KT-1000 Arthrometer Research Articles

Comparison of Rotatory and Sagittal Laxity After Single-Bundle Versus Double-Bundle ACL Reconstruction: Outcomes at 7-Year Follow-up.

Background:Biomechanical studies have shown excellent anteroposterior and rotatory laxity control after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction, but no clinical studies have compared midterm (>5-year) residual laxity between the DB and single-bundle (SB) techniques.Purpose:To clinically compare sagittal and rotatory laxities and residual sagittal laxity on the KT-1000 arthrometer between patients treated with an SB ACL reconstruction and those treated with a DB ACL reconstruction at the 7-year follow-up.Study Design:Cohort study; Level of evidence, 3.Methods:A total of 110 patients were included between January 2006 and December 2007. The patients were randomly assigned into 2 groups: those treated with SB ACL reconstruction (n = 63) and those treated with the DB technique (n = 47). All patients were then reviewed at a minimum of 7 years of follow-up; patients with ACL rerupture (n = 3 in the SB group and n = 2 in the DB group) were excluded from the postoperative comparative analysis. Residual anterior laxity (Lachman test), rotatory laxity (pivot-shift test), and sagittal laxity (KT-1000 arthrometer side-to-side difference) were measured and compared between the 2 groups.Results:The mean age at surgery was 23.0 ± 5.1 years for the DB group and 28.1 ± 7.0 years for the SB group, and the mean follow-up was 7.4 ± 0.8 years. No statistically significant differences were found between the 2 groups in terms of age, sex, preoperative laxity on KT-1000, preoperative Tegner score, or concomitant meniscal lesions. Residual postoperative laxity via Lachman testing (P < .01), pivot-shift testing (P = .042), and the KT-1000 arthrometer (P < .01) was statistically significantly in favor of DB reconstruction.Conclusion:DB ACL reconstruction allowed better control of anterior stability during the evaluation via the Lachman test and via objective measurement on the KT-1000, as well as rotatory stability at a minimum of 7 years of follow-up.

Anterior cruciate ligament rupture in a patient with Albers-Schonberg disease

BackgroundOsteopetrosis is an uncommon inherited disease marked with elevated bone density and frequent bone fractures owing to flawed osteoclast activity. Autosomal dominant osteopetrosis type 2 (ADO-2), a benign form of osteopetrosis, is also known as Albers-Schonberg disease.Case presentationWe report the first successful anterior cruciate ligament (ACL) reconstruction surgery for ACL rupture treatment in a 30-year-old female with ADO-2, who carried a heterozygous missense mutation c.2227C > T (p.Arg743Trp) in exon 23 of the chloride channel 7 (CLCN7) gene. Histopathological analysis of the ruptured ACL sample revealed massive calcium salt deposition in the ligament tissue. A ligament advanced reinforcement system (LARS) artificial ligament was employed in her ACL reconstruction surgery. At her final 16 month’s follow-up, she reported no knee instability symptoms and other complications. The range of motion of the affected knee was good. The side-to-side difference in knee laxity, as evidenced by a KT-1000 arthrometer was 0.9 mm. The Lysholm score improved from 45 before operation to 83 after operation. The Tegner activity score improved from 1 before operation to 4 after operation.ConclusionsOur findings further confirmed that the newly identified mutated locus (p.Arg743Trp) may lead to acid secretion disorders at different sites (including calcified ACL in our case). In terms of clinical treatment, ligament reconstruction surgery in patients with Albers-Schonberg disease presents a unique challenge to orthopedic surgeons and requires further preparation and time.

Diagnostic values of history taking, physical examination and KT-1000 arthrometer for suspect anterior cruciate ligament injuries in children and adolescents: a prospective diagnostic study

BackgroundDiagnosing anterior cruciate ligament (ACL) injuries in children and adolescents are more challenging compared to adults. Delayed diagnosis may result in meniscal or chondral injuries. The aim of this study was to determine the diagnostic values of history taking, physical examination and KT-1000 arthrometer for suspect ACL injuries in children and adolescents.MethodsIn this prospective diagnostic study, all children and adolescents (< 18 years) with post-traumatic knee complaints presenting at the out-patient department of the Máxima MC were eligible for inclusion. One experienced knee specialised orthopaedic surgeon was blinded and performed history taking, physical examination and KT-1000 arthrometer measurement. All patients had a magnetic resonance imaging (MRI) for the final diagnosis. Diagnostic values of interest were sensitivity, specificity, positive and negative predictive values (PPV and NPV). The outcomes of the KT-1000 arthrometer were drafted in a relative operating characteristics (ROC) curve to determine the optimal cut-off points.ResultsSixty-six patients were included, of which 50 had an ACL rupture and 16 had no ACL rupture on MRI. Report of a popping sensation during trauma had a specificity and PPV of 100% for diagnosing ACL injuries. The PPV and NPV of the Lachman test (in case of describing end-feel) were 95 and 82%, of the anterior drawer test 87 and 90% and of the pivot shift test 95 and 81% respectively. The optimal cut-off point of the KT-1000 arthrometer at 133 N force was an absolute translation of ≥7 mm with a PPV and NPV of 97 and 88% respectively.ConclusionsReport of a popping sensation during trauma has a specificity and PPV of 100% for diagnosing ACL injuries in children and adolescents. Although potentially difficult in children, the Lachman test, anterior drawer test and pivot shift test have a high PPV and NPV when performed by an experienced orthopaedic surgeon. An absolute anterior translation of ≥7 mm of the injured knee in the KT-1000 arthrometer at 133 N has the highest diagnostic values of all tests for diagnosing ACL injuries.Level of evidence3

Rates of Anterior Cruciate Ligament Rerupture in Adolescent Patients with and without Patella Alta.

