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

Reliability and changes in knee cartilage T2 relaxation time from 6 to 24 months after anatomic anterior cruciate ligament reconstruction

The objectives of this study were to evaluate the reliability of cartilage T2 relaxation time measurements and to identify focal changes in T2 relaxation on the affected knee from 6 to 24 months after anatomic anterior cruciate ligament reconstruction (ACLR). Data from 41 patients who received anatomic ACLR were analyzed. A bilateral 3.0-T MRI was acquired 6 and 24 months after ACLR. T2 relaxation time was measured in subregions of the femoral condyle and the tibial plateau. The root-mean-square coefficient of variation (RMSCV) was calculated to evaluate the reliability of T2 relaxation time in the contralateral knee. Subregion changes in the affected knee T2 relaxation time were identified using the contralateral knee as a reference. The superficial and full thickness layers of the central and inner regions showed good reliability. Conversely, the outer regions on the femoral side and regions in the deep layers showed poor reliability. T2 relaxation time increased in only 3 regions on the affected knee when controlling for changes in the contralateral knee, while changes in T2 relaxation time were identified in 14 regions when not using the contralateral knee as a reference. In conclusion, evaluation of cartilage degeneration by T2 relaxation time after ACLR is most reliable for central and inner cartilage regions. Cartilage degeneration occurs in the central and outer regions of the lateral femoral condyle from 6 to 24 months after anatomic ACLR.

Femoral Tunnel Position in Anatomical Double-bundle ACL Reconstruction is not Affected by Blumensaat's Line Morphology

The aim of this study was to reveal the influence of the morphological variations of the Blumensaat's line on anteromedial (AM) and posterolateral (PL) femoral tunnel position in anatomical double-bundle anterior cruciate ligament (ACL) reconstruction.Fifty-three subjects undergoing anatomical double-bundle ACL reconstruction were included (29 female, 24 male; median age 27.4 years; range: 14-50 years). Using an inside-out transportal technique, the PL tunnel position was made on a line drawn vertically from the bottommost point of the lateral condyle at 90 degrees of knee flexion, spanning a distance of 5 to 8 mm, to the edge of the joint cartilage. AM tunnel position was made 2 mm distal to the PL tunnel position. Following Iriuchishima's classification, the morphology of the Blumensaat's line was classified into straight and hill (large and small) types. Femoral tunnel position was determined using the quadrant method. A Mann-Whitney U test was performed to compare straight and hill type knees according to AM and PL femoral tunnel position.There were 18 straight and 35 hill type knees (13 small and 22 large hill). AM and PL femoral tunnel position in straight type knees were 21.7 ± 7.0 and 33.6 ± 10.5% in the shallow-deep direction, and 42.1 ± 11.1 and 72.1 ± 8.5% in the high-low direction, respectively. In hill type knees, AM and PL femoral tunnel position were 21.3 ± 5.8 and 36.9 ± 7.1% in the shallow-deep direction, and 44.6 ± 10.7 and 72.1 ± 9.7% in the high-low direction, respectively. No significant difference in AM or PL femoral tunnel position was detected between straight and hill type knees.AM and PL femoral tunnel position in anatomical double-bundle ACL reconstruction was not affected by the morphological variations of the Blumensaat's line. Surgeons do not need to consider Blumensaat's line morphology if AM and PL femoral tunnel position is targeted at the bottommost point of the lateral condyle. This was a level of evidence III study.

Tibial spine volume is smaller in ACL-injured athletes compared to healthy athletes

PURPOSE

The aim of this study was to investigate whether the whole tibial spine volume and femoral intercondylar notch volume are risk factors for anterior cruciate ligament (ACL) injury. The hypothesis was that the whole tibial spine volume and femoral notch volume would be smaller in athletes who sustained ACL injury than in athletes with no history of ACL injury.

METHODS

Computed tomography scans of both knees were acquired and three-dimensional bone models were created using Mimics to measure whole tibial spine volume and femoral notch volume. Tibial spine volume, femoral notch volume and each of these volumes normalised by tibial plateau area were compared between the ACL-injured and the ACL-intact group.

RESULTS

Fifty-one athletes undergoing unilateral anatomical ACL reconstruction (17 female, 34 male: average age 22.0 ± 7.5) and 19 healthy collegiate athletes with no previous knee injury (eight female, 11 male: average age 20.1 ± 1.3) were included in this study. The whole tibial spine volume in the ACL-injured group (2.1 ± 0.5 cm3) was 20.7% smaller than in the ACL-intact group (2.7 ± 0.7 cm3) (p = 0.005). No differences were observed between the femoral notch volume in the ACL-injured group (9.5 ± 2.1 cm3) and the ACL-intact group (8.7 ± 2.7 cm3) (n.s.).

