Anterior Cruciate Ligament Reconstruction Surgery: Creating a Permissive Healing Phenotype in Military Personnel and Civilians for Faster Recovery

Introduction

Anterior cruciate ligament (ACL) rupture in military personnel and civilians can be a devastating injury. A service member is 10 times more likely to suffer an ACL injury than their civilian counterparts, and despite successful surgical stabilization, 4%-35% will develop arthrofibrosis, over 50% will not return to full active duty, and up to 50% will develop post-traumatic osteoarthritis (PTOA) within 15 years. Equally concerning, woman are 2 to 8 times more likely to experience ACL injuries than men, which represents a major knowledge gap.

Materials and Methods

A comprehensive literature search was performed in December 2021 using structured search terms related to prevalence, risk factors, disease progression, and treatment of ACL injury and reconstruction. The literature search was conducted independently by two researchers using PubMed, Cochrane, and Embase databases, with inclusion of articles with military, civilian, and sex relevance, and exclusion of most papers with a publication date greater than 10 years. The resources used for the review reflect the most current data, knowledge, and recommendations associated with research and clinical findings from reliable international sources.

Results

Currently, there is no effective system-based drug therapy that creates a “permissive environment” to reduce synovial and cartilage stress after ACL injury and reconstruction and prevent secondary complications. We argue that progress in this area has been hampered by researchers and clinicians failing to recognize that (1) an ACL injury is a system’s failure that affects the whole joint, (2) the early molecular events define and perpetuate different injury phenotypes, (3) male and female responses may be different and have a molecular basis, (4) the female phenotype continues to be under-represented in basic and clinical research, and (5) the variable outcomes may be perpetuated by the trauma of surgery itself. The early molecular events after ACL injury are characterized by an overexpression of joint inflammation, immune dysfunction, and trauma-induced synovial stress. We are developing an upstream adenosine, lidocaine, and magnesium therapy to blunt these early molecular events and expedite healing with less arthrofibrosis and early PTOA complications.

Conclusions

ACL injuries continue to be a major concern among military personnel and civilians and represent a significant loss in command readiness and quality of life. The lack of predictability in outcomes after ACL repair or reconstruction underscores the need for new joint protection therapies. The male–female disparity requires urgent investigation.

Trends in Anterolateral Ligament Reconstruction and Lateral Extra-articular Tenodesis With ACL Reconstruction in Children and Adolescents

Background:

Anterolateral ligament reconstruction (ALLR) and lateral extra-articular tenodesis (LET) show promise in lowering the risk of rerupture after anterior cruciate ligament reconstruction (ACLR), but there are little data on surgeon practices and preferences in children and adolescents.

Purpose:

To quantify surgeon practices regarding ALLR and LET in the pediatric population.

Study Design:

Cross-sectional study.

Methods:

An electronic survey was administered to 87 surgeons in the Pediatric Research in Sports Medicine society. The questionnaire asked several questions about surgeon and practice characteristics as well as indications, preferences, and techniques for ALLR or LET in the context of primary and revision pediatric ACLR. Chi-square and Fisher exact tests were used to evaluate factors that affect surgical preferences.

Results:

A total of 63 surgeons completed the survey, of whom 62% performed ≥50 pediatric ACLRs annually; 56% sometimes performed anterolateral augmentation with primary ACLR, and 79% with revision ACLR. The most common indications for ALLR or LET in the primary setting were high-grade pivot shift, knee hyperextension, generalized laxity, and type of sports participation. Surgeons whose practice was >75% sports medicine were more likely to perform ALLR or LET with both primary and revision ACLR (P = .005 and P < .001, respectively). Those who had completed a sports medicine fellowship were more likely to perform these procedures than those with only pediatric orthopaedic training, in both primary (68% vs 36%; P = .01) and revision scenarios (92% vs 60%; P = .002). Of the 28 respondents who did not perform ALLR or LET with primary ACLR, 75% cited insufficient evidence as the reason. However, 96% of surgeons who did perform these procedures expressed interest in studying them prospectively, and 87% were willing to randomize patients.

Conclusion:

Findings indicated that 56% of pediatric sports surgeons sometimes perform anterolateral augmentation with primary ACLR and 79% with revision ACLR. Surgeons with sports medicine fellowship training or a mostly sports practice were more likely to perform these procedures. Insufficient evidence was the most common reason given by surgeons who did not perform anterolateral augmentation. However, there was substantial willingness to prospectively study and even randomize pediatric patients to assess the impact of ALLR or LET in this population.

Wearable Dual Polarized Electromagnetic Knee Imaging System

With the increasing uptake of sport activities, onsite detection of associated knee injuries at early stages is in high demand to avoid severe ligament tear and long treatment period. Portable electromagnetic imaging (EMI) systems have the potential to meet that demand, but there are challenges. For example, EMI is based on the contrast in the dielectric properties due to the accumulated fluid after knee injury. However, that fluid can be in any shape and orientation. Therefore, to capture enough data for processing, EMI should operate as a dual-polarized wearable system with compact antennas. Thus, the proposed system is a textile brace worn on the knee and consists of an 8-element dual-polarized aperture antenna array, which is matched with the knee. Each of the utilized antennas is fed by two orthogonal coaxial feed, occupies a small size of 36 ×36 ×3.1 mm³, and is backed by a full ground plane for unidirectional radiation. The antenna covers the band 0.7-3.3 GHz (130%), with front to back ratio of more than 10 dB. The textile wool-felt is used as the substrate to enable building flexible brace system. The system's capability to reconstruct knee images with different injuries is verified on realistic knee models and phantoms. The double stage delay, multiply and sum algorithm (DS-DMAS) is used to reconstruct those images, which demonstrate the efficiency of the dual-polarized system and its superiority over single-polarized systems.

Trends in Australian knee injury rates: An epidemiological analysis of 228,344 knee injuries over 20 years

BACKGROUND

Acute knee injuries are a key predisposing risk factor for knee osteoarthritis. Public health interventions require in-depth epidemiological evidence to determine which knee injuries are problematic in critical age and sex demographics.

METHODS

Descriptive epidemiological analysis of longitudinal data on knee injuries (July 1998 - June 2018) from the National Hospital Morbidity Database in Australia were studied. The main outcomes where the population-related knee injury frequency, incidence per 100,000 and annual growth rate (%) over the 20-year observation period. Age-group and sex differences were also studied to determine demographic-specific trends.

FINDINGS

228,344 knee injuries were diagnosed over the 20-year analysis period. Significantly rising annual incidences were observed for total knee injuries, anterior cruciate ligament (ACL) injuries and knee contusions in males and females. Posterior cruciate ligament (PCL) injuries and knee dislocations were also rising in females, but not males. Greater annual growth rates were observed for females compared to males for total knee injuries, knee contusions, PCL injuries and knee dislocations. Demographic analysis revealed that the highest annual growth rate in injury incidence (10.4%) was observed for ACL injuries in females aged 5-14 years old.

INTERPRETATION

Increasing annual incidence of knee injuries was observed over the 20-year period. Males have a higher incidence of knee injury per capita than females, but the gap appears to have narrowed over the 20-year analysis period. Younger Australians show a precipitous rise in the annual number of ACL injuries, particularly for females aged 5-14 years. These trends warrant urgent intervention.

FUNDING

None.

Knee strength deficits following anterior cruciate ligament reconstruction differ between quadriceps and hamstring tendon autografts

PURPOSE

To compare patient reported outcomes and functional knee recovery following anterior cruciate ligament (ACL) reconstruction using either a quadriceps tendon (QT) or hamstring tendon (HT) autograft.

METHODS

Thirty-five QT patients (age 20; range 15-34 years) participated in this study and were matched for gender, age and pre-injury activity level to 70 HT (age 20; range 15-32 years) patients. The following assessments were performed at 6 and 12 months post-operatively; standardized patient-reported outcome measures (IKDC, KOOS-QOL, ACL-RSI, Marx activity, anterior knee pain), knee range of motion (passive and active), anterior knee laxity, hop tests (single and triple crossover hop for distance), and isokinetic strength of the knee extensors and flexors. All dependent variables were analysed using a two-way mixed ANOVA model, with within (Time; 6 and 12 months) and between-subject (Graft; QT and HT) factors.

RESULTS

Patient reported outcome measures and hop performance improved between 6 and 12 months (p < 0.001), however no significant differences in either patient-reported outcomes or hop performance were found between the two grafts. Isokinetic strength testing showed both groups improved their peak knee extensor strength in the operated limb between 6 and 12 months (p < 0.001), but the QT group had significantly lower knee extensor strength symmetry at both time points compared to HT at 60 deg/s (p < 0.001) and 180 deg/s (p < 0.01). In contrast, the QT group had significantly greater knee flexor strength symmetry at both time points compared to HT at 60 deg/s (p < 0.01) and 180 deg/s (p = 0.01), but knee flexor strength limb symmetry did not significantly improve over time in either group.

CONCLUSION

Recovery of knee function following either QT or HT ACL reconstruction continues between 6 and 12 months after surgery. However, knee extensor strength deficits in the QT group and knee flexor strength deficits in the HT persisted at 12 months. This may have implications for decisions regarding return to sport.

LEVEL OF EVIDENCE

III.

Vancomycin Soaking Is Highly Cost-Effective in Primary ACLR Infection Prevention: A Cost-Effectiveness Study

BACKGROUND

Although presoaking grafts in vancomycin has been demonstrated to be effective in observational studies for anterior cruciate ligament reconstruction (ACLR) infection prevention, the economic benefit of the technique is uncertain.

PURPOSE

To 1) determine the cost-effectiveness of vancomycin presoaking during primary ACLR to prevent postoperative joint infections and 2) to establish the break-even cost-effectiveness threshold of the technique and determine its cost-effectiveness across various international health care settings.

