Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study

Telerehabilitation to Address the Rehabilitation Gap in Anterior Cruciate Ligament Care: Survey of Patients

BACKGROUND

Evidence shows that after anterior cruciate ligament (ACL) reconstruction, patients may have varied access to physical therapy. In particular, physical therapy input may end many months before patients reach full recovery. Telerehabilitation may provide an opportunity to address this rehabilitation gap and improve access to evidence-based rehabilitation alongside physical therapy at all stages of care.

OBJECTIVE

This study aims to understand the opinions of patients who have undergone ACL surgery and rehabilitation on the use of telerehabilitation as part of ACL care and define the population and explore their experiences and views on the acceptability of telerehabilitation after ACL reconstruction.

METHODS

This study was a cross-sectional, voluntary, web-based survey combining both closed and open questions. Ethical approval was obtained from the Yale School of Medicine Institutional Review Board. Participants were aged 16 years or older at the time of recruitment and had undergone ACL reconstruction within the past 5 years. A 26-item survey was developed using the Qualtrics survey platform. No items were mandatory. Responses were multiple choice, binary, and qualitative. The CHERRIES (Checklist for Reporting Results of Internet E-Surveys) was used to ensure the quality of reporting of surveys in the medical literature. Data were analyzed using Stata version 15. Qualitative data were analyzed using NVivo 11. The theoretical framework for this analysis is based on the Capability, Opportunity, and Motivation-Behavior model of behavior change.

RESULTS

A total of 100 participants opened the survey. All completers were unique. The participation and completion rates were each 96% (96/100). Patients reported their physical therapy care ended at an average of 6.4 months and that they felt fully recovered at an average of 13.2 months. Only 26% (25/96) of patients felt fully recovered at the end of physical therapy. Of these 96 patients, 54 (60%) were younger than 30 years, 71 (74%) were recreational athletes, 24 (24%) were competitive athletes, 72 (75%) had private insurance, 74 (77%) were not familiar at all with telerehabilitation, and 89% (85/96) felt capable. They preferred to use telerehabilitation at different stages of care. Reported benefits included resource saving, improved access to care, improved learning, and greater engagement. Concerns included incorrect performance of exercises or unmanaged pain being missed and less access to manual therapy, motivation, and opportunities to ask questions. Participants' priorities for a future telerehabilitation intervention included its use as an adjunct to physical therapy rather than a replacement, with content available for each stage of care, especially return to sports. Participants stressed that the intervention should be personalized to them and include measures of progress.

CONCLUSIONS

These findings helped understand and define the ACL reconstruction population. Participants found telerehabilitation acceptable in principle and highlighted the key user requirements and scope of future interventions.

Differences in Strength, Patient-Reported Outcomes, and Return-to-Play Rates Between Athletes With Primary Versus Revision ACL Reconstruction at 9 Months After Surgery

Background:

Patient-reported outcomes and return-to-play (RTP) rates are inferior after revision anterior cruciate ligament reconstruction (ACLR) compared with primary ACLR. Physical properties such as maximal, explosive, and reactive strength influence reinjury and RTP rates after ACLR. No study has compared these outcomes between revision and primary ACLR.

Purpose:

To compare maximal, explosive, and reactive strength of the ACLR limb, as well as patient-reported outcomes and RTP rates between primary and revision ACLR at 9 months after surgery.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A comparative study was performed at 9 months after surgery for 344 male athletes who had undergone ACLR (298 primary, 46 revision). Maximal strength of the ACLR limb was measured by means of isokinetic dynamometry. Explosive strength was measured by use of single-leg countermovement jump height, and reactive strength was measured by single-leg drop jump. Patient-reported outcomes and responses to RTP questionnaires were recorded for both groups.

Results:

The primary ACLR group had higher scores than the revision ACLR group for single-leg countermovement jump height (P = .02) and single-leg drop jump reactive strength index (P = .01) on the ACLR limb. No significant difference was observed between groups on maximal strength of the quadriceps or hamstring, and no significant difference in limb symmetry index was observed between groups on any strength or jump test. The primary ACLR group demonstrated higher scores on the Marx Activity Rating Scale (P = .03) and the Anterior Cruciate Ligament–Return to Sport after Injury scale (P < .001). Athletes in the primary ACLR group were more likely to have returned to sport (P < .001).

Conclusion:

At 9 months after surgery, athletes who had undergone revision ACLR achieved maximal strength similar to that of athletes who had undergone primary ACLR. However, athletes who had revision ACLR demonstrated lower scores on explosive and reactive strength tests. Athletes who underwent revision ACLR had lower RTP rates at 9 months after surgery, potentially due to explosive and reactive strength deficits and lower perceived readiness for RTP.

Michigan Initiative for Anterior Cruciate Ligament Rehabilitation (MiACLR): A Protocol for a Randomized Clinical Trial

OBJECTIVE

Restoring quadriceps muscle strength following anterior cruciate ligament reconstruction (ACLR) may prevent the posttraumatic osteoarthritis that affects over 50% of knees with ACLR. However, a fundamental gap exists in our understanding of how to maximize muscle strength through rehabilitation. Neurological deficits and muscle atrophy are 2 of the leading mechanisms of muscle weakness after ACLR. High-intensity neuromuscular electrical stimulation (NMES) and eccentric exercise (ECC) have been shown to independently target these mechanisms. If delivered in succession, NMES and then ECC may be able to significantly improve strength recovery. The objectives of this study were to evaluate the ability of NMES combined with ECC to restore quadriceps strength and biomechanical symmetry and maintain cartilage health at 9 and 18 months after ACLR.

METHODS

This study is a randomized, double-blind, placebo-controlled, single-center clinical trial conducted at the University of Michigan. A total of 112 participants between the ages of 14 and 45 years and with an anterior cruciate ligament rupture will be included. Participants will be randomly assigned 1:1 to NMES combined with ECC or NMES placebo combined with ECC placebo. NMES or NMES placebo will be delivered 2 times per week for 8 weeks beginning 10 to 14 days postoperatively and will be directly followed by 8 weeks of ECC or ECC placebo delivered 2 times per week. The co-primary endpoints are change from baseline to 9 months and change from baseline to 18 months after ACLR in isokinetic quadriceps strength symmetry. Secondary outcome measures include isometric quadriceps strength, quadriceps activation, quadriceps muscle morphology (cross-sectional area), knee biomechanics (sagittal plane knee angles and moments), indexes of patient-reported function, and cartilage health (T1ρ and T2 relaxation time mapping on magnetic resonance imaging).

IMPACT

The findings from this study might identify an intervention capable of targeting the lingering quadriceps weakness after ACLR and in turn prevent deterioration in cartilage health after ACLR, thereby potentially improving function in this patient population.

Limiting the Risk of Osteoarthritis After Anterior Cruciate Ligament Injury: Are Health Care Providers Missing the Opportunity to Intervene?

OBJECTIVE

To understand what sports orthopedic surgeons (OS), primary care physicians (PCPs) with sports medicine training, and physical therapists (PTs) managing nonelite athletes with anterior cruciate ligament (ACL) injury tell their patients about their osteoarthritis (OA) risk.

METHODS

An electronic survey was distributed by the Canadian Academy of Sport and Exercise Medicine (PCPs, OS), the Sports and Orthopedic Divisions of the Canadian Physiotherapy Association (PTs), and to OS identified through the Royal College of Physicians and Surgeons and the Canadian Orthopaedic Association. The survey included 4 sections: demographics, factors discussed, timing of discussions, and discussion of risk factors and their management. Proportions or means with 95% confidence intervals were calculated.

RESULTS

A total of 501 health care professionals (HCPs) responded (98 PCPs, 263 PTs, and 140 OS). Of those responding, 70-77% of physicians reported always discussing OA risk, but only 35% of PTs did. All HCPs reported that patient activities perceived as detrimental to knee health, ACL reinjury, and simultaneous injury to other structures in the knee were most often the reason for discussing OA risk. OA risk was discussed at initial management post-injury (65-94%), with few discussing risk subsequently. Eighty percent of physicians and 99% of PTs indicated that PTs were suited to provide OA risk and management information.

CONCLUSION

HCPs routinely managing people with ACL injury do not consistently discuss OA risk post-injury with them. Educational strategies for HCPs are urgently needed to develop care pathways inclusive of support for OA risk management following ACL injury.

Single-Leg Squat After Anterior Cruciate Ligament Reconstruction: An Analysis of the Knee Valgus Angle at 6 and 12 Months

Background:

Deficits in neuromuscular control are common after anterior cruciate ligament (ACL) reconstruction and may be associated with further knee injury. The knee valgus angle during a single-leg squat (SLS) is one measure of neuromuscular performance.

Purpose:

To determine whether the knee valgus angle during SLS changes between 6 and 12 months after ACL reconstruction and to assess how the operative knee valgus angle compares with that of the contralateral side.

Study Design:

Case series; Level of evidence, 4.

Methods:

A cohort of 100 patients with uninjured contralateral knees were assessed at 6 and 12 months after primary hamstring autograft ACL reconstruction. Participants performed the SLS on each leg, and the knee valgus angle was measured via frame-by-frame video analysis at 30° of flexion and at each patient’s maximum knee flexion angle.

Results:

For the operative limb at 30° of flexion, a small but statistically significant reduction was noted in the valgus angle between 6 and 12 months (5.46° vs 4.44°; P = .002; effect size = 0.24). At 6 months, a slightly higher valgus angle was seen in the operative limb compared with the nonoperative limb (5.46° vs 4.29°; P = .008; effect size = 0.27). At maximum flexion, no difference was seen between limbs in the valgus angle at either 6 or 12 months, and no change was seen in the operative limb between 6 and 12 months. At 6 months and 30° of knee flexion, 13 patients had a valgus angle greater than 10°. This group also had a higher mean valgus angle in the contralateral limb compared with the contralateral limb in the other 87 patients (8.5° vs 3.65°; P < .001).

