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

Safety and Early Return to Sports for Early ACL Reconstruction in Young Athletes: A Retrospective Study

Background and Objectives: Although previous reports have shown that early anterior cruciate ligament (ACL) reconstruction is associated with an increased risk of stiffness, recommendations for delayed surgery are based on outdated literature. The advent of arthroscopic surgery and accelerated rehabilitation protocols warrants a reexamination of the optimal surgical timing. The purpose of this study was to investigate complications during early ACL reconstruction after injury in young athletes. Materials and Methods: A total of 87 patients (27 males and 60 females) were included in this study. Patients who underwent anatomic ACL reconstruction using hamstring autografts were evaluated. Patients under 25 years of age with a Tegner activity score greater than 6 were included and classified into three groups according to the time from injury to surgical treatment: one week from injury to surgery (early group), three to six weeks from injury to surgery (normal group), and three to six months from injury to surgery (delayed group). We evaluated the rates of various complications such as graft rupture, contralateral injury, the need for manipulation for loss of ROM, infection, and fracture around the knee up to 2 years postoperatively. In addition, we investigated postoperative muscle strength, Lysholm score, Tegner activity score, and period of the return to sport from injury. Results: Patients in the delayed group were younger than those in the other groups (p = 0.009). Patients in the early group had a lower range of motion than those in the other groups preoperationly. However, the 1-month postoperative range of motion was comparable between groups. Patients in the early group had greater postoperative Tegner activity scores than those in the other groups. The period of return to sport from injury in the delayed group was longer than in the other groups. There were no statistically significant differences in the postoperative complication rate, muscle strength, or Lysholm score. Conclusions: ACL reconstruction performed 1 week from injury to surgery in young athletic patients indicated the rate of complications were not significantly different among the groups. Early ACL reconstruction with no postoperative complications may be related to early return to sports and a high level of sports.

Double-bundle ACL combined with ALL reconstruction for patients at high risk of ACL failure: clinical and radiological results

BACKGROUND

We investigated whether double-bundle (DB) anterior cruciate ligament (ACL) reconstruction (ACLR) combined with anterolateral ligament reconstruction (ALLR) improved clinical and radiological outcomes in patients at high risk of ACL failure. The primary outcome was graft failure, and secondary outcomes included knee stability and patient-reported outcome measures (PROMs).

PATIENTS AND METHODS

Fifty-two patients who underwent DB ACLR combined with ALLR were included in this retrospective cohort study. Preoperative risk factors, including femorotibial angle (FTA), lateral tibial slope (LTS), medial tibial slope (MTS), and meniscal tears, were assessed using X-ray and magnetic resonance imaging (MRI). The grade of post-operative pivot shift, Lysholm score, and Tegner activity score were used to assess clinical outcomes. The minimum follow up duration was 2 years.

RESULTS

The cohort (mean age, 26.1 ± 9.4 years; 51.9% male) had a mean follow-up duration of 28.9 ± 3.4 months. Preoperatively, 57.8% had lateral meniscus (LM) tears, and 61.0% had a grade 2-3 pivot shift. Postoperatively, no graft failures or revision cases occurred during follow-up. Approximately 90.4% of the patients exhibited a negative pivot shift (p < 0.001), with Lysholm and Tegner activity scores of 92.5 ± 6.1 and 5.1 ± 2.0. The medial meniscus (MM) tear group had a significantly smaller FTA than the intact group (p = 0.043). No significant differences in PROMs were found between the LM tear and intact LM groups or between the high and low MTS or LTS groups (p = n.s.).

CONCLUSION

DB ACLR combined with ALLR had satisfactory clinical outcomes in patients at high risk of ACL failure, with no graft failures observed during a mean follow-up duration of 2.4 years. The technique effectively reduced the postoperative pivot shift, regardless of preoperative risk factors.

STUDY DESIGN

Level IV, retrospective therapeutic case-series.

TRAIL REGISTRATION

ethical approval number, 202300134B0; ethical committee, the Institutional Review Board of Chang Gung Medical Foundation.

Validating the capture rate of revisions by the New Zealand ACL Registry: An analysis of all-cause reoperation following primary ACL reconstruction

PURPOSE

To validate the New Zealand Anterior Cruciate Ligament (ACL) Registry's capture rate of revisions by cross-referencing Registry data with reoperations data recorded by the Accident Compensation Corporation (ACC) and identify risk factors for all-cause reoperation.

METHODS

Primary ACL reconstructions performed between April 2014 and September 2019 were individually matched on a record-by-record basis between the two databases. The ACC database was used to identify patients who underwent a reoperation with manual review of operation notes to identify whether a revision or other procedure was performed. This was combined with the number of revisions separately recorded in the New Zealand ACL Registry, which was used as the denominator value to calculate the Registry's capture rate of revisions. Patient and surgical data recorded in the Registry were analysed to identify independent predictors for all-cause reoperation.

RESULTS

A total of 8046 primary ACL reconstructions were matched between the New Zealand ACL Registry and the ACC databases. The reoperation rate was 8.9% (n = 715) at a mean follow-up of 2.5 years. Meniscal-related procedures were the most common reoperation (n = 299, 3.7%), followed by revision ACL reconstruction (n = 219, 2.7%), arthrofibrosis (n = 185, 2.3%), cartilage (n = 56, 0.7%) and implants (n = 32, 0.4%). The New Zealand ACL Registry captured 96% of revisions. Younger age (hazard ratio [HR] > 1.4, p < 0.001), earlier surgery (HR > 1.3, p = 0.05), concurrent meniscal repair (medial meniscus HR = 1.9, p < 0.001 and lateral meniscus HR = 1.3, p = 0.022) and hamstring tendon autografts (HR = 1.4, p = 0.001) were associated with a higher risk of reoperation.

CONCLUSION

The New Zealand ACL Registry captured 96% of revisions. Risk factors for all-cause reoperation included younger age, earlier surgery, meniscal repair and hamstring tendon autografts.

LEVEL OF EVIDENCE

Level III.

Quadriceps Tendon With Bone Autograft Has Better Stability and Magnetic Resonance Imaging Maturation Than Hamstring Tendon Autograft After Anterior Cruciate Ligament Reconstruction in Patients With Knee Hyperextension

PURPOSE

To compare the clinical outcomes of anterior cruciate ligament (ACL) reconstruction between methods using quadriceps tendon with bone (QTB) and hamstring tendon (HT) in patients with hyperextension of the knee.

METHODS

The medical records of patients with knee hyperextension greater than 8° who underwent arthroscopic ACL reconstruction between October 2010 and October 2020 with follow-up for at least 2 years (median, 3 years; interquartile range [IQR], 2.0-4.6 years) were retrospectively reviewed. Side-to-side difference in anterior translation, pivot-shift test grade, Lysholm score, and graft intensity using the Howell grade on magnetic resonance imaging at final follow-up were compared between the QTB and HT groups.

RESULTS

The HT and QTB groups consisted of 42 patients and 21 patients, respectively. The overall mean age was 21.5 years (range, 14-48 years), and the median Tegner Activity Scale score was 6 (range, 3-9). Postoperatively, the median side-to-side difference in anterior translation was 1.75 mm (IQR, 1-3 mm) in the HT group and 1.0 mm (IQR, 0-1.75 mm) in the QTB group (P = .01). Pivot-shift testing showed grade 0 in 74.7%, grade 1 in 18.7%, and grade 2 in 6.6% of patients in the HT group and grade 0 in 85.7% and grade 1 in 14.3% of those in the QTB group (P = .03). The median postoperative Lysholm score was 99 in both groups. Graft signal intensity showed a significant between-group difference: grade I in 52%, grade II in 36%, and grade III in 12% of patients in the HT group versus grade I in 85.7%, grade II in 9.5%, and grade III in 4.8% of those in the QTB group (P = .03).

CONCLUSIONS

In patients who underwent ACL reconstruction for hyperextension of the knee, QTB yielded better clinical outcomes than HT with respect to anterior stability, rotational stability, and graft signal intensity on median 2-year follow-up magnetic resonance imaging.

LEVEL OF EVIDENCE

Level III, retrospective case-control study.

Prospective study of functional outcomes and return to sports after anterior cruciate ligament reconstruction in the knee

PURPOSE

Individual factors of low rates of return to sport after anterior cruciate ligament (ACL) reconstruction were unclear. We evaluated the impact of various individual factors after ACL reconstruction for return to sport in athletes.

METHODS

A prospective study was performed in 1274 athletes, who had undergone ACL autograft reconstruction. Individual factors survey about return to sport was performed during the second year after surgery. Athlete responses were analyzed with a multivariate logistic model adjusted for baseline patient characteristics and an adjusted Cox model.

RESULTS

Younger age and involvement in higher-level sporting activities were associated with a significantly higher frequency and a significantly shorter time to return to sport (running, training, competition; p = 0.001 to 0.028). Men returned to sport more rapidly than women, for both training (p = 0.007) and competition (p = 0.042). Although there was no difference to return to sport between hamstring (HT) and patellar tendon (PT) autograft. We note that MacFL surgery (Mac Intosh modified with intra- and extra-articular autografts used the tensor fasciae latae muscle) was associated with a higher frequency (p = 0.03) and rapidity (p = 0.025) of return to training than HT. Sports people practicing no weight-bearing sports returned to training (p < 0.001) and competition (p < 0.001) more rapidly than other sports people. By contrast, the practicing pivoting sports with contact started running again sooner (p < 0.001).

CONCLUSION

Younger age, male sex, higher level of sports, sportspeople practicing no weight-bearing sports, and MacFL surgery reduce time to return to sport after ACL reconstruction.