The objective of this study was to compare rates of anterior cruciate ligament (ACL) failure among adolescent patients to evaluate patella alta as a high-risk variable. Demographic and surgical data were retrospectively queried for patients ≤18 years of age with primary ACL reconstruction performed at a single academic center between 2011 and 2016 and minimum of 2-year clinical surveillance. Patellar height indices, including Caton-Deschamps index (CDI) and Insall-Salvati index (ISI), were retrospectively calculated from preoperative imaging to assess the presence of patella alta. Failure was defined as (1) ACL graft rerupture, (2) Lachman's grade 2 + , (3) presence of pivot shift, and (4) side-to-side difference of 3 mm on KT-1000 arthrometer. A total of 184 patients (84 females and 100 males) and 192 knees were identified, with an average age of 16.2 ± 1.8 years. Of these, 30 (15.63%) experienced ACL failure. Male sex was the only significant risk factor for rerupture (p = 0.026). The mean CDI was 1.06 ± 0.17 and mean ISI was 1.04 ± 0.15. Of the 49 knees that met criteria for patella alta on radiographic evaluation, rerupture occurred in seven (14.29%). Patella alta was not a significant risk factor for ACL failure among adolescent patients (p = 0.359 and 0.277). Only male sex was associated with increased rates of ACL failure. Age, graft selection technique, fixation construct, and presence of patella alta were not risk factors for reinjury. This study is a therapeutic case series and reflects level of evidence IV.

Factors Influencing the Progression of Patellofemoral Articular Cartilage Damage After Anterior Cruciate Ligament Reconstruction.

Background:Although anterior cruciate ligament reconstruction (ACLR) can restore the stability and function of the knee joint, patellofemoral joint cartilage damage still progresses. Currently, the clinically important factors that lead to the progression of patellofemoral articular cartilage damage are not fully understood.Purpose:To investigate the factors that affect the progression of patellofemoral articular cartilage damage after ACLR.Study Design:Cohort study; Level of evidence, 2.Methods:Among 160 patients who underwent ACLR between January 2015 and December 2019, the authors evaluated 129 patients for at least 1 year after surgery. Within 1 week before ACLR and at the last follow-up, patients underwent subjective functional assessment and magnetic resonance imaging evaluations of articular cartilage damage (modified Outerbridge assessment). At the last follow-up, the side-to-side difference on KT-2000 arthrometer and bilateral quadriceps muscle strength were measured. Univariate and multivariate logistic regression analyses were performed.Results:The mean follow-up was 24.69 ± 10.74 months. Progression of patellar cartilage damage from preoperatively to final follow-up was seen in 45 patients (P < .001). Logistic regression analysis revealed that the follow-up period (P = .047; odds radio (OR) = 0.953) (improvement of patellar cartilage damage with longer follow-up), partial lateral meniscal resection (P = .004; OR = 6.929), partial medial meniscal resection (P = .004; OR = 6.032), and quadriceps muscle strength <80% of the contralateral side (P = .001; OR = 4.745) were risk factors for the progression of patellar cartilage damage.Conclusion:Cartilage damage at the patellofemoral joint, especially the patellar cartilage, still progresses after ACLR. At a mean follow-up of 24.69 months after ACLR, partial meniscal resection and quadriceps femoris muscle strength were found to be the main risk factors for the progression of patellofemoral articular cartilage damage after ACLR.

Association Between Early Postoperative Graft Signal Intensity and Residual Knee Laxity After Anterior Cruciate Ligament Reconstruction.

Background:Magnetic resonance imaging (MRI) graft signal intensity is associated with graft damage after anterior cruciate ligament reconstruction (ACLR). However, little is known about the relationship between graft signal intensity and residual laxity of the reconstructed knee based on patient age.Purpose/Hypothesis:To evaluate the relationship between graft signal intensity and residual laxity in younger and older patients who underwent ACLR. We hypothesized that higher graft signal intensity would be associated with reduced postoperative knee stability.Study Design:Cohort study; Level of evidence, 3.Methods:A total of 192 patients who underwent double-bundle ACLR were recruited. Proton density–weighted and T2-weighted MRI was performed at 3, 6, and 12 months after surgery, and the signal intensity ratio (SIR) of the anteromedial and posterolateral bundles was measured as the graft signal intensity reference values. At 12 months after surgery, if the KT-1000 arthrometer measurement exhibited a side-to-side difference of ≥2 mm, the patient was determined as having anterior knee laxity. Rotatory knee laxity was defined as a positive pivot shift with International Knee Documentation Committee grade ≥1. The Mann-Whitney U test was used to compare the SIR in patients with and without residual laxity. The Spearman correlation coefficient was used to evaluate the relationship between demographic parameters and the SIR. Based on receiver operating characteristic curves, the optimal SIR cutoff values to predict residual laxity were calculated, and logistic regression analysis was conducted.Results:Of 192 patients, 26 (13.5%) had anterior knee laxity, and 20 (10.4%) had rotatory knee laxity. The SIR was negatively correlated with age. In younger patients (<30 years; n = 135), those with residual laxity had a significantly higher SIR than those without laxity; this relationship was not significant in older patients (≥30 years; n = 57). Based on receiver operating characteristic curves and logistic regression analysis, the cutoff values that were determined for the SIR were significantly associated with a higher odds ratio of residual laxity.Conclusion:Graft signal intensity decreased with patient age. Patients with higher graft signal intensity in the early postoperative phase after ACLR exhibited a higher prevalence of residual laxity, particularly in younger patients.

