Center Of Footprint Research Articles

Qualitative and Quantitative Anatomy of the Proximal Humerus Muscle Attachments and the Axillary Nerve: A Cadaveric Study

To provide a quantitative and qualitative anatomic analysis of the pectoralis major, teres major, and latissimus dorsi on the humerus, as well as the deltoid tendinous attachments on the proximal humerus and acromion, and to quantitatively characterize the humeral course of the axillary nerve. Ten nonpaired, fresh-frozen human cadaveric shoulders were analyzed. A portable coordinate-measuring device quantified the location of bony landmarks and tendon attachment areas. The tendon footprints were recorded by tracing their outlines and center points. The footprint areas of the tendons, the distances between the footprint areas and pertinent osseous and soft-tissue landmarks, and the distance between where the axillary nerve courses across the humerus relative to the acromion and greater tuberosity were measured. Of the 10 specimens, 9 (90%) had 5 distinct tendinous bands attaching the deltoid to the acromion; 1 specimen had 4 bands. The distances between the center of the deltoid footprint on the humerus and the centers of the pectoralis major, latissimus dorsi, and teres major tendon footprints on the humerus were 43.5mm, 58.5mm, and 49.4mm, respectively. The shortest distances from the perimeter of the pectoralis major to the latissimus dorsi and teres major tendon footprints were 3.9mm and 9.5mm, respectively. The distance from the superior aspect of the greater tuberosity to the axillary nerve on the humeral shaft was 50.3mm (95% confidence interval, 47.0-53.5mm). The distance from the lateral acromion to the axillary nerve was 69.3mm (95% confidence interval, 64.1-74.5mm). The deltoid muscle had 4 to 5 tendinous insertions on the acromion, and the axillary nerve was 50.3mm from the tip of the greater tuberosity. The distance between the lower border of the pectoralis major and the axillary nerve was 9.4mm. Knowledge of the quantitative anatomy of the tendons of the proximal humerus and axillary nerve can aid in identifying structures of interest during open shoulder surgery and in avoiding iatrogenic axillary nerve injury. Furthermore, this study provides direction to avoid injury to the deltoid tendons during open surgery.

Three-Dimensional Evaluation of Similarity of Right and Left Knee Joints.

PurposeThe purpose of this study was to evaluate the anatomical similarity of three-dimensional (3D) morphometric parameters between right and left knees.Materials and MethodsTen fresh-frozen paired cadaveric knees were tested. Following dissection, footprint areas of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) were measured. Surface scanning was performed using a 3D scanner. Scanned data were reproduced and morphometric parameters were measured on specialized software. After making mirror models, we compared footprint center positions of the ACL and PCL of both sides and calculated the average deviation of 3D alignment between the right- and left-side models.ResultsNo significant side-to-side differences were found in any morphometric parameters. Bony shapes displayed a side-to-side difference of <1 mm. Distal femoral and proximal tibial volumes did not present side-to-side differences, either; the average 3D deviations of alignment between the right and left sides were 0.8±0.4/1.1±0.6 mm (distal femur/proximal tibia). Center-to-center distances between the right and left ACL footprints were 2.6/2.7 mm (femur/tibia) for the anteromedial bundle and 2.4/2.8 mm for the posterolateral bundle. They were 1.9/1.5 mm for the anterolateral bundle and 2.2/1.8 mm for the posteromedial bundle of the PCL.ConclusionsThere was a remarkable 3D morphometric similarity between right and left knees. Our results might support the concept of obtaining morphologic reference data from the uninvolved contralateral knee.

Variations in sagittal locations of anterior cruciate ligament tibial footprints and their association with radiographic landmarks: a human cadaveric study

BackgroundThis cadaveric study aimed to demonstrate variation of the anterior cruciate ligament (ACL) tibial attachment in the sagittal plane, and to analyze the radiographic landmarks which predict the sagittal location of the ACL tibial attachment.MethodsIn 20 cadaveric knees, native ACLs were removed and the centers of the ACL tibial and femoral attachments were marked with metal pins. Full extension lateral radiographs were then obtained in each cadaveric knee. Using the full extension lateral radiographs, the sagittal location of the ACL tibial footprint center was estimated as a percentage in the Amis and Jakob’s line. Several radiographic landmarks including the geometry of Blumensaat’s line and the apex of the tibial eminence were measured. Then, the relationship between the variation of the sagittal location of the ACL tibial footprint and several radiographic landmarks were analyzed using Pearson’s correlation analysis.ResultsThe average sagittal position of the native ACL tibial footprint was 40.9% (range: 38.0–45.0%). The line connecting the centers of the ACL footprint was nearly parallel to Blumensaat’s line, with an average angle of 1.7° (range: 0–4.1°). In addition, the distance from the point where Blumensaat’s line meets the tibial articular surface to the center of the ACL tibial footprint was almost consistent, at 7.6 mm on average (range: 6.4–8.7 mm). The correlation analysis revealed that the geometry of Blumensaat’s line was significantly correlated with the sagittal location of the ACL tibial footprint.ConclusionThe radiographic landmark that showed a significant correlation with the ACL tibial footprint in the full extension lateral radiographs was Blumensaat’s line.

