Proprioception in anterior cruciate ligament deficient knees and its relevance in anterior cruciate ligament reconstruction

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Graft failure and revision rate after ACL repair with dynamic intraligamentary stabilization. One-year results of a prospective case series of 155 patients

PURPOSE

The aim of this study was to assess graft failure, revision rate, and functional outcomes after treatment of acute ACL rupture with dynamic intraligamentary stabilization (DIS) Ligamys device one year post surgery. Additionally, differences in functional outcome between patients with and without anteroposterior laxity were assessed. It was hypothesized that the failure rate of DIS was non-inferior to that of previously reported ACL reconstruction (10%).

METHODS

In this prospectively designed multicenter study, including patients with an acute ACL rupture, DIS was performed within 21 days after rupture. Primary outcome was failure of the graft at 1 year post surgery, defined as 1) re-rupture of the graft, 2) revision of DIS, or 3) a > 3 mm side-to-side difference in anterior tibial translation compared to the non-operated knee (∆ATT), measured by the KT1000 device. Additional analysis was performed using a 5 mm threshold. The subjective International Knee Documentation Committee Score (IKDC) and Numerical Rating Scales (NRS) for pain and confidence were used to evaluate functional outcome.

RESULTS

A total of 155 patients were included with a mean age at surgery of 27.8 years (SD 9.4). The mean interval from rupture to DIS was 16.4 days (SD 5.2). At a median follow-up of 13 months (IQR 12-18) the failure rate of the graft was 30.2% (95%CI:22.0-39.4); 11 patients (7%) required secondary reconstructive surgery and of the 105 patients who attended ATT measurement, 24 patients (23%) had an ∆ATT > 3 mm. Secondary analysis, based on a 5 mm threshold, revealed a failure rate of 22.4% (95%CI: 15.2; 31.1). A total of 39 patients (25%) reported at least one complication, comprising mainly arthrofibrosis, traumatic re-rupture and pain. In these patients, removal of the monoblock was performed in 21 cases (13.5%). At follow-up no significant differences in functional outcomes between patients with ∆ATT > 3 mm and stable ATT were observed.

CONCLUSION

This prospective multicenter study found a high failure rate at one year follow-up of 30% (7% revision surgery and 23% > 3 mm side-to-side difference in anterior tibial translation) in patients treated by primary repair of the ACL with DIS, and did therefore not demonstrate non-inferiority to ACL reconstruction. For patients who did not require secondary reconstructive surgery, this study found good functional outcomes, also in case of persistent anteroposterior knee laxity (∆ATT > 3 mm).

LEVEL OF EVIDENCE

Level IV.

Augmentation with Fibertape Leads to Biomechanically Superior but Similar Clinical Outcomes in ACL Surgeries: Systematic Review and Meta-analysis

Purpose

The current generation has witnessed significant progress in the field of knee arthroscopy. Suture tapes have gained immense popularity due to perceived improved biomechanical support to the graft while it heals. The purpose of the present systematic review is to analyze the biomechanical construct of suture tapes in ACL repairs and reconstructions along with clinical outcomes.

Methods

Cochrane Library, PubMed, and Embase were searched until December 2021. All Biomechanical Studies on animal or cadaver knees that compared construct characteristics of suture tape in ACL repair or reconstruction and clinical studies in English focusing on outcomes following suture tape augmentation in ACL repair or reconstruction were included. The quality of clinical studies using the Modified Coleman Methodology Score (MCMS).

Results

A total of 16 studies biomechanical and 23 clinical studies were included in qualitative synthesis, leaving nine biomechanical studies for final quantitative analyses. Suture tape revealed biomechanical superiority in terms of ultimate strength, stiffness, cyclic displacement, and elongation of graft, while comparing ACLR with internal brace to standard ACLR. No significant difference in retear rates was seen in clinical studies. Clinical score(IKDC score) was found similar in both augmented and non-augmented construct. Similar results were obtained in biomechanical studies.

Conclusion

The use of suture tape as a ligament augmentation in both ACL reconstruction and ACL repair offers more strength, less elongation or displacement, and is biomechanically stable and sound. There is a lack of data to comprehensively comment upon the clinical superiority of the use of internal augmentation. However, a meta-analysis of the retear rates and clinical outcome score revealed similar outcomes between suture tape augmented and nonaugmented groups.

Inhibition of knee joint sensory afferents alters covariation across strides between quadriceps muscles during locomotion

Sport-related injuries to articular structures often alter the sensory information conveyed by joint structures to the nervous system. However, the role of joint sensory afferents in motor control is still unclear. Here, we evaluate the role of knee joint sensory afferents in the control of quadriceps muscles, hypothesizing that such sensory information modulates control strategies that limit patellofemoreal joint loading. We compared locomotor kinematics and muscle activity before and after inhibition of knee sensory afferents by injection of lidocaine into the knee capsule of rats. We evaluated whether this inhibition reduced the strength of correlation between the activity of vastus medialis (VM) and vastus lateralis (VL) both across strides and within each stride, coordination patterns that limit net mediolateral patellofemoral forces. We also evaluated whether this inhibition altered correlations among the other quadriceps muscle activity, the time-profiles of individual EMG envelopes, or movement kinematics. Neither the EMG envelopes nor limb kinematics was affected by the inhibition of knee sensory afferents. This perturbation also did not affect the correlations between VM and VL, suggesting that the regulation of patellofemoral joint loading is mediated by different mechanisms. However, inhibition of knee sensory afferents caused a significant reduction in the correlation between vastus intermedius (VI) and both VM and VL across, but not within, strides. Knee joint sensory afferents may therefore modulate the coordination between the vasti muscles but only at coarse time scales. Injuries compromising joint afferents might result in altered muscle coordination, potentially leading to persistent internal joint stresses and strains.NEW & NOTEWORTHY Sensory afferents originating from knee joint receptors provide the nervous system with information about the internal state of the joint. In this study, we show that these sensory signals are used to modulate the covariations among the activity of a subset of vasti muscles across strides of locomotion. Sport-related injuries that damage joint receptors may therefore compromise these mechanisms of muscle coordination, potentially leading to persistent internal joint stresses and strains.

Evidence of ACL healing on MRI following ACL rupture treated with rehabilitation alone may be associated with better patient-reported outcomes: a secondary analysis from the KANON trial

OBJECTIVES

Evaluate the natural course of anterior cruciate ligament (ACL) healing on MRI within 5 years of acute ACL rupture and compare 2-year and 5-year outcomes based on healing status and treatment group.

