Reconstruction of the anterior cruciate ligament in females: A comparison of hamstring versus patellar tendon autograft

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Strategies to promote tendon-bone healing after anterior cruciate ligament reconstruction: Present and future

At present, anterior cruciate ligament (ACL) reconstruction still has a high failure rate. Tendon graft and bone tunnel surface angiogenesis and bony ingrowth are the main physiological processes of tendon-bone healing, and also the main reasons for the postoperative efficacy of ACL reconstruction. Poor tendon-bone healing has been also identified as one of the main causes of unsatisfactory treatment outcomes. The physiological process of tendon-bone healing is complicated because the tendon-bone junction requires the organic fusion of the tendon graft with the bone tissue. The failure of the operation is often caused by tendon dislocation or scar healing. Therefore, it is important to study the possible risk factors for tendon-bone healing and strategies to promote it. This review comprehensively analyzed the risk factors contributing to tendon-bone healing failure after ACL reconstruction. Additionally, we discuss the current strategies used to promote tendon-bone healing following ACL reconstruction.

Re-rupture rate and the post-surgical meniscal injury after anterior cruciate ligament reconstruction with the Press-Fit-Hybrid®-technique in comparison to the interference screw technique: a retrospective analysis of 200 patients with at least 3 years follow-up

BACKGROUND

There is currently no consensus regarding the preferred surgical procedure for the reconstruction of anterior cruciate ligament (ACL). The interference screw technique is widely used, but has been associated with a risk of graft damage. The Press-Fit-Hybrid®-technique is one of the alternatives for biological ACL-reconstruction with minimal implant requirements. The hypothesis of this retrospective analysis is, that the Press-Fit-Hybrid®-technique leads to better results with respect to re-rupture rate and secondary meniscal lesion than the interference-screw-technique.

METHODS

To compare the re-rupture rate of the interference-screw-technique (IF) used until 2015 with the currently used Press-Fit-Hybrid®-technique (PFH), the last 100 patients of the IF-group and the first 100 patients of the PFH-group were retrospectively analyzed. Primary outcomes were re-rupture rate, complications and secondary meniscal injury. Additionally, laxity, Lachman and Pivot-shift and range of motion were evaluated.

RESULTS

A mean follow-up of 4.2 and 5.3 years revealed 4% and 9% re-rupture rates and 1% and 2% complication rates in the PFH- and IF-group, respectively. In the PFH-group there were no re-ruptures in patients older than 23 years. Secondary meniscal injury post-surgery was 6% and 9% for the PFH and IF-group, respectively. Knee stability was similar in both groups. Range of motion was significantly better in the PFH-group, with 136° of flexion, 6 months after surgery.

CONCLUSION

For ACL-reconstruction the Press-Fit-Hybrid®-technique is an alternative new method. Low level of secondary meniscal lesions after surgery and high stability, is known to prevent later arthrosis of the knee. The encouraging observed trend of the reduction of the re-rupture rate in revision surgery and in young patients using the Press-Fit-Hybrid®-technique in comparison to the interference-screw-technique must be confirmed with further studies.

LEVEL OF EVIDENCE

Therapeutic Level III, retrospective cohort study.

Hamstring autograft utilization in reconstructing anterior cruciate ligament: Review of harvesting techniques, graft preparation, and different fixation methods

Rupture of the anterior cruciate ligament (ACL) is a common orthopedic injury. Various graft options are available for the reconstruction of ruptured ACL. Using the hamstring muscle as an autograft was first described in 1934, and it remains a commonly harvested graft for ACL reconstruction. Hamstring autografts can be harvested using the traditional anteromedial approach or the newer posteromedial technique. An isolated semitendinosus tendon can be used or combined with the gracilis tendon. There are numerous methods for graft fixation, such as intra-tunnel or extra-tunnel fixation. This comprehensive review discusses the different hamstring muscle harvesting techniques and graft preparation options and fixation methods. It provides a comprehensive overview for choosing the optimal surgical technique when treating patients.

Graft Choice for Anterior Cruciate Ligament Reconstruction in Women Aged 25 Years and Younger: A Systematic Review

CONTEXT

Although anterior cruciate ligament (ACL) tears are relatively common in athletic populations, few studies have systematically reviewed graft choice in young women.

OBJECTIVE

To quantitatively and qualitatively examine reported outcomes for graft choice in women aged 25 years and younger undergoing primary ACL reconstruction.

DATA SOURCE

A systematic review was performed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. An electronic search in the PubMed (includes MEDLINE) and EMBASE databases was completed using a combination of key terms.

STUDY SELECTION

Studies were included if they reported graft choice outcomes in women aged 25 years and younger.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

The following information was extracted: title, author, year of publication, number of female patients and age, graft type, follow-up, and patient-reported outcome measures. The following outcome scores were identified as being reported or not reported by each study: graft failure, contralateral ACL (CACL) rupture, IKDC (International Knee Documentation Committee), graft survival (Kaplan-Meier), Lysholm, Tegner, KT-1000, kneeling pain, return to sport, and Lachman.

RESULTS

Of 1170 identified articles, 16 met inclusion criteria, reporting on 1385 female patients aged 25 years and younger. Comparison of 655 bone-patellar tendon-bone (BPTB) versus 525 hamstring tendon (HT) autografts showed significant differences in mean failure rate between BPTB autografts (6.13% ± 2.58%) and HT autografts (17.35% ± 8.19%), P = 0.001. No statistically significant differences in CACL failure rates were found between BPTB autografts and HT autografts (P = 0.25). Pooled results for IKDC were possible in 3 of the HT autograft studies, showing a mean score of 88.31 (95% CI 83.53-93.08). Pooled Lysholm score results were possible in 2 of the HT autograft studies, showing a mean score of 93.46 (95% CI 91.90-95.01).

CONCLUSION

In female patients aged 25 years and younger, BPTB autografts showed significantly less graft failure compared with HT autografts. However, BPTB autografts had comparable patient-reported outcomes compared with HT autografts with the available data. The overall state of evidence for graft choice in female patients aged 25 years and younger is low. Future studies should report statistics by age and sex to allow for further analysis of graft choice for this specific population that is known to be more vulnerable to ACL injury.

Journey around the Notch: A Systematic Review on the History of ACL Reconstruction in the United States

The evolution of anterior cruciate ligament (ACL) surgery, seemingly circular at times, informs and provides context for past and current controversies in ACL management. The purpose of this systematic review is to objectively summarize the historical course of ACL reconstruction and repair in the United States over the last 40 years. Femoral tunnel drilling and graft selection have evolved dramatically over the last few decades. An initial focus on restoring ACL anatomy was for a period sacrificed for decreased operative morbidity. However, recent developments in operative techniques aim to restore ACL anatomy while also achieving minimal operative morbidity. Despite this historically iterative process, there remains no perfect choice for the treatment of ACL tears. Continued research on ACL repair, anatomic graft placement, graft choice, and augmentation will help our patients over the next generation.

Clinical Outcomes of Anterior Cruciate Ligament Reconstruction Using Quadriceps Tendon Autograft Versus Hamstring Tendons Autograft: A Retrospective Analysis

AIM

 The purpose of this retrospective study was to examine the clinical outcomes of anatomic single-bundle anterior cruciate ligament (ACL) reconstruction using a free quadriceps (QUADRI) tendon or a quadrupled hamstring (HAM) autograft.

MATERIAL AND METHOD

The retrospective analysis (Level III, Therapeutic Study) included consecutive patients who underwent ACL reconstruction between April 2017 and April 2020 using either a free quadriceps tendon autograft or a hamstring tendon autograft. All patients underwent ACL reconstruction to treat isolated ACL injuries. The Tegner-Lysholm knee scoring system and the modified Cincinnati knee score were used for evaluation before surgery, and at six weeks, six months, and one-year follow-up time.

RESULTS

 In the present study, 35 people underwent quadriceps (QUADRI) grafts and 35 underwent hamstring (HAM) grafts. The demographic data for the groups were extremely comparable. The mean follow-up length for the HAM group was 11.96±0.28 months, while the QUADRI group had a mean follow-up period of 11.25±0.43 months. No significant variations in the Cincinnati score were observed between the two groups during any of the treatment's follow-up periods. Similarly, the Tegner Lysholm Score revealed no statistically significant differences between clinical outcomes in the HAM and QUADRI groups at all follow-up visits, except for the sixth week.

CONCLUSION

 Clinical outcomes are comparable in terms of stability and subjective assessments following ACL reconstruction using a free quadriceps or hamstring tendon autograft.

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

BACKGROUND

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

PURPOSE/HYPOTHESIS

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

STUDY DESIGN

Systematic review.

METHODS

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

RESULTS

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

CONCLUSION

Studies examining graft choice for anterior cruciate ligament reconstruction may not be as statistically stable as previously thought. Comparative studies and RCTs are at substantial risk for statistical fragility, with few event reversals required to alter significance. The reversal of <4 outcome events in a treatment group can alter the statistical significance of a given result; this is commonly fewer than the number of patients lost to follow-up. Future comparative study analyses might consider including FI and FQ with P values in their statistical analysis.

