ACL-reconstructed Knees Research Articles

Sequential analysis of three-dimensional tibiofemoral relationship through anatomic anterior cruciate ligament reconstruction with gravity-assisted radiographic technique in prone position

Background/objectivesIt is important to restore the tibiofemoral relationship as well as the anterior knee laxity for more successful anterior cruciate ligament (ACL) reconstruction, since a residual abnormality in the tibiofemoral relationship would lead an abnormal stress on the articular cartilages/menisci and consequently increase the risk of osteoarthritis in the future. This study aimed to sequentially clarify the three-dimensional tibiofemoral relationship before and after anatomic anterior cruciate ligament (ACL) reconstruction under an anterior tibial load with a gravity-assisted radiographic technique in the prone position. MethodsFifteen patients with unilateral ACL injury participated in the study. Anatomic triple-bundle ACL reconstruction was performed using semitendinosus tendon autografts. During the computed tomography scans that were performed preoperatively, and those performed at 3 weeks and at 6 months postoperatively, the patients lay in the prone position with the knee flexed at 15°, wherein the calf weight could exert an anterior drawer force on the tibia due to gravity. Three-dimensional the tibial position relative to the femur were evaluated for each time point, followed by calculation of side-to-side differences in the parameters between the ACL-deficient/ACL-reconstructed knees and the contralateral intact knees. Seven healthy volunteers were enrolled in the control group and the side-to-side differences (right minus left) in these parameters were calculated. ResultsThe tibia in the ACL-deficient knee was located anteriorly by 3.5 ± 1.1 mm and rotated internally by 2.4° ± 2.3°; these values were significantly larger than the corresponding values of −0.2 ± 1.5 mm and 0.1° ± 2.2° in the control group. However, at 3 weeks postoperatively, the tibia in the ACL-reconstructed knee was over-constrained as compared to that in the control group; it was located posteriorly by 2.5 ± 1.4 mm and rotated externally by 3.4° ± 3.4°. At 6 months postoperatively, no significant difference was observed in the tibial displacements/rotations between the patient and control groups. The side-to-side difference in the anterior knee laxity at the manual maximum anterior load was 0.1 ± 1.2 mm at 6 months postoperatively, with a significant improvement over the preoperative value of 7.4 ± 2.5 mm. ConclusionsAnatomic ACL reconstruction could restore not only the normal anterior knee laxity, but also the normal tibiofemoral relationship even under an anterior tibial load.

The effects of patellar tendon vibration on quadriceps strength in anterior cruciate ligament reconstructed knees

ObjectivesTo examine the immediate effects of prolonged patellar tendon vibration on quadriceps strength in anterior cruciate ligament reconstructed (ACLR) knees with bone-patellar tendon-bone (BTB) grafts and non-BTB grafts, and healthy control knees. DesignPretest-posttest design. SettingLaboratory. ParticipantsYoung adult participants were stratified into one of three groups: non-BTB graft (n = 25), BTB graft (n = 26), and controls without ACLR (n = 21). Main outcome measuresMaximum voluntary isometric contraction (MVIC) knee extension torque was measured at baseline and following a 20-min vibration intervention applied locally to the patellar tendon. ResultsOur findings suggest there was no difference in the effects of vibration on knee extension torque between the three groups. Knee extension torque significantly increased (effect size = 0.52 [0.18 to 0.81]) from baseline to post-vibration across all three groups (0.30 ± 0.26 Nm/kg, 21.8 ± 20.0%). Both ACLR groups demonstrated significantly lower knee extension torque compared the control group. ConclusionsThe vibration intervention had a net excitatory effect on quadriceps strength in all three groups and there were no differences in the magnitude of change between the three groups. Vibration could become a useful tool for enhancing quadriceps strength in ACLR and healthy knees.

No difference in postoperative rotational laxity after ACL reconstruction in patients with and without anterolateral capsule injury: quantitative evaluation of the pivot-shift test at 1-year follow-up.

To compare rotational laxity in anterior cruciate ligament (ACL)-reconstructed knees retrospectively with and without concomitant anterolateral capsule (ALC) injury confirmed by magnetic resonance imaging (MRI) prior to ACL reconstruction. Sixty-two ACL-reconstructed knees (26 men, 36 women; median age 20 (range 13-59)) were included. Pivot-shift test was performed before ACL reconstruction and 1year postoperatively under anesthesia with both clinical grading and quantitative measurement simultaneously. Clinical grading was determined according to the International Knee Documentation Committee (IKDC) criteria (none, glide, clunk, or gross), and an electromagnetic measurement system was used to provide tibial acceleration as a quantitative parameter. The resence of concomitant ALC injury was confirmed retrospectively by MRI. The pivot-shift test was compared between ACL-reconstructed knees with and without ALC injury test for clinical grading and the independent t test for quantitative evaluation. ALC injury was identified in 26 of 62 (42%) knees. Before ACL reconstruction, there was no difference in the pivot-shift test results between the ACL-deficient knees with and without ALC injury in IKDC grading (n.s.) or tibial acceleration (1.1 ± 0.7m/s2 and 1.4 ± 1.1m/s2, respectively, n.s.). At 1year postoperatively, no difference was observed between groups (IKDC, p = 0.90; tibial acceleration, 0.6 ± 0.3m/s2 and 0.8 ± 0.6m/s2, n.s.). Concomitant ALC injury at the time of ACL injury had no effect on the rotational laxity of the knee in the postoperative course after ACL reconstruction. Therefore, additional treatment for ALC injury may not be warranted. IV.

