Pivot-shift Test Research Articles

Ramp lesions of the medial meniscus are associated with greater preoperative anterior knee laxity in anterior cruciate ligament injury.

To assess the incidence of ramp lesions in anterior cruciate ligament (ACL) injuries and to compare preoperative knee laxity between the patients with and without ramp lesions by using an electromagnetic measurement system (EMS). Two hundred six patients who underwent primary ACL reconstruction with preoperative EMS measurements were retrospectively enrolled in the present study. The diagnoses of the ramp lesions were made by arthroscopic inspections. The patients with ramp lesions and no other meniscal lesions were allocated to 'ramp group', and the patients without any meniscal lesions were allocated to 'control group'. Before ACL reconstruction under general anaesthesia, the side-to-side difference (SSD) in anterior tibial translation (ATT) during Lachman test (mm) and tibial acceleration (m/s2) of posterior tibial reduction during the pivot-shift test was measured using the EMS. The SSD in tibial internal/external rotation angle (°) at 30, 60 and 90 were further measured using the EMS. The SSD in ATT using KT-2000 was also measured. Knee laxity measurements were compared between two groups using unpaired Student's t test. Ramp lesions were observed in 30 patients (14.7%). Subsequently, 17 patients were allocated to 'ramp group' and 77 patients to 'control group', and there were no statistical differences with regard to background demographics. ATT-SSD during Lachman test was significantly greater in 'ramp group' (9.1 [95% confidence interval, CI: 5.7-12.5] mm vs. 6.2 [95% CI: 5.1-7.3] mm, p = 0.037). However, SSD in ATT with KT-2000, tibial acceleration during pivot-shift test, and SSD in tibial rotational angles were not significantly different between the two groups. Presence of ramp lesion was associated with increased anterior knee laxity during Lachman test, suggesting ramp lesions may need to be addressed at the time of ACL reconstruction. IV.

Influence of Injury to the Kaplan Fibers and Anterolateral Ligament on Pivot-Shift Phenomenon in Adult and Adolescent Patients With Anterior Cruciate Ligament Injury: A Retrospective Cohort Study

Background: Studies have shown that Kaplan fibers (KFs) play a role in controlling anterolateral rotatory knee laxity in anterior cruciate ligament (ACL) injury. However, recent clinical studies have suggested that KF injuries are not associated with a higher-grade pivot shift in knees with acute ACL injuries. Purpose: To compare the effect of KF and anterolateral ligament injury on anterolateral rotatory laxity as measured by the pivot-shift test in both adult and adolescent patients with acute ACL injury. Study Design: Cross-sectional study; Level of evidence, 3. Methods: This study consisted of patients who experienced primary acute ACL tears between January 2019 and December 2021. The magnetic resonance imaging examinations and pivot-shift tests for these individuals were conducted within 14 days after injury. Variables associated with concomitant injury were included in a binary logistic regression model to evaluate risk factors of a high-grade pivot shift and a KF injury. Results: The study included 540 patients with acute ACL tears (64 adolescent patients and 476 adults). The main risk factor for a high-grade pivot shift after acute ACL injury in adults was partial or total disruption of anterolateral ligament continuity (odds ratio [OR], 2.271; 95% CI, 1.499-3.442). In adolescent patients, the main risk factor was KF injury (OR, 19.98; 95% CI, 2.367-168.669), including edema and disruption of continuity. Conclusion: The main risk factor for a high-grade pivot shift after acute ACL injury differs between adolescent patients and adults: the KF injury sign in adolescent patients indicates a higher-grade pivot shift.

Comparison of a full tibial tunnel or an all-inside technique for anterior cruciate ligament reconstruction: An observational study.

This study aims to compare the effectiveness of anterior cruciate ligament (ACL) reconstruction performed with either a full tibial tunnel technique or an all-inside technique. Data from patients with ACL rupture who underwent ACL reconstruction using autogenous hamstring tendon grafts between January 2019 and July 2021 were retrospectively reviewed. Patients were followed up for a minimum of 24 months. Preoperative and postoperative International Knee Documentation Committee scores, Lysholm knee scores, visual analog scale pain scores, Tegner activity scale scores, C-reactive protein levels, erythrocyte sedimentation rate, white blood cell (WBC) count, D-dimer levels, and neutrophils were recorded. At the final follow-up, side-to-side differences were assessed with the pivot shift test, Lachman test, anterior drawer test, and a knee laxity-testing device. This study included 135 patients with ACL rupture, with 62 patients (43 males and 19 females, mean age: 34.42 ± 12.79 years) undergoing the full tibial tunnel technique, and 73 patients (58 males and 15 females, mean age: 32.41 ± 11.01 years) undergoing the all-inside techniques (AITs). There were no significant differences in postoperative International Knee Documentation Committee scores, Lysholm knee scores, or Tegner activity scale scores, except at postoperative 6 months. visual analog scale pain scores showed significant improvement in patients that underwent the AIT compared to the full tibial tunnel technique at postoperative 1 week, 2 weeks, and 1 month; however, there were no significant differences at postoperative 3, 6, 12, 18, and 24 months. C-reactive protein levels, erythrocyte sedimentation rate, WBC count, D-dimer levels, and neutrophils were significantly lower in patients that underwent the AIT compared to the full tibial tunnel technique at postoperative 1 month, but there were no other significant differences in these outcome measures, except for WBC count at postoperative 3 months. There was no significant difference in knee stability at the last follow-up. In ACL reconstruction, functional outcomes following the AIT are satisfactory and similar to the total tibial tunnel technique, but patients experience less pain and a reduced early postoperative inflammatory response. These results highlight the promising potential of AITs in the clinical management of ACL rupture and advocate for their widespread adoption.

