Evaluation of the bone bridge between the bone tunnels after anatomic double-bundle anterior cruciate ligament reconstruction: a multidetector computed tomography study

Less tunnel enlargement in triple-bundle versus double-bundle anterior cruciate ligament reconstruction: A randomized clinical trial

BACKGROUND

No study thus far has compared tunnel enlargement between double-bundle and triple-bundle anterior cruciate ligament reconstruction. We compared tibial tunnel enlargement and rate of tibial tunnel coalition between these two reconstructions, hypothesizing that tibial tunnel enlargement in triple-bundle reconstruction is less than that in double-bundle reconstruction, and that the tunnel coalition rate is equal between the two procedures.

METHODS

This prospective randomized clinical trial included 25 patients who underwent computed tomography 2 weeks and 1 year postoperatively. Eleven patients underwent double-bundle anterior cruciate ligament reconstruction and 14 underwent triple-bundle anterior cruciate ligament reconstruction. Tunnel positions and tunnel coalition at the tibial tunnel aperture were assessed using three-dimensional computed tomography. Tunnel enlargement rate was calculated by measuring the sagittal and axial widths of the tibial bone tunnel 10 mm from the tibial tunnel aperture. These parameters were then compared between the groups.

RESULTS

The changes in tunnel positions and tunnel coalitions between groups were not significantly different. On both sagittal and axial views, the tunnel enlargement rates of the medial and lateral sections of the anteromedial bundle in the triple-bundle group were significantly smaller than those in the double-bundle group (sagittal view, p = 0.02 and < 0.01, respectively; axial view, p = 0.02 and ≤ 0.05, respectively). The groups did not differ significantly in terms of posterolateral tunnel enlargement.

CONCLUSION

Tunnel widening in the medial and lateral sections of the anteromedial bundle-associated tibial tunnel in triple-bundle anterior cruciate ligament reconstruction was smaller than that of double-bundle reconstruction. The tunnel coalition rates between the two reconstructions were not significantly different.

Three-dimensional-printed patient-specific instrumentation is an accurate tool to reproduce femoral bone tunnels in multiple-ligament knee injuries

PURPOSE

Multiple-ligament knee reconstruction techniques often involve the creation of several bone tunnels for various reconstruction grafts. A critical step in this procedure is to avoid short tunnels or convergences among them. Currently, no specific template guide to reproduce these angulations has been reported in the literature, and the success of the technique still depends on the experience of the surgeon. The aim of this study is to analyze the accuracy and reliability of 3D-printed patient-specific instrumentation (PSI) for lateral and medial anatomical knee reconstructions.

METHODS

Ten cadaveric knees were scanned by computed tomography (CT). Using specific computer software, anatomical femoral attachments were identified: (1) on the lateral side the lateral collateral ligament (LCL) and the popliteal tendon (PT) and (2) on the medial side the medial collateral ligament (MCL) and the posterior oblique ligament (POL). Four bone tunnels were planned for each knee, and PSI with different directions were designed as templates to reproduce the planned tunnels during surgery. Twenty 3D-printed PSI were used: ten were tailored to the medial side for reconstructing MCL and POL tunnels, and the other ten were tailored to the lateral side for reconstructing LCL and PT tunnels. Postoperative CT scans were made for each cadaveric knee. The accuracy of the use of 3D-printed PSI was assessed by superimposing post-operative CT images onto pre-operative images and analyzing the deviation of tunnels performed based on the planning, specifically the entry point and the angular deviations.

RESULTS

The median entry point deviations for the tunnels were as follows: LCL tunnel, 1.88 mm (interquartile range (IQR) 2.2 mm); PT tunnel, 2.93 mm (IQR 1.17 mm); MCL tunnel, 1.93 mm (IQR 4.26 mm); and POL tunnel, 2.16 mm (IQR 2.39). The median angular deviations for the tunnels were as follows: LCL tunnel, 2.42° (IQR 6.49°); PT tunnel, 4.15° (IQR 6.68); MCL tunnel, 4.50° (IQR 6.34°); and POL tunnel, 4.69° (IQR 3.1°). No statistically significant differences were found in either the entry point or the angular deviation among the different bone tunnels.

CONCLUSION

The use of 3D-printed PSI for lateral and medial anatomical knee reconstructions provides accurate and reproducible results and may be a promising tool for use in clinical practice.

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.

Anatomic double-bundle anterior cruciate ligament reconstruction could not achieve sufficient control of pivot-shift when accompanying tibial tunnel coalition

PURPOSE

To evaluate the effect of tibial tunnel coalition on knee rotatory laxity and clinical outcomes after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction.

METHODS

Forty-one patients who underwent anatomic DB ACL reconstruction were included prospectively. Three-dimensional computed tomography of the knee joint was obtained at approximately 1 year postoperatively to determine if tunnel coalition occurred. After excluding seven cases of femoral tunnel coalition, two groups were established based on the existence of a tibial tunnel coalition. The pivot-shift test was quantitatively evaluated on the basis of tibial acceleration preoperatively and at 1 year postoperatively. Two subjective scores, the International Knee Documentation Committee (IKDC) subjective and Lysholm scores, were also collected. The pivot-shift measurement and subjective scores were compared between the ACL-reconstructed knees with and without tibial tunnel coalition. The independent t test, Pearson's chi-square test, and Student t tests were used in data analysis.

RESULTS

Twenty-one knees had tibial tunnel coalition (group C), whereas 13 knees did not have tunnel coalition(group N). Pivot-shift was significantly diminished postoperatively in both groups on the basis of the clinical examination and quantitative evaluations (p < 0.05). However, there was a small but significant difference in tibial acceleration demonstrating larger pivot-shift in group C (1.0 ± 0.6 m/s²) than in group N (0.5 ± 0.3 m/s², p < 0.05). No significant difference was observed in the IKDC subjective and Lysholm scores (both n.s.).

CONCLUSION

When the tibial tunnel coalition occurs after DB ACL reconstruction, knee rotatory laxity may not be restored in ACL-reconstructed knees, as expected in those without tunnel coalition. It is recommended that two tibial tunnels should be created separately when performing DB-ACL reconstruction to achieve better control of rotatory knee laxity.

LEVEL OF EVIDENCE

III.

ANATOMICAL STUDY OF THE POSTEROLATERAL LIGAMENT COMPLEX OF THE KNEE: LCL AND POPLITEUS TENDON

Objective:

To analyse the distances between the femoral insertions of the popliteus tendon (PT) and the lateral collateral ligament (LCL) through dissections of cadaveric specimens in a mixed population.