Tibiofemoral joint structural change from 2.5 to 4.5\u2009years following ACL reconstruction with and without combined meniscal pathology

BackgroundPeople who have had anterior cruciate ligament reconstruction (ACLR) are at a high risk of developing tibiofemoral joint (TFJ) osteoarthritis (OA), with concomitant meniscal injury elevating this risk. This study aimed to investigate OA-related morphological change over 2 years in the TFJ among individuals who have undergone ACLR with or without concomitant meniscal pathology and in healthy controls. A secondary aim was to examine associations of baseline TFJ cartilage defects and bone marrow lesions (BML) scores with tibial cartilage volume change in ACLR groups.MethodsFifty seven ACLR participants aged 18–40 years (32 isolated ACLR, 25 combined meniscal pathology) underwent knee magnetic resonance imaging (MRI) 2.5 and 4.5 years post-surgery. Nine healthy controls underwent knee MRI at the ~ 2-year intervals. Tibial cartilage volume, TFJ cartilage defects and BMLs were assessed from MRI.ResultsFor both ACLR groups, medial and lateral tibial cartilage volume increased over 2 years (P < 0.05). Isolated ACLR group had greater annual percentage increase in lateral tibial cartilage volume compared with controls and with the combined group (P = 0.03). Cartilage defects remained unchanged across groups. Both ACLR groups showed more lateral tibia BML regression compared with controls (P = 0.04). Baseline cartilage defects score was positively associated with cartilage volume increase at lateral tibia (P = 0.002) while baseline BMLs score was inversely related to medial tibia cartilage volume increase (P = 0.001) in the pooled ACLR group.ConclusionsTibial cartilage hypertrophy was apparent in ACLR knees from 2.5 to 4.5 years post-surgery and was partly dependent upon meniscal status together with the nature and location of the underlying pathology at baseline. Magnitude and direction of change in joint pathologies (i.e., cartilage defects, BMLs) were less predictable and either remained stable or improved over follow-up.

Increases in Joint Laxity After Anterior Cruciate Ligament Reconstruction Are Associated With Sagittal Biomechanical Asymmetry

To investigate the longitudinal changes in landing mechanics and knee kinematics for patients both before and 3years after anterior cruciate ligament reconstruction (ACLR) and to investigate the association between changes in landing mechanics and magnetic resonance knee kinematics. Thirty-one ACLR patients were included in the study. All patients underwent magnetic resonance imaging and biomechanical analysis of a drop-landing task using the injured knee and contralateral knee preoperatively and at 6months and 3years after ACLR. For evaluations of knee joint anteroposterior laxity, tibial position was calculated using quantitative loaded magnetic resonance methods. The ACLR knee exhibited a significantly lower peak vertical ground reaction force and peak external knee flexion moment and angle at 6months compared with the contralateral knee; however, the differences were resolved at 3years. Tibial position was significantly more anterior on the injured side, and the side-to-side difference (SSD) in tibial position exhibited a significant increase from 6months to 3years. Among ACLR knees, a greater SSD in peak knee flexion moment at 6months was associated with an increase in the SSD in anterior tibial translation from 6months to 3years. Although landing mechanics and clinical outcomes recovered in patients with ACLR in this study, anteroposterior translation failed to be restored at 3years after surgery. In addition, patients who have low knee flexion moments in early stages could have greater anteroposterior laxity. Because of the adverse consequences of abnormal knee kinetics on anterior laxity after ACLR, efforts to improve knee movement patterns should be initiated.

Return To Play Testing In Individuals With ACL-Reconstructed Knees: Does Timing Of The Assessment Matter?

Return To Play Testing In Individuals With ACL-Reconstructed Knees: Does Timing Of The Assessment Matter?

Arthroscopic centralization restores residual knee laxity in ACL-reconstructed knee with a lateral meniscus defect.