The Incidence of Injuries to Ramp Semimembranosus Complex Lesions After ACL Injury: An MRI Study

Background: Medial meniscal ramp lesions have recently been an area of interest because of their recognized prevalence in association with anterior cruciate ligament (ACL) ruptures. Anatomically, the medial meniscal ramp is composed of the meniscocapsular ligament in continuity with the semimembranosus muscle and the meniscotibial ligament. Diagnosis of ramp semimembranosus complex (RSC) injuries remains challenging, and their prevalence is likely to be underestimated in comparison with ramp lesions. Purpose: To determine the prevalence of RSC lesions after a complete ACL rupture. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective database analysis was performed. The cohort consisted of the first 100 patients with complete ACL rupture confirmed by magnetic resonance imaging (MRI) who underwent knee arthroscopy for ACL reconstruction in 2019. The semimembranosus lesions were identified using MRI by 2 independent radiologists specializing in musculoskeletal imaging. The ramp lesions were initially diagnosed using MRI and then confirmed during arthroscopy by an experienced knee surgeon. The magnitude of rotatory instability was recorded using the pivot-shift test. A multivariate analysis was used to determine the lesions associated with the semimembranosus complex. Results: Of 100 patients, 53 showed lesions of the RSC; among them, 30 ramp lesions were confirmed after arthroscopic evaluation, and 40 semimembranosus lesions (23 without ramp lesion and 17 with ramp lesion) were found using MRI. A positive pivot shift was present in 57% of patients with combined RSC injury ( P = .04) compared with 36% in patients without an RSC lesion. Conclusion: Lesions of the RSC were found in more than half of ACL ruptures in this retrospective cohort. Rotational instability could be associated with combined ACL and RSC injury.

Reduced Knee Flexion Strength 18 Years After ACL Reconstruction With Hamstring Tendon Versus Patellar Tendon

Background: Bone–patellar tendon–bone (BPTB) and double-looped semitendinosus and gracilis (hamstring) grafts are commonly used for anterior cruciate ligament (ACL) reconstruction. Short-term and midterm studies show little or no differences between the 2 grafts; however, there are only a few long-term studies to compare results between the 2 grafts. Purpose: To compare the results after using either BPTB grafts or hamstring tendon grafts 18 years after ACL reconstruction. Study Design: Randomized controlled trial; Level of evidence 2. Methods: A total of 114 patients with ACL rupture between 2001 and 2004 were randomized to reconstruction with either a BPTB graft or a hamstring tendon graft. Patients were operated on at 4 major hospitals. The 18-year follow-up evaluation included anterior knee laxity measured with a KT-1000 arthrometer, defined as the primary outcome, while clinical examination (Lachman and pivot-shift tests), isokinetic testing of muscle strength, patient-reported outcome measures, and an assessment of radiographic osteoarthritis using the Kellgren-Lawrence classification were defined as secondary outcomes. Results: A total of 96 patients (84%, 47 BPTB and 49 hamstring grafts) were available for follow-up, 71 of these for clinical examination. Seven of 96 patients were excluded for ACL revision (n = 5) or knee replacement (n = 2) surgery. In total, 25 patients (10 BPTB and 15 hamstring grafts) had undergone additional surgery other than ACL revision or total knee arthroplasty. There were no significant differences between the groups in terms of anterior laxity test with KT-1000 arthrometer (primary outcome). In secondary outcomes, no significant differences between groups were reported regarding clinical examination, patient-reported outcome scores, or radiographic osteoarthritis (Kellgren-Lawrence grade 2-4 for patellofemoral joint [18 hamstring and 14 BPTB] or tibiofemoral joint [20 hamstring and 19 BPTB]), while isokinetic testing revealed that the hamstring group had a 10.7% reduction in mean peak flexion torque compared with the BPTB group at 60 deg/s (df = 59; P = .011). At 60 deg/s the mean total flexion work in the hamstring group was reduced by 17.2% compared with the BPTB group (df = 59; P = .002). Conclusion: The flexion strength in the hamstring group was significantly reduced in the operated knee after 18 years. There were no significant differences between the groups regarding subjective outcomes, patient-reported outcomes, range of motion, clinical and instrumented knee laxity, and the development of osteoarthritis. Registration: NCT05876013 (ClinicalTrials.gov identifier).

