Increased Rotatory Laxity after Anterolateral Ligament Lesion in Anterior Cruciate Ligament- (ACL-) Deficient Knees: A Cadaveric Study with Noninvasive Inertial Sensors.

The anterolateral ligament (ALL) has been suggested as an important secondary knee restrain on the dynamic laxity in anterior cruciate ligament- (ACL-) deficient knees. Nevertheless, its kinematical contribution to the pivot-shift (PS) phenomenon has not been clearly and objectively defined, and noninvasive sensor technology could give a crucial contribution in this direction. The aim of the present study was to quantify in vitro the PS phenomenon in order to investigate the differences between an ACL-deficient knee and an ACL+ALL-deficient knee. Ten fresh-frozen paired human cadaveric knees (n = 20) were included in this controlled laboratory study. Intact, ACL-deficient, and ACL+ALL-deficient knees were subjected to a manual PS test quantified by a noninvasive triaxial accelerometer (KiRA, OrthoKey). Kinematic data (i.e., posterior acceleration of the tibial lateral compartment) were recorded and compared among the three statuses. Pairwise Student's t-test was used to compare the single groups (p < 0.05). Intact knees, ACL-deficient knees, and ACL+ALL-deficient knees showed an acceleration of 5.3 ± 2.1 m/s2, 6.3 ± 2.3 m/s2, and 7.8 ± 2.1 m/s2, respectively. Combined sectioning of ACL and ALL resulted in a statistically significant acceleration increase compared to both the intact state (p < 0.01) and the ACL-deficient state (p < 0.01). The acceleration increase determined by isolated ACL resection compared to the intact state was not statistically significant (p > 0.05). The ALL sectioning increased the rotatory laxity during the PS after ACL sectioning as measured through a user-friendly, noninvasive triaxial accelerometer.

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.

Validation of an optical, computer-assisted technique for intraoperative tracking of 3-dimensional canine stifle joint motion.

Background: Cranial cruciate ligament (CCL) rupture is the most common orthopedic pathology in dog and in men. In human, optical computer-assisted technique is considered as a repeatable and reliable method for the biomechanical assessment of joint kinematics and laxity in case of CCL surgery. Aim: To evaluate the repeatability and reliability afforded by clinical tests in terms of laxity measured by means of a computer-assisted tracking system in two canine CCL conditions: CCL-Intact, CCL-Deficient. Methods: Fourteen fresh frozen canine stifles were passively subjected to Internal/External (IE) rotation at 120° of flexion and Cranial drawer test (CC). To quantify the repeatability and the reliability, intra-class correlation coefficient (ICC) and the mean percent error were evaluated (Δ r %). Results: The study showed a very good intra-class correlation, before and after CCL resection for kinematics tests. It was found a minimum ICC = 0.73 during the IE rotation in CCL-Intact and a maximum value of ICC = 0.97 for the CC displacement in CC-Deficient. IE rotation with CCL-Intact is the condition with the greatest Δ r % = 14%, while the lowest Δ r % = 6% was obtained for CC displacement in CCL-Deficient. Conclusion: The presented work underlined the possibility of using a computer-assisted method also for biomechanical studies concerning stifle kinematics and laxity.

ACL reconstruction with lateral plasty reduces translational and rotatory laxity compared to anatomical single bundle and non-anatomical double bundle surgery: An in vivo kinematic evaluation with navigation system.

