Long-term Outcomes of Primary Repair of the Anterior Cruciate Ligament Combined With Biologic Healing Augmentation to Treat Incomplete Tears

Anterior Cruciate Ligament Repair-Here to Stay or History Repeating Itself?

Anterior cruciate ligament (ACL) injuries continue to be a prevalent concern among athletes and individuals with an active lifestyle. Traditionally, the standard of care for ACL tears has involved surgical reconstruction using autograft or allograft. This article aims to provide an overview of the evolving landscape of primary ACL repair, examining the current evidence, surgical techniques, patient selection criteria, outcomes, and potential future directions in this field.

Clinical Results of Primary Repair Versus Reconstruction of the Anterior Cruciate Ligament: A Systematic Review and Meta-analysis of Contemporary Trials

Background

Primary anterior cruciate ligament (ACL) repair has gained renewed interest in select centers for patients with proximal or midsubstance ACL tears. Therefore, it is important to reassess contemporary clinical outcomes of ACL repair to determine whether a clinical benefit exists over the gold standard of ACL reconstruction (ACLR).

Purpose

To (1) perform a meta-analysis of comparative trials to determine whether differences in clinical outcomes and adverse events exist between ACL repair versus ACLR and (2) synthesize the midterm outcomes of available trials.

Study Design

Systematic review; Level of evidence, 3.

Methods

The PubMed, OVID/Medline, and Cochrane databases were queried in August 2023 for prospective and retrospective clinical trials comparing ACL repair and ACLR. Data pertaining to tear location, surgical technique, adverse events, and clinical outcome measures were recorded. DerSimonian-Laird random-effects models were constructed to quantitatively evaluate the association between ACL repair/ACLR, adverse events, and clinical outcomes. A subanalysis of minimum 5-year outcomes was performed.

Results

Twelve studies (893 patients; 464 ACLR and 429 ACL repair) were included. Random-effects models demonstrated a higher relative risk (RR) of recurrent instability/clinical failure (RR = 1.64; 95% confidence interval [CI], 1.04-2.57; P = .032), revision ACLR (RR = 1.63; 95% CI, 1.03-2.59; P = .039), and hardware removal (RR = 4.94; 95% CI, 2.10-11.61; P = .0003) in patients who underwent primary ACL repair versus ACLR. The RR of reoperations and complications (knee-related) were not significantly different between groups. No significant differences were observed when comparing patient-reported outcome scores. In studies with minimum 5-year outcomes, no significant differences in adverse events or Lysholm scores were observed.

Conclusion

In contemporary comparative trials of ACL repair versus ACLR, the RR of clinical failure, revision surgery due to ACL rerupture, and hardware removal was greater for primary ACL repair compared with ACLR. There were no observed differences in patient-reported outcome scores, reoperations, or knee-related complications between approaches. In the limited literature reporting on minimum 5-year outcomes, significant differences in adverse events or the International Knee Documentation Committee score were not observed.

The potential of posterior cruciate ligament buckling phenomenon as a sign for partial anterior cruciate ligament tears

INTRODUCTION

Diagnosis of a partial tear of the anterior cruciate ligament (ACL) can be challenging with physical examination and imaging techniques. Although magnetic resonance imaging (MRI) has high sensitivity and specificity for diagnosing complete ACL tears, its effectiveness may be limited when it is used to diagnose for partial tears. The hypothesis of the present study is that the posterior cruciate ligament (PCL) buckling phenomenon, which is a secondary sign of complete ACL tears on MRI, may be a useful method for diagnosing partial ACL tears.

MATERIALS AND METHODS

The data of 239 patients who underwent knee arthroscopy in a single institution between 2016 and 2022 were analyzed retrospectively. Patients were divided into three groups based on the condition of their ligaments: partial tears, complete tears and intact ligaments. To evaluate the buckling phenomenon on sagittal T2-weighted MRI, measurements of the posterior cruciate ligament angle (PCLA) and the posterior cruciate ligament-posterior cortex angle (PCL-PCA) were conducted in each group. Subsequently, the ability of these two measurement methods to distinguish partial tears from the other groups was assessed.

RESULTS

Both methods provided significantly different results in all three groups. Partial tears could be distinguished from intact ligaments with 86.8% sensitivity, 89.9% specificity when PCLA < 123.13° and 94.5% sensitivity, 93.2% specificity when PCL-PCA < 23.77°. Partial tears could be distinguished from complete tears with 79.5% sensitivity, 78.4% specificity when PCLA > 113.88° and with 86.1% sensitivity, 85.3% specificity when PCL-PCA > 16.39°.

CONCLUSION

The main finding of the present study is that the PCLA and PCL-PCA methods are useful on MRI for diagnosing partial ACL tears. PCLA value between 113°-123° and PCL-PCA value between 16°-24° could indicate a partial ACL tear. With these methods, it is possible to distinguish partial tears from healthy knees and reduce missed diagnoses. In addition, the differentiation of partial and complete tears by these methods may prevent unnecessary surgical interventions.

LEVEL OF EVIDENCE

Level III.

