Anterolateral ligament of the knee: a step-by-step dissection.

BACKGROUND: The number of studies and clinical interest in the anterolateral ligament of the knee (ALL) has grown in recent years. A meticulous and accurate ALL dissection is vital in anatomic and biomechanical studies, and a standardized technique is not yet established. As such, the aim of this study was to describe a step-by-step ALL dissection technique that could help authors consistently identify the ALL. METHODS: Twenty knees from frozen adult cadavers, with no preference for sex or age, were included in the study. All the cadavers were dissected using the same technique to determine the incidence of the ALL. RESULTS: A transverse incision is performed in the iliotibial band (ITB), around 10 cm proximal to the topography of the lateral epicondyle of the femur. Next, the ITB undergoes anterograde blunt dissection until its insertion at Gerdy's tubercle in the tibia. Maintaining biceps femoris insertion, a dissection is performed anteriorly to it, until the lateral collateral ligament (LCL) is found. Using the LCL, internal rotation and 30 to 60° flexion as references, the ALL can be located in the anterolateral topography of the knee, with its origin near the lateral epicondyle (proximal and posterior) and insertion between Gerdy's tubercle and the fibula (4.0 mm to 7.0 mm below the tibial plateau), expanding to the lateral meniscus (between the body and anterior horn), exhibiting a mean length of 4.0 ± 0.4 cm and mean width of 5.5 ± 0.8 mm. CONCLUSIONS: The present article describes an effective and reproducible ALL dissection technique that made it was possible to identify the ligament in 100% of the cases in the present study.

The Effect of Sequential Tearing of the Anterior Cruciate and Anterolateral Ligament on Anterior Translation and the Pivot-Shift Phenomenon: A Cadaveric Study Using Navigation.

PURPOSE: To evaluate the effect of progressive lesions of the anterior cruciate ligament (ACL) and anterolateral ligament (ALL) on anterior tibial translation (ATT) as evaluated through the Lachman test and internal tibial rotation (ITR) during a dynamic pivot-shift test in a cadaveric model. METHODS: A total of 7 specimens were tested using a navigation system (2.2 OrthoPilot ACL navigation system). The anterior stability of the knee was measured through the Lachman test and dynamic rotational stability was measured through the pivot-shift test in 3 different conditions: intact knee; ACL-deficient knee; and finally, ACL- and ALL-deficient knee. The resulting measurements from the navigation system recorded the real-time changes in both translation and internal rotation during the Lachman and pivot-shift maneuvers. RESULTS: Mean ATT was 7.57 ± 0.53 mm in the intact knee, 14 ± 2.44 mm in the ACL-deficient knee, and 14 ± 2.44 mm in the ACL- and ALL-deficient knee. Mean ITR during the pivot-shift test was 10.14° ± 2.26° in the intact knee, 12.14° ± 2.19° in the ACL-deficient knee, and 18.86° ± 2.73° in the ACL- and ALL-deficient knee. There was a statistically significant difference in static ATT between the intact and ACL-deficient knees (P = .039) but no difference through the addition of an ALL lesion (P = .068). For dynamic rotational control testing, there was no significant difference in ATT between groups but a significant difference in ITR was found (F = 25.17, P = .00034). CONCLUSIONS: During the pivot-shift test, a combined lesion of the ACL and ALL has a significant effect on ITR whereas an isolated lesion of the ACL has no effect on either ATT or ITR. During the Lachman test, an isolated lesion of the ACL has a significant effect on ATT but an additional lesion of the ALL does not affect ATT. CLINICAL RELEVANCE: Dynamic rotational control as tested by the pivot-shift test is greatly influenced by a combined lesion of the ACL and ALL. In clinical cases of a pivot shift, addressing the anterolateral structures may be considered.

Anterolateral Ligament Expert Group consensus paper on the management of internal rotation and instability of the anterior cruciate ligament - deficient knee.