CONCLUSIONS

The main finding of this study was that the whole tibial spine volume of the ACL-injured group was smaller than the ACL-intact group. A small tibial spine volume can be added to the list of anatomical risk factors that may predispose athletes to ACL injury.

LEVEL OF EVIDENCE

Level Ⅲ.

Anterior Cruciate Ligament-Injured Knees With Meniscal Ramp Lesions Manifest Greater Anteroposterior and Rotatory Instability Compared With Isolated Anterior Cruciate Ligament-Injured Knees

PURPOSE

To investigate the effects of ramp lesion (RL) and its repair on knee instability in patients with anterior cruciate ligament (ACL) injury by quantitatively assessing anteroposterior and rotational knee instability before and after ACL reconstruction.

METHODS

All primary double-bundle ACL reconstructions using hamstring autografts between 2016 and 2021 were evaluated retrospectively. Patients with RLs without other meniscal injuries were included in group R, whereas those with isolated ACL injuries constituted group C. RL was repaired using all-inside devices in all patients in group R. Knee instability, including the amount of anterior tibial translation (ATT), and the acceleration and external rotational angular velocity of the knee joint (ERAV) during the pivot-shift test were assessed at the time of surgery. The pivot-shift test grade was recorded.

RESULTS

A total of 73 patients were included in this study. Preoperatively, group R (n = 23) had significantly greater pivot-shift grades (P = .039), ATT (6.0 mm, group R; 4.5 mm, group C, P < .001), acceleration (6.8, 2.8; P = .037), and ERAV (3.9, 2.8; P = .001) than group C (n = 50). Intraoperatively, ATT (-1.0 mm, -1.0 mm; P < .001), acceleration (1.2, 1.1; P < .001), and ERAV (1.4, 1.2; P < .001) were significantly decreased compared with the preoperative values in both groups. No significant differences in these values were observed between groups R and C.

CONCLUSIONS

ACL-injured knees accompanied by RLs exhibited significantly greater anteroposterior and rotatory instability than knees with isolated ACL injuries; increased knee instability can be effectively addressed by performing RL repair in conjunction with ACL reconstruction. The quantitative assessments employed-specifically measuring ATT, acceleration, and ERAV during the pivot-shift test-have allowed us to delineate these aspects of knee instability with greater precision.

LEVEL OF EVIDENCE

Level Ⅲ, retrospective comparative study.

3D visualization of the human anterior cruciate ligament combining micro-CT and histological analysis

PURPOSE

The study aimed to obtain a comprehensive 3D visualization of knee specimens, including the cruciate ligaments and corresponding femoral and tibial bone insertions using a non-destructive micro-CT method.

METHODS

Knee specimens were fixed in anatomical positions and chemically dehydrated before being scanned using micro-CT with a voxel size of 17.5 μm. RGBA (red, green, blue, alpha) transfer functions were applied to virtually colorize each structure. Following micro-CT scanning, the samples were rehydrated, decalcified, and trimmed based on micro-CT 3D reconstructions as references. Histological evaluations were performed on the trimmed samples. Histological and micro-CT images were registered to morphologically and densitometrically assess the 4-layer insertion of the ACL into the bone.

RESULTS

The output of the micro-CT images of the knee in extension and flexion allowed a clear differentiation of the morphologies of both soft and hard tissues, such as the ACL, femoral and tibial bones, and cartilage, and the subsequent creation of 3D composite models useful for accurately tracing the entire morphology of the ligament, including its fiber and bundle components, the trajectory between the femur and tibia, and the size, extension, and morphology of its insertions into the bones.

CONCLUSION

The implementation of the non-destructive micro-CT method allowed complete visualization of all the different components of the knee specimens. This allowed correlative imaging by micro-CT and histology, accurate planning of histological sections, and virtual anatomical and microstructural analysis. The micro-CT approach provided an unprecedented 3D level of detail, offering a viable means to study ACL anatomy.

Anatomic Double-Bundle and Single-Bundle Reconstructions Yield Similar Outcomes Following Anterior Cruciate Ligament Rupture: A Systematic Review and Meta-analysis

PURPOSE

To evaluate outcomes of arthroscopic single-bundle (SB) versus anatomic double-bundle (ADB) anterior cruciate ligament reconstruction (ACLR) in adults through a synthesis of randomized controlled trials (RCTs). We hypothesized that SB and ADB methods would lead to similar outcomes after reconstruction of ACL rupture.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses checklist guided our reporting. To identify RCTs that compared SB and ADB reconstructions, a thorough literature search was conducted of PubMed, Embase, Cochrane library, and Web of Science. The methodologic quality of each included study was independently assessed by 2 authors using the Cochrane Collaboration's risk of bias tool. The Anatomic ACL Reconstruction Scoring Checklist (AARSC) was used to screen the eligibility of each study's operative approaches. Twelve clinical outcomes were investigated through pooled analyses conducted using Review Manager 5.3.

