Anteroposterior Tibial Translation Research Articles

Bicruciate lesion biomechanics, Part1-Diagnosis: translations over 15mm at 90° of knee flexion are indicative of a complete tear.

Understanding the pathomechanics of a bicruciate injury (BI) is critical for its correct diagnosis and treatment. The purpose of this biomechanical study aims to quantify the effects of sequential sectioning of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL)bundles on knee laxity. Twelve cadaveric knees (six matched pairs) were used. Knee laxity measurements consisted of neutral tibial position, anterior-posterior translation, internal-external rotation, and varus-valgus angulation in different conditions: intact, ACL cut, incomplete BI (divided into two groups: anterolateral (AL) bundle intact or posteromedial (PM) bundle intact) and complete bicruciate tear. Data were collected using a Microscribe system at 0°, 30°, 60°, and 90° of knee flexion. In comparison to the intact knees, incomplete BI and complete BI showed a significant increase of total antero-posterior tibial translation. The largest significant increase was observed at 90° of flexion after a complete bicruciate resection (p < 0.001). A threshold difference greater than 15mm from the intact could be used to identify a complete BI from an incomplete BI evaluating the total antero-posterior translation at 90°. All sectioned states had significant increases compared with the intact condition in internal-external rotation and varus-valgus stability at all tested flexion angles. Both incomplete and complete BI led to an important AP translation instability at all angles; however, full extension was the most stable position at all injured models. Total antero-posterior translation at 90° of knee flexion over 15mm, in comparison to the intact condition, was indicative of a complete BI. Since the appropriate assessment of a combined ACL and PCL lesion remains a challenge, this study intends to assist its diagnosis. As BI's main antero-posterior instability occurred at 90°, a total antero-posterior drawer test is proposed to evaluate BI in the clinical setting. Total antero-posterior translation at 90° > 15mm, in comparison to the intact condition or the contra-lateral non-injured knee, can be used to identify a complete from an incomplete BI.

Factors associated with the status of meniscal tears following meniscal repair concomitant with anterior cruciate ligament reconstruction

ABSTRACTPurpose: Anterior cruciate ligament (ACL) injuries are often accompanied by meniscal tears. Meniscal repair is typically performed during ACL reconstruction. However, retear of the meniscus after repair is frequent. The purpose of this study was to analyze the factors associated with meniscal healing after meniscal repair concomitant with ACL reconstruction. Materials and methods: Eighty-seven meniscal repairs in 87 patients who received meniscal repair combined with ACL reconstruction and received second-look arthroscopy at a mean of postoperatively 15.7 months were examined retrospectively. The menisci were divided into three groups (complete heal, incomplete heal, and retear), and factors thought to affect the healing status of repaired menisci were analyzed using multivariate logistic regression analysis. Results: Meniscal healing was judged to be complete in 49 knees (56%), incomplete in 19 knees, (22%), and retear in 19 knees (22%). There were no significant differences among the three groups in age, sex, time from injury to operation, mean Tegner activity scale, tear location, or mean postoperative anteroposterior tibial translation on KT-1000. The mean length of the tear was significantly higher in the retear group. Additionally, the proportion patients with complete tear and the proportion with postoperative positive pivot shift test were significantly higher in the retear group than in the other groups. Multivariate logistic regression analysis showed that complete tear and positive pivot shift test were associated with retear. Conclusions: These findings suggest that complete tears and residual instability are associated with retears after meniscal repair concomitant with ACL reconstruction.

Functional outcome after transphyseal anterior cruciate ligament reconstruction in young patients with open growth plates

BackgroundThis study evaluates sports ability, rotational laxity and potential growth changes in children after transphyseal ACL reconstruction with metaphyseal fixation technique, considering physis biology by placing drill holes vertically in the femoral anatomic origin in order to reduce volumetric injury to the physis. MethodsIn this retrospective trial of 42 patients data were collected. Thirty-seven were reviewed measuring rotational laxity and anteroposterior tibial translation using the Laxitester (ORTEMA Sport Protection, Markgroeningen, Germany) and the KT1000. Clinical examination was evaluated with the IKDC 2000 knee examination form. Leg axis was determined with digital photography and leg length was assessed clinically. Sports ability was assessed with questionnaires including subjective IKDC, Tegner Activity Scale, Activity Rating Scale and a questionnaire on sports and level of sports. ResultsMean follow-up was 24.9months. Mean age at surgery was 13.2years in boys and 13.1years in girls. IKDC 2000 grading was A or B in 28 patients and C in nine patients. Significant increased anterior tibial translation was observed in neutral position and in external tibia rotation. No growth abnormalities were seen. Fifty-seven percent of the patients were able to participate in competitive sports at follow-up. ConclusionTransphyseal ACL reconstruction with metaphyseal fixation in children with open growth plates can be done with low risk of growth changes. Return to competitive sports is possible although low rotational laxity still exists. Level of evidenceIV.

