Proprioception and performance after anterior cruciate ligament rupture

Investigation of the correlation between knee joint position sense and physical functional performance in individuals with transtibial amputation

INTRODUCTION

In individuals with transtibial amputation, the distal part of the lower extremity is lost. Therefore, the knee joint is of greater importance to be able to provide physical performance. The aim of this study was to evaluate the correlation between knee joint position sense and physical functional performance in individuals with transtibial amputation.

METHODS

The study included 21 subjects with transtibial amputation. A digital inclinometer was used to evaluate the joint position sense of the amputated side knee joint. The timed up and go test, the 4-square step test, and 10-m walk test were used to evaluate physical functional performance. Linear regression analysis was used to investigate the associations between independent variables and functional performance tests.

RESULTS

The mean age of the participants was 52.52 ± 15.68 years. The mean of the error in knee joint position sense was 5.33 degree (standard deviation = 3.08 degree). The error in knee joint position sense of the amputated limb predicted 45% of the variance in the 4-square step test and 22% of the variance in the 10-m walk test ( P < 0.05).

CONCLUSIONS

The knee joint position sense on the amputated side was found to be associated with physical functional performance in individuals with transtibial amputation. Residual limb knee joint position sense should be considered when prescribing prostheses and planning rehabilitation programs.

Correlations of strength, proprioception, and tactile sensation to return-to-sports readiness among patients with anterior cruciate ligament reconstruction

Objectives: Anterior cruciate ligament reconstruction (ACLR) is the most common surgery for anterior cruciate ligament (ACL) injuries, and the relationships between patients' return to sports (RTS) readiness and different physical functions are inconclusive among patients with ACLR. This study aimed to investigate the correlations of strength, proprioception, and tactile sensation to the RTS readiness among patients with ACLR. Methods: Forty-two participants who received ACLR for at least 6 months were enrolled in this study. Their strength, proprioception, and tactile sensation were tested, and their RTS readiness was measured with the Knee Santy Athletic Return to Sports (K-STARTS) test, which consists of a psychological scale [Anterior Cruciate Ligament Return to Sports after Injury scale (ACL-RSI)] and seven functional tests. Partial correlations were used to determine their correlations while controlling for covariates (age, height, weight, and postoperative duration), and factor analysis and multivariable linear regressions were used to determine the degrees of correlation. Results: Knee extension strength was moderately correlated with K-STARTS total, ACL-RSI, and functional scores. Knee flexion strength, knee flexion and extension proprioception, and tactile sensation at the fifth metatarsal were moderately correlated with K-STARTS total and functional scores. Strength has higher levels of correlation with functional scores than proprioception. Conclusion: Rehabilitation to promote muscle strength, proprioception and tactile sensation should be performed among patients with ACLR, muscle strength has the highest priority, followed by proprioception, with tactile sensation making the least contribution.

Foot tapping and unilateral vertical jump performance in athletes after knee surgery: an explorative cross-sectional study

Background

Guiding athletes through the rehabilitation process and judging the time at which return to sports can be enabled after anterior cruciate ligament (ACL) injuries are still challenging processes. The purpose of this explorative cross-sectional study was to retrospectively compare unilateral vertical jump as well as vertical foot tapping outcomes in athletes returned to sports after ACL reconstruction (ACLR) with uninjured athletes.

Methods

Seven-teen ACLR athletes (male/female: 12/5) were examined 11 (6–23) months after their ACL injury and after return to sport clearance together with 67 uninjured athletes (male/female: 51/16). Seventeen age and stature matched controls were selected from the sample of uninjured athletes. Participants unilaterally performed acyclic (squat jump, SJ; drop jump, DJ) and cyclic (foot tapping, FT) tests. SJ peak power, DJ take-off efficiency (TOE) and FT coefficients (FTC) were compared between ACLR and matched as well as unmatched control groups. Limb symmetry index (LSI) as well as performance score were calculated.

Results

Analyses of the SJ peak power revealed moderate effects of group (right: P < 0.09, η_p² = 0.06; left: P < 0.05, η_p² = 0.08). The TOE was largely affected by group (right: P < 0.01, η_p² = 0.12; left: P < 0.01, η_p² = 0.13). No effect of group was found on the FTC (P > 0.8, η_p² < 0.01). The SJ peak power LSI (r = 0.46, P < 0.07) and TOE LSI (r = 0.38, P = 0.13) were positively associated with the performance score of the ACLR group.

Conclusion

Although already returned to sports, the ACLR group underperformed the matched and unmatched control groups significantly. Unilaterally performed vertical jumps may provide additional information on athletes’ rehabilitation progress and help to manage the rehabilitation process and decisions on potential readiness after ACLR. More attention should be paid to the direction of the LSI results.

Anterior Cruciate Ligament Reconstruction Increases the Risk of Hamstring Strain Injury Across Football Codes in Australia

OBJECTIVE

The aim of this study was to determine the impacts of anterior cruciate ligament reconstruction (ACLR) and recent (< 12 months) hamstring strain injury (HSI) on (1) future HSI risk, and (2) eccentric knee flexor strength and between-limb imbalance during the Nordic hamstring exercise. A secondary goal was to examine whether eccentric knee flexor strength was a risk factor for future HSI in athletes with prior ACLR and/or HSI.

METHODS

In this prospective cohort study, 531 male athletes had preseason eccentric knee flexor strength tests. Injury history was also collected. The main outcome was HSI occurrence in the subsequent competitive season.

RESULTS

Overall, 74 athletes suffered at least one prospective HSI. Compared with control athletes, those with a lifetime history of ACLR and no recent HSI had 2.2 (95% confidence interval [CI] 1.1-4.4; p = 0.029) times greater odds of subsequent HSI while those with at least one HSI in the previous 12 months and no history of ACLR had 3.1 (95% CI 1.8-5.4; p < 0.001) times greater odds for subsequent HSI. Only athletes with a combined history of ACLR and recent HSI had weaker injured limbs (p = 0.001) and larger between-limb imbalances (p < 0.001) than uninjured players. An exploratory decision tree analysis suggested eccentric strength may protect against HSI after ACLR.

CONCLUSION

ACLR and recent HSI were similarly predictive of future HSI. Lower levels of eccentric knee flexor strength and larger between-limb imbalances were found in athletes with combined histories of ACLR and recent HSI. These findings may have implications for injury rehabilitation.

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.

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.

Influence of posteromedial corner injuries on clinical outcome and second-look arthroscopic findings after allograft transtibial anterior cruciate ligament reconstruction

BACKGROUND

The purpose of this study was to evaluate the influence of posterior medial corner (PMC) injuries on clinical outcome and second-look arthroscopic findings after anterior cruciate ligament (ACL) reconstruction.

