Intraarticular rupture pattern of the ACL

Comparing MRI and arthroscopic appearances of common knee pathologies: A pictorial review

Knee pathology, including anterior cruciate ligament (ACL) tears, meniscal tears, articular cartilage lesions, and intra-articular masses or cysts are common clinical entities treated by orthopedic surgeons with arthroscopic surgery. Preoperatively, magnetic resonance imaging (MRI) is now standard in confirming knee pathology, particularly detecting pathology less evident with history and physical examination alone. The radiologist's MRI interpretation becomes essential in evaluating intra-articular knee structures. Typically, the radiologist that interprets the MRI does not have the opportunity to view the same pathology arthroscopically. Thus, the purpose of this article is to illustratively reconcile what the orthopedic surgeon sees arthroscopically with what the radiologist sees on magnetic resonance imaging when viewing the same pathology. Correlating virtual and actual images can help better understand pathology, resulting in more accurate MRI interpretations. In this article, we present and review a series of MR and correlating arthroscopic images of ACL tears, meniscal tears, chondral lesions, and intra-articular masses and cysts. Short teaching points are included to highlight the importance of radiological signs and pathological MRI appearance with significant clinical and arthroscopic findings.

Diagnostic accuracy of lever sign test in acute and chronic ACL injuries

Introduction

The anterior cruciate ligament (ACL) is a commonly affected knee ligament prone to frequent injuries. Henceforth, we aimed to determine the diagnostic accuracy of lever sign test in Acute and chronic ACL injuries.

Method

At the institution's initial outpatient visit, 150 consecutive patients (92 males and 58 females) were evaluated. Total 108 patients had injury in their right leg, whereas 42 had injury in their left leg. Based on time since injury, the patients were divided into Acute and chronic groups. Clinical examinations (lachman's test and lelli's test) of all patients were confirmed with arthroscopic findings and compared between the two groups.

Results

In the acute ACL injury, the lever test had a kappa value 0.704. The accuracy and sensitivity of the Lachman, anterior drawer, pivot shift, and lever tests were calculated. We found that the lever test had the highest accuracy and sensitivity (85.48 %, 91.18 %) than the rest. In the chronic ACL injury, the kappa value for the results of the Lachman test evaluation was 0.723. The chronic ACL injuries accuracy and sensitivity values for the Lachman (86.36 %, 91.67 %), anterior drawer (76.14 %, 81.25 %), pivot shift (55.68 %, 58.49 %), and lever tests were determined.

Conclusion

The lever sign test is more accurate and reliable in the acute ACL injuries, while the Lachman test is more accurate and reliable in the chronic ACL injuries.

Remnant-Sparing Anterior Cruciate Ligament Reconstruction Results in Similar Clinical, Functional, and Quality-of-Life Outcomes to Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction

Purpose

To compare a large cohort of patients who underwent remnant-sparing anterior cruciate ligament reconstruction (rACLR) with a matched group of patients who underwent anatomic single-bundle anterior cruciate ligament reconstruction (ACLR) with respect to clinical laxity, patient-reported outcomes, and functional testing.

Methods

Patients who underwent rACLR between January 2010 and December 2015 were matched according to age, sex, body mass index, and graft type to patients who underwent ACLR. The primary outcome measure was the ACL Quality of Life (ACL-QOL) score at final follow-up of 24 months. Secondary outcomes included functional tests and clinical laxity measurements at 6, 12, and 24 months postoperatively. Concurrent intra-articular pathology at the time of surgery and postoperative complications were also recorded. Statistical analyses included the dependent t test and the Wilcoxon signed rank test.

Results

A total of 210 rACLR patients were successfully matched to a corresponding cohort of 210 ACLR patients. There were no statistically significant differences in ACL Quality of Life (ACL-QOL) or functional testing results between the groups; however, scores in both groups showed a steady and statistically significant improvement over time. A statistically significant difference was noted with respect to the Lachman test findings, favoring the rACLR cohort (Z = -2.79, P = .005); no between-group difference was seen for the pivot-shift test (Z = -0.36, P = .72). The rACLR group had a significantly lower rate of concurrent meniscal and chondral injury. There was no difference in complications between the groups (Z = -0.49, P = .63).

Conclusions

There was no difference in patient-reported or functional testing outcomes in patients undergoing remnant-sparing compared with anatomic single-bundle ACLR. There was, however, a significantly lower rate of positive Lachman test findings after rACLR. Furthermore, the rate of concurrent meniscal and chondral pathology was lower in the rACLR group.

Level of Evidence

Level III, retrospective cohort study.

Fatigue-driven compliance increase and collagen unravelling in mechanically tested anterior cruciate ligament

Approximately 300,000 anterior cruciate ligament (ACL) tears occur annually in the United States, half of which lead to the onset of knee osteoarthritis within 10 years of injury. Repetitive loading is known to result in fatigue damage of both ligament and tendon in the form of collagen unravelling, which can lead to structural failure. However, the relationship between tissue's structural, compositional, and mechanical changes are poorly understood. Herein we show that repetitive submaximal loading of cadaver knees causes an increase in co-localised induction of collagen unravelling and tissue compliance, especially in regions of greater mineralisation at the ACL femoral enthesis. Upon 100 cycles of 4× bodyweight knee loading, the ACL exhibited greater unravelled collagen in highly mineralized regions across varying levels of stiffness domains as compared to unloaded controls. A decrease in the total area of the most rigid domain, and an increase in the total area of the most compliant domain was also found. The results highlight fatigue-driven changes in both protein structure and mechanics in the more mineralized regions of the ACL enthesis, a known site of clinical ACL failure. The results provide a starting point for designing studies to limit ligament overuse injury.

Clinical Reproducibility and Reliability of Lever Sign (Lelli's) Test for Acute ACL Tear Performed by Medical Students

BACKGROUND

Injuries to the anterior cruciate ligament (ACL) in sports are frequent in children and young adults participating in sporting activities involving rotational and pivoting movements. Magnetic resonance imaging is the most accurate diagnostic tool to detect an ACL tear. There are, however, a number of specialized tests available to assess ACL competency.

HYPOTHESIS

A novel test was described with extremely high clinical accuracy. The purpose of this study was to assess its clinical accuracy when performed by non-orthopedic providers, such as medical students.

METHODS

A cross-sectional study design was adopted, and two patients with an MRI-proven complete ACL tear were selected. One patient was thin, and the other was overweight, and both were examined by 100 medical students for both the injured and uninjured knee. The results for these exams were recorded, and a statistical analysis of the screening test was done to evaluate the new special test.

RESULTS

Our results were different from the ones found in the literature: we found the test to have a significantly lower performance in terms of sensitivity, specificity, and positive and negative likelihood ratios compared to the literature numbers.

CONCLUSION

The Lever sign (Lelli's) test loses clinical credibility and significance when performed by non-orthopedic providers or doctors, such as medical students in our study.

Loading mechanisms of the anterior cruciate ligament

This review identifies the three-dimensional knee loads that have the highest risk of injuring the anterior cruciate ligament (ACL) in the athlete. It is the combination of the muscular resistance to a large knee flexion moment, an external reaction force generating knee compression, an internal tibial torque, and a knee abduction moment during a single-leg athletic manoeuvre such as landing from a jump, abruptly changing direction, or rapidly decelerating that results in the greatest ACL loads. While there is consensus that an anterior tibial shear force is the primary ACL loading mechanism, controversy exists regarding the secondary order of importance of transverse-plane and frontal-plane loading in ACL injury scenarios. Large knee compression forces combined with a posteriorly and inferiorly sloped tibial plateau, especially the lateral plateau-an important ACL injury risk factor-causes anterior tibial translation and internal tibial rotation, which increases ACL loading. Furthermore, while the ACL can fail under a single supramaximal loading cycle, recent evidence shows that it can also fail following repeated submaximal loading cycles due to microdamage accumulating in the ligament with each cycle. This challenges the existing dogma that non-contact ACL injuries are predominantly due to a single manoeuvre that catastrophically overloads the ACL.

ACL Graft Matching: Cadaveric Comparison of Microscopic Anatomy of Quadriceps and Patellar Tendon Grafts and the Femoral ACL Insertion Site

BACKGROUND

The optimal graft choice between the bone-patellar tendon-bone (BPTB) and the quadriceps tendon remains controversial. Studies evaluating the microscopic anatomy of the quadriceps tendon-patellar bone (QTB) and BPTB grafts for anterior cruciate ligament (ACL) reconstruction are currently lacking.

HYPOTHESIS

The relationship between post-ACL reconstruction graft bending angle (GBA) and the angle corresponding to the GBA (cGBA) would indicate that the BPTB can bend more than the QTB at the femoral tunnel aperture.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty paired human cadaveric knees fixed at <10° of knee joint flexion (mean age, 82.5 years) underwent histological sectioning and staining with Masson trichrome and toluidine blue. The femoral ACL insertion, QTB graft, and BPTB graft were microscopically analyzed. The width of the direct insertion, thickness of the uncalcified fibrocartilage and calcified fibrocartilage, ligament attachment angle, and cGBA for each group were measured. Eighteen patients who underwent ACL reconstruction with QTB or BPTB autograft were included for the evaluation of GBA using computed tomography images at 1 week postoperatively.

