Reproducibility of the native ACL mid-substance cross-sectional area in anatomical single bundle ACL reconstruction

Purpose

The purpose of this study was to evaluate the reproducibility of the native anterior cruciate ligament (ACL) mid-substance cross sectional area in anatomic single-bundle ACL reconstruction.

Methods

Fifty-eight subjects who were performed anatomic single-bundle ACL reconstruction were included. Cross section size of the ACL graft was calculated from the graft diameter during surgery. Computed tomography (CT) of the knee was performed pre-operatively. Following Iriuchishima's report, native ACL size was estimated from the axial CT image of intercondylar notch area of femur at the most distal level of Blumensaat's line (In the report, native ACL size was equal to 14% of the intercondylar notch area of femur). The measured ACL graft cross-sectional size and estimated native ACL size were compared and correlation was evaluated.

Results

Measured ACL graft cross-sectional size was 49 ± 14 mm2. Measured intercondylar notch area of femur at the most distal level of Blumensaat's line was 372 ± 91.6 mm2, and estimated native ACL size was 53 ± 12.5 mm2. Measured ACL graft cross-section and estimated native ACL showed no significant size difference. Measured ACL graft cross-section and estimated native ACL had no significant size correlation.

Conclusion

Native ACL cross-sectional size was reproduced in anatomic single-bundle ACL reconstruction. However, as measured ACL graft and estimated native ACL showed no size correlation, it is possible that size of native ACL might not be reproduced. Such cases would be susceptible to the risk of graft impingement or knee instability.

Use of electromyographic biofeedback in rehabilitation following anterior cruciate ligament reconstruction: a systematic review and meta-analysis

BACKGROUND

Rehabilitation following anterior cruciate ligament (ACL) reconstruction surgery is essential to regain functionality and return to previous activity level. Electromyographic biofeedback may be an effective intervention for rehabilitation of patients following ACL surgery.

OBJECTIVE

To synthesize the available evidence on the effect of electromyographic biofeedback in the treatment of quadriceps strength following ACL surgery.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

PubMed, EMBASE, CENTRAL and Epistemonikos were searched.

ELIGIBILITY CRITERIA

Randomized clinical trials with patients undergoing ACL reconstruction surgery comparing biofeedback with a standard rehabilitation control group.

DATA EXTRACTION AND DATA SYNTHESIS

Two authors selected articles and performed data extraction. The analysed outcomes were strength, function, pain, knee extension and balance. The risk of bias of individual studies was assessed using the Cochrane Risk of Bias Tool. Results were combined through random-effects meta-analysis, reporting mean differences.

RESULTS

Eight articles were included in the qualitative analysis, and four articles were included in the quantitative analysis. The interventions lasted between 4 and 12 weeks. Three studies evaluated the effect of biofeedback on quadriceps strength; of these, two studies showed a significant difference in favour of the biofeedback group. In addition, biofeedback was found to improve knee extension [standardized mean difference - 1.3, 95% confidence interval (CI) - 1.74 to -0.86] and balance (one study). There was no significant difference in Lysholm score (mean difference -6.21, 95% CI -17.51 to 5.08; I2 =59%) or pain between the biofeedback group and the control group.

CONCLUSION

Electromyographic biofeedback in knee rehabilitation could be useful following ACL reconstruction surgery.

KEY MESSAGES

SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO (CRD42020193768).

Femoral interference screw divergence as a result of anteromedial portal insertion and outside-in FlipCutter femoral tunnel drilling: A cadaveric study

Aims and objectives

To investigate whether interference screw fixation through an anteromedial portal into an outside-in drilled femoral tunnel via a flip cutter results in acceptable hardware position.

Materials & methods

10 cadaveric knees underwent ACL-reconstruction with patellar BTB autograft. Femoral tunnel drilling was performed utilizing an outside-in flip cutter drill and interference screws for femoral fixation. Lateral and anterior-posterior (AP) fluoroscopic images were taken to measure screw divergence within the femoral tunnel. The means of AP and lateral divergence angles were compared using two-tailed t-tests.

Results

Using the flip cutter, the AP and lateral divergence angles were 7.3° ± 4.5° and 9.3° ± 9.3°, respectively, while the total divergence angles were 16.6° ± 11.8°. Divergence angles using a cannulated reamer were found to be 14.4° ± 2.5° and 6.8° ± 2.8° for AP and lateral, respectively and 21.1° ± 5.2° for the total divergence. The AP divergence angles using the flip cutter were significantly less than those reported using a cannulated reamer (p = 0.001).

Conclusions

The flip cutter method resulted in significantly reduced divergence angle between the screw and graft when compared to previous cadaveric studies in the coronal plane. There was no significant difference in divergence angle in the sagittal plane. Both methods appear to result in divergence angles below the threshold which would be considered to significantly decrease pull-out strength. Large standard deviations also reflect limited sample size but may also suggest more variability in divergence when compared to historical control set. This study clearly establishes the outside-in technique using a retrograde reamer as a viable independent femoral drilling solution for ACL reconstruction when using a BTB autograft with a femoral interference screw.

Intra- and interobserver reliability of two classification systems for posterolateral tibial plateau fractures in the setting of an ACL rupture

Background

Posterolateral tibial plateau impaction fractures occur frequently associated with anterior cruciate ligament (ACL) tears. Some authors advocate operative treatment of high-grade impaction fractures, which has led to the development of classification systems. Our study aims (1) to describe and compare the intra- and interobserver reliability of the two most used classifications and (2) to assess correlations between the grade of bony posterolateral tibial injury, patient characteristics and short-to mid-term revision rate after ACL reconstruction.

Materials and methods

In a retrospective series of 163 patients who underwent ACL reconstruction, two reviewers independently evaluated the preoperative MRI scans. Conform the Menzdorf and Bernholt classification the presence and grade of an associated posterolateral impaction fracture were assessed. Statistical analyses were performed to test for both study hypotheses.

Results

171 primary ACL cases were evaluated. Mean follow-up time was 41 months (range 12-154, SD = 17.1). Mean age was 32 years (range 13-59, SD = 12). Posterolateral impaction fractures were present in 111 (64.9 %) and 120 (70.0 %) cases, according to the Menzdorf and Bernholt classification. A Segond fracture was present in 19 (11.1 %) cases. Kappa value was 0.47 for intra- and 0.52 for the interobserver reliability for the Menzdorf classification (moderate reliability). For the Bernholt classification kappa values were 0.66 and 0.61, respectively (good reliability). A Segond fracture correlated significantly with the presence of a posterolateral impaction fracture (p < 0.05). A significant association was present between patients necessitating ACL revision surgery and patients for whom operative intervention for the posterolateral impression was advised following the Menzdorf classification (p < 0.001).

Conclusion

Inter- and intraobserver reliability testing for classifying posterolateral tibial fractures resulted in moderate to good reliability. High-grade posterolateral tibial fractures should be identified, selective treatment should be considered as they are associated with higher revision rates after ACL reconstruction if left untreated.

Brain functional connectivity alterations in patients with anterior cruciate ligament injury

Recent advancements in neuroimaging have illustrated that anterior cruciate ligament (ACL) injuries could impact the central nervous system (CNS), causing neuroplastic changes in the brain beyond the traditionally understood biomechanical consequences. While most of previous functional magnetic resonance imaging (fMRI) studies have focused on localized cortical activity changes post-injury, emerging research has suggested disruptions in functional connectivity across the brain. However, these prior investigations, albeit pioneering, have been constrained by two limitations: a reliance on small-sample participant cohorts, often limited to two to three patients, potentially limiting the generalizability of findings, and an adherence to region of interest based analysis, which may overlook broader network interactions. To address these limitations, our study employed resting-state fMRI to assess whole-brain functional connectivity in 15 ACL-injured patients, comparing them to matched controls using two distinct network analysis methods. Using Network-Based Statistics, we identified widespread reductions in connectivity that spanned across multiple brain regions. Further modular connectivity analysis showed significant decreases in inter-modular connectivity between the sensorimotor and cerebellar modules, and intra-modular connectivity within the default-mode network in ACL-injured patients. Our results thus highlight a shift from localized disruptions to network-wide dysfunctions, suggesting that ACL injuries induce widespread CNS changes. This enhanced understanding has the potential to stimulate the development of strategies aiming to restore functional connectivity and improve recovery outcomes.

Management of Anterior Cruciate Ligament Tears in Skeletally Immature Patients

PURPOSE OF REVIEW

Anterior cruciate ligament (ALC) tears are increasingly common in skeletally immature patients, as more children and adolescents participate in intensive sports training and specialization at increasingly younger ages. These injuries were historically treated nonoperatively, given concerns for physeal damage and subsequent growth disturbances after traditional ACL reconstruction techniques. However, there is now sufficient data to suggest superior outcomes with operative treatment, specifically with physeal-sparing and physeal-respecting techniques. This article reviews considerations of skeletal maturity in patients with ACL tears, then discusses surgical techniques, with a focus on their unique indications and outcomes. Additional surgical adjuncts and components of postoperative rehabilitation, which may reduce retear rates, are also considered.

RECENT FINDINGS

Current research shows favorable patient-reported outcomes and high return-to-sport rates after ACL reconstruction in skeletally immature patients. Graft rupture (ACL retear) rates are low, but notably higher than in most adult populations. Historically, there has been insufficient research to comprehensively compare reconstruction techniques used in this patient population. However, thoughtful systematic reviews and multicenter prospective studies are emerging to address this deficit. Also, more recent data suggests the addition of lateral extra-articular procedures and stringent return-to-sports testing may lower retear rates. Physeal-sparing and physeal-respecting ACL reconstructions result in stabilization of the knee, while respecting the growth remaining in children or skeletally immature adolescents. Future research will be essential to compare these techniques, given that more than one may be appropriate for patients of a specific age and skeletal maturity.