Conclusion:

During a controlled SLS, the knee valgus angle remained essentially constant, and minimal limb asymmetries were present over the 6- to 12-month postoperative period, a time when athletes typically increase their activity levels. Whether changes or asymmetries will be seen with more dynamically challenging tasks remains to be determined. When present, high valgus angles were commonly bilateral.

Association between Functional Performance and Return to Performance in High-Impact Sports after Lower Extremity Injury: A Systematic Review

After lower extremity injury, only half of the injured athletes return to their pre-injury sports level. Even though functional performance tests are often used to make return to sport decisions, it is unknown whether functional performance is associated with return to performance after such injuries. The aim of this systematic review was to identify, critically appraise, and analyze studies that investigated the association of functional performance tests with return to performance after lower extremity injuries in athletes participating in high-impact sports. MEDLINE, Embase, Web of Science, and CINAHL were systematically searched for relevant studies. Articles were independently screened by two authors and data were obtained from each included study using a data extraction form. Two authors independently scored methodological quality using the Quality In Prognosis Studies tool. A qualitative best evidence synthesis was conducted. Eight studies reported the association of functional performance with return to performance after lower extremity injuries, involving 1,246 athletes after anterior or posterior cruciate ligament reconstruction. No studies were found on the association of functional performance with return to performance for lower extremity injuries other than after anterior or posterior cruciate ligament reconstruction. All included studies had a high risk of bias. Two studies found significant but small associations for selected hop tests after anterior cruciate ligament reconstruction. Low evidence of association between functional performance and return to performance was present after anterior cruciate ligament reconstruction for the triple hop for distance, the 6-meter timed hop, the side hop in female athletes, and for the combination of the single and crossover hop for distance. In athletes after posterior cruciate ligament reconstruction, the vertical jump showed a significant but small association with return to performance. There is no high-quality evidence that functional performance is associated with return to performance after lower extremity injuries in athletes practicing high-impact sports. Low quality evidence suggests small associations after anterior and posterior cruciate ligament reconstruction. No evidence exists for lower extremity injuries other than after anterior or posterior cruciate ligament reconstruction. Therefore, research on functional performance associated with return to performance is recommended in high-quality prospective cohort studies including athletes with any type of lower extremity injury.

Examination of Corticospinal and Spinal Reflexive Excitability During the Course of Postoperative Rehabilitation After Anterior Cruciate Ligament Reconstruction

OBJECTIVE

To investigate corticospinal and spinal reflexive excitability and quadriceps strength in healthy athletes and athletes after anterior cruciate ligament reconstruction (ACLR) over the course of rehabilitation.

DESIGN

Prospective cohort study.

METHODS

Eighteen athletes with ACLR and 18 healthy athletes, matched by sex, age, and activity, were tested at (1) 2 weeks after surgery, (2) the "quiet knee" time point, defined as full range of motion and minimal effusion, and (3) return to running, defined as achieving a quadriceps index of 80% or greater. We measured (1) corticospinal excitability, using resting motor threshold (RMT) and motor-evoked potential amplitude at a stimulator intensity of 120% of RMT (MEP₁₂₀) to the vastus medialis, (2) spinal reflexive excitability, calculating the ratio of the maximal Hoffmann reflex to the maximal M-wave to the vastus medialis, and (3) isometric quadriceps strength.

RESULTS

The ACLR group had higher RMTs in the nonsurgical limb and higher MEP₁₂₀ in the surgical limb at all time points. The healthy-athlete group did not have interlimb differences. The RMT was positively associated with quadriceps strength 2 weeks after surgery; MEP₁₂₀ was associated with quadriceps strength at all time points.

CONCLUSION

Compared to healthy athletes, athletes after ACLR had altered corticospinal excitability that did not change from 2 weeks after surgery to the time of return to running. J Orthop Sports Phys Ther 2020;50(9):516-522. Epub 1 Aug 2020. doi:10.2519/jospt.2020.9329.

Current Perspectives of the Australian Knee Society on Rehabilitation and Return to Sport After Anterior Cruciate Ligament Reconstruction

CONTEXT

The importance of rehabilitation and evaluation prior to return to sport (RTS) in patients undergoing anterior cruciate ligament reconstruction has been reported.

OBJECTIVE

This study sought to investigate current perspectives of Australian orthopedic surgeons on rehabilitation and RTS evaluation.

DESIGN

Survey.

PARTICIPANTS

Members of the Australian Knee Society.

MAIN OUTCOME MEASURES

A 14-question survey was disseminated to Australian Knee Society members (orthopedic surgeons) to investigate (1) preferred graft choice, (2) estimated retear rate, (3) importance of preoperative and postoperative rehabilitation, and (4) preferred timing of RTS and evaluation prior to RTS discharge.

RESULTS

Of all 85 Australian Knee Society members contacted, 86% (n = 73) responded. Overall, 66 respondents (90.4%) preferentially used hamstring tendon autografts. All surgeons estimated their retear rate to be ≤15%, with 31 (42.5%) <5%. Twenty-eight surgeons (38.4%) reported no benefit in preoperative rehabilitation. The majority of surgeons (82.2%-94.5%) reported that postoperative rehabilitation was important within various periods throughout the postoperative timeline. Most surgeons did not permit RTS until ≥9 months (n = 56, 76.7%), with 17 (23.3%) allowing RTS between 6 and 9 months. The most highly reported considerations for RTS clearance were time (90.4%), functional capacity (90.4%), and strength (78.1%). Most commonly, knee strength and/or function was assessed via referral to a preferred rehabilitation specialist (50.7%) or with the surgeon at their practice (11.0%).

CONCLUSIONS

This survey revealed variation in beliefs and practices surrounding rehabilitation and RTS evaluation. This is despite the current evidence demonstrating the benefit of preoperative and postoperative rehabilitation, as well as the emerging potential of RTS assessments consisting of strength and functional measures to reduce reinjury rates.

A Secondary Injury Prevention Program May Decrease Contralateral Anterior Cruciate Ligament Injuries in Female Athletes: 2-Year Injury Rates in the ACL-SPORTS Randomized Controlled Trial

OBJECTIVE

To determine whether the addition of perturbation training to a secondary injury prevention program reduces the rate of second anterior cruciate ligament (ACL) injury compared to the prevention program alone.

DESIGN

Single-blinded randomized controlled trial.

METHODS

Thirty-nine female athletes who intended to return to cutting/pivoting sports were enrolled 3 to 9 months after primary anterior cruciate ligament reconstruction (ACLR). Athletes were randomized to receive a training program of either progressive strengthening, agility, plyometrics, and prevention (SAPP) (n = 20) or SAPP plus perturbation training (n = 19); each had 10 sessions over 5 weeks. Occurrence and side of second ACL injury were recorded for 2 years after primary ACLR.

RESULTS

There were 9 second ACL injuries in the 2 years after ACLR. There was no statistically significant difference in rate or side of second ACL injury between the SAPP-plus-perturbation training and SAPP groups.

CONCLUSION

Adding perturbation training to a secondary ACL injury prevention program did not affect the rate of second ACL injury in female athletes. J Orthop Sports Phys Ther 2020;50(9):523-530. Epub 1 Aug 2020. doi:10.2519/jospt.2020.9407.

A Cross-sectional Examination of Quadriceps Strength, Biomechanical Function, and Functional Performance From 9 to 24 Months After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Patients who undergo anterior cruciate ligament reconstruction (ACLR) have deficiencies in strength, functional performance, and biomechanical function at return to activity. Patients who have abnormal strength and function after ACLR may be at a greater risk for secondary injury and posttraumatic osteoarthritis.

PURPOSE

To examine quadriceps strength, functional performance, and knee biomechanics in patients who are 9, 12, 18, and 24 months after ACLR.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

We recruited 82 participants (45 female) who underwent ACLR and were cleared to return to activity . Participants were assigned to 1 of 4 groups based on their time from ACLR: 9 months (285.26 ± 8.16 days), 12 months (373.59 ± 8.81 days), 18 months (557.50 ± 11.96 days), and 24 months postoperative (741.05 ± 11.86 days). Quadriceps strength was measured concentrically at 60 deg/s. Functional performance was assessed by measuring maximal hop distances or heights during dynamic hopping/jumping tests (single-leg hop, triple hop, crossover hop, and single-leg vertical hop). Biomechanical function was evaluated during the dynamic hop tests by using peak sagittal plane knee flexion angles recorded during landings. Strength, performance, and biomechanics data were collected for both limbs and reported as symmetry scores ([injured/uninjured] × 100). Self-perceived function was measured using the International Knee Documentation Committee subjective knee form.

RESULTS

Quadriceps strength in the 9-month (77.61 ± 16.73) and 12-month (77.80 ± 13.99) groups was significantly lower (P < .01) compared with the 24-month group (92.40 ± 15.55). Self-perceived function for the 9-month group (79.33 ± 10.40) was significantly lower (P < .01) when compared with 12-month (87.58 ± 10.29), 18-month (89.81 ± 8.36), and 24-month (91.59 ± 5.70) groups. Single-leg hop distance symmetry was significantly lower (P < .01) for the 9-month group (90.01 ± 9.46) when compared with the 18-month (96.24 ± 6.47) and 24-month (96.30 ± 6.46) groups; triple hop symmetry was significantly lower (P < .05) for the 9-month group (90.26 ± 10.03) when compared with the 18-month (96.83 ± 9.60) and 24-month (95.91 ± 6.36) groups; and crossover hop was significantly lower (P < .05) for the 9-month group (88.35 ± 13.53) when compared with the 18-month (95.85 ± 8.63) and 24-month (97.10 ± 4.12) groups.

