Chronic Anterior Cruciate Ligament Deficiency Research Articles

Management of Meniscus Pathology with Concomitant Anterior Cruciate Ligament Injury.

The purpose of this review is to summarize current clinical knowledge on the prevalence and types of meniscus pathology seen with concomitant anterior cruciate ligament (ACL) injury, as well as surgical techniques, clinical outcomes, and rehabilitation following operative management of these pathologies. Meniscus pathology with concomitant ACL injury is relatively common, with reports of meniscus pathology identified in 21-64% of operative ACL injuries. These concomitant injuries have been associated with increased age and body mass index. Lateral meniscus pathology is more common in acute ACL injury, while medial meniscus pathology is more typical in chronic ACL deficiency. Meniscus tear patterns associated with concomitant ACL injury include meniscus root tears, lateral meniscus oblique radial tears of the posterior horn (14%), and ramp lesions of the medial meniscus (8-24%). These meniscal pathologies with concomitant ACL injury are associated with increased rotational laxity and meniscal extrusion. There is a paucity of comparative studies to determine the optimal meniscus repair technique, as well as rehabilitation protocol, depending on specific tear pattern, location, and ACL reconstruction technique. There has been a substantial increase in recent publications demonstrating the importance of meniscus repair at the time of ACL repair or reconstruction to restore knee biomechanics and reduce the risk of progressive osteoarthritic degeneration. Through these studies, there has been a growing understanding of the meniscus tear patterns commonly identified or nearly missed during ACL reconstruction. Surgical management of meniscal pathology with concomitant ACL injury implements the same principles as utilized in the setting of isolated meniscus repair alone: anatomic reduction, biologic preparation and augmentation, and circumferential compression. Advances in repair techniques have demonstrated promising clinical outcomes, and the ability to restore and preserve the meniscus in pathologies previously deemed irreparable. Further research to determine the optimal surgical technique for specific tear patterns, as well as rehabilitation protocols for meniscus pathology with concomitant ACL injury, is warranted.

Comparison of Side-to-Side Difference in Posterior Tibial Slope in Knees With Acute Versus Chronic Anterior Cruciate Ligament Deficiency.

The posterior tibial slope (PTS) is an important feature in knee joint biomechanics and indicates anterior-posterior knee stability. Increased PTS is a known risk factor for both primary anterior cruciate ligament (ACL) rupture and postreconstruction rerupture. To investigate the effect of long-term exposure to ACL deficiency on the PTS and the sagittal anatomy of the proximal tibia. Cross-sectional study; Level of evidence, 3. A total of 44 patients (38 men, 6 women) with a history of knee injury and ACL rupture confirmed by magnetic resonance imaging and physical examination were included in this study. Patients were divided into those with chronic ACL deficiency (group 1: injured ≥5 years prior; n = 22) and acute ACL deficiency (group 2: injured <1 year prior; n = 22). The medial and lateral tibial plateau PTS and anterior tibial translation were measured on monopodal weightbearing knee radiographs at 20° of flexion. The mechanical tibiofemoral angle (MTFA) and the medial proximal tibial angle (MPTA) were measured using an orthoroentgenogram. The side-to-side difference between the affected and unaffected knees was also calculated for all measurements. The mean duration of exposure to ACL deficiency was 7.6 years (range, 5-15 years) in group 1 and 4.4 months (range, 1-11 months) in group 2. Regarding the side-to-side differences in angular measurements, a higher medial PTS (affected vs unaffected: 12.4° vs 10.1°; P = .007), higher lateral PTS (11° vs 8.9°; P = .011), and increased varus alignment on both the MTFA (4.3° vs 2.4°; P = .036) and the MPTA (84.9° vs 86.3°; P = .033) were found in group 1, while no significant differences in angular measurements were found in group 2. Compared with group 2, patients in group 1 had a significantly higher side-to-side difference in the medial PTS (2.3° vs 0.1°; P = .0001), lateral PTS (2.1° vs 0.4°; P = .0001), and MPTA (1.4° vs 0.1°; P = .002). This study showed that the affected knees of patients with chronic ACL deficiency (≥5 years) had higher medial and lateral PTS compared with the unaffected contralateral knees. Therefore, when planning ACL reconstruction for patients with a history of long-term ACL deficiency, it is crucial to measure the preoperative PTS accurately.

Chronic ACLD Knees with Early Developmental Cartilage Lesions Exhibited Increased Posterior Tibial Translation during Level Walking.

