ACL-reconstructed Knees Research Articles

Preoperative Knee Instability Affects Residual Instability as Evaluated by Quantitative Pivot-Shift Measurements During Double-Bundle ACL Reconstruction.

Background:The pivot-shift test is an important indicator of functional outcomes after anterior cruciate ligament (ACL) reconstruction (ACLR). Preoperative instability as indicated by the pivot-shift test is associated with residual instability after ACLR. Few studies have used quantitative means to evaluate the pivot shift after ACLR.Purpose:To investigate the relationship between preoperative and residual instability and to identify the risk factors for residual instability by using quantitative measurements of the pivot shift.Study Design:Case-control study; Level of evidence, 3.Methods:A total of 91 patients undergoing primary double-bundle ACLR were retrospectively enrolled. Quantitative measurements of instability for ACL-deficient knees (ACLD) and uninjured contralateral knees (intact) preoperatively, as well as ACLR knees intraoperatively, were performed under general anesthesia using the pivot-shift test, with inertial sensors to measure acceleration and external rotational (ER) angular velocity. The ratios of intact to ACLD (ACLD/I) and intact to ACLR (ACLR/I) were measured. Patients who showed an ACLR/I of >1 were classified into the residual instability group, and those with an ACLR/I of ≤1 were classified into the noninstability group. Regarding demographic, surgical, and quantitative measurement factors, between-group comparisons and multivariate logistic regression were conducted for predictors of residual instability. Receiver operating characteristic curves were used to evaluate the correlations between ACLD/I and ACLR/I and the cutoff value of ACLD/I in predicting residual instability.Results:The predictive factors for intraoperative residual instability included female sex (odds ratio [OR], 0.3 [95% CI, 0.1-0.9]; P = .034) and ACLD/I for acceleration (OR, 1.6 [95% CI, 1.2-2.1]; P < .001), and ACLD/I for ER angular velocity (OR, 1.9 [95% CI, 1.2-3.1]; P = .013). Correlations between ACLD/I and ACLR/I were moderate with respect to both acceleration (r = 0.435; P < .001) and ER angular velocity (r = 0.533; P < .001). The cutoff points for ACLD/I were 4.9 for acceleration (sensitivity, 65.1%; specificity, 85.7%; area under the curve [AUC], 0.76) and 2.4 for ER angular velocity (sensitivity, 80.0%; specificity, 50.0%; AUC, 0.74).Conclusion:Greater preoperative instability was a risk factor for residual instability as measured intraoperatively by a quantitatively evaluation in the pivot shift during ACL reconstruction. Quantitative measurements of instability during the pivot shift mechanism under general anesthesia may enable surgeons to predict postoperative residual instability.

Partial meniscectomy does not affect the biomechanics of anterior cruciate ligament reconstructed knee with a lateral posterior meniscal root tear.

The purpose of this study was to determine the effects of a lateral meniscus posterior root tear, partial meniscectomy, and total meniscectomy on knee biomechanics in the setting of anterior cruciate ligament (ACL) reconstruction. Thirteen fresh-frozen cadaver knees were tested with a robotic testing system under an 89.0-N anterior tibial load at full extension (FE), 15°, 30°, 60° and 90° of knee flexion and a simulated pivot-shift loading (7.0 Nm valgus and 5.0 Nm internal tibial rotation) at FE, 15° and 30° of knee flexion. Anterior tibial translation (ATT) and the in-situ force of ACL graft under the different loadings were measured in four knee states: (1) ACL reconstruction with intact lateral meniscus (Intact meniscus), (2) ACL reconstruction with lateral meniscal posterior root tear (Root tear), (3) ACL reconstruction with lateral posterior partial meniscectomy (Partial meniscectomy) and (4) ACL reconstruction with total lateral meniscectomy (Total meniscectomy). Under anterior tibial loading, compared with an intact meniscus, root tear significantly increased ATT at 15° and 30° of knee flexion (p < 0.05) and partial meniscectomy had almost same increased ATT as with root tear at any knee flexion between FE and 90°. Under simulated pivot-shift loading, total meniscectomy increased ATT compared with intact meniscus, root tear, partial meniscectomy at FE (p < 0.05). Under anterior tibial and simulated pivot-shift loading, partial meniscectomy has no significant effect on the stability of ACL-reconstructed knee with lateral meniscal posterior root tear, while total meniscectomy increased laxity at less than 30° of knee flexion. Clinically, in cases of irreparable meniscal root tears or persistent pain a partial meniscectomy can be considered in the setting of ACL reconstruction.

