High-demand tasks show that ACL reconstruction is not the only factor in controlling range of tibial rotation: a preliminary investigation

BACKGROUND

Excessive range of tibial rotation (rTR) may be a reason why athletes cannot return to sports after ACL reconstruction (ACLR). After ACLR, rTR is smaller in reconstructed knees compared to contralateral knees when measured during low-to-moderate-demand tasks. This may not be representative of the amount of rotational laxity during sports activities. The purpose of this study is to determine whether rTR is increased after ACL injury compared to the contralateral knee and whether it returns to normal after ACLR when assessed during high-demand hoptests, with the contralateral knee as a reference.

METHODS

Ten ACL injured subjects were tested within three months after injury and one year after reconstruction. Kinematic motion analysis was conducted, analysing both knees. Subjects performed a level-walking task, a single-leg hop for distance and a side jump. A paired t-test was used to detect a difference between mean kinematic variables before and after ACL reconstruction, and between the ACL-affected knees and contralateral knees before and after reconstruction.

RESULTS

RTR was greater during high-demand tasks compared to low-demand tasks. Pre-operative, rTR was smaller in the ACL-deficient knees compared to the contralateral knees during all tests. After ACLR, a greater rTR was seen in ACL-reconstructed knees compared to pre-operative, but a smaller rTR compared to the contralateral knees, even during high-demand tasks.

CONCLUSION

The smaller rTR, compared to the contralateral knee, seen after a subacute ACL tear may be attributed to altered landing technique, neuromuscular adaptation and fear of re-injury. The continued reduction in rTR one year after ACLR may be a combination of this neuromuscular adaptation and the biomechanical impact of the reconstruction.

TRIAL REGISTRATION

The trial was registered in the Dutch Trial Register (NTR: www.trialregister.nl , registration ID NL7686).

Comparison of Anterior Cruciate Ligament Reconstruction With Versus Without Anterolateral Augmentation: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background

It is clear that the anterolateral ligament has an important role in rotational knee stability. However, whether patients undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) can benefit from anterolateral augmentation (ALA) is still controversial.

Purpose

To compare the effects of isolated ACLR versus ACLR combined with ALA (ACLR+ALA) on clinical outcomes and knee stability.

Study Design

Systematic review; Level of evidence, 1.

Methods

The methodology followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A literature search of the PubMed, Embase, and Cochrane Library Central Register of Controlled Trials databases was undertaken to identify all randomized controlled trials (RCTs) comparing isolated ACLR with ACLR+ALA for the treatment of ACL injuries in the last 15 years. The Cochrane Collaboration risk-of-bias tool and the revised Jadad scale were utilized by 2 independent reviewers to determine the quality of RCTs. Relevant data were extracted and compared between procedures, and heterogeneity across the RCTs was assessed using the I ² statistic.

Results

The initial search yielded 849 articles. A total of 14 studies (1850 patients; 941 ACLR and 909 ACLR+ALA) satisfied the eligibility criteria for the meta-analysis. There were no significant differences between the procedures in terms of patient-reported outcomes (International Knee Documentation Committee score, Tegner score, Knee injury and Osteoarthritis Outcome Score) or return-to-sport rates. However, patients who underwent ACLR+ALA had better knee stability based on the pivot-shift test (risk ratio [RR], 1.06 [95% CI, 1.02 to 1.10]; P = .0008), Lachman test (RR, 1.03 [95% CI, 1.00 to 1.07]; P = .04), and side-to-side difference in anterior laxity (standardized mean difference, -0.55 [95% CI, -0.98 to -0.12]; P = .01) as well as a lower incidence of graft failure (RR, 0.30 [95% CI, 0.19 to 0.45]; P < .01) compared with patients who underwent isolated ACLR.

Conclusion

ALA can be considered as a reinforcement of ACLR to improve anteroposterior and anterolateral rotational stability of the knee and reduce the risk of failure. The patient-reported outcomes of isolated ACLR were similar to those of ACLR+ALA, and both procedures provided improved knee function.

Effects of Anterolateral Structure Augmentation on the In Vivo Kinematics of Anterior Cruciate Ligament-Reconstructed Knees

BACKGROUND

Double-bundle anterior cruciate ligament (ACL) reconstruction (ACLR) is a well-known treatment that restores the stability of ACL-deficient knees. However, some isolated ACL-reconstructed knees ultimately show rotatory laxity and develop osteoarthritis. Whether combined ACLR with anterolateral structure (ALS) augmentation (ALSA) can provide better improvement in the in vivo knee rotational kinematics remains unknown.

HYPOTHESIS

When compared with isolated double-bundle ACLR, combined double-bundle ACLR with ALSA can improve knee in vivo rotational kinematics and provide better restoration of knee kinematics.