STUDY DESIGN

Economic and decision analysis; Level of evidence, 2.

METHODS

A Markov model was used to determine cost-effectiveness and the incremental cost-effectiveness ratio of additional vancomycin presoaking compared with intravenous antibiotic prophylaxis alone. A repeated search of the PubMed, SCOPUS, and Cochrane Central Register of Controlled Trials databases, using the same criteria as a recent meta-analysis, was completed. A repeated meta-analysis of 9 cohort studies (level 3 evidence) was completed to determine the odds ratio of infection with vancomycin presoaking compared with intravenous antibiotics alone. Estimated costs of the vancomycin technique, treatment of infection, and further surgery were sourced from local hospitals and literature. Transitional probabilities for further surgery, including revision reconstruction and primary arthroplasty, were obtained from the literature. Probabilistic sensitivity analyses and a 1-way sensitivity analysis were performed to evaluate the ACLR infection rate break-even threshold for which the vancomycin technique would be no longer cost-effective.

RESULTS

The vancomycin soaking technique provides expected cost savings of $660 (USA), A$581 (Australia), and €226 (Spain) per patient. There was an improvement in the quality-adjusted life-years of 0.007 compared with intravenous antibiotic prophylaxis alone (4.297 vs 4.290). If the infection rate is below 0.014% with intravenous antibiotics alone, the vancomycin wrap would no longer be cost-effective.

CONCLUSION

The vancomycin presoaking technique is a highly cost-effective method to prevent postoperative septic arthritis after primary ACLR.

Disparities in ACL Reconstruction: the Influence of Gender and Race on Incidence, Treatment, and Outcomes

PURPOSE OF REVIEW

Anterior cruciate ligament (ACL) rupture is a common injury that has important clinical and economic implications. We aimed to review the literature to identify gender, racial and ethnic disparities in incidence, treatment, and outcomes of ACL injury.

RECENT FINDINGS

Females are at increased risk for ACL injury compared to males. Intrinsic differences such as increased quadriceps angle and increased posterior tibial slope may be contributing factors. Despite lower rates of injury, males undergo ACL reconstruction (ACLR) more frequently. There is conflicting evidence regarding gender differences in graft failure and ACL revision rates, but males demonstrate higher return to sport (RTS) rates. Females report worse functional outcome scores and have worse biomechanical metrics following ACLR. Direct evidence of racial and ethnic disparities is limited, but present. White athletes have greater risk of ACL injury compared to Black athletes. Non-White and Spanish-speaking patients are less likely to undergo ACLR after ACL tear. Black and Hispanic youth have greater surgical delay to ACLR, increased risk for loss to clinical follow-up, and less physical therapy sessions, thereby leading to greater deficits in knee extensor strength during rehabilitation. Hispanic and Black patients also have greater risk for hospital admission after ACLR, though this disparity is improving. Females have higher rates of ACL injury with inconclusive evidence on anatomic predisposition and ACL failure rate differences between genders. Recent literature has suggested inferior RTS and functional outcomes following ACLR in females. Though there is limited and mixed data on incidence and outcome differences between races and ethnic groups, recent studies suggest there may be disparities in those who undergo ACLR and time to treatment.

Meniscal Tear and ACL Injury Detection Model Based on AlexNet and Iterative ReliefF

Magnetic resonance (MR) is one of the special imaging techniques used to diagnose orthopedics and traumatology. In this study, a new method has been proposed to detect highly accurate automatic meniscal tear and anterior cruciate ligament (ACL) injuries. In this study, images in three different slices were collected. These are the sagittal, coronal, and axial slices, respectively. Images taken from each slice were categorized in 3 different ways: sagittal database (sDB), coronal database (cDB), and axial database (aDB). The proposed model in the study uses deep feature extraction. In this context, deep features have been obtained by using fully-connected layers of AlexNet architecture. In the second stage of the study, the most significant features were selected using the iterative RelifF (IRF) algorithm. In the last step of the application, the features are classified by using the k-nearest neighbor (kNN) method. Three datasets were used in the study. These datasets, sDB, and cDB, have four classes and consist of 442 and 457 images, respectively. The aDB used in the study has two class labels and consists of 190 images. The model proposed within the scope of the study was applied in 3 datasets. In this context, 98.42%, 100%, and 100% accuracy values were obtained for sDB, cDB, and aDB datasets, respectively. The study results showed that the proposed method detected meniscal tear and anterior cruciate ligament (ACL) injuries with high accuracy.

Knee joint unloading and daily physical activity associate with cartilage T2 relaxation times 1 month after ACL injury

Osteoarthritis (OA) is prevalent after anterior cruciate ligament (ACL) injury, but mechanismsunderlying its development are poorly understood. The purpose of this study was to determine if gait biomechanics and daily physical activity (PA) associate with cartilage T2 relaxation times, a marker of collagen organization and water content, 1 month after ACL injury. Twenty-seven participants (15-35 years old) without chondral lesions completed magnetic resonance imaging, three-dimensional gait analysis, and 1 week of PA accelerometry. Interlimb differences and ratios were calculated for gait biomechanics and T2 relaxation times, respectively. Multiple linear regression models adjusted for age, sex, and concomitant meniscus injury were used to determine the association between gait biomechanics and PA with T2 relaxation times, respectively. Altered knee adduction moment (KAM) impulse, less knee flexion excursion (kEXC) and higher daily step counts accounted for 35.8%-65.8% of T2 relaxation time variation in the weightbearing and posterior cartilage of the medial and lateral compartment (all p ≤ .011). KAM impulse was the strongest factor for T2 relaxation times in all models (all p ≤ .001). Lower KAM impulse associated with longer T2 relaxation times in the injured medial compartment (β = -.720 to -.901) and shorter T2 relaxation in the lateral compartment (β = .713 to .956). At 1 month after ACL injury, altered KAM impulse, less kEXC, and higher PA associated with longer T2 relaxation times, which may indicate poorer cartilage health. Statement of Clinical Significance: Gait biomechanics and daily PA are modifiable targets that may improve cartilage health acutely after ACL injury and slow progression to OA.

Subsequent surgery after primary ACLR results in a significantly inferior subjective outcome at a 2-year follow-up

PURPOSE

To analyze minimal important change (MIC), patient-acceptable symptom state (PASS) and treatment failure after reoperation within 2 years of primary ACL reconstruction and compare them with patients without additional surgery.

METHODS

This is a retrospective follow-up study of a cohort from a single-clinic database with all primary ACLRs enrolled between 2005 and 2015. Additional surgery within 2 years of the primary ACLR on the ipsilateral knee was identified using procedural codes and analysis of medical records. Patients who completed the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire preoperatively and at the 2-year follow-up were included in the study. MIC, PASS and treatment failure thresholds were applied using the aggregate KOOS (KOOS₄) and the five KOOS subscales.

RESULTS

The cohort included 6030 primary ACLR and from this 1112 (18.4%) subsequent surgeries were performed on 1018 (16.9%) primary ACLRs. 24 months follow-up for KOOS was obtained on 523 patients (54%) in the reoperation group and 2084 (44%) in the no-reoperation group. MIC; the no-reoperation group had a significantly higher improvement on all KOOS subscales, Pain 70.3 vs 60.2% (p < 0.01), Symptoms 72.1 vs 57.4% (p < 0.01), ADL 56.3 vs 51.2% (p < 0.01), Sport/Rec 67.3 vs 54.4% (p < 0.01), QoL 73.9 vs 56.3% (p < 0.01). PASS; 62% in the non-reoperation group reported their KOOS₄ scores to be satisfactory, while only 35% reported satisfactory results in the reoperated cohort (p < 0.05). Treatment failure; 2% in the non-reoperation group and 6% (p < 0.05) in the reoperation group considered their treatment to have failed.

CONCLUSION

Patients who underwent subsequent surgeries within 2 years of primary ACLR reported significantly inferior outcomes in MIC, PASS and treatment failure compared to the non-reoperated counterpart at the 2-year follow-up. This study provides clinicians with important information and knowledge about the outcomes after an ACLR with subsequent additional surgery.

LEVEL OF EVIDENCE

III.

Landing biomechanics deficits in anterior cruciate ligament reconstruction patients can be assessed in a non-laboratory setting

Landing biomechanics provide important information pertaining to second anterior cruciate ligament (ACL) injury risk in patients following ACL reconstruction (ACLR). While traditional motion analysis technologies are often impractical for use in non-laboratory settings, methods to assess landing biomechanics which are inexpensive, portable, and user-friendly have recently been developed and validated. The purpose of this study was to compare landing kinematics and kinetics between ACLR patients and uninjured controls in a non-laboratory setting. Sixteen ACLR patients (7 male/9 female, 6-12 months post-ACLR) and 16 gender-matched controls completed seven bilateral drop vertical jumps and seven unilateral drop landings on each limb. Plantar force was measured bilaterally using force sensing insoles and frontal and sagittal-plane knee kinematics were measured using two tablets, six reflective markers, and automated point tracking software. Plantar force impulse normalized symmetry index (NSI) and knee frontal plane projection angle (FPPA) range of motion were computed during bilateral landing, and knee flexion range of motion NSI was computed during unilateral landing and compared between groups using independent samples t tests. ACLR patients had larger NSIs (reflecting less symmetry) for plantar force impulse during bilateral landing (p < 0.001) and knee flexion range of motion during unilateral landing (p = 0.004). No between-group differences were observed for knee FPPA range of motion (p = 0.111). This study is an important step towards assessing landing biomechanics in non-research settings with the goal of providing quantitative injury risk metrics in a clinical setting that can be used for return to sport decision making.

