Transtibial Posterior Cruciate Ligament Reconstruction Research Articles

An in-vitro three-dimensional surgical simulation technique to predict tibial tunnel length in transtibial posterior cruciate ligament reconstruction

BackgroundDuring the transtibial posterior cruciate ligament (PCL) reconstruction, drilling depth excessively longer than the tibial tunnel length (TTL) is an important reason to cause popliteal neurovascular bundle injury when preparing the tibial tunnel. This study aims to develop an in-vitro three-dimensional surgical simulation technique to determine the TTL in anteromedial (AM) and anterolateral (AL) approaches.MethodsA total of 63 knees’ 3-dimensional (3D) computed tomography models were included in this study. The SuperImage system was used to reconstruct the 3D knee model and locate the tibial PCL site. The established 3D knee model and the coordinates of the tibial PCL site were imported into Rhinoceros 3D modeling software to simulate AM and AL tibial tunnel approaches with different tibial tunnel angles (TTA). The TTL and the tibial tunnel height (TTH) were measured in this study.ResultsIn AM and AL tibial tunnel approaches, the TTL showed a strong correlation with the TTA (for AM: r = 0.758, p < 0.001; for AL: r = 0.727, p < 0.001). The best fit equation to calculate the TTL based on the TTA was Y = 1.04X + 14.96 for males in AM approach, Y = 0.93X + 17.76 for males in AL approach, Y = 0.92X + 14.4 for females in AM approach, and Y = 0.94X + 10.5 for females in AL approach.ConclusionMarking the TTL on the guide pin or reamer could help to avoid the drill bit over-penetrated into the popliteal space to damage the neurovascular structure.

The optimal tibial tunnel placement to maximize the graft bending angle in the transtibial posterior cruciate ligament reconstruction: a quantitative assessment in three-dimensional computed tomography model.

The graft bending angle created by the graft and the tibial tunnel has inevitably occurred during the transtibial posterior cruciate ligament (PCL) reconstruction. However, few studies quantitively analyzed this angle. This study aimed to (I) explore the optimal tibial tunnel placement to maximize the graft bending angle in the PCL reconstruction; (II) reveal the effect of the tibial tunnel placement on the graft bending angle. This was an in-vitro surgical simulation study based on the three-dimensional (3D) computed tomography (CT). A total of 55 patients who took CT scanning for knee injuries were selected (April 2020 to January 2022) from the local hospital database for review. The 3D knee models were established on the Mimics software based on the knees' CT data. Using the Rhinoceros software to simulate the transtibial PCL reconstruction on the 3D CT knee model. The anteromedial and anterolateral tibial tunnel approaches were simulated with different tibial tunnel angle. The graft bending angle and tibial tunnel length (TTL) with different tibial tunnel angles were quantitively analyzed. The graft bending angle in anterolateral approach with a 50° tibial tunnel angle was significantly greater than it in anteromedial approach with a 60° tibial tunnel angle (P<0.001). There was no difference of the graft bending angle between the anterolateral approach with a 40° tibial tunnel angle and the anteromedial approach with a 60° tibial tunnel angle (P>0.05). The graft bending angle showed a strong correlation with the tibial tunnel angle (for anteromedial approach: r=0.759, P<0.001; for anterolateral approach: r=0.702, P<0.001). The best-fit equation to calculate the graft bending angle based on the tibial tunnel angle was Y = 0.89*X + 59.05 in anteromedial tibial tunnel approach (r2=0.576), and was Y = 0.78*X + 80.21 anterolateral tibial tunnel approach (r2=0.493). The graft bending angle and TTL will significantly increase as the tibial tunnel angle becomes greater. Maximizing the tibial tunnel angle (50° tibial tunnel angle) in the anterolateral approach could provide the greatest graft bending angle in the PCL reconstruction. No matter how the tibial tunnel angle is changed in the anteromedial approach, using anterolateral approach might reduce the killer turn effect more effectively than using anteromedial approach.

The tibial tunnel drilling angles of 60° provided a lower ultimate load to failure on a single bundle posterior cruciate ligament graft using interference screw fixation compared to 30°/45°.

