Knee joint position sense ability in elite athletes who have returned to international level play following ACL reconstruction: A cross-sectional study

Sensorimotor Dysfunction Following Anterior Cruciate Ligament Reconstruction- an Afferent Perspective: A Scoping Review

Background

Sensorimotor dysfunction is thought to occur following anterior cruciate ligament (ACL) injury which may have implications on future reinjury risk. Dysfunction has been demonstrated within the efferent component of the sensorimotor system. However, no reviews have examined the two main components of the afferent system: the visual and somatosensory systems.

Hypothesis/Purpose

This study aimed to report differences in function (central processing and local processing) within the (1) somatosensory and (2) visual systems between individuals following anterior cruciate ligament reconstruction (ACLR) and healthy controls (between-subject). The study also aimed to report differences in function within the two systems between the two limbs of an individual following ACLR (within-subject).

Study Design

Scoping review.

Methods

A search was conducted in PubMed, SPORTDiscus, CINAHL, Medline and Embase up until September 2021. Level I-IV studies assessing somatosensory and visual systems were included if they compared ACLR limbs to the uninjured contralateral limb (within-subject) or a healthy control limb (between-group). The function of somatosensory and visual systems was assessed across both central processing (processing of information in the central cortex) and local processing (all other assessments outside of central processing of information).

Results

Seventy studies were identified (52 somatosensory, 18 visual). Studies examining somatosensory central processing demonstrated significant differences; 66% of studies exhibited within-subject differences and 100% of the studies exhibited between-group differences. Studies examining local somatosensory processing had mixed findings; 40% of the 'joint position sense (JPS)' and 'threshold to detect motion (TTDM)' studies showed significant within-subject differences (JPS=0.8°-3.8° and TTDPM=0.2°-1.4°) and 42% demonstrated significant between-group differences (JPS=0.4°-5° and TTDPM=0.3°-2.8°). Eighty-three percent of visual central processing studies demonstrated significant dysfunction between-groups with no studies assessing within-subject differences. Fifty percent of the studies examining local visual processing demonstrated a significant between-group difference.

Conclusion

Significant differences in central processing exist within somatosensory and visual systems following ACLR. There is mixed evidence regarding local somatosensory and visual processing. Increased compensation by the visual system and local visual processing dysfunction may occur in conjunction with somatosensory dysfunction.

Functional leg performance 2 years after ACL surgery: a comparison between InternalBrace™-augmented repair versus reconstruction versus healthy controls

BACKGROUND

While clinical and patient-reported outcomes have been investigated in patients after InternalBrace™-augmented anterior cruciate ligament repair (ACL-IB), less is known regarding restoration of functional performance. We aimed to determine differences in functional performance within and between patients 2 years after ACL-IB, patients 2 years after ACL reconstruction (ACL-R), and healthy controls.

MATERIALS AND METHODS

A total of 29 ACL-IB, 27 ACL-R (hamstring autograft), and 29 controls performed single-leg hop (maximum forward distance hop, SLH; side hop > 40 cm in 30 s, SH), proprioception (knee joint position sense at 30° and 60° flexion), and dynamic postural balance (Y Balance) tests. Differences were calculated within groups (side-to-side difference) and between the involved leg of patients and the non-dominant leg of controls, and were evaluated to predefined statistical (P < 0.05), clinically relevant, and methodological (smallest detectable change) thresholds. The number of exceeded thresholds represented no (0), small (1), moderate (2), or strong (3) differences. In addition, the relative number of participants achieving leg symmetry (≥ 90%) and normal performance (≥ 90% of the average performance of the non-dominant leg of controls) were compared between groups (chi-squared tests, P < 0.05).

RESULTS

We observed no-to-moderate leg differences within ACL-IB (moderate difference in hops) and within ACL-R (moderate difference in knee proprioception), no leg differences between patient groups, no-to-small leg differences between ACL-IB and controls, and no leg differences between ACL-R and controls in functional performance. However, two patients in ACL-IB and ACL-R, respectively, passed the hop pretest only with their uninvolved leg, and fewer patients after ACL-IB and ACL-R than controls reached a leg symmetry and normal leg performance of controls in SLH (P < 0.001).