Early articular cartilage lesion (CL) is a vital sign in the onset of posttraumatic knee osteoarthritis (PTOA) in patients with anterior cruciate ligament deficiency (ACLD). Researchers have suggested that altered kinematics could accelerate CLs and, therefore, lead to the onset of PTOA. However, little is known about whether specific knee kinematics exist that lead to early CL in chronic ACLD knees. Level walking is the most frequent and relevant in vivo activity, which greatly impacts knee health. We hypothesized that the knee kinematics during level walking in chronic ACLD knees with early tibiofemoral CL would significantly differ from those of chronic ACLD knees without early tibiofemoral CL. Thirty patients with a chronic ACLD history, including 18 subjects with CLs and 12 subjects without CLs, and 35 healthy control subjects were recruited for the study from July 2020 to August 2022. The knee kinematic data during level walking were collected using a three-dimensional motion analysis system. The kinematic differences between groups were compared using statistical parametric mapping with one dimension for One-Way ANOVA. The cartilage statuses of the ACLD knees were assessed via MRI examination. The CLs distribution of subjects was evaluated using a modified Noyes scale and analyzed by chi-square tests. ACLD knees with CLs had significantly greater posterior tibial translation (7.7-8.0mm, 12%-18% gait cycle GC, p = 0.014) compared to ACLD knees without CLs during level walking. ACLD knees with CLs had greater posterior tibial translation (4.6-5.5mm, 0%-23% GC, p < 0.001; 5.8-8.0mm, 86%-100% GC, p < 0.001) than healthy controls during level walking. In the group of ACLD knees with CLs, CL is mainly located in the back of the tibia plateau and front of load bearing area of the medial femoral condyle (p < 0.05). Chronic anterior cruciate ligament deficient knees with cartilage lesions have increased posterior tibial translation compared to anterior cruciate ligament deficient knees without cartilage lesions and healthy subjects. The posterior tibial translation may play an important role in knee cartilage degeneration in ACLD knees. The increased posterior tibial translation and cartilage lesion characteristics may improve our understanding of the role of knee kinematics in cartilage degeneration and could be a helpful potential reference for anterior cruciate ligament deficient therapy, such as physical training to improve abnormal kinematic behavior.

Relationship Between Intraoperative Macroscopic Anterior Cruciate Ligament Findings, Perioperative Surgical Findings, and Postoperative Clinical Outcome After Cruciate-Retaining Total Knee Arthroplasty.

To assess how intraoperative macroscopical anterior cruciate ligament (ACL) findings affect perioperative procedures, biomarkers, and postoperative anterior-posterior (AP) laxity and range of motion (ROM) after cruciate-retaining (CR) total knee arthroplasty (TKA)and to determine how chronic ACL deficiency may affect postoperative inflammatory biomarker, AP laxity, and ROM. A total of 121 patients with varus knee osteoarthritis without a history of ACL injury who underwent ATTUNE® (DePuy Synthes, Warsaw, IN) CR TKA were analyzed. Intraoperative ACL findings were stratified into intact, damaged, and diminished, according to the tension by probing, synovial coverage, and vascularity. C-reactive protein (CRP) levels were examined at one, seven, and 14 days after surgery. Knee AP laxity measurements using Kneelax 3 (Monitored Rehab Systems, Haarlem, The Netherlands)and postoperative knee ROM were also compared. One-way ANOVA showed significant differences in CRP levels examined one day after surgery observed between the three groups (8.4 (3.8), 9.8 (4.3), and 13.2 (7.7) mg/dL, respectively; P = 0.018), with post hoc analysis showing that CRP levels one day after surgery were significantly greater in the diminished group than in the intact and damaged groups (P = 0.012 and 0.023, respectively). AP laxity in 30° of knee flexion was observed between the three groups (5.4 (2.3), 5.8 (2.5), and 7.1 (2.8) mm, respectively; P = 0.039), with post hoc analysis showing that AP laxity in 30° of knee flexion was significantly greater in the diminished group than in the intact group(P = 0.038). Knee ROM showed no significant differences. Intraoperative ACL diminishment was associated with higher CRP one day after surgery and midrange AP laxity one year after surgery.

Arthroscopic All-Suture Anchor Technique for Unstable Ramp Lesions with Medial Meniscal Defects

A ramp lesion is a specific type of tear in the meniscocapsular junction of the posterior horn of the medial meniscus, usually associated with anterior cruciate ligament (ACL) injury. Biomechanical cadaveric studies have shown that ACL injury combined with ramp lesions significantly increases anterior tibial translation and external rotation, which ACL reconstruction alone cannot completely control. Additionally, ramp lesions are sometimes associated with medial meniscal defects, especially in cases of chronic ACL deficiency after repetitive traumatic events, in which the anatomical repair of the meniscocapsular junction is infeasible. This report describes a new arthroscopic repair technique using an all-suture anchor through a posteromedial portal for unstable ramp lesions with medial meniscal defects.