Quadriceps tendon autograft is an effective alternative graft for posterior cruciate ligament reconstruction in isolated or multiligament injuries: a systematic review

IMPORTANCE

High-grade posterior cruciate ligament (PCL) tears can be a significant cause of patient morbidity and knee instability. The graft of choice for operative repair remains controversial, although recently there has been increased interest in quadriceps tendon (QT) as an autologous graft option.

OBJECTIVE

The purpose of this study was to perform a systematic review to assess reported clinical outcomes of PCL reconstructions using QT autografts.

EVIDENCE REVIEW

A comprehensive review of clinical studies was performed evaluating PCL reconstruction with QT autograft including a systematic search of PubMed, Scopus, Cochrane and Google Scholar databases, and reference lists of relevant papers. Clinical results, stability results, functional outcomes, range-of-motion outcomes, complications and morbidity, and the conclusions of each study were evaluated.

FINDINGS

Seven studies were included in the review of clinical results, including 145 subjects undergoing PCL reconstructions with QT autograft. All studies evaluated quadriceps tendon bone (QT-B) grafts. Among these seven studies, two included isolated PCL reconstruction while five included multiligamentous knee injury reconstruction. These studies suggest that QT-B autograft offers a viable graft option for primary PCL reconstruction with generally favourable patient-reported outcomes, knee stability and range of motion reported along with relatively low complication rates.

CONCLUSIONS AND RELEVANCE

Use of the QT-B autograft may be a reasonable graft option for PCL reconstruction. However, high-quality prospective studies are required to evaluate the long-term safety, efficacy and functional outcomes.

LEVEL OF EVIDENCE

Level IV (Systematic review of Level IV studies).

Patellar Bone-Tendon-Bone Autografts versus Quadriceps Tendon Allograft with Synthetic Augmentation in a Canine Model

Patellar bone-tendon-bone (pBTB) autografts are often considered the "gold standard" for complete anterior cruciate ligament (ACL) reconstruction and are also associated with significant complications and early-onset knee osteoarthritis (OA). A novel quadriceps tendon allograft with synthetic augmentation, or "internal brace" (QTIB), has been reported to have potential advantages for ACL reconstruction based on animal model data. In this preclinical canine comparison study, we hypothesized that QTIB allograft compared with pBTB autograft would provide superior durability for knee stability, function, and prevention of OA. Under approval from our Institutional Animal Care and Use Committee, adult purpose-bred research hounds (n = 10) underwent arthroscopic complete transection of the ACL followed by either an arthroscopic-assisted all-inside ACL reconstruction using the QTIB allograft (n = 5) or pBTB autograft (n = 5). Contralateral knees were used as nonoperated controls (n = 10). Radiographic and arthroscopic assessments were performed at 2 and 6 months, respectively, after surgery. Anterior drawer, internal rotation, lameness, kinetics, pain, effusion, and comfortable range of knee motion were measured at 2, 3, and 6 months. Biomechanical and histologic assessments were performed at 6 months. All reconstructed knees were stable and had intact ACL grafts 6 months after surgery. At 6 months, QTIB reconstructed knees had significantly less lameness, lower pain, less effusion, and increased range of motion when compared with BTB knees (p < 0.05). BTB knees had significantly higher radiographic OA scores than QTIB knees at 6 months (p < 0.05). Superior outcomes associated with QTIB allograft may be due to the lack of donor site morbidity, the use of a robust tendon graft, and/or protection of the graft from the synthetic augmentation. Robust tendon grafts combined with a synthetic internal brace and platelet-rich plasma (PRP) may allow for more rapid and robust tendon-bone healing and graft "ligamentization," which protects the graft from early failure and rapid OA development that can plague commonly-used allografts.

Biomechanical Properties of Small-Size Hamstring Autografts

Purpose

To evaluate small-size hamstring (HS) autografts for biomechanical properties and determine a threshold diameter necessary for appropriate reconstruction.

Methods

In a controlled laboratory setting, biomechanical testing was performed upon 15 hamstring autografts. The grafts were divided into three groups by diameter, with five grafts each at diameter sizes of 6, 7, and 8 mm. Testing of the specimens was performed using an MTS 858 (Materials Testing System, Eden Prairie, MN). We determined load to failure by looking at the maximum load as well as the stiffness of the graft. Statistical analysis was performed via analysis of variance (ANOVA) testing with Tukey's post-hoc test and P-values set at 0.05.

Results

There was a significant difference in ultimate tensile strength for the different size grafts: 1990 +/- 302.42 N for 6 mm grafts (n=5), 2179 +/- 685.36 N for the 7 mm grafts (n=5), and 3074 +/- 781 N for 8 mm grafts (n=5). This was statistically significant for the group overall (p=0.039), as well as between the 6 mm and 8 mm grafts (p=0.044). Graft stiffness for the 6 mm grafts was 317 +/- 85 N (n=5), 288.6 +/- 66 for 7 mm grafts (n=5), and 428.053 +/- 83 for 8 mm grafts (n=5). This achieved statistical significance for the group overall (p =0.037) as well as between the 8 mm and 7 mm grafts.

Conclusions

The biomechanical data presented here demonstrate that graft diameter is highly correlated with ultimate tensile strength and stiffness.

Clinical relevance

When viewing this biomechanical data in conjunction with prior clinical data, consideration should be given for the supplementation of an HS autograft as the size decreases below 8 mm.

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.

Comparison of Short-term Biodex Results After Anatomic Anterior Cruciate Ligament Reconstruction Among 3 Autografts

Background:

An individualized approach to anterior cruciate ligament reconstruction (ACLR) typically includes criteria-based postoperative rehabilitation. However, recent literature has suggested residual quadriceps weakness up to 12 months after ACLR, especially with a quadriceps tendon (QT) autograft.

Hypothesis:

The QT would have poorer quadriceps strength symmetry at 5 to 8 months compared with the hamstring tendon (HS) and patellar tendon (BPTB), but there would be no significant difference at 9 to 15 months among all 3 groups.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients who underwent anatomic primary ACLR with an autograft were reviewed retrospectively. Isometric quadriceps and hamstring strength measurements were obtained clinically at 5 to 8 months and 9 to 15 months postoperatively. Return-to-running and return-to-play criteria included greater than 80% and 90% quadriceps strength symmetry, respectively.

Results:

A total of 73 patients with 5- to 8-month follow-up were identified, and 52 patients had 9- to 15-month data. The QT group had a significantly lower quadriceps index at 5 to 8 months (69.5 ± 17.4) compared with the BPTB (82.8 ± 14.6; P = .014) and the HS (86.0 ± 18.6; P = .001) groups. More patients with an BPTB autograft met criteria for return to running and return to play (60% and 47%, respectively) compared with the QT group (26% and 13%, respectively) at 5 to 8 months. Given the sample sizes available, we observed no significant difference in the quadriceps index and return-to-play and return-to-running criteria at 9 to 15 months among those undergoing ACLR with a QT, BPTB, or HS graft.

Conclusion:

Patients undergoing ACLR with a QT graft demonstrated clinically meaningful quadriceps asymmetry at 5 to 8 months and 9 to 15 months postoperatively. Additionally, fewer patients in the QT group met criteria for return to play and running at 5 to 8 months than the BPTB and HS groups. These data suggest that a longer time to return to play and specific rehabilitation protocols that emphasize quadriceps strengthening may be necessary because of residual quadriceps weakness after ACLR with a QT graft.

Clinical outcomes after ACL reconstruction with free quadriceps tendon autograft versus hamstring tendons autograft. A retrospective study with a minimal follow-up two years

OBJECTIVE

The aim of this retrospective study was to compare the clinical outcomes of anatomic single bundle ACL reconstruction using either a free quadriceps tendon autograft or a quadrupled hamstring autograft with a minimum follow-up of 24 months.

METHODS

Consecutive patients undergoing ACL reconstruction using either a free quadriceps tendon autograft or hamstring tendon autograft from January 2013 to December 2014 were included. ACL reconstruction was done in all patients due to isolated ACL tears. Patients with associated cartilage lesions > Outerbridge III, meniscal lesions in need of meniscectomy or repair as well as patients with prior knee surgery on the affected or contralateral knee were excluded. The primary outcome evaluation was the side-to-side difference in instrumented Lachman testing. Secondary outcome evaluation consisted in the Lysholm, modified Cincinnati and SF-36 scores. Side-to-side difference in range of motion and thigh diameter was also documented.

RESULTS

After applying the inclusion/exclusion criteria, a total of 82 patients were identified and 72 (87.8%) presented to the hospital for follow-up. There were 39 patients with quadriceps graft (30.64 ± 8.71, range: 18-53 years) and 33 patients with hamstrings (28.60 ± 6.74, range: 18-46 years). No statistically significant difference between groups was detected with regard to KT-1000 measurements (p = 0.326). No significant difference was found between the mean postoperative Lysholm (p = 0.299), the modified Cincinnati (p = 0.665) and the general SF-36 scores between groups (p = 0.588). Less side-to-side thigh diameter difference was noted in the quadriceps graft group (p = 0.026).