Purpose of this paper is to provide an overview of the latest research on the anterolateral ligament (ALL) and present the consensus of the ALL Expert Group on the anatomy, radiographic landmarks, biomechanics, clinical and radiographic diagnosis, lesion classification, surgical technique and clinical outcomes. A consensus on controversial subjects surrounding the ALL and anterolateral knee instability has been established based on the opinion of experts, the latest publications on the subject and an exchange of experiences during the ALL Experts Meeting (November 2015, Lyon, France). The ALL is found deep to the iliotibial band. The femoral origin is just posterior and proximal to the lateral epicondyle; the tibial attachment is 21.6 mm posterior to Gerdy's tubercle and 4-10 mm below the tibial joint line. On a lateral radiographic view the femoral origin is located in the postero-inferior quadrant and the tibial attachment is close to the centre of the proximal tibial plateau. Favourable isometry of an ALL reconstruction is seen when the femoral position is proximal and posterior to the lateral epicondyle, with the ALL being tight upon extension and lax upon flexion. The ALL can be visualised on ultrasound, or on T2-weighted coronal MRI scans with proton density fat-suppressed evaluation. The ALL injury is associated with a Segond fracture, and often occurs in conjunction with acute anterior cruciate ligament (ACL) injury. Recognition and repair of the ALL lesions should be considered to improve the control of rotational stability provided by ACL reconstruction. For high-risk patients, a combined ACL and ALL reconstruction improves rotational control and reduces the rate of re-rupture, without increased postoperative complication rates compared to ACL-only reconstruction. In conclusion this paper provides a contemporary consensus on all studied features of the ALL. The findings warrant future research in order to further test these early observations, with the ultimate goal of improving the long-term outcomes of ACL-injured patients. Level of evidence Level V-Expert opinion.

Isometric Characteristics of the Anterolateral Ligament of the Knee: A Cadaveric Navigation Study.

PURPOSE: To measure the variations in length during flexion and internal tibial rotation of the 3 different femoral insertions of the anterolateral ligament (ALL) while maintaining a fixed tibia insertion. METHODS: Twelve fresh-frozen cadaver knees were analyzed using a navigation system. Maximal distance variations of the 3 different anatomic femoral insertions of the ALL were measured during knee flexion and internal tibial rotation at 20° (IR20°) and 90° (IR90°). The 3 different femoral attachments were, as published, at the center of the lateral epicondyle, distal and anterior from this position, and proximal and posterior. Each of these 3 femoral insertions was coupled to the same tibial insertion at the tibial margin, halfway between the tip of the fibular head and the prominence of the Gerdy tubercle. RESULTS: During IR20°, variation in the distance between paired points is not different between the proximal-posterior, epicondyle, and distal-anterior femoral insertions. These variations were statistically different during IR90° for the 3 different femoral locations. In increasing degrees of flexion, there was a length decrease between paired points observed with the proximal-posterior position. A length increase was observed for both the epicondyle location and the distal-anterior location. CONCLUSIONS: The ALL did not reveal an isometric behavior at any of the femoral insertion locations but had different length change patterns during knee flexion and internal tibial rotation at 90°. The proximal and posterior to epicondyle femoral position is the only position with a favorable isometry, as shown by being tight in extension and in internal rotation at 20° and then relaxed when the knee goes to flexion at 120° and during internal rotation at 90°. CLINICAL RELEVANCE: Clinical relevance is significant with respect to optimizing the femoral position of an ALL reconstruction.

Femoral Origin of the Anterolateral Ligament: An Anatomic Analysis.

PURPOSE: To determine the location and variability of the anterolateral ligament (ALL) femoral origin. METHODS: The ALL was dissected and examined in 52 embalmed specimens, and the femoral origin was isolated. The presence of a bony or soft-tissue attachment, the relation to the lateral collateral ligament, the average diameter of the proximal origin, and the specific location of the origin relative to the lateral femoral epicondyle were recorded. RESULTS: The ALL was present in all 52 specimens, with a mean diameter of 11.85 mm, and was consistently attached to bone in all specimens. The ALL consistently overlapped the lateral collateral ligament near its attachment, with the location of the origin directly on the lateral epicondyle in 12 specimens (23%), with a shared lateral femoral condyle and with the origin slightly posterior and proximal to the lateral epicondyle in 30 specimens (58%), and with the origin completely posterior and proximal to the lateral epicondyle in 10 specimens (19%). CONCLUSIONS: The ALL showed a consistent bony origin overlapping the lateral collateral ligament in all specimens, with some variability in the femoral attachment, ranging from directly on the lateral epicondyle to posterior to the lateral epicondyle. CLINICAL RELEVANCE: The identification and description of the femoral origin of the ALL are crucial in understanding its role in the stability of the knee, as well as determining the appropriate position for the femoral origin placement in ALL reconstruction.

