We used immediate post-operative in vivo three-dimensional computed tomography to compare graft bending angles and femoral tunnel lengths in 155 patients who had undergone single-bundle reconstruction of the anterior cruciate ligament using the transtibial (n = 37), anteromedial portal (n = 72) and outside-in (n = 46) techniques. The bending angles in the sagittal and axial planes were significantly greater but the coronal-bending angle was significantly less in the transtibial group than in the anteromedial portal and outside-in groups (p < 0.001 each). The mean length of the femoral tunnel in all three planes was significantly greater in the transtibial group than the anteromedial portal and outside-in groups (p < 0.001 each), but all mean tunnel lengths in the three groups exceeded 30 mm. The only significant difference was the coronal graft- bending angle in the anteromedial portal and outside-in groups (23.5° vs 29.8°, p = 0.012). Compared with the transtibial technique, the anteromedial portal and outside-in techniques may reduce the graft-bending stress at the opening of the femoral tunnel. Despite the femoral tunnel length being shorter in the anteromedial portal and outside-in techniques than in the transtibial technique, a femoral tunnel length of more than 30 mm in the anteromedial portal and outside-in techniques may be sufficient for the graft to heal. . Cite this article: Bone Joint J 2014;96-B:743–51

Increasing expectations from arthroscopic anterior cruciate ligament (ACL) reconstructions require precise knowledge of technical details such as minimum intra-femoral tunnel graft lengths. A common belief of having ≥20mm of grafts within the femoral tunnel is backed mostly by hearsay rather than scientific proof. We examined clinico-radiological outcomes in patients with intra-femoral tunnel graft lengths <20 and ≥20mm. Primary outcomes were knee scores at 1-year. Secondarily, graft revascularization was compared using magnetic resonance imaging (MRI). We hypothesized that outcomes would be independent of intra-femoral tunnel graft lengths. This prospective, single-surgeon, cohort study was conducted at a tertiary care teaching centre between 2015–2018 after obtaining ethical clearances and consents. Eligible arthroscopic ACL reconstruction patients were sequentially divided into 2 groups based on the intra-femoral tunnel graft lengths (A: < 20 mm, n = 27; and B: ≥ 20 mm, n = 25). Exclusions were made for those > 45 years of age, with chondral and/or multi-ligamentous injuries and with systemic pathologies. All patients were postoperatively examined and scored (Lysholm and modified Cincinnati scores) at 3, 6 and 12 months. Graft vascularity was assessed by signal-to-noise quotient ratio (SNQR) using MRI. Statistical significance was set at p<0.05. Age and sex-matched patients of both groups were followed to 1 year (1 dropout in each). Mean femoral and tibial tunnel diameters (P =0.225 and 0.595) were comparable. Groups A (<20mm) and B (≥20mm) had 27 and 25 patients respectively. At 3 months, 2 group A patients and 1 group B patient had grade 1 Lachman (increased at 12 months to 4 and 3 patients respectively). Pivot shift was negative in all patients. Lysholm scores at 3 and 6 months were comparable (P3= 0.195 and P6= 0.133). At 1 year both groups showed comparable Cincinnati scores. Mean ROM was satisfactory (≥130 degrees) in all but 2 patients of each group (125–130 degrees). MRI scans at 3 months and 1 year observed anatomical tunnels in all without any complications. Femoral tunnel signals in both groups showed a fall from 3–12 months indicating onset of maturation of graft at femoral tunnel. Our hypothesis, clinical and radiological outcomes would be independent of intra-tunnel graft lengths on the femoral aspect, did therefore prove correct. Intra-femoral tunnel graft lengths of <20 mm did not compromise early clinical and functional outcomes of ACL reconstructions. There seems to be no minimum length of graft within the tunnel below which suboptimal results should be expected