BACKGROUND: Significantly better stability may be achieved with a Single Bundle Lateral Plasty (SBLP) reconstruction compared with the Single Bundle (SB) and Double Bundle (DB) procedures. METHODS: The study included 42 patients who underwent ACL reconstruction. Patients were randomly selected for one of the following surgical procedure defining three study groups: Single-Bundle-Lateral-Plasty, Single-Bundle and Double-Bundle procedures. Laxity evaluation was performed with an intraoperative navigation system. Lachman test (AP30), Drawer test (AP90), Varus-Valgus stress test at 0° and 30° knee flexion (VV0, VV30), Internal-External rotation (IE30, IE90), and pivot shift (PS) test are the clinical test executed for the laxity evaluation. Laxity reduction was defined as the difference between laxity before the fixation of the graft used for the reconstruction and the laxity just after its fixation. FINDINGS: For all the analyzed surgical techniques, the pre-reconstruction laxity values were statistically higher (P < 0.05) than the post-reconstruction values for all the analyzed tests. The analysis of the Drawer test and Internal-External rotation at 30° and 90° of knee flexion, highlighted a significant difference at time zero after surgery among the three study groups. The results showed that the SBLP technique had the highest reduction values compared to SB (PIE90 = 0.001) and DB (PAP90 = 0.012; PIE30 = 0.021; PIE90 = 0.003) techniques. INTERPRETATION: SBLP technique showed significantly superior results in terms of antero-posterior and internal-external laxity reduction at time-zero after ACL reconstruction.

Patients With Failed Anterior Cruciate Ligament Reconstruction Have an Increased Posterior Lateral Tibial Plateau Slope: A Case-Controlled Study.

PURPOSE: To compare knee anatomical parameters of patients with failed anterior cruciate ligament reconstruction (ACL-R) with those of a control group of sex-matched patients with successful ACL-R. METHODS: Forty-three patients (34 male, 9 female) who experienced graft failure after ACL-R were enrolled in the failed group. These patients were matched to a control group of 43 patients who underwent primary ACL-R with a minimum follow-up of 24 months. On magnetic resonance imaging, the following parameters were evaluated: transepicondylar distance, lateral and medial femoral condyle widths, tibial plateau width, notch width index, and the ratio of width and height of the femoral notch, ratio between the height and depth of the lateral and medial femoral condyle, lateral and medial posterior tibial slopes, and anterior subluxation of the lateral and medial tibial plateau. Multivariate regression with backward elimination, including only the previously identified significant variables, defined the independent predictors for revision surgery. RESULTS: The anatomical variables that were significantly different between the 2 study groups were lateral and medial posterior tibial slopes, anterior subluxation of the lateral and medial tibial plateau, medial tibial plateau width, lateral tibial plateau width, medial femoral condyle width, and transepicondylar distance; however, the multivariate regression analysis identified the lateral posterior tibial slope (LTPs), the anterior subluxation of the medial tibial plateau, and the medial femoral condyle width as significant independent predictors (P < .05). The LPTs had the highest coefficient and the highest sensitivity (88%) and specificity (84%) to identify failures when considering the optimal cutoff value of 7.4°. CONCLUSIONS: Several anatomical parameters have been identified that differ significantly between patients with failed ACL-R and those without a documented failure. The most accurate predictor of ACL failure was an LTPs >7.4°, with a sensitivity of 88% and specificity of 84%. Surgeons should consider measuring LTPs during preoperative assessment of ACL-injured patients, and patients with values >7.4° should be considered at high risk of ACL-R failure. LEVEL OF EVIDENCE: Level III retrospective prognostic trial.

Triaxial accelerometer can quantify the Lachman test similarly to standard arthrometers.

PURPOSE: To assess the relationship between the KiRA triaxial accelerometer and the KT-1000 measurements in the intact, anterior cruciate ligament (ACL) deficient, and ACL reconstructed knee joint for the quantification of the Lachman test. Moreover, the intra- and inter-examiner repeatability of the KiRA device will be determined. It was hypothesized that the side-to-side difference of the anterior tibial translation as measured by the KiRA device would be equivalent to the one measured by the KT-1000 during the Lachman test. METHODS: Sixty patients were divided into three groups and have been prospectively included in the present study. Group_A composed of 20 patients with a diagnosis of an isolated ACL tear. Group_B composed of 20 patients who underwent ACL reconstruction with a Single-Bundle Lateral Plasty (SBLP) technique with at least 20 years of follow-up. Group_C was the control group and included 20 patients with no history of ACL lesion. Lachman test has been performed at manual-maximum load on both sides, the involved and the contralateral and analyzed with the two different devices. RESULTS: The KiRA device in terms of side-to-side difference resulted not statistically different from the measurement of the KT-1000 arthrometer for the three study groups (n.s): Group_A: (4 ± 2 mm KiRA, 4 ± 2 mm KT1000), Group_B: (4 ± 2 mm KiRA, 4 ± 2 mm KT-1000), Group_C: (4 ± 2 mm KiRA, 4 ± 2 mm KT-1000), an excellent intra- (ICC = 0.88-0.89) and inter-examiner (ICC = 0.79) agreement was found for KiRA measurements. CONCLUSION: The KiRA (I+, Italy) device offers a valid method to quantify the Lacham test. LEVEL OF EVIDENCE: II.

