Transtibial versus independent drilling techniques for anterior cruciate ligament reconstruction: a systematic review, meta-analysis, and meta-regression

Analysis of Changing Practice Trends in Anterior Cruciate Ligament Reconstruction: A Multicenter, Single-Institution Database Analysis

PURPOSE

To identify trends in anterior cruciate ligament reconstruction (ACLR), including graft choice, femoral tunnel drilling techniques, and augmentation techniques, and to assess how various surgeon factors impact these trends.

METHODS

A retrospective review of primary ACLRs performed between 2014 and 2022 was completed using a multicenter institutional database. Patient demographic characteristics, graft type, femoral drilling technique, use of extra-articular tenodesis, and use of suture augmentation were recorded from the medical record. Surgeon fellowship training (sports trained vs non-sports trained), experience (high [minimum of 15 years in practice] vs low), and volume (high [minimum of 15 ACLRs/year] vs low) were used to stratify technique utilization. The z test for proportions was used to compare categorical variables. Pearson correlation analyses identified trends and assessed statistical significance, defined as P < .05.

RESULTS

Our cohort consisted of 2,032 ACLRs performed in 2,006 patients. The average patient age was 28.3 ± 11.6 years, with more procedures performed in male patients (67.3%). The average length of surgeon experience was 19.7 ± 11.4 years, with an average annual procedural volume of 4.0 ± 5.4 ACLRs. Most surgeons were sports trained (n = 55, 64.7%), high experience (n = 44, 57.1%), and low volume (n = 80, 94.1%). There was an increasing annual proportion of ACLRs performed by sports-trained surgeons (R = 0.748, P = .020) and low-experience surgeons (R = 0.940, P < .001). Autograft reconstructions were most often performed by sports-trained (71.2%), low-experience (66.1%), and high-volume (76.9%) surgeons. There was an increasing proportion of autograft ACLRs that used quadriceps tendon among sports-trained (R = 0.739, P = .023), high-experience (R = 0.768, P = .016), and low-volume (R = 0.785, P = .012) surgeons. Independent drilling techniques were used in an increasing proportion of ACLRs performed by non-sports-trained (R = 0.860, P = .003) and high-volume (R = 0.864, P = .003) surgeons. Augmentation of ACLR with concomitant suture augmentation (n = 24, 1.2%) or extra-articular tenodesis (n = 6, 0.3%) was rarely performed.

CONCLUSIONS

In our multicenter institution, the quadriceps tendon autograft has been increasingly used in ACLR by sports-trained, low-volume, and high-experience surgeons. Independent drilling techniques have been increasingly used by non-sports-trained and high-volume surgeons.

CLINICAL RELEVANCE

Surgeons must stay current with the literature that affects their procedures to ensure that evidence-based medicine is being practiced.

The method of femoral tunnel drilling in anterior cruciate ligament reconstruction does not influence the return to sport rate

Background

Limited evidence is available comparing the modified transtibial (MTT) and transportal (TP) techniques in anterior cruciate ligament (ACL) reconstruction and their impact on returning to sports participation. The objective was to analyze the outcomes after arthroscopic reconstruction of the ACL in recreational athletes with a 2-year postoperative follow-up, comparing the MTT and TP techniques, based on the method used to drill the femoral tunnel.

Hypotesis

The rate of return to sport would be comparable regardless of the surgical technique used.

Material and methods

A retrospective study was conducted with 66 patients who underwent arthroscopic monofascicular ACL reconstruction between September 2016 and March 2020. Patients aged between 16 and 50 years old, recreational athletes at Tegner levels 6 and 7, with a 2-year follow-up were included. Groups were established for comparative analysis (MTT vs TP) based on the method for drilling the femoral tunnel. The main outcome variable was the return to sport at the same level. Secondary variables included patient satisfaction evaluated with a visual analogue scale (VAS) and knee function according to the Lysholm scale.

Results

At 2 years of postoperative follow-up, the return to sport rate was 30.3 % in the MTT group and 33.3 % in the TP group (p = 0.791). There were no significant differences between both groups in patient satisfaction (p = 0.664) and knee function (p = 0.113).

Conclusion

Drilling the femoral tunnel with the MTT and TP techniques did not influence the rate of return to sport, patient satisfaction, and knee function in recreational athletes with 2 years of postoperative follow-up.

Level of evidence

III.

Evaluating femoral graft placement using three-dimensional magnetic resonance imaging in the reconstruction of the anterior cruciate ligament via independent or transtibial drilling techniques: a retrospective cohort study

PURPOSE

Anterior cruciate ligament (ACL) reconstruction is a common surgical procedure, yet failure still largely occurs due to nonanatomically positioned grafts. The purpose of this study was to retrospectively evaluate patients with torn ACLs before and after reconstruction via 3D MRI and thereby assess the accuracy of graft position on the femoral condyle.

METHODS

Forty-one patients with unilateral ACL tears were recruited. Each patient underwent 3D MRI of both knees before and after surgery. The location of the reconstructed femoral footprint relative to the patient's native footprint was compared.

RESULTS

Native ACL anatomical location of the native ACL had a significant impact on graft position. Native ACLs that were previously more anterior yielded grafts that were more posterior (3.70 ± 1.22 mm, P = 0.00018), and native ACL that were previously more proximal yielded grafts that were more distal (3.25 ± 1.09 mm, P = 0.0042). Surgeons using an independent drilling method positioned 76.2% posteriorly relative to the native location, with a mean 0.1 ± 2.8 mm proximal (P = 0.8362) and 1.8 ± 3.0 mm posterior (P = 0.0165). Surgeons using a transtibial method positioned 75% proximal relative to the native location, with a mean 2.2 ± 3.0 mm proximal (P = 0.0042) and 0.2 ± 2.6 mm posterior (P = 0.8007). These two techniques showed a significant difference in magnitude in the distal-proximal axis (P = 0.0332).

CONCLUSION

The femoral footprint position differed between the native and reconstructed ACLs, suggesting that ACL reconstructions are not accurate. Rather, they are converging to a normative reference point that is neither anatomical nor isometric.

Study on the use of 3D printed guides in the individualized reconstruction of the anterior cruciate ligament

OBJECTIVE

Evaluation of the accuracy and effectiveness of 3D printed guides to assist femoral tunnel preparation in individualised reconstruction of the anterior cruciate ligament.

METHODS

Sixty patients who attended the Affiliated Hospital of Binzhou Medical College for autologous hamstring single bundle reconstruction of the anterior cruciate ligament from October 2018 to October 2020 were selected and randomly divided into two groups, including 31 cases in the 3D printing group (14 males and 17 females, mean age 41.94 ± 10.15 years) and 29 cases in the control group (13 males and 16 females, mean age 37.76 ± 10.34 years). Patients in both groups were assessed for intraoperative femoral tunnel accuracy, the number of intraoperative positioning and the time taken to prepare the femoral tunnel, the length of the anteromedial approach incision, the pre-planned bone tunnel length and intraoperative bone tunnel length in the 3D printed group, IKDC score and Lysholm score preoperatively and at 3, 6 and 12 months postoperatively, the Lachman、pivot-shift test preoperatively and at 6 months postoperatively, gait analysis to assess internal and external rotation in flexion of the knee at 12 months postoperatively and postoperative complications in both groups.

RESULTS

There was no statistical difference in functional knee scores and anteromedial approach incision length between the 3D printed and control groups (p > 0.05), while there was a statistical difference in the accuracy of tunnel positioning, the time taken to prepare the femoral bone tunnel and the degree of external rotation of the knee in flexion between the two groups (p < 0.05). There was no statistical difference between the preoperative planning of the bone tunnel length and the intraoperative bone tunnel length (p > 0.05).

COMPLICATIONS

One case in the 3D printing group developed intermuscular vein thrombosis in the affected lower limb after surgery, which disappeared after treatment, while three cases in the control group developed intermuscular vein thrombosis in the affected lower limb. No complications such as bone tunnel rupture, deep vein thrombosis in the lower limb and infection occurred in either group.

CONCLUSION

3D printed guides assisted with individualized ACL reconstruction may improve the accuracy of femoral tunnel positioning, which is safe and effective, while reducing the operative time and the number of intraoperative positioning, without increasing the length of incision, and may obtain higher functional scores and rotational stability of the knee joint, which is in line with the concept of individualized ACL reconstruction.

Revision Rates After Primary Allograft ACL Reconstruction by Allograft Tissue Type in Older Patients

Background

While there is extensive literature on the use of allograft versus autograft in anterior cruciate ligament (ACL) reconstruction, there is limited clinical evidence to guide the surgeon in choice of allograft tissue type.

Purpose

To assess the revision rate after primary ACL reconstruction with allograft and to compare revision rates based on allograft tissue type and characteristics.

Study Design

Cohort study; Level of evidence, 3.

Methods

Patients who underwent primary allograft ACL reconstructions at a single academic institution between 2015 and 2019 and who had minimum 2-year follow-up were included. Exclusion criteria were missing surgical or allograft tissue type data. Demographics, operative details, and subsequent surgical procedures were collected. Allograft details included graft tissue type (Achilles, bone-patellar tendon-bone [BTB], tibialis anterior or posterior, semitendinosus, unspecified soft tissue), allograft category (all-soft tissue vs bone block), donor age, irradiation duration and intensity, and chemical cleansing process. Revision rates were calculated and compared by allograft characteristics.

Results

Included were 418 patients (age, 39 ± 12 years; body mass index, 30 ± 9 kg/m2). The revision rate was 3% (11/418) at a mean follow-up of 4.9 ± 1.4 years. There were no differences in revision rate according to allograft tissue type across Achilles tendon (3%; 3/95), BTB (5%; 3/58), tibialis anterior or posterior (3%; 5/162), semitendinosus (0%; 0/46), or unspecified soft tissue (0%; 0/57) (P = .35). There was no difference in revision rate between all-soft tissue versus bone block allograft (6/283 [2%] vs 5/135 [4%], respectively; P = .34). Of the 51% of grafts with irradiation data, all grafts were irradiated, with levels varying from 1.5 to 2.7 Mrad and 82% of grafts having levels of <2.0 Mrad. There was no difference in revision rate between the low-dose and medium-to high-dose irradiation cohorts (4% vs 6%, respectively; P = .64).

Conclusion

Similarly low (0%-6%) revision rates after primary ACL reconstruction were seen regardless of allograft tissue type, bone block versus all-soft tissue allograft, and sterilization technique in 418 patients with mean age of 39 years. Surgeons may consider appropriately processed allograft tissue with or without bone block when indicating ACL reconstruction in older patients.

