Hamstring tendon autograft better than bone patellar-tendon bone autograft in ACL reconstruction: a cumulative meta-analysis and clinically relevant sensitivity analysis applied to a previously published analysis

Validation of a Risk Calculator to Personalize Graft Choice and Reduce Rupture Rates for Anterior Cruciate Ligament Reconstruction

BACKGROUND

Anterior cruciate ligament reconstructions (ACLRs) fail at an alarmingly high rate in young active individuals. The Multicenter Orthopaedic Outcomes Network (MOON) knee group has developed an autograft risk calculator that uses patient characteristics and lifestyle to predict the probability of graft rupture if the surgeon uses a hamstring tendon (HT) or a bone-patellar tendon-bone (BPTB) graft to reconstruct the ligament. If validated, this risk calculator can be used during the shared decision-making process to make optimal ACLR autograft choices and reduce rupture rates. The STABILITY 1 randomized clinical trial offers a large, rigorously collected data set of similar young active patients who received HT autograft with or without lateral extra-articular tenodesis (LET) for ACLR.

PURPOSE/HYPOTHESIS

The purpose was to validate the ACLR graft rupture risk calculator in a large external data set and to investigate the utility of BPTB and LET for ACLR. We hypothesized that the risk calculator would maintain adequate discriminative ability and calibration in the external STABILITY 1 data set when compared with the initial MOON development data set.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 1.

METHODS

The model predictors for the risk calculator include age, sex, body mass index, sport played at the time of injury, Marx Activity Score, preoperative knee laxity, and graft type. The STABILITY 1 trial data set was used for external validation. Discriminative ability, calibration, and diagnostic test validity of the model were assessed. Finally, predictor strength in the initial and validation samples was compared.

RESULTS

The model showed acceptable discriminative ability (area under the curve = 0.73), calibration (Brier score = 0.07), and specificity (85.3%) to detect patients who will experience a graft rupture. Age, high-grade preoperative knee laxity, and graft type were significant predictors of graft rupture in young active patients. BPTB and the addition of LET to HT were protective against graft rupture versus HT autograft alone.

CONCLUSION

The MOON risk calculator is a valid predictor of ACLR graft rupture and is appropriate for clinical practice. This study provides evidence supporting the idea that isolated HT autografts should be avoided for young active patients undergoing ACLR.

REGISTRATION

NCT00463099 (MOON); NCT02018354 (STABILITY 1) (ClinicalTrials.gov identifiers).

Anatomic Anterior Cruciate Ligament Reconstruction Using Rectangular Bone-Tendon- Bone Autograft Versus Double-Bundle Hamstring Tendon Autograft in Young Female Athletes

Purpose

To assess the clinical outcomes comparing rectangular bone–tendon–bone (BTB) grafts and double-bundle hamstring tendon (HM) grafts used for anatomic anterior cruciate ligament (ACL) reconstruction in young female athletes.

Methods

From January 2014 to November 2017, young female athletes 20 years or younger who underwent primary ACL reconstructions by a single surgeon were identified. Patients with concomitant injuries, not being a regular sports participant, the existence of contralateral ACL reconstruction, and who did not have a minimum of 1-year follow-up were excluded. We searched the rate and time for return-to-play, clinical outcomes including chronological instrumental side-to-side tibial translation difference, and muscle strength. Second ACL injury rates between the 2 groups during follow-up period were evaluated.

Results

Twenty-seven BTB ACL reconstructions and 29 HM ACL reconstructions were performed. The mean follow-up periods were 35.2 months in the BTB group and 33.8 months in the HM group. The BTB group showed better knee stability in mean side-to-side translational difference via arthrometric testing of 0.6 mm in the BTB versus 1.7 mm in the HM group at 5 months (P = .01) and 1.1 mm and 2.0 mm at 12 months, respectively (P = .02). There was no significant side-by-side difference in quadriceps muscle strength ratio, but the hamstring muscle strength was significantly better in the BTB group. The graft reinjury rate in the BTB group and the HM group was 0% (0/27) and 10.3% (3/29) (P = .09), respectively. In contrast, contralateral ACL injuries occurred in 17.3% (4/27) of the BTB group and 3.5% (1/29) of the HM group (P = .12).

Conclusions

For young female athletes aged 20 years or younger, the BTB group had better knee instrumental stability than the HM group without range of motion loss or knee extensor muscle strength deficit. Although there was no statistical significance in terms of second ACL injury, we observed fewer graft rerupture and an increasing rate of contralateral ACL injuries in the BTB group.

Level of Evidence

Level III, retrospective comparative study.

Evidence-Based Research Series-Paper 2 : Using an Evidence-Based Research approach before a new study is conducted to ensure value

BACKGROUND AND OBJECTIVES

There is considerable actual and potential waste in research. The aim of this article is to describe how using an evidence-based research approach before conducting a study helps to ensure that the new study truly adds value.

STUDY DESIGN AND SETTING

Evidence-based research is the use of prior research in a systematic and transparent way to inform a new study so that it is answering questions that matter in a valid, efficient, and accessible manner. In this second article of the evidence-based research series, we describe how to apply an evidence-based research approach before starting a new study.

RESULTS

Before a new study is performed, researchers need to provide a solid justification for it using the available scientific knowledge as well as the perspectives of end users. The key method for both is to conduct a systematic review of earlier relevant studies.

CONCLUSION

Describing the ideal process illuminates the challenges and opportunities offered through the suggested evidence-based research approach. A systematic and transparent approach is needed to provide justification for and to optimally design a relevant and necessary new study.

Evidence-Based Research Series-Paper 1: What Evidence-Based Research is and why is it important?

OBJECTIVES

There is considerable actual and potential waste in research. Evidence-based research ensures worthwhile and valuable research. The aim of this series, which this article introduces, is to describe the evidence-based research approach.

STUDY DESIGN AND SETTING

In this first article of a three-article series, we introduce the evidence-based research approach. Evidence-based research is the use of prior research in a systematic and transparent way to inform a new study so that it is answering questions that matter in a valid, efficient, and accessible manner.

RESULTS

We describe evidence-based research and provide an overview of the approach of systematically and transparently using previous research before starting a new study to justify and design the new study (article #2 in series) and-on study completion-place its results in the context with what is already known (article #3 in series).

CONCLUSION

This series introduces evidence-based research as an approach to minimize unnecessary and irrelevant clinical health research that is unscientific, wasteful, and unethical.

