Evaluation of the Angle Between the Long Axis of the Femoral Anterior Cruciate Ligament Footprint and Bony Morphology of the Knee: A Cadaveric Descriptive Study.

Purpose: There have been numerous studies of the anterior cruciate ligament (ACL) anatomy, but few have focused on the long axis angle of the femoral ACL footprint. This study investigated the angle between the long axis of the femoral ACL footprint and the bony morphology of the knee. Methods: This study is a cadaveric descriptive study. Thirty non-paired formalin-fixed knees of Japanese cadavers were used. Anteromedial (AM) and posterolateral (PL) bundles were identified according to the tension pattern differences during the complete range of motion of the knee. In the ACL femoral footprint, there is a fold between the mid-substance insertion site and fan-like extension fibers. After identifying AM and PL bundles of mid-substance fibers, the mid-substance and fan-like extension fibers were divided into those bundles and stained. We defined the line passing through the center of the AM and PL bundles as the long axis of the ACL. The center points of each of the four areas and the angle between the long axis of the ACL and the bony morphology of the knee were calculated using Image J software. Results: The mean angle between the axis of the femoral shaft and the long axis of the ACL mid-substance insertion was 28.8 ± 12.2 degrees. The mean angle between the Blumensaat line and the long axis of the mid-substance was 54.2 ± 13.5 degrees. Conclusion: The mean angle between the axis of the femoral shaft and the long axis of the femoral ACL footprint was approximately 29 degrees. There is a wide variation in the long axis of the femoral ACL footprint. To achieve better clinical results through a more anatomically accurate reconstruction, it can be beneficial to replicate the ACL femoral footprint along its native long axis.

Femoral Tunnel Position in Anatomical Double-bundle ACL Reconstruction is not Affected by Blumensaat's Line Morphology.

The aim of this study was to reveal the influence of the morphological variations of the Blumensaat's line on anteromedial (AM) and posterolateral (PL) femoral tunnel position in anatomical double-bundle anterior cruciate ligament (ACL) reconstruction.Fifty-three subjects undergoing anatomical double-bundle ACL reconstruction were included (29 female, 24 male; median age 27.4 years; range: 14-50 years). Using an inside-out transportal technique, the PL tunnel position was made on a line drawn vertically from the bottommost point of the lateral condyle at 90 degrees of knee flexion, spanning a distance of 5 to 8 mm, to the edge of the joint cartilage. AM tunnel position was made 2 mm distal to the PL tunnel position. Following Iriuchishima's classification, the morphology of the Blumensaat's line was classified into straight and hill (large and small) types. Femoral tunnel position was determined using the quadrant method. A Mann-Whitney U test was performed to compare straight and hill type knees according to AM and PL femoral tunnel position.There were 18 straight and 35 hill type knees (13 small and 22 large hill). AM and PL femoral tunnel position in straight type knees were 21.7 ± 7.0 and 33.6 ± 10.5% in the shallow-deep direction, and 42.1 ± 11.1 and 72.1 ± 8.5% in the high-low direction, respectively. In hill type knees, AM and PL femoral tunnel position were 21.3 ± 5.8 and 36.9 ± 7.1% in the shallow-deep direction, and 44.6 ± 10.7 and 72.1 ± 9.7% in the high-low direction, respectively. No significant difference in AM or PL femoral tunnel position was detected between straight and hill type knees.AM and PL femoral tunnel position in anatomical double-bundle ACL reconstruction was not affected by the morphological variations of the Blumensaat's line. Surgeons do not need to consider Blumensaat's line morphology if AM and PL femoral tunnel position is targeted at the bottommost point of the lateral condyle. This was a level of evidence III study.

Bony mallet toe of the hallux treated with screws: a case report.

Traumatic avulsion fracture of the distal phalanx of the hallux, known as the bony mallet toe of the hallux, is rare, and there is no consensus regarding its treatment. Few reports of treatment methods exist, such as nonsurgical treatment using a splint, Kirschner wires, and suture anchors, but there are no reports of screw fixation. We describe the case of a 54-year-old man with a bony mallet toe of the hallux treated with screws and augmented with strong sutures. The interphalangeal joint of the hallux was fixed with a Kirschner wire for 4 weeks after surgery, and weight bearing was allowed on the hallux 5 weeks postoperatively. A total of 20 months after the surgery, the patient had no symptoms or complications. Because of screw fixation and augmentation with strong sutures, fixation strength increased. We showed the feasibility of this new technique for treating an uncommon bony mallet toe of the hallux.

Femoral Tunnel Length in Anatomical Double-Bundle Anterior Cruciate Ligament Reconstruction Is Correlated with Body Size and Knee Morphology.