METHODS

Secondary analysis of 120 Knee Anterior Cruciate Ligament Nonsurgical vs Surgical Treatment (KANON) trial participants randomised to rehabilitation and optional delayed ACL reconstruction (ACLR) or early ACLR and rehabilitation. ACL continuity on MRI (Anterior Cruciate Ligament OsteoArthritis Score 0-2) was considered evidence of ACL healing. Outcomes included Knee Injury and Osteoarthritis Outcome Score (KOOS), KOOS patient acceptable symptomatic state (PASS) and treatment failure criteria. Linear mixed models were used to estimate adjusted mean differences (95% CIs) in patient-reported sport and recreational function (KOOS-Sport/Rec) and quality of life (KOOS-QOL) at 2 and 5 years, between participants with MRI evidence of ACL healing and those who had (1) no evidence of ACL healing, (2) delayed ACLR or (3) early ACLR.

RESULTS

MRI evidence of ACL healing at 2-year follow-up was observed in 16 of 54 (30%, 95% CI 19 to 43%) participants randomised to optional delayed ACLR. Excluding participants who had delayed ACLR, 16 of 30 (53%, 36-70%) participants managed with rehabilitation-alone displayed MRI evidence of ACL healing. Two-year outcomes were better in the healed ACL group (n=16) compared with the non-healed (n=14) (mean difference (95% CI) KOOS-Sport/Rec: 25.1 (8.6-41.5); KOOS-QOL: 27.5 (13.2-41.8)), delayed ACLR (n=24) (KOOS-Sport/Rec: 24.9 (10.2-39.6); KOOS-QOL: 18.1 (5.4-30.8)) and early ACLR (n=62) (KOOS-Sport/Rec: 17.4 (4.1-30.7); KOOS-QOL: 11.4 (0.0-22.9)) groups. Five-year KOOS-QOL was better in the healed versus non-healed group (25.3 (9.4-41.2)). Of participants with MRI evidence of ACL healing, 63-94% met the PASS criteria for each KOOS subscale, compared with 29-61% in the non-healed or reconstructed groups.

CONCLUSIONS

MRI appearance of ACL healing after ACL rupture occurred in one in three adults randomised to initial rehabilitation and one in two who did not cross-over to delayed ACLR and was associated with favourable outcomes. The potential for spontaneous healing of the ACL to facilitate better clinical outcomes may be greater than previously considered.

TRIAL REGISTRATION NUMBER

ISRCTN84752559.

Effects of body orientation and direction of movement on a knee joint angle reproduction test in healthy subjects: An experimental study

BACKGROUND

Joint position sense test assess patient mobility and proprioceptive ability. Yet, application used under different conditions may biases reproduction error resulting in different therapeutic consequences.

OBJECTIVE

To investigate knee angle reproduction test under different test conditions.

METHODS

25 healthy subjects (mean ± SD, age = 25 ± 2 years, activity level: 9 ± 2 training hours/week) performed knee angle reproduction test in the sitting and prone position, while changing the knee angle starting (i) from flexion and (ii) extension, (iii) inducing vibration on the semitendinosus tendon.

RESULTS

Absolute mean knee angle reproduction error showed significant difference for body position and vibration (Position: 95% CI 0.71 to 2.32; p< 0.001. No Vibration & Vibration: 95% CI -1.71 to -0.12; p= 0.027). Relative knee angle reproduction error was significant different in all conditions (No Vibration & Vibration: 95% CI -3.30 to -0.45; p= 0.010. Body orientation: 95% CI 1.08 to 3.93; p< 0.001. Direction of movement: 95% CI 0.56 to 3.41; p= 0.007).

CONCLUSION

Body orientation and movement direction influence the resulting knee angle reproduction error in healthy subjects. Practitioners are advised to use standardised test procedures when comparing different within- and between-patient results.

TRIAL REGISTRATION

DOI 10.17605/OSF.IO/AFWRP.

Importance of Lower Extremity Muscle Performance and Knee Proprioception During First 60 Degrees of Knee Flexion at Three Months After Anterior Cruciate Ligament Reconstruction

Background: Knee proprioception and neuromuscular control may be important factors contributing to re-injury occurrences. Objectives: To examine lower extremity muscular performance and knee proprioception preoperatively and 3 months after anterior cruciate ligament (ACL) reconstruction. Methods: Twelve participants underwent ACL reconstruction using the hamstring tendon. All participants were assessed for knee proprioceptive sense using an isokinetic dynamometer at 15° and 60° of knee flexion. Lower extremity muscular performance was examined using the single-leg squat test (SLS) with two-dimensional motion analysis in frontal and sagittal planes. Results: Mean absolute error angle at a 15-degree-target angle was significantly lower at three months after ACL reconstruction compared with the preoperative state (P = 0.04). Maximal knee flexion angle of the injured The SLS test showed a lesser knee flexion angle of the injured knee at three months after ACL reconstruction (P = 0.01), and injured knee proprioception at 60 degree-flexion did not significantly improve at the three month-postoperative stage. Conclusions: At three months after ACL reconstruction by hamstring graft tendon, knee proprioceptive sense at an inner range of knee extension improved. However, proprioception at the middle range did not significantly develop. The range of hip and knee motions using SLS related to strength changes that the knee extensor needs to improve, especially in the middle range.

Effect of Nail Grips on Weight Bearing and Limb Function in 30 Dogs 2 Weeks Post Tibial Plateau Leveling Osteotomy

Simple Summary

Devices made to improve mobility are becoming increasingly popular among owners of dogs with orthopedic conditions, but there are few studies investigating their efficacy. Nail grips are commonly used by veterinary rehabilitation practitioners to improve the security of foot placement by increasing nail traction. This study aimed to assess if nail grips would improve mobility outcomes in dogs recovering from knee surgery. The results did not show a significant effect on outcomes during the initial 2-week post-operative period; however, further research is needed to determine if they are useful for other applications.

Abstract

The objective of this study was to assess the functional outcomes of dogs wearing nail grips in the first 2 weeks following tibial plateau leveling osteotomy (TPLO). Thirty dogs were included (n = 13 nail grips and n = 17 sham grips). Visual lameness scores (VLS), total pressure index (TPI), and client-specific outcome measures (CSOMs) were obtained by blinded observers on day 1 and day 14 +/− 3 post TPLO. CSOMs were also obtained on day 7. There were no differences in VLS and TPI between the treatment and sham group on day 14 (p = 0.44 and p = 0.59, respectively) or at any time point. CSOMs assessing walking on slippery flooring, ability to rise, and consistent use of surgical limb on a 5 min walk were also not different between groups (p = 0.78, p = 0.80, and p = 0.63) at any time point. Nail grips were well tolerated in dogs after orthopedic surgery. This study did not demonstrate a benefit for dogs wearing nail grips during the first two weeks after TPLO; however, further studies are warranted.

