Contralateral Uninjured Knee Research Articles

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

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

Neuromuscular Training Improves Self-Reported Function and Single-Leg Landing Hip Biomechanics in Athletes After Anterior Cruciate Ligament Reconstruction.

Background:Neuromuscular training (NMT) has been shown to attenuate high-risk biomechanics in uninjured athletes. At the time that athletes return to sport after anterior cruciate ligament (ACL) reconstruction (ACLR), they demonstrate hip biomechanical deficits associated with injury to the reconstructed knee versus the uninjured contralateral knee.Purpose:The primary purpose of the study was to examine whether an NMT program can improve single-leg drop (SLD) landing hip biomechanics for athletes after ACLR. Secondarily, we compared the posttraining SLD hip biomechanics of athletes after ACLR with a control group of athletes who also completed the NMT program.Study Design:Controlled laboratory study.Methods:A total of 18 ACLR and 10 uninjured athletes were recruited and completed a 12-session NMT program. A knee-specific questionnaire and biomechanics of an SLD task was evaluated for each athlete before and after NMT. Paired t tests were used to compare pre- and posttraining International Knee Documentation Committee (IKDC) scores. Repeated-measures analysis of variance (ANOVA) was performed to assess the main effects and interactions of testing session × limb for the ACLR athletes. A 2-way ANOVA was conducted to quantify the interactions and main effects of group × limb.Results:There was a significant increase (P = .03) in IKDC scores from pre- to posttraining. For the ACLR athletes, there was a significant session × limb interaction for hip external rotation moment (P = .02) and hip abduction angle (P = .013). Despite increases in hip external rotation moment, no significant changes from pre- to posttraining were observed for the involved limbs. No significant changes were observed for hip abduction angle of the involved limbs between training sessions. Significant main effects of session (P < .05) revealed that athletes landed with greater hip excursion, lower hip flexion moment, and lower ground-reaction force after training. The posttraining comparison between the ACLR and control groups found no significant group × limb interactions for any of the hip kinematic or kinetic variables. A significant main effect of group (P < .05) revealed that the ACLR athletes landed with greater hip flexion angle and hip external rotation moment.Conclusion:ACLR athletes demonstrated an improvement in SLD hip biomechanics and neuromuscular control after participating in an NMT program.Clinical Relevance:This evidence indicates a potential role for NMT to improve hip biomechanics during an SLD task so as to reduce ACL injury risk.

Single-Leg Squat After Anterior Cruciate Ligament Reconstruction: An Analysis of the Knee Valgus Angle at 6 and 12 Months.

Background:Deficits in neuromuscular control are common after anterior cruciate ligament (ACL) reconstruction and may be associated with further knee injury. The knee valgus angle during a single-leg squat (SLS) is one measure of neuromuscular performance.Purpose:To determine whether the knee valgus angle during SLS changes between 6 and 12 months after ACL reconstruction and to assess how the operative knee valgus angle compares with that of the contralateral side.Study Design:Case series; Level of evidence, 4.Methods:A cohort of 100 patients with uninjured contralateral knees were assessed at 6 and 12 months after primary hamstring autograft ACL reconstruction. Participants performed the SLS on each leg, and the knee valgus angle was measured via frame-by-frame video analysis at 30° of flexion and at each patient’s maximum knee flexion angle.Results:For the operative limb at 30° of flexion, a small but statistically significant reduction was noted in the valgus angle between 6 and 12 months (5.46° vs 4.44°; P = .002; effect size = 0.24). At 6 months, a slightly higher valgus angle was seen in the operative limb compared with the nonoperative limb (5.46° vs 4.29°; P = .008; effect size = 0.27). At maximum flexion, no difference was seen between limbs in the valgus angle at either 6 or 12 months, and no change was seen in the operative limb between 6 and 12 months. At 6 months and 30° of knee flexion, 13 patients had a valgus angle greater than 10°. This group also had a higher mean valgus angle in the contralateral limb compared with the contralateral limb in the other 87 patients (8.5° vs 3.65°; P < .001).Conclusion:During a controlled SLS, the knee valgus angle remained essentially constant, and minimal limb asymmetries were present over the 6- to 12-month postoperative period, a time when athletes typically increase their activity levels. Whether changes or asymmetries will be seen with more dynamically challenging tasks remains to be determined. When present, high valgus angles were commonly bilateral.

Do BTB ACLR Knees have more MRI signs of PTOA than their Contralateral Normal Knee at 2 Years?

