Anterior Knee Laxity Research Articles

Impact of Surgical Timing on Clinical Outcomes in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Using Hamstring Tendon Autografts.

Background:To date, no studies have analyzed the influence on clinical outcomes of the interval between an anterior cruciate ligament (ACL) injury and double-bundle (DB) reconstruction with hamstring tendon autografts.Hypotheses:(1) Performing ACL reconstruction sooner after an injury will reduce postoperative anterior and rotatory knee instability, (2) postoperative range of knee motion or functional results will not be affected by different intervals between injury and surgery, and (3) preoperative isokinetic peak torque of the quadriceps and hamstring muscles will be lower in patients undergoing surgery earlier, while postoperative muscle strength will not be affected by surgery timing.Study Design:Cohort study; Level of evidence, 3.Methods:This study was conducted on a total of 171 patients who had undergone anatomic DB ACL reconstruction with hamstring tendon autografts. The patients were divided into 3 groups based on the time to surgery: (1) ≤1 month after the injury (group E; n = 25), (2) between 1 and 3 months after the injury (group M; n = 72), and (3) >3 months after the injury (group D; n = 74). Patients were assessed for a minimum of 2 years after surgery.Results:Concerning postoperative anterior laxity, 1-way analysis of variance demonstrated a significant difference (P = .0274) among the 3 groups. Anterior laxity was significantly less in group E than in group D (P = .0206). Spearman rank correlation analysis showed a significant correlation (ρ = 0.200; P = .0327) between anterior knee laxity and time to surgery. Also, a significant correlation (P = .0461) was found between the degree of the pivot-shift phenomenon and time to surgery. There were no significant differences in loss of knee extension or flexion among the 3 groups, nor were there any differences in the Lysholm knee score or International Knee Documentation Committee grade. Postoperatively, there were no significant differences in peak torque of the quadriceps or hamstring muscles among the 3 groups.Conclusion:Early DB reconstruction led to significantly less anterior laxity compared with delayed reconstruction. There were no significant differences in postoperative range of knee motion or functional results among the 3 time intervals between injury and surgery in this study.

Higher frequency of osteoarthritis in patients with ACL graft rupture than in those with intact ACL grafts 30\xa0years after reconstruction

PurposeThe aim was to assess the results of anterior cruciate ligament (ACL) reconstruction regarding graft failure, knee laxity, and osteoarthritis (OA) from a longterm perspective. It was hypothesized that intact ACL graft reduces the risk for increased OA development.MethodsThe cohort comprised 60 patients with a median follow-up 31 (range 28–33) years after ACL reconstruction. They were evaluated with magnetic resonance imaging, radiography, KT-1000 arthrometer and the pivot shift test.ResultsOut of the 60 patients, 30 (50%) showed an intact ACL graft and 30 (50%) a ruptured or absent ACL graft. Patients with ruptured ACL grafts had more medial tibiofemoral compartment OA than those with an intact ACL graft (p = 0.0003). OA was asymmetric in patients with ruptured ACL grafts with more OA in the medial than in the lateral tibiofemoral compartment (p = 0.013) and the patellofemoral compartment (p = 0.002). The distribution of OA between compartments was similar in patients with an intact ACL graft. KT-1000 values of anterior knee laxity were higher in patients with ruptured compared to those with intact ACL grafts (p = 0.012). Side-to-side comparisons of anterior knee laxity showed higher KT-1000 values in patients with ruptured ACL graft (p = 0.0003) and similar results in those with intact graft (p = 0.09). The pivot shift grade was higher in the group with a ruptured ACL graft (p < 0.0001).ConclusionsMedian 31 (range 28–33) years after ACL reconstruction, 50% of the patients showed an intact ACL graft and no side-to-side difference regarding anterior knee laxity. Patients with ruptured ACL grafts had more OA of the medial tibiofemoral compartment than those with intact ACL grafts.Level of evidenceRetrospective cohort study, Level III.

No long-term tunnel enlargement following anterior cruciate ligament reconstruction using autograft hamstring tendon with dual suspensory fixation.