CONCLUSIONS

Functional performance seems to be comparable 2 years postoperatively between ACL-IB and ACL-R for a specific subgroup of patients (i.e., proximal ACL tears, moderate activity level). However, the presumed advantage of comparable functional outcome with preserved knee structures after augmented ACL repair compared with ACL-R, and the tendency of both patient groups toward leg asymmetry and compromised single-leg hop performance in the involved legs, warrants further investigation. Level of Evidence Level III, case-control study. Trial registration clinicaltrials.gov, NCT04429165 (12/09/2020). Prospectively registered, https://clinicaltrials.gov/ct2/show/NCT04429165 .

The Need To Change Return to Play Testing in Athletes Following ACL Injury: A Theoretical Model

The incidence of knee injuries in sport, particularly involving the ACL, appears to be increasing yearly, especially in younger age athletes. Even more concerning is the frequency of ACL reinjury also appears to be increasing year after year. Improving the objective criteria and testing methods used to determine return to play (RTP) readiness following ACL surgery is one aspect of the rehabilitation process that can significantly help in reducing reinjury rates. Currently, the majority of clinicians are still using post operative time frames as their number one criterion for clearance to RTP. This flawed method demonstrates an inadequate reflection of the true unpredictable, dynamic environment athletes are returning to participate in. In our clinical experience, objective testing to allow for clearance to sport participation following an ACL injury should incorporate neurocognitive and reactive testing due to the nature of the injury typically occurs because of failed control of unanticipated reactive movements. The purpose of this manuscript is to share a neurocognitive testing sequence we currently employ consisting of 8 tests in 3 categories: Blazepod tests, reactive shuttle run tests, and reactive hop tests. The use of a more dynamic reactive testing battery may decrease the reinjury rates when an athlete is cleared for participation by measuring readiness in chaotic circumstances that are more truly reflective of the sporting environment the athlete is working to return to and in the process give them a greater sense of confidence.

Effect of an Anterior Cruciate Ligament Rupture on Knee Proprioception Within 2 Years After Conservative and Operative Treatment: A Systematic Review with Meta-Analysis

BACKGROUND

The anterior cruciate ligament (ACL) plays a major role in knee proprioception and is thus responsible for maintaining knee joint stability and functionality. The available evidence suggests that ACL reconstruction diminishes somatosensory feedback and proprioceptive functioning, which are vital for adequate joint positioning and movement control.

OBJECTIVE

The aim of this systematic review and meta-analysis was to investigate the effect of an ACL rupture on knee proprioception after arthroscopic ACL repair surgery or conservative treatment.

METHODS

A systematic review with meta-analysis was conducted according to the Preferred Reporting Guidelines for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The literature search was performed in the following databases from inception to 10th October 2020: PubMed, Web of Science, SPORTDiscus, Cochrane Library and Scopus. Randomized and non-randomized studies that evaluated proprioception using the joint position sense (JPS) and threshold to detection of passive motion (TTDPM) techniques at 15°-30° knee flexion with an external healthy control group in a time period between 6 and 24 months post injury or operation were included in the analysis.

RESULTS

In total, 4857 studies were identified, from which 11 were included in the final quantitative analysis. The results demonstrated that proprioception after arthroscopic ACL repair surgery was significantly lower than in the healthy control group (JPS: standardized mean difference [SMD] 0.57, 95% confidence interval [CI] 0.27-0.87, p < 0.01, n = 6 studies; TTDPM: SMD 0.77, 95% CI 0.20-1.34, p < 0.01, n = 4 studies). There were no significant differences in proprioception between the conservative treatment group and the healthy control group (JPS: SMD 0.57, 95% CI - 0.69 to 1.84, p = 0.37, n = 4 studies; TTDPM: SMD 0.82, 95% CI - 0.02 to 1.65, p = 0.05, n = 2 studies), although measures for TTDPM were close to statistical significance.

CONCLUSION

The findings of the present systematic review and meta-analysis revealed that knee proprioception is persistently compromised 6-24 months following surgical treatment of ACL tears compared with healthy controls. The reduced kinesthetic awareness after ACL surgery is of high relevance for optimizing individual treatment plans in these patients. As the current literature is still scarce about the exact underlying mechanisms, further research is needed.

