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Address correspondence to Sudeep Kumar, M.B.B.S., M.S., Department of Orthopaedics, AIIMS-Patna, 101, Type 5, Block 1, AIIMS Residential Complex, Patna, Bihar, India, 801105.
To evaluate the accuracy in the femoral and tibial tunnel placement after the use of fluoroscopy along with an indigenously designed grid method to assist in arthroscopic anterior cruciate ligament reconstruction as compared with the tunnel placement without using them and to validate the findings with computed tomography scan performed postoperatively along with assessing the functional outcome at a minimum of 3 years of follow-up.
Methods
This was a prospective study conducted on patients who underwent primary anterior cruciate ligament reconstruction. Patients were included and segregated into a nonfluoroscopy (group B) and a fluoroscopy group (group A), and both had postoperative computed tomography scans so that femoral and tibial tunnel position could be evaluated. Scheduled follow-up occurred 3, 6, 12, 24, and 36 months’ postoperatively. Patients were evaluated objectively with the Lachman test, measurement of range of motion, and functional outcome using patient-reported outcome measures, i.e., Tegner Lysholm Knee score, Knee injury and Osteoarthritis Outcome Score, and International Knee Documentation Committee subjective knee score.
Results
A total of 113 subjects were included. There were 53 in group A and 60 in group B. The average location of femoral tunnel showed significant differences between the 2 groups. However, the variability in femoral tunnel location was significantly lower in group A as compared with group B for proximal–distal planes only. The average location of the tibial tunnel as per the grid of Bernard et al. showed significant differences in both the planes. The variability in tibial tunnel was greater in the medial–lateral plane as compared with the anterior–posterior plane. There was a statistically significant difference in mean value of the 3 scores among the 2 groups. The variability of the scores was greater in group B as compared with group A. None of the patient was reported as a failure.
Conclusions
The results of our study suggests that fluoroscopy-guided positioning using a grid technique increases the accuracy of anterior cruciate ligament tunnel positioning with decreased variability and is associated with better patient-reported outcomes 3 years after surgery compared with tunnel positioning using landmarks.
Level of Evidence
Level II, prospective, comparative therapeutic trial.
Arthroscopic anterior cruciate ligament reconstruction (ACLR) surgery, being one of the most commonly performed knee surgeries, has an average success rate of 90% as far as individual satisfaction and restoration of joint stability are concerned.
The prime objective of an ACLR is to restore joint biomechanics to obtain a stable joint with full range of motion and prevention of secondary cartilage and meniscal lesions.
Among various causes responsible for graft failure, inaccurate tunnel placement is assumed to be one of the most important intraoperative variables and is directly influenced by the operating surgeon.
Of late, much importance is being put on placing the anterior cruciate ligament (ACL) graft in a more anatomical location on the tibia and femur, thereby having graft in a more horizontal orientation, which is believed to provide better rotational and translational stability; in addition the rate of atraumatic graft rupture is lower after anatomical ACLR.
Anatomical anterior cruciate ligament reconstruction (ACLR) results in fewer rates of atraumatic graft rupture, and higher rates of rotatory knee stability: A meta-analysis.
To achieve an anatomical ACLR, the surgeon has to take reference of various arthroscopic and radiologic landmarks. Anatomic aids like femoral ACL footprint, residents ridge, and lateral bifurcate ridge undergo interindividual variability or are influenced by delay in injury and surgery.
Among these, intraoperative fluoroscopy has been proposed as a feasible method to improve the accuracy of guidewire placement, and its role in reducing variability in tunnel position is already documented.
The purpose of this study is to evaluate the accuracy in femoral and tibial tunnel placement after use of fluoroscopy along with an indigenously designed grid method to assist in ACLR as compared with tunnel placement without using these and to validate the findings with computed tomography (CT) scanning done postoperatively along with assessing the functional outcome at a minimum of 3 years of follow-up. We hypothesized that intraoperative fluoroscopy and the indigenously designed grid method would allow accurate anatomical tunnel positioning during ACLR and would lead to better functional outcome as reported by various patient-reported outcome (PRO) measures.
Methods
This was an institute-based prospective study conducted on patients who underwent primary ACLR using quadruple looped hamstring autograft (semitendinosus and gracilis) between June 2016 and January 2019 in the Department of Orthopaedics. This research was approved by the institutional research board at the All India Institute of Medical Sciences Patna (IEC/AIIMS/PAT/116/2016).