Surgical treatment of anterior cruciate ligament avulsion injuries in skeletally immature patients by cerclage wire loop technique

Introduction Tibial eminence avulsion fracture is the pediatric equivalent to a midsubstance anterior cruciate ligament (ACL) injury. It is most common between the ages of 8 and 19 years. Patients and methods From June 2009 to December 2012, 26 patients with ACL avulsion fractures were submitted to surgical treatment by means of a cerclage stainless steel wire loop. Seventeen patients were male and nine were female. Their ages ranged from 8 to 15 (mean: 12) years, and they were followed up for 6–22 (mean: 16) months. Results The Meyers & McKeever and Zaricznyj classifications were used for evaluating fractures for surgery. Radiographs in two views are often sufficient to establish a diagnosis. Cases were evaluated clinically by means of the anterior drawer test, which was negative in 21 patients, whereas four patients had residual laxity of about 2–3 mm increased manual anteroposterior tibial translation compared with the contralateral knee, without subjective feeling of instability. According to the Lyslholm scoring system excellent and good results were achieved in 24 (92%) cases, two patients showed fair results, and there were no poor results. Conclusion The use of a stainless steel wire loop cerclage by open technique gives excellent results, with benefits such as capture and control tension on ACL on each side of the avulsed fragment proper and adequate mechanical strength.

No difference in osteoarthritis after surgical and non-surgical treatment of ACL-injured knees after 10years.

Aim of this study was to record and compare the functional and activity level as well as the manifestations of osteoarthritis after isolated ACL ruptures between patients with conservative treatment and ACL reconstruction with hamstrings tendon graft. Thirty-two patients diagnosed with ACL rupture were recorded. Clinical examination included the Tegner and Lysholm activity scale, the International Knee Documentation Committee Subjective Form and KT-1000 arthrometer. Narrowing of the medial and lateral joint spaces was assessed using the IKDC knee examination score. Median follow-up was 10.3years (range 10-11). Fifteen patients were conservatively treated (median age 33years, range 25-39). Seventeen patients were operated (median age 31years, range 20-36). There was significant difference between the mean values of IKDC scores in favour of the ACL-reconstruction group of patients, 86.8 (SD 6.5) versus 77.5 (SD 13.8), respectively (p=0.04). The mean value of anteroposterior tibial translation was 1.5mm (SD 0.2) for ACL-reconstruction group of patients, while the corresponding mean value for ACL-conservative group was 4.5mm (SD 0.5), p=0.03. Four patients in ACL-reconstruction group had radiological findings of grade C or D according to IKDC form. In ACL-conservative group, five patients presented similar signs (n.s.). ACL reconstruction using hamstrings autograft resulted in better functional outcome and laxity measurements than ACL-conservative management. However, the incidence of radiological osteoarthritis was similar between the two groups and independent on the pre-operative grade of laxity and functional status of the patients. Equally, bone bruises were not found as a risk factor for the development of osteoarthritis after ACL rupture. Prospective randomized study, Level II.

Non-invasive, non-radiological quantification of anteroposterior knee joint ligamentous laxity

ObjectivesWe performed in vitro validation of a non-invasive skin-mounted system that could allow quantification of anteroposterior (AP) laxity in the outpatient setting.MethodsA total of 12 cadaveric lower limbs were tested with a commercial image-free navigation system using trackers secured by bone screws. We then tested a non-invasive fabric-strap system. The lower limb was secured at 10° intervals from 0° to 60° of knee flexion and 100 N of force was applied perpendicular to the tibia. Acceptable coefficient of repeatability (CR) and limits of agreement (LOA) of 3 mm were set based on diagnostic criteria for anterior cruciate ligament (ACL) insufficiency.ResultsReliability and precision within the individual invasive and non-invasive systems was acceptable throughout the range of flexion tested (intra-class correlation coefficient 0.88, CR 1.6 mm). Agreement between the two systems was acceptable measuring AP laxity between full extension and 40° knee flexion (LOA 2.9 mm). Beyond 40° of flexion, agreement between the systems was unacceptable (LOA > 3 mm).ConclusionsThese results indicate that from full knee extension to 40° flexion, non-invasive navigation-based quantification of AP tibial translation is as accurate as the standard validated commercial system, particularly in the clinically and functionally important range of 20° to 30° knee flexion. This could be useful in diagnosis and post-operative evaluation of ACL pathology.Cite this article: Bone Joint Res 2013;2:233–7.