Estimation Failure Risk by 0.5-mm Differences in Autologous Hamstring Graft Diameter in Anterior Cruciate Ligament Reconstruction: A Meta-analysis

BACKGROUND

Because grafts are made in 0.5-mm increments clinically for anterior cruciate ligament (ACL) reconstruction, it is important to clarify how the failure rate decreases as the diameter increases. Moreover, it is important to know whether even a slight increase in the graft diameter decreases the risk of failure.

HYPOTHESIS

The risk of failure decreases significantly with each 0.5-mm increase in hamstring graft diameter.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

The systematic review and meta-analysis have estimated the diameter-specific failure risk for each 0.5-mm increase in ACL reconstruction using autologous hamstring grafts. We searched for studies describing the relationship between graft diameter and failure rate published before December 1, 2021, in leading databases, such as PubMed, EMBASE, Cochrane Library, and Web of Science, according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We included studies using single-bundle autologous hamstring grafts to investigate the relationship between failure rate and graft diameter of 0.5-mm intervals with >1-year follow-up. Then, we calculated the failure risk caused by 0.5-mm differences in autologous hamstring graft diameter. Assuming Poisson distribution for the statistical model, we employed an extended linear mixed-effects model in the meta-analyses.

RESULTS

Five studies containing 19,333 cases were eligible. The meta-analysis revealed that the estimated value of the coefficient of diameter in the Poisson model was -0.2357 with a 95% CI of -0.2743 to -0.1971 (P < .0001). With every 1.0-mm increase in diameter, the failure rate decreased by 0.79 (0.76-0.82) times. In contrast, the failure rate increased by 1.27 (1.22-1.32) times for each 1.0-mm decrease in diameter. The failure rate significantly decreased with each 0.5-mm increase in graft diameter in the range of <7.0 to >9.0 mm from 3.63% to 1.79%.

CONCLUSION

The risk of failure decreased correspondingly with each 0.5-mm increase in graft diameter in the range of <7.0 to >9.0 mm. Failure is multifactorial; however, increasing the graft diameter as much as possible to match each patient's anatomic space without overstuffing is an effective precaution that surgeons can take to reduce failures.

The increased lateral tibial slope may result in inferior long-term clinical outcome after DB-ACL reconstruction

PURPOSE

To determine if there is a correlation between lateral tibial slope and long-term clinical results in patients who underwent double-bundle ACL reconstruction.

METHODS

We retrospectively reviewed patients that received double-bundle ACL reconstruction at a single institution by a single surgeon from January 2011 to December 2014. All the magnetic resonance imaging were reviewed and lateral tibial slopes (LTS) were recorded by an experienced surgeon and rechecked by the other two authors of this study that specialized in orthopedic knee surgery. The relationship between PROMs measurement and lateral tibial slope were analyzed. The patients were then separated into two groups (LTS > 7.4° and < 7.4°) according to the previous study.

RESULTS

A total of 119 patients were enrolled in this study. All enrolled patients were followed for at least 8 years. The PROMS result were negatively correlated with the lateral tibial slope (p values all < 0.001). The patients with high lateral tibial slope had significantly lower PROMS values (Lysholm 94.26 ± 5.61 vs 80.15 ± 8.28, p = 0.013; IKDC 82.99 ± 4.55 vs 70.09 ± 7.15, p = 0.003; Tegner 9.32 ± 0.95 vs 6.85 ± 1.99, p < 0.001). Finally, the LTS cutoff value between patients with "Good" and "Fair" Lysholm score in our study was 7.55 degrees.

CONCLUSIONS

Patients with high lateral tibial slope may result in inferior long-term subjective outcomes. The using of double-bundle ACL reconstruction along cannot overcome the negative impact caused by steep lateral tibial slope. A lateral tibial slope of 7.55° may be used as a cut-off for a good clinical outcome.

LEVEL OF EVIDENCE

III retrospective comparative prognostic trial.

Double and Single Bundle in Athletes: A Comparison in Medium and Long-Term Rates to Return to Sport and Re-Injury

Objectives

Compare, retrospectively, the medium- and long-term of return to sport rates and re-injury of the anterior cruciate ligament (ACL) in patients submitted to single-bundle (SB) compared to double-bundle (DB) technique reconstruction.

Methods

Athletes operated by SB or DB ACL reconstruction, with at least five years of follow-up at a single center, were included. The following data were collected: demographic data; competitive sports practice before the injury; previous surgery; injury/surgery to the contralateral knee; return to sports and level of the return; re-injury (time of the re-injury after the first surgery; mechanism of trauma for the re-injury; necessity of operative treatment); signs and complaints related to the knee the last clinical consultation.

Results

Seventy-six athletes (27 SB and 49 DB) were included. The return to sport rate (98%) was the same for both groups, and the return to the previous level rate showed an improvement in the DB group but without statistical significance (63% vs. 79%; P = 0.173). However, other outcomes showed higher results for the DB group: lower re-injury rate throughout the follow-up period (41% vs. 18%; P = 0.034) and during the first year of follow-up (22% vs. 4%; P = 0.021), and less stiffness (0% vs. 22%, P = 0.001). While in primary reconstruction cases, there was not a higher re-injury rate using SB (P = 0.744), in the revision cases, SB was correlated with more re-injuries than DB (P = 0.002).

Conclusion

The overall re-injury in the medium- and long-term and the return to practice sports at the same level as before surgery in athletes submitted to DB reconstruction were slightly better than those submitted to SB reconstruction, especially in the cases that were asecond time lesion ( revisioned knees).

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.

Single Bundle Anterior Cruciate Ligament With Anterolateral Ligament Reconstruction Yields Similar Clinical and Radiographic Results at Minimum 2-Year Follow-Up Versus Double Bundle Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Controlled Trial

PURPOSE

To compare the clinical, radiographic, and second-look arthroscopic outcomes between double-bundle (DB) anterior cruciate ligament (ACL) reconstruction (DB group) and combined single-bundle (SB) ACL and anterolateral ligament (ALL) reconstruction (SB + ALL group) by a prospective randomized controlled trial.

METHODS

From May 2019 to June 2020, 84 patients were enrolled in this study. Among them, 10 were lost to follow-up. Thirty-six and 38 patients were successfully allocated to the DB (mean follow up 27.3 ± 4.2 months) and SB + ALL groups (27.2 ± 4.5 months), respectively. The preoperative and postoperative Lachman test, pivot shift test, anterior translation on stress radiographs, KT-2000 arthrometer, Lysholm score, International Knee Documentation Committee score, and Tegner activity score were evaluated and compared. Graft continuity was evaluated using postoperative magnetic resonance imaging (MRI) (32 and 36 patients underwent MRI in the DB and SB + ALL groups at 7.4 ± 3.2 and 7.5 ± 2.9 months after surgery, respectively), and second-look examinations (second-look examination and tibial screw removal were performed concomitantly when patients (1) had tibial screw-related irritation or (2) needed the screws removed, 28 and 23 patients underwent examinations in the DB and SB + ALL groups at 24.0 ± 6.8 and 24.9 ± 8.1 months after surgery, respectively). All measurements were compared between the groups.

RESULTS

Postoperative clinical outcomes significantly improved in both groups. (All variables showed P < .001) No statistically different outcomes were found between the 2 groups. Additionally, postoperative graft continuity on MRI and second-look examinations were not different between the 2 groups.

CONCLUSIONS

The DB and SB + ALL groups showed similar postoperative clinical, radiographic, and second-look arthroscopic outcomes. Both groups showed excellent postoperative stability and clinical outcomes compared with the preoperative measurements.

LEVEL OF EVIDENCE

Level II, randomized controlled trial.

One-stage anterior cruciate ligament revision surgery after primary failed double-bundle reconstruction: a systematic review

INTRODUCTION

Anterior cruciate ligament (ACL) revision surgery after failed double-bundle (DB) reconstruction is a challenging procedure. This study aimed to systematically review the research on ACL revision surgery following failed DB reconstruction, providing an overview on indications, surgical techniques, clinical outcomes and potential pitfalls occurring while performing this therapeutic approach.

MATERIALS AND METHODS

Literature published from exception to February 2023 was searched in the Pubmed/MEDLINE, Embase and CINAHL databases. Studies in English reporting on patients who underwent ACL revision surgery after prior failed DB reconstruction were considered. Review articles and expert opinion or editorial pieces were excluded. Outcomes of interest included indications and pre-operative planning, surgical technique and associated procedures, type of revision surgery (either one- or two-stage), graft choice, clinical and functional outcomes, rate of complications, failure rate.

RESULTS

Overall, 4 studies met all the inclusion criteria for this review. All were published between 2007 and 2020. The search resulted in two retrospective comparative studies, one case series, and one case report. Average follow-up periods ranged from 24 to 45 months. From these studies, 66 patients (66 knees) were identified. One-stage revision surgery was performed in 64 on 66 patients (97%) with pathologic laxity following DB ACL reconstruction. Most frequently reported outcome was Lysholm score in five studies: average postoperative Lysholm score ranged from 90.5 to 91.0 while Tegner activity level ranged from 5.6 to 7.0. In 4 patients (6%) re-revision surgery was performed due to graft re-rupture.

CONCLUSIONS

One-stage ACL revision surgery following DB ACL reconstruction appears feasible providing satisfying outcomes and limited complications. The literature on this subject is limited and further comparative studies reporting long-term outcomes are needed, as high-level studies on this topic are still lacking.

