Controversies in knee rehabilitation: anterior cruciate ligament injury

Nonoperative Treatment as an Option for Isolated Anterior Cruciate Ligament Injury: A Systematic Review and Meta-analysis

Background

An anterior cruciate ligament (ACL) tear is a risk factor for early osteoarthritis (OA) onset. Generally, ACL reconstruction (ACLR) is associated with better outcomes. However, there is a lack of evidence regarding the effect of operative versus nonoperative treatment for preventing premature knee OA in isolated ACL tears while achieving good functional outcomes.

Purpose/Hypothesis

The purpose of the study was to compare the outcomes of ACLR to primarily nonoperative management of isolated ACL tears. It was hypothesized that the outcomes between treatment types would be similar.

Study Design

Systematic review; Level of evidence, 3.

Methods

This systematic review was registered on the International Prospective Register of Systematic Reviews (PROSPERO) (registration No. CRD42021285901) and was conducted according to the Cochrane Handbook guidelines. We systematically searched for randomized and nonrandomized studies that compared ACLR with nonoperative treatments in isolated ACL tears in 3 databases until October 25, 2021. The risk of bias and quality of evidence of the included studies was assessed in accordance with the Cochrane guidelines. The primary outcome was radiologic signs of OA, and the secondary outcomes were functional parameters. Using the common effects model, we calculated pooled mean differences (MDs) and odds ratios (ORs) with 95% CIs.

Results

Five studies-2 randomized controlled trials (RCTs) and 3 retrospective non-RCTs-were included. There was a moderate risk of bias in 2 studies and a serious risk of bias in 1 study. The quality of evidence was rated low because of the higher risk of bias and inconsistency. Nonoperatively treated knees showed a trend toward lower odds of developing radiological signs of OA (OR, 1.84 [95% CI, 0.90 to 3.75]); however, surgically reconstructed knees had significantly better stability (MD, -2.44 [95% CI, -3.21 to -1.66 ]) and a trend toward better but clinically not meaningful Lysholm scores (MD, 2.88 [95% CI, -1.09 to 6.85]). The qualitative synthesis showed that surgical reconstruction was protective against subsequent injuries but not superior when returning to previous activity levels or various functional tests.

Conclusion

Findings indicated that there is no certain evidence that ACLR for an isolated ACL tear is superior to nonoperative treatment. Clinicians should consider nonoperative treatments with a well-designed rehabilitative program as a primary option. However, these findings must be interpreted with caution because of low study quality and high risk of bias.

Psychosocial experiences of competitive rugby players on the "long, long journey" to recovery following ACL ruptures and reconstruction

Anterior Cruciate Ligament (ACL) injuries are serious and potentially career-ending. Reconstruction surgery and extended rehabilitation typically follow, but some athletes never attain the same level of sport performance. The psychosocial experiences of athletes who sustain ACL injuries and their cognitive appraisal, emotional and behavioral responses to the injury, and reconstruction require further attention during the different recovery phases. The aim is to explore these psychosocial experiences, social support needs and sources thereof of competitive athletes who sustained unilateral ACL ruptures and underwent reconstruction surgery. Semi-structured interviews with six competitive rugby players (M age: 22.3 ± 2.92 years), elicited information at seven time-points. We analyzed the qualitative information through thematic analysis. Five common themes emerged: (1) cognitive appraisal, (2) emotional responses (negative and positive affective responses), (3) behavioral responses, (4) social support needs and sources thereof, and (5) adversity-induced identity expansion (athletic and person-centered identities). In-vivo quotes gave a rich description of the athletes' experiences throughout the "long, long journey" to return-to-sport. These findings may sensitize and assist sports healthcare professionals, coaches, teammates, family, and friends to explore various psychosocial experiences throughout the injury and recovery period. Phase-appropriate psychosocial support or referral to sport psychology services is recommended to enhance the recovery process, improve long-term physical and mental health, and subsequent performance.

Return to active duty after anterior cruciate ligament reconstruction (ACLR) in Chinese male military aircrews

Background

Surgically treated anterior cruciate ligament (ACL) injuries may be a waivable condition and allow return to full flight status, but waivers are based on expert opinion rather than recent published data. The purpose of this study was to evaluate return to flight after anterior cruciate ligament reconstruction (ACLR) in male military aircrews with ACL injuries and to identify factors that affect flight clearance.

Method

A single-center retrospective review was conducted by the authors for all active-duty aircrew who underwent ACLR at an authorized military medical center from January 2010 to December 2019. Demographic characteristics, occupational information, surgical data, and flight readiness evaluation outcomes were collected. Based on the final medical evaluation, subjects were divided into a qualified group (N = 64) and a disqualified group (N = 9), and the difference in data collected between the two groups was then analyzed to identify factors affecting flight clearance.

Results

A total of 73 patients underwent successful ACLR with a mean age of 31.6 ± 5.6 years. Non-contact injury was the main type of ACL injury, accounting for 84.9% of the total injuries. 55 cases (75.3%) occurred during daily sports activities and 18 (24.7%) during military training. 64 of the 73 crewmembers (87.7%) were able to return to flight at their last follow-up evaluation. The preoperative interval time (PIT) was significantly less in the qualified group than in the disqualified group (P = 0.002). Patients who underwent ACLR within three months were more likely to return to flying than those who underwent the procedure three months later (97.4% vs. 76.5%, P = 0.010). The incidence of failure to return to flight duty was significantly higher in aircrews with ACL injuries combined with meniscal injuries than in aircrews with isolated ACL injuries (21.4% vs. 0.0%, P = 0.017).

Conclusion

ACLR appears to be safe for military aircrew suffering ACL injuries with or without meniscal injury, and return to flight status is the most likely outcome for the majority of postoperative pilots. Prolonged PIT, PIT > 3 months, and ACL injury combined with meniscus injury had a negative impact on postoperative flight readiness.

Allograft Anterior Cruciate Ligament Reconstruction Fails at a Greater Rate in Patients Younger Than 34 Years

Purpose

To characterize the secondary anterior cruciate ligament (ACL) injury rates after primary allograft anterior cruciate ligament reconstruction (ACLR) and to identify the age cut-score at which the risk of allograft failure decreases.