The purpose of this study was to reveal the correlation between anteromedial (AM) and posterolateral (PL) femoral tunnel lengths in anatomical double-bundle anterior cruciate ligament (ACL) reconstruction and body size and knee morphology. Thirty-four subjects undergoing anatomical double-bundle ACL reconstruction were included in this study. Preoperative body size (height, body weight, and body mass index) was measured. Using preoperative magnetic resonance imaging (MRI), quadriceps tendon thickness and the whole anterior-posterior length of the knee were measured. Using postoperative computed tomography (CT), axial and sagittal views of the femoral condyle were evaluated. The correlation between measured intraoperative AM and PL femoral tunnel lengths, and body size and knee morphology using preoperative MRI and postoperative CT parameters was statistically analyzed. Both AM and PL femoral tunnel lengths were significantly correlated with height, body weight, posterior condylar length, and Blumensaat's line length. These results suggest that the femoral ACL tunnel length created using a transportal technique can be estimated preoperatively by measuring the subject's body size and/or the knee morphology using MRI or CT. For clinical relevance, surgeons should be careful to create femoral tunnel of sufficient length when using a transportal technique, especially in knees of subjects with smaller body size and knee morphology. Level of evidence is III.

Size Comparison of the Cadaveric Anterior Cruciate Ligament Midsubstance Cross-Sectional Area and the Cross-Sectional Area of Semitendinosus Double-Bundle Anterior Cruciate Ligament Reconstruction Autografts in Surgery.

The purpose of this study was to compare the cadaveric midsubstance cross-sectional anterior cruciate ligament (ACL) area and the cross-sectional semitendinosus (ST) double-bundle ACL autograft area in surgery. Thirty-nine nonpaired formalin-fixed cadaveric knees and 39 subjects undergoing ST double-bundle ACL reconstruction were included in this study. After soft tissue resection, cadaveric knees were flexed at 90 degrees, and the tangential line of the femoral posterior condyles was marked and sliced on the ACL midsubstance. The cross-sectional ACL area was measured using Image J software. In the patients undergoing ACL surgery, the harvested ST was cut and divided into anteromedial (AM) bundle and posterolateral (PL) bundle. Each graft edge diameter was measured by a sizing tube, and the cross-sectional graft area was calculated: (AM diameter/2)2 × 3.14 + (PL diameter/2)2 × 3.14. Statistical analysis was performed for the comparison of the cross-sectional area between the cadaveric ACL midsubstance and the ST double-bundle ACL autografts. The cadaveric midsubstance cross-sectional ACL area was 49.0 ± 16.3 mm2. The cross-sectional ST double-bundle autografts area was 52.8 ± 7.6 mm2. The ST double-bundle autograft area showed no significant difference when compared with the midsubstance cross-sectional ACL area. ST double-bundle autografts were shown to be capable of reproducing the midsubstance cross-sectional ACL area.

The location of the femoral ACL footprint center is different depending on the Blumensaat's line morphology.

PURPOSE: The purpose of this study was to evaluate the difference in the center point of the femoral ACL footprint according to the morphological variations of the Blumensaat's line. METHODS: Fifty-nine non-paired human cadaver knees were used. The ACL was cut in the middle, and the femoral bone was cut at the most proximal point of the femoral notch. Digital images were evaluated using the Image J software. The periphery of the femoral ACL footprint was outlined and the center point was measured automatically. Following Iriuchishima's classification, the morphology of the Blumensaat's line was classified into straight and hill types (small and large hill types). The center of the femoral ACL footprint and hilltop placement were evaluated using the quadrant method. A quadrant grid was placed uniformly, irregardless of hill existence, and not including the articular cartilage. A correlation analysis was performed between the center point of the femoral ACL footprint and hilltop placement. RESULTS: The straight type consisted of 19 knees, and the hill type 40 knees (small hill type 13 knees and large hill type 27 knees). The center of the femoral ACL footprint (shallow-deep/high-low) in the straight and hill type knees was 33.7/47.6%, and 37.2/50.3%, respectively. In the hill type, the ACL footprint center was significantly more shallow when compared to the straight type. Significant correlation was observed between the center point of the femoral ACL footprint and hilltop placement of the Blumensaat's line. CONCLUSION: The center point of the femoral ACL footprint was significantly more shallow in the hill type knees when compared to the straight type. For clinical relevance, considering that the location of the femoral ACL footprint center is different depending on the Blumensaat's line morphology, to perform accurate ACL reconstruction, femoral ACL tunnel placement should be made based on Blumensaat's line morphological variations.

Morphology of the resident's ridge, and the cortical thickness in the lateral wall of the femoral intercondylar notch correlate with the morphological variations of the Blumensaat's line.