Evaluation of transtibial aiming of the femoral tunnel at its anatomical position in arthroscopical ACL reconstruction. 43 ACL reconstructions with hamstrings’ graft were studied. First, the femoral tunnel was drilled through the anteromedial portal at 09.30–10.00 (14.00–14.30 resp.) and then the tibial tunnel (av. anteroposterior angle: 63,5°, sagittal: 64,2°) at the same diameter with simoultaneous radiological documentation. Then, with a femoral aiming device, we tried to put a K-wire at the center of the drilled femoral tunnel. Fotographic documentation took place. In 20 cases the diameter of the tunnels was 7mm, in 11, 7,5mm, in 7, 8mm, in 3, 8,5mm and in 1, 9mm. Evaluation of all radiological and photographic material from 2 observers followed, according to the deviation of the transtibial K-wire from the center of the femoral tunnel. 38 ACL reconstructions were evaluated. It was shown that in 11 cases the transtibial K-wire was in the femoral tunnel (28,9%) (in 7 with a diameter of 7mm., in 2 with 7,5mm. and in 2 with 8mm.). The K-wire was in 23 cases (60,5%) at the perimeter or out of the femoral tunnel (in 11, with a diameter of 7mm., in 8 with 7,5mm., in 4 with 8mm., in 3 with 8,5mm. and in 1 with 9mm.). There was no correlation with the angles of the tibial tunnel or the age of the patients. Transtibial aiming of the femoral tunnel at its anatomical position is very difficult and there is no correlation of the transtibial deviation with the diameter of the tibial tunnel

Correct femoral tunnel position in anterior cruciate ligament reconstruction (ACLR) is critical in obtaining good clinical outcomes. We aimed to delineate whether any difference exists between the anteromedial (AM) and trans-tibial (TT) portal femoral tunnel placement techniques on the primary outcome of ACLR graft rupture. Adult patients (>18year old) who underwent primary ACLR between January 2011 – January 2018 were identified and divided based on portal technique (AM v TT). The primary outcome measure was graft rupture. Univariate analysis was used to delineate association between independent variables and outcome. Binary logistic regression was utilised to delineate odds ratios of significant variables. 473 patients were analysed. Median age at surgery was 27 years old (range 18–70). A total of 152/473, (32.1%) patients were AM group compared to 321/473 (67.9%) TT. Twenty-five patients (25/473, 5.3%) sustained graft rupture. Median time to graft rupture was 12 months (IQR 9). A higher odds for graft rupture was associated with the AM group, which trended towards significance (OR 2.03; 95% CI 0.90 – 4.56, p=0.081). Older age at time of surgery was associated with a lower odds of rupture (OR 0.92, 95% CI 0.86 – 0.98, p=0.014). There is no statistically significant difference in ACLR graft rupture rates when comparing anteromedial and trans-tibial portal technique for femoral tunnel placement. There was a trend towards higher rupture rates in the anteromedial portal group

The purpose of this study is to identify the optimal amount of knee flexion required to drill the femoral tunnel in ACL reconstruction using the transtibial technique in order to ensure the correct alignment between the femoral tunnel and the interference screw. Methods: Twenty (10 × 2) fresh-frozen cadaveric knees were used. The native ACL was resected and its tibial attachment was identified. The angle of the tibial tunnel was set at 55° using an Arthrex tibial guide. The extra-articular tibial tunnel entry point was located at the anterior border of the superficial MCL. The intra-articular exit point of the guide wire was digitized with a digital camera and referenced to anatomical landmarks (the anterior border of the PCL, the lateral aspect of the medial spine and the anterior horn of the lateral meniscus). The femoral tunnels were made using the transtibial technique and a 5mm femoral guide to insert guidewires at 70, 80, and 90 degrees of knee flexion (groups a, b, c respectively). The angles of divergence between the longitudinal axis of the femoral tunnel and the interference screw (placed through an anteromedial portal at 120° of knee flexion) were then measured. Results: The degrees of divergence were: 5° ± 2° for group a, 12° ± 4 for group b, and 15° ± 3° for group c. Conclusions: Optimal femoral tunnel and interference screw alignment is achieved using the transtibial technique when the femoral tunnel is drilled with the knee in 70 degrees of flexion and the screw is inserted at 120 degrees of knee flexion. This study identifies a mathematical formula for the optimal amount of knee flexion required to drill the femoral tunnel in ACL reconstruction using the transtibial technique in order to ensure the correct alignement between the femoral tunnel and the interference screw

There is significant disagreement among surgeons regarding optimal placement of the femoral tunnel for anterior cruciate ligament reconstruction. Placement of the femoral tunnel via a transtibial approach usually will not allow consistent overlap between the tunnel and the anterior cruciate ligament footprint. This remains true in recent publications in spite of the fact that the tunnel center lay totally outside the femoral footprint. We have performed radiographic studies (Feller et al, 1993), cadaveric studies (Kaseta et al 2008) and currently postoperative studies showing that femoral tunnel creation is much more anatomic with an independent drilling technique. We have performed postoperative high resolution MRI exams of both knees using a protocol that reliably shows the anterior cruciate ligament footprint on the normal knee and the tunnel on the surgical knees. The centers are approximately 2mm. apart for independent techniques and 9mm. apart of the transtibially created tunnels. We are now using dual angle fluoroscopy and high resolution MRI mapping to evaluate the in vivo kinematics of knees following anterior cruciate ligament reconstruction with independent or transtibial techniques