[Research progress of femoral bone tunnel positioning in anterior cruciate ligament reconstruction]

Objective

To review the concept and methods of femoral bone tunnel positioning in anterior cruciate ligament (ACL) reconstruction, in order to provide a reference for clinical treatment.

Methods

The relevant literature on the concept and methods of femoral bone tunnel positioning in ACL reconstruction in domestic and international research was extensively reviewed.

Results

The position of the femoral bone tunnel is a key factor in determining the prognosis of ACL reconstruction. The concept of femoral bone tunnel positioning in ACL reconstruction has experienced isometric reconstruction, anatomical reconstruction, Ribbon-like theory, I.D.E.A.L. theory, and nearly isometric reconstruction theory. The femoral bone tunnel positioning technique is also changing with the in-depth study of the anatomy and biomechanics of the ACL, and each bone tunnel positioning technique has its own advantages and disadvantages. Over-The-Top technique is now mainly used for ACL revision; the clock-face positioning method is basically no longer applicable due to the large error, poor stability, and low retrievability; the bone landmarks positioning method (the lateral condyle of the femur's Resident's ridge and bifurcation ridge, and the the apex of the deep cartilage), which is now mostly used clinically due to the more constant anatomical landmarks. The quadrant method under X-ray fluoroscopy is more cumbersome to implement intraoperatively, so it is mainly used for academic research; computer navigation-assisted positioning has gradually become popular in recent years, which is highly accurate, avoids the influence of human factors on the positioning of the bone tunnel, and has a very good prospect of application; three-dimensional printing-assisted positioning technology, which is accurate in positioning, with a high degree of reproducibility and a short learning curve.

Conclusion

The concept of femoral bone tunnel positioning for ACL reconstruction has undergone several evolutions, reflecting the deepening of the understanding of ACL and the improvement of the clinical results of reconstruction. The precision, personalization, and intelligence of positioning techniques are the focus of current and future development.

Italian research on anterior cruciate ligament: a bibliometric analysis

INTRODUCTION

This study analysed the trend of publications on anterior cruciate ligament (ACL) in Italy. It was hypothesised that publications on this topic have quickly increased in recent years due to increased knowledge of both clinical and radiological pathology.

METHODS

PubMed and Scopus were accessed on 29/11/2023. This retrieved 838 articles from PubMed and 1050 from Scopus. We analysed the top 10 authors, and journals in publication numbers, citation numbers, and citations per year. We have also looked at the top 10 institutions publishing on anterior cruciate ligament from Scopus as PubMed does not give this information in the output. Data mining was performed using the Orange software, Mac version 3.32.0 ( https://orangedatamining.com/ ) from the titles of all articles. A word cloud analysis of titles, authors, journals and universities was performed.

RESULTS

The peak of citations was in 2017 with 1529, whilst the peak of publications was in 2019 with 59 articles published. Analysing the number of publications and citations for the journal, the most impacted journal is Knee Surgery, Sports Traumatology, Arthroscopy with 5472 citations and 183 articles, followed by The American Journal of Sports Medicine, with 2722 citations and 56 articles and Arthroscopy with 1990 citations and 62 articles. Considering also international collaborations, the most cited author is Della Villa F. in 2020 with 43.67 citations per year. The Italian author with the major number of publications is Zaffagnini S. with 39 articles, whilst the author with the higher number of citations is Aglietti P. with 1612 citations.

CONCLUSIONS

ACL reconstruction has gained growing interest amongst the scientific community. Publications and citations presented a rising trend, the majority of the highly cited papers were contributed by few centres, and clinical trials were the most cited study designs. The long-term outcomes of ACL lesions have attracted interest. The authors hypothesised that shortly there will be an increase in articles analysing the results of ACL revisions, the use of lateral extra-articular tenodesis, and meniscus transplants.

LEVEL OF EVIDENCE IV

Cross-Sectional Study.

Recruitment and baseline characteristics of young adults at risk of early-onset knee osteoarthritis after ACL reconstruction in the SUPER-Knee trial

Objectives

The study aims to (1) report the process of recruiting young adults into a secondary knee osteoarthritis prevention randomised controlled trial (RCT) after anterior cruciate ligament reconstruction (ACLR); (2) determine the number of individuals needed to be screened to include one participant (NNS) and (3) report baseline characteristics of randomised participants.

Methods

The SUpervised exercise-therapy and Patient Education Rehabilitation (SUPER)-Knee RCT compares SUPER and minimal intervention for young adults (aged 18-40 years) with ongoing symptoms (ie, mean score of <80/100 from four Knee injury and Osteoarthritis Outcome Score subscales (KOOS4)) 9-36 months post-ACLR. The NNS was calculated as the number of prospective participants screened to enrol one person. At baseline, participants provided medical history, completed questionnaires (demographic, injury/surgery, rehabilitation characteristics) and underwent physical examination.

Results

1044 individuals were screened to identify 567 eligible people, from which 184 participants (63% male) enrolled. The sample of enrolled participants was multicultural (29% born outside Australia; 2% Indigenous Australians). The NNS was 5.7. For randomised participants, mean±SD age was 30±6 years. The mean body mass index was 27.3±5.2 kg/m2, with overweight (43%) and obesity (21%) common. Participants were, on average, 2.3 years post-ACLR. Over half completed <8 months of postoperative rehabilitation, with 56% having concurrent injury/surgery to meniscus and/or cartilage. The most affected KOOS (0=worst, 100=best) subscale was quality of life (mean 43.7±19.1).

Conclusion

Young adults post-ACLR were willing to participate in a secondary osteoarthritis prevention trial. Sample size calculations should be multiplied by at least 5.7 to provide an estimate of the NNS. The SUPER-Knee cohort is ideally positioned to monitor and intervene in the early development and trajectory of osteoarthritis.

Trial registration number

ACTRN12620001164987.

[Subtuberosity anterior closing wedge osteotomy to correct the increased posterior slope of the tibial plateau]

OBJECTIVE

Reduction of increased reclination of the tibial plateau (posterior slope) to improve the anterior stability of the knee joint.

INDICATIONS

Increased posterior reclination of the tibial plateau greater than 12° in combination with recurrent instability after anterior cruciate ligament (ACL) reconstruction.

CONTRAINDICATIONS

Hyperextension of more than 15° (relative).

SURGICAL TECHNIQUE

Anterior skin incision approximately 8-10 cm above the tibial tuberosity. Insertion of two converging guidewires directly below the patellar tendon ending obliquely in the area of the posterior cruciate ligament (PCL) insertion. Control of the wire position with the image intensifier core. Oscillating saw osteotomy. Removal of the wedge and closure of the osteotomy. Osteosynthesis with interfragmentary screw and medial angle-stable plate.

POSTOPERATIVE MANAGEMENT

Partial load with 10-20 kg for 2 weeks, then step by step increase in load. Mobility: free.

RESULTS

To date we have operated on 36 patients with recurrent instability after ACL reconstruction (20 men, 16 women, average age 34.4 years) in the manner described in this article. In 25 cases, enlarged bone tunnels were filled with allogeneic bone at the same time. The posterior slope of the tibial plateau could be reduced from an average of 14.5° to 8.8°. In 28 cases another ACL reconstruction was performed after an interval of 4-12 months. The Lysholm score significantly increased from 76.3 points to 89.2 points.

Arthroscopic Anterior Cruciate Ligament Reconstruction Learning Curve: Analysis of Operating Time and Clinical Outcomes

Background

Technical proficiency for arthroscopic anterior cruciate ligament reconstruction (ACLR) is complex and requires learning and practice. Achieving an appropriate level of competency with this surgery is important for patient safety and satisfactory surgical outcomes. There is limited literature about the learning curve in ACLR in Africa.

Objectives

This study aimed to demonstrate the learning curve associated with ACLR.

Materials and Methods

This retrospective study on arthroscopic ACLR was conducted between January 2020 and June 2023 with a minimum of 12 months follow-up. The primary outcome measure was operation time, whereas the secondary outcome measures were functional outcome and postoperative complications.

Results

One hundred fifty-nine ACLR met the inclusion criteria and were analysed. The mean age of the patients was 31.47 ± 9.50 years. There were 148 (93.1%) males and 11 (6.9%) females. The median operation time was 50 min (45-190 min). There was progressively decreasing operation time with increasing number of cases done until after the first 19 cases. The mean operating time for the first 19 cases was 143.89 ± 32.84 min, whereas the mean operating time for the later 140 cases was 53.81 ± 9.72 min (P = 0.000).

Conclusions

The operation time for arthroscopic ACLR progressively decreased until after the first 19 cases. There was, however, no significant difference in the clinical outcome between the cases done during the learning curve and those done at proficiency.

A study regarding the anterior cruciate ligament remnant: Differences in balance and postural control between remnant-preserving and remnant-non-preserving patients

INTRODUCTION

The anterior cruciate ligament (ACL) is the most frequently injured ligament of the knee. However, quantitative studies on evaluate the postural control influence resulted from the ACL remnant preservation or not are scarce. The aim of this study is to evaluate the postural control of patients submitted to ACL reconstruction with and without preservation of the injured remnant in pre and postoperative periods.

METHODS

Eighteen patients underwent ACL reconstruction and separated into 2 groups according to the preservation or not of the remnant: (I) submitted to ACL reconstruction with preservation of the remnant (10 patients); (II) submitted to ACL reconstruction without preservation of the remnant (8 patients). They were assessed using the Lysholm score and force plate, which evaluated the patient's postural stability for remnant and non-remnant preservation in ACL reconstruction surgery.

RESULTS

Group I showed statistically significant subjective and objective improvements, both at 3 and 6 months. Additionally, improvement of the Lysholm test at 6 months in Group II was also statistically significant. Furthermore, the results of the Friedman test for the VCOP and VY variables of Group I, with support of the injured side in the force plate, showed a statistically significant difference both for pre and postoperative period at 3 months, compared to the 6-month postoperative period. The variables EAC and VX were statistically different for Group II, considering the preoperative period, 3 and 6 months postoperatively.