Knee Extensor Mechanism Complications After Autograft Harvest in ACL Reconstruction: A Systematic Review and Meta-analysis

Background

Existing systematic reviews have sought to characterize the relative donor-site morbidity of bone-patellar tendon-bone (BTB) and quadriceps tendon (QT) grafts after anterior cruciate ligament reconstruction (ACLR). However, no studies have reported the pooled proportions of patellar fractures and donor tendon ruptures across the body of literature.

Purpose

To estimate the proportion of patellar fractures, patellar tendon ruptures, and QT ruptures associated with BTB or QT autograft harvest during ACLR using published data.

Study Design

Systematic review; Level of evidence, 4.

Methods

A meta-analysis was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using 3 online databases (PubMed, Scopus, and Web of Science). A total of 800 manuscripts were included in the initial research of peer-reviewed articles in English that reported extensor mechanism complications associated with graft harvest in patients after ACLR. Pooled proportions of patellar fractures, patellar tendon ruptures, and QT ruptures were calculated for each graft type (BTB, QT) using a random-effects model for meta-analysis.

Results

A total of 28 studies were analyzed. The pooled proportion of patellar fractures was 0.57% (95% CI, 0.34%-0.91%) for the BTB harvest and 2.03% (95% CI, 0.78%-3.89%) for the QT harvest. The proportion of patellar tendon ruptures was 0.22% (95% CI, 0.14%-0.33%) after the BTB harvest, and the proportion of QT ruptures was 0.52% (95% CI, 0.06%-1.91%) after the QT harvest. The majority of included studies (16/28 [57.1%]) had an evidence level of 4.

Conclusion

Based on the current literature, the proportion of extensor mechanism complications after ACLR using either a BTB or a QT autograft is low, indicating that the extensor mechanism harvest remains a safe option. A higher proportion of patellar fractures was noted for QT grafts and a higher proportion of donor tendon ruptures was noted for QT grafts compared with BTB grafts.

Anteromedial Portal Technique, but Not Outside-in Technique, Is Superior to Standard Transtibial Technique in Knee Stability and Functional Recovery After Anterior Cruciate Ligament Reconstruction: A Network Meta-analysis

PURPOSE

To compare the postoperative outcomes of 4 different femoral drilling techniques in anterior cruciate ligament reconstruction.

METHODS

Three databases were searched for randomized controlled trials comparing any 2 or more of the following femoral drilling techniques in anterior cruciate ligament reconstruction: standard transtibial (sTT), anteromedial portal (AMP), outside-in (OI), or modified transtibial (mTT) technique. A Bayesian network meta-analysis was performed to assess postoperative stability and functional recovery in terms of the side-to-side difference (measured by arthrometry), Lachman test, pivot-shift test, International Knee Documentation Committee subjective and objective scores, Lysholm score, and Tegner score. The Fisher exact probability test and χ2 test were used to compare the incidences of infection and graft rupture, respectively.

RESULTS

We included 20 randomized controlled trials involving 1,515 patients. The AMP technique showed a lower side-to-side difference (standardized mean difference, -0.33; 95% credible interval [CrI], -0.53 to -0.12), higher negative rate on the pivot-shift test (odds ratio, 2.19; 95% CrI, 1.38 to 3.44), and higher International Knee Documentation Committee objective score (odds ratio, 3.13; 95% CrI, 1.42 to 7.82) than the sTT technique. However, knee stability and functional outcomes did not differ significantly between the OI and sTT techniques. Safety outcomes of the mTT technique were unavailable. The incidence of graft rupture was 5.20% for the OI technique, 2.27% for the AMP technique, and 1.51% for the sTT technique. The OI technique had a significantly higher incidence of graft rupture than the sTT technique (χ2 = 4.421, P = .035). No significant difference in the incidence of infection was found between the sTT, AMP, and OI techniques (P = .281).

CONCLUSIONS

The AMP technique, but not the OI technique, was superior to the sTT technique in knee stability and functional recovery. The OI technique had a higher incidence of graft rupture than the sTT technique. There was no significant difference between the AMP and OI techniques or between the mTT technique and any other femoral drilling technique.

LEVEL OF EVIDENCE

Level II, meta-analysis of Level I and II studies.

Editorial Commentary: Anteromedial Portal Drilling of the ACL Femoral Socket Avoids Transtibial Constraint Results in Anatomic Reconstruction and Superior Outcomes

Femoral and tibial tunnel locations for ACL grafts should be predicated on anatomy. Regarding femoral ACL socket or tunnel creation, multiple techniques have been debated. Network meta-analysis shows that the anteromedial portal (AMP) technique results in better anteroposterior and rotational stability than does the "standard" constrained, transtibial technique based on side-to-side differences in laxity and pivot-shift tests, as well as IKDC objective scores. The AMP provides a direct shot at the anatomic ACL origin on the femur. It avoids the osseous constraint of the reamer that hampers transtibial approaches. It avoids the extra incision required by the outside-in technique and the accompanying graft obliquity. Despite the need for knee hyperflexion and the potential for shorter femoral sockets, the AMP technique should be easily reproducible for an accomplished ACL surgeon to reproduce the patient's anatomy.

Transtibial Versus Anteromedial Portal Technique for Femoral Tunnel Drilling in Primary Single-Bundle Anterior Cruciate Ligament Reconstruction: A Meta-analysis of Level 1 and 2 Evidence of Clinical, Revision, and Radiological Outcomes

BACKGROUND

Although numerous clinical studies have compared transtibial (TT) and anteromedial portal (AMP) drilling of femoral tunnels during anterior cruciate ligament reconstruction (ACLR), there is no high-quality, evidence-based consensus regarding which technique affords the best outcome.

HYPOTHESIS

There would be no difference between the TT and AMP techniques in terms of knee stability, patient-reported outcomes, incidence of revision, and radiological results.

STUDY DESIGN

Meta-analysis; Level of evidence, 2.

METHODS

The PubMed and EMBASE databases were searched from inception to February 1, 2021. Level 1 and 2 clinical trials that compared TT and AM techniques were included. Data were meta-analyzed for the outcome measures of knee stability, patient-reported functional outcomes, incidence of revision, and radiological results. Dichotomous variables were presented as odds ratios (ORs), and continuous variables were presented as mean differences (MDs) and standard mean differences (SMDs).

RESULTS

The meta-analysis included 18 clinical studies, level of evidence 1 or 2, that involved 53,888 patients. Pooled data showed that the AMP group had a lower side-to-side difference (SMD, 0.22; 95% CI, 0.06 to 0.39; P = .009), a lower incidence of pivot-shift phenomenon (OR, 3.69; 95% CI, 1.26 to 10.79; P = .02), and a higher postoperative Lysholm score (SMD, -0.26; 95% CI, -0.44 to -0.08; P = .005) than the TT group. However, no statistically significant differences were seen in other outcomes, including subjective International Knee Documentation Committee scores (SMD, -0.11; 95% CI, -0.30 to 0.09; P = .30) or grades (OR, 0.93; 95% CI, 0.35 to 2.49; P = .89), postoperative activity level (MD, -0.14; 95% CI, -0.42 to 0.15; P = .35), and incidence of revision ACLR (OR, 1.04; 95% CI, 0.93 to 1.16; P = .45). The TT technique was more likely to create longer (SMD, 1.05; 95% CI, 0.05 to 2.06; P = .04) and more oblique (SMD, 0.81; 95% CI, 0.51 to 1.11; P < .001) femoral tunnels than the AMP technique, and a higher height ratio of the aperture position was detected with the TT technique (SMD, -3.51; 95% CI, -5.54 to -1.49; P < .001).

CONCLUSION

The AMP technique for ACLR may be more likely to produce better knee stability and improved clinical outcomes than the TT technique, but no difference was found in the incidence of revision between the 2 groups.

Comparative analysis of the results of the anterior cruciate ligament reconstruction using an autograft preparation by known and new methods

Background. To date, the problem of choosing the optimal graft for anterior cruciate ligament (ACL) reconstruction and the methods for its formation is one of the main trends in the surgical treatment of patients with anterior knee joint instability.The aim. To compare the results of the anterior cruciate ligament reconstruction using the known method and the new proposed method for autograft formation.Materials and methods. The results of treatment of ACL injury in 44 patients were assessed. In the main group (19 patients), an original technique of ACL reconstruction from 1/2 of the width of m. peroneus longus tendon was used. In the control group (25 patients), ACL reconstruction was performed using a graft from the m. semitendinosus tendon prepared by the Lubowitz method.Results. The mean difference in the circumference of the distal third of the hip in the main group was 1.57 ± 1.162 cm and was statistically significantly better than in the control group, where the mean difference in the hip circumference was 4.74 ± 1.7207 cm.The range of motion of the knee joint in the main group 3 months after the surgery was 128.42 ± 9.287°, and in the control group mean flection was 109.6 ± 9.120°.The functional results in the main group were assessed by the Lisholm scale and were statistically significantly better than the results in the control group. The functional results by the AOFAS (American Orthopedic Foot & Ankle Society) scale in the main group were 100 points before the surgery and at all terms after the surgery: this indicates that the use of 1/2 of the width of m. peroneus longus tendon does not cause the its functional impairement.Conclusion. Anterior cruciate ligament plasty with use of 1/2 of the width of m. peroneus longus tendon prepared by the proposed method showed statistically significantly better results compared to the preparation of autograft from semitendinous muscle tendon using known method.

Anterior Cruciate Ligament Patellar Tendon Autograft Fixation at 0° Versus 30° Results in Improved Activity Scores and a Greater Proportion of Patients Achieving the Minimal Clinical Important Difference For Knee Injury and Osteoarthritis Outcome Score Pain: A Randomized Controlled Trial

PURPOSE

The aim of the current study was to determine the effect of the knee flexion angle (KFA) during tibial anterior cruciate ligament (ACL) graft fixation on patient-reported outcomes, graft stability, extension loss, and reoperation after anatomic single-bundle ACL reconstruction.

METHODS

All 169 included patients (mean age 28.5 years, 65% male) were treated with anatomic single-bundle ACL reconstruction using patellar tendon autograft and were randomized to tibial fixation of the ACL graft at either 0° (n = 85) or 30° (n = 84). The primary outcome was the Knee Injury and Osteoarthritis Outcome Score (KOOS) 2 years after surgery. Secondary outcomes were the Marx Activity Scale (MAS), the rate of reoperation, and physical examination findings at 1 year, including KT-1000 and side-to-side differences in knee extension.