RESULTS

The mean insertion widths of the femoral ACL, QTB, and BPTB were 7.81, 9.07, and 6.54 mm, respectively. The QTB was 16% wider than the ACL, while the BPTB was 16% narrower than the ACL. The mean insertion thicknesses of the femoral ACL, QTB, and BPTB were 0.53, 0.94, and 0.38 mm, respectively. The QTB was 77% thicker than the ACL (P < .001), while the BPTB was 28% thinner than the ACL (P = .017). The mean ligament attachment angles of the femoral ACL, QTB, and BPTB were 20.3°, 30.2°, and 33.3°, respectively, and the QTB and the BPTB were 49% and 64% larger, respectively, than the ACL. The mean cGBAs of the femoral ACL, QTB, and BPTB were 33.9°, 35.1°, and 12.3°, respectively. The BPTB was 64% smaller than the ACL, while there was no significant difference between the QTB and the ACL. The mean GBA was 57.7°.

CONCLUSION

The insertion width and thickness were significantly greater and smaller in the QTB and BPTB grafts, respectively, than in the ACL. The relationship between GBA after ACL reconstruction and cGBA in knee extension indicates that at the femoral tunnel aperture, the BPTB can bend more than the QTB.

CLINICAL RELEVANCE

QTB graft may allow more anatomic ACL reconstruction to be performed.

Selective bundle versus complete anterior-cruciate ligament reconstruction: A systematic review and meta-analysis

Purpose

Selective bundle reconstruction (SLB) refers to preservation of the intact bundle and reconstruction of the ruptured bundle in a partial tear while complete ACL reconstruction involves the removal of all remnant tissue and reconstruction of one or both bundles. As the evidence for SLB versus complete ACL reconstruction remains unclear, this study aimed to compare the two techniques. This study's hypothesis was that SLB reconstruction allows better function and stability compared to complete ACL reconstruction.

Methods

A systematic search of PubMed, EMBASE, Scopus and Cochrane Library was conducted, identifying studies that compared SLB ('selective' group) versus complete ('complete' group) ACL reconstruction. Meta-analysis was conducted for post-operative functional scores, stability outcomes and complications as well as pre-operative to post-operative change.

Results

Eleven studies were included in the meta-analysis, with 1107 patients and a pooled mean follow-up of 29.5 months. Post-operatively, the Selective group had significantly reduced anterior laxity, shown by a lower mean arthrometry side-to-side difference (p<0.01). Analysis of change results showed that the Selective group had a lower mean improvement in arthrometry side-to-side difference as well (p<0.01). No significant difference was shown for all other post-operative outcomes.

Conclusion

This study provides valuable insight to the management of partial tears. It has demonstrated that the preservation of the intact bundle offers stability and function that is as good as complete reconstruction and that SLB is a potentially viable option in the management of partial tears.

Level of evidence

Meta-analysis; Level of evidence, 4.

Prevalence of anterolateral ligament injuries and lateral meniscus tear on MR imaging in patients with both-bundle tear vs. selective bundle incomplete tear of the anterior cruciate ligament

OBJECTIVES

We investigated the prevalence of anterolateral ligament (ALL) injury and lateral meniscus (LM) tear in cases with both-bundle tear and selective bundle incomplete tear of the anterior cruciate ligament (ACL).

METHODS

A total of 174 cases of magnetic resonance (MR) images that had an ACL tear and underwent arthroscopic ACL reconstruction were retrospectively reviewed. ACL injury was classified into both bundle, anteromedial bundle, and posterolateral bundle (PL) on arthroscopic finding. The ALL was divided into three portions: femoral, meniscal, and tibial. ALL injury was scored into three groups: grade 0 is intact; grade 1 is stranding and edema surrounds the expected location of the ALL; grade 2 is clear discontinuity of the ALL consistent with rupture. Traumatic LM tear was also assessed on MR images.

RESULTS

The total prevalence of ALL injury was 36.2% (reader 1) and 42.0% (reader 2). ALL injury was statistically related to the selective bundle tear (p = 0.002 and 0.004, readers 1 and 2). PL bundle tear was significantly correlated with the ALL injury (p value < 0.001, readers 1 and 2, both). The location and grade of ALL injury were not significantly correlated with the type of ACL injury. LM tear was not significantly related to the types of ACL tear (p = 0.208 and 0.907, readers 1 and 2) and ALL injury (p value = 0.096 and 0.383, readers 1 and 2).

CONCLUSIONS

ALL injury was significantly related to the PL bundle tear of the ACL. LM tear was not significantly correlated with the types of ACL injury and ALL injury.

KEY POINTS

• Anterolateral ligament (ALL) injury was significantly related to the posterolateral bundle (PL) tear of the anterior cruciate ligament (ACL). • Lateral meniscus (LM) tear was not significantly correlated with the types of ACL injury and ALL injury. • Clinicians and radiologists should be aware of these relationships and scrutinize ALL injury in cases with PL bundle tears, even with an incomplete ACL injury.

Pelvic floor muscle injury during a difficult labor. Can tissue fatigue damage play a role?

Pubovisceral muscle (PVM) injury during a difficult vaginal delivery leads to pelvic organ prolapse later in life. If one could address how and why the muscle injury originates, one might be able to better prevent these injuries in the future. In a recent review we concluded that many atraumatic injuries of the muscle-tendon unit are consistent with it being weakened by an accumulation of passive tissue damage during repetitive loading. While the PVM can tear due to a single overstretch at the end of the second stage of labor we hypothesize that it can also be weakened by an accumulation of microdamage and then tear after a series of submaximal loading cycles. We conclude that there is strong indirect evidence that low cycle fatigue of PVM passive tissue is a possible mechanism of its proximal failure. This has implications for finding new ways to better prevent PVM injury in the future.

Injuries in Muscle-Tendon-Bone Units: A Systematic Review Considering the Role of Passive Tissue Fatigue

Background:

Low-cycle fatigue damage accumulating to the point of structural failure has been recently reported at the origin of the human anterior cruciate ligament under strenuous repetitive loading. If this can occur in a ligament, low-cycle fatigue damage may also occur in the connective tissue of muscle-tendon units. To this end, we reviewed what is known about how, when, and where injuries of muscle-tendon units occur throughout the body.

Purpose:

To systematically review injuries in the muscle-tendon-bone complex; assess the site of injury (muscle belly, musculotendinous junction [MTJ], tendon/aponeurosis, tendon/aponeurosis–bone junction, and tendon/aponeurosis avulsion), incidence, muscles and tendons involved, mechanism of injury, and main symptoms; and consider the hypothesis that injury may often be consistent with the accumulation of multiscale material fatigue damage during repetitive submaximal loading regimens.

Methods:

PubMed, Web of Science, Scopus, and ProQuest were searched on July 24, 2019. Quality assessment was undertaken using ARRIVE, STROBE, and CARE (Animal Research: Reporting In Vivo Experiments, Strengthening the Reporting of Observational Studies in Epidemiology, and the Case Report Statement and Checklist, respectively).

Results:

Overall, 131 studies met the inclusion criteria, including 799 specimens and 2,823 patients who sustained 3,246 injuries. Laboratory studies showed a preponderance of failures at the MTJ, a viscoelastic behavior of muscle-tendon units, and damage accumulation at the MTJ with repetitive loading. Observational studies showed that 35% of injuries occurred in the tendon midsubstance; 28%, at the MTJ; 18%, at the tendon-bone junction; 13%, within the muscle belly and that 6% were tendon avulsions including a bone fragment. The biceps femoris was the most injured muscle (25%), followed by the supraspinatus (12%) and the Achilles tendon (9%). The most common symptoms were hematoma and/or swelling, tenderness, edema and muscle/tendon retraction. The onset of injury was consistent with tissue fatigue at all injury sites except for tendon avulsions, where 63% of the injuries were caused by an evident trauma.

Conclusion:

Excluding traumatic tendon avulsions, most injuries were consistent with the hypothesis that material fatigue damage accumulated during repetitive submaximal loading regimens. If supported by data from better imaging modalities, this has implications for improving injury detection, prevention, and training regimens.

Has platelet-rich plasma any role in partial tears of the anterior cruciate ligament? Prospective comparative study

BACKGROUND

Partial tears of the anterior cruciate ligament (ACL) are frequent, and there is still considerable controversy surrounding their diagnosis, natural history and treatment.

AIM

To examine patient-reported outcomes, physical examination and magnetic resonance imaging (MRI) findings of partial ACL tears treated with an intraarticular injection of platelet-rich plasma (PRP) compared to a control group.

METHODS

From January 2015 to November 2017, consecutive patients from a single institution with partial ACL tears treated nonoperatively were prospectively evaluated. Partial tears were defined as a positive Lachman test with a clear end-point, a negative pivot-shift and less than 3 mm of side-to-side difference using the KT1000 arthrometer. Patients in group 1 were treated with one intraarticular injection of PRP and specific physical therapy protocol. Control group consisted of patients treated only with physical therapy. Prospective analyzed data included physical examination, Tegner activity level and Lysholm and International Knee Documentation Committee scores. Baseline MRI findings and at 6 mo follow-up were reviewed. Failure was defined as those patients with clinical instability at follow-up that required a subsequent ACL reconstruction.

RESULTS

A total of 40 patients where included, 21 treated with PRP injection with a mean follow-up of 25 mo [standard deviation (SD): 3.6] and 19 in the control group with a mean follow-up of 25 mo (SD: 5.68). Overall failure rate was 32.0% (n = 13). No significant differences were observed between groups regarding subjective outcomes, return to sport and failure rate. MRI findings revealed an improvement in the ACL signal in half of the patients of both groups. However, we did not find a significant relationship between MRI findings and clinical outcomes.

