Rotational instability of the knee: internal tibial rotation under a simulated pivot shift test.

INTRODUCTION: Recently, several publications investigated the rotational instability of the human knee joint under pivot shift examinations and reported the internal tibial rotation as measurement for instrumented knee laxity measurements. We hypothesize that ACL deficiency leads to increased internal tibial rotation under a simulated pivot shift test. Furthermore, it was hypothesized that anatomic single bundle ACL reconstruction significantly reduces the internal tibial rotation under a simulated pivot shift test when compared to the ACL-deficient knee. METHODS: In seven human cadaveric knees, the kinematics of the intact knee, ACL-deficient knee, and anatomic single bundle ACL reconstructed knee were determined in response to a 134 N anterior tibial load and a combined rotatory load of 10 N m valgus and 4 N m internal tibial rotation using a robotic/UFS testing system. Statistical analyses were performed using a two-way ANOVA test. RESULTS: Single bundle ACL reconstruction reduced the anterior tibial translation under a simulated KT-1000 test significantly compared to the ACL-deficient knee (P < 0.05). After reconstruction, there was a statistical significant difference to the intact knee at 30 degrees of knee flexion. Under a simulated pivot shift test, anatomic single bundle ACL reconstruction could restore the intact knee kinematics. Internal tibial rotation under a simulated pivot shift showed no significant difference in the ACL-intact, ACL-deficient and ACL-reconstructed knee. CONCLUSION: In conclusion, ACL deficiency does not increase the internal tibial rotation under a simulated pivot shift test. For objective measurements of the rotational instability of the knee using instrumented knee laxity devices under pivot shift mechanisms, the anterior tibial translation should be rather evaluated than the internal tibial rotation.

Effect of Ranolazine on Ischemic Myocardium IN Patients With Acute Cardiac Ischemia (RIMINI-Trial): A Randomized Controlled Pilot Trial.

BACKGROUND: Coronary artery disease is the most prevalent manifestation among cardiovascular diseases. Despite modern treatment, risk of ischemic complications in patients with acute coronary syndrome (ACS) remains important. The late Na+ current blocker ranolazine has shown to reduce the risk of recurrent ischemia and worsening of angina in patients with non-ST-segment elevation ACS by possibly improving myocardial perfusion, but up to now no trial has addressed whether this enhanced perfusion also leads to a decrease in ischemic myocardium of patients with ACS. We designed a pilot trial (Reduction of Ischemic Myocardium with Ranolazine-Treatment IN patients with acute myocardial Infarction, ClinicalTrials.gov Identifier: NCT01797484) for feasibility and proof of concept that a 6-week ranolazine add-on therapy would reduce the area of ischemic myocardium in patients with ACS. METHODS AND RESULTS: The trial was designed in a 2-armed, controlled and randomized way. Twenty participants with unstable angina, proof of acute cardiac ischemia, and myocardial dyskinesia by speckle-tracking echocardiography were included. Ten participants received the study drug ranolazine additionally to standard treatment. The control group received standard treatment without additional study medication. Speckle-tracking echocardiography was performed before coronary intervention, before the first dose of ranolazine, and after 6 weeks of ranolazine treatment. Ranolazine was administered safely during acute myocardial infarction. Speckle-tracking echocardiography proved to be suitable for evaluation of myocardial dyskinesia. Patients receiving ranolazine showed a trend to higher normal fraction of the cumulative global strain than patients in the standard treatment group (15% vs 11%). No major complications relating study medication were observed. CONCLUSION: In conclusion, in this preliminary hypothesis-driven study, 6-week ranolazine therapy was shown to decrease the area of dyskinetic myocardium in patients with ACS by trend. Global strain rate measurement using speckle-tracking echocardiography can be applied measuring those effects and is, compared to other techniques, safe and harmless. Our data provide a sound basis for a follow-up trial.

Effect of ranolazine on plasma arginine derivatives and urinary isoprostane 8-iso-PGF2α in patients with myocardial infarction in the randomized RIMINI-Trial.

The purpose of the present study was to assess whether 6-week ranolazine application on top of guideline-based treatment impacts on the arginine/NO pathway and urinary isoprostane 8-iso-PGF2α as marker of oxidative stress in patients directly after a myocardial infarction. 20 patients with unstable angina pectoris and proof of acute cardiac ischemia entered the study. 10 subjects received the study drug ranolazine in addition to standard treatment, the others received only standard treatment. Urine and venous blood were collected before and after treatment. At the end of the study and compared to baseline, homoarginine levels had increased in the control group. This was not the case in ranolazine-patients. Interestingly, in ranolazine-treated-patients arginine plasma levels were significantly higher at the end of the study than at baseline (difference +26 µmol/L, 95% CI 8.6 to 44 µmol/L). ADMA and SDMA levels were not different. Urine levels of the oxidative stress marker 8-iso-PGF2α tended to be lower in ranolazine-treated patients (-144 pmol/mg creatinine). Findings of this hypothesis-driven study give evidence that ranolazine treatment enhances arginine plasma levels and lowers oxidative stress.