The aim of this study was to evaluate the effects of knee biomechanics with an irreparable lateral meniscus defect using the centralization capsular meniscus support procedure in the setting of the ACL-reconstructed knee in a porcine model. The hypothesis is the arthroscopic centralization will decrease the laxity and rotation of the ACL-reconstructed knee. Twelve fresh-frozen porcine knees were tested using a robotic testing system under the following loading conditions: (a) an 89.0N anterior tibial load; (b) 4.0Nm internal and external rotational torques. Anatomic single-bundle ACL reconstruction with a 7mm-diameter bovine extensor tendon graft was performed. A massive, middle segment, lateral meniscus defect was created via arthroscopy, and arthroscopic centralization was performed with a 1.4mm anchor with a #2 suture. The LM states with ACL reconstruction evaluated were: intact, massive middle segment defect and with the lateral meniscus centralization procedure. The rotation of the ACL reconstructed knee with the lateral meniscus defect was significantly higher than with the centralized lateral meniscus under an external rotational torque at 30° of knee flexion, and under an internal rotational torque at 30° and 45° of knee flexion. There were no systematic and consistent effects of LM centralization under anterior tibial translation. In this porcine model, the capsular support of middle segment of the lateral meniscus using arthroscopic centralization improved the residual rotational laxity of the ACL-reconstructed knee accompanied with lateral meniscus dysfunction due to massive meniscus defect. This study quantifies the benefit to knee kinematics of arthroscopic centralization by restoring the lateral meniscal function.

Does early reconstruction of the anterior cruciate ligament prevent further meniscal damage? Secondary analysis of randomized controlled trial

Purpose: There is no low-risk-of-bias evidence to support the notion that surgical reconstruction of the anterior cruciate ligament (ACL) lowers the risk of future meniscal damage. Therefore, we investigated the loss of meniscal integrity on knee MRI over 5 years using data from the only randomized controlled trial in the field, comparing rehabilitation plus early ACL reconstruction vs a strategy of rehabilitation with optional delayed ACL reconstruction. Methods: We used longitudinal knee MRI data from 121 young active adults randomized to structured rehabilitation plus early ACL reconstruction (“early reconstruction” arm) or to structured rehabilitation with optional delayed ACL reconstruction (“optional delayed reconstruction” arm) (ISRCTN 84752559). Knee MRIs at baseline (after randomization but before treatment), and at the 5-year follow-up were read paired with knowledge of time sequence by one experienced musculoskeletal radiologist using the Anterior Cruciate Ligament Osteoarthritis Score (ACLOAS). Reader blinding to ACL-reconstructed knees at the 5-year follow-up was not feasible, but the reader was unaware of the specific study questions. Meniscal integrity was determined for all three segments of the medial and lateral meniscus. Worsening of meniscal integrity from baseline to the 5-year follow-up was defined as the occurrence of one or more of the following: i) an incident meniscal tear or progression of a pre-existing meniscal tear to involve another segment ii) incident loss of meniscus substance (due to maceration/destruction or surgical resection) iii) a new finding of status post meniscal repair, or iv) increase in medial or lateral meniscal body extrusion. With this dichotomized outcome, in an intention-to-treat analysis (ITT), we compared frequency of worsening of meniscal integrity on MRI in both treatment arms from baseline to 5 years using a logistic regression model. The model was adjusted for age, sex, and meniscal tears on MRI at baseline. For greater sensitivity and to evaluate severity of meniscal damage at 5 years, we also used a continuous outcome (integrity score) based on the sum of reclassified subregional meniscal grades from the ACLOAS (Table 1). For the integrity score, we used a zero-inflated Poisson regression model to compare severity of meniscal damage in an ITT analysis. This model was adjusted for age, sex, and baseline integrity score. Participants without baseline MRI readings were excluded from the analyses. Analyses were performed on knee level as well as on compartment level. Results: In the early reconstruction arm 62 participants were included, of which one was lost to follow-up. Four of the remaining 61 subjects had missing MRI readings at baseline. As a result, 57 subjects (mean [SD] age 26.6 [5.2] years, 81% men) remained for analysis. In the optional delayed reconstruction arm, 59 subjects (mean [SD] age 25.8 [4.7] years, 66% men) were included without loss to follow-up, with 30 subjects (51%) having had delayed ACL reconstruction within 5 years. Before treatment, the early reconstruction arm had more lateral meniscal damage detected on MRI (26% vs 7%), but medial meniscus damage was similar in both treatment arms (14% vs 15%). After 5 years, 19% of subjects in the early reconstruction arm had worsening of medial meniscal integrity vs 38% in the optional delayed reconstruction arm. For lateral meniscal integrity it was 38% vs 22%, respectively. We found a relative risk (RR) for worsening in meniscal integrity after 5 years on the knee level of 1.29 with a 95% confidence interval (CI) of 0.90-1.85 in the optional delayed reconstruction arm vs the early reconstruction arm. For worsening of medial meniscus integrity the RR was 1.95 (95% CI 1.06-3.57). For lateral meniscus the corresponding RR was 1.01 (95% CI 0.64-1.57). Relatively more subjects with an uninjured medial meniscus at baseline in the optional delayed reconstruction arm had worsening of medial meniscal integrity after 5 years compared to the early reconstruction arm (35% vs 12%). Meniscal worsening per segment is presented in Figure 1. Using meniscal integrity score as outcome, we found a 1.38 higher (severe) mean integrity score in the optional delayed reconstruction arm vs the early reconstruction arm (95% CI 1.07-1.78). For medial meniscus integrity, the corresponding model yielded a 1.80 higher mean score (95% CI 1.02-3.17), and for lateral meniscus integrity 1.04 (95% CI 0.63-1.75). Change in integrity score from baseline to the 5-year follow-up for the medial and the lateral meniscus for each treatment arm, respectively, is detailed in Figure 2. Conclusions: A strategy of early ACL reconstruction may reduce the risk of worsening of medial meniscus integrity following ACL injury. For the lateral meniscus, ACL reconstruction seems neither to be protective nor to increase the risk of future meniscal damage.View Large Image Figure ViewerDownload Hi-res image Download (PPT)View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Quadriceps Torque, Peak Variability and Strength Endurance in Patients after Anterior Cruciate Ligament Reconstruction: Impact of Local Muscle Fatigue