CONCLUSION

Overall, 95.0% of patients returned to sports at a mean follow-up of 25 mo. Mean time to return to sports was 4 mo. Out of these patients, almost 30.0% in each group had a new episode of instability and required surgery at a median time of 5 mo in group 1 and 8 mo in group 2. The addition of PRP alone was not sufficient to enhance any of the outcome measures evaluated, including MRI images, clinical evaluation and failure rate.

Primary ACL Repair of a Chronic ACL Femoral Avulsion with 2-Year Clinical and Radiographic Outcomes: A Case Report

CASE

There has been a reemergence of anterior cruciate ligament (ACL) repair. We present the unique case of an ACL repair in a service member with a chronic tear. The patient went on to have a successful outcome with return to full activities without symptoms and functional outcomes scores equal to preinjury levels.

CONCLUSION

This case demonstrates a preserved ACL remnant after an ACL femoral avulsion secondary to scarring to the posterior cruciate ligament. ACL repair can produce excellent outcomes in the right population, and injury chronicity may not necessarily preclude successful repair in the setting of good-quality ACL remnant.

Graft healing after anterior cruciate ligament reconstruction (ACLR)

Anterior cruciate ligament reconstruction (ACLR) is a commonly performed procedure in Orthopaedic sports medicine. With advances in surgical techniques providing better positioning and fixation of the graft, subsequent graft failure to certain extent should be accounted by poor graft healing. Although different biological modulations for enhancement of graft healing have been tried in different clinical and animal studies, complete graft incorporation into bone tunnels and the “ligamentization” of the intra-articular part have not been fully achieved yet. Based on the understanding of graft healing process and its failure mechanism, the purpose of this review is to combine both the known basic science & clinical evidence, to provide a much clearer picture of the obstacle encountered in graft healing, so as to facilitate researchers on subsequent work on the enhancement of ACL graft healing.

Clinical examination of partial ruptures of the anterior cruciate ligament: A retrospective case-control study

BACKGROUND

Anterior drawer test, Lachman test including evaluation of the endpoint, and pivot shift test have been commonly applied clinically in diagnosing anterior cruciate ligament (ACL) injury but how they function in the appraisal of partial ACL tears is less known. The aims of this study were to examine the diagnostic values of the commonly used knee function tests on patients in detecting ACL injury including partial injury patterns, to assess each of the test's predictive values on the specific ACL injury pattern, and to assess if using multiple tests collectively for the diagnosis of the injury could improve diagnostic accuracy.

METHODS

We evaluated 36 consecutive patients who underwent ACL single bundle augmentation surgery. Those patients were matched by gender and age to 36 patients with a complete rupture of the ACL. Data was obtained from the patients' records. The rupture pattern was confirmed by arthroscopy. An examination under anesthesia was routinely performed by two surgeons who were blinded to the rupture pattern prior to surgery.

RESULTS

Collectively using both Lachman test and pivot shift test increases ability to distinguish between partial tears and complete ruptures. When comparing partial PL tears and complete ruptures the pivot shift test is more important than the Lachman test. In diagnosing a complete rupture, the evaluation of the endpoint during the Lachman test is more sensitive than the evaluation of the anterior tibial translation during the Lachman test.

CONCLUSION

Based on the findings of this study, a diagnostic algorithm has been implemented and is presented in this manuscript.

Anterior cruciate ligament reconstruction with remnant preservation: current concepts

Anterior cruciate ligament (ACL) tears are a common knee injury, and anatomic ACL reconstruction (ACLR) is now the standard of care to restore knee stability. Nevertheless, re-tear rates exceeding 5% are commonly reported, with an even higher percentage of patients unable to achieve preinjury knee function. As the torn ACL remnant contains elements (eg, cells, blood vessels and mechanoreceptors) essential to ACL function, it has been hypothesised that ACLR with remnant preservation may improve graft remodelling, in turn more quickly and completely restoring ACL structure and function. In this Current Concepts review, we summarise the present understanding of ACLR with remnant preservation, which includes selective bundle reconstruction of partial (one-bundle) ACL tears and single- and double-bundle ACLR with minimal to partial debridement of the torn ACL stump. Reported benefits of remnant preservation include accelerated graft revascularisation and remodelling, improved proprioception, decreased bone tunnel enlargement, individualised anatomic bone tunnel placement, improved objective knee stability and early mechanical support (with selective bundle reconstruction) to healing tissues. However, clinical studies of ACLR with remnant preservation are heterogeneous in the description of remnant characteristics and surgical technique. Presently, there is insufficient evidence to support the superiority of ACLR with remnant preservation over the standard technique. Future studies should better describe the ACL tear pattern, remnant volume, remnant quality and surgical technique. Progress made in understanding and applying remnant preservation may inform, and be reciprocally guided by, ongoing research on ACL repair. The goal of research on ACLR with remnant preservation is not only to achieve anatomic structural restoration of the ACL but also to facilitate biologic healing and regeneration to ensure a more robust and functional graft.

Diagnostic Accuracy of Lever Sign Test in Acute, Chronic, and Postreconstructive ACL Injuries

Background

The aim of this study is to determine the diagnostic accuracy of lever sign test in acute, chronic, and postreconstructive ACL injuries.

Methods

In total, 78 patients (69 male, 9 female) were subjected to clinical instability tests including Lachman, anterior drawer, pivot shift, and lever sign when an injury of the ACL was suspected. All tests were performed bilaterally in all patients in acute, chronic period and patients who underwent surgery after the anaesthesia and after the reconstruction at the last follow-up by two senior orthopaedic surgeons. MRI was taken from all patients and MRI image was taken as the reference test when evaluating the accuracy of the tests.

Results

The mean age of patients was 26.2±6.4 years (range, 17-44 years). Sensitivity and accuracy values of the Lachman, anterior drawer, pivot shift, and lever tests in the acute phase were calculated as 80.6%, 77.4%, 51.6%, 91.9% and 76.9%, 75.6%, 60.3%, 92.3%, respectively, and in the chronic (preanaesthesia) phase were calculated as 83.9%, 79.0%, 56.5%, 91.9% and 80.8%, 78.2%, 64.1%, 92.3%, respectively. Lachman, anterior drawer, pivot shift, and lever sign Acute's significant [AUC: 0.716, 0.731, 0.727, 0.928, respectively] activity were observed in the prediction of ACL rupture in MRI.

Conclusion

An ideal test to diagnose the integrity of the ACL should be easy to perform and reproducible with high sensitivity and specificity. From this perspective, the lever test seems to be a good test for clinicians in acute, chronic and postreconstructive ACL injuries.

The biological respect of the posterolateral bundle in ACL partial injuries. Retrospective analysis of 2 different surgical management of ACL partial tear in a population of high-demanding sport patients

INTRODUCTION

Most of the techniques described in the literature for the repair of chronic partial ACL tears do not spare the intact portion of the ligament. Aim of this study was to perform a retrospective analysis of the results obtained from the same ACL reconstructive surgical technique applicated by sparing or not AM bundle in a population of 42 sports patients.

MATERIALS AND METHODS

From 2010 to 2012, 42 patients who suffered ACL partial tear injury with rupture of posterolateral bundle were randomly divided in two groups homogenous for sex, age and sport-level activities. The first group with 22 patients performed ACL reconstruction with ST-GR over-the-top technique sacrificing the anteromedial (Removing AMT Group) remaining bundle intact; otherwise, the second group with 20 patients performed the same ACL reconstruction using only ST and maintaining AM bundle (Sparing AMT Group). All the patients were followed up by MRI evaluation at 12 months and clinical evaluation with IKDC score, Tegner score at 6, 12, 24, 36, 48 and 60 months. KT-1000 instrument was performed at 12 months. The results were analyzed statistically to evaluate differences between the two groups in terms of subjective outcome, and stability and for all the tests P < 0.05 was considered significant.

RESULTS

We did not observe any failure at final follow-up. IKDC subjective score at final follow-up in Removing AMT Group was 91.2 ± 2.3 in Sparing AMT Group was 92.4 ± 2.7. Tegner score at final follow-up was 7.2 ± 2.1 for Removing AMT Group and 7.8 ± 1.8 for Sparing AMT Group. Arthrometric evaluation performed with KT-1000 at final follow-up showed a side-to-side difference of 0.9 ± 1.3 mm in the Removing AMT Group against 0.8 ± 1.0 mm in the Sparing AMT Group. Return time to the sport was 7.1 months for Removing AMT Group otherwise 6.1 months for the Sparing AMT Group.

CONCLUSIONS

Both the described techniques in this study demonstrated to be able to guarantee a successful outcome. However, although no statistically significant differences were evident in terms of subjective and objective outcome between these techniques some evident benefits were evident using the sparing bundle technique in Sparing AMT Group such as better clinical scores at the final follow-up and an earlier return to sport activity.

