ACL reconstruction: a meta-analysis of functional scores

Editorial Commentary: Noninferiority of Anterior Cruciate Ligament Repair With Dynamic Intraligamentary Stabilization at Short- to Mid-Term Follow-Up Does Not Justify Superseding Anterior Cruciate Ligament Reconstruction as the "Gold Standard" for Anterior Cruciate Ligament Surgery

With advances in surgical technology, including the introduction of some kind of mechanical augmentation, there has been a resurgence of interest in primary repair of the anterior cruciate ligament (ACL). If successful, ACL repairs may provide several advantages over reconstruction resulting from the preservation of the native anatomy and proprioception. Recently, augmentation of ACL repair using dynamic intraligamentary stabilization (DIS) has been proposed, to create an optimal biomechanical environment for healing. In the DIS technique, an additional nonresorbable cord is placed along the ACL and attached to a dynamic spring fixed in the proximal tibia, keeping the tibia in a posterior drawer position at every degree of flexion. The analyzed randomized controlled trials comparing ACL repair with DIS to ACL reconstruction found overall similar failure and revision rates, whereas the few observed statistically significant differences in functional scores or knee stability favoring either of the techniques were clearly not clinically relevant. Of course, repair of a torn ACL should be limited to a specific subset of patients presenting with an acute femoral avulsion tear with minimal retraction and good tissue quality. However, the present short- to mid-term results do not justify ACL reconstruction to be superseded by ACL repair with DIS as the "gold standard" for surgical treatment of ACL tears in the future, even in this subset of patients.

Outcomes of Primary Anterior Cruciate Ligament (ACL) Repair for Proximal Tears: A Systematic Review and Meta-Analysis

The purpose of this study is to compare failure rates among different techniques of primary anterior cruciate ligament (ACL) repair for the treatment of proximal ACL ruptures. Meta-analysis and systematic review were completed, and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Studies from Embase, Cochrane, and PubMed published between June 2011 and June 2022 reporting outcomes of primary ACL repair on proximal tears with a minimum two-year follow-up were included. Primary ACL repair was divided into dynamic, static, and non-augmented repair. The primary outcome was failure rates, and the secondary outcomes included patient-reported outcomes (PROs) and anterior tibial stability (ATT). Eighteen studies on primary ACL repair were included, with a total of 614 patients (ages ranging from 6 to 65, 60% male). Only two studies were level 1 randomized controlled clinical trials. The static repair had a failure rate of 33 out of 261 (12.6%), non-augmented was 17 out of 179 (9.4%), and dynamic repair was 31 out of 174 (17.8%); no statistically significant difference was found comparing the failure rates (p = 0.090). PROs using the International Knee Documentation Committee (IKDC) and Lysholm scores had weighted averages of 91.7 (95% confidence interval (CI): 89.6-93.8) and 94.7 (95% CI: 92.7-96.7), respectively. ATT had a weighted average of 1.668 mm (95% CI: 1.002-2.334). The primary findings of this paper include a 12.6% combined failure rate for primary proximal ACL repair with no significant difference in failure rate or PROs when accounting for the methodology of repair at a minimum two-year follow-up. It is important to note the lack of high-quality randomized controlled trials, the heterogeneity of included studies, and the lack of long-term data. Despite these limitations, the findings of the current analysis suggest that primary repair may be a useful treatment option for indicated candidates with proximal ACL ruptures. Further long-term and higher-quality comparative studies on ACL reconstruction are warranted.

Race and Gender Differences in Anterior Cruciate Ligament Femoral Footprint Location and Orientation: A 3D-MRI Study

OBJECTIVE

The femoral tunnel position is crucial to anatomic single-bundle anterior cruciate ligament (ACL) reconstruction, but the ideal femoral footprint position are mostly based on small-sized cadaveric studies and elderly patients with a single ethnic background. This study aimed to identify potential race- or gender-specific differences in the ACL femoral footprint location and ACL orientation, determine the correlation between the ACL orientation and the femoral footprint location.

METHODS

Magnetic resonance images (MRIs) of 90 Caucasian participants and 90 matched Chinese subjects were used for reconstruction of three-dimensional (3D) femur and tibial models. ACL footprints were sketched by several experienced orthopedic surgeons on the MRI photographs. The anatomical coordinate system was applied to reflect the ACL footprint location and orientation of scanned samples. The femoral ACL footprint locations were represented by their distance from the origin in the anteroposterior (A/P) and distal-proximal (D/P) directions. The orientation of the ACL was described with the sagittal, coronal and transverse deviation angles. The ACL orientation and femoral footprint position were compared by the two-sided t-test. Multiple regression analysis was used to study the correlation between the orientation and femoral footprint position.

RESULTS

The average femur footprint A/P position was -6.6 ± 1.6 mm in the Chinese group and -5.1 ± 2.3 mm in the Caucasian group, (p < 0.001). The average femur footprint D/P position was -2.8 ± 2.4 mm in Chinese and - 3.9 ± 2.0 mm in Caucasians, (p = 0.001). The Chinese group had a mean difference of a 1.5 mm (6.1%) more posterior and 1.1 mm (5.3%) more proximal in the position from the flexion-extension axis (FEA). And the males have a sagittal plane elevation about 4-5° higher than females in both racial groups. Furthermore, for every 1% (0.40 mm) increase in A/P and D/P values, the sagittal angle decreased by about 0.12° and 0.24°, respectively; the coronal angle decreased by about 0.10° and 0.30°, respectively. For every 1% (0.40 mm) increase in D/P value, the transverse angle increased by about 0.14°.

CONCLUSION

The significant race- and gender-specific differences in the femoral footprint and orientation of the ACL should be taken in consideration during anatomic single-bundle ACL reconstruction. Furthermore, the quantitative relationship between the ACL orientation and the footprint location might provide some reference for surgeons to develop a surgical strategy in ACL single-bundle reconstruction and revision.

Reduced knee laxity and failure rate following anterior cruciate ligament reconstruction compared with repair for acute tears: a meta-analysis

BACKGROUND

Following anterior cruciate ligament (ACL) tears, both repair and reconstruction may be performed to restore joint biomechanics and proprioception. The present study compared joint laxity, patient-reported outcome measures (PROMs), and rate of failure following primary repair versus reconstruction for ACL ruptures.

METHODS

This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pubmed, Google scholar, Embase, and Web of Science were accessed in September 2022. All the clinical investigations comparing repair versus reconstruction for primary ACL tears were accessed. Studies reporting data on multiple ligament injuries settings were not eligible.

RESULTS

Data from eight articles (708 procedures) were collected. The mean length of the follow-up was 67.3 ± 119.4 months. The mean age of the patients was 27.1 ± 5.7 years. Thirty-six percent (255 of 708 patients) were women. The mean body mass index (BMI) was 24.3 ± 1.1 kg/m². The mean time span from injury to surgery was 36.2 ± 32.3 months. There was comparability at baseline with regards to instrumental laxity, Lachman test, International Knee Document Committee (IKDC), and Tegner Scale (P > 0.1). Similarity between ACL reconstruction and repair was found in IKDC (P = 0.2) and visual analog scale (VAS) satisfaction (P = 0.7). The repair group demonstrated greater mean laxity (P = 0.0005) and greater rate of failure (P = 0.004).

CONCLUSION

ACL reconstruction may yield greater joint stability and lower rate of failure compared with surgical repair. Similarity was found in PROMs.

LEVEL OF EVIDENCE

III.

Clinical outcomes and return to sport after single-stage revision anterior cruciate ligament reconstruction by bone-patellar tendon autograft combined with lateral extra-articular tenodesis

PURPOSE

The anterior cruciate ligament reconstruction (ACLR) failure rate continues to increase. Involvement of a young population with a desire to return to sport, explains the increased need for ACLR (revACLR) revision. The aim of this study was to evaluate clinical outcome, complications, failure rate and return to sport of a single-stage revACLR using bone patellar tendon-bone (BTBT) combined with lateral extra-articular tenodesis (LET).

MATERIAL AND METHODS

A retrospective analysis was performed on 36 patients who underwent revACLR. Knee stability was assessed by Lachman and Pivot shift test. Objective anterior laxity was determined by KT-2000 arthrometer. The IKDC subjective, Lysholm, ACL-RSI Scores, level of sport activity and Forgotten Joint Score-12 were recorded.

RESULTS

Of 36 patients, we collected data from 17 who underwent single-stage revACLR with autologous BTBT combined with LET, performed using an extra-articular MacIntosh procedure as modified by Arnold-Coker. The side-to-side difference in Lachman test and Pivot shift test significantly improved postoperatively. The subjective IKDC, Lysholm and ACL-RSI significantly improved from 71.4 ± 9.03 to 92 ± 6.9, from 58.3 ± 19.3 to 66.8 ± 27.7 and from 50.4 ± 12.2 to 68.6 ± 24.5, respectively during the post-operative follow-up. Ten patients (58.8%) returned to their desired level of sport. One patient was considered a failure because of the postoperative laxity.