The healing effect of the all inside technique is superior to the traditional technique in the reconstruction of the anterior cruciate ligament

Our main objective was to examine the curative effect of all inside technique and traditional technique in anterior cruciate ligament (ACL) reconstruction. In our retrospective study at the First People's Hospital of Jiashan County, we analyzed 88 participants with ACL injuries (50 males, 38 females, average age 27 years). They were randomly divided into two groups: traditional ACL reconstruction (42 participants) and all inside ACL reconstruction (46 participants). We measured and recorded the Visual Analog Scores (VAS), International Knee Documentation Committee (IKDC), Lysholm scores, operation time, graft diameter and length between the traditional technique group and all inside technique group. There were statistically significant differences in the Lysholm scores and IKDC scores between traditional and all inside technique groups. The all inside technique showed a higher efficacy and effective post-operative recovery with minimal pain and recurrent injuries. Our findings showed that the differences in gender, age, side of injury and operation time were not significant (p> 0.05). Follow-up was conducted at 6 months and 12 months post operations (mean, 7.5 ± 1.1 months). All inside technique minimizing tissue disruption, optimizing graft placement and facilitating early recovery have a significant impact on patient outcomes.

Primary anterior cruciate ligament repair: Current concepts

The renewed interest in ACL repair over the last two decades stems from advances in modern arthroscopic techniques and clinical studies that have provided evidence that the ACL can reliably heal, and patients can return to sport at a comparable rate to ACL reconstruction patients. The ability to maintain and utilize native ACL tissue, with proprioceptive capabilities, and the smaller drill tunnels needed to repair an ACL leads to an overall less invasive procedure and improved early rehabilitation. Additionally, repair avoids a variety of comorbidities associated with autograft harvest. This current concept review details modern techniques of ACL repair and their current studies, a review on the use of biologic enhancement in ACL repair, and other considerations to appropriately integrate ACL repair into the sports medicine orthopaedic surgeon's practice.

Cruciate and Collateral Ligaments: 2-Dimensional and 3-Dimensional MR Imaging-Aid to Knee Preservation Surgery

Being a major load-bearing and dynamic functional joint of the body, the knee joint is prone to injuries to the menisci and ligaments. Injury to one or more of these structures leads to accelerated or premature osteoarthritis and chronic debilitation. The estimated cost of these injuries in terms of diagnosis, treatment, rehabilitation, and person-hours lost amounts to over a billion dollars annually. Understanding the relevant anatomy of knee cruciate and collateral ligaments, their biomechanical functional role, and imaging considerations are essential to assist multi-disciplinary communications and timely patient treatments for improved management. MRI is considered the gold standard over other imaging modalities like X-ray, ultrasound (US), and Computed Tomography (CT) for diagnosing and assessing such injuries. High-resolution 2D and 3D MRI are considerably helpful in planning for knee preservation surgery, and this article reviews the role of such imaging as a valuable aid to knee preservation surgery in pre-and post-operative states. Relevant arthroscopy correlations have been illustrated.

Influences of Partial Anterior Cruciate Ligament Injury On Anterior Cruciate Ligament Tensional Force and Kinematic Stability During Walking

Injuries in the anterior cruciate ligament (ACL), including partial tear and lengthening of the ACL, change the dynamic function of the knee. However, there is a lack of information on the effect of ACL partial tear on knee kinematics during walking. This study aimed to investigate the effects of different levels of ACL injuries on the knee stability and ACL tensional force to identify the critical injury level. Motion data of five normal subjects were acquired along with the ground reaction force. A knee model with 14 ligaments was developed using cadaveric specimen data. The initial length and stiffness of the ACL were changed to develop ACL-injured knee models. Musculoskeletal simulations of the knee models were performed using the measured gait data. The average tibial anterior translation increased significantly by 2.6 ± 0.7 mm when the ACL stiffness decreased to 25% of its original stiffness. The average tibial anterior translation increased significantly by 2.6 ± 0.3 mm at an increase in initial length of 10%. The knee with partial ACL tear had a non-linear decrease in ACL forces owing to the increase in the level of ACL injury, while the knee with ACL lengthening had linear decreased ACL forces. The partial tear of the ACL caused translational instability, while the complete tear caused both rotational and translational instabilities during the musculoskeletal walking simulation. This study presents the effects of partial ACL injuries on joint kinematics and ACL tensional force during the dynamic motion of walking.

Mucoid degeneration of the anterior cruciate ligament: can platelet-rich plasma combined with reductionplasty provide better results?

Introduction: Mucoid degeneration of the anterior cruciate ligament (ACL) is commonly treated with arthroscopic debridement of the ACL. But many studies have reported the weakening and laxity of ACL postoperatively and on follow-up. Platelet-rich plasma (PRP) is known to influence musculoskeletal healing through multiple growth factors. Methodology: Five patients who were diagnosed as a case of mucoid degeneration of the ACL based on MRI, over a period of 1 year (December 2018-2019), were included in the study. Autologous PRP, prepared by double spin protocol, was injected into the remaining ACL after partial debridement was done. Results: Visual analogue scale and Lysholm scores improved compared with preoperative scores, along with strength (anterior drawer test and Lachman test). Conclusion: PRP can be used to improve the healing and strength of a weakened ACL after partial debridement, but further research is needed to demonstrate its efficacy.

