Although both techniques provide satisfactory results, double-bundle ACL reconstruction shows better functional results, with a faster return to sport activity, a lower re-operation rate and lower degenerative knee changes.

Even if pivot-shift (PS) test has been clinically used to specifically detect anterior cruciate ligament (ACL) injury, the main problem in using this combined test has been yet associated with the difficulty of clearly quantifying its outcome. The goal of this study was to describe an original non-invasive methodology used to quantify PS test, highlighting its possible clinical reliability. The method was validated on 66 consecutive unilateral ACL-injured patients. A commercial triaxial accelerometer was non-invasively mounted on patient's tibia, the corresponding 3D acceleration was acquired during PS test execution and a set of specific parameters were automatically identified on the signal to quantify the test. PS test was repeated three times on both injured and controlateral limbs. Reliability of the method was found to be good (mean intra-rater intraclass correlation coefficient was 0.79); moreover, we found that ACL-deficient knees presented statistically higher values for the identified parameters--than the controlateral healthy limbs, averagely reporting also large effect size.

Lachman, drawer, and pivot-shift (PS) tests are important in the assessment of ACL reconstruction. The goal of this work was to analyze the reliability of the PS test using a navigation system, identifying a set of new quantitative parameters and evaluating their clinical relevance. Eighteen patients that underwent anatomic double-bundle ACL reconstruction were included. The new dynamic parameters were: anteroposterior translation of the medial and lateral compartments and the joint center and internal/external and varus/valgus rotations of the joint. For each parameter we measured the peaks and the areas obtained during the test. Intratester repeatability, comparisons of pre-and postoperative laxities, and correlations between the PS peaks and the corresponding peaks obtained with standard static tests were evaluated. Areas, peaks, and static laxity outcomes were compared, grouping patients according to the preoperative International Knee Documentation Committee (IKDC) score. The PS test was reliable in identifying the surgical reconstruction. Correlation analysis showed good coefficients both for pre-and postoperative values. Patients with IKDC grade ''D'' had larger areas during the PS compared to patients with grade ''C''. Our analysis is helpful for characterizing patient-specific laxity and surgical performance, thus highlighting the clinical relevance of the PS test. ß

Case series.

We conclude that adductor tubercle can be used as a morphologic landmark to determine the knee joint line position, because a linear correlation between femoral width and distance from the adductor tubercle to the joint line was found.

A computer navigation system was used to collect kinematic data of 18 subjects undergoing ACL reconstruction. Surgical procedure was an anatomical four-tunnel hamstring double-bundle reconstruction. Static laxity and dynamic laxity were analyzed before and after graft passage and fixation. Correlations between static and dynamic laxities as well as with the preoperative IKDC score were determined. Static and dynamic laxities were significantly reduced after anatomic double-bundle ACL reconstruction (P < 0.05). There were no significant correlations between static and dynamic laxities (r < 0.4, P > 0.05). The preoperative IKDC score was only related to preoperative dynamic laxity (P < 0.01). The dynamic evaluation of pivot shift is able to better describe knee laxity, in particular rotational laxities and has no correlation with static laxity.

The MPFL has an aponeurotic nature. It works as a restraint during motion, with an active role under high stress on lateral side, but with a small contribution during neutral knee flexion. Its biomechanical behaviour under loading conditions should be kept into account when performing surgical reconstruction of this ligamentous structure.

Treating anterior cruciate ligament (ACL) lesions combined with a torn medial collateral ligament (MCL) is controversial because residual laxity may lead to stretching of the ACL graft and eventual failure of the reconstruction. Few studies describe the in vivo translations of combined ACL and MCL injuries. We compared the preoperative and postoperative laxity between patients with combined ACL+MCL Grade II injuries and isolated ACL ruptures and tested whether an ACL reconstruction could restore all laxities in both groups. We evaluated knee kinematics during ACL reconstruction in 57 patients (37 ACL lesions and 20 ACL+MCL injury). Laxity tests were performed before and after graft fixation. Postoperatively, there was greater anteroposterior laxity and greater varus-valgus laxity in the group with MCL injury compared to the group with an ACL lesion only. This finding suggests residual laxities remain when ACL reconstruction is performed in patients with combined ACL+MCL lesion, and raises the question of addressing the MCL ligament when Grade II laxity is found.