There has been a lot of focus on the value of anatomic tunnel placement in ACL reconstruction, and the relative merits of single and double bundle grafts. Multiple cadaveric and animal studies have compared the effects of tunnel placement and graft type on knee biomechanics. 45 patients who underwent ACL reconstruction were included into our study. Femoral tunnel position was analysed by two independent doctors using the radiographic quadrant method as described by Bernard et al., and the mean values calculated. Forty-one of these patients completed a KOOS questionnaire. The mean ratio ‘a’ was 26.57% and mean ratio ‘b’ was 30.04% as compared to 24.8% (+/− 2.2%) and 28.5% (+/− 2.5%) respectively quoted by Bernard et.al, as the ideal tunnel position. Only twenty-three of these femoral tunnels were in the anatomic range. Analysis of forty-one KOOS surveys (23 anatomic, 18 non-anatomic) revealed no significant difference in total score or subscales between the anatomic and non-anatomic groups (p= >0.05). Our study suggests that the ideal tunnel position, as described by Bernard et.al. may not be ideal and fixed

Purpose. Twelve case reports of distal femur fractures as post-operative complications after anterior cruciate ligament (ACL) reconstruction have been described in the literature. The femoral tunnel has been suggested as a potential stress riser for fracture formation. The recent increase in double bundle ACL reconstructions may compound this risk. This is the first biomechanical study to examine the stress riser effect of the femoral tunnel(s) after ACL reconstruction. The hypotheses tested in this study are that the femoral tunnel acts as a stress riser to fracture and that this effect increases with the size of the tunnel (8mm versus 10mm) and with the number of tunnels (one versus two). Method. Femoral tunnels simulating single bundle (SB) hamstring graft (8 mm), bone-patellar tendon-bone graft (10 mm), and double bundle (DB) ACL reconstruction (7mm, 6 mm) were drilled in fourth generation saw bones. These three experimental groups and a control group consisting of native saw bones without tunnels, were loaded to failure. Result. All fractures occurred through the tunnels in the double tunnel group whereas fractures did not consistently occur through the tunnels in the single tunnel groups. The mean fracture load was 6145 N 471 N in the native group, 5691 N 198 N in the 8 mm single tunnel group, 5702 N 282 N in the 10 mm single tunnel group, and 4744 N 418 N in the double tunnel group. The mean fracture load for the double tunnel group was significantly different when compared to native, 8 mm single bundle, and 10 mm single bundle groups independently (p value = 0.0016, 0.0060, and 0.0038 respectively). No other statistically significant differences were identified. Conclusion. An anatomically placed femoral tunnel in single bundle ACL reconstruction in our experimental model was not a stress riser to fracture, whereas the two femoral tunnels in double bundle ACL reconstruction significantly decreased load to failure. The results support the sparcity of reported peri-ACL reconstruction femur fractures in single femoral tunnel techniques. However, the increased fracture risk in double bundle ACL reconstruction is a cause for concern and may impact patient selection

