A prospective comparison of 3 hamstring ACL fixation devices--Rigidfix, BioScrew, and Intrafix--randomized into 4 groups with 2 years of follow-up

What's in a Name? Defining 'Failure' in Anterior Cruciate Ligament Reconstruction Randomized Controlled Trials: A Systematic Review

PURPOSE OF REVIEW

Graft failure, one of the most common outcomes in anterior cruciate ligament reconstruction randomized controlled trials, lacks a consensus definition. The purpose of this study was to systematically summarize current practice and parameters in defining anterior cruciate ligament reconstruction graft 'failure'.

RECENT FINDINGS

Forty studies (4466 participants) satisfied the inclusion criteria. Of these, 90% either defined failure formally or referenced the etiology of failure, the remaining 10% used the term failure without referencing the anterior cruciate ligament reconstruction graft. Among the included studies, there was a high level of inconsistency between the definitions of graft failure. The extracted data was categorized into broader groups, revealing abnormal knee laxity (80%) and graft re-rupture (37.5%) as the most common parameters incorporated in the definitions of graft failure in high-level randomized controlled trials. This review shows that anterior cruciate ligament reconstruction randomized controlled trials lack a consistent definition for graft failure. A universal definition is vital for clarity in medical practice and research, ideally incorporating both objective (e.g. graft re-rupture) and subjective (e.g. validated questionnaires) parameters. A composite outcome should be established which includes some of the common parameters highlighted in this review. In the future, this review can be used to assist orthopaedic surgeons to establish a formal definition of anterior cruciate ligament reconstruction graft 'failure'.

Early ACLR and Risk and Timing of Secondary Meniscal Injury Compared With Delayed ACLR or Nonoperative Treatment: A Time-to-Event Analysis Using Machine Learning

BACKGROUND

Surgical and nonoperative management of anterior cruciate ligament (ACL) injuries seek to mitigate the risk of knee instability and secondary meniscal injury. However, the associated risk and timing of secondary meniscal tears have not been completely elucidated.

PURPOSE

To compare risk and timing of secondary meniscal injury between patients receiving nonoperative management, delayed ACL reconstruction (ACLR), and early ACLR using a machine learning survival analysis.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A geographic database was used to identify and review records of patients with a diagnosis of ACL rupture between 1990 and 2016 with minimum 2-year follow-up. Patients undergoing ACLR were matched 1:1 with nonoperatively treated controls. Rate and time to secondary meniscal tear were compared using random survival forest algorithms; independent models were developed and internally validated for predicting injury-free duration in both cohorts. Performance was measured using out-of-bag c-statistic, calibration, and Brier score. Model interpretability was enhanced using global variable importance and partial dependence curves.

RESULTS

The study included 1369 patients who underwent ACLR and 294 patients who had nonoperative treatment. After matching, no significant differences in rates of secondary meniscal tear were found (P = .09); subgroup analysis revealed the shortest periods of meniscal survival in patients undergoing delayed ACLR. The random survival forest algorithm achieved excellent predictive performance for the ACLR cohort, with an out-of-bag c-statistic of 0.80 and a Brier score of 0.11. Significant variables for risk of meniscal tear for the ACLR cohort included time to return to sports or activity ≤350 days, time to surgery ≥50 days, age at injury ≤40 years, and high-impact or rotational landing sports, whereas those in the nonoperative cohort model included time to RTS ≤200 days, visual analog scale pain score >3 at consultation, hypermobility, and noncontact sports.

CONCLUSION

Delayed ACLR demonstrated the greatest long-term risk of meniscal injury compared with nonoperative treatment or early ACLR. Risk factors for decreased meniscal survival after ACLR included increased time to surgery, shorter time to return to sports or activity, older age at injury, and involvement in high-impact or rotational landing sports. Pending careful external validation, these models may be deployed in the clinical space to provide real-time insights and enhance decision making.

Femoral fixation methods for hamstring graft in anterior cruciate ligament reconstruction: A network meta-analysis of controlled clinical trials

Objective

To compare the clinical effectiveness of cortical button (CB), cross-pin (CP) and compression with interference screws (IS) fixation techniques in anterior cruciate ligament (ACL) reconstruction using hamstring graft.

Methods

Studies were systematically retrieved from PubMed, Embase, Cochrane Library and Web of Science up to May 20, 2021. Primary outcomes were KT-1000 assessment, International Knee Documentation Committee (IKDC) score A or B, Lachman’s test, pivot-shift test, visual analogue scale (VAS) score, Lysholm score, Tegner score, and Cincinnati Knee Score. Secondary outcomes included reconstruction failures and synovitis. League tables, rank probabilities and forest plots were drawn for efficacy comparison.

Results

Twenty-six controlled clinical trials (CCTs) with 1,824 patients undergoing ACL reconstruction with hamstring graft were included. No significant differences were found among CB, CP and IS fixation methods regarding the 10 outcomes. For KT-1000 assessment, IKDC score A or B, Lachman’s test, VAS score and pivot-shift test, CP had the greatest probability of becoming the best method, and IS may be the suboptimal method in 4 out of these 5 outcomes except pivot-shift test.

Conclusions

CP, CB and IS fixations have comparable clinical performance, while CP fixation is most likely to be the optimum fixation technique for hamstring graft in ACL reconstruction. Future larger-sample studies of high quality comparing these techniques in more clinical outcomes are required.

A prospective comparison of 3 hamstring ACL fixation devices-rigidfix, bioscrew, and intrafix-randomized into 4 groups with a minimum follow-up of 5 years

Background

ACL (anterior cruciate ligament) reconstruction remains the gold standard surgical option for patients with ACL tears. There are many fixation devices available for ACL reconstruction. Recent ACL reconstruction strategies are aiming to reproduce the native anatomy and normal kinematics of the knee. This is a five years follow-up report of some of the new devices for graft fixation. A two years follow-up data was published previously.

Methods

120 patients were randomized into four different groups (30 each) for ACL reconstruction with hamstring tendons: group I femoral Rigidfix cross-pin and Intrafix tibial extension sheath with a tapered expansion screw; group II Rigidfix femoral and BioScrew interference screw tibial fixation; group III BioScrew femoral and Intrafix tibial fixation; group IV BioScrew fixation into both tunnels. The evaluation methods were clinical examination, knee scores, and instrumented laxity measurements.

Results

In this 5 years follow-up there were 102/120 (85%) patients available, but only 77 (64,2%) attended the clinical examinations. No significant difference between the groups in the clinical results was detected. Between the 2 and 5 years follow-up there were 6 additional procedures in group I and one in group II. There was a significant difference in additional procedures between group I and the other groups (P = .041).

Conclusion

There was a statistically significant difference in the additional procedures, most in group I (six). The ACL grafts were intact. Other statistically or clinically significant differences in the 5 years follow-up results were not found.

Study design

Randomized controlled clinical trial; Level of evidence, 1.

Trial registration ISRCTN registry with study ID ISRCTN34011837. Retrospectively registered 17.4.2020.

Biomechanical Comparison of a Novel Tibial Fixation Technique Versus Interference Screw Fixation for ACL Reconstruction Using Soft Tissue Grafts

Background:

Controversy remains regarding the optimal technique for tibial fixation of soft tissue grafts in anterior cruciate ligament (ACL) reconstruction.

Purpose/Hypothesis:

To compare the biomechanical outcomes of a novel transtibial tubercle fixation technique with those of a commonly utilized interference screw fixation at the tibial site. Our hypothesis was that transtibial tubercle fixation achieves higher ultimate failure loads than interference screw fixation.

Study Design:

Controlled laboratory study.

Methods:

We used 24 matched porcine tibias and digital extensor tendons, from which 12 grafts and tibial tunnels were prepared using the novel transtibial tubercle fixation technique and 12 were prepared using the interference screw fixation technique. The specimens underwent a cyclic loading test (50-250 N applied for 1000 cycles at a frequency of 1 Hz), followed by a load-to-failure test. The slippage, stiffness, and ultimate failure loads were compared between the techniques.

Results:

No differences in slippage were found during the cyclic loading test, and no graft fixation or tibial complex failures occurred during cyclic testing in either group. The transtibial tubercle fixation technique had higher ultimate failure loads (mean ± SD, 756.28 ± 123.43 N) as compared with interference screw fixation (602.15 ± 81.62 N; P < .05). The grafts in the transtibial tubercle fixation group were less stiff than those in the interference screw fixation group (84.43 vs 101.23 N/mm; P < .05).

Conclusion:

Transtibial tubercle fixation achieved higher ultimate failure loads than interference screw fixation in the load-to-failure test.

Clinical Relevance:

The novel transtibial tubercle fixation technique compared favorably with interference screw fixation during ACL reconstruction. This technique does not require hardware, has a low cost, theoretically eliminates the risk of complications associated with hardware implantation (eg, graft damage and pain attributed to retained hardware requiring removal), and is relatively easy to perform.

Biomechanical evaluation of bovine stifles stabilized with an innovative braided superelastic nitinol prosthesis after transection of the cranial cruciate ligament

OBJECTIVE

To determine the stability bovine stifles stabilized with nylon or nitinol superelastic prostheses after transection of the cranial cruciate ligament (CCL).