Posterior cruciate ligament reconstruction with independent internal brace reinforcement: surgical technique and clinical outcomes with a minimum two year follow-up

PurposeWe developed an augmentation technique for PCL reconstruction with independent internal brace reinforcement and evaluated the functional outcome after PCL reconstruction employing autologous hamstrings augmented with an internal brace system for patients with isolated or combined grade 3 posterior instability who were treated with this technique.MethodsFrom January 2016 to January 2018, patients with isolated or combined grade 3 PCL tears who underwent single-bundle PCL reconstruction using autologous hamstrings augmented with independent internal braces were studied. The function of the operated knee was evaluated according to the International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity score. The patients were asked the level of returned to their previous sport. Posterior knee laxity was examined with a KT-1000 arthrometer, and data on range of motion (ROM), re-operation, and other complications were collected.ResultsA total of 33 consecutive patients who received single-bundle PCL reconstruction using autologous hamstrings augmented with independent internal braces with a minimum two years follow-up were included in this study. Two patients had undergone this procedure during the study period and were not included in this study (one had combined bone fractures, and one patient had previous meniscus surgery). Thirty-one patients were available for final analysis. The mean follow-up was 45.35 ± 10.88 months (range 29–66 months). The average IKDC subjective knee evaluation scores from 51.65 ± 12.35 to 84.52 ± 6.42, the Lysholm score from 53.90 ± 11.86 to 85.68 ± 4.99, and the Tegner score from 2.81 ± 0.79 to 6.71 ± 1.83 (P < 0.05 for all). The mean total posterior side-to-side difference in knee laxity, assessed using a KT-1000 arthrometer, decreased from 12.13 ± 2.66 mm pre-operatively to 1.87 ± 0.56 mm post-operatively at 70° (P < 0.05). Most patients (29/31) had normal or near normal knee ROM post-operatively; two patients revealed a 6–15° loss of knee flexion compared with the contralateral knee. Twenty-nine patients (93.55%) returned to a normal daily exercise level. Twenty-three patients (74.19%) returned to competitive sports with high-level sports (Tegner score of 6 or above; eleven patients (35.48%) reported to be on the same level as well as the Tegner level); six patients (19.35%) returned to recreational sports (Tegner score of 4 or 5). Two patients had Tegner scores of 2 and 3, indicating poor function level. No patient needed PCL revision surgery during the follow-up period.ConclusionSingle-bundle PCL reconstruction with internal brace augmentation for PCL injury exhibited satisfactory posterior stability and clinical outcomes in patients with isolated or combined grade 3 PCL injuries at a minimum two year follow-up.

Unilateral Versus Bilateral Resistance Exercise in Postoperative Rehabilitation After ACL Reconstruction With Bone-Patellar Tendon-Bone Graft: A Randomized Controlled Trial.

Background:Lower limb muscle strength symmetry has been suggested as an essential criterion for the safe return to sports after anterior cruciate ligament (ACL) reconstruction. Limited evidence is available regarding the most effective intervention to achieve symmetry after reconstruction with contralateral bone–patellar tendon–bone (BPTB) graft.Purpose:To verify whether unilateral isotonic resistance exercise is more effective than bilateral exercise for obtaining postoperative functional and muscular strength symmetry between the donor limb and reconstructed limb for patients who received BPTB graft.Study Design:Randomized controlled trial; Level of evidence, 1.Methods:A total of 88 patients were randomly divided into a control group (n = 44) and an intervention group (n = 44). All participants performed an 8-week exercise program starting at the beginning of the fourth postoperative month and were evaluated before and after the program. The control group performed bilateral exercises, and the intervention group performed unilateral exercises for the donor limb only (the limb with the greatest disability). The primary outcome was muscle strength (peak torque and hamstrings to quadriceps [H:Q] ratio), and the secondary outcomes were range of motion (ROM; goniometry), KT-1000 arthrometer side-to-side difference in anteroposterior knee laxity, and objective (single-leg hop test) and subjective (Lysholm score) functionality.Results:Both groups improved significantly from before to after the exercise program. The improvements were significantly greater in the intervention group regarding peak torque, H:Q ratio, flexion ROM, single-leg hop test, and Lysholm score in the donor limb (P < .001 for all), and the improvements were significantly greater in the control group regarding peak torque and single-leg hop test in the reconstructed limb (P < .001 for both). Comparison between the groups showed significantly increased symmetry regarding peak torque, H:Q ratio, and single-leg hop test in the intervention group compared with the control group (P < .001), with large effect sizes (>0.80) except for the H:Q ratio.Conclusion:Although postoperative, bilateral, isotonic resistance exercise provided better strength gains to the reconstructed limb, unilateral exercise was more effective in obtaining functional and muscle strength between-limb symmetry in patients who underwent ACL reconstruction with contralateral BPTB graft.Registration:Brazilian Registry of Clinical Trials (number RBR-22rnjh).