A Prospective Evaluation of Femoral Tunnel Placement for Anatomic Anterior Cruciate Ligament Reconstruction Using 3-Dimensional Magnetic Resonance Imaging

Background: The recent emphasis on anatomic reconstruction of the anterior cruciate ligament (ACL) is well supported by clinical and biomechanical research. Unfortunately, the location of the native femoral footprint can be difficult to see at the time of surgery, and the accuracy of current techniques to perform anatomic reconstruction is unclear. Purpose: To use 3-dimensional magnetic resonance imaging (3D MRI) to prospectively evaluate patients with torn ACLs before and after reconstruction and thereby assess the accuracy of graft position on the femoral condyle. Study Design: Cohort study; Level of evidence, 3. Methods: Forty-one patients with unilateral ACL tears were recruited into the study. Each patient underwent 3D MRI of both the injured and uninjured knees before surgery. The contralateral (uninjured) knee was used to define the patient’s native footprint. Patients then underwent ACL reconstruction, and the injured knee underwent reimaging after surgery. The location and percentage overlap of the reconstructed femoral footprint were compared with the patient’s native footprint. Results: The center of the native ACL femoral footprint was a mean 12.0 ± 2.6 mm distal and 9.3 ± 2.2 mm anterior to the apex of the deep cartilage. The position of the reconstructed graft was significantly different, with a mean distance of 10.8 ± 2.2 mm distal (P = .02) and 8.0 ± 2.3 mm anterior (P = .01). The mean distance between the center of the graft and the center of the native ACL femoral footprint (error distance) was 3.6 ± 2.6 mm. Comparing error distances among the 4 surgeons demonstrated no significant difference (P = .10). On average, 67% of the graft overlapped within the native ACL femoral footprint. Conclusion: Despite contemporary techniques and a concerted effort to perform anatomic ACL reconstruction by 4 experienced sports orthopaedic surgeons, the position of the femoral footprint was significantly different between the native and reconstructed ACLs. Furthermore, each surgeon used a different technique, but all had comparable errors in their tunnel placements.

Novel Anatomical Single Bundle ACL Reconstruction Using a Rounded Rectangular Dilator

We have designed and developed an original rounded rectangular dilators and sizing block to perform novel anatomical single bundle ACL reconstruction. Compared with conventional anatomical single bundle ACL reconstruction, rounded rectangular femoral tunnel ACL reconstruction created a large femoral tunnel and improved anteroposterior, rotational laxity and clinical results. During the past 10 years, the main trend for ACL reconstruction has shifted to anatomic reconstruction, regardless of single bundle or double bundle techniques. There is no significant difference in the postoperative stability and clinical results between single and double bundle ACL reconstruction. Therefore, attention has returned to single bundle reconstruction with grafts that are placed at the center of anatomical footprint. It is widely accepted that the smaller hamstring autograft size (tunnel diameter < 8mm) is a predictor of poorer clinical results. However, the shortcoming of conventional anatomical single bundle ACL reconstruction is that the creation of a large anatomical bone tunnel is not possible because of roof impingement or breakage of posterior femoral bone tunnel. Furthermore several anatomical studies have reported that the femoral insertion of the ACL has a rounded rectangle shape, and we have also realized that the quadrupled semitendinosus tendons appear to be a rounded rectangular, rather than circular. Therefore, we created an original femoral dilator and sizing block and developed a new ACL reconstruction technique: “rounded rectangular femoral tunnel ACLR” (RFTR). This study aimed to compare the area of femoral tunnel and clinical results between conventional anatomical single bundle ACL reconstruction (ASBR) and RFTR. The hypothesis was that RFTR could have a larger femoral tunnel and improve clinical results. Between May 2010 and Aug. 2015, 157 primary ACL reconstructions were performed. After implementation of inclusion criteria, 116 ACL reconstructions were analyzed (ASBR = 57 patients, 25 male, 32 female; age, 24.1±9.3 years; RFTR = 59 patients, 34 male, 25 female; age, 24.5±10.1 years). Both ACL reconstructions were performed using a semitendinosus graft (with or without the gracilis tendon). The evaluation items were area of the femoral tunnel, anteroposterior laxity with KT-1000, pivot-shift test, and Lysholm score. We determined the femoral tunnel size using a sizer during arthroscopy. The tunnel exists within the native ACL footprint, and we chose the maximum size possible without going beyond the lateral intercondylar ridge. RFTR created a bigger femoral tunnel area than did ASBR (average area, 52.7±4.8 mm2 vs 47.0±7.3 mm2; P<0.01). RFTR resulted in better anteroposterior stability and Lysholm score than did ASBR (average side-to-side difference for anterior tibial translation, 0.8±1.1 mm vs 1.8±1.2 mm; P<0.01); average Lysholm score, 98.9±2.4 vs 97.6±3.3; P<0.01). Differences in rotational laxity between groups were statistically significant (negative pivot shift, 93.3% vs 82.5%; P<0.01). Compared with conventional anatomical single bundle ACL reconstruction, rounded rectangular femoral tunnel ACL reconstruction created a large femoral tunnel and improved anteroposterior, rotational laxity and clinical results. This technique simple and can address the shortcomings of conventional anatomical single bundle ACL reconstruction.