CONCLUSION

Single-stage revACLR with BPTB combined with LET is a safe procedure that shows good objective and subjective outcomes, and a high rate of return to the same level of sport. Reducing rotational instability and strain on intra-articular reconstructed structures results in a low rate of complications and failure.

Lateral Extra-articular Tenodesis with Iliotibial Band Using Knotless All-Suture Anchor Femoral Fixation

Common injuries, such as anterior cruciate ligament (ACL) tears, can result in both anterior and rotational instability of the knee. An arthroscopic anterior cruciate ligament reconstruction (ACLR) method has been shown to be effective in restoring anterior translational stability, but this could be followed by persistent rotational instability by means of residual pivot shifts or repeat instability episodes. Alternative techniques, such as a lateral extraarticular tenodesis (LET), has been proposed as a technique for preventing persistent rotational instability following ACLR. This article presents a case of a LET using an autologous central slip of iliotibial (IT) band with fixation to the femur using a 1.8-mm knotless all-suture anchor.

Platelet-Rich Fibrin-Augmented Gap-Bridging Strategy in Rabbit Anterior Cruciate Ligament Repair

BACKGROUND

We assessed the efficacy of a novel platelet-rich fibrin (PRF)-augmented repair strategy for promoting biological healing of an anterior cruciate ligament (ACL) midsubstance tear in a rabbit model. The biological gap-bridging effect of a PRF scaffold alone or in combination with rabbit ligamentocytes on primary ACL healing was evaluated both in vitro and in vivo.

HYPOTHESIS

A PRF matrix can be implanted as a provisional fibrin-platelet bridging scaffold at an ACL defect to facilitate functional healing.

STUDY DESIGN

Controlled laboratory study.

METHODS

The biological effects of PRF on primary rabbit ligamentocyte proliferation, tenogenic differentiation, migration, and tendon-specific matrix production were investigated for treatment of cells with PRF-conditioned medium (PRFM). Three-dimensional (3D) lyophilized PRF (LPRF)-cell composite was fabricated by culturing ligamentocytes on an LPRF patch for 14 days. Cell-scaffold interactions were investigated under a scanning electron microscope and through histological analysis. An ACL midsubstance tear model was established in 3 rabbit groups: a ruptured ACL was treated with isolated suture repair in group A, whereas the primary repair was augmented with LPRF and LPRF-cell composite to bridge the gap between ruptured ends of ligaments in groups B and C, respectively. Outcomes-gross appearance, magnetic resonance imaging, and histological analysis-were evaluated in postoperative weeks 8 and 12.

RESULTS

PRFM promoted cultured ligamentocyte proliferation, migration, and expression of tenogenic genes (type I and III collagen and tenascin). PRF was noted to upregulate cell tenogenic differentiation in terms of matrix production. In the 3D culture, viable cells formed layers at high density on the LPRF scaffold surface, with notable cell ingrowth and abundant collagenous matrix depositions. Moreover, ACL repair tissue and less articular cartilage damage were observed in knee joints in groups B and C, implying the existence of a chondroprotective phenomenon associated with PRF-augmented treatment.

CONCLUSION

Our PRF-augmented strategy can facilitate the formation of stable repair tissue and thus provide gap-bridging in ACL repair.

CLINICAL RELEVANCE

From the translational viewpoint, effective primary repair of the ACL may enable considerable advancement in therapeutic strategy for ACL injuries, particularly allowing for proprioception retention and thus improved physiological joint kinematics.

Effect of Surgical Design Variations on the Knee Contact Behavior during Anterior Cruciate Ligament Reconstruction

In this study, we aimed to develop an in-silico synthesis of the effect of critical surgical design parameters on articular contact behavior for a bone-patellar-tendon-bone anterior cruciate ligament reconstruction (ACL-R) surgery. A previously developed finite element model of the knee joint consisting of all relevant soft tissues was employed. The knee model was further updated with additional features to develop the parametric FE model of the biomechanical experiments that depicted the ACL-R surgery. The parametricity was created involving femoral tunnel architecture (orientations and locations) and graft fixation characteristics (pretension and angle of fixation). A global sensitivity analysis based on variance decomposition was used to investigate the contribution of the surgical parameters to the uncertainty in response to the ACL-R joint. Our examinations indicated that the total contact force was primarily influenced by either combined or individual action of the graft pretension and fixation angle, with a modest contribution of the graft insertion sites. The joint contact center and area were affected mainly by the angle of fixation and the tunnel placements. Graft pretension played the dominant role in the maximum contact pressure variability, an observation that has been well-documented in the literature. Interestingly, the joint contact behavior was almost insensitive to the tunnel's coronal and sagittal orientations. Our data provide an evaluation of how the surgical parameters affect the knee joint's contact behavior after ACL-R and may provide additional information to better explain the occurrence of osteoarthritis as an aftermath of such surgery.

Simultaneous Arthroscopic Anterior Cruciate Ligament Reconstruction Using Double Suspensory Technique and Medial Open-Wedge, High Tibial Osteotomy

Anterior cruciate ligament reconstruction (ACLR) is generally performed regardless of knee malalignments. However, there are some indications for either staged or simultaneous ACL reconstruction and realignment procedures, such as high tibial osteotomy (HTO). Simultaneous HTO-ACL reconstruction has the apparent benefit of a single surgical procedure with a faster recovery than a staged procedure, and it produces good clinical outcomes. Several techniques have been described for simultaneous ACLR and medial open wedge HTO. The tibial tunnel preparation and graft fixation are the most challenging part of the procedure. Recent studies on comparison of fixation of tibial tunnel graft using suspensory fixation versus bioabsorbable screws have shown superior results of more bone preservation and less graft rupture. We assumed suspensory fixation on the tibial side with bone preservation might be more reliable in patients who received ACLR and open wedge HTO at the same time. Therefore, we described our technique of simultaneous open-wedge HTO and ACLR using double suspensory graft fixation.

Kinetic energy absorption differences during drop jump between athletes with and without radiological signs of knee osteoarthritis: Two years post anterior cruciate ligament reconstruction

BACKGROUND

Patients demonstrate decreased knee loading and energy absorption after anterior cruciate ligament reconstruction (ACLR). This study aimed to determine the differences in the contribution of joints to the absorbed energy between athletes with and without radiological signs of knee OA 2 years after ACLR during drop jump (DJ) landing from 20, 30, and 40 cm.

METHODS

Forty-one (level I/II) athletes 2 years after ACLR participated in this cross-sectional study and completed motion analysis testing of DJ. Proportional contribution of the joints (foot, ankle, knee, and hip) to the absorbed energy were computed. Posterior-anterior bent-knee radiographs were completed and graded in the medial compartment of the reconstructed knee using the Kellgren-Lawrence (KL) system (OA group: KL ≥2; Non-OA group: KL<2) RESULTS: Thirteen (31.7%) athletes showed radiological signs of knee OA in the medial compartment. There was a significant joint-by-group-by-limb interaction for the contribution of joints to absorbed energy during DJ 40 cm (p ≤ 0.019) and a joint-by-group interaction for the contribution of joints during DJ 20 cm (p = 0.018). The OA group had a lower involved knee (p = 0.043) and higher involved hip contributions (p = 0.014) compared to the Non-OA group, and the non-involved knee (p = 0.007). While the Non-OA group had a lower involved ankle contribution (p = 0.045) compared to their non-involved ankle during DJ 40 cm. The OA group also had higher involved hip contribution than the Non-OA group (p = 0.010), lower involved knee (p = 0.002), and higher involved hip contribution than the non-involved limb during DJ 20 cm.

SIGNIFICANCE

The OA group may have adopted a compensatory pattern characterized by a decreased involved knee and increased involved hip to attenuate absorbed energy compared to the Non-OA group and their non-involved limb. The contribution of joints to the absorbed energy during DJ landing might be used as an assessment tool to identify patients with radiological signs of knee OA after ACLR.

Twenty-Year Outcomes After Anterior Cruciate Ligament Reconstruction: A Systematic Review of Prospectively Collected Data

BACKGROUND

Several long-term (≥20 years) follow-up studies after anterior cruciate ligament (ACL) reconstruction have been published in recent years, allowing for a systematic evaluation of outcomes.

PURPOSE

To summarize outcomes at ≥20 years after ACL reconstruction and identify patient and surgical factors that affect these results.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

Prospective studies of primary ACL reconstructions with hamstring or bone-patellar tendon-bone (BTB) autograft via an arthroscopic or a mini-open technique and with a mean follow-up of ≥20 years were identified. When possible, the mean scores for each outcome measure were calculated. Factors identified in individual studies as predictive of outcomes were described.