Risk factors of residual pivot-shift after anatomic double-bundle anterior cruciate ligament reconstruction.

Although anterior cruciate ligament reconstruction (ACLR) is considered a successful procedure, residual pivot-shift after surgery remains to be solved. The purpose of this study was to comprehensively evaluate the risk factors of residual pivot-shift after anatomic double-bundle (DB) ACLR. A total of 164 patients who underwent primary anatomic DB-ACLR between January 2014 and December 2019 and screw removal after the index ACLR in our hospital were included in this retrospective case-control study. The manual pivot-shift test was performed under general anesthesia during screw removal surgery, and patients with grade 1 or higher pivot-shift were classified as the positive pivot-shift group, and those with grade 0 were defined as the negative pivot-shift group. Univariate and logistic regression analyses were performed to identify the factors associated with postoperative residual pivot-shift. Assessment included sex, age, time to surgery, preoperative Tegner activity scale, preoperative pivot-shift grade, preoperative anterior tibial translation by the KT-2000 arthrometer measurement, meniscus injury and its surgical procedure, knee hyperextension, cartilage damage, Segond fracture, medial and lateral posterior tibial slope, lateral-medial slope asymmetry, participation in pivoting sport/activity at the time of injury, and return to sports at postoperative one year line. Postoperative positive pivot-shift was observed in 14 (8.5%) of 164 patients. The KT-2000 measurement at 1-year postoperatively was significantly higher in the residual pivot-shift-positive group than in the negative group (P < 0.05). Logistic regression analysis revealed that age of patients < 20years [P < 0.05, odds ratio (OR): 6.1)], preoperative pivot-shift grade (P < 0.05, OR: 4.4), and hyperextended knee (P < 0.05, OR: 11.8) were risk factors of postoperative pivot-shift. There were no statistically significant differences between other variables. Patients < 20years of age, with high-grade preoperative pivot-shift, or hyperextended knees had a higher risk of residual postoperative pivot-shift.

Large lateral tibial slope and lateral-to-medial slope difference are risk factors for poorer clinical outcomes after posterolateral meniscus root tear repair in anterior cruciate ligament reconstruction

BackgroundMeniscus root tear is an uncommon but detrimental injury of the knee. Hoop stress is lost during meniscus root tear, which can lead to excessive tibiofemoral contact pressure and early development of osteoarthritis. Posterolateral meniscus root tears (PLRT) are more commonly associated with anterior cruciate ligament (ACL) tears. As the lateral compartment is less congruent than the medial compartment, it is more susceptible to a shearing force, which is increased in the ACL-deficient knee. In accordance with the compressive axial load, the increase in the tibial slope would generate a greater shearing force. The additional lateral compartment mobility caused by ACL tear should be reduced after ACL reconstruction (ACLR). However, there is a lack of evidence to conclude that ACLR can sufficiently limit the effect of large tibial slope (LTS) on the healing after PLRT repair. This study aimed to evaluate whether a steep LTS would be a risk factor for poorer clinical outcomes after PLRT repair concomitant with ACLR.MethodsIn this retrospective study, a chart review was conducted to identify patients with concomitant unilateral primary ACLR and PLRT repair. Patients with a partial tear or healed tear were excluded. Postoperative MRI and clinical assessments were performed at a mean follow up of 35 months. MRI data was used to measure the LTS, medial tibial slope (MTS), coronal tibial slope (CTS), the lateral-to-medial slope difference (LTS-MTS) and meniscus healing and extrusion. Functional outcomes were evaluated by patient-reported outcomes (International Knee Documentation Committee [IKDC], Lysholm and Tegner scores) and KT-1000 arthrometer assessment. Interobserver reproducibility was assessed by two reviewers.ResultsTwenty-five patients were identified for the analysis. Patients with larger LTS and larger LTS-MTS differences were shown to be correlated with poorer IKDC scores after surgery (R = -0.472, p = 0.017 and R = -0.429, p = 0.032, respectively). Herein, patients with LTS ≥ 6° or LTS-MTS ≥ 3° demonstrated poorer IKDC scores.ConclusionA large LTS (≥ 6°) and a large difference of LTS-MTS (≥ 3°) were shown to be risk factors for poorer functional and radiological outcomes for PLRT repair in patients after ACLR. Clinically, closer monitoring and a more stringent rehabilitation plan for patients with LTS ≥ 6° or LTS-MTS ≥ 3° would be recommended.

Double-Bundle Versus Single-Bundle Anterior Cruciate Ligament Reconstruction in Patients With Significant Passive Anterior Tibial Subluxation