Objectives:The prevalence of patellofemoral joint (PFJ) osteoarthritis (OA) ranges from 8-47% 7-10 years after anterior cruciate ligament reconstructions (ACLR) using bone-patellar tendon-bone (BTB) autograft. In performing BTB ACLR, some hypothesize that either trauma caused by harvest of the patellar bone autograft or altered biomechanics lead to PFJ post traumatic osteoarthritis (PTOA). Our objective was to evaluate by 3T MRI whether the ACLR knees had more signs of early PTOA compared to the contralateral knee within the MOON nested cohort. We hypothesize that a BTB autograft harvested using a minimally traumatic technique will not increase the risk of PFJ OA.Methods:MRIs of operative and contralateral uninjured knees were collected in 60 patients (28 males, mean age 21 years) from a single site in the Multicenter Orthopaedic Outcomes Network (MOON) nested cohort at minimum 2 years post BTB ACLR. Harvesting the patellar block for the BTB autograft was performed using an oscillating saw with a narrow blade, being careful not to extend the cut into the posterior cortex of the patella, and with gentle elevation of the bone block with an osteotome. MRI was performed at 3T (Philips, Achieva) and the imaging protocol included intermediate-weighted sagittal turbo spin-echo (TSE) imaging, axial and coronal fat-saturated TSE imaging, and 3D coronal gradient echo imaging. Structural MRI assessment of the knees was performed using the MRI Osteoarthritis Knee Score (MOAKS) semi-quantitative scoring system by a board-certified musculoskeletal radiologist. The prevalence of cartilage defects in each knee compartment (medial, lateral, patellofemoral), meniscal tears (medial, lateral; yes/no), bone marrow edema-like lesions (BMEL; medial, lateral, patellofemoral; yes/no), effusion (yes/no) and Hoffa synovitis (yes/no) were compared between the reconstructed and contralateral uninjured knees. Hypothesis testing was performed for the PF joint using a logistic regression model where the dependent variable was presence/absence of cartilage loss and the independent variable was knee status (surgical or contralateral).Results:There were no significant differences in the prevalence of cartilage defects (any lesions or full thickness loss) in the PFJ between the surgical BTB ACLR knees and the uninjured non-operative contralateral control knees. 38.3% of BTB ACLR knees had PFJ cartilage defects versus 31.7% of contralateral control knees with PFJ cartilage defects (p>0.05) (Table 1). The BTB ACLR knees had more cartilage defects in the medial and lateral tibiofemoral compartments, more meniscal tears, BMEL, effusion and Hoffa synovitis, than the contralateral knees. Figure 1 shows examples of PFJ cartilage defects on MRI for the reconstructed and contralateral uninjured knees. At 2 years follow-up, KOOS symptoms, sports, pain, and activities of daily living scores were maintained at a high level ranging from 88-98.Conclusion:Although prior studies suggest BTB ACLR increases the risk of PFJ OA, the current study shows no difference in MRI signs of early PTOA in the PFJ. Cartilage defects comparing reconstructed vs. contralateral uninjured knees 2 years after surgery based on MRI were not different. These results should be used in shared decision making with athletes in choosing the appropriate autograft during reconstruction. Future studies will investigate the influence of cartilage defects found in the medial and lateral compartments further.

Patient-Reported and Quantitative Outcomes of Anatomic Anterior Cruciate Ligament Reconstruction With Hamstring Tendon Autografts

Background:The pivot-shift test has become more consistent and reliable and is a meaningful outcome measurement after anterior cruciate ligament reconstruction (ACLR).Purpose/Hypothesis:The purpose of this investigation was to assess patient-reported outcomes (PROs) and the quantitative pivot shift (QPS) preoperatively, at time zero immediately after anatomic ACLR, and after 24 months as well as the relationship between PROs and the QPS. It was hypothesized that anatomic ACLR would restore rotatory stability measured by the pivot-shift test and that QPS measurements would be positively correlated with PROs.Study Design:Cohort study; Level of evidence, 2.Methods:The ACL-injured and contralateral uninjured knees from 89 of 107 (83.2%) enrolled patients at 4 international centers were evaluated using a standardized pivot-shift test. Tibial acceleration was assessed with an inertial sensor, and lateral compartment translation was measured using an image analysis system preoperatively, at time zero immediately postoperatively, and at follow-up after 2 years. PROs were assessed at 12 and 24 months postoperatively with the International Knee Documentation Committee (IKDC) subjective knee form, Cincinnati Knee Rating System (CKRS), Marx activity rating scale, and activity of daily living score (ADLS).Results:The mean patient age at surgery was 27 years (range, 15-45 years). A positive pivot shift preoperatively (side-to-side difference in tibial acceleration, 2.6 ± 4.0 m/s2; side-to-side difference in anterior tibial translation, 2.0 ± 2.0 mm) was reduced at time zero postoperatively (side-to-side difference in tibial acceleration, –0.5 ± 1.3 m/s2; side-to-side difference in anterior tibial translation, –0.1 ± 1.0 mm). All PROs improved from preoperatively to final follow-up at 24 months: from 56.5 to 85.5 points for the IKDC (P = .0001), from 28.8 to 32.4 points for the CKRS (P = .04), from 11.2 to 7.9 points for the Marx (P < .0001), and from 75.7 to 91.6 points for the ADLS (P < .0001). Neither preoperative nor time zero postoperative rotatory laxity assessed by the pivot-shift test correlated with PROs at 24-month follow-up. A graft retear was observed in 4 patients (4.5%) within 2 years of follow-up.Conclusion:Anatomic ACLR resulted in significantly improved and acceptable PROs at 2-year follow-up and a low failure rate. Anatomic ACLR restored QPS measurements of anterior tibial translation and tibial acceleration to those of the contralateral knee immediately after surgery while still under anesthesia, but there was no correlation between the QPS preoperatively or at time zero after ACLR and PROs at 2-year follow-up.