We tested if ACL-reconstructed participants show a decreased quadriceps torque, a lower muscle endurance capacity and a higher peak torque variability compared to unimpaired control participants prior to and following local muscle fatigue. Participants (n = 19, 10 women; 25 ± 5yrs.) with unilateral hamstrings autograft ACL-reconstruction and a matched unimpaired control group were recruited. Participants performed two maximal isometric voluntary force (MIVF) contractions of the knee extensors. In between, standardized local muscle fatigue was induced. ACL-reconstructed knees display a lower peak torque of the knee extensors in comparison to the contralateral limb (3.2 ± .3Nm/kg vs. 3.5 ± .3 Nm/kg). Peak torque variability and fatigue resistance were not affected by local muscle fatigue (p > .05). Participants with ACL-reconstructed knees show a persistent quadriceps muscle dysfunction. This dysfunction and lower limb side asymmetries might be risk factors for ACL re-ruptures.

Peak torque angle of anterior cruciate ligament-reconstructed knee flexor muscles in patients with semitendinosus and gracilis autograft is shifted towards extension regardless of the postoperative duration of supervised physiotherapy.

BackgroundThe observational cohort study investigated whether the flexor muscles peak torque (PT) angle shifting towards extension observed in the involved knee in patients after anterior cruciate ligament reconstruction (ACLR) using semitendinosus and gracilis tendon (STGR) autograft is associated with the postoperative physiotherapy supervision duration.MethodsFrom 230 ACL-reconstructed males, we identified patients after ACLR utilizing STGR autograft and divided them into those who completed supervised physiotherapy <6 months (Group I; n = 77) and those who completed supervised physiotherapy ≥6 months (Group II; n = 66). The mean follow-up time was 6.84 ± 1.47 months. The ACL-reconstructed patients were compared to 98 controls (Group III). Bilateral knee flexor muscle PT measurements were performed. The relative PT at 180°/s (RPT), PT angle at 180°/s, and range of motion at 180°/s were analysed. The RPT limb symmetry index (LSI) was calculated. Tests for dependent samples, one-way analysis of variance, post hoc test, and linear Pearson’s correlation coefficient (r) calculations were performed.ResultsThe shift towards extension was noted when comparing the ACL-reconstructed limb to the uninvolved limb (Group I, p ≤ 0.001; Group II, p ≤ 0.001) and to Group III (p ≤ 0.001), but it was not correlated with physiotherapy supervision duration (r = -0.037, p = 0.662). In ACL-reconstructed patients, there was a moderate association of supervision duration and knee flexor LSI (r = 0.587, p < 0.001).ConclusionsThe ACL-reconstructed knee flexors PT angle shift towards extension was observed regardless of the duration of postoperative physiotherapy supervision. However, the analysis revealed that the duration of supervised physiotherapy positively influenced the RPT and LSI in patients after the ACLR.

Slope-reducing tibial osteotomy decreases ACL-graft forces and anterior tibial translation under axial load.

