A matched pairs comparison of single- versus double-bundle anterior cruciate ligament reconstructions, clinical results and manual laxity testing

In Vitro Assessment of Knee Joint Biomechanics Using a Virtual Anterior Cruciate Ligament Reconstruction

Understanding the biomechanical impact of injuries and reconstruction of the anterior cruciate ligament (ACL) is vital for improving surgical treatments that restore normal knee function. The purpose of this study was to develop a technique that enables parametric analysis of the effect of the ACL reconstruction (ACLR) in cadaver knees, by replacing its contributions with that of a specimen-specific virtual ACLR that can be enabled, disabled, or modified. Twelve ACLR reconstructed knees were mounted onto a motion simulator. In situ ACLR graft forces were measured using superposition, and these data were used to design specimen-specific virtual ACLRs that would yield the same ligament force-elongation behaviors. Tests were then repeated using the virtual ACLR in place of the real ACLR and following that in ACL deficient knee by disabling the virtual ACLR. In comparison to the ACL deficient state, the virtual ACLRs were able to restore knee stability to the same extent as real ACLRs. The average differences between the anterior tibial translation (ATT) of the virtual ACLR versus the real ACLR were +1.6 ± 0.9 mm (p = 0.4), +2.1 ± 0.4 mm (p = 0.4), and +1.0 ± 0.9 mm (p = 0.4) during Anterior drawer, Lachman and Pivot-shift tests, respectively, which is small in comparison to the full ATT range of motion (ROM) of these knees. Therefore, we conclude that a virtual ACLR can be used in place of real ACLR during biomechanical testing of cadaveric knees. This capability opens the door for future studies that can leverage parameterization of the ACLR for surgical design optimization.

A Study of the Functional Outcome of Supplementation of Hamstring Graft With Anterior Half of the Peroneus Longus Tendon in Arthroscopic Anterior Cruciate Ligament Reconstruction

INTRODUCTION

The present study was done to analyze the functional outcome, donor site morbidities, and associated parameters when using the anterior half of the peroneus longus for augmentation of an inadequate hamstring graft when performing arthroscopic anterior cruciate ligament (ACL) reconstruction.

METHODS

Thirty patients with complete ACL tears were operated on. In all these patients, the thickness or length of the hamstring graft taken was found to be inadequate (less than 8 mm and 7.5 cm, respectively). So, additionally, the anterior half of the peroneus longus tendon (AHPLT) graft was harvested to reach an optimum size of the final graft. Functional outcome was assessed using the International Knee Documentation Committee (IKDC) score at six weeks, three months, and six months. The Foot and Ankle Disability Index (FADI) score at six months was used to assess ankle stability.

RESULTS

The mean age in our study was 28.8 years with male predominance (73.33%). The mean operative time was 86.4 minutes. The mean hamstring graft thickness in our study was 6.5 mm, which improved to 9.12 mm after augmentation. The mean graft length after AHPLT augmentation was 9.38 cm. The mean IKDC score at six months was 87.35. At the end of six months, FADI scores were found within normal limits (range: 135-136) in all the patients. No complications were noted in any of the patients.

CONCLUSION

The AHPLT graft was always found to be sufficient enough for augmenting the hamstring graft to reach an acceptable thickness and length. There was no graft site morbidity and the ankle functional levels remained the same as preoperative levels, making it an excellent choice for augmentation of inadequate hamstring grafts.

Local variations in mechanical properties of human hamstring tendon autografts for anterior cruciate ligament reconstruction do not translate to a mechanically inferior strand