Bone tunnel widening following anterior cruciate ligament reconstruction (ACLR) is well documented, although the aetiology and clinical significance of this phenomenon remain unclear. At mid-term follow-up, a greater prevalence of tunnel enlargement has been reported with the use of hamstring (HS) grafts. However, there are paucity of data on what happens in the longer term. The aim of this study was to assess the change in femoral and tibial tunnel dimensions 15years after four-strand HS ACLR. This is a retrospective review of 15 patients who underwent arthroscopic ACLR using HS autograft tendon and were followed up radiographically at 4months, 2years and 15years. Suspensory fixation was used for both ends of the graft. The diameters of the bone tunnels on posteroanterior (PA) and lateral radiographs were measured using digital callipers. Repeated measures analysis of variance (ANOVA) was used to examine change in tunnel width over time. Radiographic tunnel width did not significantly change between 4months and 2years. However, a significant decrease in width was found for both the femoral and tibial tunnels between the 2- and 15-year follow-up (P < 0.01): the femoral tunnel decreased by 50% and 51% in the PA and lateral views, respectively; the tibial tunnel decreased by 77% and 91% in the PA and lateral views respectively. There was no significant correlation between femoral or tibial tunnel width and flexion and extension deficits or with side to side differences in anterior tibial laxity at 15years. This radiographic follow-up study of bone tunnel widening following HS ACLR with suspensory fixation demonstrated that tunnel width did not increase beyond 4months and in fact had decreased significantly at long-term (15years) follow-up. There was no correlation between tunnel width changes and clinical assessment of flexion and extension deficits or with side-to-side anterior knee laxity at 15-years. IV.

Over-the-top ACL reconstruction restores anterior and rotatory knee laxity in skeletally immature individuals and revision settings.

To investigate the objective outcomes following anterior cruciate ligament reconstruction (ACLR) with the over-the-top (OTT) technique. Thirty-five ACL-deficient patients with mean follow-up of 2.2years were retrospectively reviewed. This included 14 skeletally immature individuals (age: 14 ± 1years) who underwent primary OTT ACLR (adolescent group) and 21 skeletally mature individuals (age: 25 ± 8years) who underwent OTT revision ACLR (revision group). The tibial tunnel was created at the anatomic position for all cases. No lateral extra-articular tenodesis was performed. Before and after surgery, the side-to-side difference (SSD) in anterior laxity was measured using KT-1000 arthrometer. Lachman and pivot-shift tests were assessed according to IKDC grade. The graft failure rate was assessed. The post-operative SSD in anterior laxity was significantly reduced in the adolescent (pre-op, 3.9 ± 1.8mm; post-op, 1.2 ± 0.8mm; p = 0.040) and revision groups (pre-op, 4.2 ± 1.7mm; post-op, 1.2 ± 1.4mm; p < 0.001). Postoperative knee laxity measured by Lachman and pivot-shift tests were also significantly improved in both groups. Graft rupture occurred in two patients in the adolescent group (14.3%), and one patient in the revision group (4.8%). ACLR with the OTT technique restored anterior and rotatory knee laxity in skeletally immature individuals and in revision settings. This one-step procedure may be a good option for skeletally immature individuals and revision settings. IV.

Quadriceps tendon autograft ACL reconstruction has less pivot shift laxity and lower failure rates than hamstring tendon autografts.

Quadriceps tendon (QT) autograft ACL reconstruction was hypothesized to possess less anterior knee laxity, pivot shift laxity, and lower failure rates than hamstring tendon (HT) autografts. Terms "hamstring tendon autograft" and "ACL reconstruction" or "quadriceps tendon autograft" and "ACL reconstruction" were searched in Embase and PubMed. Inclusion criteria required that studies included patients treated for primary ACL injury with reconstruction using either a QT autograft (Group 1) or a HT autograft (Group 2) and instrumented anterior knee laxity assessment. Extracted information included surgical fixation method, graft type, graft thickness or diameter, single vs. double bundle surgical method, publication year, time between the index knee injury and surgery, % women, initial and final subject number, subject age, follow-up length, side-to-side anterior knee laxity difference, Lysholm Score, Subjective IKDC score, anterior knee laxity side-to-side difference grade, ipsilateral pivot shift laxity grade, and failure rate. The Methodological Index for Nonrandomized Studies was used to evaluate study methodological quality. The QT group (Group 1) had 17 studies and the HT group (Group 2) had 61 studies. Overall, Group 2 had greater pivot shift laxity (OR 1.29, 95% CI 1.05-1.59, p = 0.005). Group 2 suspensory femoral fixation had greater pivot shift laxity (OR 1.26, 95% CI 1.01-1.58, p = 0.02) than Group 1 compression femoral fixation. Group 2 compression femoral fixation also had more anterior knee laxity (OR 1.25, 95% CI 1.03-1.52, p = 0.01) than Group 1 compression femoral fixation and higher failure rates based on initial (OR 1.69, 95% CI 1.18-2.4, p = 0.002) and final (OR 1.89, 95% CI 1.32-2.71, p = 0.0003) subject number. Failure rate for HT compression femoral fixation was greater than suspensory femoral fixation based on initial (OR 2.08, 95% CI 1.52-2.84, p < 0.0001) and final (OR 2.26, 95% CI 1.63-3.16, p < 0.0001) subject number. Overall, QT autografts had less pivot shift laxity and lower failure rates based on final subject number than HT autografts. Compression QT autograft femoral fixation had lower pivot shift laxity than suspensory HT autograft femoral fixation. Compression QT autograft femoral fixation had less anterior knee laxity and lower failure rates than compression HT autograft femoral fixation. Suspensory HT autograft femoral fixation had lower failure rates than compression HT autograft femoral fixation. Greater knee laxity and failure rates may be related to a combination of HT autograft diameter and configuration (tissue quality and dimensions, strands, bundles, and suturing method) variability and fixation mode. Level IV.