Anterior cruciate ligament reconstruction with an all-epiphyseal "over-the-top" technique is safe and shows low rate of failure in skeletally immature athletes.

PURPOSE: The aim of this study was to follow up, clinically and radiographically, skeletally immature patients who underwent ACL reconstruction with an all-epiphyseal "over-the-top" technique. METHODS: Twenty athletes aged between 8 and 13 years were enrolled and retrospectively evaluated. The subjects underwent surgical ACL reconstruction between 2009 and 2013. The surgical technique consisted of a single-bundle all-epiphyseal ACL reconstruction with an extra-articular lateral tenodesis. The mean follow-up was 54 months [34-123] after surgery. Clinically, the patients were evaluated pre- and post-operatively with Lysholm and KOOS scores; sport activity level was evaluated using the pre-injury, pre-operative and post-operative Tegner scores. Objective IKDC was calculated post-operatively. The joint laxity was evaluated by KT1000 and Rolimeter arthrometers. Panoramic AP standing radiographs of the lower limbs and lateral knee radiographs were also taken at the follow-up to evaluate limb length discrepancies (LLD) and axial malalignment. Normally distributed parameters were presented as mean ± standard deviation, while the non-normally distributed parameters were presented as median [25° percentile, 75° percentile]. RESULTS: Clinical scores showed significant (P < 0.01) improvement: Lysholm and KOOS scores improved from 40 [22; 65] and 59 [42, 73], respectively, to 100 [95; 100] and 99 [97;100] after surgery. Tegner score improved from 2 [2; 2] pre-operatively to 7 [3; 9] at follow-up (P < 0.01). At follow-up, IKDC score was A for 19 patients and one who scored B. All patients returned to sport activity and had good stability at follow-up: the KT1000 showed a median side-to-side difference of 0.0 mm [- 0.4; 1.0] for the standard force evaluation and 0.0 mm [- 1.0; 0.8] for manual-maximum test. The Rolimeter showed median side-to-site difference of 0.0 mm [- 1.0; 0.8]. Three minor leg length discrepancies and axial deviations were observed at the radiograph: one patient had 0.6 cm lengthening and 4° of varus, one had 1 cm lengthening, and one had 3° of varus (in comparison with the non-operated limb). No re-injury was observed. CONCLUSION: This study demonstrates that the modified all-epiphyseal single-bundle "over-the-top" technique is a viable and safe option for ACL reconstruction in pediatric subjects. These results support once more that not only ACL reconstruction is a safe procedure in skeletally immature patients, but also it is highly recommended for those who want to pursue an active and sportive life. LEVEL OF EVIDENCE: Case series, IV.

Anatomic Anterior Cruciate Ligament Reconstruction Using Hamstring Tendons Restores Quantitative Pivot Shift.

