Anatomical placement of double femoral tunnels in anterior cruciate ligament reconstruction: anteromedial tunnel first or posterolateral tunnel first?

Reliability of measuring femoral tunnel aperture location after anterior cruciate ligament reconstruction: quadrant method versus anatomical coordinate axes method

BACKGROUND

The purpose was to quantitatively compare the reliability of the quadrant and ACA methods in identifying the position of the femoral tunnel aperture after ACL reconstruction (ACLR) using 3D-CT.

METHODS

This study included 90 patients (90 knees) who underwent primary single-bundle ACLR. 3D-CT was performed on each knee, and the femoral tunnels were evaluated twice each by two observers using both the quadrant and anatomical coordinate axes (ACA) methods. The data were analyzed statistically to determine the inter and intraobserver reliabilities using an intraclass correlation coefficient [ICC, excellent (>0.9), good (0.75-0.9), moderate (0.5-0.75), poor (<0.5)].

RESULTS

Regarding intraobserver comparisons, the ICCs of quadrant method (1st observer: excellent, 2nd observer: excellent) were better than ACA method (1st observer: good, 2nd observer: good) on Y-axis. Both methods showed good ICCs on X-axis. Regarding interobserver comparisons, the ICCs of the ACA method were better than those of the quadrant method on the X-axis. (1st measurement: moderate, 2nd measurement: good vs. 1st measurement: good, 2nd measurement: good) However, ICCs of quadrant method were better on the Y-axis. (1st measurement: excellent, 2nd measurement: excellent vs. 1st measurement: excellent, 2nd measurement: good).

CONCLUSION

For measuring the femoral tunnel aperture on 3D-CT after ACLR, the quadrant method showed better intraobserver and interobserver reliability on Y-axis, whereas the ACA method showed better interobserver reliability on the X-axis.

The incidence of tibial tunnel coalition is higher than femoral tunnel coalition in double-bundle anterior cruciate ligament reconstruction using hamstring autografts: A systematic review

INTRODUCTION

Intra-operative and postoperative coalition of tunnels may occur in double-bundle (DB) anterior cruciate ligament reconstruction (ACLR). However, the incidence and effect on clinical outcomes of tunnel coalition following primary DB ACLR using a hamstring autograft has yet be analyzed, and thus remains unknown. The objective of this systematic review was to identify the incidence of tunnel coalition upon DB ACLR using hamstring autografts and to elucidate any clinical outcomes and/or complications that tunnel coalition may have postoperatively.

HYPOTHESIS

The incidence of tunnel coalition would increase in respect to time from the index surgery, and that tunnel coalition would be related to poorer clinical outcomes compared to non-coalition cases.

METHODS

Three databases (PubMed, EMBASE, Cochrane Library) were searched in accordance with PRISMA and R-AMSTAR guidelines on June 15, 2020. Relevant studies were screened in duplicate and data regarding patient demographics, incidence of femoral and tibial tunnel coalition, and outcomes were extracted. Coalition rate was also compared between follow up at 1 month or less defined as "shorter-term", and 6 months or greater as "longer-term". Coalition is defined as the missing of a bony bridge between the two tunnels.

RESULTS

Thirty-six studies examining 1,574 patients, mean age 29.1 years, were included in this study. 29 studies (1,110 knees) reported the incidence of femoral coalition with a pooled rate of coalition of 8% (95% CI=4-12%). 28 studies (1,129 knees) reported an incidence of tibial coalition with a pooled rate of coalition of 21% (95% CI=13-30%). The incidence of tibial coalition was significantly higher than the incidence of femoral coalition across 21 comparative studies (OR=3.37, 95% CI=1.41-8.09, p=0.0065). Only two studies (111 knees) compared tunnel coalition and non-coalition groups for clinical outcome and no significant differences were observed with regards to Lysholm score, Tegner activity scale, and knee laxity measured with a KT-1000 arthrometer.

DISCUSSION

The rate of tibial tunnel coalition in DB ACLR is higher than femoral tunnel coalition, particularly at longer-term follow-up. Despite the higher radiographic evidence of coalition, the clinical effects of such remain to be ascertained, and further comparative studies are required to facilitate this understanding.

LEVEL OF EVIDENCE

IV, systematic review.

Influence of Age on Signal Intensity of Magnetic Resonance Imaging and Clinical Outcomes in Double-Bundle Anterior Cruciate Ligament Reconstruction: Comparisons Among Different Age Groups

BACKGROUND

Thus far, the clinical results of anterior cruciate ligament (ACL) reconstruction have been observed to be comparable between young and older patients. In contrast, age-related changes in the structural and mechanical properties of tendons used for autografts have been described. However, age-related changes associated with graft maturation remain poorly understood.

HYPOTHESES

The hypotheses of this study were that (1) clinical outcomes after ACL reconstruction would be comparable between younger and relatively older patients and (2) younger patients would show lower signal intensity changes on magnetic resonance imaging scans indicative of graft maturation that would be better than that in relatively older patients.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We retrospectively evaluated 236 patients who underwent double-bundle ACL reconstruction via the outside-in technique using hamstring autograft between January 2012 and December 2015. The patients were categorized by age into 3 groups: <20 years old, 20 to 39 years old, and ≥40 years old. Clinical outcomes were evaluated using the subjective International Knee Documentation Committee (IKDC) score, Tegner activity scale, Lysholm score, and objective assessment of joint laxity 24 months after surgery. In addition, graft maturation was evaluated using magnetic resonance imaging-derived measures of the signal intensity ratio (SIR) at 3, 6, 12, and 24 months postoperatively. Clinical outcomes and graft maturation were compared among the 3 groups.