First detection of primary cilia in injured human anterior cruciate ligament: A pilot study with pathophysiological reflections

The anterior cruciate ligament (ACL) plays a significant role in knee stability, protects the joint under multiple loading conditions and shows complex biomechanics. Beside mechanical stability, the ACL seems to play a crucial role in proprioception, and it is well known, that ACL injuries can cause functional deficits due to decreased proprioception. However, the mechanism of proprioception is not completely understood yet. In this context, primary cilia (PC), which play a significant role in the signaling between the intra- and extracellular space, could be of interest. However, until today, primary cilia are not yet described in human ACL. In total, seven human ACL's underwent transmission electron microscopical examination. Three cadaveric ACL's and four freshly injured ACL's were examined. Single cells of each ACL were examined regarding the presence of axonemes or basal bodies, which represent components of a PC. In total, 276 cells of the cadaveric ACL's and 180 cells of the injured ACL's were examined. Basal bodies could be detected in three of the four specimens of the injured ACL's as well as in one of the three cadaveric ACL's, resulting in a mean positivity of 2.54% in the cadaveric group and 2.78% in the injured group. In case of PC-presence, only one PC per cell could be detected. No statistically significant difference regarding the frequency could be detected between both groups. In this pilot-study, we present for the first time an ultrastructural study of human ACLs with respect to the occurrence of PC and any structural and morphological features of these complex and dynamic cell organelles. PCs are present in almost all non-hematopoietic tissues of the human body. However, there are different reports on the number, incidence, orientation, and morphology of these cell organelles in the respective tissues. Compared to other tissues and ligaments of other species, we found a significantly lower rate of PC positive cells. This observation might represent a tissue-specific characteristic of ACL tissue. However, our observations need to be explored in more detail in further studies.

Effects of proprioceptive training in the recovery of patients submitted to meniscus surgery: systematic review and meta-analysis

OBJECTIVE

To evaluate the effects of proprioceptive training on rehabilitation of knee after arthroscopic partial meniscectomy (APM).

DESIGN

PubMed, EMBASE, The Cochrane Library, Web of Science, China National Knowledge Infrastructure, Technology Periodical Database, WanFang Data and China Biology Medicine were searched until December 2021 for randomised controlled trials.

PARTICIPANTS

Patients who have undergone APM for meniscus injury caused by traumatic tear.

RESULTS

A total of 9 studies with 453 patients were included in this study for meta-analysis, and 2/9 with high quality, 6/9 with moderate quality. Based on very low quality evidence, the pooled effect showed significant improvement for proprioceptive training group in proprioception test (p<0.05, I²=18%), knee extensor muscle strength (p<0.05, I²=29%), knee flexor muscle strength (p<0.05, I²=0%) and knee function score (p<0.05, I²=0%) compared with conventional training group in patients after APM.

CONCLUSION

Based on very low quality, adding proprioceptive training to conventional rehabilitation programmes might be beneficial to promote functional recovery for patients after APM. It is necessary to carry out more samples and higher quality large-scale studies to provide high evidence in the future.

PROSPERO REGISTRATION NUMBER

CRD42020213201.

Alternatives to Knee Braces

Knee braces continue to be a widely utilized piece of medical equipment, ranging from simple over the counter sleeves to more complex functional braces, with the ability to provide electrical stimulation to muscle groups. Despite their popularity, alternatives to knee braces exist for patients who find braces to be ineffective, uncomfortable, cumbersome, or overly expensive. While high-quality studies are lacking for modalities such as neoprene sleeves, compression stockings, and kinesiotaping, there is promising evidence that these interventions can confer an element of stability and pain relief for a variety of knee pathologies both with regard to acute and chronic injuries as well as in the postoperative rehabilitation period. While no "holy grail" exists for the ideal brace, or bracing alternative, it is important for providers to be aware of the options available to patients as well as the current evidence for these various modalities, so that the provider can best guide musculoskeletal care.

Patients Generally May Return to Driving 4 Weeks After Hip Arthroscopy and 6 Weeks After Knee Arthroscopy: A Systematic Review and Meta-analysis

PURPOSE

To consolidate the evidence from the available literature and undertake a meta-analysis to provide a reference for physicians to make evidence-based recommendations to their patients regarding the return to driving after hip or knee arthroscopic procedures.

METHODS

A systematic review was conducted using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The OVID, Embase, and Cochrane databases were searched through June 2020 for articles containing keywords and/or MeSH (Medical Subject Headings) terms "hip arthroscopy" and "knee arthroscopy" in conjunction with "total brake response time" or "reaction time" in the context of automobile driving. A title review and full article review were performed to assess quality and select relevant articles. A meta-analysis of qualifying articles was undertaken.

RESULTS

Eight studies met the inclusion criteria for meta-analysis of brake reaction time (BRT). Meta-analysis of all knee BRTs showed times slower than or equal to baseline BRTs through 5 weeks, with a trend of improving BRTs from 6 to 10 weeks (weeks 8 and 10 were significant, P < .05). Among all hip BRTs, week 2 showed times slower than baseline BRTs, but after week 4, a trend toward faster BRTs was observed through week 8 (week 8 was significant, P < .05).

CONCLUSIONS

BRTs met baseline or control values and continued to improve after 6 weeks after knee arthroscopy and after 4 weeks after hip arthroscopy. On the basis of these results, it would be safe to recommend a return to driving at 6 weeks after knee arthroscopic procedures and 4 weeks after hip arthroscopic procedures.

CLINICAL RELEVANCE

These results can be used by surgeons to base their recommendations on to provide guidance for their patients on the resumption of driving. Although BRT is an important aspect of driving ability, there are additional factors that need to be taken into consideration when making these recommendations, including cessation of opioid analgesics, strength of the surgical limb, and range of motion.

Effect of Remnant Tissues on Outcomes of Anterior Cruciate Ligament Reconstruction at Follow-up Arthroscopy

BACKGROUND

Remnant-preserving anterior cruciate ligament reconstruction (ACLR) is sought to enhance vascularization and maturation of a graft and to produce positive clinical outcomes after reconstruction.