CONCLUSION

Quadriceps strength, self-perceived function, and functional performance improve 9 to 24 months after ACLR, indicating that recovery is ongoing after return to activity. Return-to-activity criteria after ACLR should objectively account for strength and function.

Return to sport after anterior cruciate ligament injury: Panther Symposium ACL Injury Return to Sport Consensus Group

PURPOSE

A precise and consistent definition of return to sport (RTS) after anterior cruciate ligament (ACL) injury is lacking, and there is controversy surrounding the process of returning patients to sports and their previous activity level. The aim of the Panther Symposium ACL Injury RTS Consensus Group was to provide a clear definition of RTS and description of the RTS continuum, as well as to provide clinical guidance on RTS testing and decision-making.

METHODS

An international, multidisciplinary group of ACL experts convened as part of a consensus meeting. Consensus statements were developed using a modified Delphi method. Literature review was performed to report the supporting evidence.

RESULTS

Key points include that RTS is characterized by achievement of the pre-injury level of sport and involves a criteria-based progression from return to participation to return to sport, and ultimately return to performance. Purely time-based RTS decision-making should be abandoned. Progression occurs along a RTS continuum with decision-making by a multidisciplinary group that incorporates objective physical examination data and validated and peer-reviewed RTS tests, which should involve functional assessment as well as psychological readiness. Consideration should be given to biological healing, contextual factors and concomitant injuries.

CONCLUSION

The resultant consensus statements and scientific rationale aim to inform the reader of the complex process of RTS after ACL injury that occurs along a dynamic continuum. Research is needed to determine the ideal RTS test battery, the best implementation of psychological readiness testing and methods for the biologic assessment of healing and recovery.

LEVEL OF EVIDENCE

IV.

Anterior cruciate ligament-return to sport after injury scale: validation of the Norwegian language version

PURPOSE

Evidence is emerging on the importance of psychological readiness to return to sport after anterior cruciate ligament (ACL) reconstruction. The ACL-Return to Sport after Injury scale (ACL-RSI) is developed to assess this. The aim of the current study was to translate ACL-RSI into Norwegian and examine the measurement properties of the Norwegian version (ACL-RSI-No).

METHODS

ACL-RSI was translated according to international guidelines. A cohort of 197 ACL-reconstructed patients completed ACL-RSI-No and related questionnaires nine months post-surgery. One hundred and forty-six patients completed hop tests and 142 patients completed strength tests. Face and structural validity (confirmative factor analysis and explorative analyses), internal consistency [Cronbach's alpha (α)], test-retest reliability [Intraclass Correlation Coefficients (ICC)], measurement error [Standard error of measurement (SEM) and smallest detectable change at individual (SDCind) and group level (SDCgroup)] and construct validity (hypotheses testing; independent t tests, Pearson's r) were examined.

RESULTS

ACL-RSI-No had good face validity. Factor analyses suggested that the use of a sum score is reasonable. Internal consistency and test-retest reliability were good (α 0.95, ICC 0.94 (95% CI 0.84-0.97) and measurement error low (SEM 5.7). SDCind was 15.8 points and SDCgroup was 2.0. Six of seven hypotheses were confirmed.

CONCLUSIONS

ACL-RSI-No displayed good measurement properties. Factor analyses suggested one underlying explanatory factor for "psychological readiness"-supporting the use of a single sum score. ACL-RSI-No can be used in the evaluation of psychological readiness to return to sport after ACL injury.

LEVEL OF EVIDENCE

III.

Strength and Power Training in Rehabilitation: Underpinning Principles and Practical Strategies to Return Athletes to High Performance

Injuries have a detrimental impact on team and individual athletic performance. Deficits in maximal strength, rate of force development (RFD), and reactive strength are commonly reported following several musculoskeletal injuries. This article first examines the available literature to identify common deficits in fundamental physical qualities following injury, specifically strength, rate of force development and reactive strength. Secondly, evidence-based strategies to target a resolution of these residual deficits will be discussed to reduce the risk of future injury. Examples to enhance practical application and training programmes have also been provided to show how these can be addressed.

Clinical Outcomes After Anterior Cruciate Ligament Injury: Panther Symposium ACL Injury Clinical Outcomes Consensus Group

A stringent outcome assessment is a key aspect of establishing evidence-based clinical guidelines for anterior cruciate ligament (ACL) injury treatment. To establish a standardized assessment of clinical outcome after ACL treatment, a consensus meeting including a multidisciplinary group of ACL experts was held at the ACL Consensus Meeting Panther Symposium, Pittsburgh, Pennsylvania, USA, in June 2019. The aim was to establish a consensus on what data should be reported when conducting an ACL outcome study, what specific outcome measurements should be used, and at what follow-up time those outcomes should be assessed. The group reached consensus on 9 statements by using a modified Delphi method. In general, outcomes after ACL treatment can be divided into 4 robust categories: early adverse events, patient-reported outcomes (PROs), ACL graft failure/recurrent ligament disruption, and clinical measures of knee function and structure. A comprehensive assessment after ACL treatment should aim to provide a complete overview of the treatment result, optimally including the various aspects of outcome categories. For most research questions, a minimum follow-up of 2 years with an optimal follow-up rate of 80% is necessary to achieve a comprehensive assessment. This should include clinical examination, any sustained reinjuries, validated knee-specific PROs, and health-related quality of life questionnaires. In the midterm to long-term follow-up, the presence of osteoarthritis should be evaluated. This consensus paper provides practical guidelines for how the aforementioned entities of outcomes should be reported and suggests the preferred tools for a reliable and valid assessment of outcome after ACL treatment.

Identifying potential patient-specific predictors for anterior cruciate ligament reconstruction outcome - a diagnostic in vitro tissue remodeling platform

Purpose

Upon anterior cruciate ligament (ACL) rupture, reconstruction is often required, with the hamstring tendon autograft as most widely used treatment. Post-operative autograft remodeling enhances graft rupture risk, which occurs in up to 10% of the patient population, increasing up to 30% of patients aged under 20 years. Therefore, this research aimed to identify potential biological predictors for graft rupture, derived from patient-specific tissue remodeling-related cell properties in an in vitro micro-tissue platform.

Methods

Hamstring tendon-derived cells were obtained from remnant autograft tissue after ACL reconstructions (36 patients, aged 12–55 years), and seeded in collagen I gels on a micro-tissue platform. Micro-tissue compaction over time – induced by altering the boundary constraints – was monitored. Pro-collagen I expression was assessed using ELISA, and protein expression of tenomodulin and α-smooth muscle actin were measured using Western blot. Expression and activity of matrix metalloproteinase 2 were determined using gelatin zymography.

Results

Only micro-tissues corresponding to younger patients occasionally released themselves from the constraining posts. Pro-collagen I expression was significantly higher in younger patients. Differences in α-smooth muscle actin and tenomodulin expression between patients were found, but these were age-independent. Active matrix metalloproteinase 2 expression was slightly more abundant in younger patients.

Conclusions

The presented micro-tissue platform exposed patient-specific remodeling-related differences between tendon-derived cells, with the micro-tissues that released from constraining posts and pro-collagen I expression best reflecting the clinical age-dependency of graft rupture. These properties can be the starting point in the quest for potential predictors for identifying individual patients at risk for graft rupture.

Comparing the Responsiveness of the Global Rating Scale With Legacy Knee Outcome Scores: A Delaware-Oslo Cohort Study

BACKGROUND

The selection of patient-reported outcome measures (PROMs) is essential for obtaining meaningful information to treat a patient, determine a plan of care, and make clinical decisions; however, the process of selecting PROMs for clinical care is difficult, with the need to balance these multiple factors. Variation makes it difficult to compare data across providers and studies.

HYPOTHESIS/PURPOSE

The purpose was to determine the responsiveness of 4 PROMs via effect size and the presence of a ceiling effect in the 5 years after anterior cruciate ligament reconstruction (ACLR). We hypothesized that the single-item Global Rating Scale (GRS) would have an effect size and ceiling effect similar to the commonly used legacy PROMs.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

Of the 300 participants, 218 had ACLR, completed postoperative progressive criterion-based rehabilitation early after surgery, and were followed for 5 years. We collected data based on the GRS, the Knee Outcome Survey-Activities of Daily Living Scale (KOS-ADLS), the International Knee Documentation Committee-Subjective Knee Form (IKDC-SKF), and the KOOS (Knee injury and Osteoarthritis Outcome Score) before and after training and at 6, 12, 24, and 60 months after ACLR.

RESULTS

The IKDC-SKF had the largest effect sizes and lowest ceiling effects. The GRS had a similar size and change in both effect size and ceiling effect when compared with the longer PROMs. The GRS and IKDC-SKF had a correlation of 0.72, and the GRS had a minimal detectable change of 2.9 or 4.8, depending on methodology.

CONCLUSION

The GRS responded similarly to the IKDC-SKF, KOS-ADLS, and KOOS and was responsive to patient change. The ease of use and patient-specific nature of the question means that it may be appropriate to use the GRS in clinical care as a consistent measure throughout the course of rehabilitation.

Importance of functional performance and psychological readiness for return to preinjury level of sports 1 year after ACL reconstruction in competitive athletes

PURPOSE

This study aimed to identify independent predictive factors for return to sports (RTS) after anterior cruciate ligament (ACL) reconstruction in competitive-level athletes and to determine optimal cut-off values for these factors at 6 months after surgery.