A ruptured anterior cruciate ligament (ACL) is often reconstructed with a multiple-strand autograft of a semitendinosus tendon alone or combined with a gracilis tendon. Up to 10% of patients experience graft rupture. This potentially results from excessive local tissue strains under physiological loading which could either result in direct mechanical failure of the graft or induce mechanobiological weakening. Since the original location in the hamstring tendon cannot be traced back from an autograft rupture site, this study explored whether clinical outcome could be further improved by avoiding specific locations or regions of human semitendinosus and/or gracilis tendons in ACL grafts due to potential mechanical or biochemical inferiority. Additionally, it examined numerically which clinically relevant graft configurations experience the lowest strains - and therefore the lowest rupture risk - when loaded with equal force. Remnant full-length gracilis tendons from human ACL reconstructions and full-length semitendinosus- and ipsilateral gracilis tendons of human cadaveric specimens were subjected to a stress-relaxation test. Locations at high risk of mechanical failure were identified using particle tracking to calculate local axial strains. As biochemical properties, the water-, collagen-, glycosaminoglycan- and DNA content per tissue region (representing graft strands) were determined. A viscoelastic lumped parameter model per tendon region was calculated. These models were applied in clinically relevant virtual graft configurations, which were exposed to physiological loading. Configurations that provided lower stiffness - i.e., experiencing higher strains under equal force - were assumed to be at higher risk of failure. Suitability of the gracilis tendon proper to replace semitendinosus muscle-tendon junction strands was examined. Deviations in local axial strains from the globally applied strain were of similar magnitude as the applied strain. Locations of maximum strains were uniformly distributed over tendon lengths. Biochemical compositions varied between tissue regions, but no trends were detected. Viscoelastic parameters were not significantly different between regions within a tendon, although semitendinosus tendons were stiffer than gracilis tendons. Virtual grafts with a full-length semitendinosus tendon alone or combined with a gracilis tendon displayed the lowest strains, whereas strains increased when gracilis tendon strands were tested for their suitability to replace semitendinosus muscle-tendon junction strands. Locations experiencing high local axial strains - which could increase risk of rupture - were present, but no specific region within any of the investigated graft configurations was found to be mechanically or biochemically deviant. Consequently, no specific tendon region could be indicated to provide a higher risk of rupture for mechanical or biochemical reasons. The semitendinosus tendon provided superior stiffness to a graft compared to the gracilis tendon. Therefore, based on our results it would be recommended to use the semitendinosus tendon, and use the gracilis tendon in cases where further reinforcement of the graft is needed to attain the desired length and cross-sectional area. All these data support current clinical standards.

Isolated lateral extra-articular tenodesis enhance better rotatory knee joint stability post-primary ACL repair: Four cases report and literature review

INTRODUCTION AND IMPORTANCE

Residual rotatory instability has been reported to occur after primary anterior cruciate ligament reconstruction. The anterolateral ligament complex of the knee has gained attention for its role in rotational instability of the knee, especially in association with anterior cruciate ligament injuries. The role of an isolated lateral extra-articular tenodesis procedure among those patients presenting with residual rotatory instability after primary anterior cruciate ligament reconstruction has not been reported on.

CASE PRESENTATION

Four patients (Tegner level 4) presenting with residual rotatory instability after primary anterior cruciate ligament reconstruction without signs of graft failure, underwent an isolated lateral extra-articular tenodesis with modified Lemaire procedure. Pre- and postoperative outcome scores were assessed. At one-year follow-up, all patients reported functional knee stability. Pivot shift tests were negative and postoperative Lysholm scores were increased with a mean of 19.75 points. Tegner scores equaled the preinjury level.

CLINICAL DISCUSSION

This case report showed that our four patients where successfully treated with an isolated secondary modified Lemaire procedure for residual anterolateral rotatory instability after primary anterior cruciate ligament reconstruction.

CONCLUSION

An isolated secondary lateral extra-articular tenodesis procedure can be a valuable treatment option for moderate active patients with residual rotatory instability after a primary anterior cruciate ligament reconstruction without signs of graft failure.

Outcomes Following Arthroscopic Single and Double Bundle Anterior Cruciate Ligament (ACL) Reconstruction Supported by the Comprehensive Early Rehabilitation Program (CERP)

Background

The aim of this study was to compare the level of functional condition in patients who had rehabilitation with the comprehensive early rehabilitation program (CERP) following either single bundle (SB) or double bundle (DB) anterior cruciate ligament reconstruction (ACLR) using semitendinosus-gracilis tendon graft (ST-G) method. We hypothesized that 12 weeks after reconstruction followed by a rehabilitation program, there would be a difference in clinical results and functional activity between patients.

Material/Methods

This study included 94 patients who had rehabilitation with CERP after knee surgery for a knee injury from a recreational sport. There were 49 patients in Group 1 (mean age, 36.5 years) who had CERP after SB ACLR, and 45 patients in Group 2 (mean age, 35.6 years) who had CERP after DB ACLR. Functional condition was tested using the Lysholm Knee Scoring Scale, and knee stability was measured using KT-2000. The first examination was performed before CERP and the second examination was performed 12 weeks later.

Results

The level of functional condition in both groups was similar before rehabilitation with CERP, with no significant difference (P<0.958) and was considered relatively low. In the second examination, 12 weeks after starting CERP, the patients improved in both groups. The improvement was larger in the SB ACLR Group 1 than in the DB ACLR Group 2. The difference was significant (P<0.005). However, the patients in Group 2 achieved better knee stability scores in the KT-2000 examination than the patients in Group 1. The difference was significant (P=0.035).