Background: Passive anterior tibial subluxation (PATS) is often observed in patients with anterior cruciate ligament tears. Postoperative outcomes of double-bundle (DB) and single-bundle (SB) anterior cruciate ligament reconstruction (ACLR) with significant PATS (>6 mm) are unclear. Hypothesis: DB-ACLR could achieve better stability and clinical outcomes than SB-ACLR in patients with PATS >6 mm. Study Design: Cohort study; Level of evidence, 3. Methods: Retrospective analysis was peformed on 626 consecutive patients who underwent primary anatomic ACLR between October 2016 and November 2017. Anterior subluxation of the lateral and medial compartments in extension relative to the femoral condyles was measured on preoperative magnetic resonance imaging scans. Among patients who demonstrated significant PATS (>6 mm) in the lateral compartment, 54 who underwent DB-ACLR (study group) were matched to 54 who underwent SB-ACLR (control group). PATS, stability (pivot-shift test and KT-2000 arthrometer), the Lysholm score, and the International Knee Documentation Committee (IKDC) grade were investigated preoperatively and at 3- to 4-year follow-up. Results: The preoperative mean PATS values in the lateral and medial compartments were not significantly different between groups (control vs study: lateral compartment, 8.1 ± 1.8 vs 8.5 ± 2.1 mm; medial compartment, 5.2 ± 1.9 vs 5.4 ± 1.9 mm; P > .05). Postoperatively, mean PATS values in the lateral and medial compartments of the study group were significantly improved as compared with the control group (control vs study: lateral compartment, 5.9 ± 2.8 vs 3.2 ± 4.1 mm; medial compartment, 3.7 ± 2.9 vs 1.4 ± 2.3 mm; P < .05). Significantly superior results were found for knee stability in the study group regarding the Lachman test (grade 0/1/2/3, study vs control: 29/22/3/0 vs 16/28/10/0; P = .031), pivot-shift test (grade 0/1/2/3, study vs control: 44/9/1/0 vs 30/19/5/0; P = .023), and KT-2000 arthrometer (study vs control: 2.5 ± 1.5 vs 3.9 ± 1.4 mm; P < .001). Clinical scores showed significantly better results in the study group in terms of IKDC score (study vs control: 87.9 ± 8.7 vs 81.2 ± 15.0; P = .01), Tegner activity score (study vs control: 6.0 ± 1.4 vs 4.9 ± 1.5; P < .001), and Lysholm score (study vs control: 91.7 ± 7.0 vs 86.3 ± 11.4; P = .004). Conclusion: DB-ACLR achieved better knee stability and clinical outcomes when compared with SB-ACLR in patients with PATS >6 mm at 3- to 4-year follow-up.

Correlation Between Y-Balance Test and Balance, Functional Performance, and Outcome Measures in Patients Following ACL Reconstruction.

BackgroundThe Y-Balance test (YBT) is commonly used to evaluate balance after anterior cruciate ligament reconstruction (ACLR). However, several studies have also used it as a functional performance test (FPT).PurposeThis study aimed to examine the relationship between YBT scores and measures of knee joint laxity, static balance, knee flexor and extensor torque and strength ratio, and FPTs.Study DesignRetrospective cohort study.MethodsFifty-nine patients who underwent ACLR using hamstring autografts were retrospectively analyzed. The Pearson correlation coefficient was used to determine the strength of the association between scores on the YBT and selected outcomes including laxity measured via the KT-2000 arthrometer, static balance measured via the Biodex Balance System, isokinetic muscle torque and hamstring-to-quadriceps (HQ) ratio, and performance on the single leg hop test and the single leg vertical jump test.ResultsForty-six men and 13 women were included. The mean age and follow-up period were 29.6 ± 9.6 years and 12.4 ± 2.1 months, respectively. The KT-2000 arthrometer measures, Biodex Balance System scores, and HQ ratio measurements were not significantly correlated with the YBT scores. All YBT scores, except the YBT-anterior score, correlated with the isokinetic extensor and flexor torques (r-values: 0.271–0.520). All the YBT scores had significant weak to moderate correlations with the single leg hop test and single leg vertical jump test scores: YBT-anterior (r = 0.303, r = 0.258), YBT-posteromedial (r = 0.475, r = 0.412), YBT-posterolateral (r = 0.525, r = 0.377), and YBT-composite (r = 0.520, r = 0.412).ConclusionPost-ACLR YBT scores correlated with functional performance and muscle strength, but not with static balance, joint laxity, and HQ ratios. The YBT scores as a measure of balance are related to improved functional performance and isokinetic torque measures.Level of evidence3

Reliability of a Novel Automatic Knee Arthrometer for Measuring Knee Laxity After Anterior Cruciate Ligament Ruptures.

Background:The accuracy of existing devices for measuring knee laxity is adversely affected by examiner reliability.Purpose:To compare the accuracy of a novel automatic knee arthrometer (AKA) to that of the KT-2000 arthrometer for measuring knee laxity after anterior cruciate ligament (ACL) ruptures.Study Design:Cohort study; Level of evidence, 2.Methods:We measured anterior displacement and the anterior displacement difference (ADD) at 134 N of anterior force in 221 healthy volunteers and 200 patients with ACL ruptures. All trials were performed by the same 2 examiners. We first analyzed the effects of examiner, side assessed, and device type using the intraclass correlation coefficient (ICC), t test, and F test. We then used the receiver operating characteristic curve to compare the diagnostic value of the measurements between devices.Results:In repeated measurements for a single healthy volunteer, there were no differences in the variance of the measurements between sides according to the AKA (standard deviation of right vs left knee for examiner A: 0.43 vs 0.58 mm, respectively [P = .39]; for examiner B: 0.49 vs 0.77 mm, respectively [P = .81]), while the KT-2000 measurements showed differences (standard deviation of right vs left knee for examiner A: 1.47 vs 0.80 mm, respectively [P = .02]; for examiner B: 1.78 vs 0.91 mm, respectively [P = .01]). The ADD assessed by the AKA was not significantly different between examiners A and B (0.50 vs 0.75 mm, respectively; P = .27; ICC = 0.83), but the KT-2000 showed a difference (1.07 vs 2.01 mm, respectively; P = .01; ICC = 0.55). The ADD of 20 healthy volunteers assessed by the AKA was less than that by the KT-2000 (0.98 vs 1.41 mm, respectively; P = .04). When comparing the diagnostic value of the 2 devices in the sample of 200 patients with ACL ruptures and 200 healthy controls, the area under the receiver operating characteristic curve for the AKA was larger than that for the KT-2000 (0.93 vs 0.87, respectively; P ≤ .01), and the threshold values were 1.75 and 2.73 mm, respectively.Conclusion:The AKA can be used to determine the degree of knee laxity in ACL injuries and to provide indications for treatment.