CONCLUSION

In conclusion, similar clinical results, in terms of stability and subjective measures, can be obtained after ACL reconstruction both with a free quadriceps and a 4-strand hamstring tendons autograft.

LEVEL OF EVIDENCE

Level III, Therapeutic Study.

Anterior Cruciate Ligament Reconstruction in Young Females: A Systematic Review of Patellar Tendon Versus Hamstring Tendon Autografts

A systematic review was performed to compare patellar tendon-bone (BTB) and hamstring tendon (HS) autografts following anterior cruciate ligament reconstruction in young females, young patients, or females. One study compared BTB and HS in young females and found a lower rate of graft failure with BTB (P<.02). Of the 11 studies that made this comparison in females, 1 reported decreased laxity in females with BTB (P=.035). Of 4 studies comparing autografts in young patients, 1 reported a decreased rate of graft failure with BTB (P=.036). Further studies making this comparison specifically in young females are warranted. [Orthopedics. 2019; 42(3):e295-e304.].

Increased knee laxity with hamstring tendon autograft compared to patellar tendon autograft: a cohort study of 5462 patients with primary anterior cruciate ligament reconstruction

PURPOSE

To compare anterior knee laxity and patient-reported outcome measures (PROMs) between anterior cruciate ligament reconstruction (ACLR) performed with bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) autografts and, moreover, to study any correlation between postoperative anterior knee laxity and PROMs.

METHODS

Patients who underwent primary ACLR at Capio Artro Clinic, Stockholm, Sweden, from January 2000 to October 2015, were identified in our local database. Instrumented laxity measurements and PROMs were reviewed. The KT-1000 arthrometer, with an anterior tibial load of 134-N, was used to evaluate knee laxity preoperatively and at the 6-month follow-up. The Lysholm score was collected preoperatively and at 6 months postoperatively. The Knee injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and at the 1-year follow-up.

RESULTS

A total of 5462 primary ACLRs, 692 BPTBs and 4770 HT autografts were included in the study. All the patients showed a significant reduction in knee laxity from preoperatively to postoperatively (BPTB group: from 3.8 ± 2.6 to 1.2 ± 2.1 mm; HT group: from 3.6 ± 3.1 to 1.8 ± 2.2 mm; P < 0.001 for both). The HT group showed a significantly increased postoperative knee laxity compared with the BPTB group (1.8 ± 2.2 vs 1.2 ± 2.1 mm; P < 0.001). The mean anterior tibial translation (ATT) reduction from preoperative to postoperative was significantly larger for the BPTB graft compared with the HT graft (2.7 ± 2.2 vs 1.7 ± 2.6 mm; P < 0.001). A significantly higher rate of "surgical failures", defined as a postoperative side-to-side (STS) difference > 5 mm, was found in the HT group compared with the BPTB group at follow-up (4.3 vs 2.4%; P < 0.001). A significantly larger improvement was found in the HT group compared with the BPTB group for the KOOS Pain (9.5 vs 8.0; P = 0.02), Activities of Daily Living (7.2 vs 5.7; P = 0.006), Sports (24.2 vs 15.3; P < 0.001) and Quality of Life (25.8 vs 22.1; P = 0.001) subscales. No significant difference regarding the mean improvement in the Lysholm knee score was found between the two grafts (BPTB group: 14.5, HT group: 14.0; n.s.). No correlation between postoperative anterior knee laxity and PROMs was found in either graft group.

CONCLUSION

Primary ACLR performed with HT autograft resulted in greater postoperative anterior knee laxity and significantly more surgical failures (STS > 5 mm) compared with BPTB autograft. The BPTB autograft showed a larger anterior knee laxity reduction (ATT reduction) in conjunction with primary ACLR. The HT autograft led to a significantly larger improvement in four of five KOOS subscales from preoperatively to the 1-year follow-up, compared with BPTB autograft. There was no association between postoperative anterior knee laxity and PROMs for either graft. The findings of the present study provide clinicians with valuable information regarding differences in knee laxity and subjective knee function between BPTB and HT autograft after primary ACLR. The use of BPTB autograft should be considered for patients with high knee stability demands.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

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.

A tourniquet-less technique using saline epinephrine irrigation system in an arthroscopic ACL reconstruction in patient with history of popliteal artery ligation

INTRODUCTION

Pneumatic tourniquets use in surgery to create a bloodless surgical field. The majority of orthopaedic surgeon use a tourniquet inflated above systemic blood pressure during arthroscopic anterior cruciate ligament (ACL) reconstruction. A tourniquet use is not free of complications. The disadvantage of tourniquet application include an increased risk of vascular injuries. An arthroscopic ACL reconstruction in patient with history of popliteal artery ligation is challenging. The popliteal artery is the major contributor to the blood supply of the knee joint. This arthroscopic ACL reconstruction does not use tourniquets to preserve the collateral circulation that provides blood supply to the leg and prevent the vascular injuries in patient with history of popliteal artery ligation.

PRESENTATION OF CASE

A-23-year-old female brought to the General Hospital with ACL rupture caused by car accident. The patient had a history of knee dislocation with an open wound and rupture of popliteal artery. The patient underwent open reduction surgery of her right knee joint by orthopaedic surgeon and popliteal artery repair by vascular surgeon. The reduction of the knee joint went good, but the popliteal artery repair was failed and the patient underwent popliteal artery ligation 1 week later. The patient received non-operative treatment for her ACL rupture. After 2 years, she did not get a good improvement to her knee and the patient still felt a giving way sensation and unstability of her knee. Then the patient transferred to the General Hospital for ACL reconstruction, but the surgery required a special consideration in the technique of ACL reconstruction because of the history of popliteal artery ligation.

DISCUSSION

Positioning of the patient for ACL reconstruction The patient supine on an operating table. The leg to undergo surgery has no tourniquet placed because the patient had no popliteal artery and this operation needs to preserve and prevent the vascular ischemia of the collateral artery. Operating room set up with the patient prepped and draped for the diagnostic arthroscopy. It shows a normal cartilage, rupture of the ACL and PCL, rupture of body of the lateral meniscus in the white zone and rupture of body of the medial meniscus in the white zone. To make the bloodless arthroscopic field, cold saline and epinephrine pumped into the knee. Partial meniscectomy of the lateral and medial meniscus was performed. Single bundled ACL reconstruction was performed using hamstring autograft of the contralatelal site with the diameter was 8 mm and fixated by XO button and bioscrew (ConMed). After six months follow up, the patient did not feel giving way, catched, or locking. The patient had a good vascularity of the right lower extremity. There is improvement in Modified Cincinnati Rating System. The pre operative score was 49. The post operative score was 90. Tegner Lysholm Knee Scoring system before surgery was 35 and post operative score was 91. IKDC Scoring before surgery was 21,8 and the score had a good improvement. The IKDC Scoring after surgery was 73,6.

CONCLUSION

ACL reconstruction in patient with popliteal artery ligation is challenging. A tourniquet-less technique using a cold saline and epinephrine solution can be successfully done for pressure controlled into the knee to preserve the collateral arteries flow to the distal limb while still permitting acceptable visual in operative field with good outcome after the surgery.

Influence of Graft Diameter on Functional Outcomes After Anterior Cruciate Ligament Reconstruction: A Prospective Study with a 1-Year Follow-Up

Background

The aim of this study was to determine whether graft size is associated with recurrent instability and insufficient functional outcomes after ACL reconstruction.

Material/Methods

We analyzed 214 consecutive patients with a completed follow-up of 12 months: 55 (25.7%) women and 159 (74.3%) men. Patients were divided into 3 groups according to the diameter of the middle of the hamstring graft. Follow-up examinations were performed pre-surgery and 3, 6, and 12-months postoperatively, and laxity assessments were performed using GNRB^®. Differential laxity measured at 134N (Δ134=heathy vs. operated side). A “residual laxity” of the ACLR was defined as Δ134N>3 mm.

Results

The results of the General Linear Model (Repeated Measures) showed that there was a significant main effect of time factor (F=379.759, p<0.001, η²_p=0.681) on differential laxity. We found statistically significant differences (p<0.001) in assessments of differential laxity pre-surgery and at 3, 6, and 12 months postoperatively (time factor). Tegner activity score at 12 months after reconstruction significantly differed when comparing patients with “residual laxity” (4.23±0.83) and others (4.85±1.17) (p=0.038). The study revealed a positive correlation between Tegner activity score at 12 months after surgery and pre-injury Tegner activity score (r=0.728, p<0.001) and negative correlation between age (r=−0.43, p<0.001) or BMI (r=−0.33, p<0.001).

Conclusions

Our study revealed that graft diameter is not associated with recurrent instability and does not affect laximetry results. The multiple regression model we developed made it possible to predict the Tegner activity score at 12 months after reconstruction based on pre-injury Tegner activity score, age (years), and BMI (kg/m²) of the patient.

