Clinical outcomes of double- vs single-bundle anterior cruciate ligament reconstruction: a systematic review of randomized control trials

Bone Density Distribution Pattern in the Lateral Wall of the Femoral Intercondylar Notch: Implications for the Direct Insertion of the Femoral ACL Attachment

Background

The ideal position of the femoral bone tunnel in the anterior cruciate ligament (ACL) is controversial. The functional importance of the ACL fiber varies depending on where it is attached to the femur. Functionally important fibers can cause high mechanical stress on the bone, and the Wolff law predicts that bone mineral density will increase at high mechanical stress sites.

Purpose/Hypothesis

The purpose of this study was to use computed tomography imaging to determine the distribution pattern of bone density in the lateral intercondylar wall. It was hypothesized that the high-density area (HDA) of the lateral intercondylar wall would reflect the functional insertion of the ACL as reported in previous anatomic studies.

Study Design

Descriptive epidemiology study.

Methods

Data from 39 knees without ACL injuries were retrospectively collected. The HDA of the lateral intercondylar wall was defined as the region containing the top 10% of the radiodensity values. The shape of the HDA was approximated as an ellipse, and the quadrant method was used to determine the center of the ellipse. The association between the ratio of the minor axis to the major axis of the ellipse and background characteristics was investigated.

Results

According to the quadrant method, the center of the HDA ellipse was 33.6% in the deep-shallow direction and 23.4% in the high-low direction. The center of the ellipse was comparable to the anatomic center of the ACL footprint, as previously reported. The ratio of the minor axis to the major axis of the ellipse was 0.58 (95% CI, 0.54-0.62). There was a significant negative correlation between the ratio of the minor axis to the major axis of the HDA ellipse and the posterior tibial slope (r = -0.38, P = .02).

Conclusion

The center of the HDA ellipse was found to be similar to the anatomic center of the ACL footprint. Considering the mechanical stress responses in bone, the HDA of the lateral intercondylar wall has the potential to represent the ACL insertion, especially functional insertion.

Anatomical double-bundle anterior cruciate ligament reconstruction moderately improved tegner scores over the long-term: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

To assess the effects of anatomical double-bundle (DB) versus single-bundle (SB) for anterior cruciate ligament (ACL) reconstruction in skeletally mature patients with ACL injuries.

METHODS

MEDLINE, EMBASE, and CENTRAL were searched from inception to February 7, 2022 were screened for randomized controlled trials. The Anatomic Anterior Cruciate Ligament Reconstruction Checklist was used to categorize studies as anatomic. A random-effects meta-analysis was conducted, with pooled results being summarized using mean difference (MD). Risk of Bias (RoB) was assessed using the RoB 2.0 tool. Certainty of evidence was rated using GRADE.

RESULTS

A search of 1371 unique articles yielded eight eligible trials, representing 735 patients (360 DB, 375 SB) with mean (SD) age of 28.5 (2.86) years and follow-up of 52.1 (36.2) months. Most trials had moderate to low RoB. Overall, DB was not significantly better than SB on Lysholm scores (MD = 0.52, 95% CI, - 1.80-2.85, p = 0.66; moderate certainty) or subjective International Knee Documentation Committee (IKDC) scores (MD = - 0.40, 95% CI, - 4.35-3.55, p = 0.84; moderate certainty). Tegner scores were significantly higher in SB than DB in the intermediate term (MD = - 0.72, 95% CI, - 1.10 to - 0.34, p = 0.0002; high certainty), while significantly higher in DB relative to SB in the long-term (MD = 0.52, 95% CI, 0.02-1.03, p = 0.04; high certainty).

CONCLUSION

DB ACL reconstruction significantly improves Tegner scores relative to SB ACL reconstruction over the long-term (t ≥ 5 years). Intermediate term Tegner scores favour SB reconstruction. In both durations, there was no clinically significant difference based on the pre-specified minimal clinically important difference of 1.0 point. There were also no significant differences in IKDC or Lysholm scores. Surgeons should consider anatomical DB ACL reconstruction as a result of long-term improvement in patient-reported outcomes.

LEVEL OF EVIDENCE

I.

Rebranding the 'anatomic' ACL reconstruction: Current concepts

The anterior cruciate ligament (ACL) is a complex ribbon-like structure, which is approximately 3.5 times larger at the tibial and femoral insertions than at the midpoint. Accordingly, it is impossible to recreate with a single cylindrical graft. However, this has not stopped surgeons from using the term "anatomic" to describe multiple ACL reconstruction techniques inserting at a number of different locations within the original ACL footprint, causing confusion. The term "anatomic" should be discarded and replaced by an anatomic description of the tunnel placements on the tibia and femur. Current ACL reconstruction techniques cite anatomical studies that identified "direct and indirect fibres" of the ACL. The "direct fibres" bear 85-95% of the load and provide the main resistance to both anterior tibial translation and internal rotation/pivot shift. On the femur, these fibres insert in a line just posterior to the intercondylar ridge and comprise the portion of the ACL that surgeons should strive to restore. Placement of the graft just posterior to the intercondylar ridge creates a line of placement options from the anteromedial bundle to the "central" position and finally to the posterolateral bundle position. The authors prefer placing the femoral tunnel in the isometric anteromedial position and addressing a high-grade pivot shift at the IT-band with a lateral extra-articular tenodesis. As with the femoral tunnel, the native ACL footprint on the tibia is much larger than the ACL graft and thus can be placed in multiple "anatomic" locations. The authors prefer placement of the tibial tunnel in the anterior most position of the native footprint that does not cause impingement in the femoral notch. Additional research is needed to determine the ideal tunnel positions on the femur and tibia and validating the technique with patient outcomes. However, this cannot be accomplished without describing tunnel placement with specific anatomical locations so other surgeons can replicate the technique.