STUDY DESIGN

Ex vivo study.

SAMPLE POPULATION

Stifles (n = 15) harvested from adult bovine cadavers.

METHODS

The stifles were randomly assigned pairwise to a ligament reconstruction technique (n = 5): (1) and (2) Hamilton's technique using a prosthesis made of 24 nitinol strands (0.39 mm) braided at 40°or single 600-lb test nylon implant, and (3) nitinol prosthesis placed in femoral and tibial bone tunnels (bone-to-bone). Craniocaudal tibial translation at ±2000 N was applied to the tibia, and mediolateral angular displacement via measured under torsional tibial loading at ±60 Nm on three occasions: intact CCL, transected, and stabilized. Outcomes were evaluated with a mixed effect linear model for repeated measures.

RESULTS

Bone-to-bone using nitinol was the only repair that decreased tibial translation after CCL transection (p = .001) with a 23% change magnitude compared with intact CCL. Hamilton was the only stabilization reestablishing angular displacement, similar to intact CCL (p = .109 and .134 for nitinol and nylon). Bone-to-bone nitinol stabilization decreased angular displacement after CCL-transection with an 8% change magnitude (p = .040) without returning to normal values.

CONCLUSION

CCL replacement with nylon did restore joint stability. Nitinol prostheses passed through single femoral and tibial bone tunnels (bone-to-bone) were the only techniques reducing tibial translation.

CLINICAL SIGNIFICANCE/IMPACT

Bone-to-bone stabilization with a nitinol prosthesis may be considered as an alternative to nylon for CCL replacement in cattle. These results provide evidence to justify clinical evaluation in cattle undergoing CCL replacement.

A comprehensive scoping review of tibial cysts after anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to perform a scoping review of published literature reporting on surgical management of tibial cysts which developed after ACLR.

METHODS

A scoping review was conducted following the Arksey and O'Malley framework for scoping studies and Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) extension for scoping reviews (PRISMA-ScR) guidelines. A search strategy using the terms ["Tibial Cyst" AND "ACL"], ["Pretibial Cyst" AND "ACL"] was applied to the PUBMED database.

RESULTS

Thirty-seven studies published between 1990 and 2019 were a part of this scoping review. Non-absorbable implants for tibial graft fixation were used in 10 studies (comprising a total 21 patients), while bio-absorbable implants were used in 27 studies (comprising a total 115 patients). Incidence of tibial cyst was reported in 3 studies (434 primary ACLRs) from whom 3.9% (n = 17) developed tibial cyst. Tibial cyst development in relation to use of bio-absorbable screws for tibial ACL graft fixation was reported in 16 studies (42.1%). Use of bio-absorbable screws with another factor was found to be related to tibial cyst development in another 1 study (2.6%). Most common symptoms were presence of mass or swelling, pain, tenderness, drainage, instability and effusion.

CONCLUSION

This scoping review demonstrated that tibial cysts is more frequently related to bioabsorbable screws, however it can also occur due to other causes. Current literature on tibial cyst after ACLR is of low-quality evidence. Future research is required to better understand aetiology, risk factors for cyst formation and the best possible mode of management.

LEVEL OF EVIDENCE

IV.

Interference screws are more likely to perform better than cortical button and cross-pin fixation for hamstring autograft in ACL reconstruction: a Bayesian network meta-analysis

PURPOSE

Anterior cruciate ligament (ACL) reconstruction is widely accepted as the first choice of treatment for ACL injury, but there is disagreement in the literature regarding the optimal femoral fixation method. This meta-analysis assesses the evidence surrounding three common femoral fixation methods: cortical button (CB), cross-pin (CP) and interference screws (IS).

METHODS

A systematic search was conducted in Medline, EMBASE and the Cochrane Library to identify studies with evidence level I or II that compared at least two femoral fixation methods with hamstring autograft for ACL reconstruction. Ten primary outcomes were collected. Risk of bias was assessed following the Cochrane Handbook for Systematic Reviews of Interventions. Standardized mean differences (SMD) were estimated using random-effects network meta-analysis in a Bayesian framework. Probability of ranking best (ProBest) and surface under the cumulative ranking curve (SUCRA) were used to rank all treatments. Funnel plots were used to identify publication bias and small-study effects.

RESULTS

Sixteen clinical trials were included for analysis out of 2536 retrieved studies. Bayesian network meta-analysis showed no significant differences among the three fixation methods for the ten primary outcome measures. Based on the 10 outcome measures, the IS, CB and CP had the highest ProBest in 5, 5 and 0 outcomes, and the highest SUCRA values in 5, 4 and 1 outcomes, respectively. No substantial inconsistency between direct and indirect evidence, or publication bias was detected in the outcomes.

CONCLUSION

There were no statistical differences in performance among the CP, CB and IS femoral fixation methods with hamstring autograft in ACL reconstruction, although the IS was more likely to perform better than CB and CP based on the analysis of outcome measures from the included studies.

LEVEL OF EVIDENCE

1.

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.

All-Epiphyseal Physeal-Sparing Anterior Cruciate Ligament Reconstructive Surgery: A Study of 3-Dimensional Modeling to Characterize a Safe and Reproducible Surgical Approach

Purpose

The purpose of this study was to use 3-dimensional magnetic resonance imaging modeling of the skeletally immature knee to help characterize safe and reproducible tunnel positions, diameters, lengths, trajectories, and distances from anatomic landmarks and the physeal and articular cartilage for physeal-sparing anterior cruciate ligament (ACL) reconstructive surgery.

Methods

Magnetic resonance imaging from 19 skeletally immature knees with normal anatomy were gathered. The 3-dimensional models were created, and the relevant anatomic structures were identified. Cylinders simulating tunnel length, diameter and trajectory were superimposed onto the models, and descriptive measurements were performed.

Results

A safe position for the creation of an 8 mm diameter femoral tunnel was described in the lateral femoral condyle. The femoral tunnel length averaged 25.5 ± 2.6 mm. The bony entry point was located 3.8 ± 2.4 mm proximally and 12.7 ± 2.2 mm posteriorly to the lateral epicondyle. The shortest distance from the tunnel edge to the physis and femoral articular cartilage was 2.8 ± 0.7 mm and 3.7 ± 0.9 mm, respectively. The safe position for an 8 mm diameter tibial tunnel was also identified and described in the proximal tibia. The epiphyseal tibial tunnel length from the ACL footprint to the physis averaged 15.5 ± 1.6 mm. The proximal tibial epiphysis was found to accommodate a tibial crosspin measuring 63.5 ± 5.9 mm in length and 8.2 ± 1.5 mm in diameter without disrupting the physis or articular cartilage.

Conclusions

Three-dimensional modeling created from magnetic resonance imaging can help define important anatomic relationships for physeal-sparing ACL reconstructive surgery in skeletally immature knees and may assist in reducing the risk of injury to local anatomic structures.

Clinical Relevance

Knowledge of the anatomic relationships in skeletally immature knees serves as a valuable reference for surgeons performing physeal-sparing ACL reconstruction surgery.

Intra-articular replacement of a ruptured cranial cruciate ligament using the Mini-TightRope in the dog: a preliminary study

BACKGROUND

The TightRope System is a device developed to provide extracapsular stabilization of the cranial cruciate ligament (CCL) rupture in canine stifles. I was then also employed for the extra-articular treatment of shoulder instability and for the intra-articular treatment of hip luxation in dogs and cats.

OBJECTIVES

To evaluate the feasibility of the Mini-TightRope (mTR) System for the intra-articular treatment of CCL rupture in small breed dogs.

METHODS

A cadaveric canine model was used to record the steps of the surgical procedure. Five client owned dogs weighing from 8 to 10 kg and from 2 to 12 years of age were enrolled in the prospective study in which the mTR device was implanted in the stifle joint to replace the ruptured CCL. The dogs were graded using the Bologna Healing Stifle Injury Index (BHSII) and radiographic osteoarthritis (OA) scores.

RESULTS

The outcomes obtained at the time of the surgery (T0) and for the following 12 months (T12) showed an improvement in the functional parameters (BHSII from a median of 74.3 [range, 58.1-82.4] at T0 to 95.6 [range, 94.1-99.3] at T12]). The OA did not change in 3 dogs and increased by only 1 point in 2 dogs.

CONCLUSIONS

In this preliminary study, the mTR was a successful and repeatable intra-articular surgical procedure for all dogs. Additional studies related to the clinical application of the technique in medium-large dogs should be encouraged.

ACL reconstruction using a quadruple semitendinosus graft with cortical fixations gives suitable isokinetic and clinical outcomes after 2 years

PURPOSE

The objective of this single-center randomized single-blinded trial was to assess the hypothesis that anterior cruciate ligament reconstruction (ACLR) using a four-strand semitendinosus (ST) graft with adjustable femoral and tibial cortical fixation produced good outcomes compared to an ST/gracilis (ST/G) graft with femoral pin transfixation and tibial bioscrew fixation. Follow-up was 2 years.

METHODS

Patients older than 16 years who underwent primary isolated ACLR included for 1 year until August 2017 were eligible. The primary outcome measures were the subjective International Knee Documentation Committee (IKDC) score, isokinetic muscle strength recovery, and return to work within 2 years. The study was approved by the ethics committee.