RESULTS

This meta-analysis synthesized 13 RCTs comparing postoperative outcomes between ADB and SB reconstructions of ACLs. After a minimum follow-up of 12 months, ADB and SB technique resulted in similar subjective clinical outcomes, including the International Knee Documentation Committee subjective score, Lysholm score, Tegner activity score, and Knee injury and Osteoarthritis Outcome Score sports subscale. Similarly, no statistically significant outcomes were found for objective outcomes such as International Knee Documentation Committee objective grade, pivot-shift test, Lachman test, side-to-side difference, extension deficit, flexion deficit, and osteoarthritis change. However, patients who underwent SB reconstruction had significantly greater complication rates than those that underwent ADB reconstruction.

CONCLUSIONS

When an ACLR approach meets a minimal total AARSC score of 8, ADB and SB techniques may result in similar subjective and objective outcomes, but the ADB technique may lead to lower complication rates following surgery. We recommend that surgeons favor ADB ACLR, as guided by the AARSC.

LEVEL OF EVIDENCE

Level I, systematic review and meta-analysis of Level I randomized controlled trials.

Double-bundle anterior cruciate ligament reconstruction in patients aged 60 years and older

Background

This study aimed to examine the clinical outcomes of double-bundle (DB) anterior cruciate ligament (ACL) reconstruction in patients aged ≥60 years.

Methods

Anatomical DB-ACL reconstruction using hamstring tendon autografts was performed in 13 patients aged ≥60 years at our institution between June 2012 and May 2018. The patients included seven men and six women, and the mean age at surgery was 65.0 years (range, 60-73 years). The mean time from injury to surgery was 80.5 months (range, 1-480 months), and the mean follow-up time was 26.2 months (range, 24-42 months). All patients were assessed based on physical examination findings, clinical scores, Kellgren-Lawrence grades preoperatively and at the final postoperative follow-up, intraoperative meniscal or chondral lesions, and perioperative complications. Status of returning to sports for all patients was assessed at the final follow-up.

Results

The mean side-to-side differences by arthrometer improved from 4.3 mm (range, 2-8 mm) to 0.9 mm (range, 0-2 mm), and the positive pivot-shift test decreased from 100% to 8%. The mean extensor muscle strength was 93.3% (range, 74-116%) postoperatively. The mean Lysholm score improved from 71.1 (range, 27-85) to 95.2 (range, 89-100). Ten of the 13 patients (77%) returned to their pre-injury level of sports performance, and one patient (8%) returned to sports with less intensity. Intraoperatively, meniscal tears were observed in 10 patients (77%), and chondral lesions >grade 2 were observed in 11 (85%). One patient developed perioperative complications. At the final follow-up, the Kellgren-Lawrence grade worsened in only one patient. No re-injury or infection was observed, and revision surgery was not required for any patients.

Conclusions

Anatomical DB-ACL reconstruction could provide satisfactory clinical outcomes and knee function restoration in patients aged ≥60 years.

Level of evidence

A retrospective study, case series (IV).

Adverse Events and Complications After Primary ACL Reconstruction With Quadriceps Tendon Autograft: A Systematic Review

Background

Anterior cruciate ligament reconstruction (ACLR) surgery with quadriceps tendon (QT) grafts, both with and without a patellar bone plug, have gained popularity in recent years in the primary and revision settings. Postoperative complications occur with the use of QT autografts.

Purpose

To systematically review the incidence of postoperative complications after primary ACLR QT autograft and compare complication rates in patients undergoing all-soft tissue QT grafts versus QT grafts with a patellar bone plug (QTPB).

Study Design

Systematic review; Level of evidence, 4.

Methods

A literature search using the 2020 PRISMA guidelines was performed by querying PubMed, Embase, and Scopus databases from database inception through August 2022. Included were evidence level 1 to 4 human clinical studies in English that reported complications after primary ACLR with QT autograft. The incidence of complications within the included studies was extracted. Differences in the incidence of postoperative complications between ACLR with QT with and without a patellar bone plug were calculated.