CONCLUSION

Preserving the ACL remnant in patients with ACL injuries has a positive impact on postural stability during recovery.

What exercise programme is the most appropriate to mitigate anterior cruciate ligament injury risk in football (soccer) players? A systematic review and network meta-analysis

OBJECTIVES

To examine the effectiveness of different exercise-based interventions to mitigate the risk of anterior cruciate ligament injury in football players, and to determine which is the most appropriate for them, specifically for female football players.

DESIGN

Four databases were accessed in July 2023 using the keywords football, soccer, athletic injuries, anterior cruciate ligament, knee injuries, injury prevention, exercise-based programme, and risk factor.

METHODS

Randomised controlled trials that evaluated any exercise-based injury prevention intervention compared with a control group on the prevention of anterior cruciate ligament injury in football players were included.

RESULTS

Eleven studies were included. Data were presented as logarithm hazard ratio, credible intervals and standard deviation. FIFA 11+ was the most effective in reducing anterior cruciate ligament injury risk in football players (logarithm hazard ratio = -1.23 [95% credible intervals: -2.20, -0.35]; SD = 0.47), followed by the Knäkontroll programme (logarithm hazard ratio = -0.76 [95% credible intervals: -1.60, -0.03]; standard deviation = 0.42). For females, only Knäkontroll had a significant impact on reducing the risk of anterior cruciate ligament injury (logarithm hazard ratio = -0.62 [95% credible intervals: -1.71, 0.62]; standard deviation = 0.58).

CONCLUSIONS

Our results support the use of FIFA 11+ and Knäkontroll to mitigate injury incidence at overall level. However, the effectiveness of these interventions changed when adjusting for females. Knäkontroll is postulated as the programme with the greatest preventive nature, although these results should be interpreted with caution due to the lack of the sample.

Factors affecting the post-operative over-constraint after anatomic double-bundle anterior cruciate ligament reconstruction

Objective

Initial tension at graft fixation is one of key factors for good outcomes in anterior cruciate ligament (ACL) reconstruction. Identifying the pre-operative factors that influence postoperative knee laxity under the anterior tibial load is useful in determining the initial tension at graft fixation. Thus, the purpose of this study was to clarify the pre-operative factors affecting the side-to-side difference in anterior laxity immediately after the anatomic double-bundle ACL reconstruction with a constant initial tension.

Methods

Fifty-five patients underwent the anatomic double-bundle ACL reconstruction with hamstring tendon grafts. Anterior tibial displacement (ATD) was measured on both knees using KT-2000 Knee Arthrometer under anterior drawer load of 67 N, 89 N, 134 N and manual maximum load at 30° of flexion before ACL reconstruction under anesthesia, and was also measured on the operated knees under 89 N immediately after ACL reconstruction under anesthesia. Then, side-to-side difference (SSD) before and immediately after ACL reconstruction was calculated. Correlative relation between the SSD immediately after ACL reconstruction and the ATD/the SSD in each condition was analyzed.

Results

The side-to-side difference of ATD immediately after surgery was -3.8 ± 1.7 mm (0 to -8mm) in response of 89 N of anterior load. There was correlation between the SSD immediately after ACL reconstruction and all ATD on both knees except for the ATD under manual maximum load on the injured knee, while little correlation between the SSD immediately after ACL reconstruction and that before ACL reconstruction was found. Especially, ATD under 89 N on the opposite knees and ATD under 134 N on the injured knees showed selective correlation with the SSD immediately after surgery in the step-wise multiple regression analysis.

Conclusion

As the anterior tibial displacements under 89 N on the contra-lateral knee and under 134 N on the injured knee had a significant correlation with the SSD immediately after ACL reconstruction, those values may be helpful in determining the increase or decrease in initial tension at graft fixation.

Instrument-based anterolateral rotatory laxity assessment of the knee has a high intra-observer and inter-observer reliability: a systematic review

IMPORTANCE

A reliable evaluation of anterolateral rotatory instability in the anterior cruciate ligament (ACL) deficient knee is important to help surgeons determine which patients might need concurrent anterolateral augmentation procedures.

OBJECTIVE

The purpose of this study was to systematically review studies that assess the intra-observer and inter-observer reliability of instruments used to measure anterolateral rotatory laxity of the knee.

EVIDENCE REVIEW

A comprehensive literature review was conducted according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, using PubMed, Embase, Scopus, and Google Scholar databases for original, English-language studies evaluating the reliability of objective or instrument-based anterolateral rotatory laxity of the knee until October 31, 2022. Reliability data were extracted from text, tables, and figures.

FINDINGS

Twelve studies, with patients between the ages of 14-63 years, were included. The instruments used to measure anterolateral rotatory knee laxity included inertial sensors (n ​= ​9), magnetic resonance imaging (n ​= ​1), and navigation systems (n ​= ​2). The global intra-observer intraclass correlation coefficient for these devices was between 0.63 and 0.97, and the global inter-observer reliability was between 0.63 and 0.99.

CONCLUSION AND RELEVANCE

Instrument-based anterolateral rotatory knee laxity assessment has moderate to good intra- and inter-observer reliability. Evaluating anterolateral instability in ACL-deficient knees with these devices could help in decision-making when considering anterolateral augmentation.

LEVEL OF EVIDENCE

IV.

[Evolving indications for partial knee replacement : New aspects]

BACKGROUND

Partial knee replacement has proven to be an effective therapy for advanced unicompartmental arthrosis of the knee. Despite continuous advancements in implants and surgical techniques over the past decades, the global preference for total knee arthroplasty still persists for historical reasons.

OBJECTIVES

This report aims to illuminate advantages and disadvantages of partial knee replacement considering long-term results, the evolution of indication criteria over recent decades and new aspects in patient selection with potential improvements through emerging technologies.

MATERIAL AND METHODS

The analysis involves the examination of long-term results from clinical studies and registry data, highlighting the risk factors for potential failures and their influence on the development of indication criteria.

RESULTS

Present-day long-term results demonstrate excellent prosthetic survival, aligning with outcomes from total knee arthroplasty. New perspectives for expanding indication criteria are discussed, including the possible application of partial knee replacement in cases of severe varus deformity > 15°, anterior cruciate ligament insufficiency, young active patients, anterior knee pain, and/or patellofemoral arthritis, as well as mild radiographic arthritis with degenerative medial meniscus root tear and meniscal extrusion.

DISCUSSION

Indication criteria have consistently expanded in recent years, taking into account modern insights, and the application of advanced technologies can enhance precision and minimize surgical errors. Furthermore, this report emphasizes that revision rates are not the sole criterion for success and underscores the necessity for a comprehensive examination of clinical results.

Injuries to both anterolateral ligament and Kaplan fiber of the iliotibial band do not increase preoperative pivot-shift phenomenon in ACL injury

Background

To assess the incidence of anterolateral ligament (ALL) and Kaplan fiber of the iliotibial band (KF) injuries in patients with acute anterior cruciate ligament (ACL) injury on magnetic resonance imaging (MRI), and to investigate the association between these injuries and the magnitude of preoperative pivot-shift test.

Method

One-hundred and five patients with primary ACL injury were retrospectively reviewed. ALL injury and KF injury were assessed by preoperative MRI, and subjects were allocated into four groups: Group A, neither injury; Group B, only ALL injury; Group C, only KF injury; Group D, simultaneous ALL and KF injuries. Before ACL reconstruction, tibial acceleration during the pivot-shift test was measured by an electromagnetic measurement system, and manual grading was recorded according to the International Knee Documentation Committee (IKDC) guideline.

Results

In MRI, the ALL was identified in 104 patients (99.1%) and KF in 99 patients (94.3%). ALL and KF injuries were observed in 43 patients (43.9%) and 23 patients (23.5%), respectively. Patient distribution to each group was as follows; Group A: 43 patients (43.9%), Group B: 32 patients (32.7%), Group C: 12 patients (12.2%), Group D: 11 patients (11.2%). No significant differences were observed in tibial acceleration, and manual grading among the four groups.

Conclusion

Simultaneous injury to both ALL and KF was uncommon, and preoperative pivot-shift phenomenon did not increase even in those patients. The finding suggests that the role of ALL and KF in controlling anterolateral rotatory knee laxity may be less evident in the clinical setting compared to a biomechanical test setting.

High prevalence of associated injuries in anterior cruciate ligament tears: A detailed magnetic resonance imaging analysis of 254 patients

OBJECTIVES

To evaluate the type and prevalence of associated injuries by using magnetic resonance imaging (MRI) in patients with anterior cruciate ligament (ACL) tears.

METHODS

Data from the Natural Corollaries and Recovery after ACL injury multicenter longitudinal cohort study were analyzed. Between May 2016 and October 2018, patients aged between 15 and 40 years, who had experienced an ACL tear within the last 6 weeks and sought medical attention at one of seven healthcare clinics in Sweden, were invited to participate. The mean time from injury to MRI was 19.6 ± 15.2 days. An orthopedic knee surgeon and a musculoskeletal radiologist reviewed all the MRI scans. The following structures were assessed: posterior cruciate ligament (PCL), medial collateral ligament (MCL) complex, lateral collateral ligament (LCL), popliteus tendon, medial meniscus (MM), lateral meniscus (LM), and cartilage. In addition, the presence of bone bruising, impaction fractures in the lateral femoral condyle (LFC) or posterolateral tibia (PLT), and Segond fractures were also assessed.  RESULTS: A total of 254 patients (48.4% males) with a mean age of 25.4 ± 7.1 years were included. The prevalence of associated injuries was as follows: PCL (0.4%), MCL {41.3% [superficial MCL and deep MCL (dMCL) 16.5%; isolated dMCL 24.8%]}, LCL (2.4%), MM (57.4%), LM (25.2%), cartilage (15.0%), bone bruising (92.9%), impaction fracture in the LFC (45.7%) and PLT (4.7%), and Segond fracture (7.5%).