To biomechanically compare the initial fixation strength of grafts among three tibial tunnel angles (30°/45°/60°) in transtibial posterior cruciate ligament (PCL) reconstruction. A series of transtibial PCL reconstruction models were established with porcine tibias and bovine tendons. Specimens were randomly assigned to three groups according to the angles between the tibial tunnel and the perpendicular line of the tibial shaft: Group A (30°, n = 12), Group B (45°, n = 12), and Group C (60°, n = 12). The area of the tunnel entrance, the segmental bone mineral density (sBMD) of the graft fixation site of the tibia and the maximum insertion torque of the interference screw were measured. Finally, load to failure tests were carried out on the graft-screw-tibia constructs at the same rate. Ultimate load to failure in Group C (335.2 ± 107.5 N) was significantly lower than that in Group A (584.1 ± 127.9 N, P < 0.01) and Group B (521.9 ± 95.9 N, P < 0.01). There were no significant differences between biomechanical properties of Groups A and B (n.s.). The posterior part fractures of the tibial tunnel exit occurred in eight specimens of Group C. In addition, the ultimate load was proven to be related to insertion torque (rho = 0.7, P < 0.01), sBMD (rho = 0.7, P < 0.01), and the area of the tunnel entrance (rho =-0.4, P = 0.01). The ultimate load to failure was significantly lower in tibial PCL interference screw fixation for tunnels drilled at 60° compared to 30°/45°. In addition, the ultimate load was significantly correlated with insertion torque, sBMD and the area of the tunnel entrance. Given that the load to failure of distal fixation may not be sufficient for early postoperative rehabilitation, a 60° tunnel should not be recommended to drill in tibia during PCL reconstruction.

Biomechanical Comparison of Anatomic Versus Lower of Anteromedial and Anterolateral Tibial Tunnels in Posterior Cruciate Ligament Reconstruction.

In order to reduce the "killer turn" effect, various tibial tunnels have been developed. However, few studies investigated the biomechanical effects of different tibial tunnels during PCL reconstruction. This study aims to compare the time-zero biomechanical properties of anteromedial, anterolateral, lower anteromedial, and lower anterolateral tibial tunnels in transtibial posterior cruciate ligament (PCL) reconstruction under load-to-failure loading. Porcine tibias and bovine extensor tendons were used to simulate in vitro transtibial PCL reconstruction. Forty bovine extensor tendons and 40 porcine tibias were randomly divided into four experimental groups: anteromedial tunnel group (AM group, n=10), anterolateral tunnel group (AL group, n=10), lower anteromedial tunnel group (L-AM group, n=10), and lower anterolateral tunnel group (L-AL group, n=10). The biomechanical test was then carried out in each group using the load-to-failure test. The ultimate load (in newtons), yield load (in newtons), tensile stiffness (in newtons per millimeter), load-elongation curve, failure mode, and tibial tunnel length (in millimeter) were recorded for each specimen. One-way analysis of variance (ANOVA) was used to compare the mean differences among the four groups. The biomechanical outcomes showed that there were no differences in the mean tensile stiffness and failure mode among four groups. The ultimate load and yield load of the L-AM group were significantly higher than those of other three groups (P < 0.05). For the AM group, its ultimate load is significantly higher than that of the L-AL group (P < 0.05), and its yield load is higher than that of the AL group and L-AL group (P < 0.05). However, we found no significant differences in either ultimate load or yield load between AL group and L-AL group (P > 0.05). There was significant statistical difference in the length of tibial tunnel between anatomic groups (AM and AL) and lower groups (L-AM and L-AL) (P < 0.05). Compared with the anteromedial, anterolateral, and lower anterolateral tibial tunnel, the lower anteromedial tibial tunnel showed better time-zero biomechanical properties including ultimate load and yield load in transtibial PCL reconstruction.

Biomechanical comparison of proximal, distal, and anatomic tibial tunnel for transtibial posterior cruciate ligament reconstruction.

No consensus has been reached on the optimal position of PCL tibial tunnel. The purpose of this study was to compare the biomechanical properties of proximal, distal and anatomic tibial tunnel in transtibial posterior cruciate ligament reconstruction. An in-vitro model of transtibial posterior cruciate ligament reconstruction was simulated using porcine tibias and bovine extensor tendons. Two models of biomechanical testing, load-to-failure loading, and cyclic loading, were performed in this study. The load-to-failure loading found that distal tibial tunnel resulted in greater ultimate load and yield load than the anatomic and proximal tunnel group (p < 0.05), whereas there were no significant differences in mean tensile stiffness among three groups (p > 0.05). The cyclic loading found no differences in the graft displacement at 250, 500, and 1000 cycles among three groups (p > 0.05). It was found that distal tibial tunnel showed superior ultimate load and yield load in load-to-failure loading testing compared with proximal and anatomic tibial tunnels, whereas no significant difference was found in terms of the mean displacement of the survived grafts in cyclic loading testing among three groups.