Results

A total of 20 studies from 2004 to 2022, comprised of 2381 patients (2389 knees; 68.3% male) with a mean age of 27 years (range, 12-58 years), were identified. The mean follow-up was 28.5 months (range, 6-47 months). The total incidence of complications was 10.3%, with persistent postoperative knee pain being the most common (10.8%). Patients who underwent ACLR with all-soft tissue QT grafts had a 2.7-times increased incidence of anterior knee pain (23.3% vs 8.6%) and reoperations (5.9% vs 3.2%) when compared with QTPB grafts (P < .01 for both). There was no appreciable difference in total complications, graft failures, ACLR revisions, cyclops lesions, or range of motion deficit (P > .05 for all). Patellar fractures occurred exclusively after QTPB (2.2%).

Conclusion

Complications after primary ACLR using QT autograft were recorded in 10.5% of knees, with anterior knee pain being the most common. No difference was reported in the overall incidence of complications with the use of the QT versus QTPB grafts; however, anterior knee pain was 2.7 times greater with use of a soft tissue quadriceps graft.

Current development in surgical techniques, graft selection and additional procedures for anterior cruciate ligament injury: a path towards anatomic restoration and improved clinical outcomes-a narrative review

Background and Objective

Anterior cruciate ligament (ACL) reconstruction has been widely used for ACL injury for a long time. However, residual rotational instability and osteoarthritic changes after ACL reconstruction have been identified as problems. Thus, anatomic reconstruction techniques, various types of grafts and additional procedures have been desired to improve the clinical outcomes and knee instability. Although clinical outcomes and knee stability are better than in the past, ipsilateral graft failures still occur in 4-17% and osteoarthritic changes are seen in about 20% of patients after ACL reconstruction. To remedy these problems, it is necessary to improve the understanding of various surgical techniques and grafts and to pursue further improvement of surgical techniques. Therefore, the objective of this review is to summarize the advantages and disadvantages of various surgical techniques and graft selection, and additional procedures for ACL injury.

Methods

A literature review was conducted on the surgical procedures for ACL injury. Recent trends in surgical techniques, graft selection, and additional procedures for ACL injury were described. We performed a literature search in PubMed for studies published from origin to May 8, 2023. Studies were required to be English-language articles.

Key Content and Findings

Although many reports indicate that double-bundle ACL reconstruction is comparable to anatomic single-bundle (SB) reconstruction, intraoperative complications such as tunnel coalition exist in double-bundle reconstruction, and the technique needs to be improved. ACL repair has shown good short-term results, but long-term results need to be examined in the future. Quadriceps tendon autograft is being used more frequently, but hamstrings tendon autograft and bone-patellar tendon-bone autograft also have good results. In addition, in higher-risk cases, lateral extra-articular tenodesis (LET) and anterolateral ligament (ALL) reconstruction can be performed with good results.

Conclusions

To further improve clinical outcomes, more anatomical reconstructions should be pursued. Autografts are better than allografts and synthetic grafts, but further study is needed to determine which graft is better. Additional procedures should be performed in highly unstable cases and in revision cases.

Double-Versus Single-Bundle Anterior Cruciate Ligament Reconstructive Surgery: A Prospective Study With >1 Year Follow-Up

Background The increased prevalence of knee trauma predominantly adds to the anterior cruciate ligament (ACL) tear frequencies that require single- or double-bundle reconstructive surgeries. Few studies have demonstrated the superior results of double-bundle reconstruction compared to single-bundle approaches. This study investigated the knee function improvement capacity of both reconstruction techniques in patients with ACL tears. Methods Thirty cases with ACL tears have been enrolled and segregated equally in distinct (single-bundle versus double-bundle) batches. The diagnostic assessments were undertaken through comprehensive clinical history, knee radiographs, Lysholm scoring, the International Knee Documentation Committee (IKDC) scale, the Lachman analysis, the International Knee Documentation Committee (IKDC) scale, and the pivot shift method. Results After one year, there was a significant enhancement in the postoperative versus preoperative Lysholm scores in the single-bundle (58.5 ± 21.2 vs. 82.4 ± 26.2, p<0.001) and double-bundle (86.4 ± 22.8 vs 60.3 ± 19.2, p<0.001) groups. There was a significant improvement in the IKDC scores after a follow-up period of one year (p-value: 0.012 and p-value: 0.002, respectively) in both of the study batches. After a year of follow-up, Lysholm scores (p=0.352) and IKDC scores (p=0.574) between the study groups (82.4 ± 26.2 vs. 86.4 ± 22.8) were comparable. Conclusion The clinical outcomes remained comparable between subjects with single-bundle reconstruction versus double-bundle reconstruction subjects with ACL injuries. Findings were similar between the groups after one year and two years of surgical interventions.