Bone-Patellar Tendon-Bone Autografts Versus Hamstring Autografts Using the Same Suspensory Fixations in ACL Reconstruction: A Systematic Review and Meta-analysis

Background:

Bone–patellar tendon–bone (BPB) autografts and hamstring tendon (HT) autografts are 2 popular choices for anterior cruciate ligament reconstruction (ACLR). Although existing meta-analyses have explored the clinical outcomes between BPB and HT autografts, none have based their analysis on studies with just femoral suspensory fixation methods.

Purpose:

To evaluate and compare clinical outcomes, particularly graft failure and knee stability, of ACLR with BPB or HT autografts with suspensory femoral fixation.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A literature search was conducted of studies reporting single-bundle ACLR with BPB autografts and HT autografts with suspensory fixation with a minimum 24-month follow-up. Graft failure rate, knee stability, and clinical outcomes were compared for BPB versus HT autografts. Knee stability was measured with the Lachman test, pivot-shift test, and KT-1000/2000 arthrometer side-to-side difference (SSD). Clinical outcomes were measured with Lysholm scores and the Tegner activity scale, as well as rate of return to preinjury sports. Donor site morbidity among included studies was reviewed. A random-effects model was used for calculations of summary estimates. Subgroup, sensitivity, and trial sequential analyses were conducted.

Results:

Five studies were included. Graft failure was seen more often in the HT group than the BPB group, and this was statistically significant (P = .03). However, the trial sequential analysis outcome indicated that the included sample size was not large enough to support a solid positive finding. The analysis showed no significant difference in SSD, Lachman test, pivot-shift test, rate of return to sports, Lysholm score, or Tegner score between groups. Subgroup analyses found no significant difference between groups.

Conclusion:

This meta-analysis demonstrated no significant differences in knee stability and knee functional outcomes between BPB and HT autografts with suspensory fixation. More evidence is needed to prove the lower risk of failure with use of BTB autograft with suspensory fixation.

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.

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

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

Comparative Study after Hamstring Anterior Cruciate Ligament Reconstruction with Endobutton and Rigidfix: A Clinical Trial Study

Background

One of the most common orthopedic clinic visits involves direct and indirect knee trauma leading to rupture of anterior cruciate ligament (ACL). Endobutton and Rigidfix are most frequent treating methods that used by orthopedic surgeons. Thus the aim of this study was compare the clinical results of reconstructing arthroscopic ACL of the knee through two methods namely Rigidfix and Endobutton.

Materials and Methods

In a clinical trial study, a total of 40 patients with rupture of ACL were selected and randomly divided into two groups. The groups were treated through fixation procedures either Endobutton or Rigidfix. Prior to surgery and then at least 2 years after surgery, the patients were under physical examination in terms of knee range of motion, knee stability, knee pain, ability to perform daily activities and exercises and compared between the two groups.

Results

The knee range of motion in Endobutton and Rigidfix were 135.73 ± 2.63 and 129.87 ± 7.14° resprectively (P = 0.06). comparing two groups, during last month in Endobutton and Rigidfix the frequency of knee pain were 2.5 ± 1.4 and 3.4 ± 1.4 respectively (P = 0.08). Moreover, the pain intensity score were 2.9 ± 1.5 and 2.6 ± 1.1 (P = 0.49). But there was a significant difference observed in patients' satisfaction and ability to perform sports activities.

Conclusions

The two fixation methods namely Endobutton and Rigidfix are not preferred over one another. But patients' satisfaction and ability to perform sports activities in Endobutton was better than the Rigidfix.

Bone-Patellar Tendon-Bone Versus Hamstring Tendon Autografts for Primary Anterior Cruciate Ligament Reconstruction: A Systematic Review of Overlapping Meta-analyses

BACKGROUND

Previous meta-analyses have compared bone-patellar tendon-bone (BPTB) with hamstring tendon (HT) autografts for primary anterior cruciate ligament reconstruction (ACLR).

PURPOSE

To conduct a systematic review of overlapping meta-analyses comparing BPTB with HT autografts for ACLR to determine which meta-analyses provide the best available evidence.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review was performed by searching the PubMed and Cochrane Library databases. Search words included "anterior cruciate ligament" AND "patellar tendon" AND "hamstring tendon" AND "meta-analysis." Results were reviewed to determine study eligibility. Patient outcomes and postoperative complications were extracted from the included meta-analyses. Meta-analysis quality was assessed using the Oxman-Guyatt and Quality of Reporting of Meta-analyses (QUOROM) scores. The Jadad decision algorithm was then utilized to determine which meta-analyses provided the best level of evidence.

RESULTS

Sixteen meta-analyses containing an average of 1396 patients met the eligibility criteria. Most studies found BPTB autografts to provide superior stability but more postoperative complications, such as anterior knee pain and kneeling pain. Studies by Gabler et al (2016), Mohtadi et al (2011), and Xie et al (2015) received the highest Oxman-Guyatt and QUOROM scores, and therefore, these meta-analyses proved to provide the highest level of evidence. Additionally, Xie et al was selected as the highest-quality study in this systematic review based on the Jadad decision algorithm.

CONCLUSION

The current best evidence suggests that ACLR with BPTB autografts provides superior static knee stability and that there are fewer postoperative complications in ACLR with HT autografts.

Graft Diameter as a Predictor for Revision Anterior Cruciate Ligament Reconstruction and KOOS and EQ-5D Values: A Cohort Study From the Swedish National Knee Ligament Register Based on 2240 Patients

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction (ACLR) using a hamstring tendon (HT) autograft is an effective and widespread method. Recent studies have identified a relationship between the graft diameter and revision ACLR.

PURPOSE

To evaluate the influence of the graft diameter on revision ACLR and patient-reported outcomes in patients undergoing primary ACLR using HT autografts.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A prospective cohort study was conducted using the Swedish National Knee Ligament Register (SNKLR) involving all patients undergoing primary ACLR using HT autografts. Patients with graft failure who needed revision surgery (cases) were compared with patients not undergoing revision surgery (controls). The control group was matched for sex, age, and graft fixation method in a 3:1 ratio. Conditional logistic regression was performed to produce odds ratios and 95% CIs. Univariate linear regression analyses were performed for patient-related outcomes. The Knee injury and Osteoarthritis Outcome Score (KOOS) and EuroQol 5 dimensions questionnaire (EQ-5D) values were obtained.

RESULTS

A total of 2240 patients were included in which there were 560 cases and 1680 controls. No significant differences between the cases and controls were found for sex (52.9% male), mean age (21.7 years), and femoral and tibial fixation. The mean graft diameter for the cases was 8.0 ± 0.74 mm and for the controls was 8.1 ± 0.76 mm. In the present cohort, the likelihood of revision surgery for every 0.5-mm increase in the HT autograft diameter between 7.0 and 10.0 mm was 0.86 (95% CI, 0.75-0.99; P = .03). Univariate linear regression analysis found no significant regression coefficient for the change in KOOS or EQ-5D values.