Conclusions

We found that the patients from both groups after 12 weeks of CERP achieved an improvement in stability and functional activity within normal limits. However, SB ACLR was more effective than DB ACLR in terms of the level of functionality achieved with CERP but was less effective in terms of knee stability.

A fluoroscopic analysis of the length changes of the capsulo-osseous layer of the distal iliotibial band

PURPOSE

Previous studies have implicated the iliotibial band and its deeper capsulo-osseous layer as key restraints against internal rotation. However, the kinematic properties of the capsulo-osseous layer, throughout knee range of motion, are not currently known. Therefore, the purpose of this research was to quantify the length changes of this structure through various degrees of knee flexion.

METHODS

Ten cadaveric knee specimens were dissected to expose the capsulo-osseous layer of the iliotibial band. Radiopaque beads were embedded, at standardized increments, into the tissue and fluoroscopic images were taken from 0° to 105° of knee flexion in 15° increments. The positions of the beads were identified in each image and the length, width, and area changes of the capsulo-osseous layer were calculated. The data were analyzed as a percent change from 0° and compared across flexion angles using a repeated-measures analysis of variance (α = 0.05).

RESULTS

There was a significant increase in the length of the capsulo-osseous layer at flexion angles greater than 30°, with changes occurring primarily at the level of the femoral insertion. Meanwhile, non-homogenous decreases in width and area were found with increasing flexion angle. The distance between the capsulo-osseous layer insertion on the distal femur and proximal tibia significantly increased from 60° to 105°; maximal changes occurred at 105° [9.64 (4.12) %, p = 0.003].

CONCLUSIONS

The capsulo-osseous layer of the iliotibial band behaves in a non-isometric fashion and this work suggests that tensioning and fixation should occur between 75° and 105° of flexion, if repair or reconstruction is indicated.

[Research progress of double-bundle anterior cruciate ligament reconstruction in adolescents]

OBJECTIVE

To review the advances in double-bundle anterior cruciate ligament (ACL) reconstruction in adolescents at home and abroad.

METHODS

Recent literature about double-bundle ACL reconstruction in adolescents at home and abroad was extensively consulted, and the relationship between bone canal and epiphyseal plate, clinical verification of surgical safety, and clinical effectiveness of double-bundle ACL reconstruction in adolescents were summarized and analyzed.

RESULTS

Double-bundle ACL reconstruction has certain advantages in clinical stability and re-rupture rate when compared with single-bundle ACL reconstruction in adolescents, and there is no significant difference in safety between them.

CONCLUSION

Double-bundle ACL reconstruction in adolescents can achieve lower re-rupture rate and better stability when compared with single-bundle reconstruction. However, the sample size of clinical research is too small, and the follow-up time is too short, so the effectiveness needs to be continuously observed.

The Anterolateral Complex of the Knee

Background:

Significant controversy exists regarding the anterolateral structures of the knee.

Purpose:

To determine the layer-by-layer anatomic structure of the anterolateral complex of the knee.

Study Design:

Descriptive laboratory study.

Methods:

Twenty fresh-frozen cadaveric knees (age range, 38-56 years) underwent a layer-by-layer dissection to systematically expose and identify the various structures of the anterolateral complex. Quantitative measurements were performed, and each layer was documented with high-resolution digital imaging.

Results:

The anterolateral complex of the knee consisted of different distinct layers, with the superficial and deep iliotibial band (ITB) representing layer 1. The superficial ITB had a distinct connection to the distal femoral metaphysis and femoral condyle (Kaplan fibers), and the deep layers of the ITB were identified originating at the level of the Kaplan fibers proximally. This functional unit, consisting of the superficial and deep ITB, was reinforced by the capsulo-osseous layer of the ITB, which was continuous with the fascia of the lateral gastrocnemius and biceps femoris muscles. These 3 components of the ITB became confluent distally, and the insertion spanned from the Gerdy tubercle anteriorly to the lateral tibia posteriorly on a small tubercle (lateral tibial tuberosity). Layer 3 consisted of the anterolateral capsule, in which 35% (7/20) of specimens had a discreet mid-third capsular ligament.

Conclusion:

The anterolateral complex consists of the superficial and deep ITB, the capsulo-osseous layer of the ITB, and the anterolateral capsule. The anterolateral complex is defined by the part of the ITB between the Kaplan fibers proximally and its tibial insertion, which forms a functional unit. A discrete anterolateral ligament was not observed; however, the anterolateral ligament described in recent studies likely refers to the capsulo-osseous layer or the mid-third capsular ligament.