Posterior tibial slope (PTS) represents an important risk factor for anterior cruciate ligament (ACL) graft failure, as seen in clinical studies. An anterior closing wedge osteotomy for slope reduction was performed to investigate the effect on ACL-graft forces and femoro-tibial kinematics in an ACL-deficient and ACL-reconstructed knee in a biomechanical setup. Ten cadaveric knees with a relatively high native slope (mean ± SD): (slope 10°±1.4°, age 48.2years ± 5.8) were selected based on prior CT measurements. A 10° anterior closing-wedge osteotomy was fixed with an external fixator in the ACL-deficient and ACL-reconstructed knee (quadruple Semi-T/Gracilis-allograft). Each condition was randomly tested with both the native tibial slope and the post-osteotomy reduced slope. Axial loads (200N, 400N), anterior tibial draw (134N), and combined loads were applied to the tibia while mounted on a free moving and rotating X-Y table. Throughout testing, 3D motion tracking captured anterior tibial translation (ATT) and internal tibial rotation (ITR). Change of forces on the reconstructed ACL-graft (via an attached load-cell) were recorded, as well. ATT was significantly decreased after slope reduction in the ACL-deficient knee by 4.3mm ± 3.6 (p < 0.001) at 200N and 6.2mm ± 4.3 (p < 0.001) at 400N of axial load. An increase of ITR of 2.3° ±2.8 (p < 0.001) at 200N and by 4.0° ±4.1 (p < 0.001) at 400N was observed after the osteotomy. In the ACL-reconstructed knee, ACL-graft forces decreased after slope reduction osteotomy by a mean of 14.7N ± 9.8 (p < 0.001) at 200N and 33.8N ± 16.3 (p < 0.001) at 400N axial load, which equaled a relative decrease by a mean of 17.0% (SD ± 9.8%), and 33.1% (SD ± 18.1%), respectively. ATT and ITR were not significantly changed in the ACL-reconstructed knee. Testing of a tibial anterior drawing force in the ACL-deficient knee led to a significantly increased ATT by 2.7mm ± 3.6 (p < 0.001) after the osteotomy. The ACL-reconstructed knee did not show a significant change (n.s.) in ATT after the osteotomy. However, ACL-graft forces detected a significant increase by 13.0N ± 8.3 (p < 0.001) after the osteotomy with a tibial anterior drawer force, whereas the additional axial loading reduced this difference due to the osteotomy (5.3N ± 12.6 (n.s.)). Slope-reducing osteotomy decreased anterior tibial translation in the ACL-deficient and ACL-reconstructed knee under axial load, while internal rotation of the tibia increased in the ACL-deficient status after osteotomy. Especially in ACL revision surgery, the osteotomy protects the reconstructed ACL with significantly lower forces on the graft under axial load.

Coping With Anterior Cruciate Ligament Injury From Childhood to Maturation: A Prospective Case Series of 44 Patients With Mean 8 Years’ Follow-up

Background: There is no consensus regarding the best treatment approach for skeletally immature children with anterior cruciate ligament (ACL) injuries. High-quality studies with long-term follow-up are lacking, and evidence to support decision making is limited. Purpose: To evaluate functional and patient-reported outcome, surgical history, and complications among young adults who sustained an ACL injury before the age of 13 years and were treated with active rehabilitation and the option of delayed ACL reconstruction if needed. Study Design: Case series; Level of evidence, 4. Methods: Forty-six children aged <13 years with a total intrasubstance ACL injury were included. None of these patients had additional injuries that warranted early surgery. At final follow-up at a mean 8 years after the time of injury, 44 patients remained in the study. The same test battery was conducted at baseline, 1 and 2 years, and final follow-up at approximately 18 years of age. The test battery included functional tests (hop tests and isokinetic muscle strength tests of quadriceps and hamstrings), patient-reported outcome measures (including the Knee injury and Osteoarthritis Outcome Score and the International Knee Documentation Committee Subjective Knee Form), and clinical examination. Medical records were reviewed to assess surgical history and complications. Results: At a mean 8 years of follow-up, 24 patients (55%) had undergone ACL reconstruction, and 16 (36%) had undergone meniscal surgery. Quadriceps muscle strength symmetry was >90% for 30 patients (68%). Mean leg symmetry indexes for hop and strength tests were consistently >90%, except for the single-hop test and hamstrings muscle strength for ACL-reconstructed knees. Mean ± SD International Knee Documentation Committee scores were 86.3 ± 13.7 for the ACL-reconstructed knees and 90.6 ± 11.8 for the nonreconstructed knees. At final follow-up, forty patients (91%) remained active in sports, but 29 (66%) restricted their activity level to nonpivoting sports. Conclusion: Active rehabilitation may have a role in treatment of children with ACL injury. Approximately 50% of children may cope well, even to adulthood, without a surgical intervention. The other half may develop instability that warrants ACL reconstruction, and one-third may require meniscal surgery.