RESULTS

Five studies met the inclusion and exclusion criteria with a total of 2012 patients. The pooled mean follow-up for patient-reported outcome measures was 44.2% (range, 29.6%-92.7%) and in-person evaluation was 33.2% (range, 29.6%-48.9%). Four studies (n = 584) reported graft tears at a mean rate of 11.8% (range, 2%-18.5%) and 4 studies (n = 773) reported a contralateral ACL injury rate of 12.2% (range, 5.8%-30%). Repeat non-ACL arthroscopic surgery (4 studies; n = 177) to the ipsilateral knee occurred in 10.4% (range, 9.5%-18.3%) and knee arthroplasty (1 study; n = 217) in 5%. The pooled mean of the International Knee Documentation Committee subjective knee function (IKDC) score was 79.1 (SD, 21.8 [3 studies; n = 644]). In 2 studies (n?= 221), 57.5% of patients continued to participate in strenuous activities. The IKDC-objective score was normal or nearly normal in 82.3% (n = 496; 3 studies), with low rates of clinically significant residual laxity. Moderate-severe radiographic osteoarthritis (OA) (IKDC grade C or D) was present in 25.9% of patients (n = 605; 3 studies). Medial meniscectomy is associated with increased risk of radiographic OA. Radiographic OA severity is associated with worse patient-reported knee function, but the association with knee pain is unclear.

CONCLUSION

Currently available prospective evidence for ACL reconstruction with hamstring or BTB autograft provides several insights into outcomes at 20 years. The rates of follow-up at 20 years range from 30% to 93%. IKDC-objective scores were normal or nearly normal in 82% and the mean IKDC-subjective score was 79 points.

Is 12 months enough to reach function after athletes' ACL reconstruction: a prospective longitudinal study

CONTEXT

Anterior Cruciate Ligament (ACL) injury is disabling in several sports because it causes knee instability and functional deficit. Usually, surgical treatments produce the best functional outcomes, however, sometimes they are not always able to fully restore stability and function.

OBJECTIVE

The objective of this study was to evaluate postural balance, muscle strength, and functional performance of young athletes with an ACL injury before and after ACL reconstruction.

DESIGN

This was a longitudinal observational prospective study.

METHOD

74 athletes, 60 men, and 14 women, aged between 16 and 45, divided into two groups: the Group-Lesion of ACL with 34 athletes (24.1 years) and the Group-Control with 40 athletes without ACL lesion (27.7 years old). All volunteers performed posturography, isokinetic dynamometry, and the Hop-Test. The ACL-Group was evaluated before and 12 months after the reconstruction and the control group was evaluated once.

RESULTS

The Postoperative ACL Group presented greater limb symmetry, 0.96 (± 0.12), than the preoperative ACL Group, 0.87 (± 0.17), p < 0.01 in the Hop-Test. In the posturography, the displacement area was smaller in the postoperative ACL Group, 19.85 (± 5.74), compared to the preoperative ACL Group, 24.20 (± 8.97), p < 0.01. In isokinetic dynamometry the torque peak was greater in the postoperative ACL Group, 0.91 (± 0.14), than in the preoperative ACL Group, 0.74 (± 0.15), p < 0.01.

CONCLUSION

The functional outcomes increased in ACL reconstruction athletes after 12 months, but not at the same level as in the Control Group. The result indicates an incomplete functional recovery, adaptive changes in postural control after injury, reconstruction, and return to sport.

Anterior cruciate ligament (ACL) repair using cortical or anchor fixation with suture tape augmentation vs ACL reconstruction: A comparative biomechanical analysis

BACKGROUND

The purpose was to compare knee kinematics in a cadaveric model of anterior cruciate ligament (ACL) repair using an adjustable-loop femoral cortical suspensory (AL-CSF) or independent bundle suture anchor fixation (IB-SAF) with suture tape augmentation to a bone-patellar tendon-bone (BPTB) ACL reconstruction.

METHODS

Twenty-seven cadaveric knees were randomly assigned to one of three surgical techniques: (1) ACL repair using the AL-CSF technique with suture tape augmentation, (2) ACL repair using the IB-SAF technique with suture tape augmentation, (3) ACL reconstruction using a BPTB autograft. Each specimen underwent three conditions according to the state of the ACL (native, proximal transection, repair/reconstruction) with each condition tested at four different angles of knee flexion (0°, 30°, 60°, 90°). Anterior tibial translation (ATT) and internal tibial rotation (ITR) were evaluated using 3-dimensional motion tracking software.

RESULTS

ACL transection resulted in a significant increase in ATT and ITR when compared to the native state (P < 0.001, respectively). ACL repair with the AL-CSF or IB-SAF technique as well as BPTB reconstruction restored native ATT and ITR at all tested angles of knee flexion, while showing significantly less ATT at 0°, 30°, 60°, and 90° as well as significantly less ITR at 30°, 60°, and 90° of knee flexion when compared to the ACL-deficient state. There were no significant differences in ATT and ITR between the three techniques utilized.

CONCLUSION

ACL repair using the AL-CSF or IB-SAF technique with suture tape augmentation as well as BPTB ACL reconstruction each restored native anteroposterior and rotational laxity, without significant differences in knee kinematics between the three techniques utilized.

LEVEL OF EVIDENCE

Controlled Laboratory Study.

Revision Anterior Cruciate Ligament Reconstruction after Surgical Management of Multiligament Knee Injury

The purpose of this study is to determine factors associated with the need for revision anterior cruciate ligament reconstruction (ACLR) after multiligament knee injury (MLKI) and to report outcomes for patients undergoing revision ACLR after MLKI. This involves a retrospective review of 231 MLKIs in 225 patients treated over a 12-year period, with institutional review board approval. Patients with two or more injured knee ligaments requiring surgical reconstruction, including the ACL, were included for analyses. Overall, 231 knees with MLKIs underwent ACLR, with 10% (n = 24) requiring revision ACLR. There were no significant differences in age, sex, tobacco use, diabetes, or body mass index between cohorts requiring or not requiring revision ACLR. However, patients requiring revision ACLR had significantly longer follow-up duration (55.1 vs. 37.4 months, p = 0.004), more ligament reconstructions/repairs (mean 3.0 vs. 1.7, p < 0.001), more nonligament surgeries (mean 2.2 vs. 0.7, p = 0.002), more total surgeries (mean 5.3 vs. 2.4, p < 0.001), and more graft reconstructions (mean 4.7 vs. 2.7, p < 0.001). Patients in both groups had similar return to work (p = 0.12) and activity (p = 0.91) levels at final follow-up. Patients who had revision ACLR took significantly longer to return to work at their highest level (18 vs. 12 months, p = 0.036), but similar time to return to their highest level of activity (p = 0.33). Range of motion (134 vs. 127 degrees, p = 0.14), pain severity (2.2 vs. 1.7, p = 0.24), and Lysholm's scores (86.3 vs. 90.0, p = 0.24) at final follow-up were similar between groups. Patients requiring revision ACLR in the setting of a MLKI had more overall concurrent surgeries and other ligament reconstructions, but had similar final outcome scores to those who did not require revision surgery. Revision ligament surgery can be associated with increased pain, stiffness, and decrease patient outcomes. Revision surgery is often necessary after multiligament knee reconstructions, but patients requiring ACLR in the setting of a MLKI have good overall outcomes, with patients requiring revision ACLR at a rate of 10%.

A Systematic Approach for Stronger Documentation of Anterior Cruciate Ligament Graft Choice

Numerous studies have focused on determining the optimal choice between the two most used anterior cruciate ligament (ACL) reconstruction autografts. In order to address this matter, we performed a systematic review of every meta-analysis published on the PubMed platform between 2001 and 2020, comparing the functional outcomes, the static stability parameters, as well as the postoperative and long-term complications of the patellar tendon (BPTB) autograft and hamstrings (HT). We retrieved a total of 26 meta-analyses that met our criteria, and the characteristics and outcomes of every meta-analysis, as well as subgroup analysis regarding the type of the study design, number of strands of HT autograft, and fixation method, were extensively recorded. The majority of the meta-analyses showed that there were no significant differences between BPTB and HT in terms of functional outcomes and static stability parameters while HT autografts seem to be superior to BPTB regarding kneeling pain and anterior knee pain. Other outcomes seem to be affected by the number of strands of the HT autograft, the fixation technique, and the type of study design, indicating superiority of the four-strand HT autograft with the use of an extra-cortical button fixation. Overall, there is no clear superiority of BPTB over HT autografts for ACL reconstruction, as both types present similar outcomes in the majority of postoperative parameters. Autograft selection should be individualized according to each patient's needs and more RCTs are warranted in order to reach safer results on the appropriate autograft type.

The Effect of Anterior Cruciate Ligament Reconstruction with an Electropsun Scaffold on Tibiofemoral Contact Mechanics

Surgical reconstruction of the torn ACL is performed to restore native contact mechanics. Drawbacks to traditional ACL repair techniques motivate the development of a tissue engineered ACL scaffold. Our group has developed a hierarchical electrospun polycaprolactone (PCL) scaffold that consists of rolled nanofiber bundles attached at each end with solvent-case blocks of PCL. The goal of this study was to compare ovine cadaver tibiofemoral contact mechanics after ACL reconstruction with the electrospun scaffold to a clinically applicable ACL reconstruction with a soft tissue graft and the ACL transected condition (ACLX). In the ACLX group and after ACL reconstruction with either the electrospun scaffold or soft tissue graft, pressure sensors were inserted under the menisci. Loads up to 890 N were applied at various flexion angles. The scaffold performed the best at restoring contact mechanics in the medial hemijoint to that of the native ACL. The scaffold was good at maintaining a medial-lateral balance of pressures as in the native joint whereas the ACLX shifted pressure off the lateral and on to the medial hemijoint. While the ACL scaffold didn't restore mechanics to that of the native condition, it improved contact mechanics compared to the standard graft replacement and ACLX condition.

