Strength does not influence knee function in the ACL-deficient knee but is a correlate of knee function in the and ACL-reconstructed knee

Effectiveness of In-Home, Augmented Reality-Based Telerehabilitation After Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial

Background

New digital technology-based rehabilitation may be a viable option for patients after anterior cruciate ligament reconstruction (ACLR), with advantages such as easy access to treatment and learning as well as cost-effectiveness.

Purpose

To investigate the effects of an augmented reality (AR)-based, telerehabilitation system in patients after ACLR compared with a brochure-based rehabilitation program in terms of patient-reported outcomes and functional performance measures.

Study Design

Randomized controlled trial; Level of evidence, 2.

Methods

This was a multicenter, assessor-blinded study. Enrolled participants were allocated randomly to either the intervention group, who underwent AR-based telerehabilitation system, or to the control group, who underwent a brochure-based rehabilitation program with a self-log. Both groups performed the same postoperative rehabilitation exercise protocol. Subjective knee function was assessed using the International Knee Documentation Committee (IKDC) as the primary outcome; secondary outcomes were a numeric rating scale for pain, the EuroQol 5-Dimension 5-Level, isometric knee strength, range of motion, and the single-leg hop test. The intervention group also completed a satisfaction survey. Follow-up was conducted at 2, 6, 12, and 24 weeks postoperatively.

Results

A total of 28 patients were enrolled in each group; 1 patient in the control group was lost to follow-up. Patients in both groups demonstrated improvement on all outcomes over time. There were no significant between-group differences in the IKDC score from baseline to 12 weeks postoperatively. The intervention group saw a greater increase in the relative isometric strength of the quadriceps on the involved limb at 6, 12, and 24 weeks postoperatively (P < .05 for all). No significant group differences were observed in the remaining secondary outcomes.

Conclusion

Study findings indicated that patients who underwent AR-based telerehabilitation in the early rehabilitation phase after ACLR demonstrated similar improvements as those who followed a brochure-based rehabilitation program and had a quicker recovery of knee extensor strength.

Registration

NCT04513327 (ClinicalTrials.gov identifier).

Progressive submaximal effort hamstring muscle endurance is reduced after reconstruction of the anterior cruciate ligament

BACKGROUND

Endurance capability in the muscles controlling the knee is poorly understood post anterior cruciate ligament (ACL) reconstruction, despite many sporting activities requiring notable muscle endurance. The hamstring muscles, when active, provide important anatomical support to protect the reconstructed graft. In the absence of good hamstring endurance, fatigue may predispose individuals to re-injury.

OBJECTIVE

To assess whether ACL reconstruction (ACLR) with a hamstring graft leads to reduced hamstring endurance 9-13 months post-surgery.

STUDY DESIGN

A cross-sectional inter-limb comparison study was undertaken with participants 9-13 months after an ACLR with a hamstring graft, and a group of age, sex, and activity-matched controls. There were 22 participants in each group.

METHOD

Submaximal hamstring endurance was measured using a progressive fatigue test on an isokinetic dynamometer at a joint angular velocity of 120°/second. The dependant variable was the maximum number of repetitions performed. Statistical comparisons were made across injured, uninjured and control group limbs.

RESULTS

There was a significant (p < 0.05) deficit in hamstring endurance observed between the injured leg (mean: 111 repetitions, SD 49) and uninjured leg (mean: 136 repetitions, SD 67) of the ACL group, but not between the uninjured and control group legs (mean: 124 repetitions, SD 50).

CONCLUSION

The 18% deficit in submaximal hamstring endurance across the ACL-reconstructed individual's limbs is indicative of a notable loss in muscle performance at 9-13 months post-surgery. These results provide initial evidence for supporting further research examining the inclusion of hamstring endurance training in ACL rehabilitation programmes post-surgery.

The optimal window for reconstruction of the anterior cruciate ligament (ACL) with respect to quadriceps atrophies lies within 21 to 100 days

PURPOSE

The study's objective was to determine the optimal window for anterior cruciate ligament (ACL) reconstruction with respect to quadriceps atrophies and clinical outcome.