The Relationship of Knee-related Quality of Life With Function, Psychological Factors, Strength, Performance, and Postural Stability After ACL Reconstruction: A Cross-Sectional Study.

Patients after anterior cruciate ligament reconstruction (ACLR) have decreased health-related quality of life (QoL) compared with healthy control participants. Few studies have verified the predictors of QoL using Quality of Life Outcome Measure Questionnaire for Chronic Anterior Cruciate Ligament Deficiency (ACL-QoL), and no study has verified the relationship of psychological factors and knee function with ACL-QoL in patients after ACLR. Knee functional status, muscle strength, performance in hop tests, postural stability, and psychological factors would be the predictors of QoL after ACLR. Cross-sectional study. Level 4. A total of 131 participants who had undergone ACLR at least 6 months previously were evaluated. QoL was assessed using ACL-QoL; knee functional status, using International Knee Documentation Committee Subjective Knee (IKDC) and global rating scale (GRS); psychological readiness, using Anterior Cruciate Ligament Return to Sport after Injury Scale (ACL-RSI); kinesiophobia, using Tampa Scale for Kinesiophobia (TSK-17); knee strength, using isokinetic dynamometer; performance, using single-leg hop tests; and postural stability, using Biodex Balance System. Pearson's linear correlation and stepwise hierarchical multiple linear regression analyses were performed to verify the predictors of QoL. ACL-QoL showed a moderate correlation with IKDC (r = 0.69), GRS (r = 0.55), ACL-RSI (r = 0.50), and TSK-17 (r = -0.49). ACL-QoL presented none to low correlations with the variables of muscle strength, postural stability, and performance in hop tests. The variables related to the knee functional status and psychological factors (IKDC, GRS, ACL-RSI, and TSK-17) were found to be the predictors of QoL (R2 = 0.56; P = 0.01). Knee functional status, psychological readiness, and kinesiophobia were the predictors of knee-related QoL in patients after ACLR. These results can assist clinicians in the therapeutic monitoring of the factors that may interfere with QoL in patients after ACLR.

Combined Meniscus Repair and Anterior Cruciate Ligament Reconstruction

AbstractMeniscal tear patterns associated with anterior cruciate ligament (ACL) tears, such as root tears and ramp lesions are common but less easily recognized on magnetic resonance imaging (MRI) compared with a complete radial tear or a locked bucket-handle tear. Timely treatment of these tears improves outcomes in the setting of ACL reconstruction. While physical examination does not enable a definitive diagnosis of meniscal root tears and ramp lesions, high-grade laxity, including a 3+ Lachman and 3+ pivot shift, should raise suspicions for these tear patterns. MRI allows visualization of both root tears and ramp lesions, although the gold standard for diagnosis is probing at the time of arthroscopy due to a high false-negative rate on MRI. Up to 17% of patients with an ACL tear have a lateral meniscal root tear; a contact mechanism and increased posterior slope are both associated with a greater incidence of lateral meniscal root tears and these are repaired with a tunnel technique. Meniscal ramp lesions occur in up to 41% of patients with ACL tears due to a contact mechanism, and we prefer repair with an inside-out technique. More than 60% of complete radial meniscal tears occur in the setting of ACL tears and are preferentially repaired with a hashtag technique for minimally separated tears and a 2-tunnel technique combined with an inside-out repair for more severe tears. Bucket-handle tears are more common in the setting of chronic ACL deficiency; concurrent with ACL reconstruction urgent meniscal repair with an inside-out technique is the gold standard, which allows for precise approximation of the tear with multiple points of fixation for improved biomechanical performance. It is critical to identify and treat these tears during ACL reconstruction because of their role as secondary stabilizers and for long-term chondral protection.

Autologous chondrocyte implantation combined with anterior cruciate ligament reconstruction: similar short-term results in comparison with isolated cartilage repair in ligament intact joints