Isometric dynamometry, dependent on knee angle, is a suitable alternative to isokinetic dynamometry when evaluating quadriceps strength symmetry in patients following anterior cruciate ligament reconstruction

BACKGROUND

Knee extensor strength deficits increase re-injury risk following anterior cruciate ligament reconstruction (ACLR). This study investigated whether isometric strength testing methods are a suitable alternative to isokinetic assessment for identifying knee extensor strength asymmetry.

METHODS

This study recruited 22 patients at 9-12 months after ACLR and 22 healthy controls. The single hop for distance (SHD) and knee extensor strength via isokinetic (60°/s and 120°/s) and isometric (positions of 90°, 60° and 30° of flexion, from full knee extension) methods were assessed. Absolute scores (normalized to body weight) and limb symmetry indices (LSIs) were calculated, with t-tests employed for statistical comparisons.

RESULTS

The SHD LSI was significantly higher (p < 0.01) than both isokinetic speeds and the 30° isometric position. No significant LSI differences (p > 0.01) existed within isokinetic or isometric test conditions. In ACLR patients, only the 60°/s isokinetic condition was significantly lower (p = 0.005) than the 60° isometric condition. When normalized to body weight, the operated limb in ACLR patients was significantly weaker than the non-operated limb during peak isokinetic strength testing at 60°/s (p = 0.001) and 120°/s (p = 0.010), as well as isometric testing at 30° (p = 0.009). Compared with controls, ACLR patients demonstrated significantly lower (p < 0.01) mean LSIs across most measures.

CONCLUSIONS

Assessment of knee extensor strength via isometric methods appears suitable in the absence of isokinetic testing equipment, though consideration of test angle (30° and 90° knee angles better detect asymmetries similar to isokinetic testing) is important.

Superior results of return to sport after double-bundle versus single-bundle anterior cruciate ligament reconstruction in young active patients

PURPOSE

To compare return to sport and clinical results in young active patients who underwent anatomic single-bundle (SB) versus double-bundle (DB) anterior cruciate ligament reconstruction (ACLR).

METHODS

Young active patients undergoing SB or DB ACLR from 2017 to 2019 at our institution were retrospectively reviewed. The primary outcome measures were the rate and time to return to sports, with secondary measures including the Lachman test, pivot shift test, Lysholm scores, International Knee Documentation Committee (IKDC) scores and graft rupture.

RESULTS

The study included a total of 90 patients (DB group, 42; SB group, 48), with a mean follow-up of 27.1 ± 6.1 months. Young active patients who underwent DB ACLR had a higher rate of return to pivoting sports than those who underwent SB ACLR (HR = 2.4; 95% confidence interval [CI]: 1.4, 4.1; p = 0.013). The DB group returned to pivoting sports at a mean ± SD of 11.0 ± 2.9 months compared with 12.7 ± 2.7 months in the SB group (p = 0.01). There was one traumatic failure in the SB group and one contralateral ACL rupture in the DB group. There was no significant difference in the rate and time to return to running, Lachman test, pivot-shift test, Lysholm or IKDC scores in either group.

CONCLUSION

Both anatomical SB and DB techniques achieved satisfactory clinical outcomes. DB techniques led to superior performance of return to pivoting sports but nonsignificant differences in time and rate of return to running, passive stability measurement, subjective knee function outcome and graft rupture rate in both groups at the 2-year follow-up. The DB ACLR should be considered a viable option to treat young patients with high activity demands.

LEVEL OF EVIDENCE

III.

The Role of Biodegradable Magnesium and Its Alloys in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis Based on Animal Studies

Objective: The actual efficacy of magnesium and its alloy in anterior cruciate ligament reconstruction (ACLR) was systematically evaluated to reduce the risk of translation from animal experiments to the clinic.

Methods: Databases of PubMed, Ovid-Embase, Web of Science, CNKI, Wanfang, VIP, and CBM were searched for literature in July 2021. Screening of search results, data extraction, and literature quality evaluation were undertaken independently by two reviewers.

Results and discussion: Seven articles were selected for the meta-analysis. The results showed that the mechanical properties of the femoral-tendon graft–tibia complex fixed with magnesium and its alloys were comparable to those fixed with titanium and its alloys, and magnesium and its alloys were superior to titanium and its alloys in promoting new bone formation. In addition, the unique biodegradability made magnesium and its alloys an orthopedic implant with significant therapeutic potential. However, whether the degradation rate of magnesium and its alloy can match the rate of bone-tendon integration, and whether the bioconjugation of bone-tendon after degradation can meet the exercise load still needs to be explored in further detail. Simultaneously, it is necessary for future research to improve and standardize experimental design, result measurement, etc., so as to minimize the risk of transforming animal experimental results into clinical practice.

Feasibility of Electromagnetic Knee Imaging Verified on ex-vivo Pig Knees

OBJECTIVE

The potential of electromagnetic (EM) knee imaging system verified on ex-vivo pig knee joint as an essential step before clinical trials is demonstrated. The system, which includes an antenna array of eight printed biconical elements operating at the band 0.7-2.2 GHz, is portable and cost-effective. Importantly, it can provide daily monitoring and onsite real-time examinations imaging tool for knee injuries.

METHODS

Six healthy hind legs from three dead adult pigs were removed at the hip and suspended in the developed system. For each pig, the right- and left-knee were scanning sequentially. Then ligament tear was emulated by injecting distilled water into the left knee joint of each pig for early (5 mL water) and mid-stage (10 mL water) injuries. The injured left knees were re-scanned. A modified multi-static fast delay, multiply and sum algorithm (MS-FDMAS) is used to reconstruct imaging of the knee. All knees connective tissues, such as anterior and posterior cruciate ligaments (ACL, PCL), lateral and medial collateral ligaments (LCL, MCL), tendons, and meniscus, are extracted from a healthy hind leg along with collected synovial fluid. The extracted tissues and fluid were characterized and modelled as their data are not available in the literature, then imported to build an equivalent model for pig knee of 1 mm3 resolution in a realistic simulation environment.

RESULTS

The obtained results proved potential of the proposed system to detect ligament/tendon tears.

CONCLUSION

The proposed system has the potential to detect early knee injuries in a realistic environment.

SIGNIFICANCE

Contactless EM knee imaging system verified on ex-vivo pig joints confirms its potential to reconstruct knee images. This work lays the groundwork for clinical EM system for detecting and monitoring knee injuries.

Influence of Patient Demographics and Surgical Characteristics on Pass Rates of Return-to-Activity Tests in Anterior Cruciate Ligament-Reconstructed Patients Before Physician Clearance

OBJECTIVE

To identify the frequency of passing return-to-activity tests after anterior cruciate ligament reconstruction (ACLR) and to investigate the influence of patient-specific factors on pass rates. We hypothesized that isolated strength tests would be most difficult to pass and that graft type would be the most influential factor.

DESIGN

Cross-sectional.

SETTING

Laboratory.

PARTICIPANTS

Eighty patients with a history of primary, unilateral ACLR, and 80 healthy controls participated.

INTERVENTIONS

Bilateral isokinetic strength, isometric strength, and single-leg hop tests were recorded during a single visit. The International Knee Documentation Committee (IKDC) Subjective Knee Evaluation measured subjective knee function, and the Tegner Activity Scale measured physical activity level.

MAIN OUTCOME MEASURES

Pass rates were calculated for 3 thresholds of absolute between-limb asymmetry: 0% to 10%, 11% to 15%, and 16% to 20%. Pass rates were compared by sex (male and female), graft type (patellar and hamstrings), meniscal procedure (yes and no), physical activity level (</≥ median Tegner), and time from surgery (</≥ 6 months).

RESULTS

Isokinetic quadriceps strength was consistently most difficult to pass, whereas the 6-meter timed hop and crossover hop tests were easiest. Graft type had the greatest influence on pass rates (isometric quadriceps and hamstring strength, hamstrings-to-quadriceps ratio), followed by time from surgery (6-meter timed hop and crossover hop), physical activity (IKDC), and meniscal procedure (6-meter timed hop).

CONCLUSIONS

Isokinetic quadriceps strength was the most difficult test to pass, and single-leg hop tests were the easiest. Patient-specific factors including graft type, time from surgery, physical activity level, and meniscal procedure may influence the ability to meet return-to-activity criterion after ACLR.

ACL Study Group survey reveals the evolution of anterior cruciate ligament reconstruction graft choice over the past three decades

PURPOSE

Anterior cruciate ligament reconstruction (ACLR) aims to restore knee function and stability, allowing patients to return to the activities they enjoy and minimize further injury to the meniscus and cartilage and their ultimate progression to osteoarthritis. This study aims to present the evolution of graft choice over the last three decades according to members of the ACL Study Group (SG).

METHODS

Prior to the January 2020 ACL SG biannual meeting, a survey was administered consisting of 87 questions and 16 categories, including ACLR graft choice. A similar questionnaire has been administered prior to each meeting and survey results from the past 14 meetings (1992 through 2020, excluding 1994) are included in this work. Survey responses are reported as frequencies in percentages to quantify changes in practice over the surgery period.

RESULTS

In 1992, the most frequent graft choice for primary ACLR was bone-patellar tendon-bone (BTB) autograft, at nearly 90%. Hamstring tendon (HT) autografts have increased in popularity, currently over 50%, followed by just under 40% BTB autograft. Recently, quadriceps tendon (QT) autograft has increased in popularity since 2014.

CONCLUSION

Autograft (HT, BTB, QT) is an overwhelming favorite for primary ACLR over allograft. The preference for HT autograft increased over the study period relative to BTB autograft, with QT autograft gaining in popularity in recent years. Graft selection should be individualized for each patient and understanding the global trends in graft choice can help orthopaedic surgeons discuss graft options with their patients and determine the appropriate graft for each case.