METHODS

Seventy-eight consecutive patients underwent a second-look arthroscopic surgery after ACL reconstruction and magnetic resonance imaging (MRI) examination of the PMC. The patients were divided into a PMC intact group (n = 42) and a PMC injured group (n = 36). The stability and clinical outcomes were evaluated using the Lachman test, pivot-shift test, a KT-2000 arthrometer, and the Lysholm knee scoring scale. Graft tension and synovial coverage were evaluated in second-look arthroscopy.

RESULTS

The clinical function showed no significant differences regarding PMC injury. Although the graft tendon tension revealed no significant differences (p = 0.141), the second-look arthroscopic findings indicated that the PMC intact group showed better synovial coverage compared to the PMC injured group (p = 0.012).

CONCLUSION

Patients who injured the PMC had poor synovial coverage as assessed by second-look arthroscopic findings after transtibial ACL reconstruction, even though clinical outcomes and stability showed no significant differences.

Recalibrating the risk of hamstring strain injury (HSI): A 2020 systematic review and meta-analysis of risk factors for index and recurrent hamstring strain injury in sport

OBJECTIVE

To systematically review risk factors for hamstring strain injury (HSI).

DESIGN

Systematic review update.

DATA SOURCES

Database searches: (1) inception to 2011 (original), and (2) 2011 to December 2018 (update). Citation tracking, manual reference and ahead of press searches.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies presenting prospective data evaluating factors associated with the risk of index and/or recurrent HSI.

METHOD

Search result screening and risk of bias assessment. A best evidence synthesis for each factor and meta-analysis, where possible, to determine the association with risk of HSI.

RESULTS

The 78 studies captured 8,319 total HSIs, including 967 recurrences, in 71,324 athletes. Older age (standardised mean difference=1.6, p=0.002), any history of HSI (risk ratio (RR)=2.7, p<0.001), a recent HSI (RR=4.8, p<0.001), previous anterior cruciate ligament (ACL) injury (RR=1.7, p=0.002) and previous calf strain injury (RR=1.5, p<0.001) were significant risk factors for HSI. From the best evidence synthesis, factors relating to sports performance and match play, running and hamstring strength were most consistently associated with HSI risk. The risk of recurrent HSI is best evaluated using clinical data and not the MRI characteristics of the index injury.

SUMMARY/CONCLUSION

Older age and a history of HSI are the strongest risk factors for HSI. Future research may be directed towards exploring the interaction of risk factors and how these relationships fluctuate over time given the occurrence of index and recurrent HSI in sport is multifactorial.

Proprioception in Patients With Anterior Cruciate Ligament Tears: A Meta-analysis Comparing Injured and Uninjured Limbs

BACKGROUND

Because of a reduction in the number of mechanoreceptors or alterations of their characteristics, anterior cruciate ligament (ACL) tears lead not only to mechanical instability but also to impaired proprioception. Purpose/Hypothesis: This study analyzed whether ACL tears cause a greater decrease in proprioception in injured than in uninjured knees. The hypothesis was that knee proprioception after ACL tears would decrease more in injured than in contralateral uninjured knees, regardless of the method used to measure knee proprioception.

STUDY DESIGN

Meta-analysis.

METHODS

We identified studies comparing proprioception in ACL-injured and contralateral intact knees using threshold for detection of passive motion (TTDPM) or joint position sense (JPS) tests. JPS was assessed by measuring the reproduction of passive positioning (RPP) or active repositioning (RAP) of the knee.

RESULTS

Sixteen studies were included in this meta-analysis. The pooled results of subgroup analyses of TTDPM for both 20° and 40° of knee flexion showed that mean angle of error was 0.23° (95% CI, 0.08°-0.37°) greater in ACL-injured than in contralateral intact knees ( P = .002). Pooled data RAP and RPP subgroup analyses also showed that the mean angle of error was 0.94° higher in ACL-injured than in contralateral intact knees. The mean difference in angle of error between ACL-injured and contralateral intact knees was 0.71° greater (95% CI, 0.68°-0.74°; P < .001) by JPS than by TTDPM.

CONCLUSION

Proprioception of ACL-injured knees was decreased compared with contralateral intact knees, as determined by both joint movement (kinesthesia) and joint position. The magnitude of loss of proprioception was greater in joint position than in joint movement.

Proprioception in patients with posterior cruciate ligament tears: A meta-analysis comparison of reconstructed and contralateral normal knees

Posterior cruciate ligament (PCL) reconstruction for patients with PCL insufficiency has been associated with postoperative improvements in proprioceptive function due to mechanoreceptor regeneration. However, it is unclear whether reconstructed PCL or contralateral normal knees have better proprioceptive function outcomes. This meta-analysis was designed to compare the proprioceptive function of reconstructed PCL or contralateral normal knees in patients with PCL insufficiency. All studies that compared proprioceptive function, as assessed with threshold to detect passive movement (TTDPM) or joint position sense (JPS) in PCL reconstructed or contralateral normal knees were included. JPS was calculated by reproducing passive positioning (RPP). Five studies met the inclusion/exclusion criteria for the meta-analysis. The proprioceptive function, defined as TTDPM (95% CI: 0.25 to 0.51°; P<0.00001) and RPP (95% CI: 0.19 to 0.45°; P<0.00001), was significantly different between the reconstructed PCL and contralateral normal knees. The mean difference in angle of error between the reconstructed PCL and contralateral normal knees was 0.06° greater in TTDPM than by RPP. In addition, results from subgroup analyses, based on the starting angles and the moving directions of the knee, that evaluated TTDPM at 15° flexion to 45° extension, TTDPM at 45° flexion to 110° flexion, RPP in flexion, and RPP in extension demonstrated that mean angles of error were significantly greater, by 0.38° (P = 0.0001), 0.36° (P = 0.02), 0.36° (P<0.00001), and 0.23° (P = 0.04), respectively, in reconstructed PCL than in contralateral normal knees. The proprioceptive function of PCL reconstructed knees was decreased, compared with contralateral normal knees, as determined by both TTDPM and RPP. In addition, the amount of loss of proprioception was greater in TTDPM than in RPP, even with minute differences. Results from subgroup analysis, that evaluated the mean angles of error in moving directions through RPP, suggested that the moving direction of flexion has a significantly greater mean for angles of error than the moving direction of extension. Although the level of differences between various parameters were statistically significant, further studies are needed to determine whether the small differences (>1°) of the loss of proprioception are clinically relevant.

Validity and reliability of a novel instrumented one-legged hop test in patients with knee injuries

BACKGROUND

Conventional one-legged hop tests simply evaluate the total hop distance, thus neglecting important temporal and spatial parameters related to the strategy of execution, such as foot contact time.

AIM

To examine the validity and reliability of an instrumented one-legged hop test, the "four hops, three contacts" (4H3C) test, in patients with knee injuries.