OBJECTIVE

The purpose of this study was to investigate an effect of remnant anterior cruciate ligament (ACL) tissues on outcomes of ACLR 1 year after reconstruction in younger populations.

DESIGN

Retrospective chart review.

SETTING

Inpatient orthopedic surgical and rehabilitation clinic.

SUBJECTS

The subjects were 644 patients who underwent primary ACLR.

INDEPENDENT VARIABLES

The independent variables were age, height, and body weight of the subjects, and the presence of remnant tissue.

MAIN OUTCOME MEASURES

The outcome measure was the number of subjects with secondary infra-articular injuries at a follow-up arthroscopy after ACLR. The odds ratio was calculated and compared between the remnant-preserving ACLR (ACLR-P) and remnant-resecting (ACLR-R) groups to investigate the effect of remnant tissues on postoperative outcomes.

RESULTS

A total of 416 cases met our inclusion criteria and were included in this study. There were 136 cases (49 males and 87 females) in the ACLR-P group with the mean age (±SD) of 17.86 ± 2.85 years. There were 280 cases (106 males and 174 females) in the ACLR-R group, and the mean age (±SD) was 18.13 ± 2.73 years. Of 136 cases in the ALCR-P group, 54 (39.7%) had abnormal arthroscopic findings that lead to a surgical intervention. Of 280 patients in the ACLR-R group, 128 (45.7%) had abnormal findings. Odds ratio was 0.78 [95% confidence interval (CI), 0.51-1.18; P = 0.24]. Four cases in the ACLR-P group and 8 in the ACLR-R group were diagnosed with ACL retear during follow-up arthroscopy. Odds ratio was 1.03 (95% CI, 0.30-3.48; P = 0.96).

CONCLUSIONS

The presence of ACL remnant tissues did not have a significant effect on outcomes 1 year after reconstruction. However, there was a trend that lower percentage of patients with remnant-preserving ALCR had abnormal arthroscopic findings that lead to a surgical treatment at follow-up arthroscopy 1 year after initial reconstruction. The presence of remnant tissues did not have a significant effect on retear rate.

Visual Perturbation to Enhance Return to Sport Rehabilitation after Anterior Cruciate Ligament Injury: A Clinical Commentary

Anterior cruciate ligament (ACL) tears are common traumatic knee injuries causing joint instability, quadriceps muscle weakness and impaired motor coordination. The neuromuscular consequences of injury are not limited to the joint and surrounding musculature, but may modulate central nervous system reorganization. Neuroimaging data suggest patients with ACL injuries may require greater levels of visual-motor and neurocognitive processing activity to sustain lower limb control relative to healthy matched counterparts. Therapy currently fails to adequately address these nuanced consequences of ACL injury, which likely contributes to impaired neuromuscular control when visually or cognitively challenged and high rates of re-injury. This gap in rehabilitation may be filled by visual perturbation training, which may reweight sensory neural processing toward proprioception and reduce the dependency on vision to perform lower extremity motor tasks and/or increase visuomotor processing efficiency. This clinical commentary details a novel approach to supplement the current standard of care for ACL injury by incorporating stroboscopic glasses with key motor learning principles customized to target visual and cognitive dependence for motor control after ACL injury.

LEVEL OF EVIDENCE

5.

Hop Performance After Return to Sport in Anterior Cruciate Ligament-Reconstructed Gaelic Football and Hurling Athletes

PURPOSE

Anterior cruciate ligament (ACL) injuries are among the most severe injuries in the Gaelic Athletic Association. Hop tests measure functional performance after ACL reconstruction as they replicate the key requirements for a match situation. However, research examining functional recovery of ACL-reconstructed Gaelic athletes is lacking. The objective of this study is to determine if athletes restore normal hop symmetry after ACL reconstruction and to examine if bilateral deficiencies persist in hop performance following return to sport.

METHODS

A cross-sectional design was used to evaluate hop performance of 30 ACL-reconstructed Gaelic athletes who had returned to competition and 30 uninjured controls in a battery of hop tests including a single, 6-m, triple, and triple-crossover hop test.

RESULTS

In each test, the mean symmetry score of the ACL reconstruction group was above the cutoff for normal performance of 90% adopted by this study (98%, 99%, 97%, and 99% for the single, 6-m, triple, and triple-crossover hop, respectively). No significant differences in absolute hop scores emerged between involved and control limbs, with the exception of the single-hop test where healthy dominant limbs hopped significantly further than ACL-reconstructed dominant limbs (P = .02). No significant deficits were identified on the noninvolved side.

CONCLUSIONS

The majority of ACL-reconstructed Gaelic athletes demonstrate normal levels of hop symmetry after returning to competition. Suboptimal hop performance can persist on the involved side compared with control limbs. Targeted rehabilitation may be warranted after returning to competition to restore performance to levels of healthy uninjured athletes.

The effects of proprioceptive training on anterior cruciate ligament reconstruction rehabilitation: A systematic review and meta-analysis

OBJECTIVE

To determine the effectiveness of proprioceptive training on knee function and proprioception following anterior cruciate ligament reconstruction.

DATA SOURCES

PubMed, EMBASE, The Cochrane Library, Ovid, EBMSCO-host, ScienceDirect, CNKI, VIP, WanFang Data and CBM were searched until 2nd October 2020.

REVIEW METHODS

Trials with proprioceptive training for patients with anterior cruciate ligament reconstruction were included. Study screening, data extraction, risk of bias and quality assessments were performed independently by two researchers. We performed a stratified analysis based on the quality of the study. Sensitivity analyses were performed if the heterogeneity was high.

RESULTS

Seventeen trials with 878 participants were included, and 12/17 with low quality. After stratified analysis, the pooled effect of high-quality studies showed significant improvement for proprioceptive training group in range of motion (P < 0.05, I² = 0%), but no differences in Cincinnati knee rating system score (P > 0.05, I² = 83%), hop test (P>0.05, I² = 0%) and proprioception (P = 0.17, I² = 77%) compared to conventional training group; while the pooled effect of low-quality studies showed significant differences in knee functional improvement (P < 0.00001, I² = 69%), but no difference in proprioception (P > 0.05, I² = 84%) between two groups. The pooled effect of all studies showed a significant benefit in both function and proprioception.

CONCLUSION

The effects of proprioceptive training on knee functional and proprioceptive improvement after anterior cruciate ligament reconstruction is mixed. It is more likely that proprioceptive training in high-quality studies has few detectable effects and that low-quality studies show an effect because of an unconscious bias. A large well designed high-quality study needs to be undertaken in the future.