CONCLUSIONS

The prevalence of associated injuries in patients with ACL tears was high. The findings reported in this study may serve as a reference tool for orthopedic surgeons and radiologists in the diagnosis of associated injuries using MRI in patients with ACL tears.

Cyclops syndrome following anterior cruciate ligament reconstruction: Can relapse occur after surgery?

Symptomatic cyclops lesions are complications that can be seen at rates of up to approximately 10% after anterior cruciate ligament reconstruction. However, recurrent cyclops lesions have rarely been documented. There are case rare series in the literature regarding the treatment of recurrent cyclops lesion. Future large studies are needed to investigate factors contributing to the development of cyclops lesions and syndrome and treatment options.

The "Golden Age" of quadriceps tendon grafts for the anterior cruciate ligament: a bibliometric analysis

IMPORTANCE

Bibliometric research is a statistical analysis of publications to measure the scientific output in a specific field in order to highlight medical developments or knowledge gaps and to direct future scientific research. The quantity of orthopedic papers on the internet is astounding and is steadily growing as a result of recent advancements in technology and medicine. This is why choosing the right information is essential.

AIM

The purpose of this study was to analyze the current literature for trends in publications regarding quadriceps tendon (QT) grafting of the anterior cruciate ligament (ACL).

EVIDENCE REVIEW

PubMed was searched on August 28, 2023. References were collected from PubMed, and trends were analyzed using this information. This search retrieved 405 articles regarding human and animal studies. We analyzed the top 10 authors and journals in terms of publication numbers, citation numbers, and citations per year. The PubMed-by-year feature was used to compare the number of publications regarding ACL reconstruction by quadriceps grafting with all publications in PubMed.

FINDINGS

The number of yearly publications averaged 10 or less up to 2018, starting from 1982 when the first paper on the QT was published. However, the number of publications increased from 2018. While the total number of publications on this topic was 405, 260 were published from 2018 alone. The number of citations was 8262 in total overall years. It is expected that the last five years' publications, especially those for the last year, will be low in number, as it takes time for citations to accrue. The journal Arthroscopy published the most articles on this topic, with 57 papers and 1884 citations, followed by the American Journal of Sports Medicine, with 39 articles and 1576 citations. The top three journals on this topic were Arthroscopy, AmericanJournalofSportsMedicine, and KneeSurgery, SportsTraumatology, Arthroscopy. The most published author was Musahl V (with 24 articles), and the most cited author was Xerogeanes JW (with 570 citations).

CONCLUSIONS AND RELEVANCE

Global trend analysis suggests that research on anterior cruciate ligament reconstruction with the quadriceps has significantly increased in the last 5 years and that the number of papers on this topic is increasing steadily. We found that the publications and citations are exhibiting a rising trend, Arthroscopy is the most impactful journal, and Musahl V is the most impactful author on the topic. Xerogeanes JW is the author with the most citations on the topic. The promising clinical results of anterior cruciate ligament reconstruction with the QT have attracted the most research interest.

LEVEL OF EVIDENCE

Level IV.

Not all patient-reported outcome measures are equivalent at two years compared to one year after anterior cruciate ligament reconstruction based on a retrospective analysis

OBJECTIVE

This article aims to assess for clinically important differences in patient-reported outcome measures (PROMs) at one and two years post anterior cruciate ligament reconstruction (ACLR).

METHODS

A retrospective comparison of prospectively collected PROMs for a single cohort who underwent a primary ACLR with or without associated meniscal surgery from 2016 to 2020 was assessed. Six externally validated PROMs were collected preoperatively and at standardized times postoperatively. Descriptive statistics and paired equivalence testing of PROMs at one and two years after surgery was completed using previously published or calculated minimal clinically important differences as upper and lower equivalence limits. A repeated measures analysis of PROMs that were not clinically equivalent at one and two years after surgery was completed to assess for a clinically significant difference. Subgroup analyses based on sex, age and associated meniscal injury were completed.

RESULTS

One-hundred and forty-five participants with a mean age of 28.7 years (standard deviation: 9.9 years) were included in the final analysis. All PROMs were clinically equivalent at two years compared to one year after ACLR except the quality of life and sport and recreation domains of the Knee Injury and Osteoarthritis Outcome Score (KOOS). The quality of life (mean difference (MD):12.3, P ​< ​0.01, effect size (η2): 0.65) and sport and recreation (MD: 8.78, P ​< ​0.01, η2: 0.50) domains of the KOOS were clinically different at two years compared to one year postoperatively. No major differences were found in the subgroup analyses compared to the entire included sample.

CONCLUSION

While most PROMs were equivalent at two years compared to one year after ACLR, the quality of life and sport and recreation domains of the KOOS, which reflect knee performance during higher demand activities, exhibited a clinically significant difference.

LEVEL OF EVIDENCE

IV.

The NordBord test reveals persistent knee flexor strength asymmetry when assessed two and five years after ACL reconstruction with hamstring tendon autograft

OBJECTIVE

Comparison of knee flexor strength limb symmetry index (LSI) between the NordBord-test and the Biodex-test, and to determine the relationship between knee flexor strength and function in patients 2 and 5 years after anterior cruciate ligament reconstruction (ACL-R) with hamstring tendon (HT) autografts.

DESIGN

Observational registry study.

SETTING

Primary care.

PATIENTS

Cross-sectional data from 96 patients (55% women) participating in a rehabilitation-registry after ACL-R with HT autografts.

MAIN OUTCOME MEASURES

Comparison of knee flexor strength symmetry between the Biodex-test and the NordBord-test. Secondly, the relationship between knee flexor strength test and perceived knee function, activity level, and hop performance.

RESULTS

The NordBord-test demonstrated greater strength deficits compared to the Biodex-test with a mean difference of 12.5% ± 15.1% 95 % CI [8.1; 16.9%] at 2 years, and 11.1% ± 11.9% 95 % CI [7.7; 14.6 %] at 5 years after ACL-R. Relative concentric knee flexor strength (Nm/kg) in the Biodex demonstrated significant weak-to-moderate correlations with activity level and hop performance (r = 0.33-0.67) at 2 and 5 years.

CONCLUSION

The NordBord-test identified deficits in knee flexor strength LSI not seen with the Biodex-test at 2 and 5 years after ACL-R. No significant correlations were found between the persistent knee flexor strength asymmetry and perceived function, activity level or hop performance.

Are inter-limb differences in change of direction velocity and angle associated with inter-limb differences in kinematics and kinetics following anterior cruciate ligament reconstruction?

BACKGROUND

Quantifying inter-limb differences in kinematics and kinetics during change of direction is proposed as a means of monitoring rehabilitation following anterior cruciate ligament reconstruction (ACLR). Velocity and centre of mass (CoM) deflection angle are fundamental task descriptors that influence kinematics and kinetics during change of direction. Inter-limb differences in approach velocity and CoM deflection angle have been identified following ACLR and may contribute to the presence of inter-limb differences in kinematics and kinetics during change of direction.

RESEARCH QUESTION

The aim of this study was to quantify the proportion of variance in kinematic and kinetic inter-limb differences attributable to inter-limb differences in approach velocity and centre of mass deflection angle during a change of direction task.

METHODS

A cohort of 192 patients (male, 23.8 ± 3.6 years, 6.3 ± 0.4 months post primary ACLR) completed a pre-planned 90° change of direction task on both their operated and non-operated limb. Inter-limb differences in approach velocity and CoM deflection angle were calculated alongside lower-extremity kinematic and kinetic variables. The relationship between inter-limb differences in task-level variables and inter-limb differences in kinematic and kinetic variables was examined using linear regression models. Kinematic and kinetic inter-limb differences were adjusted for inter-limb differences in approach velocity and CoM deflection angle. Adjusted and unadjusted inter-limb differences were submitted to one sample t-tests.

RESULTS

Inter-limb differences in approach velocity and centre of mass deflection angle explained 3 - 60% of the variance in kinematic and kinetic inter-limb differences. Statistical inferences remained consistent between adjusted and unadjusted conditions with the exception of hip flexion angle.

SIGNIFICANCE

Inter-limb differences in task-level features explain a large proportion of the variance in inter-limb differences in several kinematic and kinetic variables. Accounting for this variation reduced the magnitude of kinematic and kinetic inter-limb differences comparable to those previously observed in normative cohorts.

Engineering a functional ACL reconstruction graft containing a triphasic enthesis-like structure in bone tunnel for the enhancement of graft-to-bone integration

Background

Anterior cruciate ligament (ACL) rupture is a common sports injury, which causes knee instability and abnormal joint kinematics. The current ACL graft was single-phasic, and not convenient for the formation of enthesis-like tissue in the bone tunnel, resulting in poor integration of graft-to-bone.

Methods

A band-shaped acellular tendon (BAT) was prepared as the core component of the ACL reconstruction graft at first, while sleeve-shaped acellular cartilage (SAC) or sleeve-shaped acellular bone (SAB) was fabricated using a vacuum aspiration system (VAS)-based decellularization protocol. The biocompatibility of the three acellular matrixes was evaluated. Furthermore, a collagen-binding peptide (CBP) derived from the A3 domain of von Willebrand factor was respectively fused into the N-terminal of GDF7, TGFβ3, or BMP2 to synthesize three recombinant growth factors capable of binding collagen (named C-GDF7, C-TGFβ3, or C-BMP2), which were respectively tethered to the BAT, SAC or SAB for improving their inducibilities in stem cell differentiation. An in-vitro experiment was performed to evaluate theirs osteogenic, chondrogenic, and tenogenic inducibilities. Then, C-TGFβ3-tethering SAC (C-TGFβ3@SAC) and C-BMP2-tethering SAB (C-BMP2@SAB) were sequentially surrounded at the bone tunnel part of C-GDF7-tethering BAT (C-GDF7@BAT), thus a sleeve-shaped acellular graft with a triphasic enthesis-like structure in bone tunnel part (named tissue-engineered graft, TE graft) was engineered. Lastly, a canine ACL reconstruction model was used to evaluate the in-vivo performance of this TE graft in enhancing graft-to-bone integration.