RESULTS

Of 66 eligible patients, 60 completed the study and were included, 33 in the 4ST group and 27 in the ST/G group. Mean age was 30.5 ± 8.9 years in the 4ST group and 30.3 ± 8.5 in the ST/G group (n.s.). No significant between-group differences were found for mean postoperative subjective IKDC (4ST group, 80.2 ± 12.5; ST/G group, 83.6 ± 13.6; n.s.), side-to-side percentage deficits in isokinetic hamstring strength (at 60°/s: ST group, 17% ± 16%; ST/G group, 14% ± 11%; n.s.) or quadriceps strength (at 60°/s: ST group, 14% ± 12%; ST/G group, 19% ± 17%; n.s.), return to work, pain during physical activities, side-to-side differential laxity, balance, loss of flexion/extension, or surgical complications.

CONCLUSION

This trial demonstrates that functional outcomes after 4ST for ACLR with cortical fixations could be as good, although not better, than those obtained using ST/G. The 4ST technique spares the gracilis tendon, which thus preserves the medial sided muscle and thereby could improve function and limit donor-side morbidity.

LEVEL OF EVIDENCE

Level I.

Comparative Risk-Benefit Profiles of Individual Devices for Graft Fixation in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Network Meta-analysis

PURPOSE

To compare the efficacy and safety of individual devices for femoral and/or tibial graft fixation in anterior cruciate ligament (ACL) reconstruction.

METHODS

The PubMed, Embase, Cochrane Library, and Web of Science databases were searched from inception to December 12, 2018. Randomized controlled trials comparing individual devices for ACL graft fixation were included. Bayesian network meta-analysis was performed to assess the efficacy profile using the following outcomes: Lysholm score, International Knee Documentation Committee (IKDC) category, laxity, range of motion, and Tegner score. The incidence of infection, effusion, and graft rupture for each device was reported.

RESULTS

We included 57 randomized controlled trials involving 4,304 patients aged 23.8 to 40.9 years. The female proportion ranged from 0% to 100%. The length of follow-up ranged from 6 to 144 months. Of the 13 studied femoral fixation devices, none was significantly different from the others regarding the Lysholm score, IKDC category, range of motion, and Tegner score. Bioabsorbable interference screws (standardized mean difference, 1.3; 95% credible interval, 0.0-2.5) showed higher laxity than the EndoPearl at a borderline level of statistical significance, but the difference varied substantially within multiple sensitivity analyses. Infection (2.0%) was most commonly seen with the EndoPearl, whereas the bone mulch screw had the highest incidence of effusion (5.5%) and graft rupture (5.5%). For the 9 studied tibial fixation devices, no significant difference was observed in the aforementioned efficacy measurements. Bioabsorbable interference screws with staples had the highest incidence of infection (11.1%) and effusion (15.6%), whereas graft rupture was most commonly seen with the bone plug (4.0%).

CONCLUSIONS

Graft fixation devices in ACL reconstruction share a similar efficacy profile in terms of the Lysholm score, IKDC category, range of motion, and Tegner score but not laxity. On the other hand, safety profiles seem to vary among different devices. These findings can support surgeons, alongside their experience and preference, as well as the relative cost of each device, in delivering an individualized plan for an optimal operation.

LEVEL OF EVIDENCE

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

Comparison of clinical results of anteromedial and transtibial femoral tunnel drilling in ACL reconstruction

BACKGROUND

A femoral bone tunnel in ACL reconstruction can be constructed from the outside in or from the inside out. When doing it inside out, the approach can be via the anteromedial (AM) portal or through the tibial bone tunnel. It has been suggested that better results might be expected by doing it anteromedially. Clinical results after femoral tunnel drilling via the AM or transtibial (TT) techniques in reconstruction of anterior cruciate ligament (ACL) are presented.

METHODS

Three hundred patients with ACL injuries were chosen for this study from previously collected data on ACL reconstructions. They were divided into two groups: 150 patients treated with AM drilling and 150 treated with TT drilling. In the AM group, the reconstructions were performed using a semitendinosus graft with the Tape Locking Screw (TLS™) technique (n = 87) or Retrobutton™ femoral and BioScrew™ tibial fixation with a semitendinosus-gracilis graft (n = 63). In the TT group, the fixation method used was Rigidfix™ femoral and Intrafix tibial fixation with a semitendinosus-gracilis graft. The evaluation methods were clinical examination, knee scores (Lysholm, Tegner and IKDC) and instrumented laxity measurements (KT-2000™). Our aim was to evaluate if there was better rotational stability and therefore better clinical results when using AM drilling compared to TT drilling.

RESULTS

After excluding revision ACL reconstructions, there were 132 patients in the AM group and 133 in the TT group for evaluation. At the 2-year follow-up, there were 60 patients in the AM group (45.5%) and 58 in the TT group (43.6%). There were no statistically significant differences between the groups in any of the evaluation methods used.

CONCLUSION

Both drilling techniques resulted in improved patient performance and satisfaction. We found no data supporting the hypothesis that the AM drilling technique provides better rotational stability to the knee.

TRIAL REGISTRATION

ISRCTN registry with study ID ISRCTN16407730. Retrospectively registered Jan 9th 2020.

No difference in outcomes between femoral fixation methods with hamstring autograft in anterior cruciate ligament reconstruction - A network meta-analysis

BACKGROUND

There is mixed opinion regarding the optimal femoral fixation method for hamstring tendon autograft in anterior cruciate ligament (ACL) reconstruction. Currently, no study exists showing a superior method of femoral fixation, and thus the topic has remained controversial. The purpose of this study is to network meta-analyze the randomized control trials comparing cortical-button (CB), cross-pin (CP) and interference screws (IS) for femoral fixation with hamstring tendon autograft in ACL reconstruction.

METHODS

The literature review was conducted in accordance with the PRISMA guidelines. Randomized control trials comparing CB, CP and IS were included. Clinical outcomes were compared using a frequentist approach to network meta-analysis, with all statistical analysis performed using R, with a p-value <0.05 being considered statistically significant.

RESULTS

There were 11 studies included comparing; 194 patients with CB to 201 patients with CP (6 studies), 48 patients with CB to 50 patients with IS (1 study), and 172 patients with CP to 162 patients with IS (5 studies). One study compared all three groups, including 48 patients with CB, 50 patients with IS, and 52 with CP. There was a mean follow-up time of 26.4 months. No statistically significant difference was found between the fixation methods when evaluating knee stability, functional outcomes, graft failures, or revision procedures.

CONCLUSION

Using a network meta-analysis, our study found that, there was no difference in failure rate, knee stability, functional outcomes or incidence of revision procedures between CB, CP or IS femoral fixation techniques of hamstring tendon autografts in ACL reconstruction.

LEVEL OF EVIDENCE

Level I, network meta-analysis of Level I studies.

Tibial Interference Screw Positioning Relative to the Bone Plug in ACL Reconstruction: A Biomechanical Comparison of Cortical Versus Cancellous-Sided Placement

The biomechanical strength of a bone-patellar tendon-bone graft in the tibia may vary depending on whether the interference screw abuts the cancellous vs the cortical surface of the bone plug. In a porcine model, 10×20-mm bone-patellar tendon-bone grafts were prepared and fixed in a 10-mm diameter tibial tunnel using a 9×25-mm titanium interference screw. The screw was positioned on the cancellous surface of the graft in group A (n=13) vs the cortical side of the graft in group B (n=14). Specimens underwent precycling, cyclic loading, and load-to-failure testing. The mean ultimate failure load was 493±245 N for group A vs 304±145 N for group B (P=.008). Sixty-nine percent of specimens in group A survived 1000 cycles of load testing compared with 21% of specimens in group B. Forty-three percent of specimens in group B sustained intratendinous failure adjacent to the bone plug compared with 15% of specimens in group A. Orientation of the tibial interference screw along the cancellous vs the cortical side of the graft results in superior cyclic loading and ultimate failure load characteristics. Additionally, screw placement along the cortical side may weaken the tendon interface and lead to tendon failure under load. This study indicates that placement of the tibial interference screw along the cancellous side of the graft is biomechanically favorable. However, the clinical ramifications of these findings are not clear. [Orthopedics. 2018; 41(6):337-342.].