CONCLUSION

In a large cohort of patients after primary ACLR with HT autografts, an increase in the graft diameter between 7.0 and 10.0 mm resulted in a 0.86 times lower likelihood of revision surgery with every 0.5-mm increase. This study provides further evidence of the importance of the HT autograft size in intraoperative decision making.

Autograft Options for ACL Reconstruction. Which is Best?

Anterior cruciate ligament (ACL) tears are commonly seen in orthopedic practice, and usually restoration is recommended to re-establish normal knee function. Autografts and allografts are viable options. Among autografts the main sources are the patellar tendon, the hamstrings and the quadriceps tendon, each having advantages and drawbacks. Many factors should be taken into consideration when deciding on a graft source for ACL restoration; however, clinical data may aid the surgeon in choosing the right graft for every specific patient in an individualized manner. This short review is intended to highlight the main characteristics and clinical data for each type of autograft.

Bone tunnel enlargement following hamstring anterior cruciate ligament reconstruction: a comprehensive review

Nowadays, bone tunnel enlargement (BTE) after anterior cruciate ligament reconstruction is a well-known phenomenon. It has been identified, investigated and described by many authors during the last thirty years. Nevertheless, the etiology of bone tunnel enlargement still remains unclear. It is known that the causes are multifactorial and may include the surgical technique, the method of fixation, materials used, type of graft as well as biological factors. Due to the recent popularization of the use of hamstring grafts in anterior cruciate ligament reconstruction, the bone tunnel enlargement phenomenon is becoming increasingly common. In this review article, the authors focus on compiling current knowledge about the etiology, diagnosis, and the possibility of reducing the occurrence of this phenomenon by using the latest methods of supporting reconstruction surgery.

Credibility and quality of meta-analyses addressing graft choice in anterior cruciate ligament reconstruction: a systematic review

PURPOSE

This systematic review examined the methodological credibility and quality of reporting of all meta-analyses which have compared bone-patellar tendon-bone (BPTB) versus hamstring tendon (HT) for anterior cruciate ligament (ACL) reconstruction (ACLR).

METHODS

EMBASE, MEDLINE, and The Cochrane Library were systematically searched, and two reviewers independently assessed eligibility, credibility according to the Users' Guide to medical literature, and completeness of reporting according to the preferred reporting items for systematic review and meta-analyses (PRISMA) checklist. Inter-rater agreement was quantified using Kappa, and we used Pearson's correlation coefficient to evaluate potential associations.

RESULTS

Seventeen meta-analyses were identified comparing BPTB versus HT for ACLR. The majority of meta-analyses were published in 2011 (5; 29 %), and North America was the most common continent of publication (6; 35 %). The three most commonly reported outcomes were stability (82 %), complications (76 %), and function (return to sport, IKDC score) (71 %). The median number of satisfactorily reported items in the Users' Guide was three out of seven (IQR 2-4). The median number of satisfactorily reported items in PRISMA for the meta-analyses was 20 out of 27 (IQR 19-22).

CONCLUSION

The credibility of the meta-analyses comparing BPTB versus HT autograft for ACLR although limited is improving with time. Earlier studies had limited methodological rigour; however, the more recent studies have shown promise in improved methodology. The study findings suggest that decisions should be made on a case-to-case basis with coordination of patient factors and preferences as well as surgeon experience on the background of the best available evidence.

LEVEL OF EVIDENCE

IV.

Tibial fixation in anterior cruciate ligament reconstruction

OBJECTIVE

To determine whether supplementary tibial graft fixation with a staple is routinely necessary for anterior cruciate ligament (ACL) reconstructions.

METHODS

We retrospectively reviewed a series of consecutive patients who underwent ACL reconstruction at our institution from April 2012 to July 2013. Patients who fulfilled the inclusion and exclusion criteria were divided into two groups, of which one with tibial fixation of the graft with a biointerference screw alone (biointerference screw group) and the other with tibial fixation of the graft with a biointerference screw and supplementary extra tunnel staple fixation (biointerference screw and staple group). All the surgeries were performed by a single fellowship-trained sports surgeon, using a standardized transportal technique and rehabilitation protocol. Both well-matched groups were evaluated at 1-year follow-up objectively for ligament laxity using instrumented testing with KT-2000 arthrometer and clinical tests as well as subjectively with the validated International Knee Documentation Committee 2000 (IKDC) and Lysholm knee score. All complications were reported.

RESULTS

A total of 64 patients (31 in the only biointerference screw group and 33 in the biointerference screw and staple group) were included in the study. At 1 year, there was no significant difference in the objective and subjective outcome assessments between the two groups. However, four patients from the group with supplementary staple experienced symptomatic hardware on kneeling of which two necessitated removal of hardware.

CONCLUSION

Our study showed that supplementary tibial graft fixation with a staple is not routinely necessary for ACL reconstructions. It confers no additional benefits when compared with the use of biointerference screw alone for tibial graft fixation but may increase the risks of symptomatic hardware.

Electrospun silk fibroin mat enhances tendon-bone healing in a rabbit extra-articular model

OBJECTIVE

To investigate whether electrospun silk fibroin (SF) mat wrapping could enhance tendon-bone healing of soft tissue graft.

RESULTS

Rabbit bone marrow-derived mesenchymal stem cells proliferated well on electrospun SF mat. The autologous Achilles tendon wrapped with electrospun SF mat was transplanted into the bone tunnel (experimental group) in a rabbit extra-articular model, while the unwrapped tendon was transplanted as control group. The electrospun SF mat wrapping could enhance tendon-bone healing of autologous tendon evaluated by micro-computed tomography scanning, histological examination and mechanical testing. At 6 and 12 weeks post-operatively, the failure loads of experimental group were both significantly higher than those of control group (40.5 ± 6.3 vs. 31.8 ± 4.6 N, P = 0.039 at 6 weeks; 67.1 ± 9. vs. 52.2 ± 4.7 N, P = 0.012 at 12 weeks).

CONCLUSION

The electrospun SF mat wrapping could enhance tendon-bone healing of soft tissue graft.

The Effect of Autologous Hamstring Graft Diameter on the Likelihood for Revision of Anterior Cruciate Ligament Reconstruction

BACKGROUND

Hamstring autografts for anterior cruciate ligament (ACL) reconstruction (ACLR) have become popular in the past 2 decades; however, it is difficult to predict the diameter of the harvested tendons before surgery. Previous biomechanical studies have suggested that a smaller graft diameter leads to a lower load to failure, but clinical studies looking at various predictors for failure, including graft size, have been inconclusive.