Morphological changes in tibial tunnels after anatomic anterior cruciate ligament reconstruction with hamstring tendon graft

BackgroundThree-dimensional (3D) reconstructed computed tomography (CT) is crucial for the reliable and accurate evaluation of tunnel enlargement after anterior cruciate ligament (ACL) reconstruction. The purposes of this study were to evaluate the tibial tunnel enlargement at the tunnel aperture and inside the tunnel and to clarify the morphological change at the tunnel footprint 1 year after the anatomic triple-bundle (ATB) ACL reconstruction using 3D CT models.MethodsEighteen patients with unilateral ACL rupture were evaluated. The ATB ACL reconstruction with a semitendinosus tendon autograft was performed. 3D computer models of the tibia and the three tibial tunnels were reconstructed from CT data obtained 3 weeks and 1 year after surgery. The cross-sectional areas (CSAs) of the two anterior and the one posterior tunnels were measured at the tunnel aperture and 5 and 10 mm distal from the aperture and compared between the two periods. The locations of the center and the anterior, posterior, medial, and lateral edges of each tunnel footprint were also measured and compared between the two periods.ResultsThe CSA of the posterior tunnel was significantly enlarged at the aperture by 40.4%, whereas that of the anterior tunnels did not change significantly, although the enlargement rate was 6.1%. On the other hand, the CSA was significantly reduced at 10 mm distal from the aperture in the anterior tunnels. The enlargement rate in the posterior tunnel was significantly greater than that in the anterior tunnels at the aperture. The center of the posterior tunnel footprint significantly shifted postero-laterally. The anterior and posterior edges of the posterior tunnel footprint demonstrated a significant posterior shift, while the lateral edge significantly shifted laterally. There was no significant shift of the center or all the edges of the anterior tunnels footprint.ConclusionsThe posterior tibial tunnel was significantly enlarged at the aperture by 40% with the morphological change in the postero-lateral direction reflected by the ACL fiber orientation 1 year after the ATB ACL reconstruction. The proper tibial tunnel location in the ACL reconstruction should be determined considering the tunnel enlargement in postero-lateral direction after surgery.

Stump Incorporation for Anterior Cruciate Ligament Reconstruction: A Step Towards a More Anatomical Reconstruction

In most anterior cruciate ligament (ACL) tears, the tear is at the femoral side leaving a robust stump attached to the tibia. Stump-preserving ACL reconstruction carries the advantage of rapid reinnervation and revascularization of the graft. In this technique, the femoral tunnel is created after exposing the femoral footprint. The ACL tibial stump is split and the tip of the ACL tibial guide is introduced through this split to reach the center of the tibial footprint. The tibial tunnel is then created and the ACL stump is bored to allow the passage of the graft. After the passage of the graft inside the stump and femoral and tibial fixation, 1 or 2 sutures are used to suture the graft to the stump by a suture passing device (Expressew II; Depuy Mitek, Raynham, MA). This technique, in addition to preservation of the mechanoreceptors and vascular channels for revascularization and reinnervation of the graft, allows preservation of the shape and surface area of the wide tibial origin of the ACL.

Anatomic tunnel placement can be achieved with a modification to transtibial technique in single bundle anterior cruciate ligament reconstruction: A cadaver study.

Placing the tunnels in the anatomic positions is important for successful restoration of knee function after anterior cruciate ligament reconstruction (ACLR). It has been shown that it is difficult to place the tunnels in the anatomic position using the transtibial technique. The purpose of this study was to evaluate the effect of each step of our modified transtibial technique (mTT) on the positioning of the femoral tunnel so as to assess whether the mTT could achieve anatomic placements of the tunnels without tibial tunnel expansion. Ten fresh-frozen cadaveric knees were used. First, the tibial tunnel was created in the center of ACL footprint. Then, a pin was inserted through the tibial tunnel using a femoral guide by four stepwise techniques: transtibial technique, additional anterior drawer force applied to the proximal tibia, another additional varus force applied to the tibia and finally, additional external rotation of the tibia and the femoral guide (mTT). Then, tibial tunnel was re-reamed using mTT with 10mm-diameter reamer. The pin positions in each technique on the femur were evaluated by the quadrant method and shapes of the tibial tunnel apertures were evaluated. Femoral pin positions in the four techniques were 23.6±4.5%, 28.4±3.4%, 30.1±3.8%, 33.2±4.5% in the superior-inferior position, and 23.9±4.3%, 26.2±3.7%, 32.0±4.3%, 36.9±4.8% in the anterior-posterior position, respectively. Pin position shifted to more inferior and posterior position with each step of mTT (all p values comparing superior-inferior and anterior-posterior positions of each step with positions of previous step were 0.008 or less). Using mTT, tibial tunnel aperture was 10.5±0.3mm wide and 12.9±1.1mm long. In conclusion, anatomic placements of femoral tunnels in ACLR without excessive tibial tunnel expansion could be achieved using the mTT.