RESULTS

The follow-up rate was 82% (n = 139) for the primary outcome. Graft failure rate at 2 years was 1% (n = 2, 1 per group). ACL tibial graft fixation at 0° or 30° did not have a significant effect on KOOS scores at 2 years after ACLR. Patients whose graft was fixed at a knee flexion angle of 0° had greater scores on the MAS (mean 9.6 95% confidence interval [CI] 8.5 to 10.6, versus 8.0, 95% CI 6.9 to 9.1; P = .04), and a greater proportion achieved the minimal clinical important difference (MCID) for the KOOS pain subdomain (94% versus 81%; P = .04). There was no significant difference in knee extension loss, KT-1000 measurements, or reoperation between the 2 groups.

CONCLUSION

In the setting of anatomic single-bundle ACLR using patellar tendon autograft and anteromedial portal femoral drilling, there was no difference in KOOS scores between patients fixed at 0° and 30°. Patient fixed in full extension did demonstrate higher activity scores at 2 years after surgery and a greater likelihood of achieving the MCID for KOOS pain.

LEVEL OF EVIDENCE

II, prospective randomized trial.

Similar outcomes and satisfaction after transtibial versus transportal femoral drilling for anterior cruciate ligament reconstruction in young adult recreational athletes

PURPOSE

Controversy continues regarding whether the transtibial (TT) and transportal (TP) methods for anterior cruciate ligament (ACL) reconstruction provide similar or different outcomes, and the evidence on patient satisfaction is very limited. The objective of this study was to compare functional outcomes and patient satisfaction in young adult recreational athletes who underwent arthroscopic hamstring ACL reconstruction using either the TT or the TP femoral tunnel drilling method.

METHODS

A nonrandomized prospective study was designed to compare the outcomes of arthroscopic hamstring ACL reconstruction using TT or TP method. Functional outcome was assessed with the Lyshom score, and patient satisfaction with a 5-point Likert scale. Knee stability was measured with the KT-1000 arthrometer.

RESULTS

42 patients in the TT group and 41 in TP group, with age ranged 18-40 years, were compared with a mean follow-up of 42 (range 24-60) months. There were no significant differences between groups in the Lysholm score (n.s.), sport return rate (n.s.) or patient satisfaction with the surgery (n.s.). Satisfaction was only significantly associated with the Lysholm score (OR 1.3; IC 95% 1.06-1.6; p = 0.012), but not with the return to sports (n.s.) or knee anterior laxity (n.s.).

CONCLUSION

This study showed no statistical differences between the TT and the TP method in functional outcomes or patient satisfaction in young adult recreational athletes. In those patients, satisfaction with the surgery was not influenced by the return to sport activities. This study can guide surgeons in the decision-making for ACL reconstruction in recreational athletes.

LEVEL OF EVIDENCE

Level II.

Transtibial versus independent femoral tunnel drilling techniques for anterior cruciate ligament reconstruction: evaluation of femoral aperture positioning

Background

Femoral tunnel can be drilled through tibial tunnel (TT), or independent of it (TI) by out-in (OI) technique or by anteromedial (AM) technique. No consensus has been reached on which technique achieves more proper femoral aperture position because there have been evolving concepts in the ideal place for femoral aperture placement. This meta-analysis was performed to analyze the current literature comparing femoral aperture placement by TI versus TT techniques in ACL reconstruction.

Methods

We performed a comprehensive systematic review and meta-analysis of English-language literature in PubMed, Cochrane, and Web of Science databases for articles comparing femoral aperture placement by TI versus TT techniques with aperture position assessed by direct measurement or by postoperative imaging, PXR and/or CT and/or MRI.

Results

We included 55 articles with study population of 2401 knees of whom 1252 underwent TI and 1149 underwent TT techniques. The relevant baseline characteristics, whenever compared, were comparable between both groups. There was nonsignificant difference between TI and TT techniques in the distance from aperture center to footprint center and both techniques were unable to accurately recreate the anatomic footprint position. TI technique significantly placed aperture at more posterior position than TT technique. TI technique significantly lowered position of placed aperture perpendicular to Blumensaat’s line (BL) than TT technique, and modifications to TT technique had significant effect on this intervention effect. Regarding sagittal plane aperture placement along both AP anatomical axis and BL, there was nonsignificant difference between both techniques.

Conclusion

Modifications to TT technique could overcome limitations in aperture placement perpendicular to BL. The more anterior placement of femoral aperture by TT technique might be considered, to some extent, a proper position according to recent concept of functional anatomical ACL reconstruction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03040-5.

Minimizing the risk of graft failure after anterior cruciate ligament reconstruction in athletes. A narrative review of the current evidence

Anterior cruciate ligament (ACL) tear is one of the most common sport-related injuries and the request for ACL reconstructions is increasing nowadays. Unfortunately, ACL graft failures are reported in up to 34.2% in athletes, representing a traumatic and career-threatening event. It can be convenient to understand the various risk factors for ACL failure, in order to properly inform the patients about the expected outcomes and to minimize the chance of poor results. In literature, a multitude of studies have been performed on the failure risks after ACL reconstruction, but the huge amount of data may generate much confusion.The aim of this review is to resume the data collected from literature on the risk of graft failure after ACL reconstruction in athletes, focusing on the following three key points: individuate the predisposing factors to ACL reconstruction failure, analyze surgical aspects which may have significant impact on outcomes, highlight the current criteria regarding safe return to sport after ACL reconstruction.

Freehand Anatomic Transtibial Single-Bundle Anterior Cruciate Ligament Reconstruction

Creation of the femoral tunnel for single-bundle anterior cruciate ligament (ACL) reconstruction has a high rate of nonanatomic placement with the transtibial (TT) technique but yields better restoration with the anteromedial portal technique and close restoration of the anatomic femoral footprint with the outside-in technique. Modifications of the traditional (TT) technique have been described to restore the native femoral ACL footprint and to simulate double-bundle reconstruction. Modified TT techniques try to capture the anatomic femoral footprint through an anatomic tibial tunnel. In the technique described in this article, the anatomic femoral footprint is drilled first by the use of a 2.5-mm Kirschner wire through the parapatellar anteromedial portal, making an angle 30° to the sagittal plane and 20° to the horizontal plane. The wire is drilled while the knee is hyperflexed and then withdrawn from outside until its distal end reaches the intercondylar notch. The wire is then advanced in an antegrade manner while the knee is flexed 90° until it reaches the center of the marked tibial footprint. The angle of knee flexion may be slightly increased or decreased around 90° with or without slight internal rotation to capture the anatomic tibial footprint. The procedure is completed as a TT single-bundle ACL reconstruction.

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.

Clinical Outcomes of Anterolateral Ligament Reconstruction or Lateral Extra-articular Tenodesis Combined With Primary ACL Reconstruction: A Systematic Review With Meta-analysis

BACKGROUND

Residual rotational instability after isolated anterior cruciate ligament reconstruction (ACLR) has been a challenge for many years. Anterolateral extra-articular procedures (AEAPs), including anterolateral ligament reconstruction (ALLR) or lateral extra-articular tenodesis (LET), are performed as a surgical option for additional rotational stability, but clear evidence for their usefulness is lacking.

PURPOSE

To conduct a systematic review and meta-analysis of the literature regarding the efficacy of AEAP in primary ACLR.

STUDY DESIGN

Systematic review; Level of evidence, 3.

METHODS

A literature search, data extraction, and quality assessment were conducted by 2 independent reviewers. MEDLINE, EMBASE, and the Cochrane Library were searched in April 2020, following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A total of 3444 studies were screened, and 20 studies (11 randomized controlled trials and 9 nonrandomized studies) were evaluated. Functional outcomes, stability, and complications were compared between patients who underwent primary ACLR with AEAP and those who underwent isolated primary ACLR. For subgroup analysis, outcomes were compared according to AEAP technique (ALLR vs LET) and time from injury to surgery (≤12 vs >12 months). The methodological quality of the included studies was assessed using the Cochrane risk-of-bias tool, Jadad scale, and Newcastle-Ottawa Scale.

RESULTS

Compared with isolated ACLR, combined ACLR with AEAP led to improved pivot-shift grades and graft failure rates, regardless of the AEAP technique or of time from injury to surgery. A limited, marginal improvement in subjective function score was observed in patients who underwent AEAP combined with ACLR. In contrast to ALLR, patients who underwent LET combined with ACLR had an increased risk of knee stiffness and adverse events.

CONCLUSION

Our review suggests that when there is a need to improve rotational stability and subjective function, AEAP combined with primary ACLR can be considered regardless of time from injury. ALLR appeared to be a better option for improving rotational stability compared with LET.

The Statistical Fragility of Hamstring Versus Patellar Tendon Autografts for Anterior Cruciate Ligament Reconstruction: A Systematic Review of Comparative Studies

BACKGROUND

Evidence-based medicine utilizes data to inform clinical decision making, despite the ability of a small number of outcome reversals to change statistical significance. P values are common measurements of statistical significance that possess inherent flaws. The inclusion of the fragility index (FI) and fragility quotient (FQ) may provide a clearer conveyance of statistical strength.

PURPOSE/HYPOTHESIS

The purpose was to examine the statistical stability of studies comparing hamstring tendon and bone-patellar tendon-bone autografts in primary single-bundle anterior cruciate ligament reconstruction with independent tunnel drilling. We hypothesized that the findings of these studies are vulnerable to a small number of outcome event reversals, often fewer than the number of patients lost to follow-up.

STUDY DESIGN

Systematic review.

METHODS

Comparative studies and randomized controlled trials (RCTs) published in 10 leading orthopaedic journals between 2000 and 2020 were analyzed. Statistical significance was defined as a P value ≤.05. FI for each outcome was determined by the number of event reversals necessary to alter significance. FQ was calculated by dividing the FI by the respective sample size.

RESULTS

Of the 1803 studies screened, 643 met initial search criteria, with 18 comparative studies ultimately included for analysis, 8 of which were RCTs. A total of 114 outcomes were examined. Overall, the mean (interquartile range) FI and FQ were 3.77 (2-4) and 0.040 (0.016-0.055), respectively. The FI was less than the number of patients lost to follow-up for 76.3% of outcomes.

CONCLUSION

Studies examining graft choice for anterior cruciate ligament reconstruction 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 <4 outcome events in a treatment group can alter the statistical significance of a given result; this is commonly fewer 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.

Independent Versus Transtibial Drilling in Anterior Cruciate Ligament Reconstruction: A Meta-analysis With Meta-regression

Background:

Anterior cruciate ligament (ACL) reconstruction can be performed with different techniques for independent and transtibial (TT) drilling of femoral tunnels, but there is still no consensus on which approach leads to the best outcome.

Purpose:

To assess whether the independent or TT drilling approach for ACL reconstruction leads to the best functional outcomes.

Study Design:

Systematic review; Level of evidence, 2.