TRIAL REGISTRATION

The present systematic review was registered in PROSPERO (CRD42021198617).

Joint position sense, motor imagery and tactile acuity in lateral elbow tendinopathy: A cross-sectional study

BACKGROUND

Impairments of sensorimotor function are evident in individuals with lateral elbow tendinopathy (LET), although understanding of the mechanisms for this is lacking.

OBJECTIVES

To determine if motor imagery, tactile acuity and wrist joint position sense (JPS) are impaired in participants with unilateral LET compared to controls, whether deficits are localised to the affected side, and whether deficits relate to severity of pain.

DESIGN

Cross-sectional study with control group.

METHODS

14 participants with unilateral LET of 6 weeks or longer and 14 matched control participants were assessed bilaterally for motor imagery (left/right hand judgement task), tactile acuity (two-point discrimination test) and wrist JPS (reposition test for flexion and extension). Pain levels were measured using a numeric rating scale.

RESULTS

Significant differences in JPS were observed for wrist extension only, such that participants with LET adopted less extended postures with their affected side when compared to their unaffected side (MD = 2.97°; p = 0.01) and to the matched-affected side of controls (MD = 4.89°; p < 0.01). No differences in tactile acuity or motor imagery were observed.

CONCLUSION

Altered wrist extension JPS, but not motor imagery or tactile acuity, was found in the affected side of patients with unilateral LET when compared to non-injured side and asymptomatic controls.

Reliability of joint position sense measured in the knee using the level function of the iPhone "Measure" application

An impaired joint position sense (JPS) causes activity limitations, postural imbalance, and falls. This study compares the reliability of knee JPS measurements between the iPhone's "Measure" application and VICON motion capture system. Eleven healthy participants were recruited for the study. To conduct the study measures, the blindfolded participant, with an iPhone fixed to the lower non-dominant leg, was seated with their lower limbs in a relaxed position. The examiner held the participant's leg at the target angle (30°/60° from initial position) for 5 s before releasing it. The participant was then instructed to move the leg to the same target angle and hold it for 5 s (replicated angle). Absolute angular error (AAE), i.e., the difference between the target and replicated angles, was measured. Intraclass and Pearson correlation coefficients established statistically significant relationships. The study comprised 6 males and 5 females of mean age 27.6±5.6 years, mean height 1.67±0.10 m, and mean body weight 60.7±10.3 kg. Strong correlations existed between iPhone and VICON 30° (ICC = 0.969, r = 0.960, P < 0.001) and 60° AAEs (ICC 0.969, r = 0.960, P < 0.001). Bland-Altman plots showed a mean difference of 0.43° and 0.20° between the AAE measurements at 30° and 60°, respectively. The iPhone's "Measure" application is a simple and reliable method for measuring JPS in clinical practice and sports/fitness settings.

Properties of Knee Joint Position Sense Tests for Anterior Cruciate Ligament Injury: A Systematic Review and Meta-analysis

Background:

Knee proprioception is believed to be deficient after anterior cruciate ligament (ACL) injury. Tests of joint position sense (JPS) are commonly used to assess knee proprioception, but their psychometric properties (PMPs) are largely unknown.

Purpose:

To evaluate the PMPs (reliability, validity, and responsiveness) of existing knee JPS tests targeting individuals with ACL injury.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

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

Results:

Included were 80 studies covering 119 versions of knee JPS tests. Meta-analyses indicated sufficient quality for known-groups and discriminative validity (ACL-injured knees vs knees of asymptomatic controls and contralateral noninjured knees, respectively), owing to significantly greater absolute errors for ACL-injured knees based on a strong level of evidence. A meta-analysis showed insufficient quality for responsiveness, which was attributed to a lack of significant change over time after diverse interventions with a moderate level of evidence. Statistical heterogeneity (I² > 40%) was evident in the majority of meta-analyses. All remaining PMPs (reliability, measurement error, criterion validity, convergent validity, and other PMPs related to responsiveness) were assessed qualitatively, and they failed to achieve a sufficient quality rating. This was a result of either the study outcomes not agreeing with the statistical cutoff values/hypotheses or the level of evidence being rated as conflicting/unknown or based on only a single study.