Persistent knee extension deficits are common after anterior cruciate ligament reconstruction: a systematic review and meta-analysis of randomised controlled trials

PURPOSE

Knee extension deficits complicate recovery from ACL injury and reconstruction; however, the incidence of knee extension loss is not well defined. The aim of this review was to identify the incidence of loss of extension (LOE) following ACL rupture and reconstruction, explore the definitions of knee extension deficits reported and identify prognostic factors affecting LOE incidence.

METHODS

A systematic search was conducted in Medline, Cochrane Library and PEDro for studies in publication up to November 2021, with no restrictions on publication year. References were screened and assessed for inclusion using predetermined eligibility criteria. Randomised controlled trials (RCTs) that quantified knee angle, loss of extension or incidence of extension deficit were included for quality assessment and data extraction. Statistical summaries were generated and meta-analyses performed in two parts to examine: (i) the probability of a datapoint being zero incidence compared to a nonzero incidence and (ii) the relationship between the predictors and nonzero LOE incidence.

RESULTS

A sample of 15,494 studies were retrieved using the search criteria, with 53 studies meeting eligibility criteria. The pooled results from 4991 participants were included for analysis, with 4891 participants who had undergone ACLR. The proportion of included studies judged at an overall low risk of bias was small (7.8%). The observed group and study were the most important predictors for whether a datapoint reported an incidence of extension deficit. Time to follow-up (P < 0.001) and graft type (P = 0.02) were found to have a significant influence on nonzero LOE incidence (%). Covariate adjusted estimates of average LOE indicated 1 in 3 patients presenting with LOE at 12 month follow-up, reducing to 1 in 4 at 2 years.

CONCLUSIONS

This review examined the definitions for the measurement and interpretation of postoperative knee extension and established the trajectory of knee extension deficit after ACL injury and reconstruction. While factors associated with loss of extension were identified, the exact trajectory of knee extension deficits was difficult to infer due to discrepancies in measurement techniques and patient variation. On average, 1 in 3 patients may present with loss of extension of at least 3 degrees at 12-month follow-up, decreasing to 1 in 4 at 2 years. These results may be used by clinicians as an upper threshold for acceptable complication rates following ACLR. Future work should focus on LOE as a clinically relevant complication of ACL injury and treatment with appropriate attention to standardisation of definitions, measurements and better understanding of natural history.

PROSPERO REGISTRATION NUMBER

CRD42018092295.

LEVEL OF EVIDENCE

Level I.

Untreated Injuries to the Anterolateral Capsular Structures Do Not Affect Outcomes and Kinematics after Anatomic Anterior Cruciate Ligament Reconstruction

BACKGROUND

Injuries to the anterolateral complex (ALC) may contribute to increased rotatory knee laxity. However, it has not been evaluated whether such injuries affect in vivo kinematics when treated in situ. The purpose of this study was to determine the grade of ALC injury and its effect on kinematic and clinical outcomes of ACL-injured patients 24 months after anatomic ACL reconstruction. It was hypothesized that injury to the ALC would be significantly related to patient-reported outcomes (PROs) and in vivo knee kinematics during downhill running.

METHODS

Thirty-five subjects (mean age: 22.8 ± 8.5 years) participating in a randomized clinical trial to compare single- and double-bundle ACL reconstruction were included in the study. Subjects were divided into two groups based on the presence or absence of injury to the ALC, as determined on MRI scans performed within 6 weeks of injury. None of the patients underwent treatment for these ALC injuries. At 24 months, PROs, including the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF), Knee injury and Osteoarthritis Outcome Score (KOOS) and in vivo knee kinematics during downhill running, were obtained. Pivot-shift test results, PROs and in vivo knee kinematics were compared between groups with and without ALC injury using the Pearson's Chi Squared test and Mann-Whitney U test with significance set at p < 0.05.

RESULTS

The average interval between injury and performing the MRI scans was 9.5 ± 10 days. ALC injury was observed in 17 (49%) study participants. No significant differences were detected in PROs and in vivo kinematics between subjects with and without ALC injury (n.s.).

CONCLUSION

The findings of this study demonstrate that MRI evidence of an ALC injury does not significantly affect in vivo knee kinematics and PROs even in individuals with a high-grade ALC injury. Injuries to the ALC as observed on MRI might not be a useful indication for an anterolateral procedure.