Methods:

A systematic literature search was conducted on July 1, 2020, using the PubMed, Web of Science, Cochrane Library, and Scopus databases. The influence of different femoral drilling techniques was analyzed through a meta-analysis in terms of patient-reported outcome measure scores, risk of complications, range of motion limitations, graft failure, and differential laxity. Subanalyses were performed to compare the different independent drilling techniques considered. Linear metaregression was performed to evaluate if the year of study publication influenced the results. The risk of bias and quality of evidence were assessed following the Cochrane guidelines.

Results:

A total of 22 randomized controlled trials including 1658 patients were included in the meta-analysis. Both International Knee Documentation Committee (IKDC) subjective score and Lysholm score were higher with the independent drilling approach (mean difference [MD], 1.24 [P = .02] and 0.55 [P = .005], respectively). No difference was documented in terms of the risk of reinjury, but independent drilling led to reduced KT-1000 arthrometer–assessed anterior tibial translation (MD, 0.23; P = .01) and a higher probability of a negative postoperative pivot-shift test finding (risk ratio, 1.13; P = .04). There were no significant differences in IKDC objective or Tegner scores. A P value of .07 was found for the association between the year of the study and IKDC objective scores.

Conclusion:

Independent femoral tunnel drilling provided better results than the TT approach, although the difference was not clinically significant. No difference was observed in the risk of reinjury. Increasingly better results were seen among surgical procedures performed in more recent years. Among the independent drilling options, the anteromedial portal technique seemed to provide the most favorable outcomes. The lack of clinically significant differences and the promising outcomes reported with new modified TT techniques suggest the importance of correct placement, rather than the tunnel drilling approach, to optimize the results of ACL reconstruction.

Does radiological evaluation of endobutton positioning in the sagittal plane affect clinical functional results in single-bundle anterior cruciate ligament reconstruction?

INTRODUCTION

Sports injuries are increasing today due to the increased interest in sports. The most common injured knee ligament is the anterior cruciate ligament (ACL) in sport injuries. Accordingly, surgical treatment of the ACL is performed frequently. In this study, it was aimed to retrospectively evaluate whether the location of an endobutton on lateral knee radiography was effective on knee functional scores in patients who underwent ACL reconstruction.

MATERIALS AND METHODS

One hundred thirty patients who underwent ACL reconstruction between January 2015 and February 2019 were identified. The patients were divided into three groups according to the location of the endobutton on lateral radiographs taken in the postoperative period. Group 1 patients were classified as anterior, group 2 as middle, and group 3 as posterior according to the location of the endobutton. Functional scoring, physical examination tests, comparative thigh diameter measurements, and single-leg hop tests were compared between the groups. It was evaluated as to whether there was a statistically significant difference between the groups.

RESULTS

There were 38 patients in group 1, 63 patients in group 2, and 29 patients in group 3. The mean age was 29.1 in group 1, 29.1 in group 2, and 29.7 in group 3. The mean follow-up period of the patients was 18.4 months in group 1, 19.1 months in group 2, and 21.4 months in group 3. The average Lysholm score was 92.9 in group 1, 93.3 in group 2, and 91.7 in group 3. The mean modified Cincinnati scores were 27.0, 27.1, and 26.6, respectively, in the groups. The mean IKDC score of the subjective knee assessments was 92.5, 92.8, and 91, respectively, according to the groups. The average thigh atrophy value was 1 cm, 1 cm, and 1.2 cm, respectively, in the groups. In the single-leg hop test, 34 patients in group 1 jump to over 85% of the distance compared with the intact side, while 58 patients in group 2, and 23 patients in group 3 were successfully able to jump this distance. The effect of the placement of the endobutton in the anterior, middle or posterior was not statistically significant on functional scores and physical examination results. In patients with endobuttons in the middle, functional scores were found better than in those with anterior or posterior placement.

CONCLUSIONS

No statistically significant differences were found in clinical functional results when comparing patients' endobutton location on femur. For this reason, surgical time should not be extended using unnecessary extra effort to change the orientation of the exit hole during surgery.

Risk of arthrofibrosis in anatomical anterior cruciate ligament reconstruction: the role of timing and meniscus suture

BACKGROUND

The optimal timing of anterior cruciate ligament (ACL) reconstruction remains controversial. Several studies have shown that early surgery leads to an increased rate of arthrofibrosis and poorer postoperative function. Other studies found no correlation between time of surgery and arthrofibrosis. The influence of simultaneous meniscus treatment is also discussed. Aim of this study was to ascertain whether the timing of surgery and treatment of meniscus influences the occurrence rate of arthrofibrosis.

METHODS

Two hundred and six patients could be included. These were split into two groups. Group 1: surgery within 6 weeks after ACL rupture (n = 68), group 2: surgery after more than 6 weeks (n = 68). In addition, 2 matched groups were created (n = 138 ). Follow-up was 12 months after surgery. The primary endpoint was the rate of subsequent arthrofibrosis procedures (arthroscopic arthrolysis). Secondary endpoints were knee function (knee osteoarthritis outcome score: KOOS), knee pain (numeric rating scale: NRS) and patient satisfaction measured on a 5 point Likert scale.

RESULTS

In 6 of the 68 patients in group 1 (8.8%) and 3 of the 138 patients in group 2 (2.2%) a subsequent arthroscopic arthrolysis was performed (OR 4.4). A simultaneous meniscal suture was performed in 58 patients (30 of them in group 1). Five of the six patients with subsequent arthrolysis in group 1 received meniscal repair (OR for arthrolysis 3.4). There was no difference between the groups in terms of knee function (KOOS), pain (NRS) and patient satisfaction.

CONCLUSION

The rate of subsequent arthroscopic arthrolysis was higher in the acute surgery group. However, most of these subsequent procedures were associated with meniscal repair at index surgery with a more restrictive rehabilitation protocol than after ACL reconstruction without meniscus repair. This allows the assessment that the meniscal suturing poses an increased risk. Therefore, this allows the conclusion that if using an anatomical surgical technique and considering the signs of inflammation with effusion, pain and movement deficit less than 90° there is no increased risk of arthrofibrosis.

Repair of the Posterior Lateral Meniscal Root Tear: Suture Anchor Fixation Through the Outside-In Anterior Cruciate Ligament Reconstruction Femoral Tunnel

Posterior lateral meniscus root tears are defined as tears that occur within 9 mm of the posterior lateral meniscus insertion or as avulsions of the insertion. If root tears are left unrepaired, functional alterations and early degenerative changes occur in the affected compartment. Several surgical techniques have been described to reattach the posterior horn of the lateral meniscus, including transtibial pull-out technique and side-to-side repair technique. This surgical technique reports an alternative way to repair posterior lateral meniscus root tears that are associated with or without an anterior cruciate ligament graft tear. The technique involves the placement of a suture anchor on the lateral meniscus root footprint through the outside-in anterior cruciate ligament femoral tunnel, which minimizes the possibility of iatrogenic lesions and facilitates repair.

Superior Postoperative Stability and Functional Outcomes With Anteromedial Versus Transtibial Technique of Single-Bundle Autologous Hamstring Anterior Cruciate Ligament Reconstruction: A Meta-analysis of Prospective Randomized Controlled Trials

PURPOSE

The aim of this meta-analysis was to compare the postoperative stability and functional outcomes of anteromedial (AM)- and transtibial (TT)-based single-bundle hamstring anterior cruciate ligament (ACL) reconstruction techniques.

METHODS

A meta-analysis comparing the outcomes of single-bundle hamstring ACL reconstruction using the AM and TT techniques was performed. Prospective randomized controlled trials identified from searches of PubMed, Cochrane, and Embase were included in this review. The outcome measures analyzed included postoperative Lachman test and pivot-shift test results, side-to-side difference, International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity score.

RESULTS

A total of 7 randomized controlled trials (654 patients) were included in this review. The AM technique, compared with the TT technique, resulted in superior postoperative stability based on the negative Lachman test rate (risk ratio [RR], 1.12; 95% confidence interval [CI], 1.01 to 1.24; P = .03; 95% prediction interval [PI], 0.32 to 3.46), negative pivot-shift test rate (RR, 1.16; 95% CI, 1.06 to 1.28; P = .002; 95% PI, 0.40 to 2.88), and side-to-side difference (weighted mean difference [WMD], -0.32 mm; 95% CI, -0.48 to -0.16; P < .0001; 95% PI, -0.55 to -0.09). Likewise, the AM technique contributed to superior postoperative functional outcomes based on the proportion of IKDC grade A findings (RR, 1.16; 95% CI, 1.02 to 1.32; P = .03; 95% PI, 0.40 to 2.83) and the Lysholm score (WMD, 0.82; 95% CI, 0.23 to 1.41; P = .007; 95% PI, -0.22 to 1.86). However, the AM and TT techniques had comparable subjective IKDC scores (WMD, 0.98; 95% CI, -0.91 to 2.88; P = .31; 95% PI, -3.18 to 5.14) and Tegner activity scores (WMD, 0.32; 95% CI, -0.23 to 0.86; P = .25; 95% PI, -3.84 to 4.48).

CONCLUSIONS

The AM method of single-bundle hamstring ACL reconstruction results in superior postoperative stability and functional outcomes compared with the TT method.

LEVEL OF EVIDENCE

Level I, systematic review of Level I studies.

Editorial Commentary: Independent Femoral Tunnel Drilling Avoids Anterior Cruciate Ligament Graft Malpositioning: Advice From a Transtibial Convert

Optimal femoral anterior cruciate ligament graft placement has been extensively studied. The champions of transtibial reconstruction debate the backers of anteromedial portal and outside-in drilling. The holy grail is footprint restoration and how we best to get there. To me, creating the femur independently provides the best chance of finding that footprint by being unconstrained by the tibia. Anterior cruciate ligament surgery is challenging enough; decrease intraoperative stress and increase your likelihood of femoral footprint restoration by drilling it though the anteromedial portal.

ACL Reconstruction Graft Angle and Outcomes: Transtibial vs Anteromedial Reconstruction

BACKGROUND

The importance of creating an anatomic anterior cruciate ligament (ACL) reconstruction has been receiving significant attention. The best technique by which to achieve this anatomic reconstruction continues to be debated. The two most common methods are the transtibial (TT) and anteromedial (AM) techniques. Each has its advantages and disadvantages, and the literature comparing the two remains uncertain.

QUESTIONS/PURPOSES

In this prospective comparative study, we aimed to compare the ACL graft and tunnel angles achieved using the anatomic transtibial (TT) and anteromedial (AM) techniques; compare the ACL graft and tunnel angles in knees that have undergone ACL reconstruction and knees with intact ACLs; and determine whether differences in the graft or tunnel angle produce differences in clinical outcomes, as measured using both physical exam and patient-reported outcomes, after ACL reconstruction.