Passive anterior tibia translation in anterior cruciate ligament-injured, anterior cruciate ligament-reconstructed and healthy knees: a systematic review

Abstract

Anterior tibia translation (ATT) is mainly prevented by the anterior cruciate ligament. Passive ATT tests are commonly used to diagnose an anterior cruciate ligament (ACL) injury, to select patients for an ACL reconstruction (ACLR), and as an outcome measure after an ACLR. The aim of this review was to present an overview of possible factors determining ATT. A second purpose was to give a summary of the ATT measured in the literature in healthy, ACL-injured and ACLR knees and a comparison between those groups. A literature search was conducted with PubMed. Inclusion criteria were full-text primary studies published in English between January 2006 and October 2016. Studies included reported ATT in explicit data in healthy as well as ACL-injured or ACLR knees or in ACL-injured as well as ACLR knees. Sixty-one articles met inclusion criteria. Two articles measured the ATT in healthy as well as ACL-injured knees, 51 in ACL-injured as well as in ACLR knees, three in ACLR as well as in healthy knees and three in healthy, ACL-injured and ACLR knees. A difference in ATT is found between healthy, contralateral, ACLR and ACL-injured knees and between chronic and acute ACL injury. Graft choices and intra-articular injuries are factors which could affect the ATT. The mean ATT was lowest to highest in ACLR knees using a bone–patella tendon–bone autograft, ACLR knees using a hamstring autograft, contralateral healthy knees, healthy knees, ACLR knees with an allograft and ACL-injured knees. Factors which could affect the ATT are graft choice, ACL injury or reconstruction, intra-articular injuries and whether an ACL injury is chronic or acute. Comparison of ATT between studies should be taken with caution as a high number of different measurement methods are used. To be able to compare studies, more consistency in measuring devices used should be introduced to measuring ATT. The clinical relevance is that an autograft ACLR might give better results than an allograft ACLR as knee laxity is greater when using an allograft tendon.

Level of evidence

III.

Meta-analysis of the Risk of Infections After Anterior Cruciate Ligament Reconstruction by Graft Type

BACKGROUND

An infection after anterior cruciate ligament (ACL) reconstruction is a relatively rare but challenging complication. There are no meta-analyses comparing the incidence of infections after ACL reconstruction with the various available graft choices.

PURPOSE

To compare the incidence of infections after ACL reconstruction with bone-patellar tendon-bone (BPTB) autografts compared with hamstring autografts, with a secondary aim of comparing the incidence of infections after reconstruction with autografts compared with allografts.

STUDY DESIGN

Meta-analysis.

METHODS

A systematic review was performed to identify level 1 and 2 studies that reported the incidence of infections by graft type after ACL reconstruction. Studies that evaluated patients undergoing primary ACL reconstruction with an autograft, allograft, or combination of autograft and allograft and reported the number of postoperative infections by graft type utilized were considered for inclusion. Studies were excluded if they included revision ACL reconstruction or did not specify the number of infections by graft type. Study findings were reviewed, and meta-analysis was performed when data were sufficiently homogeneous.

RESULTS

Twenty-one studies meeting criteria were identified from the literature review. Meta-analysis revealed a significant difference in the incidence of deep infections between BPTB autografts and hamstring autografts, with the BPTB group displaying a 77% lower incidence of infections compared with the hamstring group (relative risk [RR], 0.23; 95% CI, 0.097-0.54). The incidence of infections was 66% lower with BPTB autografts compared with all other graft types, with a pooled RR of 0.33 (95% CI, 0.15-0.71). There was no significant difference in the incidence of infections after ACL reconstruction with autografts compared with allografts (RR, 1.035; 95% CI, 0.589-1.819).

CONCLUSION

The findings of this meta-analysis demonstrate a significantly lower incidence of deep infections after ACL reconstruction with BPTB autografts compared with hamstring autografts but not compared with allografts.

CLINICAL RELEVANCE

Although the overall infection rate after ACL reconstruction is relatively low, the significantly higher rate of infections with hamstring autografts compared with BPTB autografts should be a consideration when discussing graft choices for ACL reconstruction.

Graft fixation influences revision risk after ACL reconstruction with hamstring tendon autografts

Background and purpose - A large number of fixation methods of hamstring tendon autograft (HT) are available for anterior cruciate ligament reconstruction (ACLR). Some studies report an association between fixation method and the risk of revision ACLR. We compared the risk of revision of various femoral and tibial fixation methods used for HT in Scandinavia 2004-2011. Materials and methods - A register-based study of 38,666 patients undergoing primary ACLRs with HT, with 1,042 revision ACLRs. The overall median follow-up time was 2.8 (0-8) years. Fixation devices used in a small number of patients were grouped according to design and the point of fixation. Results - The most common fixation methods were Endobutton (36%) and Rigidfix (31%) in the femur; and interference screw (48%) and Intrafix (34%) in the tibia. In a multivariable Cox regression model, the transfemoral fixations Rigidfix and Transfix had a lower risk of revision (HR 0.7 [95% CI 0.6-0.8] and 0.7 [CI 0.6-0.9] respectively) compared with Endobutton. In the tibia the retro interference screw had a higher risk of revision (HR 1.9 [CI 1.3-2.9]) compared with an interference screw. Interpretation - The choice of graft fixation influences the risk of revision after primary ACLR with hamstring tendon autograft.

Cross Pin Versus Interference Screw for Femoral Graft Fixation in Hamstring Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Clinical Outcomes

PURPOSE

To compare the effectiveness of a cross pin and interference screw for femoral graft fixation in primary anterior cruciate ligament reconstruction (ACLR) and provide an appropriate reference for orthopaedic surgeons.

METHODS

The Medline, Cochrane Library, Web of Science, Scopus, and PubMed databases were searched in March 2016, and comparative trials using cross-pin and interference screw devices for femoral graft fixation in primary hamstring ACLR with clinical outcome measurements were included in the review. Trials with no controlled groups, hybrid fixation, no clinical outcomes, or follow-up of less than 1 year were excluded. The quality of the included studies was assessed with the Cochrane Back Review Group 12-item scale. Abstracted data were pooled with fixed or random effects depending on the detected heterogeneity. The outcome measures were the scoring system and physical examination findings, including the Lysholm score, International Knee Documentation Committee score or grade, Tegner score, negative Lachman test, negative pivot-shift test, and instrumented side-to-side anterior-posterior laxity difference.

RESULTS

All the studies reviewed were of prospective design. Within the cross-pin group, patients who underwent hamstring ACLR showed a significantly smaller instrumented side-to-side anterior-posterior laxity difference when compared with interference screw fixation (weighted mean difference, 0.38 mm [95% confidence interval, 0.08-0.67 mm]; P = .01), whereas the results of a negative Lachman test and negative pivot-shift test were comparable. Outcomes regarding the scoring system did not reach a significant difference between the 2 groups.

CONCLUSIONS

The statistically decreased instrumented side-to-side anterior-posterior laxity difference achieved by cross-pin transfixation appears to be of limited clinical significance when compared with interference screw fixation in primary hamstring ACLR. Clinically, the performance of cross-pin devices did not show a significant advantage over that of the interference screw for femoral graft fixation in hamstring ACLR.

LEVEL OF EVIDENCE

Level II.

Hamstring Autograft versus Patellar Tendon Autograft for ACL Reconstruction: Is There a Difference in Graft Failure Rate? A Meta-analysis of 47,613 Patients

BACKGROUND

Bone-patellar tendon-bone (bone-tendon-bone) and four-strand hamstring tendon grafts (hamstring) are the most commonly utilized autografts for primary anterior cruciate ligament (ACL) reconstruction. Existing clinical trials, registry studies, and meta-analyses offer conflicting opinions regarding the most favorable graft choice.

QUESTIONS/PURPOSES

Which graft type for ACL reconstruction (bone-tendon-bone or hamstring) has a higher risk of (1) graft rupture and/or (2) graft laxity?

METHODS

We performed a meta-analysis of randomized controlled trials (RCTs), prospective cohort studies, and high-quality national registry studies to compare the outcomes of primary ACL reconstruction with bone-tendon-bone autograft or hamstring autograft. Studies that compared these graft types were identified through a comprehensive search of electronic databases (PubMed, MEDLINE, EMBASE, and the Cochrane Library). Two independent reviewers utilized the Jadad scale for RCT study quality and the Modified Coleman Methodology Score for prospective comparative and registry study quality. The included studies were analyzed for the primary outcome measure of graft rupture with or without revision ACL surgery. In surviving grafts, secondary outcomes of graft laxity were quantified by KT1000/2000™ testing, a positive pivot shift test, and a positive Lachman test. Meta-analysis was performed with Review Manager. A total of 47,613 ACL reconstructions (39,768 bone-tendon-bone and 7845 hamstring) from 14 RCTs, 10 prospective comparative studies, and one high-quality national registry study were included in this meta-analysis. Mean age was 28 years in both groups. Sixty-three percent of patients in the bone-tendon-bone cohort were men versus 57% of patients in the hamstring cohort. Mean followup was 68 ± 55 months.

RESULTS

Two hundred twelve of 7560 (2.80%) bone-tendon-bone grafts ruptured compared with 1123 of 39,510 (2.84%) in the hamstring group (odds ratio = 0.83, 95% confidence interval, 0.72-0.96; p = 0.01). The number needed to treat analysis found that 235 patients would need to be treated with a bone-tendon-bone graft over a hamstring tendon graft to prevent one graft rupture. Instrumented laxity analysis showed that 22% (318 of 1433) of patients in the bone-tendon-bone group had laxity compared with 18% (869 of 4783) in the hamstring tendon group (odds ratio = 0.86; p = 0.16). Pivot shift analysis showed a positive pivot shift in 19% (291 of 1508) of the bone-tendon-bone group compared with 17% (844 of 5062) in the hamstring group (odds ratio = 0.89; p = 0.51). Lachman testing showed a positive Lachman in 25% (71 of 280) of patients receiving bone-tendon-bone grafts compared with 25% (73 of 288) in the hamstring group (odds ratio = 0.96; p = 0.84).