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

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

The Effect of Proprioceptive Training on Directional Dynamic Stabilization

OBJECTIVES

Significant loss of playing time and the impact of treatment costs due to lower limb injury in football demonstrates a need for improved protocols for injury risk reduction. The aim of the present study is to assess the effect of a proprioceptive training program on the lower limb dynamic stability of elite footballers.

METHODS

A total of 16 elite premier league footballers were randomly allocated by matched pair design to a 8-week proprioception training group (group A, n = 8) or nontraining group (group B, n = 8), to determine the effect of this training over a 16-week period. Group A completed 8 weeks of bilateral proprioceptive training, 5 times per week for 10 minutes. The Biodex Stability System measures of overall stability index, anterior-posterior (A-P), and medial-lateral stability (M-L) at levels 8-6-4-1 were taken for both groups at baseline, 4, 8, and 16 weeks. Main effects of time, level of stability, and direction of stability were determined, with comparisons of effect made between the 2 groups.

RESULTS

The training group displayed significant differences for multidirectional stability at week 8 (P ≤ .05). The A-P stability within the training group displayed significant differences between baseline measures and 16 weeks (P > .05), with significant increases in scores displayed for M-L and A-P stability between weeks 8 and 16 (P ≤ .05), representing a detraining effect. No significant differences were detected at any time point for the nontraining group (P > .05).

CONCLUSIONS

Proprioceptive training over 8 weeks has a positive effect on all directions of stability. Greater declines in A-P stability were evident at 16 weeks when compared with M-L and overall stability index. Consideration must be given to the increased stability scores presented pretesting for A-P when compared with M-L. Findings of this work present implications for training design.

Anterior cruciate ligament reconstruction using an anterior cruciate ligament stump

Introduction

Anterior cruciate ligament (ACL) injury always leads to knee pain and dysfunction for which surgical reconstruction is recommended, with good clinical results, but decreased postoperative proprioception also tends to occur. ACL stump (ACLS)-retaining ACL reconstruction and non-ACLS-retaining ACL reconstruction are the two surgical options.

Aim

To investigate the efficacy of retaining the ACLS in allograft reconstruction.

Material and methods

Thirty patients were retrospectively assigned to group A, ACLS-retaining ACL reconstruction; and group B, non-ACLS-retaining ACL reconstruction, and their data were analyzed. The knee function (Lysholm score and Tegner motion score) and proprioceptive function of the two groups were assessed and compared by postoperative reconstruction angle.

Results

The 30 patients were followed up for a mean 20 months. The mean Lysholm score in group A increased from 55.7 ±11.6 points preoperatively to 95.2 ±5.7 points postoperatively; that in group B increased from 56.7 ±11.3 points preoperatively to 94.6 ±7.2 points postoperatively. The mean Tegner motion score in group A was increased from 2.4 ±0.7 points preoperatively to 6.0 ±0.7 points postoperatively; that in group B increased from 2.73 ±0.96 points preoperatively to 6.24 ±0.48 points postoperatively; the postoperative scores did not differ significantly between the two groups. The proprioception was better in group A than in group B at 3, 6, and 12 months postoperatively (p < 0.05).

Conclusions

ACLS-retaining ACL reconstruction has good efficacy and the retained ACLS can benefit postoperative proprioception recovery at an early stage.

Gait speed is more challenging than cognitive load on the stride-to-stride variability in individuals with anterior cruciate ligament deficiency

BACKGROUND

Several investigations have studied gait variability of individuals with anterior cruciate ligament (ACL) deficiency; however, the effect of dual-tasking on the gait variability of these individuals remained unclear. The aim of the present study was to determine the effect of gait speed and dual-tasking on knee flexion-extension variability in subjects with and without ACL deficiency.

METHODS

The knee flexion-extension Lyapunov exponent (LyE) was measured in 22 ACL-deficient (Mean±SD) (25.95 ± 4.69 years) and 22 healthy subjects (24.18 ± 3.32 years). They walked at three levels of gait speed in isolation or concurrently with a cognitive task.

RESULTS

Repeated-measure analyses of variance (ANOVAs) demonstrated that the interaction of group by gait speed was statistically significant. As the gait speed increased from low to high, the knee flexion-extension LyE significantly decreased for the subjects with ACL deficiency (effect size: 0.57, P = 0.01). The interaction of group by cognitive load was not statistically significant (P = 0.07). In addition, the ACL-deficient subjects had statistically slower reaction times than healthy subjects during the dual-task compared with the single-task condition.

CONCLUSIONS

The ACL-deficient and healthy individuals had a tendency to maintain safe gait. It seems that the ACL-deficient subjects sacrificed the cognitive task more than the healthy individuals to pay more attention toward gait. Additionally, it seems that the gait speed was more challenging than cognitive load on the stride-to-stride variability in the individuals with ACL deficiency.

Effect of stochastic resonance on proprioception and kinesthesia in anterior cruciate ligament reconstructed patients

Low amplitude mechanical noise vibration has been shown to improve somatosensory acuity in various clinical groups with comparable deficiencies through a phenomenon known as Stochastic Resonance (SR). This technology showed promising outcomes in improving somatosensory acuity in other clinical patients (e.g., Parkinson's disease and osteoarthritis). Some degree of chronic somatosensory deficiency in the knee has been reported following anterior cruciate ligament (ACL) reconstruction surgery. In this study, the effect of the SR phenomenon on improving knee somatosensory acuity (proprioception and kinesthesia) in female ACL reconstructed (ACLR) participants (n = 19) was tested at three months post-surgery, and the results were compared to healthy controls (n = 28). Proprioception was quantified by the measure of joint position sense (JPS) and kinesthesia with the threshold to detection of passive movement (TDPM). The results based on the statistical analysis demonstrated an overall difference between the somatosensory acuity in the ACLR limb compared to healthy controls (p = 0.007). A larger TDPM was observed in the ACLR limb compared to the healthy controls (p = 0.002). However, the JPS between the ACLR and healthy limbs were not statistically significantly different (p = 0.365). SR significantly improved JPS (p = 0.006) while the effect was more pronounced in the ACLR cohort. The effect on the TDPM did not reach statistical significance (p = 0.681) in either group. In conclusion, deficient kinesthesia in the ACLR limb was observed at three months post-surgery. Also, the positive effects of SR on somatosensory acuity in the ACL reconstructed group warrant further investigation into the use of this phenomenon to improve proprioception in ACLR and healthy groups.

