were identified for inclusion in this study, with 160 (20.5%) aged 10 years or younger and 603 (79.5%) 10 years or older. Postoperative stiffness was the most common complication occurring in 5.0% of patients. Overall complication rates were no different between the 2 age groups (11.9% vs. 11.9%, P =1.000). Specific complication rates were also no different between the 2 age groups with the exception that patients 10 years or younger had higher rates of postoperative stiffness than patients 10 years or older (11.3% vs. 3.3%, P <0.001) including both extension loss (6.4% vs. 1.2%, P <0.001) and flexion loss (3.1% vs. 1.7%, P <0.001). In multivariable analysis, age 10 years or younger was identified as a risk factor for postoperative stiffness when controlling for confounding variables. Specifically, patients 10 years or younger had 2.67 (95% CI: 1.12-5.86) and 3.09 (95% CI: 1.11-8.62) times the odds of developing postoperative stiffness and extension loss, respectively, compared with patients 10 years or older. This study shows that age 10 years or younger is a risk factor for developing postoperative stiffness after undergoing surgical treatment of a symptomatic discoid lateral meniscus. Level III-therapeutic, retrospective comparative study.

The posterolateral corner (PLC) structures restraining the mobility of the lateral meniscus posterior horn (LMPH) have been described in greater anatomic detail in recent years. However, biomechanical evidence regarding their functional role remains limited. The purpose was to investigate the biomechanical roles of the popliteomeniscal fascicles (PMFs), meniscofibular ligament (MFibL), lateral meniscotibial ligament (LMTL), and posterior meniscotibial ligament (PMTL) in stabilizing the LMPH. It was hypothesized that transecting the PMFs would increase mobility regardless of cutting order, that additional PLC transection would further increase instability, and that these injuries would alter knee kinematics. Controlled laboratory study. Ten fresh-frozen cadaveric knees were mounted on a 6 degrees of freedom robotic testing system. Sequential transections of the anterior PMF (aPMF), posterior PMF (pPMF), MFibL, LMTL, and PMTL were performed under 2 dissection protocols to compare the effect of cutting order between the aPMF and pPMF. LMPH anterior displacement under 10-N traction, tibial rotation during passive flexion-extension, and rotational laxity under ±5 N·m torque were measured. Differences among transection states were analyzed using linear mixed models with Bonferroni correction, with significance set at P < .05. LMPH anterior displacement significantly increased from 6.3 mm in the intact state to 8.1 to 8.4 mm after transection of either the aPMF or pPMF (P = .007) and further increased to 10.2 mm after MFibL (P < .001) and 11.4 mm after PMTL (P < .001) transection. Passive flexion significantly shifted tibial rotation toward external rotation after aPMF or pPMF transections (P = .043). Internal rotation laxity increased from 32.6° in the intact state to 36.4° after combined PMF cuts (P = .001), 37.3° after MFibL transection (P < .001), and 40.2° after PMTL transection (P < .001), whereas the external rotation laxity did not significantly change. Anterior movement of the LMPH occurred after transection of either the aPMF or pPMF, regardless of cutting order in the cadaveric model. Concomitant injury to other posterolateral structures, particularly the MFibL and PMTL, further increased this instability. PLC structures restraining the LMPH may be important for detecting abnormal meniscal motion. Assessing not only the PMFs but also the MFibL and PMTL may improve diagnostic accuracy and treatment planning.