CONCLUSIONS

In this meta-analysis of short- to mid-term followup after primary ACL reconstruction, hamstring autografts failed at a higher rate than bone-tendon-bone autografts. However, failure rates were low in each group, the difference observed was small, and we observed few differences between graft types in terms of laxity. Both graft types remain viable options for primary ACL reconstruction, and the difference in failure rate should be one part of a larger conversation with each individual patient about graft selection that should also include potential differences in donor site morbidity, complication rates, and patient-reported outcome measures. Continued prospective collection of patient data will be important going forward as we attempt to further characterize the potential differences in outcomes attributable to graft selection.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Suspensory Versus Aperture Fixation of a Quadrupled Hamstring Tendon Autograft in Anterior Cruciate Ligament Reconstruction: A Meta-analysis

BACKGROUND

Hamstring grafts have become a popular choice for anterior cruciate ligament (ACL) reconstruction; however, the most effective means of fixation of these soft tissue grafts is unknown.

PURPOSE

To determine whether suspensory or aperture fixation of hamstring tendon autografts provides better stability and clinical outcomes in ACL reconstruction.

STUDY DESIGN

Meta-analysis.

METHODS

A literature search of studies reporting single-bundle ACL reconstructions using 4-stranded hamstring tendon autografts with aperture or suspensory fixation with a minimum 24-month follow-up was conducted. Stability and clinical outcomes were compared for aperture versus suspensory fixation. Knee stability was measured with the Lachman or pivot-shift test or KT-1000 arthrometer side-to-side difference (SSD), and outcomes were determined with the International Knee Documentation Committee (IKDC), Tegner, and Lysholm scores as well as graft failures. A random-effects model with a pooled estimate for the between-study variance was used to estimate proportions or means for each outcome and its corresponding 95% CI.

RESULTS

Forty-one studies were included, of which 20 utilized suspensory fixation techniques and 21 utilized aperture fixation techniques. A >3-mm SSD was seen more often in the aperture group than the suspensory group, which was statistically significant ( P < .0001), but there was no significant difference between groups for a >5-mm SSD ( P = .53). The aperture group demonstrated significantly more graft ruptures than did the suspensory group ( P = .03). There were no statistically significant differences in Lachman grade 0 ( P = .76), grade 1 ( P = .89), and grade 2 ( P = .55) or pivot-shift grade 0 ( P = .72), grade 1 ( P = .97), and grade 2 ( P = .28). There was no statistically significant difference in mean continuous IKDC ( P = .80), Tegner ( P = .34), or Lysholm ( P = .84) scores.

CONCLUSION

This meta-analysis demonstrated improved overall arthrometric stability and fewer graft ruptures using suspensory fixation compared with aperture fixation of a quadrupled hamstring tendon autograft in ACL reconstruction. There were no differences in IKDC, Lysholm, Lachman, and pivot-shift outcomes between suspensory and aperture fixation.

Comparison of Outcomes of Two Femoral Fixation Devices in Hamstring Anterior Cruciate Ligament Reconstruction

BACKGROUND

Tear of the anterior cruciate ligament (ACL) is a common ligamentous injury of the knee. Reconstruction of this ligament is often required to restore functional stability of the knee. Outcome of ACL reconstruction is significantly affected by how the graft is fixed to the bone. This study is to determine if there is a different clinical outcome after cortical versus cortical-cancellous suspension femoral fixation in hamstring based anterior cruciate ligament (ACL) reconstruction.

MATERIALS AND METHODS

This is a retrospective comparative study conducted between 2006 and 2010. We enrolled patients who underwent arthroscopic ACL reconstruction. Sixty two patients met inclusion criteria and 41 agreed to come for followup assessment. Median age was of 28 years (range 18-39 years). Demographic baseline profile of both groups was similar. The femoral fixation devices were cortical (n = 16) and cortical-cancellous suspension techniques (n = 25). The average period of evolution at the time of assessment was 40 months (range 12-72 months). The patients were examined according to Lachman test (using Rolimeter knee tester), anterior drawer test, pivot shift test, International Knee Documentation Committee questionnaire, and Tegner-Lysholm knee scoring scale.

RESULTS

The objective evaluation of the patients (Lachman test) showed better results in terms of stability in the group of patients who underwent the cortical-cancellous suspension method. These differences were not reflected in the assessment of activity level (Tegner-Lysholm), where both groups showed the same results.

CONCLUSIONS

ACL reconstruction with both cortical and cortical-cancellous suspension femoral fixation techniques show the same clinical results at medium long followup. However, cortical-cancellous fixations seem to provide greater stability to the reconstruction.

Bioabsorbable versus metallic interference screws for graft fixation in anterior cruciate ligament reconstruction

BACKGROUND

Anterior cruciate ligament (ACL) tears are frequently treated with surgical reconstruction with grafts, frequently patella tendon or hamstrings. Interference screws are often used to secure the graft in bone tunnels in the femur and tibia. This review examines whether bioabsorbable interference screws give better results than metal interference screws when used for graft fixation in ACL reconstruction.

OBJECTIVES

To assess the effects (benefits and harms) of bioabsorbable versus metallic interference screws for graft fixation in ACL reconstruction.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, CENTRAL (the Cochrane Library), MEDLINE, Embase, LILACS, trial registers and reference lists of articles. Date of search: January 2016.

SELECTION CRITERIA

We included randomised controlled trials and quasi-randomised trials comparing bioabsorbable with metallic interferences screws in ACL reconstruction. The main outcomes sought were subjective-rated knee function, failure of treatment, and activity level.

DATA COLLECTION AND ANALYSIS

At least two review authors selected eligible trials, independently assessed risk of bias, and cross-checked data. Data were pooled whenever relevant and possible. Requests for further information were sent to the original study authors.

MAIN RESULTS

We included 12 trials (11 randomised and one quasi-randomised) involving a total of 944 participants, and reporting follow-up results for 774. Participants in the 12 trials underwent ACL reconstruction with either hamstring tendon grafts (five trials) or patellar tendon grafts (seven trials). Trials participants were randomly allocated to bioabsorbable or metallic interference screws for graft fixation in both femur and tibia (seven trials); femur only (three trials); tibia only (one trial); location was not reported in the remaining trial. A variety of materials was used for the bioabsorbable screws, Poly-L-lactic acid (PLLA) being the most common. The metallic screws, where reported, were titanium.All trials were at high risk of bias, which invariably included performance bias. Seven trials were at high risk of attrition bias and eight at high risk of reporting bias. The quasi-randomised trial was assessed as being at high risk for selection bias. Based on these study limitations and insufficiency of the available data, we judged the quality of evidence for all outcomes was very low.The majority of the available data for patient-reported knee function was presented as Lysholm scores (0 to 100; higher scores = better function). There was very low quality but consistent evidence of no clinically important differences between the two groups in Lysholm scores at 12 months follow-up (mean difference (MD) -0.08, 95% confidence interval (CI) -1.48 to 1.32; three trials, 168 participants); 24 months (MD 0.35, 95% CI -1.27 to 1.98; three trials, 113 participants) or five or more years follow-up (MD 1.23, 95% CI -2.00 to 4.47; two trials, 71 participants). This lack of between-group differences was also reported for Lysholm scores in several trials that did not provide sufficient data for pooling as well as for other self-reported knee function scores reported in several trials.Treatment failure was represented by the summed data for implant breakage during surgery and major postoperative complications (implant failure, graft rupture, symptomatic foreign body reactions, effusion and treated arthrofibrosis and related conditions) that were usually described in the trial reports as requiring further substantive treatment. There is very low-quality evidence of greater treatment failure in the bioabsorbable screw group (60/451 versus 29/434; risk ratio (RR) 1.94 favouring metallic screw fixation, 95% CI 1.29 to 2.93; 885 participants, 11 studies). In a population with an assumed risk (based on the median control group risk) of 56 participants per 1000 having treatment failure after metallic screw fixation, this equates to 53 more (95% CI 17 to 108 more) per 1000 participants having treatment failure after bioabsorbable screw fixation. All 16 intraoperative complications in the bioabsorbable screw group were implant breakages upon screw insertion. Treatment failure defined as postoperative complications only still favoured the metallic screw group but the 95% CI also included the potential for a greater risk of treatment failure after metallic screw fixation: 44/451 versus 29/434; RR 1.44, 95% CI 0.93 to 2.23. Based on the assumed risk of 56 participants per 1000 having postoperative treatment failure after metallic screw fixation, this equates to 25 more (95% CI 4 fewer and 69 more) per 1000 participants having this outcome after bioabsorbable screw fixation.There was very low-quality evidence of very similar activity levels in the two groups at 12 and 24 months follow-up measured via the Tegner score (0 to 10; higher scores = greater activity): 12 months (MD 0.08, 95% CI -0.39 to 0.55; 122 participants, two studies); 24 months (MD 0.01, 95% CI -0.54 to 0.57; 72 participants, two studies).