BACKGROUND: It is still uncertain how surgical reconstruction of the anterior cruciate ligament (ACL) is able to restore rotatory laxity of the involved joint. The desired amount of restraint applied by the ACL graft, as compared with the healthy knee, has not been fully clarified. PURPOSE: To quantify the ability of single-bundle anatomic ACL reconstruction using hamstring tendons in reducing the pivot-shift phenomenon immediately after surgery under anesthesia. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: An inertial sensor and image analysis were used at 4 international centers to measure tibial acceleration and lateral compartment translation of the knee, respectively. The standardized pivot-shift test was quantified in terms of the side-to-side difference in laxity both preoperatively and postoperatively with the patient under anesthesia. The reduction in both tibial acceleration and lateral compartment translation after surgery and the side-to-side difference were evaluated using the Wilcoxon signed-rank test. Alpha was set at P < .05. RESULTS: A total of 107 patients were recruited for the study, and data were available for 89 patients. There was a statistically significant reduction in quantitative rotatory knee laxity between preoperatively (inertial sensor, 2.55 ± 4.00 m/s2; image analysis, 2.04 ± 2.02 mm) and postoperatively (inertial sensor, -0.54 ± 1.25 m/s2; image analysis, -0.10 ± 1.04 mm) between the involved and healthy joints, as measured by the 2 devices (P < .001 for both). Postoperatively, both devices detected a lower rotatory laxity value in the involved joint compared with the healthy joint (inertial sensor, 2.45 ± 0.89 vs 2.99 ± 1.10 m/s2, respectively [P < .001]; image analysis, 0.99 ± 0.83 vs 1.09 ± 0.92 mm, respectively [P = .38]). CONCLUSION: The data from this study indicated a significant reduction in the pivot shift when compared side to side. Both the inertial sensor and image analysis used for the quantitative assessment of the pivot-shift test could successfully detect restoration of the pivot shift after anatomic single-bundle ACL reconstruction. Future research will examine how pivot-shift control is maintained over time and correlation of the pivot shift with return to full activity in patients with an ACL injury.

Anatomical features of tibia and femur: Influence on laxity in the anterior cruciate ligament deficient knee.

BACKGROUND: Until now, there has been a lack of in vivo analysis of the correlation between bony morphological features and laxity values after an anterior cruciate ligament (ACL) injury. METHODS: Forty-two patients who underwent ACL-reconstruction were enrolled. Static laxity was evaluated as: antero-posterior displacement and internal-external rotation at 30° and 90° of flexion (AP30, AP90, IE30, IE90) and varus-valgus rotation at 0° and 30° of flexion (VV0, VV30). The pivot-shift (PS) test defined the dynamic laxity. Using magnetic resonance imaging, we evaluated the transepicondylar distance (TE), the width of the lateral and medial femoral condyles (LFCw and MFCw) and tibial plateau (LTPw and MTPw), the notch width index (NWI) and the ratio of width and height of the femoral notch (N-ratio), the ratio between the height and depth of the lateral and medial femoral condyle (LFC-ratio and MFC-ratio), the lateral and medial posterior tibial slopes (LTPs and MTPs) and the anterior subluxation of the lateral and medial tibial plateau with respect to the femoral condyle (LTPsublx and MTPsublx). RESULTS: Concerning the AP30, LTPs (P=0.047) and MTPsublx (P=0.039) were shown to be independent predictors while for the AP90 only LTPs (P=0.049) was an independent predictor. The LTPs (P=0.039) was shown to be an independent predictor for IE90 laxity, while for the VV0 test it was identified as the LFCw (P=0.007). CONCLUSIONS: A higher antero-posterior laxity at 30° and 90° of flexion was found in those with a lateral tibial slope <5.5°.

The Anterolateral Ligament Does Exist: An Anatomic Description.

The debate around the existence, anatomy, and role of the so-called anterolateral ligament of the knee represents one of the main sources of recent controversy among orthopedic surgeons. In the modern era of sports medicine, several content experts have contributed to the understanding of the anatomy of the anterolateral aspect of the knee. This article analyzes the historical, phylogenetic, anatomic, arthroscopic, and radiological evidence regarding the anterolateral ligament. The existence of the anterolateral ligament as a distinct ligamentous structure and its exact anatomic features are still matters of controversy and ongoing study.

Over-the-top ACL Reconstruction Plus Extra-articular Lateral Tenodesis With Hamstring Tendon Grafts: Prospective Evaluation With 20-Year Minimum Follow-up.