Femoral entheseal shape and attachment angle as potential risk factors for anterior cruciate ligament injury

Although non-contact human ACL tears are a common knee injury, little is known about why they usually fail near the femoral enthesis. Recent histological studies have identified a range of characteristic femoral enthesis tidemark profiles and ligament attachment angles. We tested the effect of the tidemark profile and attachment angle on the distribution of strain across the enthesis, under a ligament stretch of 1.1. We employed a 2D analytical model followed by 3D finite element models using three constitutive forms and solved with ABAQUS/Standard. The results show that the maximum equivalent strain was located in the most distal region of the ACL femoral enthesis. It is noteworthy that this strain was markedly increased by a concave (with respect to bone) entheseal profile in that region as well as by a smaller attachment angle, both of which are features more commonly found in females. Although the magnitude of the maximum equivalent strain predicted was not consistent among the constitutive models used, it did not affect the relationship observed between entheseal shape and maximum equivalent strain. We conclude that a concave tidemark profile and acute attachment angle at the femoral ACL enthesis increase the risk for ACL failure, and that failure is most likely to begin in the most distal region of that enthesis.

Primary Anterior Cruciate Ligament Repair With Augmentation

Anterior cruciate ligament (ACL) tears are usually managed by reconstruction with autograft or allograft, but primary repair in carefully selected patients is a reasonable option. Proximal avulsions presenting early with excellent tissue quality are amenable to repair and healing. Restoration of native ACL preserves its proprioceptive and kinematic functions. A repair is less invasive and avoids graft-related problems, and faster rehabilitation is possible. Protection for the repair in the early stages will allow better healing. We present our technique of ACL repair using knotless suture anchors with high-strength sutures and protection using high-strength sutures tapes inserted through the same anchors.

Accuracy of the Lever Sign Test in the Diagnosis of Anterior Cruciate Ligament Injuries

Background:

The lever sign test is a new physical examination tool to diagnose anterior cruciate ligament (ACL) tears. Preliminary results suggest almost 100% sensitivity and specificity to diagnose acute and chronic complete ACL tears and clinically significant partial tears as compared with magnetic resonance imaging (MRI).

Purpose:

To assess the sensitivity and specificity of the lever sign test for the diagnosis of acute ACL injuries, as compared to MRI. We also aimed to determine the accuracy of the lever sign test compared with 3 other tests (anterior drawer, Lachman, and pivot shift) when performed by providers of various training levels, and with the patient awake or under anesthesia.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

We evaluated patients with a chief concern of acute (≤4 weeks) knee pain seen between October 2014 and January 2015, with a thorough history, physical examination, and standard radiographs. MRI was the reference standard; patients without an MRI evaluation were excluded. The 4 physical examination maneuvers were performed on each symptomatic knee during the initial clinic visit (for nonsurgical patients) or under anesthesia in the operating room (for surgical patients) by a randomly assigned undergraduate student, medical student, orthopaedic resident, or orthopaedic fellow. The senior author trained all staff to perform the lever sign test. Statistical analyses were performed.

Results:

Of 102 patients, 54 were surgical (28 female, 26 male), and 48 were nonsurgical (16 female, 32 male); the mean patient age was 23 years (range, 15-66 years). The overall accuracy of the lever sign test was 77% (63% sensitivity, 90% specificity); the accuracy was similar between patients under anesthesia and awake (77% vs 76%, respectively). There were no significant differences when comparing the sensitivity and specificity of the lever sign test with patients under anesthesia and awake (sensitivity: under anesthesia, 86%, and awake, 68% [P = .40]; specificity: under anesthesia, 85%, and awake, 96% [P = .17]). Furthermore, the accuracy of the lever sign test was similar when performed on female versus male patients (75% vs 79%, respectively) or when performed by undergraduate students and medical students compared with orthopaedic residents and fellows (84% vs 88%, respectively).

Conclusion:

Our study results challenge the exceptional sensitivity and specificity values (both 100%) of the lever sign test, as reported by the original author of the test.

The evolution of primary double-bundle ACL reconstruction and recovery of early post-operative range of motion

PURPOSE

The aim of this study was to analyse early post-operative range of motion (ROM) as our anatomic double-bundle (DB) anterior cruciate (ACL) reconstruction technique with respect to tunnel placement evolved. It is the hypothesis of this study that more anatomic placement of the femoral insertion site of the anteromedial (AM) bundle of the ACL results in better restoration of early post-operative knee range of motion.

METHODS

Two methods of DB ACL reconstruction regarding more accurate placement of the femoral AM tunnel in relation to its anatomic origin were compared. Patients presenting for 1- and 3-month post-operative clinical visits were examined for passive extension and active flexion by members of the clinical staff. Only patients undergoing primary DB reconstruction with allograft were included in the analyses. To determine the effects of the modified AM bundle placement on recovery of post-operative ROM, patients undergoing surgery in the 6 months before July 2006 (Group A, n = 50) were compared to patients undergoing surgery in the 6 months after July 2006 (Group B, n = 49).

RESULTS

A total of 99 patients met the inclusion criteria. More accurate placement of the AM bundle of the ACL was associated with a smaller side-to-side difference in flexion at 1 month (n.s.) and at 3 months (3° reduction, p < 0.03) after surgery. There was no effect on extension (n.s.) CONCLUSION: More anatomic placement of the femoral insertion of the AM bundle was associated with improved knee flexion. The study translates the findings of previous anatomic basic science research to demonstrate improved restoration of normal joint motion. This ideally leads to improved long-term clinical outcomes and maintenance of joint and cartilage health.

LEVEL OF EVIDENCE

III.

Clinical outcomes and biomechanical analysis of posterolateral bundle augmentation in patients with partial anterior cruciate ligament tears

PURPOSE

To examine the clinical and biomechanical results of posterolateral (PL) augmentation to reconstruct damaged PL bundle while preserving the less-damaged anteromedial bundle for partial anterior cruciate ligament (ACL) tears in comparison with double-bundle ACL reconstruction.

METHODS

Sixteen patients who underwent PL augmentation for partial ACL tears (Group P) and 37 patients who underwent double-bundle ACL reconstructions for complete ACL tears were examined (Group D). Anterior tibial translation (ATT) was evaluated using the KT-1000 arthrometer. ATT during the Lachman test and acceleration of posterior tibial translation (APT) during the pivot shift test were evaluated using an electromagnetic measurement system (EMS). Clinical outcomes were evaluated using the Lysholm score. Second-look arthroscopy was performed 1 year after surgery.

RESULTS

The mean postoperative Lysholm scores were 91.7 ± 12.2 and 94.6 ± 7.2 in Groups P and D, respectively, and there was no statistically significant difference between the two groups. The mean side-to-side difference of ATT on the KT-1000 was significantly improved in both Groups P and D. In the EMS analysis, the mean side-to-side difference of ATT and the mean APT were significantly improved in both Groups P and D. There was no significant difference in the second-look evaluation between the two groups.

CONCLUSIONS

The clinical and biomechanical outcomes of PL augmentation were satisfactorily comparable to those of double-bundle ACL reconstruction. PL augmentation could be a useful treatment option for patients with partial ACL tears.

LEVEL OF EVIDENCE

IV.

Biologic Approaches for the Treatment of Partial Tears of the Anterior Cruciate Ligament: A Current Concepts Review

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) has been established as the gold standard for treatment of complete ruptures of the anterior cruciate ligament (ACL) in active, symptomatic individuals. In contrast, treatment of partial tears of the ACL remains controversial. Biologically augmented ACL-repair techniques are expanding in an attempt to regenerate and improve healing and outcomes of both the native ACL and the reconstructed graft tissue.

PURPOSE

To review the biologic treatment options for partial tears of the ACL.

STUDY DESIGN

Review.

METHODS

A literature review was performed that included searches of PubMed, Medline, and Cochrane databases using the following keywords: partial tear of the ACL, ACL repair, bone marrow concentrate, growth factors/healing enhancement, platelet-rich plasma (PRP), stem cell therapy.

RESULTS

The use of novel biologic ACL repair techniques, including growth factors, PRP, stem cells, and bioscaffolds, have been reported to result in promising preclinical and short-term clinical outcomes.

CONCLUSION

The potential benefits of these biological augmentation approaches for partial ACL tears are improved healing, better proprioception, and a faster return to sport and activities of daily living when compared with standard reconstruction procedures. However, long-term studies with larger cohorts of patients and with technique validation are necessary to assess the real effect of these approaches.

Comparison of clinical, MRI and arthroscopic assessments of chronic ACL injuries, meniscal tears and cartilage defects

PURPOSE

The aim of this study was to compare the accuracy of clinical examination to that of MRI evaluated by two independent radiologists for the diagnosis of meniscal tears and chronic anterior cruciate ligament injuries and to assess the MRI accuracy in the diagnosis of cartilage defects.

METHODS

Seventy-six consecutive patients with suspected intra-articular knee pathology were prospectively evaluated by objective examination, 1.5 T MRI, re-examined by trained radiologist and arthroscopy. Accuracy, sensitivity, specificity, positive predictive value and negative predictive value were calculated. Agreement analysis with kappa (К) coefficient values was performed for meniscal and ACL tears.

RESULTS

No differences were found between diagnostic accuracy of clinical examination, the first and second MRI reports in diagnosis of medial meniscus (84 vs 96 vs 97 %) and anterior cruciate ligament injuries (93 vs 78 vs 89 %). For the lateral meniscal tears, the accuracy of the second radiologist was significantly higher than those of the first (96 vs 75 %; p < 0.01) and clinical examination (96 vs 86 %; p = 0.02). High diagnostic values were obtained for the diagnosis of full-thickness chondral defects with sensitivity of 100 %, specificity of 95 % and accuracy of 95 %.

CONCLUSION

Clinical and MRI evaluations have no differences in the diagnosis of medial meniscus and anterior cruciate ligament injuries. A trained radiologist obtained better sensitivity, specificity and accuracy in the diagnosis of lateral meniscus. 1.5 T MRI does not represent the technique of choice in the evaluation of chondral defect but demonstrated high diagnostic accuracy for detection of full-thickness chondral defects.