Anatomical and nonanatomical double-bundle anterior cruciate ligament reconstruction: importance of femoral tunnel location on knee kinematics.

BACKGROUND: Studies have suggested that double-bundle anterior cruciate ligament reconstruction may restore intact knee kinematics better than single-bundle anterior cruciate ligament reconstruction. Although the tunnel position of the femoral anteromedial bundle is well established, the effects of different posterolateral bundle positions on knee kinematics are unknown. HYPOTHESIS: Double-bundle anterior cruciate ligament reconstruction with an anatomical (shallow) femoral posterolateral bundle tunnel placement will restore knee kinematics more closely than will a nonanatomical (deep) femoral posterolateral bundle tunnel position. STUDY DESIGN: Controlled laboratory study. METHODS: In 12 human cadaveric knees, the kinematics of the intact knee, anterior cruciate ligament-deficient knee, and double-bundle anterior cruciate ligament-reconstructed knees with nonanatomical femoral posterolateral tunnel placement and anatomical posterolateral bundle placement were determined in response to a 134-N anterior tibial load and a combined rotatory load of 10 N x m valgus and 4 N x m internal tibial rotation using a robotic/universal force moment sensor testing system. Statistical analyses were performed using a 2-way analysis of variance test. RESULTS: Double-bundle anterior cruciate ligament reconstruction with nonanatomical posterolateral bundle placement showed significantly higher anterior tibial translation under anterior tibial and combined rotatory load than did the intact knee at 0 degrees and 30 degrees of knee flexion (P < .05). Reconstruction with an anatomical posterolateral tunnel placement restored the intact knee kinematics and showed significantly lower anterior tibial translation under anterior tibial and combined rotatory load when compared with reconstruction with nonanatomical posterolateral placement (P < .05). CONCLUSION: Double-bundle anterior cruciate ligament reconstruction using the anatomical posterolateral bundle tunnel position restores the intact knee kinematics. A nonanatomical posterolateral bundle position results in rotatory instability. CLINICAL RELEVANCE: Double-bundle anterior cruciate ligament reconstruction should be performed using anatomical tunnel placement of the anteromedial and posterolateral bundles. Nonanatomical double-bundle reconstruction may fail to show any clinical superiority to single-bundle reconstruction and should be avoided.

Anterolateral rotational knee instability: role of posterolateral structures. Winner of the AGA-DonJoy Award 2006.

INTRODUCTION: The aim of this study was to determine the anterolateral rotational instability (ALRI) of the human knee after rupture of the anterior cruciate ligament (ACL) and after additional injury of the different components of the posterolateral structures (PLS). It was hypothesized that a transsection of the ACL will significantly increase the ALRI of the knee and furthermore that sectioning the PLS [lateral collateral ligament (LCL), popliteus complex (PC)] will additionally significantly increase the ALRI. MATERIALS AND METHODS: Five human cadaveric knees were used for dissection to study the appearance and behaviour of the structures of the posterolateral corner under anterior tibial load. Ten fresh-frozen human cadaver knees were subjected to anterior tibial load of 134 N and combined rotatory load of 10 Nm valgus and 4 Nm internal tibial torque using a robotic/universal force moment sensor (UFS) testing system and the resulting knee kinematics were determined for intact, ACL-, LCL- and PC-deficient (popliteus tendon and popliteofibular ligament) knee. Statistical analyses were performed using a two-way ANOVA test with the level of significance set at P < 0.05. RESULTS: Sectioning the ACL significantly increased the anterior tibial translation (ATT) and internal tibial rotation under a combined rotatory load at 0 and 30 degrees flexion (P < 0.05). Sectioning the LCL further increased the ALRI significantly at 0 degrees , 30 degrees and 60 degrees of flexion (P < 0.05). Subsequent cutting of the PC increased the ATT under anterior tibial load (P < 0.05), but did not increase the ALRI (P > 0.05). CONCLUSION: The results of the current study confirm the concept that the rupture of the ACL is associated with ALRI. Current reconstruction techniques should focus on restoring the anterolateral rotational knee instability to the intact knee. Additional injury to the LCL further increases the anterior rotational instability significantly, while the PC is less important. Cautions should be taken when examining a patient with ACL rupture to diagnose injuries to the primary restraints of tibial rotation such as the LCL. If an additional extraarticular stabilisation technique is needed for severe ALRI, the technique should be able to restore the function of the LCL and not the PC.