LEVEL OF EVIDENCE

Level V, Expert Opinion.

Effect of COVID-19 Social Isolation Policies on Rehabilitation After Anterior Cruciate Ligament Reconstruction

Background:

The coronavirus 2019 (COVID-19) pandemic has had a profound impact on health care in Australia. To contain the spread of the virus, strict physical distancing and social isolation policies were implemented from late March 2020. This presented a situation in which patients recovering from anterior cruciate ligament (ACL) reconstruction had limited access to face-to-face supervised rehabilitation and rehabilitation facilities.

Purpose:

To explore the impact of social distancing and isolation policies on postoperative rehabilitation in patients after ACL reconstruction.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Patients who had ACL reconstruction from October 2019 until the end of March 2020 (6 months before the implementation of COVID-19 restrictions) completed an online self-report questionnaire containing 5 sections: utilization of health care professionals for rehabilitation, frequency of rehabilitation, patient concerns and attitude, perceived impact on recovery, and changes to employment status. We compared the responses of patients who had surgery in 2019 with those who had surgery in 2020. Statistical analysis was performed using frequency statistics and central tendency measures.

Results:

A total of 185 patients (97 men, 88 women) completed the survey, for a 73% response rate. Patients had a mean age of 28 years (range, 13-57 years) and had undergone surgery a mean 4.5 months prior (range, 1.5-8 months). Most patients (80%) maintained face-to-face rehabilitation, predominantly with a physical therapist, regardless of whether their surgery took place in 2019 or 2020; rehabilitation with active, supervised exercises was most common. Almost all patients were performing strengthening exercises (164/185), and most were performing range-of-motion (139/185) and aerobic (123/185) activities at their homes. Patients were minimally concerned about access to supervised rehabilitation and knee reinjury, but they were concerned about access to equipment. Because of COVID-19, 30% were working from home; 17% were on reduced hours and 8% on increased hours; 15% were on leave or unemployed; and 30% reported no change in employment status.

Conclusion:

Patients who had undergone ACL reconstruction just before or during the first few months of the COVID-19 pandemic were able to maintain in-person contact with their health professionals during rehabilitation, and they had a positive outlook and managed well despite the restrictions.

Current perspectives of New Zealand physiotherapists on rehabilitation and return to sport following anterior cruciate ligament reconstruction: A survey

OBJECTIVE

To investigate the clinical beliefs and practices of New Zealand physiotherapists regarding pre- and post-surgical rehabilitation and return to sport (RTS) criteria following anterior cruciate ligament reconstruction (ACLR).

DESIGN

Online cross-sectional survey.

METHODS

A survey was adapted from a previously published survey and disseminated to New Zealand physiotherapists who were considered more likely to be involved in post-ACLR rehabilitation.

RESULTS

The number of completed surveys was 318. Most physiotherapists (85%) preferred to first consult patients within 14 days of ACLR. In the first six weeks following ACLR, 89% of physiotherapists see patients at least once per week. Between 3- and 6-months post-ACLR, 76% of physiotherapists see patients at least once a fortnight. Pre-operative rehabilitation and post-operative rehabilitation exceeding six months are considered essential or important to patient outcomes by over 95% of physiotherapists. While 63% of physiotherapists support RTS 9-12 months after ACLR, 11% permit RTS within 6-9 months of surgery. Common RTS considerations include functional capacity, movement quality during functional tasks, time from ACLR, and knee strength.

CONCLUSION

The survey revealed variability in the beliefs and practices of NZ physiotherapists regarding post-ACLR rehabilitation, and these beliefs and practices are at times inconsistent with best practice recommendations.

Effects of Pubertal Maturation on ACL Forces During a Landing Task in Females

BACKGROUND

Rates of anterior cruciate ligament (ACL) rupture in young people have increased by >70% over the past two decades. Adolescent and young adult females are at higher risk of ACL injury as compared with their prepubertal counterparts.

PURPOSE

To determine ACL loading during a standardized drop-land-lateral jump in females at different stages of pubertal maturation.

STUDY DESIGN

Controlled laboratory study.

METHODS

On the basis of the Tanner classification system, 19 pre-, 19 early-/mid-, and 24 late-/postpubertal females performed a standardized drop-land-lateral jump while 3-dimensional body motion, ground-reaction forces, and surface electromyography data were acquired. These data were used to model external biomechanics, lower limb muscle forces, and knee contact forces, which were subsequently used in a validated computational model to estimate ACL loading. Statistical parametric mapping analysis of variance was used to compare ACL force and its causal contributors among the 3 pubertal maturation groups during stance phase of the task.

RESULTS

When compared with pre- and early-/midpubertal females, late-/postpubertal females had significantly higher ACL force with mean differences of 471 and 356 N during the first 30% and 48% to 85% of stance, and 343 and 274 N during the first 24% and 59% to 81% of stance, respectively, which overlapped peaks in ACL force. At the point of peak ACL force, contributions from sagittal and transverse plane loading mechanisms to ACL force were higher in late-/postpubertal compared with pre- and early-/midpubertal groups (medium effect sizes from 0.44 to 0.77). No differences were found between pre- and early-/midpubertal groups in ACL force or its contributors.

CONCLUSION

The highest ACL forces were observed in late-/postpubertal females, consistent with recently reported rises of ACL injury rates in females aged 15 to 19 years. It is important to quantify ACL force and its contributors during dynamic tasks to advance our understanding of the loading mechanism and thereby provide guidance to injury prevention.

CLINICAL RELEVANCE

Growth of ACL volume plateaus around 10 years of age, before pubertal maturation, meaning that a late-/postpubertal female could have an ACL of similar size to their less mature counterparts. However, late-/postpubertal females have higher body mass requiring higher muscle forces to accelerate the body during dynamic tasks, which may increase ACL loading. Thus, if greater forces develop in these females, in part because of their increased body mass, these higher forces will be applied to an ACL that is not proportionally larger. This may partially explain the higher rates of ACL injury in late-/postpubertal females.

A THEORETICAL BASED PHYSIOTHERAPY GOAL SETTING MODEL FOR ANTERIOR CRUCIATE LIGAMENT REHABILITATION

BACKGROUND

Anterior Cruciate Ligament rehabilitation is a lengthy process and requires appropriate goal setting strategies to help optimize patient and athlete outcomes. From a global perspective, ACL injury incidences are continuing to rise, with Australia and the USA having one of the highest incidences of ACL injury rates in the athletic population. In addition, physiotherapists are expected by their professional regulatory body to effectively use goal setting practices.

DESIGN

Theoretical Goal Setting Model consisting of three phases: 1) Pre goal setting phase (empower); 2) goal implementation phase (strive); and 3) goal evaluation phase (attain).

DISCUSSION

This model provides physiotherapists with a useful process so that key aspects of setting goals are considered and incoporporated. This model showcases a necessary path a physiotherapist and patient must journey together in order to enhance rehabilitation outcomes. This model will also advance the  physiotherapists' awareness of the multi-stages of the patients goal desires, intentions and commitment to their rehabilitation.

CONCLUSION

This model is a preliminary attempt to guide both practice, teaching, and research to ensure that goal setting practices in ACL rehabilitation are given an appropriate rehabilitative platform. The next stage is to empirically validate the practical application of the model and how each phase manifests.

Do ACL Injury Risk Reduction Exercises Reflect Common Injury Mechanisms? A Scoping Review of Injury Prevention Programs

CONTEXT

Anterior cruciate ligament (ACL) injury risk reduction programs have become increasingly popular. As ACL injuries continue to reflect high incidence rates, the continued optimization of current risk reduction programs, and the exercises contained within them, is warranted. The exercises must evolve to align with new etiology data, but there is concern that the exercises do not fully reflect the complexity of ACL injury mechanisms. It was outside the scope of this review to address each possible inciting event, rather the effort was directed at the elements more closely associated with the end point of movement during the injury mechanism.

OBJECTIVE

To examine if exercises designed to reduce the risk of ACL injury reflect key injury mechanisms: multiplanar movement, single limb stance, trunk and hip dissociative control, and a flight phase.

DATA SOURCES

A systematic search was performed using PubMed, Medline, EBSCO (CINAHL), SPORTSDiscus, and PEDro databases.

STUDY SELECTION

Eligibility criteria were as follows: (1) randomized controlled trials or prospective cohort studies, (2) male and/or female participants of any age, (3) exercises were targeted interventions to prevent ACL/knee injuries, and (4) individual exercises were listed and adequately detailed and excluded if program was unable to be replicated clinically.

STUDY DESIGN

Scoping review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

A total of 35 studies were included, and 1019 exercises were extracted for analysis.

RESULTS

The average Consensus on Exercise Reporting Template score was 11 (range, 0-14). The majority of exercises involved bilateral weightbearing (n = 418 of 1019; 41.0%), followed by single limb (n = 345 of 1019; 33.9%) and nonweightbearing (n = 256 of 1019; 25.1%). Only 20% of exercises incorporated more than 1 plane of movement, and the majority of exercises had sagittal plane dominance. Although 50% of exercises incorporated a flight phase, only half of these also involved single-leg weightbearing. Just 16% of exercises incorporated trunk and hip dissociation, and these were rarely combined with other key exercise elements. Only 13% of exercises challenged more than 2 key elements, and only 1% incorporated all 4 elements (multiplanar movements, single limb stance, trunk and hip dissociation, flight phase) simultaneously.

CONCLUSION

Many risk reduction exercises do not reflect the task-specific elements identified within ACL injury mechanisms. Addressing the underrepresentation of key elements (eg, trunk and hip dissociation, multiplanar movements) may optimize risk reduction in future trials.