Comparison of Return to Pre-Injury Sport After 10 mm Size Bone-Patellar Tendon-Bone (BPTB) versus 8 mm Hamstring Anterior Cruciate Ligament Reconstruction: A Retrospective Study with a Two-Year Follow-Up

Background

The aim of this study was to evaluate the reconstruction of a torn anterior cruciate ligament (ACL) with 10 mm diameter BPTB (bone-patellar tendon-bone) autograft versus 8 mm HT (hamstring tendon) autografts, to compare the ability to restore pre-injury sports activities and reduce revision risk after these procedures.

Material/Methods

A prospective clinical review was performed to compare results of patients who underwent primary anatomical ACLR with 10 mm BPTB autografts with patients who underwent 8 mm diameter HT autografts, between January 2011 and January 2014.

Results

There were 183 patients evaluated: the 8 mm HT group showed statistically significant higher knee laxity values compared to the 10 mm BPTB group (p=0.042), and significant difference were detected in subjective International Knee Documentation Committee (IKDC) evaluation scores; the average subjective IKDC evaluations after two-year follow-up in the HT group was 88.45±2.8 versus 89.24±2.5 in BPTB group (p=0.047). In the evaluation of the IKDC objective protocol, results were excellent and good in 83 patients (94.3%) after BPTB and in 78 patients (82%) after HT ACLR (p<0.05). The average score on the Tegner activity scale in the HT group decreased from 6.5 at pre-injury to 5.8 at two-year follow-up (p<0.001) and from 6.7 at pre-injury to 6.5 at two-year follow-up in the BPTB group (p=0.4). The ability to restore pre-injury sports activities was higher in the BPTB group (6.5) versus the HT group (5.8) (p<0.001). Revision was required for two patients (2.2%) in the BPTB group compared with 14 patients (14.7%) in the HT group (p<0.05).

Conclusions

Smaller HT graft size was a predictor of higher knee laxity and greater revision risk at two-year post primary ACL reconstruction. Larger diameter BPTB ACL grafts had a better ability to restore knee stability and greater ability to restore pre-injury sports activities.

Hamstring Graft Preparation Techniques for Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament reconstruction is one of the most commonly performed procedures in orthopaedics, with more than 125,000 performed in the United States per year. There are several reconstruction graft choices that can be used to reconstruct the native anterior cruciate ligament, with autograft hamstring tendons being one of the most commonly used. Preparation of a hamstring autograft varies depending on patient characteristics and physician preference. The purpose of this Technical Note is to describe in detail different variants of hamstring graft preparation techniques that are commonly used in practice.

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.

Anatomic Anterior Cruciate Ligament Reconstruction via Independent Tunnel Drilling: A Systematic Review of Randomized Controlled Trials Comparing Patellar Tendon and Hamstring Autografts

PURPOSE

To collect the highest level of evidence comparing anatomic anterior cruciate ligament (ACL) reconstruction via independent tunnel drilling using bone-patellar tendon-bone (BTB) and hamstring tendon (HT) autografts in terms of clinical outcome and failure rate.

METHODS

We performed a systematic review of clinical trials that randomized patients to ACL reconstruction with either BTB or HT autografts with a minimum 2-year follow-up. Only trials using independent tunnel drilling, including outside-in and anteromedial portal techniques, for both autografts were eligible for inclusion, whereas all transtibial studies were excluded. Study design, demographics, surgical technique, rehabilitation protocol, and clinical outcomes were compiled. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Quality assessment was performed using the Coleman Methodological Scale (CMS).

RESULTS

Six published studies reporting on 5 randomized controlled trials (RCTs) met the inclusion criteria. No study reported a difference in rerupture rate between BTB and HT. BTB-reconstructed knees experienced a greater incidence of anterior knee pain or crepitus in 2/7 trials and radiographic evidence of degenerative change in 3/7 trials. HT-reconstructed knees had increased instrumented laxity in 2/7 trials and less knee flexion strength postoperatively.

CONCLUSIONS

This study collects all available Level I and II evidence for anatomic ACL reconstruction using BTB and HT grafts. According to the data presented in these studies, clinical outcome scores and failure rates showed no differences for anatomic reconstruction using either autograft. However, in some studies, BTB-reconstructed knees experienced a greater incidence of anterior knee pain and radiographic evidence of degenerative change, and in others, HT-reconstructed knees had increased laxity and less knee flexion strength. In our opinion, both BTB and HT autografts remain valid options for ACL reconstruction when using anatomic drilling techniques, providing a stable knee with reliable return to activity.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

Causes of Failure of Anterior Cruciate Ligament Reconstruction and Revision Surgical Strategies

Purpose

Long-term outcomes of anterior cruciate ligament (ACL) reconstruction are good or excellent; however, 0.7%–20% of patients suffer from recurrent instability due to graft failure. The purpose of this paper was to analyse failure aetiology and the possibilities of revision surgical strategies, with a description of our experience. We obtained optimal and good results in most of our patients.

Materials and Methods

We retrospectively reviewed 42 patients who underwent revision surgery (43 revisions) due to relapsing instability after ACL reconstruction between 2006 and 2015. We used allografts in 39 cases and autografts in 4 cases.

Results

The 85.7% of the patients obtained optimal results (normal knee; group A) and the 7.2% obtained good results (nearly normal knee; group B) according to the International Knee Documentation Committee score. The most frequent failure causes were traumatic events, non-anatomic tunnel placement, and lack of graft incorporation.

Conclusions

A correct revision surgery requires accurate patient evaluation and knee imaging. Preoperative planning starts with the identification of the cause of failure of the primary reconstruction. Then, the most suitable procedure should be determined for each case. It is also important to accurately inform the patient of all the complexity of an ACL revision surgery even if it is a procedure with high rates of excellent and good outcomes.

Modified Broström Procedure for Chronic Lateral Ankle Instability in Patients With Generalized Joint Laxity

BACKGROUND

Generalized joint laxity (GJL) has been considered a risk factor for late failure of ligament reconstruction in the knee; however, it is not known whether GJL is the cause of recurrent instability after the modified Broström procedure for chronic lateral ankle instability.

PURPOSE

To compare the clinical results of the modified Broström procedure for chronic lateral ankle instability in patients with or without GJL.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 100 patients (100 ankles) who underwent the modified Broström procedure were divided into 2 groups, with or without GJL, according to the Beighton criteria. Age and body mass index were matched between the 2 groups. The mean follow-up duration was 43.3 months in the laxity group (44 ankles; Beighton score ≥5) and 42.9 months in the nonlaxity group (56 ankles).

RESULTS

The mean preoperative Karlsson and American Orthopaedic Foot and Ankle Society (AOFAS) scores were a respective 53.2 and 60.9 in the laxity group and 53.9 and 62.6 in the nonlaxity group, and these scores improved to 87.4 and 89.5, respectively, in the laxity group and to 94.1 and 94.8, respectively, in the nonlaxity group at final follow-up. The mean preoperative talar tilt angle and anterior talar translation were a respective 12.5° and 8.8 mm in the laxity group and 10.8° and 8.5 mm in the nonlaxity group, and these values improved to 7.3° and 6.0 mm, respectively, in the laxity group and to 5.2° and 5.0 mm, respectively, in the nonlaxity group at final follow-up. Failure rates were 11.4% (5 patients) in the laxity group and 1.8% (1 patient) in the nonlaxity group. Significant differences were found between the 2 groups in terms of the Karlsson score, AOFAS score, talar tilt angle, anterior talar translation, and failure rate at final follow-up (P < .05).

CONCLUSION

Patients with GJL showed inferior outcomes and a higher failure rate compared with patients without GJL. Therefore, GJL appears to be a risk factor associated with recurrent instability after the modified Broström procedure.

Is There a Difference in Graft Motion for Bone-Tendon-Bone and Hamstring Autograft ACL Reconstruction at 6 Weeks and 1 Year?

BACKGROUND

Bone-patellar tendon-bone (BTB) grafts are generally believed to heal more quickly than soft tissue grafts after anterior cruciate ligament (ACL) reconstruction, but little is known about the time course of healing or motion of the grafts within the bone tunnels.

HYPOTHESIS

Graft-tunnel motion will be greater in hamstring (HS) grafts compared with BTB grafts and will be less at 1 year than at 6 weeks.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve patients underwent anatomic single-bundle ACL reconstruction using HS or BTB autografts (6 per group) with six 0.8-mm tantalum beads embedded in each graft. Dynamic stereo x-ray images were collected at 6 weeks and 1 year during treadmill walking and stair descent and at 1 year during treadmill running. Tibiofemoral kinematics and bead positions were evaluated. Graft-tunnel motion was based on bead range of motion during the loading response phase (first 10%) of the gait cycle.

RESULTS

During treadmill walking, there was no difference in femoral tunnel or tibial tunnel motion between BTB or HS grafts at 6 weeks (BTB vs HS: 2.00 ± 1.05 vs 1.25 ± 0.67 mm [femoral tunnel]; 1.20 ± 0.63 vs 1.27 ± 0.71 mm [tibial tunnel]), or 1 year (BTB vs HS: 1.62 ± 0.76 vs 1.08 ± 0.26 mm [femoral tunnel]; 1.58 ± 0.75 vs 1.68 ± 0.53 mm [tibial tunnel]). During stair descent, there was no difference in femoral or tibial tunnel motion between BTB and HS grafts at 6 weeks or 1 year. With running, there was no difference between graft types at 1 year. For all results, P values were > .05. Knee kinematics were consistent with the literature.