Aim. The aim of this study is to outline the steps and techniques required to create a patient specific 3D printed guide for the accurate placement of the origin of the femoral tunnel for single bundle ACL reconstruction. Introduction. Placements of the femoral tunnels for ACL reconstruction have changed over the years. Most recently there has been a trend towards placing the tunnels in a more anatomic position. There has been subsequent debate as to where this anatomic position should be. The problem with any attempt at consensus over the placement of an anatomic landmark is that each patient has some variation in their positioning and therefore a fixed point for all has compromise for all as it is an average. Our aim was to attempt to make a cost effective and quick custom guide that could allow placement of the center of the patients’ newly created femoral tunnel in the mid position of their contralateral native ACL femoral footprint. Materials & Methods. We took a standard protocol MRI scan of a patient's knee without ACL injury transferred the DICOM files to a personal computer running OsiriX (Pixmeo, Geneva, Switzerland.) and analysed it for a series of specific anatomical landmarks. OsiriX is an image processing software dedicated to DICOM images. We marked the most posterior edge of the articular cartilage on the lateral wall of the notch (1), the most anterior edge of the articular cartilage of the lateral wall of the notch (2), the most inferior edge of the articular cartilage of the lateral wall of the notch (3) and the center of the femoral footprint of the native ACL. Distances were then calculated to determine the position relative to the three articular cartilage points of the center of the ACL footprint. These measurements and points were then utilised to create a 3D computer aided design (CAD) model of a custom guide. This was done using the 3D CAD program 123Design (Autodesk Ltd., Farnbourgh, Hampshire). This 3D model was then exported as an STL file suitable for 3D printing. The STL file was then uploaded to an online 3D printing service and the physical guide was created in transparent acrylic based photopolymer, PA220 plastic and 316L stainless steel. The models created were then measured using vernier calipers to confirm the accuracy of the final guides. Results. The MRI data showed point 1 (AP), point 2 (distal-ACL), point 3 (Ant-ACL) and point 4 (Post-ACL) at a distance of 59.83, 15, 45.8 and 13.9 respectively. For the 3D CAD model, points 1, 2, 3 and 4 were at a distance of 59.83, 15, 45.8 and 13.9 respectively. For the PA220 plastic model, points 1, 2, 3 and 4 were at a distance of 59.86, 14.48, 45.85 and 13.79 respectively. For the 316L stainless steel model, points 1, 2, 3 and 4 were at a distance of 59.79, 14.67, 45.64 and 13.48 respectively. Lastly, for the photopolymer model, points 1, 2, 3 and 4 were at a distance of 59.86, 14.2, 45.4 and 13.69 respectively. The p-value comparing MRI/CAD vs. PA220 was p=0.3753; for the comparison between MRI/CAD vs. 316L, p=0.0683; lastly for the comparison between MRI/CAD Vs. Photopolymer, p=0.3450. The models produced were accurate with no statistical difference in size and positioning of the center of the ACL footprint from the original computer model and to the position of the ACL from the MRI scans. The costs for the models 3D printed were £3.50 for the PA220 plastic, £15 for the transparent photopolymer and £25 for the 316L stainless steel. The time taken from MRI to delivery for the physical models was 7 days. Discussion. Articles regarding the creation of 3D printed custom ACL guides from the patients contralateral knee do not feature in current literature. There has been much research on custom guides for other orthopaedic procedures such as in total knee arthroplasty for the accurate placement of implants. There has also been research published on the creation of custom cutting jigs from CT for complex corrective osteotomy surgery. This study serves as the first step and a proof of concept for the accurate creation of patient specific 3D printed guides for the anatomical placement of the femoral tunnel for ACL reconstruction. The guides were easy to create and produce taking only a week and with a cost of between £3.50 and £25. The design of the guides was to allow the tip of a standard Chondro Pick (Arthrex inc., Naples, Florida.) (3mm) used to mark the starting point of the femoral tunnel to enter through the guide. The next step for this research is to create guides from cadaveric matched knees and utilise the guides to carry out the creation of the femoral tunnels and to analyse of the placement of the tunnel in relation to the contralateral knee