Is resistance training intensity adequately prescribed to meet the demands of returning to sport following anterior cruciate ligament repair? A systematic review

Objective

To identify, critique and synthesise the research findings that evaluate the use of resistance training (RT) programmes on return to sport outcome measures for people following ACL repair (ACLR).

Design and data sources

This systematic review included a comprehensive search of electronic databases (EBSCO health databases (CINAHL, MEDLINE, SPORTDiscus), Scopus and Pedro) performed in June 2020 and was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Studies were appraised using the Downs and Black checklist.

Eligibility criteria

Randomised and non-randomised controlled trials, longitudinal cohort studies and case series were considered for inclusion where an adequate description of the RT intervention was provided as a part of the study's ACLR rehabilitation protocol. Articles that did not include outcome measures related to return to sport criteria were excluded.

Results

Eleven articles met the inclusion criteria and were subjected to appraisal and data extraction. Study quality ranged from poor to excellent. RT intensity varied considerably among studies (between 5% and >80% of one repetition maximum). Only one identified study specifically investigated the effect of a low-intensity versus high-intensity RT protocol. The majority of studies reported participant outcomes that would not meet commonly used return to sport criteria.

Conclusion

There appears to be considerable variation in the intensity of RT prescribed in research for people following ACLR. Furthermore, in most of the identified studies, RT protocols promoted muscle endurance and hypertrophy without progressing to strength or power-based RT. The findings of this review provide insight into potential factors limiting returning to sport and contributing to reinjury for people following ACLR.

What did the ankle say to the knee? Estimating knee dynamics during landing - A systematic review and meta-analysis

BACKGROUND

Landing-based measures of the knee are often used to assess risk of anterior cruciate ligament (ACL) injury and inform prevention strategies. There is less understanding of the ankle's influence on knee measures during landing.

OBJECTIVE

1. Examine interactions of dynamic ankle measures alongside various subject and task characteristics on knee dynamics in vertical landing and 2. Determine whether ankle measures alone can estimate dynamic knee measures associated with ACL injury risk.

DESIGN

Systematic review and meta-analysis.

METHODS

Electronic databases Medline, EMBASE, CINAHL, Web of Science and Cochrane were screened for studies that included measurement of initial contact angles and internal joint moments of both the ankle and knee during landing in uninjured individuals.

RESULTS

28 studies were included for analysis. Using 1144 landing trials from 859 individuals, RRelief F algorithm ranked dynamic ankle measures more important than landing task and subject characteristics in estimating knee dynamics. An adaptive boosting model using four dynamic ankle measures accurately estimated knee extension (R² = 0.738, RMSE = 3.65) and knee abduction (R² = 0.999, RMSE = 0.06) at initial contact and peak knee extension moment (R² = 0.988, RMSE = 0.13) and peak knee adduction moment (R² = 1, RMSE = 0.00).

CONCLUSIONS

Dynamic ankle measures can accurately estimate initial contact angles and peak moments of the knee in vertical landing, regardless of landing task or individual subject characteristics. This study provides a theoretical basis for the importance of the ankle in ACL injury prevention.

Prognostic Factors for Patient-Reported Outcomes at 32 to 37 Years After Surgical or Nonsurgical Management of Anterior Cruciate Ligament Injury

Background:

Knowledge to inform the identification of individuals with a poor long-term prognosis after anterior cruciate ligament (ACL) injury is limited. Identifying prognostic factors for long-term outcomes after ACL injury may inform targeted interventions to improve outcomes for those with a poor long-term prognosis.

Purpose:

To determine whether ACL treatment (early augmented or nonaugmented ACL repair plus rehabilitation, rehabilitation alone, or rehabilitation plus delayed ACL reconstruction [ACLR]) and 4-year measures (quadriceps and hamstrings strength, single-leg hop, knee laxity, flexion and extension deficit, self-reported knee function, activity level) are prognostic factors for patient-reported outcomes at 32 to 37 years after acute ACL injury.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 251 patients aged 15 to 40 years with acute ACL rupture between 1980 and 1985 were allocated to early ACL repair (augmented or nonaugmented) plus rehabilitation or to rehabilitation alone, based on birth year. One hundred ninety of 234 completed 32- to 37-year follow-up questionnaires (response rate, 81%); 18 people were excluded, resulting in 172 patients available for analysis (mean age, 59 ± 6 years; 28% female). Potential prognostic factors assessed 4 years after ACL injury were ACL treatment (early ACL repair, rehabilitation alone, or delayed ACLR), isokinetic quadriceps and hamstrings strength, single-leg hop performance, knee flexion and extension deficit, knee laxity, Tegner activity scale, and Lysholm score. Outcomes included Knee injury and Osteoarthritis Outcome Score (KOOS) subscales and the Anterior Cruciate Ligament Quality of Life (ACL-QOL) measure. Linear regression adjusted for age, sex, baseline meniscal injury, and contralateral ACL injury was used to assess potential prognostic factors for 32- to 37-year outcomes. Multiple imputation accounted for missing data.

Results:

A fair/poor Lysholm score (vs excellent/good) at 4 years was a prognostic factor for worse KOOS Pain (adjusted regression coefficient, −12 [95% confidence interval (CI), −19 to −4]), KOOS Symptoms (−15 [95% CI, −23 to −7]), KOOS Sport and Recreation (−19 [95% CI, −31 to −8]), and ACL QOL (−9 [95% CI, −18 to −1]) scores. A 4-year single-leg hop limb symmetry index <90% was a prognostic factor for worse KOOS Pain (adjusted regression coefficient, −9 [95% CI, −17 to −1]) and ACL QOL (−13 [95% CI, −22 to −3]) scores at long-term follow-up. A lower activity level, delayed ACLR, and increased knee laxity were prognostic factors in the crude analysis. Rehabilitation alone versus early repair, quadriceps and hamstring strength, and flexion and extension deficit were not related to 32- to 37-year outcomes.

Conclusion:

Reduced self-reported knee function and single-leg hop performance 4 years after ACL injury were prognostic factors for worse 32- to 37-year outcomes. Estimates exceeded clinically important thresholds, highlighting the importance of assessing these constructs when managing individuals with ACL injuries.

Registration:

NCT03182647 (ClinicalTrials.gov identifier).

Immediate and 6-week effects of wearing a knee sleeve following anterior cruciate ligament reconstruction: a cross-over laboratory and randomised clinical trial

BACKGROUND

Rehabilitation following anterior cruciate ligament (ACL) reconstructions is based mainly on comprehensive progressive exercise programmes using a multi-dimensional approach. Elastic knee sleeves may be useful adjuncts to rehabilitation. The aim of this study was to determine the immediate and 6-week effects of wearing a knee sleeve on person-reported outcomes and function in participants who had undergone an ACL reconstruction and who had residual self-reported functional limitations.

METHODS

Individuals with ACL reconstruction in the previous 6 months to 5 years were recruited. Immediate effects of a commercially-available elastic knee sleeve on single-leg horizontal hop distance were explored using a cross-over design. Following this first session, participants were randomised into a Control Group and a Sleeve Group who wore the sleeve for 6 weeks, at least 1 h daily. Outcome measures for the randomised clinical trial (RCT) were the International Knee Documentation Classification Subjective Knee Form (IKDC-SKF) score, the single-leg horizontal hop distance, and isokinetic quadriceps and hamstring peak torque. Linear mixed models were used to determine random effects. Where both limbs were measured at multiple time points, a random measurement occasion effect nested within participant was used.

RESULTS

Thirty-four individuals (16 women) with ACL reconstruction completed the cross-over trial. Hop distance for the injured side during the sleeve condition increased by 3.6 % (95 % CI 0.4-6.8 %, p = 0.025). There was no evidence of differential changes between groups for the IKDC-SKF (Sleeve Group n = 15; Control Group n = 16; p = 0.327), or relative improvement in the injured side compared to the uninjured side for the physical performance measures (Sleeve Group n = 12, Control Group n = 12; three-way interaction p = 0.533 [hop distance], 0.381 [quadriceps isokinetic peak torque], and 0.592 [hamstring isokinetic peak torque]).

CONCLUSIONS

Single-leg hop distance of the ACL reconstructed side improved when wearing a knee sleeve. Wearing the knee sleeve over 6 weeks did not lead to enhanced improvements in self-reported knee function, hop distance and thigh muscle strength compared to the control group.

TRIAL REGISTRATION

The trial was prospectively registered with the Australia New Zealand Clinical Trials Registry No: ACTRN12618001083280 , 28 June 2018.

ACL Study Group presents the global trends in ACL reconstruction: biennial survey of the ACL Study Group

OBJECTIVES

The primary objective of this survey was to gauge the current global trends in anterior cruciate ligament reconstruction (ACLR) as reported by the members of the Anterior Cruciate Ligament (ACL) Study Group (SG).

METHODS

A survey was created and distributed among the members of the ACL SG consisting of 87 questions and 16 categories related to ACLR, including member demographics, preoperative management, primary ACLR techniques and graft choice, use of concomitant procedures and biological augmentation, postoperative rehabilitation, and more.

RESULTS

The survey was completed by the 140 members of the ACL SG. Fifty per cent of members are from Europe, 29% from the USA, 15% from the Asia-Pacific and the remaining 6% are from Latin America, the Middle East, New Zealand and Africa. Most (92%) do not believe there is a role for non-operative management of ACL tears in higher level athletes; conversely, most agree there is a role for non-operative management in lower impact athletes (92%). A single-bundle (90%) technique with hamstring autograft (53%) were most common for primary ACLR. Tunnel position varied among respondents. Sixty-one per cent do not use allograft for primary ACLR. Fifty per cent of respondents use cortical suspensory fixation on the femur, with variable responses on the tibia. Most (79%) do not use biologics in primary ACLR, while 83% think there is a selective role for extra-articular augmentation in primary ACLR. Fifty per cent prefer bone-tendon-bone autograft for revision ACLR and extra-articular augmentation is more commonly used (13% always, 26% often) than in primary ACLR (0% always, 15% often). A majority (53%) use a brace after primary ACLR. The most common responses for minimal time to return to play after primary ACLR were 6-8 months (44%) and 8-12 months (41%).