Evaluating the Use of PROMs in Paediatric Orthopaedic Registries

Patient-reported outcome measures (PROMs) provide structured information on the patient's health experience and facilitate shared clinical decision-making. Registries that collect PROMs generate essential information about the clinical course and efficacy of interventions. Whilst PROMs are increasingly being used in adult orthopaedic registries, their use in paediatric orthopaedic registries is not well known. The purpose of this systematic review was to identify the frequency and scope of registries that collect PROMs in paediatric orthopaedic patient groups. In July 2023, six databases were systematically searched to identify studies that collected PROMs using a registry amongst patients aged under 18 years with orthopaedic diagnoses. Of 3190 identified articles, 128 unique registries were identified. Three were exclusively paediatric, 27 were majority paediatric, and the remainder included a minority of paediatric patients. One hundred and twenty-eight registries collected 72 different PROMs, and 58% of these PROMs were not validated for a paediatric population. The largest group of orthopaedic registries collected PROMs on knee ligament injuries (21%). There are few reported dedicated orthopaedic registries collecting PROMs in paediatric populations. The majority of PROMs collected amongst paediatric populations by orthopaedic registries are not validated for patients under the age of 18 years. The use of non-validated PROMs by registries greatly impedes their utility and impact. Dedicated orthopaedic registries collecting paediatric-validated PROMs are needed to increase health knowledge, improve decision-making between patients and healthcare providers, and optimise orthopaedic management.

Review of Cha et al. (2005) on "Arthroscopic Double Bundle Anterior Cruciate Ligament Reconstruction: An Anatomical Approach"

This classic discusses the original publication 'Arthroscopic double-bundle anterior cruciate ligament reconstruction (ACL): An anatomical approach', the first detailed description of the surgical technique popularised by Dr Freddie Fu. The technique, in which the anteromedial and posterolateral bundles of the ACL are reconstructed individually using two grafts with independent bone tunnels, was designed to more closely recreate the function of the native ACL by more closely reproducing the functional anatomy. This reconstruction was biomechanically superior to single-bundle reconstruction, particularly with regards to rotational control, leading to great interest from ACL surgeons around the world. Clinical superiority was more difficult to demonstrate; however, and the technical difficulty of the procedure has limited its use. Nevertheless, the pursuit of improved patient outcomes through attention to functional anatomical detail continues. 'Recreating the functional anatomy of the intact ACL remains the cornerstone of ACL reconstruction'.

The incidence of tibial tunnel coalition is higher than femoral tunnel coalition in double-bundle anterior cruciate ligament reconstruction using hamstring autografts: A systematic review

INTRODUCTION

Intra-operative and postoperative coalition of tunnels may occur in double-bundle (DB) anterior cruciate ligament reconstruction (ACLR). However, the incidence and effect on clinical outcomes of tunnel coalition following primary DB ACLR using a hamstring autograft has yet be analyzed, and thus remains unknown. The objective of this systematic review was to identify the incidence of tunnel coalition upon DB ACLR using hamstring autografts and to elucidate any clinical outcomes and/or complications that tunnel coalition may have postoperatively.

HYPOTHESIS

The incidence of tunnel coalition would increase in respect to time from the index surgery, and that tunnel coalition would be related to poorer clinical outcomes compared to non-coalition cases.

METHODS

Three databases (PubMed, EMBASE, Cochrane Library) were searched in accordance with PRISMA and R-AMSTAR guidelines on June 15, 2020. Relevant studies were screened in duplicate and data regarding patient demographics, incidence of femoral and tibial tunnel coalition, and outcomes were extracted. Coalition rate was also compared between follow up at 1 month or less defined as "shorter-term", and 6 months or greater as "longer-term". Coalition is defined as the missing of a bony bridge between the two tunnels.

RESULTS

Thirty-six studies examining 1,574 patients, mean age 29.1 years, were included in this study. 29 studies (1,110 knees) reported the incidence of femoral coalition with a pooled rate of coalition of 8% (95% CI=4-12%). 28 studies (1,129 knees) reported an incidence of tibial coalition with a pooled rate of coalition of 21% (95% CI=13-30%). The incidence of tibial coalition was significantly higher than the incidence of femoral coalition across 21 comparative studies (OR=3.37, 95% CI=1.41-8.09, p=0.0065). Only two studies (111 knees) compared tunnel coalition and non-coalition groups for clinical outcome and no significant differences were observed with regards to Lysholm score, Tegner activity scale, and knee laxity measured with a KT-1000 arthrometer.

DISCUSSION

The rate of tibial tunnel coalition in DB ACLR is higher than femoral tunnel coalition, particularly at longer-term follow-up. Despite the higher radiographic evidence of coalition, the clinical effects of such remain to be ascertained, and further comparative studies are required to facilitate this understanding.

LEVEL OF EVIDENCE

IV, systematic review.

Meniscal resection increases the risk of residual knee laxity even in patients undergoing anatomic double-bundle anterior cruciate ligament reconstruction with eight strands of hamstring autografts

PURPOSE

To compare the midterm clinical outcomes of different meniscal surgeries in patients undergoing anatomic double-bundle anterior cruciate ligament reconstruction (DB-ACLR) with eight strands of hamstring (HT8) autografts and explore the potential predictive risk factors for residual knee laxity.

METHODS

From 2010 to 2017, a total of 410 patients who underwent anatomic trans-tibial DB-ACLR with HT8 autografts (169 patients without meniscal surgery, 105 patients with meniscal repair, and 136 patients with meniscal resection) were included in this study. The equivalent graft diameter was introduced to make the total graft size of DB-ACLR comparable with that of single-bundle ACLR and calculated as the square root of the quadratic sum of the diameter for each bundle. Residual laxity was defined as excessive anterior tibial translation or residual pivot shift at any follow-up visit, while graft rupture was confirmed by second-look arthroscopy or magnetic resonance imaging.

RESULTS

The mean follow-up period was 8.3 ± 2.2 years. The mean equivalent graft diameter was 9.9 ± 0.7 mm. Graft rupture was confirmed in 16 (3.9%) patients, while residual laxity was detected in 72 (17.6%) patients (34 [25.0%] in the meniscal resection group vs. 22 [13.0%] in the no meniscal surgery group, p = 0.021). In the multivariate logistic regression analysis, high-grade preoperative knee laxity (odds ratio OR 2.04, p = 0.020), equivalent graft diameter < 9 mm (OR 3.31 compared with 9-10 mm, p = 0.012; OR 3.28 compared with ≥ 10 mm, p = 0.019), and meniscal resection (OR 1.94 compared with no meniscal surgery, p = 0.045) were associated with residual laxity.

CONCLUSION

During a midterm follow-up, meniscal resection increased the risk of residual knee laxity even in patients undergoing anatomic DB-ACLR with HT8 autografts. Increasing the hamstring graft diameter and preserving the menisci are important strategies for ACLR to restore knee stability.

LEVEL OF EVIDENCE

Level III.

Scoping Review on ACL Surgery and Registry Data

Purpose of Review

To present an overview of registry-based anterior cruciate ligament (ACL) research, as well as provide insight into the future of ACL registries.

Recent Findings

During the past decades, the ACL registries have had an important role in increasing our understanding of patients with ACL injuries and their treatment. The registry data has deepened our understanding of factors that have been associated with an increased risk of sustaining an ACL injury and for evaluation of treatment factors and their impact on patient-related outcomes. Recently, registry-based ACL research using artificial intelligence (AI) and machine learning (ML) has shown potential to create clinical decision-making tools and analyzing outcomes. Thus, standardization of collected data between the registries is needed to facilitate the further collaboration between registries and to facilitate the interpretation of results and subsequently improve the possibilities for implementation of AI and ML in the registry-based research.

Summary

Several studies have been based on the current ACL registries providing an insight into the epidemiology of ACL injuries as well as outcomes following ACL reconstruction. However, the current ACL registries are facing future challenges, and thus, new methods and techniques are needed to ensure further good quality and clinical applicability of study findings based on ACL registry data.

Double-Bundle Versus Single-Bundle Anterior Cruciate Ligament Reconstruction in Patients With Significant Passive Anterior Tibial Subluxation

BACKGROUND

Passive anterior tibial subluxation (PATS) is often observed in patients with anterior cruciate ligament tears. Postoperative outcomes of double-bundle (DB) and single-bundle (SB) anterior cruciate ligament reconstruction (ACLR) with significant PATS (>6 mm) are unclear.

HYPOTHESIS

DB-ACLR could achieve better stability and clinical outcomes than SB-ACLR in patients with PATS >6 mm.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Retrospective analysis was peformed on 626 consecutive patients who underwent primary anatomic ACLR between October 2016 and November 2017. Anterior subluxation of the lateral and medial compartments in extension relative to the femoral condyles was measured on preoperative magnetic resonance imaging scans. Among patients who demonstrated significant PATS (>6 mm) in the lateral compartment, 54 who underwent DB-ACLR (study group) were matched to 54 who underwent SB-ACLR (control group). PATS, stability (pivot-shift test and KT-2000 arthrometer), the Lysholm score, and the International Knee Documentation Committee (IKDC) grade were investigated preoperatively and at 3- to 4-year follow-up.