The Statistical Fragility of Single-Bundle vs Double-Bundle Autografts for ACL Reconstruction: A Systematic Review of Comparative Studies

Background:

The statistical significance of a given study outcome can be liable to small changes in findings. P values are common, but imperfect statistical methods to convey significance, and inclusion of the fragility index (FI) and fragility quotient (FQ) may provide a clearer perception of statistical strength.

Purpose/Hypothesis:

The purpose was to examine the statistical stability of studies comparing primary single-bundle to double-bundle anterior cruciate ligament reconstruction (ACLR) utilizing autograft and independent tunnel drilling. It was hypothesized that the study findings would be vulnerable to a small number of outcome event reversals, often less than the number of patients lost to follow-up.

Study Design:

Systematic review; Level of evidence, 2.

Methods:

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the authors searched PubMed for comparative studies and randomized controlled trials (RCTs) published in select journals, based on impact factor, between 2005 and 2020. Risk-of-bias assessment and methodology scoring were conducted for the included studies. A total of 48 dichotomous outcome measures were examined for possible event reversals. The FI for each outcome was determined by the number of event reversals necessary to alter significance. The FQ was calculated by dividing the FI by the respective sample size.

Results:

Of the 1794 studies screened, 15 comparative studies were included for analysis; 13 studies were RCTs. Overall, the mean FI and FQ were 3.14 (IQR, 2-4) and 0.050 (IQR, 0.032-0.062), respectively. For 72.9% of outcomes, the FI was less than the number of patients lost to follow-up.

Conclusion:

Studies comparing single-bundle versus double-bundle ACLR may not be as statistically stable as previously thought. Comparative studies and RCTs are at substantial risk for statistical fragility, with few event reversals required to alter significance. The reversal of fewer than 4 outcome events in a treatment group can alter the statistical significance of a given result; this is commonly less than the number of patients lost to follow-up. Future comparative study analyses might consider including FI and FQ with P values in their statistical analysis.

Double bundle ACL reconstruction leads to better restoration of knee laxity and subjective outcomes than single bundle ACL reconstruction

PURPOSE

The purpose of this meta-analysis is to compare arthroscopic single bundle (SB) and double bundle (DB) anterior cruciate ligament (ACL) reconstructions in the light of all available randomised controlled trials (RCTs). A meta-analysis of this well-researched topic was performed and subgroup analyses of the medial portal (MP) technique and the transtibial technique (TT) were added as a new idea. The hypothesis was that the DB technique is superior to the SB technique also in subgroup analyses of the MP and TT techniques.

METHODS

Instructions of the PRISMA checklist were followed. Systematic literature search from electronic databases, including PubMed, Cochrane library and Scopus was performed to find RCTs that compared the SB and DB techniques. Nine outcomes were used to compare these two techniques. Each study was assessed according to the Cochrane Collaboration's risk of bias tool and three subgroup analyses (minimum 2-years' follow-up, TT technique and MP technique) were performed.

RESULTS

A total of 40 studies were included in this meta-analysis. When analysing all the included studies, the DB technique was superior to the SB technique in KT-1000/2000 evaluation (p < 0.01), IKDC subjective evaluation (p < 0.05), Lysholm scores (p = 0.02), pivot shift (p < 0.01) and IKDC objective evaluation (p = 0.02). Similar results were also found in the subgroup analyses of minimum 2-years' follow-up and the TT technique. However, there were no differences between the two techniques in a subgroup analysis of the MP technique.

CONCLUSION

Generally, DB ACL reconstruction leads to better restoration of knee laxity and subjective outcomes than SB ACL reconstruction. The subgroup analysis of the MP technique revealed that surgeons can achieve equally as good results with both techniques when femoral tunnels are drilled through the medial portal.

LEVEL OF EVIDENCE

II.

