BACKGROUND: Anatomic footprint restoration of anterior cruciate ligament (ACL) is recommended during reconstruction surgery. The purpose of this study was to compare and analyze the femoral and tibial tunnel positions of transtibial single bundle (SB) and transportal double bundle (DB) ACL reconstruction using three-dimensional computed tomography (3D-CT). METHODS: In this study, 26 patients who underwent transtibial SB ACL reconstruction and 27 patients with transportal DB ACL reconstruction using hamstring autograft. 3D-CTs were taken within 1 week after the operation. The obtained digital images were then imported into the commercial package Geomagic Studio v10.0. The femoral tunnel positions were evaluated using the quadrant method. The mean, standard deviation, standard error, minimum, maximum, and 95% confidence interval values were determined for each measurement. RESULTS: The femoral tunnel for the SB technique was located 35.07% +/- 5.33% in depth and 16.62% +/- 4.99% in height. The anteromedial (AM) and posterolateral (PL) tunnel of DB technique was located 30.48% +/- 5.02% in depth, 17.12% +/- 5.84% in height and 34.76% +/- 5.87% in depth, 45.55% +/- 6.88% in height, respectively. The tibial tunnel with the SB technique was located 45.43% +/- 4.81% from the anterior margin and 47.62% +/- 2.51% from the medial tibial articular margin. The AM and PL tunnel of the DB technique was located 33.76% +/- 7.83% from the anterior margin, 45.56% +/- 2.71% from the medial tibial articular margin and 53.19% +/- 3.74% from the anterior margin, 46.00% +/- 2.48% from the medial tibial articular margin, respectively. The tibial tunnel position with the transtibial SB technique was located between the AM and PL tunnel positions formed with the transportal DB technique. CONCLUSIONS: Using the 3D-CT measuring method, the location of the tibia tunnel was between the AM and PL footprints, but the center of the femoral tunnel was at more shallow position from the AM bundle footprint when ACL reconstruction was performed by the transtibial SB technique.
Adult ; Anterior Cruciate Ligament Reconstruction/*methods ; *Femur/radiography/surgery ; Humans ; Imaging, Three-Dimensional/*methods ; Knee Joint/physiology ; Male ; Prospective Studies ; Surgery, Computer-Assisted/*methods ; *Tibia/radiography/surgery ; Tomography, X-Ray Computed

BACKGROUND: Regarding reconstruction surgery of the anterior cruciate ligament (ACL), there is still a debate whether to perform a single bundle (SB) or double bundle (DB) reconstruction. The purpose of this study was to analyze and compare the volume and surface area of femoral and tibial tunnels during transtibial SB versus transportal DB ACL reconstruction. METHODS: A consecutive series of 26 patients who underwent trantibial SB ACL reconstruction and 27 patients with transportal DB ACL reconstruction using hamstring autograft from January 2010 to October 2010 were included in this study. Three-dimensional computed tomography (3D-CT) was taken within one week after operation. The CT bone images were segmented with use of Mimics software v14.0. The obtained digital images were then imported in the commercial package Geomagic Studio v10.0 and SketchUp Pro v8.0 for processing. The femoral and tibial tunnel lengths, diameters, volumes and surface areas were evaluated. A comparison between the two groups was performed using the independent-samples t-test. A p-value less than the significance value of 5% (p < 0.05) was considered statistically significant. RESULTS: Regarding femur tunnels, a significant difference was not found between the tunnel volume for SB technique (1,496.51 +/- 396.72 mm3) and the total tunnel volume for DB technique (1,593.81 +/- 469.42 mm3; p = 0.366). However, the total surface area for femoral tunnels was larger in DB technique (919.65 +/- 201.79 mm2) compared to SB technique (810.02 +/- 117.98 mm2; p = 0.004). For tibia tunnels, there was a significant difference between tunnel volume for the SB technique (2,070.43 +/- 565.07 mm3) and the total tunnel volume for the DB technique (2,681.93 +/- 668.09 mm3; p < or = 0.001). The tibial tunnel surface area for the SB technique (958.84 +/- 147.50 mm2) was smaller than the total tunnel surface area for the DB technique (1,493.31 +/- 220.79 mm2; p < or = 0.001). CONCLUSIONS: Although the total femoral tunnel volume was similar between two techniques, the total surface area was larger in the DB technique. For the tibia, both total tunnel volume and the surface area were larger in DB technique.
Adult ; Anterior Cruciate Ligament/injuries/surgery ; Anterior Cruciate Ligament Reconstruction/*methods ; Autografts ; Femur/*radiography/surgery ; Humans ; Imaging, Three-Dimensional ; Male ; Tendon Injuries/*radiography/rehabilitation/surgery ; Tendons/transplantation ; Tibia/*radiography/surgery