STUDY DESIGN

Controlled laboratory study.

METHODS

Sixteen patients with unilateral ACL injury were randomly divided into 2 groups to receive either combined double-bundle ACLR and ALSA (ALSA group) or isolated double-bundle ACLR (ACLR group). All patients performed a single-leg lunge using the operative and nonoperative/contralateral legs under dual-fluoroscopic imaging system surveillance during a hospital visit at a minimum 1 year (12-13 months) of follow-up to assess the 6 degrees of freedom knee kinematics. Functional evaluation using the Lysholm and Marx rating scales and clinical examinations were also performed.

RESULTS

From full extension to approximately 90° of knee flexion at 5° intervals, the mean ± SD internal rotation of the reconstructed knees in the ALSA group (1.5°± 0.9°) was significantly smaller than that of the contralateral knees (8.2°± 1.9°; P = .008). The ALSA group knees also showed significantly (P = .045) more medial translation than the contralateral knees. In the ACLR group, the mean internal rotation of the reconstructed knee (6.0°± 2.1°) was significantly smaller than that of the contralateral knees (8.9°± 0.6°; P < .001). At full extension, the tibia was significantly more externally rotated than that of the contralateral legs (0.5°± 7.4° vs 7.6°± 3.4°, P = .049).

CONCLUSION

When compared with isolated double-bundle ACLR, double-bundle ACLR augmented with ALS reconstruction resulted in anterolateral rotatory overconstraint during the lunge motion.

CLINICAL RELEVANCE

Additional ALSA of double-bundle ACL-reconstructed knees overconstrained rotatory stability. Therefore, the use of ALSA for ACL-reconstructed knees should be considered with caution for patients with ACL deficiency and anterolateral rotatory instability. Longer-term follow-up to evaluate long-term outcomes and altered kinematics over time is recommended.

Minimally Invasive Modified Lemaire Tenodesis

Increasing emphasis in the literature is recently being put on controlling rotational stability in patients with an anterior cruciate ligament rupture by addressing the anterolateral complex during anterior cruciate ligament reconstruction. Many different techniques for lateral extra-articular tenodesis have been described, with the (modified) Lemaire technique being widely favored. Recent literature does report that lateral extra-articular tenodesis leads to a reduction in persistent rotatory laxity and graft rupture rate, but also may be associated with increased pain, reduced quadriceps strength, reduced subjective functional recovery, and cosmetic complaints. Thus this article aims to describe our minimally invasive technique for a modified Lemaire tenodesis.

The Femoral Footprint Position of the Anterior Cruciate Ligament Might Be a Predisposing Factor to a Noncontact Anterior Cruciate Ligament Rupture

BACKGROUND

Although the femoral tunnel position is crucial to anatomic single-bundle anterior cruciate ligament (ACL) reconstruction, the recommendations for the ideal femoral footprint position are mostly based on cadaveric studies with small sample sizes, elderly patients with unknown ACL status, and 2-dimensional techniques. Furthermore, a potential difference in the femoral ACL footprint position and ACL orientation between ACL-ruptured and ACL-intact knees has not been reported in the literature.

HYPOTHESIS

The femoral ACL footprint position and ACL orientation vary significantly between ACL-ruptured and matched control ACL-intact knees.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Magnetic resonance images of the knees of 90 patients with an ACL rupture and 90 matched control participants who had a noncontact knee injury without an ACL rupture were used to create 3-dimensional models of the femur and tibia. The ACL footprints were outlined on each model, and their positions (normalized to the lateral condyle width) as well as ACL orientations were measured with an anatomic coordinate system.

RESULTS

The femoral ACL footprint in patients with an ACL rupture was located at 36.6% posterior and 11.2% distal to the flexion-extension axis (FEA). The ACL orientation was 46.9° in the sagittal plane, 70.3° in the coronal plane, and 20.8° in the transverse plane. The ACL-ruptured group demonstrated a femoral ACL footprint position that was 11.0% more posterior and 7.7% more proximal than that of the control group (all P < .01). The same patients also exhibited 5.7° lower sagittal elevation, 3.1° higher coronal plane elevation, and 7.9° lower transverse plane deviation (all P < .01). The optimal cutoff value of the femoral ACL footprint position to prevent an ACL rupture was at 30% posterior and 12% distal to the FEA.

CONCLUSION

The ACL femoral footprint position might be a predisposing factor to an ACL rupture. Patients with a >30% posterior and <12% distal position of the femoral ACL footprint from the FEA might have a 51.2-times increased risk of an ACL rupture.

Biomechanical Comparison of Anterolateral Procedures Combined With Anterior Cruciate Ligament Reconstruction

BACKGROUND

Anterolateral soft tissue structures of the knee have a role in controlling anterolateral rotational laxity, and they may be damaged at the time of anterior cruciate ligament (ACL) ruptures.