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 Menstrual Cycle May Affect Anterior Knee Laxity and the Rate of Anterior Cruciate Ligament Rupture: A Systematic Review and Meta-Analysis.

Women have a higher risk of anterior cruciate ligament (ACL) tears than men, the causes of which are multifactorial. The menstrual cycle and its hormonal effect on the knee may contribute to knee laxity and ACL injury. This work reviewed published studies examining the effects of the phases of the menstrual cycle on anterior knee laxity and the rate of ACL tears. A systematic review with meta-analysis and meta-regression was performed. Studies with data comparing the menstrual cycle phase with ACL injury or anterior knee laxity were included for analysis. Data with regard to patient demographic characteristics, anterior knee laxity, ACL injury, and menstrual cycle phases were extracted from the included studies. In this study, 1,308 search results yielded 396 articles for review, of which 28 met inclusion criteria. Nineteen studies of knee laxity with 573 combined subjects demonstrated a mean increase in laxity (and standard deviation) of 0.40 ± 0.29 mm in the ovulatory phase compared with the follicular phase and a mean increase in laxity of 0.21 ± 0.21 mm in the luteal phase compared with the follicular phase. Nine studies examining ACL tears with 2,519 combined subjects demonstrated a decreased relative risk (RR) of an ACL tear in the luteal phase compared with the follicular and ovulatory phases combined (RR, 0.72 [95% confidence interval, 0.56 to 0.89]). There were no differences in ACL tear risk between any of the other phases. An increased risk of an ACL tear does not appear to be associated with periods of increased laxity in this meta-analysis. Although this suggests that hormonal effects on an ACL tear may not be directly related to increases in knee laxity, the methodologic heterogeneity between published studies limits the conclusions that can be drawn and warrants further investigation. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Residual remnant preserving anatomic double-bundle anterior cruciate ligament reconstruction using hamstring tendon autografts

Residual remnant tissue preservation of the anterior cruciate ligament (ACL) has attracted notice in ACL reconstruction. There is a possibility that residual remnant tissue preserving technique has several potential advantages to accelerate the graft remodeling, such as improved anterior knee laxity, accelerated cell infiltration and revascularization, increased mechanoreceptors, and reduction of bone tunnel enlargement. Recently, the authors reported a new remnant tissue preserved procedure for anatomic double-bundle (DB) ACL reconstruction using the transtibial tunnel technique. The anterior and rotational knee laxities were significantly less in the remnant-preserved group than in the remnant-resected group. The 2 nd look observation showed that the remnant-preserved group was significantly better than the remnant-resected group. In this article, the authors described the surgical technique and clinical outcomes of the residual remnant preserving DB ACL reconstruction.

Optimal cutoff score for patient-reported outcome measures after anterior cruciate ligament reconstruction using load-displacement curve analysis.