Abnormal Biomechanics at 6 Months Are Associated With Cartilage Degeneration at 3 Years After Anterior Cruciate Ligament Reconstruction

To investigate the changes in landing biomechanics over a 3-year period and their correlation with cartilage degenerative changes in the medial tibiofemoral joint of the knee after anterior cruciate ligament reconstruction (ACLR) using magnetic resonance T1ρ mapping. Thirty-one anterior cruciate ligament-injured patients underwent magnetic resonance imaging of the injured knee before ACLR and 3years after ACLR, as well as biomechanical analysis of a drop-landing task at 6months and 3years after ACLR. Sixteen healthy individuals were recruited and underwent knee magnetic resonance imaging and biomechanical assessment during a drop-landing task. T1ρ cartilage relaxation times were calculated for the medial femur and tibia. ACLR patients exhibited increased peak vertical ground reaction force (VGRF), VGRF impulse, peak knee flexion moment (KFM), and KFM impulse from 6months to 3years (P < .001 for each). Although the ACLR knees showed significantly lower peak VGRF and KFM at 6months (P < .001 for both) when compared with the controls, there were no significant differences at 3years. At 3years, ACLR patients showed higher T1ρ values over the medial femur (P < .001) and tibia (P= .012) when compared with their preoperative values and with healthy control values. Within the ACLR group, side-to-side differences in peak VGRF and sagittal knee biomechanics at 6months were associated with increased T1ρ values from baseline to 3years. The results of this longitudinal study show that landing biomechanics are altered after ACLR but biomechanical abnormalities tend to recover at 3years after ACLR. Differences in lower-extremity mechanics during a landing task at 6months may be associated with cartilage degeneration at 3years after anterior cruciate ligament injury and reconstruction. Level II, prospective trial.

Lateral Meniscal Posterior Root Repair With Anterior Cruciate Ligament Reconstruction Better Restores Knee Stability

Background: The effect of lateral meniscal posterior root tear and repair—commonly seen in clinical practice in the setting of anterior cruciate ligament (ACL) reconstruction—is not known. Purpose/Hypothesis: This study evaluated the effect of tear and repair of the lateral meniscal posterior root on the biomechanics of the ACL-reconstructed knee. It was hypothesized that anterior tibial translation would increase under anterior loading and simulated pivot-shift loading with the root tear of the posterior lateral meniscus, while repair of the root tear would reduce it close to the noninjured state. Study Design: Controlled laboratory study. Methods: Thirteen fresh-frozen adult human knees were tested with a robotic testing system under 2 loading conditions: (1) an 89.0-N anterior tibial load applied at full extension and 15°, 30°, 60°, and 90° of knee flexion and (2) a combined 7.0-N·m valgus and 5.0-N·m internal tibial torque (simulated pivot-shift test) applied at full extension and 15° and 30° of knee flexion. The following knee states were tested: intact knee, ACL reconstruction and intact lateral meniscus, ACL reconstruction and lateral meniscal posterior root tear, and ACL reconstruction and lateral meniscal posterior root repair. Results: In the ACL-reconstructed knee, a tear of the lateral meniscal posterior root significantly increased knee laxity under anterior loading by as much as 1 mm. The transosseous pullout suture root repair improved knee stability under anterior tibial and simulated pivot-shift loading. Root repair improved the ACL graft force closer to that of the native ACL under anterior tibial loading. Conclusion: Lateral meniscal posterior root injury further destabilizes the ACL-reconstructed knee, and root repair improves knee stability. Clinical Relevance: This study suggests a rationale for surgical repair of the lateral meniscus, which can restore stability close to that of the premeniscal injury state.

Neuroplastic changes in anterior cruciate ligament reconstruction patients from neuromechanical decoupling.

The purpose of this study was to identify how the brain simultaneously perceives proprioceptive input during joint loading in anterior cruciate ligament reconstruction (ACLR) patients, when compared to healthy controls. Seventeen ACLR patients (ACLR) and seventeen controls (CONT) were tested for the somatosensory cortical activation using electroencephalography (EEG) while measuring knee laxity using a knee arthrometer. The relationship between cortical activation and joint laxity within group was also examined. The ACLR patients had increased cortical activation (36.4%±11.5%) in the somatosensory cortex during early loading (ERD1) to the injured limb compared to the CONT's matched limb (25.3%±13.2%, P=0.013) as well as compared to the noninjured limb (25.1%±14.2%, P=0.001). Higher somatosensory cortical activity during midloading (ERD2) to the ACLR knee positively correlated with knee laxity (mm) during early loading (LAX1, r=0.530), midloading (LAX2, r=0.506), total anterior loading (LAXA, r=0.543), and total antero-posterior loading (LAXT, r=0.501), while the noninjured limb revealed negative correlations between ERD1 and LAXA (r=-0.534) as well as between ERD2 and LAX2 (r=-0.565). ACLR patients demonstrate greater brain activation during joint loading in the injured knees when compared to healthy controls' matched knees as well as contralateral healthy knees, while the CONT group shows similar brain activation patterns during joint loading between limbs. These different neural activation strategies may indicate neuromechanical decoupling following an ACL reconstruction and evidence of altered sensorimotor perception and control of the knee (neuroplasticity), which may be critical to address after surgery for optimal neuromuscular control and patients' outcomes.

Gait Biomechanics in Anterior Cruciate Ligament-reconstructed Knees at Different Time Frames Postsurgery.