CONCLUSION

During walking and stair descent, ACL reconstruction using suspensory fixation yielded no difference between graft types in femoral or tibial tunnel motion at 6 weeks or 1 year. All subjects were asymptomatic with knee kinematics similar to that of the literature. The significance of persistent, small (1 to 3 mm) movements at 1 year for healing or graft performance is unknown.

CLINICAL RELEVANCE

These study results may have significant implications for graft choice, rehabilitation strategies, and timing for return to sports.

Do graft diameter or patient age influence the results of ACL reconstruction?

PURPOSE

Hamstring tendons are commonly used as a graft source for ACL reconstruction. This study seeks to determine whether either the diameter of the tendon graft or the age of the patient influences the outcome of the ACL reconstruction when measured using a standard, previously validated laxity measurement device.

METHODS

This is a retrospective study of 88 patients who underwent ACL reconstruction with a short, quadrupled tendon technique, using the semitendinosus ± gracilis tendons. Patients included in this study were sequential, unilateral, complete ACL ruptures. The patients were followed for a minimum of 1 year postoperatively, with a mean follow-up of 26 months. Patients were divided into three groups according to the diameter (Ø) of the graft: group 1 (32 patients): 8 mm ≤ Ø ≤ 9 mm; group 2 (28 patients): 9 mm < Ø ≤ 10 mm; and group 3 (28 patients): Ø > 10 mm. Three groups with differential laxity at 134 N (Δ134 = healthy side vs. operated side) measured with the laximeter GNRB(®) were compared. The risk of residual laxity (OR) between the three groups taking age, gender, BMI and meniscus status into account was calculated. A side-to-side laxity >3 mm was considered as a residual laxity.

RESULTS

The mean patient age at the time of reconstruction was 29.4 years. The three groups were comparable. Postoperative Δ134 was 1.50 ± 1.3, 1.59 ± 1.5 and 2 ± 1.7 mm for groups 1 through 3, respectively. Δ134 > 3 mm was observed in three patients in group 1, four patients in group 2 and nine patients in group 3. As compared to group 1, OR was 1.46 (95 % CI 0.35-6.05) and 3.31 (95 % CI 0.89-12.34) in groups 2 and 3, respectively. Adjustment for age, gender, BMI and meniscus did not change the estimates [OR 1.44 (95 % CI 0.34-6.16) and 3.92 (95 % CI 1-15.37)] in groups 2 and 3, respectively. Patients younger than 20 had a significantly higher average postoperative laximetry (2.4 ± 1.5 mm) compared to those aged 20 years and over (1.5 ± 1.5 mm) (p = 0.03), regardless of the diameter of the graft.

CONCLUSION

The diameter of the graft between 8 and 10 mm does not affect the laximetric results of an ACL reconstruction. Therefore, there does not appear to be a benefit to harvesting and adding further tissue to increase the diameter of the graft above 10 mm. Patients younger than 20 represent a population at risk of graft elongation. In these patients at risk, postoperative management needs to be modified (delayed weight bearing, articulated splinting, slower rehabilitation) in the first months.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Reruptures, Reinjuries, and Revisions at a Minimum 2-Year Follow-up: A Randomized Clinical Trial Comparing 3 Graft Types for ACL Reconstruction

OBJECTIVE

To evaluate the predictive factors for traumatic rerupture, reinjury, and atraumatic graft failure of anterior cruciate ligament (ACL) reconstruction at a minimum 2-year follow-up.

DESIGN

Double-blind randomized clinical trial (RCT) with intraoperative computer-generated allocation.

SETTING

University-based orthopedic referral practice.

PATIENTS

Three hundred thirty patients with isolated ACL deficiency were equally randomized to (1) patellar tendon (PT; mean, 29.2 years), (2) quadruple-stranded hamstring tendon (HT; mean, 29.0 years), and (3) double bundle using HT (DB; mean, 28.8 years). Three hundred twenty-two patients completed 2-year follow-up.

INTERVENTIONS

Anatomically positioned primary ACL reconstruction with PT, HT, and DB autografts.

MAIN OUTCOME MEASURES

Proportions of complete traumatic reruptures, traumatic reinjuries (complete reruptures and partial tears), atraumatic graft failures, and contralateral ACL tears. Logistic regression assessed 5 a priori determined independent predictors: chronicity, graft type, age, sex, and Tegner level.

RESULTS

More complete traumatic reruptures occurred in the HT and DB groups: PT = 3; HT = 7; DB = 7 (P = 0.37). Traumatic reinjuries statistically favored PT reconstructions: (PT = 3; HT = 12; DB = 11; P = 0.05). Atraumatic graft failures were not different: PT = 16; HT = 17; DB = 20 (P = 0.75). Younger age was a significant predictor of complete traumatic reruptures and traumatic reinjuries (P < 0.01). Higher activity level, males, and patients with HT, DB, and acute reconstructions had greater odds of reinjury. None of these factors reached statistical significance. Contralateral ACL tears were not different between groups, but trends suggested that younger females were more likely to have a contralateral ACL tear.

CONCLUSIONS

More traumatic reinjuries occurred with HT and DB grafts. Younger age was a predictor of complete traumatic rerupture and traumatic reinjury, irrespective of graft type.

LEVEL OF EVIDENCE

Level 1 (Therapeutic Studies).

CLINICAL RELEVANCE

This article describes the complete traumatic graft rerupture, partial traumatic ACL tear, atraumatic graft failure, and contralateral ACL tear rates observed at 2 years postoperatively in a large double-blind RCT comparing PT, single-bundle hamstring, and double-bundle hamstring ACL reconstructions. The odds and predictive factors of traumatic rerupture and reinjury are also evaluated.

Stem cell therapy: a promising biological strategy for tendon-bone healing after anterior cruciate ligament reconstruction

Tendon-bone healing after anterior cruciate ligament (ACL) reconstruction is a complex process, impacting significantly on patients' prognosis. Natural tendon-bone healing usually results in fibrous scar tissue, which is of inferior quality compared to native attachment. In addition, the early formed fibrous attachment after surgery is often not reliable to support functional rehabilitation, which may lead to graft failure or unsatisfied function of the knee joint. Thus, strategies to promote tendon-bone healing are crucial for prompt and satisfactory functional recovery. Recently, a variety of biological approaches, including active substances, gene transfer, tissue engineering and stem cells, have been proposed and applied to enhance tendon-bone healing. Among these, stem cell therapy has been shown to have promising prospects and draws increasing attention. From commonly investigated bone marrow-derived mesenchymal stem cells (bMSCs) to emerging ACL-derived CD34+ stem cells, multiple stem cell types have been proven to be effective in accelerating tendon-bone healing. This review describes the current understanding of tendon-bone healing and summarizes the current status of related stem cell therapy. Future limitations and perspectives are also discussed.

High-purity magnesium interference screws promote fibrocartilaginous entheses regeneration in the anterior cruciate ligament reconstruction rabbit model via accumulation of BMP-2 and VEGF

Interference screw in the fixation of autologous tendon graft to the bone tunnel is widely accepted for the reconstruction of anterior cruciate ligament (ACL), but the regeneration of fibrocartilaginous entheses could hardly be achieved with the traditional interference screw. In the present work, biodegradable high-purity magnesium (HP Mg) showed good cytocompatibility and promoted the expression of bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF), fibrocartilage markers (Aggrecan, COL2A1 and SOX-9), and glycosaminoglycan (GAG) production in vitro. The HP Mg screw was applied to fix the semitendinosus autograft to the femoral tunnel in a rabbit model of ACL reconstruction with titanium (Ti) screw as the control. The femur-tendon graft-tibia complex was retrieved at 3, 6, 9 and 12 weeks. Gross observation and range of motion (ROM) of the animal model reached normal levels at 12 weeks. No sign of host reaction was found in the X-ray scanning. The HP Mg group was comparable to the Ti group with respect to biomechanical properties of the reconstructed ACL, and the ultimate load to failure and stiffness increased 12 weeks after surgery. In the histological analysis, the HP Mg group formed distinct fibrocartilage transition zones at the tendon-bone interface 12 weeks after surgery, whereas a disorganized fibrocartilage layer was found in the Ti group. In the immunohistochemical analysis, highly positive staining of BMP-2, VEGF and the specific receptor for BMP-2 (BMPR1A) was shown at the tendon-bone interface of the HP Mg group compared with the Ti group. Furthermore, the HP Mg group had significantly higher expression of BMP-2 and VEGF than the Ti group in the early phase of tendon-bone healing, followed by enhanced expression of fibrocartilage markers and GAG production. Therefore we proposed that the stimulation of BMP-2 and VEGF by Mg ions was responsible for the fibrochondrogenesis of Mg materials. HP Mg was promising as a biodegradable interference screw with the potential to promote fibrocartilaginous entheses regeneration in ACL reconstruction.