Clinical Relevance:

The anterolateral knee structures form a complex functional unit. Surgeons should use caution when attempting to restore this intricate structure with extra-articular procedures designed to re-create a single discreet ligament.

The evolution of primary double-bundle ACL reconstruction and recovery of early post-operative range of motion

PURPOSE

The aim of this study was to analyse early post-operative range of motion (ROM) as our anatomic double-bundle (DB) anterior cruciate (ACL) reconstruction technique with respect to tunnel placement evolved. It is the hypothesis of this study that more anatomic placement of the femoral insertion site of the anteromedial (AM) bundle of the ACL results in better restoration of early post-operative knee range of motion.

METHODS

Two methods of DB ACL reconstruction regarding more accurate placement of the femoral AM tunnel in relation to its anatomic origin were compared. Patients presenting for 1- and 3-month post-operative clinical visits were examined for passive extension and active flexion by members of the clinical staff. Only patients undergoing primary DB reconstruction with allograft were included in the analyses. To determine the effects of the modified AM bundle placement on recovery of post-operative ROM, patients undergoing surgery in the 6 months before July 2006 (Group A, n = 50) were compared to patients undergoing surgery in the 6 months after July 2006 (Group B, n = 49).

RESULTS

A total of 99 patients met the inclusion criteria. More accurate placement of the AM bundle of the ACL was associated with a smaller side-to-side difference in flexion at 1 month (n.s.) and at 3 months (3° reduction, p < 0.03) after surgery. There was no effect on extension (n.s.) CONCLUSION: More anatomic placement of the femoral insertion of the AM bundle was associated with improved knee flexion. The study translates the findings of previous anatomic basic science research to demonstrate improved restoration of normal joint motion. This ideally leads to improved long-term clinical outcomes and maintenance of joint and cartilage health.

LEVEL OF EVIDENCE

III.

Comparison of outcome after anatomic double-bundle and antero-medial portal non-anatomic single-bundle reconstruction in ACL-injured patients

PURPOSE

The aim of this study was to compare anatomic double-bundle anterior cruciate ligament reconstruction with non-anatomic single-bundle reconstruction.

METHODS

In a prospective consecutive series, 94 unselected patients [45 anatomic double-bundle (ADB) and 49 non-anatomic single-bundle (SB)] underwent ACL reconstruction involving hamstring tendon autograft, interference screw fixation on both the femoral and tibial side and drilling the femoral tunnel(s) through the antero-medial portal in both groups. In the ADB group, the remnants of the ACL were identified and the grafts were placed anatomically. In the SB group, traditional placement of the graft was performed in a less anatomic manner. Pre-operatively, the groups were comparable in terms of age, gender, time between injury and operation and associated injuries. One independent physiotherapist performed all the pre-operative and post-operative assessments.

RESULTS

The follow-up period was 26 (22-34) and 24 (23-30) months in the ADB and SB groups, respectively (p = 0.005). At follow-up, 78 % in the ADB group and 74 % in the SB group had a negative pivot-shift test (n.s.). The KT-1000 134N measurements were 2 (-5 to 10.5) and 2 (-4 to 7) mm in the ADB and SB groups, respectively (n.s.). At follow-up, the extension deficit was significantly larger in the ADB group than in the SB group (p = 0.001). The Tegner activity scale was significantly higher in the ADB group both pre-operatively and at follow-up (p = 0.03 and p = 0.004). In overall terms, both groups had improved significantly at the two-year follow-up.

CONCLUSION

In an unselected group of ACL-injured patients, anatomic double-bundle reconstruction did not result in better rotational or antero-posterior stability measurements than antero-medial portal non-anatomic single-bundle reconstruction at the two-year follow-up.

LEVEL OF EVIDENCE

III.

Single-bundle versus double-bundle anterior cruciate ligament reconstruction: A comparative study with propensity score matching

BACKGROUND

Numerous studies have elucidated the functional anatomy and biomechanics of the anterior cruciate ligament (ACL), as a result, double-bundle (DB) ACL reconstruction has received much attention and has become a popular choice because it gives better rotational stability. Many other studies, however, found no differences with respect to stability, and/or other clinical outcomes between the DB and single-bundle (SB) techniques. There is still not enough evidence as to whether the anatomical DB anterior cruciate ligament reconstruction (ACLR) is superior to anatomical SB reconstruction. The purpose of this study is to compare various clinical and functional outcomes between SB and DBACLR at 2 years followup.