Lateral extra-articular tenodesis in patients with revision anterior cruciate ligament (ACL) reconstruction and high-grade anterior knee instability

BackgroundAdditional lateral extra-articular procedures can reduce the risk of failure of primary anterior cruciate ligament reconstruction (ACLR). There is limited evidence on the effect of lateral extra-articular procedures in revision ACL surgery. The purpose of this study was to evaluate the clinical outcome of patients with lateral extra-articular tenodesis (LET) in combination with revision ACLR for combined ACL graft failure and high-grade anterior knee instability. MethodsBetween 2016 and 2018, 75 patients with graft failure after primary ACLR and high-grade anterior knee instability who received revision ACLR were included in the retrospective study. High-grade anterior knee instability was defined as high-grade pivot-shift or side-to-side difference of more than six millimeters in Rolimeter®-testing. An additional modified Lemaire tenodesis was performed in 59 patients during revision ACLR. Seventy-three patients were clinically examined with a minimum of two years after revision surgery. ResultsFailure of the revision ACLR occurred in 8.2% (n = 6) of the cases. LET lead to significant decreased failure rates (five percent vs. 21%, p = .045) and decreased incidence of a positive pivot-shift in patients with revision ACLR and high-grade anterior knee instability in comparison to patients without LET. Also, postoperative functional scores were significantly increased in the group of additional LET. ConclusionsAdditional LET in patients with revision ACLR and high-grade anterior instability significantly reduces the risk of failure of revision ACLR, the incidence of pivot-shift and increases postoperative functional outcome.

Meniscal Allograft Transplantation After Anterior Cruciate Ligament Reconstruction Can Improve Knee Stability: A Comparison of Medial and Lateral Procedures

Background: The purpose of this study was to evaluate the clinical score and stability after meniscal allograft transplantation (MAT) after a previous anterior cruciate ligament (ACL) reconstruction. Hypothesis: Medial MAT would improve anteroposterior stability, and lateral MAT would improve rotational stability. Study Design: Cohort study; Level of evidence, 3. Method: We retrospectively investigated 31 cases of MAT after a previous total or nearly total meniscectomy and ACL reconstruction between November 2008 and June 2017. Cases were divided into medial (16 cases) and lateral (15 cases) MAT groups. The patients were assessed preoperatively and at the 2-year follow-up. Results: In the medial MAT group, the International Knee Documentation Committee, Lysholm, Lysholm instability, and Tegner scores improved significantly at the 2-year follow-up, and there were also significant improvements in the anterior drawer, Lachman, and pivot-shift tests. In the lateral MAT group, the Lysholm and Tegner scores improved significantly at the 2-year follow-up, as had the anterior drawer and Lachman tests but not the pivot-shift test. The medial MAT group showed significant improvement in side-to-side difference on Telos stress radiographs, from 6.5 mm (preoperatively) to 3.6 mm (2-year follow-up) (P = .001), while the lateral MAT group showed no significant change. There was no progression of arthritis in either group. Conclusion: Medial MAT improved not only anteroposterior stability but also rotational stability in the meniscus-deficient ACL-reconstructed knee. Lateral MAT showed improvements in the anterior drawer and Lachman tests but not in the pivot-shift test or side-to-side difference on Telos stress radiographs in meniscus-deficient ACL-reconstructed knees. Instability and pain are indications for MAT in meniscus-deficient ACL-reconstructed knees.

Patellar Malalignment Is Associated With Patellofemoral Lesions and Cartilage Relaxation Times After Hamstring Autograft Anterior Cruciate Ligament Reconstruction

Background: There is growing evidence suggesting a link between patellofemoral joint (PFJ) osteoarthritis in anterior cruciate ligament (ACL)–reconstructed knees and altered joint alignment. Purpose: To determine whether patellar alignment differs between participants with and without ACL reconstruction (ACLR) and to identify possible associations between patellar alignment and PFJ osteoarthritis features over 3 years. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 37 participants with ACLR (sex, 23 male; mean ± SD age, 28.1 ± 7.4 years) and 20 healthy controls (13 male; 30.4 ± 4.8 years) participated. Patients underwent magnetic resonance imaging: (1) sagittal T2-weighted fat-saturated fast spin echo images to calculate patellar alignment, (2) sagittal 3-dimensional intermediate-weighted fast spin echo Cube sequence for clinical morphological grading (modified Whole-Organ Magnetic Resonance Imaging Score [WORMS]), and (3) sagittal combined T1ρ/T2 mapping sequence for performing voxel-based relaxometry. Patellar alignment of the ACLR knees were assessed at 6 months (baseline). One-way analysis of variance was used to compare patellar alignment among the ACLR (at 6 months), contralateral, and control knees. Within the ACLR group, a logistic regression model was used to identify if patellar alignment measures at baseline were risk factors for worsening of PFJ structural changes over 3 years. Statistical parametric mapping was used to evaluate the longitudinal associations between patellar alignment and cartilage relaxation times at 3 years. Results: When compared with control knees, ACLR knees exhibited a laterally and anteriorly displaced patella (P = .045 and P = .041), less flexion (P = .031), and less lateral spin (P = .012). Furthermore, excessive lateral displacement was a significant predictor of worsening of WORMS (P = .050). Lateral displacement was positively correlated with increased T1ρ and T2 in the patellar and trochlear cartilage at 3 years. Patellar lateral spin revealed similar negative findings. Conclusion: Participants with ACLR exhibited a laterally and anteriorly displaced patella, less flexion, and less lateral spin when compared with healthy controls. Excessive patellar lateral displacement was the strongest predictor to the development of PFJ osteoarthritis features longitudinally.