Methods

All patients who underwent primary ACLR within a single orthopaedic department between January 2005 and April 2020 were contacted at a minimum of 2 years post-ACLR to complete a survey regarding complications experienced post-surgery, activity level, and perceptions of knee health. Patients were excluded for incidence of previous ACLR (ipsilateral or contralateral) and/or age younger than 14 years. Relative proportions were calculated, binary regression analysis was performed, and receiver operating characteristic analysis was used to identify the threshold age for maximal sensitivity and specificity to predict high risk of allograft failure, defined as undergoing revision ACLR.

Results

Of the 939 surveys completed, 398 patients underwent primary allograft ACLR (mean age 39.5 years; range 16.0-66.1 years; 54.3% female). The secondary ACL injury rate was 11.6% (5.8% ipsilateral revision ACLR, 5.8% contralateral ACL injury). Male and female patients had similar revision (5.5% male, 6.0% female, P = .82) and contralateral ACL injury rates (6.6% male, 5.1% female, P = .52). Receiver operating characteristic analysis indicated that age ≤34 years was threshold for differentiating high risk of allograft failure (area under the curve 0.65, 95% confidence interval 0.55-0.76; P = .014). Patients aged ≤34 years had a greater secondary injury rate than patients >34 years (20.4% (10.2% revision ACLR, 10.2% contralateral ACL injury) versus 6.9% (3.5% revision ACLR, 3.5% contralateral ACL injury; P < .001). Binary regression analysis demonstrated that decreasing age was associated with increased risk of graft failure (χ2 = 7.9, P = .02.).

Conclusions

Allograft ACLR showed similar failure rates between sexes but displayed suboptimal graft failure outcomes in younger and active patients. By age 34 years, the increased revision risk for younger patients diminished.

Level of Evidence

Level IV, therapeutic case series.

Poorer functional Outcomes in Patients with Multi-Ligamentous Knee Injury with Concomitant Patellar Tendon Ruptures at 5 years Follow-Up

PURPOSE

Multi-ligamentous knee injuries (MLKIs) are high-energy injuries that may infrequently present with concomitant patellar tendon rupture. There is limited information in the literature regarding these rare presentations, with even less information regarding clinical outcomes. Using propensity-score matching, the purpose of this study was to compare the outcomes of MLKIs with and without patellar tendon ruptures and to investigate the overall predictors of these outcomes.

METHODS

Twelve patients who underwent surgical repair for combined MLKI and patellar tendon rupture from 2011 to 2020 with minimum 1-year follow-up data were identified from two separate institutions. Patients were propensity-score matched with a 1:1 ratio with controls based on age, body mass index (BMI), gender, and time from surgery. Patient-reported outcomes included International Knee Documentation Committee (IKDC) Subjective Knee Form, Lysholm and Tegner scores.

RESULTS

Twelve MLKIs with concomitant patellar tendon injuries were identified out of a multicenter cohort of 237 (5%) patients sustaining MLKI and were case matched 1:1 with 12 MLKIs without extensor mechanism injuries. The average follow-up was 5.5 ± 2.6 years. There were no differences in Schenck Classification injury patterns. There were significant differences found across IKDC (Patellar Tendon mean: 53.1 ± 24.3, MLKI mean 79.3 ± 19.6, P < 0.001) and Lysholm scores (Patellar Tendon mean: 63.6 ± 22.3, MLKI mean 86.3 ± 10.7, P < 0.001) between the two, illustrating poorer outcomes for patients with concomitant patellar tendon ruptures.

CONCLUSION

In the setting of MLKI, patients who have a concomitant patellar tendon rupture have worse functional outcomes compared to those without. This information will be important for patient counseling and might be considered to be added to Schenck classification, reflecting its prognostic value.

LEVEL OF EVIDENCE

Level IV.

Returning Athletes to Sports Following Anterior Cruciate Ligament Tears

PURPOSE OF REVIEW

The purpose of this review is to discuss treatment options, rehabilitation protocols, return-to-play criteria, and expected outcomes after non-operative and operative treatment of anterior cruciate ligament (ACL) tears among an athletic population.

RECENT FINDINGS

Non-operative treatment may be a viable option for some athletes with an ACL tears but can be difficult to predict "copers," and those that resume to sports return at lower performance level and/or less intense activities. Most studies assessing function after ACL reconstruction demonstrate favorable outcomes using patient-reported outcome studies. However, return-to-play and graft re-rupture rates vary substantially based on patient characteristics and level and type of athletic activity. Grafts used to reconstruct ACL produce similar objective outcomes and favorable patient-reported outcomes but have variable re-rupture rates depending on study and differ largely on morbidity associated with graft harvest. Various treatment methods including non-operative and operative techniques have been demonstrated to be efficacious in returning athletes to athletic activity depending on patient age and level of activity. Adherence to fundamental rehabilitation principles and accepted return-to-play guidelines can optimize outcomes and limit re-injury to the injured or contralateral limb.

Pre-operative knee extensor and flexor torque after secondary ACL rupture: a comparative retrospective analysis

Background

Secondary anterior cruciate ligament (ACL) ruptures are a relevant clinical concern after surgical treatment of a primary ACL rupture. However, there is a lack of scientific evidence related to the role of muscle strength prior to revision surgery in a second ACL rupture. The aim of this study was to assess differences in knee extensor and flexor strength in patients before primary and secondary ACL reconstruction compared to healthy controls.

Methods

In total, n = 69 age, weight and sex matched individuals were included in the study: n = 23 patients with isolated primary ACL rupture, n = 23 with secondary ACL rupture, and n = 23 matched healthy controls. Maximal isokinetic knee extension and flexion torque normalized to body mass was assessed for both legs.

Results

For patients with secondary ACL ruptures, torques were reduced in the non-injured (extension: 1.94 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.25 Nm/kg vs. 1.59 Nm/kg, p < 0.05) and the injured leg (extension: 1.70 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.14 Nm/kg vs. 1.59 Nm/kg, p < 0.05) compared to healthy controls. For patients with a primary ACL rupture torques were reduced in the non-injured (extension: 1.92 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.24 Nm/kg vs. 1.59 Nm/kg, p < 0.05) and the injured leg (extension: 1.38 Nm/kg vs. 2.46 Nm/kg, p < 0.05, flexion: 1.01 Nm/kg vs. 1.59 Nm/kg, p < 0.05) compared to healthy controls. There were no differences between patients with primary and secondary ruptures, except of the knee extension on the injured leg showing higher values after a secondary ACL rupture (1.38 Nm/kg vs. 1.70 Nm/kg, p < 0.05).