Subjective assessment reported by patients shows differences between single-bundle and double-bundle anterior cruciate ligament reconstruction, systematic review and meta-analysis

To determine the functional recovery, active reincorporation, and anteroposterior and rotational stability of patients undergoing anterior cruciate ligament (ACL) reconstruction using arthroscopy techniques with simple-bundle (SB) or double-bundle (DB). The following databases were searched: PubMed, Embase (Elsevier platform), the Cochrane Central Register of Controlled Trials (Wiley platform), Web of Science, and CINAHL. Level I and II studies involving anterior cruciate ligament arthroscopy were included in the search. Records were screened by title and abstract and assessed the risk of bias of selected studies. Meta-analyses using RevMan 5.3 software were conducted on the following outcomes: knee functionality, objective measurements of knee stability, rotational knee stability and knee anterior stability, sports reincorporation, and subjective assessments. Twenty-four studies of patients undergoing ACL reconstruction were included in the qualitative and quantitative synthesis (1707 patients) for Lysholm score, Subjective International Knee Documentation Committee (IKDC) score, Tegner score, KT-1000/2000, Lachman test, Objective IKDC score, and Pivot-Shift test. A return to pre-injury level showed a significant decrease in the Lysholm score (mean difference, - 0.99; 95% CI - 1.71 to - 0.40; P = 0.007) and Tegner score (mean difference, - 0.07; 95% CI, - 0.13 to - 0.01; P = 0.02) at DB reconstruction, similar to the knee functionality outcome of the subjective IKDC score (mean difference - 1.42; 95% CI - 2.46 to - 0.38; P = 0.007). There is no clear or significant difference in clinical stability and knee function or in sports incorporation with the true difference occurring in the subjective assessment.

Interbundle Impingement Pressure in Individualized and Nonindividualized Double-Bundle Anterior Cruciate Ligament Reconstruction: A Cadaveric Study

Background:

Graft impingement is one of the main concerns in double-bundle anterior cruciate ligament reconstruction (DB-ACLR). Impingement between the anteromedial (AM) and posterolateral (PL) bundles has been postulated to cause graft deterioration or rerupture, but this has not been thoroughly investigated, and the interbundle impingement pressure (IIP) has not been well researched.

Purpose:

To determine the IIP between the AM and PL bundles in the native anterior cruciate ligament (ACL) and in DB-ACLR with individualized and nonindividualized double-tunnel placement.

Study Design:

Controlled laboratory study.

Methods:

A total of 30 fresh-frozen, nonpaired, human cadaveric knees were randomly divided into 3 groups of 10 knees: native intact ACL (NI group), DB-ACLR tunnel placement using the preserved remnant procedure (individualized reconstruction) (PR group), and DB-ACLR tunnel placement using the bony landmark procedure (nonindividualized reconstruction) (BL group). Pressure sensors were inserted between the AM and PL bundles. The knee was moved passively from full extension to full flexion, and the IIP between the 2 ACL bundles was measured every 15°. Similarly, the impingement pressure was measured between the ACL and intercondylar roof and between the ACL and posterior cruciate ligament (PCL).

Results:

No significant differences were found in the maximum, mean, or minimum ACL-roof and ACL-PCL impingement pressures among the 3 groups. The IIP significantly increased when the knee joint was flexed >120° in all 3 groups (P < .001). Compared with the other 2 groups, the BL group had significantly higher maximum and mean IIP throughout the range of knee movement (P < .001) and from maximum extension to 120° of flexion (P < .001). The BL group also had significantly higher minimum IIP than the other 2 groups when knee flexion was >120° (P < .001). No significant differences were seen in maximum, minimum, or mean IIP between the NI and PR groups.

Conclusion:

The PR procedure (individualized DB-ACLR) was more consistent with the interbundle biomechanical conditions of the native ACL, whereas the BL procedure (nonindividualized DB-ACLR) had higher maximum and mean IIP. The IIP was higher than the ACL–intercondylar roof or ACL-PCL pressures, and it increased significantly when knee flexion was >120°.

Clinical Relevance:

These data suggest that surgeons can perform individualized DB-ACLR using preserved remnants for tunnel placement as impingement-free DB-ACLR.

Risk factors for postoperative graft laxity without re-injury after double-bundle anterior cruciate ligament reconstruction in recreational athletes

BACKGROUND

Although high activity is a risk factor for graft failure after anterior cruciate ligament (ACL) reconstruction, the risk factors for postoperative laxity after ACL reconstruction in recreational athletes are unknown.

METHODS

We enrolled 91 patients (40 males, 51 females; mean age 29.2 years; mean follow-up 4.3 years) who scored ≤ 6 on the Tegner activity scale, underwent double-bundle ACL reconstruction between 2010 and 2018, and did not experience re-injury. In the stable group (75 patients, <3.0 mm side-to-side difference (SSD) in anterior translation, grade 0 or 1 pivot shift 1 year after surgery) and unstable group (16 patients, ≥3.0 mm SSD, ≥grade 2 pivot shift), multivariate logistic regression analyses adjusted for factors showing P ≤ 0.3 on univariate analysis assessed risk factors for graft laxity. Lysholm score and graft intensity on MRI (Howell grade) were compared at final follow-up.

RESULTS

Mean SSD in anterior translation was 0.7 mm (stable group) and 3.3 mm (unstable group). Pivot shift grades were 0 (88%) and 1 (12%) in the stable group, and 0 (12.5%), 1 (50%), and 2 (37.5%) in the unstable group. Multivariate regression analyses showed that younger age and knee hyperextension were significant risk factors for graft laxity (P = 0.018 and 0.0016; cutoffs 18 years old and 8°, respectively). Lysholm scores in both groups were comparable, but graft intensity on MRI demonstrated significantly worse Howell grade in the unstable group (P = 0.002).