Proximally positioned femoral grafts decrease passive anterior tibial subluxation in anterior cruciate ligament reconstruction using a posterior trans-septal portal.

To compare the anterior and posterior trans-septal (TS) portal approaches in anterior cruciate ligament reconstruction (ACLR) by evaluating femoral tunnel positioning and passive anterior tibial subluxation (PATS). A total of 205 patients who underwent primary ACLR using the outside-in technique between March 2018 and December 2021 were retrospectively enrolled. Patients were classified into two groups based on the viewing techniques: the anterior group was treated using anteromedial or anterolateral portals (n = 155), and the TS group was treated using posterior TS portal (n = 55). The relative locations of the femoral tunnel were evaluated using the deep-shallow planes (X-axis) and superior-inferior planes (Y-axis) with the quadrant method in the lateral femoral condyle on a 3-dimensional computed tomography image. Anterior tibial subluxation for the lateral and medial compartments relative to the femoral condyles was evaluated as measured on magnetic resonance imaging. Knee laxity was assessed using the pivot-shift test and stress radiography. In the posterior TS group, the femoral tunnel was usually located deeper on the X-axis and more superior on the Y-axis, which corresponds to a more proximal position, than in the anterior group (deeper on the X-axis and superior on the Y-axis). Moreover, the femoral tunnel locations in this group were more compactly distributed than those in the anterior group. The TS group showed significantly better reduction of postoperative PATS in the lateral compartments than the anterior group (anterior group vs. TS group: lateral compartment, 3.2 ± 3.1 vs. 4.5 ± 3.2mm; p = .016). Significantly better results were found in the TS group for knee stability as assessed by the pivot-shift grade (p = .044); however, there were no significant differences between the two groups with respect to patient-reported outcome measures (p > .05) and other complications (p = .090). Our results suggest that positioning the femoral tunnel using the posterior TS portal approach may lead to better outcomes in terms of PATS and rotational stability compared to the anterior portal approach in ACLR.

Posterior Cruciate Buckling Angle Variations Are Associated with Different Patterns of Medial Meniscus Tears in Anterior-Cruciate-Deficient Knees: Results of a Prospective Comparative Magnetic Imaging Resonance Study.

The diagnosis of anterior cruciate ligament (ACL) tear relies on clinical evaluation and magnetic resonance imaging (MRI). Direct and indirect signs of ACL tear have been described with MRI evaluation. Posterior cruciate ligament (PCL) buckling has been described as an indirect radiographic sign of an ACL tear. The aim of the present study was to assess the variations in PCL buckling angles in patients with ACL tears and in patients with isolated lesions in the posterior horn of the medial meniscus. In addition, the influence of different patterns of medial meniscus tears in ACL-deficient knees was investigated. Finally, the influences of risk factors such as tibial slope, delay from injury to surgery, absence of medial meniscus tear, degree of Lachman and pivot shift testing were also assessed. This was a cohort study. A total of 154 patients (78 in the group with ACL tear and 76 in the control group) were assessed with MRI and lateral weight-bearing X-ray to assess PCL buckling angle and tibial slope by two independent observers. The presence of a medial meniscus bucket handle or ramp lesion of the medial meniscus was assessed and recorded at the time of surgery. PCL buckling angle measurement was highly reliable, with an ICC of 0.866 and 0.894, respectively, in the study group and the control group for interobserver reliability. The intrarater reliability was found to be high in PCL buckling angle for the study group [ICC = 0.955] and the control group [ICC = 0.943]. The mean angle in patients with ACL tear was 110.7 ± 15.2° and 115.3 ± 16.2° (for the two examiners) and 111.4 ± 12° and 114 ± 14.5° (for the two examiners) in patients with an intact, healthy ACL. An association emerged between bucket handle tears of the medial meniscus (p = 0.010) and a decreased PCL buckling angle and between ramp lesions of the medial meniscus and increased PCL buckling angle both (p = 0.024). Good inter- and intraobserver reliability for the measurement of the PCL buckling angle was observed. Increased PCL buckling angle values were observed in patients with concomitant ACL and bucket handle tears of the medial meniscus, while decreased angle values were observed in those who had ACL tear and ramp lesion of the medial meniscus. No statistically significant difference in the PCL buckling angle emerged between patients with ACL tears and those who had a healthy, intact ACL.

ACL reconstruction combined with anterolateral structures reconstruction for treating ACL rupture and knee injuries: a finite element analysis.