3D Killer Turn Angle in Transtibial Posterior Cruciate Ligament Reconstruction Is Determined by the Graft Turning Angle both in the Sagittal and Coronal Planes.

ObjectiveDuring the transtibial posterior cruciate ligament (PCL) reconstruction, surgeons commonly pay more attention to the graft turning angle in the sagittal plane (GASP), but the graft turning angle in the coronal plane (GACP) is always neglected. This study hypothesized that the three‐dimensional (3D) killer turn angle was determined by both the GASP and GACP, and aimed to quantitively analyze the effects of the GASP and GACP on the 3D killer turn angle.MethodsThis was an in‐vitro computer simulation study of transtibial PCL reconstruction using 3D knee models. Patients with knee injuries who were CT scanned were selected from the CT database (April 2019 to January 2021) at a local hospital for reviewing. A total of 60 3D knees were simulated based on the knees' CT data. The femoral and tibial PCL attachment were located on the 3D knee model using the Rhinoceros software. The tibial tunnels were simulated based on different GASP and GACP. The effects of the GASP and GACP on the 3D killer turn angle were quantitatively analyzed. One‐way analysis of variance was used to compare the outcomes in different groups. The regression analysis was performed to identify variables of the GASP and GACP which significantly affected 3D killer turn angle.ResultsThe 3D killer turn angle showed a significant proportional relationship not only with the GASP (r 2 > 0.868, P < 0.001), but also with the GACP (r 2 > 0.467, P < 0.001). Every 10° change of the GACP caused 2.8° to 4.4° change of the 3D killer turn angle, whereas every 10° change of the GASP caused 6.4° to 9.2° change of the 3D killer turn angle.ConclusionsThe 3D killer turn angle was significantly affected by both the GASP and GACP. During the transtibial PCL reconstruction, the proximal anterolateral tibial tunnel approach could increase the 3D killer turn angle more obviously compared with the most distal anteromedial tibial tunnel approach. To minimize the killer turn effect, both the GASP and GACP were required to be considered to increase.

The Permissive Safe Angle of the Tibial Tunnel in Transtibial Posterior Cruciate Ligament Reconstruction: A Three-Dimensional Simulation Study.

ObjectiveTo determine the permissive safe angle (PSA) of the tibial tunnel in transtibial posterior cruciate ligament (PCL) reconstruction based on a three‐dimensional (3D) simulation study.MethodsThis was a computer simulation study of transtibial PCL reconstruction using 3D knee models. CT images of 90 normal knee joints from 2017 to 2020 were collected in this study, and 3D knee models were established based on CT data. The tunnel approaches were subdivided into the anterior 1/3 of the anteromedial tibia (T1), middle 1/2 of the anteromedial tibia (T2), the tibial crest (T3), anterior 1/3 of the anterolateral tibia (T4), middle 1/2 of the anterolateral tibia (T5). Five tibial tunnels (T1–T5) were simulated on the 3D knee models. The PSAs, in different tibial tunnel approaches were measured, and subgroup analyses of sex, age and height were also carried out.ResultsThe mean PSAs of the tibial tunnels with 5 different approaches (T1–T5) were 58.49° ± 6.82°, 61.14° ± 6.69°, 56.12° ± 7.53°, 52.01° ± 8.89° and 49.90° ± 10.53°, respectively. The differences of the mean PSAs between the anteromedial and anterolateral approaches were significant (P < 0.05). However, there was no significant difference of the mean PSA value between the two anteromedial tibial tunnel approaches (T1–T2) (P > 0.05), as well as between the two anterolateral tibial tunnel approaches (T4–T5). The patient's anthropomorphic characteristics of sex, age, and height were not associated with the PSAs.ConclusionsThe PSA varied with the anteromedial, tibial crest and anterolateral approaches for transtibial PCL reconstruction, and surgeons should limit the PCL drill guide by referring to the specific PSA for different surgical approaches.

An Anatomically Placed Tibial Tunnel does not Completely Surround a Simulated PCL Reconstruction Graft in the Proximal Tibia.