AUTHORS' CONCLUSIONS

There is very low-quality evidence of no difference in self-reported knee function and levels of activity between bioabsorbable and metallic interference screws for graft fixation in ACL reconstruction. There is very low-quality evidence that bioabsorbable screws may be associated with more overall treatment failures, including implant breakage during surgery. Further research does not appear to be a priority, but if undertaken, should also examine costs.

Effects of ACL Reconstructive Surgery on Temporal Variations of Cytokine Levels in Synovial Fluid

Anterior cruciate ligament (ACL) reconstruction restores knee stability but does not reduce the incidence of posttraumatic osteoarthritis induced by inflammatory cytokines. The aim of this research was to longitudinally measure IL-1β, IL-6, IL-8, IL-10, and TNF-α levels in patients subjected to ACL reconstruction using bone-patellar tendon-bone graft. Synovial fluid was collected within 24–72 hours of ACL rupture (acute), 1 month after injury immediately prior to surgery (presurgery), and 1 month thereafter (postsurgery). For comparison, a “control” group consisted of individuals presenting chronic ACL tears. Our results indicate that levels of IL-6, IL-8, and IL-10 vary significantly over time in reconstruction patients. In the acute phase, the levels of these cytokines in reconstruction patients were significantly greater than those in controls. In the presurgery phase, cytokine levels in reconstruction patients were reduced and comparable with those in controls. Finally, cytokine levels increased again with respect to control group in the postsurgery phase. The levels of IL-1β and TNF-α showed no temporal variation. Our data show that the history of an ACL injury, including trauma and reconstruction, has a significant impact on levels of IL-6, IL-8, and IL-10 in synovial fluid but does not affect levels of TNF-α and IL-1β.

Mechanical strength of four allograft fixation techniques for ruptured cranial cruciate ligament repair in dogs

OBJECTIVE

To test ex vivo mechanical properties of 4 allograft fixation techniques for cranial cruciate ligament (CCL) replacement.

SAMPLE

30 stifle joints from canine cadavers.

PROCEDURES

CCL-deficient stifle joints repaired by 1 of 4 techniques (n = 6/group) and CCL-intact stifle joints (control group; 6) were mechanically tested. Three repair techniques involved a patella-patella ligament segment (PPL) allograft: a tibial and femoral interference screw (PPL-2S), a femoral interference screw and the patella seated in a tapering bone tunnel in the tibia (PPL-1S), or addition of a suture and a bone anchor to the PPL-1S (PPL-SL). The fourth technique involved a deep digital flexor tendon (DDFT) allograft secured with transverse femoral fixation and stabilized with a tibial interference screw and 2 spiked washers on the tibia (DDFT-TF). The tibia was axially loaded at a joint angle of 135°. Loads to induce 3, 5, and 10 mm of femoral-tibia translation; stiffness; and load at ultimate failure with the corresponding displacement were calculated. Group means were compared with a multivariate ANOVA.

RESULTS

Mean ± SD load for the intact (control) CCL was 520.0 ± 51.3 N and did not differ significantly from the load needed to induce 3 mm of femoral-tibial translation for fixation techniques PPL-SL (422.4 ± 46.3 N) and DDFT-TF (654.2 ± 117.7 N). Results for the DDFT-TF were similar to those of the intact CCL for all outcome measures.

CONCLUSIONS AND CLINICAL RELEVANCE

The DDFT-TF yielded mechanical properties similar to those of intact CCLs and may be a viable technique to test in vivo.

Registry data highlight increased revision rates for endobutton/biosure HA in ACL reconstruction with hamstring tendon autograft: a nationwide cohort study from the Norwegian Knee Ligament Registry, 2004-2013

BACKGROUND

Compared with a patellar tendon autograft (PT), a hamstring tendon autograft (HT) has an increased risk of revision after anterior cruciate ligament reconstruction (ACLR). There are no studies analyzing whether this can be explained by inferior fixation devices used in HT reconstruction or whether the revision risk of ACLR with an HT or a PT is influenced by the graft fixation.

PURPOSE

To compare the risk of revision and the revision rates between the most commonly used combinations of fixation for HTs with PTs.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

This study included all patients registered in the Norwegian Knee Ligament Registry from 2004 through 2013 who underwent primary PT or HT ACLR with no concomitant ligament injury and known graft fixation. The 2-year revision rates were calculated using the Kaplan-Meier analysis. Hazard ratios (HRs) for revision at 2 years were calculated using multivariate Cox regression models.

RESULTS

A total of 14,034 patients with primary ACLR were identified: 3806 patients with PTs and 10,228 patients with HTs; the mean follow-up time was 4.5 years. In the HT group, 5 different combinations of fixation in the femur/tibia were used in more than 500 patients: Endobutton/RCI screw (n = 2339), EZLoc/WasherLoc (n = 1352), Endobutton/Biosure HA (n = 1209), Endobutton/Intrafix (n = 687), and TransFix II/metal interference screw (MIS) (n = 620). The crude 2-year revision rate for patients with PTs was 0.7% (95% CI, 0.4%-1.0%), and for patients with HTs, it ranged between the groups from 1.5% (95% CI, 0.5%-2.4%) for TransFix II/MIS to 5.5% (95% CI, 4.0%-7.0%) for Endobutton/Biosure HA. When adjusted for detected confounding factors and compared with patients with PTs, the HR for revision at 2 years was increased for all HT combinations used in more than 500 patients, and the combinations Endobutton/Biosure HA and Endobutton/Intrafix had the highest HRs of 7.3 (95% CI, 4.4-12.1) and 5.5 (95% CI, 3.1-9.9), respectively.

CONCLUSION

The choice of fixation after ACLR with an HT has a significant effect on a patient's risk of revision. In this study population, none of the examined combinations of HT fixation had a revision rate as low as that for a PT.

A randomized prospective controlled study with 5-year follow-up of cross-pin femoral fixation versus metal interference screw fixation in anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to determine and compare mid- to long-term results of cross-pin versus metal interference screw fixation of ACL graft.

METHODS

In a prospective trial, 62 patients were randomized into two groups based on method of fixation. Transtibial drilling technique was used in the cross-pin and outside-in femoral drilling in the interference screw fixation group. Clinical and radiographical outcomes were assessed 2 and 5 years postoperatively.

RESULTS

The study showed no clinically significant difference with respect to method of graft fixation. Mean anteroposterior side-to-side instrumented laxity difference was 2.4 mm in the cross-pin group and 2.5 mm in the screw group (n.s.). Median Tegner and mean Lysholm scores at 5 years were 6 (range 3-9) and 92.2 (range 69-100) in the screw group and 7 (3-10) and 93.3 (82-100), respectively, in the cross-pin group. Radiographical osteoarthritis increased in both groups from 2 to 5 years after reconstruction (p < 0.05), especially in the medial and patellofemoral joint spaces. Widening of the drill tunnels continued from 2 to 5 years without clinical significance.

CONCLUSIONS AND CLINICAL RELEVANCE

The method of graft fixation did not yield a difference in clinical or radiographical outcome at 5 years. Results were excellent in both groups.

LEVEL OF EVIDENCE

I.

Intratunnel versus extratunnel autologous hamstring double-bundle graft for anterior cruciate ligament reconstruction: a comparison of 2 femoral fixation procedures

BACKGROUND

Anatomic double-bundle anterior cruciate ligament (ACL) reconstruction provides excellent results for restoring normal kinematics to the knee. Nevertheless, strong evidence supporting an ideal method for fixation of the ACL graft is lacking.

HYPOTHESIS

Intratunnel femoral fixation of the ACL graft via a cross-pin fixation technique would provide better clinical and objective results than the extratunnel femoral fixation with cortical buttons.

STUDY DESIGN

Randomized clinical trial; Level of evidence, 2.

METHODS

Seventy patients with a unilateral ACL-deficient knee were randomly assigned to 1 of 2 femoral fixation groups. Group A (35 patients) was fixed with 2 bioabsorbable Rigidfix pins, 1 cross-pin per bundle, while group B (35 patients) was secured with 1 EndoButton cortical button per bundle. All femoral tunnels were created via an anteromedial portal, and a bioabsorbable Biointrafix interference screw was used for tibial fixation for both groups. The evaluation of the patients was performed by history details, clinical examination findings, measurement of the joint laxity by KT-1000 arthrometer, and use of validated patient outcome questionnaires. Statistical analysis was carried out with Fisher exact and Mann-Whitney U tests, with P<.05 considered the cutoff level of significance.

RESULTS

At a mean follow-up of 30 months, 34 and 32 patients of group A and B, respectively, were available for evaluation. There were no statistically significant differences between the treatment groups regarding the subjective and objective outcomes, except for KT-1000 arthrometer values. The median KT-1000 value of patients in the cross-pin fixation group was 1.30 mm, while the median value in the cortical button fixation group was 1.95 mm (P<.001). Four patients with ACL grafts that were fixed with cortical buttons demonstrated failure of stability via the instrumented knee laxity testing, while patients from the other group had no failures.

CONCLUSION

Intratunnel femoral fixation of the double-bundle ACL graft from the cross-pin fixation technique provided better instrumented knee laxity results than did the extratunnel femoral fixation with cortical buttons. Future larger studies comparing these 2 techniques should be conducted to ensure the availability of stronger evidence supporting the findings of this study.