Anatomic Anterior Cruciate Ligament Reconstruction - A Prospective Evaluation Using Three-Dimensional Magnetic Resonance Imaging

Objectives:The recent emphasis on anatomic reconstruction of the anterior cruciate ligament (ACL) is well supported by clinical and biomechanical research. Unfortunately, the location of the native femoral footprint can be difficult or even impossible to see at the time of surgery. Most surgeons therefore rely on anatomic landmarks, custom drill guides, or general rules-of-thumb to guide femoral tunnel placement; however, the accuracy of these techniques to reconstruct each patient’s native anatomy is poorly understood. The objective of this study was to use a previously described isotropic magnetic resonance sequence (3D MRI) to image patients with torn ACLs before and after reconstruction and thereby assess the accuracy of graft position on the femoral condyle in comparison to each patient’s native ACL footprint.Methods:Forty-one patients with unilateral ACL tears were prospectively recruited into our study. Each patient underwent a 3D MRI of both the injured and uninjured knees before surgery. The contralateral (uninjured) knee scan was used to define the patient’s native footprint. Patients then underwent ACL reconstruction with hamstring autograft by one of four experienced fellowship-trained sports orthopedic surgeons. The injured knee was reimaged after surgery. The location and percent overlap of the reconstructed femoral footprint was compared to the patient’s native footprint.Results:The center of the native ACL femoral footprint was a mean of 16.4 +/- 4.6 mm distal and 5.3 +/- 2.9 mm anterior to the apex of the deep cartilage. The position of the reconstructed graft was significantly different, with mean distance of 10.4 +/- 2.7 mm distal (P < 0.0001) and 7.7 +/- 3.1 mm anterior (P = 0.001). The mean distance between the center of the graft and the center of the native ACL femoral footprint (error distance) was 5.7 +/- 3.6 mm. Comparing error distances amongst the four surgeons demonstrated no significant difference using the Kruskal-Wallis one-way ANOVA (P = 0.78). On average, 21% of the graft was within the native ACL femoral footprint. Of the 41 patients, 16 (39%) had the graft placed entirely outside the native ACL footprint.Conclusion:Despite contemporary techniques and a concerted effort to perform anatomic ACL reconstructions by four experienced sports orthopedic surgeons, the position of the femoral footprint was significantly different between the native and reconstructed ligaments. Furthermore, each of the four surgeons uses a different technique but all had comparable errors in their tunnel placements. In order to achieve a truly anatomic reconstruction, surgeons may consider using a pre-operative 3D MRI, which enables excellent visualization of the ACL’s native anatomy and could potentially be used as a roadmap to guide anatomic tunnel placement.

Accurate Positioning of Femoral and Tibial Tunnels in Single Bundle Anterior Cruciate Ligament Reconstruction Using the Indigenously Made Bernard and Hurtle Grid on a Transparency Sheet and C-arm

Many factors determine the outcome of the anterior cruciate ligament reconstruction surgery. The single most important factor, also well within the control of a surgeon, is tunnel placement. It is difficult to accurately determine the center of the anterior cruciate ligament foot print, and many a times it is also difficult to accurately define the intercondylar and bifurcate ridge. This makes determination of the accurate entry point of the guidewire difficult. We have printed our indigenously formed grid (equidistant boxes) on an old-fashioned transparency sheet. We use a fluoroscopy (C-arm) shot intraoperatively in the lateral position and superimpose this sheet to determine the position of the guidewire by calculating the percentage of boxes. We aim at 27.7% in proximal to distal and 37.5% in anterior to posterior on the femur side and 45% in front to back and medial to lateral on the tibial side. C-arm is freely available, but the inbuilt grid facility may be available in only the higher version of C-arms. Our indigenously designed grid can be easily used across the globe with ease to achieve accuracy in tunnel placement without violating anatomy and without any extra cost.

Does anatomic single-bundle ACL reconstruction using hamstring autograft produce anterolateral meniscal root tearing?

BackgroundTo determine if tibial tunnel reaming during anatomic single-bundle anterior cruciate ligament (ACL) reconstruction using hamstring autograft can result in anterolateral meniscal root injury, as diagnosed by magnetic resonance imaging (MRI).MethodsA case series of 104 primary anatomic single-bundle ACL reconstructions using hamstring autograft was retrospectively reviewed. Pre- and post-operative (>1 year) MRIs were radiologically evaluated for each patient, with a lateral meniscus extrusion > 3 mm at the level of the medial collateral ligament midportion on a coronal MRI, to establish anterolateral meniscal root injury.ResultsNo patients presented radiological findings of anterolateral meniscal root injury in this case series.ConclusionsExamining a single-bundle ACL reconstruction technique using hamstring autograft that considered tibial tunnel positioning in the center of the tibial footprint, this case series found no evidence of anterolateral meniscal root injury in patient MRIs, even more than 1-year post-operation.