PURPOSE

To evaluate the relationship of hamstring graft diameter to ACL revision within a large cohort of patients, while controlling for sex, age, body mass index (BMI), and femoral and tibial fixation type.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A case-control study using patients registered in an ACLR registry was conducted. Revision was used as a marker for graft failure. A case was defined as a patient who underwent primary ACLR with a hamstring autograft that was revised during the study period (April 2006 to September 2012). Three controls, defined as patients who underwent primary ACLR with a hamstring autograft that was not revised, were matched to each of the cases according to age, sex, BMI, and femoral and tibial fixation type. Descriptive characteristics were employed, and conditional logistic regression was conducted to produce estimates of odds ratios and 95% CIs.

RESULTS

A total of 124 cases and 367 controls were identified. There were no significant differences between cases and controls in the distribution of sex (52.4% male vs 52.9% male, respectively; P = .932), median age (17.6 years [interquartile range (IQR), 15.9-20.4] vs 17.6 years [IQR, 15.9-20.4], respectively; P = .999), median BMI (23.4 kg/m(2) [IQR, 21.5-26.4] vs 23.4 kg/m(2) [IQR, 21.6-25.8], respectively; P = .954), femoral fixation (P = .459), and tibial fixation (P = .766). The mean (±SD) graft diameter was 7.9 ± 0.75 mm in the cases and 8.1 ± 0.73 mm in the controls. The likelihood of a patient needing revision ACLR in the study cohort was 0.82 times lower (95% CI, 0.68-0.98) for every 0.5-mm increase in the graft diameter from 7.0 to 9.0 mm.

CONCLUSION

In this study, within the range of 7.0 to 9.0 mm, there was a 0.82 times lower likelihood of being a revision case with every 0.5-mm incremental increase in graft diameter.

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

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

RESULTS

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

CONCLUSION

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

A meta-analysis of bone-patellar tendon-bone autograft versus four-strand hamstring tendon autograft for anterior cruciate ligament reconstruction

BACKGROUND

There is a lack of comprehensive studies comparing the clinical outcome of anterior cruciate ligament (ACL) reconstruction with either a bone-patellar tendon-bone (BPTB) or four-strand hamstring tendon (4SHT) autografts. The optimal choice of graft for anterior cruciate ligament reconstruction remains controversial.

PURPOSE

The objective of this study was to evaluate the effectiveness of BPTB autografts versus 4SHT autografts for the reconstruction of ACL.

METHODS

A systematical search of literature was performed in Pubmed, Embase, and the Cochrane library to identify published clinical prospective studies relevant to ACL reconstruction comparing BPTB and 4SHT autografts. The results of the eligible studies were analysed in terms of instrumented laxity measurements, Lachman test, pivot shift test, objective International Knee Documentation Committee (IKDC) scores, return to preinjury activity level, and morbidity of graft failure, anterior knee pain, kneeling pain, extension deficit, and flexion deficit. Study quality was assessed by using the Jadad scale for randomized clinical trial (RCT) and the Newcastle-Ottawa Scale (NOS) for prospective cohort study (PCS). Two reviewers independently assessed each study for quality and extracted data. Subgroup analysis of the primary outcomes was conducted according to the type of study design (RCT or PCS).

RESULTS

Twenty-two studies, with 931 patients in the BPTB group and 999 patients in the 4SHT group, met the inclusion criteria. Fourteen studies were randomized controlled trials, and eight were prospective cohort studies. The results of the meta-analysis showed that there were no significant differences between BPTB and 4SHT in terms of instrumented laxity measurements (P=0.06), Lachman test (P=0.58), objective IKDC scores (P=0.31), graft failure (P=0.45), extension deficit (P=0.06) and flexion deficit (P=0.63). However, outcomes in favour of BPTB were found in terms of pivot shift test (P=0.01) and return to preinjury activity level (P=0.03); outcome measures that favours 4SHT included anterior knee pain (P<0.01) and kneeling pain (P<0.01). These findings were still robust during the sensitivity analysis. Results from subgroup analysis of the primary outcomes were consistent with the overall analysis.

CONCLUSION

Based on the results above, ACL reconstruction with BPTB autografts might be superior in resuming rotation stability of the knee joint and allow patients to return to higher levels of activity in comparison with 4SHT autografts. Whereas, postoperative complications of the knee joint were lower for 4SHT autografts than for BPTB autografts. There was insufficient evidence to identify which of the two types of grafts was significantly better for ACL reconstruction considering the limitations of this study. More high-quality randomized controlled trials with strictly specified inclusion criteria are highly required before drawing a reliable conclusion.

Accumulating research: a systematic account of how cumulative meta-analyses would have provided knowledge, improved health, reduced harm and saved resources

Background

“Cumulative meta-analysis” describes a statistical procedure to calculate, retrospectively, summary estimates from the results of similar trials every time the results of a further trial in the series had become available. In the early 1990s, comparisons of cumulative meta-analyses of treatments for myocardial infarction with advice promulgated through medical textbooks showed that research had continued long after robust estimates of treatment effects had accumulated, and that medical textbooks had overlooked strong, existing evidence from trials. Cumulative meta-analyses have subsequently been used to assess what could have been known had new studies been informed by systematic reviews of relevant existing evidence and how waste might have been reduced.

Methods and Findings

We used a systematic approach to identify and summarise the findings of cumulative meta-analyses of studies of the effects of clinical interventions, published from 1992 to 2012. Searches were done of PubMed, MEDLINE, EMBASE, the Cochrane Methodology Register and Science Citation Index. A total of 50 eligible reports were identified, including more than 1,500 cumulative meta-analyses. A variety of themes are illustrated with specific examples. The studies showed that initially positive results became null or negative in meta-analyses as more trials were done; that early null or negative results were over-turned; that stable results (beneficial, harmful and neutral) would have been seen had a meta-analysis been done before the new trial; and that additional trials had been much too small to resolve the remaining uncertainties.

Conclusions

This large, unique collection of cumulative meta-analyses highlights how a review of the existing evidence might have helped researchers, practitioners, patients and funders make more informed decisions and choices about new trials over decades of research. This would have led to earlier uptake of effective interventions in practice, less exposure of trial participants to less effective treatments, and reduced waste resulting from unjustified research.