CONCLUSION

Younger age and knee hyperextension were risk factors for postoperative graft laxity without re-injury in recreational athletes.

Anatomic single vs. double-bundle ACL reconstruction: a randomized clinical trial-Part 1: clinical outcomes

PURPOSE

Compare clinical outcomes of anatomic single-bundle (SB) to anatomic double-bundle (DB) anterior cruciate ligament reconstruction (ACLR). It was hypothesized that anatomic DB ACLR would result in better International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) scores and reduced anterior and rotatory laxity compared to SB ACLR.

METHODS

Active individuals between 14 and 50 years of age that presented within 12 months of injury were eligible to participate. Individuals with prior injury or surgery of either knee, greater than a grade 1 concomitant knee ligament injury, or ACL insertion sites less than 14 mm or greater than 18 mm were excluded. Subjects were randomized to undergo SB or DB ACLR with a 10 mm-wide quadriceps tendon autograft harvested with a patellar bone block and were followed for 24 months. The primary outcome measures included the IKDC-SKF and KT-1000 (side to side difference) and pivot shift tests. Other secondary outcomes included measures of sports activity and participation, range of motion (ROM) and re-injury.

RESULTS

Enrollment in the study was suspended due to patellar fractures related to harvest of the patellar bone plug. At that time, 57 subjects had been randomized (29 DB) and two-year follow-up was attained from 51 (89.5%). At 24-month follow-up there were no between-group differences detected for the primary outcomes. Twenty-one (77.8%) DB's and 20 (83.3%) SB's reported returning to pre-injury sports 2 years after surgery (n.s) Three subjects (2 DB's, 5.3% of total) sustained a graft rupture and 5 individuals (4 SB's, 8.8% of total) had a subsequent meniscus injury.

CONCLUSIONS

Due to the early termination of the study, there were no detectable differences in clinical outcome between anatomic SB and DB ACLR when performed with a quadriceps tendon autograft with a bone block in individuals with ACL insertion sites that range from 14 to 18 mm.

LEVEL OF EVIDENCE

Level 2.

Management of multiligament knee injuries

Up to 18% of multiligament knee injuries (MLKI) have an associated vascular injury.All MLKI should be assessed using the ankle brachial pressure index (ABPI) with selective arteriography if ABPI is < 0.9.An ischaemic limb following knee dislocation must be taken to the operating theatre immediately for stabilization and re-vascularization.Partial common peroneal nerve (CPN) injury following MLKI has better recovery than complete palsy.Posterior tibial tendon transfer is offered to patients with complete CPN palsy if there is no recovery at six months.Operative treatment with acute or staged reconstructions provides the best outcome in MLKI.Effective repair can only be performed within three weeks of injury.There is no difference between repair and reconstruction of medial collateral ligament and posteromedial corner.Posterolateral corner reconstruction has a lower failure rate than repair.Early mobilization following MLKI surgery results in fewer range-of-motion deficits. Cite this article: EFORT Open Rev 2020;5:145-155. DOI: 10.1302/2058-5241.5.190012.

Long term results after double and single bundle ACL reconstruction: Is there any difference? A meta - analysis of randomized controlled trials

Objective

The double-bundle (DB) techniques are considered to yield better stability of the knee compared with single-bundle (SB) for anterior cruciate ligament (ACL) reconstruction. However, most studies followed up patients in short to middle-term within 5 years, and the longer-term efficacy of SB and DB ACL reconstruction is still beyond consensus. The purpose of this meta-analysis is to compare the longer-term efficacy between double-bundle (DB) and single-bundle (SB) techniques.

Methods

PubMed, EMBASE, and Cochrane Library databases were searched for relevant articles published up to November, 2017 with an English language restriction. The searches were limited to human subjects and randomized controlled trials (RCTs). In addition, the reference lists of identified articles were checked manually to avoid missing other potentially eligible studies. This process was performed iteratively until no additional articles could be included. The quality of the included studies was assessed using The Cochrane Collaboration's risk of bias tool. All statistical analyses were performed with Review Manager soft-ware.

Results

A total of five RCTs involving 294 patients were included finally. No studies were excluded due to insufficient data or low quality. The pooled results showed no statistically significant difference between SB and double bundle DB reconstructions for Lysholm, IKDC, pivot shift, KT scores, and the development of osteoarthritis at a minimum of 5 years. No significant heterogeneity was found across all outcomes.

Conclusion

The best available evidence demonstrated that SB and DB techniques could yield similar efficacy for ACL reconstruction. And no superiority was founded in DB ACL reconstruction with a minimal 5-year follow-up. Given that, the relatively simple and proven techniques of SB ACL reconstruction may be preferable for orthopedic surgeons.

Level of evidence: Level I, Therapeutic Study.

Comparison of Clinical Results, Second-Look Arthroscopic Findings, and MRI Findings Between the Transportal and Outside-In Techniques for Double-Bundle Anatomic Anterior Cruciate Ligament Reconstruction: A Prospective, Randomized Controlled Trial With a Minimum 2-Year Follow-up

BACKGROUND

Although image analysis has shown that the outside-in (OI) technique is associated with different femoral tunnel geometry than the transportal (TP) technique in anatomic anterior cruciate ligament (ACL) reconstruction, it is not known whether clinical results differ between the 2 techniques.