It is hypothesized that anatomic tunnel placement will create tunnels with violation of the posterior cortex and subsequently an oblique aperture that is not circumferentially surrounded by bone. In this article, we aimed to characterize posterior cruciate ligament (PCL) tibial tunnel using a three-dimensional (3D) computed tomography (CT) model. Ten normal knee CTs with the patella, femur, and fibula removed were used. Simulated 11 mm PCL tibial tunnels were created at 55, 50, 45, and 40 degrees. The morphology of the posterior proximal tibial exit was examined with 3D modeling software. The length of tunnel not circumferentially covered (cortex violation) was measured to where the tibial tunnel became circumferential. The surface area and volume of the cylinder both in contact with the tibial bone and that not in contact with the tibia were determined. The percentages of the stick-out length surface area and volume not in contact with bone were calculated. The mean stick-out length of uncovered graft at 55, 50, 45, and 40 degrees were 26.3, 20.5, 17.3, and 12.7 mm, respectively. The mean volume of exposed graft at 55, 50, 45, and 40 degrees were 840.8, 596.2, 425.6, and 302.9 mm3, respectively. The mean percent of volume of exposed graft at 55, 50, 45, and 40 degrees were 32, 29, 25, and 24%, respectively. The mean surface of exposed graft at 55, 50, 45, and 40 degrees were 372.2, 280.4, 208.8, and 153.3 mm2, respectively. The mean percent of surface area of exposed graft at 55, 50, 45, and 40 degrees were 40, 39, 34, and 34%, respectively. Anatomic tibial tunnel creation using standard transtibial PCL reconstruction techniques consistently risks posterior tibial cortex violation and creation of an oblique aperture posteriorly. This risk is decreased with decreasing the angle of the tibial tunnel, though the posterior cortex is still compromised with angles as low as 40 degrees. With posterior cortex violation, a surgeon should be aware that a graft within the tunnel or socket posteriorly may not be fully in contact with bone. This is especially relevant with inlay and socket techniques.

No difference in subjective and objective clinical outcomes between arthroscopic transtibial and open inlay posterior cruciate ligament reconstruction techniques in the treatment of multi-ligamentous knee injuries

BackgroundThere is controversy regarding the optimal treatment of posterior cruciate ligament (PCL) -based multi-ligamentous injuries. The purpose of this study was to compare the subjective and objective clinical outcomes of arthroscopic transtibial reconstruction and tibial inlay reconstruction. MethodsFrom 2005 to 2013, a total of 135 patients with PCL-based multi-ligamentous injuries were consecutively identified. Patients were operated with the arthroscopic transtibial technique or the open tibial inlay technique group. Other injured structures were reconstructed or repaired simultaneously. All of the patients underwent a preoperative and postoperative physical examination, KT-1000 measurement, stress radiography under anesthesia and subjective evaluations including Tegner score, Lysholm score, American Academy of Orthopedic Surgeons (AAOS) score. ResultsFifty-seven patients (64.8%) underwent arthroscopic transtibial PCL reconstruction, and 31 patients (35.2%) underwent PCL reconstruction with the tibial inlay technique. The average follow up period was 45.9 ± 17.0 months (24–77 months). At the final follow up, for the arthroscopic transtibial group, the side-to-side difference of KT-1000 decreased from 13.5 ± 4.8 mm to 2.4 ± 3.4 mm (P < 0.001); the tibial posterior translation by stress radiograph decreased from 14.9 ± 7.1 mm to 4.6 ± 4.0 mm (P < 0.001). For the open inlay group, the side-to-side difference of KT-1000 decreased from 13.7 ± 5.2 mm to 2.2 ± 3.6 mm (P < 0.001) and the posterior translation by stress radiograph decreased from 14.9 ± 5.9 mm to 4.3 ± 3.9 mm (P < 0.001) at the final follow up. The inter-group clinical outcomes pre- and postoperatively were not significantly different at any time point. ConclusionThere was no statistically significant difference in objective and subjective outcome between the arthroscopic transtibial and open inlay PCL reconstruction in patients with multi-ligamentous injuries.

Transtibial Posterior Cruciate Ligament Reconstruction.

The keys to successful posterior cruciate ligament (PCL) reconstruction are to identify and treat all pathology, utilize strong graft material, accurately place tunnels in anatomic insertion sites, minimize graft bending, mechanical graft tensioning, secure graft fixation, and the appropriate postoperative rehabilitation program. Adherence to these technical principles results in successful single- and double-bundle arthroscopic transtibial tunnel PCL reconstruction based upon stress radiography, arthrometer, knee ligament rating scales, and patient satisfaction measurements. The purpose of this manuscript is to describe the arthroscopic transtibial tunnel posterior cruciate ligament reconstruction surgical technique.