METHODS

The 4H3C test consists of four consecutive one-legged hops, of which individual hop distance and foot contact time are recorded by a validated floor-based photocell system. We examined the test-retest reliability, discriminant validity (involved vs. uninvolved side) and convergent validity (relation with maximal voluntary strength) of consecutive hop distance and foot contact time parameters in 50 patients with unilateral knee injuries.

RESULTS

Test-retest reliability was very high for hop distance (intraclass correlation coefficients: 0.91 to 0.97) and high for contact time variables (intraclass correlation coefficients: 0.75 to 0.88). The difference between the involved and the uninvolved side was significant for all hop distance and contact time parameters (p<0.05). Maximal voluntary strength was correlated to both hop distance (r=0.67; p<0.001) and contact time (r=-0.42; p<0.01) variables.

CONCLUSION

The 4H3C is a valid and reliable test for the evaluation of single hops in patients with knee injuries and may be useful in sport and clinical settings. The interpretation of foot contact time data requires however some caution.

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

BACKGROUND

Following an ACL injury, reconstruction (ACL-R) and rehabilitation, athletes may return to play with a proprioceptive deficit. However, literature is lacking to support this hypothesis in elite athletic groups who have returned to international levels of performance. It is possible the potentially heightened proprioceptive ability evidenced in athletes may negate a deficit following injury. The purpose of this study was to consider the effects of ACL injury, reconstruction and rehabilitation on knee joint position sense (JPS) on a group of elite athletes who had returned to international performance.

METHODS

Using a cross-sectional design ten elite athletes with ACL-R and ten controls were evaluated. JPS was tested into knee extension and flexion using absolute error scores. Average data with 95% confidence intervals between the reconstructed, contralateral and uninjured control knees were analyzed using t-tests and effect sizes.

RESULTS

The reconstructed knee of the injured group demonstrated significantly greater angle of error scores when compared to the contralateral and uninjured control into knee flexion (p=0.0001, r=0.98) and knee extension (p=0.0001, r=0.91). There were no significant differences between the contralateral uninjured knee of the injured group and the uninjured control group.

CONCLUSIONS

Elite athletes who have had an ACL injury, reconstruction, rehabilitation and returned to international play demonstrate lower JPS ability compared to control groups. It is unclear if this deficiency affects long-term performance or secondary injury and re-injury problems. In the future physical therapists should monitor athletes longitudinally when they return to play.

Index of fatigue quadriceps in soccer athletes after anterior cruciate ligament reconstruction

OBJECTIVE

The present study aimed to evaluate the muscle fatigue of the quadriceps muscle in high-performance soccer players undergoing (anterior cruciate ligament) ACL reconstruction.

METHODS

We evaluated 17 high-performance soccer players from three professional soccer teams of a state in Brazil from August 2011 to July 2012. All subjects were evaluated between 5.5 and 7 months after ACL reconstruction with a Biodex® isokinetic dynamometer (System 4 Pro) with test protocol CON/CON at 60°/s and 300°/s with 5 and 15 repetitions, respectively. In the calculation of local muscle fatigue, the fatigue index was used, which is calculated by dividing the labor done in the first one-third of the repetitions by that done at the final one-third of the repetitions, and multiplying by 100 to express a unit in percentage (i.e., as a discrete quantitative variable).

RESULTS

All subjects were male, with a mean age of 21.3 ± 4.4 years and mean BMI 23.4 ± 1.53 cm; left dominance was observed in 47% (n = 8) of athletes, and right dominance, in 53% (n = 9) of athletes; and the limb involved in the lesion was the dominant in 29% (n = 5) and the non-dominant in 71% (n = 12). Fatigue rates were 19.6% in the involved limb and 29.0% in the non-involved limb.

CONCLUSION

The results allow us to conclude that there was no significant difference between the limbs involved and not in ACL injuries regarding local muscle fatigue. No association was observed between the dominant side and the limb involved in the ACL injury.

THE EFFECT OF CONSERVATIVELY TREATED ACL INJURY ON KNEE JOINT POSITION Sense

BACKGROUND

Proprioception is critical for effective movement patterns. However, methods of proprioceptive measurement in previous research have been inconsistent and lacking in reliability statistics making it applications to clinical practice difficult. Researchers have suggested that damage to the anterior cruciate ligament (ACL) can alter proprioceptive ability due to a loss of functioning mechanoreceptors. The majority of patients opt for reconstructive surgery following this injury. However, some patients chose conservative rehabilitation options rather than surgical intervention.

PURPOSE

The purpose of this study was to determine the effect of ACL deficiency on knee joint position sense following conservative, non-operative treatment and return to physical activity. A secondary purpose was to report the reliability and measurement error of the technique used to measure joint position sense, (JPS) and comment on the clinical utility of this measurement.

STUDY DESIGN

Observational study design using a cross-section of ACL deficient patients and matched uninjured controls.

METHODS

Twenty active conservatively treated ACL deficient patients who had returned to physical activity and twenty active matched controls were included in the study. Knee joint position sense was measured using a seated passive-active reproductive angle technique. The average absolute angle of error score, between 10 °-30 ° of knee flexion was determined. This error score was derived from the difference between the target and repositioning angle.

RESULTS

The ACL deficient patients had a greater error score (7.9 °±3.6) and hence poorer static proprioception ability that both the contra-lateral leg (2.0 °±1.6; p = 0.0001) and the control group (2.6 °±0.9; p = 0.0001). The standard error of the mean (SEM) of this JPS technique was 0.5 ° and 0.2 ° and the minimum detectable change (MDC) was 1.3 ° and 0.4 ° on asymptomatic and symptomatic subjects respectively.

CONCLUSION

This study confirms a static proprioceptive deficiency exists in the knee joint following ACL injury and rehabilitation, potentially due to a reduction in functioning mechanoreceptors in the ligament over time. The differences between the ACL deficient knee and the control group were above the SEMs and MDCs of the measurement which suggests clinical relevance. Longitudinal studies are needed to evaluate if patients who return to activity with a joint position sense deficiency develop secondary injuries.

LEVELS OF EVIDENCE

Individual Cohort Study (2b).