Comparison of glenoid inclination angle using different clinical imaging modalities.

BACKGROUND: The ß-angle, formed by the intersection of a line on the floor of the supraspinatus fossa and glenoid fossa line, has been described as a reliable measurement tool in the clinical setting to analyze glenoid inclination on the anteroposterior (AP) view of the shoulder. The purpose of this study was to compare the accuracy of the ß-angle measurement using different imaging modalities with a validated 3-dimensional (3D) software tool. MATERIALS AND METHODS: The ß-angle was measured on AP radiographs, unformatted 2-dimensional (2D) computed tomography (CT) scan, and reformatted 2D CT scan in the scapular plane for 51 shoulders of 49 patients undergoing primary total shoulder arthroplasty. Comparison to the glenoid inclination angle calculated by the 3D software was performed. RESULTS: The ß-angle measured on reformatted CT scan was found to be the most accurate measurement method, with a mean difference of 1° (standard deviation [SD], 0.5°) with respect to 3D measurement. On AP radiographs, the ß-angle was not as accurate, with a mean difference of 3° (SD, 0.7°; P < .006). The ß-angle on unformatted 2D CT scan was not a reliable method to measure glenoid inclination, with a mean difference of 10° (SD, 0.9°; P < .0001). CONCLUSION: The ß-angle measured with 2D CT scan formatted in the scapular plane was the most accurate method for measuring glenoid inclination. The ß-angle on the AP radiograph is less accurate and reliable. Measurement of the ß-angle on an unformatted 2D CT scan is not an acceptable method to determine glenoid inclination.

Correlation between glenoid inclination and critical shoulder angle: a radiographic and computed tomography study.

BACKGROUND: Increased critical shoulder angles consist of both the acromial cover and glenoid inclination and have been found in patients with rotator cuff pathology. The purpose of this study was to determine the correlation of the critical shoulder angle and glenoid inclination and to determine the difference in glenoid inclination between patients with osteoarthritis and massive rotator cuff tears. METHODS: The critical shoulder angle and glenoid inclination were measured on anteroposterior radiographs, and glenoid inclination was also measured on a validated 3-dimensional computer software program of 50 shoulders undergoing primary total shoulder arthroplasty. Twenty-five shoulders had osteoarthritis and A1 glenoids, as defined by the Walch classification, and were undergoing anatomic shoulder arthroplasty. The other 25 shoulders had massive rotator cuff tears and E0 glenoids, as defined by the Favard classification. The 2 groups were compared. RESULTS: Critical shoulder angle and glenoid inclination were significantly correlated (R(2) = 0.7426, P < .001). Shoulders with massive rotator cuff tears (E0) demonstrated increased glenoid inclination measurements than shoulders with osteoarthritis (A1). As measured by the 3-dimensional software, the massive rotator cuff group had a glenoid inclination of 13.6° ± 4.3° and the osteoarthritis group had a glenoid inclination of 4.7° ± 5.6°. When measured by anteroposterior radiographs, the average glenoid inclination was 13.6° ± 4.6° in the massive rotator cuff group and was 7.6° ± 5.01° in the osteoarthritic group . CONCLUSION: Glenoid inclination is linearly correlated with the critical shoulder angle and is significantly increased in patients with massive rotator cuff tears.

Evaluation of lengthening in reverse shoulder arthroplasty comparing X-rays and computerised tomography.

PURPOSE: The correct amount of arm lengthening in reverse shoulder arthroplasty is crucial to provide joint stability and good results. Determination has been proposed according to radiographs. However, radiographic measurements are error prone in regards to positioning of the arm with regard to the radiographic beam. The purpose of this study was to evaluate the precision of radiographic measurements compared to CT scans of the upper limb following reverse shoulder arthroplasty. METHODS: Thirty patients undergoing onlay reverse shoulder arthroplasty with comparative radiographs and CT scans of both humeri were included in this study. Arm length, humeral length as well as the arm and humeral lengthening were evaluated on pre- and postoperative radiographs compared to postoperative CT scans following a previously validated protocol. RESULTS: We found an excellent correlation for arm length and humeral length for radiographic and CT measurements (r > 0.90). The postoperative humeral and arm lengthening compared to the contralateral side was 0.1 (-1.2 to 1.2) cm and 2.8 (0.2 to 5.2) cm for the CT scans, and -0.6 (-4.1 to 2.0) cm and 1.9 (-2.3 to 5.0) cm for the radiographs. For arm lengthening, correlation coefficient was good (r = 0.7) even though radiographs indicated arm shortening in five cases whereas arm lengthening was observed on CT scans. CONCLUSIONS: Measurements on radiographs and CT scans are comparable in most of the cases. However, we observed some important variations that question the reliability of radiographic measurements in up to 20 % of cases. Therefore, a CT scan appears to be necessary in the event of postoperative complications (e.g., instability, neurological problems).