METHODS

A total of 124 competitive athletes (50 males and 74 females; mean age, 17.0 years; preinjury Tegner activity scale > 7) who underwent primary ACL reconstruction were enrolled. Assessments at 6 months after surgery consisted of knee functional tests [quadriceps index, hamstrings index, and single-leg hop for distance (SLH)] and 2 self-report questionnaires [IKDC subjective score and ACL-Return to Sport after Injury scale (ACL-RSI)]. At 1 year after surgery, athletes were classified into the RTS group (n = 101) or non-RTS group (n = 23) based on self-reported sports activities. After screening possible predictive factors of RTS, multivariate logistic regression and receiver operating characteristic curve analyses were performed to identify independent factors.

RESULTS

Multivariate logistic regression analysis identified SLH (odds ratio, 2.861 per 10 unit increase; P < 0.001) and ACL-RSI (odds ratio, 1.810 per 10 unit increase; P = 0.001) at 6 months as independent predictors of RTS at 1 year after surgery. Optimal cut-off values of SLH and ACL-RSI were 81.3% (sensitivity = 0.891; specificity = 0.609) and 55 points (sensitivity = 0.693; specificity = 0.826), respectively.

CONCLUSION

In competitive athletes, SLH < 81% and ACL-RSI < 55 points at 6 months after surgery were associated with a greater risk of unsuccessful RTS at 1 year after surgery. SLH and ACL-RSI at 6 months could serve as screening tools to identify athletes who have difficulties with returning to sports after ACL reconstruction.

LEVEL OF EVIDENCE

III.

Return to sport testing at 6 months after arthroscopic shoulder stabilization reveals residual strength and functional deficits

OBJECTIVES

A good outcome after arthroscopic stabilization for recurrent shoulder instability is often characterized by a successful return to sport while minimizing complications. There is currently no consensus regarding timing or objective criteria for return to sport. The objective of this study is to evaluate the ability of postoperative patients to meet expected goals by using standardized objective evaluations of strength and physical function.

METHODS

Forty-three (10 females, 76.7% male) subjects (mean age, 18.1 ± 3.7 years) who underwent arthroscopic shoulder stabilization surgery (anterior or posterior) from 2016 until 2018 were referred during their postoperative rehabilitation for functional testing at 6 months postoperatively to evaluate their readiness for return to sport. The Closed Kinetic Chain Upper Extremity Stability test and Unilateral Seated Shot Put test were used to assess shoulder function. Posterior rotator cuff activation was evaluated using a repetition to failure technique with 5% body weight at 0° and 90° of abduction with the goal of 90% of nonoperative extremity. Isokinetic strength testing of external rotation (ER) and internal rotation (IR) was evaluated using a Biodex isokinetic dynamometer at angular velocities of 60° and 180° per second, and a passing score was considered achieving 90% of nonoperative shoulder strength at both 60° and 180° per second.

RESULTS

All subjects were competitive athletes (20 collegiate, 23 high school). The dominant extremity was the surgical extremity in 22 subjects. Only 5 subjects were able to successfully pass the battery of tests for strength and function. Strength testing revealed that 7 patients achieved 90% of the strength of the nonoperative extremity in both repetitions to failure (23 of 43) and comparative isokinetic testing (7 of 43). More subjects were able to meet IR strength (20 of 43) than ER strength (12 of 43) goals. Functional test goals were more frequently achieved, with 26 of 43 subjects meeting both functional test goals (33 Closed Kinetic Chain Upper Extremity Stability, 34 Unilateral Seated Shot Put). Only 2 subjects were able to achieve strength goals but did not pass functional tests, whereas 21 subjects passed functional tests without meeting strength goals.

CONCLUSION

A substantial number of athletes in our cohort do not meet the expected goals for their operative shoulder in achieving appropriate function and strength, compared with the contralateral shoulder. Functional goals were more often met than strength. IR strength goals were more frequently achieved than ER strength. Strength and functional testing could provide more reliable criteria than arbitrary passage of time for return to play after shoulder stabilization surgery.

Using Normative Data and Unilateral Hopping Tests to Reduce Ambiguity in Return-to-Play Decisions

CONTEXT

After a lower extremity injury, patients often return to sport (RTS) when the injured limb's performance on unilateral hopping tests is similar to that of the uninjured limb. However, the exact target symmetry value patients must reach before the RTS is unclear.

OBJECTIVE

To identify variables that predict limb symmetry index (LSI) values on 6 unilateral hopping tests in healthy, physically active adults.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

In total, 275 healthy, physically active adults, consisting of recreational athletes (n = 198), National Collegiate Athletic Association Division I student-athletes (n = 56), and Army Reserve Officer Training Corps cadets (n = 21), volunteered to participate (143 men, 132 women, age = 20.16 ± 2.19 years, height = 172.66 ± 10.22 cm, weight = 72.64 ± 14.29 kg).

INTERVENTION(S)

Each participant completed 3 speed (6-m crossover-hop, side-hop, figure-8 hop) and 3 distance (triple-crossover-hop, lateral-hop, medial-hop) functional performance tests on both limbs.

MAIN OUTCOME MEASURE(S)

Mean performance of the dominant and nondominant limbs and LSI values. Two multiple regression models were used to find variables that might help to predict a participant's LSI for each functional performance test.

RESULTS

The models helped to predict limb symmetry for 10 of the 12 multiple regressions. Unilateral limb performance was the best predictor of LSI values, as it was statistically significant in 11 of the 12 regression models. Sex and body mass index were significant predictor variables for the side hop and figure-8 hop, respectively.

CONCLUSIONS

We found significant predictor variables that clinicians can use in the absence of baseline testing to determine patient-specific LSI values. Individualizing RTS decisions in this way may help to minimize subjectivity in the decision-making process and ensure a safe and timely return to competition.

Return to Sport After Anterior Cruciate Ligament Injury: Panther Symposium ACL Injury Return to Sport Consensus Group

Background

A precise and consistent definition of return to sport (RTS) after anterior cruciate ligament (ACL) injury is lacking, and there is controversy surrounding the process of returning patients to sport and their previous activity level.

Purpose

The aim of the Panther Symposium ACL Injury Return to Sport Consensus Group was to provide a clear definition of RTS after ACL injury and a description of the RTS continuum as well as provide clinical guidance on RTS testing and decision-making.

Study Design

Consensus statement.

Methods

An international, multidisciplinary group of ACL experts convened as part of a consensus meeting. Consensus statements were developed using a modified Delphi method. Literature review was performed to report the supporting evidence.

Results

Key points include that RTS is characterized by achievement of the preinjury level of sport and involves a criteria-based progression from return to participation to RTS and, ultimately, return to performance. Purely time-based RTS decision-making should be abandoned. Progression occurs along an RTS continuum, with decision-making by a multidisciplinary group that incorporates objective physical examination data and validated and peer-reviewed RTS tests, which should involve functional assessment as well as psychological readiness. Consideration should be given to biological healing, contextual factors, and concomitant injuries.

Conclusion

The resultant consensus statements and scientific rationale aim to inform the reader of the complex process of RTS after ACL injury that occurs along a dynamic continuum. Research is needed to determine the ideal RTS test battery, the best implementation of psychological readiness testing, and methods for the biological assessment of healing and recovery.

Females Have Earlier Muscle Strength and Functional Recovery After Bridge-Enhanced Anterior Cruciate Ligament Repair

Background: While a sex effect on outcomes following anterior cruciate ligament (ACL) reconstruction surgery has been previously documented, less is known following bridge-enhanced ACL repair (BEAR). We hypothesized that female sex would have significantly worse early functional outcomes and higher retear rates following primary repair of the ACL enhanced with a tissue-engineered scaffold. Methods: Sixty-five patients (28 males and 37 females), age 14-35 with a complete ACL tear underwent primary repair of the ACL enhanced with a tissue-engineered scaffold (bridge-enhanced ACL repair) within 45 days of injury. International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome (KOOS) scores, as well as instrumented anteroposterior (AP) laxity through KT-1000 testing and functional outcome measures were obtained at time points up to 2 years postoperatively and compared between males and females using mixed model repeated measures analyses and chi square tests. Results: There was no significant sex difference on the postoperative IKDC Subjective Score at 3, 6, 12, or 24 months or any of the five KOOS scores at 12 and 24 months. Instrumented AP laxity testing demonstrated mean (standard deviation) side-to-side differences that were similar in the two sexes at 2 years; 1.7 (2.7) mm and 1.5 (3.7) mm in females and males, respectively, p = 0.72. At 6 months postoperatively, males had a larger deficit in hamstring strength on the operated leg (14.0% vs. 1.7%; p = 0.03) and a larger deficit in quadriceps strength on the operated leg (11.3% vs. 2.0%; p = 0.004); however, no sex difference was noted at 12 or 24 months. Females demonstrated superior single leg hop testing at 6 and 12 months ([91.3% vs. 78.1%, p = 0.001], [96.9% vs. 87.0%, p = 0.01] respectively). There were no significant sex differences on ipsilateral (males; 14.3% vs. females; 13.9%, p = 1.00) or contralateral (males; 3.6% vs. females; 2.8%, p = 1.00) ACL reinjury rates. Conclusions: Female subjects had better hamstring and quadriceps strength indices at 6 months than males as well as better hop test results at the 6 and 12-month time period. Despite this, there was no significant sex difference on patient-reported outcomes and objective AP laxity testing at time points up to 2 years postoperatively. Impact statement This is the first study comparing sex specific outcomes following the bridge-enhanced ACL repair technique (BEAR). The results of this study suggest that females have earlier recovery of both muscle strength and functional outcomes compared to their male counterparts. This is an important finding when considering future modifications to postoperative care and rehabilitation in females and males following this tissue-engineered BEAR technique.