Can technology improve alignment during knee arthroplasty

Component malalignment remains a concern in total knee arthroplasty (TKA); therefore, a series of technologies have been developed to improve alignment. The authors conducted a systematic review to compare computer-assisted navigation with conventional instrumentation, and assess the current evidence for patient-matched instrumentation and robot-assisted implantation. An extensive search of the PubMed database for relevant meta-analyses, systematic reviews and original articles was performed, with each study scrutinised by two reviewers. Data on study characteristics and outcomes were extracted from each study and compared. In total 30 studies were included: 10 meta-analyses comparing computer-assisted navigation and conventional instrumentation, 13 studies examining patient-matched instrumentation, and seven investigating robot-assisted implantation. Computer-assisted navigation showed significant and reproducible improvements in mechanical alignment over conventional instrumentation. Patient-matched instrumentation appeared to achieve a high degree of mechanical alignment, although the majority of studies were of poor quality. The data for robot-assisted surgery was less indicative. Computer-assisted navigation improves alignment during TKA over conventional instrumentation. For patient-matched instrumentation and robot-assisted implantation, alignment benefits have not been reliably demonstrated. For all three technologies, clinical benefits cannot currently be assumed, and further studies are required. Although current technologies to improve alignment during TKA appear to result in intra-operative benefits, their clinical impact remains unclear, and surgeons should take this into account when considering their adoption.

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.

Effectiveness of anterior cruciate ligament injury prevention training programs

BACKGROUND

The objective of this study was to systematically review the literature on anterior cruciate ligament (ACL) injury prevention programs and to perform a meta-analysis to address three questions: First, what is the effectiveness of ACL injury prevention programs? Second, is there evidence for a "best" program? Third, what is the quality of the current literature on ACL injury prevention?

METHODS

We conducted a systematic review with use of the online PubMed, MEDLINE, EMBASE, CINAHL (Cumulative Index to Nursing and Allied Health), and Cochrane Central Register of Controlled Trials databases. Search terms were anterior cruciate ligament, knee, injury, prevention, and control. Data on study design and clinical outcomes were extracted independently in triplicate. After assessment of between-study heterogeneity, DerSimonian-Laird random-effect models were used to calculate pooled risk ratios and risk differences. The risk difference was used to estimate the number needed to treat (the number of individuals who would need to be treated to avoid one ACL tear).

RESULTS

The pooled risk ratio was 0.38 (95% confidence interval [CI], 0.20 to 0.72), reflecting a significant reduction in the risk of ACL rupture in the prevention group (p = 0.003). The number needed to treat ranged from five to 187 in the individual studies. Stratified by sex, the pooled risk ratio was 0.48 (95% CI, 0.26 to 0.89) for female athletes and 0.15 (95% CI, 0.08 to 0.28) for male athletes.

CONCLUSIONS

Our study indicated strong evidence in support of a significant effect of ACL injury prevention programs. Our pooled estimates suggest a substantial beneficial effect of ACL injury prevention programs, with a risk reduction of 52% in the female athletes and 85% in the male athletes.

A cost-effectiveness analysis comparing 3 anterior cruciate ligament graft types: bone-patellar tendon-bone autograft, hamstring autograft, and allograft

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction, despite being one of the most common surgical interventions, is also one of the least agreed upon surgeries when it comes to optimum graft choice. Three graft choices stand among the most widely used in this procedure: (1) bone-patellar tendon-bone autograft (BPTB), (2) quadruple hamstring tendon autograft (HS), and (3) allograft.

HYPOTHESIS

Bone-patellar tendon-bone ACL reconstruction is the most cost-effective method of ACL reconstruction.

STUDY DESIGN

Economic and decision analysis; Level of evidence, 2.

METHODS

A simplified decision tree model was created with theoretical patients assigned equally to 1 of 3 ACL reconstruction cohorts based on graft type. These treatment arms were further divided into outcome arms based on probabilities from the literature. The terminal outcomes were assigned a health state/utility score and a societal cost. Utilities were calculated from real clinic patients via the time trade-off questionnaire. Costs were literature based. An incremental cost-effectiveness ratio of $50 000/quality-adjusted life year (QALY) was used as the threshold for cost-effectiveness.

RESULTS

Hamstring tendon autograft was the least costly ($5375/surgery) and most effective (0.912) graft choice, dominating both BPTB and allograft reconstructions. Allograft was both the most costly and least effective strategy for the average patient undergoing ACL reconstruction. However, if baseline costs of BPTB could be reduced (by $500) or the effectiveness increased (anterior knee pain <15% or postoperative instability <7%), then BPTB became an incrementally cost-effective choice. In addition, if the effectiveness of HS could be reduced (instability >29% or revision rates >7%), then BPTB also became incrementally cost-effective.

CONCLUSIONS

This model suggests that hamstring autograft ACL reconstruction is the most cost-effective method of surgery for the average patient with ACL deficiency. However, specific clinical scenarios that change postoperative probabilities of the different complications may sway surgeons to choose either allografts or BPTB. Cost-effectiveness analysis is not intended to replace individual clinician judgment but rather is intended to examine both the effectiveness and costs associated with theoretical groups undergoing specific multifactorial decisions.

Arthrofibrosis after anterior cruciate ligament reconstruction in children and adolescents

INTRODUCTION

Arthrofibrosis is a known complication after anterior cruciate ligament (ACL) reconstruction. ACL reconstruction is being performed with increased frequency in the pediatric population. The purpose of this study was to determine the prevalence of arthrofibrosis in children and adolescents and to identify risk factors for arthrofibrosis.

METHODS

The study design was a retrospective case series. Medical records for 1016 consecutive ACL reconstructions in patients aged 7 to 18 years old between 1995 to 2008 at a major tertiary care children's hospital were reviewed to identify cases of postoperative arthrofibrosis. Arthrofibrosis was defined as a loss of 5 degrees or more extension compared with the contralateral knee that required a follow-up procedure or a loss of 15 degrees or more flexion compared with the contralateral knee that required a follow-up procedure. Patient data were recorded and analyzed using bivariate models to identify predictors for arthrofibrosis. Further, we reviewed the clinical course of patients with treated arthrofibrosis to assess functional outcomes of this complication.