RESULTS

The preoperative mean PATS values in the lateral and medial compartments were not significantly different between groups (control vs study: lateral compartment, 8.1 ± 1.8 vs 8.5 ± 2.1 mm; medial compartment, 5.2 ± 1.9 vs 5.4 ± 1.9 mm; P > .05). Postoperatively, mean PATS values in the lateral and medial compartments of the study group were significantly improved as compared with the control group (control vs study: lateral compartment, 5.9 ± 2.8 vs 3.2 ± 4.1 mm; medial compartment, 3.7 ± 2.9 vs 1.4 ± 2.3 mm; P < .05). Significantly superior results were found for knee stability in the study group regarding the Lachman test (grade 0/1/2/3, study vs control: 29/22/3/0 vs 16/28/10/0; P = .031), pivot-shift test (grade 0/1/2/3, study vs control: 44/9/1/0 vs 30/19/5/0; P = .023), and KT-2000 arthrometer (study vs control: 2.5 ± 1.5 vs 3.9 ± 1.4 mm; P < .001). Clinical scores showed significantly better results in the study group in terms of IKDC score (study vs control: 87.9 ± 8.7 vs 81.2 ± 15.0; P = .01), Tegner activity score (study vs control: 6.0 ± 1.4 vs 4.9 ± 1.5; P < .001), and Lysholm score (study vs control: 91.7 ± 7.0 vs 86.3 ± 11.4; P = .004).

CONCLUSION

DB-ACLR achieved better knee stability and clinical outcomes when compared with SB-ACLR in patients with PATS >6 mm at 3- to 4-year follow-up.

Return to Sport and Re-Injury Rate after Double-Bundle Anterior Cruciate Ligament Reconstruction with at least Five Years of Follow-Up

BACKGROUND

This study retrospectively evaluated the medium- and long-term results of patients submitted to double-bundle (DB) anterior cruciate ligament (ACL) reconstruction.

METHODS

A retrospective study of case series at a single center. Cases submitted to isolated ACL reconstruction with at least five years of follow-up were included. The following data were collected: demographic data; practice of competitive sport before the injury; previous surgery; injury/surgery in the contralateral knee; return to the practices of sports and level; re-injury (postoperative time; mechanism; need for surgery); and symptoms at the last clinical follow-up visit. Descriptive and sub-group analyses were performed.

RESULTS

Sixty-nine patients were included; 52 men (75%), 49 athletes (71%), 47 (68%) with primary injury, mean age of 30 years (SD 10). The patients were followed up for an average of 8.7 years (minimum 5, maximum 11.8) after surgery. After the reconstruction, 67 (97%) returned to the sport; 75% at the same level as before the injury. Ten patients (14%) suffered re-injury after an average of 32 months (between 9 and 50 months). Regarding the outcome of re-injury, no statistically significant differences were found between subgroups of athletes vs non-athletes or primary injury vs revision surgery, despite a significant tendency towards increased re-injury levels in athletes. However, this tendency was not statistically significant.

CONCLUSION

In our series of patients operated on with the double-bundle technique and with a long follow-up time, 14% presented re-injury, with no differences between primary and revision cases, and with a trend towards higher re-injury levels among the athletes in relation to the non-athletes. The rate of return to sport was satisfactory, with 97%, of which 75% were playing at the same level as before the injury.

Double-bundle anterior cruciate ligament reconstruction technique has advantages in chondroprotection and knee laxity control compared with single-bundle technique : A long-term follow-up with a minimum of 12 years

PURPOSE

To compare the long-term clinical outcomes of single-bundle anterior cruciate ligament reconstruction (SBR) and double-bundle anterior cruciate ligament reconstruction (DBR) in patients with isolated anterior cruciate ligament (ACL) rupture, presenting no meniscus injury and no obvious preoperative cartilage degeneration.

METHODS

One hundred and three patients (38.6 ± 9.5 years) with a median follow-up of 151.6 months (range, 144-189 months) completed the retrospective study (SBR group: n = 51; DBR group: n = 52). Clinical outcomes were evaluated with physical examinations, KT-2000 anterior and posterior stability measurement with the knee in 30º of flexion, International Knee Documentation Committee (IKDC) subjective score, Tegner score, Lysholm score; magnetic resonance imaging (MRI) (3.0 T) was performed, and International Cartilage Repair Society (ICRS) cartilage degeneration grades were determined. Multivariate analysis was performed to identify factors associated with cartilage degeneration.

RESULTS

There were significant differences in the pre- and postoperative IKDC, Lysholm and Tegner scores between the SBR and DBR groups. The SBR group had over double the rate of positive pressure/rub patellar test results (SBR vs DBR, 43.1% vs. 19.2%, p < 0.011). The KT-2000, pivot-shift and Lachman test results were stratified and analyzed, and significant differences between the SBR and DBR groups were found (p < 0.05, respectively). The distribution of ICRS grades differed significantly between the groups at the last follow-up (p = 0.013). A multivariate analysis found that age and operation procedures were significant predictors of 0 and non-0 ICRS grades (odds ratio, 6.077 [95% CI 2.117-17.447] and 0.210 [95% CI 0.068-0.654], respectively) (p < 0.05).

CONCLUSION

Both SBR and DBR achieved overall good long-term results. DBR had advantages in objective outcome measures and was superior in preventing the occurrence of cartilage degeneration. Age was identified as a preoperative risk factor for significant postoperative cartilage degeneration.

LEVEL OF EVIDENCE

III. ClinicalTrials.gov: NCT03984474.

Press-fit fixation in anterior cruciate ligament reconstruction yields low graft failure and revision rates: a systematic review and meta-analysis

PURPOSE

Press-fit fixation is a hardware-free technique in anterior cruciate ligament reconstruction (ACLR). The purpose of this review was to quantitatively assess the risk profile and outcomes of press-fit fixation and provide an update on its effectiveness compared to more standard fixation techniques of ACLR.

METHODS

The electronic databases PUBMED, MEDLINE, and EMBASE were searched on March 26, 2020 for therapeutic randomized controlled trials (RCT) addressing press-fit fixation for primary ACLR. The Grading of Recommendations Assessment, Development and Evaluation tool was used to assess the quality for randomized studies. A meta-analysis with a random-effects model was used to pool applicable outcomes data.

RESULTS

A total of six eligible RCTs were included in this review. There were 292 patients (72.9% male) with a mean age of 28.8 ± 3.8 years and a mean follow-up of 81.3 ± 88.3 months that underwent press-fit ACLR on the femoral, tibial or both tunnels. Femoral fixation techniques included press-fit fixation (96.6%) and cross-pin fixation (3.4%). Tibial fixation techniques included press-fit (37.0%), staples (28.1%), interference screws (21.2%) and abarticular post-screws (13.7%). Graft options included bone-patellar tend--bone autografts (73.6%) and semitendinosus and gracilis tendon autograft (26.4%). Significant improvements (p < 0.05) from baseline to follow-up were found for clinical outcomes. Significantly less postoperative bone tunnel enlargement (p < 0.05) was found with tibial press-fit fixation when compared to biodegradable screws. The overall complication rate was 13.3%. There were no significant differences in complication rates [odds ratio = 0.84 (95%CI 0.43-1.66); p = n.s.] (I² = 0%) between patients undergoing femoral press-fit fixation and femoral metal interference screw fixation.

CONCLUSION

The overall graft failure and revision rates with press-fit ACLR were low. There were no significant differences in complication rates between patients undergoing femoral press-fit and femoral metal interference screw fixation. Included studies found that patients undergoing press-fit fixation for ACLR had significant improvements in functional outcome scores postoperatively and had significantly reduced postoperative bone tunnel enlargement compared to patients undergoing bioabsorbable fixation. Thus, early evidence suggests that press-fit fixation appears to be a good option for patients undergoing ACLR.

LEVEL OF EVIDENCE

I.

A Systematic Review of Risk Factors for Anterior Cruciate Ligament Reconstruction Failure

Although most studies have introduced risk factors related to anterior cruciate ligament reconstruction failure, studies on combinations of high-risk factors are rare. To provide a systematic review of the risk factors of anterior cruciate ligament reconstruction failure to guide surgeons through the decision-making process, an extensive literature search was performed of the Medline, Embase and Cochrane Library databases. Studies published between January 1, 2009, and September 19, 2019, regarding the existing evidence for risk factors of anterior cruciate ligament reconstruction failure or graft failure were included in this review. Study quality was evaluated with the quality index. Ultimately, 66 articles met our criteria. There were 46 cases classified as technical factors, 21 cases as patient-related risk factors, and 14 cases as status of the knee joint. Quality assessment scores ranged from 14 to 24. This systematic review provides a comprehensive summary of the risk factors for anterior cruciate ligament reconstruction failure, including technical factors, patient-related factors, and the factors associated with the status of the knee joint. Emphasis should be placed on avoiding these high-risk combinations or correcting modifiable risk factors during preoperative planning to reduce the rate of graft rupture and anterior cruciate ligament reconstruction failure.

A Retrospective Comparison of Single-Bundle Anterior Cruciate Ligament Reconstruction With Lateral Extra-Articular Tenodesis With Double-Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE

To compare postoperative objective knee stability and clinical outcomes between double-bundle (DB) anterior cruciate ligament reconstruction (ACLR) and single-bundle (SB) ACLR combined with lateral extra-articular tenodesis (LET).

METHODS

ACL-injured patients with grade 3 pivot-shift who underwent either DB ACLR (DB ACLR group) or SB ACLR with LET (SB ACLR+LET group) were enrolled. All patients who met inclusion and exclusion criteria were retrospectively evaluated for knee laxity (the anterior translation and pivot-shift grade), clinical outcomes using the International Knee Documentation Committee (IKDC) examination form, Kellgren-Lawrence grade, graft maturation score on second-look arthroscopy, and revision rates at the last follow-up.

