The "ligamentization" process in anterior cruciate ligament reconstruction: what happens to the human graft? A systematic review of the literature

A New Tissue Engineering Strategy to Promote Tendon-bone Healing: Regulation of Osteogenic and Chondrogenic Differentiation of Tendon-derived Stem Cells

In the field of sports medicine, repair surgery for anterior cruciate ligament (ACL) and rotator cuff (RC) injuries are remarkably common. Despite the availability of relatively effective treatment modalities, outcomes often fall short of expectations. This comprehensive review aims to thoroughly examine current strategies employed to promote tendon-bone healing and analyze pertinent preclinical and clinical research. Amidst ongoing investigations, tendon-derived stem cells (TDSCs), which have comparatively limited prior exploration, have garnered increasing attention in the context of tendon-bone healing, emerging as a promising cell type for regenerative therapies. This review article delves into the potential of combining TDSCs with tissue engineering methods, with ACL reconstruction as the main focus. It comprehensively reviews relevant research on ACL and RC healing to address the issues of graft healing and bone tunnel integration. To optimize tendon-bone healing outcomes, our emphasis lies in not only reconstructing the original microstructure of the tendon-bone interface but also achieving proper bone tunnel integration, encompassing both cartilage and bone formation. In this endeavor, we thoroughly analyze the transcriptional and molecular regulatory variables governing TDSCs differentiation, incorporating a retrospective analysis utilizing single-cell sequencing, with the aim of unearthing relevant signaling pathways and processes. By presenting a novel strategy rooted in TDSCs-driven osteogenic and chondrogenic differentiation for tendon-bone healing, this study paves the way for potential future research avenues and promising therapeutic applications. It is anticipated that the findings herein will contribute to advancing the field of tendon-bone healing and foster the exploration of TDSCs as a viable option for regenerative therapies in the future.

Comparison of "ligamentization" process between preserved insertion hamstring tendon autograft and bone-patellar tendon-bone autograft

BACKGROUND

Ligamentization is a complex process and effect of preservation of hamstring tendon graft insertion on this process is not well studied. Present study was conducted to analyze and compare the ligamentization of semitendinosus gracilis graft with preserved tibial insertion (STGPI) and bone-patellar tendon-bone (BPTB) autografts.

METHODS

A total of 50 sportspeople who underwent ACL reconstruction using either BPTB (group A; n = 25) or STGPI (group B; n = 25) autografts were included in the study. Contrast enhanced MRI was done at 8 months and 14 months post-ACL reconstruction to evaluate the ligamentization using Signal noise quotient (SNQ), graft intensity and enhancement index. Clinical outcomes (Lysholm score) and knee laxity were also assessed at 8 months and 14 months.

RESULTS

18/23 (78%) patients in group A and 14/23 (61%) patients in group B had hyperintense graft signal at 8 months (n.s.) and at 14 months, 1/23 patients in group A and none of the patients in group B had hyperintense graft. SNQ at 8 months was 3.6 ± 2 and 3.7 ± 2 in group A and B respectively (n.s.) and at 14 months, SNQ was 2.5 ± 1.5 in group A and 2.4 ± 1.3 in group B (n.s.). Enhancement index at 8 months was 1.5 ± 0.3 and 1.2 ± 0.3 in group A and B respectively (p = 0.0001). Enhancement index at 14 months was 1.21 ± 0.2 in group A and 1.07 ± 0.2 in group B (p = 0.003). Functional outcomes and knee laxity were comparable in both the groups at 8 and 14 months (n.s.).

CONCLUSION

Both the grafts i.e. BPTB and STGPI are similar in terms of rate and extent of ligamentization. Clinical outcomes and knee laxity are also comparable between two grafts.

Lateral extra-articular tenodesis does not enhance ACL graft healing, however, does reduce graft tunnel widening

PURPOSE

The study hypothesized that the addition of lateral extra-articular tenodesis (LEAT) in anterior cruciate ligament reconstruction (ACLR) had a significant effect on ACL graft healing.

METHODS

A total of 80 patients were divided into two cohorts matched for gender, age, body mass index, time from surgery to post-operative MRI and graft diameter. Forty patients underwent ACL reconstruction alone, while 40 underwent ACLR in addition to LEAT. Patients underwent a magnetic resonance imaging scan at 12 months post-surgery; tunnel apertures were measured using multiplanar reformation, graft healing was assessed using signal-to-noise quotient (SNQ) in three regions of interest and finally graft maturity and integration were classified using the Howell and Ge scale, respectively. In addition, clinical evaluation and patient-reported outcome measures were collected.

RESULTS

The mean femoral tunnel widening at 12 months post-surgery was 39.8 ± 14.0% in the ACLR + LEAT group and 55.2 ± 12.7% in the ACLR alone group (p < 0.05). The mean tibial tunnel widening was 29.3 ± 12.7% in the ACLR + LEAT group and 44.4 ± 12.1% in the ACLR group (p < 0.05). The mean adjusted graft SNQ was 9.0 ± 14.9 in the ACLR + LEAT group and 9.5 ± 11.4 in the ACLR group (n.s.).

CONCLUSION

At 1 year post-operatively, we noted significantly less femoral and tibial tunnel widening in the ACLR + LEAT group. LEAT did not result in a statistically significant effect on graft healing.

LEVEL OF EVIDENCE

Level III.

Rehabilitation and return-to-sport after anterior cruciate ligament injury and reconstruction: Exploring physical therapists' approaches in Argentina

OBJECTIVES

To investigate the current clinical practice regarding pre- and post-surgical rehabilitation and return to sport (RTS) criteria following anterior cruciate ligament reconstruction (ACLR).

DESIGN

Cross-sectional design. Online survey.

SETTING

Survey platform.

PARTICIPANTS

Argentinian physical therapists (PTs).

OUTCOME MEASURES

The survey consisted of a combination of 39 open- and closed-ended questions, divided across 3 sections: (1) demographic and professional information, (2) clinical practice and rehabilitation strategies, and (3) return-to-running (RTR) and RTS.

RESULTS

A total of 619 PTs completed the survey. Considerable variability was observed in preoperative rehabilitation, criteria used for rehabilitation progression and RTS decision-making criteria used by PTs. From the total surveyed, 336 (54.3%) carried out RTS assessment in their clinical practice. Most of PTs (53.3%) use visual estimation to assess knee range of motion. Only 20% of the PTs reported incorporating patient-reported outcome measures in their decision-making. From PTs who use strength assessment as a criterion of RTS (68.8%), 16.6% extrapolate this from jump tests and 15.3% use manual muscle testing. Less than the 50% of the PTs recommended nine months or more to allow patients to RTS.

CONCLUSIONS

Current rehabilitation practices of Argentinian PTs following ACLR are largely variable and not aligned with current evidence and scientific guidelines. To achieve better rehabilitation and RTS practices better knowledge dissemination and implementation are required.

Intra-Articular Platelet-Rich Plasma Injection After Anterior Cruciate Ligament Reconstruction: A Randomized Clinical Trial

Importance

Platelet-rich plasma (PRP) has been considered a promising treatment for musculoskeletal disorders. The effects of PRP on clinical outcomes of anterior cruciate ligament reconstruction (ACLR) are controversial.

Objective

To compare subjective outcomes and graft maturity in patients undergoing ACLR with and without postoperative intra-articular PRP injection.

Design, Setting, and Participants

This surgeon- and investigator-masked randomized clinical trial included patients treated at a national medical center in China who were aged 16 to 45 years and scheduled to undergo ACLR. Participants were enrolled between March 21, 2021, and August 18, 2022, and followed up for 12 months, with the last participant completing follow-up on August 28, 2023.

Interventions

Participants were randomized 1:1 to the PRP group (n = 60), which received 3 doses of postoperative intra-articular PRP injection at monthly intervals, or to the control group (n = 60), which did not receive postoperative PRP injection. Both groups had the same follow-up schedule.

Main Outcomes and Measures

The primary outcome was the mean score for 4 subscales of the Knee Injury and Osteoarthritis Outcome Score (KOOS4) (range, 0-100, with higher scores indicating better knee function and fewer symptoms) at 12 months postoperatively. Secondary outcomes were patient-reported outcomes, graft maturity (on magnetic resonance imaging), and physical examinations at 3, 6, and 12 months.

Results

Among the 120 randomized participants (mean [SD] age, 29.0 [8.0] years; 84 males [70%]), 114 (95%) were available for the primary outcome analysis. The mean KOOS4 scores at 12 months were 78.3 (SD, 12.0; 95% CI, 75.2-81.4) in the PRP group and 76.8 (SD, 11.9; 95% CI, 73.7-79.9) in the control group (adjusted mean between-group difference, 2.0; 95% CI, -2.3 to 6.3; P = .36). Secondary outcomes were not statistically significantly different between the 2 groups except for sports and recreation level and graft maturity at 6 months. Intervention-related adverse events included pain at the injection site and knee swelling after injection.

Conclusions and Relevance

In this randomized clinical trial among patients undergoing ACLR, the addition of postoperative intra-articular PRP injection did not result in superior improvement of knee symptoms and function at 12 months compared with no postoperative injection. Further studies are required to determine appropriate indications for PRP in musculoskeletal disorders.

Trial Registration

Chinese Clinical Trial Registry Identifier: ChiCTR2000040262.

Understanding Tendon Fibroblast Biology and Heterogeneity

Tendon regeneration has emerged as an area of interest due to the challenging healing process of avascular tendon tissue. During tendon healing after injury, the formation of a fibrous scar can limit tendon strength and lead to subsequent complications. The specific biological mechanisms that cause fibrosis across different cellular subtypes within the tendon and across different tendons in the body continue to remain unknown. Herein, we review the current understanding of tendon healing, fibrosis mechanisms, and future directions for treatments. We summarize recent research on the role of fibroblasts throughout tendon healing and describe the functional and cellular heterogeneity of fibroblasts and tendons. The review notes gaps in tendon fibrosis research, with a focus on characterizing distinct fibroblast subpopulations in the tendon. We highlight new techniques in the field that can be used to enhance our understanding of complex tendon pathologies such as fibrosis. Finally, we explore bioengineering tools for tendon regeneration and discuss future areas for innovation. Exploring the heterogeneity of tendon fibroblasts on the cellular level can inform therapeutic strategies for addressing tendon fibrosis and ultimately reduce its clinical burden.

Evaluation of Failed ACL Reconstruction: An Updated Review

Failure rates among primary Anterior Cruciate Ligament Reconstruction (ACLR) range from 3.2% to 11.1%. Recently, there has been increased focus on surgical and anatomic considerations which predispose patients to failure, including excessive posterior tibial slope (PTS), unaddressed high-grade pivot shift, and improper tunnel placement. The purpose of this review was to provide a current summary and analysis of the literature regarding patient-related and technical factors surrounding revision ACLR, rehabilitation considerations, overall outcomes and return to sport (RTS) for patients who undergo revision ACLR. There is a convincingly higher re-tear and revision rate in patients who undergo ACLR with allograft than autograft, especially amongst the young, athletic population. Unrecognized Posterior Cruciate Ligament (PLC) injury is a common cause of ACLR failure and current literature suggests concurrent operative management of high-grade PLC injuries. Given the high rates of revision surgery in young active patients who return to pivoting sports, the authors recommend strong consideration of a combined ACLR + Anterolateral Ligament (ALL) or Lateral extra-articular tenodesis (LET) procedure in this population. Excessive PTS has been identified as an independent risk factor for ACL graft failure. Careful consideration of patient-specific factors such as age and activity level may influence the success of ACL reconstruction. Additional technical considerations including graft choice and fixation method, tunnel position, evaluation of concomitant posterolateral corner and high-grade pivot shift injuries, and the role of excessive posterior tibial slope may play a significant role in preventing failure.