PURPOSE

To compare the kinematic effects of anterolateral operative procedures in combination with intra-articular ACL reconstruction for combined ACL plus anterolateral-injured knees.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve cadaveric knees were tested in a 6 degrees of freedom rig using an optical tracking system to record the kinematics through 0° to 90° of knee flexion with no load, anterior drawer, internal rotation, and combined loading. Testing was first performed in ACL-intact, ACL-deficient, and combined ACL plus anterolateral-injured (distal deep insertions of the iliotibial band and the anterolateral ligament [ALL] and capsule cut) states. Thereafter, ACL reconstruction was performed alone and in combination with the following: modified MacIntosh tenodesis, modified Lemaire tenodesis passed both superficial and deep to the lateral collateral ligament, and ALL reconstruction. Anterolateral grafts were fixed at 30° of knee flexion with both 20 and 40 N of tension. Statistical analysis used repeated-measures analyses of variance and paired t tests with Bonferroni adjustments.

RESULTS

ACL reconstruction alone failed to restore native knee kinematics in combined ACL plus anterolateral-injured knees ( P < .05 for all). All combined reconstructions with 20 N of tension, except for ALL reconstruction ( P = .002-.01), restored anterior translation. With 40 N of tension, the superficial Lemaire and MacIntosh procedures overconstrained the anterior laxity in deep flexion. Only the deep Lemaire and MacIntosh procedures-with 20 N of tension-restored rotational kinematics to the intact state ( P > .05 for all), while the ALL underconstrained and the superficial Lemaire overconstrained internal rotation. The same procedures with 40 N of tension led to similar findings.

CONCLUSION

In a combined ACL plus anterolateral-injured knee, ACL reconstruction alone failed to restore intact knee kinematics. The addition of either the deep Lemaire or MacIntosh tenodesis tensioned with 20 N, however, restored native knee kinematics.

CLINICAL RELEVANCE

The current study indicates that unaddressed anterolateral injuries, in the presence of an ACL deficiency, result in abnormal knee kinematics that is not restored if only treated with intra-articular ACL reconstruction. Both the modified MacIntosh and modified deep Lemaire tenodeses (with 20 N of tension) restored native knee kinematics at time zero.

Single-bundle anterior cruciate ligament reconstruction: a comparison of conventional, central, and horizontal single-bundle virtual graft positions

BACKGROUND

Conventional endoscopic single-bundle transtibial anterior cruciate ligament (ACL) reconstruction from the posterolateral tibial footprint to the anteromedial femoral footprint results in a vertical graft. A more oblique horizontal graft from the anteromedial tibial footprint to the posterolateral femoral footprint may offer a better alternative for all endoscopic ACL reconstruction.

HYPOTHESIS

When compared with a conventional ACL single-bundle position, the horizontal graft ACL position has more obliquity and so undergoes a greater change in length during anterior translation and internal rotation.

STUDY DESIGN

Controlled laboratory study.

METHODS

A computer navigation system was used to acquire kinematic data during a flexion-extension cycle and outline the anteromedial and posterolateral aspects of the tibial and femoral footprints on 5 fresh-frozen cadaveric knees. Three virtual graft positions were defined: conventional (posterolateral tibia-anteromedial femur), central, and horizontal (anteromedial tibia- posterolateral femur). After transection of the ACL, the obliquity, anisometry, absolute length change, and apparent strain were computed for each graft position during the Lachman test, the anterior drawer test, and internal rotation at 0 degrees and 30 degrees of flexion.

RESULTS

The horizontal position was more oblique than the other positions (P < .05). There were no differences in anisometry. The horizontal position elongated more than the other positions during the Lachman test (P < .05) and more than the conventional position during the anterior drawer test (P = .009). During internal rotation at 30 degrees flexion, the horizontal position elongated more than the other positions (P < .05). The central and horizontal positions had more apparent strain than that of the vertical position during the Lachman test and internal rotation (P < .05); no significant difference was found during the anterior drawer test.

CONCLUSION

In ACL-deficient cadaveric knees, the horizontal graft position has greater obliquity and so undergoes greater elongation without increased apparent strain when compared to the central graft position, in response to anterior translation and internal rotation maneuvers.

CLINICAL RELEVANCE

Horizontal graft placement of a single-bundle ACL may result in greater control of translation and rotation.