Lateral extraarticular tenodesis improves stability in non-anatomic ACL reconstructed knees: in vivo kinematic analysis.

To carry out an in vivo kinematic analysis to determine whether adding a lateral extraarticular tenodesis (LET) for those patients with subjective instability and objective residual laxity after a transtibial (TT) anterior cruciate ligament reconstruction (ACLR) reduces anteroposterior and rotational laxity and to evaluate the 2-year follow-up clinical outcomes to analyze whether biomechanical changes determine clinical improvement or not. A total of 19 patients with residual knee instability after TT ACLR who underwent a modified Lemaire LET were prospectively evaluated for at least 2-year follow-up. Preoperative, intraoperative, and 6 and 24-month postoperative kinematic analyses were carried out using the KiRA accelerometer and KT1000 arthrometer to look for residual anterolateral rotational instability and residual anteroposterior instability. Functional outcomes were measured with the single-leg vertical jump test and the single-leg hop test. Clinical outcomes were evaluated using the IKDC 2000, Lysholm, and Tegner scores. A significant reduction in anterolateral rotational instability was detected with the patient under anesthesia (from 3 ± 1.2 to 1.1 ± 1.1m/s2; p < 0.05) as well as with the patient awake (from 2.1 ± 0.8 to 0.7 ± 1.4m/s2; p < 0.05). A significant reduction in anteroposterior instability was only present under anesthesia (from 3.4 ± 1.9 to 2.1 ± 1.1mm; p < 0.05), while no difference was present without anesthesia (from 2.3 ± 1.1 to 1.6 ± 1mm; n.s.). Postoperative analysis of knee laxity did not show any significant variation from the first to the last follow-up. Both the single-leg vertical jump test and single-leg hop test improved significantly at the last follow-up (both p < 0.05). The mean values of both the IKDC and Tegner scores showed an improvement (p < 0.05 and p < 0.05, respectively), whereas that was not the case with the Lysholm score (n.s.). The modified Lemaire LET can improve the kinematics of a non-anatomic ACL reconstructed knee with residual subjective and objective instability. These kinematic changes were able to lead to an improvement in subjective stability as well as the function of the knee in a small cohort of recreationally active patients. At 2-year follow-up, the kinematic changes as well as the level of activity of the patients and the IKDC score show their improvement sustained. Level IV.

Does anterolateral ligament internal bracing improve the outcomes of anterior cruciate ligament reconstruction in patients with generalized joint hypermobility?

Generalized joint hypermobility (GJH) is a risk factor for anterior cruciate ligament (ACL) injury and ACL graft failure and is considered an indication for anterolateral ligament (ALL) reconstruction. The aim of this retrospective study was to compare functional outcomes, rupture rates, and residual instability in patients with GJH undergoing isolated ACL reconstruction or combined ACL reconstruction and ALL augmentation with internal bracing (ALL-IB). Sixty-eight patients with GJH and unilateral ACL injury were randomly assigned to undergo either isolated ACL reconstruction (Group 1) or combined ACL reconstruction and ALL-IB (Group 2). The patients were evaluated pre- and postoperatively; their medical histories; physical examination results; anterior knee translation, as measured using the KT-1000 arthrometer; and scores of validated knee assessments were recorded. Groups 1 and 2 consisted of 37 and 31 patients, respectively. The mean follow-up was 30.1±4.1 and 28.1±2.9 months, respectively. In the final evaluation, the patients in Group 2 showed better rotational stability, as evaluated by the pivot-shift test (p=0.013); better anteroposterior stability, as evaluated by KT-1000 arthrometry (p=0.001); similar function (p=0.14 for the Lysholm, p=0.11 for the Cincinnati, and p=0.19 for the International Knee Documentation Committee subjective score); and failure rate (p=0.41). The functional outcomes were similar between the groups. The stability outcomes after combined ACL and ALL-IB were better than those after isolated ACL reconstruction in patients with GJH. However, the technique and its results need to be validated in larger patient series and prospective randomized controlled trials.

Does a Lower Limb Balance Test after Anterior Cruciate Ligament Reconstruction Have a Significant Correlation with Postoperative Clinical Score, Stability, and Functional Performance Test?