Using computerized tomographic data and three dimensional model, we studied the influence of tibial intramedullary canal axis and other morphologic factors of the tibia on the entry point for tibial intramedullary alignment guides. Various anatomical parameters including tibial anteroposterior dimensions (AP), mediolateral dimensions (ML), aspect ratio (ML/AP), bowing and the intramedullary canal axis were studied. In addition, the entry point for the intramedullary alignment guide for primary and revision total knee arthroplasty were studied. The averaged entry point at the level of the tibial plateau was 5.7+/-2.2 mm anterior and 4.3+/-2.0 mm lateral to the classical entry point (P<.001). Furthermore, this entry point was more anterolateral in females when compared to males (P<.001). At a depth 10 mm below the tibial plateau, the entry point was on average 8.8+/-1.9 mm anterior and 2.9+/-1.9 mm lateral to the center of the cut surface. With increasing tibial varus the entry point tended to shift laterally at both levels (r=0.49) (P<.001). In Korean, the entry point for tibial intramedullary alignment systems is anterolateral to the classically described entry point. Moreover, the increment of tibial varus necessitates more lateral placement of the entry point. Intraoperatively, the entry point can be localized during primary knee arthroplasty to a point 15.9+/-2.8 mm anterior to and 1.2+/-2.8 mm lateral to the lateral tibial spine. For revision knee arthroplasty the point is on average 8.8+/-1.9 mm anterior and 2.9+/-1.9 mm lateral to the center of the cut surface of the tibia at a depth of 10 mm from the articular surface.
Arthroplasty ; Axis, Cervical Vertebra ; Female ; Humans ; Knee ; Male ; Spine ; Tibia

We measured the mediolateral (ML) and anteroposterior (AP) length, height and widths of the anterior, posterior and inferior section of the resected distal femurs using three dimensional computer tomographic measurements in 200 knees from 100 cadavers. We also calculated the aspect ratio (ML/AP) and compared the measured parameters with that of six conventionally used total knee femoral prostheses. We found that the average ML (70.2+/-5.5 mm) and AP (53.9+/-3.8 mm) dimensions from our study were lower than those reported from Western populations. The aspect ratio showed a progressive decline with an increasing antero-posterior dimension. All of the compared designs showed undersizing for the mediolateral dimension distally and for the widths of the resected medial and lateral posterior femoral condyles. But some of the compared designs showed oversizing for the height of the resected medial and lateral posterior femoral condyles. This study provides guidelines for designing a suitable femoral component for total knee prostheses that fit Asian populations.
Anthropometry ; Asian Continental Ancestry Group ; Cadaver ; Femur ; Humans ; Knee ; Knee Prosthesis ; Prostheses and Implants

BACKGROUND: Despite the importance of soft tissue balancing during total knee arthroplasty (TKA), all estimating techniques are dependent on a surgeon's manual distraction force or subjective feeling based on experience. We developed a new device for dynamic gap balancing, which can offer constant load to the gap between the femur and tibia, using pneumatic pressure during range of motion. METHODS: To determine the amount of distraction force for the new device, 3 experienced surgeons' manual distraction force was measured using a conventional spreader. A new device called the consistent load pneumatic tensor was developed on the basis of the biomechanical tests. Reliability testing for the new device was performed using 5 cadaveric knees by the same surgeons. Intraclass correlation coefficients (ICCs) were calculated. RESULTS: The distraction force applied to the new pneumatic tensioning device was determined to be 150 N. The interobserver reliability was very good for the newly tested spreader device with ICCs between 0.828 and 0.881. CONCLUSIONS: The new pneumatic tensioning device can enable us to properly evaluate the soft tissue balance throughout the range of motion during TKA with acceptable reproducibility.
Arthroplasty, Replacement, Knee/*instrumentation/methods ; Biomechanics ; Equipment Design ; Femur/surgery ; Humans ; Knee Joint/physiology/*surgery ; Mechanical Processes ; Range of Motion, Articular ; Reproducibility of Results ; Tibia/surgery

Background: The increasing prevalence of cementless total knee arthroplasty (TKA) necessitates a reliable assessment of bone quality. Central bone mineral density (BMD), measured by dual-energy x-ray absorptiometry (DEXA) in the lumbar spine and hip, is conventionally used to estimate bone quality. However, its effectiveness in predicting the actual bone strength at the knee, which is crucial for cementless TKA, is under scrutiny. This study investigated the relationship between central BMD and actual bone strength at the knee. Methods: This prospective study included 191 knees undergoing standard posterior-stabilized TKA between November 2021 and March 2023. Central BMD was assessed 3 months before TKA, and the failure load of bone fragments collected during box preparation was directly measured using an indentation test. Relationships between central BMD and failure load as a measure of the actual bone strength at the knee were analyzed. Results: Linear regression analysis revealed a weak correlation between central BMD and the actual bone strength at the knee (R 2= 0.146 in all patients; < 0.001 in osteoporosis group; 0.126 in non-osteoporosis group). The correlation suggested by the regression models was particularly insignificant in the osteoporosis subgroup, showing that central BMD is not a reliable predictor of bone strength for cementless TKA. Conclusions Central BMD measurements have limited utility in accurately predicting the real bone strength at the knee for cementless TKA. This study highlights the need for more specific and direct methods of assessing bone quality at the knee to ensure the success of cementless TKA.