RESULTS

The SIR of both bundles increased from 3 months to 12 months and decreased by 24 months, showing the same tendency in all groups. No significant difference was found in the SIR among the 3 groups at any time point (P > .05). The IKDC score was significantly lower in the ≥40-year group than in the <20-year group (P < .01). In contrast, no significant differences were noted in other clinical outcomes.

CONCLUSION

Patients aged ≥40 years exhibited lower IKDC scores compared with younger patients, although the results of graft maturation were comparable.

Chronological Changes in Anterior Knee Stability after Anatomical Anterior Cruciate Ligament Reconstruction Using Bone-Patellar Tendon-Bone and Hamstring Grafts

The clinical outcomes of anterior cruciate ligament (ACL) reconstruction are typically evaluated at specific time points only. This study aimed to characterize the chronological changes in anterior knee stability after anatomical ACL reconstruction and to compare the anterior knee stability achieved with bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) grafts. A total of 59 patients underwent anatomical rectangular tunnel ACL reconstruction using the BPTB graft and 23 patients underwent anatomical double-bundle ACL reconstruction using the HT graft. Anterior knee stability was quantitatively assessed using the KneeLax 3 arthrometer at 6 months, 1 year, and 2 years after surgery using side-to-side differences. The values for anterior knee stability using the BPTB graft were 0.3 mm after 6 months, 0.2 mm after 1 year, and 0.2 mm after 2 years, and no significant differences were observed during the postoperative study period. Meanwhile, the values for anterior knee stability using the HT graft were -0.3 mm after 6 months, 0.5 mm after 1 year, and 1.2 mm after 2 years, and anterior knee stability decreased chronologically from 6 months up to 2 years. Regarding anterior stability, the HT graft showed significant laxity compared with the BPTB graft only after 2 years. No chronological changes in anterior stability were observed from 6 months up to 2 years after ACL reconstruction using the BPTB graft, whereas anterior laxity developed during the same period after ACL reconstruction using the HT graft. This is a Level IV, therapeutic case series study.

Superior graft maturation after anatomical double-bundle anterior cruciate ligament reconstruction using the transtibial drilling technique compared to the transportal technique

PURPOSE

To evaluate and compare the femoral tunnel aperture position, graft bending angle and the magnetic resonance imaging (MRI) graft signal intensity after anatomical double-bundle anterior cruciate ligament (ACL) reconstruction between transtibial and transportal drilling techniques of the femoral tunnel.

METHODS

Eighty-seven patients who underwent anatomic double-bundle ACL reconstruction with hamstring tendon autograft between January 2012 and December 2014 were included in this retrospective study. Forty-one patients underwent reconstruction using a transportal technique (TP group) and 46 patients underwent reconstruction using a transtibial technique (TT group). The anteromedial (AM) femoral aperture position and the graft bending angle were assessed using transparent three-dimensional CT 2 weeks postoperatively. MRI assessment was performed with proton density-weighted images in an oblique coronal plane 6 and 12 months postoperatively. Signal/noise quotient was calculated for two specific graft sites (femoral tunnel site and mid-substance site). Femoral aperture position, the graft bending angle and signal/noise quotient were compared between the TP and TT groups.

RESULTS

There was no significant difference in the aperture position between the two groups. The graft bending angle of the AM tunnel in the axial plane was significantly greater in the TP group (p < 0.001). On the other hand, the TP group had a significantly more acute angle in the coronal plane (p < 0.001). There was no significant difference at either site in the signal/noise quotient of the graft between the two groups at 6 months. However, the TT group had a lower signal/noise quotient at 12 months at both sites (femoral aperture: p = 0.04, mid-substance: p = 0.004).

CONCLUSION

There was a significant difference in signal/noise quotient between the two drilling techniques 12 months postoperatively. There was no significant difference in femoral tunnel aperture position between the two groups. However, graft bending angle at the femoral tunnel aperture was significantly different between the two groups, indicating the possibility that graft bending angle is a factor that influences graft maturation. This indicates that the TT technique has an advantage over the TP technique in terms of graft maturation.

The Relationship Between ACL Femoral Tunnel Position and Postoperative MRI Signal Intensity

BACKGROUND

The purpose of this study was to find the ideal femoral tunnel position in single-bundle anterior cruciate ligament (ACL) reconstruction using three-dimensional computed tomography (3D-CT) by comparing clinical scores, stability of the knee joint, and graft signal intensity on follow-up magnetic resonance imaging (MRI). We hypothesized that positioning the femoral tunnel near the anteromedial bundle or center would lead to better results in terms of clinical outcomes and graft signal intensity on follow-up MRI than would positioning the tunnel near the posterolateral bundle.