METHODS

Patients who underwent primary ACL reconstruction with bone-tendon-bone grafts using a TT or AM technique were included. Femoral graft angle (FGA), tibial graft angle (TGA), and sagittal orientation of the reconstructed ACL and contralateral native ACL were measured on post-operative magnetic resonance imaging. Post-operatively, patients underwent measurement of knee stability and completed the Knee Injury and Osteoarthritis Outcome Score (KOOS) survey.

RESULTS

Twenty-nine patients were enrolled (AM group, 14; TT group, 15); at follow-up, KOOS data were available for 26 patients (13 in each group). There were no differences in sagittal ACL graft angle between groups or in comparison with the normal knee. The FGA was more vertical after TT reconstructions; the TGA was comparable between groups. There were no significant differences in 2-year post-operative physical exam measurements or in KOOS scores.

CONCLUSION

Anatomic ACL angle was restored after reconstruction with both the TT and AM techniques, despite different FGAs. No significant differences in clinical outcome were noted between groups on physical exam or KOOS at 2 years after surgery. These results suggest that TT reconstruction results in a graft position similar to that seen in AM reconstruction and that the location of the intra-articular tunnel aperture matters more than the orientation of the tunnel.

[Anterior cruciate ligament injury in adults : Diagnostics and treatment]

The anterior cruciate ligament (ACL) together with the posterior cruciate ligament is the central stabilizer of the knee. It stabilizes the tibia against increased anterior translation and internal rotation. With an incidence of 46/100,000 ACL tears are among the most common sports injuries in Germany. New prevention programs can reduce the risk of ACL injuries. Surgical treatment is recommended for young and athletic patients as it can also reduce the risk of further relevant injuries of the meniscus and cartilage. The standard of surgical treatment in Germany is the ACL reconstruction with an autologous tendon graft. In selected cases, the preservation of the ACL by arthroscopic refixation shows good results. Instead of the previously used purely time-based rehabilitation, function-based criteria are increasingly being included in the aftercare.

Predictive factors for failure of anterior cruciate ligament reconstruction via the trans-tibial technique

INTRODUCTION

Factors for graft failure after trans-tibial (TT) ACL reconstruction, including anterolateral ligament (ALL) injury and degree of synovialization, remain unclear. This study is to evaluate the risk factors for graft failures after TT ACL reconstruction including ALL injury and synovialization.

MATERIALS AND METHODS

A total 391 patients who underwent primary TT ACL reconstruction were included. Failure was defined as greater than grade 2 laxity on the Lachman or pivot shift tests or 5 mm of anterior translation on stress radiograph. After applying inclusion/exclusion criteria, 31 patients with failure were categorized as group 1 and 89 patients without failure were categorized as group 2. Chi-square test and Cox proportional hazard analyses were performed.

RESULTS

Preoperatively, 64 patients had ALL injuries (53.3%), 58 had medial meniscal (MM) tears (48.3%), and 62 had lateral meniscal (LM) tears (51.6%). Ninety-three patients (77.5%) had acute injuries and 27 had chronic injuries as per 6-weeks duration. Significant risk factors for failure were LM tear (hazard ratio [HR], 4.018; 95% confidence interval [CI] 1.677-9.629; p = 0.002), chronicity (HR, 6.812; 95% CI 2.758-16.824; p = 0.000), presence of ALL injury (HR, 3.655; 95% CI 1.442-9.265; p = 0.006), and poor synovialization (HR, 3.134; 95% CI 1.298-7.566; p = 0.011) in Cox proportional hazard analysis. If combined MM and LM tears were found, an increased risk of failure was also identified (combined tears: HR, 3.951; 95% CI 1.754-8.901; p = 0.001/preoperative high-grade laxity: HR, 4.546; 95% CI 1.875-11.02; p = 0.001).

CONCLUSION

Chronic ACL injuries, meniscus tear, preoperative ALL injuries, preoperative high-grade laxity and poor synovialization are significant risk factors. Therefore, these factors should be carefully assessed and properly treated in TT ACL reconstruction.

LEVEL OF EVIDENCE

IV, retrospective cohort study.

Comparative clinical outcomes of anterolateral ligament reconstruction versus lateral extra-articular tenodesis in combination with anterior cruciate ligament reconstruction: systematic review and meta-analysis

BACKGROUND

Anterolateral augmentation procedures can be divided into traditional lateral extra-articular tenodesis (LET) and modern anterolateral ligament (ALL) reconstruction. Nevertheless, no studies have compared the clinical results between LET and ALL reconstruction, when combined with intra-articular ACL reconstruction. This study was therefore designed to compare the clinical results, including the anterior translation, rotational laxity, and patient-reported outcomes, in a group of patients who underwent ACL reconstruction combined with LET or ALL reconstruction.

METHODS

All studies systematically searched until March 2018 without any language restriction that reported the results of a lateral extra-articular stabilization procedure using either LET or ALL reconstruction methods combined with ACL reconstruction were evaluated. Two reviewers independently recorded data from each study, including the sample size, improvement in Lysholm score, and the number of patients with each grade of knee laxity using Lachman and pivot shift tests.

RESULTS

The pooled results of ten studies showed that the postoperative proportion of knees with grade 2 or 3 on the Lachman test was significantly higher following LET compared with ALL reconstruction in combination with ACL reconstruction (10.8%, 95% confidence interval [CI]: 6.6-17.1% vs. 1.5%, 95% CI 0.5-4.5%; p = 0.001). However, the pooled results of 12 studies showed that the proportion of knees that belonged to grade 2 or 3 on the pivot shift test, indicating poor rotational stability, was similar between these two techniques (4.9%, 95% CI 2.0-11.5% vs. 2.3%, 95% CI 1.1-4.5%; p = 0.101). The pooled improvements in Lysholm scores in these two groups were also similar (32.3, 95% CI 26.8-37.9 vs. 25.7, 95% CI 16.7-34.7, p = 0.218).

CONCLUSION

LET could lead to worse anterior instability than with ALL reconstruction when these two approaches were combined with single-bundle ACL reconstruction. However, rotational stability and patient-reported outcomes were similar between the techniques.

Comparative risk-benefit profiles of different femoral drilling techniques in anterior cruciate ligament reconstruction: A protocol for a systematic review and network meta-analysis

BACKGROUND

Anterior cruciate ligament (ACL) injury experiences about 200,000 isolated cases annually, and ACL reconstruction has become the gold standard for the restoration of stability and functionality. In view of that incorrect graft placement is a common cause of ACL reconstruction failure, it is critically important to ensure that the tibial and femoral tunnels are properly placed during the operation. Therefore, we intend to conduct a network meta-analysis to comparatively evaluate the clinical outcomes among the different surgical techniques in ACL reconstruction.

METHODS

Embase, PubMed, and Cochrane Library will be searched through to retrieve the relevant literature up to April 2020. The outcomes include the International Knee Documentation Committee subjective/objective score, Lachman test, Lysholm score, laxity of knee joint, pivot-shift test, Tegner activity scale, and the number of adverse events. A Bayesian hierarchical framework will be used to evaluate the comparative efficacy among different fixation devices. Cochrane Q test and I statistics will be applied to evaluate the heterogeneity, and the Cochrane risk of bias assessment tool will be employed to evaluate the study quality and the risk of bias.

RESULTS

The comparative risk-benefit profiles of different femoral drilling techniques will be evaluated based on the existing evidence, in order to summarize a prioritization regimen.

CONCLUSION

Findings from this network meta-analysis will provide useful reference to patients, surgeons, and guideline makers in the related fields.

REGISTRATION

Open Science Framework (OSF) Preregistration. April 20, 2020. osf.io/uzahs.

Techniques for Femoral Socket Creation in ACL Reconstruction

Anterior cruciate ligament (ACL) injury is common and affects a wide variety of individuals. An ACL reconstruction is the treatment of choice for patients with subjective and objective symptoms of instability and is of particular importance to cutting or pivoting athletes. With many variables involved in ACL reconstruction, femoral tunnel placement has been found to affect clinical outcomes with nonanatomic placement being identified as the most common technical error. Traditionally the femoral tunnel was created through the tibial tunnel or transtibial with the use of a guide and a rigid reaming system. Because of proximal, nonanatomic tunnel placement using the transtibial technique, the use of the anteromedial portal and outside-in drilling techniques has allowed placement of the tunnel over the femoral footprint. In this paper, we discuss the difference between the 3 techniques and the advantages and disadvantages of each. The authors then explore the clinical differences and outcomes in techniques by reviewing the relevant literature.

Anterior cruciate ligament reconstruction with remnant preservation: current concepts

Anterior cruciate ligament (ACL) tears are a common knee injury, and anatomic ACL reconstruction (ACLR) is now the standard of care to restore knee stability. Nevertheless, re-tear rates exceeding 5% are commonly reported, with an even higher percentage of patients unable to achieve preinjury knee function. As the torn ACL remnant contains elements (eg, cells, blood vessels and mechanoreceptors) essential to ACL function, it has been hypothesised that ACLR with remnant preservation may improve graft remodelling, in turn more quickly and completely restoring ACL structure and function. In this Current Concepts review, we summarise the present understanding of ACLR with remnant preservation, which includes selective bundle reconstruction of partial (one-bundle) ACL tears and single- and double-bundle ACLR with minimal to partial debridement of the torn ACL stump. Reported benefits of remnant preservation include accelerated graft revascularisation and remodelling, improved proprioception, decreased bone tunnel enlargement, individualised anatomic bone tunnel placement, improved objective knee stability and early mechanical support (with selective bundle reconstruction) to healing tissues. However, clinical studies of ACLR with remnant preservation are heterogeneous in the description of remnant characteristics and surgical technique. Presently, there is insufficient evidence to support the superiority of ACLR with remnant preservation over the standard technique. Future studies should better describe the ACL tear pattern, remnant volume, remnant quality and surgical technique. Progress made in understanding and applying remnant preservation may inform, and be reciprocally guided by, ongoing research on ACL repair. The goal of research on ACLR with remnant preservation is not only to achieve anatomic structural restoration of the ACL but also to facilitate biologic healing and regeneration to ensure a more robust and functional graft.

Three-Dimensional Magnetic Resonance Imaging for Guiding Tibial and Femoral Tunnel Position in Anterior Cruciate Ligament Reconstruction: A Cadaveric Study

Background:

Femoral and tibial tunnel malposition for anterior cruciate ligament (ACL) reconstruction (ACLR) is correlated with higher failure rate. Regardless of the surgical technique used to create ACL tunnels, significant mismatches between the native and reconstructed footprints exist.