Effects of neuromuscular training on knee joint stability after anterior cruciate ligament reconstruction

[Purpose] This study examined the effects of neuromuscular training on knee joint stability after anterior cruciate ligament reconstruction. [Subjects and Methods] The subjects were 16 adults who underwent arthroscopic anterior cruciate reconstruction and neuromuscular training. The Lysholm scale was used to assess functional disorders on the affected knee joint. A KT-2000 arthrometer was used to measure anterior displacement of the tibia against the femur. Surface electromyography was used to detect the muscle activation of the vastus medialis oblique, vastus lateralis, biceps femoris, and semitendinosus before and after neuromuscular training. [Results] There was significant relaxation in tibial anterior displacement of the affected and sound sides in the supine position before neuromuscular training. Furthermore, the difference in the tibial anterior displacement of the affected knee joints in the standing position was reduced after neuromuscular training. Moreover, the variation of the muscle activation evoked higher muscle activation of the vastus medialis oblique, vastus lateralis, biceps femoris, and semitendinosus. [Conclusion] Neuromuscular training may improve functional joint stability in patients with orthopedic musculoskeletal injuries in the postoperative period.

Association between sensory function and medio-lateral knee position during functional tasks in patients with anterior cruciate ligament injury

BACKGROUND

Patients with anterior cruciate ligament (ACL) injury often exhibit reduced movement quality during functional tasks in the form of a knee-medial-to-foot position (KMFP). This movement pattern is suggested to be more common in women than in men, but the possible contributing sensorimotor factors for this altered knee position are poorly studied in these patients. The aim of this study was to evaluate the association between sensory function and medio-lateral knee position during functional tasks in men and women with ACL injury.

METHODS

Fifty-one patients (23 women) aged 18-40 years with ACL injury were included in this cross-sectional study. Measures of sensory function were assessed by the threshold to detection of passive motion (TDPM) for knee kinesthesia and by the vibration perception threshold (VPT) for vibration sense. Movement quality was assessed by visual observation of the position of the knee relative to the foot during the following four functional tasks with different degrees of difficulty: the single-limb mini-squat, stair descending, the forward lunge, and the drop-jump. Spearman's rank correlation coefficient was used to determine the relationship between the sensory measures and the medio-lateral knee position during the functional tasks. Differences in TDPM and/or VPT between subjects with good and poor movement quality were evaluated using the independent t-test. Separate gender analyses were performed.

RESULTS

Worse TDPM was associated with a KMFP during the drop jump in men. Worse VPT at the toe and ankle was associated with a KMFP during stair descending and the forward lunge in women, but no associations were found in men.

CONCLUSION

Worse kinesthesia, measured by TDPM, might be associated with KMFP during the drop jump in men with ACL injury while worse vibration sense, measured by the VPT, at the foot and ankle might be related to KMFP in women. Further studies are needed to confirm these results.

Motion alterations after anterior cruciate ligament reconstruction: comparison of the injured and uninjured lower limbs during a single-legged jump

CONTEXT

Asymmetries subsist after anterior cruciate ligament reconstruction (ACL-R), and it is unclear how lower limb motion is altered in the context of a dynamic movement.

OBJECTIVE

To highlight the alterations observed in the injured limb (IL) during the performance of a dynamic movement after ACL-R.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 11 men (age = 23.3 ± 3.8 years, mass = 81.2 ± 17.0 kg) who underwent ACL-R took part in this study 7.3 ± 1.1 months (range = 6-9 months) after surgery.

INTERVENTION(S)

Kinematic and kinetic analyses of a single-legged squat jump were performed. The uninjured leg (UL) was used as the control variable.

MAIN OUTCOME MEASURE(S)

Kinematic and kinetic variables.

RESULTS

Jump height was 24% less for the IL than the UL (F1,9 = 23.3, P = .001), whereas the push-off phase duration was similar for both lower limbs (P = .96). Knee-joint extension (F₁,₉ = 11.4, P = .009), and ankle plantar flexion (F₁,₉ = 22.6, P = .001) were less at takeoff for the IL than the UL. The hip angle at takeoff was not different between lower limbs (P = .09). We found that total moment was 14% less (F₁,₉ = 11.1, P = .01) and total power was 35% less (F₁,₉ = 24.2, P = .001) for the IL than the UL. Maximal hip (P = .09) and knee (P = .21) power was not different between legs. The IL had 34% less maximal ankle power (F₁,₉ = 11.3, P = .009) and 31% less angular velocity of ankle plantar flexion (F₁,₉ = 17.8, P = .004) than the UL.

CONCLUSIONS

At 7.3 months after ACL-R, motion alterations were present in the IL, leading to a decrease in dynamic movement performance. Enhancing the tools for assessing articular and muscular variables during a multijoint movement would help to individualize rehabilitation protocols after ACL-R.

Single-bundle versus double-bundle anterior cruciate ligament reconstruction: assessment with vertical jump test

PURPOSE

The study was designed to compare the clinical results of traditional single-bundle (SB) anterior cruciate ligament (ACL) reconstruction with those of double-bundle (DB) ACL reconstruction.

METHODS

This study comprised 80 patients aged 18 to 45 years with an isolated ACL lesion: 40 patients underwent SB reconstruction, and 40 patients underwent DB reconstruction. Patients were assessed preoperatively with functional assessment including the International Knee Documentation Committee 2000 knee subjective form and visual analog scale, as well as physical examination (including the pivot-shift test and instrumented knee laxity measurement). Vertical jump assessment with the Optojump system (Microgate, Bolzano, Italy) has been introduced as a method to compare functional ability between the 2 surgical techniques. The same protocol was repeated 6 months, 12 months, and 2 years after surgery.

RESULTS

No statistically significant differences were noted between the groups concerning subjective evaluation, thigh girth difference, mean visual analog scale score, range of motion, and Lachman and anterior drawer tests (P = not significant). A statistically higher number of patients in the SB group showed a positive pivot-shift test and a higher side-to-side difference when measured with the KT-1000 arthrometer (MEDmetric, San Diego, CA) than in the DB group (P < .001). Better mean jumping performance results were reported in the DB group compared with the SB group (P < .001). The average performance results for the injured limb were not significantly reduced compared with those of the uninjured limb in the DB group 12 months after surgery. At 2 years, a restoration of jumping ability in the ACL-reconstructed limb was achieved in both groups regardless of the technique used.

CONCLUSIONS

DB ACL reconstruction has been proven to be superior to the SB technique with regard to knee stability and vertical jump performance.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Military exercises, knee and ankle joint position sense, and injury in male conscripts: a pilot study

CONTEXT

The high incidence of lower limb injuries associated with physical exercises in military conscripts suggests that fatigue may be a risk factor for injuries. Researchers have hypothesized that lower limb injuries may be related to altered ankle and knee joint position sense (JPS) due to fatigue.

OBJECTIVE

To evaluate if military exercises could alter JPS and to examine the possible relation of JPS to future lower extremity injuries in military service.