BACKGROUND: There are few published studies with very long-term follow-up of combined intra- and extra-articular anterior cruciate ligament (ACL) reconstruction. PURPOSE: To analyze clinical and radiographic outcomes of over-the-top ACL reconstruction plus extra-articular lateral tenodesis with autologous hamstrings at minimum 20-year follow-up. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Of 60 originally eligible patients who underwent over-the-top ACL reconstruction with double-stranded hamstring tendon (leaving intact graft tibial insertions) and extra-articular lateral plasty (performed with the remnant part of tendons), 52 were prospectively evaluated at a minimum 20-year follow-up (mean follow-up, 24 years; 41 men, 11 women; mean age at time of surgery, 25.5 ± 7.6 years). Twenty-nine patients were available for prospective evaluations: clinical (Lysholm, Tegner, and objective International Knee Documentation Committee [IKDC]), instrumented (KT-2000), and radiographic (standard, long-standing, and Merchant views). Subjective KOOS (Knee injury and Osteoarthritis Outcome Score) and objective inertial sensor pivot-shift analysis (KiRA) were carried out at final follow-up. Twenty-three patients were investigated by phone interview for subjective Tegner score and documented complications, rerupture, or revision surgery. RESULTS: At final follow-up, mean Lysholm score was 85.7 ± 14.6; median Tegner score, 4 (range, 3-5); sport activity resumption, 86.2%; and objective IKDC score, good or excellent in 86% of patients (31%, A; 55%, B). Only 3 of 26 patients (12%) had >5-mm manual maximum KT-2000 side-to-side difference. KiRA system documented positive pivot-shift (>0.9-m/s2 tibial acceleration side-to-side difference) in these 3 of 26 patients (12%). Statistically significant changes were as follows: decrease in Tegner score from 7 (range, 6-8) at 5-year follow-up to 4 (range, 3-5) at 10 years ( P < .0001) and decrease in Lysholm score from 96.1 ± 7.3 at 10-year follow-up to 85.7 ± 14.6 at 20 years ( P = .0003). Radiographic evaluation demonstrated significant difference of medial joint space between injured and healthy knees in patients with concomitant medial meniscectomy (n = 8, 3.2 ± 0.6 vs 5.0 ± 1.8 mm, P = .0114). No significant differences were reported regarding lateral or patellofemoral joint space. One patient (2%) experienced rerupture, with 3 of 52 (5.8%) having a contralateral ACL injury (excluded from KT-2000 and radiographic evaluations). Overall, 4 of 29 clinical failures (objective IKDC, KT-2000) and 1 rerupture among 52 patients were registered at final follow-up. CONCLUSION: Studied surgical technique demonstrated good results in laxity control at 20-year minimum follow-up. The lateral extra-articular plasty associated with ACL reconstruction did not generate lateral knee or patellofemoral osteoarthritis. The factor increasing osteoarthritis was meniscectomy.

The patellofemoral joint: from dysplasia to dislocation.

Patellofemoral dysplasia is a major predisposing factor for instability of the patellofemoral joint. However, there is no consensus as to whether patellofemoral dysplasia is genetic in origin, caused by imbalanced forces producing maltracking and remodelling of the trochlea during infancy and growth, or due to other unknown and unexplored factors.The biomechanical effects of patellofemoral dysplasia on patellar stability and on surgical procedures have not been fully investigated. Also, different anatomical and demographic risk factors have been suggested, in an attempt to identify the recurrent dislocators. Therefore, a comprehensive evaluation of all the radiographic, MRI and CT parameters can help the clinician to assess patients with primary and recurrent patellar dislocation and guide management.Patellofemoral dysplasia still represents an extremely challenging condition to manage. Its controversial aetiology and its complex biomechanical behaviour continue to pose more questions than answers to the research community, which reflects the lack of universally accepted guidelines for the correct treatment. However, due to the complexity of this condition, an extremely personalised approach should be reserved for each patient, in considering and addressing the anatomical abnormalities responsible for the symptoms. Cite this article: EFORT Open Rev 2017;2. DOI: 10.1302/2058-5241.2.160081. Originally published online at www.efortopenreviews.org.

Mechanisms and situations of anterior cruciate ligament injuries in professional male soccer players: a YouTube-based video analysis.