METHODS

Two hundred patients underwent arthroscopic single-bundle ACL reconstruction with a soft-tissue graft; all patients had the same surgeon, surgical technique (anteromedial transportal technique), and rehabilitation protocol. Each patient underwent 3D-CT within 1 week after the operation and MRI at 1 year after the operation. Outcomes were evaluated in terms of clinical scores and the stability of the knee joint. We classified patients into three groups based on the femoral tunnel position: the anteromedial position group, the posterolateral position group, and the center position group. We evaluated graft signal intensity on follow-up MRI.

RESULTS

This study included 77 patients: 25 patients in the anteromedial position group, 15 patients in the posterolateral position group, and 33 patients in the center position group. Four patients had an eccentric tunnel position and were excluded. The 3 groups did not differ significantly (p > 0.05) in preoperative demographic characteristics. There were no significant differences (p > 0.05) between groups in clinical outcomes. However, patients in the anteromedial position group and in the center position group had better graft signal intensity on follow-up MRI than those in the posterolateral position group.

CONCLUSIONS

Positioning the femoral tunnel near the anteromedial bundle and center led to better graft signal intensity on follow-up MRI in anatomic single-bundle ACL reconstruction than did positioning the femoral tunnel near the posterolateral bundle. There were no differences in clinical scores or stability of the knee joint among the three groups.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Current use of navigation system in ACL surgery: a historical review

PURPOSE

The present review aims to analyse the available literature regarding the use of navigation systems in ACL reconstructive surgery underling the evolution during the years.

METHODS

A research of indexed scientific papers was performed on PubMed and Cochrane Library database. The research was performed in December 2015 with no publication year restriction. Only English-written papers and related to the terms ACL, NAVIGATION, CAOS and CAS were considered. Two reviewers independently selected only those manuscripts that presented at least the application of navigation system for ACL reconstructive surgery.

RESULTS

One hundred and forty-six of 394 articles were finally selected. In this analysis, it was possible to review the main uses of navigation system in ACL surgery including tunnel positioning for primary and revision surgery and kinematic assessment of knee laxity before and after different surgical procedures. In the early years, until 2006, navigation system was mainly used to improve tunnel positioning, but since the last decade, this tool has been principally used for kinematics evaluation. Increased accuracy of tunnel placement was observed using navigation surgery, especially, regarding femoral, 42 of 146 articles used navigation to guide tunnel positioning. During the following years, 82 of 146 articles have used navigation system to evaluate intraoperative knee kinematic. In particular, the importance of controlling rotatory laxity to achieve better surgical outcomes has been underlined.

CONLUSIONS

Several applications have been described and despite the contribution of navigation systems, its potential uses and theoretical advantages, there are still controversies about its clinical benefit. The present papers summarize the most relevant studies that have used navigation system in ACL reconstruction. In particular, the analysis identified four main applications of the navigation systems during ACL reconstructive surgery have been identified: (1) technical assistance for tunnel placement; (2) improvement in knowledge of the kinematic behaviour of ACL and other structures; (3) comparison of effectiveness of different surgical techniques in controlling laxities; (4) navigation system performance to improve the outcomes of ACL reconstruction and cost-effectiveness.

LEVEL OF EVIDENCE

IV.

Anatomic Placement of the Femoral Tunnels in Double-Bundle Anterior Cruciate Ligament Reconstruction Correlates With Improved Graft Maturation and Clinical Outcomes

PURPOSE

To compare maturation of reconstructed graft on second-look arthroscopy and clinical outcomes between 2 groups: the provisional anatomic (PA) group, with both the anteromedial (AM) and posterolateral (PL) femoral tunnels in their anatomic location, and the nonanatomic (NA) group, with either 1 of the 2 femoral tunnels beyond its anatomic location after double-bundle anterior cruciate ligament reconstruction.

METHODS

We enrolled 154 patients who underwent 3-dimensional computed tomography scanning and second-look arthroscopy after double-bundle anterior cruciate ligament reconstruction. All of the patients were divided into the PA and NA groups according to the femoral tunnel position determined by the quadrant method. Graft maturation was evaluated with 3 subsections, including integrity, tension, and synovial coverage with revascularization, on second-look arthroscopy. We also compared Lachman test, pivot-shift test, KT-2000 (MEDmetric, San Diego, CA), and International Knee Documentation Committee grades at the last follow-up.

RESULTS

Of the 154 patients, 88 were classified as the PA group and 66 as the NA group by the quadrant method. A difference existed between groups for the AM tunnel position but not for the PL tunnel position. The PA group showed a higher graft maturation score (P < .001 for all comparisons) and better results according to the International Knee Documentation Committee knee rating, Lachman test, pivot-shift test, and KT-2000 assessment (P < .001 for all comparisons).

CONCLUSIONS

The PA group with anatomic femoral tunnel placement showed a higher graft maturation score on second-look arthroscopy, along with better clinical outcomes, than the NA group. There was a significant difference in the AM femoral tunnel position but not in the PL tunnel position between the 2 groups.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Intercondylar notch size influences cyclops formation after anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to investigate the incidence of cyclops lesions and its relationship with the cross-sectional area of the intercondylar notch.