PurposeBoth acute ruptures of the anterior cruciate ligament (ACL) as well as chronic ACL insufficiency show a high association with focal cartilage defects of the knee. However, the results after combined ACL reconstruction and cartilage repair are not well investigated. The aim of the present study was to investigate the short-term outcomes after autologous chondrocyte implantation (ACI) in combination with ACL reconstruction and to compare the results with patients who underwent isolated ACI in ligament intact knees.MethodsAll patients who were registered in the German Cartilage Registry with ACI for focal cartilage defects in the knee joint in combination with ACL reconstruction and who completed the 24 month follow-up were included in the study group. A matched-pair procedure according to gender, defect location, defect size, and age was used to create a control group of patients with isolated ACI in ACL intact joints. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and the numeric analog scale for pain (NAS) were used to assess the preoperative state as well as the clinical outcomes 12 and 24 months after surgery.ResultsA total of 34 patients were included in both the study group (age mean 33.3 ± SD 8.8 years) and the control group (33.6 ± 8.4 years) with a median defect size of 466 (25%-75% IQR 375–600) mm2 and 425 (IQR 375–600) mm2, respectively. In comparison with the preoperative state (median 67, IQR 52–75), the study group showed a significant increase of the total KOOS after 12 months (78, IQR 70–86; p = 0.014) and after 24 months (81, IQR 70–84; p = 0.001). The NAS for pain did not change significantly in the postoperative course. In comparison with the control group there was no significant difference for the total KOOS neither preoperative (control group median 67, IQR 52–73) nor at any postoperative time point (12 months: 82, IQR 67–93; 24 months: 81, IQR 71–91).ConclusionThe clinical short-term outcomes after ACI at the knee joint in combination with ACL reconstruction are good and similar to the results after isolated ACI in ligament intact knees.Level of evidenceIII.

Arthroscopic incidence of lateral meniscal root avulsion in patients with anterior cruciate ligament injury

BackgroundTo arthroscopically evaluate the incidence of lateral meniscal root avulsion (LMRA) and associated intra-articular injuries in patients undergoing anterior cruciate ligament (ACL) reconstruction.Materials and MethodsFrom April 2014 to March 2017, 532 consecutive patients were diagnosed as having an ACL injury and underwent arthroscopic ACL reconstruction. The diagnosis of LMRA was made arthroscopically. The effects of gender, activity, grade of laxity, time from injury, and concomitant meniscal lesions were analyzed.ResultsAmong 532 patients, 497 (93.4%) underwent primary ACL reconstruction and 35 (6.5%) underwent revision procedures. 383 were acute or subacute injuries (less than 6 months from injury to surgery) and 149 chronic (more than 6 months). Average age was 30.4 years (DS: ± 11.04); there were 422 (79.3%) males and 110 (20.6%) females. A LMRA associated with the ACL injury was detected in 72 cases (13.5%), with a significant prevalence observed in males ({chi ^2} = 4.65; P = 0.031, statistically significant). In the 149 patients with a chronic injury, 27 patients had LMRA (18.1%), while 45 of the 383 patients with an acute or subacute injury had LMRA (11.7%). There was a tendency, albeit not significant ({chi ^2} = 3.721; P = 0.054), for the prevalence to increase with time since the initial ACL injury. LMRA was significantly associated ({chi ^2} = 7.81; P = 0.006) with a meniscocapsular tear of the posterior horn of the medial meniscus (ramp lesion). No other significant associations, such as with severity of A-P translation (as measured by KT-2000) or activity level, were detected.ConclusionLMRA is a relatively common injury associated with both acute and chronic ACL tears. A relatively high incidence in cases of chronic ACL insufficiency suggests that LMRAs do not heal spontaneously or that they may appear with time, even when absent at the time of the initial injury.Level of evidenceLevel III, cross-sectional study.

Meniscal problems in the ACL deficient knee: What every ACL surgeon must be able to do!

Meniscal tears are common concomitant injuries seen in up to 65% of anterior cruciate ligament (ACL) deficient knees. The goal of ACL reconstruction (ACL-R) is to restore mechanical stability to the knee and to prevent further damage to the menisci, which act as secondary knee stabilizers for both anterior-posterior translation and rotational laxity. Delayed ACL-R and chronic ACL insufficiency have been associated with secondary meniscal tears that are more likely to be complex tears. Excluding graft failure, another common cause of reoperation in ACL reconstructed knees is meniscal surgery. Therefore, addressing meniscal tears at time of primary ACL-R is important to restore joint mechanics, protect the ACL graft for successful healing, and prevent long-term osteoarthritis. Current management options include leaving tears in-situ, meniscectomy, or meniscus repair. However, inconsistent findings have identified the need for well-defined treatment recommendations. Surgical decision making is reliant upon multiple factors such as adequate understanding of meniscal anatomy, biomechanics, tear pattern, and patient factors. This review focuses on the impact of meniscus injuries in ACL deficient knees and addresses current surgical indications and outcomes.

