Proprioception in the anterior cruciate deficient knee

Does proprioceptive training improve joint function and psychological readiness in patients after anterior cruciate ligament reconstruction? A randomized controlled trial

INTRODUCTION

A decrease in proprioceptive sensation occurs after anterior cruciate ligament reconstruction (ACLR). However, there is relatively little research on proprioceptive rehabilitation, compared with studies on muscle strength and range of motion (ROM). The purpose of this study was to assess the effect of supplementing a traditional rehabilitation program with proprioceptive training in ACLR patients to improve knee function, psychological readiness, pain and dynamic balance in the early postoperative period.

METHODS

This was a randomized, parallel-group, controlled trial in which 48 patients were enrolled in either proprioceptive group (n = 24) or control group (n = 24) from the first week up to 12 th weeks of the operation. Participants in the control group received a traditional ACLR rehabilitation program, while the proprioceptive group received additional proprioceptive training in addition to the traditional ACLR rehabilitation program. The outcome measures included the International Knee Documentation Committee (IKDC), the ACL Return to Sport After Injury scale (ACL-RSI), the visual analog scale (VAS), and the Y-Balance Test before and after surgery.

RESULTS

We found that, at 12 weeks post-surgery, patients in the proprioceptive group had significantly higher IKDC scores compared to those in the control group (74.8 ± 4.3 vs 71.6 ± 5.2, P = 0.04). At the 12 th week, the ACL-RSI score of patients in the proprioceptive group was greater than that of the control group (68.2 ± 9.2 vs 62.8 ± 8.2, P = 0.04). The Y balance comprehensive index (YBCI) in the proprioceptive group of patients was greater than that in the control group (94.5% ± 3.3% vs 91.5% ± 4.1%, P = 0.01) at 12 weeks after surgery. No statistically significant differences in the VAS score were found between the two groups.

CONCLUSIONS

Proprioceptive training is superior to conventional training in terms of knee function, psychological readiness and dynamic balance 12 weeks after ACL reconstruction surgery, but has no statistically significant effect on pain.

TRIAL REGISTRATION

(Chinese Clinical Trial Registry ( https://www.chictr.org.cn ), No. ChiCTR2400087631, 7/31/2024).

Immunohistochemical Investigation of Mechanoreceptors Within the Injured Scapholunate Ligament

PURPOSE

Scapholunate ligaments (SLLs) play a well-established role in maintaining carpal alignment and kinematics, and are innervated with sensory mechanoreceptors located within the ligaments. They are involved in the afferent arc of dynamic wrist stability. The aim of this study was to describe the changes in these mechanoreceptor populations in injured SLLs.

METHODS

Injured SLLs were collected from human wrists at the time of SLL reconstruction or limited wrist fusion, where the ligament remnants would otherwise be discarded. These specimens were formalin-fixed and paraffin-embedded for immunohistochemical analysis to identify mechanoreceptors, which were then classified by type and location within the ligament.

RESULTS

A total of 15 ligaments were collected, with the interval from injury ranging from 39 days-20 years. Eleven ligaments were collected less than one year after injury, and four ligaments were collected two years or more after injury. A total of 66 mechanoreceptors were identified, with 50 mechanoreceptors identified in nine of the 11 specimens collected less than one year after injury. In this group, 54% of the mechanoreceptors resided in the volar subunit, 20% in the dorsal subunit, and 26% in the proximal subunit. Two of the four specimens collected two years or later after injury contained mechanoreceptors, all of which were located in the dorsal subunit. Increasing time from injury demonstrated a decline in mechanoreceptor numbers within the volar subunit.

CONCLUSIONS

Mechanoreceptors were consistently located in the SLL, particularly in the volar subunit of specimens collected less than one year after injury.

CLINICAL RELEVANCE

Ligament reconstruction techniques aim to primarily reconstitute the biomechanical function of the disrupted SLL; however, re-establishing the afferent proprioceptive capacity of the SLL may be a secondary objective. This suggests the need to consider the reconstruction of its volar subunit particularly in those managed within one year of injury.

Mesenchymal Stem Cell Exosome and Fibrin Sealant Composite Enhances Rabbit Anterior Cruciate Ligament Repair

BACKGROUND

The anterior cruciate ligament (ACL) fails to heal after rupture, leading to joint instability and an increased risk of osteoarthritis. Mesenchymal stem/stromal cell (MSC) exosomes have reported wide-ranging therapeutic efficacy; however, their potential for augmenting ACL repair remains to be investigated.

PURPOSE

To evaluate the use of MSC exosomes with fibrin sealant on biological augmentation of ACL healing after suture repair and their effects on ACL fibroblast functions.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve rabbit knees underwent ACL transection and suture repair. MSC exosome and fibrin composite (Exosome+Fibrin) or fibrin (Fibrin) alone was used to supplement the suture repair in 6 knees. ACL repair was assessed by magnetic resonance imaging at 6 and 12 weeks postoperatively and by histologic and immunohistochemical analyses at 12 weeks. To investigate the mechanisms through which MSC exosomes augment ACL repair, metabolic activity, proliferation, migration, and matrix synthesis assays were performed using the primary ACL fibroblasts. RNA sequencing was also performed to assess global gene expression changes in exosome-treated ACL fibroblasts.

RESULTS

Based on magnetic resonance imaging findings, 5 of 6 Exosome+Fibrin-treated ACLs were completely or partially healed, as opposed to 5 of 6 Fibrin-treated ACLs appearing torn at 6 and 12 weeks postoperatively. Additionally, 4 of 6 Exosome+Fibrin-treated ACLs were isointense, as compared with 5 of 6 Fibrin-treated ACLs that were hyperintense, indicating improved remodeling and maturation of the repaired ACLs with Exosome+Fibrin treatment. Histologically, Exosome+Fibrin-treated ACLs showed more organized collagen fibers and abundant collagen deposition, with a high amount of collagen I and relatively lower amount of collagen III, which are consistent with the matrix structure and composition of the normal ACL. Cell culture studies using ACL fibroblasts showed that MSC exosomes enhanced proliferation, migration, and collagen synthesis and deposition, which are cellular processes relevant to ACL repair. Further gene set enrichment analysis revealed key pathways mediated by MSC exosomes in enhancing proliferation and migration while reducing matrix degradation of ACL fibroblasts.

CONCLUSION

The combination of MSC exosomes and fibrin sealant (Exosome+Fibrin) applied to a suture repair enhanced the morphologic and histologic properties of the ACL in a rabbit model, and these improvements could be attributed to the augmented functions of ACL fibroblasts with exosome treatment.

CLINICAL RELEVANCE

This work supports the use of MSC exosomes in biological augmentation of ACL healing after suture repair.

A comparative analysis of autograft choices of anterior cruciate ligament reconstruction and their effects on muscle strength and joint biomechanics

Introduction

Anterior cruciate ligament reconstruction (ACLR) is crucial to restore knee stability and function after ACL injuries, especially in physically active individuals. Despite advances in surgical techniques and rehabilitation protocols, the choice of autograft has a significant impact on postoperative recovery, particularly on muscle strength and joint biomechanics. In this study, the effects of four autografts are investigated: Iliotibial band (ITB), combined ITB and hamstring tendon (ITB + HT), hamstring tendon (HT) and bone-tendon-bone (BTB) on quadriceps and hamstring peak torque (QPT and HPT) recovery and hamstring to quadriceps ratio (H:Q) to assess knee stability and function.

Methods

Forty-two active males (mean ± standard deviation of age: 31.5 ± 6.1 years, height: 177 ± 6 cm, weight: 76 ± 11 kg, body mass index: 24.5 ± 2.2 kg/m²) with primary ACL ruptures were allocated to the four graft groups (ITB: n = 16, ITB + HT: n = 12, HT: n = 7, BTB: n = 7) and underwent a standardized rehabilitation protocol. Quadriceps and hamstring peak torque (QPT and HPT, respectively) as indicators of isokinetic muscle strength were assessed both postoperatively and follow-up after approximately six months (mean 6.29 ± 1.70 months).

Results

Significant differences in QPT and HPT recovery between the healthy and injured legs were found in all graft groups (P < 0.001). The BTB group showed the largest QPT deficit between healthy and injured legs (Δ = 133.4 Nm, Cohen's d = 8.05) and HPT deficit (Δ = 41.1 Nm, Cohen's d = 4.01). In contrast, the ITB + HT group showed the smallest deficits in QPT (Δ = 22.5 Nm, Cohen's d = 0.73) and HPT (Δ = 13.5 Nm, Cohen's d = 1.21). The BTB group also showed the largest deviation in H:Q ratios (Δ = -0.23, Cohen's d = 2.70), while the HT group showed a more balanced recovery with smaller significant deficits in H:Q ratios (Δ = -0.07, Cohen's d = 0.46).