Effect of rocker-sole footwear on knee joint biomechanics while walking in people with ACL-reconstructed knees: a cross-sectional biomechanical study

Background: Reinjury has occurred at a high rate after anterior cruciate ligament (ACL) reconstruction. Low knee flexion angles and high peak posterior ground reaction forces in landing tasks increase ACL loading. Some studies reported that rocker-sole shoes increased knee flexion angle in the early stance phase of the gait. The aim of this study was to investigate the biomechanics of walking with a custom-made heel-to-toe rocker shoe design, with special attention to the sagittal knee joint kinematics of patients after ACL reconstruction. Methods: This study examined 10 male participants with ACL-reconstruction participants. Three-dimensional gait analysis was performed under two conditions of level walking that were tested in random order using either modified footwear adapted with a heel-to-toe rocker sole or baseline footwear with a flat sole. The knee flexion angle at initial foot contact with the ground, average knee flexion angle from heel strike to 25% stance phase, and first peak knee flexion angle were compared across footwear conditions. Results: Walking with the heel-to-toe rocker shoes increased the knee flexion angle at the early stance phase of the gait cycle when compared with the baseline footwear. Conclusions: Rocker-shoe intervention was found to have potential as a rehabilitation tool to modify gait patterns in the sagittal plane of people with ACL-reconstructed knees and may protect against high reinjury rates. Further research is required to evaluate whether prolonged wear of rocker-sole shoes can modify lower extremity biomechanics of participants who have undergone ACL reconstruction. Level of Evidence: Level II.

Does ACL-reconstruction Lead To Higher Use Of Neural Resources To Prepare &amp; Initiate Challenging Jump-landings?

Increased cortical motor planning has been suggested to compensate the loss of mechanoreceptors after anterior cruciate ligament (ACL) injury in simple motor tasks. PURPOSE: To investigate the cortical processes associated with more sports- and injury-related movements. METHODS: Ten males with ACL-reconstructed knee (28±4 yrs., 25±3 kg/m2, 63±35 months since surgery; ACLR) and 17 knee-injury free controls (28±4 yrs., 26±3 kg/m2; all males) completed 70 counter-movement jumps with single-leg landings on a pressure plate. Pre-planned (landing leg shown before take-off; PP) and non-pre-planned (visual cue during flight, 360 ms prior ground contact; NPP) landings (35 each) were performed in random order. Movement-related cortical potentials (MRCPs) were analysed to quantify the neural involvement needed to initiate the jump (higher negative potentials indicate more motor planning) using electroencephalography. The mean activity was calculated for fronto-central (FC1, FC2) and central electrodes (C3, C4, CZ) in three successive epochs prior to movement onset (acceleration sensor): Early (−1.500 to −1.000 ms; RP1), late readiness potential (−1.000 to −500 ms; RP2) and negative slope (−500 to 0 ms/movement onset; NS). RESULTS: In both groups, MRCPs occured at CZ only. A 3 x 2 ANOVA revealed a main effect for a significant increase of negativity (ACLR: F(16)=36, p<0.001, eta=0.8; controls: F(9)=22, p<0.001, eta=0.6) across the three epochs (ACLRPP: RP1:-0.8, RP2:-1.8, NS:-5.8 μV, p<0.01; ACLRNPP: RP1:-0.9, RP2:-3.2, NS:-8 μV, p<0.01; controlsPP: RP1:-0.2, RP2:-1.8, NS:-5.9 μV, p<0.01; controlsNPP: RP1:-0.2, RP2:-1.1, NS:-4.3 μV, p<0.01). Between groups, no significant effects were found for time (F(26)=0.2, p=0.9), landing condition (F(26)=1.3, p=0.3) nor the interaction of both factors (F(26)=2.0, p=0.2). However, the ACLR-group showed a moderate effect for a higher negativity at all epochs in the NPP condition (d≥0.5). CONCLUSION: Our jump-landing task evoked MRCPs irrespective from group and condition. The trends in our data suggest that ACLR-individuals may use more motor planning resources to initiate a challenging motor task. Research is warranted to elucidate the possible implications of such potential central compensations for injury risk. No funding.