Quantitative MRI Evaluation of Tunnel placement in ACL Reconstruction

Introduction:Positioning of the graft ACL in the native footprint center is important to replicate the anatomy and function of the ACL for each individual patient. It is known that incorrect bone tunnel placement for the reconstructed ligament is a contributor to poor clinical outcomes postoperatively. Currently the success of tunnel placement is determined by training and experience of the treating surgeon and there is no universally accepted quantifiable and objective method to evaluate the execution of these decisions. The goal of this project was to develop a quantitative routine assessment to assist pre-surgical planning and also evaluate the execution of femoral and tibial bone tunnel placement in ACL reconstructed knees.Methods:The study recruited failed primary ACL reconstructed patients (N=25) who consented to undergo revision ACL reconstruction to establish the placement of the graft ACL tunnel apertures in the femur and tibia. Prior to surgery each participant underwent high resolution 3 T MRI of their injured knee and 3D models were generated through segmentation of soft and hard tissue knee structures. During surgery previous graft tunnels and prominent reference landmarks visible on MRI and arthroscopically were registered using intraoperative navigation to act as the reference standard. The placement of the tunnel apertures in the femur and tibia were measured in all three planes using a novel measurement method.Results:Preliminary result show that the measurement method can assess the placement of tunnel apertures in the femur and tibia within 0.1 – 1.0 mm of the intraoperative data, using reference landmarks identifiable in MRI and arthroscopically. Additionally, the area of the tunnel aperture, bone tunnel volume can be evaluated. Reliability and validation of the novel method is ongoing using medical imaging and intraoperative navigation to register the placement of bone tunnels in revision ACL reconstruction patients.Conclusions:Correct placement of graft ACL bone tunnels inside the native ACL footprint is critical to the outcome of ACL reconstruction. Development of an accurate reproducible method for assessment of tunnel placement relative to the anatomical footprint should provide a simple method for objectively assessing ACL reconstructions. Preliminary results of this routine assessment suggests that graft tunnel placement can be objectively assessed to assist clinicians to evaluate and improve ACL reconstruction technique and evaluation of ACL reconstruction outcomes.

Finite element analysis for investigation of the etiology of osteochondritis dissecans in medial femoral condyle

Purpose: Osteochondritis dissecans (OCD) was reported by Franz Köenig in 1888. So far, repetitive microtrauma is a favorable and the most accepted etiology because patients with OCD are usually involved in high athletic activity and the increase of the patient population associated with increasing sports participation. Recently we introduced a unique anatomic feature of the femoral footprint of posterior cruciate ligament (PCL) in the patients with MFC OCD lesions. In the previous study, it was demonstrated that the femoral footprint of the PCL in patients with MFC OCD was located significantly distal position compared to the patients with non-OCD lesions. However, the mechanism predisposing to lesions due to this anatomic factor still remains unsolved. The purpose of this study was to investigate the alteration of in situ stress on the MFC due to distalized femoral footprint of PCL at knee flexion using finite element (FE) model. Methods: This study was approved by the Ethical Committee of Hiroshima University (Approval number: E-14). Establishment of three-dimensional models: The CT images of the left knee joint, taken at full extension and 110° flexion without an applied load on the quadriceps or hamstrings, of a 11-year old boy were used for this analysis. From these images, we established the three-dimensional (3D) models in each position. Finite element model: These 3D images were imported into the Abaqus software (ver. 6.11-1, Dassault Systemes, Paris, France) for processing the FE model in each position. The element size was 1.0 mm each and there were 307,027 elements with 118,884 nodes. The thickness of the cortical bone was set as 2.5 mm based on the CT data and triangular prism elements (C3D6). This cortical bone area was divided into 4 layers from the surface to the border of cancellous bone. The cancellous bone was filled with tetrahedron elements (C3D4). Material property of the PCL and conditioning of femoral footprint: The PCL footprints at femur and tibia were decided from the MR images. We illustrated the PCL as a single bundle ligament. The diameter of femoral and tibial footprints of the PCL was set as 7 mm from the MR images. The center of each footprint was connected by single non-linear cable element representing as the PCL ligament. The elastic module of the PCL was set as 131.5 MPa. The stress-strain relationship of nonlinear ligament elements was described following previous report. Boundary and loading condition: We fixed the femur and the tibia was forced to 110°-flexed position of the knee. In this motion, the stress alternation upon femur due to distalization of femoral footprint of the PCL was evaluated. For distalization of the femoral footprint of the PCL, we made a 50% offset of the center, i.e. 3.5 mm distalization of center of footprint along the Z-axis, as a distalized model. Results: From the distalization of the femoral footprint of the PCL, the distance from the center of femoral footprint to the tibial side increased from 30.99 mm to 33.63 mm in 110°-flexed position, the difference was 2.64 mm. The stress at femoral footprint was similar in pre and post-distalization, 3.0 MPa each. And this stress was observed from the cortical to cancellous bone layers and also this stress was similar in pre- and post-distalization models, 1.5 and 1.6 MPa, respectively. However, its distribution was altered in post-distalization model. The layer in cortical bone was evaluated in each layer and we found slightly higher stress existed in all layers in the distalized model, this difference was 0.25 MPa though (Figure 1). Conclusions: In this study, we demonstrated that the distalization of femoral footprint of the PCL alter stress distribution in MFC from FE analysis. And interestingly, this stress distribution was exactly matched with MFC OCD lesion that we frequently observe fissure, fibrillation, and detachment of subchondral bone at arthroscopy. To our knowledge, this is the first report to unveil the etiology of OCD using the mathematical method.