ADSC-Based Cell Therapies for Musculoskeletal Disorders: A Review of Recent Clinical Trials

Recently published clinical trials involving the use of adipose-derived stem cells (ADSCs) indicated that approximately one-third of the studies were conducted on musculoskeletal disorders (MSD). MSD refers to a wide range of degenerative conditions of joints, bones, and muscles, and these conditions are the most common causes of chronic disability worldwide, being a major burden to the society. Conventional treatment modalities for MSD are not sufficient to correct the underlying structural abnormalities. Hence, ADSC-based cell therapies are being tested as a form of alternative, yet more effective, therapies in the management of MSDs. Therefore, in this review, MSDs subjected to the ADSC-based therapy were further categorized as arthritis, craniomaxillofacial defects, tendon/ligament related disorders, and spine disorders, and their brief characterization as well as the corresponding conventional therapeutic approaches with possible mechanisms with which ADSCs produce regenerative effects in disease-specific microenvironments were discussed to provide an overview of under which circumstances and on what bases the ADSC-based cell therapy was implemented. Providing an overview of the current status of ADSC-based cell therapy on MSDs can help to develop better and optimized strategies of ADSC-based therapeutics for MSDs as well as help to find novel clinical applications of ADSCs in the near future.

Occurrence of inadequate ACL healing after Dynamic Intraligamentary Stabilization and functional outcome-a multicentre case series

Introduction

Dynamic Intraligamentary Stabilization (DIS) is a technique for preservation, anatomical repair and stabilization of a freshly injured anterior cruciate ligament (ACL). The main purpose of this study was to evaluate the short-term re-operation rate when compared to traditional autograft reconstruction.

Methods

Four, from the developer independent, centres enrolled patients that underwent ACL repair by DIS, according to the specific indications given by MRI imaging at a minimum follow-up of 12 months. The re-operation rate was recorded as primary outcome. Secondary outcome measures were the postoperative antero-posterior knee laxity (using a portable Rolimeter®), as well as the Tegner, Lysholm and IKDC Scores.

Results

A total of 105 patients were investigated with a median follow-up of 21 months. Thirteen patients were lost to follow-up. Of the remaining 92 patients 15 (16.3%) had insufficient functional stability and required subsequent ACL reconstruction. These patients were excluded from further analysis, leaving 77 consecutive patients for a 12 months follow-up. The median age at time of surgery was 30 years for that group. At time of follow-up a median antero-posterior translation difference of 2 mm was measured. None of these patients reported subjective insufficiency (giving way), but in 14 patients (18.2%), the difference of antero-posterior translation was more than 3 mm. We found a median Tegner Score of 5.5, a median Lysholm Score of 95.0 and a median IKDC Score of 89.4.

Conclusion

The main finding of this multicentre study is a relevant re-operation rate of 16.3%. Another 18.2% showed objective antero-posterior laxity (≥ 3 mm) during testing raising the suspicion of postoperative non-healing. The failure rate of DIS in this study is higher than for reconstruction with an autologous tendon graft. However, our successfully treated patients had a good clinical and functional outcome based on antero-posterior knee laxity and clinical scores, comparable to patients treated by autograft reconstruction.

Application of Stem Cell Therapy for ACL Graft Regeneration

Graft regeneration after anterior cruciate ligament (ACL) reconstruction surgery is a complex three-stage process, which usually takes a long duration and often results in fibrous scar tissue formation that exerts a detrimental impact on the patients' prognosis. Hence, as a regeneration technique, stem cell transplantation has attracted increasing attention. Several different stem cell types have been utilized in animal experiments, and almost all of these have shown good capacity in improving tendon-bone regeneration. Various differentiation inducers have been widely applied together with stem cells to enhance specific lineage differentiation, such as recombinant gene transfection, growth factors, and biomaterials. Among the various different types of stem cells, bone marrow-derived mesenchymal stem cells (BMSCs) have been investigated the most, while ligament stem progenitor cells (LDSCs) have demonstrated the best potential in generating tendon/ligament lineage cells. In the clinic, 4 relevant completed trials have been reported, but only one trial with BMSCs showed improved outcomes, while 5 relevant trials are still in progress. This review describes the process of ACL graft regeneration after implantation and summarizes the current application of stem cells from bench to bedside, as well as discusses future perspectives in this field.

Risk Factors for Requiring a Revision Anterior Cruciate Ligament Reconstruction: A Case-Control Study

Anterior cruciate ligament (ACL) reconstruction is considered as a successful orthopaedic procedure that attempts to help patients return to their preinjury level of activity. However, some patients may need to undergo revision surgery, and this potentially may be associated with certain surgery-specific or patient risk factors. Therefore, the purpose of this study was to assess the potential role of (1) demographics, (2) family history, (3) graft choice, (4) sport, and (5) mechanism of injury (contact vs. noncontact) in the risk for needing a revision ACL for improved clinical outcomes. All patients who had undergone a primary ACL reconstruction between 2012 and 2016 were identified from at a single institution. About 312 patients who had a mean age of 24 years (range, 9-62 years) and a mean follow-up of 4 years (range, 1-10). Patients were further evaluated to identify those who had a revision. There were 19 patients (6.1%) with a mean age of 22 years (range, 13-38 years) and a mean follow-up of 5 years (range, 1-10) that required a revision reconstruction. Gender ratios (p = 0.56) and mean age (p = 0.44) were similar among the cohorts. Family history of ACL reconstruction had no association with revision risk (p = 0.57). Those with tibialis anterior allografts (37 vs. 4%; p = 0.0001) and hamstring allografts (16 vs. 1%; p = 0.0001) were far more likely to undergo a revision. Bone-tendon-bone (BTB) patella autografts were less likely (26 vs. 73%; p = 0.0001). Sport did not play a role in revision with those injured playing basketball (p = 0.61), football (p = 0.52), lacrosse (p = 0.52), soccer (p = 0.83), and volleyball (p = 0.61). There were a greater percentage of contact injuries that required revision (95 vs. 77%; p = 0.07). Graft selection played a significant role in requiring revision surgery with allografts portending to higher revision rates and BTB patella autografts conferring a lower risk.

Primary Anterior Cruciate Ligament Repair Using Suture Tape Augmentation: A Case Series of 29 Patients With Minimum 2-Year Follow-Up

PURPOSE

To evaluate clinical outcomes and patient-reported outcomes of patients who underwent primary anterior cruciate ligament (ACL) repair using suture tape augmentation.

METHODS

Patients with a proximal tear of the ACL who underwent primary ACL repair with a minimum 2-year follow-up were included. The exclusion criteria included multiligamentous knee injuries, midsubstance tears, tibial avulsion fractures, and distal tears. Demographic characteristics, injury pattern, concomitant injury pattern, and patient-reported outcome measures were recorded. Patients were evaluated at a minimum 2-year follow-up for clinical success, defined as stability not requiring revision ACL reconstruction, and for patient-reported outcome measurements. Failure was defined as the need for revision surgery.

RESULTS

The mean follow-up period was 2.8 ± 0.9 years. Thirty-five patients met the inclusion criteria, with an average age of 32.2 ± 7.2 years, and 2-year follow-up was obtained for 29 of these patients. Revision surgery was required in 2 of the 29 patients (6.9%); successful treatment was achieved in the remaining 93.1%. The Single Assessment Numeric Evaluation score and Knee Injury and Osteoarthritis Outcome Score for the 27 successfully treated patients were recorded, with 70.4% having Single Assessment Numeric Evaluation scores of 80 or greater.

CONCLUSIONS

This case series shows that primary surgical repair of proximal ACL tears using suture tape augmentation results in a low rate of revision surgery.

LEVEL OF EVIDENCE

Level IV, prospective case series.

3T MRI-based anatomy of the anterolateral knee ligament in patients with and without an ACL-rupture: Implications for anatomical anterolateral ligament reconstruction

BACKGROUND

Anterior cruciate ligament (ACL) rupture is often accompanied by an injury to the anterolateral ligament (ALL) of the knee. Detailed knowledge of the ALL attachments in ACL-ruptured patients is essential for an anatomical ALL reconstruction to avoid knee over-constraint and successfully treat the residual rotational instability. The aim of the present study was to investigate the three-dimensional (3D), topographic anatomy of the ALL attachment in both ACL-ruptured and ACL-intact patients using 3 Tesla magnetic resonance imaging (3T MRI).

METHODS

In the present, retrospective case-control study, the magnetic resonance images of 90 knees with an ACL-rupture and 90 matched-controlled subjects, who suffered a non-contact knee injury without an ACL-rupture, were used to create 3D models of the knee. The femoral and tibial ALL footprints were outlined on each model, and their position was measured using an anatomical coordinate system.