Proprioception deficiency in articular cartilage lesions of the knee

ABSTRACTPurposeThe purpose of this study is to investigate the proprioceptive function of patients with isolated articular cartilage lesions of the knee as compared to normal controls.MethodsThe Cartilage group consisted of eight subjects with radiologically and arthroscopically confirmed, isolated, unilateral, articular cartilage lesions of the knee (Outerbridge grade III or IV). They were compared to 50 normal controls. Knee proprioception was assessed by dynamic postural stabilometry using the Biodex Balance SD System. Patient-reported outcome measures (PROMs) were used to evaluate all subjects.ResultsProprioception of the injured knee of the Cartilage group was significantly poorer compared to that of the control group (p < 0.001). A significant proprioceptive deficit also was observed when the uninjured knees of the Cartilage group were compared to those in the Control group (p = 0.003). There was no significant proprioceptive difference between the injured and the contra-lateral uninjured knee of the Cartilage group (p = 0.116). A significant correlation was found between the proprioception measurements of the injured and uninjured knee of the Cartilage group (r = 0.76, p = 0.030). A significant difference was observed in all PROMs (p < 0.001) between the Cartilage and Control groups.ConclusionsPatients with isolated articular cartilage lesions of the knee had a significant proprioceptive deficit as compared to normal controls. The deficiency was profound and even affected the proprioceptive function of the contra-lateral uninjured knee. This study has shown that articular cartilage lesions have a major influence on knee proprioception. However, it remains uncertain as to whether a proprioceptive deficit leads to osteoarthritis or is a consequence of it.

Modified Iliotibial Band Tenodesis Is Indicated to Correct Intraoperative Residual Pivot Shift After Anterior Cruciate Ligament Reconstruction Using an Autologous Hamstring Tendon Graft: A Prospective Randomized Controlled Trial

Background: The indications for the addition of anterolateral soft tissue augmentation to anterior cruciate ligament (ACL) reconstruction and its effectiveness remain uncertain. Purpose: To determine if modified iliotibial band tenodesis (MITBT) can improve clinical outcomes and reduce the recurrence of ACL ruptures when added to ACL reconstruction in patients with a residual pivot shift. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: Patients with a primary ACL rupture satisfying the following inclusion criteria were enrolled: first ACL rupture, involved in pivoting sports, skeletally mature, no meniscal repair performed, and residual pivot shift relative to the contralateral uninjured knee immediately after ACL reconstruction. Patients were randomized to group A (no further surgery) or group B (MITBT added) and were followed up for 2 years. The patient-reported outcome (PRO) measures used were the International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS) subscale of sport/recreation (Sport/Rec), KOOS subscale of quality of life (QoL), Lysholm knee score (LKS), Tegner activity scale (TAS), recurrent ACL ruptures, or need for further surgery in either knee. Analysis of variance was used to compare PROs; the Wilcoxon test was used for the TAS; and the chi-square test was used for recurrence of ACL ruptures, meniscal injuries, and contralateral ACL ruptures (P < .05). Results: A total of 55 patients were randomized: 27 to group A (female:male ratio = 15:12; mean age, 22.3 ± 3.7 years) and 28 to group B (female:male ratio = 17:11; mean age, 21.8 ± 4.1 years). At 2-year follow-up, group A had a similar IKDC score (90.9 ± 10.7 vs 94.2 ± 11.2; respectively; P = .21), lower KOOS Sport/Rec score (91.5 ± 6.4 vs 95.3 ± 4.4, respectively; P = .02), similar KOOS QoL score (92.0 ± 4.8 vs 95.1 ± 4.3, respectively; P = .14), lower LKS score (92.5 ± 4.8 vs 96.8 ± 8.0, respectively; P = .004), lower TAS score (median, 7 [range, 7-9] vs 8 [range, 8-10], respectively; P = .03), higher rate of recurrence (14.8% vs 0.0%, respectively; P < .001), similar rate of meniscal tears (14.8% vs 3.6%, respectively; P = .14), and similar rate of contralateral ACL ruptures (3.7% vs 3.6%, respectively; P = .99) relative to group B. Conclusion: The augmentation of ACL reconstruction with MITBT reduced the risk of recurrent ACL ruptures in knees with a residual pivot shift after ACL reconstruction and improved KOOS Sport/Rec, LKS, and TAS scores. Registration: ACTRN12618001043224 (Australian New Zealand Clinical Trials Registry)

Synovial Fluid Biomarker Concentrations in Knees with Symptomatic Meniscus Injury Compared to Asymptomatic Contralateral Knees