Assessment of Post-Rehabilitation ACL Reconstructed Knees

Background: Understanding objective measures of ACL-reconstructed knee function is important in determining the efficacy of rehabilitation protocols and a patient’s return to activities of daily living and sport activities. Objective: To assess the range of motion (ROM), isokinetic strength (torque) and functional performance measures (hop test) of ACL-reconstructed and ACL-intact knees. Methods: Twelve volunteers (5 females, 7 males) with unilateral ACL injury and reconstruction were given a battery of tests (hop test for distance, knee range of motion, knee extensor isokinetic testing to assess both affected and unaffected lower limb function, flexibility and strength. Main effects and interactions were analyzed by mixed-model repeated measures ANCOVA. Dependent variables included hop test for distance, knee flexion and extension range of motion, and knee extensor isokinetic torque. The independent variables were the intact/reconstructed ACL knee and time from surgery. Sex was the covariate. Results: No statistically significant differences (p&gt;0.05) were found across all dependent variables hop test for distance (P = 0.939), knee flexion (P = 0.576) and extension (P = 0.431) ROM, and knee extensor torque (eccentric P = 0.923 and concentric P = 0.723) for the main effects and interactions of knee (ACL-reconstructed and ACL-intact) and time (0-12 months, 13-24 months, 25-36 months and 37+ months). The covariate, sex, did produce significant differences for the hop test (P &lt; 0.0001) and isokinetic testing (eccentric peak torque P = 0.003 and concentric peak torque P=0.012). Conclusions: Clinicians may consider present rehabilitation protocols to be adequate in developing ROM and isokinetic strength following ACL reconstruction. However, greater improvements in ROM and strength may be achieved over an extended period following ACL reconstruction surgery.

Lateral meniscal slope negatively affects post-operative anterior tibial translation at 1 year after primary anterior cruciate ligament reconstruction.

The aim of this study was to assess the correlation between posterior tibial slope and meniscal slope over postoperative anterior tibial translation during the first 18months after primary anterior cruciate ligament (ACL) reconstruction. The main hypothesis was that PTS and MS would be positively correlated with post-operative ATT-SSD after ACL reconstruction. Patients (28 males and 15 females) with confirmed ACL tears were selected from an in-house registry and included if they were over 16years old, had primary ACL-reconstruction and healthy contralateral knee. Patients meeting one of the following criteria were excluded: previous knee surgeries, intraarticular fractures, associated ligamentous lesions, previous or concomitant meniscectomy or extraarticular procedures. Lateral posterior tibial slope, medial posterior tibial slope, lateral meniscal slope and medial meniscal slope were measured using preoperative MRIs. The side-to-side-difference in anterior tibial translation was evaluated 9-18months postoperatively. Forty-three patients were included, (28 males/15 females; mean age 25 ± 8years). Mean postoperative anterior tibial translation was 1.0 ± 1.1mm at a mean time of 12 ± 1months. Mean slope values were: lateral posterior tibial slope 4.7° ± 2.2°, medial posterior tibial slope 4.0° ± 2.8°, lateral meniscal slope 3.0° ± 2.2° and medial meniscal slope 2.0° ± 2.8°. The anterior tibial translation was significantly correlated with lateral meniscal slope (r = 0.63; p < 0.01). For each 1° increase in lateral meniscal slope, a 0.3mm 95% CI [0.2, 0.4] (p < 0.01) increase in anterior tibial translation was observed. A lateral meniscal slope greater or equal to 4.0° was estimated as optimal threshold for increased risk of abnormal side-to-side difference in postoperative anterior tibial translation (≥ 1.2mm). The lateral meniscal slope was positively correlated to side-to-side difference in anterior tibial translation after primary ACL reconstruction. A lateral meniscal slope greater or equal to 4.0° was detected as threshold for an increased risk of abnormal side-to-side difference in postoperative anterior tibial translation in patients who underwent primary ACL reconstruction. This confirms that soft tissue slopes have an impact on the outcomes after reconstructive surgery. Level of evidence III.

Unrepaired lateral meniscus tears lead to remaining pivot-shift in ACL-reconstructed knees.