METHODS

For this study, 55 patients (24 male and 31 female) underwent follow-up arthroscopy after bi-socket anterior cruciate ligament reconstruction with hamstring tendon grafts were included. All patients underwent magnetic resonance imaging measurements of intercondylar notch dimensions. We compared the femoral intercondylar notch sizes and bone tunnel sizes between knees with cyclops lesions (cyclops group) and those without cyclops lesions (no-cyclops group). The mean percentage of the tunnel size to the cross-sectional area of the femoral intercondylar notch was also compared between the groups. The median follow-up duration was 3.8 years.

RESULTS

Cyclops lesions were found in 15 of the 55 knees (27.3 %) on second-look arthroscopy (cyclops group). Only 6 of the 55 knees (10.9 %) had extension loss (cyclops syndrome). The cyclops group included 3 men and 12 women. The two groups showed a statistical difference in sex variation (P = 0.04). No significant differences were found in the femoral and tibial tunnel sizes between the two groups. The cross-sectional area of the femoral intercondylar notch was significantly smaller in the cyclops group (251.7 ± 63.2 mm(2)) than in the no-cyclops group (335.6 ± 77.6 mm(2)) (P < 0.001). The percentage of the total femoral tunnel size to the cross-sectional area of the femoral intercondylar notch was significantly higher in the cyclops group (18.6 ± 5.3 %) than in the no-cyclops group (13.2 ± 3.6 %) (P = 0.02).

CONCLUSIONS

A smaller intercondylar notch size may be a potential risk factor for cyclops lesion formation.

LEVEL OF EVIDENCE

Case-control study, Level IV.

Influences of knee flexion angle and portal position on the location of femoral tunnel outlet in anterior cruciate ligament reconstruction with anteromedial portal technique

PURPOSE

To evaluate the influences of knee flexion angle and portal position on the location of femoral tunnel outlet in anterior cruciate ligament (ACL) reconstruction with the anteromedial (AM) portal technique.

METHODS

We recruited 6 volunteers with 12 normal knees. Each knee was flexed 120° or 135° and scanned with an open MRI. A 3D knee model was created. Virtual femoral tunnels were created on the footprint of the AM bundle and the posterolateral (PL) bundle of the ACL from three arthroscopic portals: the standard AM portal, the far medial and low portal, and the far medial and high (FMH) portal. The location of the femoral tunnel outlet was evaluated by comparing to the dissected cadaveric knee.

RESULTS

Both increased flexion angle and lowering the drilling portal have a similar influence on the femoral tunnel outlet by moving them anterior and distally. Medialization of the portal moves them posteriorly and distally. PL tunnels created on the 120° knee model are more likely to be located under the lateral head of the gastrocnemius especially when they are drilled through the AM or FMH portals.

CONCLUSION

If the femoral tunnel outlet is located under the soft tissue such as gastrocnemius attachment, suspension fixation devices may lapse into fixation failure by sitting on the soft tissue rather than the cortex bone surface. It is more desirable to drill in 135° knee flexion rather than 120°, and through a lower portal, to avoid creating the femoral tunnel outlet under soft tissues.

Treatment of Anterior Cruciate Ligament Injuries by Major League Soccer Team Physicians

Background:

The treatment and rehabilitation procedures of anterior cruciate ligament (ACL) injuries in elite soccer players are controversial. Points of debate include surgical timing, technique, graft choice, rehabilitation, and return-to-sport criteria and timing.

Purpose:

To identify practice preferences among current Major League Soccer (MLS) team orthopaedic surgeons for ACL injuries.

Study Design:

Cross-sectional study; Level of evidence, 4.

Methods:

The survey was administered at the MLS team physician annual meeting in January 2013. At least 1 orthopaedic surgeon representative from each of the 19 clubs (16 from the United States, 3 from Canada) was in attendance. Teams with more than 1 affiliated orthopaedic surgeon were given an additional survey to be completed either at the meeting or returned via e-mail. Descriptive statistics, Wilcoxon Mann-Whitney (return-to-play parameters, running, and ball drills), and Fisher exact tests (graft selection, bracing, continuous passive motion) were applied to the various data sets from the survey responses.

Results:

A 100% survey participation rate was achieved (22 team orthopaedic surgeons representing 19 MLS teams). A single-incision, arthroscopically assisted, single-bundle reconstruction was the most common technique (91%). Surgeons were split regarding femoral tunnel drilling (50% transtibial, 46% accessory medial). Autograft bone–patellar tendon–bone (BPTB) was the most common preferred graft choice (68%). The biggest concerns about BPTB autograft and hamstring autograft were anterior knee pain (76%) and hamstring weakness (46%), respectively. Most surgeons did not recommend postoperative continuous passive motion (64%) or functional bracing (68%). Most surgeons permitted return to sport without restrictions at 6 to 8 months following surgery (82%). Surgeons who routinely used functional bracing after ACL surgery more frequently used hamstring autograft than those who used BPTB autograft (P = .04).

Conclusion:

This article successfully describes current management of ACL injuries among MLS team orthopaedic surgeons. The preference for single-bundle BPTB autograft is similar to published data in the National Football League and National Basketball Association.

Clinical outcome of anatomic double-bundle ACL reconstruction and 3D CT model-based validation of femoral socket aperture position

PURPOSE

The purpose of this study was to evaluate the clinical results of anatomic double-bundle (DB) anterior cruciate ligament (ACL) reconstruction in which anatomic position of femoral socket apertures was validated using three-dimensional (3D) computed tomography (CT) modelling.