RESULTS

Nine hundred two patients with 933 knees met the inclusion criteria for this study, of which 60% were female. The mean age at the time of surgery was 15 years (range, 7 to 18 y), and the average follow-up from original ACL reconstruction was 6.3 years (range, 1.6 to 14.2 y). The overall prevalence of arthrofibrosis in our cohort was 8.3%, with 77 of the 933 knees had at least 1 procedure to treat arthrofibrosis after ACL reconstruction. Risk factors for arthrofibrosis were female sex (11.1% females, P = 0.0001), patients aged 16 to 18 years [11.6%; odds ratio (OR) 3.51; P = 0 .007], patellar tendon autograft (OR, 1.7; P = 0.026), and concomitant meniscal repair (OR, 2.08; P = 0.007). Prior knee surgery and ACL reconstruction within 1 month of injury were not significantly associated with arthrofibrosis after ACL reconstruction. Fifty-three patients had a minimum of 6 months clinical follow-up after the procedure for arthrofibrosis. Of these, 46 patients (86.8%) had full range of motion at follow-up. Thirty-two patients (60.4%) were asymptomatic at final follow-up. Eleven patients (20.8%) complained of some persistent pain.

CONCLUSIONS

The rate of arthrofibrosis after ACL reconstruction in children and adolescents is 8.3%. Risk factors for arthrofibrosis are female sex, older adolescents, concurrent meniscal repair, and reconstruction with patellar tendon autograft. Surgical treatment for arthrofibrosis after ACL reconstruction in pediatric patients can satisfactorily regain motion in the reconstructed knee; however functional outcome may be compromised.

LEVEL OF EVIDENCE

Level 4.

A meta-analysis of hamstring autografts versus bone-patellar tendon-bone autografts for reconstruction of the anterior cruciate ligament

The objective of this study was to evaluate the effectiveness of hamstring (HT) autografts versus bone-patellar tendon-bone (BPTB) autografts for reconstruction of the anterior cruciate ligament (ACL). We searched the Cochrane Library, MEDLINE, EMBASE and the Chinese Biomedicine Database (CBM) for published randomised clinical trials (RCTs) relevant to ACL reconstruction comparing HT and BPTB autografts. Data analyses were performed with Cochrane Collaboration's RevMan 5.0. A total of 23 reports of 19 randomised controlled trials (RCTs) (1643 patients) met the inclusion criteria. Outcomes favouring BPTB autografts were found in terms of KT-1000 arithmometer values, negative rates of Lachman tests and negative rates of Pivot tests. Outcome measures that favoured HT autografts included anterior knee pain, kneeling pain and extension loss. There was no statistical difference of postoperative graft failure. Overall, postoperative complications of the knee joint were lower for HT autografts than for BPTB autografts, and BPTB autografts were superior to HT autografts in resuming stability of the knee joint, but four-strand HT combined with application of the modern endobutton HT graft-fixation technique could increase knee-joint stability.

Tibial fixation in anterior cruciate ligament reconstruction: a prospective randomized study comparing metal interference screw and staples with a centrally placed polyethylene screw and sheath

BACKGROUND

The use of hamstring tendons for anterior cruciate ligament reconstruction has increased in popularity over recent years. However, concerns with the stability of graft fixation on the tibial side remain. Centrally placed interference screw/sheath implants have demonstrated promising results in biomechanical studies.

HYPOTHESIS

Centrally placed, polyethylene screw and sheath implants will provide clinically equivalent fixation to the standard metal interference screw and supplemental staple fixation.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 113 consecutive patients undergoing isolated, unilateral, primary anterior cruciate ligament reconstruction with hamstring autografts were randomized to tibial fixation with metal interference screw and staples (RCI) or with a centrally placed polyethylene screw and sheath implant (INTRAFIX). Prospective assessment of subjective outcomes was performed using Lysholm, Mohtadi, and International Knee Documentation Committee (IKDC) scores.

RESULTS

At minimum 2-year follow-up, there were no significant differences between the 2 groups in terms of instrumented stability testing (KT-1000 arthrometer) or subjective assessment of knee outcomes (IKDC, Lysholm, Mohtadi). Both fixation methods demonstrated a significant, but not different, increase in outcomes scores from preoperative to postoperative evaluation. There were 7 failures (5 INTRAFIX, 2 RCI) caused by reinjury, but no statistically significant differences were observed between the 2 fixation methods.

CONCLUSION

The centrally placed polyethylene screw and sheath provided equivalent clinical outcomes at minimum 2-year follow-up to standard tibial fixation with metal interference screw and staples.

Single-bundle patellar tendon versus non-anatomical double-bundle hamstrings ACL reconstruction: a prospective randomized study at 8-year minimum follow-up

PURPOSE

The purpose of this study was to compare subjective, objective and radiographic outcome of the lateralized single-bundle bone-patellar tendon-bone autograft with a non-anatomical double-bundle hamstring tendons autograft anterior cruciate ligament (ACL) reconstruction technique at long-term follow-up.

METHODS

Seventy-nine non-consecutive randomized patients (42 men; 37 women) with unilateral ACL insufficiency were prospectively evaluated, before and after ACL reconstruction by means of the above-mentioned techniques, with a minimum follow-up of 8 years (range 8-10 years; mean 8.6 years). In the double-bundle hamstrings technique, we used one tibial and one femoral tunnel combined with one "over-the-top" passage, cortical staple's fixation and we left intact hamstrings' tibial insertion. Patients were evaluated subjectively and objectively, using IKDC score, Tegner level, manual maximum displacement test with KT-2000™ arthrometer. Radiographic evaluation was performed according to IKDC grading system, and re-intervention rate for meniscal lesions was also recorded.

RESULTS

The subjective and objective IKDC were similar in both groups while double-bundle hamstrings group showed significantly higher Tegner level (P = 0.0007), higher passive range of motion recovery (P = 0.0014), faster sport resumption (P = 0.0052), lower glide pivot-shift phenomenon (P = 0.0302) and lower re-intervention rate (P = 0.0116) compared with patellar tendon group. Radiographic evaluation showed significant lower objective degenerative changes in double-bundle hamstrings group at final follow-up (P = 0.0056).

CONCLUSION

Although both techniques provide satisfactory results, double-bundle ACL reconstruction shows better functional results, with a faster return to sport activity, a lower re-operation rate and lower degenerative knee changes.

Analysis of return to competition and repeat rupture for 298 anterior cruciate ligament reconstructions with patellar or hamstring tendon autograft in sportspeople

OBJECTIVES

To establish the influence of the type of surgical technique, competitive level, type of sport and the time before returning to competition on the reinjury rate after anterior cruciate ligament (ACL) surgery.

METHODS

The authors followed-up 540 competitive sportspeople who had undergone ACL surgery via patellar or hamstring tendon autograft (HTA) techniques in 2003 and 2004. The sportspeople (all of whom had competed at a regional or higher level) were asked to fill out a questionnaire during their fourth postoperative year.