Objectives: Changes in the joint microenvironment following an intra-articular injury have been implicated in the pathogenesis of knee osteoarthritis. Few studies have evaluated alterations in the joint microenvironment in the setting of meniscus injury. The purpose of the current study was to determine the changes in synovial fluid biomarker concentrations caused by meniscus pathology by comparing samples from injured, symptomatic knees to samples from asymptomatic contralateral knees. Methods: Patients undergoing surgery for unilateral meniscus injury were prospectively enrolled in this institutional review board approved study from October 2011 to December 2016. A cohort was formed consisting of patients that had synovial fluid samples collected from both the injured and contralateral uninjured knee at the time of arthroscopic surgery. Patients with ligamentous injury of the knee were excluded from the current analysis. Synovial fluid samples were collected just prior to incision and the concentrations of 10 biomarkers of interest were determined using a multiplex magnetic bread immunoassay. Results: The current analysis included synovial fluid samples from 82 knees (41 operative and 41 contralateral knees) from 41 patients undergoing arthroscopic surgery to treat a symptomatic meniscus injury. The mean age of patients was 49.86 +/- 11.75 years. Based on linear mixed effects models, there were significantly greater concentrations of 4 of the 5 pro-inflammatory biomarkers in symptomatic knees compared to asymptomatic knees when controlling for the duration of symptoms, BMI, age, and the random effects of by-patient variability. Knees with symptomatic meniscus injuries had 126.8 times greater concentration of IL-6, 2.7 times greater concentration of MCP-1, 2.0 times greater concentration of MIP-1beta, and 5.4 times greater concentration of MMP-3 compared to the contralateral, asymptomatic knee (Table 1). When controlling for the chronicity of the injury, presence of synovitis, and age of the patient, knees with concomitant high-grade cartilage lesions (ICRS 3 or 4) were associated with 2.1 times greater concentration of MCP-1, 1.9 times greater concentration of MIP-1beta, and 3.4 times greater concentration of VEGF compared to knees with concomitant low-grade cartilage lesions (ICRS 1 or 2). When controlling for the other variables, the presence of synovitis was associated with an 89.5% lower concentration of TIMP-1 compared to operative knees without synovitis. The age of the patient was found to affect the concentrations of IL-6, MCP-1, and VEGF. For all knees included in the study, each 1 year increase in age was associated with a 6% increase in IL-6, 3% increase in MCP-1, and 4% increase in VEGF (Figure 1). Conclusion: This study is the first that examines the synovial fluid biomarker concentrations in the setting of a symptomatic isolated meniscus injury. We demonstrated that 4 of the 5 proinflammatory biomarkers that were tested are found in greater concentration in the symptomatic knee. Furthermore, we described the effects of associated cartilage damage, synovitis, and patient age on biomarker concentrations. Understanding the implication of these alterations in the intra-articular microenvironment in the setting of meniscal pathology may hold the key to identifying treatment targets in an effort to prevent the onset of post-meniscectomy osteoarthritis. [Table: see text]

Lever sign test: is it sensitive for the diagnosis of anterior cruciate ligament disruption?

Background: Anterior cruciate ligament (ACL) tear is a common knee injury with various manual tests used for clinical diagnosis. The aim of this prospective study was to evaluate the lever sign test sensitivity as a new clinical test for diagnosis of ACL disruptions compared to other manual diagnostic tests. Methods: One hundred patients with chronic ACL tears were included in this study between January 2017 and March 2018. The mean age was 29.1±8.2 yr. Four clinical tests (anterior drawer, Lachman test, pivot shift, and lever sign) were obtained in all patients by two different clinicians. The contralateral uninjured knees were used as controls for comparison. The sensitivity of these tests was estimated with recording of the interobserver reliability for lever sign test. Statistically significant differences between the lever test and other clinical tests were assessed using chi-square analysis. Results: The recorded sensitivities of anterior drawer, pivot-shift, and Lachman tests were 82%, 88%, and 91%, respectively. The sensitivity of the lever sign test was much lower (34%) with 100% interrater reliability. There was a statistically significant difference between the lever sign test and other physical tests (P-value&lt;0.05). Conclusions: The lever sign test has much lower sensitivity than other clinical diagnostic tests in patients with chronic ACL lesions. More biomechanical studies should be carried out to prove the validity of this test for the diagnosis of ACL injuries. Level of evidence: Level III.

High Prevalence of Anterolateral Ligament Abnormalities on MRI in Knees With Acute Anterior Cruciate Ligament Injuries: A Case-Control Series From the SANTI Study Group.

Background:Broad variation in the reported rate of magnetic resonance imaging (MRI)–detected abnormalities of the anterolateral structures of the anterior cruciate ligament (ACL)–injured knee suggests a lack of reliability that has limited the use of MRI in clinical decision making.Purpose/Hypothesis:The aim of this study was to use MRI to determine the prevalence and spectrum of abnormalities of the anterolateral structures in acute ACL-injured knees, using the contralateral uninjured knee as a reference. We hypothesized that MRI evaluation of the acutely injured knee (using the uninjured knee as a reference) would allow reliable identification of abnormalities of the anterolateral structures.Study Design:Cohort study (diagnosis); Level of evidence, 3.Methods:Patients with acute ACL injury underwent MRI scan of both knees. Images were evaluated by 3 observers. Inter- and intraobserver reliabilities were determined for MRI parameters of anterolateral ligament (ALL) injury by use of the kappa (κ) test. Univariate and multivariate analyses were conducted to test associations between ALL abnormality and associated injuries.Results:A total of 34 patients were evaluated. Of these, 30 patients (88.2%) had at least 1 ALL abnormality in the ACL-injured knee (increased signal: n = 27[79.4%]; increased thickness: n = 15[44.1%]; tapering: n = 7[20.6%]; irregularities in the path of the ALL fibers: n = 21[61.7%]). Asymmetries of the genicular vessels were observed in 21 patients (61.7%). ALL abnormality was significantly associated with lateral joint capsular tears (P < .001). No correlation was found between ALL lesions and iliotibial band lesions (P = .49). Inter- and intraobserver reliabilities were very good concerning ALL signal changes and femoral and tibial bone bruises (κ coefficient, 0.81-1).Conclusion:MRI evaluation of the ALL was associated with good and very good inter- and intraobserver reliabilities, and it demonstrated abnormalities of the ALL in the majority of acutely ACL-injured knees. The index of suspicion for ALL injury should be elevated by the presence of lesions of the lateral capsule. This suggests that the ALL is part of a wider area of the lateral capsule that is often injured simultaneously in an acute ACL tear.

Restoring Condylar Width: Radiographic Relationship Between the Lateral Tibial Plateau and Lateral Femoral Condyle in Normal Adult Knees.