Conclusions

The findings indicate that maximal knee torques were significantly reduced in patients with primary and secondary ACL ruptures before surgical reconstruction for the non-injured and injured leg as compared to healthy controls. Further investigations are needed to assess strength abilities before and after a second revision within a prospective design.

Single-stage repair of displaced bucket-handle meniscal tears with anterior cruciate ligament reconstruction leads to good meniscal survivorship : a retrospective cohort study

AIMS

The best surgical strategy for the management of displaced bucket-handle (BH) meniscal tears in an anterior cruciate ligament (ACL)-deficient knee is unclear. Combining meniscal repair with ACL reconstruction (ACLR) is thought to improve meniscal healing rates; however, patients with displaced BH meniscal tears may lack extension. This leads some to advocate staged surgery to avoid postoperative stiffness and loss of range of motion (ROM) following ACLR.

METHODS

We reviewed the data for a consecutive series of 88 patients (mean age 27.1 years (15 to 49); 65 male (74%) and 23 female (26%)) who underwent single-stage repair of a displaced BH meniscal tear (67 medial (76%) and 21 lateral (24%)) with concomitant hamstring autograft ACLR. The patient-reported outcome measures (PROMs) EuroQol visual analogue scale (EQ-VAS), EuroQol five-dimension health questionnaire (EQ-5D), Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee score (IKDC), and Tegner score were recorded at final follow-up. A Kaplan-Meier survival analysis was performed to estimate meniscal repair survivorship. Analyses were performed with different cut-offs for meniscal and ACL injury-to-surgery time (within three weeks, three to ten weeks, and more than ten weeks).

RESULTS

Meniscal repair survivorship at a median final follow-up of 55 months (interquartile range (IQR) 24 to 91) was 82% (95% confidence interval 70 to 89). A total of 13 meniscus repairs failed (12 requiring meniscectomy and one requiring a further meniscal repair). At final follow-up, median PROMs were: EQ-VAS 85 (IQR 75 to 90), EQ-5D Index 0.84 (IQR 0.74 to 1.00), KOOS Pain 89 (IQR 80 to 94), KOOS Symptoms 82 (IQR 71 to 93), KOOS Activities of Daily Living 97 (IQR 91 to 100), KOOS Sport and Recreation 80 (IQR 65 to 90), KOOS Quality of Life 69 (IQR 53 to 86), IKDC 82.8 (IQR 67.8 to 90.8), and Tegner 6 (IQR 4 to 7). Two patients underwent revision ACLR following further injuries. One patient had an arthroscopic washout for infection at 11 days post-BH meniscal repair/ACLR. Four patients (4.5%) required a further procedure for stiffness, reduced ROM, and pain, and all were operated on within three weeks of meniscal injury. There was no difference in the interval between meniscal injury and surgery between repairs that failed and those that survived.

CONCLUSION

These data suggest that concomitant ACLR with repair of displaced BH meniscal tears, even if they have been displaced for some time, appears to afford satisfactory PROMs and good survivorship. Repairs within three weeks of meniscal injury may be associated with higher rates of postoperative reintervention for stiffness. Cite this article: Bone Joint J 2022;104-B(6):680-686.

Preoperative muscle thickness influences muscle activation after arthroscopic knee surgery

PURPOSE

The aim of this study was to compare the correlation between preoperative quadriceps femoris muscle thickness and postoperative neuromuscular activation and quadriceps femoris strength in patients with and without patellofemoral pain after arthroscopic partial meniscectomy.

METHODS

A series of 120 patients were prospectively analysed in a longitudinal cohort study of patients scheduled for arthroscopic partial meniscectomy. The patellofemoral pain group included patients who developed anterior knee pain after surgery while the control group included those who had not done so. Patients with preoperative patellofemoral pain, previous knee surgeries as well as those on whom additional surgical procedures had been performed were excluded. Of the 120 initially included in the study, 90 patients were analysed after the exclusions.

RESULTS

There is a direct correlation between preoperative quadriceps femoris muscle thickness and the neuromuscular activity values and the strength of the muscle at 6 weeks after surgery. These results were seen exclusively in the group of patients who do not develop patellofemoral pain (0.543, p = 0.008). The group of patients who developed anterior knee pain in the postoperative period did not show this correlation (n.s.).

CONCLUSION

In patients without patellofemoral pain after meniscectomy, the greater the preoperative thickness of the quadriceps femoris, the more postoperative neuromuscular activation and strength they had. This correlation did not occur in those patients who develop patellofemoral pain after meniscal surgery.

LEVEL OF EVIDENCE

II.

The Clinical Efficacy and Risk Factors after Revision and Reconstruction of Anterior Cruciate Ligament

The aim of this study was to study the clinical efficacy and prognostic factors after revision and reconstruction of anterior cruciate ligament. All the patients who underwent the first revision of anterior cruciate ligament (ACL) reconstruction in the department of sports medicine from January 2001 to December 2015 were collected. The demographic information, the first revision and reconstruction information of ACL, and the information during the first ACL reconstruction were collected. A total of 335 cases were included. Lysholm score, Tegner activity score, and IKDC subjective score at the last follow-up were significantly higher than those before operation. Compared with graft failure caused by sports injury, the postoperative scores of patients with revision due to life accidents or initial reconstruction techniques were significantly lower (P < 0.05). The postoperative Lysholm score of patients with femoral canal drilling through the tibial canal was lower than that of patients with anterior internal approach. The postoperative IKDC score of patients who underwent medial meniscus suture at the same time was higher than that of patients without meniscus combined injury. ACL revision can improve the stability and function of knee joint. Compared with the revision caused by life accident or technical reasons of primary reconstruction surgery, the patients with graft failure caused by sports injury have better postoperative recovery. Medial meniscus suture and anterior internal approach drilling of the femoral bone canal have a statistically protective effect on the clinical function after ACL revision.