Lower limb balance ability is reduced after anterior cruciate ligament reconstruction (ACLR). However, the recovery of balance based on functional test scores after ACLR is not known because the correlation between balance and clinical scores remains unclear. We aimed to analyze the correlation between lower limb balance assessed by functional test and clinical knee test scores after ACLR. We evaluated lower limb balance using the anterior-posterior stability index (APSI) of the Biodex Balance System (BBS). Patients underwent clinical tests to evaluate the knee, including the Tegner activity score, International Knee Documentation Committee (IKDC) subjective score, Lysholm score, and KT-2000 arthrometer measurement, hamstring per quadriceps muscle strength ratio at 60°/sec (HQ ratio), and functional performance tests (single-leg hop and single-leg vertical jump tests) 1 year after ACLR. We used a paired t-test to compare continuous preoperative and postoperative variables and Pearson's correlation coefficient to determine the relationship between BBS-APSI and clinical scores. Forty-eight patients (35 men and 13 women; mean age, 28.9 ± 8.3 years) were included. The follow-up period and BBS-APSI were 12.4 ± 2.0 months and 0.9 ± 0.4, respectively. Tegner activity score, IKDC subjective score, Lysholm score, and KT-2000 arthrometer measurement improved significantly postoperatively (p < 0.001). BBS-APSI was correlated with the Tegner activity score (r = -0.335, p = 0.020), IKDC subjective score (r = -0.301, p = 0.037), Lysholm score (r = -0.323, p = 0.025), single-leg hop test results (r = -0.300, p = 0.038), and single-leg vertical jump test results (r = -0.336, p = 0.019). There was no correlation between KT-2000 arthrometer measurement and HQ ratio. BBS-APSI was correlated with functional performance test scores after ACLR, rendering the BBS-APSI as a useful assessment tool to evaluate postoperative functional recovery. Continuously improving balance after ACLR could be useful for functional recovery after surgery.

Effects of Platelet-Rich Plasma on Clinical Outcomes After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis.

Background:Many studies have documented the use of platelet-rich plasma (PRP) alongside anterior cruciate ligament (ACL) reconstruction (ACLR) in the management of ACL injury, but evidence on the benefits of PRP in improving the clinical outcomes of ACLR is inconsistent.Purpose:To help in our understanding, we undertook a systematic review and meta-analysis of randomized controlled trials (RCTs) that evaluated the effects of PRP on patient-reported functional scores, the clinical assessments of knee function and structure, and complications.Study Design:Systematic review; Level of evidence, 1.Methods:We searched 9 online databases for RCTs published in English or Chinese that examined the effects of PRP on ACLR. The primary outcome measures were visual analog scale (VAS) for pain and International Knee Documentation Committee (IKDC) scores. The secondary outcomes included KT-1000 arthrometer, pivot-shift test, Lysholm and Tegner scores, tunnel widening, graft characterization, and complications. Subgroup analyses were performed according to time of assessments. Fixed- and random-effects models were selected for data analysis.Results:A total of 14 studies were included. When PRP was injected to graft tunnels, the pooled VAS scores of the 2 groups were similar (P = .31), and the subgroup analysis found that VAS and IKDC only improved at 3 months postoperatively (P = .0003 and P < .00001, respectively). When PRP was used at the bone–patellar tendon–bone harvest sites, VAS was decreased in the first 6 months postoperatively (P < .00001), whereas IKDC score was not remarkably different (P = .07). After PRP injection, Lysholm scores at 3 months postoperatively was different between the 2 groups (P < .00001), but the Tegner scores (P = .86), KT-1000 measurements (P = .12), the positive rate of pivot-shift test (P = .64), the enlargement of tunnels (femoral, P = .91; tibial, P = .80), and the characterization of grafts (P = .05) were not different. No difference in complications was found in either group.Conclusion:PRP applied alongside ACLR could reduce postoperative pain and improve knee function in the short and medium terms but is ineffective in the long term. PRP does not improve knee stability and the enlargement of tunnels and does not accelerate the healing of grafts. Further studies would be required.

The Addition of Suture Tape to the Hamstring Graft Construct Does Not Reduce Instrumented Knee Laxity Following ACL Reconstruction

PurposeTo establish the effect of the addition of suture tape to the hamstring graft construct through measurement of instrumented sagittal plane knee laxity at 6 months after anterior cruciate ligament reconstruction (ACLR).MethodsA retrospective analysis was undertaken of a consecutive series of primary ACLR performed between May 2017 and June 2019. Patients with concomitant or historic contralateral knee injury were excluded. Suture tape was included in the graft construct from the midpoint of the study period (May 2018). Sagittal plane knee laxity was quantified using the KT2000 arthrometer at 6 postoperative months. Mean side-to-side differences in sagittal plane laxity between the operated and contralateral, uninjured knees were compared for grafts with and without suture tape. Additional outcomes included comparison between suture tape application techniques (graft reinforcement versus augmentation), comparison between suture tape with and without iliotibial band (ITB) tenodesis and documentation of complications necessitating further surgery.ResultsA total of 169 patients were eligible for inclusion. Seventy-two grafts included suture tape and 84 patients underwent concomitant ITB tenodesis. There was no significant difference in mean laxity between grafts containing suture tape (mean difference: 1.2 mm, SD: 2.6 mm) and those without (mean difference: 1.3 mm, SD: 2.1 mm), P = .83 (CI −.92 to 1.13). Neither were there significant differences in laxity when using suture tape with concomitant ITB tenodesis (mean difference: 1.1 mm, SD: 2.1 mm), P = .75 (CI −.79 to 1.09), or when comparing techniques: graft reinforcement (mean difference .9 mm, SD 2.6 mm); graft augmentation (mean difference: 1.5 mm, SD: 2.5 mm) P = .52 (CI −2.29 to 1.16). There were no complications associated with suture tape.ConclusionsThe addition of suture tape to an autologous hamstring graft construct did not reduce instrumented sagittal knee laxity in the first 6 months after ACL reconstruction. As such, the clinical relevance of its use remains unknown.Level of EvidenceLevel III, retrospective cohort study.