We hypothesized that a constant radiographic relationship exists between the lateral tibial and femoral condyles and that no side-to-side variation exists. We reviewed anteroposterior x-rays of 217 uninjured adults ages 18-65, Included 109 unilateral and 108 bilateral radiographs with no or minimal osteoarthrosis (Kellgren-Lawrence grades 0-1). The perpendicular distance between the lateral-most margins of the tibial plateau articular surface (A) and the lateral femoral epicondyle (B) and the lateral femoral condyle articular surface (C) was measured in millimeters (mm). Medial and lateral measurements to point (A) were recorded as (-) and (+), respectively. First, the average of measured distances in all unilateral knees and randomly selected either right or left knees from the bilateral group (n = 217) was calculated. Comparison was made between both sexes. Next, A-B and A-C distances were compared between right and left knees in the bilateral group (n = 108) to find any significant difference (2-tailed t test, alpha = 0.05). The average A-B distance was 0.60 ± 2.40 mm (-4.82 to +6.49 mm). The mean A-C distance was -3.96 ± 2.07 mm (-8.51 to +3.98 mm). No significant difference was found between A-B and A-C distances between males (0.40 ± 2.62 mm and -3.91 ± 2.05 mm) and females (0.70 ± 2.28 mm and -3.99 ± 2.09 mm). Similarly, no significant difference was found between A-B and A-C distances between right (1.08 ± 2.31 mm and -3.90 ± 1.73 mm) and left knees (0.90 ± 2.38 mm and -4.31 ± 1.7 mm). Concordance coefficient for interobserver and intraobserver reliability showed substantial agreement. In conclusion, this study provided a "normal" range for the relationship of the proximal lateral tibial plateau relative to the lateral femoral condyle. The lateral femoral epicondyle is generally aligned with the lateral tibial articular margin. The relationship between the lateral tibial plateau, lateral femoral epicondylar surface, and lateral femoral articular surface is constant from side to side. This technique is reproducible in the setting of fracture, and templating off of the contralateral uninjured knee may be beneficial in tibial plateau fracture surgery.

THE PHYSEAL-SPARING COMBINED EXTRA-/INTRA-ARTICULAR ILIOTIBIAL BAND ACL RECONSTRUCTION IN CHILDREN: A LONG-TERM STRENGTH, BALANCE, AND FUNCTIONAL ANALYSIS

Background: While ACL reconstruction (ACLR) in skeletally immature patients was traditionally delayed until physeal closure, the development of techniques that avoid physeal disturbance have allowed surgical intervention with minimization of growth compromise. Previous reports have shown excellent patient outcomes and functional stability with low re-tear rates at short and mid-term follow-up in one of the most widely used physeal-sparing techniques, the combined extra-articular/intra-articular modified-MacIntosh ACL reconstruction with Iliotibial band autograph (ACLR-ITB). However, there is a lack of evidence regarding the kinematic performance of the reconstruction, which has been referred to as ‘non-anatomic’, as well as the effect of time on function and effectiveness. This component of a single-site, prospective, cross-sectional study of ACLR-ITB patients at different times following their reconstruction, between 1 and 20 years post-operatively, was designed to compare the sports performance-based features of the ACLR-ITB knee to the contralateral, uninjured contralateral knee, including strength, dynamic balance, and functional hop testing, as well as patient-reported functional outcome measures and activity scores. The primary hypothesis is that similar function will be found, between the ACLR-ITB and Non-ACL of individuals, and that the degree of similarity will be maintained with increasing age, growth, and/or time from reconstruction. Methods: Patients who underwent an ACLR-ITB between 1-20 years prior to study initiation were identified from the surgical database of three high-volume surgeons at a tertiary care pediatric hospital. Exclusion criteria were major injury or surgery on the contralateral knee at any time point, or on the ACLR-ITB knee since the time of reconstruction. The resulting study cohort of 40 subjects participated in a single day of testing at a specialized sports injury prevention center. Evaluation consisted of isometric and isokinetic strength (quadriceps, hamstring, hip abductor, hamstring: quadriceps ratio), dynamic Y-balance, and single leg hop testing, with the limb symmetry index (LSI) tabulated to allow for comparisons between knees. Patient-reported functional outcomes and activity level were recorded by Pedi-IKDC and HSS-Pedi FABS questionnaires, respectively. For the comparisons between knees, the LSI values minus 100 were compared to 0 using the Wilcoxon signed rank test. Additionally, equivalence analysis using two one-sided paired t-tests was applied to further support comparison of the two limbs. The LSI-100 measures were tested to examine equivalency between the two limbs using a margin of equivalence of 8 (a difference less than 8 was not considered clinically important). The magnitude of the relationship between test results and time was assessed using Pearson correlation coefficients (r). Results: The 40 study subjects had a mean age of 10.6 years (range 6-14) at time of reconstruction and 18.0 years (range: 9-30) at time of testing. Time between ACLR and time of testing ranged from 1-17 years with 8 patients beyond 10 years (Table 1). Completed Pedi-IKDC and HSS-Pedi FABS resulted in mean scores of 96 (range: 79-100) and 22 (range 0-30), respectively. The outlier subject who reported an athletic activity level of ‘0’ attributed the low score to a busy career in construction. Mean LSI for the single leg hop was 99.2% (p=0.727) and 98.4% (p=0.045) for dynamic Y-balance. Of the isometric and isokinetic strength tests, the three major muscle groups (hip abductors (LSI: 97.9%, p=0.207), quadriceps (LSI: 97.9%, p=0.260) hamstring (LSI: 102.6%, p=0.264)) showed no significant differences. Hamstring to quadriceps ratio for both limbs showed a mean value of 0.5. The equivalence analysis of LSI minus 100 confirmed equivalency, that the measures for the two limbs are close enough so that the reconstructed limb cannot be considered superior or inferior to the native limb (all p&lt;0.05). No correlation between scores and time from reconstruction was observed, other than an expectable decline in HSS-Pedi FABS activity scores (r=-0.37, p=0.018) and improvement in hip abductor LSI (r=0.36, p=0.027) with increasing time from surgery. Conclusion / Significance: Similar to other long-term follow-up studies following ACLR, the current study demonstrated expectably decreasing activity with increasing patient age and time from ACLR-ITB. However, mean activity scores and functional outcome measures in this cohort are superior to age-based normative values, with outcome scores showing no decline in excellent knee function over time, up to 17 years following ACLR-ITB. Moreover, strength and functional hop testing show no clinically significant differences between the uninjured and reconstructed knees after at least 1 year, regardless of time from reconstruction. Equivalence in the measures between the two knees was shown for all LSI measures. The reported ‘non-anatomic’ features of the ACLR-ITB procedure do not appear to translate into clinically meaningful limitations in knee performance and function, which remain absent over time. Tables and figures: [Figure: see text]