RESULTS

The femoral origin of the ALL was located 4.9 ± 2.8 mm posterior and 3.8 ± 2.4 mm proximal to the lateral epicondyle in a non-isometric location in control subjects. In ACL-ruptured patients, it was located in a more posterior and distal, at 6.0 ± 1.9 mm posterior and 2.4 ± 1.7 mm proximal to the lateral epicondyle (p < 0.01), also in a non-isometric location. No difference was found in the tibial ALL insertion between groups.

CONCLUSION

The femoral ALL origin was significantly different in ACL-ruptured patients compared to ACL-intact patients. The recommended femoral tunnel position for the anatomical ALL reconstruction, does not represent the femoral ALL origin in the ACL-ruptured knee.

Anatomic single vs. double-bundle ACL reconstruction: a randomized clinical trial-Part 1: clinical outcomes

PURPOSE

Compare clinical outcomes of anatomic single-bundle (SB) to anatomic double-bundle (DB) anterior cruciate ligament reconstruction (ACLR). It was hypothesized that anatomic DB ACLR would result in better International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) scores and reduced anterior and rotatory laxity compared to SB ACLR.

METHODS

Active individuals between 14 and 50 years of age that presented within 12 months of injury were eligible to participate. Individuals with prior injury or surgery of either knee, greater than a grade 1 concomitant knee ligament injury, or ACL insertion sites less than 14 mm or greater than 18 mm were excluded. Subjects were randomized to undergo SB or DB ACLR with a 10 mm-wide quadriceps tendon autograft harvested with a patellar bone block and were followed for 24 months. The primary outcome measures included the IKDC-SKF and KT-1000 (side to side difference) and pivot shift tests. Other secondary outcomes included measures of sports activity and participation, range of motion (ROM) and re-injury.

RESULTS

Enrollment in the study was suspended due to patellar fractures related to harvest of the patellar bone plug. At that time, 57 subjects had been randomized (29 DB) and two-year follow-up was attained from 51 (89.5%). At 24-month follow-up there were no between-group differences detected for the primary outcomes. Twenty-one (77.8%) DB's and 20 (83.3%) SB's reported returning to pre-injury sports 2 years after surgery (n.s) Three subjects (2 DB's, 5.3% of total) sustained a graft rupture and 5 individuals (4 SB's, 8.8% of total) had a subsequent meniscus injury.

CONCLUSIONS

Due to the early termination of the study, there were no detectable differences in clinical outcome between anatomic SB and DB ACLR when performed with a quadriceps tendon autograft with a bone block in individuals with ACL insertion sites that range from 14 to 18 mm.

LEVEL OF EVIDENCE

Level 2.

Muscular Hernia of the Leg After Anterior Cruciate Ligament Reconstruction with Hamstring Autograft: A Case Report

CASE

A 20-year-old woman presented with symptomatic instability secondary to traumatic anterior cruciate ligament (ACL) rupture. Arthroscopic ACL reconstruction was performed using a 4-strand semitendinosus autograft harvested using a posterior approach. At her 2-month follow-up, a painful mass was palpable, and a hernia of the medial gastrocnemius was confirmed by ultrasound. This was treated with fascial closure. The clinical outcome was excellent at final follow-up.

CONCLUSION

This is the first case reported in the literature of a muscular hernia after an ACL reconstruction using a posterior harvest of the semitendinosus. Surgeons must be aware of this specific complication and how it may be addressed.

TIMELINE OF GAINS IN QUADRICEPS STRENGTH SYMMETRY AND PATIENT-REPORTED FUNCTION EARLY AFTER ACL RECONSTRUCTION

Background

Quadriceps weakness is a predictor of long-term knee function and strength recovery can vary from months to years after anterior cruciate ligament reconstruction (ACLR). However, few studies evaluate quadriceps strength and self-reported function within the first several weeks after ACLR.

Hypothesis/Purpose

To examine changes over time in quadriceps strength symmetry, quadriceps peak torque, and self-reported knee function prior to and at six, 12, and 24 weeks post-ACLR. The hypotheses were 1) quadriceps strength symmetry, bilateral quadriceps peak torque, and patient-reported function would improve over time from pre-ACLR to 24 weeks post-ACLR and 2) significant improvements in patient-reported function, but not strength symmetry, would occur between time points.

Study Design

Prospective, cohort study.

Methods

Thirty participants completed four testing sessions: pre-surgery and six, 12, and 24 weeks post-ACLR. Isometric quadriceps strength testing was performed at six weeks and isokinetic quadriceps strength was measured at all other testing points. Quadriceps index was calculated to evaluate between limb quadriceps strength symmetry. The Knee injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC) were administered at each time point. A repeated-measures analysis of variance evaluated changes over time, with post-hoc comparisons to determine at which time-point significant changes occurred.

Results

Quadriceps strength symmetry, involved limb quadriceps peak torque and all patient-reported outcome scores increased over time (p<0.02). Post-hoc tests showed that neither self-reported outcomes, nor quadriceps index improved between pre-surgery and six-weeks post-ACLR. From six to 12 weeks post-ACLR, scores on IKDC and KOOS Pain, Symptoms, Quality of Life, and Sport subscales improved (p≤0.003). From 12 to 24 weeks post-ACLR, quadriceps strength symmetry, involved limb quadriceps peak torque, KOOS-Symptoms, Quality of Life, and Sport subscales and the IKDC improved (p≤0.01). Uninvolved limb quadriceps peak torque did not change across any time point (p≥0.18).

Conclusion

Patient-reported knee function increased between six and 24 weeks post-ACLR, while increases in involved limb quadriceps strength and quadriceps strength symmetry were not noted until 12-24 weeks post-ACLR.

Level of Evidence

2b, individual cohort study.

Clinical and radiological results after Internal Brace suture versus the all-inside reconstruction technique in anterior cruciate ligament tears 12 to 18 months after index surgery

BACKGROUND

 Anterior cruciate ligament (ACL) injury can lead to reduced function, meniscal lesions, and early joint degeneration. Preservation of a torn ACL using the Internal Brace technique might re-establish normal knee kinematics, avoid donor-site morbidity due to tendon harvesting, and potentially maintain proprioception of the knee.

METHODS

 Fifty subjects were recruited for this study between December 2015 and October 2016. Two groups of individuals who sustained a unilateral ACL rupture were included: those who underwent surgery with preservation of the injured ACL (Internal Brace technique; IB) and those who underwent ACL reconstruction using a hamstring tendon graft (all-inside technique; AI). Subjective self-administered scores were used: the German version of the IKDC Subjective Knee Form (International Knee Documentation Committee), the German version of the WOMAC (Western Ontario and McMaster Universities Arthritis Index), SF-36 (short form), the German version of the KOOS (Knee Osteoarthritis Outcome Score), and the German version of themodified Lysholm Score by Lysholm and Gillquist. Anterior tibial translation was assessed using the KT-1000 Arthrometer (KT-1000 Knee Ligament Arthrometer, MEDmetric Corp., San Diego, CA, USA). Magnetic resonance evaluation was performed in all cases.

RESULTS

 Twenty-three subjects (46 %) were men, and the mean age was 34.7 years. The objective IKDC scores were "normal" in 15 and 14 patients, "nearly normal" in 11 and 7 patients, and "abnormal" in 1 and 2 patients, in the IB and AI groups, respectively. KT-1000 assessment showed a sideto-side difference of more than 3 mm on maximum manual testing in 11 (44 %) and 6 subjects (28.6 %) in the IB and AI groups, respectively. In the postoperative MRI, 20 (74 %) and 22 subjects (96 %) in the IB and AI groups had an intact ACL. Anterior tibial translation was significantly higher in the IB group compared with the AI group in the manual maximum test.

CONCLUSIONS

 Preservation of the native ACL with the Internal Brace primary repair technique can achieve comparable results to ACL reconstruction using Hamstring autografts over a short term. Clinically relevant limitations such as a higher incidence of pathologic laxity, with patients more prone to pivot-shift phenomenon were observed during the study period.

Biological Augmentation of ACL Repair and Reconstruction: Current Status and Future Perspective

Historically, anterior cruciate ligament (ACL) suture repair mostly resulted in failure because of intra-articular hypovascularity and poor intrinsic healing capacity of ACL. ACL reconstruction was therefore deemed the gold standard with a high success rate because of more evolved surgical technique. There are, however, clinical and subclinical disadvantages of reconstruction; low rate in full recovery to sports, donor harvest morbidity, tunnel enlargement, and incomplete microscopic healing of the graft. Recent experimental and clinical studies on biological augmentation of mesenchymal stem cells, platelet-rich plasma, or the other biologic agents with scaffold suggested potential feasibility of positive effects by such bio-therapies for both ACL repair and reconstruction. Biological augmentation of ACL surgery is still in the exploratory stages and more evidence from preclinical and clinical studies is required for implementation in clinical practice.

Anterior cruciate ligament repair versus reconstruction: A kinematic analysis

BACKGROUND

The purpose of this study was to compare the biomechanical properties of an anterior cruciate ligament (ACL) anatomic repair of a true femoral avulsion to an anatomic ACL reconstruction. It was hypothesized that the ACL repair and ACL reconstruction would have comparable biomechanical behavior when compared to the native knee.