METHODS

For this retrospective, comparative study, 115 patients aged under 35 were included, who received an ACL reconstruction between 2011 and 2016. They were divided into four groups, depending on the time to surgery, to determine the optimal window for reconstruction: (group 1: ≤21 d, group 2: <21d-56d≥, group 3: >56d-100d≥, group 4: >100d). Follow-up was performed one month postoperatively, after a mean of 4.9 (±5.3) months, and after a mean of 3.5 (±1.4) years. Primary endpoints included quadriceps muscle status, range of motion (ROM), pain, swelling, the International Knee Documentation Committee Subjective Knee Form (IKDC), the Lysholm-Score, the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the Tegner-Activity-Scale (TAS).

RESULTS

Significantly more quadriceps atrophies were observed in group 1 and group 4, representing reconstructions earlier than 21 and later than 100 days (29% and 41% vs. 9%; p = 0.032). The measurements of knee extension (p = 0.082) and ROM (p = 0.123) were comparable in all groups. Group 1 showed the least pain (0% vs. 15%; p = 0.285) and swelling (0% vs. 23%; p = 0.077) compared to all other groups one month postoperatively. A comparison of postoperative clinical scores revealed no significant differences, with group 1 exhibiting the lowest TAS levels.

CONCLUSION

In patients who underwent ACL reconstruction within three weeks or after more than 100 days, a significantly higher incidence of quadriceps atrophy was observed, possibly attributable to the initial inflammatory phase or the delayed reconstruction affecting quadriceps function. However, this impairment may not be observable in elite athletes who undergo reconstruction within hours of the injury.

Post-Operative Modified All-Inside ACL Reconstruction Technique's Clinical Outcomes and Isokinetic Strength Assessments

BACKGROUND AND OBJECTIVE

Anterior cruciate ligament (ACL) injuries are very common among the athletic population. ACL reconstruction (ACLR) performed because of these injuries is one of the procedures performed by orthopedic surgeons using different grafting methods. This study aims to compare the data related to post-operative 6-month isokinetic strength values, strength-related asymmetry rates, time parameters, and joint angle in athletes who underwent ACLR with the Modified All-inside (4ST) technique, on both the healthy knee (HK) and the ACLR-applied sides.

MATERIALS AND METHODS

A total of 20 athletes from various sports on whom the 4ST ACLR technique had been applied by the same surgeon were evaluated retrospectively. Lysholm, Tegner, and International Knee Documentation Committee (IKDC) scores of the patients were obtained pre-operative and at 6 months post-operative. Isokinetic knee extension (Ex) and flexion (Flx) strengths on the HK and ACLR sides of the patients were evaluated with a series of four different angular velocities (60, 180, 240, and 300°/s). In addition to peak torque (PT) and hamstring/quadriceps ratio (H/Q) parameters, the findings were also evaluated with additional parameters such as joint angle at peak torque (JAPT), time to peak torque (TPT), reciprocal delay (RD), and endurance ratio (ER).

RESULTS

There was a significant improvement in the mean Lysholm, Tegner, and IKDC scores after surgery compared with pre-operative levels (p < 0.05). As for PT values, there were significant differences in favor of the HK in the 60, 180, and 300°/s Ex phases (p < 0.05). In terms of the H/Q and (hamstring/hamstring)/(quadriceps/quadriceps) (HH/QQ) ratios, there were significant differences at 300°/s (p < 0.05). In terms of JAPT, there were significant differences in the 300°/s Ex and 180°/s Flx phases (p < 0.05). In terms of TPT, there were significant differences in the 300°/s Ex phase (p < 0.05). In terms of RD and ER, no significant difference was observed between the HK and ACLR sides at any angular velocity.

CONCLUSIONS

Although differences were observed in PT values, particularly in the Ex phase, this did not cause a significant change in H/Q ratios. Similar results were observed for additional parameters such as JAPT, TPT, RD, and ER. The results show that this ACLR technique can be used in athletes in view of strength gain and a return to sports.