Conclusion:

Knee JPS tests appear to have sufficient validity in differentiating ACL-injured knees from asymptomatic knees. Further evidence of high methodologic quality is required to ascertain the reliability, responsiveness, and other types of validity assessed here. We recommend investigations that compare the modifiable methodologic components of knee JPS tests on their PMPs to develop standardized evidence-based tests.

Alterations in sensorimotor function after ACL reconstruction during active joint position sense testing. A systematic review

BACKGROUND

The anterior cruciate ligament (ACL) rupture can lead to impaired knee function. Reconstruction decreases the mechanical instability but might not have an impact on sensorimotor alterations.

OBJECTIVE

Evaluation of the sensorimotor function measured with the active joint position sense (JPS) test in anterior cruciate ligament (ACL) reconstructed patients compared to the contralateral side and a healthy control group.

METHODS

The databases MEDLINE, CINAHL, EMBASE, PEDro, Cochrane Library and SPORTDiscus were systematically searched from origin until April 2020. Studies published in English, German, French, Spanish or Italian language were included. Evaluation of the sensorimotor performance was restricted to the active joint position sense test in ACL reconstructed participants or healthy controls. The Preferred Items for Systematic Reviews and Meta-Analyses guidelines were followed. Study quality was evaluated using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Data was descriptively synthesized.

RESULTS

Ten studies were included after application of the selective criteria. Higher angular deviation, reaching significant difference (p < 0.001) in one study, was shown up to three months after surgery in the affected limb. Six months post-operative significantly less error (p < 0.01) was found in the reconstructed leg compared to the contralateral side and healthy controls. One or more years after ACL reconstruction significant differences were inconsistent along the studies.

CONCLUSIONS

Altered sensorimotor function was present after ACL reconstruction. Due to inconsistencies and small magnitudes, clinical relevance might be questionable. JPS testing can be performed in acute injured persons and prospective studies could enhance knowledge of sensorimotor function throughout the rehabilitative processes.

Development of supine and standing knee joint position sense tests

OBJECTIVES

We aimed to assess the test-retest reliability of a supine and standing knee joint position sense (JPS) test, respectively, and whether they discriminate knees with anterior cruciate ligament (ACL) injury from asymptomatic knees.

DESIGN

Repeated measures and cross-sectional.

SETTING

Research laboratory.

PARTICIPANTS

For test-retest reliability, 24 persons with asymptomatic knees. For discriminative analysis: 1) ACLR - 18 persons on average 23 months after unilateral ACL reconstruction, 2) CTRL - 23 less-active persons, and 3) ATHL - 21 activity level-matched athletes.

MAIN OUTCOME MEASURES

Absolute error (AE) and variable error (VE).

RESULTS

Test-retest reliability was generally highest for AE of the standing test (ICC 0.64-0.91). Errors were less for the standing compared to the supine test across groups. CTRL had greater knee JPS AE (P = 0.005) and VE (P = 0.040) than ACLR. ACLR knees showed greater VE compared to the contralateral non-injured knees for both tests (P = 0.032), albeit with a small effect size (η_p² = 0.244).

CONCLUSIONS

Our standing test was more reliable and elicited lesser errors than our supine test. Less-active controls, rather than ACLR, produced significantly greater errors. Activity level may be a more predominant factor than ACLR for knee JPS ∼2 years post-reconstruction.

The effects of partial meniscectomy and meniscal repair on the knee proprioception and function

PURPOSE

Aim of our study was to compare the effects of partial meniscectomy and meniscus repair on knee proprioception and function.

METHODS

The study included 46 patients with clinical and radiological diagnosis of meniscal tear and accompanying anterior cruciate ligament (ACL) rupture. The patients were evaluated under two groups: group 1: partial meniscectomy and ACL reconstruction, and group 2: meniscal repair and ACL reconstruction. Proprioceptive and functional evaluation of all patients was performed prior to surgery and on postoperative 12th month.

RESULTS

Group 1 consists of 18 male and 1 female patients with an average age of 28.78 ± 3.50. Group 2 consists of 23 male and 4 female patients with an average age of 27.14 ± 3.65. Preoperative evaluation revealed significant differences in knee joint position sense values on wide range of knee motion (15°, 30°, 45°, 60°, and 75°) in both groups. The statistically significant difference was observed in only the range of knee motion of 60° in patients underwent meniscal repair (group 2), whereas in the range of knee motion of 45°, 60°, and 75° in patients underwent partial meniscectomy (group 1) at 12th-month control. According to Lysholm knee scoring system, significantly better results were achieved with meniscal repair compared to the partial meniscectomy at 12th-month control.