Introduction: The biomechanical indication for combining anterolateral structures reconstruction (ASLR) with ACL reconstruction (ACLR) to reduce pivot shift in the knee remains unclear. This study aims to investigate knee functionality after ACL rupture with different combinations of injuries, and to compare the effectiveness of ALSR with ACLR for treating these injuries. Methods: A validated finite element model of a human cadaveric knee was used to simulate pivot shift tests on the joint in different states, including 1) an intact knee; 2) after isolated ACL rupture; 3) after ACL rupture combined with different knee injuries or defect, including a posterior tibial slope (PTS) of 20°, an injury to the anterolateral structures (ALS) and an injury to the posterior meniscotibial ligament of the lateral meniscus (LP); 4) after treating the different injuries using isolated ACLR; v. after treating the different injuries using ACLR with ALSR. The knee kinematics, maximum von Mises stress (Max.S) on the tibial articular cartilage (TC) and force in the ACL graft were compared among the different simulation groups. Results and discussion: Comparing with isolated ACL rupture, combined injury to the ALS caused the largest knee laxity, when a combined PTS of 20° induced the largest Max.S on the TC. The joint stability and Max.S on the TC in the knee with an isolated ACL rupture or a combined rupture of ACL and LP were restored to the intact level after being treated with isolated ACLR. The knee biomechanics after a combined rupture of ACL and ALS were restored to the intact level only when being treated with a combination of ACLR and ALSR using a large graft diameter (6mm) for ALSR. However, for the knee after ACL rupture combined with a PTS of 20°, the ATT and Max.S on the TC were still greater than the intact knee even after being treated with a combination of ACLR and ALSR. The finite element analysis showed that ACLR should include ALSR when treating ACL ruptures accompanied by ALS rupture. However, pivot shift in knees with a PTS of 20° was not eliminated even after a combined ACLR and ALSR.

Effect of Preoperative Anterolateral Ligament Injury on Outcomes After Isolated Acute ACL Reconstruction With Hamstring Graft: A Prospective Study With Minimum 5-Year Follow-up

Background: The potential influence of a preoperative anterolateral ligament (ALL) lesion seen on magnetic resonance imaging (MRI) on the mid- and long-term surgical outcomes of anterior cruciate ligament (ACL) reconstruction is still controversial. Purpose: To evaluate the clinical outcomes and failure rate of isolated ACL reconstruction at a minimum 5-year follow-up in patients with and without ALL injury diagnosed preoperatively using MRI. Study Design: Cohort study; Level of evidence, 2. Methods: A prospective cohort of patients with acute ACL injury was divided into 2 groups based on the presence (ALL injury group) or absence (control group) of ALL injury on preoperative MRI. This is a longer-term follow-up study of a previously published study that had a minimum 2-year follow-up. Both groups underwent anatomic isolated reconstruction of the ACL. The Lysholm and subjective International Knee Documentation Committee scores, KT-1000 arthrometer and pivot-shift tests, reconstruction failure rate, incidence of contralateral ACL injury, presence of associated meniscal injury, and presence of knee hyperextension were evaluated. The evaluation at the 5-year follow-up was also compared with the same patient’s evaluation at 2 years of follow-up. Results: A total of 156 patients were evaluated. No significant differences were found between the groups in the preoperative evaluation. In the postoperative evaluation, patients in the ALL injury group had a higher reconstruction failure rate (14.3% vs 4.6% for the control group; P = .049) and worse clinical outcomes according to the Lysholm scores (85.0 ± 10.3 vs 92.3 ± 6.6; P < .00001). Although the pivot-shift test results were similar, anteroposterior translation using the KT-1000 arthrometer revealed worse results for the ALL injury group (2.8 ± 1.4 mm vs 1.9 ± 1.3 mm; P = .00018). Patients in the ALL injury group also had an increase in KT-1000 arthrometer values from 2 to 5 years (2.4 ± 1.6 vs 2.8 ± 1.4; P = .038). Patients in the control group had no differences in outcomes from 2 to 5 years of follow-up. Conclusion: Combined ACL and ALL injuries were associated with significantly less favorable outcomes than were isolated ACL injuries at a minimum follow-up of 5 years after isolated ACL reconstruction with hamstring autograft. Patients with concomitant ALL injury showed a higher failure rate and worse functional scores. Also, knee stability tended to slightly worsen from 2 to 5 years in cases of associated ALL injury.

Overconstraint Associated With a Modified Lemaire Lateral Extra-Articular Tenodesis Is Decreased by Using an Anterior Femoral Insertion Point in a Cadaveric Model