METHODS

Anatomic DB ACL reconstructions with hamstring autografts were performed in 34 patients. Two femoral sockets were created through a far anteromedial (AM) portal behind the lateral intercondylar ridge with the assistance of intraoperative 3D fluoroscopic navigation. Femoral tunnel aperture positioning was investigated postoperatively using 3D CT images in all patients. Clinical results were also evaluated subjectively and objectively at least up to 2 years.

RESULTS

Measurement of the AM and the posterolateral (PL) femoral socket locations on the 3D CT images using the quadrant method showed that the centre of the AM socket aperture was located at a depth of 21.0 ± 4.1% and a height of 30.5 ± 9.3% and that of the PL socket aperture was located at a depth of 31.3 ± 5.8% and a height of 57.2 ± 7.7%. The femoral socket locations were considered as anatomic in accordance with previous cadaveric studies examining the positions of ACL femoral insertion site. Subjectively, the mean Lysholm score was 96.9 ± 4.0 points. According to IKDC final objective scores, 26 knees (76%) were objectively graded as normal, 8 (24%) as nearly normal, and 0 (0%) as abnormal or severely abnormal. Postoperative side-to-side anterior translation measured with a KT-2000 arthrometer averaged 0.7 ± 1.2 mm.

CONCLUSIONS

DB ACL reconstructions in which femoral socket apertures were validated anatomically using 3D CT provided satisfactory short-term results.

LEVEL OF EVIDENCE

Case series, Level IV.

Remnant-preserving anterior cruciate ligament reconstruction using a three-dimensional fluoroscopic navigation system

INTRODUCTION

Recently, remnant-preserving anterior cruciate ligament (ACL) reconstruction has been increasingly performed to achieve revascularization, cell proliferation, and recovery of high-quality proprioception. However, poor arthroscopic visualization makes accurate socket placement during remnant-preserving ACL reconstruction difficult. This study describes a surgical technique used to create an anatomical femoral socket with a three-dimensional (3D) fluoroscopy based navigation system during technically demanding remnant-preserving ACL reconstruction.

SURGICAL TECHNIQUE

After a reference frame was attached to the femur, an intraoperative image of the distal femur was obtained, transferred to the navigation system and reconstructed into a 3D image. A navigation computer helped the surgeon visualize the entire lateral wall of the femoral notch and lateral intercondylar ridge, even when the remnant of the ruptured ACL impeded arthroscopic visualization of the bone surface. When a guide was placed, the virtual femoral tunnel overlapped the reconstructed 3D image in real time; therefore, only minimal soft tissue debridement was required.

MATERIALS AND METHODS

We treated 47 patients with remnant-preserving ACL reconstruction using this system. The center of the femoral socket aperture was calculated according to the quadrant technique using 3D computed tomography imaging.

RESULTS

The femoral socket locations were considered to be an anatomical footprint in accordance with previous cadaveric studies.

CONCLUSIONS

The 3D fluoroscopy-based navigation can assist surgeons in creating anatomical femoral sockets during remnant-preserving ACL reconstruction.

Transparent 3-dimensional CT in evaluation of femoral bone tunnel communication after ACL double-bundle reconstruction: comparison between outside-in and transportal technique

PURPOSE

The purpose of this study is to assess the incidence of post-operative femoral bone tunnel communication after anterior cruciate ligament double-bundle reconstruction (ACL-DBR) with two drilling techniques by transparent 3-dimensional computed tomography (CT) and elucidate the factors associated with post-operative femoral bone tunnel communication.

METHODS

Fifty-five patients underwent ACL-DBR using outside-in technique (Group A, 25 patients) and transportal technique (Group B, 30 patients) for the drilling of femoral tunnel. CT was taken at 1 week and 6 months post-operatively. The femoral and tibial bone tunnel orientation, position, the divergency and the distance of bone bridge between the tunnels were measured using reconstructed CT images. In order to identify the factors related to post-operative femoral bone tunnel communication, patients were divided into two groups depending on whether femoral bone tunnels communicated (Group F-C) or remained (Group F-R) at 6 months post-operatively.

RESULTS

Femoral bone tunnels in Group B were orientated horizontally and dorsally compared to those in Group A. Tunnel divergency between two femoral tunnels was greater in Group A (11.7°) than in Group B (10.0°). Average distance of bone bridge at 1 week post-operatively was 1.8 mm in Group A and 1.7 mm in Group B (n.s.). Post-operative femoral bone tunnel communication occurred in 16 patients (64 %) in Group A and in 18 patients (60 %) in Group B at 6 months after ACL-DBR, respectively (n.s.). Regarding tibial tunnels, there were no significant differences in tunnel orientation, position, divergency and incidence of post-operative tibial tunnel communication between Groups A and B. Mean distance of femoral bone bridge at 1 week in Group F-R (2.5 mm) was significantly greater than in Group F-C (1.3 mm) (p < 0.001).

CONCLUSIONS

There was no significant difference in the incidence of post-operative femoral tunnel communication between two techniques. To avoid post-operative femoral tunnel bone communication, more than 2 mm distance of bone bridge at surgery is recommended.