LEVEL OF EVIDENCE

Diagnostic prospective study, Level II.

Acute Proximal Anterior Cruciate Ligament Tears: Outcomes After Arthroscopic Suture Anchor Repair Versus Anatomic Single-Bundle Reconstruction

PURPOSE

To compare clinical and radiologic results of primary anterior cruciate ligament (ACL) suture anchor repair and microfracturing with anatomic ACL single-bundle reconstruction in patients with acute proximal ACL avulsion tears.

METHODS

Between January 2010 and December 2013, 420 patients underwent ACL treatment. Forty-one patients were included in this study. The inclusion criteria were as follows: unilateral acute proximal ACL rupture, concomitant meniscus lesions, no previous knee ligament surgery, and no additional ligament injuries or absence of ligament injury of the contralateral knee. Preoperative magnetic resonance imaging confirming a proximal avulsion tear of the ACL was required. Patients had to undergo surgical treatment within 6 weeks after injury. Follow-up examination included Lachman and pivot-shift testing, KT-1000 measurement, and the International Knee Documentation Committee score.

RESULTS

At a mean follow-up of 28 months (range, 24 to 31 month), 20 patients in each group were available. A mean KT-1000 arthrometer result of less than 3 mm indicated stability in all patients (P = .269). Three patients had a 1+ Lachman test (P = .072) and 4 patients had a 1+ pivot-shift test in the ACL repair group (P = .342). The International Knee Documentation Committee score results did not differ significantly (P > .99), but there was a significant correlation between poor results and failure rate (P = .001) in the refixation group. The failure rate was 15% in the ACL refixation group and 0% in the reconstruction group (P = .231). Magnetic resonance imaging confirmed homogeneous signal and proper ACL position in 100% of patients in the control group and 86% in the ACL repair group.

CONCLUSIONS

Proximal refixation of the ACL using knotless suture anchors and microfracturing restores knee stability and results in comparable functional outcomes to a control group treated with single-bundle ACL reconstruction. The results suggest that refixation of the ACL is a feasible treatment option in selected patients.

LEVEL OF EVIDENCE

Level III, case-control study.

Behind-remnant arthroscopic observation and scoring of femoral attachment of injured anterior cruciate ligament

PURPOSE

To describe the femoral anterior cruciate ligament (ACL) attachment based on the behind-remnant observation with a new scoring system and to investigate the characteristics of an ACL injured knee.

METHODS

One hundred and twenty-six ACL injured knees with four standardized arthroscopic photos and full evaluation under anaesthesia were included in the study. Sixty non-ACL injured knees were also evaluated as control. A scoring system for the femoral ACL attachment was set as follows based on behind-remnant findings; the direct insertion was divided into three portions as proximal, middle and distal. The fibrous extension from the articular surface (indirect insertion) and the severity of synovitis were also graded into 2, 1 and 0 points. The total score was 10 as full marks. The correlation between each score and total score, as well as age at surgery, gender, anterior laxity, pivot-shift test and meniscus injuries, was statistically evaluated with a significance of 0.05.

RESULTS

The femoral attachment score of the ACL injured knees was statistically different from that of the non-ACL injured knees. Anterior laxity was dependent only on the integrity of the proximal portion. Knee instability was significantly correlated with the status of the direct insertion. Medial and lateral meniscus injuries were correlated with the middle part and the distal part of the direct insertion, respectively. The direct insertion was less preserved in distal and articular sides.

CONCLUSION

Arthroscopic observation behind the remnant of the injured ACL showed clearer findings of the femoral attachment than that from the front. Behind-remnant observation greatly assists in the creation of a correct anatomical tunnel with the preserving remnant. The scoring system indicated several significant correlations between the score and preoperative patient status.

A Comparison between Clinical Results of Selective Bundle and Double Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE

The purpose of this study was to compare the clinical outcomes of arthroscopic anatomical double bundle (DB) anterior cruciate ligament (ACL) reconstruction with either selective anteromedial (AM) or posterolateral (PL) bundle reconstruction while preserving a relatively healthy ACL bundle.

MATERIALS AND METHODS

The authors evaluated 98 patients with a mean follow-up of 30.8±4.0 months who had undergone DB or selective bundle ACL reconstructions. Of these, 34 cases underwent DB ACL reconstruction (group A), 34 underwent selective AM bundle reconstruction (group B), and 30 underwent selective PL bundle reconstructions (group C). These groups were compared with respect to Lysholm and International Knee Documentation Committee (IKDC) score, side-to-side differences of anterior laxity measured by KT-2000 arthrometer at 30 lbs, and stress radiography and Lachman and pivot shift test results. Pre- and post-operative data were objectively evaluated using a statistical approach.

RESULTS

The preoperative anterior instability measured by manual stress radiography at 90° of knee flexion in group A was significantly greater than that in groups B and C (all p<0.001). At last follow-up, mean side-to-side instrumented laxities measured by the KT-2000 and manual stress radiography were significantly improved from preoperative data in all groups (all p<0.001). There were no significant differences between the three groups in anterior instability measured by KT-2000 arthrometer, pivot shift, or functional scores.

CONCLUSION

Selective bundle reconstruction in partial ACL tears offers comparable clinical results to DB reconstruction in complete ACL tears.

On the heterogeneity of the femoral enthesis of the human ACL: microscopic anatomy and clinical implications

BACKGROUND

Most ruptures of the native anterior cruciate ligament (ACL) and ACL graft occur at, or near, the femoral enthesis, with the posterolateral fibers of the native ligament being especially vulnerable during pivot landings. Characterizing the anatomy of the ACL femoral enthesis may help us explain injury patterns which, in turn, could help guide injury prevention efforts. It may also lead to improved anatomic reconstruction techniques given that the goal of such techniques is to replicate the knee's normal anatomy. Hence, the aim of this study was to investigate the microscopic anatomy of the ACL femoral enthesis and determine whether regional differences exist.

METHODS

Fifteen human ACL femoral entheses were histochemically processed and sectioned along the longitudinal axis of the ACL at 20, 40, 60, and 80 % of the width of the enthesis. Four thick sections (100 μm) per enthesis were prepared, stained, and digitized. From these sections, regional variations in the quantity of calcified and uncalcified fibrocartilage, the angle at which the ligament originates from the bone, and the shape profile of the tidemark were quantified.

RESULTS

At least 33 % more calcified fibrocartilage and 143 % more uncalcified fibrocartilage were found in the antero-inferior region, which corresponds to the inferior margin of the origin of the anteromedial ACL fibers, than all other regions (Ps < 0.05). In addition, the anteromedial fibers of the ACL originated from the femur at an angle six times greater than did its posterolateral fibers (P = 0.032). Finally, average entheseal tidemark profiles correlated bilaterally (Pearson's r = 0.79; P = 0.036), the most common profile being convex with a single re-entrant.

CONCLUSIONS

Systematic regional differences were found in fibrocartilage quantity and collagen fiber attachment angles. The marked differences may reflect differences in the loading history of the various regions of the ACL femoral enthesis. These differences, which could affect the potential for injury, should also be considered when developing new ACL reconstruction approaches.

CT assessment of femoral tunnel placement after partial ACL reconstruction

INTRODUCTION

When one of the anterior cruciate ligament (ACL) bundles is torn, it seems appropriate to preserve the remaining bundle to improve the vascularization and proprioception of the graft, and to reproduce the attachment sites of the torn bundle. After ACL reconstruction, the functional result is worse when the tunnels are positioned further away from the native ACL's isometric attachment points. The goal of this study was to use CT 3D reconstructions to analyse the position of the femoral tunnel following partial ACL reconstruction and to compare it to complete ACL reconstruction cases. We hypothesized that the femoral tunnel positioning was optimal during partial ACL reconstruction.

METHODS

In this prospective single-centre study, 16 patients who underwent isolated anteromedial bundle reconstruction were evaluated during the immediate postoperative period using 3D reconstruction of CT images. During this same period, 180 patients who underwent complete ACL reconstruction in the same surgery unit served as a control group.

RESULTS

In the partial ACL reconstruction group, 6 tunnels (37.5%) were in the optimal position and 10 tunnels (62.5%) were not. In the complete ACL reconstruction group, 124 femoral (68.9%) were in the optimal position and 56 (31.1%) were not (P<0.05).

DISCUSSION

Femoral tunnel positioning is not always optimal in patients who undergo partial ACL reconstruction. Three-dimensional CT reconstruction is a good tool to help surgeons detect and learn from their errors.

LEVEL OF EVIDENCE

III (case-control study).

Partial tears of the anterior cruciate ligament

Partial anterior cruciate ligament (ACL) tears were first described nearly fifty years ago but the optimal treatment for these injuries continues to be a subject of considerable debate. A question remains whether it is advantageous to preserve the ACL remnant and augment it with a graft, or to debride it and proceed with a standard ACL reconstruction unhindered by remnant fibers in the notch. Clinical outcomes of bundle preserving surgery are promising. An increasingly large body of scientific evidence suggests that augmenting the intact bundle is beneficial in terms of vascularity, proprioception and kinematics. With this knowledge, a number of surgeons have developed techniques to augment the intact bundle of the ACL in partial tears and to biologically enhance standard reconstruction techniques by preserving the ACL remnant. Correct tunnel placement is critical for achieving successful short and long-term outcomes after ACL reconstruction. However, published studies have several limitations including a limited number of patients and lack of control groups for direct comparison of outcomes. Concerns continue to exist with respect to an increased risk of impingement following augmentation, responsible of cyclops syndrome. The objective of this article was to outline the diagnostic approach, describe a reproducible and simple surgical procedure that allows correct femoral tunnel placement without the need for aggressive notch debridement and report the clinical outcome of partial ACL reconstruction.