Effect of walking on in vivo tibiofemoral cartilage strain in ACL-deficient versus intact knees

Anterior cruciate ligament (ACL) rupture alters knee kinematics and contributes to premature development of osteoarthritis. However, there is limited data regarding the in vivo biomechanical response of tibiofemoral cartilage to activities of daily living (ADLs) in ACL-deficient knees. In this study, eight otherwise healthy participants with chronic unilateral ACL deficiency completed a stress test to assess the effect of 20 min of level treadmill walking at a speed of 2.5 mph on tibiofemoral cartilage in their ACL-deficient and contralateral ACL-intact knees. Three-dimensional surface models developed from pre- and post-activity magnetic resonance (MR) images of the injured and uninjured knees were used to determine compressive strain across multiple regions of tibiofemoral cartilage (medial and lateral tibial plateaus, medial and lateral femoral condyles, medial aspect of femoral condyle adjacent to intercondylar notch of the femur). In the ACL-deficient knees, we observed significantly increased cartilage strain in the region of the medial femoral condyle adjacent to the intercondylar notch (6% in deficient vs. 2% in contralateral, p = 0.01) as well as across the medial and lateral tibial plateaus (4% vs. 3%, p = 0.01) relative to the contralateral ACL-intact knees. Increased compressive strain at the medial intercondylar notch and tibial plateau suggests alterations in mechanical loading or the response to load in these regions, presumably related to altered knee kinematics. These changes may disrupt cartilage homeostasis and contribute to subsequent development of osteoarthritis.

Slope-Reducing Tibial Osteotomy Combined With Primary Anterior Cruciate Ligament Reconstruction Produces Improved Knee Stability in Patients With Steep Posterior Tibial Slope, Excessive Anterior Tibial Subluxation in Extension, and Chronic Meniscal Posterior Horn Tears

Background: Steep posterior tibial slope (PTS; >13°), excessive anterior tibial subluxation (ATS) in extension (>10 mm), and meniscus posterior horn tears (MPHTs) have been identified to be associated with primary anterior cruciate ligament (ACL) reconstruction (ACLR) failure. Recent studies have reported that steep PTS is directly correlated with excessive ATS in extension and concomitant MPHTs, especially for those patients with chronic (>6 months) ACL deficiency. There is increasing biomechanical evidence that slope-reducing tibial osteotomy decreases ATS in extension and protects the ACL graft. Hypothesis: Slope-reducing tibial osteotomy combined with primary ACLR is effective for producing improved knee stability in patients with steep PTS (>13°), excessive ATS in extension (>10 mm), and concomitant chronic MPHTs (>6 months). Study Design: Case series; Level of evidence, 4. Methods: Between June 2016 and January 2018, 18 patients with ACL injuries who had steep PTS (>13°), excessive ATS in extension (>10 mm), and concomitant chronic MPHTs (>6 months) underwent slope-reducing tibial osteotomy combined with primary ACLR. The PTS and anterior subluxation of the lateral and medial compartment (ASLC and ASMC) in extension before and after the index procedures were regarded as primary clinical outcomes. Moreover, Lysholm score, Tegner activity score, International Knee Documentation Committee (IKDC) objective grade, pivot-shift test, and KT-1000 side-to-side difference were evaluated preoperatively and at the minimum 2-year follow-up visit. Results: The mean PTS was 18.5° (range, 17°-20°) preoperatively and 8.1° (range, 7°-9°) postoperatively (P < .01). The mean ASLC and ASMC in extension were 12.1 mm and 11.9 mm preoperatively, which reduced to 1.0 mm and 1.5 mm at the last follow-up visit (P < .05). In addition, all of the following showed significant improvements (pre- vs postoperatively): mean Lysholm score (46.5 vs 89.5; P < .05), mean Tegner activity score (5.7 vs 7.3; P < .05), IKDC objective grading results (18 grade D vs 14 grade A and 4 grade B; P < .05), pivot-shift tests (15 grade 2+ and 3 grade 3+ vs 18 grade 0; P < .01), and KT-1000 side-to-side difference (13.0 mm vs 1.6 mm; P < .01). Moreover, no graft reruptures were found at the final follow-up visit. Conclusion: In this study, slope-reducing tibial osteotomy combined with primary ACLR effectively improved knee stability in patients with steep PTS (>13°), excessive ATS in extension (>10 mm), and concomitant chronic MPHTs (>6 months).

Three-dimensional realignment and slope reducing osteotomy with anatomic ACL reconstruction in patients with revision anterior cruciate ligament deficiency