BACKGROUND: Soccer is considered the most popular sport in the world concerning both audience and athlete participation, and the incidence of ACL injury in this sport is high. The understanding of injury situations and mechanisms could be useful as substratum for preventive actions. PURPOSE: To conduct a video analysis evaluating the situations and mechanisms of ACL injury in a homogeneous population of professional male soccer players, through a search entirely performed on the YouTube.com Web site focusing on the most recent years. METHODS: A video analysis was conducted obtaining videos of ACL injury in professional male soccer players from the Web site YouTube. Details regarding injured players, events and situations were obtained. The mechanism of injury was defined on the basis of the action, duel type, contact or non-contact injury, and on the hip, knee and foot position. RESULTS: Thirty-four videos were analyzed, mostly from the 2014-2015 season. Injuries occurred mostly in the first 9 min of the match (26%), in the penalty area (32%) or near the side-lines (44%), and in non-rainy conditions (97%). Non-contact injuries occurred in 44% of cases, while indirect injuries occurred in 65%, mostly during pressing, dribbling or tackling. The most recurrent mechanism was with an abducted and flexed hip, with knee at first degrees of flexion and under valgus stress. CONCLUSIONS: Through a YouTube-based video analysis, it was possible to delineate recurrent temporal, spatial and mechanical characteristics of ACL injury in male professional soccer players. LEVEL OF EVIDENCE: Level IV, case series.

Analysis of the influence of anaesthesia on the clinical and quantitative assessment of the pivot shift: a multicenter international study.

PURPOSE: The main goal of this work was to evaluate the pivot shift test in awake and anesthetized patients by using two different quantitative methodologies and comparing the results with the standard clinical grading, taking advantage of a multicenter international study. METHODS: Patients between 16 and 50 years of age undergoing primary unilateral single-bundle anterior cruciate ligament (ACL) reconstruction were considered eligible. The pivot shift test was performed pre-operatively, with the patient awake and again with the patient under general anaesthesia. The pivot shift test was clinically graded as defined by the International Knee Documentation Committee. The instrumented assessment was performed by using two non-invasive acquisition systems; specifically, a system exploiting an inertial sensor and a video-based application developed on a commercial tablet using skin markers. Lateral compartment translation and the tibial acceleration reached during joint reduction were used as quantitative parameters. RESULTS: A total of 103 patients were enrolled in the study. Statistically significant difference was found between the distributions of clinical grade evaluated in awake patients and those under general anaesthesia (P < 0.01). Comparing awake patients to those under general anaesthesia, lower values were found both for tibial acceleration (3.7 ± 1.5 vs 6.0 ± 4.6 m/s2, P < 0.01) and lateral compartment translation of the involved limb (2.2 ± 1.7 vs 3.0 ± 2.2 mm, P < 0.01). CONCLUSIONS: This study indicated that significant differences in the grading of the pivot shift test exist between awake and anesthetized patients, regardless of the use of quantitative instruments during the evaluation. Actual clinical assessment reported indeed its weakness, presenting subjective variability and dependence on tester's experience. However, several factors might influence the validity of awake examination such as experience level of examiner and cultural factors, as seen in this international multicenter study. LEVEL OF EVIDENCE: Prospective comparative study, Level II.

Magnetic resonance imaging after anterior cruciate ligament reconstruction: A practical guide.

Anterior cruciate ligament (ACL) reconstruction is one of the most common orthopedic procedures performed worldwide. In this regard, magnetic resonance imaging (MRI) represents a useful pre-operative tool to confirm a disruption of the ACL and to assess for potential associated injuries. However, MRI is also valuable post-operatively, as it is able to identify, in a non-invasive way, a number of aspects and situations that could suggest potential problems to clinicians. Graft signal and integrity, correct tunnel placement, tunnel widening, and problems with fixation devices or the donor site could all compromise the surgical outcomes and potentially predict the failure of the ACL reconstruction. Furthermore, several anatomical features of the knee could be associated to worst outcomes or higher risk of failure. This review provides a practical guide for the clinician to evaluate the post-surgical ACL through MRI, and to analyze all the parameters and features directly or indirectly related to ACL reconstruction, in order to assess for normal or pathologic conditions.