Alterations in Synovial Fluid Biomarker Levels in Knees With Meniscal Injury as Compared With Asymptomatic Contralateral Knees

Background: Changes in the joint microenvironment after an injury to the articular surface of the knee have been implicated in the pathogenesis of osteoarthritis. While prior studies focused on changes in this microenvironment after anterior cruciate ligament ruptures, few have explored the biomarker changes that occur in the setting of meniscal injuries. Purpose: To determine whether meniscal injury results in significant alterations to synovial fluid biomarker concentrations as compared with noninjured contralateral knees. Additionally, to explore the relationship between synovial fluid biomarkers and the degree of cartilage injury seen in these patients. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients undergoing surgery for unilateral meniscal injury were prospectively enrolled from October 2011 to December 2016, forming a cohort that had synovial fluid samples collected from both the injured knee and the contralateral uninjured knee at the time of meniscal surgery. Synovial fluid samples were collected just before incision, and the concentrations of 10 biomarkers of interest were determined with a multiplex magnetic bead immunoassay. The concentrations of synovial fluid biomarkers from the operative and contralateral knees were compared. Additionally, the synovial fluid biomarker concentrations of operative knees from patients with associated high-grade cartilage lesions were compared with those with low-grade lesions. Results: The current analysis included synovial fluid samples from 82 knees (41 operative and 41 contralateral) from 41 patients undergoing arthroscopic surgery to treat a symptomatic meniscal injury. The mean ± SD age of patients was 49.86 ± 11.75 years. There were significantly greater concentrations of 4 of the 5 proinflammatory biomarkers (IL-6, MCP-1, MIP-1β, and MMP-3) in symptomatic knees as compared with asymptomatic knees when controlling for the duration of symptoms, body mass index, age, and the random effects of by-patient variability. In the injured knees, associated high-grade cartilage lesions were predictive of elevated MCP-1, MIP-1β, and VEGF levels. Low synovial fluid concentration of TIMP-1 or a greater ratio of MMP-3 to TIMP-1 was associated with the presence of synovitis. Increasing age was found to be an independent predictor of increased IL-6, MCP-1, and VEGF concentrations in the setting of symptomatic meniscal injury. Conclusion: The authors identified 4 proinflammatory synovial fluid biomarkers whose concentrations were significantly different after meniscal injury as compared with uninjured contralateral knees. Furthermore, they describe the effects of associated cartilage damage, synovitis, and patient age on biomarker concentrations.

Posterior tibial slope angle is associated with flexion-type Salter-Harris II and Watson-Jones type IV fractures of the proximal tibia.

Flexion-type Salter-Harris (SH) II fractures of the proximal tibia, also described as Watson-Jones (WJ) IV fractures, are rare injuries reported among adolescent athletes who are close to skeletal maturity and remain elusive. Due to this classification disagreement, the various treatments range from nonoperative to operative types, and no previous studies have explained the mechanisms of injury or the source of the fracture forces. This retrospective matched case-control study aimed to identify radiological factors that are associated with the fracture forces and to elucidate the mechanisms of these injuries. Sixteen flexion-type SH II/WJ IV fractures of the proximal tibia in 12 adolescents (12 males, mean age of 14.6years) were retrospectively reviewed, and knee alignment on plain radiographs was assessed to compare the radiological outcomes of the operated knees (n = 7), nonoperated knees (n = 9), and uninjured contralateral knees (n = 8). The results were compared to healthy age- and sex-matched control subjects (n = 24 knees). With regard to the radiological outcomes, the posterior tibial slope angle (PTSA) was significantly greater in the nonoperated knees (19.0° ± 1.6°), operated knees (16.8° ± 1.3°), and uninjured knees (13.6° ± 1.3°) than in the healthy knees of the matched control subjects (9.6° ± 0.4°). The anatomical tibiofemoral angle was significantly less in the nonoperated knees (0.7° ± 0.6°) than in the healthy knees of the matched control subjects (3.7° ± 0.4°). These findings suggest a relationship between an increased PTSA and flexion-type SH II/WJ IV fractures of the proximal tibia, considering the deteriorating effects of an increased PTSA on knee kinematics. Adolescent active athletes with an increased PTSA and partially closed epiphysis of the proximal tibia are at risk for suffering from flexion-type SH II/WJ IV fractures of the proximal tibia until the closure of the proximal tibial epiphysis. Case-control study, Level III.