DESIGN

Cohort study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 50 male conscripts (age = 21.4 ± 2.3 years, height = 174.5 ± 6.4 cm, mass = 73.1 ± 6.3 kg) from a unique military base were recruited randomly. main outcome measure(s): Participants performed 8 weeks of physical activities at the beginning of a military course. In the first part of the study, we instructed participants to recognize predetermined positions before and after military exercises so we could examine the effects of military exercise on JPS. The averages of the absolute error and the variable error of 3 trials were recorded. We collected data on the frequency of lower extremity injuries over 8 weeks. Next, the participants were divided into 2 groups: injured and uninjured. Separate 2 × 2 × 2 (group-by-time-by-joint) mixed-model analyses of variance were used to determine main effects and interactions of these factors for each JPS measure. In the second part of the study, we examined whether the effects of fatigue on JPS were related to the development of injury during an 8-week training program. We calculated Hedges effect sizes for JPS changes postexercise in each group and compared change scores between groups.

RESULTS

We found group-by-time interactions for all JPS variables (F range = 2.86-4.05, P < .01). All participants showed increases in JPS errors postexercise (P < .01), but the injured group had greater changes for all the variables (P < .01).

CONCLUSIONS

Military conscripts who sustained lower extremity injuries during an 8-week military exercise program had greater loss of JPS acuity than conscripts who did not sustain injuries. The changes in JPS found after 1 bout of exercise may have predictive ability for future musculoskeletal injuries.

Intra and intersession reliability of a postural control protocol in athletes with and without anterior cruciate ligament reconstruction: a dual-task paradigm

BACKGROUND

Quantification of dynamic balance is essential to assess a patient's level of injury or ability to function so that a proper plan of care may commence. In spite of comprehensive utilization of dual-tasking in balance assessment protocols, a lack of sufficient reliability data is apparent.

PURPOSE

The purpose of the present study was to determine the intra- and inter-session reliability of dynamic balance measures obtained using the Biodex Balance System® (BBS) for a group of athletes who had undergone anterior cruciate ligament reconstruction (ACLR) and a matched control group without ACLR, while using a dual-task paradigm.

METHODS

Single-limb postural stability was assessed in 15 athletes who had undergone ACLR and 15 healthy matched controls. The outcome variables included measures of both postural and cognitive performance. For measuring postural performance, the overall stability index (OSI), anterior-posterior stability index (APSI), and medial-lateral stability index (MLSI), were recorded. Cognitive performance was evaluated by measuring error ratio and average reaction time. Subjects faced 4 postural task difficulty levels (platform stabilities of 8 and 6 with eyes open and closed), and 2 cognitive task difficulty levels (with or without auditory Stroop task). During dual task conditions (conditions with Stroop task), error ratio and average reaction time were calculated.

RESULTS

Regarding intrasession reliability, ICC values of test session were higher for MLSI [ACL-R group (0.83-0.95), control group (0.71-0.95)] compared to OSI [ACL-R group (0.80-0.92), control group (0.67-0.95)] and APSI [ACL-R group (0.73-0.90), control group (0.62-0.90)]. Furthermore, ICC values of first test session were higher in reaction time [ACL-R group (0.92-0.95), control group (0.80-0.92)] than error ratio [ACL-R group (0.72-0.88), control group (0.61-0.83)]. ICC values of retest session were higher for MLSI [ACL-R group (0.83-0.94), control group (0.87-0.93)] than OSI [ACL-R group (0.81-0.91), control group (0.83-0.93)] and APSI [ACL-R group (0.73-0.90), control group (0.53-0.90)]. Moreover, ICC values of retest session were higher in reaction time [ACL-R group (0.89-0.98), control group (0.80-0.92)] equated with error ratio [ACL-R group (0.73-0.87), control group (0.57-0.79)]. With respect to intersession reliability, ICC values were higher for MLSI [ACL-R group (0.72-0.96), control group (0.75-0.92)] than OSI [ACL-R group (0.55-0.91), control group (0.64-0.87)] and APSI [ACL-R group (0.55-0.79), control group (0.46-0.89)]. Additionally, ICC values were higher in reaction time [ACL-R group (0.87-0.95), control group (0.68-0.81)] in contrast to error ratio [ACL-R group (0.42-0.64), control group (0.54-0.74)].

CONCLUSION

Biodex Balance System® measures of postural stability demonstrated moderate to high reliability in athletes with and without ACLR during dual-tasking. Results of the current study indicated that assessment of postural and cognitive performance in athletes with ACLR may be reliably incorporated into the evaluation of functional activity.

LEVEL OF EVIDENCE

2b.

Rehabilitation after anterior cruciate ligament reconstruction: a systematic review

BACKGROUND

Rigorous rehabilitation after anterior cruciate ligament (ACL) reconstruction is necessary for a successful surgical outcome. A large number of clinical trials continue to assess aspects of this rehabilitation process. Prior systematic reviews evaluated fifty-four Level-I and II clinical trials published through 2005.

METHODS

Eighty-five articles from 2006 to 2010 were identified utilizing multiple search engines. Twenty-nine Level-I or II studies met inclusion criteria and were evaluated with use of the CONSORT (Consolidated Standards of Reporting Trials) criteria. Topics included in this review are postoperative bracing, accelerated strengthening, home-based rehabilitation, proprioception and neuromuscular training, and six miscellaneous topics investigated in single trials.

RESULTS

Bracing following ACL reconstruction remains neither necessary nor beneficial and adds to the cost of the procedure. Early return to sports needs further research. Home-based rehabilitation can be successful. Although neuromuscular interventions are not likely to be harmful to patients, they are also not likely to yield large improvements in outcomes or help patients return to sports faster. Thus, they should not be performed to the exclusion of strengthening and range-of-motion exercises. Vibration training may lead to faster and more complete proprioceptive recovery but further evidence is needed.

CONCLUSIONS

Several new modalities for rehabilitation after ACL reconstruction may be helpful but should not be performed to the exclusion of range-of-motion, strengthening, and functional exercises. Accelerated rehabilitation does not appear to be harmful but further investigation of rehabilitation timing is warranted.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Effects of knee bracing on postural control after anterior cruciate ligament rupture

STUDY DESIGN

Randomized clinical trial.

OBJECTIVES

To investigate the effects of functional knee braces on postural control in patients with anterior cruciate ligament (ACL) rupture.

BACKGROUND

ACL rupture leads to both mechanical knee instability and deficits in proprioception. Although elastic knee braces do not increase mechanical stability, patients report improved stability when wearing a brace. Elastic braces were found to reduce the loss of proprioception. It is, however, still unclear whether they also improve postural control, which involves the processing of proprioceptive input at a higher level.

METHODS

We studied 58 patients with isolated unilateral ACL rupture using computerized dynamic posturography and compared overall stability index (OSI) scores for injured and uninjured legs with and without a knee brace. In addition, patients were classified as copers and non-copers depending on knee function.