METHODS

Ten paired fresh-frozen cadaveric knees (n = 20) were used to investigate knee kinematics when an anterior drawer force, varus, valgus, internal, and external rotational moment were applied at 0, 15, 30, 45, 60, and 90 degrees of flexion. Displacement and rotation were recorded in the following conditions: ACL-intact, ACL-deficient, and ACL-repaired vs reconstructed.

RESULTS

Sectioning of the ACL significantly increased anterior tibial translation (0°, 15°, 30° and 45°) compared to the intact state. The mean anterior displacement difference from intact was lower in the ACL-repaired knees compared to reconstructed knees at 30° and 90°. There were no significant differences between conditions in varus, valgus, internal, or external rotations.

CONCLUSION

ACL repair and ACL reconstruction procedures restored knee anterior tibial translation in matched paired specimens. There were no differences in valgus, varus, internal, or external rotation. Although, ACL-repaired knees (avulsion model) demonstrated less anterior tibial translation when compared to ACL-reconstructed knees, this difference was less than one millimeter. Based on the findings of this study, repair and reconstruction procedures both restored anterior tibial translation in matched-pair specimens. This suggests that the initial functionality of both techniques is similar and that further clinical studies are needed to compare the long-term stability.

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.

A comparative study of anatomical single-bundle anterior cruciate ligament reconstruction using femoral offset aimer versus freehand technique for femoral tunnel preparation

BACKGROUND

ACL reconstruction is one of the commonest orthopaedic procedures performed. There has been a shift in techniques from single bundle to double bundle to anatomic single-bundle reconstruction and also from transtibial to anteromedial method. Anteromedial technique results in more anatomic femoral tunnel with graft positioned at the native insertion site. The tunnel position is crucial for better outcome after ACL reconstruction.

PURPOSE

To compare the femoral tunnel position made by anatomic single-bundle ACL reconstruction using femoral offset aimer device versus freehand drilling with 3D computed tomography.

STUDY DESIGN

A prospective case series involving 60 patients with ACL tear who underwent anteromedial single-bundle ACL reconstruction.

METHODS

Computed tomography scans were performed on 60 knees that underwent single-bundle anteromedial ACL reconstruction with 30 cases involving femoral drilling through aimer device and another 30 cases involving freehand drilling of the tunnel. Three-dimensional models were created, and the data were analysed according to the co-ordinate axes method. Femoral tunnel position was measured in proximal-to-distal and posterior-to-anterior directions. Data from both the groups were compared with each other and already published reference data on anatomical tunnel position.

RESULTS

In the aimer group, the femoral tunnel centre on the medial wall of lateral femoral condyle was located at 35 ± 9% in the posterior-to-anterior direction and at 30 ± 12% in the proximal-to-distal direction. In the freehand group, tunnel was placed at 37 ± 10% in posterior-to-anterior and 28 ± 7% in proximal-to-distal directions. There was no significant difference in tunnel position in both the groups.

CONCLUSION

This study shows there is no significant difference between both the drilling techniques of femoral tunnel, i.e. freehand drilling and drilling with aimer device. Also, it reiterates the efficacy and utility of computed tomography and three-dimensional reconstruction in the analysis of femoral tunnel in ACL reconstruction.

[Dynamic intraligamentary stabilization of acute anterior femoral cruciate ligament rupture : Preliminary and intermediate clinical results]

BACKGROUND

The results of anterior cruciate ligament (ACL) reconstruction demonstrate excellent short and mid-term results; however, long-term follow-up results are compromized by high rates of osteoarthritis. Dynamic intraligamentary stabilization (DIS) focuses on preserving the cruciate ligament. The short and mid-term results of the dynamic ligamentary cruciate ligament suture from a nondevelopmental hospital are presented.

MATERIAL AND METHODS

A total of 73 consecutive patients with an acute rupture of the ACL were included in this prospective study. Patients were surgically treated between July 2014 and October 2017 with DIS within 21 days after ACL rupture. All patients were reviewed before the operation, 60 patients reached a 3‑month follow-up , 51 patients reached a 6‑month follow-up and 38 patients a 12-month follow-up. The perioperative and postoperative complication spectrum was recorded.

RESULTS

The positive results of the developmental clinics were confirmed. The Tegner, Lysholm and International knee documentation Committee (IKDC) scores showed very good results 12 months after surgery. The intraoperative and postoperative complication rates were low at 1.4% and 6.8%, respectively. Postoperative restrictions on movement required re-arthroscopy in 3 patients, 66% of the patients had concomitant damage to the knee joint, which could be treated simultaneously.

CONCLUSION

The dynamic intraligamentary cruciate liament suture (Ligamys) is a successful additional option in the sugical treatment of acute femoral ACL rupture. A high proportion of collateral damage and injuries of the knee joint can be detected and simultaneously treated.

Comparison of Tibial Tuberosity-Trochlear Groove (TT-TG) distances between different anterior cruciate ligament reconstructions: A retrospective clinical and imaging study

BACKGROUND:

Previous studies showed that compared with single-bundle (SB) precedures, double-bundle (DB) anterior cruciate ligament (ACL) reconstruction perform better.

OBJECTIVE:

To make assurance that distance of TT-TG may be altered along with ACL rupture and reconstruction.

METHODS:

Imaging study of 201 patients’s related cases by MRI and CT scans.

RESULTS:

Compared with the intact knee’s overall mean TT-TG value, the mean overall pre/postoperative TT-TG values showed a significant difference. For SB reconstruction, the mean pre/postoperative TT-TG values were 15.67± 2.46 mm and 14.72± 2.48 mm, respectively. Postoperative and intact knee TT-TG values were significantly different (p< 0.001). For DB reconstruction, the pre/postoperative mean TT-TG values were 15.11± 1.99 mm and 13.11± 1.71 mm. Postoperative and intact knee TT-TG values were not significantly different (p= 0.141).

CONCLUSIONS:

The increased TT-TG value from a ruptured ACL was significantly restored after ACL reconstruction. The TT-TG value after SB reconstruction was still obviously larger than that of the intact knee. It showed no significant difference between the postoperative TT-TG of the DB group and intact knees. The original TT-TG values of the knees were much closer to restoration after DB reconstruction.

Anatomical relationship between insertion sites, tunnel placement, and lateral meniscus anterior horn injury during single and double bundle anterior cruciate ligament reconstructions: A comparative macroscopic and histopathological evaluation in cadavers

PURPOSE

The influence of tunnel extension outside the anatomical anterior cruciate ligament (ACL) insertion in single-bundle (SB) or double-bundle (DB) ACL reconstruction is unclear. This study aimed to investigate the anatomical relationship between ACL insertion and tunnel extension in SB and DB ACL reconstruction, and the impact of tibial tunnel extension to the insertion of anterior horn of lateral meniscus in terms of injury.

METHODS

Forty-six paired cadaver knees (mean age, 82.7 ± 10.7 years) were used. Right and left knees were used for SB (10 mm) and DB tunnel reaming (6 mm for the anteromedial and posterolateral bundles). Tibial and femoral tunnels were created to aim at the center of the ACL insertion by arthroscopic visualization. The relationship between tunnel extension and ACL insertion was evaluated macroscopically, and there ratio in two groups were compared by chi-square test. Further, the relative risk for meniscus injury based on tunnel placement was estimated. Coronal section of tibia and parallel section to Blumensaat line in femur were prepared to evaluate the relationship among tunnel position, ACL insertion, and anterior horn of the meniscus histologically.

RESULTS

Tibial tunnel extension out of the ACL insertion was observed macroscopically in 9 (39.1%) knees of the SB group, and 3 (13.0%) of the DB group (p = 0.045). In femoral tunnels, extension out of the ACL insertion was seen in 8 (34.8%) knees of the SB group and 1 (4.3%) of the DB group (p = 0.011). Partial injuries of the lateral meniscus anterior horn (LMAH) were observed in 5 (21.7%) knees of the SB group and 1 (4.3%) knee of the DB group (p = 0.091). The relative risk for LMAH injury was calculated as 5.0 (odds ratio, 6.1). Microscopically, SB tunnels appeared to expand out of ACL insertion, both in the femur and tibia.

CONCLUSIONS

The incidence of tunnel extension out of the ACL insertion in femur and tibia were higher with SB than with DB reconstruction. Furthermore, injury rate of the LMAH in the DB group was lower.

High complication rate following dynamic intraligamentary stabilization for primary repair of the anterior cruciate ligament

PURPOSE

New strategies for dynamic intraligamentary stabilization (DIS) in the primary repair of anterior cruciate ligament (ACL) ruptures are currently under debate. It has been proposed that these might serve as alternative techniques to conventional ACL reconstruction procedures using tendon autografts. The aims of the present investigation were to evaluate the functional results and critically assess the complication rate following primary ACL repair with DIS and to review existing reports of favourable clinical results with the method in relation to knee joint stability and patient satisfaction.

METHODS

Fifty-nine patients received dynamic intraligamentary stabilization a mean of 14 days after ACL rupture. Fifty-seven patients (96.6%, male:female = 37:20; mean age 27.6 years) were available for follow-up examinations including the Tegner activity level, anteroposterior stability in comparison with the uninjured knee, subjective satisfaction, and range of knee motion. Complications after 3 and 12 months were also analyzed. Associated lesions requiring surgical measures were found in 30 patients.