Introduction:Current incidence of recurrent anterior cruciate ligament (ACL) instability is 5%, but revision surgery is challenging and requires a thorough analysis of potential risk factor. Moreover, recurrent and chronic ACL instability can result in medial tibio-femoral osteoarthritis (OA). Beside various soft tissue patterns, bony morphologies like a steep posterior tibial slope are associated with an increased anterior tibial translation (ATT) and rotatory instability in the ACL deficient knee. To address the instability and the osteoarthritis a combined procedure is necessary in these patients, however, little is known about the efficacy of such combined procedures. Therefore, the objective of this study was to evaluate the patient reported outcomes and knee stability following combined high tibial osteotomy (HTO) with ACL reconstruction in middle-aged patients with recurrent or chronic cruciate ligament deficiency and mild to moderate medial compartment osteoarthritis (OA). Hypotheses: Methods:Surgical reports and prospectively collected patient reported outcome scores (IKDC, Lysholm, WOMAC, VAS for pain, and Tegner activity score) as well as clinical examination were evaluated retrospectively with a mean follow up of 45.2 ± 14.7 months. Inclusion criteria were 1) high tibial osteotomy with concomitant anatomic ACL reconstruction. Data at final followup were compared to baseline values using the Wilcoxon signed rank test (p < 0.05).Results:44 patients met the inclusion criteria. 16/44 suffered a graft failure after primary ACL reconstruction, and 8/44 had chronic ACL instability, but had a previous subtotal medial meniscus resection. Mean patient age at surgery was 38.2 ± 10.5 years (range: 18 – 63) with a mean varus alignment of 4.5° ± 1.5°. All patient reported significantly improved outcome scores at final follow-up (VAS 4.3 to 1.5, Lysholm 52.4 to 73.5, IKDC 56.5 to 70.9). However, the change in Tegner score at final follow-up (3.4 to 4.5) was not significant. At final followup 25/44 patients had a removal of the fixation plate.Conclusion:The results of this study indicate, that high tibial osteotomy combined with anatomic single bundle ACL reconstruction is a good treatment option in active middle aged patients suffering from recurrent or chronic ACL deficiency with mild to moderate medial compartment OA. At a median follow-up of 24 months patient reported outcome scores were improved. Especially in patients with multiple ACL reconstruction failures realignment osteotomies should be considered.

Meniscal ramp lesions should be considered in anterior cruciate ligament-injured knees, especially with larger instability or longer delay before surgery.

To determine the incidence of meniscal ramp lesions in an anterior cruciate ligament (ACL) injured knees and to clarify whether ramp lesions are related to chronic ACL deficiency and increased knee instability. Consecutive ACL injured patients were evaluated arthroscopically for a ramp lesion via a trans-notch view and evidence of menisco-capsular injury was recorded. Other concomitant injuries to the knee were also noted. Incidence of meniscal ramp lesions, delay before surgery, and anterior-posterior stability was analyzed. All patients underwent bilateral KT-2000 evaluation. One hundred and three consecutive ACL injured patients with a mean age of 24years were included in this study. In total, a ramp lesion was found in 10 knees (9.7%) via a trans-notch view. None of these lesions could be identified by the standard view from the anterolateral portal. Other medial meniscal lesions were found in 26 knees (25.2%) by standard arthroscopic viewing. The ramp lesion group had significantly longer delay before surgery with a median of 191days (p < 0.01) as well as a larger side-to-side difference of KT-2000 measurement (7.3 ± 1.8mm; p < 0.01), compared with the intact medial meniscus group (53days and 5.5 ± 1.5mm, respectively). Ramp lesions that were identified using a trans-notch view were not visualized with standard arthroscopic views. Increased anterior tibial translation and longer delay before surgery were seen in knees with ramp lesions. Careful inspection of the posteromedial menisco-capsular region is required as hidden menisco-capsular lesions may occur which may result in residual knee instability. Level II.

Muscle training in chronic anterior cruciate ligament insufficiency--a comparative study

The aim of the investigation was to study and compare the effect of two basically different training methods on muscle strength and knee function on a consecutive and prospective series of 26 conservatively treated patients with chronic anterior cruciate ligament injury. The two training models were: model Q directed towards specific training of knee extensor muscle strength and model F aiming at training of the lower extremity and trunk muscles in functional weightbearing patterns. The parameters evaluated were: isometric and isokinetic muscle strength, a performance test (one-leg hop test), and a functional score. The results after a three-month training period showed in both groups a significant increase of muscle strength in both knee extensors and knee flexors. No significant difference of isokinetic strength values between the two groups was observed. The isometric gain of knee extension was significantly higher in the Q group. The one-leg hop test value and the functional score were also significantly increased in both groups. However, the hop test indicated a more favourable result in the group who were trained functionally.

Detecting the presence of anterior cruciate ligament injury based on gait dynamics disparity and neural networks