The menisci serve as secondary stabilizers in the knee, and anterior cruciate ligament (ACL) tears have been associated with meniscal tears. Previous studies have indicated that a delay ≥12 months is associated with development of new meniscal pathology in an ACL-deficient knee. Some studies have indicated that the time period might be shorter in the pediatric and adolescent population, and other predictive factors remain poorly defined. To examine the association between time, patient-related factors, and the extent and location of meniscal pathology for patients of all ages with ACL reconstruction. Cohort study (prognosis); Level of evidence, 3. This multicenter retrospective cohort analysis of 2033 patients with ACL reconstruction, aged 9 to 73 years, included those who underwent ACL reconstruction between 2013 and 2023. Multivariable logistic regression analysis was used to model meniscal tear patterns based on age, sex, activity level, and surgery interval. Delayed ACL reconstruction (>120 days postinjury) was associated with a significantly higher prevalence of medial meniscus tears (P < .001). Multivariable analyses revealed that delayed surgery increased the odds of medial meniscus tears by 80% (adjusted odds ratio [aOR], 1.80; 95% CI, 1.47-2.21; P < .001) and both medial and lateral tears by 47% (aOR, 1.47; 95% CI, 1.10-1.97; P < .009). Furthermore, male sex was associated with an elevated prevalence for meniscal tears at all time points compared to female sex, demonstrating 43% higher odds of medial meniscus tears (aOR, 1.43; 95% CI, 1.18-1.74; P < .001), 61% higher odds of lateral meniscus tears (aOR, 1.61; 95% CI, 1.34-1.93; P < .001), and 50% higher odds of both medial and lateral meniscus tears (aOR, 1.50; 95% CI, 1.13-1.98; P < .005). These results highlight the importance of timely surgical management to mitigate progressive intra-articular damage, with special consideration for male athletes and patients at high risk for delayed intervention.

Posterolateral tibial fractures (PLTFs) are common concomitant injuries of an anterior cruciate ligament (ACL) rupture resulting in a loss of osseous support of the posterior horn of the lateral meniscus. It is unknown if the additional treatment of the PLTF brings a benefit in the treatment of symptomatic ACL-deficient knees. To evaluate the kinematic effects of various reconstruction states in an ACL-deficient knee with PLTF, compared to the native knee. Controlled laboratory study. Eight unpaired knees were tested using a 6 degrees of freedom robotic system equipped with a force-torque sensor in the following states: intact, ACL-deficient, ACL-deficient with PLTF, ACL reconstruction (ACLR) with PLTF, ACLR with lateral extra-articular tenodesis (LET) and PLTF, and ACLR with reconstructed PLTF states. Simulated laxity tests were performed at 0°, 30°, 60°, and 90° of flexion under constant loading: anterior tibial translation (ATT), internal rotation (IR), and external rotation (ER). The simulated pivot-shift (PS) test was performed at 0°, 15°, 30°, and 45° of flexion. A linear mixed model with post hoc Bonferroni corrections for multiple comparisons was performed for statistical analysis. Compared with the native state for ATT in 0° to 90°, no ACLR state showed any significant differences. ACLR with reconstructed PLTF compared to the native state presented a significant increase in IR at 60°. ACLR with LET presented a significant reduction of IR at 30° and 90° compared to the native state. In the simulated PS test, the ACLR with reconstructed PLTF showed a significantly higher ATT compared with the native state at 15° to 45°. In comparison, the ACLR with LET showed no significant differences to the native state at 0° to 45°. In line with clinical and biomechanical literature, differences in ATT ≥3 mm and rotational changes ≥3° were considered clinically meaningful thresholds. ACLR combined with LET provides superior restoration of anterior translational and rotational stability compared to ACLR alone or ACLR with PLTF repair, particularly in the PS test. Based on this biomechanical study, adding PLTF repair to ACLR for PLTFs ≤3 mm does not improve knee stability compared to standard ACLR alone. From a biomechanical point of view, there is no indication that PLTF fragments ≤3 mm should be repaired when performing ACLR.