Suture Tape Augmentation of Posterior Cruciate Ligament Reconstruction Shows Improved Biomechanical Stability With Equivalent Outcome and Complication Rates: A Scoping Review

PURPOSE

To assess the current literature surrounding suture tape augmentation (STA) of posterior cruciate ligament reconstruction (PCLR) with additional evaluation of PCLR+STA in clinical practice.

METHODS

A systematic search of 3 databases (PubMed, EMBASE, and Web of Science Core Collection) was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was completed in April 2023 to identify studies related to PCLR+STA. Surgical technique, animal, biomechanical, and clinical studies were included for review with quality appraisal conducted according to study design.

RESULTS

A total of 380 articles were identified in the search, 6 of which met inclusion criteria. Biomechanical studies showed a significant reduction in posterior tibial translation with STA of PCLR in multiple studies. STA was found to decrease total elongation by 45% to 58% in multiple studies; increased load to failure was seen with STA as well in 1 study. Clinical studies showed equivalent or improved patient-reported outcomes with STA of PCLR compared with PCLR alone.

CONCLUSIONS

Biomechanical studies offer evidence showing the beneficial load-sharing properties of STA such as increased strength and ultimate load with decreased elongation of the graft, especially with larger forces. Clinical evidence illustrates improved or equivalent patient-reported outcomes to standard PCLR with no difference in complication rate.

CLINICAL RELEVANCE

STA of PCLR offers an opportunity to improve initial graft stability during the early healing phase through load sharing between the augmentation and the graft.

Better Safe Than Sorry? A Systematic Review with Meta-analysis on Time to Return to Sport After ACL Reconstruction as a Risk Factor for Second ACL Injury

OBJECTIVE: To compare the time to return to sport (RTS) between patients who did and did not suffer a second anterior cruciate ligament (ACL) injury after ACL reconstruction. DESIGN: Etiology systematic review with meta-analysis. LITERATURE SEARCH: Cochrane Library, Embase, Medline, AMED, and PEDro databases were searched in August 2021 and again in November 2022. STUDY SELECTION CRITERIA: Clinical studies reporting time to RTS after ACL reconstruction and second ACL injury were eligible. DATA SYNTHESIS: We pooled continuous data (time [months] and proportions [%]), with random-effects meta-analyses. Pooled estimates were summarized in forest plots. A qualitative data synthesis was also performed. RESULTS: Twenty-one studies were included in the meta-analysis and 33 in the qualitative synthesis. Pooled incidence of second ACL injury was 16.9% (95% confidence interval [CI]: 12.8, 21.6). Patients who suffered a second ACL injury returned to sport significantly earlier (25 days; 95% CI: 9.5, 40.4) than those who did not suffer another injury. There was no difference in time to RTS for professional athletes who suffered a second ACL injury and those who did not. The certainty of evidence was very low. CONCLUSION: There was very low-certainty evidence that patients who suffered a second ACL injury had returned to sport 25 days earlier than patients who did not have another injury. For professional athletes, there was no difference in time to RTS between athletes who suffered a second ACL injury and athletes who did not. J Orthop Sports Phys Ther 2024;54(3):1-15. Epub 30 November 2023. doi:10.2519/jospt.2023.11977.

MRI Assessment of Tendon Graft After Lateral Ankle Ligament Reconstruction: Does Ligamentization Exist?

BACKGROUND

No description exists in the literature about the normal evolution of tendon graft after a lateral ankle ligament (LAL) reconstruction.

PURPOSE

To assess the magnetic resonance imaging (MRI) characteristics and the evolution of the tendon graft during different moments in the follow-up after an endoscopic reconstruction of the LAL.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This prospective study included 37 consecutive patients who underwent an endoscopic reconstruction of the LAL with an autograft using the gracilis tendon to treat chronic ankle instability (CAI) resistant to nonoperative treatment (CAI group) and 16 patients without ankle instability (control group). All patients in the CAI group underwent a postoperative assessment at 6, 12, and 24 months using the Karlsson score and MRI examination. Only patients with good and excellent results were included in the study. Graft assessment consisted of qualitative measurements and quantitative evaluations of the reconstructed anterior talofibular ligament (RATFL) and reconstructed calcaneofibular ligament (RCFL), including signal-to-noise quotient (SNQ) and contrast-to-noise quotient (CNQ) measurements in proton density-fat suppressed (PD-FS) and T1-weighted sequences. The analysis of variance test was used to compare the SNQ and the CNQ at different time points for each sequence.

RESULTS

The MRI signal at 6 months was increased compared with that of the control group. Next, a significant signal decrease from 6 to 24 months was noted on PD-FS and T1-weighted images. SNQ measurements on PD-FS weighted images for both the RATFL and the RCFL demonstrated a significantly higher signal (P < .01 and P = .01, respectively) at 6 months compared with that of the control group. Subsequently, the signal decreased from 6 to 24 months. Similarly, CNQ measurements on PD-FS weighted images for both the RATFL and the RCFL demonstrated a significantly higher signal (P < .01 and P < .01, respectively) at 6 months compared with that of the control group. Subsequently, the signal decreased from 6 to 24 months.

CONCLUSION

The present study demonstrated an evolution of the MRI characteristics, suggesting a process of graft maturation toward ligamentization. This is important for clinical practice, as it suggests an evolution in graft properties and supports the possibility of creating a viable ligament.

Plastic and elastic biomechanical properties of anterior cruciate ligament autografts

BACKGROUND

Anterior cruciate ligament (ACL) rupture is a common orthopedic injury, occurring in roughly 68.6 per 100,000 persons annually, with the primary treatment option being ACL reconstruction. However, debate remains about the appropriate graft type for restoring the native biomechanical properties of the knee. Furthermore, plastic graft elongation may promote increased knee laxity and instability without rupture. This study aims to investigate the plastic properties of common ACL-R graft options.

METHODS

Patellar tendon (PT), hamstring tendon (HT), and quadriceps tendon (QT) grafts were harvested from 11 cadaveric knees (6 male and 5 female) with a mean age of 71(range 55-81). All grafts were mechanically tested under uniaxial tension until failure to determine each graft's elastic and plastic biomechanical properties.

RESULTS

Mechanically, the QT graft was the weakest, exhibiting the lowest failure force and the lowest failure stress (QT < HT, p = 0.032). The PT was the stiffest of the grafts, having a significantly higher stiffness (PT > QT, p = 0.0002) and Young's modulus (PT > QT, p = 0.001; PT > HT, p = 0.041). The HT graft had the highest plastic elongation at 4.01 ± 1.32 mm (HT > PT, p = 0.002). The post-yield behavior of the HT tendon shows increased energy storage capabilities with the highest plastic energy storage (HT > QT, p = 0.012) and the highest toughness (HT > QT, p = 0.032).

CONCLUSION

Our study agrees with prior studies indicating that the failure load of all grafts is above the requirements for everyday activities. However, grafts may be susceptible to yielding before failure during daily activities. This may result in the eventual loss of functionality for the neo-ACL, resulting in increased knee laxity and instability.

The role of peroneus longus (PL) autograft in the reconstruction of anterior cruciate ligament (ACL): A comprehensive narrative review

Background

Peroneus longus tendon (PLT) is a known graft utilised in the ligamentous reconstructions of knee. The current review was performed to analyze the available evidence regarding PLT in the arthroscopic anterior cruciate ligament (ACL) reconstruction.

Methods

A comprehensive search of literature was performed on March 1, 2023 using 5 databases (for manuscripts published between 2010 and 2023). All studies reporting ACL reconstruction with PL graft in adults ≥18 years were considered; and final studies were shortlisted based on specific exclusion criteria.

Results

The search identified 684 articles, among which 26 manuscripts were finally selected. PLT has been used in primary ACL reconstruction (ACLR), revision ACLR, ACLR in multiligamentous injuries and those at risk for anterior knee pain. The full-thickness PLT graft is variable in its dimensions with the mean size ranging between 7 and 8.8 mm (half-PLT grafts ≤8.1 mm). The ultimate strength of doubled PLT graft is significantly higher than native ACL and comparable to the quadrupled hamstring.There was statistically insignificant difference in the laxity and functional outcome of knee following ACLR with PLT, as compared with other autografts (p > 0.05). PLT harvest is associated with satisfactory clinical foot and ankle outcomes, as well as excellent regenerative ability. Overall, studies have demonstrated lower complications with PLT (p < 0.05).

Conclusion

The dimensions of harvested PLT graft are more consistent than HT. It has similar functional outcome and survival, as compared to other autografts. It also has lower risk for donor-site morbidity and lower complications than HT. PLT is a promising, alternative autograft choice in patients undergoing ACLR.

Optimising the Early-Stage Rehabilitation Process Post-ACL Reconstruction

Outcomes following anterior cruciate ligament reconstruction (ACLR) need improving, with poor return-to-sport rates and a high risk of secondary re-injury. There is a need to improve rehabilitation strategies post-ACLR, if we can support enhanced patient outcomes. This paper discusses how to optimise the early-stage rehabilitation process post-ACLR. Early-stage rehabilitation is the vital foundation on which successful rehabilitation post-ACLR can occur. Without high-quality early-stage (and pre-operative) rehabilitation, patients often do not overcome major aspects of dysfunction, which limits knee function and the ability to transition through subsequent stages of rehabilitation optimally. We highlight six main dimensions during the early stage: (1) pain and swelling; (2) knee joint range of motion; (3) arthrogenic muscle inhibition and muscle strength; (4) movement quality/neuromuscular control during activities of daily living (5) psycho-social-cultural and environmental factors and (6) physical fitness preservation. The six do not share equal importance and the extent of time commitment devoted to each will depend on the individual patient. The paper provides recommendations on how to implement these into practice, discussing training planning and programming, and suggests specific screening to monitor work and when the athlete can progress to the next stage (e.g. mid-stage rehabilitation entry criteria).

Outcomes of hamstring graft with preserved tibial insertion for ACL reconstruction: systematic review and meta-analysis

PURPOSE

Evaluate the outcomes of ACL (Anterior Cruciate Ligament) reconstruction techniques that use a hamstring graft with a preserved tibial insertion and compare them to standard techniques.