RESULTS

From an initial cohort of 171 consecutive patients over a 3-year period, 95 (56%) met inclusion and exclusion criteria. The SB ACLR+LET group (n = 47) showed significantly better results in pivot-shift grade at the last follow-up as compared with the DB ACLR group (n = 48) (P = .021). In the SB ACLR+LET group, 93.6% (44/47) were grade 0, whereas 72.9% (35/48) in the DB ACLR group were grade 0. The SB ACLR+LET group (grade A: 42, grade B: 4 and grade C: 1) showed significantly superior results in IKDC objective grade compared with the DB ACLR group (grade A: 32; grade B: 8; and grade C: 8) (P = .017). However, no statistically significant difference could be shown in anterior translation, subjective functional IKDC score, or revision rate between the 2 groups. The mean follow-up duration was 49.7 ± 5.7 months.

CONCLUSIONS

SB ACLR + LET demonstrated fewer pivot-shifts (P = .021) and superior IKDC objective grades (P = .017) than a DB ACLR at a mean follow-up of almost 50 months.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Degree of Anterolateral Ligament Injury Impacts Outcomes After Double-Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE

To evaluate the effect of anterolateral ligament (ALL) injury identified on preoperative magnetic resonance imaging (MRI) on postoperative outcomes after double-bundle (DB) anterior cruciate ligament reconstruction (ACLR).

METHODS

For this retrospective study, the inclusion criteria were patients who were at least 3 years out of DB ACLR. Exclusion criteria included a delay in MRI over 4 weeks, delay in surgery over 6 months, single-bundle ACLR, and revision surgery. Enrolled patients were divided into 2 groups according to the ALL injury grade in preoperative MRI by a musculoskeletal radiologist who was blinded to the perioperative findings (the high-grade group with complete or nearly complete tear: n = 53 and the low-grade group with intact ALL or partial tear: n = 33). Knee laxity, clinical outcomes using the International Knee Documentation Committee (IKDC) examination form, and revision rates were compared at the last follow-up (8.1 ± 2.2 years). An independent t test was applied to compare continuous variables, and χ² or Fisher exact test was used to compare the nominal variables.

RESULTS

The anterior translation was 3.2 ± 1.9 mm in the high-grade group and 1.6 ± 1.0 mm in the low-grade group (P < .001). The high-grade group showed 18 cases with a pivot-shift grade of 2 or 3 (40.0%); however, the low-grade group showed only 1 case with a pivot-shift grade 2 or 3 (3.0%) (P = .002). The high-grade group also showed inferior outcomes in the IKDC objective grade (grade A: 49.0%; grade B: 17.0%; grade C: 30.2%; grade D: 3.8% vs grade A: 90.9%; grade B: 6.1%; grade C: 3.0%; grade D: 0%, P = .001) and IKDC subjective score (87.5 ± 9.9 vs 93.9 ± 5.3, P < .001). In addition, the high-grade group showed a greater revision rate (11.3% vs 0%, P = .045).

CONCLUSIONS

DB ACLR for patients with high-grade ALL injury resulted in increased knee laxity, worse clinical outcomes, and higher revision rate compared to patients with low-grade ALL injury.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

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.

No difference in revision rates between anteromedial portal and transtibial drilling of the femoral graft tunnel in primary anterior cruciate ligament reconstruction: early results from the New Zealand ACL Registry

PURPOSE

The use of an accessory anteromedial portal to drill the femoral graft tunnel in primary anterior cruciate ligament (ACL) reconstruction was introduced in the 2000s in an effort to achieve a more anatomic femoral tunnel position. However, some early studies reported an increase in revision ACL reconstruction compared to the traditional transtibial technique. The aim of this study was to analyse recent data recorded by the New Zealand ACL Registry to compare outcomes of ACL reconstruction performed using the anteromedial portal and transtibial techniques.

METHODS

Analysis was performed on primary isolated single-bundle ACL reconstructions recorded between 2014 and 2018 by the New Zealand ACL Registry. Patients were categorised into two groups according to whether an anteromedial portal or transtibial technique was used to drill the femoral graft tunnel. The primary outcome was revision ACL reconstruction and was compared between both groups through univariate and multivariate survival analyses. The secondary outcomes that were analysed included subscales of the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Marx activity score.

RESULTS

Six thousand one hundred and eighty-eight primary single-bundle ACL reconstructions were performed using either the anteromedial portal or transtibial drilling techniques. The mean time of follow-up was 23.3 (SD ± 14.0) months. Similar patient characteristics such as mean age (29 years, SD ± 11), sex (males = 58% versus 57%) and time to surgery (median 4 months, IQR 5) were observed between both groups. The rate of revision ACL reconstruction was 2.6% in the anteromedial portal group and 2.2% in the transtibial group (n.s.). The adjusted risk of revision ACL reconstruction was 1.07 (95% CI 0.62-1.84, n.s.). Patients in the anteromedial portal group reported improved scores for subscales of the KOOS and higher Marx activity scores at 1-year post-reconstruction.

CONCLUSION

There was no difference in the risk of revision ACL reconstruction between the two femoral tunnel drilling techniques at short-term follow-up. We observed minor differences in patient-reported outcomes at 1-year follow-up favouring the anteromedial portal technique, which may not be clinically relevant. Surgeons can achieve good clinical outcomes with either drilling technique.

LEVEL OF EVIDENCE

III.

A retrospective study to compare the clinical effects of individualized anatomic single- and double-bundle anterior cruciate ligament reconstruction surgery

To evaluate the clinical efficacy of single- and double- bundle individualized anatomic anterior cruciate ligament (ACL) reconstruction, we retrospectively analyzed the data and charts of 920 patients with ACL rupture who received individualized anatomic ACL reconstruction surgery at our center. All of the patients underwent arthroscopic ACL reconstruction with autologous hamstring tendons. The patients were divided into two groups: the single-bundle individualized anatomic reconstruction group (N = 539), and the double-bundle individualized anatomic reconstruction group (N = 381). The IKDC, Lysholm and Tegner scores were used to subjectively evaluate the function of the knee joint during the postoperative follow-up. The Lachman test, pivot shift test and KT-3000 were used to objectively evaluate the stability of the knee. All 920 patients participated in clinical follow-up (average duration: 27.91 ± 3.61 months) achieved satisfied outcomes with few complications. The postoperative IKDC, Lysholm and Tegner scores, and the objective evaluation of knee joint stability were significantly improved compared to the preoperative status in both groups (P < 0.05). No statistically significant difference was observed between the two groups at the final follow-up (P > 0.05). Therefore, no difference in terms of the IKDC, Lysholm and Tegner score, or KT-3000 was observed between the individualized anatomic single- and double-bundle ACL reconstruction techniques. Both techniques can be used to restore the stability and functionality of the knee joint with satisfactory short-term efficacy.

Quadriceps tendon anterior cruciate ligament reconstruction

Quadriceps tendon is a promising alternative graft option for anterior cruciate ligament (ACL) reconstruction, which can be harvested with or without a bone block as well as a full or partial thickness graft. Therefore, quadriceps tendon graft could be used in primary and revision ACL reconstruction based on the requirements (tunnel size, tunnel position, etc.). The all soft tissue, partial thickness quadriceps tendon graft in detail and pitfalls of the harvest are described in the present review. After quadriceps tendon harvest, especially in soccer players, who need a strong quadriceps to strike a ball with power, the postoperative rehabilitation may need to be adapted. LEVEL OF EVIDENCE: V.

Smaller cross-sectional areas of the hamstring tendon measured from preoperative ultrasonography are likely to need additional gracilis harvesting for double-bundle anterior cruciate ligament reconstructions

BACKGROUND/PURPOSE

Hamstring tendon autografts are commonly used for double-bundle anterior cruciate ligament reconstruction (DB-ACLR). If the volume of the semitendinosus (ST) tendon is insufficient, the gracilis (G) tendon is also harvested. Additional harvesting of the G autograft can affect patients' short-term postoperative outcome, such as muscle recovery; thus, preoperative information about whether an additional G autograft is needed would be useful. The purpose of this study was to investigate whether preoperative measurement of the ST tendon using ultrasonography could inform the intraoperative decision to harvest the G tendon.

METHODS

We enrolled 20 patients (13 men and seven women) who underwent DB-ACLR between October 2017 and March 2019. The mean patient age was 28.5 years. The ipsilateral ST tendon was measured using ultrasonography before surgery. Measurements included the diameter and breadth of the short-axis image. The cross-sectional area (CSA) was calculated from these measurements. During surgery, when two grafts with diameters of ≥ 5.0 mm could not be made, the G tendon was also harvested. Patients were categorized into two groups: the ST group where only the ST tendon was harvested, and the semitendinosus gracilis tendon (STG) group where the ST and G tendons were both harvested. The CSA value was compared between the two groups, and the cutoff value was calculated.

RESULTS

In the ST group (n = 8), the mean diameter and breadth of the semitendinosus tendon were 4.21 and 2.34 mm, respectively. In the STG group (n = 12), the mean diameter and breadth of the ST tendon were 3.39 and 1.78 mm, respectively. The CSAs calculated for the ST group and the STG group were 7.74 mm² and 4.79 mm², respectively. A cutoff value of 7.0 mm² was found to correspond to a specificity and sensitivity to harvest the G tendon of 87.5% and 75.0%, respectively.

CONCLUSIONS

The preoperative CSA of the ST tendon determined using ultrasonography can, therefore, be informative for deciding whether to harvest the G tendon for DB-ACLR. The results of this study provide valuable information for graft selection in anterior cruciate ligament reconstruction.

LEVEL OF EVIDENCE

IV (Retrospective case series design).

Rates of revision and surgeon-reported graft rupture following ACL reconstruction: early results from the New Zealand ACL Registry

PURPOSE

There remains a lack of consensus on the patient factors associated with graft rupture following anterior cruciate ligament (ACL) reconstruction. This study aimed to identify the rate of revision and surgeon-reported graft rupture and clarify the patient risk factors for failure.