The arthroscopical and radiological corelation of lever sign test for the diagnosis of anterior cruciate ligament rupture

The aim of the current study was to evaluate the sensitivity of the lever sign test and the widely used basic tests of the Lachman, anterior drawer and pivot shift tests, both under anaesthesia and without anaesthesia, according to the gold standard diagnostic arthroscopic results in patients undergoing anterior cruciate ligament reconstruction. The study included 117 patients, diagnosed with ACL tear which was definitively determined during an arthroscopic surgical procedure applied. Before anaesthesia and while under anaesthesia, the Lachman, anterior drawer, pivot shift and lever sign tests were applied to all patients. Evaluation was made of MR images for each patient and documented. The patients comprised 96 males and 21 females, witha mean age of 25.8 ± 5.9 years (range, 17-45 years). Total tear was determined in 82 cases, anteromedial (AM) bundle in 14, posterolateral (PL) bundle in 13 and elongation in 8. Pre-anaesthesia positivity was found in lever sign at 94.2 %, Lachman at 80.5 %, pivot shift at 62.3 % and anterior drawer at 60.1 %. These rates were determined after anaesthesia as lever sign 98.4 %, Lachman 88.7 %, pivot shift 88.3 % and anterior drawer 84.2 %. The lever sign test can be easily applied clinically and it seems to have higher sensitivity than the Lachman test which is the basis of classic information, it should be included in routine clinical practice. In the light of the results of this study, further studies are required to review the accepted view that the Lachmann test is the most reliable test.

Quantitative comparison of the microscopic anatomy of the human ACL femoral and tibial entheses

The femoral enthesis of the human anterior cruciate ligament (ACL) is known to be more susceptible to injury than the tibial enthesis. To determine whether anatomic differences might help explain this difference, we quantified the microscopic appearance of both entheses in 15 unembalmed knee specimens using light microscopy, toluidine blue stain and image analysis. The amount of calcified fibrocartilage and uncalcified fibrocartilage, and the ligament entheseal attachment angle were then compared between the femoral and tibial entheses via linear mixed-effects models. The results showed marked differences in anatomy between the two entheses. The femoral enthesis exhibited a 3.9-fold more acute ligament attachment angle than the tibial enthesis (p<0.001), a 43% greater calcified fibrocartilage tissue area (p<0.001), and a 226% greater uncalcified fibrocartilage depth (p<0.001), with the latter differences being particularly pronounced in the central region. We conclude that the ACL femoral enthesis has more fibrocartilage and a more acute ligament attachment angle than the tibial enthesis, which provides insight into why it is more vulnerable to failure.

Direct Visualization of Existing Footprint and Outside-In Drilling of the Femoral Tunnel in Anterior Cruciate Ligament Reconstruction in the Knee

Improper femoral tunnel placement in anterior cruciate ligament (ACL) reconstruction is a significant problem and may be a cause of ACL graft failure and abnormal kinematics, which may lead to late degenerative changes after reconstruction. Recently, there has been concern that the transtibial approach may contribute to nonanatomic placement of the femoral tunnel, resulting in abnormal knee kinematics. Tibial-independent techniques can provide more anatomic placement of the ACL graft, but these can be technically demanding. This technical note describes the senior author's technique to directly identify the femoral ACL remnant and use the center of the femoral ACL footprint and retrograde drilling to create an anatomic femoral socket for single-bundle reconstruction. This technique provides femoral tunnel placement based on identification of a patient-specific ACL footprint instead of averaged anatomic measurements from large groups. This technique has been shown to produce anatomic ACL graft position and orientation and restore more normal knee kinematics.

Sonographically Guided Anterior Cruciate Ligament Injection: Technique and Validation

OBJECTIVE

To describe and validate a practical technique for sonographically guided anterior cruciate ligament (ACL) injections.

DESIGN

Prospective, cadaveric laboratory investigation.

SETTING

Procedural skills laboratory in a tertiary medical center.

SUBJECTS

Ten unembalmed, cadaveric mid-thigh-knee-ankle foot specimens (5 left knees and 5 right knees; 5 male and 5 female) from 10 donors aged 76 to 93 years (mean 85.6 years) with body mass indices of 17.6 to 42.2 kg/m(2) (mean 28.8 kg/m(2)).

METHODS

A single, experienced operator used a 22-gauge, 63.5-mm stainless steel needle and a 12-3-MHz linear transducer to inject 1.5 mL of diluted colored latex into the ACLs of 10 unembalmed cadaveric specimens via an in-plane, caudad-to-cephalad approach, long axis to the ACL. At a minimum of 24 hours postinjection, specimens were dissected, and the presence and distribution of latex within the ACL assessed by a study co-investigator.

MAIN OUTCOME

Presence and distribution of latex within the ACL.

RESULTS

All 10 injections accurately delivered latex into the proximal (femoral), midsubstance, and distal (tibial) portions of the ACL. No specimens exhibited evidence of needle injury or latex infiltration with respect to the menisci, hyaline cartilage, or posterior cruciate ligament.

CONCLUSIONS

Sonographically guided intra-ligamentous ACL injections are technically feasible and can be performed with a high degree of accuracy. Sonographically guided ACL injections could be considered for research and clinical purposes to directly deliver injectable agents into the healing ACL postinjury or postreconstruction.

Partial tears of anterior cruciate ligament: Results of single bundle augmentation

BACKGROUND

Partial tears of the anterior cruciate ligament (ACL) are common and usually present with symptomatic instability. The remnant fibers are usually removed and a traditional ACL reconstruction is done. But with increased understanding of ACL double bundle anatomy, the remnant tissue preservation along with a single bundle augmentation of the torn bundle is also suggested. The purpose of this study was to evaluate the results of selective anatomic augmentation of symptomatic partial ACL tears. Our hypothesis is that this selective augmentation of partial ACL tears could restore knee stability and function.

MATERIALS AND METHODS

Consecutive cases of 314 ACL reconstructions, 40 patients had intact ACL fibers in the location corresponding to the anteromedial (AM) or posterolateral (PL) bundle and were diagnosed as partial ACL tears perioperatively. All patients underwent selective augmentation of the torn bundle, while keeping the remaining fibers intact using autogenous hamstring graft. A total of 38 patients (28 males, 10 females) were available with a minimum of 3 years followup. 26 cases had AM bundle tears and 12 cases had PL bundle tears respectively. Patients were assessed with International Knee Documentation Committee (IKDC) 2000 Knee Evaluation Form, Lysholm score; instrumented knee testing was performed with the arthrometer (KT 2000). Statistical analysis was performed to compare the preoperative and postoperative objective evaluation.

RESULTS

At 3 years followup, 31.6% patients were graded A, 65.8% were graded B and 2.6% was graded C at IKDC objective evaluation. Manual laxity tests, Lysholm's score, mean side to side instrumental laxity and Tegner activity score improved significantly. 76% patients returned to preinjury level of sports activity after augmentation.

CONCLUSION

The results of anatomic single bundle augmentation in partial ACL tears are encouraging with excellent improvement in functional scores, side to side laxity and return to sports activity.

Associations between isolated bundle tear of anterior cruciate ligament, time from injury to surgery, and clinical tests

PURPOSE

To evaluate the associations between isolated anteromedial (AM) or posterolateral (PL) bundle tear of the anterior cruciate ligament (ACL), the time from injury to surgery, and various clinical tests.

METHODS

36 women and 189 men aged 16 to 52 (mean, 26.4) years underwent ACL reconstruction of the right (n=107) and left (n=118) knees. Patients were evaluated for the International Knee Documentation Committee Subjective Knee Score, Cincinnati Knee Rating System Score, anterior drawer test, Lachman test, pivot shift test, KT1000 arthrometer measurement, isokinetic muscle tests of the extensors, and functional tests (single leg hop and timed hop test). Examination under anaesthesia (EUA) was also performed, followed by diagnostic arthroscopy. The integrity of the ACL bundles was tested using a probe. The AM and PL bundles were morphologically intact if structurally present, and functionally intact if not lax on probing.

RESULTS

Of the 225 patients, 8 had isolated AM bundle tears, 2 had isolated PL bundle tears, and 215 had complete ACL tears in terms of function. The corresponding numbers were 30, 13, and 182 in terms of morphology. Compared with patients with complete ACL tear, the mean time from injury to surgery was significantly shorter in patients with isolated AM or PL bundle tear in terms of function (17.5 vs. 5.6 months, p<0.001) and morphology (17.5 vs. 8.8 months, p<0.001). Compared with patients with complete ACL tear, those with a functionally intact PL bundle had a higher rate of negative pivot shift test in preoperative evaluation (1% vs. 17%, p=0.002) and EUA (1% vs. 63%, p<0.001), and had a higher rate of negative Lachman test in EUA (1% vs. 25%, p=0.02).

CONCLUSION

The time from injury to surgery was shorter in patients with isolated bundle ACL tear. In patients with ACL deficiency, the pivot shift test was useful in detecting an intact PL bundle.