Differential regional perfusion of the human anterior cruciate ligament: quantitative magnetic resonance imaging assessment

Purpose

Surgical reconstruction is the current standard for ACL rupture treatment in active individuals. Recently, there is renewed interest in primary repair of proximal ACL tears. Despite this, ACL biology and healing potential are currently not well understood. Vascularity is paramount in ACL healing; however, previous ACL vascularity studies have been limited to qualitative histological and dissection-based techniques. The study objective was to use contrast-enhanced quantitative-MRI to compare relative perfusion of proximal, middle, and distal thirds of the in situ ACL. We hypothesized perfusion would be greatest in the proximal third.

Methods

Fourteen cadaveric knees were studied (8 females, 6 males), age 25–61 years. Superficial femoral, anterior tibial, and posterior tibial arteries were cannulated; without intraarticular dissection. Contrast-enhanced quantitative-MRI was performed using a previously established protocol. ACL regions corresponding to proximal, middle, and distal thirds were identified on sagittal-oblique pre-contrast images. Signal enhancement (normalized to tibial plateau cartilage) was quantified to represent regional perfusion as a percentage of total ACL perfusion. Comparative statistics were computed using repeated measures ANOVA, and pairwise comparisons performed using the Bonferroni method.

Results

Relative perfusion to proximal, middle, and distal ACL zones were 56.0% ±17.4%, 28.2% ±14.6%, and 15.8% ±16.3%, respectively (p = 0.002). Relative perfusion to the proximal third was significantly greater than middle (p = 0.007) and distal (p = 0.001). No statistically relevant difference in relative perfusion was found to middle and distal thirds (p = 0.281). Post-hoc subgroup analysis demonstrated greater proximal perfusion in males (66.9% ± 17.3%) than females (47.8% ± 13.0%), p = 0.036.

Conclusion

Using quantitative-MRI, in situ adult ACL demonstrated greatest relative perfusion to the proximal third, nearly 2 times greater than the middle third and 3 times greater than the distal third. Knowledge of differential ACL vascular supply is important for understanding pathogenesis of ACL injury and the process of biological healing following various forms of surgical treatment.

Biological enhancement methods may be a viable option for ACL arthroscopic primary repair - A systematic review

BACKGROUND

Bioactive factors combined with advanced anterior cruciate ligament (ACL) primary repair technology have been used to treat ACL repairs. The current review was conducted to identify whether biological enhancement could enable superior clinical outcome, including side-to-side difference, failure rate, reoperation rate and subjective scores.

HYPOTHESIS

The implementation of ACL primary repair with biological enhancement will provide better clinical outcomes in terms of side-to-side differences, failure rate, reoperation rate and subjective scores than ACL primary repair alone.

MATERIALS AND METHODS

A systematic literature review was performed following PRISMA guidelines by searching all studies reporting outcomes of arthroscopic primary repair with or without biological augmentation published until April 19, 2020, in Medline, PubMed, Embase and the Cochrane Library. Primary metrics were side-to-side differences, failure rate and reoperation rate, as well as measurements of patient-reported outcomes at the last follow-up.

RESULTS

A total of 20 studies were finally included in this work, of which 3 were Grade I (15%), 3 studies were Grade III (15%), and 14 studies were Grade IV (70%) in terms of the level of evidence. There were 729 patients with a mean age of 30 (range: 8-68) years, and the mean follow-up period of which was 38 (range: 3-122) months. At the final follow-up, the postoperative side-to-side differences (the proportion of patients with a side-to-side difference less than 3mm) and patient-report outcomes were significantly better in the biological enhancement group. Nevertheless, there were no significant differences between the two groups in the rate of surgical failure, the rate of revision, or the positive Lachman test or pivot shift test.

CONCLUSION

Biologically enhanced arthroscopic ACL primary repair was superior to ACL primary repair alone in terms of postoperative side-to-side differences (proportion of patients with a side-to-side difference less than 3mm) and patient-reported outcomes. Thus, biologically enhanced arthroscopic ACL primary repair can be preferentially recommended over ACL arthroscopic primary repair alone.

LEVEL OF EVIDENCE

IV, systematic review.

Canine ACL rupture: a spontaneous large animal model of human ACL rupture

Background

Anterior cruciate ligament (ACL) rupture in humans is a common condition associated with knee pain, joint instability, and secondary osteoarthritis (OA). Surgical treatment with an intraarticular graft provides reasonable outcomes at mid and long-term follow-up. Non-modifiable and modifiable factors influence risk of ACL rupture. The etiology, mechanobiology, causal biomechanics, and causal molecular pathways are not fully understood. The dog model has shared features of ACL rupture that make it a valuable spontaneous preclinical animal model. In this article, we review shared and contrasting features of ACL rupture in the two species and present information supporting spontaneous canine ACL rupture as a potentially useful preclinical model of human ACL rupture with a very large subject population.