PURPOSE

To compare clinical results, second-look arthroscopic findings, and magnetic resonance imaging (MRI) findings between the TP and OI techniques in anatomic double-bundle (DB) ACL reconstruction.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

From November 2010 to March 2013, 128 patients were enrolled in this study and were randomly assigned to either the TP group (64 patients) or the OI group (64 patients), and DB ACL reconstructions were performed. At the minimum 2-year follow-up (34.9 ± 10.9 months), 111 patients (86.7%) were evaluated with multiple clinical scores and stability tests (KT-2000 arthrometer, Lachman test, and pivot-shift test). Ninety-three knees were evaluated for graft continuity, graft tension, and synovialization by use of second-look arthroscopy. Seventy-eight knees were evaluated on MRI for graft continuity, femoral graft tunnel healing, and graft signal/noise quotient (SNQ). The primary outcome was KT-2000 arthrometer results. Results were compared between the TP and OI groups.

RESULTS

No significant differences were found between the 2 groups in terms of KT-2000 arthrometer results, which was the primary outcome, and other clinical results, with the exception of the postoperative functional test of International Knee Documentation Committee (IKDC) objective score. The ratio of grade A and B on the postoperative functional test of IKDC objective score was significantly larger for the OI group (51/58) than the TP group (36/53) ( P = .005). The second-look arthroscopic findings were not significantly different between the 2 groups in either bundle ( P > .05). In addition, MRI findings did not differ significantly between the 2 groups ( P > .05).

CONCLUSION

With the exception of the functional test of IKDC objective score, we found that clinical results, second-look arthroscopic findings, and MRI findings did not differ significantly between the OI and TP techniques for anatomic ACL reconstruction, although femoral tunnel geometries differed significantly between the 2 techniques.

Does additional reconstruction of the anterolateral ligament during a primary anterior cruciate ligament reconstruction affect tibial rotational laxity - A case series

Background

The current evidence suggests that rotational stability in not restored in patients with anterior cruciate ligament (ACL) ruptures, despite reconstructive surgery. The graded pivot-shift is a useful clinical test to delineate extent of ligamentous laxity within the knee. Given its lateralised position, we hypothesized that reconstruction of the anterolateral ligament (ALL) would provide restraint to excessive internal rotation, restoring rotational stability.

Methods

10 patients with MRI confirmed diagnosis of an isolated ACL rupture were included. Patients assigned a grade-3 pivot-shift underwent dual-ligament reconstruction for the ACL and ALL (Group 2), whilst patients with an absent pivot-shift, grade-1 or grade-2 underwent single ligament reconstruction for just the ACL (Group 1). Total range of rotation (TRR) was measured using a 3D-kinematic system at 30°,60°and 90° of knee flexion. Data was collected on the pathology-free contralateral normal knee (CNK), ACL-deficient knee (ADK) and the ACL-reconstructed knee (ARK).

Results

A statistically significant pre-operative difference in TRR between the CNK and ADK was noted between Group 1 and 2 (4.04° vs. 1.53°; p < 0.05). Postoperatively, both groups achieved a TRR that was either equivalent, or surpassed values that were observed on the CNKs. The absolute and percentage reduction in TRR at 30° of knee flexion was significantly higher in Group-2 compared to Group-1 (−8.15° vs. −2.96°; p < 0.001) and (28.04% vs. 13.31%; p < 0.001) respectively.

Conclusion

Our findings are based primarily in anaesthetized patients, with kinematic values at time-zero postoperatively. Patients presenting with significant rotational instability following a primary ACL injury and assessed to have a grade-3 pivot-shift may benefit from dual-ligament reconstruction. Further research is required to assess long-term patient-centered clinical outcomes.

•

To prevent excessive rotation in the knee, a structure needs to be present away from the centre axis; at the edge of a plane, resisting rotational motion.

•

The graded pivot-shift is a useful clinical test to help delineate extent of ligamentous laxity within the knee.

•

The higher the grade of the pivot-shift in the ACL deficient knee, the greater the TRR present.

•

The ALL plays a significant role in ACL deficient knees with a grade-3 pivot shift, restoring TRR at time-zero.

•

Further research is required assessing long-term patient-centered clinical outcomes.

In-out versus out-in technique for ACL reconstruction: a prospective clinical and radiological comparison

Background

Several studies have recently shown better restoration of normal knee kinematics and improvement of rotator knee stability after reconstruction with higher femoral tunnel obliquity. The aim of this study is to evaluate tunnel obliquity, length, and posterior wall blowout in single-bundle anterior cruciate ligament (ACL) reconstruction, comparing the transtibial (TT) technique and the out–in (OI) technique.

Materials and methods

Forty consecutive patients operated on for ACL reconstruction with hamstrings were randomly divided into two groups: group A underwent a TT technique, while group B underwent an OI technique. At mean follow-up of 10 months, clinical results and obliquity, length, and posterior wall blowout of femoral tunnels in sagittal and coronal planes using computed tomography (CT) scan were assessed.