Anatomic anterior cruciate ligament (ACL) reconstruction: a global perspective. Part 1

PURPOSE

In August 2011, orthopaedic surgeons from more than 20 countries attended a summit on anatomic anterior cruciate ligament (ACL) reconstruction. The summit offered a unique opportunity to discuss current concepts, approaches, and techniques in the field of ACL reconstruction among leading surgeons in the field.

METHODS

Five panels (with 36 panellists) were conducted on key issues in ACL surgery: anatomic ACL reconstruction, rehabilitation and return to activity following anatomic ACL reconstruction, failure after ACL reconstruction, revision anatomic ACL reconstruction, and partial ACL injuries and ACL augmentation. Panellists' responses were secondarily collected using an online survey.

RESULTS

Thirty-six panellists (35 surgeons and 1 physical therapist) sat on at least one panel. Of the 35 surgeons surveyed, 22 reported performing "anatomic" ACL reconstructions. The preferred graft choice was hamstring tendon autograft (53.1 %) followed by bone-patellar tendon-bone autograft (22.8 %), allograft (13.5 %), and quadriceps tendon autograft (10.6 %). Patients generally returned to play after an average of 6 months, with return to full competition after an average of 8 months. ACL reconstruction "failure" was defined by 12 surgeons as instability and pathological laxity on examination, a need for revision, and/or evidence of tear on magnetic resonance imaging. The average percentage of patients meeting the criteria for "failure" was 8.2 %.

CONCLUSIONS

These data summarize the results of five panels on anatomic ACL reconstruction. The most popular graft choice among surgeons for primary ACL reconstructions is hamstring tendon autograft, with allograft being used most frequently employed in revision cases. Nearly half of the surgeons surveyed performed both single- and double-bundle ACL reconstructions depending on certain criteria. Regardless of the technique regularly employed, there was unanimous support among surgeons for the use of "anatomic" reconstructions using bony and soft tissue remnant landmarks.

The concept of individualized anatomic anterior cruciate ligament (ACL) reconstruction

PURPOSE

To describe the concept of individualized anatomic anterior cruciate ligament (ACL) reconstruction.

METHODS

The PubMed/Medline database was searched using keywords pertaining to ACL reconstruction. Relevant articles were reviewed in order to summarize important concepts of individualized surgery in ACL reconstruction. Surgical experiences with case examples are also highlighted.

RESULTS

Individualized ACL surgery allows for the customization of surgery to each individual patient. Accounting for graft selection and other characteristics such as anatomy, lifestyle and activity preferences may provide the patient with the best potential for a successful outcome. The surgeon should be comfortable with a variety of graft harvests and surgical techniques when practicing individualized surgery.

CONCLUSION

Individualized anatomic ACL reconstruction is founded on the objective evaluation of functional anatomy and individual characteristics, thereby restoring the ACL as closely as possible to the native anatomy and function. The adoption and subsequent use of individualized surgery may facilitate improved clinical as well as objective outcomes, particularly in the long term.

LEVEL OF EVIDENCE

V.

Biomechanical analysis of knee laxity with isolated anteromedial or posterolateral bundle-deficient anterior cruciate ligament

PURPOSE

The purpose of this study was to clarify the changes in the kinematics of the knee that result from isolated deficiency of the anteromedial (AM) or posterolateral (PL) bundle.

METHODS

Fourteen cadaveric knees were mounted in a 6-df rig and tested using the following 5 loading conditions: 90-N anterior and posterior tibial loads, 5-Nm internal and external tibial torques, and a simulated pivot-shift test. Tibiofemoral kinematics during flexion-extension was recorded with an optical tracking system for (1) intact knees, (2) knees in which the isolated AM bundle was cut, (3) knees in which the isolated PL bundle was cut, and (4) anterior cruciate ligament (ACL)-deficient knees. The distances between the femoral and tibial attachments of the AM and PL bundles of the ACL were also calculated.

RESULTS

Anterior translation laxity under an anterior tibial load, rotational laxity under an internal tibial torque, and anterior translation laxity under pivot-shift loading were significantly different between the knees with AM and PL bundle deficiencies (P < .024), but the changes were small: less than 3 mm or 1.5°. The AM bundle distance increased significantly more after an AM bundle tear (P = .004) than after a PL bundle tear in flexion. Cutting the PL bundle did not have a significant effect on the lengths between the bundle attachments.

CONCLUSIONS

An isolated AM or PL bundle tear caused a small increase in laxity (<3 mm or <1.5°).

CLINICAL RELEVANCE

If there is a clinically identifiable increase in laxity, then--in addition to the isolated tear of the AM or PL bundle--there must also be a tear of the other bundle of the ACL, or at least a partial tear.

[Reconstruction of partial anterior cruciate ligament tears]

OBJECTIVE

Partial augmentation of isolated tears of the anteromedial and posterolateral bundle of the anterior cruciate ligament (ACL) with autologous hamstring tendons. The intact fibers of the ACL are preserved.

INDICATIONS

Symptomatic isolated tear of the anteromedial or posteromedial bundle of the ACL or rotational instability after ACL reconstruction with malplaced tunnels (e.g., high femoral position)

CONTRAINDICATIONS

In revision cases: loss of motion due to malplaced ACL and excessive tunnel widening of the present tunnels with the risk of tunnel confluence.

SURGICAL TECHNIQUE

Examination of anterior-posterior translation and rotational instability under anesthesia. Diagnostic arthroscopy, repetition of the clinical examination under direct visualization of the ACL, meticulous probing of the functional bundles. Resection of ligament remnants, preparation/preservation of the femoral and tibial footprint. Harvesting one of the hamstring tendons, graft preparation. Positioning of a 2.4 mm K-wire in the anatomic center of the femoral anteromedial/posterolateral bundle insertion, cannulated drilling according to the graft diameter. Positioning of a 2.4 mm K-wire balanced according to the femoral tunnel at the tibia, cannulated drilling. Insertion of the graft and fixation.

POSTOPERATIVE MANAGEMENT

Analogous to that for ACL reconstruction.

How useful is MRI in diagnosing isolated bundle ACL injuries?

BACKGROUND

Selective bundle anterior cruciate ligament (ACL) reconstruction and/or remnant ACL preservation may be reasonable options for some patients. However, the frequency of isolated anteromedial (AM) or posterolateral (PL) bundle injuries in patients undergoing ACL reconstruction is unknown, and the value of MRI for prediction of this injury pattern is likewise unknown.

QUESTIONS/PURPOSES

We sought to determine (1) the proportion of knees with an intact AM or PL bundle in patients undergoing ACL reconstruction; (2) whether MRI predicted the bundle conditions seen at the time of surgery; and (3) whether the accuracy of the MRI prediction was affected by the timing of MRI after injury.

METHODS

During primary ACL reconstructions of 156 knees, conditions of AM and PL bundles were separately examined and classified into three categories: (1) completely torn; (2) attenuated; and (3) intact. Then, the bundles were assessed by blinded observers on MRI and classified into the corresponding three categories for 77 patients who had an MRI at our institution using a standard protocol. Diagnostic accuracy of MRI was computed, and the early MRI group (≤6 weeks from injury to MRI acquisition) was compared with the late MRI group (>6 weeks).

RESULTS

Only 11 (7%) of the 156 knees we treated had an intact AM (one knee) or PL bundle (10 knees). Another 55 knees (35%) had a structurally continuous but attenuated AM or PL bundle. The overall diagnostic accuracy of MRI was 83%; accuracy was better for the AM bundle than the PL bundle (91% versus 78%; p=0.026). MR prediction was less accurate in the early MRI group, particularly for PL bundle injury.

CONCLUSIONS

An isolated bundle tear is uncommon in patients with ACL tears undergoing reconstruction. MRI can help surgeons predict bundle injury pattern with satisfactory precision, but caution should be used in predicting PL bundle injury using MRI with early acquisition time from injury.

LEVEL OF EVIDENCE

Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Posterolateral Bundle Reconstruction With Anteromedial Bundle Remnant Preservation in ACL Tears: Clinical and MRI Evaluation of 39 Patients With 24-Month Follow-up

Background:

Augmentation consisting of a selective reconstruction of the ruptured bundle while preserving the remnant bundle has been proposed as a treatment option for partial anterior cruciate ligament (ACL) tears. Good clinical outcomes after selective anteromedial (AM) bundle augmentation have been reported, whereas little is known about selective reconstruction of the posterolateral (PL) bundle with preservation of the AM bundle remnant.

Purpose:

The purpose of this study was to evaluate the clinical outcomes and the magnetic resonance imaging (MRI) characteristics of selective PL bundle reconstruction with a median follow-up of 24 months.

Study Design:

Case series; Level of evidence, 4.

Methods:

In a consecutive series of 741 ACL reconstructions, 44 patients underwent a selective PL bundle reconstruction with preservation of the AM remnant. Four patients with contralateral knee ligament surgery and 1 patient who sustained a traumatic rupture of his graft were excluded, leaving 39 patients for final evaluation. Clinical evaluation of knee function and laxity were recorded preoperatively and at a mean 24.2-month follow-up. Magnetic resonance imaging was performed on 35 patients at a mean 25.9-month follow-up for evaluation of graft and remnant bundle continuity, tunnel enlargement, and graft remodeling status by measuring the signal intensity of the graft (contrast/noise quotient [CNQ]).