To investigate tibiofemoral knee kinematics when shifting the femoral insertion point of the modified Lemaire lateral extra-articular tenodesis (LET) anterior to the lateral epicondyle. Six fresh-frozen human knee joints were tested on a test bench in the following states: (1) native, (2) anterolateral insufficient, (3) original Lemaire (oLET; insertion point: 4 mm posterior and 8 mm proximal to the epicondyle), (4) anterior Lemaire (aLET; insertion point: 5 mm anterior and 5 mm proximal to the epicondyle). Internal tibial rotation was statically investigated under an internal tibial torque of 5 Nm in 0°, 30°, 60°, and 90° of flexion. Anterior translation was statically investigated during a simulated Lachman test with an anterior translational force of 98 N. Additionally, the range of internal tibial rotation and anterior translation were dynamically investigated by a simulated pivot-shift test. Tibiofemoral kinematics were measured using an optical 3D motion analysis system. The aLET showed an internal tibial rotation comparable to the native state for all tested flexion angles except 90° (0°: P= .201; 30°: P= .118; 60°: P= .126; 90°: P= .026). The oLET showed an internal tibial rotation below the values of the native state for all tested flexion angles indicating an overconstraint (0°: P= .003; 30°: P= .009; 60°: P= .029; 90°: P= .029). Direct comparisons between aLET and oLET showed a significantly decreased overconstraint at 0° and 30° of flexion (P= .001 and P= .003, respectively) when using the aLET. No differences in anterior translation and internal tibial rotation were found between the oLET and aLET during simulated Lachman andpivot-shift test (P > .05), approximating the native state. An anteriorly shifted LET insertion point restored internal tibial rotation after anterolateral insufficiency to the native state while decreasing the overconstraint of internal tibial rotation induced by an LET using the originally described insertion point for small flexion angles ≤30°. Using an LET insertion point anterior to the epicondyle was recently reported to lower the risk of tunnel interference and has now been shown to restore internal tibial rotation effectively invitro in the course of the present study. Concerns of overconstraining internal tibial rotation are not diminished by this technique, but using an anterior insertion point helps to decrease overconstraint.

Subjective grade of apprehension during the pivot-shift test reflects patient-reported outcomes more than conventional pivot-shift test grade after ACL reconstruction.

To investigate whether the pivot-shift test reflects patient-reported outcomes 1 year after anterior cruciate ligament (ACL) reconstruction based on a multicentre prospective cohort study. This study included patients who underwent primary ACL reconstruction using the hamstring tendons. The pivot-shift test grades were determined according to the International Knee Documentation Committee (IKDC) form as 0, 1+, 2+ or 3+. In addition, patients' subjective apprehension during the pivot-shift test were classified as 0 (no-apprehension), 1+ (mild-apprehension), 2+ (moderate-apprehension) or 3+ (severe-apprehension). In this study, a positive pivot-shift test was defined as grade 1+ or higher. A total of 837 patients were enroled in this study. One year postoperatively, there was no significant difference in the Knee injury and Osteoarthritis Outcome Score (KOOS), IKDC score, Lysholm knee scale and Tegner activity scale between the positive (118 patients) and negative (719 patients) groups of the conventional IKDC grading of the pivot-shift test. However, when divided into two groups based on the apprehension grading of the pivot-shift test after surgery, the postoperative scores were significantly lower in the apprehension-positive group (114 patients) than those in the apprehension-negative group (723 patients) on the Tegner activity scale and KOOS Symptom, Sports/Rec and Quality of Life subscales. Patients' subjective apprehension during the pivot-shift test after ACL reconstruction was significantly associated with the postoperative Tegner activity scale and three subscales of the KOOS. However, there was no association between the conventional IKDC grading of the pivot-shift test and any patient-reported outcomes postoperatively. Level II.

Effect of different degrees of primary varus knee on short-term effectiveness of anterior cruciate ligament reconstruction

To investigate whether different degrees of primary varus knee affect joint function and stability in patients undergoing anterior cruciate ligament (ACL) reconstruction. A clinical data of 160 patients with primary varus knee, who were admitted between January 2020 and December 2021 and met the selection criteria, was retrospectively analyzed. All patients underwent primary ACL reconstruction using autologous single-bundle hamstring tendon. Patients were divided into three groups based on the hip-knee-ankle angle (HKA): group A (64 patients with HKA 0°-3°), group B (55 patients with HKA 3°-6°), and group C (41 patients with HKA 6°-9°). Except for the significant difference in HKA among the three groups ( P<0.05), baseline data such as age, gender, affected side, body mass index, interval between injury and operation, Kellgren-Lawrence grading, posterior tibial slope, proportion of combined meniscal injuries, Tegner score, Lysholm score, and International Knee Documentation Committee (IKDC) objective score, anterior drawer test, Lachman test, pivot shift test, and the results of KT1000 (side-to-side difference, SSD) showed no significant difference ( P>0.05). At last follow-up, joint stability was assessed through the anterior drawer test, Lachman test, pivot shift test, and SSD; joint function was evaluated using the Tegner score, Lysholm score, and IKDC objective score. All incisions in the three groups healed by first intention after operation. All patients were followed up 24-31 months, with an average of 26 months; there was no significant difference in the follow-up time among the three groups ( Z=0.675, P=0.714). At last follow-up, the knee stability and functional assessment indicators in each group significantly improved when compared to preoperative ones ( P<0.05); there was no significant difference among the three groups ( P>0.05) in terms of the anterior drawer test, Lachman test, pivot shift test, IKDC objective scores, and the changes of the Lysholm scores and Tegner scores. The Kellgren-Lawrence grading and HKA at last follow-up were consistent with preoperative results in the three groups. Varying degrees of primary varus knee do not affect early knee joint stability and functional recovery after ACL reconstruction, and there is no significant difference in effectiveness between different degrees of varus knee.