Results

ACL rupture is more common in dogs than in humans and is diagnosed and treated using similar approaches to that of human patients. Development of OA occurs in both species, but progression is more rapid in the dog, and is often present at diagnosis. Use of client-owned dogs for ACL research could reveal impactful molecular pathways, underlying causal genetic variants, biomechanical effects of specific treatments, and opportunities to discover new treatment and prevention targets. Knowledge of the genetic contribution to ACL rupture is more advanced in dogs than in humans. In dogs, ACL rupture has a polygenetic architecture with moderate heritability. Heritability of human ACL rupture has not been estimated.

Conclusion

This article highlights areas of One Health research that are particularly relevant to future studies using the spontaneous canine ACL rupture model that could fill gaps in current knowledge.

Biologic agents to optimize outcomes following ACL repair and reconstruction: A systematic review of clinical evidence

Treatment options for anterior cruciate ligament (ACL) injuries have greatly developed over the past decades. Although reconstruction surgery is a concrete reality, stimulation of ACL healing through biological techniques could represent a revolutionary conservative approach. The use of biologic products, such as platelet-rich plasma (PRP) or mesenchymal stem cells (MSCs), to treat partial ruptures or to enhance ligamentization after reconstruction, could thoroughly improve clinical outcomes. The aim of the present paper is to systematically review the available literature on this topic, to (i) describe the current state of the art in available biologic techniques; (ii) clarify the outcomes of their application; (iii) identify areas needing further investigation and possible future development. A systematic review of the literature on the use of biologically active agents (PRP and MSCs) to enhance outcomes of ACL surgery was performed: 31 studies were included. Based on the ACL injury pattern, 6 papers investigated biologic agents in ACL partial tears whereas 25 papers in ACL reconstruction. Sixteen of twenty-five studies dealing with ACL reconstruction were randomized controlled trials, whereas only case series are available for partial ACL tears. Current evidence is still lacking sound data to support the use of biological agents: no clinical superiority has been described when using PRP in ACL reconstruction. Concerning ACL healing in partial tears, the application of PRP has led to encouraging outcomes, but these findings should be confirmed by appropriately designed RCTs.

Cell-based treatment options facilitate regeneration of cartilage, ligaments and meniscus in demanding conditions of the knee by a whole joint approach

PURPOSE

This article provides an update on the current therapeutic options for cell-based regenerative treatment of the knee with a critical review of the present literature including a future perspective on the use of regenerative cell-based approaches. Special emphasis has been given on the requirement of a whole joint approach with treatment of comorbidities with aim of knee cartilage restoration, particularly in demanding conditions like early osteoarthritis.

METHODS

This narrative review evaluates recent clinical data and published research articles on cell-based regenerative treatment options for cartilage and other structures around the knee RESULTS: Cell-based regenerative therapies for cartilage repair have become standard practice for the treatment of focal, traumatic chondral defects of the knee. Specifically, matrix-assisted autologous chondrocyte transplantation (MACT) shows satisfactory long-term results regarding radiological, histological and clinical outcome for treatment of large cartilage defects. Data show that regenerative treatment of the knee requires a whole joint approach by addressing all comorbidities including axis deviation, instability or meniscus pathologies. Further development of novel biomaterials and the discovery of alternative cell sources may facilitate the process of cell-based regenerative therapies for all knee structures becoming the gold standard in the future.

CONCLUSION

Overall, cell-based regenerative cartilage therapy of the knee has shown tremendous development over the last years and has become the standard of care for large and isolated chondral defects. It has shown success in the treatment of traumatic, osteochondral defects but also for degenerative cartilage lesions in the demanding condition of early OA. Future developments and alternative cell sources may help to facilitate cell-based regenerative treatment for all different structures around the knee by a whole joint approach.

LEVEL OF EVIDENCE

IV.

Current and future of anterior cruciate ligament reconstruction techniques

In recent years, anterior cruciate ligament (ACL) reconstruction has generally yielded favorable outcomes. However, ACL reconstruction has not provided satisfactory results in terms of the rate of returning to sports and prevention of osteoarthritis (OA) progression. In this paper, we outline current techniques for ACL reconstruction such as graft materials, double-bundle or single-bundle reconstruction, femoral tunnel drilling, all-inside technique, graft fixation, preservation of remnant, anterolateral ligament reconstruction, ACL repair, revision surgery, treatment for ACL injury with OA and problems, and discuss expected future trends. To enable many more orthopedic surgeons to achieve excellent ACL reconstruction outcomes with less invasive surgery, further studies aimed at improving surgical techniques are warranted. Further development of biological augmentation and robotic surgery technologies for ACL reconstruction is also required.

Arthroscopic Primary Repair for Partial Proximal Anterior Cruciate Ligament Tear in Military Personnel

OBJECTIVE

To evaluate the short-term clinical outcomes of arthroscopic primary repair for partial proximal anterior cruciate ligament (ACL) tear in a young, active duty military population.

DESIGN

Retrospective cohort study.

SETTING

A national tertiary-level medical and academic institution.

PATIENTS

Nineteen active duty military patients with partial proximal ACL tears and excellent tissue quality were included and 18 were finally analyzed.

INTERVENTIONS

All patients underwent arthroscopic primary repair using a suture anchor technique between March 2014 and June 2016.