Purpose:

To compare the position of tunnels created by a standard technique with the ones created based on preoperative 3-dimensional magnetic resonance imaging (3D MRI) measurements of the ACL anatomic footprint.

Study Design:

Controlled laboratory study.

Methods:

Using 3D MRI, the native ACL footprints were identified. Tunnels were created on 16 knees (8 cadavers) arthroscopically. On one knee of a matched pair, the tunnels were created based on 3D MRI measurements that were provided to the surgeon (roadmapped technique), while on the contralateral knee, the tunnels were created based on a standard anatomic ACLR technique. The technique was randomly assigned per set of knees. Postoperatively, the positions of the tunnels were measured using 3D MRI.

Results:

On the tibial side, the median distance between the center of the native and reconstructed ACL footprints in relation to the root of the anterior horn of the lateral meniscus medially was 1.7 ± 2.2 mm and 1.9 ± 2.8 mm for the standard and roadmapped techniques, respectively (P = .442), while the median anteroposterior distance was 3.4 ± 2.4 mm and 2.5 ± 2.5 mm for the standard and roadmapped techniques, respectively (P = .161). On the femoral side, the median distance in relation to the apex of the deep cartilage (ADC) distally was 0.9 ± 2.8 mm and 1.3 ± 2.1 mm for the standard and roadmapped techniques, respectively (P = .195), while the median distance anteriorly from the ADC was 1.2 ± 1.3 mm and 4.6 ± 4.5 mm for the standard and roadmapped techniques, respectively (P = .007).

Conclusion:

Providing precise radiological measurements of the ACL footprints does not improve the surgeon’s ability to position the tunnels. Future studies should continue to attempt to provide tools to improve the tunnel position in ACLR.

Clinical Relevance:

This cadaveric study indicates that despite the use of 3D MRI in understanding the ACL anatomy, re-creating the native ACL footprints remains a challenge.

Anatomic ACL reconstruction reduces risk of post-traumatic osteoarthritis: a systematic review with minimum 10-year follow-up

PURPOSE

To systematically review the literature for radiographic prevalence of osteoarthritis (OA) at a minimum of 10 years following anterior cruciate ligament (ACL) reconstruction (ACLR) with anatomic vs. non-anatomic techniques. It was hypothesized that the incidence of OA at long-term follow-up would be lower following anatomic compared to non-anatomic ACLR.

METHODS

A systematic review was performed by searching PubMed, MEDLINE, EMBASE, and the Cochrane Library, for studies reporting OA prevalence by radiographic classification scales at a minimum of 10 years following ACLR with autograft. Studies were categorized as anatomic if they met or exceeded a score of 8 according the Anatomic ACL Reconstruction Scoring Checklist (AARSC), while those with a score less than 8 were categorized as non-anatomic/non-specified. Secondary outcomes included graft failure and measures of knee stability (KT-1000, Pivot Shift) and functional outcomes [Lysholm, Tegner, subjective and objective International Knee Documentation Committee (IKDC) scores]. OA prevalence on all radiographic scales was recorded and adapted to a normalized scale.

RESULTS

Twenty-six studies were included, of which 5 achieved a score of 8 on the AARSC. Using a normalized OA classification scale, 87 of 375 patients (23.2%) had diagnosed OA at a mean follow-up of 15.3 years after anatomic ACLR and 744 of 1696 patients (43.9%) had OA at mean follow-up of 15.9 years after non-anatomic/non-specified ACLR. The AARSC scores were 9.2 ± 1.3 for anatomic ACLR and 5.1 ± 1.1 for non-anatomic/non-specified ACLR. Secondary outcomes were relatively similar between techniques but inconsistently reported.

CONCLUSIONS

This study showed that anatomic ACLR, defined as an AARSC score ≥ 8, was associated with lower OA prevalence at long-term follow-up. Additional studies reporting long-term outcomes following anatomic ACLR are needed, as high-level studies of anatomic ACLR are lacking. The AARSC is a valuable resource in performing and evaluating anatomic ACLR. Anatomic ACLR, as defined by the AARSC, may reduce the long-term risk of post-traumatic OA following ACL injury to a greater extent than non-anatomic ACLR.

LEVEL OF EVIDENCE

IV.

Intraoperative fluoroscopy reduces the variability in femoral tunnel placement during single-bundle anterior cruciate ligament reconstruction

PURPOSE

To evaluate the effect of using intraoperative fluoroscopy on femoral and tibial tunnel positioning variability in single-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

A total of 80 consecutive patients with single-bundle ACL reconstruction between 2014 and 2016 were retrospectively reviewed. Among them, 40 underwent ACL reconstruction without fluoroscopy (non-fluoroscopy group) and 40 underwent fluoroscopy-assisted ACL reconstruction (fluoroscopy group). Femoral and tibial tunnel locations were evaluated using a standardized grid system with three-dimensional computed tomography images. Femoral and tibial tunnel location variability was compared between the groups.

RESULTS

The operation time was longer in the fluoroscopy group than in the non-fluoroscopy group (61.3 ± 5.2 min vs. 55.5 ± 4.5 min, p < 0.001). In the fluoroscopy group, a guide pin was repositioned in 16 (40%) cases on the femoral side and 2 (5%) cases on the tibial side. No significant difference in the femoral tunnel location was observed between the fluoroscopy and non-fluoroscopy groups (anterior-posterior plane, 29.0% ± 3.2% vs. 30.0% ± 6.1%; proximal-distal plane, 30.8% ± 4.8% vs. 29.4% ± 8.3%; all parameters,  n.s.); variability was significantly lower in the fluoroscopy group (p < 0.001 for both anterior-posterior and proximal-distal planes). No significant difference in the tibial tunnel location and variability was observed between the fluoroscopy and non-fluoroscopy groups (medial-lateral plane, 45.8% ± 2.0% vs. 46.6% ± 2.4%; anterior-posterior plane, 31.2% ± 4.0% vs. 31.0% ± 5.4%) (all parameters, n.s.).

CONCLUSIONS

Tunnel positioning with fluoroscopic assistance is feasible and effective in achieving consistency in femoral tunnel placement despite a slightly longer operation time. Intraoperative fluoroscopy can be helpful in cases wherein identifying anatomical landmarks on arthroscopy was difficult or for surgeons with less experience who performed ACL reconstruction.

LEVEL OF EVIDENCE

IV.

Risk analysis of tunnel collision in combined anterior cruciate ligament and anterolateral ligament reconstructions

BACKGROUND

To assess the risk of tunnel collision in combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstructions.

METHODS

Three-dimensional (3D) CT reconstructions of 32 knees after transtibial (TT) (N = 16) or anteromedial portal (AMP) (N = 16) ACL reconstruction were used to simulate potential tunnel collision of the femoral ACL tunnel if combined with a virtual ALL reconstruction. The minimal distance between tunnels, the ALL tunnel length, and the lateral femoral condyle (LFC) width were measured. Moreover, the relationship between the ALL tunnel and the intercondylar notch, trochlear groove and posterior femoral cortex was determined.

RESULTS

The highest rate of tunnel collision (81%) was observed when the ALL tunnel was aimed at 20° in the coronal plane and 0° in the axial plane. However, by aiming the ALL tunnel at 0° coronal and 40° axial angulation, collision was avoided in all patients and no violation of the trochlea was observed. Tunnel collision rate was significantly higher (P = 0.002) when the ACL tunnel was drilled by the AMP technique.

CONCLUSIONS

Risk of tunnel collision was significantly increased when the tunnel was drilled at 0° in the axial plane. Tunnel collision was avoided by aiming the ALL tunnel 40° anteriorly and perpendicular to the anatomical axis of the femur. A more horizontal orientation of the ACL with the AMP technique is a risk factor for tunnel conflicts.

CLINICAL RELEVANCE

ALL tunnel orientation needs to be adjusted to avoid tunnel conflicts in combined ACL-ALL reconstructions.

[A comparative study of arthroscopic anterior cruciate ligament reconstruction via transtibial and transportal techniques]

OBJECTIVE

To investigate the effectiveness of arthroscopic anterior cruciate ligament (ACL) reconstruction via transtibial (TT) and transportal (TP) techniques after 10 years follow-up.

METHODS

A clinical data of 103 patients who underwent arthroscopic ACL reconstruction with a single bundle of autologous hamstring tendon between March 2006 and March 2009 was retrospectively analyzed, among which 57 patients were reconstructed with TT technique (TT group) and 46 patients were reconstructed with TP technique (TP group). There was no significant difference in gender, age, cause of injury, interval between injury and operation, preoperative pivot shift test, preoperative International Knee Documentation Committee (IKDC) score, Lysholm score, and KT-2000 side-to-side difference (SSD) between the two groups ( P>0.05). At 10 years after operation, Lachman test was used to evaluate the forward joint stability and pivot shift test to evaluate the rotational stability of the knee; KT-2000 SSD was used to measure tibial anterior displacement; IKDC score and Lysholm score were used to evaluate knee function; MRI examination was performed to observe graft healing and measure coronal inclination angles of the tibia and femoral tunnels. The rate of return to sports was also calculated.

RESULTS

The incisions healed by first intention in the two groups, and no early complication occurred after operation. All patients were followed up 10-13 years, with an average of 11.5 years. During the follow-up period, there was no limitation of knee extension and flexion, no discomfort of donor site or graft failure in either group. MRI examination showed that the graft healed well. The IKDC score, Lysholm score, and KT-2000 SSD in the two groups were significantly improved after 10 years ( P<0.05), and there was no significant difference between the two groups at 10 years after operation ( P>0.05). There were significant differences in coronal inclination angles of femoral tunnel and tibial tunnel between the two groups ( P<0.05). There was no significant difference in Lachman test and pivot shift test between the two groups ( P>0.05). The rate of return to sports of patients was 61.40% (35/57) in TT group and 63.04% (29/46) in TP group, showing no significant difference between the two groups ( χ 2=0.29, P=0.87).

CONCLUSION

TT and TP techniques can both achieve good effectiveness in ACL reconstruction.

Tunnel placement in ACL reconstruction surgery: smaller inter-tunnel angles and higher peak forces at the femoral tunnel using anteromedial portal femoral drilling-a 3D and finite element analysis

PURPOSE

Recent studies have emphasized the importance of anatomical ACL reconstruction to restore normal knee kinematics and stability. Aim of this study is to evaluate and compare the ability of the anteromedial (AM) and transtibial (TT) techniques for ACL reconstruction to achieve anatomical placement of the femoral and tibial tunnel within the native ACL footprint and to determine forces within the graft during functional motion. As the AM technique is nowadays the technique of choice, the hypothesis is that there are significant differences in tunnel features, reaction forces and/or moments within the graft when compared to the TT technique.