Outcomes of trans-tibial posterior cruciate ligament reconstruction using a fovea landmark technique in relation to tunnel position and serial tunnel configuration

PurposeTo evaluate (1) the outcome of PCL reconstruction with tibial suspensory fixation using a fovea landmark technique based on the tunnel position and serial change of the tunnel configuration after trans-tibial PCL reconstruction, and (2) whether suspensory fixation has any harmful effect on the outcome. MethodsA total of 48 knees that underwent PCL reconstruction were included. The tunnel position was analyzed using CT. To analyze the tunnel configuration, the tunnel diameter, area, and volume were measured. To evaluate the outcome, pre- and postoperative International Knee Documentation Committee (IKDC) and Lysholm scores were analyzed. To evaluate stability, a side-to-side difference was evaluated using Telos stress radiographs. ResultsThe greatest configurational change occurred at the mid-portion of tibial tunnel. There was a correlation between stability and tibial tunnel mid-portion configurational change (p < 0.01). Important correlations were found between the tunnel position and serial tunnel configuration between high femoral tunnel and widest site of femoral tunnel and tibia aperture (p < 0.01 and 0.04, respectively). The diameter of widest site of tibia tunnel increased when the tibia tunnel center moved toward the posterior margin of the tibia (p = 0.02) and the percentage of femoral tunnel volume enlargement increased when the tibia tunnel center moved toward the medial edge of the PCL fovea (p = 0.02). ConclusionsA high femoral tunnel, medial tibial tunnel, and posterior tibial tunnel were related to the serial configurational change. A suspensory tibial fixation produced significant configurational change around the mid-portion of the tibial tunnel, and it induced a negative effect on stability.Level of Evidence: Level IV.

Remnant-Preserving Posterior Cruciate Ligament Reconstruction Over Remnant Fibers Using a Figure-of-Four Position and a Posterior Trans-Septal Portal.

Anatomic tunnel formation and remnant preservation are the recent trends in posterior cruciate ligament (PCL) reconstruction. However, it is difficult to observe the anatomical PCL footprint and perform the operation in the process of remnant‐preserving PCL reconstruction. This study describes a single‐bundle, transtibial PCL reconstruction technique with anatomic graft passage over the remnant PCL fibers. A femoral tunnel of PCL is created at 2 mm medial to the roof of the intercondylar notch and 3 mm proximal to the margin of the articular cartilage. The tibial insertion of PCL is observed using a figure‐of‐four position through a posterior trans‐septal portal. A tibial bone tunnel is made below the distal center portion of the tibial insertion of residual PCL fibers. The graft is passed over the PCL through the tibial bone tunnel, the space between the anterior cruciate ligament (ACL) and the residual PCL fibers, to the femoral socket and is fixed by the EndoButton and screw. This technique is able to ensure a reasonable intra‐articular length and optimal isometry. It has been applied in patients with PCL rupture and posterior instability of the knee joint, and no intraoperative or postoperative complications occurred. Our technology provides a valuable new treatment option for PCL rupture. Future comparative studies are needed to further clarify its beneficial effect.

PCL Transtibial Tunnel Reconstruction.

The keys to successful posterior cruciate ligament (PCL) reconstruction are to identify and treat all pathology, use strong graft material, accurately place tunnels in anatomic insertion sites, minimize graft bending, mechanical graft tensioning, secure graft fixation, and the appropriate postoperative rehabilitation program. Adherence to these technical principles results in successful single and double bundle arthroscopic transtibial tunnel PCL reconstruction based upon stress radiography, arthrometer, knee ligament rating scales, and patient satisfaction measurements. The purpose of this article is to describe the arthroscopic transtibial tunnel PCL reconstruction surgical technique.