MAIN OUTCOME MEASURES

Clinical outcomes were evaluated using anterior drawer test (ADT), Lachman test, pivot shift test, 3-km run test, 10 m × 5 shuttle run test, physical readiness test (PRT) score, Tegner activity score, Lysholm score, modified Cincinnati score, International Knee Documentation Committee (IKDC) subjective score, and magnetic resonance imaging.

RESULTS

At final follow-up, 17 patients had negative ADT, Lachman, and pivot shift examination findings, and 1 patient had a 1+ ADT, negative Lachman, and pivot shift result. Mean 3-km run time at final follow-up was not statistically different from that preinjury (12:55 vs 12:39, P = 0.071), nor were the 10 m × 5 shuttle run time (23.4 vs 22.9, P = 0.235), PRT score (82.5 vs 85.1, P = 0.086), and Tegner activity score (7.8 vs 7.9, P = 0.083). Mean Lysholm score at final follow-up was significantly improved compared with that preoperative (93.1 vs 70.7, P < 0.001), so were the modified Cincinnati score (90.4 vs 58.6, P < 0.001) and IKDC subjective score (88.3 vs 67.4, P < 0.001).

CONCLUSIONS

Arthroscopic primary repair can achieve short-term clinical success in high-demand military patients with partial proximal ACL tears and excellent tissue quality.

The Comparison of Clinical Result between Primary Repair of the Anterior Cruciate Ligament with Additional Internal Bracing and Anatomic Single Bundle Reconstruction-A Retrospective Study

BACKGROUND

The current standard of treatment of anterior cruciate ligament (ACL) is reconstruction (ACLR). This technique has some disadvantages: poor proprioception, donor site morbidity and the inability to restore joint kinematics. ACL repair could be an alternative treatment. The purpose of the study was to compare the stability and the function after ACL primary repair versus single-bundle ACLR.

METHODS

In a retrospective study, 12 patients underwent primary ACL repair with internal bracing, 15 patients underwent standard ACLR. Follow-up examinations were evaluated at up to 2 years postoperatively. One patient in the ACL repair group was lost to follow-up due to re-rupture. The absolute value of anterior tibial translation (ATT) and the side-to-side difference in the same patient (ΔATT) were evaluated using the GNRB arthrometer. The Lysholm knee scoring was obtained. Re-ruptures and other complications were recorded.

RESULTS

Anterior tibial translation (ATT) was significantly decreased in the ACL repair group compared with the ACLR group (5.31 mm vs. 7.18 mm, respectively; p = 0.0137). Arthrometric measurements demonstrated a mean side-to-side difference (ΔATT) 1.87 (range 0.2 to 4.9) mm significantly decreased compared to ACLR 3.36 (range 1.2-5.6 mm; p = 0.0107). The mean Lysholm score was 85.3 points in the ACL repair group and 89.9 in ACLR group. No significant differences between ACL repair and ACLR were found for the Lysholm score. There was no association between AP laxity and clinical outcomes. There were two complications in the internal bracing group: one patient had re-rupture and was treated by ACLR, another had limited extension and had arthroscopic debridement.

CONCLUSIONS

Anterior tibial translation was significantly decreased after ACL repair. Additionally, the functional results after ACL repair with internal bracing were comparable with those after ACLR. It should be noted that the two complications occurred. The current study supports further development of ACL repair techniques.

Accuracy of magnetic resonance imaging in predicting anterior cruciate ligament tear location and tear degree

Purpose

The purpose of this study is to evaluate the reliability of magnetic resonance imaging (MRI) in predicting the location of ACL tears in preoperative planning for anterior cruciate ligament (ACL) repair.

Methods

Thirty-four patients who underwent ACL repair were retrospectively analyzed to compare intraoperative arthroscopic findings with preoperative MRIs.

Results

For identifying type I tears, the sensitivity of MRI was 9.0% and the accuracy of MRI was 8.8%. There was moderate interrater agreement between MRI findings for tear location and tear degree.

Conclusion

MRI alone may not necessarily be accurate in identifying which ACL tears are amenable to repair.

Study design

Retrospective case series; Level of Evidence: IV.

[Effectiveness of partial anterior cruciate ligament suture repair with wide awake local anesthesia no tourniquet technique]

OBJECTIVE

To investigate the effectiveness of partial anterior cruciate ligament (ACL) suture repair with wide awake local anesthesia no tourniquet (WALANT) technique.

METHODS

Between July 2017 and July 2019, 18 patients with partial ACL injury were admitted. There were 10 males and 8 females, with an average age of 40.5 years (range, 22-57 years). There were 5 cases on the left knee and 13 cases on the right knee. Forteen cases had a clear history of trauma or sports injury, and 4 cases had no obvious cause. The time from injury to operation was 1-6 months (median, 3 months). Partial ligament was sutured using WALANT technique under arthroscopy. The operation time, total hospital stay, and postoperative hospital stay were recorded. Lachman test and anterior drawer test were performed to evaluate the knee joint stability after treatment, and Lysholm and International Knee Documentation Committee (IKDC) scores were used to evaluate the knee function. Five-point Likert scaling were used to evaluate postoperative patient satisfaction.