CONCLUSION

In case of ACL rupture accompanied by meniscal tear, the meniscal repair should be sutured, if possible, in order to obtain better results in terms of knee function and proprioception.

Neuromuscular training improves knee proprioception in athletes with a history of anterior cruciate ligament reconstruction: A randomized controlled trial

BACKGROUND

Athletes exhibit deficits in knee proprioception following anterior cruciate ligament reconstruction. Neuromuscular training programs improve knee proprioception in uninjured athletes; however, the effects on knee proprioception in athletes who have undergone anterior cruciate ligament reconstruction is not well understood. The purpose of this study was to examine the effects of a neuromuscular training program on knee proprioception in athletes who have returned to sport following anterior cruciate ligament reconstruction.

METHODS

Twenty-four male athletes, who had undergone anterior cruciate ligament reconstruction within the previous 6-12 months and returned to sport, participated in this randomized controlled trial. Athletes were randomly allocated to an experimental group (n = 12) that took part in an 8-week neuromuscular training program or a control group (n = 12) that simply continued their typical training routine. Knee position sense was assessed at baseline and after the 8-week period (post-testing). One-way analysis of covariance, with baseline performance included as a covariate, was used to compare knee position sense errors for the reconstructed limbs of the experimental and control groups at the post-testing time point.

FINDINGS

Knee position sense errors decreased by 51.7% for the experimental group and only 4.4% for the control group over the 8-week period. As a result, the experimental group demonstrated lower knee position sense errors, compared to the control group, at the post-testing time point (P < .001).

INTERPRETATION

Athletes with a history of anterior cruciate ligament reconstruction may benefit from participation in a neuromuscular training program, even after completing post-operative rehabilitation.

Effects of two exercise programmes on joint position sense, dynamic balance and countermovement jump in male amateur football players. A randomised controlled trial

Introduction: The injury prevention and warm-up exercises programmes improve physical performance and injury ratio, but it is poorly investigated in amateur football. Objectives: To assess the effects of two warm-up multi-station programmes (IAI-Programme and FIFA11+) through JPS, LSDT and CMJ. Study design: Randomised controlled trial. Methods: 36 football players were randomised into 2 groups: IAI-Programme (n = 18) and FIFA11+ (n = 18) and performed the intervention protocol for 6 weeks. JPS, LSDT and CMJ were measured at baseline, after 6, 10 and 18 weeks (from baseline). The inter-group and intra-group differences were assessed by repeated-measures analysis of variance test (ANOVA). Results: Significant differences between groups were found after 18 weeks in the absolute angular error (-2.18[-4.33,-0.047], d = 0.69, p < 0.05) of the JPS and in the CMJ (p = 0.001, ŋ²p=,0.298) in favour of IAI-Programme when compared to FIFA11 +. No significant differences between groups were found in the LSDT. There were also intra-group differences observed in the LSDT in both groups. Conclusions: IAI-Programme can provide sensitive benefits with respect to the proprioceptive ability of knee flexion and CMJ than FIFA11 +. Both IAI-Programme and FIFA11+ present improvements in the dynamic postural control measured by the LSDT.

The Effect of Proprioceptive Neuromuscular Facilitation on Joint Position Sense: A Systematic Review