Mechanical properties of canine patella-ligament-tibia segment

OBJECTIVE

To test the ex vivo mechanical properties of canine patella-ligament-tibia (PLT) segment and establish the relationship between donor size and PLT dimensions to the mechanical properties of PLT grafts.

STUDY DESIGN

Ex vivo mechanical testing study.

SAMPLE POPULATION

Canine PLT segments (n = 21 dogs; 42 PLT).

METHODS

Morphometric measurements of PLT segments were taken from computed tomography (CT) images and compared with results obtained using calipers. PLT were tested to failure at a rate of 100% length/s. Mechanical properties and failure mode were recorded.

RESULTS

PLT width and thickness (P < .001 for both) measured by calipers were significantly lower than those taken from CT images. Thirty-five (83%) specimens failed by avulsion fracture from the patella, 1 failed mid-ligament, and 6 failed by tibial fracture. Dog weight and PLT length had the strongest Pearson's r value when correlated with load at failure (r = 0.73, 0.81, respectively).

CONCLUSION

Dog weight and PLT length were the best predictors of load at failure. PLT failure load of dogs weighing >25 kg were similar to those reported for the cranial cruciate ligament (CCL) suggesting that the PLT may be a suitable allograft for CCL replacement.

Fixation techniques for the anterior cruciate ligament reconstruction: early follow-up. A systematic review of level I and II therapeutic studies

The purpose of our study was that to systematically review the fixation techniques for the ACL reconstruction and associated clinical outcomes at the early follow-up. Systematic search on three electronic databases (Cochrane register, Medline and Embase) of fixation devices used for primary ACL reconstruction with doubled semitendinosus and gracilis and bone-patellar tendon-bone autografts in randomized clinical trials of level I and II of evidence published from January 2001 to December 2011. Therapeutic studies collected were with a minimum 12-month follow-up, and the clinical outcomes were evaluated by at least one of International Knee Documentation Committee, Lysholm and Tegner functional scales and at least one of the following knee stability tests: arthrometric AP tibial translation, Lachman test and pivot-shift test. Nineteen articles met the inclusion criteria. At the femoral side cross-pin, metallic interference screw, bioabsorbable interference screw, and suspensory device were used in 32.3, 27.3, 24.8, 15.5% of patients, respectively. At the tibial side fixation was achieved with metallic interference screw, bioabsorbable interference screw, screw and plastic sheath, screw post and cross-pin in 38.7, 31, 15.7, 12.8, and 1.7% of patients, respectively. Side-to-side anterior-posterior tibial translation was 1.9 ± 0.9, 1.5 ± 0.9, 1.5 ± 0.8, 2.2 ± 0.4 mm for metallic interference screw, bioabsorbable screw, cross-pin and suspensory device, respectively. At least two-third of all the patients achieved good-to-excellent clinical outcomes. Rate of failure was 6.1, 3.3, 1.7 and 1.2% for bioabsorbable interference screw, metallic interference screw, cross-pin and suspensory device, respectively. Clinical outcomes are good to excellent in almost two-third of the patients but several pitfalls that affect the current fixation techniques as graft tensioning such as graft-tunnel motion are still unaddressed.

Clinical results of hamstring autografts in anterior cruciate ligament reconstruction: a comparison of femoral knot/press-fit fixation and interference screw fixation

PURPOSE

To compare the clinical outcomes of femoral knot/press-fit anterior cruciate ligament (ACL) reconstruction with conventional techniques using femoral interference screws.

METHODS

Among patients who underwent arthroscopic ACL reconstruction with hamstring autografts, 73 were treated with either a femoral knot/press-fit technique (40 patients, group A) or femoral interference screw fixation (33 patients, group B). The clinical results of the 2 groups were retrospectively compared. The inclusion criteria were primary ACL reconstruction in active patients. The exclusion criteria were fractures, multiligamentous injuries, patients undergoing revision, or patients with contralateral ACL-deficient knees. In the femoral knot/press-fit technique, semitendinosus and gracilis tendons were prepared as 2 loops with knots. After passage through a bottleneck femoral tunnel, the grafts were fixed with a press-fit method (grafts' knots were stuck in the bottleneck of the femoral tunnel). A tie with Mersilene tape (Ethicon, Somerville, NJ) over a bone bridge for each tendon loop and an additional bioabsorbable interference screw were used for tibial fixation.

RESULTS

The mean follow-up period was 38 months (range, 24 to 61 months). A significant improvement in knee function and symptoms was reported in most patients, as shown by improved Tegner scores, Lysholm knee scores, and International Knee Documentation Committee assessments (P < .01). The results of instrumented laxity testing, thigh muscle assessment, and radiologic assessment were clearly improved when compared with the preoperative status (P < .01). No statistically significant difference in outcomes could be observed between group A and group B (P = not significant).

CONCLUSIONS

In this nonrandomized study, femoral knot/press-fit ACL reconstruction did not appear to provide increased anterior instability compared with that of conventional femoral interference screw ACL reconstruction. Favorable outcomes with regard to knee stability and patient satisfaction were achieved in most of our ACL-reconstructed patients using femoral knot/press-fit fixation with hamstring tendon autograft.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Pre-tibial reaction to biointerference screw in anterior cruciate ligament reconstruction

BACKGROUND

We aim to report a series of cases that presented as pre-tibial swelling and pain following anterior cruciate ligament (ACL) reconstruction using bioabsorbable fixation devices.

METHODS

All ACL reconstructions done between 2007 and 2010 were reviewed retrospectively to identify complications related to bioabsorbable fixation devices. We performed 273 ACL reconstructions over a period of three years from 2007 to 2010 using a bioabsorbable screw for tibial fixation of the quadrupled hamstring autograft.

RESULTS

Fourteen patients (5%) at mean age of 30 (range 16-47) years, presented to us at a mean post-operative period of 26 months (range 12-39) with pre-tibial pain and swelling over the tibial screw site. All of them had normal inflammatory markers. All of these patients underwent surgical debridement, which revealed remnants of screw and reactive material. There was no evidence of infection in the intra-operative specimen cultures. Histopathology revealed a reactive appearance and surrounding myxoid changes. Removal of screw debris and curettage of the tunnel resulted in complete recovery of all patients at a mean follow up of 12 (range 8-16) months.

CONCLUSIONS

Pre-tibial cyst along with other adverse biological response should be considered as a possible complication in ACL reconstruction. We report an incidence of 5% of pre-tibial reaction in patients undergoing ACL reconstruction with bio-absorbable interference screw fixation for the proximal tibia.

A Comparison of Clinical Outcomes of Two Methods of Femoral Hamstring Graft Pin Fixation in Anterior Cruciate Ligament Reconstruction

The outcome of anterior cruciate ligament (ACL) reconstruction with hamstring grafts depends on early rehabilitation and secure graft fixation. Various devices available for graft fixation at the femoral tunnel have different biomechanical properties as demonstrated on cadaveric studies. The aim of this study was to compare clinical outcomes in patients using either of two methods of transfemoral pin fixation for hamstring grafts in ACL reconstruction. Twenty-eight patients undergoing primary ACL reconstruction with hamstring autograft with either transfemoral expansion fixation (Rigidfix) or cortical-cancellous suspension (Transfix) by a single surgeon were analysed including subjective knee scores and objective measurements including range of motion and arthrometer-measured anterior translation. Transfix was used in 14 (50.0%) patients and Rigidfix was used in 14 (50.0%) patients. There was no significant difference in pre-injury Tegner activity scores, pre-operative Tegner activity scores, Lysholm scores and age or in Tegner post-operative activity scores, Lysholm scores, range of motion, Lachman and pivot scores absolute anterior translation and anterior translation compared to the non-operated knee at two years. There was a significant improvement in Tegner (2.6 ± 2.4, p<0.00) and Lysholm (25.3 ± 21.2, p<0.00) scores at two years with no significant difference between the two groups. One patient had a broken Transfix cross-pin 13 months after surgery which presented as a subcutaneous swelling which was removed. Although the biomechanical properties of Rigidfix and Transfix differ as demonstrated in cadaveric studies, both devices had similar favourable clinical outcomes in our series.

Current trends in anterior cruciate ligament reconstruction

The advances in the knowledge of anatomy, surgical techniques, and fixation devices have led to the improvement of anterior cruciate ligament (ACL) reconstruction over the past 10 years. Nowadays, double bundle and anatomical single bundle ACL reconstruction that more closely restores the normal anatomy of the ACL are becoming popular. Although there is still no definite conclusion whether double bundle ACL reconstruction provides better clinical results than single bundle reconstruction, the trend has shifted to anatomic reconstruction regardless of single bundle or double bundle techniques. We could not find any significant differences in the clinical outcomes and stability after ACL reconstruction according to the type of graft or fixation device. Therefore, surgeons should select an ideal ACL reconstruction according to the patient's condition and surgeon's experience.