METHODS

Analysis was conducted on prospective data captured by the New Zealand ACL registry. All primary isolated ACL reconstructions recorded between April 2014 and December 2018 were reviewed to identify the rate of revision and surgeon-reported graft rupture. Univariate and multivariate survival analysis was performed to identify patient factors associated with revision and graft rupture.

RESULTS

A total of 7402 primary isolated ACL reconstructions were reviewed and had a mean follow-up time of 23.1 (SD ± 13.9) months. There were 258 surgeon-reported graft ruptures (3.5%) of which 175 patients underwent subsequent revision ACL reconstruction (2.4%). Patients younger than 18 years had the highest risk of revision (adjusted HR = 7.29, p < 0.001) and graft rupture (adjusted HR = 4.26, p < 0.001) when compared to patients aged over 36 years. Male patients had a higher risk of revision (adjusted HR = 2.00, p < 0.001) and graft rupture (adjusted HR = 1.70, p < 0.001) when compared to their female counterparts. Patients who underwent ACL reconstruction within 6 months of their injury had a two times increased risk of revision compared to patients who had surgery after 12 months (adjusted HR = 2.15, p = 0.016).

CONCLUSION

Younger age, male sex and a shorter injury-to-surgery time interval increased the risk of revision, while younger age and male sex increased the risk of surgeon-reported graft rupture.

LEVEL OF EVIDENCE

II.

Lateral Extra-articular Tenodesis in Anterior Cruciate Ligament Reconstruction

A subset of patients have residual rotational laxity following anterior cruciate ligament reconstruction (ACLR) despite the evolution of ACLR techniques. In recent years, there has been increased interest in addressing residual laxity because it is associated with poor outcomes after ACLR. There is an expanding body of knowledge on the anatomy and biomechanics of the anterolateral soft tissue restraints in regard to their rotational control of the knee and this has reignited an interest in extra-articular reconstruction techniques for augmenting ACLR. Reconstruction techniques currently used can be broadly categorized as either lateral extra-articular tenodesis or anterolateral ligament reconstruction. In this review, we discuss the relevant anatomy, biomechanics, and rationale behind the indications and technique of our current extra-articular augmentation procedure.

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.

Factors associated with revision following anterior cruciate ligament reconstruction: A systematic review of registry data

BACKGROUND

To identify the patient and surgical factors associated with revision anterior cruciate ligament (ACL) reconstruction as reported by all national and community ACL registries.

METHODS

A systematic review was performed on the MEDLINE, Embase and Cochrane Library databases. Eligibility criteria included English studies published by national or community ACL registries reporting on primary ACL reconstruction and risk factors associated with revision ACL reconstruction.

RESULTS

Thirty-three studies from the Swedish, Norwegian, Danish and Kaiser Permanente registries were included for review. Fourteen studies from all four registries reported younger age as a risk factor for revision ACL reconstruction. In addition, the Swedish registry reported concomitant medial collateral ligament (MCL) injury, undergoing earlier surgery, lower Knee Injury and Osteoarthritis Outcome Score (KOOS), smaller graft diameter and an anteromedial portal drilling technique as risk factors for revision. The risk factors reported by the Norwegian registry included lower body mass index (BMI), lower KOOS, hamstring tendon grafts and suspensory fixation. The Danish registry reported hamstring tendon grafts, anteromedial portal drilling and suspensory fixation as risk factors. The Kaiser Permanente registry reported male sex, lower BMI, ethnicity, hamstring tendon grafts, allografts, smaller graft diameter and an anteromedial portal technique as risk factors for revision.

CONCLUSION

Multiple patient and surgical factors were associated with increased risk of revision ACL reconstruction in registries. Younger age and the use of hamstring tendon grafts were consistently reported as risk factors for failure.

Revision Anterior Cruciate Ligament Reconstruction After Primary Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction: A Case Series of 40 Patients

PURPOSE

To evaluate the surgical methods according to the status of tunnels at the time of revision anterior cruciate ligament reconstruction (ACLR) and to evaluate clinical outcomes of revision ACLR in patients who underwent primary ACLR with the anatomic 4-tunnel double-bundle (DB) technique.

METHODS

A total of 487 patients who underwent primary anatomic DB ACLR from April 2010 to July 2016 were retrospectively reviewed, and among those knees, the patients who underwent revision ACLR were included in the study. The patients with concomitant posterior cruciate ligament injuries were excluded. Forty patients (40 knees) were identified and enrolled. The surgical methods were reviewed. The range of motion, objective laxity using KT-2000, Lysholm score, Hospital for Special Surgery score, International Knee Documentation Committee subjective score, and Tegner score after revision ACLR were compared with those after primary ACLR in the same patient using paired t-test with Bonferroni correction.

RESULTS

The timing of reinjury after primary ACLR and mean interval between primary and revision ACLR were 18 months (range 1.5-80 months) and 24 months (range 4-82 months), respectively. Among 40 patients, 38 patients (95%) underwent 1-stage revision with the DB technique using pre-existing tunnels without compromised positioning of the grafts, and the other 2 patients (5%) underwent 2-stage revision. The postrevision range of motion, KT-2000, Lysholm score, Hospital for Special Surgery score, International Knee Documentation Committee subjective score, and Tegner score were 137 ± 7°, 2.4 ± 1.2 mm, 91.4 ± 5.8, 98.9 ± 2.2, 78.6 ± 11.5, and 5.5 ± 1.2, respectively, and did not show any differences from those after primary ACLR.

CONCLUSIONS

In the revision setting after primary anatomic DB ACLR, most of the cases could be managed with 1-stage revision with DB technique using pre-existing tunnels, and the objective laxity and clinical scores after revision DB ACLR were comparable with those after primary DB ACLR.

LEVEL OF EVIDENCE

Case series, Level IV.

Strength in numbers? The fragility index of studies from the Scandinavian knee ligament registries

PURPOSE

The fragility index (FI) is a metric to evaluate the robustness of statistically significant results. It describes the number of patients who would need to change from a non-event to an event to change a result from significant to non-significant. This systematic survey aimed to evaluate the feasibility of applying the FI to findings related to anterior cruciate ligament (ACL) reconstruction in the Scandinavian knee ligament registries.

METHODS

The PubMed, EMBASE, Cochrane Library and AMED databases were searched. Studies from the Scandinavian knee ligament registers were eligible if they reported a statistically significant result (p < 0.05) for any of the following dichotomous outcomes; ACL revision, contralateral ACL reconstruction or the presence of postoperative knee laxity. Only studies with a two-arm comparative analysis were included. Eligibility assessment, data extraction and quality assessment were performed by two independent reviewers. The dichotomous analyses were stratified according to the grouping variable for the two comparative arms as follows; age, patient sex, activity at injury, graft choice, drilling technique, graft fixation, single- versus double-bundle, concomitant cartilage injury and country. The two-sided Fisher's exact test was used to calculate the FI of all statistically significant analyses.

RESULTS

From 158 identified studies, 13 studies were included. They reported statistical significance for a total of 56 dichotomous analyses, of which all but two had been determined by a time-to-event analysis. The median sample size for the arms was 5540 (range 92-38,666). The mean FI for all 56 dichotomous analyses was 80.6 (median 34.5), which means that a mean of 80.6 patients were needed to change outcome status to generate a non-significant result instead of a significant one. Seventeen analyses (30.4%) immediately became non-significant when performing the two-sided Fisher's exact test and, therefore, had an FI of 0. The analyses related to age were the most robust, with a mean FI of 178.5 (median 116, range 1-1089). The mean FI of the other grouping variables ranged from 0.5 to 48.0.

CONCLUSION

There was large variability in the FI in analyses from the Scandinavian knee ligament registries and almost one third of the analyses had an FI of zero. The FI is a rough measurement of robustness when applied to registry studies, however, future studies are needed to determine the most appropriate metric for robustness in registry studies. The use of the FI can provide clinicians with a deeper understanding of significant study results and promotes an evidence-based approach in the clinical care of patients.

LEVEL OF EVIDENCE

Systematic review of prospective cohort studies, Level II.

Failure risks in anatomic single-bundle anterior cruciate ligament reconstruction via the outside-in tunnel technique using a hamstring autograft

Purpose

To retrospectively evaluate the failure risk factors in anatomic single-bundle anterior cruciate ligament (ACL) reconstruction via outside-in tunnel technique using a hamstring autograft, and investigate the relationship between each risk factor.

Methods

The patients who underwent the ACL reconstruction with a minimum 1-year follow-up were included. We divided the patients into two groups - those who experienced graft failure (the failure group) and those who did not experience graft failure (the no failure group) - and compared their age, height, weight, sports activity level, graft size, and muscle strength. We defined graft failure as patients who underwent revision ACL reconstruction or had a second injurious ACL episode and those with a graft grade of C or D based on the International Knee Documentation Committee score.

Results

The study included 232 patients (101 male, 131 female; mean age at operation was 26.1 ± 11.9 years). The failure rate was 11.6% (failure group: 27 patients; no failure group: 205 patients). The patients in the failure group were younger and had higher sports activity level than those in the no failure group. (p < 0.001 and p < 0.001, respectively). Patient body weight in the failure group was lower than that in the no failure group (p = 0.047). Regarding the graft size of the tibial side, the failure group had smaller graft sizes than the no failure group (p = 0.030). With respect to muscle strength, quadriceps strength 6 months after surgery in the failure group was stronger than that in the no failure group (p = 0.001). In addition, the hamstring/quadriceps strength (H/Q) ratios 3 and 6 months after surgery were lower in the failure group than that in the no failure group (p = 0.041 and p = 0.001, respectively). There was an association between the age and the body weight, between the body weight and the graft size of the tibial side, and between lower age and high sports activity. Moreover, the high quadriceps strength at 6 months and the low H/Q ratio at 3 months were related to the low H/Q ratio at 6 months.