Conclusion

The BTB graft showed the most pronounced variations in QPT and HPT between healthy and injured legs in the short term, indicating the importance of longitudinally monitoring knee stability to determine the best autograft choice for ACLR. While all graft types contribute to muscle strength recovery, the HT graft may provide advantages in balancing muscle strength and potentially enhancing knee stability.

Longitudinal assessment of knee joint proprioception using weight-bearing and non-weight-bearing tests throughout rehabilitation after anterior cruciate ligament reconstruction

OBJECTIVE

Evaluate active knee joint position sense (JPS) throughout rehabilitation after anterior cruciate ligament reconstruction (ACLR).

DESIGN

Longitudinal.

SETTING

Motion laboratory.

PARTICIPANTS

Twenty-two individuals post-ACLR and 22 activity-matched non-injured controls performed weight-bearing and non-weight-bearing knee JPS tests. The ACLR participants performed at three functional timepoints: T1, able to perform single-leg sit-to-stand; T2, able to hop maximally; T3, cleared for return to sports. Controls performed on one occasion.

MAIN OUTCOME MEASURES

Constant, absolute, variable errors (CE, AE, VE) and interlimb symmetry estimates (100% signifying perfect symmetry), for 40° and 65° knee flexion target angles.

RESULTS

For the weight-bearing 40° condition, CE and AE of the ACLR knee significantly increased from T1 to T2 (P = 0.010) and T1 to T3 (P = 0.002). Consequently, interlimb asymmetry for AE significantly increased from T1 (AEsym% = 101.2% ± 55.4%) to T3 (AEsym% = 139.7% ± 54.8%). Compared to controls, AE for the ACLR knee was significantly smaller at T1 (P = 0.016). No other significant differences were observed.

CONCLUSIONS

Smaller JPS errors at early rehabilitation while weight-bearing may have been due to heightened quadriceps activation and increased γ motor neuron sensitivity, compensating for deficient ACL mechanoreceptors. In contrast, non-weight-bearing testing did not reveal changes over time. Clinicians are advised to consider these distinctions when assessing proprioception at different rehabilitation stages.

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

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

The effectiveness of fatigue on repositioning sense of lower extremities: systematic review and meta-analysis

INTRODUCTION

An injury can significantly harm both individual and team performance. One of the most important risk factors for sports-related injuries, especially non-collision injuries, is fatigue. It seems that poor proprioception may play an essential role to impose athletes to further injuries. This systematic review and meta-analysis aimed to examine the effectiveness of fatigue on the repositioning sense of the lower extremity joints.

METHOD

The electronic databases, including PubMed, Web of Science, Scopus, and Google Scholar were systematically searched from inception to 11January 2024. The obtained records were exported to the EndNote Software version 8. Then, two investigators examined the records independently to find eligible studies based on the inclusion/exclusion criteria. In the case of disagreements, a consequence method was utilized. The quality of the eligible studies was evaluated using the Downs and Black checklist. Comprehensive Meta-Analysis (CMA) software ver. 3 software was used for statistical analysis. Q-test and I2 were employed to examine the data homogeneity. In addition, considering the risk of bias, the Funnel Plot and trim-and-fill method were used.

RESULTS

After reviewing the titles and abstracts of 3883 studies found in the selected databases, 43 articles were found to be eligible to include in meta-analyses. The results showed that fatigue led to a significant increase in the active absolute error of the knee (SDM = 0.524, 95% CI = 0.406-0.841), ankle in the horizontal plane (SDM = 0.541, 95% CI = 0.367-0.715), ankle in the sagittal plane (SDM = 0.443, 95% CI = 0.088-0.798), and hip (SDM = 0.988, 95% CI = 0.135-1.841). However, fatigue had no significant effects on the passive absolute error of the knee and ankle in horizontal plane and relative angular error of the knee.

CONCLUSION

Fatigue can diminish the active joint position sense of the lower extremities and thus may increase the risk of injury by reducing proprioception. Therefore, future research could be conducted to investigate the potential impact of integrated fatigue-mitigating exercises into athletes' training programs, with the aim of reducing the incidence of sports-related injuries.

The Impact of Differential Knee Laxity on Brain Activation During Passive Knee Joint Loading

Although higher anterior knee laxity is an established risk factor of ACL injury, underlying mechanisms are uncertain. While decreased proprioception and altered movement patterns in individuals with anterior knee laxity have been identified, the potential impact of higher laxity on brain activity is not well understood. Thus, the purpose of this study is to identify the impact of different magnitudes of knee laxity on brain function during anterior knee joint loading. Twenty-seven healthy and active female college students without any previous severe lower leg injuries volunteered for this study. Anterior knee laxity was measured using a knee arthrometer KT-2000 to assign participants to a higher laxity (N=15) or relatively lower laxity group (N=12). Functional magnetic resonance images were obtained during passive anterior knee joint loading in a task-based design using a 3T MRI scanner. Higher knee laxity individuals demonstrated diminished cortical activation in the left superior parietal lobe during passive anterior knee joint loading. Less brain activation in the regions associated with awareness of bodily movements in females with higher knee laxity may indicate a possible connection between brain activity and knee laxity. The results of this study may help researchers and clinicians develop effective rehabilitation programs for individuals with increased knee laxity. This article is protected by copyright. All rights reserved.

Spontaneous healing of acute ACL ruptures: rate, prognostic factors and short-term outcome

INTRODUCTION

Anterior cruciate ligament (ACL) reconstruction is considered the first line treatment in ACL rupture. However, some patients return to high intensity sport activities and show a normal knee function without ACL reconstruction. Therefore, aim of this study was to evaluate the rate and prognostic factors of spontaneous healing in patients with ACL rupture and the short-term functional outcome.

METHODS

The rate, prognostic factors and short-term functional results of spontaneous healing in patients with ACL rupture were evaluated in 381 patients. Morphology of ACL rupture and extent of posterior tibial slope (PTS) were classified by MR- and x-ray imaging. In patients with normal knee stability in anesthesia examination and healed ACL during the arthroscopy 6 weeks after trauma ACL reconstruction was canceled. IKDC -, Tegner Activity Score, KT 1000 testing and radiological characteristics were collected 12 months postoperatively in these patients.

RESULTS

14.17% of the patients with ACL rupture showed a spontaneous healing after 6 weeks. Femoral ACL-rupture (p < 0.02) with integrity of ligament stump > 50% (p < 0.001), without bundle separation (p < 0.001) and decreased PTS (p < 0.001) was found significantly more often in patients with a spontaneous healed ACL. The average IKDC score was high at 84,63 in patients with healed ACL at 1 year follow-up, but KT 1000 testing was inferior compared to non-injured side.

CONCLUSION

Spontaneous healing of a ruptured ACL happened in 14% of the patients. Especially in low-demand patients with femoral single bundle lesions without increased posterior tibial slope delayed ACL surgery should be considered to await the possibility for potential spontaneous ACL healing.

A prospective study of joint position sense after anterior cruciate ligament injury, reconstruction with a bone-patella tendon-bone graft, and rehabilitation

BACKGROUND

Disruption of the anterior cruciate ligament (ACL) is associated with significant biomechanical and neuromuscular changes including deficits in joint proprioception. While previous studies have assessed joint position sense (JPS) in ACL deficient knees, methods have varied and few have done so with prospective study designs. The specific aim of this investigation was to determine the effect(s) of ACL reconstruction and recovery time may have on JPS.

METHODS

In this prospective study, we assess the effects of ACL reconstruction and rehabilitation on joint position sense in a temporal study. Twelve patients with unilateral ACL injuries were assessed pre-operatively and at 2, 4, 8 months post-op. JPS measurements were performed, while the subject was standing, with passive-active (P-A) and active-active (A-A) tests. Comparisons between the injured/reconstructed and contralateral, uninjured knee were evaluated in terms of real and absolute mean errors.

RESULTS

There were no statistically significant differences between the injured/reconstructed and contralateral/normal side with P-A or A-A testing at 2, 4, or 8 months.

CONCLUSION

We conclude that there is no difference in joint position sense between the injured and contralateral leg after ACL disruption and reconstruction beginning as early as 2 months post-op. This study provides further evidence that knee proprioception is not altered by ACL injury and reconstruction.

LEVEL OF EVIDENCE

II.

The Relationship between Lower Extremity Functional Performance and Balance after Anterior Cruciate Ligament Reconstruction: Results of Patients Treated with the Modified All-Inside Technique

BACKGROUND AND OBJECTIVES

Anterior cruciate ligament (ACL) ruptures are common injuries, and ACL reconstruction (ACLR) is among the most common surgical procedures in sports surgery. Our research aims to compare the 6-month post-operative results of the modified all-inside (MAI) ACLR technique, single leg hop tests (SLHT), and Y balance tests applied in different directions on the operated and non-operated sides.