Quadriceps tendon autograft for anterior cruciate ligament reconstruction: a comprehensive review of current literature and systematic review of clinical results

PURPOSE

The autograft of choice for anterior cruciate ligament (ACL) reconstruction remains controversial. Recently, there has been an increase in interest in the quadriceps tendon as an autologous graft option for ACL reconstruction. The purposes of this study were to provide an in-depth review of quadriceps tendon anatomy, histology, and biomechanics and to synthesize reported clinical outcomes of ACL reconstructions using quadriceps tendon autografts. We hypothesize that (1) published studies on the anatomic, histologic, and biomechanical data regarding the quadriceps tendon support its use as a graft option for ACL reconstruction and (2) clinical outcomes of ACL reconstruction using quadriceps tendon autograft have similar clinical outcomes to bone-patellar tendon-bone autografts with less donor-site morbidity.

METHODS

We performed a comprehensive review of the literature regarding the anatomy, histology, and biomechanical studies of the quadriceps tendon, as well as a systematic review of clinical studies (Level of Evidence I-III) evaluating outcomes after ACL reconstruction using quadriceps tendon autograft. Stability outcomes, functional outcomes, range of motion, patient satisfaction, morbidity, and complications were comprised.

RESULTS

Fourteen studies were included in the review of clinical results, including 1,154 ACL reconstructions with quadriceps tendon autograft. Six studies directly compared quadriceps tendon autografts (n = 383) with bone-patellar tendon-bone autografts (n = 484). Stability outcomes (Lachman, pivot-shift, and instrumented laxity testing), functional outcomes (International Knee Documentation Committee and Lysholm scores), overall patient satisfaction, range of motion, and complications were similar between quadriceps tendon and other graft options. Less donor-site morbidity was seen in patients who underwent quadriceps tendon ACL reconstructions.

CONCLUSIONS

Use of the quadriceps tendon autograft for ACL reconstruction is supported by current orthopaedic literature. It is a safe, reproducible, and versatile graft that should be considered in future studies of ACL reconstruction.

LEVEL OF EVIDENCE

Level III, systematic review of Level I, II, and III studies.

Revision anterior cruciate ligament reconstruction

Context:

Reconstruction of the anterior cruciate ligament (ACL) is one of the most common surgical procedures, with more than 200,000 ACL tears occurring annually. Although primary ACL reconstruction is a successful operation, success rates still range from 75% to 97%. Consequently, several thousand revision ACL reconstructions are performed annually and are unfortunately associated with inferior clinical outcomes when compared with primary reconstructions.

Evidence Acquisition:

Data were obtained from peer-reviewed literature through a search of the PubMed database (1988-2013) as well as from textbook chapters and surgical technique papers.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

The clinical outcomes after revision ACL reconstruction are largely based on level IV case series. Much of the existing literature is heterogenous with regard to patient populations, primary and revision surgical techniques, concomitant ligamentous injuries, and additional procedures performed at the time of the revision, which limits generalizability. Nevertheless, there is a general consensus that the outcomes for revision ACL reconstruction are inferior to primary reconstruction.

Conclusion:

Excellent results can be achieved with regard to graft stability, return to play, and functional knee instability but are generally inferior to primary ACL reconstruction. A staged approach with autograft reconstruction is recommended in any circumstance in which a single-stage approach results in suboptimal graft selection, tunnel position, graft fixation, or biological milieu for tendon-bone healing.

Strength-of-Recommendation Taxonomy (SORT):

Good results may still be achieved with regard to graft stability, return to play, and functional knee instability, but results are generally inferior to primary ACL reconstruction: Level B.

Biomechanical evaluation of the quadriceps tendon autograft for anterior cruciate ligament reconstruction: a cadaveric study

BACKGROUND

Recently, many surgeons have chosen the quadriceps tendon (QT) as an autograft for anterior cruciate ligament (ACL) reconstruction. However, there have not been biomechanical studies that quantitatively evaluated knee function after reconstruction using a QT autograft.

PURPOSE

To measure the 6 degrees of freedom knee kinematics and in situ graft forces after reconstruction with a QT autograft compared with a quadrupled semitendinosus and gracilis (QSTG) tendon autograft.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ten human cadaveric knees (age, 54-64 years) were tested in 3 conditions: (1) intact, (2) ACL deficient, and (3) after ACL reconstruction using a QT or QSTG autograft. With use of a robotic/universal force-moment sensor testing system, knee kinematics and in situ forces in the ACL and autografts were obtained at 5 knee flexion angles under externally applied loads: (1) 134-N anterior tibial load, (2) 134-N anterior tibial load with 200-N axial compression, and (3) 10-N·m valgus and 5-N·m internal tibial torque.

RESULTS

Under the anterior tibial load, both autografts restored anterior tibial translation to within 2.5 mm of the intact knee and in situ forces to within 20 N of the intact ACL at 15°, 30°, and 60°. Adding compression did not change these findings. With the combined rotatory load, the anterior tibial translation and graft in situ forces were again not significantly different from the intact ACL. There were no significant differences between the grafts under any experimental condition.

CONCLUSION

Reconstruction of the ACL with a QT autograft restored knee function to similar levels as that reconstructed with a QSTG autograft under loads simulating clinical examinations.

CLINICAL RELEVANCE

The positive biomechanical results of this cadaveric study lend support to the use of a QT autograft for ACL reconstruction, as it could restore knee function immediately after surgery under applied loads that mimic clinical examinations.

Combined effects of chemical priming and mechanical stimulation on mesenchymal stem cell differentiation on nanofiber scaffolds

Functional tissue engineering of connective tissues such as the anterior cruciate ligament (ACL) remains a significant clinical challenge, largely due to the need for mechanically competent scaffold systems for grafting, as well as a reliable cell source for tissue formation. We have designed an aligned, polylactide-co-glycolide (PLGA) nanofiber-based scaffold with physiologically relevant mechanical properties for ligament regeneration. The objective of this study is to identify optimal tissue engineering strategies for fibroblastic induction of human mesenchymal stem cells (hMSC), testing the hypothesis that basic fibroblast growth factor (bFGF) priming coupled with tensile loading will enhance hMSC-mediated ligament regeneration. It was observed that compared to the unloaded, as well as growth factor-primed but unloaded controls, bFGF stimulation followed by physiologically relevant tensile loading enhanced hMSC proliferation, collagen production and subsequent differentiation into ligament fibroblast-like cells, upregulating the expression of types I and III collagen, as well as tenasin-C and tenomodulin. The results of this study suggest that bFGF priming increases cell proliferation, while mechanical stimulation of the hMSCs on the aligned nanofiber scaffold promotes fibroblastic induction of these cells. In addition to demonstrating the potential of nanofiber scaffolds for hMSC-mediated functional ligament tissue engineering, this study yields new insights into the interactive effects of chemical and mechanical stimuli on stem cell differentiation.

Bone-patellar tendon-bone autograft versus allograft in outcomes of anterior cruciate ligament reconstruction: a meta-analysis of 5182 patients

BACKGROUND

Bone-patellar tendon-bone (BPTB) is a common autograft and allograft source used for anterior cruciate ligament (ACL) reconstruction. Although the failure rate is generally higher for allografts, donor site morbidity and anterior knee pain can be issues with BPTB autografts. Controversy exists regarding the functional outcomes, complications, and knee stability of these grafts, previous comparisons of which have been based on smaller samples of case series.

PURPOSE

To compare BPTB autografts to allografts for ACL reconstruction, specifically with regard to patient satisfaction, return to preinjury activity level, and postoperative functional outcomes.

STUDY DESIGN

Meta-analysis.

METHODS

A total of 76 studies published between 1998 and 2012, including a total of 5182 patients, were reviewed. It was not required for studies to be comparative in nature. Outcomes evaluated were graft rupture rate, return to preinjury activity level, overall and subjective International Knee Documentation Committee (IKDC), Lysholm, Tegner activity, Cincinnati Knee Rating System, pivot shift, and single-legged hop tests, as well as KT-1000 arthrometer side-to-side difference and presence of anterior knee pain. Summary odds ratios with 95% confidence intervals were calculated to compare BPTB autografts to allografts for each outcome.

RESULTS

Outcomes on subjective IKDC, Lysholm, Tegner, single-legged hop, and KT-1000 arthrometer were statistically significantly in favor of autografts. Return to preinjury activity level, overall IKDC, pivot shift, and anterior knee pain were significantly in favor of allografts, although allograft BPTB demonstrated a 3-fold increase in rerupture rates compared with autograft (12.7% vs 4.3%). There was no significant difference between the 2 groups for Cincinnati Knee scores.

CONCLUSION

Patients undergoing ACL reconstruction with BPTB autografts demonstrate lower rates of graft rupture, lower levels of knee laxity, and improved single-legged hop test results and are more generally satisfied postoperatively compared with patients undergoing reconstruction with allograft BPTB.

Age, graft size, and Tegner activity level as predictors of failure in anterior cruciate ligament reconstruction with hamstring autograft

BACKGROUND

Patient age, Tegner activity level, and graft size could be factors that influence the outcome of anterior cruciate ligament reconstruction (ACLR) with hamstring autografts.