To compare the postoperative rotatory knee laxity between ACL-reconstructed knees with different meniscus treatments using an electromagnetic pivot-shift measurement. Forty-six patients with unilateral ACL reconstructions were enrolled (21 males/25 females, 25 ± 12 y.o.). Concomitant meniscus tears, if any, were repaired whenever possible during primary ACL reconstruction. At 1 year postoperatively, pivot-shift test was performed under anaesthesia during screw removal surgery and quantitatively evaluated by tibial acceleration using an electromagnetic system. The acceleration was compared between ACL-reconstructed knees with different meniscal treatments: intact, repaired and unrepaired. A concomitant meniscus tear was found in 28 knees preoperatively: lateral tears in 11 knees, medial tears in 11 knees and both medial and lateral tears in 6 knees. Postoperatively, 19 ACL-reconstructed knees had a repaired meniscus for either medial, lateral or bilateral menisci tears, and 18 knees had intact menisci pre- and post-operatively. Meanwhile, nine lateral meniscus tears were irreparable and treated by partial meniscectomy or left in situ. ACL-reconstructed knees with unrepaired lateral menisci had significantly larger pivot-shift acceleration (0.9 ± 0.7m/s2) than those with intact menisci (0.5 ± 0.2m/s2, p < 0.05), whereas rotatory knee laxity was similar between the knees with fully repaired menisci (0.6 ± 0.3m/s2) and intact menisci (n.s.). An unrepaired lateral meniscus tear in an ACL-reconstructed knee could lead to remaining pivot-shift postoperatively. A concomitant meniscus tear should be repaired during ACL reconstruction to restore normal rotational laxity. Therapeutic Study, Level III.

Early chondral damages following meniscus repairs with anterior cruciate ligament reconstructions

Purpose: Early chondral damages following the meniscal repair with anterior cruciate ligament (ACL) reconstruction is unclear. The purpose of this study was to evaluate the zone-specific chondral damages after arthroscopic meniscus repair concomitant with ACL reconstruction. Methods: This study included 42 patients that underwent anatomic double-bundle ACL reconstruction. A second-look arthroscopy was performed at a mean of 16 months postoperatively. We divided the patients into two groups: group A with intact meniscus (22 knees) and group M with meniscus repair (20 knees). No significant difference was observed in patient demographics (Table 1). The surface of knee articular cartilage was divided into 40 sub-compartments as shown in Figure 1. Chondral damages were evaluated arthroscopically in the 40 sub-compartments using International Cartilage Repair Society (ICRS) classification. The same score, as evaluated in the ICRS grade, was given to the sub-compartment. The sub-compartment score was compared between two groups. Clinical outcomes at the final follow-up (average, 30 months) were compared between two groups. Results: The average sub-compartment score at reconstruction in both groups was shown in Figure 2. Significant worsening was noted at the 5 sub-compartments located in the central part of the medial tibiofemoral compartment in group M. The average sub-compartment score at second-look arthroscopy in both groups was shown in Figure 3. Significant worsening was also observed at 9 sub-compartments located in the central part of patella and bilateral tibiofemoral compartment in group M. All clinical scores at the final follow-up were lower in group M than in group A (P > 0.05, Table 2). The overall success rate for meniscus repairs was 89% (25 of 28 menisci) at second-look arthroscopy. Conclusions: We evaluated cartilage status after meniscus repair with ACL reconstruction using second-look arthroscopy. The progression of chondral damages could not be prevented by meniscus repair with ACL reconstruction to the degree of isolated ACL reconstruction. Progression of post-traumatic chondral damages may be faster in patients who underwent ACL reconstruction and meniscus repair than in ACL-reconstructed knees with intact menisci.View Large Image Figure ViewerDownload Hi-res image Download (PPT)View Large Image Figure ViewerDownload Hi-res image Download (PPT)View Large Image Figure ViewerDownload Hi-res image Download (PPT)View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Individuals With an Anterior Cruciate Ligament–Reconstructed Knee Display Atypical Whole Body Movement Strategies but Normal Knee Robustness During Side-Hop Landings: A Finite Helical Axis Analysis

Background: Atypical knee joint biomechanics after anterior cruciate ligament reconstruction (ACLR) are common. It is, however, unclear whether knee robustness (ability to tolerate perturbation and maintain joint configuration) and whole body movement strategies are compromised after ACLR. Purpose: To investigate landing control after ACLR with regard to dynamic knee robustness and whole body movement strategies during sports-mimicking side hops, and to evaluate functional performance of hop tests and knee strength. Study Design: Controlled laboratory study. Methods: An 8-camera motion capture system and 2 synchronized force plates were used to calculate joint angles and moments during standardized rebound side-hop landings performed by 32 individuals with an ACL-reconstructed knee (ACLR group; median, 16.0 months after reconstruction with hamstring tendon graft [interquartile range, 35.2 months]) and 32 matched asymptomatic controls (CTRL). Dynamic knee robustness was quantified using a finite helical axis approach, providing discrete values quantifying divergence of knee joint movements from flexion-extension (higher relative frontal and/or transverse plane motion equaled lower robustness) during momentary helical rotation intervals of 10°. Multivariate analyses of movement strategies included trunk, hip, and knee angles at initial contact and during landing and hip and knee peak moments during landing, comparing ACLR and CTRL, as well as legs within groups. Results: Knee robustness was lower for the first 10° motion interval after initial contact and then successively stabilized for both groups and legs. When landing with the injured leg, the ACLR group, as compared with the contralateral leg and/or CTRL, demonstrated significantly greater flexion of the trunk, hip, and knee; greater hip flexion moment; less knee flexion moment; and smaller angle but greater moment of knee internal rotation. The ACLR group also had lower but acceptable hop and strength performances (ratios to noninjured leg >90%) except for knee flexion strength (12% deficit). Conclusion: Knee robustness was not affected by ACLR during side-hop landings, but alterations in movement strategies were seen for the trunk, hip, and knee, as well as long-term deficits in knee flexion strength. Clinical Relevance: Knee robustness is lowest immediately after landing for both the ACLR group and the CTRL and should be targeted in training to reduce knee injury risk. Assessment of movement strategies during side-hop landings after ACLR should consider a whole body approach.