MATERIALS AND METHODS

A retrospective cohort of 22 male recreational athletes who underwent MAI ACLR techniques performed by the same surgeon were evaluated. The functional knee strengths of the participants on the operated and non-operated sides were evaluated with five different tests of SLHTs: single hop for distance (SH), triple hop for distance (TH), crossover triple hop for distance (CH), medial side triple hop for distance (MSTH), and medial rotation (90°) with hop for distance (MRH). Their dynamic balance was evaluated with the Y balance Test.

RESULTS

Compared to pre-operative levels, there was a significant improvement in the mean Lysholm, Tegner, and IKDC scores during the post-operative period (p < 0.05). There was a difference between SH, THD, CHD, MSTH, and MRH on the operated and non-operative sides (p < 0.05). There was no difference between Y balance scores on the operated and non-operative sides, and there were no differences between LSI scores resulting from SLHTs (p > 0.05). There were no significant relationships between YBT (composite scores) and SH, TH, CH, MSTH, and MRH distances in the healthy leg (p > 0.05), but a significant correlation with only CH in the ACL leg (p < 0.05).

CONCLUSIONS

Our research shows that sixth-month post-operative SLHT findings were lower on the ACL side compared to the healthy side in patients tested with the MAI ACLR technique. However, when these scores are evaluated in terms of balance, it can be seen that both sides reveal similar findings. The similarity of LSIs in SLHTs applied in different directions, and balance scores of ACL and healthy sides revealed that the MAI technique is also an ACLR technique that can be used in athletes from a functional point of view.

Changes in Dynamic Postural Stability After ACL Reconstruction: Results Over 2 Years of Follow-up

Background:

The anterior cruciate ligament (ACL) is crucial for knee proprioception and postural stability. While ACL reconstruction (ACLR) and rehabilitation improve postural stability, the timing in improvement of dynamic postural stability after ACLR remains relatively unknown.

Purpose:

To evaluate changes in dynamic postural stability after ACLR out to 24 months postoperatively.

Study Design:

Case series; Level of evidence, 4.

Methods:

Patients undergoing ACLR were prospectively enrolled, and dynamic postural stability was assessed within 2 days before surgery, at 3-month intervals postoperatively to 18 months, then at 24 months. Measurements were made on a multidirectional platform tracking the patient’s center of mass based on pelvic motion. The amount of time the patient was able to stay on the platform was recorded, and a dynamic motion analysis score, reflecting the patient’s ability to maintain one’s center of mass, was generated overall and in 6 independent planes of motion.

Results:

A total of 44 patients with a mean age of 19.7 ± 6.2 years completed the study protocol. Overall mean dynamic postural stability improved significantly at 3, 6, 9, and 12 months after surgery, with continued improvement out to 24 months. Notable improvements occurred in medial/lateral and anterior/posterior stability from baseline to 6 months postoperatively, while internal/external rotation and flexion/extension stability declined initially after surgery from baseline to 3 months postoperatively before stabilizing to the end of the study period.

Conclusion:

Overall dynamic postural stability significantly improved up to 12 months after ACLR. Improvement in postural stability occurred primarily in the medial/lateral and anterior/posterior planes of motion, with initial decreases in the flexion/extension and internal/external rotational planes of motion.

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

BACKGROUND

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

HYPOTHESIS

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

IV, systematic review.

Properties of tests for knee joint threshold to detect passive motion following anterior cruciate ligament injury: a systematic review and meta-analysis

BACKGROUND

Threshold to detect passive motion (TTDPM) tests of the knee joint are commonly implemented among individuals with anterior cruciate ligament (ACL) injury to assess proprioceptive acuity. Their psychometric properties (PMPs), i.e. reliability, validity and responsiveness, are however unclear. This systematic review aimed to establish the PMPs of existing knee joint TTDPM tests among individuals with ACL injury.

METHODS

The databases PubMed, AMED, CINAHL, SPORTDiscus, Web of Science, Scopus, CENTRAL and ProQuest were searched to identify studies that assessed the properties of knee joint TTDPM tests in individuals with ACL injury. The risk of bias for each included study was assessed at the outcome level for each test. Overall quality and levels of evidence for each property were rated according to established criteria. Meta-analyses with mean differences were conducted using random-effects models when adequate data were available.

RESULTS

Fifty-one studies covering 108 TTDPM tests and 1632 individuals with unilateral ACL injury were included. A moderate-to-strong level of evidence indicated insufficient quality for all of the following: convergent validity, known-groups validity, discriminative validity, responsiveness between subgroups, and responsiveness to intervention. Subgroup meta-analyses for known-groups validity did however find that a starting angle of 15° resulted in significantly worse TTDPM for knees with ACL injury compared to those of asymptomatic persons (mean difference 0.28°; 95% CI 0.03 to 0.53; P = 0.03), albeit based on only three studies. Due to the lack of evidence, it was not possible to estimate the quality of reliability, measurement error, and criterion validity, nor responsiveness from a criterion and construct approach.

CONCLUSIONS

Among persons with ACL injury, existing tests of knee joint TTDPM lack either sufficient quality or evidence for their reliability, validity and responsiveness. Significantly worse thresholds for ACL-injured knees compared to those of asymptomatic controls from a 15° starting angle and trends towards significance for some validity measures nevertheless encourage the development of standardised tests. Further research investigating the influence of modifiable test components (e.g. starting angle and motion direction) on the PMPs of knee joint TTDPM tests following ACL injury is warranted.

Platelet-rich plasma pretreatment protects anterior cruciate ligament fibroblasts correlated with PI3K-Akt-mTOR pathway under hypoxia condition

Background

/Objective: Biological factors such as platelet-rich plasma (PRP) combined with anterior cruciate ligament (ACL) primary repair technology are used to treat ACL injury. However, the protective mechanism of PRP for ACL fibroblasts under hypoxia condition is still unknown. The aim of this study was to investigate the protective effect of PRP on ACL fibroblasts under hypoxia condition and illustrate the mechanism of PRP regulating the ACL fibroblasts under hypoxia condition.

Methods

The cells were divided into three groups: control group, hypoxia group and PRP pretreatment group. Lethal dose (LD) 50 for hypoxia induction time and the maximum efficacy of PRP concentration were confirmed by CCK-8 assay. The ability of cell apoptosis, cell proliferation, and cell migration were tested by flow cytometry, scratch assay and transwell assay, respectively. Extracellular matrix (ECM) synthesis and hypoxia-inducible factor 1α (HIF-1α) were identified by immunofluorescence staining, Masson's staining and transmission electron microscope analysis. Inflammatory cell infiltration was assessed by hematoxylin and eosin staining as well as immunofluorescence staining. Western blot analysis and real-time PCR were performed to assess the associated gene and protein expression, respectively. The ratio of phosphorylated/total PI3K, Akt and mTOR were also assessed by western blot analysis.

Results

① LD 50 of hypoxia was 48 ​h and the maximum efficacy of PRP concentration was 600 ​× ​10⁹/L. ② ANNEXIN V-FITC/PI flow cytometry showed that the hypoxia condition significantly increased the apoptosis of cells (P ​< ​0.001) whereas PRP pretreatment significantly decreased the apoptosis of cells under hypoxia (P ​< ​0.001). The expressions of gene and protein of Bax, Bcl-2, cleaved-caspase 3 were consistent with the results of flow cytometric analysis. ③ Cell cycle analysis for flow cytometry showed the inhibitory effect of hypoxia and promotive effect of PRP pretreatment. ④ Immunofluorescence staining (HIF-1α, collagen I and III) showed the positive effect of hypoxia and negative effect of PRP on these parameters. Real-time PCR showed that type I and III collagen were 2.1 folds and 2.5 folds higher after 48 ​h hypoxia induction compared to the control group. PRP pretreatment significantly reduced the type I and III collagen mRNA expression of the hypoxia induced ACL fibroblasts to 78.5% and 77.7% at 48 ​h compared to hypoxia group (P ​< ​0.001), respectively.⑤ Cell migration assay showed that hypoxia condition significantly restrained cell migration compared with the control group. PRP could alleviate the inhibitory effect of hypoxia on fibroblasts. ⑥ Western blot analysis showed the ratio of phosphorylated/total PI3K, Akt and mTOR in hypoxia group increased to 31%, 20% and 44/% compared to control group, respectively. ⑦ The results of in vivo analysis was in accordance with the results of in vitro analysis.

Conclusion

PRP can protect ACL fibroblasts via decreasing apoptosis and increasing cell viability, cell migration and cell proliferation under hypoxia condition. And such PRP protective effect was correlated with PI3K/Akt/mTOR pathway.

The translational potential of this article

PRP can be used to treat patients with ACL tear by injection under arthroscopy or ultrasound guiding.