Context: Accurate joint position sense (JPS) is necessary for effective motor learning and high performance in activities that require fine motor control. Proprioceptive neuromuscular facilitation (PNF) can be a promising intervention. Objective: To examine existing peer-reviewed original studies that have investigated the effect of PNF techniques on the JPS in terms of the methodological quality, PNF techniques, outcomes, and participant characteristics. Evidence Acquisition: A systematic literature search was performed using PubMed, EMBASE, MEDLINE, CINAHL, SocINDEX, Scopus, and Cochrane Library from inception to January 2018. The following inclusion criteria were used: (1) assessment of the JPS; (2) peer-reviewed original studies with a randomized controlled trial or quasi-randomized controlled trial design; (3) participants with musculoskeletal disorders or healthy individuals (ie, neither animal studies nor those involving neurological problems); and (4) no cointervention with PNF, except for warm-up procedures. The methodological quality was assessed using PEDro scale and 5 additional criteria. Effect size (η2) was calculated where a positive value indicated an increased JPS after PNF as compared with other approaches including the wait-and-see method. Evidence Synthesis: Nine studies were examined for their methodological quality, and only one study scored >6 on the PEDro scale. Positive and large effect size (η2 > .14) was detected in 2 studies where JPS of the knee with contract-relax and replication techniques was assessed in healthy individuals. However, the methodological quality of these studies was poor (PEDro scores of 3 and ≤5 in the total quality score out of 16, respectively). Conclusions: The current study did not find multiple studies with high methodological quality and similar PNF techniques, outcomes, and characteristics of participants. More high-quality studies are required to achieve a comprehensive understanding of the effect of PNF on the JPS.

Quadriceps tendon autograft ACL reconstructed subjects overshoot target knee extension angle during active proprioception testing

PURPOSE

To compare the active joint position sense (JPS), muscle strength, and knee functions in individuals who had anterior cruciate ligament (ACL) reconstruction with quadriceps tendon autograft, hamstring tendon autograft, tibialis anterior allograft and healthy individuals. It was hypothesized that when compared to an age and gender-matched healthy control group, subjects who were post-ACL reconstruction would display impaired active joint position sense, knee extensor and flexor strength symmetry and knee function at 1 year post-surgery. A secondary hypothesis was that differences would exist between the quadriceps tendon autograft, hamstring tendon autograft and tibialis anterior allograft groups.

METHODS

Sixty-seven patients with ACL reconstruction and 20 healthy individuals were included. Active JPS reproduction was measured at 15°, 45° and 75° of knee flexion. International Knee Documentation Committee (IKDC) subjective score and one-leg hop test were used to assess the functional status of the patients.

RESULTS

The JPS detection was different at the 15° target angle between groups (F_3.86 = 24.56, p < 0.001). A significantly higher proportion of quadriceps tendon autograft group patients failed to identify the 15° active JPS assessment position compared to the other groups (p < 0.0001). The quadriceps index was lower in patients compared to healthy individuals (p < 0.001), while the hamstring index was similar (n.s.). The knee functional outcomes were similar between ACL reconstructed groups and healthy controls (n.s.).

CONCLUSION

Knee proprioception deficits and impaired muscle strength were evident among patients at a mean 13.5 months post-ACL reconstruction compared with healthy controls. Patients who underwent ACL reconstruction using a quadriceps tendon autograft may be more likely to actively over-estimate knee position near terminal extension. Physiotherapists may need to focus greater attention on terminal knee extension proprioceptive awareness among this patient group.

LEVEL OF EVIDENCE

III.

Can texture change joint position sense at the knee joint in those with poor joint position accuracy?

Purpose: Skin contributes to joint position sense (JPS) at multiple joints. Altered cutaneous input at the foot can modulate gait and balance and kinesiology tape can enhance proprioception at the knee, but its effect may be dependent on existing capacity. The effect of texture at the knee, particularly in those with poor proprioception, is unknown. The aim of this study was to determine the effect of textured panels on JPS about the knee. Materials and methods: Eighteen healthy females were seated in an adjustable chair. Their left leg (target limb) moved passively from 65° to a target of flexion (115° or 90°) or extension (40°). Their right leg (matching limb) was passively moved towards this target angle and participants indicated when their limbs felt aligned. We tested three textured panels over the knee of the matching limb and two control conditions. The target limb maintained a control panel. Directional error, absolute error and variable error in matching between limbs were calculated. Results: On average textured panels over the knee increased JPS error compared to control pants for participants with poor JPS. These participants undershot the target at 90° of flexion significantly more with textured panels (-11° ± 3°) versus control (-7° ± 3°, p = 0.04). Conclusions: For participants with poor JPS accuracy, increased JPS error at 90° with a textured panel suggests these individuals utilised altered cutaneous information to adjust joint position. We propose increased error results from enhanced skin input at the knee leading to the perception of increased flexion.