Patient‐Reported Outcomes One to Five Years After Anterior Cruciate Ligament Reconstruction: The Effect of Combined Injury and Associations With Osteoarthritis Features Defined on Magnetic Resonance Imaging

Persistent symptoms and poor quality of life (QoL) are common following anterior cruciate ligament reconstruction (ACLR). We aimed to determine the influence of a combined ACL injury (i.e., concomitant meniscectomy and/or arthroscopic chondral defect at the time of ACLR and/or secondary injury/surgery to ACLR knee) and cartilage defects defined on magnetic resonance imaging (MRI), bone marrow lesions (BMLs), and meniscal lesions on patient-reported outcomes 1 to 5 years after ACLR. A total of 80 participants (50 men; mean ± SD age 32 ± 14 years) completed the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC) questionnaires as well as a 3T MRI assessment at 1 and 5 years after ACLR. Median patient-reported outcome scores were compared between isolated and combined ACL injuries and with published normative values. Using multivariate regression, we evaluated the association between compartment-specific MRI cartilage, BMLs, and meniscal lesions and patient-reported outcomes at 1 and 5 years. Individuals with a combined injury had significantly worse scores in the KOOS subscale of function in sport and recreation (KOOS sport/rec) and in the IKDC questionnaire at 1 year, and worse scores in the KOOS subscales of pain (KOOS pain), symptoms (KOOS symptoms), and QoL (KOOS QoL) and in the IKDC questionnaire at 5 years compared to those with an isolated injury. Although no feature on MRI was associated with patient-reported outcomes cross-sectionally at 1 year, patellofemoral cartilage defects at 1 year were significantly associated with worse 5-year KOOS symptoms (β = -9.79, 95% confidence interval [95% CI] -16.67, -2.91), KOOS sport/rec (β = -7.94, 95% CI -15.27, -0.61), KOOS QoL (β = -8.29, 95% CI -15.28, -1.29), and IKDC (β = -4.79, 95% CI -9.34, -0.24) scores. Patellofemoral cartilage defects at 5 years were also significantly associated with worse 5-year KOOS symptoms (β = -6.86, 95% CI -13.49, -0.24) and KOOS QoL (β = -11.71, 95% CI -19.08, -4.33) scores. Combined injury and patellofemoral cartilage defects shown on MRI are associated with poorer long-term outcomes. Clinicians should be vigilant and aware of individuals with these injuries, as such individuals may benefit from targeted interventions to improve QoL and optimize symptoms.

Anatomical ACL Reconstruction can Restore the Natural Knee Kinematics than Isometric ACL Reconstruction During the Stance Phase of Walking

The attachment locations of anterior cruciate ligament (ACL) grafts during reconstruction have been reported to influence knee joint function. However, there are controversial opinions on femoral ACL attachment locations for restoring normal knee kinematics. The knee stability and ACL force by different ACL attachment locations could be predicted using the musculoskeletal model simulation. The objectives of this study are to develop a detailed musculoskeletal knee model and to quantify the effect of ACL graft attachment locations on knee kinematics and graft force. Five normal subjects walked at a self-selected speed, and motion data were captured. A detailed knee model including 14 ligaments was developed for dynamics simulation using cadaveric specimen data, which were previously published and are open to public access. The ACL bundles of the model were removed and replaced with ACL grafts to develop anatomical and isometric ACL-reconstructed knee models; the femoral anatomical footprint and isometric locations were used, respectively. After the knee models were embedded in a full-body template model from the AnyBody Managed Model Repository, the full-body musculoskeletal model was simulated using the measured gait data. The isometric reconstruction model had significantly large anterior translation and internal rotation than the intact and anatomical reconstruction model. The average differences between the isometric reconstruction and intact models were 4.5 mm and 3.0° for tibial anterior translation and internal rotation, respectively. The ACL tensional force in the isometric reconstruction model was significantly lower than that in the intact model. Anatomical reconstruction could closely restore the normal knee kinematics.