Eccentric femoral tunnel widening in anatomic anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to retrospectively evaluate femoral tunnel widening (TW) and migration of the femoral tunnel aperture after anatomic anterior cruciate ligament (ACL) reconstructions with hamstring grafts and bone-patellar tendon-bone (BPTB) grafts.

METHODS

Of the 105 consecutive patients who underwent ACL reconstruction, the 52 patients who underwent isolated ACL reconstruction and in whom tunnel measurement could be obtained by computed tomography were included in this study. In 26 patients, double-bundle reconstruction (DBR) of the ACL using hamstring tendons was performed. These patients were compared with 26 patients in whom rectangular tunnel ACL reconstruction using BPTB grafts (BPTBR) was performed. Femoral tunnel aperture positioning and TW were investigated postoperatively using 3-dimensional computed tomographic images, which were performed a week and a year after surgery in all patients.

RESULTS

In DBR, the average diameter of the anteromedial (AM) femoral tunnel increased by 34.0% in the horizontal direction and 28.2% in the vertical direction, whereas that of the posterolateral (PL) femoral tunnel increased by 58.2% and 73.4%, respectively, at 1 year after surgery compared with 1 week after surgery. The percentage TW value of the PL tunnel was significantly greater than that of the AM tunnel. In BPTBR, the average diameter increased by 22.0% and 17.1%, respectively. The percentage TW value of the PL tunnel in DBR was significantly greater than that of the femoral tunnel in BPTBR. Each tunnel aperture migrated distally ("shallow") in the horizontal direction and high in the vertical direction. AM and PL tunnel apertures in DBR migrated in the vertical direction significantly more than they did in BPTBR. No significant differences between the 2 groups were found in clinical outcomes.

CONCLUSIONS

The femoral PL tunnel aperture in DBR showed significantly more widening than did the AM tunnel aperture in DBR and the femoral tunnel aperture in BPTBR. Also, greater migration of the femoral tunnel aperture in the vertical direction because of TW was observed in DBR than in BPTBR.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Far anteromedial portal technique for posterolateral femoral tunnel drilling in anatomic double-bundle anterior cruciate ligament reconstruction: a cadaveric study

PURPOSE

To identify the relationship between knee flexion angle and femoral tunnel length, as well as the exit points of guidewires, when using a far anteromedial portal technique for posterolateral femoral tunnel drilling in double-bundle anterior cruciate ligament reconstruction.

METHODS

Using the far anteromedial portal technique in 8 cadaveric knees, femoral tunnel drilling for the posterolateral bundle was performed at 3 knee flexion angles: 90°, 110° and 130°. We measured the femoral tunnel length and the distances from each guidewire to the closest relevant structures.

RESULTS

The mean tunnel length at 90° knee flexion (25.8 ± 1.8 mm) was significantly shorter than the length at 110° and 130° knee flexion (32.1 ± 2.6 and 33.1 ± 2.5 mm, respectively). The average distance between the exit point of the guidewire and the posterior articular cartilage of the lateral femoral condyle was the shortest at 90° knee flexion (3.3 ± 2.2 mm). The distance between the guidewire and the centre of the origin of the lateral collateral ligament was the shortest at 130° knee flexion (8.0 ± 1.8 mm). The guidewires penetrated the origin of the lateral gastrocnemius tendon in 2 cases at 110° knee flexion and in 1 case each at 90° and 130° knee flexion.

CONCLUSIONS

When using the far anteromedial portal technique, more than 110° knee flexion is desirable to achieve ideal femoral tunnel length and avoid articular cartilage injury. In addition, the risk of damage to the origin of the lateral collateral ligament increases when the knee flexion angle increases to 130°. A knee flexion angle between 110° and 120° was recommended when using the far anteromedial portal technique.

Iliotibial band irritation caused by the EndoButton after anatomic double-bundle anterior cruciate ligament reconstruction: report of two cases

Two patients underwent arthroscopic anatomic double-bundle anterior cruciate ligament (ACL) reconstruction using the EndoButton for femoral fixation. The femoral tunnels were created by the inside-out technique through a far anteromedial portal. The patients postoperatively developed moderate lateral knee pain without instability. At the second-look arthroscopic evaluation, the two EndoButtons were removed. Both patients were completely asymptomatic several months after implant removal, implying that the EndoButtons caused the mechanical irritation in the iliotibial band. This is the first report describing removal of EndoButtons because of pain caused by friction with the iliotibial band. In anatomic ACL reconstruction, if the femoral tunnel exit is positioned near the lateral femoral epicondyle, care should be taken to prevent iliotibial band friction syndrome that could result because of the EndoButton.

Double-bundle ACL reconstruction: novice surgeons utilizing computer-assisted navigation versus experienced surgeons

PURPOSE

Anatomic double-bundle ACL reconstruction presents a unique technical challenge for surgeons, requiring precise placement of multiple tunnels in a relatively small area. As the necessity of anatomic reconstruction has been stressed throughout the literature, developing a method to consistently improve the accuracy and precision of tunnel placement is essential. We aimed to investigate whether computer-assisted navigation allows novice surgeons to place double-bundle ACL tunnels with a similar degree of accuracy to experienced surgeons operating without computer assistance.

METHODS

A novice surgeon group comprising three medical students performed double-bundle ACL reconstruction using passive computer-assisted navigation in 11 cadaver knees. Their individual results were compared to those of three experienced orthopaedic surgeons, each performing the identical procedure without the use of computer-assisted navigation in 9 cadaver knees.