Anterior cruciate ligament reconstruction results in better patient reported outcomes but has no advantage for activities of daily living or the subsequent development of osteoarthritis. A systematic review and meta-analysis

BACKGROUND

Surgical reconstruction of ACL injuries is a common strategy but superiority over conservative treatment has not been established. The aim was to perform a systematic review and meta-analysis comparing outcomes between operative and non-operative treatment of ACL injuries.

METHODS

Systematic review of Medline, Embase, Scopus, and Google Scholar, including all level 1-3 studies from 2000 to 2021. Patient reported outcome scores and objective measures for knee stability were included. Risk of bias was assessed using the Cochrane Collaboration's tools. GRADE was used to assess the quality of the body of evidence. Heterogeneity was assessed using χ2 and I² statistics.

RESULTS

Twelve studies were included in the analysis. All studies had a high risk of bias and were of low quality. The pooled estimates for IKDC (p = 0.040) favored surgical treatment. There were significant differences for activities of daily living (p = 0.0001) in favor of conservative treatment. There were significant differences for knee stability (p = 0.016) in favor of surgical treatment. The risk of osteoarthritis was not significantly different between the two treatment modalities (p = 0.219). Patients undergoing surgery had a 57% higher risk of osteoarthritis.

CONCLUSION

ACL reconstruction results in a significantly more stable knee with superior clinical and functional outcomes. However, these advantages over conservative treatment were not observed for routine activities of daily living, and subjective patient perceived outcomes favor nonsurgical treatment. Surgical treatment did not reduce the risk of later developing osteoarthritis. Regardless, due to low study quality and high risk of bias, these findings must be interpreted with caution.

The time from injury to surgery is an important factor affecting the mechanoreceptors at stump of torn anterior cruciate ligament

INTRODUCTION

Restoration of proprioceptive function after anterior cruciate ligament (ACL) reconstruction is as important as mechanical stability. For this purpose, remnant of the torn ACL is the only source of nerve endings. Our aim in this study is to investigate the quantity of mechanoreceptors in the remnants ACL stumps in injured knees and to correlate that with the quantity in intact ACL in control cases.

MATERIALS AND METHODS

48 patients that underwent ACL reconstruction between January 2016 and December 2018 as study group and 20 knees of 10 fresh frozen cadavers that as control group included in the study. Remaining stumps from study group and native ACL from control group were collected and investigated with S100 immunostaining. The type and number of mechanoreceptors in standardized areas was determined. The correlation of number of mechanoreceptors and time to surgery after ACL rupture were evaluated.

RESULTS

The free nerve endings (FNE) and total number of mechanoreceptors were significantly lower in the study group as compared to the control group (p < 0.001 and p = 0.004, respectively). The number of Golgi-Mazzoni corpuscle decreased significantly with time (p = 0.041 CC: - 0.438).

CONCLUSION

The time from injury to surgery is an important factor affecting the mechanoreceptors at stump of torn ACL. The surgeon and patient should be aware of the fact that delay in surgery could lead to the loss of mechanoreceptors.

Measurement properties for muscle strength tests following anterior cruciate ligament and/or meniscus injury: What tests to use and where do we need to go? A systematic review with meta-analyses for the OPTIKNEE consensus

Objectives

Critically appraise and summarise the measurement properties of knee muscle strength tests after anterior cruciate ligament (ACL) and/or meniscus injury using the COnsensus-based Standards for the selection of health Measurement INstruments Risk of Bias checklist.

Design

Systematic review with meta-analyses. The modified Grading of Recommendations Assessment, Development and Evaluation-guided assessment of evidence quality.

Data sources

Medline, Embase, CINAHL and SPORTSDiscus searched from inception to 5 May 2022.

Eligibility criteria for selecting studies

Studies evaluating knee extensor or flexor strength test reliability, measurement error, validity, responsiveness or interpretability in individuals with ACL and/or meniscus injuries with a mean injury age of ≤30 years.