Neuroplastic changes in anterior cruciate ligament reconstruction patients from neuromechanical decoupling

The purpose of this study was to identify how the brain simultaneously perceives proprioceptive input during joint loading in anterior cruciate ligament reconstruction (ACLR) patients, when compared to healthy controls. Seventeen ACLR patients (ACLR) and seventeen controls (CONT) were tested for the somatosensory cortical activation using electroencephalography (EEG) while measuring knee laxity using a knee arthrometer. The relationship between cortical activation and joint laxity within group was also examined. The ACLR patients had increased cortical activation (36.4% ± 11.5%) in the somatosensory cortex during early loading (ERD1) to the injured limb compared to the CONT's matched limb (25.3% ± 13.2%, P = 0.013) as well as compared to the noninjured limb (25.1% ± 14.2%, P = 0.001). Higher somatosensory cortical activity during midloading (ERD2) to the ACLR knee positively correlated with knee laxity (mm) during early loading (LAX1, r = 0.530), midloading (LAX2, r = 0.506), total anterior loading (LAXA, r = 0.543), and total antero-posterior loading (LAXT, r = 0.501), while the noninjured limb revealed negative correlations between ERD1 and LAXA (r = -0.534) as well as between ERD2 and LAX2 (r = -0.565). ACLR patients demonstrate greater brain activation during joint loading in the injured knees when compared to healthy controls' matched knees as well as contralateral healthy knees, while the CONT group shows similar brain activation patterns during joint loading between limbs. These different neural activation strategies may indicate neuromechanical decoupling following an ACL reconstruction and evidence of altered sensorimotor perception and control of the knee (neuroplasticity), which may be critical to address after surgery for optimal neuromuscular control and patients' outcomes.

Coordination stability between the legs is reduced after anterior cruciate ligament reconstruction

BACKGROUND

The study was designed to examine coordination differences in walking between individuals with an anterior cruciate ligament reconstruction compared with healthy matched controls. Predictions from the extended Haken, Kelso, and Bunz coupled oscillator model were tested in these populations.

METHODS

Seventeen persons with anterior cruciate ligament reconstruction and 17 matched controls participated in the study. Sagittal plane angular knee displacement was recorded using electrogoniometers over the lateral right and left knee joints while participants walked at five walking speeds overground. Coordination pattern and stability between the knees were quantified by mean and standard deviation of relative phase, respectively.

FINDINGS

Mean relative phase was not influenced by walking speed or group. For both groups, coordination stability was maximal when individual's walked at their preferred gait speed. However, the anterior cruciate ligament reconstruction group demonstrated reduced coordination stability compared with healthy controls across the five speeds. Multiple regression analyses found that people with anterior cruciate ligament reconstruction who deviated more from antiphase coordination had decreased coordination stability.

INTERPRETATION

Anterior cruciate ligament reconstruction results in decreased coordination stability, indicative of reduced coupling strength between the legs. This change in gait coordination, which has not previously been found in the literature, may contribute to the increased rate of re-injury and degeneration in individuals who have had this reconstructive surgery. Application of a motor control model enhances our understanding of the influence of an injury on coordination during gait.

Neurophysiological correlates of motor planning and movement initiation in ACL-reconstructed individuals: a case-control study

INTRODUCTION

Current evidence suggests that the loss of mechanoreceptors after anterior cruciate ligament (ACL) tears might be compensated by increased cortical motor planning. This occupation of cerebral resources may limit the potential to quickly adapt movements to unforeseen external stimuli in the athletic environment. To date, studies investigating such neural alterations during movement focused on simple, anticipated tasks with low ecological validity. This trial, therefore, aims to investigate the cortical and biomechanical processes associated with more sport-related and injury-related movements in ACL-reconstructed individuals.

METHODS AND ANALYSIS

ACL-reconstructed participants and uninjured controls will perform repetitive countermovement jumps with single leg landings. Two different conditions are to be completed: anticipated (n=35) versus unanticipated (n=35) successful landings. Under the anticipated condition, participants receive the visual information depicting the requested landing leg prior to the jump. In the unanticipated condition, this information will be provided only about 400 msec prior to landing. Neural correlates of motor planning will be measured using electroencephalography. In detail, movement-related cortical potentials, frequency spectral power and functional connectivity will be assessed. Biomechanical landing quality will be captured via a capacitive force plate. Calculated parameters encompass time to stabilisation, vertical peak ground reaction force, and centre of pressure path length. Potential systematic differences between ACL-reconstructed individuals and controls will be identified in dependence of jumping condition (anticipated/ unanticipated, injured/uninjured leg and controls) by using interference statistics. Potential associations between the cortical and biomechanical measures will be calculated by means of correlation analysis. In case of statistical significance (α<0.05.) further confounders (cofactors) will be considered.

ETHICS AND DISSEMINATION

The independent Ethics Committee of the University of Frankfurt (Faculty of Psychology and Sports Sciences) approved the study. Publications in peer-reviewed journals are planned. The findings will be presented at scientific conferences.

TRIAL STATUS

At the time of submission of this manuscript, recruitment is ongoing.

TRIAL REGISTRATION NUMBER

NCT03336060; Pre-results.

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.

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.

Proprioception and Knee Arthroplasty: A Literature Review

Proprioceptive mechanoreceptors provide neural feedback for position in space and are critical for three-dimensional interaction. Proprioception is decreased with osteoarthritis of the knees, which leads to increased risk of falling. As the prevalence of osteoarthritis increases so does the need for total knee arthroplasty (TKA), and knowing the effect of TKA on proprioception is essential. This article reviews the literature regarding proprioception and its relationship to balance, aging, osteoarthritis, and the effect of TKA on proprioception. Knee arthroplasty involving retention of the cruciate ligaments is also reviewed, as well the evidence of proprioception in the posterior cruciate ligament after TKA.

PROPRIOCEPTION, BODY BALANCE AND FUNCTIONALITY IN INDIVIDUALS WITH ACL RECONSTRUCTION

OBJECTIVE

: To evaluate and compare proprioception, body balance and knee functionality of individuals with or without unilateral anterior cruciate ligament (ACL) reconstruction.

METHODS

: Forty individuals were divided in two groups: Experimental group, 20 individuals with ACL reconstruction at six months postoperative, and control group, 20 individuals with no history of lower limb pathologies. In the experimental group, we assessed lower limbs with reconstructed ACL and contralateral limb; in the control group the dominant and the non-dominant lower limbs were assessed. All subjects were submitted to joint position sense test to evaluate proprioception, postural control measure in single-limb, and step up and down (SUD) test for functional assessment.