RESULTS AND CONCLUSION

There were no significant differences in placement of either the AM or PL tunnels on the tibial plateau between the novice surgeons using computer-assisted navigation and the experienced surgeons. However, on the lateral femoral condyle, the novice surgeons placed the AM and PL tunnels significantly more anterior along Blumensaat's line, on average, compared to the experienced surgeons.

Accuracy and reliability of length measurements on three-dimensional computed tomography using open-source OsiriX software

There is a growing interest in three-dimensional computed tomography (3D-CT) as a research tool for the study of bone, joint anatomy, and kinematics. However, when CT data are processed and handled manually using image processing programs to yield 3D image and coordinate value, systematic and random errors should be validated. We evaluated the accuracy and reliability of length measurement on CT with OsiriX software. 3D-CT scans were made of 14 frozen pig knees with five transosseous holes in the metaphyseal portion of femur. The lengths between tunnel orifices were measured using Mitutoyo Digimatic digital calipers to establish the gold standard, and with the OsiriX program in 3D multi-planar reformatting mode for comparison. All measurements were recorded by a principal (replicate 1, trial 1) and a secondary observer (replicate 2, trial 1) and were repeated once by each observer (trial 2). The mean differences between OsiriX and real measurements were less than 0.1 mm in both replicates, and maximum differences were less than 0.3 mm. There were no significant differences between the replicates and real measurements (p=0.544 and 0.622 for replicates 1 and 2, respectively). The intraclass correlation coefficients (ICC) were very high between trials and between replicates (ICC=0.998 and 0.999, respectively). For kinematic analysis of the knees, length measurements on 3D-CT using OsiriX program can be used as alternatives to real measurements with less than 0.3-mm accuracy and very high reliability.

Comparison of femoral graft bending angle and tunnel length between transtibial technique and transportal technique in anterior cruciate ligament reconstruction

PURPOSE

To investigate which technique would reduce bending stress at the femoral tunnel aperture and make short tunnel length after ACL reconstruction by comparing the femoral graft bending angle and tunnel length between the single-bundle (SB) transtibial (TT) and double-bundle (DB) transportal (TP) technique using three-dimensional-computed tomography using OsiriX(®) imaging software.

METHODS

Forty-nine patients underwent an ACL reconstruction using a SB TT (Group I, 20 patients) and DB TP (Group II, 29 patients) technique. Femoral graft bending angle and femoral tunnel length were measured by CT image using OsiriX(®) imaging software. Groups I and II were compared, and statistical analysis was performed using SPSS software.

RESULTS

The mean anteromedial (AM) and posterolateral (PL) femoral graft bending angle of group II (111.5 ± 8.8° and 118.9 ± 9.8°, respectively) was significantly more acute than that of group I (125.3 ± 11.1°) (P < 0.001, P = 0.04). The mean femoral tunnel length of group I was significantly longer than that of group II (P = 0.001).

CONCLUSIONS

The femoral graft bending angle and the femoral tunnel length of the TP technique performed in the maximally flexed knee position was more acute and shorter than those of the TT technique after ACL reconstruction. This might increase the bending stress at the femoral tunnel aperture and shorter graft length in the tunnel after an ACL reconstruction using TP technique compared to the TT technique.

LEVEL OF EVIDENCE

III.

The accuracy of bone tunnel position using fluoroscopic-based navigation system in anterior cruciate ligament reconstruction

PURPOSE

The first purpose of this study was to examine whether fluoroscopic-based navigation system contributes to the accuracy and reproducibility of the bone tunnel placements in single-bundle anterior cruciate ligament (ACL) reconstruction. The second purpose was to investigate the application of the navigation system for double-bundle ACL reconstruction.

METHODS

A hospital-based case-control study was conducted, including a consecutive series of 55 patients. In 37 patients who received single-bundle ACL reconstruction, surgeries were performed with this system for 19 knees (group 1) and without this system for 18 knees (group 2). The positioning of the femoral and tibial tunnels was evaluated by plain sagittal radiographs. In 18 patients who received double-bundle ACL reconstruction using the navigation system (group 3), the bone tunnel positions were assessed by three-dimensional computed tomography (3D-CT). Clinical assessment of all patients was followed with the use of Lysholm Knees Score and IKDC.

RESULTS

Taking 0% as the anterior and 100% as the posterior extent, the femoral tunnels were 74.9 ± 3.0% in group 1 and 71.5 ± 5.8% in group 2 along Blumensaat's line, and the tibial tunnels were 42.3 ± 1.4% in group 1 and 42.5 ± 4.6% in group 2 along the tibia plateau. The bone tunnel positions in group 1 were located significantly closer to the position planned preoperatively and varied less in both femur and tibial side, compared with those without navigation (group 2). (Femur: P < 0.05, Tibia: P < 0.001) 3D-CT evaluation of double-bundle ACL reconstruction (group 3) also demonstrated that the bone tunnel positions of both anteromedial (AM) and posterolateral (PL) were placed as we expected.

CONCLUSION

The fluoroscopic-based navigation system contributed to the more reproducible placement of the bone tunnel during single-bundle ACL reconstruction compared with conventional technique. Additionally, this device was also useful for double-bundle ACL reconstruction.