To assess psychological components after anterior cruciate ligament (ACL) injury, we developed a new patient-reported outcome measure, the Japanese anterior cruciate ligament injury questionnaire 25 (JACL-25), and demonstrated that the JACL-25 is valid, reliable, and sufficiently responsive to evaluate psychological factors that are associated with outcomes in individuals with ACL injuries. The purpose of this study was to identify the optimum cutoff score for the JACL-25 that indicates successful clinical outcomes, combining with the graphical data obtained using the KT-2000. We studied 30 patients who underwent primary ACL reconstruction with a patella tendon or hamstring tendon autograft. On the same day of the JACL-25 evaluation, anterior knee laxity tests were performed using the KT-2000 arthrometer. ACL stiffness was calculated on the graphs of the hysteresis, which can be used to measure side-to-side differences in anterior translation. Akaike's information criterion (AIC) was used to determine the most appropriate cutoff level for the JACL-25 score for the stiffness reduction ratio and anterior-posterior (AP) translation. The average JACL-25 score was 23.8 (standard deviation (SD) 18.4). The average side-to-side displacement difference in AP translation was 2.4 (SD 4.2) mm. The average stiffness reduction ratio was 24.4% (SD 31.8). The smallest AIC values for the cutoff level for the JACL-25 score, the stiffness reduction ratio, and side-to-side differences of the anterior translation were 9, 27%, and 1.1 mm, respectively. We determined the optimal cutoff score for the JACL-25 that identifies successful clinical outcomes.

Clinical Tests Can Be Used to Screen for Second Anterior Cruciate Ligament Injury in Younger Patients Who Return to Sport.

Background:Younger athletes have high rates of second anterior cruciate ligament (ACL) injury. Return-to-sport criteria have been proposed to enable athletes to make a safe return, but they frequently lack validation. It is unclear whether commonly recorded clinical measures can help to identify high-risk athletes.Purpose:To explore the association between commonly recorded clinical outcome measures and second ACL injury in a young, active patient group.Study Design:Cohort study; Level of evidence, 2.Methods:Included in this study were 329 athletes (200 males, 129 females) younger than 20 years at the time of first primary ACL reconstruction surgery who had subsequently returned to sport participation. Clinical examination included range of knee motion (passive flexion and extension deficits), instrumented anterior knee laxity, and single- and triple-crossover hop for distance. Patients also completed the subjective International Knee Documentation Committee form. All measures were collected prospectively at a 12-month postoperative clinical review. Patients were evaluated for a minimum 3 years to determine the incidence of subsequent ACL injury.Results:A total of 95 patients (29%) sustained a second ACL injury following clinical assessment and return to sport. There were 50 graft ruptures and 45 contralateral ACL injuries. Patients with a flexion deficit of 5° had over 2 times the odds of sustaining a graft rupture (odds ratio, 2.3; P < .05), and patients with a side-to-side difference in anterior knee laxity of 3 mm or greater had over 2 times the odds of sustaining a contralateral ACL injury (odds ratio, 2.4; P < .05). Overall, 29% (94 of 329) of patients met the threshold for satisfactory function on all 6 clinical measures; these patients had a 33% reduction in the risk of sustaining a second ACL injury (P = .05) as compared with those who did not meet all clinical thresholds.Conclusion:Clinical measures of knee flexion and stability may have utility to screen for and identify patients who are at greater risk for a second ACL injury in an already high-risk group (ie, age and activity level).

Minimal tibial tunnel enlargement after anatomic rectangular tunnel anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft

BackgroundThe purpose of this study was to evaluate the tibial tunnel enlargement after the anatomical rectangular tunnel (ART) anterior cruciate ligament reconstruction (ACLR) with a bone-patellar tendon-bone (BTB) graft and to elucidate the correlation between the enlargement and length of the tendinous portion inside the tibial tunnel. In addition, we aimed to analyze the correlation between patient characteristics and tibial tunnel enlargement. MethodsThis study included 50 patients who underwent ART ACLR. Lateral radiographs at the time of surgery and at 2 years were compared to evaluate the tibial tunnel enlargement. Subsequently, correlations between the tunnel enlargement and (1) length of tendinous portion inside the tibial tunnel or (2) characteristics of the patients, including anterior knee laxity measured by KT-1000 arthrometer, age, sex, height, body weight, and Tegner activity level scale, were analyzed. ResultsThe tibial tunnel was enlarged by 2.6 ± 4.2% 2 years postoperatively. The length of the tendinous portion inside the tibial tunnel was 7.8 ± 4.9 mm. There was no significant correlation between tunnel enlargement and length of tendinous portion inside the tunnel. None of the patient characteristics were detected as a risk factor for tibial tunnel enlargement. Conclusions(1) The postoperative tibial tunnel enlargement was minimum after ART ACLR with a BTB graft. (2) There was no correlation between tibial tunnel enlargement and length of tendinous portion of BTB graft inside the tunnel. (3) None of the patient characteristics were detected as a risk factor of the tibial tunnel enlargement.