Graft failure versus graft fixation in ACL reconstruction: histological and immunohistochemical studies in rabbits

The causes of graft failure after anterior cruciate ligament (ACL) reconstruction are multifactorial including the methods of graft fixation. The purpose of this study was to examine the ACL graft failure in three different methods of graft fixations including interference screw fixation, suture-post fixation and combined interference screw and suture-post fixation. We hypothesized that the fixation method after ACL reconstruction can affect the graft healing in tibial tunnel. Eighteen New Zealand white rabbits were categorized into three groups according to the method of fixation in unilateral ACL reconstruction with long digital extensor autograft. Histological examination demonstrated that the combined fixation and suture-post fixation groups showed significantly better integration between tendon and bone (P = 0.04). In immunohistochemical analysis, the combined fixation and suture-post fixation groups showed significantly higher BMP-2 and VEGF expressions than interference screw (P < 0.01). The tendon-bone healing after ACL reconstruction was affected by the method of graft fixation. Combined fixation with interference screw and suture-post reduced graft-tunnel micromotion and improved the graft healing in tibial tunnel.

Pullout strength of bone-patellar tendon-bone allograft bone plugs: a comparison of cadaver tibia and rigid polyurethane foam

PURPOSE

To compare the load-to-failure pullout strength of bone-patellar tendon-bone (BPTB) allografts in human cadaver tibias and rigid polyurethane foam blocks.

METHODS

Twenty BPTB allografts were trimmed creating 25 mm × 10 mm × 10 mm tibial plugs. Ten-millimeter tunnels were drilled in 10 human cadaver tibias and 10 rigid polyurethane foam blocks. The BPTB anterior cruciate ligament allografts were inserted into these tunnels and secured with metal interference screws, with placement of 10 of each type in each material. After preloading (10 N), cyclic loading (500 cycles, 10 to 150 N at 200 mm/min) and load-to-failure testing (200 mm/min) were performed. The endpoints were ultimate failure load, cyclic loading elongation, and failure mode.

RESULTS

No difference in ultimate failure load existed between grafts inserted into rigid polyurethane foam blocks (705 N) and those in cadaver tibias (669 N) (P = .69). The mean rigid polyurethane foam block elongation (0.211 mm) was less than that in tibial bone (0.470 mm) (P = .038), with a smaller standard deviation (0.07 mm for foam) than tibial bone (0.34 mm).

CONCLUSIONS

All BPTB grafts successfully completed 500 cycles. The rigid polyurethane foam block showed less variation in test results than human cadaver tibias.

CLINICAL RELEVANCE

Rigid polyurethane foam blocks provide an acceptable substitute for human cadaver bone tibia for biomechanical testing of BPTB allografts and offer near-equivalent results.

Improvement of primary stability in ACL reconstruction by mesh augmentation of an established method of free tendon graft fixation. A biomechanical study on a porcine model

PURPOSE

The aim of the present study was to compare primary stability in ACL reconstruction and ultimate load to failure of a mesh augmented hamstring tendon graft fixed with two cross pins to established hamstrings and bone-patellar-tendon-bone (BTB) graft fixation methods.

METHODS

Forty fresh porcine femora were divided into four groups: (A): BTB graft fixed with two RigidFix® pins, (B): hamstring tendon graft fixed with a Milagro® interference screw, (C): hamstring tendon graft fixed with two RigidFix® pins, and (D): hamstring tendon graft augmented with Ultrapro® mesh fixed with two RigidFix® pins. Each graft underwent cyclic loading in tension and load to failure. Elastic and plastic displacements were measured by 3-dimensional digital image correlation. Groups were compared by one-way ANOVA and Tukey-Kramer post-hoc tests.

RESULTS

After 1000 cycles, the mean plastic displacement was lowest in the BTB graft (p < 0.001). Plastic displacement was significantly lower in the mesh augmented group compared to the plain hamstring graft and the Milagro screw group (p < 0.05). Load to failure was highest in the mesh-augmented group; significant to the hamstring tendon (p = 0.023).

CONCLUSION

Although the BTB-graft represented the most stable construct against plastic displacement in our study, mesh augmentation of free tendon grafts significantly increased primary stability and reduced plastic displacement of femoral cross pin fixation. This new augmentation device may better protect the hamstrings graft from secondary elongation during postoperative rehabilitation.

CLINICAL RELEVANCE

Mesh augmentation seems to be an effective technique to stabilise free hamstring tendon autografts during postoperative rehabilitation with significant reduction of graft slippage.

Lateral meniscal tear resulting from the femoral cross-pin used for hamstring graft fixation in anterior cruciate ligament reconstruction

We report a case of lateral meniscal tear resulting from the femoral cross-pin used for hamstring graft fixation in anterior cruciate ligament (ACL) reconstruction. A 29 year old man presented with symptoms of knee pain, catching and locking, 13 months following an ACL reconstruction. Magnetic resonance imaging (MRI) and arthroscopy confirmed the broken femoral cross-pin abutting the lateral meniscus and the resulting meniscal tear. Removal of the broken femoral cross-pin and repair of the lateral meniscal tear resulted in resolution of symptoms. Distal femoral cross-pin fracture and its intra-articular position are postulated as the cause of this lateral meniscal tear. Hence, we recommend a low threshold to investigate with a MRI scan any new symptoms following ACL reconstruction with cross-pin fixation.

Breakage of bioabsorbable femoral transfix screw after arthroscopic anterior cruciate ligament repair: a report of two cases

The reconstruction of anterior cruciate ligament (ACL) has become the standard of care for a torn ACL in active, young athletes. Various methods, graft options and techniques of reconstruction are published. The use of biotransfix bioabsorbable screw is one of the options of anchoring the graft on the femoral side. We describe the failure of transfix due to breakage in two patients after arthroscopic ACL reconstruction. These patients developed symptoms of screw irritation subcutaneously or skin penetration of the broken, migrated transfix pin. The clinical presentation, diagnosis, the image findings, management and review of literature are presented in this report. To the best of our knowledge, this is the only report from Asia.

Bio-interference screw cyst formation in anterior cruciate ligament reconstruction--10-year follow up

PURPOSE

This study used serial MRI to assess the absorption of a poly l-lactide Bioabsorbable interference screw used in the anterior cruciate ligament reconstruction with a 4-strand hamstring technique.

METHODS

A consecutive series of ten patients undergoing anterior cruciate ligament reconstruction a 4-strand hamstring technique were assessed with magnetic resonance imaging (MRI) scans at 1, 2, 4, 7 and 10 years postoperatively.

RESULTS

No resorption had occurred after 4 years in any of the patients. By 7 years screw absorption was complete in seven patients and had progressed in three. New cyst formation occurred in 3 patients between 5 and 7 years. Half the patients displayed small fluid collections within the tibial tunnels. At 10 years all screws were fully absorbed; however cyst formation was common, including the development of a new cyst in the period between 7 and 10 years in one patient. None of the patients had instability, persistent effusions, or clinically detectable adverse reactions to the screws.

CONCLUSIONS

This study has shown that poly l-lactide bioabsorbable screws take longer to resorb than initial in vitro data suggested. It is unclear whether ganglion formation within the tibial tunnel is related to screw resorption or the hamstring graft. The theoretical advantages of bioabsorbable screws must be weighed against these findings.

Revision anterior cruciate ligament reconstruction: an update

With the rising number of anterior cruciate ligament (ACL) reconstructions performed, revision ACL reconstruction is increasingly common nowadays. A broad variety of primary and revision ACL reconstruction techniques have been described in the literature. Recurrent instability after primary ACL surgery is often due to non-anatomical ACL graft reconstruction and altered biomechanics. Anatomical reconstruction must be the primary goal of this challenging revision procedure. Recently, revision ACL reconstruction has been described using double bundle hamstring graft. Successful revision ACL reconstruction requires an exact understanding of the causes of failure and technical or diagnostic errors. The purpose of this article is to review the causes of failure, preoperative evaluation, graft selection and types of fixation, tunnel placement, various types of surgical techniques and clinical outcome of revision ACL reconstruction.

A systematic review of randomized controlled clinical trials comparing hamstring autografts versus bone-patellar tendon-bone autografts for the reconstruction of the anterior cruciate ligament

OBJECTIVES

Controversies exist over which type of graft is best for the reconstruction of the anterior cruciate ligament (ACL). The purpose of this systematic review was to evaluate the effectiveness of ACL reconstruction using either hamstring (HT) autografts or bone-patellar tendon-bone (BPTB) autografts.

METHODS

We searched the Cochrane Library, MEDLINE and EMBASE for published randomized controlled trials (RCT) comparing HT autografts with BPTB autografts for ACL reconstruction. Data analyses were performed using Cochrane Collaboration RevMan 5.0.

RESULTS

Nine RCTs (738 patients) met the inclusion criteria. The combined results of the meta-analysis indicated there was a significantly lower rate of negative Pivot test [relative risk (RR) 0.87, 95 % confidence intervals (CI) 0.79-0.96, P = 0.004], anterior knee pain (RR 0.66, 95 % CI 0.45-0.96, P = 0.03) and of kneeling pain (RR 0.49, 95 % CI 0.27-0.91, P = 0.02) in the HT group than in the BPTB group.

CONCLUSIONS

ACL reconstruction with HT autografts or BPTB autografts achieved similar postoperative effects in terms of restoring knee joint function. HT autografts were inferior to BPTB autografts for restoring knee joint stability, but were associated with fewer postoperative complications.