Development of Concise Physical Performance Test Batteries in Young Athletes

PURPOSE

This study aimed 1) to define the principal components of physical function assessed by 10 common lower extremity physical performance tests and 2) to derive a reduced-item set of physical performance tests that efficiently and accurately measures raw performance and limb symmetry on each underlying component in pediatric and adolescent athletes.

METHODS

This study included healthy, uninjured volunteers (n = 100) between the ages 6 and 18 yr (mean age = 11.7 ± 3.6 yr; 52 females). Subjects performed the stork balance, stork balance on BOSU® Balance Trainer, single leg squat (SLS), SLS on BOSU, clockwise and counterclockwise quadrant single leg hop (SLH), forward SLH, timed SLH, triple crossover SLH, and lower quarter Y-Balance Test™. Item reduction was performed using principal components analysis (PCA). We developed separate principal components analysis for average raw performance and side-to-side limb symmetry, with secondary analyses to evaluate consistency of results by age and sex.

RESULTS

We identified two components for average raw performance (accounting for 65.2% of the variance in total test battery) with a reduced-item set composed of five tests, and four components for limb symmetry (accounting for 62.9% of the variance in total test battery) with a reduced-item set of seven tests. The most parsimonious test suitable for screening both average raw performance and limb symmetry would consist of five tests (stork balance on BOSU, SLS on BOSU, forward SLH, timed SLH, and lower quarter Y-Balance Test™). Age- and sex-specific test batteries may be warranted.

CONCLUSION

Comprehensive screening for lower extremity average raw performance and limb symmetry is possible with short physical performance test batteries.

Better reporting standards are needed to enhance the quality of hop testing in the setting of ACL return to sport decisions: a narrative review

Background/aim

There is a lack of consistency in return to sport (RTS) assessments, in particular hop tests to predict who will sustain a reinjury following anterior cruciate ligament (ACL) reconstruction. Inconsistent test battery content and methodological heterogeneity might contribute to variable associations between hop test performance and subsequent injury. Our aim was to investigate whether commonly used hop tests are administered in a consistent manner and in accordance with reported guidelines.

Methods

We conducted a narrative review of studies that examined whether hop testing could differentiate RTS pass rates, reinjury and rerupture in athletes after ACL reconstruction. Our specific focus was on the methodological procedures of hop testing as this component is widely used to evaluate patients’ function and readiness to RTS.

Main findings

Substantial variation exists in RTS hop test administration, scoring and interpretation. Authors often failed to report important details of methods such as warm up activities, randomisation, number of trials, rest periods and landing requirements.

Conclusion

We recommend researchers provide clearer descriptions of how hop tests are performed to increase standardisation and promote accurate data collection. Absence of reporting to describe test methods and using different test procedures makes it difficult to compare study findings.

Symmetries in Muscle Torque and Landing Kinematics Are Associated With Maintenance of Sports Participation at 5 to 10 Years After ACL Reconstruction in Young Men

Background:

Long-term maintenance of sports participation is important for young men undergoing anterior cruciate ligament (ACL) reconstruction. Identifying biomechanical characteristics in patients who achieve this goal can assist in elaborating rehabilitation programs and in identifying successful recovery, but this has rarely been investigated.

Purpose:

To test the association between maintenance of sports participation at 5 to 10 years after ACL reconstruction and measures of force production and landing biomechanics in men.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A total of 30 men who underwent isolated ACL reconstruction were examined. At 5- to 10-year follow-up, associations were tested between reported outcomes of sports maintenance and objective biomechanical measures. The biomechanical tests included isokinetic knee torque and lower limb kinetics and kinematics during landing tasks. Measurements for each limb were conducted separately, and side-to-side symmetry indices (SI) were calculated. Subgroups included SI greater than +10% (ie, extreme positive), SI lower than –10% (ie, extreme negative), and SI between –10% and +10% (ie, symmetric).

Results:

At follow-up, concentric knee torque in the operated limb correlated with Tegner and Marx scores (r = 0.42-0.47; P ≤ .05). Regarding the SI of knee torque, the highest Tegner, Marx, and KOOS (Knee injury and Osteoarthritis Outcome Score) results were associated with symmetry, as opposed to patients with extreme positive or extreme negative SIs (P < .05). As for landing kinematics, Tegner score negatively correlated with knee range of motion (ROM) in the operated limb (r = –0.38; P ≤ .05). With regard to SI, hip and knee ROM correlated with Tegner, IKDC, and KOOS scores (r = 0.41-0.51; P ≤ .05). Specifically, the highest sports participation levels were associated with achieving symmetric hip and knee ROM but also with extreme positive SIs, as opposed to patients with extreme negative SIs (P < .03), indicating substantially higher ROM in the uninjured limb as compared with the operated limb.

Conclusion:

At 5 to 10 years after ACL reconstruction, maintenance of sports participation was associated with symmetric side-to-side concentric knee torque and with producing greater attenuation of hip and knee ROM during the drop jump landing in the operated limb. Therefore, eccentric load programs that can improve attenuation-phase kinematics during landing tasks may be valuable in addition to concentric training and may facilitate enhanced long-term outcomes.

Current clinical practice and return-to-sport criteria after anterior cruciate ligament reconstruction: a survey of Brazilian physical therapists

BACKGROUND

Adherence to the use of recommended measures/criteria for return to sport clearance after anterior cruciate ligament reconstruction is crucial for successful rehabilitation.

OBJECTIVES

The purpose of this study was to describe the current clinical practice of Brazilian physical therapists that treat patients after anterior cruciate ligament reconstruction, including the measures/criteria used to support the decision-making process regarding return to sport. The secondary aim was to investigate factors associated with the use of the most recommended measures/criteria for return to sport.

METHODS

An electronic survey questionnaire was sent to Brazilian physical therapists. The survey consisted of questions about demographics and professional and clinical practice data related to anterior cruciate ligament reconstruction postoperative rehabilitation and return to sport criteria. Descriptive statistics and chi-square tests were used for analyses.

RESULTS

A sample of 439 professionals participated in the survey. Only 6.4% of the physical therapists use the most recommended measures/criteria for return to sport after anterior cruciate ligament reconstruction. Professional certification in Sports Physical Therapy was the only factor associated with the use of these recommended measures/criteria (p=0.02). The measures most used for return to sport clearance were related to physical factors (65.3% to 75.1%), such as range of motion and muscle strength. A small number of professionals use questionnaires to assess functional (16.6%) and psychological (19.1%) aspects of their patients to support the decision-making process.

CONCLUSION

In their clinical practice, most Brazilian physical therapists do not use the recommended measures/criteria for return to sport after anterior cruciate ligament reconstruction.

Passing return to sports tests after ACL reconstruction is associated with greater likelihood for return to sport but fail to identify second injury risk

BACKGROUND

A limited number of patients return to sport (RTS) after an anterior cruciate ligament reconstruction (ACLR) and patients who RTS have a relatively high risk for second ACL injury. The purpose of the current study was to compare the results of a test battery between patients who returned to the pre-injury level of sport (RTS group) and patients who did not (NO-RTS group). It was hypothesized that the RTS group showed better test results.

METHODS

Sixty-four patients (age 27.8 ± 8.8 years) were included. The results of a multicomponent test battery (jump-landing task assessed with the Landing Error Scoring System (LESS), three hop tests, isokinetic strength test for quadriceps and hamstring) were compared between groups with a 2 × 2 ANOVA.

RESULTS

The RTS group showed a significantly lower LESS score (p = 0.010), significantly higher absolute scores on hop tests with both legs (injured leg: single leg hop test p = 0.013, triple leg hop test p = 0.024, side hop test p = 0.021; non-injured leg: single leg hop test p = 0.011, triple leg hop test p = 0.023, side hop test p = 0.032) and significantly greater hamstring strength in the injured leg (p = 0.009 at 60°/s, p = 0.012 at 180°/s and p = 0.013 at 300°/s). No differences in test results were identified between patients who sustained a second ACL injury and patients who did not.

CONCLUSION

Patients after ACLR with better jump-landing patterns, hop performance and greater hamstring strength have greater likelihood for RTS. However, our findings show that RTS criteria fail to identify patients who are at risk for a second ACL injury.

Evolution of Functional Recovery using Hop Test Assessment after ACL Reconstruction

The purpose of this study was to evaluate improvements in functional performance through the use of the Limb Symmetry Index of Single and Triple Hop tests between 12 and 52 weeks after anterior cruciate ligament reconstruction, and to compare these values with usual time-based and performance-based criteria used during the return to sport continuum. Repeated functional assessments using Single and Triple Hop Tests at 12, 16, 22, 26, 39 and 52 postoperative weeks were evaluated. At each session, the median and interquartile range of Limb Symmetry Index of tests were calculated and compared with the usual criteria: return to participation:≥85%, between 12-16 w; return to play:≥90%, between 26-39 w. The results indicate that the median increased over time to 39 postoperative weeks and then stabilized. For Single Hop Test, wide variability was seen at 12 and 16 weeks (interquartile range=20%); this was lower from 22 to 52 weeks (interquartile range=8-6%). At 12 weeks for Single Hop Test, the median was 83.6% and did not meet>85% criteria for return to participation. Hop tests could be interesting functional tests to follow the functional recovery and help decision-making regarding return to participation and return to play.

Hop tests and psychological PROs provide a demanding and clinician-friendly RTS assessment of patients after ACL reconstruction, a registry study

Background

There is growing interest in assessing psychological well-being in patients after anterior cruciate ligament (ACL) reconstruction. It is unknown whether an assessment of psychological outcome in addition to tests of muscle function can facilitate decisions on return to sport (RTS). Therefore, the aim of this study was to evaluate passing rates in different physical RTS test batteries, with and without the inclusion of psychological outcome measures 1 year after ACL reconstruction.