To investigate anterior cruciate ligament (ACL) injury associated meniscal and cartilage lesions and to evaluate the independent effects of sports activity level and surgical timing on their distribution. A retrospective cohort analysis was conducted on all primary ACL reconstructions performed at a specialized sports medicine hospital between 2018 and 2022. The primary outcome was the prevalence of ACL-associated injuries. Secondary outcomes included classification of associated injuries, differences according to sports activity level, and injury-to-surgery time. Multivariate logistic regression was used as the main analysis. A total of 582 patients were included, with a median age of 26.0years. Of these, 321 (55%) had at least one meniscal tear. Cartilage lesions were identified in 93 patients (16%), most commonly affecting the medial femoral condyle (MFC). Registration in a professional sports club was associated with increased odds of lateral meniscus posterior horn tears. Surgical delay showed increasing odds of chondral lesions, particularly involving the MFC, as well as medial meniscal tears. Surgeries performed more than 30days after injury were associated with significantly lower odds of identifying ramp lesions. ACL injuries are frequently associated with a range of concomitant intra-articular lesions. Medial compartment lesions are primarily associated with surgical timing, independent of sports activity level. In contrast, lateral meniscus posterior horn tears were more common among professional athletes. Surgeries performed within 30days of injury were associated with higher odds of detecting ramp lesions, regardless of sports activity level.

Lateral meniscal (LM) tears are common in anterior cruciate ligament (ACL)-injured knees but may be underestimated on preoperative magnetic resonance imaging. Structural imaging parameters reflecting knee morphology and alignment may help identify patients at increased risk of LM injury. This study examined whether medial posterior tibial slope (MPTS), lateral posterior tibial slope (LPTS), and tibiofemoral rotation angle (TFA) are associated with LM tears in ACL injuries. This retrospective cohort study evaluated clinical records and preoperative magnetic resonance imaging (MRI) scans of patients undergoing primary ACL reconstruction. MPTS, LPTS, TFA, and delta angle were measured on standardized MRI, and LM status was confirmed arthroscopically. Multivariable logistic regression analysis identified independent associations. Restricted cubic spline (RCS) analysis assessed nonlinear dose-response patterns, and receiver operating characteristic (ROC) curves with DeLong testing quantified incremental predictive performance. A total of 215 patients were included (100 with and 115 without LM tears). Patients with tears demonstrated greater LPTS (5.9 ± 3.9° vs 4.5 ± 3.4°, p = 0.005) and TFA (2.3 ± 4.7° vs 1.0 ± 3.1°, p = 0.015), while MPTS and delta angle did not differ. After adjustment, LPTS (odds ratio [OR], 1.12; 95% confidence interval [CI], 1.03-1.21; p = 0.007), MPTS (OR, 2.48; 95% CI, 1.24-5.07; p = 0.011), and TFA (OR, 1.10; 95% CI, 1.02-1.18; p = 0.014) remained independently associated with LM tears. RCS analysis revealed a nonlinear, right-shifted U-shaped association between TFA and tear risk (P-nonlinearity < 0.001), with risk increasing at extreme rotational values, particularly increasing internal tibial rotation. ROC analysis showed modest improvements in discrimination with LPTS (area under the curve [AUC], 0.600 to 0.665; p = 0.041) and TFA tertiles (AUC, 0.600 to 0.674; p = 0.040); however, overall discrimination remained limited and these findings should be interpreted cautiously without external validation. Steeper lateral posterior tibial slope and greater tibiofemoral rotation were independent risk factors for LM tears in anterior cruciate ligament injuries. Tibiofemoral rotation showed a nonlinear increase in risk, driven mainly by excessive internal rotation. These parameters may provide additional context for preoperative risk stratification.