RESULTS

Within subjects, OSI scores were 3.0 ± 1.1° for uninjured legs when unbraced, 2.8±1.3° for uninjured legs when braced (p=0.17), 3.7 ± 1.5° for unbraced injured legs, and 2.9 ± 1.3° for braced injured legs (p<0.001). For the injured legs of copers and non-copers, OSI scores were 3.4° ± 1.2° for copers and 4.0° ± 1.6° for non-copers in the unbraced condition (p=0.11) and 2.7 ± 1.0° for copers and 3.1 ± 1.4° for non-copers in the braced condition (p=0.26).

CONCLUSION

Elastic knee braces increase postural stability by approximately 22% in patients with ACL rupture. There was no difference in postural stability between uninjured and injured legs in the braced condition. One possible explanation is that bracing improves both proprioception and postural control.

Arthroscopic evaluation of preserved ligament remnant after selective anteromedial or posterolateral bundle anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to evaluate the clinical results and morphology of the preserved bundle remnants by second-look arthroscopy postoperatively 1 year after selective anteromedial (AM) or posterolateral (PL) bundle ACL reconstruction.

METHODS

Between July 2004 and September 2009, 1,000 patients underwent arthroscopic anterior cruciate ligament (ACL) reconstruction at our hospital. Among them, 20 (2%) underwent selective AM bundle (group A) or PL bundle (group P) ACL reconstruction surgery with hamstring tendon autografts. At 1 year after surgery, 19 patients (7 male and 12 female patients; age range, 15 to 57 years) underwent second-look arthroscopic evaluations. The follow-up mean was 40.2 months (range, 24 to 70 months). We evaluated the results of manual knee laxity, anterior knee laxity measured by a Telos device (Telos, Marburg, Germany) at 130 N, Lysholm scores, and International Knee Documentation Committee evaluation form and performed evaluations of morphology by second-look arthroscopy.

RESULTS

The side-to-side difference in anterior translation by use of the Telos device at 130 N was improved to 2 ± 2 mm (postoperatively) from 6 ± 2.3 mm (preoperatively) in group A and to 1.02 ± 1.26 mm from 4.93 ± 1.73 mm in group P. By second-look arthroscopy, the graft and preserved remnant of each case was considered to have acceptable synovial coverage and to be taut.

CONCLUSIONS

The preserved ACL remnants possess acceptable morphology and the functions of anterior-posterior and rotational stability after surgery. Our procedure can be recommended for surgery on partial ACL tears.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Neuromuscular efficiency of the vastus medialis obliquus and postural balance in professional soccer athletes after anterior cruciate ligament reconstruction

The purpose of this study was to evaluate the neuromuscular efficiency of the vastus medialis obliquus and postural balance in high-performance soccer athletes after anterior cruciate ligament (ACL) reconstruction, compared to the uninvolved leg. A cross-sectional study was conducted with 22 male professional soccer players after ACL reconstruction (4-12 months postoperatively). The athletes were submitted to functional rehabilitation with an accelerated protocol on the soccer team. They were evaluated using isokinetic dynamometer, surface electromyography and electronic baropodometer. There was no decrease or difference between neuromuscular efficiency of the VMO when comparing both the limbs after ACL reconstruction in the professional soccer athletes under treatment. The same result was found in postural balance. It can be concluded that the NME of the VMO in the involved member and postural balance were successfully re-established after the reconstruction procedure of the ACL in the sample group studied.

Synovialization on second-look arthroscopy after anterior cruciate ligament reconstruction using Achilles allograft in active young men

PURPOSE

This study is to assess the relationship between clinical outcomes and the extent of synovialization through second-look arthroscopy for anterior cruciate ligament (ACL) reconstruction using Achilles allograft in active young men.

METHODS

Ninety-five subjects were diagnosed with ACL rupture and underwent reconstruction with Achilles allograft. Median age was 22 years old (range, 17-40). Mean period from injury to operation was 15.1 ± 18.2 weeks. Lysholm score, IKDC classification, range of motion (ROM) of knee, and side-to-side difference (SSD) in anterior instability were evaluated preoperatively and at the last follow-up. Tegner activity scale was evaluated before injury and at the final follow-up. The extent of synovialization of the graft was evaluated under second-look arthroscopy at least 1 year after surgery. Formation of the synovial membrane was divided into four groups-group 1 for 25% or less, group 2 for 25-50%, group 3 for 50-75%, and group 4 for more than 75%. Outcomes were compared between each group.

RESULTS

Lysholm score and IKDC classification were improved after surgery (P < 0.05). Most subjects had full ROM at the final follow-up except three subjects that showed flexion deficit of 5 degrees or less. Mean SSD in anterior instability was 9.0 ± 2.1 mm preoperatively and 1.6 ± 2.0 mm at the final follow-up (P < 0.001). Median Tegner activity scale was 7 before injury and 7 at the final follow-up (P < 0.001). Twelve subjects were in group 1, 10 in group 2, 14 in group 3, and 59 in group 4. Clinical outcomes depending on the extent of synovialization of the grafts were different between each group (P < 0.05). The average period from injury to reconstruction in each group was significantly different (P < 0.001). Correlation coefficient between the period from injury to reconstruction and the extent of synovialization was -0.411 (P < 0.001).

CONCLUSION

The extent of the synovialization is positively correlated with clinical outcomes and is negatively correlated with the period from injury to reconstruction.

Extension and flexion torque variability in ACL deficiency

PURPOSE

To evaluate possible differences in knee extension and flexion torque variability in the anterior cruciate ligament-deficient (ACLD) leg and their dependence on muscle length and visual feedback (VF). Although a knee extension torque deficit is found in the ACLD leg, there is no evidence that variability in submaximal isometric knee extension and flexion torque is affected in the ACLD leg or that it depends on VF.

METHODS

All tests were performed using 13 untrained men with unilateral ACL rupture. Isometric knee extension torques at 90(o) and 120(o) and knee flexion torques at 90(o), 120(o) and 140(o) were evaluated in healthy and ACLD legs. Isometric torque variability at 20% of maximal force was evaluated with or without VF. The coefficients of variation (CV) and permutation entropies (PE) were used to calculate submaximal isometric torque variability.

RESULTS

Healthy legs had significantly greater isometric torques at 90(o) and 120(o) knee angles during knee extension compared with ACLD legs. There were no differences between healthy and ACLD legs in torque variability in knee extension and flexion with or without VF. The PE of knee extension torque at knee angles of 90(o) and 120(o) was significantly (P < 0.05) greater in healthy legs.

CONCLUSIONS

The effect of ACL deficiency on variability (CV) in submaximal isometric knee extension and flexion torque was not significant. However, PE of knee extension submaximal torque was significantly greater in the healthy leg than in the ACLD leg. When estimating ACL deficit, it is important to measure not only isometric maximal torque but also torque variability and complexity using nonlinear tool during submaximal isometric tasks.