ACL Reconstruction Rehabilitation: Clinical Data, Biologic Healing, and Criterion-Based Milestones to Inform a Return-to-Sport Guideline

CONTEXT

Anterior cruciate ligament (ACL) reconstruction (ACLR) and postoperative rehabilitation continues to be a multidisciplinary focus in both research and clinical environments. Recent research on ACLR warrants a reexamination of clinicians' current rehabilitation practices to optimize the strikingly variable clinical outcomes after ACLR and return to sport. The purpose of the article and updated guidelines is to use contemporary evidence to systematically revisit our practice guidelines and validate our clinical milestones with data from our university-based practice.

EVIDENCE ACQUISITION

Using the PubMed search engine, articles that reported on ACLR rehabilitation and protocols, guidelines, graft type, healing and strain, return to sport, psychological considerations, and secondary injury prevention published from 1979 to 2020 were identified using the search terms ACLR protocols, guidelines, ACLR rehabilitation, ACL graft, ACL open kinetic chain (OKC) exercise and closed kinetic chain (CKC) exercise, ACLR return to sport, ACLR psychological factors, and ACL injury prevention.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

Clinical milestones after ACLR were validated using clinical data collected from 2013 to 2017 at a university-based practice. Variables including knee joint range of motion, effusion, Knee Outcome Survey-Activities of Daily Living Scale, and quadriceps strength index were tracked throughout rehabilitation and analyzed to help inform an updated ACLR rehabilitation guideline.

CONCLUSION

Incorporating the latest research, combined with direct clinical data, provides a current, realistic, and clinically benchmarked strategy for ACLR rehabilitation. Commonly held clinical beliefs regarding rehabilitation after ACL injury must be challenged by the latest research to improve patient outcomes and decrease the risk of reinjury. Key updates to the practice guidelines include the use of frequent and accurate quadriceps strength testing, delayed return-to-sport timeline, immediate use of open kinetic chain exercise, criterion-based progressions for running, sprinting, plyometrics, agility, cutting/pivoting, return to competition, and the inclusion of a secondary prevention program after return to sport.

STRENGTH OF RECOMMENDATION TAXONOMY (SORT)

B.

Footwear and Elevated Heel Influence on Barbell Back Squat: A Review

The back squat is one of the most effective exercises in strengthening the muscles of the lower extremity. Understanding the impact of footwear has on the biomechanics is imperative for maximizing the exercise training potential, preventing injury, and rehabilitating from injury. This review focuses on how different types of footwear affect the full-body kinematics, joint loads, muscle activity, and ground reaction forces in athletes of varying experience performing the weighted back squat. The literature search was conducted using three databases, and fourteen full-text articles were ultimately included in the review. The majority of these studies demonstrated that the choice of footwear directly impacts kinematics and kinetics. Weightlifting shoes were shown to decrease trunk lean and generate more plantarflexion relative to running shoes and barefoot lifting. Elevating the heel through the use of external squat wedges is popular method during rehabilitation and was shown to provide similar effects to weightlifting shoes. Additional research with a broader array of populations, particularly novice and female weightlifters, should be conducted to generalize the research results to nonathlete populations. Further work is also needed to characterize the specific effects of sole stiffness and heel elevation height on squatting mechanics.

Retrospective experiences of individuals two decades after anterior cruciate ligament injury - a process of re-orientation towards acceptance

PURPOSE

Individual perspectives of long-term consequences decades after anterior cruciate ligament (ACL) injury are unexplored. We addressed experiences and the impact on life of former athletes >20 years post-ACL injury.

METHODS

Individual interviews, analysed using Grounded Theory, were conducted with 18 persons injured mainly during soccer 20-29 years ago.

RESULTS

A theoretical model was developed with the core category Re-orientation towards acceptance, overarching three categories illustrating the long-term process post-injury. Initially the persons felt like disaster had struck; their main recall was strong pain followed by reduced physical ability and fear of movement and re-injury. In the aftermaths of injury, no participant reached the pre-injury level of physical activity. Over the years, they struggled with difficult decisions, such as whether to partake or refrain from different physical activities, often ending-up being less physically active and thereby gaining body weight. Fear of pain and re-injury was however perceived mainly as psychological rather than resulting from physical limitations. Despite negative consequences and adjustments over the years, participants still found their present life situation manageable or even satisfying.

CONCLUSION

ACL injury rehabilitation should support coping strategies e.g., also related to fear of re-injury and desirable physical activity levels, also with increasing age.IMPLICATIONS FOR REHABILITATIONMore than 20 years after the ACL injury, the individuals despite re-orientation towards acceptance and a settlement with their life situation, still had fear of both pain and re-injury of the knee, with concerns about physical activity and gaining of body weight.Patients with ACL injury may need better individual guidance and health advice on how to remain physically active, to find suitable exercises and to maintain a healthy body weight.Education related to pain, treatment choices, physical activity, injury mechanisms in participatory discussions with the patient about the ACL injury may be beneficial early in the rehabilitation process to avoid catastrophizing and avoidance behaviour.ACL injury rehabilitation needs to address coping strategies incorporating the psychological aspects of suffering an ACL injury, including fear of movement/secondary injury, in order to support return-to-sport and/or re-orientation over time.

Potential In Vitro Tissue-Engineered Anterior Cruciate Ligament by Copolymerization of Polyvinyl Alcohol and Collagen

BACKGROUND AND PURPOSE

Suitable tissue-engineered scaffolds to replace human anterior cruciate ligament (ACL) are well developed clinically as the development of tissue engineering. As water-soluble polymer compound, polyvinyl alcohol (PVA) has been wildly used as the materials to replace ACL. The aim of this study was to explore the feasibility of constructing tissue-engineered ACL by the copolymerization of PVA and collagen (PVA/COL).

METHODS

PVA and COL were copolymerized at a mass ratio of 3:1. The pore size and porosity of the scaffold were observed by electron microscope. The maximum tensile strength of the scaffold was determined by electronic tension machine. The cytotoxicity of the scaffold was evaluated by MTT assay. The morphology of ACL cells cultured on the surface of the scaffold was observed by inverted microscope. The degradation of the scaffold was recorded in the rabbit model.