PURPOSE: The purpose of this study was to reveal the morphological correlation between the lateral wall of femoral intercondylar notch and the Blumensaat's line. METHODS: Forty-one non-paired human cadaveric knees were included in this study (23 female, 18 male: median age 83). Knees were resected, and 3 dimensional computed tomography (3D-CT) was performed. In the axial CT image, bony protrusion (resident's ridge) and cortical thickness in the lateral wall of the femoral intercondylar notch were detected. The length between the top of the ridge, or the most anterior, middle, and most posterior border of cortical thickness and posterior femoral condylar line was measured. Following Iriuchishima's classification, the morphology of the Blumensaat's line was classified into straight and hill types (small and large hill types). In the hill types, the length between the hilltop and the posterior border of the Blumensaat's line or the posterior border of the femoral condyle was evaluated. Statistical correlation was calculated between the top of the ridge location, cortical thickness location in the notch, and hilltop location. RESULTS: There were 7 straight type knees and 34 hill type knees (9 small hill type knees and 25 large hill type knees). Only the hill types of knees were evaluated. The top of the ridge, anterior margin, middle, and posterior border of cortical thickness in the lateral wall of the femoral intercondylar notch existed at 61.8 ± 4.6%, 58.3 ± 12.3%, 42.1 ± 7.9%, and 25.5 ± 5.4% from the posterior condylar line, respectively. The hilltop existed at 24.9 ± 5.9% and 30.7 ± 5.0%, from the posterior border of the Blumensaat's line and from the posterior border of the femoral condyle, respectively. Significant correlation was observed between resident's ridge top, cortical thickness location and hilltop location. CONCLUSION: In all cadaveric knees, cortical thickness was detected in the lateral wall of the femoral intercondylar notch. The resident's ridge and cortical thickness location had significant correlation with the hill location in the Blumensaat's line, indicating a continuation of the cortical bone from the posterior cortex of the femoral shaft via the hilltop of the Blumensaat's line to the cortical thickness in the lateral wall of the femoral intercondylar notch. For clinical relevance, hilltop location in the Blumensaat's line is a new bony landmark in anterior cruciate ligament surgery.

Correlation between the mid-substance cross-sectional anterior cruciate ligament size and the knee osseous morphology.

INTRODUCTION: One of the final goals of anatomical anterior cruciate ligament (ACL) reconstruction is the restoration of native anatomy. It is essential to obtain more accurate predictors of mid-substance ACL size before surgery. However, to the best of our knowledge, no study has reported correlation between the mid-substance cross-sectional ACL size and the knee osseous morphology. The purpose of this study was to reveal correlation between the mid-substance cross-sectional ACL size and the knee osseous morphology. MATERIALS AND METHODS: We used 39 non-paired formalin fixed Japanese cadaveric knees. All surrounding muscles, ligaments and soft tissues in the knee were resected. After soft tissue resection, the knee was flexed at 90°, and a tangential plane of the femoral posterior condyles was marked and cut the ACL. Femoral ACL footprint size, Blumensaat's line length, lateral wall of the femoral intercondylar notch size, lateral wall of the femoral intercondylar notch height, tibial ACL footprint size, tibia plateau size, the whole anterior-posterior (AP) length, the medial and the lateral AP length of the tibia plateau, and the medial-lateral (ML) length of the tibia plateau were measured. The Pearson's product movement correlation was calculated to reveal correlation between the mid-substance cross-sectional ACL size and the measured parameters of the knee osseous morphology. RESULTS: The measured mid-substance cross-sectional ACL size was 49.9 ± 16.3 mm2. The tibial ACL footprint size, the tibia plateau size, the whole AP length of the tibia plateau, the lateral AP length of the tibia plateau and the ML length of the tibia plateau were significantly correlated with the mid-substance cross-sectional ACL size. CONCLUSIONS: For clinical relevance, some tibial sides of the knee osseous morphology were significantly correlated with the mid-substance cross-sectional ACL size. It might be possible to predict the mid-substance ACL size measuring these parameters.

Measurement of the Whole and Midsubstance Femoral Insertion of the Anterior Cruciate Ligament: The Comparison with the Elliptically Calculated Femoral Anterior Cruciate Ligament Footprint Area.