Results

In sagittal plane, femoral tunnel obliquity was 38.6 ± 10.2° in group A and 36.6 ± 11.8° in group B (p = 0.63). In coronal plane, femoral tunnel obliquity was 57.8 ± 5.8° in group A and 35.8 ± 8.2° in group B (p = 0.009). Mean tunnel length was 40.3 ± 1.2 mm in group A and 32.9 ± 2.3 mm in group B (p = 0.01). No cases of posterior wall compromise were observed in any patient of either group. Clinical results were not significantly different between the two groups.

Conclusions

The OI technique provides greater obliquity of the femoral tunnel in coronal plane, along with satisfactory length of the tunnel and lack of posterior wall compromise.

Level of evidence

II, prospective study.

Double-bundle anterior cruciate ligament reconstruction is superior to single-bundle reconstruction in terms of revision frequency: a study of 22,460 patients from the Swedish National Knee Ligament Register

PURPOSE

Studies comparing single- and double-bundle anterior cruciate ligament (ACL) reconstructions often include a combined analysis of anatomic and non-anatomic techniques. The purpose of this study was to compare the revision rates between single- and double-bundle ACL reconstructions in the Swedish National Knee Ligament Register with regard to surgical variables as determined by the anatomic ACL reconstruction scoring checklist (AARSC).

METHODS

Patients from the Swedish National Knee Ligament Register who underwent either single- or double-bundle ACL reconstruction with hamstring tendon autograft during the period 2007-2014 were included. The follow-up period started with primary ACL reconstruction, and the outcome measure was set as revision surgery. An online questionnaire based on the items of the AARSC was used to determine the surgical technique implemented in the single-bundle procedures. These were organized into subgroups based on surgical variables, and the revision rates were compared with the double-bundle ACL reconstruction. Hazard ratios (HR) with 95% confidence interval (CI) was calculated and adjusted for confounders by Cox regression.

RESULTS

A total of 22,460 patients were included in the study, of which 21,846 were single-bundle and 614 were double-bundle ACL reconstruction. Double-bundle ACL reconstruction had a revision frequency of 2.0% (n = 12) and single-bundle 3.2% (n = 689). Single-bundle reconstruction had an increased risk of revision surgery compared with double-bundle [adjusted HR 1.98 (95% CI 1.12-3.51), p = 0.019]. The subgroup analysis showed a significantly increased risk of revision surgery in patients undergoing single-bundle with anatomic technique using transportal drilling [adjusted HR 2.51 (95% CI 1.39-4.54), p = 0.002] compared with double-bundle ACL reconstruction. Utilizing a more complete anatomic technique according to the AARSC lowered the hazard rate considerably when transportal drilling was performed but still resulted in significantly increased risk of revision surgery compared with double-bundle ACL reconstruction [adjusted HR 1.87 (95% CI 1.04-3.38), p = 0.037].

CONCLUSIONS

Double-bundle ACL reconstruction is associated with a lower risk of revision surgery than single-bundle ACL reconstruction. Single-bundle procedures performed using transportal femoral drilling technique had significantly higher risk of revision surgery compared with double-bundle. However, a reference reconstruction with transportal drilling defined as a more complete anatomic reconstruction reduces the risk of revision surgery considerably.

LEVEL OF EVIDENCE

III.

Biologic agents for anterior cruciate ligament healing: A systematic review

AIM

To systematically review the currently available literature concerning the application of biologic agents such as platelet-rich plasma (PRP) and stem cells to promote anterior cruciate ligament (ACL) healing.

METHODS

A systematic review of the literature was performed on the use of biologic agents (i.e., PRP or stem cells) to favor ACL healing during reconstruction or repair. The following inclusion criteria for relevant articles were used: Clinical reports of any level of evidence, written in English language, on the use of PRP or stem cells during ACL reconstruction/repair. Exclusion criteria were articles written in other languages, reviews, or studies analyzing other applications of PRP/stem cells in knee surgery not related to promoting ACL healing.

RESULTS

The database search identified 394 records that were screened. A total of 23 studies were included in the final analysis: In one paper stem cells were applied for ACL healing, in one paper there was a concomitant application of PRP and stem cells, whereas in the remaining 21 papers PRP was used. Based on the ACL injury pattern, two papers investigated biologic agents in ACL partial tears whereas 21 papers in ACL reconstruction. Looking at the quality of the available literature, 17 out of 21 studies dealing with ACL reconstruction were randomized controlled trials. Both studies on ACL repair were case series.

CONCLUSION

There is a paucity of clinical trials investigating the role of stem cells in promoting ACL healing both in case of partial and complete tears. The role of PRP is still controversial and the only advantage emerging from the literature is related to a better graft maturation over time, without documenting beneficial effects in terms of clinical outcome, bone-graft integration and prevention of bony tunnel enlargement.

A Systematic Summary of Systematic Reviews on the Topic of the Anterior Cruciate Ligament

BACKGROUND

There has been a substantial increase in the amount of systematic reviews and meta-analyses published on the anterior cruciate ligament (ACL).