Anterior and Rotational Knee Laxity Does Not Affect Patient-Reported Knee Function 2 Years After Anterior Cruciate Ligament Reconstruction

Background: While a primary goal of anterior cruciate ligament (ACL) reconstruction is to reduce pathologically increased anterior and rotational knee laxity, the relationship between knee laxity after ACL reconstruction and patient-reported knee function remains unclear. Hypothesis: There would be no significant correlation between the degree of residual anterior and rotational knee laxity and patient-reported outcomes (PROs) 2 years after primary ACL reconstruction. Study Design: Cross-sectional study; Level of evidence, 3. Methods: From a prospective multicenter nested cohort of patients, 433 patients younger than 36 years of age injured in sports with no history of concomitant ligament surgery, revision ACL surgery, or surgery of the contralateral knee were identified and evaluated at a minimum 2 years after primary ACL reconstruction. Each patient underwent Lachman and pivot-shift evaluation as well as a KT-1000 arthrometer assessment along with Knee injury and Osteoarthritis Outcome Score and subjective International Knee Documentation Committee (IKDC) scores. A proportional odds logistic regression model was used to predict each 2-year PRO score, controlling for preoperative score, age, sex, body mass index, smoking, Marx activity score, education, subsequent surgery, meniscal and cartilage status, graft type, and range of motion asymmetry. Measures of knee laxity were independently added to each model to determine correlation with PROs. Results: Side-to-side manual Lachman differences were IKDC A in 246 (57%) patients, IKDC B in 183 (42%) patients, and IKDC C in 4 (<1%) patients. Pivot-shift was classified as IKDC A in 209 (48%) patients, IKDC B in 183 (42%) patients, and IKDC C in 11 (2.5%) patients. The mean side-to-side KT-1000 difference was 2.0 ± 2.6 mm. No significant correlations were noted between pivot-shift or anterior tibial translation as assessed by Lachman or KT-1000 and any PRO. All predicted differences in PROs based on IKDC A versus B pivot-shift and anterior tibial translation were less than 4 points. Conclusion: Neither the presence of IKDC A versus B pivot-shift nor increased anterior tibial translation of up to 6 mm is associated with clinically relevant decreases in PROs 2 years after ACL reconstruction.

Tibiofemoral Kinematics During Compressive Loading of the ACL-Intact and ACL-Sectioned Knee: Roles of Tibial Slope, Medial Eminence Volume, and Anterior Laxity.

Tibial geometry and knee laxity have been identified as risk factors for both noncontact anterior cruciate ligament (ACL) rupture and instability in the setting of ACL insufficiency via clinical studies; yet, their biomechanical relationships with tibiofemoral kinematics during compressive loading are less well understood. The purpose of this study was to identify the relative contributions of sagittal tibial slope, medial tibial eminence volume, and anterior knee laxity to tibiofemoral kinematics with axial compression in both ACL-intact and ACL-sectioned cadaveric knees. Computed tomography (CT) data were collected from 13 human cadaveric knees (mean donor age, 45 ± 11 years; 8 male). Validated algorithms were used to calculate the sagittal slope of the medial and of the lateral tibial plateau as well as volume of the medial tibial eminence. Specimens were then mounted to a robotic manipulator. For both intact and ACL-sectioned conditions, the robot compressed the knee from 10 to 300 N at 15° of flexion; the net anterior tibial translation of the medial and lateral compartments and internal tibial rotation were recorded. Simple and multiple linear regressions were performed to identify correlations between kinematic outcomes and (1) osseous geometric parameters and (2) anterior laxity during a simulated Lachman test. In ACL-intact knees, anterior tibial translation of each compartment was positively correlated with the corresponding sagittal slope, and internal tibial rotation was positively correlated with the lateral sagittal slope and the sagittal slope differential (p ≤ 0.044). In ACL-sectioned knees, anterior tibial translation of the medial compartment was positively associated with medial sagittal slope as well as a combination of medial tibial eminence volume and anterior laxity; internal tibial rotation was inversely correlated with anterior knee laxity (p < 0.05). Under compressive loading, sagittal slope of the medial and of the lateral tibial plateau was predictive of kinematics with the ACL intact, while medial tibial eminence volume and anterior laxity were predictive of kinematics with the ACL sectioned. The relationships between tibial osseous morphology, anterior laxity, and knee kinematics under compression may help explain heightened risk of ACL injury and might predict knee instability after ACL rupture.