Active range of motion of the shoulder: a cross-sectional study of 6635 subjects.

Background: Normative data for passive range of motion are well established, but daily living is comprised of active motion. The purpose of this study was to establish normative values for active range of motion of the shoulder across age, sex, and arm. Our hypotheses were that active range of motion of the shoulder (1) decreases with age group, (2) differs between males and females, and (3) differs between the right arm and left arm. Methods: Shoulder active range of motion was captured with an eight-camera markerless motion capture system. Data were collected for a heterogenous sample of 6635 males and females of all ages. For each subject, 6 shoulder motions were collected with maximum values measured: external rotation, internal rotation, flexion, extension, abduction, and horizontal abduction. Three-way repeated measures analyses were performed, with 2 between-subject factors (age group and sex) and 1 within-subject factor (arm). The unadjusted threshold for statistical significance was α = 0.05. Results: External rotation decreased with age (approximately 10° decrease from below 30 years to above 60 years). External rotation was approximately 5° greater in the right arm, whereas internal rotation was approximately 5° greater in the left arm. Flexion decreased with age (approximately 15° decrease from below 20 years to above 60 years). For age groups from 10 to 59 years, extension and horizontal abduction were approximately 5° to 10° greater in females than males. Abduction was greater for females than males. Abduction was also greater in younger people (aged 10-29 years) than older people. Conclusion: In general, active range of motion of the shoulder decreases with age. Sex (male/female) and arm side (right/left) also influence shoulder range of motion.

Medial Patellofemoral Ligament Reconstruction Using Gracilis Tendon Graft and "All Suture" Knotless Anchors for Patellar Fixation.

Patellar dislocation is a frequent sports-related knee injury. The primary restraint to lateral translation of patella is medial patellofemoral ligament. Several treatments for patella dislocation have been described in the literature. The purpose of this Technical Note is to describe the surgical technique for medial patellofemoral ligament reconstruction using gracilis tendon and 2 knotless soft anchors, avoiding patella tunneling.

Evidence-Based Data Models for Return-to-Play Criteria after Anterior Cruciate Ligament Reconstruction.

The anterior cruciate ligament (ACL) tear is one of the most common knee injuries in sports that require side-to-side pivoting movements. While the timeline and specific goals during rehabilitation protocols may vary, ACL reconstruction (ACLR) is the preferred procedure necessary to return these athletes to their respective field of play. However, there are no validated guidelines that define a specific timepoint when it is safe for an athlete to return-to-play, as functional movement deficit may be present much longer than six months post ACLR. A retrospective cross-sectional analysis was conducted on 33 subjects that underwent ACLR. As a part of standard of care, each subject completed a movement screening protocol at a singular timepoint during their rehabilitation process. An innovative three-dimensional markerless motion capture system was used to obtain three algorithm-derived biometric variables: mobility, alignment, and readiness. Significant gradual improvements in mobility and readiness were observed throughout a 3-6-month post ACLR procedure period. When examining the data trends, it was obvious that not all patients responded identically to treatment plans provided by clinical professionals. Therefore, the findings of the present study suggest that the decision regarding when it is safe to return to play needs to be determined on an individual basis.

No difference in clinical and radiological outcomes following fixation of transverse patella fractures with either suture tape or metallic cerclage: A retrospective comparative study.