To examine knee and hip biomechanics during walking and jogging in groups of ACLR patients at early, mid, and late time frames postsurgery and healthy controls. Participants included individuals with a history of primary, unilateral ACLR, stratified into early (1.4 ± 0.4 yr post, n = 18), mid (3.3 ± 0.6 yr post, n = 20), and late (8.5 ± 2.8 yr post, n = 20) ACLR groups based on time postsurgery, and a healthy control group (n = 20). Walking and jogging motion capture analysis of knee and hip kinetics and kinematics were measured in the sagittal and frontal planes. Interlimb (within groups) and between-group comparisons were performed for all gait variables. Statistical comparisons were made across the gait cycle by plotting graphs of means and 90% confidence intervals and identifying regions of the gait cycle in which the 90% confidence intervals did not overlap. Early ACLR group demonstrated reduced knee flexion, knee extension, knee adduction, and hip adduction moments on the ACLR limb. Mid ACLR group demonstrated no gait differences between limbs or other groups. Late ACLR group demonstrated reduced knee flexion moments, and greater knee and hip adduction moments in their ACLR limb. Control group demonstrated no interlimb differences. Walking and jogging gait biomechanics presented differently in patients at different stages in time after ACLR surgery. The early ACLR group demonstrated lower sagittal and frontal plane joint loading on the ACLR limb compared with contralateral and control limbs. The mid ACLR group did not demonstrate any gait differences compared with the contralateral or control limb. The late ACLR group demonstrated lower sagittal plane joint loading compared with control limbs and greater frontal plane joint loading compared to contralateral and control limbs.

Landing biomechanics in anterior cruciate ligament reconstructed females who pass or fail a functional test battery

BackgroundA functional test battery (FTB) has been proposed to determine return to full activity following anterior cruciate ligament reconstruction (ACLR). However, there is little biomechanical evidence of FTB usefulness. The purpose of this study was to compare knee joint landing and cutting biomechanics between ACLR patients who passed (ACLR-Pass), failed (ACLR-Fail), and healthy females (Healthy) before and after exercise. MethodsThirty females were included: 10 ACLR-Pass, eight ACLR-Fail and 12 Healthy. Participants performed a FTB consisting of The 2000 International Knee Documentation Committee Subjective Knee Evaluation Form, the Knee Outcome Survey Activities of Daily Living Scale, and quadricep strength and single-leg hop tests. Double-leg jump landing (DLJL) and single-leg jump cutting (SLJC) biomechanics were assessed before and after exercise. ResultsSignificant main effects of exercise were found during DLJL: lesser knee flexion angle at initial contact after exercise (before exercise: 15.8 ± 5.0, after exercise: 14.2 ± 5.4, P = 0.01, ηp 2 = 0.25); and during SLJC: smaller peak knee extension moment (before exercise: −0.33 ± 0.1, after exercise: −0.31 ± 0.1, P = 0.02, ηp 2 = 0.18). While there was a significant group by time interaction effect with lesser peak knee flexion angle after exercise, this interaction effect was likely driven by a reduction in peak knee flexion in only the Healthy group. ConclusionsHealthy females exhibited a reduction in peak knee flexion during SLJC after exercise. However, there were no differences in ACLR knee biomechanics during DLJL and SLJC performed before and after exercise.

Analysis of Motor Coordination Alteration after Anterior Cruciate Ligament Reconstruction

Research background and hypothesis. The Anterior cruciate ligament (ACL) is the most commonly injured ligament of the knee and its injuries result in significant functional impairment. Injury to the ACL is associated with altered knee joint loading and impaired neuromuscular control, which defined as the ability to produce well controlled movements and dynamic balance.Research aim. The aim of this study was to evaluate motor coordination and functional capacity of patients who received rehabilitation program following ACL reconstruction.Research methods. The study included 15 males aged 33.7 ± 2.49 years who had undergone unilateral ACL reconstruction with a semitendinosus/gracilis (STG) graft in Kaunas Clinical hospital. For objective functional testing, we used figure-of-eight movement coordination test. The Lysholm questionnaire was included as a disability outcome measure following ACL injury and reconstruction. The patients were assessed preoperatively and after 5 and 21weeks postoperatively.Research results. The results of this study indicated that motor coordination timescale showed significant differences (p &lt; 0.05) between the injured and the healthy legs before surgery and after 5 and 21 weeks. The movement coordination test data showed that there the timescale significantly longer on the injured knee compared with the noninjured knee. After 21 weeks of rehabilitation we found significantly lower (p &lt; 0.05) values in injured knees compared with the preoperative data. In injured knee the timescale after 21 weeks of rehabilitation was significantly (p &lt; 0.05) longer compared with noninjured knee.The Lysholm questionnaire scale indicated that there was a significant difference in the results for values (p &lt; 0.05) before surgery and after 21 weeks of rehabilitation. The questionnaire scale data showed that after 21 weeks of rehabilitation results for values was significantly (p &lt; 0.05) highest compared with before surgery and after 5 weeks.Discussion and conclusions. There was improvement in the injured leg in mean motor coordination timescale 21 weeks after ACL reconstruction, but the timescale was higher than in the uninjured leg. After 21 weeks of ACL reconstruction knee functional status in most patients was good or excellent.Keywords: knee joint, the Lysholm questionnaire, movement coordination test.