Background: The increasing prevalence of cementless total knee arthroplasty (TKA) necessitates a reliable assessment of bone quality. Central bone mineral density (BMD), measured by dual-energy x-ray absorptiometry (DEXA) in the lumbar spine and hip, is conventionally used to estimate bone quality. However, its effectiveness in predicting the actual bone strength at the knee, which is crucial for cementless TKA, is under scrutiny. This study investigated the relationship between central BMD and actual bone strength at the knee. Methods: This prospective study included 191 knees undergoing standard posterior-stabilized TKA between November 2021 and March 2023. Central BMD was assessed 3 months before TKA, and the failure load of bone fragments collected during box preparation was directly measured using an indentation test. Relationships between central BMD and failure load as a measure of the actual bone strength at the knee were analyzed. Results: Linear regression analysis revealed a weak correlation between central BMD and the actual bone strength at the knee (R 2= 0.146 in all patients; < 0.001 in osteoporosis group; 0.126 in non-osteoporosis group). The correlation suggested by the regression models was particularly insignificant in the osteoporosis subgroup, showing that central BMD is not a reliable predictor of bone strength for cementless TKA. Conclusions Central BMD measurements have limited utility in accurately predicting the real bone strength at the knee for cementless TKA. This study highlights the need for more specific and direct methods of assessing bone quality at the knee to ensure the success of cementless TKA.

Background: The increasing prevalence of cementless total knee arthroplasty (TKA) necessitates a reliable assessment of bone quality. Central bone mineral density (BMD), measured by dual-energy x-ray absorptiometry (DEXA) in the lumbar spine and hip, is conventionally used to estimate bone quality. However, its effectiveness in predicting the actual bone strength at the knee, which is crucial for cementless TKA, is under scrutiny. This study investigated the relationship between central BMD and actual bone strength at the knee. Methods: This prospective study included 191 knees undergoing standard posterior-stabilized TKA between November 2021 and March 2023. Central BMD was assessed 3 months before TKA, and the failure load of bone fragments collected during box preparation was directly measured using an indentation test. Relationships between central BMD and failure load as a measure of the actual bone strength at the knee were analyzed. Results: Linear regression analysis revealed a weak correlation between central BMD and the actual bone strength at the knee (R 2= 0.146 in all patients; < 0.001 in osteoporosis group; 0.126 in non-osteoporosis group). The correlation suggested by the regression models was particularly insignificant in the osteoporosis subgroup, showing that central BMD is not a reliable predictor of bone strength for cementless TKA. Conclusions Central BMD measurements have limited utility in accurately predicting the real bone strength at the knee for cementless TKA. This study highlights the need for more specific and direct methods of assessing bone quality at the knee to ensure the success of cementless TKA.

Background: The increasing prevalence of cementless total knee arthroplasty (TKA) necessitates a reliable assessment of bone quality. Central bone mineral density (BMD), measured by dual-energy x-ray absorptiometry (DEXA) in the lumbar spine and hip, is conventionally used to estimate bone quality. However, its effectiveness in predicting the actual bone strength at the knee, which is crucial for cementless TKA, is under scrutiny. This study investigated the relationship between central BMD and actual bone strength at the knee. Methods: This prospective study included 191 knees undergoing standard posterior-stabilized TKA between November 2021 and March 2023. Central BMD was assessed 3 months before TKA, and the failure load of bone fragments collected during box preparation was directly measured using an indentation test. Relationships between central BMD and failure load as a measure of the actual bone strength at the knee were analyzed. Results: Linear regression analysis revealed a weak correlation between central BMD and the actual bone strength at the knee (R 2= 0.146 in all patients; < 0.001 in osteoporosis group; 0.126 in non-osteoporosis group). The correlation suggested by the regression models was particularly insignificant in the osteoporosis subgroup, showing that central BMD is not a reliable predictor of bone strength for cementless TKA. Conclusions Central BMD measurements have limited utility in accurately predicting the real bone strength at the knee for cementless TKA. This study highlights the need for more specific and direct methods of assessing bone quality at the knee to ensure the success of cementless TKA.

OBJECTIVE: To clarify the landmark for deciding the entry point for C1 lateral mass screws via the posterior arch by using 3-dimensional (3D) computed images. METHODS: Resnick insisted that the C1 posterior arch could be divided into pure posterior and lateral lamina (C1 pedicle). Authors studied where this transition point (TP) is located between the posterior lamina and the C1 pedicle and how it can be recognized. The 3D computed images of 86 cadaver C1s (M : F=45 : 41) were used in this study. RESULTS: The superior ridge of the C1 posterior arch had 2 types of orientation. One was in the vertical direction in the C1 posterior lamina and the other was in the horizontal direction in the C1 pedicle. The TP was located at the border between the 2 areas, the same site as the posterior end of the groove of the vertebral artery. On posterior-anterior projection, the posterior arch was sharpened abruptly at TP. We were unable to identify the TP in 6.4% of specimens due to complete or partial osseous bridges. A total of 93.8% of the TP were located between the most enlarged point of the spinal canal and the medial wall of the vertebral artery. CONCLUSION: The anatomic entry zone of C1 lateral laminar screws was clarified and identified based on the TP by using preoperative 3D computed images.
Cadaver ; Spinal Canal ; Vertebral Artery