CONCLUSION

We presented the thoughts and preferences of the ACL SG on the management of ACL injuries. This survey will help to facilitate an ongoing discussion with regard to ACLR by providing global insights into the current surgical trends in ACLR.

LEVEL OF EVIDENCE

Level V, Expert Opinion.

Risk Factors for Requiring a Revision Anterior Cruciate Ligament Reconstruction: A Case-Control Study

Anterior cruciate ligament (ACL) reconstruction is considered as a successful orthopaedic procedure that attempts to help patients return to their preinjury level of activity. However, some patients may need to undergo revision surgery, and this potentially may be associated with certain surgery-specific or patient risk factors. Therefore, the purpose of this study was to assess the potential role of (1) demographics, (2) family history, (3) graft choice, (4) sport, and (5) mechanism of injury (contact vs. noncontact) in the risk for needing a revision ACL for improved clinical outcomes. All patients who had undergone a primary ACL reconstruction between 2012 and 2016 were identified from at a single institution. About 312 patients who had a mean age of 24 years (range, 9-62 years) and a mean follow-up of 4 years (range, 1-10). Patients were further evaluated to identify those who had a revision. There were 19 patients (6.1%) with a mean age of 22 years (range, 13-38 years) and a mean follow-up of 5 years (range, 1-10) that required a revision reconstruction. Gender ratios (p = 0.56) and mean age (p = 0.44) were similar among the cohorts. Family history of ACL reconstruction had no association with revision risk (p = 0.57). Those with tibialis anterior allografts (37 vs. 4%; p = 0.0001) and hamstring allografts (16 vs. 1%; p = 0.0001) were far more likely to undergo a revision. Bone-tendon-bone (BTB) patella autografts were less likely (26 vs. 73%; p = 0.0001). Sport did not play a role in revision with those injured playing basketball (p = 0.61), football (p = 0.52), lacrosse (p = 0.52), soccer (p = 0.83), and volleyball (p = 0.61). There were a greater percentage of contact injuries that required revision (95 vs. 77%; p = 0.07). Graft selection played a significant role in requiring revision surgery with allografts portending to higher revision rates and BTB patella autografts conferring a lower risk.

Preliminary experience of an international orthopaedic registry: the ESSKA Paediatric Anterior Cruciate Ligament Initiative (PAMI) registry

Paediatric and adolescent ACL injuries are an emerging health burden, increasing at a higher rate than in adults. They compromise quality of life, affect knee structure and function, lead to the early development of osteoarthritis and are a serious economic burden due to shortened professional careers and subsequent surgeries. Up to 35% of children and adolescents will experience a second ACL injury and this population particularly at high risk of secondary intraarticular soft tissue degeneration and growth abnormalities. However, there is still a lack of high-quality outcome studies on this specific population and many knowledge gaps persist in the current treatment guidelines. It is currently unknown whether ACL reconstruction in this young population decreases the risk of irreversible secondary intraarticular soft tissue degeneration. Furthermore, it is not known whether return to high or elite level sports after paediatric ACL injury or reconstruction should be recommended. The relatively low number of paediatric ACL injuries seen in each hospital makes it necessary to conduct international multi-centre studies to collect robust data to provide evidence-based guidelines for the treatment of these injuries. The Paediatric Anterior Cruciate Ligament Initiative (PAMI) was thus started by the European Society of Sports Traumatology, Knee Surgery & Arthroscopy and opened for patient inclusion in 2018. This comprehensive overview of the first 2 years of the PAMI registry shows that the project is now well consolidated and accepted by the European orthopaedic community. Future challenges include ensuring additional external funding to ascertain long term sustainability and continuous dissemination of the knowledge acquired in scientific journals.

Lower limb kinematics differ at the time of foot contact between successful and unsuccessful single limb landings following anterior cruciate ligament reconstruction

OBJECTIVES

To investigate differences in lower extremity kinematics at initial ground contact between successful and unsuccessful single limb landings following anterior cruciate ligament (ACL) reconstruction.

DESIGN

Observational study.

SETTING

Controlled laboratory environment.

PARTICIPANTS

22 male participants (aged 17-40 years) who had undergone unilateral ACL reconstruction attended a single test session.

MAIN OUTCOME MEASURES

Within-subjects comparisons was performed for pelvis, hip, knee and ankle kinematics using paired t-tests.

RESULTS

When unsuccessful at landing on the ACL reconstructed limb, participants had significantly increased knee flexion (P = 0.04) and reduced ankle plantarflexion (P = 0.03) compared to their successful landings. In contrast, when unsuccessful at landing on the unaffected limb, participants had significantly increased pelvic contralateral hitch (P < 0.01) and increased hip abduction (P < 0.01) compared to successful landings.

CONCLUSION

Body position at the time of initial contact was different for landings that were successful compared to landings that were unsuccessful. These differences were limb-specific: altered position in sagittal plane preceded unsuccessful landings on the reconstructed limb whereas altered position in the coronal plane body position that preceded unsuccessful landings on the unaffected limb. These findings suggest that limb specific landing strategies may be required to improve athletes' performance following ACL reconstruction.

LEVEL OF EVIDENCE

IV.

Textile Electromagnetic Brace for Knee Imaging

A wearable textile brace is introduced as an electromagnetic imaging system that breaks hospital boundaries to real-time onsite scanning for knee injuries. The proposed brace consists of a 12-element textile slot loop antenna array, which is designed to match the human knee for enhanced electromagnetic wave penetration. Wool felt and conductive fabric are used to fabricate the antenna array thanks to their flexibility and proper dielectric properties. Each antenna element has a compact footprint of 42 ×24 ×3.22 mm³ and achieves unidirectional radiation, high front-to-back ratio of 14 dB, wide bandwidth of 81% at 0.7-1.7 GHz, and safe SAR levels. A modified double-stage delay, multiply, and sum (DS-DMAS) algorithm is used to process the collected signals from the antenna array based on differential left/right knee imaging. The reconstructed images numerically and experimentally on realistic phantoms demonstrate the potential of the brace system for onsite detection of different types of ligaments/tendon tears.

Mechanism of Anterior Cruciate Ligament Loading during Dynamic Motor Tasks

INTRODUCTION

This study determined anterior cruciate ligament (ACL) force and its contributors during a standardized drop-land-lateral jump task using a validated computational model.

METHODS

Three-dimensional whole-body kinematics, ground reaction forces, and muscle activation patterns from eight knee-spanning muscles were collected during dynamic tasks performed by healthy recreationally active females (n = 24). These data were used in a combined neuromusculoskeletal and ACL force model to determine lower limb muscle and ACL forces.

RESULTS

Peak ACL force (2.3 ± 0.5 bodyweight) was observed at ~14% of stance during the drop-land-lateral jump. The ACL force was primarily generated through the sagittal plane, and muscle was the dominant source of ACL loading. The main ACL antagonists (i.e., loaders) were the gastrocnemii and quadriceps, whereas the hamstrings were the main ACL agonists (i.e., supporters).

CONCLUSION

Combining neuromusculoskeletal and ACL force models, the roles of muscle in ACL loading and support were determined during a challenging motor task. Results highlighted the importance of the gastrocnemius in ACL loading, which could be considered more prominently in ACL injury prevention and rehabilitation programs.

Implementation of an injury prevention programme in community netball: An observational study

The Netball KNEE programme is a freely available, netball-specific injury prevention programme promoted to netball coaches. However, little is known about its implementation. This cross-sectional study aimed to evaluate the implementation of the Netball KNEE programme in community netball, and determine if implementation differed by player age. Four netball clubs participated. Training sessions (n = 67) were observed to determine if coaches used Netball KNEE programme activities as intended, modified or not at all during training, and whether feedback on technique was provided. No team performed the recommended number of activities without modification. On average, only 12%, 18% and 14% of the recommended number of activities were performed as intended in the 7-10, 11-13 and ≥14 years age groups, respectively. Warm-up/footwork activities (30%; 0-80%) were more frequently performed than strength (0%; 0-50%), balance/landing (0%; 0-50%), and agility (0%; 0-25%) activities (p < 0.001). Feedback was required in 65% of activities, but frequently not provided (56%). Netball KNEE programme implementation is low in community netball, particularly strength, balance/landing and agility activities. This finding, and lack of provision of feedback on technique, is concerning as improving movement patterns is a key aim of injury prevention programmes.

Editorial Commentary: Is It Time for the Vancomycin Wrap to Become a Universal Recommendation for the Prevention of Septic Arthritis Following Anterior Cruciate Ligament Reconstruction?

Septic arthritis is a devastating complication of anterior cruciate ligament (ACL) reconstruction, which can still occur in approximately 1% of patients despite appropriate intravenous antibiotic prophylaxis and other recommended preventative measures being undertaken. The infection is most likely secondary to the autograft becoming contaminated during harvest and preparation, introducing bacteria into the joint on insertion. Presoaking ACL grafts in 5 mg/mL vancomycin is a novel method developed to eradicate this bacterial contamination and is supported by compelling Level III evidence from multiple observational trials showing a dramatic reduction in infection rates without any evidence of increased graft failure. As such, it is time for this technique to become a universal recommendation? That said, as observational studies using a historical cohort as a comparator are at risk of various biases, Level I evidence is ultimately required for infection prophylaxis methods to be recognized as a universal recommendation in infection control guidelines. Consequently, future research endeavors on the "vancomycin wrap" should focus on randomized controlled trials, possibly nested within ACL registries.