METHODS

A systematic literature review and meta-analysis was done of the PubMed, MEDLINE, Cochrane and Ovid databases to identify published clinical studies on ACL reconstruction in which a non-detached hamstring tendon (NDHT) was used as a graft and to compare them to studies in which a detached hamstring tendon (DHT) or other techniques were used. The eligible studies were analyzed for the knee laxity, Lachman test, pivot shift test, joint range of motion, anterior drawer, pain, re-tear, revision surgery, Lysholm score, Tegner score, ACL-RSI scale, KOOS, IKDC, SNQ and Howell scale.

RESULTS

Twelve articles in which NDHT was used for ACL reconstruction were analyzed. There was no significant difference between NDHT and DHT in the Lachman > 1 (p = .07), pivot shift test > 1 (p = .40), re-tears (p = .62), pain (p = .85) and the Tegner score (p = .95). However, the outcomes were somewhat better with the NDHT technique for the Lachman (RR = 0.30; 95% CI 0.08-1.12), pivot shift test (RR = 0.50; 95% CI 0.10-2.49) and re-tears (RR = 0.66; 95% CI 0.13-3.42). The other criteria were not included in the meta-analysis because of lack of data or because specific outcome scores were used in each article.

CONCLUSION

NDHT techniques provide similar results to DHT for ACL reconstruction and tend to produce better stability and a lower re-tear rate.

Internal brace augmentation reconstruction versus standard anterior cruciate ligament reconstruction: a randomised controlled clinical trial study protocol

INTRODUCTION

Anterior cruciate ligament (ACL) rupture is one of the most common knee injuries in sports, and the gold standard for treating ACL rupture is tendon graft reconstruction. Internal brace technology is being used nowadays for ligament repair; however, more relevant in vivo clinical evidence is required for using internal brace technology in ACL reconstruction (ACLR). We conducted a randomised controlled trial to investigate the clinical efficacy of internal brace technology in ACLR.

METHODS AND ANALYSIS

This randomised, parallel-controlled trial included patients with ACL rupture who underwent inpatient surgery at the Department of Orthopaedics, Xiangya Hospital, Central South University. Random number table method was used to assign the participants to either the test or the control group. The test group underwent ACLR using the internal brace technique, whereas the control group underwent standard ACLR. Uniform postoperative rehabilitation protocol was used for both the groups. Patient-reported outcomes included preoperative baseline and postoperative recovery at 1, 3, 6, 12 and 24 months. The primary outcome was International Knee Documentation Committee function from baseline (ACL rupture) to 6 months postoperatively. Secondary outcomes included (1) other patient outcome reporting metrics, Lysholm knee score, Knee Injury and Osteoarthritis Outcome Score and Visual Analog Scale; (2) the use of Kneelax3 knee stabiliser to assess knee stability; (3) occurrence of adverse events, such as graft refraction or symptomatic instability, postoperative infection and contralateral injury and (4) magnetic resonance images at 12 and 24 months after ACLR.

ETHICS AND DISSEMINATION

This trial was approved by the Medical Ethics Committee of the Xiangya Hospital of Central South University on 26 October 2021. Data will be published in peer-reviewed journals and presented at national and international conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2200057526.

Comparison of Revision ACL Reconstruction Using Iliotibial Band Augmented With Allograft Versus Bone-Patellar Tendon-Bone Autograft With Lateral Extra-articular Tenodesis

Background

Bone-patellar tendon-bone (BTB) anterior cruciate ligament reconstruction (ACLR) is one of the conventional techniques in the revision setting especially after a primary hamstring tendon graft. The use of the iliotibial band (ITB) augmented with allograft (AG) is an encouraging graft alternative for ACLR in terms of clinical and biomechanical data in the literature.

Purpose

To compare the clinical outcomes of BTB graft with lateral extra-articular tenodesis, modified Lemaire (BTB-LET), and an ITB graft augmented with hamstring AG (ITB-AG) in the setting of revision ACLR.

Study Design

Cohort study; Level of evidence, 3.

Methods

Descriptive data and clinical outcomes were prospectively collected from patients who underwent revision ACLR with either the BTB-LET or ITB-AG technique between 2012 and 2020 and who had a minimum follow-up of 2 years. The clinical outcomes were assessed by the Lysholm, Tegner, Anterior Cruciate Ligament-Return to Sport after Injury, International Knee Documentation Committee subjective knee evaluation form, and Knee injury and Osteoarthritis Outcome Score. Return to sports, complications, and revisions were also analyzed.

Results

A total of 167 patients were included, with 106 patients in the BTB-LET group and 61 patients in the ITB-AG group. There were no significant group differences in sociodemographic characteristics; however, the mean follow-up was significantly longer in the BTB-LET compared with the ITB-AG group (52.0 vs 38.8 months, respectively; P = .0001). There were no significant differences in postoperative outcome scores; however, patients in the ITB-AG group had a higher rate of return to competitive pivoting sports (32.8% vs 17.9%; P = .0288) and a higher overall rate of return to preinjury sport (63.9% vs 47.2%; P = .0365). Complications, including revisions for meniscal or chondral lesions and retears (8 [8.3%] in the BTB-LET group and 2 [4.0%] in the ITB-AG group), were not significantly different. All retears were due to sports-related accidents.

Conclusion

In this study, ITB-AG was not different from BTB-LET in terms of functional outcomes scores but allowed better return to sport rate. Performing ITB-AG reconstruction in the setting of revision ACLR appears to be safe, effective, and associated with a satisfying return-to-sports rate.

The Effect of Aging on Outcomes after Posterior Cruciate Ligament Reconstruction: Older (≥ 50 Years) Versus Younger (< 50 Years) Patients

Background

This study aimed to evaluate the clinical and radiological outcomes after posterior cruciate ligament (PCL) reconstruction in ≥ 50-year-old patients.

Methods

This retrospective case-control study reviewed 28 patients (age, ≥ 50 years) who underwent PCL reconstruction from 2004 to 2018. These patients were 1 : 1 matched to < 50-year-old patients by sex. Clinical, radiological, and survivorship outcomes of the patients were assessed at the final follow-up. Failure of PCL reconstruction was defined as the requirement for additional surgery (revision PCL reconstruction, high tibial osteotomy, or arthroplasty) due to unrelieved symptoms or grade III instability on stress radiographs.

Results

The mean follow-up periods (± standard deviation) in < 50- and ≥ 50-year-old patients were 3.9 ± 1.0 years and 3.6 ± 1.9 years, respectively (p = 0.583). In < 50- and ≥ 50-year-old patients, the mean International Knee Documentation Committee scores were 64.1 ± 10.3 and 53.5 ± 17.3; mean Lysholm scores were 81.4 ± 13.0 and 66.3 ± 21.5; and mean Tegner activity scores were 6.1 ± 1.4 and 4.8 ± 1.7, respectively (p = 0.032, p = 0.018, and p = 0.016, respectively). Side-to-side differences in posterior translation on Telos stress radiographs at the final follow-up were 4.4 ± 1.4 mm and 6.9 ± 3.0 mm in < 50- and ≥ 50-year-old patients, respectively (p < 0.001). According to Kaplan-Meier analysis, the failure-free survival rates of both groups were significantly different in the follow-up period (p = 0.014). The failure-free survival rates for < 50- and ≥ 50-year-old patients were 100% and 78.6%, respectively.

Conclusions

Clinical, radiological, and survivorship outcomes were inferior among ≥ 50-year-old patients after PCL reconstruction. Thus, surgeons should be careful when deciding and performing PCL reconstruction in patients 50 years old or over.

Single Bundle Anterior Cruciate Ligament With Anterolateral Ligament Reconstruction Yields Similar Clinical and Radiographic Results at Minimum 2-Year Follow-Up Versus Double Bundle Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Controlled Trial

PURPOSE

To compare the clinical, radiographic, and second-look arthroscopic outcomes between double-bundle (DB) anterior cruciate ligament (ACL) reconstruction (DB group) and combined single-bundle (SB) ACL and anterolateral ligament (ALL) reconstruction (SB + ALL group) by a prospective randomized controlled trial.

METHODS

From May 2019 to June 2020, 84 patients were enrolled in this study. Among them, 10 were lost to follow-up. Thirty-six and 38 patients were successfully allocated to the DB (mean follow up 27.3 ± 4.2 months) and SB + ALL groups (27.2 ± 4.5 months), respectively. The preoperative and postoperative Lachman test, pivot shift test, anterior translation on stress radiographs, KT-2000 arthrometer, Lysholm score, International Knee Documentation Committee score, and Tegner activity score were evaluated and compared. Graft continuity was evaluated using postoperative magnetic resonance imaging (MRI) (32 and 36 patients underwent MRI in the DB and SB + ALL groups at 7.4 ± 3.2 and 7.5 ± 2.9 months after surgery, respectively), and second-look examinations (second-look examination and tibial screw removal were performed concomitantly when patients (1) had tibial screw-related irritation or (2) needed the screws removed, 28 and 23 patients underwent examinations in the DB and SB + ALL groups at 24.0 ± 6.8 and 24.9 ± 8.1 months after surgery, respectively). All measurements were compared between the groups.

RESULTS

Postoperative clinical outcomes significantly improved in both groups. (All variables showed P < .001) No statistically different outcomes were found between the 2 groups. Additionally, postoperative graft continuity on MRI and second-look examinations were not different between the 2 groups.

CONCLUSIONS

The DB and SB + ALL groups showed similar postoperative clinical, radiographic, and second-look arthroscopic outcomes. Both groups showed excellent postoperative stability and clinical outcomes compared with the preoperative measurements.

LEVEL OF EVIDENCE

Level II, randomized controlled trial.

Differences in the microstructural and mechanical qualities of semitendinosus tendon grafts between skeletally immature and mature patients in anterior cruciate ligament reconstruction

BACKGROUND

This study aimed to investigate the microstructural and mechanical properties of semitendinosus tendon graft tissues during anterior cruciate ligament reconstruction and the clinical outcomes in skeletally immature and mature patients.

METHODS

Twenty-two patients who underwent primary anterior cruciate ligament reconstruction using a hamstring tendon graft were analyzed and divided into skeletally immature (n = 7) and mature groups (n = 15) based on magnetic resonance imaging findings of the epiphyseal plate of the distal femur. Tissue samples were collected from the mid-portion of the semitendinosus tendon. The collagen fibril diameter, maximum stress, and strain at maximum stress point in the semitendinosus tendon tissues were calculated for comparison of the microstructural and mechanical properties between the two groups. Postoperative outcomes were also assessed between the two groups.

RESULTS

The mean and 60th and 80th percentiles of fibril diameters in the skeletally immature group were significantly smaller than those in the mature group (65.9 ± 13.0, 73.5 ± 19.3, and 91.3 ± 27.4 nm in the skeletally immature group; and 90.3 ± 14.7, 94.0 ± 18.4, and 125.3 ± 19.9 nm in the skeletally immature group; p = 0.001, 0.024, and 0.004, respectively). Additionally, the strain at maximum stress was higher in the skeletally immature group (237.2 ± 102.4% vs. 121.5 ± 51.9%, p = 0.024). However, there was no difference in maximum stress between the skeletally immature and mature groups (19.9 ± 14.3 MPa vs. 24.5 ± 23.4 MPa, p = 0.578). Strain was negatively correlated with the mean fibril diameter and the 60th and 80th percentiles of fibril diameters, whereas stress was positively correlated with the mean fibril diameter. The skeletally immature group had a higher pivot shift test-positive rate than the mature group at the last follow-up (p = 0.023).