MATERIALS AND METHODS

Medical records of patients with ACLR available for at least 2 years followup were reviewed retrospectively. 191 patients (164 males and 25 females) for SB and 48 patients (40 males and 8 females) for DB were selected using the inclusion and exclusion criteria. The mean age of SB and DB was 29.9 and 24.8 years, respectively. Propensity score (PS) was calculated based on age, sex and Tegner activity score and 48 patients in each group were matched by the PS. Lysholm score, International Knee Documentation Committee (IKDC) subjective knee score and Tegneractivity score were investigated. Functional performance tests, isokinetic muscle strength test with Biodex system, pivot shift test and KT-2000 arthrometer test were performed.

RESULTS

At 2 years followup, there were no significant differences between SB and DB group in Lysholm score (92.9 vs. 90.6, P = 0.224), IKDC subjective knee score (88.7 vs. 87.0, P = 0.524), Tegner activity score (7.3 vs. 8.0, P = 0.059). No significant differences were also found in all functional performance tests, isokinetic muscle strength tests in 60° and 180°/s, KT-2000 arthrometer test and pivot shift test (P > 0.05).

CONCLUSIONS

There were no significant differences of clinical and functional outcomes between SB and DB ACLR at 2 years followup.

A systematic review of single- versus double-bundle ACL reconstruction using the anatomic anterior cruciate ligament reconstruction scoring checklist

PURPOSE

The aim of this systematic review was to apply the anatomic ACL reconstruction scoring checklist (AARSC) and to evaluate the degree to which clinical studies comparing single-bundle (SB) and double-bundle (DB) ACL reconstructions are anatomic.

METHODS

A systematic electronic search was performed using the databases PubMed (MEDLINE), EMBASE and Cochrane Library. Studies published from January 1995 to January 2014 comparing SB and DB ACL reconstructions with clinical outcome measurements were included. The items from the AARSC were recorded for both the SB and DB groups in each study.

RESULTS

Eight-thousand nine-hundred and ninety-four studies were analysed, 77 were included. Randomized clinical trials (29; 38%) and prospective comparative studies (29; 38%) were the most frequent study type. Most studies were published in 2011 (19; 25%). The most commonly reported items for both SB and DB groups were as follows: graft type (152; 99%), femoral and tibial fixation method (149; 97% respectively), knee flexion angle during graft tensioning (124; 8%) and placement of the tibial tunnel at the ACL insertion site (101; 66%). The highest level of documentation used for ACL tunnel position for both groups was often one dimensional, e.g. drawing, operative notes or o'clock reference. The DB reconstruction was in general more thoroughly reported. The means for the AARSC were 6.9 ± 2.8 for the SB group and 8.3 ± 2.8 for the DB group. Both means were below a proposed required minimum score of 10 for anatomic ACL reconstruction.

CONCLUSIONS

There was substantial underreporting of surgical data for both the SB and DB groups in clinical studies. This underreporting creates difficulties when analysing, comparing and pooling results of scientific studies on this subject.

Anatomical "C"-shaped double-bundle versus single-bundle anterior cruciate ligament reconstruction in pre-adolescent children with open growth plates

PURPOSE

To analyse the clinical, rotational and radiological (MRI) results of paediatric anatomical "C-shaped" double-bundle (DB) anterior cruciate ligament (ACL) reconstruction with anteromedial and posteromedial bundle compared to single-bundle (SB) ACL reconstruction.

METHODS

Between 2008 and 2014, 57 consecutive patients received a paediatric ACL reconstruction with open physis and were allocated into two groups, according to the surgical procedure. Transepiphyseal SB technique was used until 2012 and DB consecutively thereafter. Follow-up consisted of a clinical evaluation with assessment of the International Knee Documentation Committee (IKDC) form, the Lysholm knee score, Tegner activity score, KT-1000 arthrometer evaluation, VAS Scores for satisfaction, MRI and testing of rotational stability using a robotic system.

RESULTS

The mean time from ACL reconstruction to follow-up was 48.1 ± 15.8 in the SB group (n = 17) and 23.1 ± 13.2 in the DB group (n = 16; p < 0.001). No differences were found in the subjective scores. Biomechanically, there were significant differences identified in the KT-1000 (p < 0.03) and total tibial axial rotation (p < 0.04) when evaluating the reconstructed knee only. Ten of 17 (59%) of the SB patients had a Joint Play Area within the acceptable range of the median healthy knee value compared to 100 % in the DB group. Decreased patient satisfaction was associated with increased total tibial axial rotation. No growth disturbance was observed. Overall, 98% of patients were reached and either examined or interviewed. Re-rupture rate was 3 of 21 (14.3%) for DB and 9 of 35 (25.7%) for SB. All but one re-ruptures (92%) happened in the first 16 postoperative months independent of technique.