Methods:

Fresh cadavers were dissected, and the anthropometric data of all specimens were recorded. The distances from the origin of the PT to the LCL in the femoral region and the diameter of each structure were measured using a digital calliper.

Results:

In total, 11 unpaired knees were dissected, eight men and three women, with an average age of 71.5 ± 15.2 years, weight of 57.2 ± 15.6 kg, and a mean height of 170.5 ± 8.2 cm. The distance from the center of the femoral footprint of the LCL to the PT was 10.0 ± 2.4 mm. The distances between the edges closest to each other and those more distant from each other were 3.1 ± 1.1 mm and 16.3 ± 2.4 mm, respectively.

Conclusion:

The distance between the midpoints of the PT and the LCL in our mixed population is smaller than the distances often reported in the literature. PLC reconstruction with separate tunnels for the LCL and PT may not be technically possible for individuals of any population.Level of Evidence III, Diagnostic studies.

Comparison of Tunnel Enlargement and Clinical Outcome Between Bioabsorbable Interference Screws and Cortical Button-Post Fixation in Arthroscopic Double-Bundle Anterior Cruciate Ligament Reconstruction: A Prospective, Randomized Study With a Minimum Follow-Up of 2 Years

PURPOSE

To investigate the tunnel enlargement rate and clinical function by comparing double-bundle anterior cruciate ligament reconstruction (ACLR) using different fixation devices.

METHODS

Patients receiving primary arthroscopic double-bundle ACLR were screened and divided into 2 groups on the basis of the method of graft fixation: bioabsorbable interference screw (BS) group and cortical button (CB) group. Bone tunnel size was assessed digitally using magnetic resonance imaging, which was performed a minimum of 2 years postoperatively. Clinical evaluations were performed using the Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee score, and KT-1000 arthrometer 2 years postoperatively.

RESULTS

Sixty patients receiving primary arthroscopic double-bundle ACLR were included. Overall, the BS group showed greater tunnel enlargement than the CB group, as well as a significantly increased rate of tunnel communication (P = .029). The average anteromedial tunnel enlargement rates for the BS and CB groups were 50% and 28%, respectively. The enlargement rate of the posterolateral (PL) femoral tunnel was similar in both groups. In the PL tibial tunnel, the CB group showed a significant increase in enlargement compared with the BS group (64% vs 45%, P = .0001). Both groups showed functional improvement in the Knee Injury and Osteoarthritis Outcome Score and International Knee Documentation Committee score. No significant difference in postoperative functional outcomes was found between the 2 groups.

CONCLUSIONS

The BS group showed significantly greater tunnel enlargement in anteromedial tunnels and an increased tunnel communication rate compared with the CB group. On the other hand, the CB group showed greater tunnel enlargement in tibial PL tunnels. Tunnel communication was observed mostly on the tibial side in the BS patients. Equivalent clinical function outcomes were noted at 2 years after surgery in both groups of patients.

LEVEL OF EVIDENCE

Level II, randomized controlled clinical trial.

Comparison of three approaches for femoral tunnel during double-bundle anterior cruciate ligament reconstruction: A case controlled study

BACKGROUND

It is still controversial whether which femoral tunnel creation technique is best during anterior cruciate ligament reconstruction (ACLR). We aimed to clarify the features of three different techniques based on the femoral tunnel position created with the same tunnel-creating concept and the measurement data.

METHODS

The femoral tunnel of double-bundle (DB) ACLR was created using the behind-remnant approach in a remnant preserved manner following the policy of our institute. The trans-tibial approach (TT) was applied for all primary ACL injured cases until December 2012. The trans-portal approach (TP) was applied from January to September 2013, and the outside-in approach (OI) was indicated from October 2013 to March 2014. We compared the femoral tunnel aperture positions with the postoperative three-dimensional computed tomography (3D-CT). Additionally, the femoral tunnel length and the septum distance of each anteromedial (AM) and posterolateral (PL) tunnel were analyzed.

RESULTS

The AM tunnel aperture position of TT was significantly higher and shallower than that of TP in knee flexion position. The femoral tunnel length of TP was significantly shorter than that of TT and OI. The septum between each tunnel of OI trended wider than that of TT and TP.

CONCLUSIONS

The AM tunnel aperture position of TT runs the risk of a high and shallow position. TP runs the risk of insufficiently short tunnel length. It is important to apply each method flexibly to each case because no single best approach was found.

Effects of Remnant Tissue Preservation on Tunnel Enlargement After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Using the Hamstring Tendon

Background

The effects of remnant tissue preservation on tunnel enlargement after anatomic double-bundle anterior cruciate ligament (ACL) reconstruction have not yet been established.

Hypothesis

The preservation of ACL remnant tissue may significantly reduce the degree and incidence of tunnel enlargement after anatomic double-bundle ACL reconstruction, while the remnant-preserving procedure may not significantly increase the incidence of tunnel coalition after surgery.

Study Design

Cohort study; Level of evidence, 2.

Methods

A total of 79 patients underwent anatomic double-bundle ACL reconstruction. Based on the Crain classification of ACL remnant tissue, 40 patients underwent the remnant-preserving procedure (group P), and the remaining 39 patients underwent the remnant-resecting procedure (group R). There were no differences between the 2 groups concerning all background factors, including preoperative knee instability and intraoperative tunnel positions. All patients were examined using computed tomography and a standard physical examination at 2 weeks and 1 year after surgery.

Results

During surgery, the femoral and tibial anteromedial (AM) tunnel sizes in both groups averaged 6.6 and 6.5 mm, respectively. The femoral and tibial posterolateral (PL) tunnel sizes in both groups averaged 6 and 6 mm, respectively. There were no differences in the intraoperative tunnel positions and tunnel sizes between groups. Concerning the femoral AM tunnel, the degree of tunnel enlargement in the oblique coronal and oblique axial views in group P was significantly less than that in group R (P = .0068 and .0323, respectively). Regarding the femoral AM tunnel cross-sectional area, the degree and incidence of tunnel enlargement in group P were significantly less than those in group R (P = .0086 and .0278, respectively). There were no significant differences in tunnel coalition between groups. In each group, there were no significant relationships between tunnel enlargement and each clinical outcome.

Conclusion

Remnant preservation in anatomic double-bundle ACL reconstruction reduced enlargement of the femoral AM tunnel and did not increase the incidence of tunnel coalition. This is one of the advantages of remnant-preserving ACL reconstruction.