INTRODUCTION: Several surgical techniques have been proposed for the treatment of patellar fractures. The aim of this study is to compare the clinical efficacy and complication rates of treatment using suture tape circumferential cerclage (STCC) and metallic wire circumferential cerclage (MWCC) for the surgical treatment of displaced transverse patellar fractures (TPFs). HYPOTHESIS: The hypothesis is that the use of the suture tape would be associated with a significantly lower rate of re-operation than metallic cerclage but no differences in other clinical outcomes. PATIENTS AND METHODS: A retrospective comparative analysis of the clinical outcomes of consecutive patients undergoing fixation of TPFs with either MWCC or STCC between January 2017 and December 2018 was undertaken. All patients underwent evaluation with standardised radiographs at one, three, and six months after surgery to determine rates of union, non-union, loss of fixation and malunion. All patients underwent a final clinical evaluation at 18 months postoperatively to evaluate clinical scores and complications. RESULTS: A total of 26 patients were included in the study. Thirteen patients underwent STCC and 13 underwent MWCC. There were no complications in the STCC group. In the MWCC group, one patient underwent hardware removal at 2 months postoperatively due to painful prominence. There was no significant difference in re-operation rates between the STCC and MWCC groups (p=1). There were no cases of non-union, malunion or loss of fixation throughout the series. At the final clinical follow-up of 18months, there were no significant differences in KSS, KOOS or Böstman scores between the groups. CONCLUSION: No significant differences were identified when comparing the clinical outcomes of fixation of AO/OTA 34C1/2 fractures with suture tape or metallic cerclage fixation concerning re-operation rates, union rates, loss of fixation and functional outcome measures. These results cannot be extrapolated to more complex injury patterns or surgical techniques in which prominence of implanted material is more likely. LEVEL OF EVIDENCE: III.

In-office needle arthroscopic assessment after primary ACL repair: short-term results in 15 patients.

PURPOSE: In-office needle arthroscopy has been reported as a diagnostic tool for different knee pathologies. In addition, ACL repair has seen a resurgence with the advent of innovative orthopedic devices. The aim of this study was to assess clinical, radiological, and in-office needle arthroscopic findings in 15 adult patients who underwent acute (within 14 days from injury) anterior cruciate ligament (ACL) repair. METHODS: Fifteen patients voluntarily participated in the study. A second-look arthroscopy was performed with an in-office needle arthroscopy at an average of 7.2 months after the primary repair. The parameters included in the investigation were the continuity of the anatomical footprint of the repaired ACL, subjective assessment of the ACL tension with the probe, and synovial coverage of the ACL. All patients had a Magnetic Resonance Imaging (MRI) at 6 months after repair and an arthrometric evaluation with the KT-1000. Clinical evaluation with the scores, Tegner Lysholm Knee Scoring Scale (TLKSS), the Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) was performed at the final follow-up of 2 years. Moreover, a correlation between the characteristics of ACL appearance at the time of the second look in-office needle arthroscopy, MRI and KT-1000 was performed. RESULTS: The mean TLKSS was 97.86, the mean KOOS was 98.08 and the mean subjective IKDC was 96.71. The objective IKDC was A in 10 patients and B in 5 patients. ACL healing was graded as A in 11 patients and B in 4 patients. Synovial coverage was graded as good in 10 patients and fair in 5 while MRI assessment showed a type I ACL in 10 patients, type II in 4 patients and type III in 1 patient. CONCLUSION: In-office needle arthroscopy is a reliable tool to assess the condition of a repaired ACL. In addition, ACL repair performed in acute proximal tears demonstrated excellent clinical results.

Acute Primary Repair of the Anterior Cruciate Ligament With Anterolateral Ligament Augmentation.

Acute injuries of the anterior cruciate ligament are often associated with concurrent injuries to the structures of the anterolateral complex, specifically the anterolateral ligament. Some injury patterns of the anterior cruciate ligament involve tearing of the majority of the ligament from the femoral origin, leaving a large, viable ligament remnant. In these patients, a repair of the anterior cruciate ligament back to the femoral origin can be undertaken. Subsequently, percutaneous repair of the anterolateral ligament can be performed through anatomical, percutaneous suture tape augmentation. The combined technique of anterior cruciate ligament repair with anterolateral ligament reinforcement is presented.

Combined ACL and Segond Repair in Combined Acute Proximal ACL Tears and Segond Fracture.

A renewed interest in anterior cruciate ligament preservation has been noted using arthroscopic primary repair in patients with proximal tears, but the main concern remained the control of the rotational instability. Segond fracture occurs in less than 10% of cases of acute anterolateral instability, but it can result in continued rotation instability. The aim of this study is to describe the surgical technique to acutely repair both the anterior cruciate ligament and Segond fracture in the acute setting.