Combined Anterolateral Ligament Reconstruction Results in Better Knee Stability and More Satisfactory Subjective Outcomes in Non-Athlete Patients Undergoing Revision Anterior Cruciate Ligament Reconstruction.

Background: Consensus has not yet been reached regarding combined anterior cruciate ligament reconstruction (ALLR) with revisional anterior cruciate ligament reconstruction (RACLR). We aimed to compare the clinical outcomes between patients who underwent isolated RACLR and those who underwent RACLR combined with ALLR. Methods: Between June 2010 and June 2021, 49 patients who underwent RACLR were retrospectively reviewed over a 24-month follow-up. Patients were categorized into the isolated RACLR (n = 37, group 1) or combined ALLR group (n = 12, group 2). Clinical outcomes were evaluated with several patient-reported outcome measures (PROMs) and minimal clinically important differences (MCIDs) for each PROM. The side-to-side difference (SSD) of the anterior instability was measured. The pivot-shift test was performed. Results: Baseline characteristics showed no differences between the groups. PROMs showed no significant differences between the groups at the 2-year follow-up. Group 2 was superior to group 1 in the MCID achievement rate for Lysholm knee and International Knee Documentation Committee (IKDC) subjective scores at 24 months postoperatively. At the final follow-up, the proportion of IKDC grade A in SSD for anterior laxity was higher in group 2 than in group 1 (58.3% versus [vs.] 18.3%, p = 0.009), and the proportion of pivot-shift grade 0 was also higher in group 2 (66.7% vs. 27.0%, p = 0.013). The "near return to activity" rate was also higher in group 2 than in group 1 (83.3% vs. 45.9%, p = 0.043). Conclusions: Combining ALLR with RACLR in non-athletes results in a higher proportion of patients with less mechanical graft failure and satisfactory clinical outcomes.

Mobile App for Enhanced Anterior Cruciate Ligament (ACL) Assessment in Conscious Subjects: "Pivot-Shift Meter".

Anterior cruciate ligament (ACL) instability poses a considerable challenge in traumatology and orthopedic medicine, demanding precise diagnostics for optimal treatment. The pivot-shift test, a pivotal assessment tool, relies on subjective interpretation, emphasizing the need for supplementary imaging. This study addresses this limitation by introducing a machine learning classification algorithm integrated into a mobile application, leveraging smartphones' built-in inertial sensors for dynamic rotational stability assessment during knee examinations. Orthopedic specialists conducted knee evaluations on a cohort of 52 subjects, yielding valuable insights. Quantitative analyses, employing the Intraclass Correlation Coefficient (ICC), demonstrated robust agreement in both intraobserver and interobserver assessments. Specifically, ICC values of 0.94 reflected strong concordance in the timing between maneuvers, while signal amplitude exhibited consistency, with the ICC ranging from 0.71 to 0.66. The introduced machine learning algorithms proved effective, accurately classifying 90% of cases exhibiting joint hypermobility. These quantifiable results underscore the algorithm's reliability in assessing knee stability. This study emphasizes the practicality and effectiveness of implementing machine learning algorithms within a mobile application, showcasing its potential as a valuable tool for categorizing signals captured by smartphone inertial sensors during the pivot-shift test.

Factors Associated with Return to Sport After Anterior Cruciate Ligament Reconstruction: A Focus on Athletes Who Desire Preinjury Level of Sport.

In most previous studies investigating return to preinjury level of sport (RTPS) after anterior cruciate ligament reconstruction (ACLR), whether patients continue aiming for RTPS not only before but also after ACLR was unclear because environmental and social factors were not considered. Herein, we aimed to evaluate factors associated with RTPS among athletes who desired to achieve RTPS even after ACLR, excluding patients who no longer desire this goal owing to environmental and social factors. Ninety-two patients who underwent primary double-bundle ACLR with a minimum 2-year follow-up and desired to achieve RTPS before surgery were retrospectively enrolled. Twelve (13%) patients who no longer desired to achieve RTPS after ACLR owing to environmental and social factors were excluded. Sixty-nine patients were included in the final cohort. At the final follow-up, the patients were split into two groups: those who achieved (R group) or did not achieve (N group) RTPS based on patient self-assessment. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and Lysholm scores were also determined. The anterior tibial translation in the Lachman test and acceleration and external rotational angular velocity (ERAV) in the pivot shift test were measured at the hardware removal operation. Significant differences were observed for preinjury level of sports between the groups (p < 0.05). The rate of RTPS in competitive athletes was lower than that in recreational athletes (20/46: 43% vs. 16/22: 73%; p =.037). Lysholm score, KOOS symptom, pain, and quality of life showed higher values in the R group than in the N group (p < 0.050). Acceleration was significantly lower in the R group than in the N group (p = 0.028). Competitive level of sports is a risk factor for failure to achieve RTPS. The postoperative functional outcomes in the group that achieved RTPS showed more favorable results. These results provide important information to enable the surgeons to consider the appropriate surgical plan for competitive athletes who desire to achieve RTPS after ACLR.