Influence of knee flexion angle and transverse drill angle on creation of femoral tunnels in double-bundle anterior cruciate ligament reconstruction using the transportal technique: Three-dimensional computed tomography simulation analysis

BACKGROUND

The purpose of this study was to find appropriate flexion angle and transverse drill angle for optimal femoral tunnels of anteromedial (AM) bundle and posterolateral (PL) bundle in double-bundle ACL reconstruction using transportal technique.

METHODS

Thirty three-dimensional knee models were reconstructed. Knee flexion angles were altered from 100° to 130° at intervals of 10°. Maximum transverse drill angle (MTA), MTA minus 10° and 20° were set up. Twelve different tunnels were determined by four flexion angles and three transverse drill angles for each bundle. Tunnel length, wall breakage, inter-tunnel communication and graft-bending angle were assessed.

RESULTS

Mean tunnel length of AM bundle was >30mm at 120° and 130° of flexion in all transverse drill angles. Mean tunnel length of PL bundle was >30mm during every condition. There were ≥1 cases of wall breakage except at 120° and 130° of flexion with MTA for AM bundle. There was no case of wall breakage for PL bundle. Considering inter-tunnel gap of >2mm without communication and obtuse graft-bending angle, 120° of flexion and MTA could be recommended as optimal condition for femoral tunnels of AM and PL bundles.

CONCLUSION

Flexion angle and transverse drill angle had combined effect on femoral tunnel in double-bundle ACL reconstruction using transportal technique. Achieving flexion angle of 120° and transverse drill angle close to the medial femoral condyle could be recommended as optimal condition for femoral tunnels of AM and PL bundles to avoid insufficient tunnel length, wall breakage, inter-tunnel communication and acute graft-bending angle.

Opportunistic Use of CT Imaging for Osteoporosis Screening and Bone Density Assessment: A Qualitative Systematic Review

BACKGROUND

The purpose of this study was to determine the clinical opportunities for the use of computed tomography (CT) imaging for inferring bone quality and to critically analyze the correlation between dual x-ray absorptiometry (DXA) and diagnostic CT as reported in the literature.

METHODS

A systematic review of the MEDLINE database was performed in February 2016 using the PubMed interface. The inclusion criteria were English language, studies performed using living human subjects, studies pertaining to orthopaedics, use of conventional diagnostic CT scans, studies that measured cancellous bone, and studies that reported Hounsfield unit (HU) measurements directly rather than a computed bone mineral density.

RESULTS

Thirty-seven studies that reported on a total of 9,109 patients were included. Of these, 10 studies correlated HU measurements of trabecular bone with DXA-based bone assessment. Reported correlation coefficients ranged between 0.399 and 0.891, and 5 of the studies reported appropriate threshold HU levels for diagnosing osteoporosis or osteopenia.

CONCLUSIONS

Direct HU measurement from diagnostic CT scans has the potential to be used opportunistically for osteoporosis screening, but in its current state it is not ready for clinical implementation. There is a lack of exchangeability among different machines that limits its broad applicability. Future research efforts should focus on identifying thresholds at specific anatomic regions in high-risk patients in order to have the greatest impact on patients. However, using diagnostic CT to infer region-specific osteoporosis could be extraordinarily valuable to orthopaedic surgeons and primary care physicians, and merits further research.

Femoral and Tibial Tunnel Diameter and Bioabsorbable Screw Findings After Double-Bundle ACL Reconstruction in 5-Year Clinical and MRI Follow-up

Background:

Tunnel enlargement is frequently seen in short-term follow-up after anterior cruciate ligament reconstruction (ACLR). According to new evidence, tunnel enlargement may be followed by tunnel narrowing, but the long-term evolution of the tunnels is currently unknown.

Hypothesis/Purpose:

The hypothesis was that tunnel enlargement is followed by tunnel narrowing caused by ossification as seen in follow-up using magnetic resonance imaging (MRI). The purpose of this study was to evaluate the ossification pattern of the tunnels, the communication of the 2 femoral and 2 tibial tunnels, and screw absorption findings in MRI.

Study Design:

Case series; Level of evidence, 4.

Methods:

Thirty-one patients underwent anatomic double-bundle ACLR with hamstring grafts and bioabsorbable interference screw fixation and were followed with MRI and clinical evaluation at 2 and 5 years postoperatively.

Results:

The mean tunnel enlargement at 2 years was 58% and reduced to 46% at 5 years. Tunnel ossification resulted in evenly narrowed tunnels in 44%, in conical tunnels in 48%, and fully ossified tunnels in 8%. Tunnel communication increased from 13% to 23% in the femur and from 19% to 23% in the tibia between 2 and 5 years and was not associated with knee laxity. At 5 years, 54% of the screws were not visible, with 35% of the screws replaced by a cyst and 19% fully ossified. Tunnel cysts were not associated with worse patient-reported outcomes or knee laxity. Patients with a tibial anteromedial tunnel cyst had higher Lysholm scores than patients without a cyst (93 and 84, P = .03).

Conclusion:

Tunnel enlargement was followed by tunnel narrowing in 5-year follow-up after double-bundle ACLR. Tunnel communication and tunnel cysts were frequent MRI findings and not associated with adverse clinical evaluation results.

Tunnel widening in single- versus double-bundle anterior cruciate ligament reconstructed knees

PURPOSE

The consequence of tunnel widening after ACL reconstructions is foremost of importance in case of revision surgery. Tunnel expansion leads to bone loss close to the joint, and additional surgery with bone grafting prior to revision surgery might be necessary. The purpose of the study was to measure widening of the tunnels in single-bundle (SB) and double-bundle (DB) ACL reconstructed knees during the first year after surgery, detected by a novel, semi-automated 3D CT imaging modality. Our hypothesis was that there would be a difference between the initial tunnel size and the size measured one year post-operatively due to the tunnel widening process. Further, the purpose was to evaluate whether there were any differences in the amount of tunnel widening between the two surgical techniques.

METHODS

Twenty patients who underwent DB ACL reconstruction, and 22 patients who underwent SB ACL reconstruction, performed a CT scan of the bony tunnels, during their first days after surgery and one year post-operatively. The CT scans were transformed into 3D CT reconstructions, and the tunnels were measured with the "best-fit cylinder" method, measurements at the level of tunnel aperture and 10.0 mm from the joint line.