The aim of this study is to develop a new pattern recognition-based method to model and discriminate gait dynamics disparity between anterior cruciate ligament (ACL) deficient (ACL-D) knee and contralateral ACL-intact (ACL-I) knee in patients with unilateral ACL deficiency by using kinematic features and neural networks. Thereby the capabilities of these features to detect the presence of injury can be assessed. The proposed method consists of two stages. In the first (training) stage, gait analysis is performed. A two-dimensional five-link biped model used for imitating human gait locomotion is employed to demonstrate that functions containing kinematic data of lower extremities, including knee and hip flexion/extension angles and angular velocities, characterize the gait system dynamics. Knee angle-hip angle cyclograms, knee and hip angle-angular velocity phase portraits visually demonstrate the significant disparity of gait dynamics between the lower extremities of patients with unilateral ACL deficiency. Gait dynamics underlying gait patterns of ACL-D and ACL-I knees are locally accurately modeled and approximated by radial basis function (RBF) neural networks via deterministic learning theory. The derived knowledge of approximated gait dynamics is preserved in constant RBF networks. In the second (classification) stage, a bank of dynamical estimators is constructed using the preserved constant RBF networks to represent the learned training gait patterns. By comparing the set of estimators with a test gait pattern, the generated average $$L_1$$ norms of errors are taken as the disparity and classification measure between the training and test gait patterns to differentiate between ACL-D and ACL-I knees. Finally, experiments are carried out on forty-three patients to assess the effectiveness of the proposed method. By using the leave-one-out cross-validation style under normal and fast walking speed conditions, the correct classification rates for discriminating between ACL-D and ACL-I knees are reported to be 95.61$$\%$$ and 93.03$$\%$$, respectively. Compared with other state-of-the-art methods, the results demonstrate that gait alterations in the presence of chronic ACL deficiency can be visualized through cyclograms and phase portraits, and can be detected with superior performance.

Motor imagery in high-functioning individuals with chronic anterior cruciate ligament deficiency: A cross-sectional study

BackgroundThere is increasing evidence that motor imagery performance (MIP) is impaired in conditions that have a component of movement dysfunction. However, MIP has not been investigated in people with chronic anterior cruciate ligament (ACL) deficiency who experience limited disability and function at high levels. HypothesisThis study had three objectives: (1) to assess implicit MIP in individuals with a chronic ACL deficient (ACLD) knee compared with healthy controls (i.e., intact anterior cruciate ligament); (2) to determine if the location of ACL deficiency affects MIP (dominant versus non-dominant leg); and (3) to determine if impairment in MIP is specific to the side (injured versus non-injured) of ACL deficiency. MethodsForty-five participants with chronic ACLD knee and 44 healthy controls completed a left/right judgement task of pictured knees using the “Recognise” app to evaluate implicit MIP. Accuracy and reaction time of judgements were compared between groups. Additionally, within the chronic ACLD knee group, we made comparisons between the dominant ACLD knee and non-dominant ACLD knee subgroups and between the injured knee and the non-injured knee of the ACLD group. ResultsThere were no differences in implicit MIP between the ACLD knee and the control group, the non-injured knee versus injured knee of the ACLD knee group, or the dominant ACLD knee versus non-dominant ACLD knee subgroups. ConclusionImplicit MIP is not disrupted in high functioning individuals with chronic ACLD knee.

Classification of Gait Patterns Using Kinematic and Kinetic Features, Gait Dynamics and Neural Networks in Patients with Unilateral Anterior Cruciate Ligament Deficiency

The anterior cruciate ligament (ACL) plays an important role in controlling knee joint stability. The literature provides conflicting information on whether patients with ACL deficiency exhibits gait adaptations. The aim of this study is to investigate if the use of neural networks with a new pattern recognition-based method can differentiate gait patterns between ACL deficient (ACL-D) knee and contralateral ACL-intact (ACL-I) knee in patients with unilateral ACL deficiency. The proposed method is divided into two stages. In the training stage, kinematic and kinetic gait variables are measured and compared between the two lower extremities. Gait dynamics underlying gait patterns of ACL-D and ACL-I knees are locally accurately modeled and approximated by radial basis function (RBF) neural networks via deterministic learning theory. The derived knowledge of approximated gait dynamics is preserved in constant RBF networks. In the classification stage, a bank of dynamical estimators is constructed using the preserved constant RBF networks to represent the learned training gait patterns. By comparing the set of estimators with a test gait pattern, the generated average $$L_1$$ norms of errors are taken as the difference and classification measure between the training and test gait patterns. Finally, experiments are carried out on forty-three patients to assess the effectiveness of the proposed method. By using the leave-one-out cross-validation style under normal and fast walking speed conditions, the correct classification rates for discriminating between ACL-D and ACL-I knees are reported to be 95.9 $$\%$$ and 94.0 $$\%$$ , respectively. Compared with other state-of-the-art methods, the results demonstrate that gait alterations in the presence of chronic ACL deficiency can be detected with superior performance and support the validity of the proposed method.