Return to Sports and Clinical Outcomes After Arthroscopic Anatomic Posterior Cruciate Ligament Reconstruction With Remnant Preservation

To evaluate the clinical outcomes of transtibial posterior cruciate ligament reconstruction (PCLR) with remnant preservation in highly active patients and to investigate the rate of return to sports (RTS), quality of sports activities, and patient satisfaction. Patients with a Tegner activity scale of >5 who underwent isolated PCLR from 2013 to 2016 with minimum 2-year follow-up were retrospectively reviewed. Single-bundle PCLR was performed using fresh frozen allograft irradiated with 50kGy. Subjective assessments included the Lysholm score, subjective International Knee Documentation Committee score, and Tegner activity scale. A questionnaire elicited information associated with RTS and satisfaction. Functional tests included isokinetic muscle strength and single-leg hop tests. We evaluated 52patients, with a mean (± standard deviation) follow-up duration of 29.5 ± 8.6months. The subjective assessments andfunctional tests significantly improved postoperatively (all P < .001). Mean time to return to full sports activity was 9.7± 5.1months. Thirty-eight (73.1%) and 45 (86.5%) patients could return to previous sports activities at 9 and 24months, respectively. A sports-experience questionnaire indicated that 48% and 69.2% of the patients were participating with unlimited effort and performance, respectively, and no pain at 9 and 24months. Multivariate analysis indicated that extensor deficit (odds ratio [OR] 4.2, 95% confidence interval [CI] 1.342 to 17.839), flexor deficit at 60°/s (OR 3.8, 95% CI 1.081 to 14.476), Limb Symmetry Index (%) for the single-leg vertical jump test (OR 2.2, 95% CI 1.212 to 9.227), and satisfaction (OR 2.8, 95% CI 1.186 to 10.281) were significantly associated with failure of not returning to preinjury sports activity levels at the 9-month follow-up. Arthroscopic anatomic PCLR with remnant preservation showed high rates of RTS and high patient satisfaction, as well as satisfactory clinical results in highly active patients. This surgical technique could be an effective treatment for grade III posterior cruciate ligament injury in highly active patients. Level IV, therapeutic case series.

Proximal, Distal, and Combined Fixation Within the Tibial Tunnel in Transtibial Posterior Cruciate Ligament Reconstruction: A Time-Zero Biomechanical Study In Vitro

To compare the time-zero biomechanical properties of 3 graft fixation techniques (proximal, distal, and combined fixation) within the tibial tunnel in transtibial posterior cruciate ligament (PCL) reconstruction. Porcine tibias and bovine extensor tendons were used to simulate a transtibial PCL reconstruction invitro. Load-to-failure testing was carried out in 3 groups: distal fixation alone (group I, n= 10), proximal fixation alone (group II, n= 10), and combined fixation (group III, n= 10). The load-elongation curve, tensile stiffness (in newtons per millimeter), ultimate load (in newtons), yield load (in newtons), energy absorbed to failure (in joules), and failure mode were recorded. All graft-tibia complexes failed because the grafts slipped past the interference screws. The tensile stiffness, yield load, and energy absorption in group I were significantly lower than those in group II and group III (tensile stiffness, 19.25 ± 9.68N/mm in group I vs 34.92 ± 16.48N/mm in group II [P= .016] and 32.31 ± 13.79N/mm in group III [P= .041]; yield load, 265.36 ± 144.52N in group I vs 398.23 ± 57.04N in group II [P= .006] and 424.94 ± 74.00N in group III [P= .001]; and energy absorption, 5.16 ± 2.35J in group I vs 19.95 ± 3.48J in group II [P < .001] and 21.09 ± 4.29J in group III [P < .001]). No statistically significant differences in biomechanical properties were found between group II and group III (P > .05). Compared with distal fixation in transtibial PCL reconstruction, proximal fixation and combined fixation showed superior time-zero biomechanical properties. Proximal fixation and combined fixation produced superior biomechanical properties to distal fixation in transtibial PCL reconstruction.

Evaluation of the permissible maximum angle of the tibial tunnel in transtibial anatomic posterior cruciate ligament reconstruction by computed tomography.