RESULTS

The operation time was 30-100 minutes (mean, 64.2 minutes). The total hospital stay was 2-12 days (mean, 4.5 days). Postoperative hospital stay was 1-4 days (mean, 1.8 days). All incisions healed by first intention after operation, and no surgery-related complications occurred. All patients were followed up 12-36 months (mean, 19.1 months). Lachman test and anterior drawer test were negative after operation. Lysholm score and IKDC score at 6 and 12 months after operation were significantly higher than those before operation, and at 12 months after operation were higher than those at 6 months after operation, the differences were significant ( P<0.05). At last follow-up, according to five-point Likert scaling of patient satisfaction, 7 cases were very satisfied, 10 cases were relatively satisfied, and 1 case was general. The total patient satisfaction rate was 94.4% (17/18). MRI scan showed the good ligament tension.

CONCLUSION

Using WALANT technique to repair partial ACL injuries under arthroscopy can retain the patient's own ligament tissue to the maximum extent and achieve satisfactory short-term effectiveness.

Fibrin-Based Biomaterial Systems to Enhance Anterior Cruciate Ligament Healing

Anterior cruciate ligament (ACL) tears are a common and potentially career-ending injury, particularly for athletes and soldiers. Partial and complete ruptures of this ligament cause instability in the knee, and the ACL does not have the capacity for healing due, in part, to its position within the highly thrombolytic synovial fluid environment of the knee joint. Traditional methods of ACL reconstruction, such as graft replacement with attached bone anchors for bone integration, restore stability, but do not prevent the development of post-traumatic osteoarthritis. To enhance therapeutic treatment options, novel fibrin-based technologies and repair techniques have been recently explored and show promise for improved patient outcomes. Through modification of existing surgical methods, such as the use of fibrin glues incorporating growth factors and cells and the implementation of scaffolds containing platelet-rich plasma, platelet-rich fibrin, and other blood derivatives, surgeons are attempting to overcome the shortcomings of traditional treatments. This mini-review will detail current efforts using fibrin-based treatments and discuss opportunities to further enhance ACL healing.

Management of Partial Tears of the Anterior Cruciate Ligament: A Review of the Anatomy, Diagnosis, and Treatment

Partial anterior cruciate ligament (ACL) tears comprise an estimated 10% to 27% of isolated ACL injuries. Partial ACL tears may be challenging to clinically diagnose. We reviewed relevant studies focusing on the anatomy, diagnosis, imaging, and treatment of a partial injury with the goal of providing guidance to clinicians. Although a comprehensive patient history, thorough clinical examination, and imaging studies are helpful in arriving at a diagnosis, the benchmark for diagnosis remains visualization and examination of the ACL at the time of knee arthroscopy. Currently, limited data exist about the long-term outcomes of nonsurgical treatment. Some studies demonstrate that younger, active patients have the risk of progressing to a complete ACL rupture with conservative treatment. The decision to proceed with surgery is based on careful history and physical examination findings that suggest either a "functional" or "nonfunctional" ACL. Surgical treatment consists of augmenting the intact bundle with a selective bundle reconstruction versus a traditional ACL reconstruction. Selective bundle reconstruction has limited data available but is an option. The best evidence supports traditional ACL reconstruction for the surgical management of patients with documented nonfunctional partial tears of the ACL.

Arthroscopy Primary Double-Bundle Repair of Anterior Cruciate Ligament With Internal Brace Augmentation and a Knotless Anchor Implant

The primary repair technique of acute anterior cruciate ligament (ACL) tears has been controversially discussed over the past few decades. Many different suture techniques have been reported for ACL repair, but these procedures showed high re-rupture rates and poor results. Recently, the literature has reported excellent outcomes with primary ACL repair. There has been a resurging interest in modernizing and augmenting primary ACL repair. This article describes a technique that uses internal brace augmentation and a knotless anchor (Arthrex) implant for primary anatomic double-bundle ACL repair after an acute proximal ACL tear. This technique aims to advocate natural healing by the high-strength internal brace augmentation and knotless anchor as a provisional scaffold during the healing phase and early mobilization. This technique might be an alternative to conventional ACL reconstruction in the appropriate selection of patients.

Knotless Primary Anterior Cruciate Ligament Repair with Adjustable Loop Device and Internal Brace Augmentation

With the recent resurgence of primary anterior cruciate ligament repair, it is important to strive for optimal patient outcomes. This knotless primary repair procedure takes advantage of the use of an adjustable loop device, which allows for intraoperative retensioning by the surgeon. This technical advancement combined with augmentation with an internal brace could potentially minimize gap formation at the repair site, thereby increasing repair stability and ultimate outcome.

Return to Sport After ACL Reconstruction With a BTB Versus Hamstring Tendon Autograft: A Systematic Review and Meta-analysis

Background

Anterior cruciate ligament (ACL) tears are debilitating injuries frequently suffered by athletes. ACL reconstruction is indicated to restore knee stability and allow patients to return to prior levels of athletic performance. While existing literature suggests that patient-reported outcomes are similar between bone-patellar tendon-bone (BTB) and hamstring tendon (HT) autografts, there is less information comparing return-to-sport (RTS) rates between the 2 graft types.