CONCLUSIONS

The re-rupture rate after pre-adolescent ACL reconstruction is too high both historically and in this mixed cohort. Anatomical transepiphyseal DB ACL reconstruction with open physis may result in a reduction in this re-rupture rate, which may be related to a tighter control of the Joint Play Area. While subjective clinical results were similar between SB and DB, decreased patient satisfaction was associated with increased total tibial axial rotation in the entire cohort. Despite the need for two transepiphyseal tunnels in the DB technique, there did not appear to be an increased risk in growth plate disturbance. Transepiphyseal DB ACL reconstruction appears to be a reasonable alternative to current techniques in pre-adolescent children with an ACL rupture.

LEVEL OF EVIDENCE

IV.

Does Double-Bundle Anterior Cruciate Ligament Reconstruction Improve Postoperative Knee Stability Compared With Single-Bundle Techniques? A Systematic Review of Overlapping Meta-analyses

PURPOSE

Multiple meta-analyses of randomized controlled trials, the highest available level of evidence, have been conducted to determine whether double-bundle (DB) or single-bundle (SB) anterior cruciate ligament reconstruction (ACL-R) provides superior clinical outcomes and knee stability; however, results are discordant. The purpose of this study was to conduct a systematic review of meta-analyses comparing SB and DB ACL-R to discern the cause of the discordance and to determine which of these meta-analyses provides the current best available evidence.

METHODS

We evaluated available scientific support for SB as compared with DB ACL-R by systematically reviewing the literature for published meta-analyses. Data on patient clinical outcomes and knee stability (as measured by KT arthrometry and pivot-shift testing) were extracted. Meta-analysis quality was judged using the Oxman-Guyatt and Quality of Reporting of Meta-analyses systems. The Jadad algorithm was then applied to determine which meta-analyses provided the highest level of evidence.

RESULTS

Nine meta-analyses were included, of which 3 included Level I Evidence and 6 included both Level I and Level II Evidence. Most studies found significant differences favoring DB reconstruction on pivot-shift testing, KT arthrometry measurement of anterior tibial translation, and International Knee Documentation Committee objective grading. Most studies detected no significant differences between the 2 techniques in subjective outcome scores (Tegner, Lysholm, and International Knee Documentation Committee subjective), graft failure, or complications. Oxman-Guyatt and Quality of Reporting of Meta-analyses scores varied, with 2 studies exhibiting major flaws (Oxman-Guyatt score <3). After application of the Jadad decision algorithm, 3 concordant high-quality meta-analyses were selected, with each concluding that DB ACL-R provided significantly better knee stability (by KT arthrometry and pivot-shift testing) than SB ACL-R but no advantages in clinical outcomes or risk of graft failure.

CONCLUSIONS

The current best available evidence suggests that DB ACL-R provides better postoperative knee stability than SB ACL-R, whereas clinical outcomes and risk of graft failure are similar between techniques.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

Is double-bundle anterior cruciate ligament reconstruction superior to single-bundle? A comprehensive systematic review

PURPOSE

To describe current evidence on single- and double-bundle anterior cruciate ligament (ACL) reconstruction, in terms of differences in knee kinematics, functional outcomes, patient-reported outcomes and graft failures.

METHODS

An electronic search was made using PubMed (MEDLINE), EMBASE and Cochrane Library. Studies published from January 1995 to August 2011 were included, and an updated search was made in PubMed in July 2012. Therapeutic studies, level of evidence I-III, for isolated primary ACL tears written in English comparing single- and double-bundle reconstruction reporting clinical outcome were included. Quality appraisal based on Cochrane Collaboration's tool for assessing risk of bias was performed.

RESULTS

Of 7,154 potentially eligible studies, 60 papers were included (25 randomised controlled trials, 21 prospective comparative studies, 14 retrospective comparative studies), comprising 4,146 patients (2,072 single-bundle, 2,074 double-bundle). Minor differences were found between study types. An analysis of graft failures revealed fewer re-ruptures in double-bundle reconstruction than single-bundle, 19 and 44, respectively. Up to 45 % of the studies reported a superior outcome in double-bundle reconstruction in terms of antero-posterior laxity, measured with the Lachman, anterior drawer, KT-1000/2000 and navigation. Measurements of rotatory laxity revealed superior results in double-bundle reconstruction measured with pivot shift and navigation in 18/42 (8/15 anatomically reconstructed) and 9/20 studies, respectively. Patient-reported outcome measures and functional outcomes did not differ to a large extent; however, differences when identified were almost exclusively in favour of double-bundle reconstruction.