PURPOSE: The purpose of this study was to measure the detailed morphology of the femoral anterior cruciate ligament (ACL) footprint. The correlation and the comparison between the measured area and the area which mathematically calculated as elliptical were also evaluated. MATERIALS AND METHODS: Thirty nine nonpaired human cadaver knees were used. The ACL was cut in the middle, and the femoral bone was cut at the most proximal point of the femoral notch. The ACL was carefully dissected, and the periphery of the ACL insertion site was outlined on both the whole footprint and the midsubstance insertion. Lateral view of the femoral condyle was photographed with a digital camera, and the images were downloaded to a personal computer. The area, length, and width of the femoral ACL footprint were measured with Image J software (National Institution of Health). Using the length and width of the femoral ACL footprint, the elliptical area was calculated as 0.25 π (length × width). Statistical analysis was performed to reveal the correlation and the comparison of the measured and elliptically calculated area. RESULTS: The sizes of the whole and midsubstance femoral ACL footprints were 127.6 ± 41.7 mm2 and 61 ± 20.2 mm2, respectively. The sizes of the elliptically calculated whole and midsubstance femoral ACL footprints were 113.9 ± 4.5 mm2 and 58.4 ± 3 mm2, respectively. Significant difference was observed between the measured and the elliptically calculated area. In the midsubstance insertion, significant correlation was observed between the measured and the elliptically calculated area (Pearson's correlation coefficient = 0.603, P = 0.001). However, no correlation was observed in the whole ACL insertion area. CONCLUSION: The morphology of the femoral ACL insertion resembles an elliptical shape. However, due to the wide variation in morphology, the femoral ACL insertion cannot be considered mathematically elliptical.

The correlation between the femoral anterior cruciate ligament footprint area and the morphology of the distal femur: three-dimensional CT evaluation in cadaveric knees.

BACKGROUNDS: "Anatomical" anterior cruciate ligament (ACL) reconstruction is defined as the functional restoration of the ACL to its native dimensions. It is essential to obtain more accurate predictors of ACL size before surgery. The purpose of this study was to investigate the correlation between the native femoral ACL footprint size and the morphology of the distal femur using three-dimensional CT (3D-CT). METHODS: Thirty non-paired Japanese human cadaver knees were used. All soft tissues around the knee were resected except the ACL. For the evaluation of femoral condyle morphology, trans-epicondylar length (TEL), notch outlet length, axial notch area, and notch width index were measured using 3D-CT. The ACL was cut in the middle, and the femoral bone was cut at the most proximal point of the femoral notch. The ACL was carefully dissected, and the boundaries of the ACL insertion site were outlined on the femoral side. An accurate lateral view of the femoral condyle was photographed with a digital camera. The size of the femoral ACL footprint, length of Blumensaat's line, and the height and area of the lateral wall of the femoral intercondylar notch were measured with ImageJ software. RESULTS: Notch height, lateral notch area, and TEL were significantly correlated with the femoral ACL footprint area. Both axial notch area and notch outlet length were significantly correlated with the femoral mid-substance insertion area. CONCLUSION: Morphological evaluation using 3D-CT preoperatively may be useful in predicting the femoral ACL footprint size.

Morphological size evaluation of the mid-substance insertion areas and the fan-like extension fibers in the femoral ACL footprint.

PURPOSE: The purpose of this study was to evaluate the detailed anatomy of the femoral anterior cruciate ligament (ACL) insertion site, with special attention given to the morphology of the mid-substance insertion areas and the fan-like extension fibers. METHODS: Twenty-three non-paired human cadaver knees were used (7 Males, 16 Females, median age 83, range 69-96). All soft tissues around the knee were resected except the ligaments. The ACL was divided into antero-medial (AM) and postero-lateral (PL) bundles according to the difference in macroscopic tension patterns. The ACL was carefully dissected and two outlines were made of the periphery of each bundle insertion site: those which included and those which excluded the fan-like extension fibers. An accurate lateral view of the femoral condyle was photographed with a digital camera, and the images were downloaded to a personal computer. The area of each bundle, including and excluding the fan-like extension fibers, was measured with Image J software (National Institution of Health). The width and length of the mid-substance insertion sites were also evaluated using same image. RESULTS: The femoral ACL footprint was divided into four regions (mid-substance insertion sites of the AM and PL bundles, and fan-like extensions of the AM and PL bundles). The measured areas of the mid-substance insertion sites of the AM and PL bundles were 35.5 ± 12.5, and 32.4 ± 13.8 mm2, respectively. Whole width and length of the mid-substance insertion sites were 5.3 ± 1.4, and 15.5 ± 2.9 mm, respectively. The measured areas of the fan-like extensions of the AM and PL bundles were 27 ± 11.5, and 29.5 ± 12.4 mm2, respectively. CONCLUSION: The femoral ACL footprint was divided into quarters of approximately equal size (mid-substance insertion sites of the AM and PL bundles, and fan-like extensions of the AM and PL bundles). For clinical relevance, to perform highly reproducible anatomical ACL reconstruction, the presence of the fan-like extension fibers should be taken into consideration.