Differences in Knee Kinematics Between Awake and Anesthetized Patients During the Lachman and Pivot-Shift Tests for Anterior Cruciate Ligament Deficiency

Background:The Lachman and pivot-shift tests have been widely used for detecting anterior cruciate ligament (ACL) deficiency. However, it still remains unclear whether these manual tests can be quantified accurately while patients are awake.Purpose:To assess the differences in knee kinematics of awake and anesthetized patients.Study Design:Case series; Level of evidence, 4.Methods:A total of 50 patients with unilateral ACL rupture were examined. Anteroposterior tibial translation was assessed using a KT-1000 arthrometer at maximal manual power. Anterior tibial translations during the manual Lachman test and the acceleration of tibial posterior translation (APT) during the pivot-shift test were also measured using an electromagnetic measurement system (EMS). All 3 measurements were performed on the day previous to surgery while the patients were awake and on the operative day before the surgery while the patients were under general anesthesia.Results:The mean side-to-side difference in anteroposterior tibial translation was 5.6 ± 2.6 mm in the awake state and 5.9 ± 3.5 mm under anesthesia, indicating a nonsignificant difference. According to the EMS, the mean side-to-side difference in anteroposterior tibial translation during the Lachman test was 4.6 ± 3.6 mm in the awake state and 6.9 ± 4.3 mm under anesthesia, indicating a significant difference (P < .01). The mean APT during the pivot-shift test was −0.8 ± 0.3 m/s2 in intact knees and −1.1 ± 0.4 m/s2 in ACL-deficient knees when the patients were awake and was −0.7 ± 0.2 m/s2 and −1.7 ± 1.0 m/s2, respectively, when the patients were under anesthesia. In ACL-deficient knees, the APT pivot-shift test result was significantly higher when the patients were under anesthesia than when they were awake (P < .01).Conclusion:In ACL-deficient knees, the knee kinematics during the Lachman and pivot-shift tests is significantly affected by patient consciousness, and caution is needed in quantifying anterior knee laxity during these tests when the patients are awake.

Biomechanical consequences of PCL deficiency in the knee under simulated muscle loads—an in vitro experimental study

The mechanism of chronic degeneration of the knee after posterior cruciate ligament (PCL) injury is still not clearly understood. While numerous biomechanical studies have been conducted to investigate the function of the PCL with regard to antero-posterior stability of the knee, little has been reported on its effect on the rotational stability of the knee. In this study, eight cadaveric human knee specimens were tested on a robotic testing system from full extension to 120° of flexion with the PCL intact and with the PCL resected. The antero-posterior tibial translation and the internal–external tibial rotation were measured when the knee was subjected to various simulated muscle loads. Under a quadriceps load (400 N) and a combined quadriceps/hamstring load (400/200 N), the tibia moved anteriorly at low flexion angles (below 60°). Resection of the PCL did not significantly alter anterior tibial translation. At high flexion angles (beyond 60°), the tibia moved posteriorly and rotated externally under the muscle loads. PCL deficiency significantly increased the posterior tibial translation and external tibial rotation. The results of this study indicate that PCL deficiency not only changed tibial translation, but also tibial rotation. Therefore, only evaluating the tibial translation in the antero-posterior direction may not completely describe the effect of PCL deficiency on knee joint function. Furthermore, the increased external tibial rotations were further hypothesized to cause elevated patello-femoral joint contact pressures. These data may help explain the biomechanical factors causing long-term degenerative changes of the knee after PCL injury. By fully understanding the etiology of these changes, it may be possible to develop an optimal surgical treatment for PCL injury that is aimed at minimizing the long-term arthritic changes in the knee joint.

Anteroposterior tibial translation during simulated isometric quadriceps contractions

The anteroposterior tibial translations cause by simulated isometric quadriceps forces of up to 750 N were measured in vitro for two extension-restraining load placements at five flexion angles. Both quadriceps force and tibial translation were flexion-angle and load-placement dependent. Quadriceps force was linearly dependent on restraining force; tibial displacement was either very small (<1 mm) or increased non-linearly with increasing restraining force. The measured directions of tibial translation agreed with the predictions of a sagittal-plane knee model. From the displacement data, the directions and axes of tibial rotation were deduced.