Evaluation of RSA set-up from a clinical biplane fluoroscopy system for 3D joint kinematic analysis.

PURPOSE: dinamic roentgen stereophotogrammetric analysis (RSA), a technique currently based only on customized radiographic equipment, has been shown to be a very accurate method for detecting three-dimensional (3D) joint motion. The aim of the present work was to evaluate the applicability of an innovative RSA set-up for in vivo knee kinematic analysis, using a biplane fluoroscopic image system. To this end, the Authors describe the set-up as well as a possible protocol for clinical knee joint evaluation. The accuracy of the kinematic measurements is assessed. METHODS: the Authors evaluated the accuracy of 3D kinematic analysis of the knee in a new RSA set-up, based on a commercial biplane fluoroscopy system integrated into the clinical environment. The study was organized in three main phases: an in vitro test under static conditions, an in vitro test under dynamic conditions reproducing a flexion-extension range of motion (ROM), and an in vivo analysis of the flexion-extension ROM. For each test, the following were calculated, as an indication of the tracking accuracy: mean, minimum, maximum values and standard deviation of the error of rigid body fitting. RESULTS: in terms of rigid body fitting, in vivo test errors were found to be 0.10±0.05 mm. Phantom tests in static and kinematic conditions showed precision levels, for translations and rotations, of below 0.1 mm/0.2° and below 0.5 mm/0.3° respectively for all directions. CONCLUSIONS: the results of this study suggest that kinematic RSA can be successfully performed using a standard clinical biplane fluoroscopy system for the acquisition of slow movements of the lower limb. CLINICAL RELEVANCE: a kinematic RSA set-up using a clinical biplane fluoroscopy system is potentially applicable and provides a useful method for obtaining better characterization of joint biomechanics.

Soft tissues contribution to hip joint kinematics and biomechanics.

PURPOSE: To quantitatively describe the kinematic behaviour of the hip joint with particular interest in the contribution of the periarticular soft tissues to the stability. To quantitatively assess the sealing function of the acetabular labrum of an intact labrum, the effect of a labral-chondral separation and different surgical approaches. The biomechanics of the joint during specific clinical examinations was also assessed. METHODS: All the kinematics tests, manually performed, have been acquired using a navigation systems. For the first part of the study, 4 hemi-corpse specimens were evaluated with the hip in 36 different positions with all the soft tissues intact, after removal of skin and muscles and after partial capsulectomy. During the second and the third part of the analysis 8 fresh frozen hips were analysed. They were tested during 3 different positions used for femeroacetabular impingement (FAI) diagnosis, during pivoting motion and distraction test. Contact area between acetabulum and femoral head, range of movement (RoM) and hip joint centre (HJC) displacement were evaluated. RESULTS: Femoral head displacement occured in all 3 directions and increased as more tissue was removed. Considering both pivoting motion and distraction test there was an increase of the HJC displacement after labral tear. Analogously, the tested surgical approaches showed different results compared to intact condition. Our analysis confirmed that the hip position with Hyperextension-External Rotation is specific for the analysis of the posteriorsuperior region of the acetabulum. CONCLUSIONS: The study showed that hip joint does not act as a true ball-and-socket joint and the femoral head anatomical displacement is strongly affected by the removal of periarticular soft tissues, labral repair as well as labrectomy.

Assessment of the pivot shift using inertial sensors.

The pivot shift test is an important clinical tool used to assess the stability of the knee following an injury to the anterior cruciate ligament (ACL). Previous studies have shown that significant variability exists in the performance and interpretation of this manoeuvre. Accordingly, a variety of techniques aimed at standardizing and quantifying the pivot shift test have been developed. In recent years, inertial sensors have been used to measure the kinematics of the pivot shift. The goal of this study is to present a review of the literature and discuss the principles of inertial sensors and their use in quantifying the pivot shift test.

Is Sport Activity Possible After Arthroscopic Meniscal Allograft Transplantation? Midterm Results in Active Patients.