The pivot-shift phenomenon during computer-assisted anterior cruciate ligament reconstruction

Anterior cruciate ligament reconstruction was one of the first procedures in which computer-assisted techniques were used in orthopaedic surgery. However, the use of navigation for tunnel placement in anterior cruciate ligament surgery remains problematic, as the optimal position for placement of the tunnels is debatable. The technical specification of tunnel position is clinically relevant, but the targets and tolerances for this technical specification are poorly understood. The inability to reliably quantify knee kinematics and stability before, during, or after anterior cruciate ligament reconstruction remains a problem. A navigated examination to assess knee stability could potentially close the computer-assisted surgery treatment loop by providing quantitative feedback about various reconstruction techniques. Recent iterations of navigated examinations for the assessment of stability include even complex pathologic movements, such as those detected with the pivot-shift examination. In this paper, we review conventional stability measurements of the knee and compare them with navigated techniques, with a focus on the navigated pivot-shift examination. In summary, direct intraoperative measurements and quantifications of knee stability, including the pivot-shift phenomenon, are now possible with the use of navigation. Consequently, more reproducible and clinically meaningful quantification of the pivot-shift phenomenon may allow for more accurate evaluation of various anterior cruciate ligament reconstruction techniques in the future.

Perspectives on computer-assisted orthopaedic surgery: movement toward quantitative orthopaedic surgery

The fundamental goal of computer-assisted surgery is to make orthopaedic surgery patient-specific, minimally invasive, and quantitative. The components of computer-assisted surgery include preoperative imaging and planning, intraoperative execution, and postoperative evaluation. Ideally, these components are integrated such that sophisticated diagnostic technologies are used to create a patient-specific surgical plan. This plan is then programmed into a computer-assisted intraoperative system so that it can be precisely executed. Finally, the patient outcome is tracked longitudinally in a quantitative fashion. Computer-assisted surgery relies on the use of quantitative data rather than surgeon feel and intuition to facilitate clinical decision-making. As surgeons rely more on quantitative feedback, they must establish appropriate specifications for various operations. These specifications should be clinically relevant and must have known targets and tolerances. This overview provides examples of quantitative surgery as applied in navigated total knee replacement and anterior cruciate ligament reconstruction and in the more recent indication of robotic unicondylar knee replacement. Computer-assisted surgery represents a set of tools that facilitate quantitative surgery. To effectively use these tools, however, one must identify technical specifications that are clinically relevant for the various procedures; these specifications must be associated with known target values and tolerances and must have the capability of being reliably measured by computer-assisted surgery tools. Clinical and basic-science research is necessary to better define technical specifications for navigated procedures.

Changes in the length of virtual anterior cruciate ligament fibers during stability testing: a comparison of conventional single-bundle reconstruction and native anterior cruciate ligament

BACKGROUND

Conventional tunnel positions for single-bundle (SB) transtibial anterior cruciate ligament (ACL) reconstruction are located in the posterolateral (PL) tibial footprint and the anteromedial (AM) femoral footprint, resulting in an anatomic mismatch graft that is more vertical than native fibers. This vertical mismatch position may significantly influence the ability of an ACL graft to stabilize the knee.

HYPOTHESIS

Anatomic ACL fibers undergo a greater change in length during anterior translation and internal rotation than a conventional SB reconstruction from the PL tibial footprint to the AM femoral footprint.

STUDY DESIGN

Controlled laboratory study.

METHODS

The Praxim ACL Surgetics navigation system was used to acquire kinematic data during a flexion/extension cycle and to register all points within the ACL footprint from 5 fresh-frozen cadaveric knees. Virtual fibers were placed in the center of the AM and PL bundles as well as central and conventional SB positions. After transection of the ACL, the absolute length change and apparent strain of the fibers were computed for each knee during the Lachman and anterior drawer tests and internal rotation at 0 degrees and 30 degrees of flexion.

RESULTS

Each of the anatomic fibers (AM, PL, and central) had more elongation and apparent strain than the conventional SB fiber during the Lachman maneuver. During the anterior drawer test, the AM and central (but not the PL) fibers lengthened significantly more and the AM had more apparent strain than the conventional SB fiber. During internal rotation at 0 degrees and 30 degrees of flexion, anatomic fibers elongated significantly more than the conventional fiber. Except for the AM fiber with the knee at full extension, apparent strain was greater in all anatomic fibers than in the conventional SB fiber during internal rotation maneuvers.

CONCLUSION

In ACL-deficient cadaveric knees, anatomic fibers undergo greater elongation and apparent strain in response to anterior translation and internal rotation maneuvers than a conventional SB graft. Because of their optimal orientation, anatomic fibers may resist pathologic anterior translation and internal rotation more than the conventional SB position.

CLINICAL RELEVANCE

Conventional placement of a single-bundle graft results in suboptimal changes in fiber length and strain, suggesting that alternatives such as anatomic placement of an SB graft or double-bundle reconstruction may result in greater control of translation and rotation.