Excessive angle of the tibial tunnel may cause breakage of the posterior cortex in transtibial anatomic posterior cruciate ligament (PCL) reconstruction. However, a few studies have determined the permissible maximum angle of the tibial tunnel. The purpose of this study was to determine the permissible maximum angle of the tibial tunnel relative to the tibial plateau in transtibial anatomic PCL reconstruction and characterize the anatomic parameters of the tibial PCL attachment position. Computed tomography (CT) scans of a consecutive series of 408 adult knees with normal PCL attachment were measured. The parameters measured were the permissible maximum angle (PMA) of the 10mm-diameter tibial tunnel relative to the tibial plateau, the distance from the anterior orifice of the tibial tunnel to the tibial tuberosity (OTD), the anterior-posterior diameter (APD) of the tibial plateau, the distance from the center of PCL attachment site to the posterior edge of the tibial plateau (PPED), and the angle between the tibial plateau and the posterior tibial slope where the PCL insertion site was (PSA). Subgroup analysis was performed to determine the correlations between parameters, and sex, age, and height. The measurement reliability was evaluated by intraclass correlation coefficients (ICCs). The average value of PMA was 48.2 ± 5.4°, and it was not affected by sex, age, and height (P > 0.05). The values of OTD, APD, PPED, PSA, and height were significantly higher in males than females (OTD, P < 0.01; APD, P < 0.01; PPED, P < 0.01; PSA, P = 0.019; height, P < 0.01). With regard to age, we stratified the cases into three groups: the young (18-30years old), the middle-aged (31-45years old), and the elderly (46-60years old). The mean value of OTD, APD, and height were significantly lower in the elderly than that in the middle-aged (P < 0.01, P < 0.01, P < 0.01, respectively). With regard to height, we stratified the cases into three groups: ~ 1.65m (1), 1.66 ~ 1.75m (2), and 1.76m ~ (3). The mean value of OTD, APD, and PPED significantly increased with height, P < 0.05. The mean value of PSA was significant higher in II group than that in I group (P = 0.034). There should be a limit to the angle of the tibial tunnel in transtibial anatomic PCL reconstruction to prevent the fracture of posterior tunnel wall. The permissible maximum angle (PMA) of the 10mm-diameter tibial tunnel relative to the tibial plateau was 48.2°. Besides, the determination of the value of OTD, APD, PPED, and PSA could provide a clinical reference to insertion site, depth, and angle of the tibial drill guide in PCL reconstruction.

Evaluation of the theoretical optimal angle of the tibial tunnel in transtibial anatomic posterior cruciate ligament reconstruction by computed tomography

Background“Killer turn” effect is a critical explanation for the recurrent posterior laxity following transtibial posterior cruciate ligament (PCL) reconstruction, which affected by the angle of the tibial tunnel. Meanwhile, excessive tunnel angle would have an adverse impact on the healing of tendon to bone. The purpose was to evaluate the theoretical optimal angle of the tibial tunnel in transtibial anatomic PCL reconstruction.MethodsThe measurements were performed on CT sagittal plane, including the thickness of cancellous bone (L1), the theoretical optimal angle of the tibial tunnel (TOA, which was measured between tibial plateau and the extension cord connecting the center of PCL insertion site with a point 5 mm superior from marrow cavity vertex), L2 - the distance from anterior tunnel aperture to anterior end of tibial plateau, L3 - the distance from anterior tunnel aperture to tibial tuberosity (lowest edge of patellar ligament attachment).ResultsThe value of TOA and L3 were 35.4 ± 7.9 ° and 26.8 ± 11.4 mm, respectively. L1 and L2 were higher in males than females (L1, P = 0.002; L2, P = 0.046). Regarding age, L1, TOA, L2 and L3 were higher in the 46–60 years group than 31–45 years group (P = 0.02, P = 0.001, P = 0.038, P = 0.032, respectively). With regard to height, L1 was lower in group I - < 1.66 m than group II - 1.66 to 1.75 m and group III - > 1.75 m (I v II, P = 0.015, I v III, P = 0.026). L2 was also lower in group I than group II and group III (I v II, P = 0.026, I v III, P = 0.006). TOA and L3 showed no significant differences among sex and height groups (P > 0.05).ConclusionsTOA (35.4 ° ± 7.9 °) and L3 (26.8 ± 11.4 mm) could be used as a reference for ideal tibial tunnel placement in transtibial anatomic PCL reconstruction, so as to prevent recurrent PCL laxity and ensure good graft healing. However, further clinical validation is needed.

Graft sources do not affect to the outcome of transtibial posterior cruciate ligament reconstruction: a systematic review.