RESULTS

The 298 respondees (reply rate: 55.1%) had the same characteristics as the initial (operated) population. The reinjury rates after HTA and patellar tendon autograft (PTA) were 12.7 and 6.1%, respectively. There was no statistically significant difference between these two values (P=0.14). Age and gender were not correlated with the frequency of reinjury. The reinjury rate rose slightly with increasing competitive level (regional level: 8.1%; national level: 10.4%; international level: 12.5%) but these differences were not statistically significant. Soccer had the highest reinjury rate (20.8%). Regardless of the surgical technique, sportspeople returning to competition within seven months of surgery had a greater risk of reinjury than those returning after this time point (15.3 versus 5.2%, P=0.014). The risk dropped from 13.9 to 2.6% (P=0.047) for PTA and from 16.6 to 7.6% (P=0.2) for HTA. Of the four reinjuries in sportspeople returning to competition with the first six months postoperative, three occurred within one month of resumption.

CONCLUSION

Post-HTA reinjury rates are higher than post-PTA rates but the difference is not statistically significant. For sportspeople at a regional or higher level, the time interval before the return to competition has an influence on the risk of reinjury.

Autologous patellar tendon and quadrupled hamstring grafts in anterior cruciate ligament reconstruction: a prospective randomized multicenter review of different fixation methods

ACL reconstruction with bone patellar tendon bone (BPTB) grafts has been shown to produce dependable results. Recently, reconstructions with double-looped semitendinosus gracilis (DLSG) grafts have become common. The prevailing opinion is that ACL reconstruction with patellar tendon graft produces a more stable knee with more anterior knee pain than DLSG grafts, while the functional results and knee scores are similar. The present study evaluates BPTB grafts fixed with metallic interference screws and DLSG grafts fixed with Bone Mulch Screw on the femur and WasherLoc fixation on the tibia. All else being the same, there is no difference in the outcome between the two grafts and fixation methods. This is a prospective randomized multicenter study. A total of 115 patients with isolated ACL ruptures were randomized to either reconstruction with BPTB grafts fixed with metal interference screws (58 patients) or DLSG grafts (57 patients) fixed with Bone Mulch Screws and WasherLoc Screws. Follow-up was at one and two years; the latter by an independent observer. At two years, one ACL revision had been performed in each group. Eight patients in the DLSG group and one in the BPTB group underwent meniscus surgery in the follow-up period (P = 0.014). Mean Lysholm score at the two year follow-up was 91 (SD +/- 10.3) in the DLSG group and also 91 (SD +/- 10.2) in the BPTB group. Mean KT-1000 at two years was 1.5 mm in the BPTB group and 1.8 mm in the DLSG group (n.s.). At two years, four patients in the BPTB group and three in the DLSG group had a Lachman test grade 2 or 3 (n.s.). More patients in the BPTB group had pain at the lower pole of the patella (P = 0.04). Peak flexion torque and total flexion work were lower in the DLSG group at one year (P = 0.003 and P = 0.000) and total flexion work also at two years (P = 0.05). BPTB ACL reconstruction fixed with interference screws and DLSG fixed with Bone Mulch Screws on the femur and WasherLoc Screws on the tibia produce satisfactory and nearly identical outcomes. Among our patients in the DLSG group, flexion strength was lower, and more patients underwent meniscus surgery in the follow-up period. The BPTB group has more anterior knee pain.

Translational studies in anterior cruciate ligament repair

Translational research, which can be explained as the principle of combining advances in both basic research and clinical understanding in a bedside-to-bench-to-bedside approach, has become one of the central themes of present-day medical research. One orthopedic problem that has strongly benefited from such an approach is tissue-engineering-enhanced primary repair of the anterior cruciate ligament. Recent years have shown a clearer definition of the clinical problem and established an underlying mechanistic cause of the incapacity of the anterior cruciate ligament to heal-the premature loss of provisional scaffold in the wound site. These clinical findings were then translated into a research objective, namely, to replace the missing scaffold with a biomaterial with appropriate structural and bio-stimulatory characteristics. Subsequently, a tissue-engineering-based treatment using a collagen-platelet composite was developed and tested in vitro. After proofing the efficacy of this new treatment in the laboratory, it was translated into a potential clinical application, which showed highly successful results in structural integrity and biomechanical capacity in large animal testing. This approach of defining the scientific mechanism underlying a clinical observation and then using that information to design new therapies is but one example of how translational research in tissue engineering can help define and develop new treatments for challenging problems faced by patients.

Anatomy of normal human anterior cruciate ligament attachments evaluated by divided small bundles

BACKGROUND

Double-bundle anterior cruciate ligament (ACL) reconstruction has several potential advantages over single-bundle reconstruction with hamstring tendons. However, there are still controversies regarding tunnel placement in tibial and femoral attachments.

HYPOTHESIS

The macroscopically normal ACL consists of small bundles about 1 mm in diameter. Detailed observation of the divided smaller bundles will achieve better understanding of the tunnel placement in anatomic ACL reconstruction.

STUDY DESIGN

Descriptive laboratory study.

METHODS

This study used 20 cadaveric knees. The ACL was divided into anteromedial and posterolateral bundles, then separated into 10 small bundles of 2-mm diameters, with preservation of their attachment sites marked with color markers. The positional relationship between the femoral and tibial attachments of each small bundle was investigated.

RESULTS

A layered positional correlation of small bundles was found between the tibial and femoral attachments. Small bundles aligned in the anterior-posterior direction in the tibia corresponded to the bundles aligned in a high-low direction in the femur in flexion. The femoral attachment pattern was relatively similar in each specimen; however, the tibial attachment showed 2 patterns: an oblique type (12 of 20) and a transverse type (8 of 20). The posterior portion of the posterolateral bundle was separately attached to the medial and lateral portions of the tibial attachment. There was no fibrous insertion in the center of the posterior portion of the ACL tibial attachment in any specimen. In this bare area, there was fat tissue and vascular bundles.

CONCLUSION

Small bundles constituting the ACL showed a relatively layered arrangement between 2 attachments. The tibial attachment showed 2 patterns of oblique and transverse types, and the vascular bundles were located in the center of the posterolateral bundle.

CLINICAL RELEVANCE

The results of this study of the normal ACL will provide insights for surgeons when placing grafts during anatomic ACL reconstruction.

Anterior cruciate ligament reconstruction: assessment of the hamstring autograft femoral fixation using the EndoButton CL

The objective of this study was to evaluate the clinical and radiological results of a prospective, continuous series of 105 ACL reconstructions using the STG tendons fixed to the femur by an EndoButton CL, with more than 4 years of follow-up.

HYPOTHESIS

The subjective and objective clinical results as well as the radiological results (tunnel enlargement) obtained by a cortical, extra-anatomic femoral fixation are at least equivalent to the results obtained with other types of femoral fixation systems.