RESULTS

A statistically significant decrease in Tegner activity levels was detected between the preoperative status (median 7) and the 12-month follow-up (median 5). The overall complication rate was 57.9%, including rerupture or non-healing (n = 10, 17.5%), repeat arthroscopy (n = 13, 22.8%) as a result of meniscus tears (n = 2, 15.4%), cyclops syndrome (n = 4, 30.8%) or restricted range of motion (n = 7, 53.8%), arthrofibrosis (n = 3, 5.3%), and implant interference (n = 7, 12.3%). Anteroposterior KT-1000 stability of 3 mm or below was achieved in 29 (50.9%) patients.

CONCLUSIONS

The DIS procedure does not appear to be appropriate for providing predictable results in a young and active cohort of patients following ACL rupture, as it has an unacceptably high complication rate and leads to residual anteroposterior knee joint laxity of 3 mm or more in 28 (49.1%) of cases.

LEVEL OF EVIDENCE

IV (prospective case series).

Biologically Augmented Quadriceps Tendon Autograft With Platelet-Rich Plasma for Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) reconstruction is one of the most common procedures studied in the orthopaedic literature. In this regard, graft preparation is a key factor for successful outcomes. Although current methods to reconstruct the ACL are generally perceived to be successful, recent studies indicate that normal structure and function of the knee are fully restored in less than half of the patients. Therefore, biologically augmenting these scaffolds could provide a potential solution for improving healing times and biomechanical properties of the graft. The purpose of this Technical Note is to describe our preferred technique for an ACL graft preparation (quadriceps tendon) augmented with platelet-rich plasma.

A Narrative Review of Four Different New Techniques in Primary Anterior Cruciate Ligament Repair: "Back to the Future" or Another Trend?

Recently, four different operative techniques, referring to the primary anterior cruciate ligament (ACL) repair, were described. These are the dynamic intraligamentary stabilization (DIS) with Ligamys™, the Bridge-enhanced repair (BEAR), the use of internal brace, and the refixation with suture anchors. The purpose of this study was to assess the already-published, clinical, and pre-clinical results of those techniques. A literature review was conducted and implemented by three independent researchers. Inclusion criteria were clinical or cadaveric or animal studies about patients suffering from ACL rupture, who were treated with one of those four different arthroscopic techniques of primary ACL repair. There were 10 clinical trials dealing with the different techniques of primary ACL repair and 12 cadaveric or animal studies. The majority of the published clinical trials investigated the dynamic intraligamentary stabilization (DIS), while only four studies referred to the three other surgical techniques. Most of the clinical trials suggested that primary ACL repair should be done during the first 14–21 days after a proximal ACL rupture and not later. Further clinical evidence is needed for the techniques of bridge-enhanced ACL repair, internal brace, and suture anchors ACL refixation in order to support the animal and cadaveric biomechanical studies. Till now, the existing clinical trials were not enough to establish the use of those techniques in the ACL-ruptured patients. On the contrary, the Dynamic intraligamentary stabilization with Ligamys™ device demonstrated very promising results in different types of clinical studies.

Comparison of Knee Stability, Strength Deficits, and Functional Score in Primary and Revision Anterior Cruciate Ligament Reconstructed Knees

Comparing to primary surgery, revision ACL reconstruction is more technically demanding and has a higher failure rate. Theoretically, rehabilitation can improve knee function after ACL reconstruction surgery. This study aimed to compare knee stability, strength, and function between primary and revision ACL reconstructed knees. 40 primary and 40 revision ACL reconstruction surgeries were included between April 2013 and May 2016. Patients with revision surgery had a higher anteroposterior translation comparing those with primary reconstruction (median laxity, 2.0 mm vs. 3.0 mm, p = 0.0022). No differences were noted in knee extensor at 60°/sec or 180°/sec (p = 0.308, p = 0.931, respectively) or in flexor muscle strength at 60°/sec or 180°/sec between primary and revision ACL reconstruction knees (p = 0.091, p = 0.343, respectively). There were also no significant differences between functional scores including IKDC score and Lysholm score in primary versus revision surgeries at 12th months after index operation (p = 0.154, p = 0.324, respectively). In conclusion, despite having higher anteroposterior instability, patients with revision ACL reconstruction can have non-inferior outcomes in isokinetic knee strength and function compared to those with primary ACL reconstruction after proper rehabilitation.

Effects of pre-operative knee laxity on clinical outcomes after partial anterior cruciate ligament reconstruction

BACKGROUND

The effects of retaining residual bundles on surgical outcomes has not been observed, so we evaluated the effects of preoperative knee laxity on clinical outcomes after partial anterior cruciate ligament (ACL) reconstruction for partial ACL rupture in this study.

PURPOSE

To evaluate the effects of preoperative knee laxity on clinical outcomes after partial anterior cruciate ligament (ACL) reconstruction for partial ACL rupture.

METHODS

The data of 47 patients, who had partial ACL rupture and underwent partial ACL reconstruction, were retrospectively analyzed. According to preoperative kneelax arthrometer and pivot shift test, the 47 patients were divided into group A (kneelax arthrometer ≤5mm and pivot shift test <II grade, n=26) and group B (kneelax arthrometer >5mm and/or pivot shift test ≥II grade, n=21). The minimum follow-up duration lasted 2 years. The clinical outcomes were evaluated using IKDC (International Knee Documentation Committee) scoring systems, Lysholm knee scoring scale, Tegner activity rating, Lachman test, Pivot shift test and the kneelax arthrometer.

RESULTS

The function and stability examinations for the affected knee joint were significantly improved in both groups after partial ACL reconstruction as compared with preoperative ones (all P<0.01). There were no significant differences in the post-operative Lysholm and Tegner scores, Lachman and Pivot shift test results between both groups (all P>0.05). However, there were significant differences between the two groups in terms of the post-operative IKDC scoring system and kneelax arthrometer examination result (all P<0.05).

CONCLUSIONS

In the patients with partial ACL rupture, the mechanical strength of the remnant ligament has significant influence on the therapeutic effects of partial reconstruction. The patients with kneelax arthrometer >5mm and/or pivot shift test ≥II grade still have anterior instability in the affected knee after partial reconstruction.

Preoperative PROMIS Scores Predict Postoperative Outcomes After Primary ACL Reconstruction

Background:

PROMIS (Patient-Reported Outcomes Measurement Information System) scores in patients undergoing anterior cruciate ligament (ACL) reconstruction have not been fully described in the literature to date. The ability of preoperative patient-reported outcome scores to directly predict postoperative outcomes in patients who undergo primary ACL reconstruction is unknown.

Hypothesis:

Postoperative PROMIS physical function (PF), pain interference (PI), and depression (D) scores in patients who undergo ACL reconstruction will show improvement when compared with preoperative scores. Additionally, preoperative PROMIS PF, PI, and D scores will predict which patients will not achieve a minimal clinically important difference (MCID) postoperatively.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 233 patients who underwent primary ACL reconstruction between 2015 and 2016 and had completed PROMIS measures both preoperatively (within 60 days of surgery) and postoperatively (100-240 days after surgery) were included in this study. PROMIS PF, PI, and D scores were compared. Accuracy analyses were performed to determine whether preoperative PROMIS scores from each domain could predict postoperative achievement of MCID in the same domain. Cutoff scores were then calculated.

Results:

PROMIS PF, PI, and D scores all showed a significant improvement after ACL reconstruction (all P < .001). Preoperative scores from all 3 PROMIS domains showed a strong ability to predict clinically meaningful improvement, as defined by MCID, with areas under the receiver operating characteristic curve from 0.72 to 0.84. Optimal cutoffs for preoperative PROMIS scores showed that patients with a PF score of <42.5, PI score of >56.2, or D score of >44.8 were more likely to achieve MCID.

Conclusion:

PROMIS PF, PI, and D scores improved significantly in patients who underwent primary ACL reconstruction. Preoperative PROMIS PF, PI, and D scores were highly predictive of outcome in the early postoperative period. The reported cutoff scores showed high probability in predicting which patients would and would not achieve a clinically meaningful improvement.

Self-reported functional recovery after reconstruction versus repair in acute anterior cruciate ligament rupture (ROTOR): a randomized controlled clinical trial

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction is today's surgical gold standard for ACL rupture. Although it provides satisfactory results, not all patients return to their previous activity level and moreover, early posttraumatic osteoarthritis is not prevented. As such, a renewed interest has emerged in ACL suture repair combined with dynamic augmentation. Compared to ACL reconstruction, the hypothesized advantages of ACL suture repair are earlier return to sports, reduction of early posttraumatic osteoarthritis and preservation of the patient's native ACL tissue and proprioceptive envelope of the knee. In recent literature, ACL suture repair combined with dynamic augmentation tends to be at least equally effective compared to ACL reconstruction, but no randomized comparative study has yet been conducted.