LEVEL OF EVIDENCE

III.

Laboratory evaluation of the pivot-shift phenomenon with use of kinetic analysis: a preliminary study

BACKGROUND

Currently, a suitable and reliable noninvasive method to evaluate rotational stability in vivo in anterior cruciate ligament-deficient knees, particularly during sports movements, does not exist. We speculated that if there is a rotational instability, the patient would avoid reaching a high pivoting moment during pivoting activities as a defense mechanism, and that the ground reaction moment, as registered by dynamometric platforms, would be reduced. On the basis of this hypothesis, we developed a study using kinetic analysis to evaluate rotational stability under dynamic loading.

METHODS

Thirty recreationally active athletes, including fifteen healthy subjects and fifteen with an anterior cruciate ligament-deficient knee, were recruited for this study. Patients performed jumping with pivoting with internal tibial rotation and external tibial rotation on the dynamometric platform with both the healthy and the injured limb. The quantitative results were graphically plotted, and the following parameters were evaluated: loading moment, pivoting moment, torque amplitude, loading slope, pivoting slope, percentage of pivoting with load, loading impulse, pivoting impulse, and maximum body rotation angle.

RESULTS

There were no significant differences between the dominant and nondominant knees in the control group during the jumping with pivoting and external tibial rotation test with regard to the pivoting moment (p = 0.805), pivoting slope (p = 0.716), pivoting impulse 2 (p = 0.858), and pivoting impulse 3 (p = 0.873). In patients with a chronic tear of the anterior cruciate ligament, there was a significant decrease of the pivoting moment (p = 0.02), pivoting slope (p = 0.005), pivoting impulse 2 (p = 0.006), and pivoting impulse 3 (p = 0.035) during the jumping with pivoting and external tibial rotation test in the anterior cruciate ligament-deficient knee compared with the healthy, contralateral knee.

CONCLUSION

Kinetic analysis with use of a dynamic platform can objectively detect alterations of rotational stability in anterior cruciate ligament-deficient knees, which may allow this to be a useful research tool for evaluating treatment strategies in patients with anterior cruciate ligament injuries.

Knee proprioception following ACL reconstruction; a prospective trial comparing hamstrings with bone-patellar tendon-bone autograft

We prospectively studied knee proprioception following ACL reconstruction in 40 patients (34 men and six women; mean age 31 years). The patients were allocated into two equal groups; group A underwent reconstruction using hamstrings autograft, and group B underwent reconstruction using bone-patellar tendon-bone autograft. Proprioception was assessed in flexion and extension by the joint position sense (JPS) at 15°, 45° and 75°, and time threshold to detection of passive motion (TTDPM) at 15° and 45°, preoperatively and at 3, 6 and 12 months postoperatively. The contralateral healthy knee was used as internal control. No statistical difference was found between the ACL-operated and the contralateral knees in JPS 15°, 45° and 75° at 6 and 12 months, in both study groups. No statistical difference was found between the ACL-operated and the contralateral knees in TTDPM 15° at 6 and 12 months, nor regarding TTDPM 45° at 3, 6 and 12 months, in group A. No statistical difference was found in JPS and TTDPM between the two grafts, at any time period. Knee proprioception returned to normal with ACL reconstruction at 6 months postoperatively, without any statistically significant difference between the autografts used.

Cryotherapy and joint position sense in healthy participants: a systematic review

OBJECTIVE

To (1) search the English-language literature for original research addressing the effect of cryotherapy on joint position sense (JPS) and (2) make recommendations regarding how soon healthy athletes can safely return to participation after cryotherapy.

DATA SOURCES

We performed an exhaustive search for original research using the AMED, CINAHL, MEDLINE, and SportDiscus databases from 1973 to 2009 to gather information on cryotherapy and JPS. Key words used were cryotherapy and proprioception, cryotherapy and joint position sense, cryotherapy, and proprioception.

STUDY SELECTION

The inclusion criteria were (1) the literature was written in English, (2) participants were human, (3) an outcome measure included JPS, (4) participants were healthy, and (5) participants were tested immediately after a cryotherapy application to a joint.

DATA EXTRACTION

The means and SDs of the JPS outcome measures were extracted and used to estimate the effect size (Cohen d) and associated 95% confidence intervals for comparisons of JPS before and after a cryotherapy treatment. The numbers, ages, and sexes of participants in all 7 selected studies were also extracted.

DATA SYNTHESIS

The JPS was assessed in 3 joints: ankle (n = 2), knee (n = 3), and shoulder (n = 2). The average effect size for the 7 included studies was modest, with effect sizes ranging from -0.08 to 1.17, with a positive number representing an increase in JPS error. The average methodologic score of the included studies was 5.4/10 (range, 5-6) on the Physiotherapy Evidence Database scale.

CONCLUSIONS

Limited and equivocal evidence is available to address the effect of cryotherapy on proprioception in the form of JPS. Until further evidence is provided, clinicians should be cautious when returning individuals to tasks requiring components of proprioceptive input immediately after a cryotherapy treatment.

Measurement of in vivo anterior cruciate ligament strain during dynamic jump landing

Despite recent attention in the literature, anterior cruciate ligament (ACL) injury mechanisms are controversial and incidence rates remain high. One explanation is limited data on in vivo ACL strain during high-risk, dynamic movements. The objective of this study was to quantify ACL strain during jump landing. Marker-based motion analysis techniques were integrated with fluoroscopic and magnetic resonance (MR) imaging techniques to measure dynamic ACL strain non-invasively. First, eight subjects' knees were imaged using MR. From these images, the cortical bone and ACL attachment sites of the tibia and femur were outlined to create 3D models. Subjects underwent motion analysis while jump landing using reflective markers placed directly on the skin around the knee. Next, biplanar fluoroscopic images were taken with the markers in place so that the relative positions of each marker to the underlying bone could be quantified. Numerical optimization allowed jumping kinematics to be superimposed on the knee model, thus reproducing the dynamic in vivo joint motion. ACL length, knee flexion, and ground reaction force were measured. During jump landing, average ACL strain peaked 55±14 ms (mean and 95% confidence interval) prior to ground impact, when knee flexion angles were lowest. The peak ACL strain, measured relative to its length during MR imaging, was 12±7%. The observed trends were consistent with previously described neuromuscular patterns. Unrestricted by field of view or low sampling rate, this novel approach provides a means to measure kinematic patterns that elevate ACL strains and that provide new insights into ACL injury mechanisms.

[Isokinetic, functional and proprioceptive assessment of soccer players two years after surgical reconstruction of the anterior cruciate ligament of the knee]

Injuries to the anterior cruciate ligament (ACL) of the knee are common in sport and are treated routinely in the world of sports medicine. In order to resume competitive sport in safety, it is important to know the actual level of performance achieved by the operated leg some time after the ligament repair.