RESULTS

: There were no deficits in proprioception and postural control. In the SUD test, a 5% decrease in lift up force was found in reconstructed ACL lower limbs, however, a statistically not significant difference. The impact and step down force during the course of test were 30% greater in anatomic ACL than in control lower limbs.

CONCLUSION

: The individuals with ACL reconstruction at six months postoperative did not show changes in proprioception and postural control, but showed motor control changes, influencing knee functionality. Level of Evidence IV, Prognostic Studies.

Body balance control deficiencies following ACL reconstruction combined with medial meniscus suture. A preliminary report

INTRODUCTION

Proprioception makes a critical contribution to body balance. The objective of this study was to evaluate static postural control after anterior cruciate ligament (ACL) reconstruction combined with medial meniscus (MM) suture, comparatively to healthy controls.

HYPOTHESIS

Body balance is adversely affected 2 months after ACL reconstruction combined with MM suture.

PATIENTS AND METHODS

Fifteen patients (12 males and 3 females) aged 20 to 35 years (mean, 26.4 ± 6.0 years) who underwent ACL reconstruction with MM suture were compared to 20 healthy, physically active controls (16 females and 4 males) aged 19 to 23 years (mean, 21.1 ± 1.8 years), most of whom were physiotherapy students. Mean age was not significantly different between the patients and controls. A balance platform was used to estimate static postural control parameters. Each participant performed four tests, two in normal bipedal stance and two in tandem stance; in each stance, one test was done with the eyes open and the other with the eyes closed. We analysed global scores on a standardised 100-point scale and mean centre of pressure (COP) displacement velocity in the sagittal and frontal planes.

RESULTS

Body balance was impaired 2 months after ACL reconstruction with MM suture. Thus, the patients had lower global scores and higher mean COP velocities in both the coronal and sagittal planes.

CONCLUSIONS

Proprioception is impaired after ACL reconstruction with MM suture. Lack of visual control significantly decreases the ability to maintain balance. A balance platform is a useful diagnostic tool for patients with ACL reconstruction and MM suture.

LEVEL OF EVIDENCE

Level II.

The Variants Within the COL5A1 Gene are Associated with Reduced Risk of Anterior Cruciate Ligament Injury in Skiers

The purpose of this study was to examine the association of the BstUI RFLP C/T (rs 12722) and DpnII RFLP C/T (rs 13946) COL5A1 polymorphisms, individually and as haplotypes, with anterior cruciate ligament ruptures in recreational skiers. Subjects were 138 male recreational skiers with surgically diagnosed primary anterior cruciate ligament ruptures. The control group consisted of 183 apparently healthy male recreational skiers, who were without any self-reported history of ligament or tendon injury. DNA was extracted from buccal cells donated by the subjects and genotyping was carried out using real-time PCR. The genotype distributions for both polymorphisms met Hardy-Weinberg expectations in both groups. There were no significant differences in genotype distribution of allele frequencies of COL5A1 BstUI RFLP C/T and COL5A1 DpnII RFLP C/T polymorphisms between the ACL rupture and control groups. The T-T (BstUI RFLP T, DpnII RFLP T) haplotype was the most common (55.6%). The haplotype T-C was not present in any of the subjects. There was an underrepresentation tendency of the C-T haplotype in the study group compared to controls under recessive mode of inheritance. Higher frequency of the COL5A1 BstUI RFLP C/T and COL5A1DpnII RFLP C/T polymorphisms haplotype is associated with reduced risk of anterior cruciate ligament injury in a group of apparently healthy male recreational skiers.

The role of the RNFA in anterior cruciate ligament graft preparation

Anterior cruciate ligament (ACL) reconstruction is one of the most commonly performed orthopedic procedures in the United States. Repair of the ACL often requires the use of autografts or allografts, and the RN first assistant (RNFA) often is the team member responsible for preparing the graft. Common grafts used in ACL repair include bone-patellar tendon-bone, hamstring, Achilles tendon, quadriceps tendon, and tibialis anterior tendon. The RNFA must be competent in preparing all of these grafts and in understanding the advantages and disadvantages of using each graft, such as the reasons for graft choice, and must ensure that all graft-related supplies and equipment are available and ready for use. The ability to prepare all graft types expands treatment options, reduces surgical time, and enhances the role of the RNFA.

Improved gold chloride staining method for anatomical analysis of sensory nerve endings in the shoulder capsule and labrum as examples of loose and dense fibrous tissues

Consistency in gold chloride staining is essential for anatomical analysis of sensory nerve endings. The gold chloride stain for this purpose has been modified by many investigators, but often yields inconsistent staining, which makes it difficult to differentiate structures and to determine nerve ending distribution in large tissue samples. We introduce additional steps and major changes to the modified Gairns' protocol. We controlled the temperature and mixing rate during tissue staining to achieve consistent staining and complete solution penetration. We subjected samples to sucrose dehydration to improve cutting efficiency. We then exposed samples to a solution containing lemon juice, formic acid and paraformaldehyde to produce optimal tissue transparency with minimal tissue deformity. We extended the time for gold chloride impregnation 1.5 fold. Gold chloride was reduced in the labrum using 25% formic acid in water for 18 h and in the capsule using 25% formic acid in citrate phosphate buffer for 2 h. Citrate binds gold nanoparticles, which minimizes aggregation in the tissue. We stored samples in fresh ultrapure water at 4° C to slow reduction and to maintain color contrast in the tissue. Tissue samples were embedded in Tissue Tek and sectioned at 80 and 100 μm instead of using glycerin and teasing the tissue apart as in Gairns' modified gold chloride method. We attached sections directly to gelatin subbed slides after sectioning with a cryostat. The slides then were processed and coverslipped with Permount. Staining consistency was demonstrated throughout the tissue sections and neural structures were clearly identifiable.

Does knee joint proprioception alter following medial patellofemoral ligament reconstruction?

BACKGROUND

This study firstly aimed to determine whether proprioception deficits, as measured by joint position sense (JPS), occur in people following recurrent patellar dislocations. Secondly, to determine whether JPS changes following medial patellofemoral ligament reconstruction (MPFL) reconstruction for patellar instability.

METHODS

Thirty people following recurrent patellar dislocation were recruited. Pre-operative JPS was assessed using the passive angle reproduction test. Through this, an assessor moved a participant's limb to a target position. This was returned to neutral, before finally moving the limb again, whilst requiring the participant to indicate when they thought the target angle was reached. The actual angular error (AAE) was calculated as the difference between the perceived angle and target angle. Clinical outcomes included the Kujala Patellofemoral Disorder Score, the International Knee Documentation Committee (IKDC) form, pain, knee motion, extensor muscle strength and frequency of patellar dislocation. Outcomes were assessed pre-operative, 6 weeks, 3 and 12 months.