Proprioceptive and Clinical Outcomes after Remnant Preserved Anterior Cruciate Ligament Reconstruction: Assessment with Minimal Confounding Factors

Objective

To evaluate the proprioceptive and clinical function of the knee joint after anterior cruciate ligament reconstruction (ACLR) with various amounts of remnant preserved with as few confounding factors as possible.

Methods

This retrospective study included 46 patients who underwent ACLR with remnant preservation between March 2013 and February 2019. These patients had less than 6 months injury‐to‐surgery interval and no concomitant injuries. The researchers divided these subjects into two groups based on the length of the remnant preserved after ACLR, with group A defined as having more than 1/3 of the original length preserved and group B defined as less than 1/3 of the original length preserved. Clinical scores were obtained using the Lysholm knee scoring scale and the Tegner activity scale. The Lysholm score was calculated preoperatively, at 3, 6, and 12 months postoperatively, and at the last follow up. The Tegner score was calculated preoperatively, at 12 months postoperatively and at the last follow up. Anterior laxity was measured using the KT2000 arthrometer preoperatively and at 12 months postoperatively. Proprioceptive function was evaluated through reproduction of passive positioning (RPP) and threshold to detection of passive motion (TDPM). Both RPP and TDPM were measured at the angle of 15° at 3, 6, and 12 months postoperatively. Unpaired t‐tests were performed to investigate the difference in each parameters between the two groups.

Results

In the present study, 20 patients were classified into group A and 26 into group B. All patients were followed up for an average of 34.70 ± 12.79 months. All 46 patients were satisfied with the outcome of the surgery and no complications were reported at the end of the study. No significant differences were found between the two groups in terms of the Lysholm score and anterior laxity by KT2000 at all time points. The Tegner score was significantly higher in group A at 12 months postoperatively and at the final follow‐up. In addition, group A's RPP was significantly better than that of group B's when tested at the angles of 15° and 30° at 3 months postoperatively, and at the angle of 15° at 6 months postoperatively. Group A's TDPM was also significantly better than that of group B's at all three tested angles at 3 months postoperatively, and at the angle of 15° at 6 months postoperatively.

Conclusion

Patients with ACLR with more than 1/3 of the original length preserved demonstrated a higher activity level 12 months postoperatively and better proprioceptive function at 15° of extension at 3 and 6 months postoperatively.

Knee Valgus during Jump Landing Is Related to the Inaccuracy of Knee Position Recognition in Healthy Young Women

Objective:

Knee valgus during jump landing is a cause of knee injuries during sports activities. Body recognition is important for maintaining the knees and other body parts in their proper positions. The aim of this study was to investigate whether knee valgus during jump landing in healthy young women is related to the inaccuracy of recognition of bilateral knee positions in the squatting position.

Methods:

In 39 healthy young women, the degree of knee valgus was evaluated during the drop vertical jump test using the ratio of the knee separation distance to the ankle separation distance. The accuracy of recognition of bilateral knee positions in the squatting position was evaluated by having the blindfolded subjects indicate with their index fingers the subjective positions of their bilateral patellae by placing their fingers on a horizontal bar positioned in front of them 3 cm below the navel. The difference ratio of the recognized distance to the actual distance between the bilateral patellae was measured as an inaccuracy index.

Results:

The degree of knee valgus during the drop vertical jump test was positively correlated with the degree of inaccuracy of the recognized knee position with the knees in the neutral position (r=0.358, P=0.025).

Conclusions:

In healthy young women, knee valgus during jump landing was significantly correlated with the inaccuracy in knee position recognition in the squatting posture. This finding suggests that the assessment of knee position recognition in the squatting position could be useful as a screening tool for preventing knee injuries on jump landing during sports activities.

Efficacy of wrist robot-aided orthopedic rehabilitation: a randomized controlled trial

Background

In recent years, many studies focused on the use of robotic devices for both the assessment and the neuro-motor reeducation of upper limb in subjects after stroke, spinal cord injuries or affected by neurological disorders. Contrarily, it is still hard to find examples of robot-aided assessment and rehabilitation after traumatic injuries in the orthopedic field. However, those benefits related to the use of robotic devices are expected also in orthopedic functional reeducation.

Methods

After a wrist injury occurred at their workplace, wrist functionality of twenty-three subjects was evaluated through a robot-based assessment and clinical measures (Patient Rated Wrist Evaluation, Jebsen-Taylor and Jamar Test), before and after a 3-week long rehabilitative treatment. Subjects were randomized in two groups: while the control group (n = 13) underwent a traditional rehabilitative protocol, the experimental group (n = 10) was treated replacing traditional exercises with robot-aided ones.

Results

Functionality, assessed through the function subscale of PRWE scale, improved in both groups (experimental p = 0.016; control p < 0.001) and was comparable between groups, both pre (U = 45.5, p = 0.355) and post (U = 47, p = 0.597) treatment. Additionally, even though groups’ performance during the robotic assessment was comparable before the treatment (U = 36, p = 0.077), after rehabilitation the experimental group presented better results than the control one (U = 26, p = 0.015).

Conclusions

This work can be considered a starting point for introducing the use of robotic devices in the orthopedic field. The robot-aided rehabilitative treatment was effective and comparable to the traditional one. Preserving efficacy and safety conditions, a systematic use of these devices could lead to decrease human therapists’ effort, increase repeatability and accuracy of assessments, and promote subject’s engagement and voluntary participation. Trial Registration ClinicalTrial.gov ID: NCT04739644. Registered on February 4, 2021—Retrospectively registered, https://www.clinicaltrials.gov/ct2/show/study/NCT04739644.

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

Introduction

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

Methods

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

Results

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

Conclusion

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

Wrist Position Sense in Two Dimensions: Between-Hand Symmetry and Anisotropic Accuracy Across the Space

A deep investigation of proprioceptive processes is necessary to understand the relationship between sensory afferent inputs and motor outcomes. In this work, we investigate whether and how perception of wrist position is influenced by the direction along which the movement occurs. Most previous studies have tested Joint Position Sense (JPS) through 1 degree of freedom (DoF) wrist movements, such as flexion/extension (FE) or radial/ulnar deviation (RUD). However, the wrist joint has 3-DoF and many activities of daily living produce combined movements, requiring at least 2-DoF wrist coordination. For this reason, in this study, target positions involved movement directions that combined wrist flexion or extension with radial or ulnar deviation. The chosen task was a robot-aided Joint Position Matching (JPM), in which blindfolded participants actively reproduced a previously passively assumed target joint configuration. The JPM performance of 20 healthy participants was quantified through measures of accuracy and precision, in terms of both perceived target direction and distance along each direction of movement. Twelve different directions of movement were selected and both hands tested. The left and right hand led to comparable results, both target extents and directions were differently perceived according to the target direction on the FE/RUD space. Moreover, during 2-DoF combined movements, subjects' perception of directions was impaired when compared to 1-DoF target movements. In summary, our results showed that human perception of wrist position on the FE/RUD space is symmetric between hands but not isotropic among movement directions.

Decreased passive muscle stiffness of vastus medialis is associated with poorer quadriceps strength and knee function after anterior cruciate ligament reconstruction

BACKGROUND

Muscle deficits of the quadriceps and hamstrings are common after anterior cruciate ligament reconstruction, and increase the risk of knee reinjury. Muscle stiffness is an important factor for dynamic joint stability. However, the changes in quadriceps and hamstring muscle stiffness and its influence after anterior cruciate ligament reconstruction remain unclear.

METHOD

Twenty-five male subjects with anterior cruciate ligament reconstruction and twenty-one matched healthy subjects participated in this study. The passive muscle stiffness of the quadriceps and hamstrings was assessed by shear modulus using ultrasound shear wave elastography. The isokinetic muscle strengths of the quadriceps and hamstrings were tested. Knee function was evaluated by the International Knee Documentation Committee and Lysholm score. Muscle stiffness was compared between limbs via non-parametric tests. Correlation analysis was used to detect the relationship between muscle stiffness, isokinetic muscle strength and knee functional scores.

FINDINGS

The involved limb exhibited significantly decreased shear modulus in the vastus medialis compared to the dominant limbs(z = -3.585;P = 0.001;ES = 1.13) and non-dominant limbs(z = -3.551;P = 0.002;ES = 1.24) of healthy controls. The shear modulus of ST was also significantly lower in the involved limb when compared with the contralateral limbs(z = -3.996;P < 0.001;ES = 1.33), dominant limbs(z = -4.477;P < 0.001;ES = 1.65) and non-dominant limbs(z = -4.234;P = 0.001;ES = 1.43) of healthy controls. The shear modulus of the vastus medialis was associated with quadriceps peak torque at 60°/s(r = 0.470; p < 0.001) and knee functional score(r = 0.459; p = 0.021).

INTERPRETATION

The passive muscle stiffness of the vastus medialis decreased after anterior cruciate ligament reconstruction, which is associated with poorer quadriceps strength and knee function. The effect of modulation of muscle stiffness on improving knee function warrants future investigation.