Proprioceptive and Functional Outcome of the Knee in Arthroscopic Anterior Cruciate Ligament Reconstruction of a Preserved Remnant Tissue

Background: Injury to the ACL(Anterior Cruciate Ligament) not only causes mechanical instabilitybut also leads to functional deficit in the form of diminished proprioception of the knee joint. This studyanalyzes and reviews our understanding of the sensory element of ACL deficiency, with specific referenceto proprioception as an important component of functional knee stability.Method: 100 patients who underwent ACL reconstruction surgery and completed Simple and EffectiveRehabilitation Protocol(SERP) with minimum duration of 2 years from surgery to follow up, were allassessed for proprioception, stability and functional outcome of the reconstructed knee. They were assessedby the knee joint position sense, single leg hop test for both the normal and reconstructed knee and KOOSquestionnaire respectively.Result: Chi square table value for 1degree freedom at 0.05 was 3.84, hence the calculated Chi square valuesof proprioception knee in supine lying, proprioception knee in standing and single leg hop are less than tablevalue of the accepted hypothesis which concludes that, there is no significant difference between the scoresof selected outcome variables among reconstructed knee and normal knee subjects. The calculated paired‘t’and ‘t’ table value with respect to the functional outcome of knee in operated and normal subjects was 6.53and 2.66 respectively at 0.005 level.Conclusion: There was no significant difference of Proprioception between the scores of selected outcomevariables among reconstructed knee and normal knee in supine lying, standing and single leg hop. But itshows that there is significant difference of 2.66 at 0.005 level between reconstructed knee and normal kneegroups with respect to the functional outcome of knee after two years of follow-up in ACL reconstructedknees

Patients With Abnormal Limb Kinetics at 6 Months After Anterior Cruciate Ligament Reconstruction Have an Increased Risk of Persistent Medial Meniscal Abnormality at 3 Years.

Background:Several reports have shown that altered biomechanics after anterior cruciate ligament reconstruction (ACLR) are associated with the development of posttraumatic osteoarthritis. However, it is not fully understood whether altered biomechanics are associated with meniscal changes after ACLR.Purpose:To investigate changes in gait and landing biomechanics over a 3-year period and their correlation with meniscal matrix alterations present before and after ACLR through use of magnetic resonance T1ρ/T2 mapping, which can allow detection of early meniscal degeneration.Study Design:Cohort study; Level of evidence, 2.Methods:A total of 36 patients with ACLR and 14 healthy controls were included in this study. All patients underwent magnetic resonance imaging and biomechanical analysis during gait of the injured knee and contralateral knee preoperatively and at 6 months, 1 year, 2 years, and 3 years after ACLR, as well as biomechanical analysis during drop-landing from 6 months to 3 years postoperatively. To evaluate biochemical changes of the mensical matrix, T1ρ/T2 relaxation times of the meniscus were calculated.Results:Mean T1ρ/T2 values of ACLR knees were significantly higher than values in the contralateral and control knees in the posterior lateral and medial horns up to 1 year after surgery; however, the differences were not seen at 3 years after surgery. The ACLR knee exhibited significantly lower peak knee flexion moment and angle during gait at 6 months compared with baseline and continued to decrease until 3 years. The ACLR knee exhibited significantly lower peak vertical ground-reaction force and peak knee flexion moment and angle during landing at 6 months. However, the differences were no longer present at 3 years. Biomechanics at 6 months had significant correlations with changes of mean T1ρ/T2 values in the medial posterior horn from 6 months to 3 years after ACLR.Conclusion:Although mean T1ρ/T2 values of meniscus seen before ACLR improved after 3 years, approximately 30% of patients with ACLR did not show decreases from 6 months to 3 years. Patients with abnormal lower limb kinetics of the ACLR knee at 6 months showed less recovery in the medial posterior horn from 6 months to 3 years, suggesting that biomechanical parameters during the early stage of recovery might be potential biomarkers for predicting persistent medial meniscal abnormality after ACLR.

ACL and Posterolateral Corner Injuries.

The importance of the posterolateral corner (PLC) with respect to knee stability, particularly in the setting of anterior cruciate ligament (ACL) deficiency, has become more apparent in recent years. The purposes of this article are to review the current concepts of PLC injuries and to address their role in the ACL-deficient and ACL-reconstructed knee. Recent literature demonstrates that a single staged, combined reconstruction is optimal. Studies further provide more thorough insight into avoidance of tunnel collision during the multiligament reconstruction. In total, reconstruction procedures have demonstrated successful outcomes in over 90% of patients. In summary, we report that in the setting of suspected concomitant PLC and ACL injury, it is essential to address both injuries; appreciating the local anatomy, diagnostic modalities, and surgical techniques are each crucial to achieving desirable clinical outcomes.