CONCLUSION

Semitendinosus tendon graft tissues differed microstructurally and mechanically between skeletally immature and mature patients.

LEVEL OF EVIDENCE

Level Ⅳ.

Limb Symmetry Index of Single-Leg Vertical Jump vs. Single-Leg Hop for Distance After ACL Reconstruction: A Systematic Review and Meta-analysis

CONTEXT

The limb symmetry index (LSI) is recommended as a milestone of return to play (RTP), and relying on the LSI value of a single-leg hop for distance (SLHD) test may overestimate rehabilitation status. Identifying a more reliable functional test can help to carefully make decisions for RTP.

OBJECTIVE

The aim was to compare the LSI value of the SLHD test with that of a single-leg vertical jump (SLVJ) test after anterior cruciate ligament reconstruction (ACLR) and determine which test provides lower LSI values.

DATA SOURCES

The PubMed, Web of Science, Embase, and Cochrane Library databases were searched from inception to July 2022.

STUDY SELECTION

Observational studies with participants who had both SLHD and SLVJ tests after ACLR and LSI values of an SLHD and SLVJ were included. Disagreements were resolved after discussion between the 2 researchers.

STUDY DESIGN

Systematic review and meta-analysis.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Data on the primary outcomes (LSI values of the SLVJ and SLHD tests) were collected. Means and standard deviations (SDs) for each variable of interest were used to calculate standardized mean differences (SMDs).

RESULTS

A total of 12 studies met the inclusion criteria for the meta-analysis. A total of 587 patients underwent SLHD and SLVJ tests at different time points after ACLR. Compared with the SLHD test, the SLVJ test provided lower LSI values (SMD -0.42; 95% confidence interval (CI) -0.67 to -0.17). Subgroup analysis found that the SLVJ test provided a lower LSI value than the SLHD test in a specific period (approximately 7-18 months after ACLR, SMD -0.53; 95% CI -0.91 to -0.14) and a similar LSI value at other times.

CONCLUSION

The SLVJ test provided lower LSI values in a specific period (7-18 months after ACLR).

Remnant tissue enhances early postoperative biomechanical strength and infiltration of Scleraxis-positive cells within the grafted tendon in a rat anterior cruciate ligament reconstruction model

When ruptured, ligaments and tendons have limited self-repair capacity and rarely heal spontaneously. In the knee, the Anterior Cruciate Ligament (ACL) often ruptures during sports activities, causing functional impairment and requiring surgery using tendon grafts. Patients with insufficient time to recover before resuming sports risk re-injury. To develop more effective treatment, it is necessary to define mechanisms underlying ligament repair. For this, animal models can be useful, but mice are too small to create an ACL reconstruction model. Thus, we developed a transgenic rat model using control elements of Scleraxis (Scx), a transcription factor essential for ligament and tendon development, to drive GFP expression in order to localize Scx-expressing cells. As anticipated, Tg rats exhibited Scx-GFP in ACL during developmental but not adult stages. Interestingly, when we transplanted the flexor digitorum longus (FDP) tendon derived from adult Scx-GFP+ rats into WT adults, Scx-GFP was not expressed in transplanted tendons. However, tendons transplanted from adult WT rats into Scx-GFP rats showed upregulated Scx expression in tendon, suggesting that Scx-GFP+ cells are mobilized from tissues outside the tendon. Importantly, at 4 weeks post-surgery, Scx-GFP-expressing cells were more frequent within the grafted tendon when an ACL remnant was preserved (P group) relative to when it was not (R group) (P vs R groups (both n = 5), p<0.05), and by 6 weeks, biomechanical strength of the transplanted tendon was significantly increased if the remnant was preserved (P vsR groups (both n = 14), p<0.05). Scx-GFP+ cells increased in remnant tissue after surgery, suggesting remnant tissue is a source of Scx+ cells in grafted tendons. We conclude that the novel Scx-GFP Tg rat is useful to monitor emergence of Scx-positive cells, which likely contribute to increased graft strength after ACL reconstruction.

Augmentation of ACL Autograft Reconstruction With an Amnion Collagen Matrix Wrap and Bone Marrow Aspirate Concentrate: A Pilot Randomized Controlled Trial With 2-Year Follow-up

Background

It is theorized that the lack of a synovial lining after anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) contributes to slow ligamentization and possible graft failure. Whether graft maturation and incorporation can be improved with the use of a scaffold requires investigation.

Purpose

To evaluate the safety and efficacy of wrapping an ACL autograft with an amnion collagen matrix and injecting bone marrow aspirate concentrate (BMAC), quantify the cellular content of the BMAC samples, and assess 2-year postoperative patient-reported outcomes.

Study Design

Randomized controlled trial; Level of evidence, 2.

Methods

A total of 40 patients aged 18 to 35 years who were scheduled to undergo ACLR were enrolled in a prospective single-blinded randomized controlled trial with 2 arms based on graft type: bone-patellar tendon-bone (BTB; n = 20) or hamstring (HS; n = 20). Participants in each arm were randomized into a control group who underwent standard ACLR or an intervention group who had their grafts wrapped with an amnion collagen matrix during graft preparation, after which BMAC was injected under the wrap layers after implantation. Postoperative magnetic resonance imaging (MRI) mapping/processing yielded mean T2* relaxation time and graft volume values at 3, 6, 9, and 12 months. Participants completed the Single Assessment Numeric Evaluation Score, Knee injury and Osteoarthritis Outcome Score, and pain visual analog scale. Statistical linear mixed-effects models were used to quantify the effects over time and the differences between the control and intervention groups. Adverse events were also recorded.

Results

No significant differences were found at any time point between the intervention and control groups for BTB T2* (95% CI, -1.89 to 0.63; P = .31), BTB graft volume (95% CI, -606 to 876.1; P = .71), HS T2* (95% CI, -2.17 to 0.39; P = .162), or HS graft volume (95% CI, -11,141.1 to 351.5; P = .28). No significant differences were observed between the intervention and control groups of either graft type on any patient-reported outcome measure. No adverse events were reported after a 2-year follow-up.

Conclusion

In this pilot study, wrapping a graft with an amnion collagen matrix and injecting BMAC appeared safe. MRI T2* values and graft volume of the augmented ACL graft were not significantly different from that of controls, suggesting that the intervention did not result in improved graft maturation.

Registration

NCT03294759 (ClinicalTrials.gov identifier).

Evaluation of biomechanical properties and biocompatibility: are partially absorbable cords eligible for anterior cruciate ligament reconstruction?

Introduction: Independent augmentation technology based on reinforcing devices has been reported to signifi-cantly reduce the elongation behavior of graft and improve knee stability after anterior cruciate ligament reconstruction (ACLR). Using biodegradable devices could reduce the risk of severe inflammatory reactions due to particle accumulation from foreign bodies. Given the limitations of the mechanical properties of biodegradable materials, partially biodegradable composite devices may offer a compromise strategy. Methods: Three types of partially absorbable core-sheath sutures, including low-absorbable cord (LA-C), medium-absorbable cord (MA-C) and high-absorbable cord (HA-C), were braided using unabsorbable ultra-high molecular weight polyethylene (UHMWPE) yarn and absorbable polydioxanone (PDO) monofil-ament bundle based on the desired configuration. The feasibility of these partially absorbable cords were verified by biomechanical testing, material degradation testing, and cell experiments, all performed in vitro. Results: Reinforcement of an 8 mm graft with the cords decreased dynamic elongation by 24%-76%, was positively related to dynamic stiffness, and increased the failure load by 44%-105%, during which LA-C showed maximum enhancement. Human ligament-derived fibroblasts showed good proliferation and vitality on each cord over 2 weeks and aligned themselves in the direction of the fibers, especially the UHMWPE portion. Discussion: This study supports the potential of partially degradable UHMWPE/PDO cords, particularly LA-C, for graft protection. Nervertheless, a higher proportion of biodegradable material results in lower stiffness, which may impair the protective and lead to mechanical instability during degradation.

Preserving the hamstring tendon insertion during ACL reconstruction with an autograft: Systematic literature review

INTRODUCTION

The hamstring tendons (gracilis and semitendinosus) are often used as an autograft for anterior cruciate ligament (ACL) reconstruction. Healing of this graft involves a slow biological process called ligamentization. To encourage this process, some authors have proposed preserving the insertion of the hamstring tendons.

HYPOTHESIS

Leaving the tibial insertion of the hamstring tendons intact will provide better early biological incorporation and superior tibial mechanical fixation resulting in various clinical advantages.

MATERIALS AND METHODS

In January 2022, a systematic literature review was carried out independently by two authors of the Medline, PubMed and Embase databases. The keywords used were "pedicular" or "pedicled" or "preservation of tibial attachment" or "hamstring tibial insertion" AND "ACL reconstruction". Each author's data was analyzed separately.

RESULTS

Sixteen articles were analyzed. Preserving the hamstring tibial insertion during ACL reconstruction improves the graft's biological incorporation during the initial postoperative phase according to clinical studies with MRI analysis and provides a mechanical advantage at the graft's tibial attachment according to biomechanical studies (construct up to 65% stiffer). There was no difference in the clinical and functional scores when compared to the conventional technique in which the hamstring tendons are detached from their tibial insertion.

DISCUSSION

The main conclusion of this systematic literature review was that preserving the hamstring tibial insertion during ACL reconstruction appears to improve the graft's ligamentization with biological and mechanical advantages relative to detaching the hamstring tendons. The clinical and functional results were comparable to other techniques. Prospective studies with large cohorts are still needed to confirm these findings.

LEVEL OF EVIDENCE

IV; Systematic review of literature.

Histopathological Analysis of the Degree of Tendinosis in Failed Anterior Cruciate Ligament Grafts

INTRODUCTION

After reconstruction of the anterior cruciate ligament, the modification processes in the transplanted tendon tissue directly influence the biomechanical properties of the knee. The histopathological alterations in failed grafts have hardly been studied.

OBJECTIVE

Our study focused on examining the presence and extent of tendinosis (low or high grade) in the tendon tissue of failed anterior cruciate ligament reconstructions. We considered its relationship to the type of transplant, the symptoms, the arthroscopic appearance, the mode of trauma, and the timing of the failure.

MATERIALS AND METHODS

The tendon tissue of failed anterior cruciate ligament reconstructions in 30 patients was gathered during revision surgery and its histopathology was analysed for the occurrence of structural alterations. The classification of the tendinosis as low or high grade was semiquantitative based on five qualities. We used a standardised questionnaire to collect patient data and we used the Marburg Arthroscopy Score for the intraoperative evaluation of the graft.