RESULTS

The average pore size of the polymer scaffold was 100 to 150 μm and the porosity was about 90%. The maximum tensile strength of the scaffold material was 8.10 ± 0.28 MPa. PVA/COL could promote the proliferation ability of 3T3 cells. ACL cells were successfully cultured on the surface of PVA/COL scaffold, with natural growth rate, differentiation, and proliferation. Twenty-four weeks after the plantation of scaffold, obvious degradations were observed in vivo.

CONCLUSION

The model of in-vitro tissue-engineered ACL was successfully established by PVA/COL scaffolds.

Acupuncture and herbal medicine for postoperative care following anterior cruciate ligament reconstruction: A protocol for systematic review and meta-analysis

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) is the primary treatment for patients with anterior cruciate ligament (ACL) injury. Successful postoperative rehabilitation is imperative for their recovery. This protocol details the methods that will be used to systematically analyze the efficacy of acupuncture and herbal medicine for postoperative care following ACLR.

METHODS AND ANALYSIS

Randomized controlled trials will be searched in the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, MEDLINE/PubMed, Chinese National Knowledge Infrastructure, Japan Medical Abstracts Society, and 7 Korean databases (Oriental Medicine Advanced Searching Integrated System, Korean National Assembly Digital Library, Korean Association of Medical Journal Editors, Korean Studies Information Service System, Korean Traditional Knowledge Portal, National Digital Science Library, and Database Periodical Information Academic). The risk of bias will be assessed using the Cochrane assessment tool of risk of bias. The studies that are selected after checking for eligibility will be quantitatively analyzed as a meta-analysis. The primary outcome will be the scores of pain scales, and the secondary outcomes will be the range of motion of the knee, severity of the swelling, and parameters about the knee joint function.

ETHICS AND DISSEMINATION

Ethical approval is not required for this protocol because it does not include patient data. The findings of this review will be disseminated through peer-reviewed publications or conference presentations.

REGISTRATION NUMBER

DOI 10.17605/OSF.IO/ZY2W8 (https://osf.io/zy2w8).

Changes in hamstring strength after anterior cruciate ligament reconstruction with hamstring autograft and posterior cruciate ligament reconstruction with tibialis allograft

Aim

The aim of this study was to evaluate the changes in hamstring strength both after anterior cruciate ligament reconstruction (ACLR) with hamstring autograft followed by early rehabilitation and posterior cruciate ligament reconstruction (PCLR) with tibialis allograft followed by delayed rehabilitation.

Methods

Isokinetic strengths of the quadriceps and hamstring muscles and endurances were compared between a group of 20 patients undergoing PCLR using a tibialis anterior allograft and a 1:2 matched control group of 40 patients undergoing ACLR using a hamstring autograft at 2 years after the operations. Clinical results were also compared using stability tests and the Lysholm and the International Knee Documentation Committee scores.

Results

At 2 years after the operations, the torque deficit of the hamstring muscle in the involved leg compared to the uninvolved leg at both 60°/s and 120°/s was greater in the PCLR group than in the ACLR group (60°/s, 21.8 ± 14.0% versus 1.9 ± 23.9%, P = 0.0171; 120°/s, 15.3 ± 13.7% versus −0.7 ± 17.4%, p = 0.012, respectively). The peak torque of the hamstring muscle at 120°/s was significantly lower in the involved leg than in the uninvolved leg only in the PCLR group (71.3 ± 31.9 N∙m versus 81.9 ± 27.8 N∙m, P = 0.005). There was no significant difference in the clinical results between the groups except for a side-to-side difference in the tibial translation on Telos stress radiographs.

Conclusion

The strength of the hamstring of the PCLR leg with allograft was significantly weaker than that of the unoperated leg after 2 years, whereas that of the ACLR leg with hamstring autograft maintained a similar level of strength compared to that of the uninvolved leg.

Level of evidence

Level III, case–control study.

PATIENTS FOCUS ON PERFORMANCE OF PHYSICAL ACTIVITY, KNEE STABILITY AND ADVICE FROM CLINICIANS WHEN MAKING DECISIONS CONCERNING THE TREATMENT OF THEIR ANTERIOR CRUCIATE LIGAMENT INJURY

BACKGROUND

When deciding medical treatment, patients' perspectives are important. There is limited knowledge about patients' views when choosing non-operative treatment or anterior cruciate ligament (ACL) reconstruction (ACLR) after ACL injury.

PURPOSE

To describe reasons that influenced patients' decisions for non-operative treatment or ACLR after ACL injury.

STUDY DESIGN

Cross-sectional study.

METHODS

This study recruited a total of 223 patients (50% men), aged 28 ± 8 years who had sustained ACL injury, either unilateral or bilateral. Subjects were, at different time points after injury, asked to fill out a questionnaire about their choice of treatment, where an ACLR treatment decision was made, some responded before and some after the ACLR treatment. A rating of the strength of 10 predetermined reasons in their choice of treatment graded as 0 (no reason) to 3 (very strong reason), was done.

RESULTS

Patients with unilateral ACL injury treated with ACLR (110 patients) rated "inability to perform physical activity at the same level as before the injury due to impaired knee function" (96%), "fear of increased symptoms during activity" (87%) and "giving way episodes" (83%) as strong or very strong reasons in their treatment decision. Patients with bilateral ACL injury treated with ACLR (109 knees) rated similar reasons as patients with unilateral ACLR and also "low confidence in the ability to perform at the preinjury activity level without ACLR" (80%) as strong or very strong reasons. Patients with unilateral ACL injury treated non-operatively (46 patients) rated "advice from clinician" (69%) as a strong or very strong reason. Patients with bilateral ACL injury treated non-operatively (25 knees) rated "absence of giving way episodes" (62%), and "no feeling of instability" (62%) as strong or very strong reasons.

CONCLUSION

Inability to perform physical activity, fear of increased symptoms, and giving way episodes were reasons that patients with ACL injury considered when making decisions about ACLR. When choosing non-operative treatment, patients considered the absence of instability or giving way symptoms, being able to perform physical activity, and advice from clinicians.