HYPOTHESIS

Decreased graft size, higher Tegner activity score, and younger age are associated with an increased failure rate of ACLR, represented by continued knee laxity and revision surgery.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 98 patients who had undergone ACLR with hamstring tendon autografts between 2000 and 2007 were identified from a computerized relational database. Inclusion criteria consisted of a minimum of 2 years of follow-up, all age groups, and all activity levels. Exclusion criteria consisted of treatment with other grafts or previous ligament surgery, previous ACL repairs, bilateral ACL injuries, and associated ligament tears. Failure was defined as a 2+ Lachman result, positive pivot shift, and 5-mm difference or more on KT-1000 arthrometer measurement.

RESULTS

Fifteen of the 98 ACLRs (15.3%) were defined as failures. Of the failures, 12 of 48 (25%) occurred in patients aged 25 years and younger, whereas 3 of 50 (6%) occurred in patients older than 25 years. There was a statistically significant association when comparing failure rate and age groups (P = .009); however, a significant association was not found between graft size and failure rate in the entire study population (P = .135) or within the different age groups (age ≤25 years vs. >25 years) based on failure rate (P = .390 and P = .165, respectively). No statistical significance was found when Tegner activity level and failure rate were compared in the overall study population (P = .463) or within age groups (≤25 years, P = .707; >25 years, P = .174).

CONCLUSION

In this study population, younger patients (≤25 years) demonstrated a higher failure rate compared with the over-25 age group. A statistically significant difference was not found in terms of graft size and activity level correlating with failure rate in ACL reconstruction with hamstring autograft.

Technique of anatomical footprint reconstruction of the ACL with oval tunnels and medial portal aimers

PURPOSE

The purpose of this article was to demonstrate an anterior cruciate ligament (ACL) reconstruction technique using oval tunnels. Aim of this single bundle technique is to fit the footprint anatomy of the ACL as closely as possible. TECHNIQUE AND PATIENTS: The presented technique is a single bundle technique using a semitendinosus graft. For femoral tunnel placement, a specific medial portal aimer (Karl Storz, Tuttlingen, Germany) is used. Aiming and drilling of the femoral tunnel are performed via the medial portal. Oval tunnels are created by stepwise dilatation with ovally shaped dilatators. The position of the femoral tunnel is visualized and controlled with the arthroscope via the medial portal. For the tibial tunnel placement, a specific aimer was used as well. With this technique, 24 patients were operated and all intra- and postoperative complications were analyzed prospectively. The tunnel position was documented postoperatively by CT scan.

RESULTS

There were no significant intra- and postoperative complications associated with the oval tunnel technique. The postoperative 3D CT scan revealed that all femoral and tibial tunnels were located within the area of the anatomical ACL insertions.

CONCLUSIONS

This article presents an ACL reconstruction technique using oval dilatators and medial portal aimers to create oval tunnels. These oval tunnels match the insertion site anatomy much closer than round tunnels do.

LEVEL OF EVIDENCE

Level IV, case series.

Preoperative predictors for noncopers to pass return to sports criteria after ACL reconstruction

Less than 50% of athletes pass criteria to return to sports (RTS) 6 months after ACL reconstruction (ACLR). Using data on 38 noncopers, we hypothesized that preoperative age, quadriceps strength index (QI), and knee flexion moments (KFM) during gait would predict the ability to pass/fail RTS criteria and that preoperative quadriceps strength gains would be predictive of passing RTS criteria. Gait analysis and strength data were collected before and after a preoperative intervention and 6 months after ACLR. Age, QI, and KFM each contributed to the predictability to pass or fail RTS criteria 6 months after ACLR. Collectively, the variables predict 69% who would pass and 82% who would fail RTS criteria 6 months after ACLR. Younger athletes who have symmetrical quadriceps strength and greater KFM were more likely to pass RTS criteria. Further, 63% of those who increased preoperative quadriceps strength passed RTS criteria, whereas 73% who did not failed. Increasing quadriceps strength in noncopers before ACLR seems warranted.

Two-year outcome with the AperFix system for ACL reconstruction

The purpose of the study was to assess the fixation durability of the AperFix System (Cayenne Medical, Inc, Scottsdale, Arizona) used in arthroscopic reconstruction of the anterior cruciate ligament. The AperFix System consists of a femoral and tibial component designed to secure either allograft or autograft. The outcomes of 185 knees (180 patients) were retrospectively reviewed at a minimum of 2 years postoperatively. Mean age at surgery was 31±12 years (range, 16-68 years). Of these, a convenience sample was seen prospectively to obtain radiographs and to assess functional status. No cases occurred of fixation failure involving loss of graft positioning or pullout. No patients required revision anterior cruciate ligament reconstruction. In 2 knees, the tip of the central fixation pin had to be modified as a result of hardware prominence and soft tissue irritation at 434 and 159 days postoperatively, respectively. In 4 knees, tibial screw removal occurred secondary to local discomfort (mean, 239 days; range, 105-371 days). No other recurring adverse events or problems associated with the implants were identified. Forty-four patients were evaluated prospectively at a mean follow-up of 32±7 months. Lysholm scores and patient satisfaction scores were positively and significantly correlated with Tegner activity scores (r=0.61; P<.0001). Eighty-two (82%) patients had a KT-1000 (Medmetric Corp, San Diego, California) side-to-side difference of less than 3 mm (average, 0.4 mm). No indications of femoral device migration existed when comparing follow-up and immediate postoperative radiographs. The AperFix System provides durable femoral aperture fixation during anterior cruciate ligament reconstruction with excellent clinical outcome scores and a low complication rate.

Growth factors and stem cells for the management of anterior cruciate ligament tears

The anterior cruciate ligament (ACL) is fundamental for the knee joint stability. ACL tears are frequent, especially during sport activities, occurring mainly in young and active patients. Nowadays, the gold standard for the management of ACL tears remains the surgical reconstruction with autografts or allografts. New strategies are being developed to resolve the problems of ligament grafting and promote a physiological healing process of ligamentous tissue without requiring surgical reconstruction. Moreover, these strategies can be applicable in association surgical reconstruction and may be useful to promote and accelerate the healing process. The use of growth factors and stem cells seems to offer a new and fascinating solution for the management of ACL tears. The injection of stem cell and/or growth factors in the site of ligamentous injury can potentially enhance the repair process of the physiological tissue. These procedures are still at their infancy, and more in vivo and in vitro studies are required to clarify the molecular pathways and effectiveness of growth factors and stem cells therapy for the management of ACL tears. This review aims to summarize the current knowledge in the field of growth factors and stem cells for the management of ACL tears.

Relation between anterior cruciate ligament graft obliquity and knee laxity in elite athletes at the National Football League combine

PURPOSE

The purposes of this study were to determine the incidence of vertical anterior cruciate ligament (ACL) reconstructions in elite athletes and to determine whether graft obliquity correlates with knee stability in this population.

METHODS

One hundred thirty-seven knees in 125 athletes at the 2005-2009 National Football League Combine were identified as having had previous ACL reconstructions. The graft type, fixation, and physical examination findings were recorded for each athlete. Graft obliquity was measured by previously described methods based on plain radiography and magnetic resonance imaging (MRI). Radiographic measurements included tibial tunnel and femoral tunnel locations, as well as a sum of these tunnel positions on the lateral radiograph (sum score). MRI measurements included sagittal and coronal ACL angles and the ACL-Blumensaat line angle. The relation of graft obliquity to physical examination findings was assessed.

RESULTS

Sixty-four percent of knees had vertical grafts based on radiography and 35% based on MRI criteria. The average tibial tunnel location on radiography was 33% from the anterior tibial plateau in the oblique group compared with 42% in the vertical group (P < .0001). Knees with a sum score of 66 or less, tibial tunnel 37% or less from the anterior tibial plateau, and sagittal obliquity of 60° or less were less likely to have increased translation on the Lachman examination than knees with a sum score greater than 66, tibial tunnel greater than 37% from the anterior tibial plateau, and sagittal obliquity greater than 60° (P < .05).

CONCLUSIONS

There was a wide range of ACL graft obliquity in the examined cohort of elite athletes who continued to perform at high levels. Less oblique (more vertical) grafts were associated with greater anterior tibial translation on Lachman testing. ACL graft obliquity, which is particularly sensitive to tibial tunnel placement, can influence knee stability.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

An extra-articular procedure improves the clinical outcome in anterior cruciate ligament reconstruction with hamstrings in female athletes

PURPOSE

A positive glide is a common finding after ACL reconstructions, especially in women. The aim of this study was to prospectively evaluate the role of Cocker-Arnold's extra-articular procedure in reducing the incidence of a residual postoperative rotational knee laxity.

METHODS

Sixty patients affected by an ACL injury with a +2 (clunk) or +3 (gross shift) pivot-shift test entered this prospective study; they were randomly assigned to group A (control group, hamstrings) or group B (study group, hamstrings plus Cocker-Arnold). Thirty-two patients entered group A and 28 group B. At follow-up, patients underwent clinical evaluation, KT-1000 arthrometer and Lysholm, Tegner, VAS and subjective and objective IKDC form.