In this study, we included patients aged between 18 and 45 years and with a confirmed diagnosis of ACL injury following clinicoradiologic evaluation with a minimum of 3 years of follow-up. The exclusion criteria included bilateral ACL tear, meniscal injury, associated ligament injury, such as medial collateral ligament, lateral collateral ligament, posterior cruciate ligament, or injury involving “posterolateral corner,” previous history of ACL repair or reconstruction, and those who refused to participate in the study. All included patients in the study provided written and informed consent.
All patients underwent ACLR performed by the senior author S.K. using quadruple looped hamstring autograft (semitendinosus and gracilis). Patients who underwent the procedure with the indigenously designed grid and intraoperatively fluoroscopy constituted group A, whereas patients who underwent the procedure without fluoroscopy constituted group B. It is important to emphasize that all patients in the nonfluoroscopy group underwent surgery before the first surgery in the fluoroscopy group.
Data obtained from both the groups during the study included demographic data, 3-dimensional CT position of femoral tunnel in anteroposterior and proximal–distal planes, tibial tunnel in anteroposterior and mediolateral planes expressed in percentage, and PROs, measured using the Tegner Lysholm Knee (TLK) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) subjective knee score, measured at 3, 6, 12, 24, and 36 months. The 36-month results were used to compare the groups. All statistical calculations were made using Statistical Package for the Social Sciences (SPSS), version 21.0 (IBM Corp., Armonk, NY). The primary outcome in our study was to compare the variability of tunnel placement in both groups.
A surgical team headed by senior author S.K. performed all the surgeries. Diagnostic arthroscopy was performed and associated injury to meniscus or articular cartilage was noted. Ipsilateral semitendinosus and gracilis graft were harvested using longitudinal incision over “anteromedial” aspect of proximal tibia; the graft was prepared over a graft-preparation board and a FiberWire (Arthrex, Largo, FL) suture was used for preparing the tendon in all the cases. Quadrupled hamstring (semitendinosus and gracilis) was used in all the patients. The prepared tendon was sized, measurements noted, and graft pretensioned with a tensioning device over the graft preparation board.
In group B, through the standard anteromedial portal, a Beath pin was placed at the center of the femoral ACL footprint, keeping in mind the remnants of the native ACL. Similarly, the anterior horn of lateral meniscus and tibial end ACL remnant were used as references for tibia tunnel placement. In group A, we used the surgical technique as described by Kumar et al.
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.
for accurate positioning of femoral and tibial tunnel using the indigenously made grid on a transparency sheet and C-arm. True lateral image of the knee is obtained intraoperatively and the indigenously designed grid containing 20 × 20 squares equidistant and an equal size of 5 mm on a transparent sheet is superimposed on the C-arm image by floor assistant. It is aligned on the intercondylar ridge and along the anteroposterior width of the lateral femoral condyle for femur. For the tibia, it is aligned over the proximal aspect along its maximum width in the anteroposterior direction (Figs 1 and 2).
Fig 1Intraoperative fluoroscopy image of lateral view of the right knee with the superimposed grid of Bernard et al.
Validation of a new technique to determine midbundle femoral tunnel position in anterior cruciate ligament reconstruction using 3-dimensional computed tomography analysis.
Validation of a new technique to determine midbundle femoral tunnel position in anterior cruciate ligament reconstruction using 3-dimensional computed tomography analysis.
). This image intensifier–guided method usually adds about 8 to 10 minutes’ more duration to the surgical time. In all the cases, femoral tunnels were made using the anterior cruciate ligament portal. Cortical suspensory fixation with adjustable loop ENDOBUTTON (Smith & Nephew, Andover, MA) was used to fix the graft tendon to the femoral side, whereas aperture fixation with a bioabsorbable interference screw as appropriate to tunnel diameter was performed to fix the graft tendon to the tibial side in all the cases. The patient was made to stand with full weight-bearing from postoperative day 1 and start active knee mobilization along with quadriceps strengthening exercises. All patients followed similar standard hospital ACL rehabilitation protocol.