Efficacy of Nonaugmented, Static Augmented, and Dynamic Augmented Suture Repair of the Ruptured Anterior Cruciate Ligament: A Systematic Review of the Literature

BACKGROUND

Anterior cruciate ligament suture repair (ACLSR) was abandoned late last century in favor of anterior cruciate ligament (ACL) reconstruction (ACLR) because of overall disappointing results. However, in recent years there has been renewed and increasing interest in ACLSR for treatment of ACL ruptures. Several contemporary ACLSR techniques are being used, but any difference in effectiveness is unclear.

HYPOTHESIS

Contemporary nonaugmented (NA), static augmented (SA), and dynamic augmented (DA) ACLSR leads to (1) comparable outcomes overall and (2) comparable outcomes between proximal third, middle third, and combined ACL rupture locations (a) within and (b) between ACLSR technique categories.

STUDY DESIGN

Systematic review.

METHODS

An electronic search was performed in the MEDLINE and Embase databases for the period between January 1, 2010, and August 7, 2019. All articles describing clinical and patient-reported outcomes for ACLSR were identified and included, and outcomes for NA, SA, and DA ACLSR categories were compared.

RESULTS

A total of 31 articles and 2422 patients were included. The majority of articles (65%) and patients (89%) reported outcomes of DA ACLSR. Overall, there was high heterogeneity in study characteristics and level as well as quality of evidence (19 level 4; 7 level 3; 3 level 2; and 2 level 1). Most studies indicated excellent patient-reported outcomes. Overall, the variability in (and the maximum of) the reported failure rate was high within all ACLSR categories. The variability in (and the maximum of) the reported rate of all other complications was highest for DA ACLSR. Regarding ACL rupture location, the failure rate was highest in proximal ACL ruptures within the SA and DA ACLSR categories; rates of all other reported complications were highest in combined ACL ruptures within the DA ACLSR category. However, no studies in the NA category and only 1 study in the SA ACLSR category evaluated combined ACL ruptures. The majority of studies comparing ACLSR and ACLR found no differences in outcomes.

CONCLUSION

The amount of high-quality evidence for contemporary ACLSR is poor. This makes it difficult to interpret differences among ACLSR categories and among ACL rupture locations and, though promising, to establish the role of ACLSR in the treatment of ACL ruptures. More high-quality large randomized clinical trials with longer follow-up comparing ACLSR and ACLR are needed.

Ultrasound Features of Skeletal Muscle Can Predict Kinematics of Upcoming Lower-Limb Motion

Seamless integration of lower-limb assistive devices with the human body requires an intuitive human-machine interface, which would benefit from predicting the intent of individuals in advance of the upcoming motion. Ultrasound imaging was recently introduced as an intuitive sensing interface. The objective of the present study was to investigate the predictability of joint kinematics using ultrasound features of the rectus femoris muscle during a non-weight-bearing knee extension/flexion. Motion prediction accuracy was evaluated in 67 ms increments, up to 600 ms in time. Statistical analysis was used to evaluate the feasibility of motion prediction, and the linear mixed-effects model was used to determine a prediction time window where the joint angle prediction error is barely perceivable by the sample population, hence clinically reliable. Surprisingly, statistical tests revealed that the prediction accuracy of the joint angle was more sensitive to temporal shifts than the accuracy of the joint angular velocity prediction. Overall, predictability of the upcoming joint kinematics using ultrasound features of skeletal muscle was confirmed, and a time window for a statistically and clinically reliable prediction was found between 133 and 142 ms. A reliable prediction of user intent may provide the time needed for processing, control planning, and actuation of the assistive devices at critical points during ambulation, contributing to the intuitive behavior of lower-limb assistive devices.

Decreased Postural Control in Patients Undergoing Anterior Cruciate Ligament Reconstruction Compared to Healthy Controls

CONTEXT

Patients with anterior cruciate ligament (ACL) tears are likely to have deficient dynamic postural stability compared with healthy sex- and age-matched controls.

OBJECTIVES

To test the hypothesis that patients undergoing ACL reconstruction have decreased dynamic postural stability compared with matched healthy controls.

DESIGN

Prospective case-control study.

SETTING

Orthopedic sports medicine and physical therapy clinics.

PATIENTS OR OTHER PARTICIPANTS

Patients aged 20 years and younger with an ACL tear scheduled for reconstruction were enrolled prospectively. Controls were recruited from local high schools and colleges via flyers.

INTERVENTIONS

Patients underwent double-stance dynamic postural stability testing prior to surgery, recording time to failure and dynamic motion analysis (DMA) scores. Patients were then matched with healthy controls.

MAIN OUTCOME MEASURES

Demographics, time to failure, and DMA scores were compared between groups.

RESULTS

A total of 19 females and 12 males with ACL tears were matched with controls. Individuals with ACL tears were more active (Marx activity score: 15.7 [1.0] vs 10.8 [4.9], P < .001); had shorter times until test failure (84.4 [15.8] vs 99.5 [14.5] s, P < .001); and had higher (worse) DMA scores (627 [147] vs 481 [132], P < .001), indicating less dynamic postural stability. Six patients with ACL deficiency (1 male and 5 females) demonstrated lower (better) DMA scores than their controls, and another 7 (4 males and 3 females) were within 20% of controls.

CONCLUSIONS

Patients undergoing ACL reconstruction had worse global dynamic postural stability compared with well-matched controls. This may represent the effect of the ACL injury or preexisting deficits that contributed to the injury itself. These differences should be studied further to evaluate their relevance to ACL injury risk, rehabilitation, and return to play.

Preservation of the Tibial Remnant in Anterior Cruciate Ligament Reconstruction May Improve Postoperative Proprioceptive Function

The purpose of this study was to retrospectively compare clinical results, including proprioceptive function, after anterior cruciate ligament (ACL) reconstruction between 2 groups using techniques that preserve and eliminate the tibial remnant. Forty-eight patients who were followed for at least 24 months after ACL reconstruction with 4-strand hamstring tendon autografts were enrolled in this study. They were then divided into 2 groups: the remnant-preserving group (group A, 26 patients), in whom more than 7 mm of the remnant tibial stump (approximately 20% of the mean length of the ACL) was preserved; and the remnant-eliminating group (group B, 22 patients), in whom the tibial remnant was eliminated during ACL reconstruction. The average duration of follow-up was 25.5 months. At last follow-up, patients were evaluated using the International Knee Documentation Committee scale, Hospital for Special Surgery score, Lachman test, arthrometer, reproduction of passive positioning (RPP) test, threshold to detection of passive motion (TTDPM) test, one-leg hop test, and single-limb standing test. The clinical results between the 2 groups were statistically compared. Group A showed significantly better results on the RPP test at 15° (P=.040) and 30° (P=.010), one-leg hop test (P=.017), and single-limb standing test (P=.007) compared with group B. The other results showed no significant differences. The remnant-preserving technique in ACL reconstruction yields better proprioceptive and functional outcomes and may help achieve postoperative patient satisfaction. [Orthopedics. 2020;43(4):e231-e236.].

Proprioception deficiency in articular cartilage lesions of the knee

Purpose

The purpose of this study is to investigate the proprioceptive function of patients with isolated articular cartilage lesions of the knee as compared to normal controls.

Methods

The Cartilage group consisted of eight subjects with radiologically and arthroscopically confirmed, isolated, unilateral, articular cartilage lesions of the knee (Outerbridge grade III or IV). They were compared to 50 normal controls. Knee proprioception was assessed by dynamic postural stabilometry using the Biodex Balance SD System. Patient-reported outcome measures (PROMs) were used to evaluate all subjects.

Results

Proprioception of the injured knee of the Cartilage group was significantly poorer compared to that of the control group (p < 0.001). A significant proprioceptive deficit also was observed when the uninjured knees of the Cartilage group were compared to those in the Control group (p = 0.003). There was no significant proprioceptive difference between the injured and the contra-lateral uninjured knee of the Cartilage group (p = 0.116). A significant correlation was found between the proprioception measurements of the injured and uninjured knee of the Cartilage group (r = 0.76, p = 0.030). A significant difference was observed in all PROMs (p < 0.001) between the Cartilage and Control groups.

Conclusions

Patients with isolated articular cartilage lesions of the knee had a significant proprioceptive deficit as compared to normal controls. The deficiency was profound and even affected the proprioceptive function of the contra-lateral uninjured knee. This study has shown that articular cartilage lesions have a major influence on knee proprioception. However, it remains uncertain as to whether a proprioceptive deficit leads to osteoarthritis or is a consequence of it.