Results:

Tegner and Lysholm knee scores were significantly improved after surgery. The subjective International Knee Documentation Committee (IKDC) score was 43.5 ± 16.6 preoperatively and 89.9 ± 6.6 at the final follow-up (P < .01). The objective IKDC score was “B” for 17 patients, “C” for 21 patients, and “D” for 1 patient preoperatively, while it was “A” for 34 patients and “B” for 5 patients postoperatively (P < .01). The mean side-to-side anteroposterior laxity was 5 mm (range, 4-10 mm) preoperatively and 1.5 mm (range, −1 to 4 mm) at final follow-up (P < .01). On MRI, the graft was visible and continuous in all cases. No cyclops lesions were noted. The average CNQ for the PL graft and the AM remnant bundle was 3.2 ± 1 and 2.9 ± 1.2, respectively. Minimum bone tunnel enlargement was found.

Conclusion:

Selective PL bundle reconstruction restores knee stability and function. At final follow-up, MRI showed continuity of the PL graft without signs of dramatic tunnel enlargement or cyclops syndrome.

Methods to diagnose acute anterior cruciate ligament rupture: a meta-analysis of physical examinations with and without anaesthesia

PURPOSE

The aims of this meta-analysis were to determine the sensitivity and specificity of the Lachman, pivot shift and anterior drawer test for acute complete ACL rupture in the office setting and under anaesthesia. It was hypothesized that the Lachman test is the most sensitive and the pivot shift test the most specific. Secondly, it was hypothesized that the sensitivity and specificity of all three exams increases when the examination is performed under anaesthesia.

METHODS

An electronic database search was performed using MEDLINE and EMBASE. All cross-sectional and cohort studies comparing one or more physical examination tests for diagnosing acute complete ACL rupture to an accepted reference standard such as arthroscopy, arthrotomy and MRI were included.

RESULTS

Twenty studies were identified and included. The overall sensitivity of the Lachman test was 0.81 and the specificity 0.81; with anaesthesia, the sensitivity was 0.91 and the specificity 0.78. For the anterior drawer test, the sensitivity was 0.38 and the specificity 0.81; with anaesthesia, the sensitivity was 0.63 and the specificity 0.91. The sensitivity of the pivot shift test was 0.28 and the specificity 0.81; with anaesthesia, the sensitivity was 0.73 and the specificity 0.98.

CONCLUSION

In the office setting, the Lachman test has the highest sensitivity for diagnosing an acute, complete ACL rupture, while all three tests had comparable specificity. When the examination was performed under anaesthesia, the Lachman test still obtained the highest sensitivity, but the pivot shift test was the most specific.

LEVEL OF EVIDENCE

Meta-analysis of diagnostic test accuracy, Level II.

Clinical relevance and imaging features of isolated single bundle anterior cruciate tear and single bundle augmentation

The anterior cruciate ligament (ACL) consists of two anatomic and functional bundles, the anteromedial and posterolateral bundle. Depending on the mechanism of injury, there are different injury patterns, demonstrating a wide spectrum of partial ACL tears. Single bundle partial ACL tears can be treated with augmentation. Theoretically, sparing the intact parts of the ACL may increase vascularization and proprioception and may result in better stability and improved clinical outcome for the patient. In this article, we review the anatomy and function of ACL bundles and demonstrate cases of single bundle ACL tear with subsequent augmentation.

Changes in dynamic medial tibiofemoral contact mechanics and kinematics after injury of the anterior cruciate ligament: a cadaveric model

The effects of tears of the anterior cruciate ligament on knee kinematics and contact mechanics during dynamic everyday activities, such as gait, remains unclear. The objective of this study was to characterize anterior cruciate ligament-deficient knee contact mechanics and kinematics during simulated gait. Nine human cadaveric knees were each augmented with a sensor capable of measuring dynamic normal contact stresses on the tibial plateau, mounted on a load-controlled simulator, and subjected to physiological, multidirectional, dynamic loads to mimic gait. Using a mixed model with random knee identifiers, confidence intervals were constructed for contact stress before and after anterior cruciate ligament transection at two points in the gait cycle at which axial force peaked (14% and 45% of the gait cycle). Kinematic and contact mechanics changes after anterior cruciate ligament transection were highly variable across knees. Nonetheless, a statistically significant increase in contact stress in the posterior-central aspect of the medial tibial plateau at 45% of the gait cycle was identified, the location of which corresponds to the location of degenerative changes that are frequently found in patients with chronic anterior cruciate ligament injury. The variability in the contact stress in other regions of the medial plateau at 45% of the gait cycle was partly explained by the variations in osseous geometry across the nine knees tested. At 14% of gait, there was no significant change in peak contact stress after anterior cruciate ligament transection in any of the four quadrants, and none of the possible explanatory variables showed statistical significance. Understanding the variable effect of anterior cruciate ligament injury on contact mechanics based on geometric differences in osseous anatomy is of paramount clinical importance and may be invaluable to select the best reconstruction techniques and counsel patients on their individual risk of subsequent chondral degeneration.

Biomechanical analysis of the knee with partial anterior cruciate ligament disruption: quantitative evaluation using an electromagnetic measurement system

PURPOSE

To investigate the biomechanical function of anterior cruciate ligament (ACL) remnants in ACL-deficient knees with both partial and complete tears.

METHODS

Twenty partial ACL-deficient (group P), 20 complete ACL-deficient (group C), and 40 contralateral ACL-intact knees were examined. The end point during the Lachman test, side-to-side differences of KT-1000 measurements, and the pivot shift test were evaluated. Additionally, the side-to-side difference of anterior tibial translation during the Lachman test and the acceleration during the pivot shift test were calculated using an electromagnetic measurement system (EMS).

RESULTS

The end point was found in 9 patients in group P, whereas it was not detected in group C. In KT-1000 measurements, the mean side-to-side differences were 3.8 ± 2.4 mm in group P and 5.4 ± 2.3 mm in group C. There was a significant difference between these 2 groups (P < .05). In the pivot shift test evaluation in group P, one patient was evaluated as grade 0, 17 patients as grade 1+, and 2 patients as grade 2+. In group C, 10 patients were evaluated as grade 1+, 9 patients as grade 2+, and one patient as grade 3+. Using the EMS, mean side-to-side differences during the Lachman test were 3.1 ± 2.1 mm in group P and 7.2 ± 3.2 mm in group C. The anterior-posterior displacement in group P was significantly less than that in group C (P < .05). In the quantitative pivot shift test, the mean acceleration in the contralateral ACL-intact knees was -632.7 ± 254.5 mm/s(2), whereas it was -1107.5 ± 398.9 mm/s(2) in group P and -1652.2 ± 754.9 mm/s(2) in group C. Significant differences were detected between the 3 knee conditions (P < .05).

CONCLUSIONS

The quantitative assessments of knees with partial ACL ruptures during the Lachman test and the pivot shift test using the EMS showed less laxity than did knees with complete ACL tears, whereas their laxity was greater than the contralateral knees with intact ACLs.

LEVEL OF EVIDENCE

Level III, diagnostic study of nonconsecutive patients.

The diagnostic value of clinical tests, magnetic resonance imaging, and instrumented laxity in the differentiation of complete versus partial anterior cruciate ligament tears

PURPOSE

To evaluate the question of whether different arthroscopically confirmed anterior cruciate ligament (ACL) injury patterns have distinctive preoperative findings on clinical examination, instrumented laxity, and magnetic resonance imaging (MRI).

METHODS

Three hundred consecutive ACL-deficient patients with isolated ACL tears were evaluated with the Lachman test (LT), the pivot-shift test (PST), stress radiographs using the Telos Stress Device (Metax, Hungen, Germany), and MRI. After arthroscopic confirmation of the ACL injury, we grouped patients into 4 different ACL tear types (complete, partial anteromedial [AM] bundle intact, posterolateral [PL] bundle intact, and posterior cruciate ligament [PCL] healing), and partial tears were further evaluated for mechanical integrity and functionality of the remaining fibers.

RESULTS

PST grades of +2 and +3 were consistent with complete ACL tears (86%; P < .00001), whereas PST grades of 0 or +1 were strongly related to partial tears (76%; P < .00001). Instrumented laxity results showed a significant difference in side-to-side difference (SSD) of anterior tibial translation in complete tears (9.1 ± 3.4 mm) versus partial tears (5.2 ± 2.9 mm; P < .0001). Most PL-intact cases were "functional" (67%), with lower instrumented laxity values (SSD, 4.3 ± 2.3 mm) than the "nonfunctional" cases (SSD, 6.7 ± 2.9 mm; P < .001). The contrary was not observed for AM-intact cases (17% functional). Partial ACL tears with functional remaining fibers had PST grades of 0 or +1 and less than a 4 mm SSD in stress radiographs (sensitivity, 0.76; specificity, 0.90). Partial ACL tears with nonfunctional fibers had positive PST results and an SSD of anterior tibial displacement from 4 to 9 mm (sensitivity, 0.56; specificity, 0.92). Positive PST results and an SSD greater than 9 mm was recorded in complete ACL tears (sensitivity, 0.88; specificity, 0.96). MRI analysis revealed overlapping results between complete and partial tears.

CONCLUSIONS

Preoperative evaluation of different ACL tear types showed differences between complete and partial ACL tears with functional fibers in clinical examination and instrumented laxity tests. The combination of clinical tests and stress radiographs produced threshold values that distinguished complete from partial ACL tears, which may help the surgeon in the early identification of the presence of remaining functional fibers.

LEVEL OF EVIDENCE

Level III, case-control study.