Knee sensorimotor control following anterior cruciate ligament reconstruction: A comparison between reconstruction techniques

The sensorimotor system helps to maintain functional joint stability during movement. After anterior cruciate ligament (ACL) injury and reconstruction, several sensorimotor deficits may arise, including altered proprioception and changes in neuromuscular control. It is still unknown whether the type of autograft used in the reconstruction may influence knee sensorimotor impairments. The aim of this study was to comparatively assess the effects of the hamstring tendon (HT) and bone-patellar tendon-bone (BPTB) ACL reconstruction techniques on knee sensorimotor control 6–12 months post-operation. A total of 83 male subjects participated in this study: 27 healthy participants, 30 BPTB-operated patients and 26 HT-operated patients. Active joint position sense in 3 ranges of motion (90–60°, 60–30°, and 30–0° of knee flexion), isometric steadiness, and onset of muscle activation were used to compare sensorimotor system function between groups. Both operated groups had a small (< 5°) but significant joint position sense error in the 30–0° range when compared to the healthy group. No significant differences were found between the operated and the control groups for isometric steadiness or onset of muscle activation. The results of this study suggest that operated patients present knee proprioceptive deficits independently of surgical technique. Nevertheless, the clinical implications of this impairment are still unknown. It seems that selected surgical approach for ACL reconstruction do not affect functioning of the sensorimotor system to a large degree.

Is poor proprioception associated with worse movement quality of the knee in individuals with anterior cruciate ligament deficiency or reconstruction?

[Purpose] To investigate the association between proprioception and a knee medial to foot position during weight-bearing activities in patients with anterior cruciate ligament reconstruction and anterior cruciate ligament deficiency. [Participants and Methods] Thirty-eight patients with anterior cruciate ligament reconstruction and 13 patients with anterior cruciate ligament deficiency aged 18–40 years were included. Proprioception was assessed by knee kinesthesia measured by the threshold to detection of passive motion. Movement quality was assessed by visual observation of the position of the knee in relation to the foot during the mini squat, the single-leg hop for distance, and the cross-over hop for distance. [Results] In patients with anterior cruciate ligament deficiency, worse kinesthesia was significantly associated with a knee medial to foot position during the single-leg hop for distance. No statistically significant associations were observed between kinesthesia and a knee medial to foot position during the three tasks in patients with anterior cruciate ligament reconstruction. [Conclusion] Poor proprioception may be associated with worse movement quality of the knee in patients with anterior cruciate ligament deficiency, but not in patients with anterior cruciate ligament reconstruction. Differences in sensorimotor function between patients with reconstructed and non-reconstructed anterior cruciate ligament should be considered in training and rehabilitation regimens aiming to enhance performance and prevent further injuries in these patients.

Six weeks of multistation program on the knee proprioception and performance of futsal players

BACKGROUND

Proprioception and vertical jump are important parameters in the performance and prevention of injuries in futsal. However, very few studies have analyzed the role of multistation exercises to improve these variables. The purpose of this study was to assess the effects of a six-week multistation exercise program on knee joint position sense (JPS) and countermovement jump (CMJ) of futsal players.

METHODS

Thirty-four male futsal players randomly classified into experimental (N.=17) or control group (N.=17). The experimental group included a multistation exercise protocol to their training routines (2 times/week - 6 weeks); the control group continued their training routines. All the players completed similar training routines outside of the multistation exercises. Before (baseline), just after the intervention (Post6Wk) and four weeks later (Post10Wk), CMJ and knee JPS (absolute, relative and variable angular error: AAE, RAE and VAE, respectively) were evaluated.

RESULTS

ANOVA showed that the experimental group significantly decreased VAE at Post10Wk compared to baseline, suggestive of greater proprioceptive precision, while the control group significantly increased AAE, RAE and VAE at Post10Wk compared to baseline. The experimental group exhibited lower and thus, better AAE and VAE than the control group at Post10Wk, although no significant differences were found at Post6Wk. No significant differences was found in the CMJ.

CONCLUSIONS

A six weeks of multistation program may help improve proprioceptive precision of futsal players, even one month after finishing the 6-wk multistation training program. However, this is not long enough to improve proprioceptive acuity and maximum vertical jump. Therefore, the meaningful of these results in term of performance are unclear.

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

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