RESULTS

At a mean follow-up of 44.6 months, the same expert surgeon reviewed 55 patients (28 group A and 27 group B). The comparison of the results of the evaluation scales used and of the KT-1000 arthrometer did not show statistically significant differences (p>0.05). Lachman test was negative (S/S) in all the patients of both groups (100 %). A residual positive pivot-shift (glide) was found in 16 patients (57.1 %) of group A and in five patients (18.6 %) of group B (p<0.05).

CONCLUSIONS

The extra-articular MacIntosh procedure modified by Cocker-Arnold in combination with ACL reconstruction significantly reduces the rotational instability of the knee.

Graft size and patient age are predictors of early revision after anterior cruciate ligament reconstruction with hamstring autograft

PURPOSE

To evaluate whether decreased hamstring autograft size and decreased patient age are predictors of early graft revision.

METHODS

Of 338 consecutive patients undergoing primary anterior cruciate ligament (ACL) reconstruction with hamstring autograft, 256 (75.7%) were evaluated. Graft size and patient age, gender, and body mass index at the time of ACL reconstruction were recorded, along with whether subsequent ACL revision was performed.

RESULTS

The 256 patients comprised 136 male and 120 female patients and ranged in age from 11 to 52 years (mean, 25.0 years). The mean follow-up was 14 months (range, 6 to 47 months). Revision ACL reconstruction was performed in 18 of 256 patients (7.0%) at a mean of 12 months after surgery (range, 3 to 31 months). Revision was performed in 1 of 58 patients (1.7%) with grafts greater than 8 mm in diameter, 9 of 139 patients (6.5%) with 7.5- or 8-mm-diameter grafts, and 8 of 59 patients (13.6%) with grafts 7 mm or less in diameter (P = .027). There was 1 revision performed in the 137 patients aged 20 years or older (0.7%), but 17 revisions were performed in the 119 patients aged under 20 years (14.3%) (P < .0001). Most revisions (16 of 18) were noted to occur in patients aged under 20 years with grafts 8 mm in diameter or less, and the revision rate in this population was 16.4% (16 of 97 patients). Age less than 20 years at reconstruction (odds ratio [OR], 18.97; 95% confidence interval [CI], 2.43 to 147.06; P = .005), decreased graft size (OR, 2.20; 95% CI, 1.00 to 4.85; P = .05), and increased follow-up time (OR, 1.07; 95% CI, 1.02 to 1.12) were associated with increased risk of revision.

CONCLUSIONS

Decreased hamstring autograft size and decreased patient age are predictors of early graft revision. Use of hamstring autografts 8 mm in diameter or less in patients aged under 20 years is associated with higher revision rates.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Tissue engineering strategies in ligament regeneration

Ligaments are dense fibrous connective tissues that connect bones to other bones and their injuries are frequently encountered in the clinic. The current clinical approaches in ligament repair and regeneration are limited to autografts, as the gold standard, and allografts. Both of these techniques have their own drawbacks that limit the success in clinical setting; therefore, new strategies are being developed in order to be able to solve the current problems of ligament grafting. Tissue engineering is a novel promising technique that aims to solve these problems, by producing viable artificial ligament substitutes in the laboratory conditions with the potential of transplantation to the patients with a high success rate. Direct cell and/or growth factor injection to the defect site is another current approach aiming to enhance the repair process of the native tissue. This review summarizes the current approaches in ligament tissue engineering strategies including the use of scaffolds, their modification techniques, as well as the use of bioreactors to achieve enhanced regeneration rates, while also discussing the advances in growth factor and cell therapy applications towards obtaining enhanced ligament regeneration.

Anterior cruciate ligament graft failure: a comparison of graft type based on age and Tegner activity level

BACKGROUND

When reviewing anterior cruciate ligament instability, age, gender, activity level, associated injury, and type of graft should all be considered.

HYPOTHESIS

The authors hypothesized that patients under 25 years of age will have higher failure rates with anterior cruciate ligament reconstruction than those older than 25 years, and that in the patients younger than 25 years, bone-patellar tendon-bone autograft will have the lowest failure rate.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

With use of a computerized relational database, all patients having primary anterior cruciate ligament reconstruction at 1 institution between January 2000 and July 2007 with allograft, bone-patellar tendon-bone, and hamstring grafts were evaluated.

RESULTS

A significant association was found between age group and graft failure (P = .012). Patients 25 years and younger had a significantly higher failure rate (16.5%) than patients older than 25 years (8.3%). Pairwise comparisons indicated that both allograft (29.2%) and semitendinosus/gracilis (25.0%) grafts resulted in significantly higher failure rates than bone-patellar tendon-bone grafts (11.8%) in the age group of patients 25 years and younger.

CONCLUSION

Autograft hamstrings and allografts had a significantly higher failure rate in the age group of patients 25 years and younger compared with the bone-patellar tendon-bone autograft. These data suggest that bone-patellar tendon-bone autografts may be a better graft source for young, active individuals.

Regeneration and repair of tendon and ligament tissue using collagen fibre biomaterials

Collagen fibres are ubiquitous macromolecular assemblies in nature, providing the structures that support tensile mechanical loads within the human body. Aligned type I collagen fibres are the primary structural motif for tendon and ligament, and therefore biomaterials based on these structures are considered promising candidates for mediating regeneration of these tissues. However, despite considerable investigation, there remains no collagen-fibre-based biomaterial that has undergone clinical evaluation for this application. Recent research in this area has significantly enhanced our understanding of these complex and challenging biomaterials, and is reinvigorating interest in the development of such structures to recapitulate mechanical function. In this review we describe the progress to date towards a ligament or tendon regeneration template based on collagen fibre scaffolds. We highlight reports of particular relevance to the development of the underlying biomaterials science in this area. In addition, the potential for tailoring and manipulating the interactions between collagen fibres and biological systems, as hybrid biomaterial-biological ensembles, is discussed in the context of developing novel tissue engineering strategies for tendon and ligament.

Pre-operative versus post-operative gait variability in patients with acute anterior cruciate ligament deficiency

Change in gait variability at least 6 months after surgical reconstruction of the anterior cruciate ligament (ACL) was assessed in 20 male patients with acute ACL deficiency and compared with pre-operative data and that from 20 healthy male controls. Gait was measured using a triaxial accelerometer and data were analysed by the Gait Evaluation Differential Entropy Method (GEDEM) to determine gait variability. Pain was assessed with a visual analogue scale and functional ability with the Oswestry Disability Index and the International Knee Documentation Committee score. Mean gait variability was significantly lower after than before surgery, with values for the anterior-posterior axis being in the normal range of controls after 6 months, whereas in the mediolateral axis mean gait variability remained significantly higher, indicating that some rotational instability remained in the time-frame of the study. Pain and functional ability scores improved after surgery compared with before surgery. The combination of accelerometry and GEDEM may be a useful orthopaedic tool for the post-operative evaluation of patients who have undergone ACL reconstruction.

Arthroscopically pertinent landmarks for tunnel positioning in single-bundle and double-bundle anterior cruciate ligament reconstructions

BACKGROUND

Quantification of the overall anterior cruciate ligament (ACL) and anteromedial (AM) and posterolateral (PL) bundle centers in respect to arthroscopically pertinent bony and soft tissue landmarks has not been thoroughly assessed.

HYPOTHESIS

A standardized anatomical measurement method can quantitate the locations of the ACL and AM and PL bundle centers in reference to each other and anatomical landmarks.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Quantification of the ACL and its bundle attachments was performed on 11 cadaveric knees using a radio frequency-tracking device.

RESULTS

The tibial ACL attachment center was 7.5 mm medial to the anterior horn of the lateral meniscus, 13.0 mm anterior to the retro-eminence ridge, and 10.5 mm posterior to the ACL ridge. The femoral ACL attachment center was 1.7 mm proximal to the bifurcate ridge and 6.1 mm posterior to the lateral intercondylar ridge. The tibial AM attachment center was 8.3 mm medial to the anteromedial aspect of the lateral meniscus anterior horn, 17.8 mm anterior to the retro-eminence ridge, and 5.6 mm posterior to the ACL ridge. The femoral AM attachment center was 4.8 mm proximal to the bifurcate ridge and 7.1 mm posterior to the lateral intercondylar ridge. The tibial PL bundle attachment center was 6.6 mm medial to the posteromedial aspect of the lateral meniscus anterior horn, 10.8 mm anteromedial to the root attachment of the lateral meniscus posterior horn, and 8.4 mm anterior to the retro-eminence ridge. The femoral PL bundle attachment center was 5.2 mm distal to the bifurcate ridge and 3.6 mm posterior to the lateral intercondylar ridge.

CONCLUSION

The authors developed a comprehensive compilation of measurements of arthroscopically pertinent bony and soft tissue landmarks that quantitate the ACL and its individual bundle attachment centers on the tibia and femur.

CLINICAL RELEVANCE

These clinically relevant arthroscopic landmarks may enhance single- and double-bundle ACL reconstructions through improved tunnel placement.