Tibial tunnel enlargement after anatomic anterior cruciate ligament reconstruction with a bone–patellar tendon–bone graft. Part 2: Factors related to the tibial tunnel enlargement

BackgroundFactors related to tunnel enlargement after anterior cruciate ligament (ACL) reconstruction should be evaluated by multivariate analysis, because the phenomenon has multifactorial characteristics. The purpose of this study was to elucidate the factors related to the tibial tunnel enlargement rate after anatomic ACL reconstruction with a bone–patellar tendon–bone (BTB) graft using multivariate analysis. MethodsEighteen patients with unilateral ACL rupture were included. The anatomic rectangular-tunnel (ART) ACL reconstruction with a BTB autograft was performed. 3D CT models of the tibia, the tibial tunnel, and the bone plug at 3 weeks and 1 year after surgery were reconstructed and superimposed using a surface registration technique. The cross-sectional area (CSA) of the tibial tunnel perpendicular to the tunnel axis was evaluated at the aperture. The CSA was measured at 3 weeks and 1 year after surgery, and the tunnel enlargement rate at the aperture was calculated. Multiple linear regression analysis was performed to detect the significantly related factors to the tibial tunnel enlargement rate at the aperture among potential factors consisting of preoperative demographic factors and predisposing factors with the tibial tunnel. ResultsThe tibial tunnel enlargement rate at the aperture was 21.9 ± 14.1% (mean ± standard deviation). Multiple linear regression analysis detected the tendon length inside the tunnel as a significantly independent factor related to the tibial tunnel enlargement rate at the aperture (standardized β = 0.726, P = 0.008). There was no significant relationship between the tibial tunnel enlargement rate at the aperture and postoperative side-to-side difference (SSD) of the anterior knee laxity or Tegner activity level scale under single linear regression analysis. ConclusionThe greater tendon length inside the tunnel was independently related to the higher tibial tunnel enlargement rate at the aperture 1-year after anatomic ACL reconstruction with a BTB graft under multiple linear regression analysis.

Prevalence, development, and factors associated with cyst formation after meniscal repair with the all-inside suture device.

To investigate the prevalence of cyst formation after using all-inside meniscal repair device and analysed the risk factors associated with it. Between August 2008 and September 2013, 51 menisci of 46 patients were included in the study, 46 menisci of which had concomitant anterior cruciate ligament (ACL) ruptures and had an ACL reconstruction. Magnetic resonance imaging (MRI) of the knee was performed at 3, 6, 12 and 24 months after meniscal surgery. The MRIs were assessed to detect the development of cysts encasing the suture anchors and to evaluate meniscal healing. Statistical analysis was performed using multiple regression analysis. Out of the 51 menisci examined, MRI revealed cysts in 15 menisci. Cysts were detected in 3 menisci at 6 months, in 9 menisci at 12 months, and in 3 menisci at 24 months after surgery. Only 3 patients (6.5%) were symptomatic, and cystectomy was performed in 2 of these patients and arthroscopic debridement in the other. Compared with using both the suture device and an inside-out suture repair, using the suture device alone was more likely to be associated with cyst development [odds ratio (OR), 12.04]. The medial meniscus was also significantly more likely to develop a cyst compared with the lateral meniscus (OR, 12.48). There was an increased outcome for the number of device use (P = 0.033). Though it was not statistically significant, the patients with anterior knee laxity (side-to-side difference > 3mm using a knee arthrometer) were more likely to develop cysts than those without anterior knee laxity (P = 0.06). There were no significant differences between the remaining variables. The prevalence of cyst formation around the suture implant was 29%, but most cases were not symptomatic. Significant risk factors for cyst formation included the use of a suture device alone, and a location in the medial meniscus. III.

Primary ACL reconstruction using the LARS device is associated with a high failure rate at minimum of 6-year follow-up.