Results

The BAT, SAC, and SAB well preserved the structure and components of native tendon, cartilage, and bone, showing good biocompatibility. C-GDF7, C-TGFβ3, or C-BMP2 showed a stronger binding ability to BAT, SAC, and SAB. The C-GDF7@BAT, C-TGFβ3@SAC, or C-BMP2@SAB was a controlled delivery system for the scaffold-specific release of GDF7, TGFβ3, and BMP2, thus showing superior tenogenic, chondrogenic, or osteogenic inducibility, respectively. Using a canine ACL reconstruction model, abundant newly-formed bone and connective collagen fibers could be observed at the integration site between TE graft and bone tunnel at postoperative 16 weeks. Meanwhile, the failure load of the reconstructed ACL by TE graft was significantly higher than that of the autograft.

Conclusion

The TE graft could be used to reconstruct ruptured ACL and augment graft-to-bone integration, thus demonstrating high potential for clinical translation in ACL reconstruction.

Translational potential of this article

The findings of the study indicated that the TE graft could be a novel graft for ACL reconstruction with the ability to augment graft-to-bone integration, which may provide a foundation for future clinical application.

Lever sign test for anterior cruciate ligament injuries: a diagnostic meta-analysis

BACKGROUND

Sports-related ACL (anterior cruciate ligament) injuries are frequent. Successful management requires early diagnosis and treatment. One of the clinical tests used to identify ACL damage is the lever sign test. This meta-analysis aimed to assess the lever sign test's diagnostic efficacy for ACL injuries.

METHODS

An extensive investigation of the Cochrane Library, Embase, and PubMed databases was conducted until April 2023. Studies assessing the lever sign test's diagnostic efficacy for ACL injuries were also included. A bivariate random-effects model was employed to acquire the pooled estimates of diagnostic odds ratios, specificity, positive and negative likelihood ratios, sensitivity, and curves of the summary receiver operating characteristic (SROC).

RESULTS

The meta-analysis comprised twelve investigations with a total of 1365 individuals. The lever sign test's combined sensitivity and specificity for the purpose of diagnosing injuries to the ACL were 0.810 (95% confidence interval [CI] 0.686-0.893) and 0.784 (95% CI 0.583-0.904), respectively. The positive and negative likelihood ratios were 3.148 (95% CI 1.784-5.553) and 0.210 (95% CI 0.084-0.528), respectively. The study revealed a diagnostic odds ratio of 17.656, with a 95% CI ranging from 4.800 to 64.951. The SROC curve's area was determined to be 0.912 (95% CI 0.857-0.967).

CONCLUSION

With high specificity and sensitivity, the lever sign test is a reliable diagnostic modality for ACL injuries. However, the test should be used in combination with other diagnostic tests to increase the accuracy of the diagnosis. Further investigations are warranted to assess the clinical practicability of the lever sign test in various populations and settings.

Is it time to develop specific return to running criteria for ACL rehabilitation? An international survey of physiotherapists criteria for return to running following ACL injury

OBJECTIVE

To determine return to running criteria currently used by physiotherapists following anterior cruciate ligament (ACL) injury.

DESIGN

Self-reported online international survey.

METHODS

An online survey of physiotherapists across Australia, the Netherlands and France.

RESULTS

A total of 476 respondants participated in the survey across Australia (n = 153), the Netherlands (n = 162), and France (n = 161). For return to running criteria following a non-operative approach, the majority of respondents chose swelling (40.55%, n = 193/476), pain (38.24%, n = 182/476), knee extensor strength (34.34%, n = 163/476), single leg squat (31.93%, n = 152/476) and knee flexor strength (29.83%, n = 142/476). After ACL reconstruction, the highest responses were also swelling (41.18%, n = 196/476), pain (37.18%, n = 177/476), knee extensor strength (37.18%, n = 177/476) and single leg squat (33.19%, n = 158/476). From the identified themes the most common cutoff variables were pain between 0 and 3/10, swelling < grade 1+ and limb symmetry on strength and hop tests >70 %.

CONCLUSION

Physiotherapists in Australia, France, and the Netherlands use many different return to running criteria and most of them use more than one criterion. Despite this, there was little consensus on the cut-off physiotherapists use to apply these criteria.

Bailout Options for Intra-operative Implant and Instrumentation Related Incidents and Complications During Arthroscopic Knee Surgery-A Retrospective Study

Background

Arthroscopic knee procedures are one amongst the common surgical interventions for problems in the knee. It is technically more demanding than an open procedure and is associated with several potential complications. During arthroscopy procedures, several technical challenges may arise, and even experienced surgeons may encounter new issues. However, careful attention to the surgical technique can help prevent or resolve them.

Methodology

The study was conducted on all patients who underwent knee arthroscopy procedure during study period. We recorded details of the implants used and any unexpected situations related to them, as well as how they were managed. Instrumentation-related parameters such as screwdriver issues, radiofrequency ablator issues, scope damages, shaver complications, probe complications, and meniscus suture passing devices were also assessed.

Results

In total, there were 12 (3.73%) implant and instrument-related incidents and complications, of which 5 (1.55%) were implant-related and 7 (2.17%) were instrument related. Among the instrumentation-related incidents and complications, two (0.62%) were screwdriver breakage incidents, two (0.62%) were radiofrequency ablator-related incidents, one was arthroscopic probe (0.31%) related incident, one (0.31%) was meniscus suture passing device related complication and one (0.31%) was arthroscope related incident.

Conclusion

Surgeons must be ready to anticipate and effectively manage any technical difficulties that may arise during the procedure, maintaining composure in the face of unexpected challenges and guiding the team. In most cases, incidents can be addressed intra operatively and may not have long-term effects on patient outcomes. It is crucial to have multiple implant and instrument backup options available for successful surgery.

Unicompartmental knee replacement combined with anterior cruciate ligament reconstruction provides comparable results to total knee replacement with no increased risk of complications

INTRODUCTION

There is controversy about the management of unicompartmental knee osteoarthritis (OA) in young, active patients with anterior cruciate ligament (ACL) insufficiency. This study compares the subjective, radiological, and functional results of total knee replacement (TKR) vs. combined medial unicompartmental knee replacement (UKR) with ACL reconstruction.

METHOD

Twelve patients suffering from medial OA and ACL deficiency with varus knee deformity and/or tibial slope <10° and absence of patellofemoral-related problems were eligible for combined UKR and ACL reconstruction (Group A). Twenty-six patients matched for age, male/female ratio and body mass index who received TKR in the same time frame were included as a control group (Group B). Oxford Knee Score (OKS), WOMAC index of osteoarthritis, Knee Osteoarthritis Outcome Score (KOOS), and routine X-rays were used for assessment.

RESULTS

Ten years after surgery, the mean overall KOOS score, OKS, WOMAC index increased from preoperatively, showing a statistically significant difference (p < 0.001). In terms of KOOS, OKS, or WOMAC scores at the most recent follow-up, there was no discernible difference between the groups (p = n.s.). Three years following surgery, one female patient in group A received revision TKR due to the lateral compartment's osteoarthritis developing and the patient's pain persisting. Concerning radiographic assessment, at the most recent follow-up (average 7.9 years in group A and 8.8 years in group B), there were no radiographic indications of implant loosening or proof of pathologic radiolucent lines.

CONCLUSIONS

UKR combined with ACL restoration offers clinical and radiographic outcomes comparable to TKR 10 years following surgery with no elevated risk of complications.

Bilateral movement asymmetries exist in recreational athletes during a 45° sidestep cut post-anterior cruciate ligament reconstruction

Individuals post-ACL reconstruction (ACLR) are at elevated risk for ACL re-injury. While several studies have examined biomechanical asymmetries post-ACLR during landing, less is known about asymmetries during a sidestep cut. Therefore, the purpose of this study was to compare sagittal and frontal plane biomechanics at the hip and knee during a 45° sidestep cut in post-ACLR participants and healthy controls. Nineteen athletes post-ACLR and nineteen healthy controls performed a bilateral 45° sidestep cut while three-dimensional kinematics and kinetics were measured. Sagittal and frontal plane kinematics and kinetics were examined at the hip and knee during stance phase. A linear mixed model compared biomechanical differences between the limbs of ACLR and healthy control participants (α = 0.05). In the post-ACLR group, peak hip extension, peak knee flexion, sagittal hip and knee excursion, and the peak knee extensor moment were significantly lower in the ACLR surgical limb compared to the non-surgical limb (p < 0.05). The peak knee flexion angle and peak knee extensor moment were also lower in the ACLR surgical limb compared to the matched control limb (p < 0.05). In summary, post-ACLR participants exhibited altered sagittal plane movement in their surgical limb that was not demonstrated in the non-surgical limb or in control participants, which may suggest avoidance, or reduced utilization of the ACLR limb.

Utility of three-dimensional proton density-weighted sequence MRI in knee for the assessment of Anterolateral complex in Anterior cruciate ligament injury

OBJECTIVES

To assess the proportion and pattern of injury of the anterolateral ligament (ALL) and the Kaplan fibre (KF) complex in knees with anterior cruciate ligament (ACL) injuries on MRI using three-dimensional (3D) proton density (PD) sequences.

METHODS

A total of 88 patients having ACL injury were included in this cross-sectional study. 3D PD sequences were used to assess injury of ALL and the KF complex and were graded on a scale of 0 to 3. MR images were evaluated by two radiologists. Interobserver agreement was determined using Cohen Kappa.

RESULTS

Femoral, meniscal, and tibial portions of ALL were visualized in 90.9%, 92%, and 94.3% of the study subjects, respectively. Proximal and distal KF were visualized in 92% and 93.2% of patients, respectively. Injury to ALL and KF was seen in 63.6% and 17% of the patients, respectively. Excellent interobserver agreement was noted for the identification and grading of ALL and KF complex injuries.