Purpose

To compare RTS rates among athletes undergoing primary ACL reconstruction using a BTB versus HT autograft.

Study Design

Systematic review; Level of evidence, 4.

Methods

The MEDLINE, Embase, and Cochrane Library databases were searched, and studies that reported on RTS after primary ACL reconstruction using a BTB or HT autograft were included. Studies that utilized ACL repair techniques, quadriceps tendon autografts, graft augmentation, double-bundle autografts, allografts, or revision ACL reconstruction were excluded. RTS information was extracted and analyzed from all included studies.

Results

Included in the review were 20 articles investigating a total of 2348 athletes. The overall RTS rate in our cohort was 73.2%, with 48.9% returning to preinjury levels of performance and a rerupture rate of 2.4%. The overall RTS rate in patients after primary ACL reconstruction with a BTB autograft was 81.0%, with 50.0% of athletes returning to preinjury levels of performance and a rerupture rate of 2.2%. Patients after primary ACL reconstruction with an HT autograft had an overall RTS rate of 70.6%, with 48.5% of athletes returning to preinjury levels of performance and a rerupture rate of 2.5%.

Conclusion

ACL reconstruction using BTB autografts demonstrated higher overall RTS rates when compared with HT autografts. However, BTB and HT autografts had similar rates of return to preinjury levels of performance and rerupture rates. Less than half of the athletes were able to return to preinjury sport levels after ACL reconstruction with either an HT or BTB autograft.

The effect of thermosensitive hydrogel platelet-rich-plasma complex in the treatment of partial tear of anterior cruciate ligament in rat model

Background/Objective

The treatment of anterior cruciate ligament (ACL) partial tear is controversial. The reconstructive surgery is invasive while the prevalence of subsequent insufficiency after conservative treatment has been reported to range from 11% to 62%. Therefore, a new method that promotes tissue regeneration is needed. The aim of this study was to observe the healing of ACL partial tear biomechanically and histologically after the administration of a thermosensitive hydrogel platelet-rich-plasma (PRP) complex.

Methods

The complex was prepared according to a previously published protocol. One hundred and fifty 12-week-old male Sprague-Dawley rats were included and they were allocated into 4 groups. Lesion control group (Group 1), treatment group (Group 2), gel-only group (Group 3) and intact group (Group 4). Biomechanical testing, histological analysis (H&E and immunohistochemical staining) and scoring was performed.

Results

On gross observation, the treatment group showed a continuous ACL with slightly thickened synovium or a partially healed ACL at 6-week follow up. In the biomechanical testing at 6 weeks after surgery, the failure load of the treatment group was significantly superior when compared with the lesion control group (52.7±10.8N vs. 41.6±7.8N, p<0.01), but the failure load was not restored to level of the intact group (52.7±10.8N vs. 61.5±9.1N, p=0.037). The maturity index of wound sites showed no significant inter-group differences at any timepoints. However, an increased expression of vascular endothelial growth factor (VEGF) and pro-collagen I was detected.

Conclusion

The thermosensitive hydrogel-PRP was shown to be effective in enhancing the healing of ACL partial tear in the rat model, and potentially this complex can be used as a treatment for patients with ACL partial tear.

The translational potential of this article

The thermosensitive hydrogel-PRP is potentially translated to clinical use to treat patients with ACL partial tear by injection under arthroscopy or ultrasound guiding.

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 Using a Knotless Suture Implant

Recent orthopedic literature has shown that primary repair for femoral-sided avulsion tears of the anterior cruciate ligament (ACL) can be successful. Primary ACL repair avoids invasive reconstruction techniques, graft-site morbidity, and the loss of native anatomy while producing excellent results in appropriately selected patients. Here we describe our patient selection parameters, ACL repair technique, and rehabilitation protocol.

Is Primary Arthroscopic Repair Using the Pulley Technique an Effective Treatment for Partial Proximal ACL Tears?

BACKGROUND

Attention has recently been paid to primary arthroscopic repair to treat ACL tears because of the disadvantages associated with reconstruction. However, there remain many unanswered questions and concerns about its application in the treatment of ACL tears.

QUESTIONS/PURPOSES

(1) Does primary arthroscopic repair using the pulley technique result in satisfactory ROM (a functional ROM with a flexion contracture of 30° or less), knee stability, and functional scores in patients with partial proximal ACL tears? (2) What complications are associated with primary arthroscopic repair using the pulley technique in patients with partial proximal ACL tears?

METHODS

Between January 2014 and March 2016, we treated 23 patients surgically who had partial proximal ACL tears and excellent tissue quality (defined as a remnant with mild interstitial tearing and the ability to hold sutures). All patients meeting those two criteria were treated using primary arthroscopic repair using the pulley technique. During that period, this represented 13% (23 of 183) of the patients we treated surgically for an ACL tear. Patients were excluded if they had other ACL tear types, insufficient tissue quality (defined as a severely torn remnant that was not strong enough to hold sutures), multi-ligamentous injuries, or substantial arthrosis (chondromalacia greater than Outerbridge grade 3, most of which underwent conversion to ACL reconstruction). Clinical outcomes were assessed using ROM, the anterior drawer test, the Lachman test, Lysholm score, Tegner activity score, IKDC subjective score, and radiographs. Twenty-one patients were observed for a mean (range) period of 36 months (25-49), and two were lost to follow-up.