PURPOSE

To quantify the number of systematic reviews and meta-analyses published on the ACL in the past decade and to provide an overall summary of this literature.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review of all ACL-related systematic reviews and meta-analyses published between January 2004 and September 2014 was performed using PubMed, MEDLINE, and the Cochrane Database. Narrative reviews and non-English articles were excluded.

RESULTS

A total of 1031 articles were found, of which 240 met the inclusion criteria. Included articles were summarized and divided into 17 topics: anatomy, epidemiology, prevention, associated injuries, diagnosis, operative versus nonoperative management, graft choice, surgical technique, fixation methods, computer-assisted surgery, platelet-rich plasma, rehabilitation, return to play, outcomes assessment, arthritis, complications, and miscellaneous.

CONCLUSION

A summary of systematic reviews on the ACL can supply the surgeon with a single source for the most up-to-date synthesis of the literature.

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.

Placement of Double Tunnels in ACL Reconstruction Using Bony Landmarks Versus Existing Footprint Remnant: A Prospective Clinical Study With 2-Year Follow-up

BACKGROUND

The outcomes of double-bundle anterior cruciate ligament reconstruction (DB-ACLR) are becoming controversial. One of the main reasons for the controversy is the techniques for bone tunnel placement. The common technique to place the bone tunnels is to use bony landmarks, while a new approach uses footprint remnants.

PURPOSE

To investigate if placement of double tunnels using bony landmarks produces the same clinical results as that of using existing footprint remnants.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

A total of 72 male patients were randomly divided into 2 groups of 36 patients each: (A) DB-ACLR tunnel placement using the footprint remnant procedure (EF group) and (B) DB-ACLR tunnel placement using the bony landmark procedure (BL group). All patients were evaluated before and after surgery. Outcomes were measured by KT-2000 arthrometer side-to-side difference, pivot-shift test, and Tegner, Lysholm, and International Knee Documentation Committee (IKDC) scores. Second-look arthroscopic evaluations were performed in 59 cases (28 and 31 cases in the EF and BL groups, respectively).

RESULTS

The mean follow-up time was 36.9±4.8 months. Postoperative 3-dimensional computed tomography scans showed that bone sockets were variable on both femoral and tibial sides in the EF group and almost consistent in the BL group. All of the evaluation indexes were significantly improved postoperatively in both groups. There were no revision cases in the EF group and 2 in the BL group. The EF group showed a faster range of motion (ROM) recovery (at 0° to 120°) than did the BL group. At final follow-up, there was no significant difference between the EF and BL groups in Tegner score (5.88±1.39 vs 5.16±1.76; P=.058) or pivot-shift test (34 vs 32; P=.067). The EF group had a larger proportion of patients with IKDC grade A (normal) (33 vs 24; P<.020), smaller side-to-side difference (0.68±0.38 mm vs 1.23±0.61 mm; P<.001), higher Lysholm score (91.29±4.90 vs 88.71±5.09; P=.032), and better second-look arthroscopic evaluations for graft quality in the anteromedial (P=.034), posterolateral (P=.015), and combined bundles (P=.029) compared with the BL group.

CONCLUSION

Although both techniques provided satisfactory clinical results, DB-ACLR using the existing footprint remnant for tunnel placement showed better functional results with respect to faster ROM recovery, higher subjective outcome scores, and better arthroscopic second-look with no revision cases.

Stability Outcomes following Computer-Assisted ACL Reconstruction

Purpose. The purpose of this study was to determine whether intraoperative prereconstruction stability measurements and/or patient characteristics were associated with final knee stability after computer-assisted ACL reconstruction. Methods. This was a retrospective review of all patients who underwent computer-assisted single-bundle ACL reconstruction by a single surgeon. Prereconstruction intraoperative stability measurements were correlated with patient characteristics and postreconstruction stability measurements. 143 patients were included (87 male and 56 female). Average age was 29.8 years (SD ± 11.8). Results. Females were found to have significantly more pre- and postreconstruction internal rotation than males (P < 0.001 and P = 0.001, resp.). Patients with additional intra-articular injuries demonstrated more prereconstruction anterior instability than patients with isolated ACL tears (P < 0.001). After reconstruction, these patients also had higher residual anterior translation (P = 0.01). Among all patients with ACL reconstructions, the percent of correction of anterior translation was found to be significantly higher than the percent of correction for internal or external rotation (P < 0.001). Conclusion. Anterior translation was corrected the most using a single-bundle ACL reconstruction. Females had higher pre- and postoperative internal rotation. Patients with additional injuries had greater original anterior translation and less operative correction of anterior translation compared to patients with isolated ACL tears.

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.

Preoperative patient and injury factors of successful rehabilitation after anterior cruciate ligament reconstruction with single-bundle techniques

PURPOSE

The aim of this systematic review was to determine which patient determinants and injury factors, before anterior cruciate ligament reconstruction by arthroscopic single-bundle techniques, affect postoperative rehabilitation.

METHODS

A search of PubMed, Embase, and the Cochrane Database of Clinical Trials was performed up to February 2013. After application of our inclusion criteria, a final selection was made based on studies' methodologic score assessed with the Newcastle-Ottawa Scale. Meta-analysis was planned for each prognostic factor when data were considered clinically and statistically homogeneous.