RESULTS

All tunnels in the DB and SB ACL reconstructed knees exhibited widening during the first year after the operation (p < 0.001). The SB femoral tunnels showed more widening compared to the DB femoral AM tunnels (1.4 ± 0.9 vs. 0.5 ± 0.6 mm) (p < 0.001), and the SB tibial tunnels widened more compared to the DB tibial PL tunnels (1.0 ± 1.0 vs. 0.5 ± 0.6) (p < 0.043).

CONCLUSION

All tunnels widened during the first year after the ACL reconstruction with a larger amount of widening in the SB tunnels compared to the DB femoral AM tunnels and the DB tibial PL tunnels. This is the first study to detect tunnel widening in DB reconstructed knees through a semi-automated 3D CT imaging modality.

LEVEL OF EVIDENCE

Prospective cohort study, Level III.

Graft quality and clinical outcomes of intraoperative bone tunnel communication in anatomic double-bundle anterior cruciate ligament reconstruction

Background/objective

In anatomic double-bundle anterior cruciate ligament reconstruction, it is crucial to create two separate bone tunnels within the footprints of the anterior cruciate ligament at the femur and tibia. This can occasionally be difficult to accomplish and the adverse effects of bone tunnel communication are unclear. The purpose of this study was to examine the effects of intraoperative bone tunnel communication on graft quality and clinical outcome.

Methods

Fifty-two patients (52 knees) who underwent anatomic double-bundle anterior cruciate ligament reconstruction with hamstring tendons were included. The mean age of the patients was 30.7 years. Clinical assessments were performed 1 year after surgery. Bone tunnel communication was evaluated using computed tomography 10 days after surgery. Graft quality was evaluated using magnetic resonance imaging 6 months after surgery and the signal/noise quotient was calculated using the region of interest technique.

Results

Bone tunnel communication was observed in the femur of one knee (1.9%) and the tibias of 10 knees (30.8%). The knees with tibial bone communication were classified into Group C (N = 16), and the knees without tibial bone tunnel communication were classified into Group N (N = 36). No significant differences were observed between Groups C and N in terms of clinical outcome. The signal/noise quotient of the distal portion of the posterolateral graft in Group C was significantly higher than that of Group N.

Conclusion

Bone tunnel communication in anatomic double-bundle anterior cruciate ligament reconstruction did not affect clinical outcome, but it did affect posterolateral graft quality.

Level of evidence

Level 4, case series, therapeutic studies.

Tunnel communication and increased graft signal intensity on magnetic resonance imaging of double-bundle anterior cruciate ligament reconstruction

PURPOSE

This study aimed to evaluate the association between magnetic resonance imaging (MRI) findings of tunnel communication and increased graft signal intensity (SI) and clinical evaluation of knee stability and outcome after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction.

METHODS

Fifty-nine patients were evaluated with 1.5 T MRI and with clinical evaluation 2 years after DB ACL reconstruction. The MRI finding of tunnel communication was defined as the absence of a bony bridge between the anteromedial (AM) and posterolateral (PL) tunnels. The SI of the intra-articular portion of both grafts was analyzed on proton-density (PD)-weighted and T2-weighted images and graded on a scale, with I being a normal SI similar to that of the posterior cruciate ligament, II being > 50% of the graft having a normal SI, and III being < 50% of the graft having a normal SI. The clinical evaluation of knee stability and function included KT-1,000 arthrometric side-to-side difference, pivot shift test, and International Knee Documentation Committee (IKDC) and Lysholm knee evaluation scores. The association between the MRI findings and the clinical findings was calculated using the Fisher exact test and the 2-tailed t test.

RESULTS

Tunnel communication was seen in the femur in 10% of patients and in the tibia in 27% of patients. Increased graft SI was seen in 15% of the AM grafts and 59% of the PL grafts. No statistically significant association (P < .05) between the MRI findings of tunnel communication or increased graft SI and knee laxity was found.

CONCLUSIONS

The MRI findings of tunnel communication or increased graft SI were not associated with knee laxity 2 years after DB ACL reconstruction. Tibial tunnel communication was associated with increased range of movement with flexion, and increased AM graft SI was associated with reduced range of flexion in the knee.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

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.

Correlation between femoral guidewire position and tunnel communication in double bundle anterior cruciate ligament reconstruction

PURPOSE

The object of this study was to determine the shortest possible distances of antero-medial (AM) and postero-lateral (PL) guide wire tunnel positions required to prevent femoral bone tunnel communication in double-bundle anterior cruciate ligament (ACL) reconstruction using human cadaver knees.

MATERIALS AND METHODS

The centers of femoral AM and PL bundles of 16 cadaveric knees were drilled with guide wires and the distances of guide wires, were measured upon entrance into the bone. Femoral tunnel drilling was performed using transportal technique. The diameters of AM and PL graft were 8 mm and 6 mm, respectively. CT scans were taken on each knee, and 3-dimensional models were constructed to identify the femoral tunnel position and to create AM and PL tunnel virtual cylinders. Thickness of the bone bridge between the two tunnels was measured.

RESULTS

In four out of six specimens, in which the guide wires were placed at less than or equal to 9 mm, communication was noted. In specimens with guide wires placed at distances greater than or equal to 10 mm, communication was not noted. The two groups showed a statistically significant difference (p=0.008). In cases where the distance between the AM and PL femoral tunnel guide wires was 12 mm, the bone bridge thickness was greater than 2 mm along the tunnel.

CONCLUSION

The technique for double bundle-anterior cruciate ligament (DB-ACL) reconstruction that we show here can avoid bone tunnel communication when AM and PL femoral guide wires are placed at least 10 mm apart, and 12 mm should be kept to preserve 2 mm bone bridge thickness.

Comparison of femoral tunnel widening between outside-in and trans-tibial double-bundle ACL reconstruction

PURPOSE

The objectives of this study were to compare (1) the degree of widening by comparing the diameter at the most widened area and the site of widening by measuring the distance from the tunnel entrance to the most widened area in two femoral tunnels (anteromedial and posterolateral), and (2) the morphologic change at the tunnel entrance between outside-in and trans-tibial double-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

A retrospective study that included 17 trans-tibial and 19 outside-in double-bundle ACL reconstructed patients was conducted for evaluation of serial computed tomography (CT) scan (immediate post-operation and post-operative 1 year). Digital image communication in medicine (DICOM) data was extracted from the PiViewSTAR and imported into OsiriX, which was installed on a Macbook Pro laptop computer. Diameter of the most widened area and distance from the entrance to this point were measured from each of two perpendicular (sagittal and coronal) planes that were accurately realigned parallel to the tunnel direction. Change in the morphology of the tunnel entrance between immediate post-operation and 1-year post-operation was evaluated.