Background. Recent publications have supported the anatomic placement of anterior cruciate grafts to optimise knee function. However, anatomic placement using the anteromedial portal has been shown to have a higher failure rate than traditional graft placement using the transtibial method. This is possibly due to it being more technically difficult and to the short femoral tunnel compromising fixation methods. It also requires the knee to be in hyper flexion. This position is not feasible during with a tourniquet in situ on the heavily muscled thighs of some athletes. Hypothesis: That navigation can be used to place the femoral tunnel in the anatomic position via a more medial transtibial tunnel. Methods. 25 patients underwent Navigated Anterior Cruciate reconstruction with quadruple hamstring grafts. The Orthopilot™ 3.0 ACL (BBraun Aesculap, Tuttlingen) software was used. The femoral and tibial ACL footprints were marked on the bones with a radio frequency probe and registered. The pivot shift test, anterior drawer and internal and external rotation were registered. A navigated tibial guide wire was inserted at 25° to the sagittal plane and 45° to the transverse plane exiting through the centre of the tibial footprint. The guide wire was advanced into the joint to just clear of the surface of the femoral footprint with the knee in 90° flexion. Flexion/extension of the knee was done to determine the closest position of the guide wire tip to the centre of the anatomical femoral footprint. If the tip was within 2mm of the centre of footprint, the position was accepted. If not the tibial guide wire was repositioned and the process repeated. The tibial tunnel was drilled, followed by transtibial drilling of the femoral tunnel. A screen shot was done to allow determination of the shape and area of the tunnel aperture relative to the femoral footprint using ImageJ (National Institute of Health). The graft was fixed proximally with an Arthrex ACL Tightrope® and distally with a Genesys™ interference screw. The pivot shift test, anterior drawer and internal and external rotation were repeated and recorded using the software. Results. In 22 out of 25 patients the centre of the drill hole was within 2mm of the centre of the anatomic femoral footprint. In 3 patients it was between 2 and 4 mm off centre. The femoral tunnel diameter ranged from 7.5mm to 9.5mm. In 23 knees there was more than 80 % overlap between the tunnel aperture and the anatomical footprint. In the other 2 knees there was 65% and 75% overlap respectively. The direction of the final tibial tunnel ranged from 22° to 28° from the sagittal plane and 42° to 49° from the transverse plane. The optimum knee flexion was between 76° and 94°. In all cases, the pivot shift recorded by the software was absent after graft fixation. There was a statistically significant difference between the anterior drawer, internal and external rotation before and after graft fixation (p<0.05). Conclusion. Based on our data, navigation allows reproducible transtibial anatomic placement of the quadruple hamstring ACL graft. This is possible when the position of the tibial tunnel is customised to the anatomy of the individual patient's knee

Medial portal reaming may allow for the creation of a more anatomically positioned femoral tunnel during Anterior Cruciate Ligament (ACL) reconstruction. However, this technique also results in a shorter tunnel which may make fixation difficult. The purpose of this study is to determine the average length of a femoral tunnel created using a medial portal technique and to correlate this with patient gender, height and Body Mass Index (BMI). Fifty-four consecutive patients underwent ACL reconstruction with a femoral tunnel created using a medial portal technique. The tunnels were created using a spade tip guide pin (Arthrex, Naples, FL) with the goal of creating the tunnel in the 2-2:30 o'clock position (left knee) or 9:30-10 o'clock position (right knee). The total osseous length of the femur (TOL) was measured using a depth gauge. Descriptive statistics of the TOL were calculated and bivariate correlation coefficients (Pearson r) were calculated to determine the relationship between TOL and patient height and weight. The mean TOL was found to be 33.77 ± 5.27 mm (24-50 mm). TOL was found to correlate with patient height (r=0.32, r. 2. =0.10, p=0.04) and was not correlated to weight (r=0.24, r. 2. =0.06, p=0.15) or BMI (r=0.06, r. 2. =0.004, p=0.7). Men had a greater TOL (34.91 ± 5.4) than women (32.13 ± 4.80) but this difference was not found to be statistically significant (p=0.10). ACL reconstruction using a medial portal yields a mean total osseous length of 33.77 mm. This length is significantly correlated with patient height. ACL reconstruction using a medial portal approach to femoral reaming can lead to tunnels as short as 24 mm. Patient height may be a useful clinical tool to indicate the potential for a short femoral tunnel

Hypothesis. Recent advances in understanding of ACL insertional anatomy has led to new concepts of anatomical positioning of tunnels for ACL reconstruction. Femoral tunnel position has been defined in terms of the lateral intercondylar ridge and the bifurcate ridge but these can be difficult to identify at surgery. Measurements of the lateral wall either using C-arm x-ray control or specific arthroscopic rulers have also been advocated. Method. 30 patients undergoing ACL reconstruction before and after introduction of a new anatomical technique of ACL reconstruction were evaluated using 3D CT scan imaging with cut away views of the lateral aspect of the femoral notch and the radiological quadrant grid. In the new technique, with the knee at 90 degrees flexion, the femoral tunnel was centred 50% from deep to shallow as seen from the medial portal (Group A). Group B consisted of patients where the femoral tunnel was drilled through the antero-medial portal and offset from the posterior wall using a 5mm jig. Results. Ridges were identifiable in only 76% of scans. All tunnels in Group A (anatomical technique) were found to be below (posterior to) the lateral intercondylar (residents) ridge and were within 10% of the optimal position as defined by the Grid method on x-ray. No femoral tunnels in Group B meet anatomical criteria and were malpositioned by a mean of 5mm. Conclusion. We believe 3D CT scan imaging with cut away views of the femoral tunnel is a useful and accurate way of describing tunnel position, and that this technique will be valuable in validating new surgical techniques. According to this CT scan analysis the new anatomical technique correctly placed the femoral tunnel. This work forms the basis of a subsequent randomised trial of techniques in relation to clinical outcome