Results

Thirty-six studies were included involving 31 different muscle strength tests (mode and equipment) in individuals following an ACL injury and/or an isolated meniscus injury. Strength tests were assessed for reliability (n=8), measurement error (n=7), construct validity (n=27) and criterion validity (n=7). Isokinetic concentric extensor and flexor strength tests were the best rated with sufficient intrarater reliability (very low evidence quality) and construct validity (moderate evidence quality). Isotonic extensor and flexor strength tests showed sufficient criterion validity, while isometric extensor strength tests had insufficient construct and criterion validity (high evidence quality).

Conclusion

Knee extensor and flexor strength tests of individuals with ACL and/or meniscus injury lack evidence supporting their measurement properties. There is an urgent need for high-quality studies on these measurement properties. Until then, isokinetic concentric strength tests are most recommended, with isotonic strength tests a good alternative.

Traditional and Additional Isokinetic Knee Strength Assessments of Athletes; Post-Operative Results of Hamstring Autograft ACL Reconstruction

Background and Objectives: Anterior cruciate ligament (ACL) injuries are common injuries in athletes, and, accordingly, ACL reconstruction (ACLR) is one of the most common orthopedic surgical procedures performed on athletes. This study aims to compare the 6-month post-operative isokinetic knee strength evaluations of the semitendinous/gracilis (ST/G) ACLR technique performed on healthy (HK) and ACLR knees of athletes. Materials and Methods: A retrospective cohort of 29 athletes from various sports branches who underwent ST/G ACLR technique by the same surgeon were evaluated. The isokinetic knee extension (Ex) and flexion (Flx) strength of the patients on the HK and ACLR sides were evaluated with a series consisting of three different angular velocities (60, 180, and 240°/s). In addition to the traditional evaluations of peak torque (PT) and hamstring/quadriceps (H/Q) parameters, the findings were also evaluated with additional parameters such as the joint angle at peak torque (JAPT), time to peak torque (TPT), and reciprocal delay (RD). Results: There was a significant improvement in the mean Lysholm, Tegner, and IKDC scores after surgery compared with preoperative levels (p < 0.05). As for the isokinetic PT values, there were significant differences in favor of HK in the 60°/s Flx, 180°, and 240°/s Ex phases (p < 0.05). In addition, there was a significant difference in the 60° and 180°/s Flx phases in RD (p < 0.05). In H/Q ratio, TPT, and JAPT values, no significant difference was observed between HK and ACLR at all angular velocities. Conclusions: The findings showed that the ST/G 6-month post-operative isokinetic knee strength in athletes produced high results in HK, and, when evaluated in terms of returning to sports, the H/Q ratios on the ACLR side were sufficient to make the decision to return to sports. It was found that the ACLR side was slower than the HK side in the reciprocal transitions, particularly in the Flx phase. We believe that this results from the deformation of the hamstring muscle after reconstruction of the ST/G ACLR side.

Correlation among Knee Muscle Strength and Self-Reported Outcomes Score, Anterior Tibial Displacement, and Time Post-Injury in Non-Coper Anterior Cruciate Ligament Deficient Patients: A Cross-Sectional Study

Little attention has been paid to knee muscle strength after ACL rupture and its effect on prognostic outcomes and treatment decisions. We studied hamstrings (H) and quadriceps (Q) strength correlation with a patient-reported outcome measures score (International Knee Documentation Committee, IKDC), anterior tibial translation (ATT), and time post-injury in 194 anterior cruciate ligament deficient patients (ACLD) who required surgery after a failed rehabilitation program (non-copers). The correlation between knee muscle strength and ATT was also studied in 53 non-injured controls. ACLD patients showed decreased knee muscle strength of both the injured and non-injured limbs. The median (interquartile range) values of the H/Q ratio were 0.61 (0.52-0.81) for patients' injured side and 0.65 (0.57-0.8) for the non-injured side (p = 0.010). The median H/Q ratio for the controls was 0.52 (0.45-0.66) on both knees (p < 0.001, compared with the non-injured side of patients). The H/Q, ATT, and time post-injury were not significantly correlated with the IKDC score. ATT was significantly correlated with the H/Q of the injured and non-injured knees of patients, but not in the knees of the controls. Quadriceps strength and H/Q ratio were significantly correlated with ATT for both limbs of the patients. IKDC score correlated significantly with the quadriceps and hamstrings strengths of the injured limb but not with the H/Q ratio, ATT or time passed after injury.