RESULTS

We found histological vitality and, except for two samples, structural alterations consistent with tendinosis, predominantly high grade, in all failed anterior cruciate ligament grafts. No direct link could be proved between the degree of tendinosis and the type of graft used, the symptoms (except for instability) or the timing of the graft failure, the mode of trauma, or the arthroscopic appearance of the failed plasty. However, the accumulation of high-grade tendinosis in patients with hamstring tendons, subjective instability, and graft failure between 1 to 5 years postoperatively was noteworthy.

CONCLUSION

Structural alterations consistent with tendinosis could be detected, with different expressions, in the vital tendon tissue of anterior cruciate ligament reconstructions. This indicates that the graft is subject to repetitive microtrauma. However, it is still unclear how tendinosis influences the failure of anterior cruciate ligament reconstructions.

Anterior Cruciate Ligament Reconstruction with Quadrupled Semitendinosus Graft or Synthetic Ligament: Knee Stability and Clinical Outcomes at Three Years Follow-Up

The incidence of anterior cruciate ligament reconstruction (ACLR) surgeries is increasing and graft choice is important for a rapid return to activity, especially in patients older than 30 years. The aim of this study is to compare in term of quality of life and knee stability of patients who undergone ACLR using quadrupled semitendinosus (ST4) graft against patients who undergone ACLR with synthetic ligaments. Thirty-nine patients undergoing ACLR were enrolled in the study and were divided into two groups: ACLR with synthetic ligaments-LARS (group A) and ACLR with quadrupled semitendinosus graft ST4 (group B). They underwent surgery at Policlinico di Bari Orthopedic Unit between January 2017 and January 2020. Group A was composed by nineteen patients (36.16 ± 4.41 mean age-years, 22.47 ± 2.63 mean BMI-kg/m², 39.37 ± 10.05 mean time evaluation after surgery-months) and group B was composed by twenty patients (34.95 ± 3.59 mean age-years, 21.1 ± 2.88 mean BMI-kg/m², 36.75 ± 8.69 mean time evaluation after surgery-months). For each patient, the following data were recorded: age; side of injury, BMI, date of surgery, anterior knee laxity with the arthrometer, and Lysholm knee scoring scale. Mean value of anterior tibial translation (ATT) in group A was 3.09 mm ± 0.65 and in group B was 2.66 mm ± 1.61 (pvalue of 0.1139). Mann--Whitney U test used to compare the Lysholm means values between groups showed a pvalue of 0.9307. LARS has comparable clinical and functional outcomes compared with hamstring autografts at short-term of 3 years follow-up. Level of Evidence: IV.

Preserving the Semitendinosus Distal Attachment Is Associated With Improved Graft Remodeling After ACL Reconstruction

BACKGROUND

The semitendinosus (ST) tendon can be used by itself as a graft for anterior cruciate ligament (ACL) reconstruction. An increasing number of these procedures are being done while preserving the ST's tibial attachment, but there are no data on the remodeling of an attached ST (aST) graft.

PURPOSE

To compare graft remodeling on magnetic resonance imaging (MRI) scans at 1 year after ACL reconstruction between standard free ST graft and aST graft.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This prospective study enrolled 180 patients who were undergoing ACL reconstruction: 90 with the ST graft and 90 with the aST graft. The analysis was performed 1 year after the surgery. The main endpoint was the signal-to-noise quotient (SNQ) on MRI scans (T1-weighted sequence). The secondary endpoints were tibial tunnel widening (TTW), graft maturation (Howell classification), retear rate, new surgery rate, Simple Knee Value, Lysholm score, International Knee Documentation Committee (IKDC) score, postoperative Tegner score, difference between pre- and postoperative Tegner scores, ACL-Return to Sport after Injury (ACL-RSI), return-to-sports rate, and time to return to sports.

RESULTS

The mean adjusted SNQ was 1.18 (95% CI, 0.72-1.65) in the aST group and 3.88 (95% CI, 3.42-4.34) in the ST group (P < .001). The new surgery rate was 2.2% in the aST group and 10% in the ST group (P = .029). The median Lysholm score was significantly higher in the aST group (99; interquartile range [IQR], 95-100) than in the ST group (95; IQR, 91-99) (P = .004). The mean time to return to sports was significantly shorter in the aST group (248.73 ± 141.62 days) than the ST group (317.23 ± 144.69 days) (P = .002). No statistically significant difference was found between groups in the TTW (P = .503), Howell graft maturity grade (P = .149), retear rate (P > .999), Simple Knee Value (P = .061), postoperative Tegner score (P = .320), pre- to postoperative difference in Tegner score (P = .317), ACL-RSI (P = .097), IKDC score (P = .621), and return-to-sports rate (P > .999).

CONCLUSION

At 1 year postoperatively, remodeling of an ST graft assessed using MRI is better when its distal attachment is left intact.

Factors Affecting Graft Remodeling and Anterior Cruciate Ligament Reconstruction: MRI Study of 180 Knees

BACKGROUND

Several factors affect the retear rate after anterior cruciate ligament (ACL) reconstruction, but there are few data on which factors affect graft remodeling.

PURPOSE

To determine which factors are associated with the remodeling of an ACL graft.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A retrospective longitudinal study was conducted to investigate the relationship between various exposure factors and the occurrence of an "event": graft remodeling measured with the signal-to-noise quotient (SNQ). Data were collected prospectively and analyzed retrospectively for this study. The endpoint was the SNQ on magnetic resonance imaging at postoperative 1 year. The effect of the following parameters on SNQ was investigated: sex, smoking habits, age at surgery, body mass index, time to surgery, time to return to sports, type of sport (in-line, pivot, contact), type of graft (free semitendinosus [ST] or attached ST), and addition of lateral tenodesis.

RESULTS

An overall 180 patients were enrolled (90 with each technique). The following factors were significantly and independently associated with the SNQ: attached ST graft (β = -2.624668; P < .001), age at the time of surgery (β = -0.7948476; P = .012), and time elapsed between the injury event and surgery (β = -0.7137424; P = .046).

CONCLUSION

Leaving the ST graft attached distally, being older at the time of surgery, and having more time elapse between the injury event and ACL reconstruction surgery were significantly associated with better graft remodeling.

Comparison of Primary Repair of the Anterior Cruciate Ligament and Anterolateral Structures to Reconstruction and Lateral Extra-articular Tenodesis at 2-Year Follow-up

BACKGROUND

Lateral extra-articular procedures have been effective in reducing graft rupture rates after anterior cruciate ligament (ACL) reconstruction (ACLR), but the evidence supporting their role in ACL repair is sparse.

PURPOSE/HYPOTHESIS

The purpose was to compare clinical and radiological outcomes of ACLR and lateral extra-articular tenodesis (LET) (ACLR+LET) against combined repair of the ACL and anterolateral (AL) structures (ACL+AL Repair). It was hypothesized that patients undergoing ACL+AL Repair would have noninferior clinical and radiological outcomes with respect to International Knee Documentation Committee (IKDC) scores, knee laxity parameters, and magnetic resonance imaging (MRI) characteristics. Furthermore, it was hypothesized that patients undergoing repair would have significantly better Forgotten Joint Score-12 (FJS-12) values and shorter times to return to the preinjury level of sport, without any increase in the rate of ipsilateral second ACL injury.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Consecutive patients evaluated with an acute ACL tear were considered for study eligibility. ACLR+LET was only performed when intraoperative tear characteristics contraindicated ACL repair. Patient-reported outcome measures such as the IKDC score, Lysholm score, and Knee injury and Osteoarthritis Outcome Score (KOOS); reinjury rates; anteroposterior side-to-side laxity difference; and MRI characteristics were reported at a minimum follow-up of 2 years. The noninferiority study was based on the IKDC subjective score; side-to-side anteroposterior laxity difference; and signal-to-noise quotient (SNQ). The noninferiority margins were defined using the existing literature. An a priori sample size calculation was performed using the IKDC subjective score as the primary outcome measure.

RESULTS

A total of 100 patients (47 ACLR+LET, 53 ACL+AL Repair) with a mean follow-up of 25.2 months (range, 24-31 months) were enrolled and underwent surgery within 15 days of injury. At the final follow-up, the differences between groups with respect to the IKDC score, anteroposterior side-to-side laxity difference, and SNQ did not exceed noninferiority thresholds. ACL+AL Repair was associated with a shorter time to return to the preinjury level of sport (ACL+AL Repair: mean, 6.4 months; ACLR+LET: mean, 9.5 months; P < .01), better FJS-12 values (ACL+AL Repair: mean, 91.4; ACLR+LET: mean, 97.4; P = .04), and a higher proportion of patients achieving the Patient Acceptable Symptom State (PASS) for the KOOS subdomains studied (Symptoms: 90.2% vs 67.4%, P = .005; Sport and Recreation: 94.1% vs 67.4%, P < .001; Quality of Life: 92.2% vs 73.9%, P = .01). There were no significant differences between groups with respect to ipsilateral second ACL injury rates (ACL+AL Repair group, 3.8% and ACLR+LET group, 2.1% [n = 1]; P = .63).

CONCLUSION

ACL+AL Repair yielded clinical outcomes that were noninferior to (or not significantly different from) ACLR+LET with respect to IKDC subjective, Tegner activity level, and Lysholm scores; knee laxity parameters; graft maturity; and rates of failure and reoperation. However, there were significant advantages of ACL+AL Repair, including a shorter duration of time to return to the preinjury level of sport, better FJS-12 values, and a higher proportion of patients achieving PASS for KOOS subdomains studied (Symptoms, Sport and Recreation, Quality of Life).

Graft Selection Between Tendon Autograft and Allograft in Anterior Cruciate Ligament Reconstruction Based on the Histological Perspective: A Meta-Analysis

Objective:  The purpose of this meta-analysis is to compare ligament healing on autograft and allograft in anterior cruciate ligament (ACL) reconstruction. Methods:  The selection of appropriate studies was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We made a statistical analysis using a review manager. Electronic reports were searched using the PubMed, Medline, and Cochrane Library databases. The inclusion criteria were animal studies and cellular histology of both grafts as an outcome. Results:  The initial search revealed 412 potential articles. After duplicates were removed, 246 articles remained. Then, 14 articles were obtained and screened for relevance and eligibility. The relevant articles were searched manually, checking for eligibility and details in order not to miss included reports. Subsequently, 5 studies were included, with a total of 232 samples, reporting the biopsied results with quantitative histology of ligament healing between allograft and autograft. The biopsy samples in those studies were examined under light or electron microscope, to analyze the cellular distribution area and ligamentization stages in each group. Meta-analyses found significant difference between autograft and allograft (Heterogeneity, I2 = 89%; Mean Difference, 95% confidence interval [CI] = -34.92, -54.90, -14.93; p  = 0.0006). There is also a significant difference on both graft in cellular count at over 24 weeks (Heterogeneity, I2 = 26%; Mean Difference, 95% CI = -14.59, -16.24, -12.94; p  < 0.00001). Conclusion:  In the current meta-analysis, autograft shows a significant difference when compared to allograft, with more cellular accumulation and faster remodeling response on the ligamentization process being noticed in the former. However, a larger clinical trial will be needed to emphasize this literature's result.