BACKGROUND: Meniscal allograft transplantation (MAT) has produced good to excellent results in the general population; however, few investigations have examined MAT in athletes and sport-related outcomes. PURPOSE: To report midterm clinical outcomes of MAT and the rate of return to sport in a physically active population. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The study included all physically active patients who underwent arthroscopic MAT without bone plugs and had a minimum of 2 years of follow-up at a single institution. Clinical evaluation was performed with the Knee injury and Osteoarthritis Outcome Score (KOOS), the Tegner activity scale, and a 0- to 100-point subjective scale for knee function and satisfaction. Outcomes evaluated included ability to return to sport, time to return to sport, level of sport activity upon return compared with preinjury level, and level of decrease in sport participation or reasons for not returning to sport participation. Comparisons were made between patients who did or did not return to sport and between patients who returned to the same level or a decreased level. Regression analysis was performed to determine the variables affecting the outcomes. RESULTS: Eighty-nine patients, whose mean ± SD age at surgery was 38.5 ± 11.2 years, were evaluated to a mean follow-up of 4.2 ± 1.9 years. Total KOOS improved from a mean ± SD of 39.5 ± 18.5 preoperatively to 84.7 ± 14.8 at the latest follow-up (P < .001). The Tegner score improved significantly from a median of 2 (interquartile range [IQR], 1-4) preoperatively to a median of 4 (IQR, 3-6) at the latest follow-up (P < .001), although it did not reach the preinjury level of 6 (IQR, 5-7) (P < .001). Older age at surgery was correlated with the worst clinical results. Sixty-six patients (74%) were able to return to sport after 8.6 ± 4.1 months. Forty-four (49%) returned to the same level as preinjury. Patients who did not return to sport activity and those who reduced their activity level at follow-up had inferior subjective outcomes compared with those who returned to sport and those who returned to their preinjury levels, respectively. Only 11 patients (12%) underwent a surgical procedure during the follow-up period. CONCLUSION: Arthroscopic MAT without bone plugs improved knee function and reduced pain, allowing sport resumption in 74% of patients and return to the preinjury activity level in 49% of patients at midterm follow-up. Of all the demographic and surgical variables, only age at surgery seemed to affect outcomes.

Is PLC repair of a peel-off femoral lesion an effective option in a multiligament setting?

PURPOSE: Treatment of posterolateral corner (PLC) injury in the multiligament-injured knee is still controversial. The aim of this study was to investigate the clinical outcome of acute or sub-acute surgical repair of Type 1 and 2 PLC peel-off lesions in a multiligament setting. METHODS: Mini-open direct repair of the PLC was performed in 13 patients. Combined PCL, ACL and MCL injuries were simultaneously managed. Telos valgus and varus stress radiographs at 30° of flexion with 150 N load were used to investigate medial and lateral joint opening. Posterior stress radiograph with 150 N load was used to investigate the function of the PCL. External rotational laxity was assessed with a dial test at 30° of knee flexion, and photographs were taken to measure angles. Anterior displacement was examined using the manual maximum test performed with a KT-1000 arthrometer. RESULTS: A statistically significant reduction between pre- and postoperative laxity values was achieved for every test. Particularly, lateral joint opening side-to-side difference reduced from 10.3 ± 4.0 to 1.0 ± 3.2 mm and external rotation reduced from 15 ± 8° to 0° ± 6° more than that of the contralateral uninjured knee. The medial joint opening side-to-side difference reduced from 11.5 ± 5.6 to 2.6 ± 2.7 mm in the 7 patients surgically managed for MCL lesion. The anterior tibial displacement side-to-side difference reduced from 14.0 ± 5.0 to 3.0 ± 5.0 mm in the 9 patients surgically managed for ACL lesion. The posterior tibial translation side-to-side difference reduced from 11.1 ± 5.1 to 4.4 ± 3.9 mm in the 11 patients treated for PCL lesion. CONCLUSION: The main finding of the current study is that acute repair of Type 1 and 2 PLC peel-off injury proved to be an effective procedure to restore PLC function in a multiligament-injured knee. These data enabled the current literature with an effective treatment option to face such a complex and various scenarios such as multiligament-injured knee. LEVEL OF EVIDENCE: IV.