MATERIAL AND METHODS

One hundred and five patients aged with a mean 26 years (range, 12-56 years) were operated on for an anterior cruciate ligament rupture using the same technique and by the same operator: four-strand STG fixed to the tibia by a double fixation--BioRCI-HA screw and staple--and on the femur by an EndoButton CL (Smith and Nephew). The results were assessed at 6 months, 1 and 2 years and then at a mean follow-up of 51 months, both clinically (IKDC, Lysholm, KT-1000) and radiologically (Telos laximetry, tunnel position, and morphological analysis).

RESULTS

No complications related to the use of the EndoButton were observed. No additional interference screw was necessary. According to the IKDC laxity classification, 91.4% of the patients were classified in category A or B, nine knees (8.6%) were classified C or D. Four failures required revision with a patellar tendon graft. On the final IKDC score, 63 patients (60%) were classified grade A, 37 grade B (35.3%), four grade C (3.8%), and one grade D (0.9%). On the Telos laximetry, 62 patients (59%) had a differential laxity less than or equal to 2 mm. The mean value was 1.8 mm (range, 0-11). Tibial tunnel enlargement was constant; femoral tunnel enlargement was significant (>2 mm) in 27.6% of the knees. No femoral tunnel diameter modification corresponding to the EndoButton passage was observed.

DISCUSSION

The results of this series are comparable to the results of other series. Its reproducibility and the absence of iatrogenic complications for this femoral EndoButton CL fixation make it a top-choice technique, like the corticocancellous graft procedures, but without their disadvantages. No secondary elongation attributable to the EndoButton CL was observed. This femoral fixation procedure appeared necessary and sufficient to providing good mechanical stability for the graft in the femoral tunnel.

A systematic review of conflicting meta-analyses in orthopaedic surgery

Meta-analyses are important evaluations in orthopaedic surgery, not only to create clinical guidelines, but also because their findings are included in public health and health policy decision making. However, with increasing numbers of meta-analyses, discordant and frankly conflicting conclusions have been reported. We searched for conflicting meta-analyses, ie, those arriving at different conclusions despite following the same research question, identified potential reasons for these differences, and assessed the statistical significance and clinical importance of differences. We identified conflicting meta-analyses on graft choice in ACL reconstruction and the use of hyaluronic acid. We found significant differences in individual results only for meta-analyses on hyaluronic acid, but the 95% confidence intervals of the magnitude of differences included values as much as 40% for ACL meta-analyses. However, our findings suggest most conflicts derive from differences in the interpretation of pooled results rather than in the actual results. Thus conclusions and interpretations from meta-analyses should be scrutinized as critically as those from any other type of study and subjected to reassessment if deemed necessary.

Anterior cruciate ligament reconstruction: autogenous quadriceps tendon-bone compared with bone-patellar tendon-bone grafts at 2-year follow-up

PURPOSE

The purpose of this study was to evaluate and compare postoperative anterior knee pain, knee stability, and functional scores of an autogenous bone-patellar tendon-bone (BPTB) graft and a quadriceps tendon-bone (QTB) graft.

METHODS

A total of 48 patients--27 who had anterior cruciate ligament (ACL) reconstruction by use of an autogenous BPTB graft and 21 who had ACL reconstruction by use of a QTB graft--were assessed at a minimum follow-up of 24 months after surgery. An accelerated rehabilitation program was adapted, and the rehabilitation protocol was identical for both groups.

RESULTS

The mean side-to-side difference as measured with a KT-2000 arthrometer (MEDmetric, San Diego, CA) was 2.73 mm (SD, 1.45 mm) in the BPTB group and 2.79 mm (SD, 1.32 mm) in the QTB group (P = .880). Postoperatively, the International Knee Documentation Committee score was grade A or B in 23 patients (85.2%) in the BPTB group and 18 (85.7%) in the QTB group (P = .997). The mean anterior knee pain score was 86.9 in the BPTB group as compared with 90.2 in the QTB group (P = .107). In a kneeling posture, 13 BPTB patients reported discomfort (moderate in 10 and severe in 3) whereas only 4 QTB patients had moderate discomfort (P = .029). No significant differences were found with regard to other activities surveyed.

CONCLUSIONS

A QTB graft attached with the EndoPearl device (Linvatec, Largo, FL) appears to be an effective alternative for single-bundle ACL reconstruction. When followed with an accelerated rehabilitation program, reconstruction with a QTB graft provided knee stability comparable to a BPTB graft but with less kneeling pain than a BPTB graft.

No difference in clinical results between femoral transfixation and bio-interference screw fixation in hamstring tendon ACL reconstruction. A preliminary study

Hamstring tendon autograft has become a popular graft choice for anterior cruciate ligament (ACL) reconstruction, but there is no consensus on the ideal technique of fixation. We performed a pilot randomized controlled study to compare the clinical and mechanical outcome of two femoral fixation techniques for anterior cruciate ligament (ACL) reconstruction using hamstrings graft. We recruited 30 patients with a chronic unilateral tear of the anterior cruciate ligament. In all patients, quadrupled hamstring graft was used for ACL reconstruction. In 15 patients, femoral graft fixation was performed using Bio-interference Screws fixation (Arthrex, Inc. Naples USA) (Group 1). In the other 15 patients, femoral graft fixation was performed using BioTransFix femur extra cortical transverse fixation (Arthrex, Inc. Naples USA) (Group 2). In both groups, tibial fixation was achieved with a Delta bio-absorbable interference screw (Arthrex). Both groups were comparable with regard to demographic data, pre-operative activity level, mechanism of injury, interval between the injury and the operation, and pre-operative knee laxity measurements. An independent observer, who was blinded with regard to the involved leg and the type of graft, performed the outcome assessment with the use of a Rolimeter arthrometer (Aircast), and the International Knee Documentation Committee. At 13 months follow up, all patients except one had functionally normal or nearly normal IKDC objective scores. The mean IKDC subjective score was 83.38+/-9.4 in Group 1 and 79.92+/-11.01 in Group 2 (P>.05). The side to side laxity as measured with the Rolimeter arthrometer was 1.5 mm+/-1 (range 0-3) for Group 1, and 2 mm+/-1 (range 0-3) for Group 2 (P>.05). Femoral Biotransfix fixation and Bio-interference Screws fixation provide comparable mechanical stability and clinical outcome at 13 months follow up. BiotransFix fixation is an effective alternative to other devices. Our preliminary study shows that there is no evidence to prefer femoral transfixation to the more traditional, technically less demanding, and more economical interference screw fixation. A full study requires 368 participants.