Neuromuscular activity of the lower-extremities during running, landing and changing-of-direction movements in individuals with anterior cruciate ligament reconstruction: a review of electromyographic studies

PURPOSE

Running, jumping/landing and cutting/change of direction (CoD) are critical components of return to sport (RTS) following anterior cruciate ligament reconstruction (ACLR), however the electromyographic (EMG) activity patterns of the operated leg during the execution of these tasks are not clear.

METHODS

A systematic review was conducted to retrieve EMG studies during running, jumping/landing and cutting/(CoD) in ACLR patients. MEDLINE, PubMed, SPORTDiscus and Web of Science databases were searched from 2000 to May, 2022 using a combination of keywords and their variations: "anterior cruciate ligament reconstruction" OR "ACLR", "electromyography" OR "EMG", "running", "jumping" OR "landing", "cutting" OR "change-of-direction" OR "CoD". The search identified studies comparing EMG data during running, landing and cutting/(CoD) between the involved limb and contralateral or control limbs. Risk of bias was assessed and quantitative analyses using effect sizes were performed.

RESULTS

Thirty two studies met the inclusion criteria. Seventy five percent (24/32) of the studies reported altered EMG activity pattern of the ACLR leg during running, jumping/landing and cutting/(CoD) when compared with either the healthy control leg or the contra-lateral leg. Twelve studies showed decreased, delayed or earlier onset and delayed peak in quadriceps EMG activity with small to large effect sizes and 9 studies showed increased, delayed or earlier onset and delayed peak in hamstrings EMG activity with small to large effect sizes. Four studies showed a "hamstrings-dominant" strategy i.e. decreased quadriceps coupled with increased hamstrings EMG activity in both running and jumping/landing irrespective of graft type. One study reported that on the grounds of decreased quadriceps activity, lower hamstrings EMG activity was predictive of ipsilateral re-injury in ACLR patients.

CONCLUSION

This systematic review of Level III evidence showed that the ACLR leg displays decreased quadriceps or increased hamstrings EMG activity or both despite RTS. Simultaneous decreased quadriceps and increased hamstrings EMG activity was shown for both running and jumping/landing. From a clinical perspective this "hamstrings dominant" strategy can serve as a protective mechanism against graft re-injury.

LEVEL OF EVIDENCE

III.

Characterizing the viscoelastic properties of the anterolateral ligament and grafts commonly used in its reconstruction

BACKGROUND

Current anatomic anterolateral ligament reconstruction is typically performed using either a gracilis tendon or an iliotibial band graft based on their quasi-static behavior. However, there is limited knowledge about their viscoelastic behaviors. This study aimed to characterize the viscoelastic properties of the anterolateral ligament, distal iliotibial band, distal gracilis tendon and proximal gracilis tendon for graft material choice in anterolateral ligament reconstruction.

METHODS

All the tissues were harvested from thirteen fresh-frozen cadaveric knees and subjected to preconditioning (3-6 MPa), sinusoidal cycle (1.2-12 MPa), dwell at constant load (12 MPa), and load to failure (3%/s). The quasi-static and viscoelastic properties of the soft tissues were computed and compared using a linear mixed model (p < 0.05).

FINDINGS

The hysteresis of anterolateral ligament (mean:0.4 Nm) was comparable with gracilis halves (p > 0.85) but iliotibial band (6 Nm) was significantly higher (p < 0.001,ES = 6.5). In contrast, the dynamic creep of anterolateral ligament (0.5 mm) was similar to iliotibial band (0.7 mm, p > 0.82) whereas both gracilis halves were significantly lower (p < 0.007,ES > 1.4). The elastic modulus of anterolateral ligament (181.4 MPa, p < 0.001,ES > 2.1) was the lowest compared to the grafts materials (distal gracilis tendon:835 MPa, distal gracilis tendon:726 MPa, iliotibial band:910 MPa). Additionally, the failure load of the anterolateral ligament (124.5 N, p < 0.001,ES > 2.9) was also the lowest.

INTERPRETATION

The mechanical properties of the gracilis halves and iliotibial band were significantly different from anterolateral ligament, except for hysteresis and dynamic creep, respectively. Our findings showed that the gracilis halves may be a more appropriate graft choice for anterolateral ligament reconstruction due to its low energy dissipation and permanent deformation under dynamic loads.

Clinical Research Progress of Internal Brace Ligament Augmentation Technique in Knee Ligament Injury Repair and Reconstruction: A Narrative Review

Knee ligament injuries are most common in sports injuries. In general, ligament repair or reconstruction is necessary to restore the stability of the knee joint and prevent secondary injuries. Despite advances in ligament repair and reconstruction techniques, a number of patients still experience re-rupture of the graft and suboptimal recovery of motor function. Since Dr. Mackay's introduction of the internal brace technique, there has been continuous research in recent years using the internal brace ligament augmentation technique for knee ligament repair or reconstruction, particularly in the repair or reconstruction of the anterior cruciate ligament. This technique focuses on increasing the strength of autologous or allograft tendon grafts through the use of braided ultra-high-molecular-weight polyethylene suture tapes to facilitate postoperative rehabilitation and avoid re-rupture or failure. The purpose of this review is to present detailed research progress in the internal brace ligament enhancement technique of knee ligament injury repair as well as the reconstruction from biomechanical and histological research and clinical studies and to comprehensively assess the value of the application of this technique.

Anterior Cruciate Ligament Reconstruction Using a 4-Strand Semitendinosus Tendon Graft or a Doubled Semitendinosus and Gracilis Tendon Graft: A 4.5-Year Prospective, Randomized, Double-Blind, Parallel-Group Study

BACKGROUND

Hamstring tendon grafts are the most common choice for anterior cruciate ligament (ACL) reconstruction (ACLR). Previous studies have provided evidence that offers conflicting opinions concerning the most favorable graft choice.

PURPOSE

To identify whether the use of a quadrupled semitendinosus tendon (ST) or doubled semitendinosus tendon and gracilis tendon (ST/G) graft provides comparable anterior tibial translation (ATT) with similar functional results and similar donor site morbidity.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

This was a prospective, patient- and surgeon-blinded, randomized trial set in a busy orthopaedic and traumatology department at a university hospital. Between 2015 and 2017, a total of 162 patients with ACL lesions were randomized to undergo ACLR with either a quadrupled ST or doubled ST/G graft. The primary endpoint was ATT assessed with the KT-1000 arthrometer. Clinical outcomes were assessed using the patient-reported outcome measures (PROMs) of the visual analog scale (VAS), International Knee Documentation Committee (IKDC) subjective evaluation form, Knee injury and Osteoarthritis Outcome Score (KOOS), Tegner activity scale, and Lysholm knee scoring scale.

RESULTS

Preoperative demographic data, ATT, and PROM scores showed no significant differences. At 4.5 years, no significant differences were found between the ST and ST/G groups with respect to PROM scores and KT-1000 arthrometer, Lachman test, and pivot-shift test findings. Differences in functional results between groups were significant (muscle strength). Subgroup analysis revealed significantly increased ATT in female patients undergoing ACLR with a quadrupled ST graft during the 4.5-year observation period, as assessed by the KT-1000 arthrometer, as well as inferior KOOS, IKDC, Lysholm, and VAS scores.

CONCLUSION

This study showed a significant increase in ATT as well as inferior results on PROMs during a 4.5-year observation period in female patients undergoing ACLR with a quadrupled ST graft. In male patients, the study provided evidence of the noninferiority of ACLR with an ST graft, with no influence on donor site morbidity.

TRIAL REGISTRATION

clinicaltrials.gov: NCT03626883.

Scapholunate instability: why are the surgical outcomes still so far from ideal?

The wrist is a universal joint with intrinsic and extrinsic ligaments that function and fail as ligamentous complexes. Those related to scapholunate instability (SLI) include the dorsal scapholunate complex (DSLC), volar radiolunate complex and scaphotrapeziotrapezoid complex. Together the DSLC, scaphoid and lunate create an 'acetabulum' for the capitate, with the dorsal intercarpal ligament being a labrum to contain the capitate. SLI results from failure of the DSLC, typically from its scaphoid attachments. Failure of the lunate and or triquetral attachments increases the instability. DSLC failure leads to radioscaphoid instability, which is the symptomatic clinical problem. SLI reconstruction with open surgery and trans-osseous tendon graft techniques have been challenging. We discuss a biological arthroscopic approach to identify, mobilize and debride the disrupted DSLC. This ligament/capsular/periosteum sheet is then advanced and secured to the debrided footprint. Thereby reconstituting the acetabulum, labrum and scaphoid stability.

Return to Sport After Anterior Cruciate Ligament Reconstruction Requires Evaluation of >2 Functional Tests, Psychological Readiness, Quadriceps/Hamstring Strength, and Time After Surgery of 8 Months

PURPOSE

The purpose of this study was to examine the factors commonly used to determine readiness for return to sport (RTS) in the ACL reconstruction (ACL-R) patient population and assess which were most influential to successfully returning to sport and avoiding re-tear.

METHODS

The PUBMED, EMBASE and Cochrane Library databases were queried for studies related to RTS in ACL-R. Inclusion and exclusion criteria were applied to identify studies with greater than 1-year outcomes detailing the rate of return and re-tear given a described RTS protocol. Data of interest were extracted, and studies were stratified based on level of evidence and selected study features. Meta-analysis or subjective synthesis of appropriate studies was used to assess more than 25 potentially significant variables effecting RTS and re-tear.

RESULTS

After initial search of 1503 studies, 47 articles were selected for inclusion in the final data analysis, including a total of 1432 patients (31.4% female, 68.6% male). A meta-analysis of re-tear rate for included Level of Evidence 1 studies was calculated to be 2.8%. Subgroups including protocols containing a strict time until RTS, strength testing, and ≥2 dynamic tests demonstrated decreased RTS and re-tear heterogeneity from the larger group. Time to RTS, strength testing, dynamic functional testing, and knee stability were also found to be among the most prevalent reported criteria in RTS protocol studies.

CONCLUSIONS

This study suggests a multifactorial clinical algorithm for successful evaluation of RTS. The "critical criteria" recommended by the authors to be part of the postoperative RTS criteria include time since surgery of 8 months, use of >2 functional tests, psychological readiness testing, and quadriceps/hamstring strength testing in addition to the modifying patient factors of age and female gender.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I-IV studies.

Impact of Occupation on 12-Month Outcomes After Anterior Cruciate Ligament Reconstruction in Male Patients

Background

The impact of a physically demanding occupation on clinical outcomes after anterior cruciate ligament (ACL) reconstruction (ACLR) is largely unknown.

Purpose/Hypothesis

The purpose of this study was to assess the influence of occupation on 12-month outcomes after ACLR in male patients. It was hypothesized that patients undertaking manual work would not only have better functional outcomes in terms of strength and range of motion but also higher rates of joint effusion and greater anterior knee laxity.

Study Design

Cohort study; Level of evidence, 3.