Rebranding the 'anatomic' ACL reconstruction: Current concepts

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

Less than 1% risk of donor-site quadriceps tendon rupture post-ACL reconstruction with quadriceps tendon autograft: a systematic review

PURPOSE

The purpose of this study is to develop a comprehensive complications profile for quadriceps tendon-autograft anterior cruciate ligament reconstruction (QT ACL-R).

METHODS

A traditional and grey literature search was conducted in accordance with PRISMA and R-AMSTAR guidelines. PubMed, EMBASE, MEDLINE, CINAHL, Cochrane, Web of Science, and many grey literature sources were searched from inception to May 29, 2022. All studies were searched and screened in duplicate with included studies being of all levels of evidence, reporting complications, and with patients of all ages undergoing primary ACL reconstruction with quadriceps tendon autograft in the last 15 years. Studies were excluded if they had cadaveric or animal subjects or were reviews. Risk of bias assessment was conducted using MINORS criteria for non-randomised studies and Cochrane's RoB 2.0 for randomised studies. Data were summarised with weighted event rates generated under a random-effects model.

RESULTS

A total of 55 studies (5315 reconstructions) were included: 32 used quadriceps tendon with bone block (B-QT), 19 used all-soft tissue quadriceps tendon (S-QT), and four did not report the QT graft subtype used. Included patients had an age range of 6.2-58 years and an average reported follow-up time of 28.1 months (range, 6-90 months) for non-randomised studies and 34.3 months (range, 0.233-120 months) for randomised studies. Pooled incidence rates for clinically relevant major complications included contralateral ACL injury at 6.0%, postoperative meniscal issues at 5.4%, cyclops lesions at 4.8%, graft failure at 4.1%, patellar fracture at 2.2%, hardware removal at 1.7%, infection at 1.5%, and donor-site quadriceps tendon rupture at 0.7%. Pooled incidence rates for clinically relevant minor complications included anterior knee pain at 9.7%, kneeling pain at 9.5%, sensation deficits at 4.4%, loss of extension at 4.2%, donor-site tendinopathy at 3.9%, cosmetic issues at 1.8%, and hematoma at 1.5%.

CONCLUSIONS

QT ACL-R resembles other graft types in its rates and types of postoperative complications. In this exploratory systematic review, no complications of QT ACL-R were found to be disproportionately represented in the literature. This graft type should remain an option with comparable complication rates to other graft choices.

LEVEL OF EVIDENCE

Level IV.

REGISTRATION

This study was preregistered under PROSPERO with preregistration code CRD42022302078.

Global research status of anterior cruciate ligament reconstruction: a bibliometric analysis

Purpose

The aim of this study is to comprehensively analyze the publications of anterior cruciate ligament reconstruction (ACLR) research and display the current research status in this field.

Methods

Articles regarding ACLR research published before October 7, 2021, were downloaded from the Web of Science Core Collection. Excel 2016 and Bibliometric website were used to analyze the annual article trends and international cooperation network. CiteSpace V and VOSviewer were used to perform co-occurrence and citation analyses for journals, institutions, authors, cocitation authors and keywords. Burst keyword detection was also performed with CiteSpace V.

Results

A total of 12 223 ACLR articles were identified. The American Journal of Sports Medicine (1636 publications, 92,310 citations), the Pennsylvania Commonwealth System of Higher Education (624 publications, 25,304 citations) and Freddie H. Fu (321 publications, 15,245 citations) were journals, institutions and authors with the most publications and citations, respectively. Patellar tendon was the keyword with the most occurrences (1618 times) and return to sport was the keyword with the most burst strength (burst strength: 46.99).

Conclusion

ACLR-related publications showed a rapid increasing trend since 1990. A large number of articles have been published by authors from different institutions and countries, some of which have gained great academic influence. Based on keyword analysis, patellar tendon is identified as the research hotspot and return to sport is identified as the current research frontier.

Quadriceps tendon autograft with or without bone block have comparable clinical outcomes, complications and revision rate for ACL reconstruction: a systematic review

PURPOSE

The purpose of this systematic review is to report complications, graft failure, fixation methods, rehabilitation protocol, clinical and patient-reported outcomes, and return to sports with the use of quadriceps tendon graft with the bone block (QT-B) and without bone block (QT-S).

METHODS

According to the PRISMA guidelines a comprehensive search was performed across PubMed/MEDLINE, Scopus, EMBASE, and Cochrane Library databases from inception until April 2022. Only prospective studies using quadriceps tendon autograft with a minimum of 20 patients were considered for inclusion. The outcome measures extracted from the studies were the KT-1000, Lysholm score, Subjective and Objective IKDC, Tegner, Marx Score, complications, failures and/or revision surgery, and rate of return to sports. Cochrane risk of bias and MINORS tool were used for the risk of bias assessment of all included studies.