RESULTS

Widening was observed in both planes of both tunnels in the two techniques. However, no statistical significances in the diameter of most widened area and distance from the tunnel entrance to the most widened point were observed between the both techniques (n.s.). Distances from the centre point to each four sections showed an increase in all four sections of all both tunnels in both techniques. However, no statistical significance was observed between the two techniques (n.s.).

CONCLUSION

Widening was observed in all tunnels using both techniques and degrees, and sites of the widening did not differ between groups. Morphologic change at the tunnel entrance was not limited to the specific direction and occurred in all directions without significant difference between groups.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

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.

MRI evaluation of the four tunnels of double-bundle ACL reconstruction

BACKGROUND

The double-bundle (DB) reconstruction of the anterior cruciate ligament (ACL) has gained popularity in recent years. The positioning of anteromedial (AM) and posterolateral (PL) tunnels is aimed at the anatomic femoral and tibial attachments of AM and PL bundles of the native ACL.

PURPOSE

To use magnetic resonance imaging (MRI) to evaluate the tunnel locations and tunnel findings in DB ACL reconstruction.

MATERIAL AND METHODS

Sixty-six patients with DB ACL reconstruction were evaluated with 1.5-T MRI 2 years postoperatively. Two musculoskeletal radiologists separately measured the locations and the diameters of the tunnels. Inter-observer agreements were estimated according to the method of Bland and Altman.

RESULTS

In the femur, the mean AM tunnel location was 32% from the proximal condylar surface and 18% from the notch roof. The mean PL tunnel location was 42% and 43%, respectively. In the tibia, the mean AM tunnel location was 54% of the lateral-to-medial tibial width and 42% of the anterior-to-posterior tibial depth. The mean PL tunnel location was 54% and 56%, respectively. The mean tunnel enlargement was 3.8 mm (56%). Tunnel communication was seen in seven patients (11%) in the femur and in 19 patients (29%) in the tibia. Greater femoral AM tunnel distance from the proximal condylar surface was associated with more tunnel enlargement, and more posterior tibial PL tunnel location was associated with less tunnel enlargement.

CONCLUSION

The tunnel locations of DB ACL reconstruction can be evaluated with MRI. Tunnel location was associated with tunnel enlargement that in turn was associated with tunnel communication.

Change of the tunnel configuration in the non-anatomic trans-tibial double bundle ACL reconstruction

BACKGROUND

The objectives of this study were to evaluate tunnel widening and morphologic change at the tunnel aperture.

METHODS

A prospective study that included 17 trans-tibial double bundle anterior cruciate ligament (ACL) patients was conducted for the evaluation of serial computed tomography (CT) scan. The OsiriX was used for remodeling of CT images with a tunnel direction. Tunnel widening and change of the aperture morphology were assessed.

RESULTS

With regard to the comparison of tunnel widening of the anteromedial (AM) tunnel, the entrance (p=0.01) and mid (p=0.02) of the coronal image, and the entrance (p < 0.01) and mid (p < 0.01) of the sagittal image showed statistically significant differences. The entrance (p=0.01) of the sagittal image only showed statistical significance in the posterolateral (PL) tunnel. With regard to the comparison between the AM and PL tunnels, the mid-portion (p = 0.04) of the sagittal image showed statistical differences, and the AM tunnel showed larger widening than the PL tunnel. Change of tunnel aperture was observed in the posterior, medial, and lateral portions of the AM tunnel and the anterior, posterior, and lateral portions of the PL tunnel.

CONCLUSIONS

In some aspects, occurrence of tunnel widening was observed in most sites. Widening occurred mainly at the entrance and mid-portions of the AM tunnel and the entrance of the PL tunnel. Change of tunnel aperture was observed at most directions in both tunnels. This is a non-anatomic ACL reconstruction and similar study with anatomic ACL reconstruction would be required in the future.

TriLink: Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction

Cadaveric and clinical biomechanical studies show improved kinematic restoration using double-bundle anterior cruciate ligament (ACL) reconstruction techniques. These have been criticized in the past for being technically challenging. We present a novel 3-socket approach for anatomic "all-inside" double-bundle reconstruction using a single hamstring tendon fashioned to create a trifurcate graft: the TriLink technique. The semitendinosus alone is harvested, quadrupled, and attached to 3 suspensory fixation devices in a Y-shaped configuration, creating a 4-stranded tibial limb and 2 double-stranded femoral limbs. A medial viewing/lateral working arthroscopic approach is adopted using specifically designed instrumentation. Anatomic placement of the 2 femoral tunnels is performed by a validated direct measurement technique. A single mid-bundle position is used on the tibia. Both femoral and tibial sockets are created in a retrograde manner using outside-to-in drilling. This is a simplified operative technique for anatomic double-bundle ACL reconstruction that maximizes bone preservation. The TriLink construct replicates the 2 bundles of the ACL, conferring native functional anisometry and improving femoral footprint coverage while avoiding the complexities and pitfalls of double-tibial tunnel techniques. Preservation of the gracilis reduces the morbidity of hamstring harvest and allows greater flexibility in graft choice in cases requiring multiligament reconstruction.

Comparison of tunnel locations of double bundle ACL reconstruction using the conventional transtibial technique with anatomic tunnel locations using a 3D CT model

INTRODUCTION

The purposes of this study were: (1) to compare tunnel locations using the conventional transtibial technique with reference data, and (2) to identify factors that make it difficult to position the femoral tunnel correctly or contribute to breakage of the bone bridge between the two tibial tunnels.

MATERIALS AND METHODS

A prospective study was performed on 28 patients who underwent double bundle ACL reconstruction. Locations of each tunnel were determined using an anatomic coordinate axes method (ACAM). Measurements included: thickness of the bone bridge between tibial two tunnels (BB), height from the union (HU) point to expected joint surface, the ratio between the length of Blumensaat's line and the anterior-posterior length of the lateral femoral condyle (RBL), and the ratio between anterior-posterior and proximal-distal lengths of the medial wall of the lateral femoral condyle (RAPPD).

RESULTS

The posterior-anterior direction of femoral AM tunnel, the proximal-distal direction of femoral PL tunnel, and the posterior-anterior direction of femoral PL tunnel were statistically significantly different from the reference data. In correlation analyses between BB or HU and other variables, the AM tibial tunnel and RBL showed a moderate negative correlation. The cutoff point for tunnel breakage was an RLB of 1.14, meaning that the possibility of bone bridge breakage would increases for RBL values of >1.14.