The 3D CT scan was performed on day 7 using a Siemens SOMATOM 256-slice CT scanner (Siemens, Munich, Germany) at 120 kv, mAs 256 in standard and bone algorithm with slice thickness of 1 mm. Three-dimensional reconstruction of the knee in the true lateral was made, and the proximal tibia, patella, and medial femoral condyle were removed so as to obtain an explicit view of the inner side of the lateral femoral condyle. With the image in true lateral, the indigenously designed transparency sheet with inbuilt grid was superimposed as described by Sirleo et al.,
Parameters were expressed in terms of percentage for “proximal–distal” and “anteroposterior” placement. For tibial tunnel position evaluation, the femur and patella were removed and image was placed such that tunnel could be viewed clearly and the center of tibia tunnel on the plateau was measured in “anteroposterior” and “medial–lateral” planes and expressed as a percentage (Fig 3 and 4) This assessment was performed by the senior author S.K. with aid from radiologist (M.D., radiodiagnosis) and the same author and team members (M.S., orthopaedics) followed the patients postoperatively.
Fig 3Postoperative 3-dimensional computed tomography of the lateral femoral condyle for evaluation of femoral tunnel position with the superimposed grid of Bernard et al.
Validation of a new technique to determine midbundle femoral tunnel position in anterior cruciate ligament reconstruction using 3-dimensional computed tomography analysis.
Fig 4Postoperative 3-dimensional computed tomography of proximal tibia for evaluation of tibia tunnel position with the superimposed grid of Bernard et al.
Scheduled follow-ups were at 3, 6, 12, 24, and 36 months’ postoperatively. Patients were evaluated objectively with the Lachman test, measurement of range of motion, and functional outcome, assessed using PRO measures, i.e., the TLK score, KOOS, and IKDC subjective knee score, all of which were validated.
The reliability, validity, and responsiveness of the Lysholm score and Tegner activity scale for anterior cruciate ligament injuries of the knee: 25 years later.
In our study, failure was defined as a complaint of instability from the patient with clinically grade 2 or more in the Lachman test and at least grade 2 in pivot shift test and/or rupture requiring a revision surgery.
Results
A total of 113 patients who had attended our outpatient clinic and fulfilled inclusion criteria were prospectively included into the study. A total of 53 consecutive patients who underwent ACLR using intraoperative fluoroscopy along with an indigenously designed grid constituted group A, whereas another 60 consecutive patients who underwent ACLR without using fluoroscopy intraoperatively constituted group B. None of the participants in either group was excluded from the study.
The demographic data are summarized in Table 1 and show no significant differences between the 2 groups. Table 2 summarizes the variables of the femoral tunnel location among the groups. The mean location of femoral tunnel center in group A, evaluated after 3-dimensional CT, was 29.66 ± 6.00% and 30.98 ± 4.36% in the “anteroposterior” and “proximal–distal planes,” respectively. Similarly in group B, the locations were 21.88 ± 5.35% and 42.22 ± 6.40% in the “anteroposterior” and “proximal–distal” planes, respectively. The average location of the femoral tunnel showed significant differences between the 2 groups, P < .001, in both measures. However, the variability in femoral tunnel location was significantly lower in group A as compared with group B for proximal–distal planes only.
Table 3 summarizes the coordinates of the tibial tunnel. In group A, the location of tibial tunnel center was 47.35 ± 2.75% and 41.34 ± 5.39% in the “medial–lateral” and “anteroposterior” planes, respectively. In group B, the location of tibial tunnel center was 45.95 ± 3.62% and 37.05 ± 4.57% in the “medial–lateral” and “anterioposterior” planes, respectively. The average location of the tibial tunnel as per the grid of Bernard et al. showed significant differences in both the planes, P < .05. The variability in tibial tunnel was greater in the medial–lateral plane as compared with the anteroposterior plane between the 2 groups.
Table 3Assessment of Tibial Tunnel Location Variability
Table 4 summarizes the PRO measures among the 2 groups at 36 months. In group A, the TLK, IKDC, and KOOS scores were 97.88 ± 1.35, 85.46 ± 1.78, and 96.43 ± 2.63, respectively. In group B, the TLK, IKDC, and KOOS scores were 86.88 ± 5.01, 68.78 ± 7.01, and 87.94 ± 7.62, respectively. There was statistically a significant difference in mean value of the 3 scores among the 2 groups, P < .001. The variability of the scores was greater in group B as compared with group A. None of the patients was reported as a failure in our study.