METHODS

Twenty ACL-deficient patients were allocated to reconstruction surgery with one of both techniques. Postoperatively, all patients underwent a computed tomography scan (CT) allowing 3D reconstruction to analyze tunnel geometry and tunnel placement within the native ACL footprint. A patient-specific finite element analysis (FEA) was conducted to determine reaction forces and moments within the graft during antero-posterior translation and pivot-shift motion.

RESULTS

With significantly shorter femoral tunnels (p < 0.001) and a smaller inter-tunnel angle (p < 0.001), the AM technique places tunnels with less variance, close to the anatomical centre of the ACL footprints when compared to the TT technique. Using the latter, tibial tunnels were more medialised (p = 0.007) with a higher position of the femoral tunnels (p = 0.02). FEA showed the occurrence of higher, but non-significant, reaction forces in the graft, especially on the femoral side and lower, however, statistically not significant, reaction moments using the AM technique.

CONCLUSION

This study indicates important, technique-dependent differences in tunnel features with changes in reaction forces and moments within the graft.

LEVEL OF EVIDENCE

II.

Femoral tunnel position in chronic anterior cruciate ligament rupture reconstruction: randomized controlled trial comparing anatomic, biomechanical and clinical outcomes

PURPOSE

The aim of this study was to compare the outcomes between anteromedial (AM) and transtibial (TT) femoral tunnel positioning techniques for the reconstruction of chronic anterior cruciate ligament (ACL) rupture.

MATERIALS AND METHODS

It is a randomized prospective study of 106 patients who underwent ACL reconstruction because of a chronic ACL rupture (55 AMT, 51 TT). Minimum follow-up was 2 years. Demographic, clinical and radiological data, including MRI grafts' anatomy and biomechanics intraoperative navigation system evaluation, were analyzed. Also, International Knee Documentation Committee score, Tegner Knee score, Lysholm Knee Score, Short-Form Health Survey and 4-point Likert Scale were evaluated.

RESULTS

The AM technique achieves a more anatomic graft than TT technique in both sagittal and coronal plane (6° approximately). Immediate postoperative biomechanical evaluation of the graft showed both techniques significantly improved translational and rotational laxity (p = 0.000). AMT showed superiority only in controlling internal rotation (p = 0.016). Both techniques reported significant improvement in all evaluated score scales, without differences between techniques. Independently of the femoral tunnel positioning technique, patients with cartilage lesion had worse clinical outcomes.

CONCLUSIONS

Our findings suggest that AMT achieves a more anatomical and biomechanically accurate graft allowing better control over internal rotation laxity; however, this does not lead to better clinical outcomes if we compare with TT in the reconstruction of chronic ACL rupture. Patients with chronic ACL rupture and cartilage lesion had worse clinical outcomes, independently the femoral tunnel positioning technique.

Effect of Femoral Tunnel Position on Stability and Clinical Outcomes After Single-Bundle Anterior Cruciate Ligament Reconstruction Using the Outside-In Technique

PURPOSE

To evaluate the effects of the femoral tunnel location in the femoral footprint of the anterior cruciate ligament (ACL) on postoperative knee stability and clinical outcomes after ACL reconstruction (ACLR) using the outside-in technique.

METHODS

From December 2012 to August 2014, ACLR was performed using the outside-in technique in 137 patients. Among these patients, those who had a follow-up period of over 2 years were retrospectively reviewed. A total of 102 patients met the inclusion criteria. The relative location of the femoral tunnel in the lateral condyle was evaluated as a percentage using the standardized grid system on a 3-dimensional computed tomography image. Each patient was then classified into the anterior group, center group (anteroposterior plane, 29.3% ± 3.5%), or posterior group depending on the location of the femoral tunnel. Knee laxity was evaluated using a GNRB knee arthrometer, stress radiography, and the pivot-shift test. From a clinical perspective, patient-reported outcomes (International Knee Documentation Committee subjective form and Lysholm knee score) were then evaluated.

RESULTS

Of 102 patients, 31 (30.4%) were assigned to the anterior group, 46 (45.1%) were assigned to the center group, and 25 (24.5%) were assigned to the posterior group. Postoperative side-to-side differences, which were measured using stress radiographs and the GNRB arthrometer, were significantly smaller in the posterior group (1.7 ± 0.6 mm and 1.5 ± 0.5 mm, respectively) than in the center group (2.3 ± 0.9 mm and 2.2 ± 2.8 mm, respectively) and anterior group (2.4 ± 0.7 mm and 2.4 ± 1.3 mm, respectively) (P = .002 for stress radiography and P = .002 for GNRB arthrometer). No significant between-group differences were observed in the pivot-shift test results and patient-reported outcomes among the 3 groups.

CONCLUSIONS

The location of the femoral tunnel in the anatomic ACL footprint did not affect postoperative stability and clinical outcomes in the case of ACLR using the outside-in technique.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Is Anteromedial Drilling Safe in Transphyseal Anterior Cruciate Ligament Reconstruction in Adolescents with Growth Remaining?

BACKGROUND

Previous reports of transphyseal drilling in anterior cruciate ligament (ACL) reconstruction have demonstrated good clinical outcomes without subjective changes in further skeletal development. The purpose of this study is to evaluate radiographic changes during continued growth following a transphyseal ACL reconstruction using an anteromedial femoral (AM) drilling technique in patients with >18 months of growth remaining.

METHODS

A review of consecutive adolescents who underwent a soft tissue transphyseal ACL reconstruction using an AM drilling technique was performed. Inclusion criteria was 18 months of growth remaining based on radiographic bone age and standing radiographs at least one year from the index procedure. Demographic, preoperative, and postoperative data, and follow-up three-foot standing lower extremity radiographs were reviewed. Radiographic data included femoral length, tibial length, total lower extremity length, mechanical axis deviation (MAD), lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA).

RESULTS

In total 12 adolescent patients with a mean age of 13.4 years (range, 12.3 to 14.4) and bone age of 13.4 years (11.5 to 14) at the time of surgery were included. At an average of 2.27-year follow-up (412 to 1058 d), there was no difference in the total growth of the operative and nonoperative limb (48.5 mm vs. 47 mm; P=0.36). In addition, the average increases in femoral length (23.4 mm) and tibial length (25.8 mm) were not statistically different between the operative and the nonoperative limb (P=0.12; P=0.75). There was no statistical difference in mechanical axis deviation, LDFA, or MPTA between preoperative and postoperative radiographs. Mean differences in operative and nonoperative coronal angular changes were all <1.5 degrees.

CONCLUSIONS

With at least 2 years of growth remaining, transphyseal ACL reconstruction with anteromedial drilling did not significantly affect the physis or residual growth compared with the contralateral extremity. Although this technique may create a larger defect in the physis, standing radiographs demonstrate there is no change in limb length or angulation in growing adolescents approximately 2 years after surgery.

LEVEL OF EVIDENCE

This is a case series; Level IV evidence.

Failure to Return to Preinjury Activity Level after Hamstring Anterior Cruciate Ligament Reconstruction: Factors Involved and Considerations in Goal Setting

BACKGROUND

Recent interest in the return to sports, following anterior cruciate ligament reconstruction, has focused on the influence of psychological factors. However, many factors contribute to this endpoint. This study aimed to investigate the ability of nonprofessional athletes to return alongside the reasons for failure.

MATERIALS AND METHODS

We retrospectively studied 101 postreconstruction patients with followup in excess of 12 months. All patients underwent hamstring autograft anterior cruciate reconstruction. The Cincinnati Sports Activity Scale was used to define activity level preinjury, postinjury, and postreconstruction. Structured questionnaires were used to identify factors in those who did not return to the same level.

RESULTS

Seventy percent of patients returned to their preinjury activity score. Of the 30% of patients who failed, age, reconstruction type, and associated pathology were unrelated. However, reconstruction within 6 months of injury resulted in increased return to preinjury score (P < 0.05). Failure was associated with continued knee symptoms (57%), lifestyle changes (27%), anxiety (27%), fear (23%), and other musculoskeletal problems (10%). Considerable interplay was found between these factors. Failure to return was associated with increased further surgery, but this was successful in only one-third of patients.

CONCLUSION

Psychological factors are important (and may require targeted input), but return-to-sport is multifactorial. Ongoing symptoms may prompt further surgery, but this is frequently unsuccessful in achieving return. Patient-specific goals should be sought and revisited throughout the rehabilitation program. Acknowledging psychological barriers, in those aiming to return to the same level, may help achieve this goal. In other patients, success may be return to a desired lower level. Understanding the patient's expectations is important in goal setting.

Anteromedial Portal Drilling Yielded Better Survivorship of Anterior Cruciate Ligament Reconstructions When Comparing Recent Versus Early Surgeries With This Technique

PURPOSE

To compare anteromedial (AM) and transtibial (TT) femoral drilling hole techniques in primary anterior cruciate ligament reconstruction, using the Danish Knee Ligament Reconstruction Register, comparing revision rates and clinical outcomes from 2 time periods, 2007 to 2010 and 2012 to 2015.

METHODS

A total of 8,386 primary anterior cruciate ligament reconstructions were registered between January 2007 to December 2010 and 8,818 in the period January 2012 to December 2015. Revision ACL was the primary endpoint. Secondary endpoints were the objective and subjective clinical outcomes. Crude and adjusted relative risks (RRs) with 95% confidence interval (CIs) were calculated.

RESULTS

The adjusted RR for revision surgery in the AM (2007-10) group compared with the TT (2007-10) group was 1.45 (95% CI, 1.17-1.78; P < .05), but when comparing the AM (2012-15) group with TT (2012-15) group, the RR was 0.99 (95% CI, 0.68-1.45; P = .96). One-year postoperative objective stability testing showed an RR = 1.38 (95% CI, 1.19-1.60; P < .01) for rotational stability and an RR = 1.37 (95% CI, 0.99-1.89; P < .01) for sagittal stability when comparing AM (2007-10) to TT (2007-10). No significant difference in objective stability was found in the more recent period. Lastly, comparing the subjective scores, the AM (2012-15) had a significantly higher Tegner score 1 year postoperatively compared with the TT-group (2012-15).

CONCLUSIONS

This study found an increased RR of revision anterior cruciate ligament and rotational and sagittal instability 1 year postoperatively for the AM technique in the period from 2007 to 2010. However, there was no significant difference in revision surgery and objective measures between the techniques from 2012 to 2015. Nevertheless, a higher activity level was found in the AM group. The results could indicate that the results found in the period 2007 to 2010 may have been caused by a learning curve when introducing a new and more complex procedure (AM).

LEVEL OF EVIDENCE

Level III, retrospective comparative trial.