Anterior cruciate ligament repair versus reconstruction: A kinematic analysis

BackgroundThe purpose of this study was to compare the biomechanical properties of an anterior cruciate ligament (ACL) anatomic repair of a true femoral avulsion to an anatomic ACL reconstruction. It was hypothesized that the ACL repair and ACL reconstruction would have comparable biomechanical behavior when compared to the native knee. MethodsTen paired fresh-frozen cadaveric knees (n = 20) were used to investigate knee kinematics when an anterior drawer force, varus, valgus, internal, and external rotational moment were applied at 0, 15, 30, 45, 60, and 90 degrees of flexion. Displacement and rotation were recorded in the following conditions: ACL-intact, ACL-deficient, and ACL-repaired vs reconstructed. ResultsSectioning of the ACL significantly increased anterior tibial translation (0°, 15°, 30° and 45°) compared to the intact state. The mean anterior displacement difference from intact was lower in the ACL-repaired knees compared to reconstructed knees at 30° and 90°. There were no significant differences between conditions in varus, valgus, internal, or external rotations. ConclusionACL repair and ACL reconstruction procedures restored knee anterior tibial translation in matched paired specimens. There were no differences in valgus, varus, internal, or external rotation. Although, ACL-repaired knees (avulsion model) demonstrated less anterior tibial translation when compared to ACL-reconstructed knees, this difference was less than one millimeter. Based on the findings of this study, repair and reconstruction procedures both restored anterior tibial translation in matched-pair specimens. This suggests that the initial functionality of both techniques is similar and that further clinical studies are needed to compare the long-term stability.

In vivo gait kinematics of the knee after anatomical and non-anatomical single-bundle anterior cruciate ligament reconstruction-a prospective study.

The factors that influence functions of knees after anterior cruciate ligament reconstruction (ACLR) still remains uncertain. The functional restoration of knees after ACLR can be reflected on gait kinematics restoration. The purpose of this study was to evaluate the gait kinematics and clinical outcomes of knees after anatomical and non-anatomical single-bundle ACLR during level walking. Thirty-four patients with unilateral primary single-bundle ACLR and 18 healthy people were recruited. Patients were divided into anatomical reconstruction group (AR group; n=13) and non-anatomical reconstruction group (Non-AR group; n=21) according to Bernard Quadrant method. The ACL graft orientations on coronal and sagittal planes were measured on 3D models from medical images. The 6 degrees of freedom (DOF) kinematics of knees and range of motion (ROM) of 6 DOF kinematics were measured with a portable optical tracking system. The comparison of 6 DOF kinematics and ROM of 6 DOF kinematics were performed between the ACLR knees and contralateral knees. The following assessments were also performed including clinical examination, KT-2000 arthrometer measurement, International Knee Documentation Committee (IKDC) and Lysholm scores. All patients reached a minimum follow-up of 6 months (10±4 months). For AR group and Non-AR group, no statistically significant differences were observed in gait kinematics between the ACLR knees and contralateral knees. No statistically significant differences between the ACLR knees and contralateral knees were observed in terms of ROM of 6 DOF kinematics in AR group. However, in Non-AR group, the ACLR knees exhibited significant ROM of anterior-posterior translation by approximately 0.5 cm than contralateral knees (P=0.0080). No statistically significant differences between the two groups were observed regarding IKDC subjective score, Lysholm score and KT-2000 arthrometer test. The anatomical ACLR can restore close to normal gait kinematics and ROM of 6 DOF kinematics compared with non-anatomical ACLR. The ACL graft after anatomical ACLR simulated native ACL fibers to function in terms of graft orientation.

The Role of High Tibial Osteotomy in ACL Reconstruction in Knees with Coronal and Sagittal Plane Deformity.

Coronal and sagittal malalignment in the setting of anterior cruciate ligament (ACL) deficiency alters knee biomechanics and is shown to increase stress and strain on the native ACL and on the ACL graft during reconstruction. The purpose of this review was to determine the role and indications of high tibial osteotomy to correct coronal and/or sagittal plane malalignment with ACL reconstruction. Recent literature illustrates that an increase in varus malalignment and increased posterior tibial slope increases the biomechanical stress that is seen in a native or reconstructed ACL graft. It has been proposed to correct the sagittal and coronal malalignment by employing a high tibial osteotomy either prior to or at the time of ACL reconstruction to correct these deformities and to decrease the stress placed on the reconstructed ACL graft. The use of high tibial osteotomy for deformity correction creates a more stable knee for ACL reconstruction and has been shown to have good outcomes with regard to post-operative pain, stability, satisfaction scores, and function.