Non-operative treatment of ACL injury is associated with opposing subjective and objective outcomes over 20years of follow-up.

The aim of this study was the evaluation of long-term clinical and radiological outcomes of non-operative treatment of anterior cruciate ligament (ACL) deficiency. The hypothesis was that conservative treatment would be associated with a deterioration of subjective and objective measures of joint health and disability over time. From an initial sample of 41 patients conservatively treated for ACL rupture, 10 received secondary ACL reconstruction, 1 was excluded due to contralateral ACL injury, and 1 patient required total knee replacement and a high tibial osteotomy. Seven further patients were lost to follow-up. The remaining 21 patients (15 male, 6 female, mean age 53.1 ± 9.2years at the last follow-up) were evaluated by the same two examiners 5-7, 10-13 and 20-22years after the injury. The evaluation was based on objective and subjective scores, instrumented testing, radiographic examination and assessment of sports activity. While subjective patient satisfaction improved over time, objective scores stayed constant or deteriorated (radiologic evaluation). Instrumented knee laxity testing showed an initial tendency to increasing instability, followed by a decrease in anterior tibial translation in the second half of the observation period. Physical activity levels, particularly in high-risk sports, decreased significantly (p < 0.05) compared to preinjury levels. All patients developed significant arthritic degenerative changes over time compared to the uninjured contralateral knee. No correlation to activities in high- or low-risk pivoting sports was found. Patient satisfaction with conservative treatment of ACL injuries is good in spite of objective measures indicating increasing degenerative changes. IV.

Anterior Cruciate Ligament Reconstruction Affects Tibiofemoral Joint Congruency During Dynamic Functional Movement

Background: Anterior cruciate ligament reconstruction (ACLR) has been shown to alter kinematics, which may influence dynamic tibiofemoral joint congruency (a measure of how well the bone surfaces fit together). This may lead to abnormal loading of cartilage and joint degeneration. However, joint congruency after ACLR has never been investigated. Hypotheses: The ACLR knee will be more congruent than the contralateral uninjured knee, and dynamic congruency will increase over time after ACLR. Side-to-side differences (SSD) in dynamic congruency will be related to cartilage contact location/area and subchondral bone curvatures. Study Design: Descriptive laboratory study. Methods: The authors examined 43 patients who underwent unilateral ACLR. At 6 months and 24 months after ACLR, patients performed downhill running on a treadmill while synchronized biplane radiographs were acquired at 150 images per second. Dynamic tibiofemoral kinematic values were determined by use of a validated volumetric model-based tracking process that matched patient-specific bone models, obtained from computed tomography, to biplane radiographs. Patient-specific cartilage models, obtained from magnetic resonance imaging, were registered to tracked bone models and used to calculate dynamic cartilage contact regions. Principle curvatures of the subchondral bone surfaces under each cartilage contact area were calculated to determine joint congruency. Repeated-measures analysis of variance was used to test the differences. Multiple linear regression was used to identify associations between SSD in congruency index, cartilage contact area, contact location, and global curvatures of femoral or tibial subchondral bone. Results: Lateral compartment congruency in the ACLR knee was greater than in the contralateral knee (P < .001 at 6 months and P = .010 at 24 months). From 6 to 24 months after surgery, dynamic congruency decreased in the medial compartment (P = .002) and increased in the lateral compartment (P = .007) in the ACLR knee. In the lateral compartment, SSD in joint congruency was related to contact location and femur global curvature, and in the medial compartment, SSD in joint congruency was related to contact area. Conclusion: ACLR appears to affect dynamic joint congruency. SSD in joint congruency was associated with changes in contact location, contact area, and femoral bony curvature. Clinical Relevance: Alterations in tibiofemoral contact location, contact area, and bone shape affect dynamic joint congruency, potentially contributing to long-term degeneration after ACLR.

3D-Printed Patient-Specific ACL Femoral Tunnel Guide from MRI.

Background:Traditional ACL reconstruction with non-anatomic techniques can demonstrate unsatisfactory long-term outcomes with regards instability and the degenerative knee changes observed with these results. Anatomic ACL reconstruction attempts to closely reproduce the patient's individual anatomic characteristics with the aim of restoring knee kinematics, in order to improve patient short and long-term outcomes. We designed an arthroscopic, patient-specific, ACL femoral tunnel guide to aid anatomical placement of the ACL graft within the femoral tunnel.Methods:The guide design was based on MRI scan of the subject's uninjured contralateral knee, identifying the femoral footprint and its anatomical position relative to the borders of the femoral articular cartilage. Image processing software was used to create a 3D computer aided design which was subsequently exported to a 3D-printing service.Results:Transparent acrylic based photopolymer, PA220 plastic and 316L stainless steel patient-specific ACL femoral tunnel guides were created; the models produced were accurate with no statistical difference in size and positioning of the center of the ACL femoral footprint guide to MRI (p=0.344, p=0.189, p=0.233 respectively). The guides aim to provide accurate marking of the starting point of the femoral tunnel in arthroscopic ACL reconstruction.Conclusion:This study serves as a proof of concept for the accurate creation of 3D-printed patient-specific guides for the anatomical placement of the femoral tunnel during ACL reconstruction.