Sex and mechanism of injury influence knee joint loading symmetry during gait 6 months after ACLR

Early-onset knee osteoarthritis (OA) is associated with gait asymmetries after anterior cruciate ligament reconstruction (ACLR). Women have higher risks of sustaining non-contact injuries, and are more likely to present with aberrant movement patterns associated with the mechanism of injury (MOI). We hypothesized that sex and MOI would influence gait after ACLR. Seventy participants, grouped by sex and MOI, completed biomechanical testing during over-ground walking when they had full knee range of motion, trace or less knee effusion, greater than 80% quadriceps strength limb symmetry index, ability to hop on each leg without pain, and initiated running. Bilateral knee kinetics, kinematics, and joint contact forces were compared using mixed-model analysis of variance (α = .05). There was a three-way interaction effect of sex × MOI × limb for peak medial compartment contact force (P = .002), our primary outcome measure previously associated with OA development. Men with non-contact injuries walked with asymmetry characterized by underloading of the involved limb. Men with contact injuries walked with the most symmetrical loading. In women, no clear pattern emerged based on MOI. Targeting, and possibly prioritizing interventions for athletes who present with gait asymmetries after ACLR based on sex and MOI, may be necessary to optimize outcomes. Statement of Clinical Significance: Sex and MOI may influence walking mechanics, and could be considered in future interventions to target gait symmetry, as a response to interventions may vary based on differences in sex and MOI.

Intensive supervised rehabilitation versus less supervised rehabilitation following anterior cruciate ligament reconstruction? A systematic review and meta-analysis

OBJECTIVES

To investigate whether intensive supervised rehabilitation following ACL reconstruction leads to superior self-reported function and sports participation compared to less supervised rehabilitation.

DESIGN

Systematic review and meta-analysis.

METHODS

We included randomised controlled trials (RCTs) comparing supervised rehabilitation to rehabilitation with a similar protocol that used less supervised sessions for athletes following ACL reconstruction. Two reviewers independently screened studies and extracted data. The Physiotherapy Evidence Database (PEDro) scale was used to evaluate methodological quality and GRADE to evaluate overall quality of evidence. Self-reported function and sports participation were the primary outcomes. Data were pooled using random effects meta-analyses.

RESULTS

Our search retrieved 4075 articles. Seven articles reporting on six RCTs were included (n=353). Very-low to low-certainty evidence suggests intensive supervised rehabilitation is not superior to less supervised rehabilitation following ACL reconstruction for improving self-reported function, sports participation, knee flexor and extensor strength, range of motion, sagittal plane knee laxity, single leg hop performance, or quality of life.

CONCLUSION

Based on uncertain evidence, intensive supervised rehabilitation is not superior to less supervised rehabilitation for athletes following ACL reconstruction. Although high-quality RCTs are needed to provide more certain evidence, clinicians should engage athletes in shared decision making to ensure athletes' rehabilitation decisions align with current evidence on supervised rehabilitation as well as their preferences and values.

Trunk, pelvis and lower limb coordination between anticipated and unanticipated sidestep cutting in females

BACKGROUND

Emerging research has suggested a plausible relationship may exist between lower limb coordination and musculoskeletal injury. A small number of studies have investigated the link between coordination and anterior cruciate ligament (ACL) injury during sidestep cutting. While prior work has shown unanticipated sidestep cutting to exhibit a more 'at risk' kinematic profile compared to anticipated tasks, a detailed understanding of the coordination between multiple joints and how they differ during unanticipated actions is lacking, particularly in females.

RESEARCH QUESTION

The purpose of this study was to observe the difference in trunk, pelvis and lower limb coordination and coordination variability during a dynamic, sidestep cutting task under anticipated and unanticipated conditions in a healthy female cohort.

METHODS

Three-dimensional motion analysis data were recorded during anticipated and unanticipated sidestep cutting for nineteen healthy female participants (age, 24 ± 3yrs; height, 164 ± 5 cm; and weight, 58 ± 6 kg). Vector coding methodology was used to calculate coordination and coordination variability values and statistical parametric and non-parametric mapping was used to comprehensively determine differences between anticipated and unanticipated conditions.

RESULTS

Differences were observed between anticipated and unanticipated conditions in the hip flexion - knee abduction angle (89 % of stance), hip rotation - knee abduction angle (55 % of stance), knee flexion - knee abduction angle (81-83 %, 86 % and 88-89 %) and knee flexion - ankle flexion angle (14-18 %) coupling angles. Differences in coupling angle variability were also observed with only one cluster of significance seen in hip abduction - knee abduction variability (27-30 % of stance).

SIGNIFICANCE

Healthy females exhibit significant differences in lower limb coupling angles and coupling angle variability between anticipated and unanticipated sidestep cutting. Interventions aimed at reducing ACL injury risk may need to consider that anticipated and unanticipated sidestep cutting tasks present unique demands, and therefore should both be trained specifically.

Knee Injury and Osteoarthritis Outcome Score (KOOS) Responder Criteria and Minimal Detectable Change 3-12 Years Following a Youth Sport-Related Knee Injury

The applicability of thresholds that constitute an acceptable score or meaningful change on the Knee injury and Osteoarthritis Outcome Score (KOOS) in cohorts ≥ 5 years following knee injury is not well understood. The primary objective of this study was to evaluate the association between intra-articular knee injury type and two different KOOS pain thresholds (patient acceptable symptom state (PASS) and Englund symptomatic knee criteria) in the Alberta Youth Prevention of Osteoarthritis (PrE-OA) cohort, which includes participants 3–12 years following a youth sport-related knee injury and uninjured controls with similar age, sex and sport characteristics. Analyses accounted for sex, time since injury and the interaction between time since injury and injury type. Secondary objectives were to report proportions meeting thresholds for KOOS outcomes and minimal detectable change (MDC) from published test–retest reliability data, over a 1–4-year follow-up. Two hundred and fifty-three (253) participants (124 injured, 129 controls) were included in analyses, of which 153 (77 injured, 76 controls) had follow-up data. Similar odds were observed for presence of pain (below PASS threshold) in participants with anterior cruciate ligament (ACL)/meniscus injury (odds ratio (OR) 4.2 (97.5% confidence interval (CI): 1.8, 9.9)) and other knee injuries (OR 4.9 (97.5% CI: 1.2, 21.0)), while there were higher odds for presence of Englund “symptomatic knee” criteria in participants with ACL/meniscus injury (OR 13.6 (97.5% CI: 2.9, 63.4)) than other knee injuries (OR 7.3 (97.5% CI: 0.8, 63.7)) compared to controls. After a median 23.4 (8 to 42) month follow-up, 35% of previously injured participants had at least one KOOS sub-scale score that worsened by more than the MDC published threshold. Despite limited research, this study shows that individuals with youth sport knee injuries other than ACL or meniscus injury may also experience significant pain and symptoms 3–12 years following injury. Replication and further follow-up are needed to identify a possible clinical trajectory towards osteoarthritis.

Distribution of Bone Contusion Patterns in Acute Noncontact Anterior Cruciate Ligament-Torn Knees

BACKGROUND

Bone contusions are commonly observed on magnetic resonance imaging (MRI) in individuals who have sustained a noncontact anterior cruciate ligament (ACL) injury. Time from injury to image acquisition affects the ability to visualize these bone contusions, as contusions resolve with time.

PURPOSE

To quantify the number of bone contusions and their locations (lateral tibial plateau [LTP], lateral femoral condyle [LFC], medial tibial plateau [MTP], and medial femoral condyle [MFC]) observed on MRI scans of noncontact ACL-injured knees acquired within 6 weeks of injury.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

We retrospectively reviewed clinic notes, operative notes, and imaging of 136 patients undergoing ACL reconstruction. The following exclusion criteria were applied: MRI scans acquired beyond 6 weeks after injury, contact ACL injury, and previous knee trauma. Fat-suppressed fast spin-echo T2-weighted MRI scans were reviewed by a blinded musculoskeletal radiologist. The number of contusions and their locations (LTP, LFC, MTP, and MFC) were recorded.

RESULTS

Contusions were observed in 135 of 136 patients. Eight patients (6%) had 1 contusion, 39 (29%) had 2, 41 (30%) had 3, and 47 (35%) had 4. The most common contusion patterns within each of these groups were 6 (75%) with LTP for 1 contusion, 29 (74%) with LTP/LFC for 2 contusions, 33 (80%) with LTP/LFC/MTP for 3 contusions, and 47 (100%) with LTP/LFC/MTP/MFC for 4 contusions. No sex differences were detected in contusion frequency in the 4 locations (P > .05). Among the participants, 50 (37%) had medial meniscal tears and 52 (38%) had lateral meniscal tears.

CONCLUSION

The most common contusion patterns observed were 4 locations (LTP/LFC/MTP/MFC) and 3 locations (LTP/LFC/MTP).

The effect of cognitive loading on the lower extremity movement coordination variability in patients with anterior cruciate ligament reconstruction

BACKGROUND

The altered coordination variability was related to anterior cruciate ligament (ACL) re-injury after ACL reconstruction (ACL-R). As motor performance is affected by the cognitive loading, understanding the interaction of cognition and coordination variability is crucial for addressing secondary injury prevention and restoring function in rehabilitation programs.

RESEARCH QUESTION

To investigate the lower extremity movement coordination variability asymmetry in individuals following ACL-R and determine the effects of cognitive loading on the coordination variability.

METHODS

Twenty-five males who received unilateral ACL-R using hamstring tendon autograft (7.4 ± 1.3 months past reconstruction). Participants performed walking without (single-task condition) and with the concurrent cognitive task (dual-task condition). The coordination variability in hip-knee coupled motion in different gait phases was calculated using vector coding technique.