CONCLUSIONS

It seems that conventional transtibial drilling technique used during double bundle ACL reconstruction does not reproduce correct tunnel locations compared with reference data. This problem was found to be related to the bony geometry of the medial wall of the lateral femoral condyle or the bone bridge between the two tibial tunnels. Our results indicate that RBL should be determined by pre-operative CT or plain lateral radiography, and that transtibial single bundle reconstruction or double bundle reconstruction using other methods should be attempted when the RBL exceeds 1.14.

Tunnel Enlargement and Coalition After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction With Hamstring Tendon Autografts: A Computed Tomography Study

Background:

Tunnel enlargement and coalition following double-bundle anterior cruciate ligament (ACL) reconstruction with hamstring tendon autografts has not yet been sufficiently studied.

Hypothesis:

The incidence and the degree of femoral tunnel enlargement will be significantly greater than those for tibial tunnel enlargement after anatomic double-bundle ACL reconstruction using hamstring tendon autografts. There will be no significant correlation between tunnel enlargement and coalition and the postoperative knee laxity.

Study Design:

Case series; Level of evidence, 4.

Methods:

Thirty-nine patients who underwent anatomic double-bundle ACL reconstruction using semitendinosus and gracilis tendon autografts were followed up for 1 year after surgery. The grafts were simultaneously fixed at 10° of knee flexion with EndoButtons and spiked staples. All patients were examined with computed tomography and the standard clinical evaluation methods at 2 weeks and 1 year after surgery.

Results:

The degree of tunnel enlargement of the femoral anteromedial and posterolateral tunnels averaged 10% to 11% and 7% to 9%, respectively, while that of the tibial anteromedial and posterolateral tunnels averaged 3% to 7% and 1% to 6%. The degree and incidence of the anteromedial and posterolateral tunnel enlargement were significantly greater in the femur than in the tibia (P < .0335 and P < .0405, respectively). On the femoral and tibial intra-articular surface, tunnel outlet coalition was found in 5% and 77% of the knees, respectively, at 1 year after surgery. There was no significant correlation between tunnel enlargement and coalition and the clinical outcome.

Conclusion:

The incidence and the degree of each tunnel enlargement in the femur were significantly greater than that in the tibia. However, the incidence of tunnel coalition in the femur was significantly less than that in the tibia after double-bundle ACL reconstruction with a transtibial technique. There was no significant correlation between tunnel enlargement and coalition and the clinical outcome.

Clinical Relevance:

The present study provides orthopaedic surgeons with important information on double-bundle ACL reconstruction with hamstring tendons.

Specific compartmental analysis of cartilage status in double-bundle ACL reconstruction patients: a comparative study using pre- and postoperative MR images

PURPOSE

The purpose of this study was to evaluate the changes in the site-specific cartilage status after a double-bundle ACL reconstruction using preoperative and follow-up MR images.

METHODS

Thirty-six knees that underwent a double-bundle ACL reconstruction from 2001 to 2009 with the available preoperative and follow-up magnetic resonance imaging were included. Patients with a meniscal injury were compared with those without a meniscal injury. The cartilage morphology was classified using a 6-grade scale [from 0 = normal thickness and signal, to 6 = diffuse full-thickness loss (>75 % of the region)]. The changes in cartilage status were evaluated at 14 sites.

RESULTS

Cartilage changes were observed in all sites and were classified according to the site and degree of change. The majority of changes were grade 0 and 1, which accounted for 68 and 16.8 % of changes, respectively. The patella medial facet and anterolateral and centromedial femoral regions showed significantly more cartilage loss than the posteromedial, centrolateral, anterolateral, and anteromedial tibial regions. No significance was observed between the knees with or without combined injuries (n.s.). On the other hand, knees with or without combined injuries showed a different pattern of cartilage change, as demonstrated by different levels of grade change at sites.

CONCLUSIONS

The change in cartilage status was minimal after a double-bundle ACL reconstruction. The patella medial facet, lateral femur anterior region, and medial femur central region showed significantly more cartilage loss than the medial tibia posterior, lateral tibia central, lateral tibia anterior, and medial tibia anterior regions. The presence of a combined injury did not affect the cartilage status changes, even though it was underpowered and too short term to assess the influence of the meniscal injury.

LEVEL OF EVIDENCE

Case series, Level IV.

Femoral graft bending angle and femoral tunnel geometry of transportal and outside-in techniques in anterior cruciate ligament reconstruction: an in vivo 3-dimensional computed tomography analysis

PURPOSE

To compare femoral graft bending angles and femoral tunnel geometries between the transportal (TP) and outside-in (OI) techniques after anatomic double-bundle (DB) anterior cruciate ligament (ACL) reconstruction.

METHODS

Thirty-nine patients underwent DB ACL reconstruction with the TP and OI techniques. They were randomized on the day of surgery to either the TP group (group I, 21 cases) or the OI group (group II, 18 cases). Femoral graft bending angle, femoral tunnel geometry, posterior wall breakage, and tunnel communication were assessed by computed tomography imaging with OsiriX imaging software (Pixmeo, Geneva, Switzerland).

RESULTS

The mean anteromedial (AM) and posterolateral (PL) femoral graft bending angles of group II (97.3° ± 8.3° and 97.4° ± 8.6°, respectively) were significantly more acute than those of group I (108.2° ± 8.4° and 109.9° ± 8.8°, respectively) (P < .001). The mean AM femoral tunnel length of group II (34.3 ± 3.9 mm) was significantly longer than that of group I (31.9 ± 2.7 mm) (P = .02). However, the mean PL femoral tunnel lengths did not differ between groups. In 7 cases-4 cases (19.0%) in group I and 3 cases (16.6%) in group II-the femoral tunnel communication was found around the intra-articular aperture. Posterior wall breakage was observed in 5 cases (23.8%), which were all in AM femoral tunnels of group I.

CONCLUSIONS

The OI technique resulted in more acute femoral graft bending angles (difference of 10.9° and 12.5° for AM and PL, respectively) and longer mean AM femoral tunnel lengths (difference of 2.4 mm) than the TP technique after anatomic DB ACL reconstruction, even though these small differences might be unlikely to be of clinical significance. Femoral tunnel communication was found in both groups, and posterior wall breakage was observed in AM femoral tunnels with the TP technique.