LEVEL OF EVIDENCE

Case-control study, Therapeutic study, Level III.

A CT-based classification of prior ACL femoral tunnel location for planning revision ACL surgery

PURPOSE

The purposes of this study are to describe an ACL femoral tunnel classification system for use in planning revision ACL reconstruction based on 3-D computed tomography (CT) reconstructions and to evaluate its inter- and intra-rater reliability.

METHODS

A femoral tunnel classification system was developed based on the location of the femoral tunnel relative to the lateral intercondylar ridge. The femoral tunnel was classified as Type I if it was located entirely below and posterior to the ridge as viewed from distally, Type II if it was slightly malpositioned (either vertically, anteriorly, or both), and Type III if it was significantly malpositioned. To evaluate the reproducibility of the classification system, CT scans of 27 knees were obtained from patients scheduled for revision ACL reconstruction, and 3-D reconstructions were created. Four views of the 3-D reconstruction of each femur were then obtained, and inter- and intra-observer reliability was determined following classification of the tunnels by eight observers.

RESULTS

Twenty-five tunnels were classified as Type I (5 tunnels), Type II (9 tunnels), or type III (11 tunnels) by at least 5 of 8 observers, while insufficient agreement was noted to classify two tunnels. The interobserver reliability of tunnel classification as type I, II, or III yielded a κ coefficient of 0.57, while intra-observer reliability yielded a κ coefficient of 0.67. Subclassification of type II femoral tunnels into the subgroups anterior, vertical, and both was possible in four of the nine type II patients. The interobserver reliability of the complete classification system yielded a κ coefficient of 0.50, while the intra-observer reliability yielded a κ coefficient of 0.54.

CONCLUSION

Classification of the location of ACL femoral tunnels utilizing 3-D reconstructions of CT data yields moderate to substantial inter- and intra-observer reliability.

LEVEL OF EVIDENCE

Diagnostic Level III.

Three-dimensional fluoroscopic navigation guidance for femoral tunnel creation in revision anterior cruciate ligament reconstruction

Revision anterior cruciate ligament (ACL) reconstruction is accompanied by several technical challenges that must be addressed, such as a primary malpositioned bone tunnel, pre-existing hardware, or bone defects due to tunnel expansion. We describe a surgical technique used to create an anatomic femoral socket using a 3-dimensional (3D) fluoroscopy-based navigation system in technically demanding revision cases. After a reference frame is rigidly attached to the femur, an intraoperative image of the distal femur is obtained, which is transferred to a navigation system and reconstructed into a 3D image. A navigation computer helps the surgeon to visualize the whole image of the lateral wall of the femoral notch, even if the natural morphology of the intercondylar notch has been destroyed by the primary procedure. In addition, the surgeon can also confirm the position of the previous bone tunnel aperture, the previous exit of the femoral tunnel, and the presence of any pre-existing hardware on the navigation monitor. When a new femoral guidewire for the revision procedure is placed, the virtual femoral tunnel is overlaid on the reconstructed 3D image in real time. At our institution, 12 patients underwent 1-stage revision ACL procedures with the assistance of this computer navigation system, and the grafts were securely fixed in anatomically created tunnels in all cases. This technology can assist surgeons in creating anatomic femoral tunnels in technically challenging revision ACL reconstructions.

Clinical results of technique for double bundle anterior cruciate ligament reconstruction using hybrid femoral fixation and Retroscrew

Background

Anatomic anterior cruciate ligament (ACL) reconstruction has been presented as a means to more accurately restore the native anatomy of this ligament. This article describes a new method that uses a double bundle to perform ACL reconstruction and to evaluate the clinical outcome.

Methods

Grafts are tibialis anterior tendon allograft for anteromedial bundle (AMB) and hamstring tendon autograft without detachment of the tibial insertion for posterolateral bundle (PLB). This technique creates 2 tunnels in both the femur and tibia. Femoral fixation was done by hybrid fixation using Endobutton and Rigidfix for AMB and by biointerference screw for PLB. Tibial fixations are done by Retroscrew for AMB and by native insertion of hamstring tendon for PLB. Both bundles are independently and differently tensioned. We performed ACL reconstruction in 63 patients using our new technique. Among them, 47 participated in this study. The patients were followed up with clinical examination, Lysholm scales and International Knee Documentation Committee (IKDC) scoring system and radiological examination with a minimum 12 month follow-up duration.

Results

Significant improvement was seen on Lachman test and pivot-shift test between preoperative and last follow-up. Only one of participants had flexion contracture about 5 degrees at last follow-up. In anterior drawer test by KT-1000, authors found improvement from average 8.3 mm (range, 4 to 18 mm) preoperatively to average 1.4 mm (range, 0 to 6 mm) at last follow-up. Average Lysholm score of all patients was 72.7 ± 8.8 (range, 54 to 79) preoperatively and significant improvement was seen, score was 92.2 ± 5.3 (range, 74 to 97; p < 0.05) at last follow-up. Also IKDC score was normal in 35 cases, near normal in 11 cases, abnormal in 1 case at last follow-up.

Conclusions

Our new double bundle ACL reconstruction technique used hybrid fixation and Retroscrew had favorable outcomes.