RESULTS

The injured leg demonstrated greater coordination variability in hip flexion/knee flexion (HF/KF) during mid-stance phase (P = 0.012) than the uninjured leg in both conditions. No significant differences were observed in other phases of HF/KF variability or other measures in all phases between the injured and uninjured legs. Both legs increased the HF/KF coordination variability during loading response phase in dual-task condition than that in single-task condition (P < 0.001).

SIGNIFICANCE

Individuals following ACL-R demonstrated coordination variability asymmetry of sagittal plane hip-knee coupled motion. The dual cognitive task increased the coordination variability of hip flexion/knee flexion during loading response phase in individuals following ACL-R.

Lower Limb Muscle Size after Anterior Cruciate Ligament Injury: A Systematic Review and Meta-Analysis

BACKGROUND

Anterior cruciate ligament (ACL) injury is known to have a number of deleterious effects on lower limb muscle function. Alterations in muscle size are one such effect that have implications towards reductions in strength and functioning of the lower limbs. However, a comprehensive analysis of alterations in muscle size has yet to be undertaken.

OBJECTIVE

To systematically review the evidence investigating lower limb muscle size in ACL injured limbs.

DESIGN

Systematic review DATA SOURCES: Database searches of Medline, SPORTDiscus, Embase, Cinahl and Web of Science as well as citation tracking and manual reference list searching.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Individuals with ACL deficient or reconstructed limbs with an assessment of lower limb muscle size and control limb data (contralateral or uninjured control group) METHODS: Risk of bias assessment was completed on included studies. Data were extracted and where possible meta-analyses performed. Best evidence synthesis was also undertaken.

RESULTS

49 articles were included in this review, with 37 articles included in the meta-analyses. 66 separate meta-analyses were performed using various measures of lower limb muscle size. Across all measures, ACL deficient limbs showed lesser quadriceps femoris muscle size (d range = - 0.35 to - 0.40), whereas ACL reconstructed limbs showed lesser muscle size in the quadriceps femoris (d range = - 0.41 to - 0.69), vastus medialis (d = - 0.25), vastus lateralis (d = - 0.31), hamstrings (d = - 0.28), semitendinosus (d range = - 1.02 to - 1.14) and gracilis (d range = - 0.78 to - 0.99) when compared to uninjured limbs.

CONCLUSION

This review highlights the effect ACL injury has on lower limb muscle size. Regardless of whether an individual chooses a conservative or surgical approach, the quadriceps of the injured limb appear to have lesser muscle size compared to an uninjured limb. When undertaking reconstructive surgery with a semitendinosus/gracilis tendon graft, the harvested muscle shows lesser muscle size compared to the uninjured limb.

Evolution of service metrics and utilisation of objective discharge criteria in anterior cruciate ligament reconstruction rehabilitation: a retrospective cohort study with historical control in a public hospital physiotherapy department

Background

ACL reconstruction (ACLR) is a common procedure requiring rehabilitation in public hospital physiotherapy departments. The rate of re-rupture and reduced rates of return to sport following ACLR are concerning. Current guidelines recommend a progressive approach to rehabilitation based on objective criteria. The aim of this study was to determine whether a new public hospital model of care incorporating a phase-based program increased physiotherapist utilisation of objective outcome measures, improved service metrics including attendance and rehabilitation completion rates, and increased patient-reported activity and knee function.

Methods

Records from patients attending outpatient physiotherapy after ACL reconstruction (N = 132) were included in a retrospective chart review to assess utilisation of objective measures such as quadricep and hamstring strength assessment, patient attendance and rehabilitation completion. Phone followup (minimum 1 year) was conducted to retrieve patient-reported measures of knee function (IKDC) and activity (Tegner Activity Scale). Patients were categorised by rehabilitation model of care (contemporary - time based [N = 93] vs new - phase based [N = 39]) and logistic regression used to assess the influence of patient factors and model of care on outcomes.

Results

Compliance was equivalent between models of care and completion rates (formal discharge by therapist) were low (30–38%). The probability of a patient receiving objective strength assessment was associated with model of care, sex, BMI and number of sessions attended. The probability of a patient being recorded as discharged from the program was significantly associated with model of care, and duration and number of sessions.

Conclusion

Introduction of an updated model of care including a phase-based rehabilitation program increased physiotherapist utilisation of objective outcome measures in line with current ACLR rehabilitation recommendations, increased total rehabilitation duration and increased total number of sessions attended. Despite this, rehabilitation completion rates remained low, and self-reported activity and knee function remained equivalent.

Level of evidence

III, retrospective cohort study.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40945-020-00093-9.

Sex- and injury-based differences in knee biomechanics in mouse models of post-traumatic osteoarthritis

Sex and joint injury are risk factors implicated in the onset and progression of osteoarthritis (OA). In mouse models of post-traumatic OA (ptOA), the pathogenesis of disease is notably impacted by sex (often worse in males) and injury model (e.g. meniscal versus ligament injury). Increasing ptOA progression and severity is often associated with greater relative instability of the joint but few studies have directly quantified changes in joint mechanics after injury and compared outcomes across multiple models in both male and female mice. Passive anterior-posterior knee biomechanics were evaluated in 10-week-old, male and female C57BL/6J mice. PtOA injury models included destabilisation of the medial meniscus (DMM), anterior cruciate ligament transection (ACLT) or mechanical rupture (ACLR), and combined DMM and ACLT (DMM + ACLT). Sham operated and non-operated controls (NOC) were included for baseline comparisons. The test apparatus loaded hindlimbs at 60° flexion between ± 1 N at 0.5 mm/s (build specifications available for download: https://doi.org/10.17632/z754455x3c.1). Measures of joint laxity (range of motion, neutral zone) and stiffness were calculated. Joint laxity was comparable between male and female mice while joint stiffness was greater in females (P ≤ 0.002, correcting for body-mass and injury-model). Anterior-posterior joint mechanics were minimally altered by DMM but significantly affected by loss of the ACL (P < 0.001), with equivalent changes between ACL-injury models despite different injury mechanisms and adjacent meniscal damage. These findings suggest that despite the important role of joint injury; sex- and model-specific differences in ptOA progression and severity are not primarily driven by altered anterior-posterior knee biomechanics.

The Effectiveness of Nonoperative Treatment for Anterior Cruciate Ligament Rupture on Patient-Reported Outcomes and Muscular Strength: A Critically Appraised Topic

Clinical Scenario: Anterior cruciate ligament (ACL) ruptures are one of the most common injuries in young athletic populations. The leading treatment for these injuries is ACL reconstruction (ACL-r); however, nonoperative treatments are also utilized. Following ACL-r, patients experience prolonged muscle weakness and atrophy of the quadriceps muscle group, regardless of rehabilitation. Nonoperative treatment plans following ACL injury exist, but their outcomes are less familiar, in spite of providing insight as a nonsurgical "control" for postsurgical rehabilitation outcomes. Therefore, the purpose of this critically appraised topic was to evaluate quadriceps strength and function following nonoperative ACL rehabilitation using objective and subjective measures including isokinetic dynamometry, the single-leg hop test, and the International Knee Documentation Committee (IKDC) subjective knee form. Focused Clinical Question: What are the effects of nonoperative treatment on peak isokinetic knee-extensor torque, the single-leg hop tests, and the IKDC in patients who have sustained an ACL rupture? Summary of Key Findings: Patients who underwent nonsurgical ACL treatment produced limb symmetry index, with the side-to-side torque difference expressed as a percentage, and values at or above 90% for all 4 single-leg hop tests and strength tests similar to ACL-r patients. All studies showed individuals had higher IKDC scores at baseline collection when compared with patients who underwent ACL-r but showed lower IKDC scores at long-term follow-up compared with ACL-r patients. Clinical Bottom Line: Nonoperative treatments of ACL injuries yield similar long-term results in quadriceps strength as ACL-r. Due to the quality of evidence and the absence of randomized controlled trials on this topic, these outcomes should be considered with caution. Strength of Recommendation: The Oxford Centre for Evidence-Based Medicine taxonomy recommends a grade of B for level 2 evidence with consistent findings.

Limited Support for Trunk and Hip Deficits as Risk Factors for Athletic Knee Injuries: A Systematic Review With Meta-analysis and Best-Evidence Synthesis

OBJECTIVE

To determine whether neuromuscular deficits in trunk and hip-related function are risk factors for athletic knee injuries.

DESIGN

Etiology systematic review with meta-analysis.

LITERATURE SEARCH

Six online databases (MEDLINE, Web of Science, Embase, CINAHL, Scopus, and SPORTDiscus) were searched up to April 2019.

STUDY SELECTION CRITERIA

Studies assessing trunk and hip neuromuscular function as risk factors for knee injuries in healthy athletic populations were included.

DATA SYNTHESIS

Outcomes were synthesized quantitatively using meta-analysis of odds ratios, and qualitatively using best-evidence synthesis.

RESULTS

Twenty-one studies met the inclusion criteria. There was very low-certainty evidence that greater hip external rotation strength protected against knee injuries (odds ratio = 0.78; 95% confidence interval: 0.70, 0.87; P<.05). There was limited evidence that deficits in trunk proprioception and neuromuscular control, and the combination of excessive knee valgus and ipsilateral trunk angle when landing unilaterally from a jump, may be risk factors for knee injuries.

CONCLUSION

Most variables of trunk and hip function were not risk factors for injuries. Further research is required to confirm whether hip external rotation strength, trunk proprioception and neuromuscular control, and the combination of knee valgus angle and ipsilateral trunk control are risk factors for future knee injuries. J Orthop Sports Phys Ther 2020;50(9):476-489. Epub 1 Aug 2020. doi:10.2519/jospt.2020.9705.

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.