Patient-reported outcome measures following anterior cruciate ligament reconstruction are not related to dynamic knee extension angle

ObjectivesControversy still exists on whether knee hyperextension affects the outcome following anterior cruciate ligament reconstruction (ACL-R). Therefore, the purpose of the present study was to determine if maximum knee extension angle of ACL-R knees and contralateral uninjured knees during walking is related to the clinical outcome following ACL-R. It was hypothesised that maximum knee extension angle would not be significantly correlated with patient-reported outcome measures (PROMs) following ACL-R.MethodsForty-two patients (age at surgery: 23±9 years, 23 male and 19 female) underwent unilateral ACL-R. Twenty-four months after surgery, subjects performed level walking on a treadmill while biplane radiographs were acquired at 100 Hz. Three-dimensional tibiofemoral motion was determined using a validated model-based tracking process. Tibiofemoral rotations were calculated from foot strike through early stance. The primary kinematic outcome measure was maximum knee extension angle of ACL-R and contralateral uninjured knees during walking, with positive values indicating hyperextension. The side-to-side difference (SSD) in maximum knee extension angle was calculated by subtracting the angle of the contralateral uninjured knee from that of the ACL reconstructed knee. PROMs (International Knee Documentation Committee Subjective Knee Form, Knee Injury and Osteoarthritis Score and Marx Activity Rating Scale) were obtained at 24 months after surgery. Correlations between PROMs and maximum dynamic knee extension angle in ACL-R and contralateral knee were evaluated (P<0.05).ResultsMaximum knee extension angle during walking was 2.3±4.5° in ACL-R knees and 4.3±4.2° in contralateral uninjured knees at 24 months after surgery, indicating hyperextension during walking on average. SSD in maximum knee extension angle was −2.0±3.7°. No significant correlation was observed between maximum knee extension angle and the PROMs.ConclusionMaximum knee extension angle during walking was not significantly correlated with PROMs, suggesting that clinically, physiologic knee hyperextension can be restored after ACL-R and not adversely affect PROMs.Level of evidenceLevel III.

A comparison of patellofemoral cartilage morphology and deformation in anterior cruciate ligament deficient versus uninjured knees

Anterior cruciate ligament (ACL) deficient patients have an increased rate of patellofemoral joint (PFJ) osteoarthritis (OA) as compared to the general population. Although the cause of post-injury OA is multi-factorial, alterations in joint biomechanics may predispose patients to cartilage degeneration. This study aimed to compare in vivo PFJ morphology and mechanics between ACL deficient and intact knees in subjects with unilateral ACL ruptures. Eight male subjects underwent baseline MRI scans of both knees. They then performed a series of 60 single-legged hops, followed by a post-exercise MRI scan. This process was repeated for the contralateral knee. The MR images were converted into three-dimensional surface models of cartilage and bone in order to assess cartilage thickness distributions and strain following exercise. Prior to exercise, patellar cartilage was significantly thicker in intact knees as compared to ACL deficient knees by 1.8%. In response to exercise, we observed average patellar cartilage strains of 5.4 ± 1.1% and 2.5 ± 1.4% in the ACL deficient and intact knees, respectively. Importantly, the magnitude of patellar cartilage strain in the ACL deficient knees was significantly higher than in the intact knees. However, while trochlear cartilage experienced a mean strain of 2.4 ± 1.6%, there was no difference in trochlear cartilage strain between the ACL deficient and uninjured knees. In summary, we found that ACL deficiency was associated with decreased patellar cartilage thickness and increased exercise-induced patellar cartilage strain when compared to the uninjured contralateral knees.

A Prospective Evaluation of Femoral Tunnel Placement for Anatomic Anterior Cruciate Ligament Reconstruction Using 3-Dimensional Magnetic Resonance Imaging

Background: The recent emphasis on anatomic reconstruction of the anterior cruciate ligament (ACL) is well supported by clinical and biomechanical research. Unfortunately, the location of the native femoral footprint can be difficult to see at the time of surgery, and the accuracy of current techniques to perform anatomic reconstruction is unclear. Purpose: To use 3-dimensional magnetic resonance imaging (3D MRI) to prospectively evaluate patients with torn ACLs before and after reconstruction and thereby assess the accuracy of graft position on the femoral condyle. Study Design: Cohort study; Level of evidence, 3. Methods: Forty-one patients with unilateral ACL tears were recruited into the study. Each patient underwent 3D MRI of both the injured and uninjured knees before surgery. The contralateral (uninjured) knee was used to define the patient’s native footprint. Patients then underwent ACL reconstruction, and the injured knee underwent reimaging after surgery. The location and percentage overlap of the reconstructed femoral footprint were compared with the patient’s native footprint. Results: The center of the native ACL femoral footprint was a mean 12.0 ± 2.6 mm distal and 9.3 ± 2.2 mm anterior to the apex of the deep cartilage. The position of the reconstructed graft was significantly different, with a mean distance of 10.8 ± 2.2 mm distal (P = .02) and 8.0 ± 2.3 mm anterior (P = .01). The mean distance between the center of the graft and the center of the native ACL femoral footprint (error distance) was 3.6 ± 2.6 mm. Comparing error distances among the 4 surgeons demonstrated no significant difference (P = .10). On average, 67% of the graft overlapped within the native ACL femoral footprint. Conclusion: Despite contemporary techniques and a concerted effort to perform anatomic ACL reconstruction by 4 experienced sports orthopaedic surgeons, the position of the femoral footprint was significantly different between the native and reconstructed ACLs. Furthermore, each surgeon used a different technique, but all had comparable errors in their tunnel placements.