Neural activity for hip-knee control in those with anterior cruciate ligament reconstruction: A task-based functional connectivity analysis

Anterior cruciate ligament injury may induce neurophysiological changes for sensorimotor control. Neuroimaging investigations have revealed unique brain activity patterns for knee movement following injury, indicating potential neural mechanisms underlying aberrant neuromuscular control that may contribute to heightened risk of secondary injury, altered movement patterns and poor patient outcomes. However, neuroimaging paradigms thus far have been limited to single joint, single motion knee tasks. Therefore, we sought to overcome prior limitations to understand the effects of injury on neural control of lower extremity movement by employing a multi-joint motor paradigm and determining differences in neural activity between ACL-reconstructed (ACLr) individuals relative to healthy matched controls. Fifteen patients with left anterior cruciate ligament reconstruction and fifteen matched healthy controls participated in this study. Neural activity was examined using functional magnetic resonance imaging during a block-designed knee-hip movement paradigm (similar to a supine heel-slide). Participants for each group were monitored and task performance was controlled via a metronome to ensure the same spatial-temporal parameters. We observed that those with ACL reconstruction displayed increased activation within the intracalcarine cortex, lingual gyrus, occipital fusiform gyrus, lateral occipital cortex, angular gyrus, and superior parietal lobule relative to controls. A follow-up task-based functional connectivity analyses using seed regions identified from the group analysis revealed connectivity among fronto-insular-temporal and sensorimotor regions within the ACLr participants. The results of this fMRI investigation suggest ACLr individuals require increased activity and connectivity in areas responsible for visual-spatial cognition and orientation, and attention for hip and knee motor control.

Anterior Cruciate Ligament Repair Using a Knotless Suture Implant

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

Functional Brain Plasticity Associated with ACL Injury: A Scoping Review of Current Evidence

Anterior cruciate ligament (ACL) injury is a common problem with consequences ranging from chronic joint instability to early development of osteoarthritis. Recent studies suggest that changes in brain activity (i.e., functional neuroplasticity) may be related to ACL injury. The purpose of this article is to summarize the available evidence of functional brain plasticity after an ACL injury. A scoping review was conducted following the guidelines of the Joanna Briggs Institute and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The terms "brain," "activity," "neuroplasticity," "ACL," "injury," and "reconstruction" were used in an electronic search of articles in PubMed, PEDro, CINAHL, and SPORTDiscus databases. Eligible studies included the following criteria: (a) population with ACL injury, (b) a measure of brain activity, and (c) a comparison to the ACL-injured limb (contralateral leg or healthy controls). The search yielded 184 articles from which 24 were included in this review. The effect size of differences in brain activity ranged from small (0.05, ACL-injured vs. noninjured limbs) to large (4.07, ACL-injured vs. healthy control). Moreover, heterogeneity was observed in the methods used to measure brain activity and in the characteristics of the participants included. In conclusion, the evidence summarized in this scoping review supports the notion of functional neuroplastic changes in people with ACL injury. The techniques used to measure brain activity and the presence of possible confounders, as identified and reported in this review, should be considered in future research to increase the level of evidence for functional neuroplasticity following ACL injury.

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

BACKGROUND

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Isokinetic knee strength and proprioception before and after anterior cruciate ligament reconstruction: A comparison between home-based and supervised rehabilitation

BACKGROUND

Rehabilitation after anterior cruciate ligament (ACL) reconstruction focuses on restoring knee deficiencies and function. However, the extent of the clinician's direct supervision that is required to recover knee function is unknown.

OBJECTIVE

To investigate differences in isokinetic knee strength improvement, endurance, and proprioception between home-based (HBR) and supervised rehabilitation (SR).

METHODS

Thirty participants were randomly allocated to each group after reconstruction. Isokinetic knee strength and proprioception were measured using the Biodex multi-joint and stability systems, respectively, before and after intervention.

RESULTS

The SR group showed a significant improvement from baseline, but not the HBR group (SR group, from 1.94 ± 1.44 to 1.02 ± 0.92, p< 0.05; HBR group, from 1.69 ± 0.88 to 1.61 ± 0.90, p> 0.05). There was a significant effect of exercise type on proprioception scores after controlling for pretest values (p< 0.05). No significant difference in isokinetic knee strength was observed between the groups.

CONCLUSIONS

HBR recovered knee strength as effectively as the SR, but SR was more effective than HBR for the recovery of proprioception and functional knee movement. This result indicates that guidance from health professionals play an important role in enhancing proprioception for patients following ACL reconstruction.

Motor imagery in high-functioning individuals with chronic anterior cruciate ligament deficiency: A cross-sectional study

BACKGROUND

There is increasing evidence that motor imagery performance (MIP) is impaired in conditions that have a component of movement dysfunction. However, MIP has not been investigated in people with chronic anterior cruciate ligament (ACL) deficiency who experience limited disability and function at high levels.

HYPOTHESIS

This study had three objectives: (1) to assess implicit MIP in individuals with a chronic ACL deficient (ACLD) knee compared with healthy controls (i.e., intact anterior cruciate ligament); (2) to determine if the location of ACL deficiency affects MIP (dominant versus non-dominant leg); and (3) to determine if impairment in MIP is specific to the side (injured versus non-injured) of ACL deficiency.

METHODS

Forty-five participants with chronic ACLD knee and 44 healthy controls completed a left/right judgement task of pictured knees using the "Recognise" app to evaluate implicit MIP. Accuracy and reaction time of judgements were compared between groups. Additionally, within the chronic ACLD knee group, we made comparisons between the dominant ACLD knee and non-dominant ACLD knee subgroups and between the injured knee and the non-injured knee of the ACLD group.

RESULTS

There were no differences in implicit MIP between the ACLD knee and the control group, the non-injured knee versus injured knee of the ACLD knee group, or the dominant ACLD knee versus non-dominant ACLD knee subgroups.

CONCLUSION

Implicit MIP is not disrupted in high functioning individuals with chronic ACLD knee.

Hypoesthesia after anterior cruciate ligament reconstruction: The relationship between proprioception and vibration perception deficits in individuals greater than one year post-surgery

BACKGROUND

While surgical reconstruction restores mechanical stability following anterior cruciate ligament (ACL) rupture, many experience early-onset osteoarthritis despite surgery. Neurophysiological changes are hypothesized to contribute to knee osteoarthritis progression. Proprioceptive deficits have been reported following ACL injury/reconstruction; however, vibration perception threshold (VPT) has been less studied. This study explored relationships between pain, VPT, proprioception, function, and strength following ACL-reconstruction.

METHODS

Twenty individuals (27 ± 6 years; 10 males) (standard deviation) status-post ACL-reconstruction were compared with a control group. Measurements included VPT, proprioception (threshold to detect passive movement), pain, function (Knee Outcome Survey (KOS)) and isometric quadriceps strength. Group differences were assessed using Mann-Whitney U tests, side-to-side differences with Wilcoxon Signed Rank tests, and associations evaluated using Spearman correlations.

RESULTS

The ACL-reconstruction group had minor functional deficits (15 ± 11%) and resting pain (1.8 ± 1.7). Impaired VPT and proprioception (hypoesthesia) were demonstrated on surgical compared to contralateral and control limbs (p ≤ 0.008). Proprioception was significantly different between contralateral and control knees, but not VPT. Surgical knee proprioceptive deficits and VPT deficits were positively correlated (ρ = 0.462, p = 0.047) but not in controls (ρ = -0.042, p = 0.862). Strength was negatively correlated to pain (ρ = -0.589; p = 0.006), but not to KOS scores, proprioception or VPT (p ≥ 0.099).

CONCLUSION

Proprioceptive deficits following ACL injury have been ascribed to loss of afferent input from the torn ligament. Alternatively, multi-modality as well as contralateral sensory deficits suggest a spinal/supraspinal source of neurophysiological findings which may predispose to early osteoarthritis.

LEVEL OF EVIDENCE

III.

Effects of isokinetic muscle strengthening on balance, proprioception, and physical function in bilateral knee osteoarthritis patients with moderate fall risk

OBJECTIVES

This study aims to assess the effects of isokinetic quadriceps and hamstring strengthening exercises on balance, proprioception, and physical function in patients with moderate-to-severe knee osteoarthritis and moderate fall risk.

PATIENTS AND METHODS

Between November 2011 and December 2012, a total of 39 participants (30 females, 9 males; mean age 61.7±8.6 years; range, 18 to 79 years) with Grade 2 or 3 knee osteoarthritis according to the Kellgren-Lawrence radiographic grading system and moderate risk of fall with active knee pain were included in this study. All participants received isokinetic quadriceps and hamstring strengthening exercises for six weeks. Pre-treatment quadriceps and hamstring muscle strength (peak torque and total work value) and quadriceps to hamstring muscle strength ratio at angular velocities of 60°/sec and 180°/sec, range of motion (ROM), average proprioceptive errors at 15-45° and 30-60°, the Berg Balance Scale (BBS) scores, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscale scores, the Visual Analog Scale (VAS) scores, and physical function tests results were compared with the post-treatment results. The correlations of pre- and post-treatment BBS and average proprioceptive error at 15-45° and 30-60° changes to other pre- and post-treatment clinical measurements changes were calculated.