Male Sex, Revision Surgery, Low Volume of Anterior Cruciate Ligament Remnant, and Significant Instability Are Risk Factors for Posterior Root Tear of the Lateral Meniscus in Patients Undergoing Anterior Cruciate Ligament Reconstruction

PurposeThis multicenter study aimed to determine the incidence of lateral meniscus posterior root tears (LMPRTs) in patients undergoing ACL reconstruction and identify associated risk factors. MethodsWe conducted a retrospective, multicenter study using data from the Francophone Arthroscopic Society's registry. The study included all the patients in the registry who underwent ACL reconstruction surgery between June 2020 and June 2023, we excluded incomplete data. We compared delay from injury to surgery between LMPRTs group and No LMPRTs group. Variables investigated as potential risk factors for LMPRTs included age, sex, nature of surgery (primary or revision), pivot shift test result, side-to-side laxity under anesthesia, presence of ACL remnant, occurrence of medial meniscal tear, and presence of collateral ligament injury. Risk factors were analyzed using a logistic regression model. ResultsAmong the 5359 patients analyzed, LMPRTs occurred in 7.0% (n=375) of cases during ACL reconstruction. Mean age at surgery was 29.3 +/- 10.3 years old [11-77]. Concerning delay to surgery, the mean time was 8.4 +/- 23.1 weeks [0.0-347.2] in the No LMPRTs group and 6.5 +/- 10.2 weeks [0.2-61.6] in the LMPRTs group (p = 0.109). Univariate analysis revealed that male sex (p < 0.001), revision surgery (p < 0.001), medial meniscal injury (p = 0.007), ACL remnant (0% vs > 70%, <10% vs > 70%, 10 to 30% vs > 70%, 30 to 50% vs > 70%, 50 to 70% vs > 70%; p < 0.001) and higher pivot shift grade (p = 0.011) were significantly associated with a presence of LMPRTs. Age, side-to-side laxity, and collateral ligament injury were not found to be significant risk factor In multivariate analysis : male sex, revision surgery, pivot shift test result and a low volume of ACL remnant remained significant. Side to side laxity was also a significant factor in multivariate analysis. ConclusionThis study identified male sex, revision surgery, low volume of ACL remnant, side to side laxity and higher grade of pivot shift as significant risk factors for LMPRTs during ACL reconstruction.

Tibial-sided Anterolateral Ligament Injuries Are Associated With Poor Healing and Residual Pivot Shift Testing After Anterior Cruciate Ligament Reconstruction

Purpose; to investigate if tibial sided anterolateral ligament (ALL) injuries are associated with poor healing and residual pivot shift. Methods; Patients who underwent anterior cruciate ligament reconstructions within postinjury 6 weeks from January 2008 to March 2021 were included. They had concomitant ALL injury confirmed by preoperative magnetic resonance imaging (MRI) and were followed minimum 20 months. Preoperative ALL injury was graded by the Muramatsu classification and postoperative ALL healing were graded by a modification of the Lee classification (good, partial, and non-visualized). The patients were allocated to an improved group (IG) and an unimproved group (UG) based on a comparison of pre- and postoperative MRI. ALL tear site, postoperative knee stability, Lysholm score, and Tegner activity scale (PROs) were compared between the two groups. Results; 128 patients were enrolled. 94.5 % patients achieved the minimal clinically important difference (MCID) for PROs, respectively. The ALL was torn at the femoral side in 46.9% patients, at mid-substance in 31.2.%, and at tibial side in 21.9%, Preoperatively, 86 (67.2%) patients had a partial tear and 42 (32.8%) patients had a complete tear. Based on the postoperative MRI appearances, 38 (29.7%) and 90 (70.3%) patients were allocated to the IG and UG, respectively. The tibial side tears were significantly frequent in UG (p= .032). Pivot shift showed a significantly higher incidence in UG than IG (p=.004). Lachman test and PROs did not differ between the two groups. Conclusions; Tibial-sided ALL tears occurred in 18.7% of the UG compared to 3.2% of the IG, and 45.6% of the UG had a postoperative grade 1 or 2 pivot shift, compared to 15.8% of the IG. Percentages of patients with the MCID for PROs did not differ between the two groups. However, the clinical relevance is limited by a high transfer bias.

Externally validated treatment algorithm acceptably predicts nonoperative treatment success in patients with anterior cruciate ligament rupture.