METHODS/DESIGN

This study is a prospective, stratified, block randomized controlled trial. Forty-eight patients with an ACL rupture will be assigned to either a suture repair group with dynamic augmentation and microfracture of the femoral notch, or an ACL reconstruction group with autologous semitendinosis graft and all-inside technique. The primary objective is to investigate the hypothesis that suture repair of a ruptured ACL results in at least equal effectiveness compared with an ACL reconstruction in terms of patient self-reported outcomes (IKDC 2000 subjective scale) 1 year postoperatively. Secondary objectives are to evaluate patient self-reported outcomes (IKDC 2000, KOOS, Tegner, VAS), re-rupture rate, rehabilitation time required for return to daily and sports activities, achieved levels of sports activity, clinimetrics (Rolimeter, LSI, Isoforce) and development of osteoarthritis, at short term (6 weeks, 3, 6 and 9 months and 1 year), midterm (2 and 5 years) and long term (10 years) postoperatively.

DISCUSSION

A renewed interest has emerged in ACL suture repair combined with dynamic augmentation in the treatment of ACL rupture. Recent cohort studies show good short- and midterm results for this technique. This randomized controlled trial has been designed to compare the outcome of suture repair of a ruptured ACL, combined with DIS as well as microfracture of the femoral notch, with ACL reconstruction using autologous semitendinosus.

TRIAL REGISTRATION

Clinical Trials Register NCT02310854 (retrospectively registered on December 1st, 2014).

In situ force in the anterior cruciate ligament, the lateral collateral ligament, and the anterolateral capsule complex during a simulated pivot shift test

The role of the anterolateral capsule complex in knee rotatory stability remains controversial. Therefore, the objective of this study was to determine the in situ forces in the anterior cruciate ligament (ACL), the anterolateral capsule, the lateral collateral ligament (LCL), and the forces transmitted between each region of the anterolateral capsule in response to a simulated pivot shift test. A robotic testing system applied a simulated pivot shift test continuously from full extension to 90° of flexion to intact cadaveric knees (n = 7). To determine the magnitude of the in situ forces, kinematics of the intact knee were replayed in position control mode after the following procedures were performed: (i) ACL transection; (ii) capsule separation; (iii) anterolateral capsule transection; and (iii) LCL transection. A repeated measures ANOVA was performed to compare in situ forces between each knee state (*p < 0.05). The in situ force in the ACL was significantly greater than the forces transmitted between each region of the anterolateral capsule at 5° and 15° of flexion but significantly lower at 60°, 75°, and 90° of flexion. This study demonstrated that the ACL is the primary rotatory stabilizer at low flexion angles during a simulated pivot shift test in the intact knee, but the anterolateral capsule plays an important secondary role at flexion angles greater than 60°. Furthermore, the contribution of the "anterolateral ligament" to rotatory knee stability in this study was negligible during a simulated pivot shift test. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:847-853, 2018.

Proprioceptive Changes in Bilateral Knee Joints Following Unilateral Anterior Cruciate Ligament Injury in Cynomolgus Monkeys

BACKGROUND The anterior cruciate ligament (ACL) is one of the most important structures maintaining stability of knee joints, and the proprioception of the ACL plays a key role in it. If the ACL is injured in the unilateral knee joint, it changes nerve electrophysiology, morphology, and quantity of the proprioceptors in the bilateral ACL. The aim of this study was to explore the proprioceptive changes in the bilateral knee joints following unilateral ACL injury, and to provide a theoretical foundation and ideas for clinical treatment. MATERIAL AND METHODS Nine normal cynomolgus monkeys were chosen and used to developed a model of unilateral ACL injury, and 3 monkeys without modeling were used as blank control. At the 4th, 8th, and 12th weeks, the changes in ACL nerves were inspected using electrophysiology [somatosensory evoked potentials (SEPs) and motor nerve conduction velocity (MCV)], and the changes of morphology and quantity of the proprioceptors in ACL were observed and measured under gold chloride staining. RESULTS On the injured and contralateral knee joints, the incubations were extended and the amplitudes were decreased over time. In addition, with the extension of time, the total number of proprioceptors in the ACL decreased, and the variable number of proprioceptors in the ACL increased. CONCLUSIONS ACL injury leads to attenuation of proprioception on the injured side, and also leads to the attenuation of proprioception on the contralateral side, and there is a tendency could get worse over time.

A Prospective Evaluation of Femoral Tunnel Placement for Anatomic Anterior Cruciate Ligament Reconstruction Using 3-Dimensional Magnetic Resonance Imaging

BACKGROUND

The recent emphasis on anatomic reconstruction of the anterior cruciate ligament (ACL) is well supported by clinical and biomechanical research. Unfortunately, the location of the native femoral footprint can be difficult to see at the time of surgery, and the accuracy of current techniques to perform anatomic reconstruction is unclear.

PURPOSE

To use 3-dimensional magnetic resonance imaging (3D MRI) to prospectively evaluate patients with torn ACLs before and after reconstruction and thereby assess the accuracy of graft position on the femoral condyle.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Forty-one patients with unilateral ACL tears were recruited into the study. Each patient underwent 3D MRI of both the injured and uninjured knees before surgery. The contralateral (uninjured) knee was used to define the patient's native footprint. Patients then underwent ACL reconstruction, and the injured knee underwent reimaging after surgery. The location and percentage overlap of the reconstructed femoral footprint were compared with the patient's native footprint.

RESULTS

The center of the native ACL femoral footprint was a mean 12.0 ± 2.6 mm distal and 9.3 ± 2.2 mm anterior to the apex of the deep cartilage. The position of the reconstructed graft was significantly different, with a mean distance of 10.8 ± 2.2 mm distal ( P = .02) and 8.0 ± 2.3 mm anterior ( P = .01). The mean distance between the center of the graft and the center of the native ACL femoral footprint (error distance) was 3.6 ± 2.6 mm. Comparing error distances among the 4 surgeons demonstrated no significant difference ( P = .10). On average, 67% of the graft overlapped within the native ACL femoral footprint.

CONCLUSION

Despite contemporary techniques and a concerted effort to perform anatomic ACL reconstruction by 4 experienced sports orthopaedic surgeons, the position of the femoral footprint was significantly different between the native and reconstructed ACLs. Furthermore, each surgeon used a different technique, but all had comparable errors in their tunnel placements.

Influence of knee flexion angle and transverse drill angle on creation of femoral tunnels in double-bundle anterior cruciate ligament reconstruction using the transportal technique: Three-dimensional computed tomography simulation analysis

BACKGROUND

The purpose of this study was to find appropriate flexion angle and transverse drill angle for optimal femoral tunnels of anteromedial (AM) bundle and posterolateral (PL) bundle in double-bundle ACL reconstruction using transportal technique.

METHODS

Thirty three-dimensional knee models were reconstructed. Knee flexion angles were altered from 100° to 130° at intervals of 10°. Maximum transverse drill angle (MTA), MTA minus 10° and 20° were set up. Twelve different tunnels were determined by four flexion angles and three transverse drill angles for each bundle. Tunnel length, wall breakage, inter-tunnel communication and graft-bending angle were assessed.

RESULTS

Mean tunnel length of AM bundle was >30mm at 120° and 130° of flexion in all transverse drill angles. Mean tunnel length of PL bundle was >30mm during every condition. There were ≥1 cases of wall breakage except at 120° and 130° of flexion with MTA for AM bundle. There was no case of wall breakage for PL bundle. Considering inter-tunnel gap of >2mm without communication and obtuse graft-bending angle, 120° of flexion and MTA could be recommended as optimal condition for femoral tunnels of AM and PL bundles.

CONCLUSION

Flexion angle and transverse drill angle had combined effect on femoral tunnel in double-bundle ACL reconstruction using transportal technique. Achieving flexion angle of 120° and transverse drill angle close to the medial femoral condyle could be recommended as optimal condition for femoral tunnels of AM and PL bundles to avoid insufficient tunnel length, wall breakage, inter-tunnel communication and acute graft-bending angle.

Complications following harvesting of patellar tendon or hamstring tendon grafts for anterior cruciate ligament reconstruction: Systematic review of literature

Anterior cruciate ligament (ACL) reconstruction can be performed with an autograft, which is most often harvested from the patient's hamstring tendon (HT) or patellar tendon (PT). However, autograft harvesting leads to morbidity that is by no means insignificant. A systematic review of literature was performed to define the incidence of complications related to graft harvesting and the methods to prevent these complications. In March 2017, a systemic review of literature was performed using the keywords"harvesting", "harvest", "morbidity", "complication", "cruciate ligament". No time limit was applied. The studies had to be written in French or English with their abstract available online. This initial search based on the title and abstract identified 133 articles. Two independent observers analyzed each article entirely, including the references. In all, 36 articles were retained. The main complication of HT harvesting was sensory deficit because of damage to the infrapatellar branches of the saphenous nerve. This complication occurred in 39.7% to 88% of patients. This risk can be reduced by using a horizontal or oblique incision. The main complication following PT harvesting is anterior knee pain, reported in up to 46% of patients. There are substantial numbers of short-, medium- and long-term complications related to the harvesting of the two main ACL autografts. Effective means of prevention exist to reduce the risk of these complications.

LEVEL OF EVIDENCE

II Systematic review of literature.