Editorial Commentary: Fifty Is the New 30? Do Patients in Their 50s Deserve an Anterior Cruciate Ligament Reconstruction?

Evidence suggests that anterior cruciate ligament reconstruction in patients older than 50 years of age has similar outcomes when compared with younger patients. However, poorer results are associated with advanced degenerative intra-articular chondral changes. The caveat here is that these conclusions are mainly based on retrospective level IV case series. The question is whether functionally unstable patients 50 years and older, whether active or not, benefit from surgical reconstruction and the answer is clearly yes. It provides restoration of function and should be considered in active older patients with subjective instability who have not responded to nonoperative treatment.

Cross-cultural adaptation and measurement properties of the Brazilian-Portuguese version of the Cincinnati Knee Rating System

Purpose: To translate, culturally adapt, evaluate the measurement properties, and propose a new scoring system of the Cincinnati Knee Rating System for the Brazilian population.Materials and Methods: One hundred fifty people with anterior cruciate ligament injury completed Cincinnati Knee Rating System and Lysholm Knee Scoring Scale on three occasions: 1-week prior to surgery, 90-days after and 95-days after reconstruction. The measurement properties of the Brazilian-Portuguese Cincinnati Knee Rating System, internal consistency, construct validity, reproducibility, ceiling and floor effect and responsiveness, were tested.Results: Using the original scoring system (multiple scores), the internal consistency (Cronbach's α) varied between 0.54-0.79 (if item deleted = 0.07-0.73); the construct validity (Pearson's r) varied between 0.19-0.82 (related to Lysholm); the reliability (intraclass correlation coefficient) varied between 0.96-0.99; the standard error of measurement varied between 0.2-1.3 points; the minimum detectable change varied between 0.4-3.5 points; no ceiling or floor effect was detected, and responsiveness (effect size) varied between -0.3-2.7. Using the new proposed scoring system (single score), Cronbach's α was 0.78 (if item deleted = 0.65-0.71); the Pearson's r was 0.79 (related to Lysholm); the intraclass correlation coefficient was 0.99; the standard error of measurement was 0.5 points, the minimum detectable change was 1.3 points; no ceiling or floor effect was detected, and effect size was 1.4.Conclusions: The Brazilian-Portuguese Cincinnati Knee Rating System has adequate property measurement and can be used in a Brazilian population. The new proposed scoring system is appropriate.Implications for rehabilitationThe Brazilian-Portuguese Cincinnati Knee Rating System is a valid and reliable instrument which can identify consistent clinical changes over the time.The Brazilian-Portuguese Cincinnati Knee Rating System can be used to evaluate and to follow-up a Brazilian population with anterior cruciate ligament injuries and postoperative reconstruction.The new proposed score for Cincinnati Knee Rating System is appropriate and did not compromise the quality of the measurement properties.The new scoring system generates a unique score, creating a potentially simpler and faster clinical understanding of the patient's condition.

The hamstring/quadriceps ratio is an indicator of function in ACL-deficient, but not in ACL-reconstructed knees

PURPOSE

The purpose of this study was to investigate the isokinetic, eccentric and isometric hamstring/quadriceps (HQ) ratios in patients before and after ACL reconstruction (ACLR) using bone-patellar tendon grafts and to establish the relationships between HQ ratio and knee function.