Method

In this cross-sectional cohort study a total of 320 patients (51% men) aged 18–65 years were included 1 year after ACL reconstruction. Passing rates on different muscle function (MF) test batteries (with results presented as Limb Symmetry Index (LSI)), consisting of knee extension and flexion strength tests, 3 hop tests, and 2 psychological patient-reported outcomes (PROs); Quality of Life subscale from the Knee injury and Osteoarthritis Outcome Score (KOOS QoL) and ACL Return to Sport after Injury (ACL-RSI), were evaluated 1 year after ACL reconstruction. Muscle function test batteries comprised: 2 MF tests (vertical hop and hop for distance; pass = 90% LSI); 2 MF tests and 2 PRO (pass = 90% LSI, 62.5 points on KOOS QoL and 76.6 points on ACL-RSI), 5 MF tests (2 strength and 3 hop tests, pass = 90% LSI), and 5 MF tests and 2 PRO (pass = 90% LSI, 62.5 points on KOOS QoL and 76.6 points on ACL-RSI).

Results

Passing rates in the different test batteries were 47% for 2 MF tests, 19% for 2 MF tests and 2 PROs, 29% for 5 MF tests and 13% for 5 MF tests and 2 PROs. The use of psychological PROs together with tests of muscle function gave the lowest passing rate (13%). There was a very strong correlation between passing 2 hop tests and 2 PROs and passing 5 MF tests (rφ = 0.41) as well as passing 5 MF tests and 2 PROs (rφ = 0.79).

Conclusion

The use of hop tests together with psychological PROs provides a clinician-friendly RTS test battery for assessment 1 year after ACL reconstruction as the passing rate was 19% when using 2 hop-tests combined with 2 PROs, compared with 29% when using 5 tests of MF requiring advanced testing equipment.

Limb symmetry index on a functional test battery improves between one and five years after anterior cruciate ligament reconstruction, primarily due to worsening contralateral limb function

OBJECTIVE

Evaluate change in functional performance from 1- to 5-years after anterior cruciate ligament reconstruction (ACLR).

METHODS

59 participants (38 men) aged 29 ± 16 years completed three hops and one-leg rise 1- and 5-years following ACLR. Linear mixed-effects models evaluated differences in change between the ACLR and contralateral limbs. Participants were classified with stable, improving or worsening function relative to previously published minimal detectable change thresholds. Healthy controls completed the three hops (n = 41) and one-leg rise (n = 31) as reference data.

RESULTS

The contralateral limb had a significantly greater decrease in functional performance between 1- and 5-years for the three hops, compared to the ACLR limb. Worsening was more common in the contralateral limb than the ACLR limb; resulting in significant improvements in the LSI for the single hop (mean 87% at 1-year to 95% at 5-years), side hop (77%to 86%) and one-leg rise (76% to85%). Performance of both ACLR and contralateral limbs and the LSI remained below the healthy controls.

CONCLUSION

Functional performance changes differ between limbs between 1- and 5-years post-ACLR. The LSI should not be used in isolation to evaluate functional performance changes after ACLR, as it may overestimate functional improvement, due to worsening contralateral limb function.

One in 5 Athletes Sustain Reinjury Upon Return to High-Risk Sports After ACL Reconstruction: A Systematic Review in 1239 Athletes Younger Than 20 Years

CONTEXT

Anterior cruciate ligament (ACL) reconstruction (ACLR) is frequently performed in patients younger than 20 years whose goal is to return to sport (RTS). Varying reinjury rates have been reported, and the factors responsible are unclear. Studies differ with regard to age, graft type, surgical techniques, postoperative rehabilitation, RTS guidelines, and methods used to determine ACL failures.

OBJECTIVE

To determine RTS rates; the effect of participation in high-risk sports, sex, and graft type on ACL reinjury rates; and whether objective test criteria before RTS correlate with lower reinjury rates.

DATA SOURCES

A systematic review of the literature from inception to May 31, 2019, was conducted using the PubMed and Cochrane databases.

STUDY SELECTION

Studies on transphyseal ACLR in athletes <20 years old with a minimum mean follow-up of 2 years that reported reinjury rates, the number that RTS, and detailed the type of sport were included.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

A total of 1239 patients in 8 studies were included; 87% returned to sport and 80% resumed high-risk activities. Of the patients, 18% reinjured the ACL graft and/or the contralateral ACL. Nine percent of patellar tendon autografts and 15% of hamstring autografts failed (odds ratio [OR], 0.52; P = 0.002). Of reinjuries, 90% occurred during high-risk sports. Male patients had a significantly higher rate of ACL graft failure than female patients (OR, 1.64; P = 0.01). There was no sex-based effect on contralateral ACL injuries. Only 1 study cited objective criteria for RTS.

CONCLUSION

A high percentage of athletes returned to sport, but 1 in 5 suffered reinjuries to either knee. Male patients were more likely to reinjure the ACL graft. Objective criteria for RTS were rarely mentioned or not detailed. The need for testing of knee stability, strength, neuromuscular control, agility, and psychological measures before RTS remains paramount in young athletes.

The Effects of Cognitive Loading on Motor Behavior in Injured Individuals: A Systematic Review

BACKGROUND

Research suggests that individuals with musculoskeletal injury may have difficulty negotiating physical tasks when they are combined with cognitive loads.

OBJECTIVE

Our objective was to conduct a systematic review to understand the effects of increased cognitive demand on movement patterns among individuals with musculoskeletal injuries.

METHODS

A comprehensive search of PubMed, MEDLINE, the Cumulative Index for Nursing and Allied Health Literature (CINAHL), and SPORTDiscus was conducted to find research reports that included a population that had previously experienced an ankle, knee, or low back injury, included an uninjured control group, and assessed a dual-task paradigm.

RESULTS

Forty-five full-text research reports were assessed, of which 28 studies (six ankle injury, nine knee injury, and 13 low back pain studies) were included in the review. Included studies were assessed for methodological quality and the study design extracted for analysis including the participants, cognitive and physical tasks performed, as well as outcome measures (e.g., three-dimensional kinematics, center of pressure, etc.). All studies included were cross-sectional or case-control with methodological quality scores of 17.8 ± 2.2 out of a possible 22. Twenty-five of the 28 studies found changes in motor performance with dual-task conditions compared with single tasks. Furthermore, 54% of studies reported a significant group by task interaction effect, reporting at least one alteration in injured groups' motor performance under dual-task conditions when compared with an uninjured group.

CONCLUSION

The results of this systematic review indicate that motor performance is further impaired by placing a cognitive load on individuals in populations with musculoskeletal injury. More demanding tasks such as gait appear to be more affected in injured individuals than simple balance tasks. Future investigators may want to consider the difficulty of the tasks included as well as the impact of dual-task paradigms on rehabilitation programs.

Lower Limb Kinetic Asymmetries in Professional Soccer Players With and Without Anterior Cruciate Ligament Reconstruction: Nine Months Is Not Enough Time to Restore "Functional" Symmetry or Return to Performance

BACKGROUND

Residual between-limb deficits are a possible contributing factor to poor outcomes in athletic populations after anterior cruciate ligament reconstruction (ACLR). Comprehensive appraisals of movement strategies utilized by athletes at key clinical milestones during rehabilitation are warranted.

PURPOSE

To examine kinetic parameters recorded during a countermovement jump with a force platform in healthy professional soccer players and to compare their performance with those who had undergone ACLR at different stages of their rehabilitation.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 370 male professional soccer players attended a physical screening assessment where they performed at counter jump movement protocol on dual force plates and were divided into 4 groups: group 1 (<6 months post-ACLR), group 2 (6-9 months post-ACLR), group 3 (>9 months post-ACLR), and group 4 (healthy matched controls).

RESULTS

Players in the later phases of rehabilitation increased their jump performance; however, values were significantly lower than those of healthy matched controls (P > .05). Significant between-limb differences were present for both eccentric- and concentric-phase variables (P < .05), with effect sizes ranging from moderate to very large (d = 0.42-1.35). Asymmetries were lower in players who were further away from surgery; however, between-limb differences remained significantly greater in players >9 months after ACLR versus matched controls-specifically, for concentric impulse, concentric peak force, eccentric deceleration impulse, and eccentric deceleration rate of force development asymmetry (P < .05). Logistic regression identified concentric impulse asymmetry as being most strongly associated with a history of ACLR when group prediction analysis was performed (ACLR group 1, 2, or 3 vs matched controls), with odds ratios ranging from 1.50 to 1.91.

CONCLUSION

Between-limb deficits in key eccentric and concentric loading parameters remain >9 months after ACLR, indicating a compensatory offloading strategy to protect the involved limb during an athletic performance task. Concentric impulse asymmetry could be considered an important variable to monitor during rehabilitation.

Athletes With Bone-Patellar Tendon-Bone Autograft for Anterior Cruciate Ligament Reconstruction Were Slower to Meet Rehabilitation Milestones and Return-to-Sport Criteria Than Athletes With Hamstring Tendon Autograft or Soft Tissue Allograft : Secondary Analysis From the ACL-SPORTS Trial

OBJECTIVE

Graft choices for athletes undergoing anterior cruciate ligament reconstruction (ACLR) include bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) autografts and soft tissue allografts. The objective was to assess time to meet clinical milestones by graft type in athletes who completed a return-to-sport (RTS) program after ACLR.

DESIGN

Retrospective cohort study.