RESULTS

Post-treatment quadriceps and hamstring muscle strength at angular velocities of 60°/sec and 180°/sec and quadriceps to hamstring muscle strength ratios at angular velocity of 60°/sec, ROM, average proprioceptive errors at 15-45° and 30-60°, BBS scores, WOMAC subscale scores, VAS scores, and physical function tests significantly improved compared to the pre-treatment results (p<0.001). Statistically significant correlations were found between the pre- and post-treatment BBS score changes and pre- and post-treatment VAS (p=0.015), WOMAC-Pain (p=0.017), WOMAC-Physical Function (p=0.005) scores and Timed Up and Go Test (p=0.036) scores.

CONCLUSION

Inclusion of isokinetic quadriceps and hamstring strengthening exercises into the rehabilitation programs for the patients with knee osteoarthritis may improve the quality of life and contribute to the decreased risk of fall.

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

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

ACL substitution may improve kinematics of PCL-retaining total knee arthroplasty

PURPOSE

One of the key factors responsible for altered kinematics and joint stability following contemporary total knee arthroplasty (TKA) is resection of the anterior cruciate ligament (ACL). However, ACL retention can present several technical challenges, and in some cases may not be viable due to an absent or nonfunctional ACL. Therefore, the goal of this research was to investigate whether substitution of the ACL through an anterior post mechanism could improve kinematic deficits of contemporary posterior cruciate ligament (PCL) retaining implants.

METHODS

Kinematic analysis of different implant types was done using KneeSIM, a previously established dynamic simulation tool. Walking, stair-ascent, chair-sit, and deep knee bend were simulated for an ACL-substituting (PCL-retaining) design, a bi-cruciate-retaining and ACL-sacrificing (PCL-retaining) implant, as well as the native knee. The motion of the femoral condyles relative to the tibia was recorded for kinematic comparisons.

RESULTS

The ACL-substituting and ACL-retaining implants provided similar kinematic improvements over the ACL-sacrificing implant, by reducing posterior femoral shift in extension and preventing paradoxical anterior sliding. During all simulated activities, the ACL-sacrificing implant showed between 7 and 8 mm of posterior shift in extension in contrast to the ACL-retaining implant and the ACL-substituting design, which showed overall kinematic trends similar to the native knee.

CONCLUSION

The absence of ACL function has been linked to abnormal kinematics and joint stability in patients with contemporary TKA. ACL-substituting implants could be a valuable treatment option capable of overcoming the limitations of contemporary TKA, particularly when retaining the native ACL is not feasible or is challenging.

Rehabilitation Principles of the Anterior Cruciate Ligament Reconstructed Knee: Twelve Steps for Successful Progression and Return to Play

The rehabilitation process begins immediately after injury to the anterior cruciate ligament (ACL). The goal of preoperative rehabilitation is to prepare the patient for surgery. Current rehabilitation programs focus on strengthening exercises and proprioceptive and neuromuscular control drills to provide a neurologic stimulus. It is also important to address preexisting factors, especially for the female athlete, that may predispose to future injury, such as hip and hamstring weakness. Our goal in the rehabilitation program is to restore full, unrestricted function and to assist the patient to return to 100% of the preinjury level while achieving excellent long-term outcomes.

Knee joint kinematics after dynamic intraligamentary stabilization: cadaveric study on a novel anterior cruciate ligament repair technique

PURPOSE

Dynamic intraligamentary stabilization (DIS) has been introduced for the repair of acute anterior cruciate ligament (ACL) tears as an alternative to delayed reconstruction. The aim of the present study was to compare knee joint kinematics after DIS to those of the ACL-intact and ACL-deficient knee under simulated Lachman/KT-1000 and pivot-shift tests. We hypothesized that DIS provides knee joint kinematics equivalent to an intact ACL.

METHODS

With the use of a robotic knee simulator, knee kinematics were determined in simulated Lachman/KT-1000 and pivot-shift tests at 0°, 15°, 30°, 60°, and 90° of flexion in eight cadaveric knees under the following conditions: (1) intact ACL, (2) ACL deficiency, (3) DIS with a preload of 60 N, and (4) DIS with a preload of 80 N. Statistical analyses were performed using two-factor repeated-measures analysis of variance. The significance level was set at a p value of <0.05.

RESULTS

After DIS with a preload of either 60 N or 80 N, the anterior translation was significantly reduced in the simulated Lachman/KT-1000 and pivot-shift tests when compared to the ACL-deficient knee (p < 0.05). No significant differences were observed between the DIS reconstruction with a preload of 80 N and the intact ACL with regard to anterior laxity in either test. However, DIS with a preload of only 60 N was not able to restore knee joint kinematics to that of an intact knee in all degrees of flexion.

CONCLUSION

DIS with a preload of 80 N restores knee joint kinematics comparable to that of an ACL-intact knee and is therefore capable of providing knee joint stability during ACL healing. DIS therefore provides a new technique for primary ACL repair with superior biomechanical properties in comparison with other techniques that have been described previously, although further clinical studies are required to determine its usefulness in clinical settings.

Correlation among proprioception, muscle strength, and balance

[Purpose] To study the correlation among proprioception, muscle strength, and balance. [Subjects and Methods] A balance testing system (Biodex Balance System, BBS) and an isokinetic testing system (Biodex System 4, BS4) were used to test related indexes in 24 healthy young females. [Results] With the knee joint at 15 degree flexion, proprioception was significantly correlated with Limits of Stability-Time values, and was highly significantly correlated with Limits of Stability-Overall and Athlete Single Leg Medial/Lateral values. The sense of force was significantly correlated with Limits of Stability-Overall and Athlete Single Leg-Overall values. Quadriceps strength was significantly associated with Limits of Stability-Overall, Athlete Single Leg Medial/Lateral, and Athlete Double Leg-Overall values. The ratio of Quadriceps to Hamstring strength was significantly correlated with Athlete Single Leg Medial/Lateral, and Athlete Single Leg-Overall values. With the knee joint at 45°, proprioception was highly significantly correlated with dynamic balance, and was significantly correlated with double foot support under static balance; force sense had a high correlation with Limits of Stability-Overall, but no correlation with other indexes. Quadriceps strength had a significant correlation with dynamic and static balance; the ratio of Quadriceps/Hamstring had a highly significant correlation with Limits of Stability-Overall, Athlete Single Leg-Anterior/Posterior and Athlete Single Leg-Overall. [Conclusion] At different knee angles, the correlation differs among proprioception, force sense, quadriceps strength, the Quadriceps/Hamstring ratio, and balance.

Does the tibial remnant of the anterior cruciate ligament promote ligamentization?

BACKGROUND

The purpose of this study was to clarify the difference in ligamentization between the remnant-preserving (RP) and remnant-sacrificing (RS) techniques in anterior cruciate ligament (ACL) reconstruction using magnetic resonance imaging (MRI).

METHODS

A retrospective comparative study was carried out on 98 patients undergoing ACL reconstruction using either an RP (n=56) or RS (n=42) technique. MRI was performed at one of four time points postoperatively, and the signal intensity of the ACL graft was analyzed using the signal to noise quotient (SNQ) ratio and inter-bundle high signal intensity, along with an analysis of the survival rate of remnant tissue.

RESULTS

The mean SNQ ratio of grafted tendons in the RP group was significantly higher than that seen in the RS group in the proximal and middle regions two to four months after surgery (P<0.05) and was significantly lower than that seen in the RS group in all regions at 12 -18months (P<0.05). The inter-bundle high signal intensity was observed more frequently in the RP group (73.7%) at two to four months. Tibial remnants were observed on postoperative MRI regardless of when MRI was conducted.

CONCLUSION

The ACL graft of the RP group showed higher signal intensity in the early stage and lower signal intensity in the late stage compared to that of the RS group. The ligamentization of grafts in the RP group proceeded more quickly. Preserving the remnant in ACL reconstruction appears to have a positive effect on ligamentization.

Repeatability of position sense measurements in persons with osteoarthritis of the knee: a pilot study

Several reports have described a position sense deficit in persons with osteoarthritis of the knee. For purposes of future comparison, this study determined the agreement between serial measurements of knee position sense conducted over a 10-day period for eight persons of mean age 67.87 ± 7.36 years with stable knee-joint disease. The knee angles used to determine position sense were recorded in the seated position using a potentiometer. The outcome measure was the mean absolute error between five set angles and their matching angles. The intra-class correlation coefficients (ICCS) used to assess reliability of the mean absolute error measurements within and between sessions ranged from 0.57 to 0.52 with an average standard error of measurement of 1.18 degrees. It is concluded that while fairly reliable, clinicians should interpret changes in knee position sense of less than 2.31 degrees carefully in these patients before concluding that a true improvement or deterioration in their knee positioning accuracy has occurred.