RESULTS

A total of 13 studies were included, consisting of 5 randomized controlled trials, 6 cohort studies, 1 case-control and 1 case series. A total of 484 patients received QT-S in 6 studies of which 224 (46.2%) were males and 212 (43.8%) females with a mean age of 21.5 ± 7.5 (range 14-58). While 243 patients received QT-B in 7 studies of which 167 (68.7%) were males and 76 (31.3%) females with a mean age of 28.9 ± 4.5 (range: 18-49). The studies analyzed had a mean MINORS score of 14.6 (range, 12-19). Both QT-B and QT-S for ACL reconstruction reported satisfactory results in terms of patient-reported outcome measures. Although, a slightly higher anterior laxity was found with the QT-S than with the QT-B.

CONCLUSION

Quadriceps tendon with a bone block (QT-B) or without bone block (QT-S) for ACL reconstruction is supported by current literature. Both grafts are safe and viable options for ACL reconstruction with comparable clinical outcomes, complications and revision rates.

LEVEL OF EVIDENCE

Level IV.

REGISTRATION

PROSPERO-CRD42022347134; https://www.crd.york.ac.uk/prospero/.

Primary surgery versus primary rehabilitation for treating anterior cruciate ligament injuries: a living systematic review and meta-analysis

OBJECTIVE

Compare the effectiveness of primarily surgical versus primarily rehabilitative management for anterior cruciate ligament (ACL) rupture.

DESIGN

Living systematic review and meta-analysis.

DATA SOURCES

Six databases, six trial registries and prior systematic reviews. Forward and backward citation tracking was employed.

ELIGIBILITY CRITERIA

Randomised controlled trials that compared primary reconstructive surgery and primary rehabilitative treatment with or without optional reconstructive surgery.

DATA SYNTHESIS

Bayesian random effects meta-analysis with empirical priors for the OR and standardised mean difference and 95% credible intervals (CrI), Cochrane RoB2, and the Grading of Recommendations Assessment, Development and Evaluation approach to judge the certainty of evidence.

RESULTS

Of 9514 records, 9 reports of three studies (320 participants in total) were included. No clinically important differences were observed at any follow-up for self-reported knee function (low to very low certainty of evidence). For radiological knee osteoarthritis, we found no effect at very low certainty of evidence in the long term (OR (95% CrI): 1.45 (0.30 to 5.17), two studies). Meniscal damage showed no effect at low certainty of evidence (OR: 0.85 (95% CI 0.45 to 1.62); one study) in the long term. No differences were observed between treatments for any other secondary outcome. Three ongoing randomised controlled trials were identified.

CONCLUSIONS

There is low to very low certainty of evidence that primary rehabilitation with optional surgical reconstruction results in similar outcome measures as early surgical reconstruction for ACL rupture. The findings challenge a historical paradigm that anatomic instability should be addressed with primary surgical stabilisation to provide optimal outcomes.

PROSPERO REGISTRATION NUMBER

CRD42021256537.

Closure of the Quadriceps Tendon Autograft Harvest Site for Anterior Cruciate Ligament Reconstruction: A Systematic Review

BACKGROUND

The quadriceps tendon (QT) autograft is a commonly used and effective graft option for anterior cruciate ligament reconstruction (ACLR). Surgical techniques vary, and there is no current standard of care for management of the QT autograft harvest site.

PURPOSE

To examine the literature on patient-reported outcomes and complications after ACLR with a QT autograft and to further clarify the frequency with which the harvest site is closed and potential biomechanical implications.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed using multiple medical databases. Level 1 to 4 studies on patients undergoing ACLR with a QT autograft were included. There were 2 independent reviewers who analyzed all studies. Study quality was analyzed using the methodological index for non-randomized studies checklist.

RESULTS

Overall, 13 studies with a total of 650 patients were included. The mean patient age for all studies was 31 years (range, 14-59 years) with a mean follow-up of 21.2 months (range, 6-84 months). Of the 13 studies, 12 studies (92%) documented patient sex, comprising 331 female patients (55%) and 274 male patients (45%). There were 8 studies (62%) that reported the use of a bony QT autograft in 273 patients, and 5 studies (38%) reported the use of a soft tissue QT autograft in 377 patients. The graft length harvested was most commonly 7 to 8 cm, while the tendon width harvested was 10 mm. Moreover, 5 studies (38%) did not discuss closure of the harvest site, while 2 studies (15%) only closed the harvest site if a capsular rent was present. The surgical technique for harvest-site closure varied when reported in 7 studies (54%). Good to excellent clinical outcomes were reported in 80% of patients when the harvest site was closed.