CONCLUSIONS

Oblique reformatted 3DPD MRI reliably detect ALC; however, ALL injury is better characterized than KF injury using this sequence.

ADVANCES IN KNOWLEDGE

Given the potential role of anterolateral complex (ALC) in maintaining the rotational stability of the knee, ALC assessment using the 3D PD sequences and their oblique reformatted images should be incorporated as routine review area of the knee MRI, particularly in the setting of ACL tear.

Revision ACL reconstruction in female athletes: current concepts

The challenge of revision anterior cruciate ligament (ACL) reconstruction lies in its complexity, varied presentation, and technical intricacies. A successful ACL reconstruction should allow patients to safely return to preinjury activities. However, it is only sometimes simple, and many risk factors and concurrent pathologies come into play. Evaluating and analysing the cause of failure and associated conditions is paramount to addressing them effectively. Despite a plethora of research and improvements in knowledge and technology, e gaps exist in issues such as optimal techniques of revision surgery, graft options, fixation, concurrent procedures, rehabilitation and protocol for return to sports of high-level athletes. Female athletes need additional focus since they are at higher risk of re-injury, suboptimal clinical outcomes, and lower rates of return to sport following revision reconstruction. Our understanding about injury prevention and the protection of ACL grafts in female athletes needs to be improved. This review focuses on the current state of revision ACL surgery in female athletes and provides recommendations and future directions for optimising outcomes in this high-risk group.

A review of Marcel Lemaire's original work on lateral extra-articular tenodesis

This classic discusses Marcel Lemaire's original publications in the context of modern surgical practice, including a description of his original lateral extra-articular tenodesis. Previously published in French, these translations shed light on his revelations regarding the anterior cruciate ligament's role in knee stability and his detailed insights into the ressaut rotatoire or the pivot shift phenomenon. We track the evolution of Lemaire's procedure since the publication of his original technique in 1967 which used a nylon cord superficial to the lateral collateral ligament followed by cast immobilisation for one month. We report his patient outcomes as he refines his methods through experiential learning. Lemaire's fundamental concepts in relation to anterior cruciate ligament deficiency remain relevant in contemporary clinical practice. Furthermore, the "modified Lemaire technique" has emerged as one of the preferred methods for lateral extra-articular tenodesis. We hope that disseminating his thoughts to a wider audience will help enlighten the ongoing debate regarding the management of rotatory instability. LEVEL OF EVIDENCE: V - Expert Opinion.

Influence of hamstring stiffness on anterior tibial translation after anterior cruciate ligament rupture

BACKGROUND

There is a correlation between the hamstring stiffness and the decrease of anterior tibial translation in athletic patients with healthy knees. This observation could question the clinical reliability of the Lachman-Trillat test to detect complete ACL ruptures in patients with an important hamstring stiffness. This study aims to determine if anterior tibial translation is correlated with hamstring stiffness in patients with complete ACL rupture.

METHODS

This is a prospective study including patients with unilateral complete ACL rupture confirmed by MRI. The arthrometer GNRB® was used to measure anterior tibial translation on both knees at 134 N and compute the side-to-side difference. The hamstring stiffness was assessed with the eccentric peak torque using the isokinetic dynamometer CON-TREX. Linear regressions were done between these two parameters on two study groups: one included all patients (GR1), and the other included only isolated ACL injuries without associated lesions (GR2).

RESULTS

Fifty-two patients were included (29 men, 23 women) with an average of 34.9 years old. The mean eccentric peak torque of the hamstrings for pathological knees was 94.9Nm for GR1 and 91.7Nm for GR2. The mean side-to-side difference was 2.42 mm for GR1 and 1.99 mm for GR2. No significant correlations were identified for GR1 (p = 0.66) and GR2 (p = 0.105).

CONCLUSION

No significant linear correlation was found between side-to-side difference measured by GNRB® and hamstring stiffness for pathological knees with complete ACL rupture. These results lead to believe that the Lachman-Trillat clinical test is not influenced by hamstring stiffness.

LEVEL OF EVIDENCE

Prospective study, level of evidence IV.

Independent data collectors decrease bias in the measurement of adherence to anterior cruciate ligament injury prevention programs

OBJECTIVES

Studies on adherence to neuromuscular training (NMT) for anterior cruciate ligament (ACL) injury prevention are frequently biased due to the use of self-reporting by coaches or the athletes themselves. Few NMT studies use data collectors (aside from the athletes or the individuals administering the NMT program) to decrease bias when assessing the adherence of coaches and sports teams. We hypothesized that the use of a data collector who is independent of the team to evaluate adherence to NMT programs would be reliable.

METHODS

In a prior a cluster-randomized controlled trial evaluating adherence to NMT training trial, twelve boys' and nine girls' high school athletic teams in a variety of sports were enrolled. Eight data collectors (unaffiliated with the NMT program) were hired specifically to record adherence of the athletes to the NMT exercises at each team's warm-ups 2-3 times a week, prior to practices and games. In addition to the data collectors, a control group of independent observers made visits throughout the season to also record adherence (solely for the purpose of this study, alongside the data collectors and in the same fashion) in order to evaluate the data collectors' performance and determine inter-observer reliability. The inter-observer reliability between data collectors and independent observers was measured using the Kappa statistic.

RESULTS

A total of 399 warm-ups for practices or games were observed by data collectors to obtain adherence data. Independent observers also measured adherence at 58 practices or games for inter-observer reliability. Exercise instruction and alignment cues for 29 different exercises were analysed. The Kappa values ranged from 0.63 to 1.0, indicating substantial to perfect agreement. The overall Kappa values of 0.89 and 0.90 for exercise instruction and alignment cues, respectively, indicated almost perfect agreement.

CONCLUSION

The use of a data collector who is independent of the team to evaluate adherence to NMT programs (rather than athlete or coach self-reporting), was shown to be a reliable method for measurement of adherence in studies of NMT for injury prevention. Avoiding self-reporting in adherence research to NMT training may decrease bias.

LEVEL OF EVIDENCE

I.

Effectiveness of the KC@H programme compared with clinic-based rehabilitation in patients recovering from ACL reconstruction: a study protocol for a single-centre, two-arm, single-blinded, randomised controlled superiority trial

Patients who cannot fully comply with conventional clinic-based rehabilitation (CR) sessions after ACL reconstruction (ACLR) may find additional internet-based sessions beneficial. These remote sessions include therapeutic exercises that can be done at home, potentially extending the reach of rehabilitation services to underserved areas, prolonging the duration of care and providing improved supervision. The study's main purpose is to determine if the Knee Care at Home (KC@H) programme is more effective than conventional CR alone in improving patient-reported, clinician-reported and physical functional performance outcome measures after ACLR. Additionally, the trial assesses the significance of changes in outcome measures for clinical practice. This protocol outlines a randomised controlled trial for postoperative recovery following ACLR. Adult participants of both sexes who meet specific criteria will be randomly assigned to either the CR group or the KC@H group. Only the latter group will receive internet-based sessions of therapeutic exercises at home and CR sessions. A follow-up evaluation will be conducted for both groups 12 weeks after the intervention ends. The trial protocol was approved by the Ethics Committee of the Universidade de Évora and complies with the Code of Ethics of the World Medical Association. All recordings will be stored on a secure server with limited access and deleted as soon as they are no longer needed. The KC@H programme is expected to be superior to conventional CR for patients recovering from ACLR across multiple outcome measures. Also, the programme has the potential to promote superior recovery and extend the reach and duration of care. Trial registration number: NCT05828355.

The effectiveness of the STOP-X training program on the knee valgus angle and balance in female basketball players with dynamic knee valgus: a randomized controlled trial

BACKGROUND

Dynamic knee valgus (DKV) accompanied by poor balance is the cause of anterior cruciate ligament (ACL) injury in athletes, and the identification and correction of these factors are always of interest to researchers. Therefore, the purpose of this research was to investigate the effect of the STOP-X program on the knee valgus angle and static and dynamic balance in female basketball players with DKV defects.

METHODS

The present study was a quasi-experimental study. Thirty female basketball players with DKV defects were purposefully identified by the single-leg landing (SLL) test and were randomly assigned to two control (n = 15) and experimental (n = 15) groups. Static balance status was evaluated with the BASS STICK test, and dynamic balance status was evaluated with the Y-balance test (YBT). The experimental group performed the STOP-X program for 25-40 min for eight weeks (three times per week), and the control group performed their traditional warm-up program. Data were analyzed by means of 2 × 2 repeated measures ANOVA followed by post hoc comparison (Bonferroni) at the significance level of (P < 0.05) with SPSS version 26.

RESULTS

The results showed that with the use of the STOP-X program, there was a significant difference between the experimental and control groups in variables of the static balance (F = 56.45; P = 0.001; ES = 0.66, PC=↑59.64%), total dynamic balance score (F = 107.57; P = 0.001; ES=↑0.79, PC=↑19.84%), and knee valgus angle (F = 119.46; P = 0.001; ES = 0.81, PC=↓34.36%).

CONCLUSION

In addition to reducing the knee valgus angle, applying the STOP-X injury prevention program can improve static and dynamic balance in female basketball players with DKV defects. Therefore, it can be recommended that sports trainers benefit from these advantages by adding STOP-X training to routine basketball exercises.