LEVEL OF EVIDENCE

Level I, prospective randomized trial.

Analysis of tunnel widening after double-bundle ACL reconstruction

PURPOSE

The purpose of this study was to evaluate the tunnel widening using a multi-planar reformation of MRI (Magnetic Resonance Imaging) in the orientation of the tunnel. The hypotheses of this study were as follows: (1) tunnel widening would be reduced with the above-mentioned technique, (2) the degree of tunnel widening would be different at the site of the tunnels, and (3) the time interval from surgery to MRI acquisition would affect the magnitude of tunnel widening.

METHODS

Forty double-bundle ACL reconstructed patients who underwent postoperative MRI were enrolled in this study. The postoperative MRI was performed at 26.7 ± 7.4 months in terms of time. The tunnel widening was examined using a multi-planar reformation of MRI in the orientation of the tunnel. Site-specific analysis was performed according to the depth (the entrance, mid, and exit portion) and wall (anterior, posterior, medial, and lateral walls). The correlation between MRI and widening was also evaluated.

RESULTS

The mean tunnel widening of the femoral AM (Anteromedial), femoral PL (Posterolateral), tibial AM, and tibial PL in terms of the most widened diameter was 1.9 (25.4), 2.1 (30.8), 2.5 (32.8), and 3.2 mm (44.5%), respectively. The tibial PL tunnel showed significant widening than the other tunnels. At the entrance, tunnel widening occurred mostly, followed by the order of the mid and exit portion. Correlation analysis of the time interval of MRI acquisition and tunnel widening showed little association.

CONCLUSIONS

Tunnel widening after a double-bundle ACL reconstruction using an outside-in technique with press-fitting of the graft was acceptable compared to previously published studies. The tibial PL tunnel showed the most widening among the 4 tunnels examined with the tunnel entrance being most widened area.

LEVEL OF EVIDENCE

Therapeutic case series, Level IV.

Comparative analysis of femoral tunnels between outside-in and transtibial double-bundle anterior cruciate ligament reconstruction: a 3-dimensional computed tomography study

PURPOSE

The objectives of this study were (1) to compare locations of the femoral tunnels created by outside-in and transtibial techniques and the reference data and (2) to compare the diameter of the tunnel entrance based on the real reaming size.

METHODS

A comparative study was performed with 20 outside-in and 22 transtibial double-bundle anterior cruciate ligament reconstruction patients. Computed tomography scans of the operated knees of the outside-in and transtibial groups were performed at 1.25 days (range, 1 to 3 days) and 2.7 weeks (range, 3 days to 4 weeks), respectively. Three-dimensional surface models were then produced. For all 3 plane data sets, the positions of the femoral tunnels were measured by an anatomic coordinate axis method. For comparison of the tunnel diameter at the entrance of tunnel, the difference between the real reaming and measured diameter was determined first on computed tomography images. Subsequently, the differences in the outside-in and transtibial techniques were compared.

RESULTS

In the comparison between outside-in and reference data, the posterior-anterior direction of the posterolateral (PL) tunnel showed an anterior position compared with reference data, even though it was positioned more posteriorly compared with that of the transtibial technique (P = .003). In the comparison between transtibial and reference data, the posterior-anterior direction of the anteromedial (AM) and PL tunnels showed an anterior position compared with reference data (P = .019 and P = .005, respectively). The transtibial technique showed significantly larger diameters in both AM and PL tunnels (P < .001 and P < .001, respectively).

CONCLUSIONS

The outside-in technique showed more accurate replication of the femoral tunnels than the transtibial technique, particularly the AM tunnel of the femur. The transtibial technique showed an ellipsoidal tunnel configuration at the entrance of the tunnel, which suggests that eccentric reaming is unavoidable because the reaming angle is determined by the tibial tunnel.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Effect of fatigue on tibial rotation after single- and double-bundle anterior cruciate ligament reconstruction: a 3-dimensional kinematic and kinetic matched-group analysis

BACKGROUND

Fatigue is an extrinsic factor adversely affecting joint proprioception and neuromuscular response, thereby increasing anterior cruciate ligament (ACL) strain and injury risk. The effectiveness of the single- and double-bundle techniques for ACL reconstruction to control residual rotational knee laxity under fatigue has not been examined.

HYPOTHESIS

Fatigue results in a significant increase in tibial rotation angles and moments in both ACL-intact and single- and double-bundle ACL-reconstructed knees. The 2 groups with ACL-reconstructed knees will show no significant differences in tibial rotation angles and moments either pre- or postfatigue.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty-four male patients who underwent successful single-bundle (n = 12) or double-bundle (n = 12) ACL reconstructions and 10 matched healthy controls were subjected to a standard lower limb muscle fatigue protocol using an isokinetic dynamometer. Three-dimensional motion analysis was used to measure tibial rotation and rotational knee moments in the pre- and postfatigue states, during a swinging maneuver on the weightbearing leg from a standing position with the knee in extension.

RESULTS

Tibial rotation of the single-bundle group significantly increased postfatigue (prefatigue 22° ± 10° vs 29° ± 15° postfatigue, P = .015). In contrast, the double-bundle group showed similar tibial rotation values pre- and postfatigue (16° ± 6° vs 18° ± 4°, P = .22). The double-bundle group showed a trend toward decreased tibial rotation values pre- and post-fatigue compared with controls (22 ± 4 and 23 ± 4) (P = .065 and .08, respectively). In the prefatigue state, rotational moments (N·mm/Kg) of the single-bundle (339 ± 148) and double-bundle (317 ± 97) groups were significantly lower than that of controls (465 ± 134) (P = .05 and .03, respectively). In the postfatigue state, an increase was observed in rotational moments of the single-bundle (388 ± 131) and double-bundle (408 ± 187) groups compared with prefatigue values, whereas a decrease was noted in the control group (411 ± 117).

CONCLUSION

Single-bundle ACL-reconstructed knees demonstrate a reduced ability to resist rotational loads under fatigue. Double-bundle reconstructed knees had significantly better control of tibial rotation when fatigued. However, they demonstrate an excessive, yet not significant, reduction in tibial rotation compared with the intact knee, suggesting a possible overcorrection in rotational laxity.

Is femoral tunnel length correlated with the intercondylar notch and femoral condyle geometry after double-bundle anterior cruciate ligament reconstruction using the transportal technique? An in vivo computed tomography analysis

PURPOSE

To analyze femoral tunnel geometry using computed tomography (CT) imaging and evaluate the anatomic factors affecting femoral tunnel length after anterior cruciate ligament (ACL) reconstruction by the transportal technique.