LEVEL OF EVIDENCE

4.

Biomechanical Evaluation of Preoperative Rehabilitation in Patients of Anterior Cruciate Ligament Injury

Objectives

To investigate the biomechanical characteristics of patients with anterior cruciate ligament (ACL) injury by gait analysis, surface electromyography (SEMG), and proprioception test, and provide rehabilitation suggestions according to the results.

Methods

In this retrospective cohort study, 90 adults with unilateral ACL injury, ranging in age from 19 to 45 years (66 men and 24 women, average age: 30.03 ± 7.91) were recruited for this study form May 2018 to July 2019. They were divided into three groups according to the time after the injury: group A (3‐week to 1.5‐month), group B (1.5‐month to 1 year), and group C (more than 1 year). The SEMG signals were collected from the bilateral rectus femoris (RF), vastus medialis (VM), and vastus lateralis (VL) and the root mean square (RMS) were used to assess muscular activity. SEMG were used to analyze muscles function, gait analysis was used to evaluate the walking stability, balance and location assessment were used to analyze the proprioception.

Results

Through the comparison between bilateral limbs, all muscles strength shown decreased (RF: 239.94 ± 129.70 vs 364.81 ± 148.98, P = 0.001; VM: 298.88 ± 175.41 vs 515.79 ± 272.49, P = 0.001; VL:389.54 ± 157.97 vs 594.28 ± 220.31, P < 0.001) and the division of proprioception became larger (tandem position: 7.79 ± 1.57 vs 6.33 ± 1.49, P = 0.001; stance with one foot: 8.13 ± 0.84 vs 7.1 ± 0.57, P = 0.003; variance of 30°: 6.96 ± 3.15 vs 4.45 ± 1.67, P = 0.03; variance of 60°: 4.64 ± 3.38 vs 2.75 ± 1.98, P = 0.044) in the injured side when compared to the non‐injured and 26 gait parameters were shown difference in group A. In group B, the muscle strength of VL shown decreased (VL: 381.23 ± 142.07 vs 603.9 ± 192.72, P < 0.001) and the division of location of 30° became larger (7.62 ± 4.98 vs 4.33 ± 3.24, P = 0.028) in the injured side when compared to the non‐injured side and there were eight gait parameters that showed differences. In group C, the muscle strength and proprioception showed no differences and only 16 gait parameters showed differences between the bilateral limbs.

Conclusion

The results proved the deterioration of proprioception in 30° of injured side will not recover and non‐injury side and will become worse after 1 year from the injury; among the VL, VM, and RF, the recovery rate of VL is the slowest and bilateral straight leg raising (SLR) (30°) is the best way to train it; the gait stability will be worse after 1 year from the injury. Therefore, we suggest that the training for proprioception in 30° and VL are important for the rehabilitation, and the ACL reconstruction should be performed within 1 year.

The body's integrated repair kit: Studying mesenchymal stem cells for better ligament repair

In this issue of the Biomedical Journal, we learn that the sport injury-prone knee ligaments might harbour their own repair kit in the form of mesenchymal stem cells, and that TERT transformation helps to keep these cells longer in culture for more extensive studies. In addition, we get a demonstration that diffusion tensor imaging can reliably show the activity of specific neural circuits, that rheumatoid arthritis patients are more prone to insulin resistance, and that platelet-enriched plasma gels significantly improve wound healing after pilonidal sinus surgery. Furthermore, two procreation-related articles inform us that growth hormone treatment improves endometrial receptivity in older women, and that elevated maternal liver enzymes do not impact on the outcome of laser therapy for twin-twin transfusion syndrome. Finally, our attention is brought to the importance of subjective well-being evaluation for orthodontic correction needs, as well as the possibility that exercise could maybe increase sperm telomere length.

Anterior cruciate ligament injury risk factors in football

INTRODUCTION

Anterior cruciate ligament (ACL) lesion represents one of the most dramatic injuries in a football (soccer) player's career. There are many injury risk factors related to intrinsic (non-modifiable) and/or extrinsic (modifiable) factors of ACL injury.

EVIDENCE ACQUISITION

Research of the studies was conducted until September 2018 without publication data limitation or language restriction on the following databases: PubMed/MEDLINE, Scopus, ISI, EXCERPTA.

EVIDENCE SYNTHESIS

To date, evidence from the literature suggests that the risk of ACL injury is multifactorial and involves biomechanical, anatomical, hormonal, and neuromuscular factors. Despite this relative complexity, the mechanisms of injury are well known and rationally classified into two categories: mechanisms of injury based on contact or on non-contact with another player, with the non-contact injury mechanisms clearly prevailing over the mechanisms of contact injury. One of the most frequent biomechanical risk factors, associated with ACL non-contact injury, is represented by the valgus knee in the pivoting and cutting movements and in the landing phase after jumping. Gender-related risk factors show female populations to have a higher predisposition to ACL injury than males However, there are still some theoretical and practical aspects that need further investigation such as; genetic risks together with the role of estrogen and progesterone receptors in female populations, and the in-vivo interaction shoe-playing surface. In particular, the genetic risk factors of ACL lesion seem to be an interesting and promising field of investigation, where considerable progress has still to be made.

CONCLUSIONS

This narrative review provides an insight into the risk factors of ACL injury that could be used by practitioners for preventing injury in football (soccer).

The relationship between frontal plane trunk control during landing and lower extremity muscle strength in young athletes after anterior cruciate ligament reconstruction

BACKGROUND

Lower extremity landing asymmetries are common and associated with strength deficits after anterior cruciate ligament reconstruction. However, less is known regarding trunk control during landing. This study's hypotheses were that frontal plane trunk excursion during single-leg landing would be greater in young athletes after anterior cruciate ligament reconstruction compared to controls and would be associated with strength deficits.

METHODS

Participants included 130 young athletes recently cleared for return-to-sport following anterior cruciate ligament reconstruction and 56 uninjured young athletes. Frontal plane trunk excursion was quantified using three-dimensional motion analysis during a single-leg landing task. Quadriceps and hip abduction strength were measured using an isokinetic dynamometer. Frontal plane trunk excursion was compared between the anterior cruciate ligament reconstruction and control groups and among quadriceps strength subgroups using independent t-tests and one-way analysis of variance. Linear regression examined the association between frontal plane trunk excursion and strength measures in the anterior cruciate ligament reconstruction group.