Overexpression of manganese superoxide dismutase mitigates ACL injury-induced muscle atrophy, weakness and oxidative damage

Oxidative stress has been implicated in the etiology of skeletal muscle weakness following joint injury. We investigated longitudinal patient muscle samples following knee injury (anterior cruciate ligament tear). Following injury, transcriptomic analysis revealed downregulation of mitochondrial metabolism-related gene networks, which were supported by reduced mitochondrial respiratory flux rates. Additionally, enrichment of reactive oxygen species (ROS)-related pathways were upregulated in muscle following knee injury, and further investigation unveiled marked oxidative damage in a progressive manner following injury and surgical reconstruction. We then investigated whether antioxidant protection is effective in preventing muscle atrophy and weakness after knee injury in mice that overexpress Mn-superoxide dismutase (MnSOD+/-). MnSOD+/- mice showed attenuated oxidative damage, atrophy, and muscle weakness compared to wild type littermate controls following ACL transection surgery. Taken together, our results indicate that ROS-related damage is a causative mechanism of muscle dysfunction after knee injury, and that mitochondrial antioxidant protection may hold promise as a therapeutic target to prevent weakness and development of disability.

All-epiphyseal anterior cruciate ligament reconstruction yields superior sports performances than the trans-epiphyseal technique in skeletally immature patients: a systematic review

BACKGROUND

Anterior cruciate ligament (ACL) tears in skeletally immature patients are increasingly common. Evidence comparing the outcomes of all-epiphyseal versus trans-epiphyseal ACL reconstruction in skeletally immature patients is limited, and the current literature could benefit from a comprehensive systematic review. The present study compared all-epiphyseal versus trans-epiphyseal ACL reconstruction in skeletally immature patients. The outcomes of interest were to compare joint laxity, patient-reported outcome measures (PROMs), return to sport, and complications.

METHODS

This study was conducted according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. In November 2023, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. No additional filters were used in the database search. All the clinical studies investigating ACL reconstruction in skeletally immature patients were accessed. Only articles that clearly stated the surgical technique (all- or trans-epiphyseal) were eligible. Only articles with a minimum of 6 months of follow-up were included. Only articles that clearly stated that surgeries were conducted in children with open physis were eligible.

RESULTS

Data from 1489 patients (1493 procedures) were collected, of which 32% (490 of 1489 patients) were female. The mean length of follow-up was 46.6 months. The mean age of the patients was 12.7 years. No difference was found in joint laxity (Table 3): positive pivot shift (P = 0.4), positive Lachman test (P = 0.3), and mean arthrometer laxity (P = 0.1). No difference was found in PROMs (Table 4): International Knee Documentation Committee (IKDC) (P = 0.3), Lysholm (P = 0.4), and Tegner (P = 0.7). The trans-epiphyseal technique was associated with a greater rate of patients unable to return to sports (1% versus 7%, P = 0.0001) and with a longer time to return to sports (7.7 versus 8.6 months, P = 0.01). Though the trans-epiphyseal technique was associated with a lower rate of return to sport, this difference was not statistically significant (P = 0.8). No difference was evidenced in the rate of patients who had reduced their league or level of sports activity (P = 0.6) or in the rate of patients who had returned to their previous league or level of sports activity (P = 0.7). No difference was found in the rate of complication: re-tear (P = 0.8), reoperation (P = 0.7), increased laxity (P = 0.9), and persistent instability sensation (P = 0.3).

CONCLUSION

Trans-epiphyseal ACL reconstruction was associated with a greater rate of patients unable to return to sport and with a longer time to return to sport compared with the all-epiphyseal technique in skeletally immature patients. Level of evidence Level III, systematic review.

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.

Comparison of stiffness, elasticity and resilience values of ACL with autografts used instead of ACL in terms of texture analysis

Background

Anterior cruciate ligament (ACL) ruptures are one of the most extensively studied injuries in the field of orthopedics, but despite the extensive research, graft selection for ACL reconstruction remains a matter of debate. The present study aims to evaluate the stiffness and elasticity of native ACLs using texture profile analysis and compare results with those of autografts used in ACL reconstruction.

Methods

Included in the study were dissected 12 cadavers from which grafts were recovered. The graft characteristics, such as stiffness, elasticity and resilience, were measured using a TA.XT Plus Texture Analyzer.

Findings

Among the grafts studied, Achilles' tendon graft (0.70; 0.64) had the highest resilience in both males and females, while the greatest elasticity was identified in the patellar tendon graft (Male: 93 %; Female: 94 %) in all subjects. The highest stiffness value in males was recorded for the quadriceps tendon graft (2928.76 N), while the highest stiffness value in females was recorded for Achilles' tendon graft (2204.61 N).

Interpretation

According to the study data, the autografts that may be considered as an alternative to ACL were, listed in order of strength from high to low, the quadriceps, Achilles', patella and hamstring tendons in men, and the Achilles', quadriceps, patellar and hamstring tendons in women. It is worthy of note that the hamstring tendon graft, which is the most frequently preferred autograft in ACL reconstruction, was found to be the lowest in all parameters in both groups.

Comparison of physical therapy utilization, timing of return-to-sport test completion, and hop test performance by age and between sexes in youth athletes after anterior cruciate ligament reconstruction

OBJECTIVE

To compare physical therapy (PT) utilization, timing of return-to-sport (RTS) test and hop test performance by age and between sexes in youth after anterior cruciate ligament reconstruction (ACLR).

DESIGN

Multicenter retrospective cohort.

METHODS

A retrospective review of adolescents after primary ACLR was conducted. Participants completed return-to-sport (RTS) tests including single-legged hop testing. PT frequency, average weekly visits, and timing of RTS test were calculated. T-tests assessed the effect of age and sex on average weekly PT visits and multivariable logistic regressions assessed odds of passing hop tests.

RESULTS

289 participants were included (15.7 ± 1.9 years). There was no difference in average weekly PT visits (p = 0.321) or time to RTS test (p = 0.162) by age. There were significant differences in average weekly PT visits (p = 0.047) and mean time from surgery to RTS test (p = 0.048) between sexes with small effect sizes (d = 0.24 and d = 0.21, respectively). Age and sex had no effect on odds of passing hop tests (OR, 1.29; 95% CI, 0.71-2.35 and OR, 0.79; 95%CI, 0.43-1.45, respectively).

CONCLUSION

In a youth cohort, age and sex may have no clinically important effect on PT visit utilization, timing of RTS test or hop test performance.

Study on the use of 3D printed guides in the individualized reconstruction of the anterior cruciate ligament

OBJECTIVE

Evaluation of the accuracy and effectiveness of 3D printed guides to assist femoral tunnel preparation in individualised reconstruction of the anterior cruciate ligament.

METHODS

Sixty patients who attended the Affiliated Hospital of Binzhou Medical College for autologous hamstring single bundle reconstruction of the anterior cruciate ligament from October 2018 to October 2020 were selected and randomly divided into two groups, including 31 cases in the 3D printing group (14 males and 17 females, mean age 41.94 ± 10.15 years) and 29 cases in the control group (13 males and 16 females, mean age 37.76 ± 10.34 years). Patients in both groups were assessed for intraoperative femoral tunnel accuracy, the number of intraoperative positioning and the time taken to prepare the femoral tunnel, the length of the anteromedial approach incision, the pre-planned bone tunnel length and intraoperative bone tunnel length in the 3D printed group, IKDC score and Lysholm score preoperatively and at 3, 6 and 12 months postoperatively, the Lachman、pivot-shift test preoperatively and at 6 months postoperatively, gait analysis to assess internal and external rotation in flexion of the knee at 12 months postoperatively and postoperative complications in both groups.

RESULTS

There was no statistical difference in functional knee scores and anteromedial approach incision length between the 3D printed and control groups (p > 0.05), while there was a statistical difference in the accuracy of tunnel positioning, the time taken to prepare the femoral bone tunnel and the degree of external rotation of the knee in flexion between the two groups (p < 0.05). There was no statistical difference between the preoperative planning of the bone tunnel length and the intraoperative bone tunnel length (p > 0.05).

COMPLICATIONS

One case in the 3D printing group developed intermuscular vein thrombosis in the affected lower limb after surgery, which disappeared after treatment, while three cases in the control group developed intermuscular vein thrombosis in the affected lower limb. No complications such as bone tunnel rupture, deep vein thrombosis in the lower limb and infection occurred in either group.

CONCLUSION

3D printed guides assisted with individualized ACL reconstruction may improve the accuracy of femoral tunnel positioning, which is safe and effective, while reducing the operative time and the number of intraoperative positioning, without increasing the length of incision, and may obtain higher functional scores and rotational stability of the knee joint, which is in line with the concept of individualized ACL reconstruction.

4 Domain Sports PROM in Spanish: Cross-cultural adaptation in the Chilean population and reliability analysis

BACKGROUND

Patient-Reported Outcome Measures (PROMs) are tools of increasing interest in the sports population. The purpose of this study was to perform the cross-cultural adaptation and reliability analysis of the 4 Domain Sports Patient-Reported Outcome Measure (4DSP) into Spanish.

METHODS

A six-stage cross-cultural adaptation protocol was executed to obtain the Spanish version of the 4DSP (S-4DSP). Subsequently, the questionnaire was administered to a population of 108 postoperative athletes with ACL (Anterior Cruciate Ligament) injuries. The questionnaire was administered again after 30 days. Acceptability, floor and ceiling effects, internal consistency (Cronbach's alpha), and reproducibility (Intraclass Correlation) were evaluated.

RESULTS

The S-4DSP was fully completed by 108 participants (mean age 34 ± 10.75, 26% women), achieving 100% acceptability. No floor effect was detected. The statistical analysis yielded a global Cronbach's alpha for the questionnaire of 0.65, and domain-specific alphas of 0.88, 0.72, 0.27, and 0.68 for the first, second, third, and fourth domains, respectively. The Intraclass Correlation test reached a maximum of 0.94 and a minimum of 0.48 for the first and fifth questions, respectively.

CONCLUSIONS

The S-4DSP is a reliable and useful tool for evaluating Spanish-speaking athletes after ACL reconstruction.

Small Intercondylar Notch Size Is Not Associated with Poor Surgical Outcomes of Anatomical Single-Bundle Anterior Cruciate Ligament Reconstructions

Background

Although many studies have been conducted on the association between the intercondylar notch size and the risk of anterior cruciate ligament (ACL) injury, few studies have examined its relationship with the condition after surgical treatment. Therefore, this study aimed to investigate the surgical outcomes of anatomical single-bundle ACL reconstruction according to intercondylar notch volumes.