RESULTS

At the most-recent follow-up examination, all patients achieved full extension and only one patient lacked full flexion, with a flexion contracture of 10°. Twenty patients had no instability on the anterior drawer test and Lachman test findings, and one patient had a 1 + anterior drawer test. The mean Lysholm score improved from a mean ± SD of 71 ± 9 before surgery to 94 ± 6 (mean difference 23 points [95% CI 20 to 25]; p < 0.001) at latest follow-up. The IKDC subjective score improved from 64 ± 10 to 86 ± 11 points (mean difference 22 points; p < 0.001). We found no difference in the Tegner score from before surgery to latest follow-up (6.3 ± 1.2 versus 6.1 ± 1.2; mean difference 0.2; p = 0.056). One patient re-ruptured his ACL 2 months after surgery in military training during an obstacle race. No complications such as infection, thrombosis, stiffness, patellofemoral pain, or implant failure were observed.

CONCLUSIONS

Primary arthroscopic repair using the pulley technique can achieve short-term clinical success in a carefully selected (the selection process includes first identifying the ACL injury pattern preoperatively with MRI, then confirming the diagnosis under arthroscopy, and deciding whether to perform a repair intraoperatively) subset of patients with partial proximal ACL tears and excellent tissue quality (defined as a remnant with mild interstitial tearing and the ability to hold sutures). Despite the promising clinical outcomes of our study, this technique should not be widely adopted unless it has been compared directly with ACL reconstruction, so future studies should be conducted to compare the clinical outcomes between this technique and ACL reconstruction, and longer-term follow-up is necessary to identify whether there is deterioration in the clinical outcomes over time.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Anterior Cruciate Ligament Reconstruction with Platelet-Rich Plasma: A Systematic Review of Randomized Control Trials

PURPOSE

To perform a systematic review of the randomized controlled trials (RCTs) evaluating the efficacy of platelet-rich plasma (PRP) to augment anterior cruciate ligament (ACL) reconstruction.

METHODS

Two independent reviewers screened the MEDLINE, The Cochrane Library, and EMBASE databases using Preferred Reporting for Systematic Reviews and Meta-Analyses guidelines for applicable RCTs evaluating the efficacy of PRP in ACL reconstruction. A meta-analysis was performed on the papers involving bone-patellar tendon-bone (BPTB) grafting.

RESULTS

Thirteen RCTs fulfilled the inclusion criteria involving 765 patients. There was no clinical improvement (Tegner, Lysholm, Knee Injury and Osteoarthritis Outcome Score, or International Knee Documentation Committee scores) in any of the 7 studies evaluating PRP alongside the hamstring tendon autograft ACL reconstructions versus the control. Two studies evaluating PRP for hamstring tendon autograft demonstrated significantly improved magnetic resonance imaging findings. Two studies analyzed the use of PRP with allograft ACL reconstruction showed no clinical, biochemical, or radiologic improvements in postoperative follow-up. No functional improvements were found when PRP was used alongside BPTB in 4 studies. There was no significant difference in visual analog scale score in the BPTB group (1.1 vs 1.5, P = .18), or tibial filling defects (P = .30).

CONCLUSIONS

This study found that the current level I evidence does not support the use of PRP to improve graft healing, improve donor-site morbidity, reduce postoperative pain levels, or improve functional outcomes following ACL reconstruction.

LEVEL OF EVIDENCE

Level I; systematic review of level I evidence.

Arthroscopic primary repair of the anterior cruciate ligament in adults: a systematic review

BACKGROUND

The most common procedure to manage a torn anterior cruciate ligament (ACL) is surgical reconstruction. Primary repair of the ACL is returning on the forefront in the management of acute ACL, aiming to be less invasive and preserve the original ligament. Several techniques have been reported; the present systematic review investigates the clinical outcomes of ACL primary repair in adults.

SOURCES OF DATA

Following an electronic search through Medline, Cochrane and Google Scholar databases, articles of interest were retrieved and evaluated, including case series, retrospective studies, case-control studies and randomized controlled trials. The main outcome data were extracted and summarized in tables and text. The methodology of the studies was assessed using the Coleman methodology score (CMS).

AREAS OF AGREEMENT

Of the articles included, one was of level I, two of level III and the remaining of level IV. The direct intraligamentary stabilization technique was the most widely and accurately reported technique, with acceptable success and improvement of functional outcomes. The CMS averaged 58.75 (range 48 to 69), with no significant association with year of publication (Pearson's regression r = -0.397, P = 0.207).

AREAS OF CONTROVERSY

Concerning stump sutures and suture anchors repair, although leading to good results, also in comparison with ACL reconstruction, no sufficient evidence was available to support these techniques.

GROWING POINTS

The overall good results were reported also for other techniques are not supported by adequate evidence. More and better trials are required to improve our knowledge and understanding in this controversial area.