FINDINGS

The anterior cruciate ligament reconstruction group demonstrated greater frontal plane trunk excursion compared to controls. The low-quadriceps group demonstrated greater frontal plane trunk excursion compared to both the high-quadriceps and control groups. Additionally, the high-quadriceps group demonstrated greater frontal plane trunk excursion compared to controls. In the anterior cruciate ligament reconstruction group, lower quadriceps and hip abduction strength were weakly associated with greater frontal plane trunk excursion.

INTERPRETATION

Young athletes at time of return-to-sport after anterior cruciate ligament reconstruction demonstrated increased frontal plane trunk excursion during single-leg landing. Additionally, increased frontal plane trunk excursion was weakly associated with strength deficits.

Systematic Selection of Key Logistic Regression Variables for Risk Prediction Analyses: A Five-Factor Maximum Model

GENERAL AND CRITICAL REVIEW FORMAT

The evolution of clinical practice and medical technology has yielded an increasing number of clinical measures and tests to assess a patient's progression and return to sport readiness after injury. The plethora of available tests may be burdensome to clinicians in the absence of evidence that demonstrates the utility of a given measurement.

OBJECTIVE

Thus, there is a critical need to identify a discrete number of metrics to capture during clinical assessment to effectively and concisely guide patient care.

DATA SOURCES

The data sources included Pubmed and PMC Pubmed Central articles on the topic. Therefore, we present a systematic approach to injury risk analyses and how this concept may be used in algorithms for risk analyses for primary anterior cruciate ligament (ACL) injury in healthy athletes and patients after ACL reconstruction.

MAIN RESULTS

In this article, we present the five-factor maximum model, which states that in any predictive model, a maximum of 5 variables will contribute in a meaningful manner to any risk factor analysis.

CONCLUSIONS

We demonstrate how this model already exists for prevention of primary ACL injury, how this model may guide development of the second ACL injury risk analysis, and how the five-factor maximum model may be applied across the injury spectrum for development of the injury risk analysis.

Contribution of Neuromuscular Factors to Quadriceps Asymmetry After Anterior Cruciate Ligament Reconstruction

CONTEXT

  To quantify quadriceps weakness after anterior cruciate ligament reconstruction (ACLR), researchers have often analyzed only peak torque. However, analyzing other characteristics of the waveform, such as the rate of torque development (RTD), time to peak torque (TTP), and central activation ratio (CAR), can lend insight into the underlying neuromuscular factors that regulate torque development.

OBJECTIVE

  To determine if interlimb neuromuscular asymmetry was present in patients with ACLR at the time of clearance to return to activity.

DESIGN

  Cross-sectional study.

SETTING

  Laboratory.

PATIENTS OR OTHER PARTICIPANTS

  A total of 10 individuals serving as controls (6 men, 4 women; age = 23.50 ± 3.44 years, height = 1.73 ± 0.09 m, mass = 71.79 ± 9.91 kg) and 67 patients with ACLR (43 men, 24 women; age = 21.34 ± 5.73 years, height = 1.74 ± 0.11 m, mass = 77.85 ± 16.03 kg, time postsurgery = 7.52 ± 1.36 months) participated.

MAIN OUTCOME MEASURE(S)

  Isokinetic (60°/s) and isometric quadriceps strength were measured. Peak torque, TTP, and RTD were calculated across isometric and isokinetic trials, and CAR was calculated from the isometric trials via the superimposed burst. Repeated-measures analyses of variance were used to compare limbs in the ACLR and control groups.

RESULTS

  No between-limbs differences were detected in the control group ( P > .05). In the ACLR group, the involved limb demonstrated a longer TTP for isokinetic strength ( P = .04; Cohen d effect size [ES] = 0.18; 95% confidence interval [CI] = -0.16, 0.52), lower RTD for isometric ( P < .001; Cohen d ES = 0.73; 95% CI = 0.38, 1.08) and isokinetic ( P < .001; Cohen d ES = 0.84; 95% CI = 0.49, 1.19) strength, lower CAR ( P < .001; Cohen d ES = 0.37; 95% CI = 0.03, 0.71), and lower peak torque for isometric ( P < .001; Cohen d ES = 1.28; 95% CI = 0.91, 1.65) and isokinetic ( P < .001; Cohen d ES = 1.15; 95% CI = 0.78, 1.52) strength.

CONCLUSIONS

  Interlimb asymmetries at return to activity after ACLR appeared to be regulated by several underlying neuromuscular factors. We theorize that interlimb asymmetries in isometric and isokinetic quadriceps strength were associated with changes in muscle architecture. Reduced CAR, TTP, and RTD were also present, indicating a loss of motor-unit recruitment or decrease in firing rate.

Treadmill training with partial body-weight support after anterior cruciate ligament reconstruction: a randomized controlled trial

[Purpose] To compare the effects of treadmill training with partial body weight support (TTPBWS) and conventional physical therapy (PT) on subjects with anterior cruciate ligament reconstructions. [Subjects and Methods] A total of 40 subjects were randomly allocated to either a treatment group or a control group. Subjects received either treadmill training with partial body weight support (treatment group) or conventional physical therapy (control group). The circumferences of the lower extremities, Holden classifications, 10-meter walking times and the International Knee Documentation Committee (IKDC) scores were compared at 12 and 24 weeks post-operation. The knee joint stability was tested at 24 weeks post-operation using a KT-1000. [Results] Significant differences were found between the two groups at the 12 weeks post-operation. For most of the measures, there was no significant difference between the groups at 24 weeks post-operation. Interestingly, for most of the measures, there was no significant difference between their values in the treatment group at 12 weeks and their values in the control group at 24 weeks post-operation. [Conclusion] The function of a subject’s lower extremities can be improved and the improvement was clearly accelerated by the intervention of treadmill training with partial body weight support, without compromising the stability of the knee joints in a given follow-up period.