METHODS

Forty-four patients (mean age of 26.6 years) underwent isokinetic testing of quadriceps and hamstring muscles before and after ACLR and HQ ratios were calculated. Lysholm, IKDC and Cincinnati Scores were used to assess function. Isokinetic concentric and eccentric peak torque (Nm/kg) was measured at three different speeds: 60, 120, and 180°/s. Isometric strength was tested at 30° and 60° of knee flexion.

RESULTS

For the isometric tests, the HQ ratio between the involved and non-involved limb was not different for the ACLD knee (p = 0.28) at 30° knee flexion, but significant at the 60° flexion angle (p = 0.02) and for the ACLR knees at 30° and 60° (p = 0.02). For the isokinetic tests, the ratio between involved and non-involved limb was significant for ACL-deficient knees at both 60 (p = 0.039) and 120°/s (p = 0.05). There were significant differences between limbs for all speeds in ACLR knees (p = 0.0003-0.01). For the eccentric tests, the HQ ratio between the involved and non-involved limbs was not significant for both the ACLD (p = 0.19) and ACLR knees (p = 0.29) at the speed of 60°/s. At 120 and 180°/s, there were significant differences between limbs for both the ACLD (p = 0.02) and ACLR knees (p = 0.003). Linear regression did not reveal significant relationships between Cincinnati, Lysholm, and IKDC scores and HQ ratios in the ACLD (R² = 0.35, p = 0.58; R² = 0.34, p = 0.63; R² = 0.38, p = 0.49). In contrast, there were significant correlations between the Lysholm and IKDC scores and HQ ratios in the ACLR knees (R² = 0.84, p = 0.002; R² = 0.86, p = 0.001).

CONCLUSIONS

The findings of this study suggest that the HQ ratio in ACLD patients was not a predictor, but an indicator of patient-perceived knee function following ACLR.

LEVEL OF EVIDENCE

Level IV, case series.

Quadriceps Function and Patient-Reported Outcomes After Anterior Cruciate Ligament Reconstruction in Patients With or Without Knee Osteoarthritis

CONTEXT

Relationships between quadriceps function and patient-reported outcomes after anterior cruciate ligament reconstruction (ACLR) are variable and may be confounded by including patients at widely different time points after surgery. Understanding these relationships during the clinically relevant phases of recovery may improve our knowledge of specific factors that influence clinical outcomes.

OBJECTIVE

To identify the relationships between quadriceps function and patient-reported outcomes in patients <2 years (early) and >2 years (late) after ACLR, including those with posttraumatic knee osteoarthritis.

DESIGN

Cross-sectional study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 72 patients after ACLR: early (n = 34, time from surgery = 9.0 ± 4.3 months), late (n = 30, time from surgery = 70.5 ± 41.6 months), or osteoarthritis (n = 8, time from surgery = 115.9 ± 110.0 months).

MAIN OUTCOME MEASURE(S)

The total Knee Injury and Osteoarthritis Outcome Score (KOOS) and Veterans RAND 12-Item Health Survey (VR-12) were used to quantify knee function and global health. Predictors of patient-reported outcomes were involved-limb and symmetry indices of quadriceps function (isokinetic strength [peak torque, total work, average power], maximum voluntary isometric contraction torque, fatigue index, central activation ratio, Hoffmann reflex, active motor threshold) and demographics (age, activity level, pain, kinesiophobia, time since surgery). Multiple linear regression analyses were used to predict KOOS and VR-12 scores in each group.

RESULTS

In the early patients, knee-extensor work, active motor threshold symmetry, pain, and activity level explained 67.8% of the variance in the KOOS score ( P < .001); knee-extensor work, activity level, and pain explained 53.0% of the variance in the VR-12 score ( P < .001). In the late patients, age and isokinetic torque symmetry explained 28.9% of the variance in the KOOS score ( P = .004). In the osteoarthritis patients, kinesiophobia and isokinetic torque explained 77.8% of the variance in the KOOS score ( P = .010); activity level explained 86.4% of the variance in the VR-12 score ( P = .001).

CONCLUSIONS

Factors of muscle function and demographics that explain patient-reported outcomes were different in patients early and late after ACLR and in those with knee osteoarthritis.