The Ligament Augmentation and Reconstruction System (LARS®) is a synthetic ligament consisting of fibres made of polyethylene terephthalate. Despite the LARS being used as an anterior cruciate ligament (ACL) device for nearly 30years and the well-documented complications from earlier synthetic ligament designs, there is a paucity of published medium- to long-term results. The aim of this study is to report the clinical and functional outcomes after ACL reconstruction using the LARS at a minimum follow-up of 6years. Results of a single surgeon's entire cohort of 55 patients who underwent primary LARS ACL surgery were reviewed at a median of 7.8years (6.0-9.4). Patient-reported outcome measures including the International Knee Documentation Committee (IKDC) score and 36-Item Short Form Health Survey (SF-36) were collected and clinical assessment consisted of range of motion (ROM) and the KT-1000 arthrometer to assess the side-side difference in the operative and non-operative knee. Mechanical failures of the graft were confirmed at revision surgery and a survivorship analysis was performed using the Kaplan-Meier method. The overall mechanical failure rate was 17/51 (33.3%) with ruptures occurring at a median 3.9years (0.6-8.8years) following primary LARS ACL surgery. Secondary operative procedures were performed in 39.2% of patients. For intact grafts, there was no statistically significant difference is side-to-side ROM or anterior knee laxity and subjective scores revealed a median IKDC subjective score of 85.1 (26.4-100) and SF-36 physical component score of 94.1. The rates of LARS ACL construct failure (33.3%) in this cohort are high and based on these results the LARS should not be considered as a graft option for primary ACL reconstruction. III, cohort study.

Minimal Ablation of the Tibial Stump Using Bony Landmarks Improved Stability and Synovial Coverage Following Double-Bundle Anterior Cruciate Ligament Reconstruction.

PurposeTo evaluate the clinical effects of using anatomical bony landmarks (Parsons’ knob and the medial intercondylar ridge) and minimal ablation of the tibial footprint to improve knee anterior instability and synovial graft coverage after double-bundle anterior cruciate ligament reconstruction.Materials and MethodsWe performed a retrospective comparison of outcomes between patients who underwent reconstruction with minimal ablation of the tibial footprint, using an anatomical tibial bony landmark technique, and those who underwent reconstruction with wide ablation of the tibial footprint. Differences between the two groups were evaluated using second-look arthroscopy, radiological assessment of the tunnel position, postoperative anterior knee joint laxity, and clinical outcomes.ResultsUse of the anatomical reference and minimal ablation of the tibial footprint resulted in a more anterior positioning of the tibial tunnel, with greater synovial coverage of the graft postoperatively (p=0.01), and improved anterior stability of the knee on second-look arthroscopy. Both groups had comparable clinical outcomes.ConclusionsUse of anatomical tibial bony landmarks that resulted in a more anteromedial tibial tunnel position improved anterior knee laxity, and minimal ablation improved synovial coverage of the graft; however, it did not significantly improve subjective and functional short-term outcomes.

In-vivo elongation of anterior and posterior cruciate ligament in bi-cruciate retaining total knee arthroplasty.

Anterior and posterior cruciate ligament (ACL and PCL) sacrifice in contemporary total knee arthroplasty (TKA) has been considered a potential factor leading to abnormal knee kinematics. Bi-cruciate retaining (BCR) TKA design allows retention of both ACL and PCL. However, there is a limited data on the ACL/PCL in-vivo elongation characteristics of BCR TKA. The study aimed to evaluate and compare the in-vivo elongation patterns of ACL/PCL between BCR TKA and contralateral non-implanted knee and to explore potential factors leading to the changed elongation patterns between limbs. ACL/PCL elongations of both knees during sit-to-stand were measured in 29 unilateral BCR TKA patients using a validated dual fluoroscopic tracking technique. Joint gap changes of the BCR TKA knees relative to the contralateral knee were quantified. BCR TKA and the contralateral non-implanted knee exhibited similar ACL elongation at extension and clinical anterior knee laxity. However, BCR TKA showed significantly greater PCL elongation during flexion than the non-implanted knee. Variation of changed elongation was observed for both ACL and PCL, suggesting a heterogeneous restoration of normal ACL/PCL functions. A significant correlation was found between extension joint gap change and the change of ACL elongation, highlighting the importance of precise joint line restoration and soft tissue balancing during BCR TKA surgery. Our findings suggest that BCR TKA did not fully restore "near-normal" cruciate ligament elongation patterns and anteroposterior stability. Considerable heterogeneity remains in the retained ligament elongation patterns and warrants further investigations of multifactorial factors to optimize ACL/PCL functions in BCR TKA. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3239-3246, 2018.

Influence of the Anterolateral Ligament on Knee Laxity: A Biomechanical Cadaveric Study Measuring Knee Kinematics in 6 Degrees of Freedom Using Dynamic Radiostereometric Analysis.