Effects of ACL graft placement on in vivo knee function and cartilage thickness distributions.

Injuries to the anterior cruciate ligament (ACL) frequently lead to early-onset osteoarthritis. Despite advancement in surgical techniques, ACL reconstruction has a limited ability to prevent these degenerative changes. While previous studies have investigated knee function after ACL reconstruction, in vivo investigations of the effects of graft placement on in vivo joint function and cartilage health are limited. This review presents a series of studies that used novel imaging and 3D modeling techniques to determine the in vivo placement of the ACL graft on the femur using two different ACL reconstruction techniques. These techniques resulted in two distinct graft placement groups: one where the ACL was placed anatomically near the center of the native ACL footprint and another where the graft was placed anteroproximally on the femur, centered outside the ACL footprint. We quantified the effects of graft placement on graft deformation during in vivo loading and how these variables affected knee motion. Finally, we quantified whether femoral placement of the graft affected cartilage thickness. Our results demonstrate that achieving anatomic graft placement on the femur is critical to restoring native ACL function and normal knee kinematics. Knees with grafts that more closely restored normal ACL function, and thus knee motion, experienced less focal cartilage thinning than did those that experienced abnormal knee motion. These results suggest that achieving anatomic graft placement is a critical factor in restoring normal knee motion and potentially slowing the development of degenerative changes after ACL reconstruction. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1160-1170, 2017.

Quantitative radiographic assessment of the anatomic attachment sites of the anterior and posterior complexes of the proximal tibiofibular joint.

Quantitative guidelines for radiographic identification of the anterior and posterior ligaments of the proximal tibiofibular joint have not been well defined. The purpose of this study was to provide reproducible, quantitative descriptions of radiographic landmarks identifying the anterior and posterior ligament complexes of the proximal tibiofibular joint. It was hypothesized that consistent quantitative data regarding the radiographic location of the anterior and posterior proximal tibiofibular joint ligament complexes could be identified. The footprint centers of the individual ligament bundles of the anterior and posterior complexes of the proximal tibiofibular joint were labeled with radio-opaque markers in ten non-paired, fresh-frozen cadaveric knee specimens. Anteroposterior (AP) and lateral radiographs of the proximal tibiofibular joint were obtained, and distances between the markers and pertinent radiographic landmarks were recorded. On AP radiographs, the tibial span of the anterior complex was 12.8 ± 3.9mm and started at a median of 11.4mm distal to the tibial plateau; the fibular span was 11.6 ± 6.8mm and started at a median of 5.1mm from the apex of the fibular styloid. The tibial span of the posterior complex was 11.7 ± 8.4mm and began at a median of 12.1mm distal to the tibial plateau; the fibular span was 11.8 ± 7.9mm and began at a median of 3.1mm distal to the apex of the fibular styloid. Values were similar for lateral radiographs. The attachment locations of the proximal tibiofibular anterior and posterior complexes could be quantitatively correlated to reliable osseous landmarks and radiographic lines. This information will allow for consistent radiographic assessments of proper tunnel placement intraoperatively and postoperatively during anatomic reconstructions of the proximal tibiofibular joint.

Proximity of Lateral Critical Structures to the All-Epiphyseal Outside-In Femoral Tunnels in Pediatric Anterior Cruciate Ligament Reconstruction

To describe the proximity of the lateral critical structures (peroneal nerve [PN], popliteus tendon [PT], lateral collateral ligament [LCL], and articular cartilage [AC]) to the femoral tunnel for outside-in all-epiphyseal anterior cruciate ligament (ACL) reconstruction in reference to knee flexion angle. All-epiphyseal ACL reconstructions were performed in 12 human cadaveric knees using arthroscopy and outside-in drilling for anatomic femoral tunnel placement that was ensured by identifying the center of the total ACL footprint. Fluoroscopy was used to confirm tunnel position and reconstructions were performed with quadrupled semitendinosus and gracilis autograft with Xtendobutton (Smith & Nephew, Andover, MA) fixation on the femoral side. After reconstruction, the lateral side of the knee was dissected and the LCL, PT, distal and posterior AC, and the PN were identified. The distances of these structures from the center of the exiting femoral tunnel were then measured using a digital caliper at 0°, 30°, 60°, 90°, and 120° of knee flexion. Any gross damage to these structures caused by the femoral drilling was also noted. Data were compiled and the mean and standard deviations (SD) of the distances from the pin to the structures of interest were calculated. The normality of the data at each flexion angle was assessed using Shapiro-Wilk tests (P > .05), and the relationship between flexion angle and average distance was evaluated using repeated measures analysis of variance (P < .05). Any significant relationships were then evaluated using paired t-tests (P < .05) with a Benjamini-Hochberg adjustment for each possible pair of flexion angles. Averages, SD, and P values are reported. A post hoc power analysis was performed. The violation of the LCL was noted in 3 specimens and that of the PT in 1 specimen as a result of femoral tunnel drilling at flexion angles ranging from 90° to 120°. The distance between the PT and the femoral tunnel also decreased significantly (P < .001) with knee flexion with average distances to the center of 8.07mm at 0°, 7.75mm at 30°, 6.33mm at 60°, 4.12mm at 90°, and 1.89mm at 120°. The mean ± SD for distances from the femoral tunnel to the center of the PT at 0° was 8.07 ± 7.15, at 30° 7.75 ± 6.66, at 60° 6.33 ± 6.79, at 90° 4.12 ± 5.71, and at 120° 1.89 ± 5.56. As the knee was progressively flexed, the distance between the LCL and the femoral tunnel decreased significantly (P < .001) with an average distance of 6.52mm at 0°, 6.26mm at 30°, 4.23mm at 60°, 2.38mm at 90°, and 0.4mm at 120°. The mean ± SD for distances from the femoral tunnel to the center of the LCL at 0° was 6.52 ± 5.93, at 30° 6.26 ± 7.32, at 60° 4.23 ± 7.82, 90° 2.38 ± 7.31, and at 120° 0.4 ± 7.01. The PN was remote from the femoral tunnel at all flexion angles with a mean distance of 42.83 to 59.22mm. The PN to guide pin distance increased significantly with progressive knee flexion (P<.001). The AC was not damaged in all specimens. The LCL and PT are at significant risk during percutaneous femoral drilling for all-epiphyseal anatomic ACL reconstruction using an outside-in technique. This risk was maximized at 120° flexion and minimized in full extension. These findings suggest that the optimal position for femoral drilling in all-epiphyseal ACL reconstruction is full or near-full extension of the knee that can be accomplished by placing the knee in 30° of flexion (after using fluoroscopic guidance to pass the guide pin past the lateral critical structures) to visualize the footprint of the ACL. Information garnered from this study may help clinicians better understand the risk to the lateral critical structures when an outside-in femoral tunnel is not drilled in the appropriate degree of knee flexion.