Methods

From an initial cohort of 1829 patients, we identified 372 eligible patients aged 18 to 30 years who underwent primary ACLR between 2014 and 2017. Based on a preoperative self-assessment, 2 groups were established: patients engaged in heavy manual occupations and those engaged in low-impact occupations. Data were collected from a prospective database including effusion, knee range of motion (using side-to-side difference), anterior knee laxity, limb symmetry index for single hop and triple hop, International Knee Documentation Committee (IKDC) subjective score, and complications up to 12 months. Because of the significantly lower rate of female patients undertaking heavy manual occupations compared to low-impact occupations (12.5% and 40.0%, respectively), data analysis was focused on male patients. Outcome variables were assessed for normality, and statistical comparisons were made between the heavy manual and low-impact groups using either an independent-samples t test or the Mann-Whitney U test.

Results

Of 230 male patients, 98 were included in the heavy manual occupation group, and 132 were included in the low-impact occupation group. Patients in the heavy manual occupation group were significantly younger than those in the low-impact occupation group (mean age, 24.1 vs 25.9 years, respectively; P < .005). There was a greater range of active and passive knee flexion in the heavy manual occupation group than in the low-impact occupation group (mean active, 3.38° vs 5.33°, respectively [P = .021]; mean passive, 2.76° vs 5.00°, respectively [P = .005]). There was no difference in effusion, anterior knee laxity, limb symmetry index, IKDC score, return-to-sport rate, or graft rupture rate at 12 months.

Conclusion

At 12 months after primary ACLR, male patients engaged in heavy manual occupations had a greater range of knee flexion, with no difference in the effusion rate or anterior knee laxity, compared with those engaged in low-impact occupations.

Adaptation of the Signal Noise Quotient MRI classification for graft ligamentization analysis following ATFL and CFL anatomical reconstruction: Validation of the SNQA

BACKGROUND

Chronic ankle instability is the most frequent clinical sign of an antero tibiofibular (ATFL) and/or calcaneo fibular ligament (CFL) tear. One common surgical technique is to use the distal tendon of the gracilis muscle to reconstruct both the ATFL and CFL. In the knee, the hamstring tendons used in anterior cruciate ligament (ACL) reconstruction may go through structural modifications called "ligamentization ". A noninvasive MRI technique has been developed using the Signal/Noise Quotient to compare the signal of the graft following reconstruction to that of the posterior cruciate ligament. To our knowledge no studies have ever evaluated radiographic changes in the graft over time. The main goal of this study was to develop a specific MRI protocol to evaluate graft remodeling following ATFL and CFL reconstruction over time.

METHODS

A prospective study of the changes in the MRI signal of the ATFL-CFL graft 3-months postoperatively was performed in 20 patients. The main outcome was a comparison of the graft signal to that of the peroneal fibular tendon and the surrounding noise to determine the Ankle SNQ (SNQA). MRI images were evaluated by two senior radiologists to assess inter-rater reliability and then 2 weeks later for the intra-rater reproducibility.

RESULTS

The intraclass correlation (ICC) showed excellent inter- and intra rater reliability for the ATFL SNQA (0.96 and 0.91, respectively); and for the CFL SNQA, the ICC was 0.97 and 0.99, respectively. Bland-Altman analysis showed very limited bias in the interpretation of SNQA.

CONCLUSION

This preliminary study confirmed the inter- and intra- rater reliability of a new tool using the SNQA.

Radial Extracorporeal Shock Wave Therapy Enhances Graft Maturation at 2-Year Follow-up After ACL Reconstruction: A Randomized Controlled Trial

Background

Graft maturation is an important prognostic factor for hamstring autograft anterior cruciate ligament reconstruction (ACLR). It remains unclear whether extracorporeal shock wave therapy (ESWT) can promote graft healing after ACLR.

Purpose

To evaluate the therapeutic and graft maturation effects of ESWT in hamstring autograft ACLR.

Study Design

Randomized controlled trial; Level of evidence, 1.

Methods

Between May 18, 2019, and September 20, 2019, we randomly assigned 30 patients who met study inclusion criteria to 2 groups. Patients in the control group followed a 5-week advanced rehabilitation training program (30 minutes/session, 5 times/week) starting at 3 months postoperatively. In the ESWT group, together with the 5-week advanced rehabilitation training, radial ESWT was applied once a week for 5 weeks. Functional scores (Lysholm, International Knee Documentation Committee, and Tegner scores), KT-1000 arthrometer knee laxity measurement, and magnetic resonance imaging scans were assessed at 3 months (baseline), 6 months, and 24 months postoperatively. To evaluate graft maturation, we assessed the graft signal-to-noise quotients (SNQs) of the tibial, intra-articular, and femoral sides on magnetic resonance imaging scans. Data were compared between the ESWT and control groups.

Results

In total, 26 patients (13 with ESWT, 13 controls) were assessed. There were no significant between-group differences on any assessment at baseline, and no significant within-group or between-group differences were found in knee laxity at any point. At 24-month follow-up, the ESWT group had significantly higher Lysholm and Tegner scores compared with the controls (P = .012 and .017, respectively). Regarding graft maturation, at 6-month follow-up, the SNQ of the tibial intraosseous graft was significantly lower in the ESWT group versus controls (P = .006), but no differences were detected at the femoral intraosseous graft (P = .321) or the intra-articular graft (P = .314). At 24-month follow-up, the SNQs of the femoral intraosseous graft and intra-articular graft were significantly lower in the ESWT group versus controls (P = .020 and .044, respectively) but no difference was found at the tibial intraosseous graft (P = .579).

Conclusion

Both enhanced graft maturation and improved functional scores at 24-month follow-up were seen in patients who received radial ESWT during rehabilitation after hamstring autograft ACLR.

Registration

ChiCTR1900022853 (Chinese Clinical Trial Registry).

Canine ACL reconstruction with an injectable hydroxyapatite/collagen paste for accelerated healing of tendon-bone interface

Healing of an anterior cruciate ligament (ACL) autologous graft in a bone tunnel occurs through the formation of fibrovascular scar tissue, which is structurally and compositionally inferior to normal fibrocartilaginous insertion and thus may increase the reconstruction failure and the rate of failure recurrence. In this study, an injectable hydroxyapatite/type I collagen (HAp/Col Ⅰ) paste was developed to construct a suitable local microenvironment to accelerate the healing of bone-tendon interface. Physicochemical characterization demonstrated that the HAp/Col Ⅰ paste was injectable, uniform and stable. The in vitro cell culture illustrated that the paste could promote MC3T3-E1 cells proliferation and osteogenic expression. The results of a canine ACL reconstruction study showed that the reconstructive ACL had similar texture and color as the native ACL. The average width of the tunnel, total bone volume, bone volume/tissue volume and trabecular number acquired from micro-CT analysis suggested that the healing of tendon-bone interface in experimental group was better than that in control group. The biomechanical test showed the maximal loads in experimental group achieved approximately half of native ACL's maximal load at 24 weeks. According to histological examination, Sharpey fibers could be observed as early as 12 weeks postoperatively while a typical four-layer transitional structure of insertion site was regenerated at 48 weeks in the experimental group. The injectable HAp/Col Ⅰ paste provided a biomimetic scaffold and microenvironment for early cell attachment and proliferation, further osteogenic expression and extracellular matrix deposition, and in vivo structural and functional regeneration of the tendon-bone interface.

•

A stable and injectable HAp/Col I paste was designed, optimized and characterized.

•

The paste was applied in ACL reconstruction with an established standard operation procedure.

•

Provided the safety and efficacy evidence for ACL reconstruction, and healing of tendon-bone interface was accelerated.

Loaded open-kinetic-chain exercises stretch the anterior cruciate ligament more than closed-kinetic-chain exercises: In-vivo assessment of anterior cruciate ligament length change

BACKGROUND

Usage of open-kinetic-chain (OKC) or closed-kinetic-chain (CKC) exercises during rehabilitation planning after anterior cruciate ligament (ACL) reconstruction has been debated for decades. However, the ACL elongation pattern during different rehabilitation exercises at different loadings remains unclear.

OBJECTIVES

This study aimed to determine the effects of OKC and CKC exercises on the length of ACL anteromedial bundle (AMB) and posterolateral bundle (PLB) to provide biomechanical support for making rehabilitation schedules.

DESIGN

Laboratory Descriptive Study.

METHOD

Eighteen healthy volunteers were asked to perform two OKC motions, including non-weight-bearing and 10 kg loaded seated knee extension (OKC-0, OKC-10), as well as two CKC motions, including box squat (BS) and deep single-legged lunge (Lunge). Techniques of 2D-to-3D image registration and 3D ligament simulation were used to quantify length changes of ACL.

RESULTS

The motion which led to the least and most ACL elongation were OKC-0 and OKC-10, respectively. The AMB and PLB were significantly longer in OKC-10 than those in OKC-0 during 0-60° and 0-55° of knee flexion (p < 0.01). Compared with reference length, the AMB and PLB were stretched during 0-30° and 0-10° respectively during OKC-10. During CKC exercises, the AMB and PLB were also stretched from 0 to 25°and 0-5°, respectively. Additionally, no significant difference was found in the length change of ACL bundles between BS and lunge.

CONCLUSIONS

OKC-0 may be safe for the rehabilitation program after ACL reconstruction, and loaded exercises shall be applied when restricted with >30° in early-stage rehabilitation.

Anterior cruciate ligament remnant preservation attenuates apoptosis and enhances the regeneration of hamstring tendon graft

AIMS

The effects of remnant preservation on the anterior cruciate ligament (ACL) and its relationship with the tendon graft remain unclear. We hypothesized that the co-culture of remnant cells and bone marrow stromal cells (BMSCs) decreases apoptosis and enhances the activity of the hamstring tendons and tenocytes, thus aiding ACL reconstruction.

METHODS

The ACL remnant, bone marrow, and hamstring tendons were surgically harvested from rabbits. The apoptosis rate, cell proliferation, and expression of types I and III collagen, transforming growth factor-β (TGF-β), vascular endothelial growth factor (VEGF), and tenogenic genes (scleraxis (SCX), tenascin C (TNC), and tenomodulin (TNMD)) of the hamstring tendons were compared between the co-culture medium (ACL remnant cells (ACLRCs) and BMSCs co-culture) and control medium (BMSCs-only culture). We also evaluated the apoptosis, cell proliferation, migration, and gene expression of hamstring tenocytes with exposure to co-culture and control media.

RESULTS

Compared to BMSCs-only culture medium, the co-culture medium showed substantially decreased early and late apoptosis rates, attenuation of intrinsic and extrinsic apoptotic pathways, and enhanced proliferation of the hamstring tendons and tenocytes. In addition, the expression of collagen synthesis, TGF-β, VEGF, and tenogenic genes in the hamstring tendons and tenocytes significantly increased in the co-culture medium compared to that in the control medium.

CONCLUSION

In the presence of ACLRCs and BMSCs, the hamstring tendons and tenocytes significantly attenuated apoptosis and enhanced the expression of collagen synthesis, TGF-β, VEGF, and tenogenic genes. This in vitro study suggests that the ACLRCs mixed with BMSCs could aid regeneration of the hamstring tendon graft during ACL reconstruction.Cite this article: Bone Joint Res 2023;12(1):9-21.