Despite numerous published reports on posterior cruciate ligament (PCL) reconstruction in the past 30 years, the ideal graft source remains unclear, and few objective scientific data have been published that thoroughly evaluate the long-term outcomes according to the graft source. We, therefore, conducted a systematic review of available high-quality comparative studies that evaluated clinical and objective stability testing to compare the different graft sources for PCL reconstruction. Eight articles were included in the final analysis. There were two level II and six level III studies. Autograft included 4-strand hamstring grafts (SHGs), 7-SHGs, quadriceps tendon, and patellar tendon. Allografts included Achilles tendon and tibialis anterior tendon. Hybrid graft and a ligament advanced reinforcement system (LARS) were used in one study each. Comparison was performed between autografts and allografts in three studies, between different autografts in two studies, between autograft and LARS in one study, among three different grafts in one study, and between 4 and 7-SHGs in one study. Most studies reported no statistically significant differences in the clinical results, except for one study that compared 4- and 7-SHG. Stability was similar or superior in a comparison between autografts and allografts, and was not statistically different between different autografts or between 4-SHG and LARS. However, more-stranded HG showed better stability than that of the less-stranded HG. Complications were more frequent with autografts. Using a comprehensive analysis of the current literature, the authors could not identify an individual graft source with clearly superior clinical results, compared with other graft sources. However, autografts, especially 4-SHGs, showed similar or superior stability to irradiated allografts. Therefore, the graft source has a minimal effect on the clinical outcome, but it could have some effects on stability in single bundle transtibial PCL reconstruction.

Comparison of Tibial Tunnel Techniques in Posterior Cruciate Ligament Reconstruction: C-Arm Versus Anatomic Fovea Landmark

PCL fovea landmark technique might be an alternative method to the fluoroscopic imaging technique for locating the anatomic tibial tunnel during trans-tibial PCL reconstruction. Tibial insertion of the posterior cruciate ligament (PCL) is in the posterior half of the PCL fovea, or that the center of the PCL working fibers was 7 mm anterior to the posterior cortex. Intraoperative fluoroscopic images are usually used for the creation of the tibial tunnel during trans-tibial PCL reconstruction. However, intraoperative fluoroscopic identification of the tibial insertion area of the PCL is often impaired by tibial rotation and overlapping anatomic structures. Therefore, the definition of reliable, arthroscopically identificable anatomic landmarks would be of great value for proper positioning of the tibial guide pin in arthroscopic trans-tibial PCL reconstruction. During our trans-tibial PCL reconstruction, a trans-septal portal is made just behind the PCL fibers and the margin of the PCL fovea can be palpated with the tip of the tibial guide. The purpose of this study was to evaluate the accuracy of the posterior cruciate ligament (PCL) fovea landmark against conventional fluoroscopic pin placement retrospectively using three-dimensional computed tomography (3D CT). Our hypothesis was that accurate tibial tunnel preparation would be possible without intraoperative fluoroscopic imaging using reliable anatomic landmarks of the PCL fovea. This retrospective comparison focused on the tibial tunnel locations determined in consecutive 26 patients using fluoroscopic imaging technique (group I) and in consecutive 23 patients using the PCL fovea landmark technique without the help of the fluoroscopy (group II) for the tibial tunnel formation. The 3D surface modeled tomography (CT) images that appropriately located the position of PCL fovea on the tibial plateau were used. Ratios between total length of the fovea and length of the tunnel center from the medial border (coronal) and posterior edge (sagittal) were evaluated. The ratios between sagittal tunnel length and total sagittal length for groups I and II were 35.4 ± 12.2 % and 44.1 ± 23.1 %, respectively (p=0.07). The ratios between the coronal tunnel lengths and total coronal lengths for groups I and II were 47.3 ± 9.2 % and 57.3 ± 18.1 %, respectively: group II showed more laterally positioned tibial tunnel than did group I (p=0.03). More laterally located tibial tunnel was produced using a PCL fovea landmark technique. However, the differences in centers were small and probably not clinically relevant. Therefore, PCL fovea landmark technique might be an alternative method to the fluoroscopic imaging technique for locating the anatomic tibial tunnel during trans-tibial PCL reconstruction.

All-Anterior Approach for Arthroscopic Posterior Cruciate Ligament Reconstruction With Remnant Preservation

We describe the all-anterior approach for arthroscopic posterior cruciate ligament (PCL) reconstruction with remnant preservation. In this technique, PCL is reconstructed through 3 anterior portals: anterolateral portal, anteromedial portal, and inferior anterolateral portal, whereas the PCL remnant is preserved with great possibility. With the PCL elevator and wire catcher (Smith & Nephew), a self-made wire loop is introduced into the joint through the tibial tunnel, and is used to pass the graft in an all-inside-out fashion. In the transtibial PCL reconstruction technique, posterior portals are routinely adopted and the PCL remnant is often removed for good vision and adequate operative space, which can prolong surgery time and increase the potential risk of iatrogenic injury. In comparison, this technique not only simplifies the surgical procedure and reduces surgical trauma, but also preserves the remnant for our patients.