CONCLUSION

Based on current evidence, double-bundle reconstruction appears to have fewer re-ruptures and less antero-posterior and rotatory laxity. Furthermore, no differences were found in short-term patient-reported outcome measures or objective findings. However, detailed statistical analyses of the included studies divided into homogeneous groups are needed to avoid reporting bias and to confirm any statistical difference.

Single-bundle or double-bundle for anterior cruciate ligament reconstruction: a meta-analysis

PURPOSE

To compare the clinical outcomes of anterior cruciate ligament (ACL) reconstruction with double-bundle and single-bundle techniques.

STUDY DESIGN

Meta-analysis

METHODS

We searched electronic databases including PubMed, Embase, Cochrane Central Register of Controlled Trials, and Google Scholar from 1966 to Jan 2012 to identify randomized controlled trials (RCTs) comparing clinical outcomes of anterior cruciate ligament (ACL) reconstruction with double-bundle and single-bundle techniques. Two reviewers independently extracted data and assessed trial quality. Meta-analysis was performed to pool results.

RESULTS

Nineteen RCTs were included with a total of 1686 patients. The pooled analysis across all studies showed that the double-bundle ACL reconstruction technique could have significantly better outcomes in rotational laxity, as assessed by the pivot-shift test, KT grading and IKDC grading than the single-bundle techniques. We found no evidence of a difference in function measured by IKDC scores, KT arthrometer, Lysholm knee, or Tegner activity scores and complications after operations between single and double-bundle ACL reconstruction groups.

CONCLUSION

Our meta-analysis demonstrated the superiority of double-bundle over single-bundle anterior cruciate ligament reconstruction. The double-bundle ACL reconstruction technique has better outcomes in rotational laxity (pivot-shift test, KT grading and IKDC grading). However, for functional recovery, there was no significant difference between single-bundle and double-bundle reconstruction techniques.

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.

Double-bundle versus single-bundle anterior cruciate ligament reconstruction: a prospective randomized study with 5-year results

BACKGROUND

Surgical technique is essential in anterior cruciate ligament (ACL) reconstruction.

PURPOSE

This randomized 5-year study tested the hypothesis that double-bundle ACL reconstruction with hamstring autografts and aperture screw fixation has fewer graft ruptures and rates of osteoarthritis (OA) and better stability than single-bundle reconstruction.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Ninety patients were randomized: double-bundle ACL reconstruction with bioabsorbable screw fixation (DB group; n = 30), single-bundle ACL reconstruction with bioabsorbable screw fixation (SBB group; n = 30), and single-bundle ACL reconstruction with metallic screw fixation (SBM group; n = 30). The following evaluation methods were used: clinical examination, KT-1000 arthrometer measurement, and International Knee Documentation Committee (IKDC) and Lysholm knee scores. Additionally, radiographic evaluation was made by a musculoskeletal radiologist who was unaware of the patients' clinical and surgical data. A single orthopaedic surgeon performed all the operations, and clinical follow-up assessments were made in a blinded manner by an independent examiner.

RESULTS

Preoperatively, there were no differences between the groups. Eleven patients (7 in the SBB group, 3 in the SBM group, and 1 in the DB group) had a graft failure during the follow-up and went on to ACL revision surgery (P < .043). Of the remaining 79 patients, a 5-year follow-up was performed for 65 patients (20 in the DB group, 21 in the SBB group, and 24 in the SBM group) who had their grafts intact. At 5 years, there was no statistically significant difference in the pivot-shift or KT-1000 arthrometer tests. In the DB group, 20% of the patients had OA in the medial femorotibial compartment and 10% in the lateral compartment, while the corresponding figures were 33% and 18% in the single-bundle groups, again an insignificant finding. Further, no significant group differences were found in the knee scores.

CONCLUSION

The double-bundle surgery resulted in significantly fewer graft failures and subsequent revision ACL surgery than the single-bundle surgeries during the 5-year follow-up. Knee stability and OA rates were similar at 5 years. In view of the size of the groups, some caution should be exercised when interpreting the lack of difference in the secondary outcomes.

A new quantitative method for pivot shift grading

PURPOSE

The purposes of the study were to evaluate and to quantify the pivot shift phenomenon by using a small and easy to handle measuring device for pivot shift quantification.