Table 4Assessment of Functional Outcome Among Groups A and B
Group
TLK Knee Score
IKDC Knee Score
KOOS
A
B
P Value
A
B
P Value
A
B
P Value
Mean
97.88
86.881
85.46
68.78
96.43
87.94
Max.
100
100
89.10
89.00
100
100
Min.
95
73
79.30
44.80
88.70
63.20
SD
1.35
5.01
<.001
1.78
7.01
.00
2.63
7.62
<.001
Range
5
27
9.80
44.20
11.30
36.80
IKDC, International Knee Documentation Committee; KOOS, Knee injury and osteoarthritis outcome score; SD, standard deviation; TLK, Tegner Lysholm.
The main finding of this study was that there was significant improvement in both the femoral and tibial tunnel position after the introduction of fluoroscopy in arthroscopic ACL reconstruction when compared with the nonfluoroscopy group. Second, intraoperative fluoroscopy assistance allowed the PRO measures to improve significantly and, lastly, there was also significant reduction in femoral tunnel variability especially in proximal–distal direction and sagittal plane tibia tunnel placement.
As the ideal location of femoral and tibial tunnel in ACL reconstruction is still contentious, and with numerous literature reports of variability in tunnel location irrespective of anatomical landmark used, there is growing interest in of the role of intraoperative fluoroscopy.
Excessive anteriorly placed femoral tunnel leads to high tension in the graft, which can restrict range of motion and eventually elongation or the ultimate failure of the graft.
Similarly, tibial tunnel placed >50% posteriorly along the tibial plateau can result in loss of flexion and a significant increase in the rupture rate as compared with the <50% group.
Anterior placement of the tibial tunnel can cause roof impingement in extension. Medial placement of tibial tunnel causes posterior cruciate ligament impingement.
Effect of the angle of the femoral and tibial tunnels in the coronal plane and incremental excision of the posterior cruciate ligament on tension of an anterior cruciate ligament graft: An in vitro study.
in their cadaveric study revealed that even the experienced surgeons find it difficult to distinctly identify the ACL attachments with arthroscopy technique. An audit of tunnel position after ACL reconstruction found that 65% of femoral tunnels and 59% of the tibial tunnels were malpositioned in the sagittal plane.
Our understanding of fluoroscopic-guided tunnel placement evaluated by CT is limited.
Among studies that evaluated effect of intraoperative fluoroscopy on tunnel positioning and validated the position with postoperative CT, Inderhaug et al.
investigated 112 cases of fluoroscopy-assisted ACL reconstruction and concluded that intraoperative fluoroscopy could determine the tunnel position more consistently and reliably. Kawakami et al.,
in their study, found the fluoroscopy group to have a femoral tunnel significantly closer to the “ideal” anatomic point. In addition, the timing of imaging after surgery is not standardized. We routinely got the CT scan done at day 7 after surgery. The radiation exposure for a CT of the knee is equivalent to 2 radiographs of the chest, which must be taken into consideration.
Our study has some limitations. We did not have an objective method to evaluate the rotational stability. Cost-effectiveness of using intraoperative fluoroscopy followed by postoperative 3D CT scan could not be ascertained. There was only one surgeon involved in the study. Because we did not perform a sample size calculation according to femoral tunnel position, there is a risk for a type II error.
Conclusions
The results of our study suggests that fluoroscopy-guided positioning using a grid technique increases the accuracy of ACL tunnel positioning with decreased variability and is associated with better PROs 3 years after surgery compared with tunnel positioning using landmarks.
Anatomical anterior cruciate ligament reconstruction (ACLR) results in fewer rates of atraumatic graft rupture, and higher rates of rotatory knee stability: A meta-analysis.
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.
Validation of a new technique to determine midbundle femoral tunnel position in anterior cruciate ligament reconstruction using 3-dimensional computed tomography analysis.
The reliability, validity, and responsiveness of the Lysholm score and Tegner activity scale for anterior cruciate ligament injuries of the knee: 25 years later.
Effect of the angle of the femoral and tibial tunnels in the coronal plane and incremental excision of the posterior cruciate ligament on tension of an anterior cruciate ligament graft: An in vitro study.
The authors report that they have no conflicts of interest in the authorship and publication of this article. Full ICMJE author disclosure forms are available for this article online, as supplementary material.
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