METHODS

Twenty-nine patients underwent an anatomic double-bundle ACL reconstruction with a femoral tunnel drill by the transportal technique. CT imaging with OsiriX software (version 3.8; Pixmeo, Geneva, Switzerland) was used to measure femoral tunnel length (anteromedial [AM], posterolateral [PL], and central), femoral tunnel divergent angle, and femoral condyle size and intercondylar notch size parameters. Correlations between femoral tunnel length and femoral condyle size and intercondylar notch size parameters were analyzed.

RESULTS

The mean AM, PL, and central femoral tunnel lengths were 33.3 ± 3.9 mm, 33.6 ± 3.6 mm, and 34.3 ± 3.2 mm, respectively. A femoral tunnel length of less than 30 mm developed in 7 cases (24.1%) in the AM aspect and 4 cases (13.8%) in the PL aspect. The mean femoral tunnel divergent angle was 14.4° ± 4.1°. A positive correlation was found between AM, not PL or central, femoral tunnel length and medial femoral condyle anteroposterior (AP) distance (P = .01, r = 0.46), lateral femoral condyle AP distance (P = .01, r = 0.43), medial-to-lateral epicondylar distance (P = .03, r = 0.39), middle notch width (P = .009, r = 0.47), notch height (P = .001, r = 0.57), and notch area (P < .001, r = 0.58).

CONCLUSIONS

After double-bundle ACL reconstruction with the transportal technique through the accessory anteromedial portal, the AM and PL femoral tunnels showed mean tunnel length greater than 30 mm and a divergent angle. However, a femoral tunnel length of less than 30 mm developed in some cases. AM femoral tunnel length was correlated with femoral condyle size (medial femoral condyle AP distance, lateral femoral condyle AP distance, and medial-to-lateral epicondylar distance) and intercondylar notch size (notch width, notch height, and notch area).

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

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.

Comparisons of femoral tunnel enlargement in 169 patients between single-bundle and anatomic double-bundle anterior cruciate ligament reconstructions with hamstring tendon grafts

PURPOSE

Authors have hypothesized that the incidence and the degree of femoral tunnel enlargement after the hamstring ACL reconstruction may be significantly less in the anatomic double-bundle procedure than in single-bundle procedure. The purpose of this study is to test this hypothesis.

METHODS

Seventy-two patients who underwent single-bundle reconstruction (Group S) and 97 patients who underwent anatomic double-bundle reconstruction (Group D) were followed up for 2 years after surgery. The hamstring tendon grafts were used in each procedure. All of the 169 patients were examined with computed radiography, and the standard clinical evaluation methods.

RESULTS

In Group S, the incidence of femoral tunnel enlargement was 48.6 and 54.2% in the anteroposterior and lateral views. In Group D, the incidence of femoral anteromedial and posterolateral tunnel enlargement was 36.1 and 23.7%, respectively, in the anteroposterior view, and that of femoral anteromedial and posterolateral tunnel enlargement was 33.0 and 21.6%, respectively, in the lateral view. The incidence of femoral tunnel enlargement was significantly less in Group D than in Group S (P < 0.0133). Concerning the degree of the tunnel enlargement, a similar tendency with statistical significance was observed (P < 0.0001). In each group, there were no significant relationships between the degree of tunnel enlargement and each clinical measure.

CONCLUSION

Both the incidence and the degree of femoral tunnel enlargement after anatomic double-bundle reconstruction with the hamstring tendon grafts are significantly less than those after single-bundle reconstruction with the same graft.

LEVEL OF EVIDENCE

Prospective comparative cohort study, Level II.

Volumetric injury of the distal femoral physis during double-bundle ACL reconstruction in children: a three-dimensional study with use of magnetic resonance imaging

BACKGROUND

Double-bundle anterior cruciate ligament (ACL) reconstruction was developed to produce a more "anatomic" reproduction of the anteromedial and posterolateral bundles of the ACL. The purpose of this study was to determine the volume of injury to the physis during double-bundle ACL reconstruction in children with open physes.

METHODS

Magnetic resonance images (MRIs) of ten knees of children were converted into three-dimensional models. Computer-aided design/computer-aided manufacturing software placed drill-holes of 6, 7, 8, and 9 mm in diameter in these models, simulating tunnels in the femur used for anatomic double-bundle ACL reconstruction. Computer-aided design/computer-aided manufacturing software was used to calculate the total physeal volume and the volume of physis that was removed by creation of the tunnels. The ratio of the physeal volume that had been removed to the total physeal volume was subsequently determined.

RESULTS

With use of 6, 7, 8, and 9-mm-diameter drill-holes in the femur, the average physeal volume removed, as a percentage of the total physeal volume, was 1.5%, 2.0%, 2.5%, and 2.9%, respectively, for the anteromedial tunnels; 2.2%, 2.9%, 3.6%, and 4.2% for the posterolateral tunnels; and 3.7%, 4.8%, 5.7%, and 6.5% for the anteromedial and posterolateral tunnels combined. The volume of physeal damage caused by the posterolateral drill-holes was greater than that produced by the anteromedial drill-holes in all subjects.

CONCLUSIONS

Drill-hole placement during ACL reconstruction produces a zone of physeal injury. Double-bundle techniques substantially increase the volume of injury to the physis, which appears to increase the risk of abnormal growth in the distal femoral physis following this surgical procedure.

ACL injury and reconstruction: Clinical related in vivo biomechanics

Several researchers including our group have shown that knee joint biomechanics are impaired after anterior cruciate ligament (ACL) injury, in terms of kinematics and neuromuscular control. Current ACL reconstruction techniques do not seem to fully restore these adaptations. Our research has demonstrated that after ACL reconstruction, excessive tibial rotation is still present in high-demanding activities that involve both anterior and rotational loading of the knee. These findings seem to persist regardless of the autograft selection for the ACL reconstruction. Our results also suggest an impairment of neuromuscular control after ACL reconstruction, although muscle strength may have been reinstated. These abnormal biomechanical patterns may lead to loading of cartilage areas, which are not commonly loaded in the healthy knee and longitudinally can lead to osteoarthritis. Muscle imbalance can also influence patients' optimal sports performance exposing them to increased possibility of knee re-injury. In this review, our recommendations point towards further experimental work with in vivo and in vitro studies, in order to assist in the development of new surgical procedures that could possibly replicate more closely the natural ACL anatomy and prevent future knee pathology.