METHODS

Twenty patients (forty knees) with primary torn anterior cruciate ligaments (ACL) were tested under anesthesia, graded by the examiner and by the device according to the IKDC classification [normal (0), glide (1), clunk (2), and gross (3)]. For the grading by the device, a femoral and a tibial miniature inertial sensor measured the acceleration and the angular velocities. Three parameters were used for pivot shift identification and quantification: (1) difference between the positive and negative acceleration peak value (a(diff)), (2) the maximum jerk (j(max)), and (3) the standard deviation (SD(a)) of the acceleration. The ratio between the ACL-deficient and the intact knees was calculated in order to normalize the data.

RESULTS

The pivot shift phenomenon could be identified, and all three parameters showed significant higher values in the ACL-deficient knees compared to the intact knees (p < 0.05). The grading by examiner did not significantly correlate with a(diff) (p = 0.38; r = 0.21), j(max) (p = 0.36; r = -0.22), SD(a) (p = 0.65; r = 0.11), and grading by the device (p = 0.62; r = 0.12).

CONCLUSIONS

The present study has shown that the quantification of the pivot shift test is practicable when inertial sensors are used. The results have shown that the subjective grading of the pivot shift test does not correlate well with objective quantification.

Can the pivot-shift be eliminated by anatomic double-bundle anterior cruciate ligament reconstruction?

PURPOSE

To assess the ability of anatomic double-bundle anterior cruciate ligament reconstruction in eliminating the pivot-shift phenomenon when identified by a quantitative measuring system (computer navigation or magnetic resonance imaging).

METHODS

Literature review. Medline, Google Scholar and Cochrane Reviews computerized databases research using the keywords "pivot-shift," "anterior cruciate ligament reconstruction" and "double bundle." Twelve (7 in vitro and 5 in vivo) studies met the inclusion criteria.

RESULTS

There was a wide variation in the absolute value of translation and rotation measured after anatomic double-bundle anterior cruciate ligament reconstruction. There were also differences in fixation methods, pivot-shift execution conditions, applied stresses during the pivot-shift, calculation methods and reference systems utilized by measurement systems.

CONCLUSIONS

The double-bundle reconstruction was shown to over-constrain the knee with respect to the intact value, especially closer to knee extension. This review demonstrated that anatomic double-bundle anterior cruciate ligament reconstruction is able to eliminate pathological translations and rotations during the pivot-shift phenomenon, as identified by quantitative measurement systems.

LEVEL OF EVIDENCE

Review of Level III studies, Level III.

Mechanical assessment of two different methods of tripling hamstring tendons when using suspensory fixation

PURPOSE

To investigate two different methods of suture fixation and tendon behaviour when using an Endobutton and a tripled tendon.

METHODS

Thirty bovine tendons and foam blocks were randomly allocated to three groups: group 1: The tendon was doubled through 40-mm Endobutton; group 2: Tripled tendon--whip-stitched with No. 2 Ultrabraid, passed through an Endobutton and third limb secured to the loop via seven knots; and group 3: Tripled tendon--whip-stitched with No. 2 Fibreloop and fixed as group 2. A tunnel matching the graft diameter was drilled through the block. The graft was passed through the tunnel and fixed with an interference screw. The constructs were cycled at 1 Hz from 10 to 50 N for 10 cycles followed by 50-250 N at 1 Hz for 500 cycles. Load-to-failure test was then carried out at a rate of 20 mm/min. A custom digital image capture technique was used to measure and calculate displacement, strain and stress. Statistical analysis was carried out using Kruskal-Wallis test and paired t test.

RESULTS

There was no statistical significant difference between ultimate tensile strength (UTS) (P = 0.35) and yield load (0.41) between the 3 groups. The mean displacement of the third tendon limb in group 2 was 4.8 mm and in group 3, 1.5 mm. Displacement was not statistically significant (P = 0.07). The mean stress in the third limb versus the doubled portion of tendon in group 2 was 0.4 ± 0.02 versus 4.8 ± 0.52 MPa and in group 3, 0.5 ± 0.03 versus 5.2 ± 0.52 MPa.

CONCLUSIONS

In this biomechanical study, there was no mechanical difference in the overall properties between a doubled and tripled tendon graft. Significant cyclic elongation occurred in the third limb of the tripled tendon in comparison with the doubled portioned. Further work is needed to determine whether these mechanical findings translate to clinical practice. Caution should be used when tripling hamstring grafts. In particular, tripling small grafts provides no biomechanical advantage immediately and possibly long term, thus potentially increasing the risk of failure.