Anatomic single-bundle anterior cruciate ligament reconstruction using a calcium phosphate-hybridized tendon graft: a randomized controlled trial with 2 years of follow-up

BACKGROUND

To improve tendon-to-bone healing in anterior cruciate ligament (ACL) reconstruction, a novel technique via calcium phosphate (CaP)-hybridized tendon graft using an alternate soaking process was developed. The purpose of this study was to evaluate the clinical results of anatomic single-bundle ACL reconstruction using the CaP-hybridized tendon graft with up to 2 years follow-up, and compare the outcome with conventional ACL reconstruction and preoperative data.

METHODS

Ninety patients who required anatomic single-bundle ACL reconstruction were randomized to undergo either the CaP-hybridized tendon graft method (CaP group, n = 45) or the conventional method (conventional group, n = 45). At 1 and 2 years postoperatively, all patients were evaluated using KT-1000 arthrometry, pivot-shift test, International Knee Documentation Committee (IKDC) grade, Lysholm scale, and Tegner scale; at the same timepoints, bone tunnel enlargement was evaluated using computed tomography, and the tendon graft intensity was evaluated on magnetic resonance imaging. Tendon graft appearance was evaluated arthroscopically once after a period of up to 2 years postoperatively. Cases of re-rupture and adverse events were recorded in both groups.

RESULTS

In both groups, the KT-1000 arthrometry, pivot-shift test, IKDC grade, and Lysholm scale results at 1 and 2 years postoperatively were superior to preoperative data; these results did not significantly differ between groups at either timepoint. The rate of increase of the cross-sectional area of the femoral bone tunnel in the CaP group was smaller than that in the conventional group at 1 year postoperatively. The other results did not significantly differ between the two groups at any timepoint. There were two cases of re-rupture in the CaP group, and six cases of re-rupture in the conventional group. There were no adverse events during follow-up in either group.

CONCLUSIONS

Anatomic single-bundle ACL reconstruction using a CaP-hybridized tendon graft was safe, and resulted in improved clinical outcomes at 2 years postoperatively compared with preoperative data; the outcomes were comparable with the conventional method. A longer follow-up is needed to clarify the clinical effects of the CaP-hybridized tendon graft in anatomic single-bundle ACL reconstruction.

TRIAL REGISTRATION

UMIN, UMIN000019788 Registered 14 November 2015-Retrospectively registered.

Comparison of 2 femoral tunnel drilling techniques in anterior cruciate ligament reconstruction. A prospective randomized comparative study

BACKGROUND

To evaluate the length and position of femoral tunnel,and exam whether knee stability and clinical functional outcomes are superior in AMP method.

METHODS

From August 2014 to February 2015, we prospectively recruited 104 patients undergoing anterior cruciate ligament reconstruction. They were randomized to anteromedial portal or transtibial method. All patients underwent Lysholm score, International Knee Documentation Committee score,Tegner score at pre-operative and last follow-up point as subjective assessment of clinical function. The Lachman test, the Pivot-shift test and KT-1000 were performed at the last follow-up as a evaluation of knee joint stability. We measured the length of femoral tunnel intraoperatively and at 1 week post-operatively, CT-based three-dimensional reconstruction was used to assess femoral tunnel location.

RESULTS

The average follow-up time of anteromedial portal group was 25.7 ± 6.8 months (range:12-36.5 months), and the average follow-up time of the transtibial group was 24.9 ± 6.0 months (range:12-37 months). There was no significant difference between the groups pre-operative Lysholm score, IKDC score and Tegner scores. Both groups showed significantly improvement in these clinical function scores at follow up for their ACL reconstruction. However, there was no significant difference in the function scores between the two groups at last follow up. However, the mean femoral tunnel length in the anteromedial portal group was significantly shorter than that in the transtibial group. And tunnel location was significantly lower and deeper with the anteromedial portal technique than with the transtibial technique.

CONCLUSION

The use of anteromedial portal method resulted in a significantly lower and deeper placement of the femoral tunnel, and a shorter tunnel length compared to the transtibial method. However, there was no statistical difference in terms of clinical function and knee joint stability between the anteromedial portal method and the transtibial method.

TRIAL REGISTRATION

Name of the registry: Chinese Clinical Trial Registry. The registration number: ChiCTR1800014874 . The date of registration: 12 February, 2018. The study is retrospectively registered.

Tibiofemoral joint contact area and stress after single-bundle anterior cruciate ligament reconstruction with transtibial versus anteromedial portal drilling techniques

Background

During single-bundle ACLR, femoral tunnel location plays an important role in restoring the intact knee mechanisms, whereas malplacement of the tunnel was cited as the most common cause of knee instability. The objective of this study is to evaluate, objectively, the tibiofemoral contact area and stress after single-bundle (SB) anterior cruciate ligament reconstruction (ACLR) with femoral tunnel positions drilled by transtibial (TT) or anteromedial (AM) portal techniques.

Methods

Seven fresh human cadaveric knees underwent ACLR by the use of TT or AM portal techniques in a randomized order. These specimens were reused for ACL-R (TT and AM). The tibiofemoral contact area and stresses were gauged by an electronic stress-sensitive film inserted into the joint space. The knee was under the femoral axial compressive load of 1000 N using a biomechanics testing machine at 0°, 10°, 20°, and 30° of flexion. Three conditions were compared: (1) intact ACL, (2) ACLR by the use of the TT method, and (3) ACLR by the use of the AM portal method.

Results

Compared with AM portal ACL-reconstructed knees, a significantly decreased tibiofemoral contact area on the medial compartment was detected in the TT ACL-reconstructed knees at 20°of knee flexion (P = .047). Compared with the intact group, the TT ACLR group showed a higher mean stress at 20° and 30° of flexion on the medial compartments (P = .001, P = .003, respectively), while the AM portal ACLR group showed no significant differences at 30° of flexion (P = .073). The TT ACLR group also showed a higher mean maximum stress at 20° of flexion on the medial compartments (P = .047), while the AM portal ACLR group showed no significant differences at this angle(P = .319).

Discussion

The alternation of the tibiofemoral joint contact area and stress in reconstructed knees may be caused by the mismatch of the tibiofemoral joint during knee movement procedures compared with intact knees.

Conclusions

SB ACLR by the use of the AM portal method and TT method both alter the tibiofemoral contact area and stress when compared with the intact knee. When compared with the TT technique, ACLR by the AM portal technique more closely restores the intact tibiofemoral contact area and stress at low flexion angles.

Editorial Commentary: Does "No Difference" Really Mean "No Difference"? Not All Anterior Cruciate Ligament Transtibial Drilling Techniques Are Created Equal

Despite the preponderance of biomechanical data suggesting that independent femoral tunnel drilling results in more favorable knee kinematics and superior anterior cruciate ligament footprint restoration when compared with transtibial tunnel drilling, equivalent clinical outcomes associated with both techniques continue to be reported. However, readers could contemplate the meaning of "clinical equivalence" and, perhaps, find themselves wanting better ways to detect differences between surgical techniques.

New Trends in Anterior Cruciate Ligament Reconstruction: A Systematic Review of National Surveys of the Last 5 Years

The purpose of this study was to analyze national surveys of orthopaedic surgeons on anterior cruciate ligament (ACL) reconstruction to determine their preferences related to the preferred graft, femoral tunnel positioning, fixation and tensioning methods, antibiotic and anti-thromboembolic prophylaxis, and use of tourniquet and drains. A systematic search of PubMed, Web of Science, and Cochrane Library was performed. Inclusion criteria were surveys of ACL reconstruction trends and preferences published in the past 5 years (2011–2016), involving members of national societies of orthopaedics. Information regarding survey modalities, population surveyed, graft choice both in the general or in the athletic population, surgical technique, fixation, use of antibiotic, tourniquet, drains, and anti-thromboembolic prophylaxis was extracted. Eight national surveys were included from Europe (three), North or Latin America (three), and Asia (two). Overall, 7,420 questionnaires were sent, and 1,495 participants completed the survey (response rate ranging from 16 to 76.6%). All surveys reported the hamstring tendon (HT) autograft as the preferred graft, ranging from 45 to 89% of the surveyed population, followed by bone-patellar tendon-bone (BPTB) graft (2–41%) and allograft (2–17%). Only two surveys focusing on graft choice in athletic population underlined how in high-demand sportive population the graft choices changes in favor of BPTB. Single-bundle reconstruction was the preferred surgical technique in the four surveys that investigated this issue. Five surveys were in favor of anteromedial (AM) portal and two in favor of trans-tibial technique. Suspension devices for femoral fixation were the preferred choice in all but one survey, while interference screws were the preferred method for tibial fixation. The two surveys that investigated graft tensioning were in favor of manual tensioning. The use of tourniquet, antibiotics, drains, and anti-thromboembolic prophylaxis were vaguely reported. A trend toward the preference of HT autograft was registered in all the surveys; however, sport participation has been highlighted as an important variable for increased use of BPTB. Single-bundle reconstruction with AM portal technique and suspension femoral fixation and screws fixation for the tibia seem the preferred solution. Other variables such as tensioning, antibiotic, anti-thromboembolic prophylaxis, tourniquet use, and drains were investigated scarcely among the surveys; therefore, no clear trends could be delineated. This is a Level V, systematic review of expert opinion study.

Modified transtibial versus anteromedial portal techniques for anterior cruciate ligament reconstruction, a comparative study

PURPOSE

This study compared the accessory anteromedial portal (AAMP) and the modified transtibial technique (MTTT)" for single-bundle anterior cruciate ligament (ACL) reconstruction.

PATIENTS AND METHODS

Sixty active adult patients with ACL tear were randomly assigned into two equal groups who were treated surgically. One group was operated on using AAMP and the other group through MTTT. Both the groups had the same postoperative course and were followed for 1 year after surgery. The follow-up included Lysholm and International Knee Documentation Committee (IKDC) subjective knee evaluation forms, IKDC objective knee examination form, and radiological evaluation. Results were evaluated and compared with each other.

RESULTS

There was no significant difference in subjective effects or clinical examination between the two groups. Regarding radiological angles, the AAMP had more oblique graft orientation in the coronal plane than the MTTT, but both were found to be more slanted than native ACL. Also, the MTTT had succeeded to place the graft and tunnel more obliquity than the traditional non-anatomic TTT and better than the anatomic ranges despite having the graft inclination of the AAMP higher than the MTTT. The complaints from the patients and subjective scoring were found to be positively related to graft stability. Patients with healthier preoperative subjective state had a smoother postoperative period and better outcome.

CONCLUSION

This study offers simple modifications to the transtibial technique to allow near anatomic ACL reconstruction with similar results comparable to the AAMP and with fewer complications.