RESULTS

Meta-analysis showed that male patients have better functional outcomes. Qualitative synthesis from 18 high-quality studies showed that patients operated on before 30 years of age reach higher activity levels. Patients with high baseline body mass index have lower activity levels after surgery. Smoking results in more symptoms and lower activity levels and subjective scores. Reconstruction before 3 months results in higher activity levels. Preoperatively, a less than 20% quadriceps strength difference, 50° of tibial external rotation or less, absence of flexion deficits, low knee influence on the patient's activity level, and less anterior knee pain result in higher functional scores. Preoperative anterior laxity difference does not predict functional scores. The prognostic value of preoperative activity and competition level for postoperative functional outcome is controversial. Patients with concomitant meniscal injuries have worse functional outcomes. The prognostic value of concomitant chondral pathology for postoperative functional outcome is controversial. Collateral ligament injury could predict functional scores or activity level.

CONCLUSIONS

Male gender, patient age younger than 30 years, reconstruction before 3 months, and high baseline activity level contribute to better functional outcomes. Smoking, high body mass index, quadriceps strength, and range-of-motion deficits affect rehabilitation negatively. Preoperative anterior laxity does not influence rehabilitation. The role of preoperative prognostic injury factors remains unclear because of limited evidence.

LEVEL OF EVIDENCE

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

A prospective randomized study comparing double- and single-bundle techniques for anterior cruciate ligament reconstruction

BACKGROUND

The aim of the study was to compare the results after arthroscopic anterior cruciate ligament (ACL) reconstruction using either the double-bundle or single-bundle technique with hamstring tendon autografts in an unselected group of patients.

HYPOTHESIS

Double-bundle ACL reconstruction will render a better outcome on the pivot-shift test.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A randomized series of 103 patients (33 women, 70 men; median age, 27 years; range, 18-52 years) with a unilateral ACL rupture underwent anatomic ACL reconstruction. The double-bundle technique was used in 53 patients, and the single-bundle technique was used in 50 patients. The ACL footprint was visualized, and the femoral tunnel was drilled through the anteromedial portal; interference screw fixation was used at both ends. The patients were examined preoperatively and at a median of 26 months (range, 22-42 months) after the reconstruction by a blinded observer. The primary variable was the pivot-shift test.

RESULTS

At 2-year follow-up, 98 patients (93%) were examined. Clinical assessments at follow-up revealed no significant differences between the double-bundle and single-bundle groups in terms of the pivot-shift test, KT-1000 arthrometer laxity measurements, manual Lachman test, range of motion, Lysholm knee scoring scale, Tegner activity scale, Knee Injury and Osteoarthritis and Outcome Score (KOOS), 1-legged hop test, and square hop test. A significant improvement was seen in both groups compared with the preoperative values in terms of most clinical assessments.

CONCLUSION

In this prospective randomized study, the primary variable, the pivot-shift test, and other subjective and objective outcome variables revealed no significant differences between the double-bundle and single-bundle techniques at 2 years after ACL reconstruction in an unselected group of patients.

Single-bundle versus double-bundle anterior cruciate ligament reconstruction: an up-to-date meta-analysis

PURPOSE

The aim of this meta-analysis was to compare the results of arthroscopic single-bundle and double-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

We systematically searched electronic databases to identify randomised controlled trials (RCTs) in which arthroscopic single-bundle was compared with double-bundle for ACL reconstruction. The search strategy followed the requirements of the Cochrane Library Handbook. The outcomes of these studies were analysed in terms of graft failures, Lysholm score, negative pivot-shift test, KT1000 arthrometer measurements, knee extensor and flexor peak torques, knee extension and flexion deficit, and subjective and objective International Knee Documentation Committee (IKDC) final score. Methodological quality was assessed and data were extracted independently. Standard mean difference (SMD) or odds ratio (OR) with 95 % confidence interval (CI) was calculated by a fixed effects or random effects model. Heterogeneity across the studies was assessed with the I-square and chi-square statistic. Forest plots were also generated.

RESULTS

We identified 17 RCTs comprising 1,381 patients who were treated by arthroscopic single-bundle versus double-bundle ACL reconstruction. The results of meta-analysis of these studies showed that arthroscopic double-bundle reconstruction was associated with a lower risk of graft failures (P=0.002) and a lower rate of positive pivot-shift test (P<0.0001). Compared with single-bundle reconstruction, double-bundle reconstruction had a lower KT1000 arthrometer measurement (P<0.00001), a lower knee extension deficit (P=0.006) and a higher subjective IKDC score (P=0.03). There was no statistically significant difference between single-bundle and double-bundle reconstruction in Lysholm score (P=0.91), knee extensor peak torques (P=0.97), knee flexor peak torques (P=0.96), knee flexion deficit (P=0.30) and objective IKDC score (P=0.18).

CONCLUSIONS

Considering the more favourable outcomes of graft failures, knee joint stability and knee joint function in double-bundle reconstruction, we concluded that arthroscopic double-bundle reconstruction should be considered as the primary treatment in ACL reconstruction.