Introduction. The transtibial approach is widely used for femoral tunnel positioning in ACL reconstruction. Controversy exists over the superiority of this approach over others. Few studies reflected on the reproducibility rates of the femoral tunnel position in relation to the approach used. Methods. We reviewed AP and Lat X-ray radiographs post isolated ACL reconstruction for 180 patients for femoral tunnel position, tibial tunnel position and graft inclination angle. All patients had their operations performed by one surgeon in one hospital between March 2006 and Sep 2010. All operations were performed using one standard technique using transtibial approach for femoral tunnel positioning. Two orthopaedic fellows, with similar experiences, reviewed blinded radiographs. A second reading was done 8 weeks later. Pearson inter-observer and intra-observer correlation analyses were done using SPSS. Mean age was 29 years (range 16–54). Results. Pearson intra-observer correlation shows substantial to perfect agreement while Pearson's inter-observer correlation shows moderate to substantial agreement. Previous literature proved that optimal femoral tunnel position for the best clinical and biomechanical outcome is for the centre of the tunnel to be at 43% from the lateral end of the width of the femoral condyles on the AP view and at 86% from the anterior end of the Blumensaat's line on the lateral view. In our study 85% of the femoral tunnels were within +/− 5% of the optimal tunnel position on the AP views (43%), and more than 70% of the femoral tunnels were within +/−5% of the optimal tunnel position on the Lateral view (86%). Conclusion. Based on our results we concluded that using one standardised transtibial technique for ACL reconstruction can result in high reproducibility rates of optimal femoral tunnel position. Further studies are needed to validate our results and to study the reproducibility rates for different approaches and techniques

The transtibial approach is widely used for femoral tunnel positioning in ACL reconstruction. Controversy exists over the superiority of this approach over others. Few studies reflected on the reproducibility rates of the femoral tunnel position in relation to the approach used. We reviewed AP and Lat X-ray radiographs post isolated ACL reconstruction for 180 patients for femoral tunnel position, tibial tunnel position and graft inclination angle. All patients had their operations performed by one surgeon in one hospital between March 2006 and Sep 2010. All operations were performed using one standard technique using transtibial approach for femoral tunnel positioning. Two orthopaedic fellows, with similar experiences, reviewed blinded radiographs. A second reading was done 8 weeks later. Pearson inter-observer, intra-observer correlation and Bland-Altman agreements plots statistical analyses were done. Mean age was 29 years (range 16–54), Pearson intra-observer correlation shows substantial to perfect agreement while Pearson's inter-observer correlation shows moderate to substantial agreement. Previous literature proved that optimal femoral tunnel position for the best clinical and biomechanical outcome is for the centre of the tunnel to be at 43% from the lateral end of the width of the femoral condyles on the AP view and at 86% from the anterior end of the Blumensaat's line on the lateral view. In our study 85% of the femoral tunnels were within +/− 5% of the optimal tunnel position on the AP views, and more than 70% of the femoral tunnels were within +/−5% of the optimal tunnel position on the Lateral view. Interobserver and intraobserver corelations show moderate to substantial agreement, Bland-Altman agreement plots show substantial agreements for interobserver and intraobserver measurements. These results were found to be statistically significant at 0.01. Based on our results we conclude that using one standardised transtibial technique for ACL reconstruction can result in high reproducibility rates of optimal femoral tunnel position. Further studies are needed to validate our results and to study the reproducibility rates for different approaches and techniques

Aim: To determine optimal tibial tunnel orientation that projected onto isometric positions of the LFC. Methods: Tibial tunnels were described by transverse rotations about tibial long axes, angles of elevation and tilt. In each of 8 cadaver knees, 18 tibial positions were drilled with 2mm wires to exit at the centre and posterior end of the tibial footprint. The linear projections of these wires onto the LFC were marked by 1.6mm wires and were described as x-y co-ordinates with reference to the geometric centre of the LFC. Results: The isometric femoral tunnel positions were approximated (within a 2mm radius) by tibial tunnels rotated 39.3°, elevated 55.7°, exiting at the posterior end of the footprint with knees flexed 90°. Tunnels rotated between 20–45° and elevated 60° had highest probability of isometric projection and those that exited at the centre of the footprint could not be linearly projected anywhere near the isometric point. Applying 50N posterior force on the tibia brought the projections proximally by 4.1mm (p=0.001). Conclusion: Transtibial tunnel directions are known to affect siting of femoral tunnels, and hence outcome of ACL surgery. This study demonstrated the orientation of tibial tunnels that could linearly project to isometric femoral tunnel positions