Tibiofemoral joint contact area and stress after single-bundle anterior cruciate ligament reconstruction with transtibial versus anteromedial portal drilling techniques

BackgroundDuring single-bundle ACLR, femoral tunnel location plays an important role in restoring the intact knee mechanisms, whereas malplacement of the tunnel was cited as the most common cause of knee instability. The objective of this study is to evaluate, objectively, the tibiofemoral contact area and stress after single-bundle (SB) anterior cruciate ligament reconstruction (ACLR) with femoral tunnel positions drilled by transtibial (TT) or anteromedial (AM) portal techniques.MethodsSeven fresh human cadaveric knees underwent ACLR by the use of TT or AM portal techniques in a randomized order. These specimens were reused for ACL-R (TT and AM). The tibiofemoral contact area and stresses were gauged by an electronic stress-sensitive film inserted into the joint space. The knee was under the femoral axial compressive load of 1000 N using a biomechanics testing machine at 0°, 10°, 20°, and 30° of flexion. Three conditions were compared: (1) intact ACL, (2) ACLR by the use of the TT method, and (3) ACLR by the use of the AM portal method.ResultsCompared with AM portal ACL-reconstructed knees, a significantly decreased tibiofemoral contact area on the medial compartment was detected in the TT ACL-reconstructed knees at 20°of knee flexion (P = .047). Compared with the intact group, the TT ACLR group showed a higher mean stress at 20° and 30° of flexion on the medial compartments (P = .001, P = .003, respectively), while the AM portal ACLR group showed no significant differences at 30° of flexion (P = .073). The TT ACLR group also showed a higher mean maximum stress at 20° of flexion on the medial compartments (P = .047), while the AM portal ACLR group showed no significant differences at this angle(P = .319).DiscussionThe alternation of the tibiofemoral joint contact area and stress in reconstructed knees may be caused by the mismatch of the tibiofemoral joint during knee movement procedures compared with intact knees.ConclusionsSB ACLR by the use of the AM portal method and TT method both alter the tibiofemoral contact area and stress when compared with the intact knee. When compared with the TT technique, ACLR by the AM portal technique more closely restores the intact tibiofemoral contact area and stress at low flexion angles.

The hamstring/quadriceps ratio is an indicator of function in ACL-deficient, but not in ACL-reconstructed knees.

The purpose of this study was to investigate the isokinetic, eccentric and isometric hamstring/quadriceps (HQ) ratios in patients before and after ACL reconstruction (ACLR) using bone-patellar tendon grafts and to establish the relationships between HQ ratio and knee function. Forty-four patients (mean age of 26.6years) underwent isokinetic testing of quadriceps and hamstring muscles before and after ACLR and HQ ratios were calculated. Lysholm, IKDC and Cincinnati Scores were used to assess function. Isokinetic concentric and eccentric peak torque (Nm/kg) was measured at three different speeds: 60, 120, and 180°/s. Isometric strength was tested at 30° and 60° of knee flexion. For the isometric tests, the HQ ratio between the involved and non-involved limb was not different for the ACLD knee (p = 0.28) at 30° knee flexion, but significant at the 60° flexion angle (p = 0.02) and for the ACLR knees at 30° and 60° (p = 0.02). For the isokinetic tests, the ratio between involved and non-involved limb was significant for ACL-deficient knees at both 60 (p = 0.039) and 120°/s (p = 0.05). There were significant differences between limbs for all speeds in ACLR knees (p = 0.0003-0.01). For the eccentric tests, the HQ ratio between the involved and non-involved limbs was not significant for both the ACLD (p = 0.19) and ACLR knees (p = 0.29) at the speed of 60°/s. At 120 and 180°/s, there were significant differences between limbs for both the ACLD (p = 0.02) and ACLR knees (p = 0.003). Linear regression did not reveal significant relationships between Cincinnati, Lysholm, and IKDC scores and HQ ratios in the ACLD (R2 = 0.35, p = 0.58; R2 = 0.34, p = 0.63; R2 = 0.38, p = 0.49). In contrast, there were significant correlations between the Lysholm and IKDC scores and HQ ratios in the ACLR knees (R2 = 0.84, p = 0.002; R2 = 0.86, p = 0.001). The findings of this study suggest that the HQ ratio in ACLD patients was not a predictor, but an indicator of patient-perceived knee function following ACLR. Level IV, case series.