Conclusion

Young age, high activity sports level, low body weight, small graft diameter of the tibial side, high quadriceps strength at 6 months, and low H/Q ratio at 3 and 6 months can be failure risk factors in anatomic single-bundle ACL reconstruction via the outside-in tunnel technique using a hamstring autograft.

Anterior cruciate ligament reconstruction with concomitant meniscal surgery: a systematic review and meta-analysis of outcomes

PURPOSE

The aim of this review was to compare the clinical outcomes of anterior cruciate ligament reconstruction (ACLR) with either meniscal repair or meniscectomy for concomitant meniscal injury. The primary hypothesis was that short-term clinical outcomes (≤ 2-year follow-up) for ACLR concomitant with either meniscal repair or resection would be similar. The secondary hypothesis was that ACLR with meniscal repair would result in better longer term outcomes compared with meniscal resection.

METHODS

The authors searched two online databases (EMBASE and MEDLINE) from inception until March 2018 for the literature on ACLR and concurrent meniscal surgery. Two reviewers systematically screened studies in duplicate, independently, and based on a priori criteria. Quality assessment was also performed in duplicate. The Knee injury and Osteoarthritis Outcome Score (KOOS) sub-scale scores at 2 years post-operatively were combined in a meta-analysis of proportions using a random-effects model.

RESULTS

Of 2566 initial studies, 25 studies satisfied full-text inclusion criteria. Mean follow-up was 2.09 years, with a total sample of 37,087 subjects including controls. The meta-analysis demonstrated equivocal results at 2 years, except for KOOS symptom scores which favoured meniscal resection over repair. Mean KT-1000 side-to-side difference (SSD) scores were 1.51 ± 0.60 mm for meniscal repair, 1.96 ± 0.36 mm for meniscal resection, and 1.58 ± 0.20 for control patients (isolated ACLR). Medial meniscal repair showed decreased anterior knee joint laxity compared to medial meniscal resection (P < 0.001). Patients with meniscal repair had higher rates of re-operation (13.3% vs 0.8% for meniscal resection, P < 0.001).

CONCLUSION

Patients with ACLR combined with meniscal resection demonstrate better symptoms at 2-year follow-up compared to patients with ACLR combined with meniscal repair. ACLR combined with meniscal repair results in decreased anterior knee joint laxity with evidence of improved patient-reported outcomes in the long term, but also higher re-operation rates.

LEVEL OF EVIDENCE

III.

Double bundle anterior cruciate ligament reconstruction: Failure rate and patients-reported outcomes at 4-11 years of follow up

Background

Biomechanical studies have demonstrated that single bundle (SB) anterior cruciate ligament (ACL) reconstruction (SB-ACLr), which represents the gold standard for the management of ACL lesions, is not sufficient to completely restore the rotational stability and resistance to valgus stress of the knee.

Purpose

To evaluate the failure rate and patients reported outcomes at a long-term follow-up of double bundle anterior cruciate ligament reconstruction (DB-ACLr).

Study design

Retrospective cohort study.

Materials and methods

The database of arthroscopic DB-ACLr procedures performed from 2006 to 2015 at our Institution was retrospectively reviewed. Patients were screened for eligibility according to the following inclusion criteria: magnetic resonance imaging (MRI) evidence of anterior cruciate ligament (ACL) lesion, positive anterior drawer test and/or Lachman test; age ≤ 45 years at the time of surgery; DB-ACLr with autologous hamstrings, minimum follow up of 24 months. Patients were excluded if they presented associated lesions of the knee preoperatively or at the time of surgery, expect for meniscal lesions, or in case of inability to complete clinical questionnaires. Clinical outcomes were assessed at a mean follow up of 95.4 ± 21.9 months (range 51-129 months; median 98 months) using the Tegner-Lysholm score and the IKDC subjective score. Failures were defined as Tegner-Lysholm score ≤65 points, and were confirmed with MRI.

Results

58 (81.7%) male and 13 (18.3%) female patients (mean age 29.7 ± 7.8 years) were included in the study. 2 (2.8%, 95% CI 0.3-9.8%) patients had a failure of DB-ACLr both occurred after a sports trauma. The IKDC subjective score was statically better in patients younger than 30 years. Tegner-Lysholm and IKDC subjective score were statistically better in professional athletes and in patients with isolated medial or lateral meniscus lesion instead of combined medial and lateral meniscus lesion.

Conclusion

DB-ACLr technique provides excellent clinical results at a long term follow-up. Low failure rate and high percentage of return to sports participation at the same pre-injury level was found in our cohort of patients.

Over-the-top ACL reconstruction yields comparable outcomes to traditional ACL reconstruction in primary and revision settings: a systematic review

PURPOSE

To assess clinical outcomes of over-the-top (OTT) ACL reconstruction (ACLR) in skeletally mature patients, where physeal sparing is not a consideration. The hypothesis is that OTT will produce successful yet inferior outcomes compared to anatomic ACL approaches in both primary and revision settings.

METHODS

Two reviewers searched two online databases (EMBASE and MEDLINE) from inception to October 2017 for literature on OTT ACLR in skeletally mature patients. The systematic screening process was completed in duplicate, independently, and based on predetermined criteria. An expert in the field was consulted to resolve disagreements for full-text screening. Quality assessment of included papers was performed independently and in duplicate.

RESULTS

From 3148 initial studies, 16 eligible studies (three RCTs and 13 case series) satisfied inclusion criteria. Three focused on the revision setting. The mean age of patients undergoing primary reconstruction was 26.9 ± 3.6, with 21.3% female patients and 31.4 ± 1.2 (26.1% female) in revision settings. Of primary studies reporting return to sport (n = 151), 69% of patients returned to pre-injury sports participation, with a total 94% returning to any sports activity. In revision settings (n = 48), 52.1% of patients returned to pre-injury sports participation, 25.2% returned to a lower level and 12.5% ceased sporting activity. Primary reconstruction studies reported a mean post-operative Tegner score of 6.5 ± 0.5 (n = 181) and mean KOOS of 82.8 ± 8.1 (n = 96). Primary studies reported a total 13 graft failures (3.7%), seven of which were re-ruptures (2.0%). The revision failure rate was 8.4% (four patients).

CONCLUSION

Clinically important outcomes for OTT ACLR are comparable to literature figures for traditional all-inside, transtibial and/or anteromedial portal drilling techniques. This holds true in revision settings.

LEVEL OF EVIDENCE

IV.

Tunnel osteolysis post-ACL reconstruction: a systematic review examining select diagnostic modalities, treatment options and rehabilitation protocols

PURPOSE

The purpose of this systematic review was to (1) identify the optimal diagnostic modality for tunnel widening in skeletally mature patients; (2) identify potentially modifiable risk factors for tunnel widening, such as graft type, and (3) determine what elements of a post-operative rehabilitation program exert the most influence on TW.

METHODS

The electronic databases MEDLINE, EMBASE, PubMed, and Cochrane Library were searched from database inception to January 2018. Studies that discussed tunnel widening following anterior cruciate ligament reconstruction (ACLR) of skeletally mature patients and written in English were included. Descriptive statistics, such as means, ranges, and measures of variance (e.g. standard deviations, 95% confidence intervals (CI)) are presented where applicable.

RESULTS

103 studies (6,383 patients) were included. Plain radiographs were the most commonly used diagnostic modality, but radiographs on average required 10 months longer than CT and 2 months longer on average than MRI to diagnose tunnel widening after ACLR. Although CT was the least commonly used modality, it was the shortest time to diagnose tunnel widening at 9.5 months after ACLR. Bone-patellar tendon-bone (BPTB) allograft had the largest average tunnel widening overall. BPTB autograft had the lowest average tunnel widening overall. Double-bundle hamstring graft configuration had a lower average tunnel widening than single-bundle configuration. Rehabilitation protocols after ACLR that used a full weight-bearing prescription in rehabilitation showed a greater average femoral tunnel widening than partial weight-bearing, and partial weight-bearing showed a greater average tibial tunnel widening than full weight-bearing.

CONCLUSIONS

Based on this systematic review and the descriptive data evaluated, CT demonstrated a time of 9.5 months on average from ACLR to diagnosing tunnel osteolysis post-ACLR. With respect to graft types, double-bundle hamstring autografts reported lower average femoral and tibial TW than single-bundle hamstring autografts. BPTB autografts reported the lowest average TW and BPTB allograft the largest average TW of all the grafts. Furthermore, extension-locked bracing had the lowest TW of all the brace protocols. Lastly, several other surgical technical parameters influencing tunnel osteolysis remain to be determined. No definitive recommendations can be made at this time due to the high heterogeneity of data and the lack of comparative studies analysed in this systematic review.

LEVEL OF EVIDENCE

IV.

Graft failure is more frequent after hamstring than patellar tendon autograft

PURPOSE

The risk of graft failure after anterior cruciate ligament (ACL) reconstructions with hamstring or patellar tendon was evaluated in a French population of athletes.

METHODS

Athletes who had undergone ACL autograft reconstruction and who received rehabilitation care at the European Center for Sports Rehabilitation (CERS; Capbreton, France) were screened for this prospective cohort study. Eligibility criteria included a simple hamstring autograft or patellar tendon autograft surgical technique. Patients were contacted by phone to participate in follow-up during the second year after surgery. The primary endpoint was the graft failure frequency, evaluated with a multivariate logistic model with adjustment for baseline patient characteristics. The secondary endpoint was time to graft failure, analyzed by an adjusted Cox model.