Aim: To evaluate whether a guiding pin for a femoral tunnel could be positioned through the tibial tunnel into the center of the anatomical ACL attachment. Methods: 77 knees underwented arthroscopic ACL reconstruction with hamstrings. The femoral tunnel was drilled through an anteromedial portal at the center of the anatomic insertion at about 10.00 resp.14.00 position. Tibial tunnel (mean diameter 7.55 ± 0.54 mm) was drilled using a guide inserted at 90 degrees of knee flexion. Then, through the tibial tunnel, a 4mm offset femoral drill guide was positioned as close as possible to the femoral tunnel and a 2.5 mm guide wire was drilled. The position of the guide wire was photographed arthroscopically and the deviation was measured as the distance between the center of the femoral tunnel and the guide wire. Results: The mean deviation was 4.50 ± 1.54 mm (p = 0.00000004) In 74 knees (96.1%) the guidewire did not reach the femoral tunnel. Only in 3 knees it reached the superomedial edge of the femoral tunnel. No statistical relationship was found between deviation and tibial tunnel inclination angles or tibial tunnel diameter. Conclusions: Transtibial femoral tunnel drilling does not reach the anatomic site of the ACL insertion, even with larger tibial tunnels (for hamstring grafts up to 8.5 mm). Transtibial tunnel drilling should be replaced by drilling through the anteromedial portal at least for tunnels with diameters < 9 mm

Abstract. The radiographic or bony landmark techniques are the two most common methods to determine Medial patellofemoral ligament (MPFL) femoral tunnel placement. Their intra/inter-observer reliability is widely debated. The palpation technique relies on identifying the medial epicondyle (ME) and adductor Tubercle (AT). The central longitudinal artery and associated vessels (CLV) are consistently seen in the surgical dissection during MPFL reconstruction. The aim of this study was to investigate the anatomic relationship of CLV to ME-AT and thereby use CLV as an important vascular landmark during MPFL reconstruction. A retrospective review of MRI scans in skeletally mature patients presenting to a tertiary referral knee clinic was undertaken. Group-N consisted of any presentation without patellofemoral instability or malalignment (PFI). Group-P with PFI. MRI's were reviewed and measured by two Consultant Radiologists for the CLV-ME-AT anatomy and relationship. Following exclusions 50 patients were identified in each group. The CLV passed anterior to the AT and ME in all patients. ME morphology did not differ greatly between the groups except in the tubercle height, where there was a statically but not clinically significant difference (larger in the non-PFI group, 2.95mm vs 2.52mm, p=0.002). The CLV to ME Tip distance was consistent between the groups (Group PFI group 3.8mm & ‘normal’ non-PFI Group 3.9mm). The CLV-ME-AT relationship remained consistent despite patients presenting pathology. The CLV consistently courses anterior to ME and AT. The CLV could be used as a vascular landmark assisting femoral tunnel placement during MPFL reconstruction

Aim. The aim of this study is to outline the steps and techniques required to create a patient specific 3D printed guide for the accurate placement of the origin of the femoral tunnel for single bundle ACL reconstruction. Introduction. Placements of the femoral tunnels for ACL reconstruction have changed over the years 1,2. Most recently there has been a trend towards placing the tunnels in a more anatomic position. There has been subsequent debate as to where this anatomic position should be 3. The problem with any attempt at consensus over the placement of an anatomic landmark is that each patient has some variation in their positioning and therefore a fixed point for all has compromise for all, as it is an average 4. Our aim was to attempt to make a cost effective and quick custom guide that could allow placement of the center of the patients’ newly created femoral tunnel in the mid position of their contralateral native ACL femoral footprint. Materials & Methods. We took a standard protocol MRI scan of a patient's knee without ACL injury transferred the DICOM files to a personal computer running OsiriX (Pixmeo, Geneva, Switzerland.) and analyzed it for a series of specific anatomical landmarks (fig1). These measurements and points were then utilized to create a 3D computer aided design (CAD) model of a custom guide. This was done using the 3D CAD program 123Design (Autodesk Ltd., Farnbourgh, Hampshire). This 3D model was then uploaded to an online 3D printing service and the physical guide was created in transparent acrylic based photopolymer, PA220 plastic (fig 2) and 316L stainless steel. The models created were then measured using vernier calipers to confirm the accuracy of the final guides. The models produced were accurate with no statistical difference in size and positioning of the center of the ACL footprint from the original computer model and to the position of the ACL from the MRI scans. The costs for the models 3D printed were £3.50 for the PA220 plastic, £15 for the transparent photopolymer and £25 for the 316L stainless steel. The time taken from MRI to delivery for the physical models was 7 days. Conclusion. This study serves as the first step and a proof of concept for the accurate creation of patient specific 3D printed guides for the anatomical placement of the femoral tunnel for ACL reconstruction. The guides were easy to create and produce taking only a week and with a cost of between £3.50 and £25