Background:An anterior cruciate ligament (ACL) rupture often occurs during rotational trauma to the knee and may be associated with damage to extracapsular knee rotation–stabilizing structures such as the anterolateral ligament (ALL).Purpose:To investigate ex vivo knee laxity in 6 degrees of freedom with and without ALL reconstruction as a supplement to ACL reconstruction.Study Design:Controlled laboratory study.Methods:Cadaveric knees (N = 8) were analyzed using dynamic radiostereometry during a controlled pivotlike dynamic movement simulated by motorized knee flexion (0° to 60°) with 4-N·m internal rotation torque. We tested the cadaveric specimens in 5 successive ligament situations: intact, ACL lesion, ACL + ALL lesion, ACL reconstruction, and ACL + ALL reconstruction. Anatomic single-bundle reconstruction methods were used for both the ACL and the ALL, with a bone-tendon quadriceps autograft and gracilis tendon autograft, respectively. Three-dimensional kinematics and articular surface interactions were used to determine knee laxity.Results:For the entire knee flexion motion, an ACL + ALL lesion increased the mean knee laxity (P < .005) for internal rotation (2.54°), anterior translation (1.68 mm), and varus rotation (0.53°). Augmented ALL reconstruction reduced knee laxity for anterior translation (P = .003) and varus rotation (P = .047) compared with ACL + ALL–deficient knees. Knees with ACL + ALL lesions had more internal rotation (P < .001) and anterior translation (P < .045) at knee flexion angles below 40° and 30°, respectively, compared with healthy knees. Combined ACL + ALL reconstruction did not completely restore native kinematics/laxity at flexion angles below 10° for anterior translation and below 20° for internal rotation (P < .035). ACL + ALL reconstruction was not found to overconstrain the knee joint.Conclusion:Augmented ALL reconstruction with ACL reconstruction in a cadaveric setting reduces internal rotation, varus rotation, and anterior translation knee laxity similar to knee kinematics with intact ligaments, except at knee flexion angles between 0° and 20°.Clinical Relevance:Patients with ACL injuries can potentially achieve better results with augmented ALL reconstruction along with ACL reconstruction than with stand-alone ACL reconstruction. Furthermore, dynamic radiostereometry provides the opportunity to examine clinical patients and compare the recontructed knee with the contralateral knee in 6 degrees of freedom.

Return to Level I Sports After Anterior Cruciate Ligament Reconstruction: Evaluation of Age, Sex, and Readiness to Return Criteria.

Background:Return to sport (RTS) after anterior cruciate ligament (ACL) reconstruction is a topic of current interest. The high reinjury rates reported in younger athletes may be due in part to an early RTS.Purpose:To determine the proportion of athletes who return to level I (jumping, hard pivoting, and cutting) sport at less than 1 year after ACL reconstruction and compare return rates by age and sex. A secondary purpose was to examine whether RTS is associated with some commonly used outcome criteria.Methods:A cohort of 1440 athletes (992 males, 448 females) satisfied criteria for inclusion in this study (primary ACL reconstruction, normal contralateral knee, no additional surgery within the first year after the reconstruction, and participation in level I sport on a weekly basis prior to injury). The proportion of athletes in this sample who had resumed level I sport by 12 months after surgery was recorded, along with measurements of knee function (single-legged hop symmetry), laxity (KT-1000 arthrometer), and self-reported outcomes (International Knee Documentation Committee [IKDC] subjective score). Limb symmetry index scores of 90 or higher, side-to-side difference in anterior knee laxity of 2 mm or less, and IKDC scores of 95 or higher were considered indicators of satisfactory recovery from surgery.Results:Rates of return to level I sport were significantly higher for athletes aged 25 years and younger (48% return rate) compared with older athletes (26-35 years, 32% return rate [P < .0001]; ≥36 years, 19% return rate [P < .001]). Male athletes who were in the ≤25-year and 26- to 35-year age brackets had significantly higher return rates than female athletes (52% vs 39% and 37% vs 18%, respectively), whereas no sex-based differences in RTS were seen after 36 years of age. A significantly higher proportion of younger patients met the selected indicators of a satisfactory recovery. Regardless of age, athletes had twice the odds of RTS if they had limb symmetry index scores of 90 or higher (P ≤ .0001) and 3 times the odds of RTS if they had IKDC scores of 95 or higher (P < .0001).Conclusion:Almost half of younger athletes (aged ≤25 years) in the current cohort returned to level I sports within 12 months after ACL reconstruction. Younger athletes were also more likely to meet criteria that indicate a satisfactory functional recovery and that have been used to indicate readiness to RTS. There may be a role for adjusting thresholds for these criteria based on age.