RESULTS

A total of 2424 athletes were included after having a hamstring autograft (semitendinosus and gracilis) or a patellar tendon autograft between 2011 and 2014. Of the 988 athletes who responded to a follow-up phone call (40.7% response rate), 33 were excluded for new contralateral ACL rupture (3.3%), with 955 included for analysis (713 hamstring autografts; 242 patellar-tendon autografts). There were no significant differences between the baseline characteristics of the patients analyzed and the population which did not respond to the questionnaire. A significant difference in the frequency of graft failure was seen, 6.5% for hamstring autografts vs 2.1% for patellar-tendon autografts [adjusted odds ratio (OR) = 3.64, 95% CI (1.55; 10.67); p = 0.007]. Mean time to graft failure was 10.7 vs 17.4 months for hamstring and patellar-tendon autografts respectively [adjusted hazard ratio (HR) = 3.50, 95% CI (1.53; 10.11); p = 0.008]. Age less than 25 years significantly increased the frequency of graft failure [adjusted OR = 3.85 (1.89; 8.72); p < 0.001]. The rate of patients returning to competitive sport after the first graft was not significantly different for the two techniques: 70.8% for hamstring and 77.8% for patellar tendon [adjusted OR = 0.718; 95% CI (0.50; 1.02)].

CONCLUSIONS

Graft failure is significantly more frequent after hamstring than patellar tendon autografts in a French population, despite similar rates of return to competition. Athletes aged less than 25 years have a higher risk of failure than those aged ≥ 25 years. Our results are in accordance with recent Scandinavian studies.

LEVEL OF EVIDENCE

II.

Single-Bundle Versus Double-Bundle Anterior Cruciate Ligament Reconstruction-5-Year Results

PURPOSE

To compare anatomic single-bundle (SB) with double-bundle (DB) anterior cruciate ligament reconstruction (ACL-R) and to evaluate the respective clinical outcome results.

METHODS

In a prospective randomized study, 64 patients were included and separated into 2 groups. Anatomic SB and DB ACL-Rs were performed with hamstring tendons. Five years after surgery, the follow-up (FU) examination comprised International Knee Documentation Committee (IKDC) 2000, Laxitester (ORTEMA Sport Protection, Markgroeningen, Germany) measurement, and radiograph evaluation. Power calculation was performed to achieve a 95% confidence interval and 80% power on the base of 7-point IKDC subjective difference between the groups.

RESULTS

A total of 53 patients (83% FU) were examined at 63.2 ± 4.7 months after surgery: 28 patients in the DB group and 25 patients in the SB group. IKDC subjective (SB: 92.8 ± 6.2, DB: 91.6 ± 7.1; P = .55) and objective scores (grade A SB/DB 20%/25%, B SB/DB 72%/57%, C SB/DB 8%/18%, D SB/DB 4%/0%; P = .45) showed no differences comparing both groups. The Laxitester measurements showed no significant difference in regard to anterior-posterior translation in neutral, internal, and external rotation or to rotation angles (P = .79). No difference was seen between the groups regarding osteoarthritic changes and tunnel widening.

CONCLUSIONS

At the 5-year FU, no advantage for either the DB or SB technique in ACL-R can be seen with regard to patient-related and objective outcome measures.

LEVEL OF EVIDENCE

Level I, prospective randomized controlled clinical trial.

No Difference in the KOOS Quality of Life Subscore Between Anatomic Double-Bundle and Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction of the Knee: A Prospective Randomized Controlled Trial With 2 Years' Follow-up

BACKGROUND

The double-bundle reconstruction technique was developed to resemble the properties of the native anterior cruciate ligament (ACL) more closely than the conventional single-bundle technique. The clinical benefit of the operative procedure is controversial, and there is a need for studies with a focus on patient-reported outcomes (PROs).

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

HYPOTHESIS

Anatomic double-bundle ACL reconstruction would be superior to anatomic single-bundle reconstruction regarding the change in the Knee injury and Osteoarthritis Outcome Score (KOOS) Quality of Life (QoL) subscore from baseline to 2-year follow-up.

METHODS

According to sample size calculations, 120 patients aged 18 to 40 years with a primary ACL injury of their knee were randomized to the anatomic double-bundle or anatomic single-bundle reconstruction groups. Patients with posterior cruciate ligament, posterolateral corner, or lateral collateral ligament injuries or with established osteoarthritis were excluded. Patients with residual laxity from a coexistent medial collateral ligament injury were excluded. Data were registered at baseline, 1 year, and 2 years. In 24 patients, postoperative 3-dimensional computed tomography was performed to verify the positioning of the bundles. The outcome measures were the change in KOOS subscores and the International Knee Documentation Committee 2000 subjective score, pivot-shift test result, Lachman test finding, KT-1000 arthrometer measurement, activity level, return-to-sports rate, and osteoarthritic changes on radiographs. A linear mixed model was used for the analysis of all the PROs, including the primary outcome.

RESULTS

The change in the KOOS QoL subscore from baseline to 2-year follow-up was not different between the double- and single-bundle groups (mean change, 29.2 points vs 28.7 points, respectively; -0.5-point difference; 95% CI, -8.4 to 7.4 points; P = .91). Neither were there any differences between the 2 groups in the remaining PROs, knee laxity measurements, or activity levels of the patients. Radiological signs of osteoarthritis were found in 2 patients. Eleven patients had a graft rupture: 8 in the single-bundle group and 3 in the double-bundle group ( P = .16). Three-dimensional computed tomography of the knees verified the positioning of the anteromedial bundle, posterolateral bundle, and single-bundle grafts to be within acceptable limits.

CONCLUSION

There was no difference in the KOOS QoL subscore, the remaining PROs, knee laxity measurements, or activity levels comparing the double- and single-bundle ACL reconstruction techniques. The number of bundles does not seem to influence clinical and subjective outcomes, as long as the tunnels are adequately positioned. Registration: NCT01033188 ( ClinicalTrials.gov identifier).

Factors associated with additional anterior cruciate ligament reconstruction and register comparison: a systematic review on the Scandinavian knee ligament registers

Objective

To present an overview of the Scandinavian knee ligament registers with regard to factors associated with additional ACL reconstruction, and studies comparing the Scandinavian registers with other knee ligament registers.

Design

Systematic review.

Data sources

Four electronic databases: PubMed, EMBASE, the Cochrane Library and AMED were searched, and 157 studies were identified. Two reviewers independently screened titles, abstracts and full-text studies for eligibility. A modified version of the Downs and Black checklist was applied for quality appraisal.

Eligibility criteria for selecting studies

Eligible studies were those published since the establishment of the Scandinavian registers in 2004, which reported factors associated with additional ACL reconstruction and compared data from other registers.

Results

Thirty-one studies met the inclusion criteria and generally displayed good reporting quality. Adolescent age (<20 years) was the most common factor associated with additional ACL reconstruction. The choice of hamstring tendon graft compared with patella tendon, transportal femoral tunnel drilling, smaller graft diameter and utilisation of suspensory fixation devices were associated with additional ACL reconstruction. Concomitant cartilage injury decreased the likelihood of additional ACL reconstruction. Patient sex alone did not influence the likelihood. The demographics of patients undergoing ACL reconstruction in the Scandinavian registers are comparable to registers in other geographical settings. However, there are differences in surgical factors including the presence of intra-articular pathology and graft choice.

Summary

The studies published from the Scandinavian registers in general have a high reporting quality when regarded as cohort studies. Several factors are associated with undergoing additional ACL reconstruction. The results from the registers may help facilitate treatment decisions.

An In Vivo Prediction of Anisometry and Strain in Anterior Cruciate Ligament Reconstruction - A Combined Magnetic Resonance and Dual Fluoroscopic Imaging Analysis

PURPOSE

To evaluate the in vivo anisometry and strain of theoretical anterior cruciate ligament (ACL) grafts in the healthy knee using various socket locations on both the femur and tibia.

METHODS

Eighteen healthy knees were imaged using magnetic resonance imaging and dual fluoroscopic imaging techniques during a step-up and sit-to-stand motion. The anisometry of the medial aspect of the lateral femoral condyle was mapped using 144 theoretical socket positions connected to an anteromedial, central, and posterolateral attachment site on the tibia. The 3-dimensional wrapping paths of each theoretical graft were measured. Comparisons were made between the anatomic, over the top (OTT), and most-isometric (isometric) femoral socket locations, as well as between tibial insertions.

RESULTS

The area of least anisometry was found in the proximal-distal direction just posterior to the intercondylar notch. The most isometric attachment site was found midway on the Blumensaat line with approximately 2% and 6% strain during the step-up and sit-to-stand motion, respectively. Posterior femoral attachments resulted in decreased graft lengths with increasing flexion angles, whereas anterodistal attachments yielded increased lengths with increasing flexion angles. The anisometry of the anatomic, OTT and isometric grafts varied between tibial insertions (P < .001). The anatomic graft was significantly more anisometric than the OTT and isometric graft at deeper flexion angles (P < .001).

CONCLUSIONS

An area of least anisometry was found in the proximal-distal direction just posterior to the intercondylar notch. ACL reconstruction at the isometric and OTT location resulted in nonanatomic graft behavior, which could overconstrain the knee at deeper flexion angles. Tibial location significantly affected graft strains for the anatomic, OTT, and isometric socket location. CLINICAL RELEVANCE: This study improves the knowledge on ACL anisometry and strain and helps surgeons to better understand the consequences of socket positioning during intra-articular ACL reconstruction.