Anterior cruciate ligament (ACL) injuries are one of the most common ligament injury occurring in young and active individuals. Reconstruction of the torn ligament is the current standard of care. Of the many factors which determine the surgical outcome, fixation of the graft in the bony tunnels has significant role. This study compared the clinical and functional outcome in patients who underwent ACL reconstruction by standard anteromedial portal technique with single bundle hamstring graft anchored in the femoral tunnel using rigidfix and cortical button with adjustable loops. The tibial fixation and rehabilitation protocol were same in both groups. 107 patients underwent ACL reconstruction over a two-year period (87 males, 20 females, 44 after motor vehicle accident, 34 after sports injuries, 79 isolated ACL tear, 21 associated medial meniscus tear, 16 lateral meniscus tear and 11 both menisci). Rigid fix group had 47 patients and adjustable loop 60 patients. Clinical evaluation at end of one year showed better stability in rigid fix group regarding Lachman, anterior drawer, pivot shift tests, KT 1000 arthrometer side to side difference and hop limb symmetry index. However, the differences were not statistically significant. Functional evaluation using IKDC 2000 subjective score and Lysholm score showed better results in rigidfix group than variable loop, but was not statistically significant. However, lower scores were noted in patients with concomitant meniscal injury than in isolated acl tear patients and this was statistically significant in both groups. Rigidfix seems to give better graft fixation on femoral side than variable loop, but by the end of one year the functional outcome is comparable in isolated acl reconstructions

Purpose. The purpose of this study was to determine whether intra-operative identification of osseous ridge anatomy (lateral intercondylar “residents” ridge and lateral bifurcate ridge) could be used to reliably define and reconstruct individuals' native femoral ACL attachments in both single-bundle (SB) and double-bundle (DB) cases. Methods. Pre-and Post-operative 3D, surface rendered, CT reconstructions of the lateral intercondylar notch were obtained for 15 patients undergoing ACL reconstruction (11 Single bundle, 4 Double-bundle or Isolated bundle augmentations). Morphology of native ACL femoral attachment was defined from ridge anatomy on the pre-operative scans. Centre's of the ACL attachment, AM and PL bundles were recorded using the Bernard grid and Amis' circle methods. During reconstruction soft tissue was carefully removed from the lateral notch wall with RF coblation to preserve and visualise osseous ridge anatomy. For SB reconstructions the femoral tunnel was sited centrally on the lateral bifurcate ridge, equidistant between the lateral intercondylar ridge and posterior cartilage margin. For DB reconstructions tunnels were located either side of the bifurcate ridge, leaving a 2mm bony bridge. Post-operative 3D CTs were obtained within 6 weeks post-op to correlate tunnel positions with pre-op native morphology. Results. Pre-op native ACL attachment site morphology was very similar to previous in-vitro studies: the mean centre was found at 27% along Blumensaat's line (range 19-33%) and 38% the width of the lateral femoral condyle (range 31-43%). Despite the variability between individuals there was close correlation between pre-operative localization of the femoral attachment centre and position of single bundle ACL reconstructions tunnels on the post-op CT (R=0.92). Similar results were observed for double-bundle and isolated bundle augment reconstructions. Conclusion. ACL attachment site morphology varies between individuals. Intra-operative localization of the osseous landmarks (lateral intercondylar and bifurcate ridges) appears to lead to accurate, individualised anatomical tunnel placement whether using single or double-bundle reconstruction techniques