OBJECTIVES

The objective of this work was to evaluate the recovery of the operated leg in Tunisian sportsmen two years after surgery by using isokinetic testing (60 degrees s(-1)), the one-leg hop distance test (i.e. a functional activity that one often finds in sport) and proprioceptive assessment. A secondary objective was to detect any possible correlations between the various outcomes.

MATERIALS AND METHOD

The ACL group was composed of 26 top-level Tunisian footballers having undergone ACL ligament repair. Two years after surgery, the following assessments were performed: an isokinetic test with an angular velocity of 60 degrees s(-1), a proprioceptive assessment in both active and passive modes and the functional one-leg hop distance test.

RESULTS

Our investigations confirmed a muscle deficit of 16% in the hamstring muscles of the injured leg. In both active and passive modes, normal proprioception is observed at a flexion of 60 degrees and in total extension but not in a mid-way position. The performance level of the operated leg (in terms of distance) had an average symmetry value of 93.40+/-2.7%.

CONCLUSION

Playing football appears to influence the isokinetic strength profile in sportsmen after ACL repair. The repair procedure leads to bilateral proprioceptive disruption at 15 degrees of knee flexion, on average.

Changed cortical activity after anterior cruciate ligament reconstruction in a joint position paradigm: an EEG study

After reconstruction of the anterior cruciate ligament (ACL) afferent proprioceptive information from the knee joint may be altered. In order to examine changes in central activation patterns, spectral features of the electroencephalography (EEG) were measured. Patients after ACL reconstruction and healthy controls carried out an knee-angle reproduction task in a groups x limbs x trials design. Cortical activity was recorded using international standards. FFT were conducted to determine power at Theta, Alpha-1, Alpha-2 and Beta-1. Statistics show significantly larger aberrations in the reconstructed limbs compared with the controls whereas there are no differences between the uninvolved land controls. Brain activity demonstrates significantly higher frontal Theta-power (F3, F4, F8) in both limbs of the ACL group vs the controls and a significantly higher Alpha-2 power was shown in the ACL-reconstructed limb compared with controls at parietal positions (P3, P4). No such differences were found between the uninvolved side and the controls. The EEG was able to measure a change in joint position sense at the cortical level after the reconstruction of the ACL. The results of these findings might indicate differences in focused attention with involvement of the anterior cingulate cortex (frontal Theta) and sensory processing in the parietal somatosensory cortex (Alpha-2).

Proprioceptive skills and functional outcome after anterior cruciate ligament reconstruction with a bone-tendon-bone graft

Several studies have shown that patients with anterior cruciate ligament (ACL) reconstruction have an improved proprioceptive function compared to subjects with ACL-deficient knees. The measurement of functional scores and proprioception potentially provides clinicians with more information on the status of the ACL-reconstructed knees. To evaluate proprioception in patients following ACL reconstruction with a bone-tendon-bone (BTB) graft, we used the angle reproduction in the sitting, lying and standing positions and the one-leg hop test. Forty-five patients between 19 and 52 years of age were investigated in a 36-month period after the operation. For functional performance measurement, the International Knee Documentation Committee (IKDC) score was used. Very good and good results were seen in 95% of cases. All patients returned to the same activity level as seen before ACL repair. There was a significant difference in the active angle reproduction test between the ACL-reconstructed knees and normal knees in the active sitting position. Tests with passive angle adjustment in the sitting, lying and active standing positions did not show any differences in proprioceptive skills. Good to very good results in the one-leg hop test we found in 95% of patients. After ACL reconstruction, deficiencies in the active angle reproduction test were very small but, nevertheless, were still observed. Overall, the functional and proprioceptive outcomes demonstrate results to recommend the procedure.

The relationship between maximum unilateral squat strength and balance in young adult men and women

The purpose of this study was to determine the relationship between unilateral squat strength and measures of static balance to compare balance performance between the dominant and non-dominant leg. Seventeen apparently healthy men (mean mass 90.5 ± 20.9 kg and age 21.7 ± 1.8 yrs) and 25 women (mean mass 62.2 ± 14.5 kg and age 21.9 ± 1.3 yrs) completed the study. Weight bearing unilateral strength was measured with a 1RM modified unilateral squat on the dominant and non-dominant leg. The students completed the stork stand and wobble board tests to determine static balance on the dominant and non-dominant leg. Maximum time maintained in the stork stand position, on the ball of the foot with the uninvolved foot against the involved knee with hands on the hips, was recorded. Balance was measured with a 15 second wobble board test. No significant correlations were found between the measurements of unilateral balance and strength (r values ranged between -0.05 to 0.2) for the men and women. Time off balance was not significantly different between the subjects' dominant (men 1.1 ± 0.4 s; women 0.3 ± 0.1 s) and non-dominant (men 0.9 ± 0.3 s; women 0.3 ± 0.1 s) leg for the wobble board. Similar results were found for the time balanced during the stork stand test on the dominant (men 26.4 ± 6.3 s; women 24.1 ± 5.6 s) and non-dominant (men 26.0 ± 5.7 s; women 21.3 ± 4.1 s) leg. The data indicate that static balance and strength is unrelated in young adult men and women and gains made in one variable after training may not be associated with a change in performance of the other variable. These results also suggest that differences in static balance performance between legs can not be determined by leg dominance. Similar research is needed to compare contralateral leg balance in populations who participate in work or sport activities requiring repetitive asymmetrical use. A better understanding of contralateral balance performance will help practitioners make evaluative decisions during the rehabilitation process. Key Points1RM unilateral squat strength is unrelated to measures of unilateral static balance in young adult men and womenStatic balance is similar between the dominant and non-dominant leg in young adult men and womenSide-to-side differences in balance warrant assessment and training to correct imbalances prior to participation in activities that present a high risk for injury.

Benefits of active motion for joint position sense

Anterior cruciate ligament (ACL) ruptures lead to a proprioceptive deficit and therefore joint position sense. This study examined whether active motion is better suited than passive motion to address this deficit. Sixty patients with ACL rupture were prospectively randomised into two groups [continuous active motion (CAM)/continuous passive motion (CPM)]. All patients had an ACL reconstruction. An angle reproduction test was used to assess the proprioceptive deficit. The relevant examinations were performed before surgery (pre-op evaluation) and after the seventh postoperative day. No preoperative difference was found between the two groups. After postoperative treatment, the deficit was reduced in both groups. Significantly better results were, however, obtained in the CAM group (CPM, 4.2+/-1.6 degrees; CAM, 1.9+/-1.2 degrees; P<0.001). During the first postoperative week, a CAM device produced a significantly greater reduction in the proprioceptive deficit and should be the first choice in immediately postoperative rehabilitation after ACL replacement.