While recent investigations have focused on injury mechanism classifications of tibial plateau fractures (TPFs), the association between valgus TPFs and concomitant soft-tissue damage involving menisci and ligaments remains insufficiently elucidated. This study aimed to characterize intra-articular soft-tissue injuries associated with various valgus TPFs and assess the predictive value of lateral plateau depression (LPD) and widening (LPW). Additionally, the analysis extended to other injury mechanisms. This study included adult patients with acute tibial plateau fractures who had complete imaging data, excluding patients with open fractures and multiple fractures throughout the body. Imaging examinations were used to assess the fracture mechanism and intra-articular soft-tissue damage. The study retrospectively analyzed the clinical data of 138 patients with valgus injury TPFs in our hospital. The study compared the incidence of TPFs with intra-articular soft-tissue damage under different injury mechanisms. The result demonstrated that the incidence of valgus hyperextension TPFs combined with medial collateral ligament injuries was relatively high (61.5%) compared with TPFs with other injury mechanism. Multivariable logistic regression and smooth curve fitting revealed significant dose-response relationships of LPD (odds ratio [OR] = 1.408; 95% confidence interval [CI] 1.217, 1.627) and LPW (OR = 1.782; 95% CI 1.387, 2.290) with the risk of lateral meniscus (LM) tears in valgus TPFs. Receiver operating characteristic curves showed the area under the curve (AUC) values and the optimal thresholds of LPD and LPW. For all valgus TPFs, the AUCs of LPD and LPW associated with LM tear were 0.804 (95% CI 0.728, 0.880) and 0.741 (95% CI 0.657, 0.825), respectively. And the optimal threshold for LPD to predict LM tears was 7.11mm (sensitivity 0.80, specificity 0.74). Subgroup analysis by injury mechanism further demonstrated that, under the valgus extension injury mechanism, the optimal threshold was 8.45mm (sensitivity 0.68, specificity 0.91). Under the valgus flexion injury mechanism, the optimal threshold was 7.18mm (sensitivity 0.69, specificity 0.87). Further analyses revealed that varus flexion TPFs demonstrated elevated risks of anterior cruciate ligament injuries (82.5%), lateral collateral ligament injuries (65.0%), and meniscal tears (70.0%), whereas varus hyperextension TPFs showed higher posterior cruciate ligament injury prevalence (56.3%). LPD serves as a reliable predictor of fractures combined with LM tears. Specifically, under the overall valgus injury mechanism, the possibility of LM tears (particularly the posterior horn tears) should be guarded against when LPD exceeds 7.11mm. For the valgus extension subtype, the possibility of LM tears (especially the anterior horn tears) should be highly suspected when LPD exceeds 8.45mm. And for the valgus flexion subtype, an LPD exceeding 7.18mm should prompt evaluation for LM tears, particularly those affecting the posterior horn. Level 3.

Mobile-bearing unicompartmental knee arthroplasty (UKA) is prone to rotational malalignment of the femoral component. Moreover, existing biomechanical studies frequently overlook the mechanical impact of patients' bone quality on such surgical errors. To investigate the coupling effect of femoral component transverse rotation and bone quality on the biomechanical environment, a finite element model incorporating intact soft tissues was constructed. Based on bone mineral density variations, three models were established: normal bone (B1), osteopenia (B2), and osteoporosis (B3). Nine rotational conditions ranging from -14° to 14° in the transverse plane were simulated. Quantitative analysis revealed that external rotation significantly elevated the contact pressure on the polyethylene liner. Conversely, internal rotation (-14°) increased the lateral meniscus stress by approximately 16.8% compared to the neutral alignment (0°) via a "linkage mechanism". Group B3 exhibited a pseudo "cushion effect", wherein the peak strain of the tibial cancellous bone reached 5 883.9 µε, exceeding the pathological threshold of 4 000 µε; additionally, compared with Group B1, their average strain in the cortical bone increased by approximately 79.7%. In conclusion, transverse rotational malalignment of the femoral component serves as a direct mechanical trigger disrupting the biomechanical balance in UKA, and osteoporosis significantly amplifies this risk of failure. Therefore, for patients with compromised bone mass, strict neutral alignment must be pursued intraoperatively to circumvent cancellous bone microfractures and early prosthesis subsidence.

More Than 5.5 mm of Internal Rotational Tibial Subluxation Measured on Magnetic Resonance Imaging Predicts High-Grade Pivot Shift Under Anesthesia in Patients With Primary Anterior Cruciate Ligament Injury.

Lateral Meniscus Posterior Root Repair with Lateral Extra-articular Tenodesis Significantly Decreased Internal Rotation and Pivot Shift Loading in a Cadaveric Study of Anterior Cruciate Ligament Reconstructed Knees.

Delayed Posterior Cruciate Ligament Reconstruction, Older Age, and Higher Body Mass Index Are Associated With an Increased Prevalence of Concomitant Cartilage and Meniscal Injuries.