ACL Reconstruction Combined With the Arnold-Coker Modification of the MacIntosh Lateral Extra-articular Tenodesis: Long-term Clinical and Radiological Outcomes

Background: Interest in the role of lateral extra-articular tenodesis (LET) in preventing rotatory instability and the pivot-shift phenomenon after anterior cruciate ligament reconstruction (ACLR) has been recently renewed. Nevertheless, there is still concern about overconstraint of the lateral compartment of the knee and the risk of subsequent osteoarthritis (OA). Purpose: The purpose of this retrospective study was to compare long-term subjective and objective outcomes and the rate of OA development between patients undergoing isolated ACLR (iACLR) with a hamstring tendon autograft and those with a combined Arnold-Coker modification of the McIntosh extra-articular procedure. Risk factors for long-term OA were evaluated. Study Design: Cohort study; Level of evidence, 3. Methods: The study included 165 consecutive patients treated at a single center by ACLR. A total of 86 patients underwent iACLR (iACLR group) and 79 received combined intra- and extra-articular reconstruction (ACLR+LET). The International Knee Documentation Committee (IKDC), Lysholm, and Tegner activity scores were administered. Knee stability was tested through the Lachman test, the pivot-shift test, and the KT-1000 knee arthrometer test. A positive pivot-shift test (++/+++), laxity on the KT-1000, and referred giving-way episodes or revision ACLR were considered failures. Radiographic results were assessed according to the Fairbank, IKDC, and Kellgren-Lawrence scales. Radiographic evaluation included both the overall tibiofemoral joint and the medial and lateral compartment separately. A univariate and a multivariate logistic regression with penalized maximum likelihood was used to identify risks factors associated with long-term OA. Results: The mean follow-up was 15.7 years. There were no statistically significant differences in subjective scores between the 2 groups. A side-to-side difference >5 mm on the KT-1000 arthrometer evaluation was found in 8 patients in the iACLR group and in 1 patient in the ACLR+LET group (P = .01). Nine cases of failure were found in the iACLR group and only 1 case was found in the ACLR+LET group (P = .0093). Patients in the iACLR group had a significantly higher OA grades than those in the ACLR+LET group for the overall tibiofemoral joint and the lateral compartment of the knee. No differences were found in the medial compartment. A higher level of lateral compartment OA was found in patients who received partial lateral meniscectomy in the iACLR group compared with those in the ACLR+LET group. Univariate and multivariate analysis results demonstrated that meniscectomy was the most significant factor for long-term OA development. Conclusion: A significantly higher risk of long-term OA was found with iACLR than with ACLR combined with the Arnold-Coker modification of the McIntosh extra-articular procedure. Knees with combined ACLR also had a significantly lower OA grade after partial lateral meniscectomy. Additionally, those undergoing combined ACLR had better knee stability and lower graft rupture rates at the long-term follow-up. Partial meniscectomy was the main risk factor negatively associated with OA changes.

Proprioceptive and Clinical Outcomes after Remnant Preserved Anterior Cruciate Ligament Reconstruction: Assessment with Minimal Confounding Factors.

ObjectiveTo evaluate the proprioceptive and clinical function of the knee joint after anterior cruciate ligament reconstruction (ACLR) with various amounts of remnant preserved with as few confounding factors as possible.MethodsThis retrospective study included 46 patients who underwent ACLR with remnant preservation between March 2013 and February 2019. These patients had less than 6 months injury‐to‐surgery interval and no concomitant injuries. The researchers divided these subjects into two groups based on the length of the remnant preserved after ACLR, with group A defined as having more than 1/3 of the original length preserved and group B defined as less than 1/3 of the original length preserved. Clinical scores were obtained using the Lysholm knee scoring scale and the Tegner activity scale. The Lysholm score was calculated preoperatively, at 3, 6, and 12 months postoperatively, and at the last follow up. The Tegner score was calculated preoperatively, at 12 months postoperatively and at the last follow up. Anterior laxity was measured using the KT2000 arthrometer preoperatively and at 12 months postoperatively. Proprioceptive function was evaluated through reproduction of passive positioning (RPP) and threshold to detection of passive motion (TDPM). Both RPP and TDPM were measured at the angle of 15° at 3, 6, and 12 months postoperatively. Unpaired t‐tests were performed to investigate the difference in each parameters between the two groups.ResultsIn the present study, 20 patients were classified into group A and 26 into group B. All patients were followed up for an average of 34.70 ± 12.79 months. All 46 patients were satisfied with the outcome of the surgery and no complications were reported at the end of the study. No significant differences were found between the two groups in terms of the Lysholm score and anterior laxity by KT2000 at all time points. The Tegner score was significantly higher in group A at 12 months postoperatively and at the final follow‐up. In addition, group A's RPP was significantly better than that of group B's when tested at the angles of 15° and 30° at 3 months postoperatively, and at the angle of 15° at 6 months postoperatively. Group A's TDPM was also significantly better than that of group B's at all three tested angles at 3 months postoperatively, and at the angle of 15° at 6 months postoperatively.ConclusionPatients with ACLR with more than 1/3 of the original length preserved demonstrated a higher activity level 12 months postoperatively and better proprioceptive function at 15° of extension at 3 and 6 months postoperatively.