Lower extremity muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects

BACKGROUND

Previous studies mainly focused on muscles at the operated knee after anterior cruciate ligament reconstruction, less on muscles around other joints of the operated and non-operated leg. The aim of this study was to investigate muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects.

METHODS

Lower extremity muscle activation onset times of both legs of 20 fully returned to sport anterior cruciate ligament reconstructed subjects and 20 non-injured control subjects were measured during the transition from double-leg stance to single-leg stance in eyes open and eyes closed conditions. Analysis of covariance (ANCOVA) was used to evaluate differences between groups and differences between legs within both groups, while controlling for peak center of pressure velocity.

FINDINGS

Significantly delayed muscle activation onset times were found in the anterior cruciate ligament reconstructed group compared to the control group for gluteus maximus, gluteus medius, vastus medialis obliquus, medial hamstrings, lateral hamstrings and gastrocnemius in both eyes open and eyes closed conditions (P<.05). Within the anterior cruciate ligament reconstructed group, no significant different muscle activation onset times were found between the operated and non-operated leg (P>.05).

INTERPRETATION

Despite completion of rehabilitation and full return to sport, the anterior cruciate ligament reconstructed group showed neuromuscular control deficits that were not limited to the operated knee joint. Clinicians should focus on relearning multi-segmental anticipatory neuromuscular control strategies after anterior cruciate ligament reconstruction.

Foot Pressure Pattern During Walking in Individuals with Anterior Cruciate Ligament Injury

BACKGROUND

We evaluated foot pressure distribution during walking in individuals with anterior cruciate ligament (ACL) injury.

METHODS

Our study included 24 ACL-deficient patients and 22 healthy young adults as controls. The former group was divided into the dominant-side ACL-deficient group (n = 17) and the nondominant-side ACL-deficient group (n = 7). The following parameters were calculated from the path of the center of pressure (COP) on a foot pressure distribution system: percentage of COP (%COP; the ratio of anteroposterior COP path length to foot length), percentage of COP locus area (%CLA; the ratio of the area encompassed by the COP path and a line between the start and end points of the COP path to foot area), and the value of maximum amplitude of COP (MACOP; the maximum perpendicular length from the COP path to a line between the start and end points of the COP).

RESULTS

In the nondominant-side ACL-deficient group, %COP (P = .026), %CLA (P = .001), and MACOP (P =.012) on the injured side were significantly lower than those in the nondominant leg side of the control group. No significant differences were found between the dominant-side ACL-deficient group and the control group.

CONCLUSIONS

Shortening of the COP trace in the nondominant-side ACL-deficient group may be associated with knee flexion during walking at heel contact. Because the parameters used herein can be obtained easily, repetitively, and quantitatively, they should be used in evaluating the gait of patients with ACL-deficient knees.

Five year results of the first ten ACL patients treated with dynamic intraligamentary stabilisation

Background

In recent years, the scientific discussion has focused on new strategies to enable a torn anterior cruciate ligament (ACL) to heal into mechanically stable scar tissue. Dynamic intraligamentary stabilization (DIS) with LigamysTM was first performed in a pilot study of 10 patients. The purpose of the current study was to evaluate the five year results of this group.

Methods

Inclusion criteria were an ACL rupture not older than 14 days, patient age <45 years, no previous surgery on the injured knee, and regular participation in sports requiring pivoting of the knee joint. Ten consecutive patients (eight males, two females) underwent surgery between August 2009 and February 2010. They were treated by DIS employing an internal stabilizer to keep the unstable knee in a posterior translation, combined with microfracturing and platelet-rich fibrin induction at the rupture site to promote self-healing. Postoperative clinical outcome [Tegner, Lysholm, International Knee Documentation Committee (IKDC), visual analogue scale patient satisfaction score] and assessment of knee laxity was performed at 3, 6, 12, 24 and 60 months.

Results

Median patient age at time of surgery was 23.3 years (range 19–41 years). The median time to surgery was 10 days (range 5–13 days). The rupture was located in the middle third of the ligament in seven patients and in the proximal third in three patients. Eight patients showed additional meniscal lesions, which were surgically treated in six patients. Eight of the ten patients reached the five-years follow-up. Median Lysholm score was 100 (range 90–100); the IKDC score was 98.9 (range 79.3–100); Tegner score was 5.5 (range 5–7); median Lachman difference to the other side was 2 mm (range 0–4 mm). Median patient satisfaction was 10 points (range 8–10 pts.). Four of the ten patients underwent metal removal (tibial implant component) after ACL healing and a consequently stable knee joint. Two patients suffered from a re-rupture at 5 months and 4.2 years after surgery and were treated with a bone-tendon-bone ACL graft.

Conclusions

Dynamic intraligamentary stabilization in ten active patients with a fresh ACL rupture showed a 5-years survival rate of 80 %. At the last follow-up all patients with a functionally healed ACL showed excellent outcomes and satisfaction with regards to the treatment result.

Effect of Time after Anterior Cruciate Ligament Tears on Proprioception and Postural Stability

This study was designed to compare proprioception and postural stability in patients with acute (time from injury ≤ 3 months) and chronic (time from injury > 3 months) ACL tears, and to evaluate the correlation between time interval after ACL injury and proprioception. Thigh muscle strength, postural stability, and joint position sense were compared in 48 patients with acute ACL tears and in 28 with chronic ACL tears. Maximal torque (60°/sec) of the quadriceps and hamstring was evaluated using an isokinetic testing device. Postural stability was determined from the anterior-posterior (APSI), medial-lateral (MLSI), and overall (OSI) stability indices using stabilometry. Joint position sense was also tested by reproduction of passive positioning (RPP). Muscle strengths and stability indices on both the involved and uninvolved sides were similar in the acute and chronic ACL tear groups. RPP on the involved side was significantly greater in the chronic than in the acute ACL tear group (7.8° vs. 5.6°, P = 0.041). Two of three stability indices (APSI, OSI) and RPP were significantly greater on the involved than the uninvolved side in the chronic ACL tear group.

Proprioceptive deficit in patients with complete tearing of the anterior cruciate ligament

Objective

To investigate the existence of proprioceptive deficits between the injured limb and the uninjured (i.e. contralateral normal) limb, in individuals who suffered complete tearing of the anterior cruciate ligament (ACL), using a strength reproduction test.

Methods

Sixteen patients with complete tearing of the ACL participated in the study. A voluntary maximum isometric strength test was performed, with reproduction of the muscle strength in the limb with complete tearing of the ACL and the healthy contralateral limb, with the knee flexed at 60°. The meta-intensity was used for the procedure of 20% of the voluntary maximum isometric strength. The proprioceptive performance was determined by means of absolute error, variable error and constant error values.

Results

Significant differences were found between the control group and ACL group for the variables of absolute error (p = 0.05) and constant error (p = 0.01). No difference was found in relation to variable error (p = 0.83).

Conclusion

Our data corroborate the hypothesis that there is a proprioceptive deficit in subjects with complete tearing of the ACL in an injured limb, in comparison with the uninjured limb, during evaluation of the sense of strength. This deficit can be explained in terms of partial or total loss of the mechanoreceptors of the ACL.

The Effects of Balance Training on Static and Dynamic Postural Stability Indices After Acute ACL Reconstruction

Background:

Proprioception and postural stability play an important role in knee movements. However, there are controversies about the overall recovery time of proprioception following knee surgery and onset of balance and neuromuscular training after ACL reconstruction. Therefore, it is necessary to evaluate the effect of balance training in early stage of knee rehabilitation after anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to evaluate the effect of balance exercises on postural stability indices in subjects with anterior cruciate ligament (ACL) reconstruction.

Methods:

The study was a controlled randomized trial study. Twenty four patients who had ACL reconstructed (balance training group) and twenty four healthy adults without any knee injury (control group) were recruited in the study. The balance exercises group performed balance exercises for 2 weeks. Before and after the interventions, overall, anteroposterior, and mediolateral stability indices were measured with a Biodex Balance System in bilateral and unilateral stance positions with the eyes open and closed. T-tests were used for statistical analysis (p<0.05).

Results:

Results showed that amount of static stability indices did not change after training and there were not significant differences in static stability indices before and after balance training (p>0.05). Although amount of dynamic stability indices decreased, there were not significant differences in dynamic stability indices before and after balance training (p>0.05). Amount of dynamic stability indices were decreased in balance training group, however, there were not significant differences between groups (p>0.05).

Conclusion:

These results support that balance exercise could partially improved dynamic stability indices in early stage of ACL reconstruction rehabilitation. The results of this study suggest that balance exercises should be part of the rehabilitation program following ACL reconstruction.