METHODS

Seventy-nine athletes enrolled after ACLR (allograft, n = 18; BPTB, n = 24; HT, n = 37). Time from surgery to meet (1) enrollment criteria (12 or more weeks post surgery, 80% or greater isometric quadriceps strength index, minimal effusion, and full knee range of motion), and (2) RTS criteria (90% or greater quadriceps strength index, hop testing limb symmetry, and patient-reported outcomes) was calculated. Quadriceps strength, hop performance, and patient-reported outcomes were measured before and after training, and at 1 year post surgery. Descriptive statistics, chi-square tests, and 1-way analyses of variance (α = .05) were used to analyze differences among graft types.

RESULTS

On average, the BPTB group (28.5 ± 7.6 weeks) took longer to meet enrollment milestones than the HT (22.5 ± 7.6 weeks, P = .007) and allograft (18.9 ± 5.8 weeks, P<.001) groups. The BPTB group (44.7 ± 15.8 weeks) took longer from surgery to meet RTS criteria than the HT (32.5 ± 9.9 weeks, P = .001) and allograft (29.3 ± 9.0 weeks, P<.001) groups. After training, the quadriceps strength index was lower in the BPTB group (86.1% ± 11.4%) than it was in the HT (96.1% ± 12.9%, P = .004) and allograft (96.9% ± 5.9%, P = .009) groups.

CONCLUSION

Athletes with a BPTB autograft may take longer than athletes with an HT autograft or a soft tissue allograft to complete postoperative rehabilitation, recover quadriceps strength, and meet RTS criteria. J Orthop Sports Phys Ther 2020;50(5):259-266. Epub 27 Nov 2019. doi:10.2519/jospt.2020.9111.

INTER-RATER AND TEST-RETEST RELIABILITY OF TWO NEW SINGLE LEG SIT-TO-STAND TESTS

BACKGROUND

The single leg sit-to-stand test (SLSTST) is a functional test that assesses quadriceps strength. The original SLSTST was used to diagnose lumbar nerve root impingement/radiculopathy - specifically at the L3 and L4 level. The original SLSTST used one repetition as the requirement for a successful test, therefore it may not identify quadriceps weakness in highly functional individuals with or recovering from an athletic injury.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine the interrater and test-retest reliability of two new SLSTSTs, one for maximum number of repetitions over 30 seconds and one for time to complete five repetitions.

STUDY DESIGN

Cross-sectional, reliability study.

METHODS

Twenty healthy college-aged individuals (12 males, age: 22.5 years ± 1.37, height: 1.72 m ± 0.09; weight: 70.2 kg ± 11.0) participated in the study. Two testing sessions were held three to seven days apart, and two second-year physical therapy students served as examiners. The objective of the 30-second SLSTST was for the participant to perform as many single leg sit-to-stand repetitions they could in thirty seconds, while the five repetitions SLSTST measured how quickly the subjects could perform five single leg sit to stand repetitions. Both lower extremities were tested and Intraclass Correlation Coefficients (ICC) were calculated to determine reliability.

RESULTS

Both SLSTSTs were found to have excellent interrater and good to excellent test-retest reliability. The 30-second SLSTSTs had inter-rater ICC = 0.99 on the right and 0.98 on the left while the test-retest ICCs ranged from 0.92 to 0.94. The five repetition SLSTSTs had an inter-rater ICC = .99 on both legs while the test-retest ICC ranged from 0.87 to 0.94.

CONCLUSIONS

The results of the current study indicate that the two new SLSTSTs had good to excellent test-retest and excellent inter-rater reliability. However, more research is needed to determine if SLSTSTs can be used to identify quadriceps weakness in individuals with recovering from an athletic injury or to be used as a return-to-sport (RTS) assessment.

LEVELS OF EVIDENCE

Level 2.

Australian Footballers Returning from Anterior Cruciate Ligament Reconstruction Later than 12 Months have Worse Outcomes

BACKGROUND

There is evidence that early return to competition post-anterior cruciate ligament (ACL) injury increases risk of re-injury.

AIMS

To compare subsequent ACL and other injury risks following ACL reconstruction for Australian Football League (AFL) players returning to competition at different times post-injury.

METHODS

AFL players returning from ACL reconstruction in the 1992-2014 seasons were divided into three groups based on return to competition time (< 10, 10-12 and > 12 months). Non-reconstructed injuries and artificial ligament reconstructions were excluded. Subsequent ACL injury rates were calculated based on time since injury and number of return matches played. Risk of other knee and hamstring muscle injuries was also calculated.

RESULTS

There were 233 ACL reconstructions that returned to play in the AFL during the time period under study and met our inclusion criteria. The per-game risk of subsequent ACL injury decreased with a log decay from 1.2 to 0.15% during the first 20 games back (R ² = 0.43). Players returning at > 12 months had higher overall percentage of future career games missed through subsequent ACL injuries (4.8% vs. 2.4%), and through all hamstring and knee injuries combined (12.6% vs. 8.4%) than players who returned at ≤ 12 months (both P < 0.001). Players returning at > 12 months had higher risk of knee cartilage (3.7%) and patella tendon (0.6%) injury than those returning at 10-12 months (1.5%, 0.1%, respectively).

CONCLUSION

Players returning from ACL reconstruction at greater than 12 months had significantly higher rates of future games missed through both subsequent ACL injuries and through all hamstring and knee injuries combined. It may be true that both early and late return to play lead to suboptimal outcomes compared to average return-to-play times.

Criteria-Based Return to Sport Decision-Making Following Lateral Ankle Sprain Injury: a Systematic Review and Narrative Synthesis

OBJECTIVE

The aim of this systematic review was to identify prospective studies that used a criteria-based return to sport (RTS) decision-making process for patients with lateral ankle sprain (LAS) injury.

DESIGN

Systematic review and narrative synthesis.

DATA SOURCES

The PubMed (MEDLINE), Web of Science, PEDro, Cochrane Library, SPORTDiscus (EBSCO), ScienceDirect, and Scopus databases were searched to 23 November 2018.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies were included if they prospectively applied a criteria-based RTS decision-making process for patients with LAS injury, but were excluded if they merely gathered outcome measures at the RTS time point. Studies were also excluded if patients were recovering from ankle fracture, high ankle sprain, medial ankle sprain, chronic ankle instability or complex ankle injury.

RESULTS

No studies were identified that used a criteria-based RTS decision-making process for patients with LAS injury. We were unable to conduct a quantitative synthesis or meta-analysis, therefore we provide a narrative synthesis of relevant questionnaires, as well as clinical and functional assessments commonly used in studies retrieved in the search.

CONCLUSION

There are currently no published evidence-based criteria to inform RTS decisions for patients with an LAS injury. Based on our narrative synthesis, we propose a number of variables that could be used to develop a criteria-based RTS decision paradigm. Future research should aim to reach consensus on these variables and apply them to actual RTS decisions within prospective study designs. Furthermore, we suggest that complex systems theory and the RTS continuum could be used to inform the development of an RTS decision-making paradigm for athletes with LAS injury.

Principles of Motor Learning to Support Neuroplasticity After ACL Injury: Implications for Optimizing Performance and Reducing Risk of Second ACL Injury

Athletes who wish to resume high-level activities after an injury to the anterior cruciate ligament (ACL) are often advised to undergo surgical reconstruction. Nevertheless, ACL reconstruction (ACLR) does not equate to normal function of the knee or reduced risk of subsequent injuries. In fact, recent evidence has shown that only around half of post-ACLR patients can expect to return to competitive level of sports. A rising concern is the high rate of second ACL injuries, particularly in young athletes, with up to 20% of those returning to sport in the first year from surgery experiencing a second ACL rupture. Aside from the increased risk of second injury, patients after ACLR have an increased risk of developing early onset of osteoarthritis. Given the recent findings, it is imperative that rehabilitation after ACLR is scrutinized so the second injury preventative strategies can be optimized. Unfortunately, current ACLR rehabilitation programs may not be optimally effective in addressing deficits related to the initial injury and the subsequent surgical intervention. Motor learning to (re-)acquire motor skills and neuroplastic capacities are not sufficiently incorporated during traditional rehabilitation, attesting to the high re-injury rates. The purpose of this article is to present novel clinically integrated motor learning principles to support neuroplasticity that can improve patient functional performance and reduce the risk of second ACL injury. The following key concepts to enhance rehabilitation and prepare the patient for re-integration to sports after an ACL injury that is as safe as possible are presented: (1) external focus of attention, (2) implicit learning, (3) differential learning, (4) self-controlled learning and contextual interference. The novel motor learning principles presented in this manuscript may optimize future rehabilitation programs to reduce second ACL injury risk and early development of osteoarthritis by targeting changes in neural networks.

Poor functional performance 1 year after ACL reconstruction increases the risk of early osteoarthritis progression

Background

Not meeting functional performance criteria increases reinjury risk after ACL reconstruction (ACLR), but the implications for osteoarthritis are not well known.

Objective

To determine if poor functional performance post-ACLR is associated with risk of worsening early osteoarthritis features, knee symptoms, function and quality of life (QoL).

Methods

Seventy-eight participants (48 men) aged 28±15 years completed a functional performance test battery (three hop tests, one-leg-rise) 1 year post-ACLR. Poor functional performance was defined as <90% limb symmetry index (LSI) on each test. At 1 and 5 years, MRI, Knee injury Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee (IKDC) subjective form were completed. Primary outcomes were: (i) worsening patellofemoral and tibiofemoral MRI-osteoarthritis features (cartilage, bone marrow lesions (BMLs) and meniscus) and (ii) change in KOOS and IKDC scores, between 1 and 5 years.