This study aims to develop and externally validate a treatment algorithm to predict nonoperative treatment success or failure in patients with anterior cruciate ligament (ACL) rupture. Data were used from two completed studies of adult patients with ACL ruptures: the Conservative versus Operative Methods for Patients with ACL Rupture Evaluation study (development cohort) and the KNee osteoArthritis anterior cruciate Ligament Lesion study (validation cohort). The primary outcome variable is nonoperative treatment success or failure. Potential predictor variables were collected, entered into the univariable logistic regression modeland then incorporated into the multivariable logistic regression model for constructing the treatment algorithm. Finally, predictive performance and goodness-of-fit were assessed and externally validated by discrimination and calibration measures. In the univariable logistic regression model, a stable knee measured with the pivot shift test and a posttrauma International Knee Documentation Committee (IKDC) score <50 were predictive of needing an ACL reconstruction. Age >30 years and a body mass index > 30 kg/m2 were predictive for not needing an ACL reconstruction. Age, pretrauma Tegner score, the outcome of the pivot shift testand the posttrauma IKDC score are entered into the treatment algorithm. The predictability of needing an ACL reconstruction after nonoperative treatment (discrimination) is acceptable in both the development and the validation cohort: area under the curve = resp. 0.69 (95% confidence interval [CI]: 0.58-0.81) and 0.68 (95% CI: 0.58-0.78). This study shows that the treatment algorithm can acceptably predict whether an ACL injury patient will have a(n) (un)successful nonoperative treatment (discrimination). Calibration of the treatment algorithm suggests a systematical underestimation of the need for ACL reconstruction. Given the limitations regarding the sample size of this study, larger data sets must be constructed to improve the treatment algorithm further. Level II.

In Vitro Assessment of Knee Joint Biomechanics Using a Virtual Anterior Cruciate Ligament Reconstruction.

Understanding the biomechanical impact of injuries and reconstruction of the anterior cruciate ligament (ACL) is vital for improving surgical treatments that restore normal knee function. The purpose of this study was to develop a technique that enables parametric analysis of the effect of the ACL reconstruction (ACLR) in cadaver knees, by replacing its contributions with that of a specimen-specific virtual ACLR that can be enabled, disabled, or modified. Twelve ACLR reconstructed knees were mounted onto a motion simulator. In situ ACLR graft forces were measured using superposition, and these data were used to design specimen-specific virtual ACLRs that would yield the same ligament force-elongation behaviors. Tests were then repeated using the virtual ACLR in place of the real ACLR and following that in ACL deficient knee by disabling the virtual ACLR. In comparison to the ACL deficient state, the virtual ACLRs were able to restore knee stability to the same extent as real ACLRs. The average differences between the anterior tibial translation (ATT) of the virtual ACLR versus the real ACLR were +1.6 ± 0.9 mm (p = 0.4), +2.1 ± 0.4 mm (p = 0.4), and +1.0 ± 0.9 mm (p = 0.4) during Anterior drawer, Lachman and Pivot-shift tests, respectively, which is small in comparison to the full ATT range of motion (ROM) of these knees. Therefore, we conclude that a virtual ACLR can be used in place of real ACLR during biomechanical testing of cadaveric knees. This capability opens the door for future studies that can leverage parameterization of the ACLR for surgical design optimization.

Clinical outcomes of primary anterior cruciate ligament reconstruction using six-strand hamstring autograft

Objectives: Quadrupled and five-strand hamstring tendon (HT) autografts are commonly used in anterior cruciate ligament reconstruction (ACLR), but there is significant variability in graft diameter. The six-strand HT autograft has been introduced to increase graft diameter in patients with undersized HT grafts and may achieve better clinical outcomes. None of the studies has reported clinical outcomes following this technique in Indian patients. We investigated clinical outcomes in patients who underwent primary ACLR using a six-strand HT autograft technique with a minimum six-month follow-up. Materials and Methods: Fifty-five patients who underwent primary ACLR using six-strand HT autografts with interference screw fixation were included in the study. These patients were followed up at three and six months for the evaluation of clinical outcomes. Subjective evaluations included the TegnerLysholm score, anterior cruciate ligament-quality-of-life (ACL-QOL) score, and International Knee Documentation Committee (IKDC) subjective score. Laxity assessments of the knees were performed using the Lachman test and the pivot-shift test. Functional evaluation of the patients was performed with an overall IKDC objective score. Results: The mean IKDC subjective score was significantly improved at three-month (63.42 ± 5.38) and six-month (82.82 ± 7.49) follow-up after surgery (P &lt; 0.05) when compared with pre-operative scores (50.55 ± 1.84). A similar finding was also noted with the Tegner-Lysholm score and ACL-QOL score in our study. All patients have achieved normal to near-normal functional outcomes at six months in our study without any major complications. The most commonly found complication was paresthesia (21.80%) in the present study. Conclusion: In the primary ACLR, six-strand hamstring autograft achieves similar clinical outcomes and complications as reported with four-strand or five-strand HT autografts. However, the percentages of patients who achieved normal to near-normal outcomes were higher in the present study (100%) as compared to earlier reported data using four-strand or five-strand HT autografts (~85%). The six-strand graft technique is a useful means of increasing graft diameter when faced with an undersized hamstring graft.