CONCLUSION

Based on the results of this study, there is no consensus on whether the QT defect should be closed after harvesting the graft for ACLR. It has been reported that closure of the harvest site is performed if there is a capsular rent present. Several techniques are utilized to close the QT autograft harvest site; however, it is unclear if there is a difference in outcomes based on the technique used. Future studies should further clarify whether there are any biomechanical and clinical advantages to closing the QT autograft harvest site.

Evaluation of anterior cruciate ligament surgical reconstruction through finite element analysis

Anterior cruciate ligament (ACL) tear is one of the most common knee injuries. The ACL reconstruction surgery aims to restore healthy knee function by replacing the injured ligament with a graft. Proper selection of the optimal surgery parameters is a complex task. To this end, we developed an automated modeling framework that accepts subject-specific geometries and produces finite element knee models incorporating different surgical techniques. Initially, we developed a reference model of the intact knee, validated with data provided by the Open Knee(s) project. This helped us evaluate the effectiveness of estimating ligament stiffness directly from MRI. Next, we performed a plethora of “what-if” simulations, comparing responses with the reference model. We found that (a) increasing graft pretension and radius reduces relative knee displacement, (b) the correlation of graft radius and tension should not be neglected, (c) graft fixation angle of 20\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{\circ }$$\end{document}∘ can reduce knee laxity, and (d) single-versus double-bundle techniques demonstrate comparable performance in restraining knee translation. In most cases, these findings confirm reported values from comparative clinical studies. The numerical models are made publicly available, allowing for experimental reuse and lowering the barriers for meta-studies. The modeling approach proposed here can complement orthopedic surgeons in their decision-making.

Current trends in the anterior cruciate ligament part 1: biology and biomechanics

A trend within the orthopedic community is rejection of the belief that "one size fits all." Freddie Fu, among others, strived to individualize the treatment of anterior cruciate ligament (ACL) injuries based on the patient's anatomy. Further, during the last two decades, greater emphasis has been placed on improving the outcomes of ACL reconstruction (ACL-R). Accordingly, anatomic tunnel placement is paramount in preventing graft impingement and restoring knee kinematics. Additionally, identification and management of concomitant knee injuries help to re-establish knee kinematics and prevent lower outcomes and registry studies continue to determine which graft yields the best outcomes. The utilization of registry studies has provided several large-scale epidemiologic studies that have bolstered outcomes data, such as avoiding allografts in pediatric populations and incorporating extra-articular stabilizing procedures in younger athletes to prevent re-rupture. In describing the anatomic and biomechanical understanding of the ACL and the resulting improvements in terms of surgical reconstruction, the purpose of this article is to illustrate how basic science advancements have directly led to improvements in clinical outcomes for ACL-injured patients.Level of evidenceV.

Superior results of return to sport after double-bundle versus single-bundle anterior cruciate ligament reconstruction in young active patients

PURPOSE

To compare return to sport and clinical results in young active patients who underwent anatomic single-bundle (SB) versus double-bundle (DB) anterior cruciate ligament reconstruction (ACLR).

METHODS

Young active patients undergoing SB or DB ACLR from 2017 to 2019 at our institution were retrospectively reviewed. The primary outcome measures were the rate and time to return to sports, with secondary measures including the Lachman test, pivot shift test, Lysholm scores, International Knee Documentation Committee (IKDC) scores and graft rupture.

RESULTS

The study included a total of 90 patients (DB group, 42; SB group, 48), with a mean follow-up of 27.1 ± 6.1 months. Young active patients who underwent DB ACLR had a higher rate of return to pivoting sports than those who underwent SB ACLR (HR = 2.4; 95% confidence interval [CI]: 1.4, 4.1; p = 0.013). The DB group returned to pivoting sports at a mean ± SD of 11.0 ± 2.9 months compared with 12.7 ± 2.7 months in the SB group (p = 0.01). There was one traumatic failure in the SB group and one contralateral ACL rupture in the DB group. There was no significant difference in the rate and time to return to running, Lachman test, pivot-shift test, Lysholm or IKDC scores in either group.

CONCLUSION

Both anatomical SB and DB techniques achieved satisfactory clinical outcomes. DB techniques led to superior performance of return to pivoting sports but nonsignificant differences in time and rate of return to running, passive stability measurement, subjective knee function outcome and graft rupture rate in both groups at the 2-year follow-up. The DB ACLR should be considered a viable option to treat young patients with high activity demands.

LEVEL OF EVIDENCE

III.