Percutaneous Anterior Cruciate Ligament Repair With Needle Arthroscopy and Biological Augmentation.

Recent advancements in orthopaedic devices have instilled a renewed interest in repair of the anterior cruciate ligament. Biological augmentation of the repair has also recently been investigated with the hopes of improving repair outcomes and improving biological healing. The advent of needle arthroscopy allows for potentially decreased recovery times and potentially reduced complication rates compared with traditional arthroscopy. The purpose of this article is to present a percutaneous technique to repair the anterior cruciate ligament with suture tape augmentation while also augmenting with the biological byproducts from the native effusion using needle arthroscopy.

Segond Fractures Involve the Anterolateral Knee Capsule But Not the Iliotibial Band.

PURPOSE: To investigate the relationship between the Segond fracture and the anterolateral complex of the knee. METHODS: Between January 2014 and March 2020, patients who presented with an anterior cruciate ligament (ACL) tear requiring acute surgical reconstruction (within 10 days from trauma) were evaluated for inclusion in this study. Patients were included if they had an acute ACL tear with an associated Segond fracture (or "Segond lesion") as detected by radiograph or magnetic resonance imaging. The lateral compartment was exposed in all cases using a 5-cm lateral hockey-stick incision, which was carried down to the iliotibial band. The fascia lata was first inspected and then longitudinally divided along its fibers to expose lateral compartment. The posterolateral corner to Gerdy's tubercle anteriorly was exposed and examined. Once the Segond fracture was identified, it was recorded and photographed. RESULTS: Seventeen patients were enrolled in the study. Dissection of the Segond fracture demonstrated attachment to the anterolateral capsule only. No other discernible attachment to the Segond fracture was noted. Surgical exploration of the anterolateral knee did not reveal injury to the iliotibial band. CONCLUSIONS: Careful dissection of Segond fractures during repair revealed that there is a discernible attachment with the anterolateral capsule to the bone injury in all patients with acute ACL tears undergoing surgical reconstruction and no connections to the iliotibial band. CLINICAL RELEVANCE: The precise pathogenesis of Segond fractures has been the subject of debate, partially due to the complexity of the anatomy of the anterolateral aspect of the knee. Proper understanding of the anatomy of type IV ALL injures with Segond fractures is important to improve treatment of these injuries.

Office-Based Needle Arthroscopy: A Standardized Diagnostic Approach to the Shoulder.

In-office needle arthroscopy offers the potential advantage of reduced injury to intervention time, without the need for advanced imaging. It is particularly appropriate for those with contraindications to advanced imaging and also may reduce the risk of incorrect diagnoses in those situations in which imaging is associated with low sensitivity/specificity. The purpose of this article is to provide a standardized diagnostic approach to needle arthroscopy of the shoulder.

Non-invasive computer navigation can quantify the pivot shift maneuver with good to excellent reliability in healthy volunteers.

PURPOSE: The aim of this study was to determine the inter- and intra-observer reliability of knee laxity assessment using a non-invasive navigation system in a population of healthy young athletes. It was hypothesized that knee laxity parameters recorded using non-invasive computer navigation would demonstrate good inter- and intra-observer reliability. METHODS: Healthy volunteers aged between 18 to 30 years were recruited to the study. Static and dynamic knee laxity parameters including anterior tibial translation and tibial rotation during the pivot shift test were recorded on awake patients using non-invasive computer navigation by two independent observers: at the first visit each athlete was evaluated by the consultant and resident surgeons independently; 6 weeks after the first visit all the participants were re-tested only by the resident surgeon. Inter- and intra-observer reliability was calculated and then interpreted according to Cicchetti's criteria. RESULTS: One hundred healthy volunteers were recruited to the study, of these 38 were women (38%), and the average age was 25.5 ± 2.4 years. According to Cicchetti's criteria the intra- and inter-observer reliability for static measurements were fair for anterior tibial translation (0.572 and 0.529, respectively) and excellent for total passive tibial rotation (0.859 and 0.883, respectively). For the dynamic measurements of translation and rotation during the pivot shift maneuver both measurements demonstrated good to excellent reliability with intra and inter observer reliability ranging from 0.684 to 0.936. CONCLUSION: Non-invasive navigation for the assessment of knee laxity is associated with fair to excellent inter- and intra-observer reliability in a population of healthy volunteers.