3D Computed Tomography Evaluation of Morphological Changes in the Femoral Tunnel After Medial Patellofemoral Ligament Reconstruction With Hamstring Tendon Graft for Recurrent Patellar Dislocation

Background: Reconstruction of the medial patellofemoral ligament (MPFL) for recurrent lateral patellar dislocation is gaining popularity. However, the morphological changes in the femoral tunnel after MPFL reconstruction are still not fully documented. Purpose: This study used 3-dimensional (3D) computed tomography to evaluate morphological changes in the femoral tunnel after MPFL reconstruction with hamstring tendon graft to investigate factors affecting the phenomenon and to elucidate whether it is associated with clinical outcomes. Study Design: Case series; Level of evidence, 4. Methods: Twenty-three patients with recurrent patellar dislocation were prospectively enrolled in this study. The patients included 6 males and 17 females with a mean age of 24 years (range, 14-53). The MPFL was reconstructed by creating 2 patellar bone sockets and 1 femoral bone socket anatomically under X-ray control, and the semitendinosus autograft was fixed with cortical suspension devices. Computed tomography scans obtained 3 weeks and 1 year after surgery were reconstructed into 3D constructs with a volume analyzer. Cross-sectional areas (CSAs) of the aperture and inside the femoral tunnel were compared between the 2 time points. Likewise, the location of tunnel walls and center of the femoral tunnel footprint were evaluated. Relationships were assessed between femoral tunnel morphological changes and potential risk factors—such as age, body mass index, sex, femoral tunnel positioning, patellar height, sulcus angle, congruence angle, lateral tilt angle, degree of trochlear dysplasia, lateral deviation of the tibial tubercle, and Kujala score. Results: No patient reported recurrence of patellar dislocation during the follow-up period. The CSA of the femoral tunnel aperture enlarged by 41.1% ± 34.7% (P < .01). The center, anterior border, and proximal border of the femoral tunnel significantly shifted in the anterior direction (P < .01). The distal border significantly shifted in both anterior and distal directions (P < .01). Patella alta was associated with distal migration of the tunnel center (P < .05). Morphological changes were not associated with other risk factors or Kujala score. Conclusion: The CSA of the femoral tunnel aperture enlarged, and the tunnel aperture migrated anteriorly with time after MPFL reconstruction. Risk factors for patellar dislocation other than patella alta did not influence morphological changes of the femoral tunnel.

Anatomıc femoral tunnel drilling in acl reconstruction without using of an accessory medial portal and evaluation of femoral tunnel positioning using 3-d computed tomography

Background and Purpose:Characterization of the insertion site anatomy in anterior cruciate ligament reconstruction has recently received increased attention in the literature, coinciding with a growing interest in anatomic reconstruction. The purpose of this study is to report a modified novel transportal technique to approach the center of anatomical femoral footprint in anterior cruciate ligament (ACL) reconstruction and to investigate the accurate femoral tunnel position with 3-dimensional computed tomography (3D-CT). Materials-Methods: We evaluated 11 patients who underwent primary ACL reconstruction using a modified transportal technique to approach the center of anatomical femoral footprint in single bundle ACL reconstruction with hamstring autograft. Their femoral tunnel positions were investigated with 3D-CT postoperatively according to the quadrant method by three orthopedic surgeons.Results:According to the quadrant method with 3D-CT, the femoral tunnel was measured at a mean of 33,49% ± 5,59% from the proximal condylar surface (parallel to the Blumensaat line) and 32,93% ± 3,82% from the notch roof (perpendicular to the Blumensaat line) with good interobserver (intraclass correlation coefficients [ICC], 0,991and 0,858, respectively with 0,975 – 0,997%95 CI) and intraobserver reliability (ICC, 0.875 and 0.893, respectively with 0,663 – 0,956%95 CI).Conclusions:Our modified transportal technique is anticipated to provide anatomical placement of the femoral tunnel during ACL reconstruction than the former traditional transtibial techniques. This technique is reproducible and also easier to perform than classic transportal technique does not need extra arthroscopic portal.3D