Results

Only 14 (18%) passed (≥90% LSI on all tests) the functional test battery. Poor functional performance on the battery (all four tests <90% LSI) 1 year post-ACLR was associated with 3.66 times (95% CI 1.12 to 12.01) greater risk of worsening patellofemoral BMLs. A triple-crossover hop <90% LSI was associated with 2.09 (95% CI 1.15 to 3.81) times greater risk of worsening patellofemoral cartilage. There was generally no association between functional performance and tibiofemoral MRI-osteoarthritis features, or KOOS/IKDC scores.

Conclusion

Only one in five participants met common functional performance criteria (≥90% LSI all four tests) 1 year post-ACLR. Poor function on all four tests was associated with a 3.66 times increased risk of worsening patellofemoral BMLs, and generally not associated with decline in self-reported outcomes.

The Warrior Athlete Part 2-Return to Duty in the US Military: Advancing ACL Rehabilitation in the Tactical Athlete

Rehabilitation following an anterior cruciate ligament reconstruction is a crucial component of the healing and recovery process and full return to duty/play in the tactical modern-day warfighter. The burden of anterior cruciate ligament injuries and subsequent loss of readiness in these military warfighters highlights one of the most significant gaps in musculoskeletal injury care today. Emphasis must be placed on early weight-bearing and range of motion (ROM), namely in this athlete population, to best facilitate a timely care and recovery process. Preoperative rehabilitation should commence immediately following the diagnosis of an anterior cruciate ligament tear, because one of the best predictors of postoperative ROM is preoperative ROM. Recent advances in rehabilitation technology such as Alter-G treadmills, inertial measurement units, and blood flow restriction therapy systems, have demonstrated success in the early rehabilitation of tactical athletes. Alter-G treadmills allow for early weight-bearing with reduced impact and progression in ROM following operative management, while inertial measurement units have been applied to tailoring rehabilitation protocols specifically to an athlete's unique functional deficits. When used in conjunction with a fined tune rehabilitation protocol, implemented by a well versed clinical team, these treatment techniques can greatly expedite the return to duty process and limit long-term complications.

CRITERIA-BASED RETURN TO SPRINTING PROGRESSION FOLLOWING LOWER EXTREMITY INJURY

In the terminal phases of athletic rehabilitation, transitioning back to sport is a critical aspect to prepare an athlete for return to full participation. Numerous interval sport programs have been published in the literature and return to sports guidelines and criteria-based progressions for returning to sport have been published, but no such protocol exists for returning to the task of sprinting. Any field or court athlete must be able to sprint as part of his/her sport demands. Because of the absence of a specific progression, sports rehabilitation professionals lack knowledge about objective criteria to progress to sprinting as well as a progressive program to do so. Given that sports rehabilitation professionals have limited visits to complete rehabilitation or their athletes have limited financial resources to do so, it is imperative that a structured, criteria-based progression be available. The purpose of this clinical suggestion is to provide a criteria-based return to sprinting progression.

LEVEL OF EVIDENCE

5.

Comparison of Continuous Adductor Canal and Femoral Nerve Blocks for Analgesia and Return of Quadriceps Function After Anterior Cruciate Ligament Reconstruction in Adolescent Patients

PURPOSE

To compare early pain relief and late quadriceps function after anterior cruciate ligament reconstruction (ACLR) with hamstring autograft in adolescent patients treated with either a continuous femoral nerve block (cFNB) or continuous adductor canal block (cACB).

METHODS

We retrospectively reviewed a consecutive series of adolescent patients who underwent ACLR and received either a cACB or cFNB for postoperative pain management. Over a 1-year period, all patients underwent ACLR with cFNBs. Over the subsequent 9 months, all patients underwent their ACLR with cACBs. Patient demographics, postoperative pain scores, opioid consumption, satisfaction and complications, and dates and results of quadriceps function derived at the Return to Sports evaluation were compared.

RESULTS

Ninety-one patients (53 cFNB, 38 cACB) were reviewed. There were no differences in the demographics of the 2 groups. There were no statistically significant differences between groups in variations in postoperative pain scores (P = .21), or satisfaction with the blocks (P = .93). Patients in the cFNB group consumed a greater number of opioid doses on postoperative day 3 (2.2 ± 2.1 doses cFNB, 1.1 ± 1.6 doses cACB, P = .03) and a greater number of opioid doses overall for postoperative days 1 to 3 (mean 6.8 ± 5.3 doses cFNB, 3.8 ± 2.1 doses cACB, P = .03). There was no difference in time to return of acceptable quadriceps strength and function when comparing the 2 groups (30.9 ± 7.7 weeks cFNB, 28.9 ± 6.6 weeks cACB, P = .087).

CONCLUSIONS

We found few differences in postoperative analgesic requirements when comparing patients who underwent ACLR with hamstring autograft with a cACB to those who underwent a similar procedure with a cFNB. Return of quadriceps strength and function by six months did not appear to vary with regional technique, either cACB or cFNB, employed at surgery.

LEVEL OF EVIDENCE

III, Retrospective comparative study.

Leg asymmetry and muscle function recovery after anterior cruciate ligament reconstruction in elite athletes: a pilot study on slower recovery of the dominant leg

The aim of this study was to examine performance in hopping tests in male athletes after anterior cruciate ligament reconstruction (ACLR) in the 4-to-6 months post-surgery period. A total of 36 athletes (24 ACLR and 12 controls) participated in this study. The ACLR group consisted of athletes who had undergone an ACLR on their dominant side (ACL DG n=16) or non-dominant side (ACL NDG n=8). Participants completed the following functional tests: a single-leg hop (SLH), single-leg triple hop (SL3H) and single-leg counter movement jump (SLCMJ), then the limb symmetry index (LSI) was calculated. There were no significant differences between the dominant and the non-dominant legs for all functional tests when comparing the ACL DG and the ACL NDG at 6 months after surgery. At 6 months after ACLR, the LSI of the two legs was within acceptable values, whether the athlete had the operation on their dominant or non-dominant leg (except the mean LSI for the ACL DG in the SLCMJ test). Furthermore, the control group showed higher performances as compared to the ACL group for all variables at 6 months after surgery, despite acceptable LSI. We concluded that an early return to “full participation to training” is not recommended in participants who have undergone an ACLR with patellar tendon grafts.

Quadriceps muscle compensatory activations are delayed following anterior cruciate ligament reconstruction using hamstring tendon graft

BACKGROUND

Compensatory and anticipatory quadriceps activation (CQA and AQA) in response to postural perturbations are essential for functional stability of the knee. This study aimed at investigating CQA and AQA before and after anterior cruciate ligament reconstruction (ACLR) using hamstrings graft.

METHODS

Twelve participants with ACLR and 12 healthy controls were exposed to 10 either unpredictable or predictable perturbations of the knee before ACLR (T1), two months (T2) and six months (T3) after surgery. Latencies of CQA and AQA in vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM) were measured.

RESULTS

Latency of CQA was delayed in ACLR compared to controls at T1 for VL (105 ± 25 vs. 57 ± 9 ms; P < .001), RF (102 ± 23 vs. 56 ± 9 ms; P < .001) and VM (107 ± 24 vs. 66 ± 16 ms; P < .001), at T2 for VL (68 ± 14 vs. 55 ± 10 ms; P < .01) and at T3 for VL (105 ± 22 vs. 58 ± 7 ms; P < .001), RF (102 ± 22 vs. 58 ± 12 ms; P < .001) and VM (106 ± 20 vs. 63 ± 8 ms; P < .001). AQA occurred earlier in ACLR than in controls at T1 for VL (-82 ± 64 vs. -14 ± 11 ms; P < .05) and VM (-105 ± 68 vs. -9 ± 12 ms; P < .05).

CONCLUSION

CQA are delayed following ACLR with hamstring graft and should be addressd by post-surgical rehabilitation.

Hop tests can result in higher limb symmetry index values than isokinetic strength and leg press tests in patients following ACL reconstruction

PURPOSE

Quadriceps weakness is a common clinical sign following anterior cruciate ligament injury and reconstruction surgery (ACLR). The aim of this study was to compare strength deficits and the limb symmetry index (LSI) from three different types of functional tests: isokinetic dynamometry, hop test, and leg press.

METHODS

A total of 26 subjects with ACLR (average 8.3 months post-operation) participated in the study. The peak knee extension torque was tested with isokinetic dynamometry at 60/180/300 °/s (ISO60/180/300). Hop distance was tested during single hop (SH) and triple hop (TH). Unilateral peak leg power (POWER) was tested during a bilateral leg press test. LSI was calculated as the ratio of the involved limb over the uninvolved limb values. Pearson correlation coefficients and paired t-tests were used to establish relationships among ISO60/180/300, SH/TH, and POWER values and compare these values between the limbs, respectively. Within-subject one-way analysis of variance (ANOVA) with post hoc analyses was used to compare LSI values among different tests.

RESULTS

ISO60/180/300 values were significantly positively correlated with SH/TH and POWER (P < 0.05), while SH/TH and POWER values were not significantly correlated. Significant limb differences were found in all tests (P = 0.001-0.008). ANOVA revealed significant LSI differences among different tests. Specifically, post hoc analyses revealed that LSI during SH was significantly higher than LSI during ISO60. Similarly, LSI during TH was significantly higher than LSIs from ISO60, ISO180, and POWER tests.

CONCLUSIONS

Peak knee extension torque values were positively associated with hop distance and leg power during the leg press test. However, LSI values should be interpreted with caution as hop tests provided significantly higher LSI values than isokinetic testing. Both isokinetic dynamometry and unilateral leg press machine could be used to isolate and strengthen the quadriceps in the involved limb. The current "gold standard" isokinetic testing at slow speed (ISO60) provided the lowest LSI value among all functional tests; therefore, the current study supported a continued use of isokinetic testing when examining individual's readiness and return-to-sport.

LEVEL OF EVIDENCE

III.