Methods

Medical records of patients who underwent anatomical single-bundle ACL reconstruction using a tibialis anterior allograft between 2015 and 2019 were retrospectively reviewed. For each sex, eligible patients were classified into two groups based on their percentile of intercondylar notch volumes, which were measured using postoperative three-dimensional computed tomography images (group S, ≤ 50th percentile of included patients; group L, > 50th percentile of included patients). Additional grouping was performed based on the group's percentiles of normalized values of intercondylar notch volumes to body heights. Between-group comparative analyses were performed on the perioperative data and surgical outcomes in both objective and subjective aspects.

Results

One hundred patients were included in the study. For male patients, there were no differences in the overall surgical outcomes between groups, whereas group L showed a significantly greater knee anteroposterior (AP) laxity than group S at the final follow-up (p = 0.042 for the side-to-side differences [SSD] at the maximum manual force). Similarly, there were no differences in the female patients in the overall surgical results between the groups, whereas group L showed a significantly greater knee AP laxity at the final follow-up (p = 0.020 for the SSD at 134 N; p = 0.011 for the SSD at the maximum manual force). Additional analyses based on the normalized values of the intercondylar notch volume showed consistent results for male patients, and additional grouping for female patients was identical to the existing grouping.

Conclusions

The surgical outcomes of anatomical single-bundle ACL reconstruction in patients with relatively small intercondylar notch volumes were comparable to those with large notch volumes, but rather showed favorable outcomes in postoperative knee AP laxity.

The influence of jump-landing direction on dynamic postural stability following anterior cruciate ligament reconstruction

BACKGROUND

Traditional testing prior to return to sport following anterior cruciate ligament reconstruction typically involves jump-landing tasks in the forward direction. As injury is most likely the result of multiplanar neuromuscular control deficits, assessment of dynamic postural stability using landing tasks that require multiplanar stabilization may be more appropriate. The purpose of this study was to examine how dynamic postural stability is affected when performing jump-landing tasks in three different directions.

METHODS

Fifteen athletes [11 females (18.0 ± 3.0 years) and 4 males (18.5 ± 3.1 years)] following anterior cruciate ligament reconstruction performed a series of single-limb jump-landing tasks in 3 directions. Individual directional stability indices and a composite dynamic postural stability index were calculated using ground reaction force data and were compared using separate one-way repeated measures ANOVAs.

FINDINGS

All directional stability indices demonstrated a significant main effect for jump-landing direction (medial-lateral P < 0.001, η2p = 0.95; anterior-posterior P < 0.001, η2p = 0.97; vertical P = 0.021, η2p = 0.24). The diagonal jump-landing direction produced increased medial-lateral stability and vertical stability scores, while the forward and diagonal jump-landing directions produced increased anterior-posterior stability scores. There was no significant effect for the composite dynamic stability index score.

INTERPRETATION

Jump-landing direction affects dynamic postural stability in all 3 planes of movement in athletes following anterior cruciate ligament reconstruction. Results indicate the potential need to incorporate multiple jump-landing directions to better assess dynamic postural stability prior to return to sport.

3D visualization of the human anterior cruciate ligament combining micro-CT and histological analysis

PURPOSE

The study aimed to obtain a comprehensive 3D visualization of knee specimens, including the cruciate ligaments and corresponding femoral and tibial bone insertions using a non-destructive micro-CT method.

METHODS

Knee specimens were fixed in anatomical positions and chemically dehydrated before being scanned using micro-CT with a voxel size of 17.5 μm. RGBA (red, green, blue, alpha) transfer functions were applied to virtually colorize each structure. Following micro-CT scanning, the samples were rehydrated, decalcified, and trimmed based on micro-CT 3D reconstructions as references. Histological evaluations were performed on the trimmed samples. Histological and micro-CT images were registered to morphologically and densitometrically assess the 4-layer insertion of the ACL into the bone.

RESULTS

The output of the micro-CT images of the knee in extension and flexion allowed a clear differentiation of the morphologies of both soft and hard tissues, such as the ACL, femoral and tibial bones, and cartilage, and the subsequent creation of 3D composite models useful for accurately tracing the entire morphology of the ligament, including its fiber and bundle components, the trajectory between the femur and tibia, and the size, extension, and morphology of its insertions into the bones.

CONCLUSION

The implementation of the non-destructive micro-CT method allowed complete visualization of all the different components of the knee specimens. This allowed correlative imaging by micro-CT and histology, accurate planning of histological sections, and virtual anatomical and microstructural analysis. The micro-CT approach provided an unprecedented 3D level of detail, offering a viable means to study ACL anatomy.

Prevention of knee stiffness following ligament reconstruction: Understanding the role of Arthrogenic Muscle Inhibition (AMI)

The knee is a joint that is often injured in sport, with a large and increasing number of ligament tears and repairs; postoperative complications can lead to poor outcome, such as stiffness. Beyond the well-known and well-described intra- and extra-articular causes of postoperative stiffness, the present study introduces the concept of a central reflex motor inhibition mechanism called arthrogenic muscle inhibition (AMI). AMI occurs after trauma and can be defined as active knee extension deficit due to central impairment of Vastus Medialis Obliquus (VMO) contraction, often associated with spinal reflex hamstring contracture. This explains the post-traumatic flexion contracture that is so common after knee sprain. The clinical presentation of AMI is easy to detect in consultation, in 4 grades from simple VMO inhibition to fixed flexion contracture by posterior capsule retraction in chronic cases. After recent anterior cruciate ligament (ACL) tear, more than 55% of patients show AMI, reducible in 80% of cases by simple targeted exercises initiated in consultation. Practically, in patients who have sustained knee sprain, it is essential to screen for this reflex mechanism and assess reducibility, as AMI greatly aggravates the risk of postoperative stiffness. In case of hemarthrosis, we recommend joint aspiration, which provides immediate benefit in terms of pain and motor inhibition. In case of persistent AMI, classical electrostimulation and "cushion crush", as used by all physiotherapists, are ineffective. To reduce the risk of postoperative stiffness, no surgery should be considered until AMI has resolved. LEVEL OF EVIDENCE: expert opinion.

A new magnetic resonance imaging grading system for anterior cruciate ligament myxoid degeneration in osteoarthritis of the knee

BACKGROUND

This study aimed to investigate association between magnetic resonance imaging (MRI) and histological findings of degenerated anterior cruciate ligament (ACL) in knee osteoarthritis (OA), and based on this result, to develop a new ACL degeneration grading system by MRI that corresponds to histological findings of degenerated ACL.

HYPOTHESIS

MRI signal intensity of the ACL could correspond to histological findings of collagen degeneration.

PATIENTS AND METHODS

A collection of 106 ACL specimens from 85 patients who underwent primary total knee arthroplasty was investigated for signal intensity of the ACL and muscle on axial Fat-saturated proton density-weighted MRI and MRI signal intensity ratio (ACL/muscle) was calculated. The correlation between ACL histological degeneration and MRI ACL/muscle signal intensity ratio was analyzed. The ACL was stratified into 3 grades based on signal intensity relative to muscle intensity (grade 1, low; grade 2, iso; and grade 3, high), and the extent to ACL degeneration in each MRI ACL degeneration grade was evaluated.

RESULTS

Collagen degeneration (53.5±24.0%) and myxoid change (25.2±18.8%) in degenerated ACL significantly correlated with MRI signal intensity ratio of the ACL/muscle (r=0.62, p<0.0001; r=0.67, p<0.0001). ACL were assigned to grade 1 (n=22 [20.8%]), grade 2 (n=56 [52.8%]), and grade 3 (n=28 [26.4%]). ACL collagen degeneration was 34.8±18.4% in grade 1, 49.3±21.7% in grade 2, and 76.6±12.0% in grade 3. ACL myxoid change was 10.0±11.3% in grade 1, 21.3±14.1% in grade 2, and 45.0±15.3% in grade 3.

DISCUSSION

The ACL/muscle signal intensity ratio on MRI correlated with the extent to ACL myxoid degeneration. The new MRI ACL degeneration grade is helpful to estimate the extent to ACL myxoid degeneration in knee OA.

LEVEL OF EVIDENCE

III; retrospective cohort study.

Prospective study of functional outcomes and return to sports after anterior cruciate ligament reconstruction in the knee

PURPOSE

Individual factors of low rates of return to sport after anterior cruciate ligament (ACL) reconstruction were unclear. We evaluated the impact of various individual factors after ACL reconstruction for return to sport in athletes.

METHODS

A prospective study was performed in 1274 athletes, who had undergone ACL autograft reconstruction. Individual factors survey about return to sport was performed during the second year after surgery. Athlete responses were analyzed with a multivariate logistic model adjusted for baseline patient characteristics and an adjusted Cox model.

RESULTS

Younger age and involvement in higher-level sporting activities were associated with a significantly higher frequency and a significantly shorter time to return to sport (running, training, competition; p = 0.001 to 0.028). Men returned to sport more rapidly than women, for both training (p = 0.007) and competition (p = 0.042). Although there was no difference to return to sport between hamstring (HT) and patellar tendon (PT) autograft. We note that MacFL surgery (Mac Intosh modified with intra- and extra-articular autografts used the tensor fasciae latae muscle) was associated with a higher frequency (p = 0.03) and rapidity (p = 0.025) of return to training than HT. Sports people practicing no weight-bearing sports returned to training (p < 0.001) and competition (p < 0.001) more rapidly than other sports people. By contrast, the practicing pivoting sports with contact started running again sooner (p < 0.001).

CONCLUSION

Younger age, male sex, higher level of sports, sportspeople practicing no weight-bearing sports, and MacFL surgery reduce time to return to sport after ACL reconstruction.