A Validation Study of a Novel 3-Dimensional MRI Modeling Technique to Identify the Anatomic Insertions of the Anterior Cruciate Ligament.

Background:Anatomic single bundle anterior cruciate ligament (ACL) reconstruction is the current gold standard in ACL reconstructive surgery. However, placement of femoral and tibial tunnels at the anatomic center of the ACL insertion sites can be difficult intraoperatively. We developed a “virtual arthroscopy” program that allows users to identify ACL insertions on preoperative knee magnetic resonance images (MRIs) and generates a 3-dimensional (3D) bone model that matches the arthroscopic view to help guide intraoperative tunnel placement.Purpose:To test the validity of the ACL insertion sites identified using our 3D modeling program and to determine the accuracy of arthroscopic ACL reconstruction guided by our “virtual arthroscopic” model.Study Design:Descriptive laboratory study.Methods:Sixteen cadaveric knees were prescanned using routine MRI sequences. A trained, blinded observer then identified the center of the ACL insertions using our program. Eight knees were dissected, and the centers of the ACL footprints were marked with a screw. In the remaining 8 knees, arthroscopic ACL tunnels were drilled into the center of the ACL footprints based on landmarks identified using our virtual arthroscopic model. Postprocedural MRI was performed on all 16 knees. The 3D distance between pre- and postoperative 3D centers of the ACL were calculated by 2 trained, blinded observers and a musculoskeletal radiologist.Results:With 2 outliers removed, the postoperative femoral and tibial tunnel placements in the open specimens differed by 2.5 ± 0.9 mm and 2.9 ± 0.7 mm from preoperative centers identified on MRI. Postoperative femoral and tibial tunnel centers in the arthroscopic specimens differed by 3.2 ± 0.9 mm and 2.9 ± 0.7 mm, respectively.Conclusion:Our results show that MRI-based 3D localization of the ACL and our virtual arthroscopic modeling program is feasible and does not show a statistically significant difference to an open arthrotomy approach. However, additional refinements will be required to improve the accuracy and consistency of our model to make this an effective tool for surgeons performing anatomic single-bundle ACL reconstructions.Clinical Relevance:Arthroscopic anatomic single-bundle ACL reconstruction is the current gold standard for ACL reconstruction; however, the center of the ACL footprint can be difficult to identify arthroscopically. Our novel modeling can improve the identification of this important landmark intraoperatively and decrease the risk of graft malposition and subsequent graft failure.

The Anatomic Centers of the Femoral and Tibial Insertions of the Anterior Cruciate Ligament: A Systematic Review of Imaging and Cadaveric Studies Reporting Normal Center Locations

Background: The anterior cruciate ligament (ACL) is regularly reconstructed if knee joint function is impaired. Anatomic graft tunnel placement, often assessed with varying measurement methods, in the femur and tibia is considered important for an optimal clinical outcome. A consensus on the exact location of the femoral and tibial footprint centers is lacking. Purpose: To systematically review the literature regarding anatomic centers of the femoral and tibial ACL footprints and assess the mean, median, and percentiles of normal centers. Study Design: Systematic review. Methods: A systematic literature search was performed in the PubMed/Medline database in November 2015. Search terms were the following: “ACL” and “insertion anatomy” or “anatomic footprint” or “radiographic landmarks” or “quadrant methods” or “tunnel placement” or “cadaveric femoral” or “cadaveric tibial.” English-language articles that reported the location of the ACL footprint according to the Bernard and Hertel grid in the femur and the Stäubli and Rauschning method in the tibia were included. Weighted means, weighted medians, and weighted 5th and 95th percentiles were calculated. Results: The initial search yielded 1393 articles. After applying the inclusion and exclusion criteria, 16 studies with measurements on cadaveric specimens or a healthy population were reviewed. The weighted mean of the femoral insertion center based on measurements in 218 knees was 29% in the deep-shallow (DS) direction and 35% in the high-low (HL) direction. The weighted median was 26% for DS and 34% for HL. The weighted 5th and 95th percentiles for DS were 24% and 37%, respectively, and for HL were 28% and 43%, respectively. The weighted mean of the tibial insertion center in the anterior-posterior direction based on measurements in 300 knees was 42%, and the weighted median was 44%; the 5th and 95th percentiles were 39% and 46%, respectively. Conclusion: Our results show slight differences between the weighted means and medians in the femoral and tibial insertion centers. We recommend the use of the 5th and 95th percentiles when considering postoperative placement to be “in or out of the anatomic range.”