Associations between altered movement patterns during single-leg squat and muscle activity at weight-transfer initiation in individuals with anterior cruciate ligament injury

Background

Little is known about factors contributing to the altered movement patterns observed in many individuals with anterior cruciate ligament (ACL) injury. We addressed whether altered muscular activity is such a factor.

Methods

16 participants with unilateral, non-reconstructed ACL rupture were scored for altered movement patterns according to Test for Substitution Patterns (TSP), which includes the single-leg squat (SLS). Surface electromyography (SEMG), was recorded in the lower extremities at initiation of weight-transfer from double-leg to single-leg stance (eyes closed), simulating the initiation of an SLS. Normalised SEMG amplitudes 200–300 ms after weight-transfer initiation were compared between injured and non-injured sides, and correlated to the TSP scores for the SLS. Peak absolute SEMG amplitudes during 5 TSP test movements were also compared between sides.

Results

At weight-transfer initiation, muscle activity was lower in the tibialis anterior, gastrocnemius and peroneus longus muscles on the injured side. Low muscle activity correlated moderately to worse TSP scores for the SLS for the gluteus medius (r_s=−0.56, p=0.03), and gastrocnemius muscles (r_s=−0.56, p=0.02). Median peak absolute amplitude during TSP movements was lower in the quadriceps, gastrocnemius and peroneus longus muscles on the injured side.

Conclusions

The altered patterns of muscle activity at weight-transfer initiation, correlations between lower activity at movement initiation and altered movement patterns during SLS and the altered peak amplitudes during TSP movements together indicate alterations in sensorimotor control that may contribute to the observed altered movement patterns. Future studies will determine if exercises targeting muscle activity initiation should complement customary ACL injury rehabilitation.

The Utility of Limb Symmetry Indices in Return-to-Sport Assessment in Patients With Bilateral Anterior Cruciate Ligament Reconstruction

BACKGROUND

The incidence of contralateral anterior cruciate ligament (ACL) injury after ACL reconstruction (ACLR) is high. Often, return-to-sport (RTS) tests of strength and functional hopping rely on limb symmetry indices (LSIs) to identify deficits, although the utility of these measures in athletes with bilateral ACL injuries is unknown.

PURPOSE/HYPOTHESIS

The aim of this study was to investigate if LSIs used as RTS criteria in female patients after unilateral ACLR were appropriate for female patients with bilateral ACL involvement. The hypothesis tested was that asymmetries with traditional LSI measures would be present in a population after unilateral ACLR but would not be present in a population with bilateral ACLR due to the lack of a healthy internal control limb.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 45 female subjects were classified into 3 groups: after second (contralateral) ACLR (ACLR-B; n = 15); after primary unilateral ACLR (ACLR-U; n = 15); and uninjured controls (CTRL; n = 15). After being cleared for RTS, each subject completed a single-legged hop for distance (SLHD), triple hop for distance (THD), and triple-crossover hop for distance (CHD) test, in addition to an isometric quadriceps strength test on both limbs. Means and LSI ([involved limb/uninvolved limb] × 100) were calculated for each test. Limb symmetry deficits were defined by LSI <90%.

RESULTS

Analysis of functional hop testing revealed a side × group interaction for SLHD (P = .001), THD (P = .019), and CHD (P = .04). Side-to-side differences were found in the ACLR-U group for all hop tests (P = .001-.003) and in the ACLR-B group for SLHD (P = .002) and THD tests (P = .024). No side-to side differences were seen in the CTRL group (P > .05). A side × group interaction was found for isometric quadriceps strength (P = .006), with lower LSI seen in the ACLR-U group (81% ± 17.6%) compared with the CTRL group (102.2% ± 10.8%) and the ACLR-B group (95.6% ± 24.9%). Although no interaction was seen, side-to-side differences were noted in the THD in the ACLR-U group (P = .013) and ACLR-B group (P = .024) and in the CHD in the ACLR-U group (P = .001). Despite absence of an LSI deficit, bilateral peak quadriceps strength in the ACLR-B group was comparable to the involved limb of the ACLR-U group and less than in the CTRL group (P = .012).

CONCLUSION

Both the ACLR-U and the ACLR-B groups demonstrated side-to-side deficits during functional hop tests; however, these deficits were not identified according to the clinically accepted LSI values of ≥90%, calling into question the efficacy of current RTS criteria. At the time of RTS, only individuals in the ACLR-U group demonstrated an altered LSI in quadriceps strength. Significantly lower quadriceps strength of both limbs in the ACLR-B group was seen compared with the CTRL group, despite no LSI deficits in quadriceps strength. Current use of LSIs during strength and performance tests may not be an appropriate means of identifying residual deficits in female patients after bilateral ACLR at time of RTS. Furthermore, a better indicator of strength performance in this population may need to include a comparison of strength performance values to the normative values of healthy controls.

Practicability for robot-aided measurement of knee stability in-vivo

Background

For the analysis of different treatments concerning anterior cruciate ligament (ACL) rupture, objective methods for the quantification of knee stability are needed. Therefore, a new method for in-vivo stability measurement using a robotic testing system should be developed and evaluated.

Methods

A new experimental setting was developed using a KUKA robot and a custom-made chair for the positioning and fixation of the participants. The tibia was connected to the robot via a Vacoped shoe and magnetic buttons, providing adequate safety. Anterior tibial translation and internal tibial rotation were measured on both legs of 40 healthy human subjects at 30°, 60° and 90° of flexion, applying anterior forces of 80 N and internal torques of 4 Nm, respectively.

Results

While the mean differences between the right and left leg measured for anterior tibial translation were within an acceptable range (<1.5 mm), the absolute values were substantially large (38–40.5 mm). For mean internal tibial rotation, between 17.5 and 20° were measured at the different sides and flexion angles, with a maximal difference of 0.75°. High reproducibility of the measurements could be demonstrated for both, anterior tibial translation (ICC(3,1) = 0.97) and internal tibial rotation (ICC(3,1) = 0.94).

Conclusions

Excellent results were achieved for internal tibial rotation, almost reproducing current in-vitro studies, but too large anterior tibial translation was measured due to soft-tissue compression. Therefore, high potential for the analysis of ACL related treatments concerning rotational stability is seen for the proposed method, but further optimization is necessary to enhance this method for the reliable measurement of anterior tibial translation.