Suture tape augmentation, a novel application of synthetic materials in anterior cruciate ligament reconstruction: A systematic review

Objective: Suture tape (ST) is a common synthetic material in the repairing surgery of soft tissue. Recently, ST augmentation (STA) technique has been described as a novel way to improve the mechanical property of grafts in the anterior cruciate ligament (ACL) reconstruction (ACLR). However, the clinical outcomes of ACLR using ST-augmented grafts have not been clarified. This systematic review aimed to summarize the specific technique of STA and evaluate the clinical outcomes after ACLR with STA. Methods: A electronic search of PubMed and Embase databases with a manual search of Google Scholar was performed to identify studies that reported the clinical outcomes of ACLR with STA. Each included study was abstracted regarding the study features, patient data, surgical information, and outcome measures. Results: Nine studies were included, representing 314 knees in 314 patients undergoing ACLR with STA. Technically, ST was fixed independently from grafts in six studies and along with grafts in two studies. Most studies applied an equal or slightly less tension on ST than ACL graft. Clinically, significant improvements were found in the Lysholm, IKDC, and KOOS scores after a mean follow-up of 16.7 months. Physical examinations of 220 patients showed significant restoration of knee stability at the final follow-up. 59 of 80 (73.8%) patients returned to preinjury sports level at a minimum 2 year follow-up. Six of 266 (2.3%) patients had a graft failure during the first 2 years postoperatively. The use of ST was significantly associated with better Tegner scores and a trend toward significantly higher rates of return to sport compared to standard ACLR. No significant difference was found in most subjective scores, knee laxity, and graft failures between ACLR with or without STA. Conclusion: ACLR with STA achieved overall favorable clinical outcomes. Patients using ST-augmented grafts were seemingly associated with better sports performance compared to standard ACLR. But ACLR with STA was not superior to ACLR alone in most functional scores, knee stability measures, and graft failure rates. A tension equal to or slightly less than the ACL graft should be carefully applied on ST during fixation to avoid stress shielding of the graft.

Influence of platelet-rich plasma (PRP) analogues on healing and clinical outcomes following anterior cruciate ligament (ACL) reconstructive surgery: a systematic review

PURPOSE

To systematically review the effect of PRP on healing (vascularization, inflammation and ligamentization) and clinical outcomes (pain, knee function and stability) in patients undergoing ACL reconstruction and compare the preparation and application of PRP.

METHODS

Independent systematic searches of online databases (Medline, Embase and Web of Science) were conducted following PRISMA guidelines (final search 10th July 2021). Studies were screened against inclusion criteria and risk of bias assessed using Critical appraisal skills programme (CASP) Randomised controlled trial (RCT) checklist. Independent data extraction preceded narrative analysis.

RESULTS

13 RCTs were included. The methods of PRP collection and application were varied. Significant early increases in rate of ligamentization and vascularisation were observed alongside early decreases in inflammation. No significant results were achieved in the later stages of the healing process. Significantly improved pain and knee function was found but no consensus reached.

CONCLUSIONS

PRP influences healing through early vascularisation, culminating in higher rates of ligamentization. Long-term effects were not demonstrated suggesting the influence of PRP is limited. No consensus was reached on the impact of PRP on pain, knee stability and resultant knee function, providing avenues for further research. Subsequent investigations could incorporate multiple doses over time, more frequent observation and comparisons of different forms of PRP. The lack of standardisation of PRP collection and application techniques makes comparison difficult. Due to considerable heterogeneity, (I² > 50%), a formal meta-analysis was not possible highlighting the need for further high quality RCTs to assess the effectiveness of PRP. The biasing towards young males highlights the need for a more diverse range of participants to make the study more applicable to the general population.

TRAIL REGISTRATION

CRD42021242078CRD, 15th March 2021, retrospectively registered.

High initial graft tension is a post-operative risk factor for high UTE T2* value of the graft 6 months after anterior cruciate ligament reconstruction

BACKGROUND

To evaluate the risk factor of "ligamentization" using the ultrashort echo time (UTE)-T2* imaging.

METHODS

Fifty-nine patients (23 males and 36 females, age of 21.9 ± 10.6 years old) who underwent anterior cruciate ligament (ACL) reconstruction with hamstring tendon were evaluated. The UTE T2* values of the reconstructed ACL at 6 months postoperatively were calculated. Circular regions of interest (5-10 mm²) were set at the proximal, mid-substance, and distal regions of the reconstructed ACL. The UTE T2* values of the entire reconstructed ACL were calculated as the average of these three points. Patients were divided into high (27 knees) and low (32 knees) UTE T2* groups by calculating whether their UTE T2* values were greater than the median of the UTE T2* values of all patients. Risk factors for high UTE T2* values were evaluated. Clinical outcomes were compared between the two groups.

RESULTS

There were no significant differences in any measured parameters and clinical outcomes between the two UTE T2* groups. Logistic regression analysis revealed that graft tension was a significant risk factor for patients with high UTE-T2* values (P = 0.047, odds ratio [OR] = 2.285). The UTE-T2* values of the 20 N graft tension using the Tension loc system were significantly lower than those of the 40 N using double-spike plate (DSP) with screws at each site and the 30 N using the Tension loc system at the distal site.

CONCLUSIONS

Higher graft tension was an independent risk factor for high UTE T2* values of the reconstructed ACL.

Graft Intra-Articular Remodeling and Bone Incorporation in ACL Reconstruction: The State of the Art and Clinical Implications

The knee is one of the most frequently affected joints in sports trauma, and anterior cruciate ligament (ACL) injury and meniscal tears are the most common lesions. ACL reconstruction (ACLR) remains the treatment of choice for patients willing to return to their previous activity. There are different surgical techniques and different possible usable grafts. The graft used for ACLR surgery undergoes a bone incorporation process and an intra-articular remodelling named ligamentization until it reaches characteristics similar to the native ligament. After the first incorporation stage, the remodelling process is divided into an early stage that could last 4 weeks, a proliferative stage that lasts 4 to 12 weeks, and a final stage of ligamentization that could last over 1 year. The period of return to sport (RTS) after ACLR, which is becoming shorter and shorter, can be a high-risk period for athletes due to the risk of graft failure. This systematic review aims to define the phases of the ligamentization process considering graft type and fixation techniques, as well as the graft's anatomopathological and biomechanical characteristics, to evaluate a criterion-based rehab progression and maximize patient outcomes for an RTS respecting graft biology. The rehabilitative program has to promote and optimize the graft remodelling and incorporation processes; moreover, it has to accommodate physiological graft healing and avoid overloading. An early RTS and noncompliance with the biological characteristics of the graft in the various phases are associated with a high incidence of re-injury.

Rehabilitation And Advances In Surgical Reconstruction For Anterior Cruciate Ligament Insufficiency: What Has Changed Since The 1960s? - State Of The Art

Anterior cruciate ligament (ACL) insufficiency can be disabling, given the physical and sports activity constraints that negatively impact the quality of life. Consequently, surgery is the main approach for most active patients. Nonetheless, ACL reconstruction (ACLR) cannot be successful without adequate preoperative and postoperative rehabilitation. Since the 1960s, post-ACLR rehabilitation has evolved, mainly from advances in surgery, coupled with a better understanding of the biological concepts of graft revascularization, maturation and integration, which have impacted ACL postoperative rehabilitation protocols. However, new technologies do involve a definite learning curve which could affect rehabilitation programs and produce inconsistent results. The development of rehabilitation protocols cannot be defined without an accurate diagnosis of ACL injury and considering the patient's main physical demands and expectations. This article discusses how postoperative rehabilitation following ACLR has changed from the 1960s to now, focussing on surgical technique (type of tendon graft, fixation devices, and graft tensioning), biological concepts (graft maturation and integration), rehabilitation protocols (prevention of ACL injuries, preoperative rehabilitation, postoperative rehabilitation), criteria to return to sports, patient's reported outcomes and outcome. Although rehabilitation plays an essential role in managing ACL injuries, it cannot be fully standardised preoperatively or postoperatively. Preoperative and postoperative rehabilitation should be based on an accurate clinical diagnosis, patients' understanding of their injury, graft tissue biology and biomechanics, surgical technique, the patient's physical demands and expectations, geographical differences in ACL rehabilitation and future perspectives.

Association of Smoking With Graft Rupture After Anterior Cruciate Ligament Reconstruction

Background

The effect of smoking on graft rupture after anterior cruciate ligament (ACL) reconstruction is not well understood.

Hypothesis

It was hypothesized that there will be no relationship between tobacco use and graft rupture after ACL reconstruction, as reflected by postoperative magnetic resonance imaging (MRI) and arthroscopic examination.

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 233 patients who received primary ACL reconstruction with hamstring tendon autograft between January 1, 2013, and December 31, 2019, and who underwent MRI evaluation at 20.2 ± 1.9 months postoperatively. The patients were categorized by smoking history into 2 groups: 39 smokers and 194 nonsmokers. The 2 groups did not differ significantly in age, sex, operative technique, preinjury Tegner score, or mean time until postoperative MRI. The primary outcome was graft rupture rate, with rupture confirmed by either arthroscopic assessment or postoperative MRI diagnosis. The secondary outcome measure was degree of graft ligamentization, evaluated by measuring the signal-to-noise quotient (SNQ) of the graft.

Results

The overall ACL graft rupture rate was 6.0%. The rupture rate was significantly higher in smokers than in nonsmokers (12.8% vs 4.6%, respectively; P = .0498). Smokers also had a significantly higher whole-graft SNQ compared with nonsmokers (4.7 ± 4.4 vs 3.3 ± 3.7, respectively; P = .028), suggesting less satisfactory ligamentization in smokers.

Conclusion

Smoking was associated with a higher risk of graft rupture of ACL reconstruction and a higher SNQ of the intact graft as shown on postoperative MRI.

Personal and narrative review of the current management of the injured anterior cruciate ligament of the knee in the UK with reference to surgical treatment versus rehabilitation

Rupture of the anterior cruciate ligament of the knee is a common injury occurring mostly in young athletic individuals taking part in pivoting, cutting and jumping sports. It is demonstrated by anterolateral rotatory instability on clinical testing. As yet there are no clear guidelines as to whom will benefit from surgical reconstruction as opposed to rehabilitation alone, apart from elite athletes (defined as varsity players or those participating in sport at national or international level). Also, some adolescent knees and those with combined injuries, usually meniscal tears, may benefit from surgery. Even after surgery there is an increased incidence of rerupture and the development of degenerative changes in the operated knee, particularly in the young athlete who has returned to a high level of sporting activity. Early diagnosis is essential to provide a focused care pathway and to avoid the consequences of chronic cruciate insufficiency.

Currently, it seems that too many anterior cruciate ligament reconstructions may be undertaken where rehabilitation alone would have sufficed. Better preoperative clinical testing including improved arthrometric assessment, muscle and neurological testing and imaging including radiology and MRI may help refine the diagnosis, thus enabling a better decision on further management. There is also a requirement for better designed clinical studies reporting on the outcomes of treatment be it either surgical or conservative.