RESULTS

Mean AAE was 2.2° (inner range) to 3.9° (mid-range); this was not clinically significant. There was no statistically significant difference between the baseline-and-6 week, 6 week-and-3 month or baseline-and-12 month AAE measures (p=0.38 to 1.00). There was a statistically significant improvement in functional outcomes as measured by the Kujala score, IKDC form, reduced pain and increased extension strength from baseline to 12 months (p<0.01).

CONCLUSIONS

Following recurrent patellar dislocation, patients exhibit minimal deficits in JPS. Whilst MPFL reconstruction significantly improved clinical and functional outcomes for this population, this operation did not significantly alter JPS during the first post-operative year.

Anterior-Posterior Instability of the Knee Following ACL Reconstruction with Bone-Patellar Tendon-Bone Ligament in Comparison with Four-Strand Hamstrings Autograft

Purpose. To evaluate anterior-posterior knee laxity using two different autografts. Material-Methods. 40 patients, (34 males and 6 women), 17-54 years old (mean: 31), were included in the present study. Group A (4SHS = 20) underwent reconstruction using four-strand hamstrings, and group B (BPBT = 20) underwent reconstruction using bone-patellar tendon-bone autograft. Using the KT-1000 arthrometer, knee instability was calculated in both knees of all patients preoperatively and 3, 6, and 12 months after surgery at the ACL-operated knee. The contralateral healthy knee was used as an internal control group. Results. Anterior-posterior instability using the KT1000 Arthrometer was found to be increased after ACL insufficiency. The recorded laxity improved after arthroscopic ACL reconstruction in both groups. However, statistically significant greater values were detected in the bone-patellar tendon-bone group, which revealed reduction of anteroposterior stability values to an extent, where no statistical significance with the normal values even after 3 months after surgery was observed. Conclusions. Anterior-Posterior instability of the knee improved significantly after arthroscopic ACL reconstruction. The bone-patellar tendon-bone graft provided an obvious greater stability.

The assessment of postural control and the influence of a secondary task in people with anterior cruciate ligament reconstructed knees using a Nintendo Wii Balance Board

BACKGROUND

Postural control impairments may persist following anterior cruciate ligament (ACL) reconstruction. The effect of a secondary task on postural control has, however, not been determined. The purpose of this case-control study was to compare postural control in patients following ACL reconstruction with healthy individuals with and without a secondary task.

PARTICIPANTS

45 patients (30 men and 15 women) participated at least 6 months following primary ACL reconstruction surgery. Participants were individually matched by age, gender and sports activity to healthy controls.

MATERIALS

Postural control was measured using a Nintendo Wii Balance Board and customised software during static single-leg stance and with the addition of a secondary task. The secondary task required participants to match the movement of an oscillating marker by adducting and abducting their arm.

MAIN OUTCOME MEASURES

Centre of pressure (CoP) path length in both medial-lateral and anterior-posterior directions, and CoP total path length.

RESULTS

When compared with the control group, the anterior-posterior path length significantly increased in the ACL reconstruction patients' operated (12.3%, p=0.02) and non-operated limbs (12.8%, p=0.02) for the single-task condition, and the non-operated limb (11.5%, p=0.006) for the secondary task condition. The addition of a secondary task significantly increased CoP path lengths in all measures (p<0.001), although the magnitude of the increase was similar in both the ACL reconstruction and control groups.

DISCUSSION

ACL reconstruction patients showed a reduced ability in both limbs to control the movement of the body in the anterior-posterior direction. The secondary task affected postural control by comparable amounts in patients after ACL reconstruction and healthy controls. Devices for the objective measurement of postural control, such as the one used in this study, may help clinicians to more accurately identify patients with deficits who may benefit from targeted neuromuscular training programs.

Partial ACL reconstruction with preservation of the posterolateral bundle

INTRODUCTION

Over the past decade, our understanding of the anterior cruciate ligament (ACL) has evolved considerably. Based on this knowledge, ACL reconstruction techniques have changed and selective reconstruction procedures have been developed for partial tears. Our hypothesis was that stability and function can be restored to the knee with selective bundle reconstruction of partial ACL tears and preservation of the residual fibers.

MATERIALS AND METHODS

This was a multicenter retrospective study of 168 partial reconstructions of the anteromedial (AM) bundle of the ACL with preservation of the posterolateral (PL) bundle. All patients underwent a clinical evaluation based on the objective and subjective IKDC scores and the Lysholm score after a mean follow-up of 26 months (12-59 months). Preoperative and postoperative instrumental measurement of knee laxity was performed by arthrometer and/or by (Telos(®)) stress radiography. Statistical analysis and comparison was performed between pre- and postoperative results.

RESULTS

The preoperative and postoperative subjective IKDC scores were 63.7 and 90.5 at the final follow-up respectively (P<0.001). The preoperative and postoperative Lysholm scores were 80 and 95.5 respectively (P<0.001). Preoperatively, most patients were classified C on the objective IKDC score. At the final follow-up 92% of the patients were classified A or B (P<0.001). Differential preoperative laxity was 5.5mm (range: 0-14 mm) and 1.1mm (range: 0-4mm) at the final follow-up (P<0.00001).

DISCUSSION AND CONCLUSION

Our study confirms that selective reconstruction of the AM bundle of the ACL with preservation of the PL bundle restores stability and function to the knee. Special attention should be paid to the size of the graft used to avoid excess tissue in the intercondylar notch.

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.

Differences among mechanoreceptors in healthy and injured anterior cruciate ligaments and their clinical importance

Mechanoreceptors in an intact Anterior Cruciate Ligament (ACL) contribute towards functional stability of the knee joint. Injury to the ACL not only causes mechanical instability, but also leads to a disturbance in the neuromuscular control of the injured knee due to loss or damage to mechanoreceptors. ACL reconstruction restores proprioceptive potential of the knee to some extent, but the results vary. Although the remnant ACL contains residual mechanoreceptors, the number and functionality of these receptors is dependent, to some extent, on the physical characteristics of the remnant and duration of injury. Remnants, especially that adherent to the PCL, may actually act as a possible source of reinnervation of the graft. These remnants are worth preserving during ACL reconstruction and can play an important role in restoration of proprioception of knee following ACL reconstruction.