Side-to-Side Differences in Varus Thrust and Knee Abduction Moment in High-Functioning Individuals With Chronic Anterior Cruciate Ligament Deficiency

Background: There is evidence that frontal plane knee joint motion plays a crucial role in the pathogenesis of knee osteoarthritis, yet investigation of individuals with chronic anterior cruciate ligament–deficient (ACLD) knees remains sparse. Purpose: To investigate (1) if individuals with chronic ACLD knees demonstrate higher biomechanical measures of medial knee load as compared with their anterior cruciate ligament–intact (ACLI) knees, (2) if differences in static knee alignment of the ACLD knee will demonstrate a difference in the magnitude of biomechanical measures of medial knee load when compared with the ACLI knee, and (3) the side-to-side concordance of varus thrust among individuals with chronic ACLD knees. Study Design: Descriptive laboratory study. Methods: Participants were sourced from a metropolitan orthopaedic surgeon group. Those who met the inclusion criteria and agreed to participate underwent a 3-dimensional gait analysis assessment to measure knee adduction moment (KAM), knee flexion moment (KFM), KAM peaks, KAM impulse, and varus thrust. Frontal plane knee static alignment was measured with a digital inclinometer fixed to medical calipers. The participants were divided according to their static knee alignment (neutral, varus, and valgus) for subgroup analysis. Peak knee angular velocity and frontal plane knee angle were used to establish if a participant was walking with a knee thrust. An individual was deemed to have knee thrust during gait if the largest frontal plane knee movement coincided with the peak knee angular velocity that occurred within the first 30% of stance phase. Results: Forty-five participants were recruited. The mean (SD) time from injury was 34.5 (55.6) months. ACLD knees did not demonstrate higher mean KAM and KFM (P > .5) or early-stance peak KAM (P = .3-.8) and KAM impulse (P = .3-.9) as compared with ACLI knees as a whole group or when the varus, neutral, and valgus alignment subgroups were investigated separately. Twenty-three percent (n = 9) of the participants had a varus thrust at the ACLD or ACLI knee, 44% (n = 4) had a varus thrust at the ACLD knee, and 22% (n = 2) had varus thrust at both knees. Conclusion: There were no side-to-side differences in mean KAM and KFM and early-stance peak KAM and KAM impulse among high-functioning individuals with chronic unilateral ACLD knees. There was a low prevalence of varus thrust among high-functioning individuals with chronic unilateral ACLD knees.

Chronicity of Anterior Cruciate Ligament Deficiency, Part 2: Radiographic Predictors of Early Graft Failure.

Background:Accumulating evidence suggests that long-term anterior cruciate ligament (ACL) deficiency can give rise to an abnormal tibiofemoral relationship and subsequent intra-articular lesions. However, the effects of chronic ACL deficiency (ACLD) on early graft failure after anatomic reconstruction remain unclear.Hypothesis:We hypothesized that patients with long-term ACLD lasting more than 5 years would have a greater rate of early graft failure due to insufficient intraoperative reduction of the tibia and that the preoperative and immediately postoperative abnormal tibiofemoral relationship in the sagittal plane, such as anterior tibial subluxation (ATS), would correlate with the graft status on postoperative magnetic resonance imaging (MRI).Study Design:Cohort study; Level of evidence, 3.Methods:A total of 358 patients who had undergone anatomic ACL reconstruction with hamstring grafts were divided into 5 groups based on chronicity of ACLD: (1) 0 to 6 months, (2) 6 months to 1 year, (3) 1 to 2 years, (4) 2 to 5 years, and (5) longer than 5 years. Preoperatively and immediately postoperatively, lateral radiographs in full extension were taken in all patients to evaluate the tibiofemoral relationship, specifically with regard to ATS, space for the ACL (sACL), and extension angle. All patients underwent MRI at 6 months to reveal graft status. Groups with a high rate of graft failure were further analyzed to compare demographic and radiographic factors between the intact and failure subgroups, followed by multivariate logistic regression analysis to identify predisposing factors.Results:Graft failure without trauma was observed in 4 (1.8%), 0 (0%), 1 (3.7%), 3 (9.7%), and 8 patients (17.7%) in groups 1, 2, 3, 4, and 5, respectively. Of the 76 patients in groups 4 and 5, significant differences were noted between the failure and intact subgroups in preoperative ATS (4.9 vs 2.4 mm, respectively; P < .01), side-to-side differences in sACL (sACL-SSD) (4.7 vs 1.9 mm, respectively; P < .01), extension deficit (4.4° vs 1.3°, respectively; P < .01), and chondral lesions (P = .02), while postoperative ATS and sACL-SSD showed no differences. Multivariate logistic regression analysis revealed that of these factors, preoperative sACL-SSD could be a risk factor for early graft failure (odds ratio, 3.2; 95% CI, 1.37-7.46).ConclusionEarly graft failure at 6 months increased in patients with ACLD longer than 2 years. In this population, preoperative sACL-SSD was the most significant risk factor for early graft failure on MRI. However, immediately postoperative radiographic measurements had no effect on graft failure rates.