Functional bracing of ACL injuries: current state and future directions

Functional anterior cruciate ligament braces may have a role in select patient groups although there is presently limited evidence supporting or refuting their routine use: A scoping review of clinical practice guidelines and an updated bracing classification

PURPOSE

The purpose of this study was to perform a scoping review of clinical practice guidelines (CPGs) concerning the use of functional anterior cruciate ligament (ACL) braces and to clarify the nomenclature for bracing relevant to ACL injury treatment in order to support prescribing clinicians.

METHODS

A PubMed search for CPGs for the use of braces following ACL injury or reconstruction was performed. CPGs on the treatment of ACL injuries with sufficient attention to postoperative braces were included in this scoping review. The references used for supporting the specific CPG recommendations were reviewed. Specific indications for brace use including brace type, period of use following surgery and activities requiring brace use were collected.

RESULTS

Six CPGs were identified and included this this review. Three randomised trials provided the evidence for recommendations on functional brace use following ACL reconstruction in the six CPGs. Functional ACL braces were the primary focus of the three randomised trials, although extension braces (postoperative knee immobilisers) were also discussed. A novel dynamic ACL brace category has been described, although included CPGs did not provide guidance on this brace type.

CONCLUSIONS

Guidance on the use of functional ACL braces following ACL reconstruction is provided in six CPGs supported by three randomised trials. However, the brace protocols and patient compliance in the randomised trials render these CPGs inadequate for providing guidance on the use of functional ACL braces in the general and high-risk patient populations when returning to sport after ACL reconstruction. Functional ACL braces are commonly utilised during the course of ACL injury treatment although there is presently limited evidence supporting or refuting the routine use of these braces. Future studies are, therefore, necessary in order to provide guidance on the use of functional and dynamic ACL braces in high-risk patient populations.

LEVEL OF EVIDENCE

Level II.

ChatGPT Provides Unsatisfactory Responses to Frequently Asked Questions Regarding Anterior Cruciate Ligament Reconstruction

PURPOSE

To determine whether the free online artificial intelligence platform ChatGPT could accurately, adequately, and appropriately answer questions regarding anterior cruciate ligament (ACL) reconstruction surgery.

METHODS

A list of 10 questions about ACL surgery was created based on a review of frequently asked questions that appeared on websites of various orthopaedic institutions. Each question was separately entered into ChatGPT (version 3.5), and responses were recorded, scored, and graded independently by 3 authors. The reading level of the ChatGPT response was calculated using the WordCalc software package, and readability was assessed using the Flesch-Kincaid grade level, Simple Measure of Gobbledygook index, Coleman-Liau index, Gunning fog index, and automated readability index.

RESULTS

Of the 10 frequently asked questions entered into ChatGPT, 6 were deemed as unsatisfactory and requiring substantial clarification; 1, as adequate and requiring moderate clarification; 1, as adequate and requiring minor clarification; and 2, as satisfactory and requiring minimal clarification. The mean DISCERN score was 41 (inter-rater reliability, 0.721), indicating the responses to the questions were average. According to the readability assessments, a full understanding of the ChatGPT responses required 13.4 years of education, which corresponds to the reading level of a college sophomore.

CONCLUSIONS

Most of the ChatGPT-generated responses were outdated and failed to provide an adequate foundation for patients' understanding regarding their injury and treatment options. The reading level required to understand the responses was too advanced for some patients, leading to potential misunderstanding and misinterpretation of information. ChatGPT lacks the ability to differentiate and prioritize information that is presented to patients.

CLINICAL RELEVANCE

Recognizing the shortcomings in artificial intelligence platforms may equip surgeons to better set expectations and provide support for patients considering and preparing for ACL reconstruction.

Brace-Free Rehabilitation after Isolated Anterior Cruciate Ligament Reconstruction with Hamstring Tendon Autograft Is Not Inferior to Brace-Based Rehabilitation-A Randomised Controlled Trial

PURPOSE

The postoperative use of a rehabilitative knee brace after isolated primary anterior cruciate ligament (ACL) reconstruction (ACLR) using a hamstring tendon (HT) autograft is controversial. A knee brace may provide subjective safety but can cause damage if applied incorrectly. The aim of this study is to evaluate the effect of a knee brace on clinical outcomes following isolated ACLR using HT autograft.

METHODS

In this prospective randomised trial, 114 adults (32.4 ± 11.5 years, 35.1% women) underwent isolated ACLR using HT autograft after primary ACL rupture. Patients were randomly assigned to wear either a knee brace (n = 58) or no brace (n = 56) for 6 weeks postoperatively. An initial examination was performed preoperatively, and at 6 weeks and 4, 6, and 12 months. The primary endpoint was the subjective International Knee Documentation Committee (IKDC) score to measure participants' subjective perceptions. Secondary endpoints included objective knee function assessed by IKDC, instrumented knee laxity measurements, isokinetic strength tests of the knee extensors and flexors, Lysholm Knee Score, Tegner Activity Score, Anterior Cruciate Ligament-Return to Sport after Injury Score, and quality of life determined by Short Form-36 (SF36).

RESULTS

There were no statistically significant or clinically meaningful differences in IKDC scores between the two study groups (3.29, 95% confidence interval (CI) -1.39 to 7.97, p = 0.03 for evidence of non-inferiority of brace-free compared with brace-based rehabilitation). The difference in Lysholm score was 3.20 (95% CI -2.47 to 8.87); the difference in SF36 physical component score 0.09 (95% CI -1.93 to 3.03). In addition, isokinetic testing did not reveal any clinically relevant differences between the groups (n.s.).

CONCLUSIONS

Brace-free rehabilitation is non-inferior to a brace-based protocol regarding physical recovery 1 year after isolated ACLR using HT autograft. Consequently, the use of a knee brace might be avoided after such a procedure.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Biomechanical Effects of Prophylactic Knee Bracing on Anterior Cruciate Ligament Injury Risk: A Systematic Review

OBJECTIVE

Prophylactic knee braces (PKBs) are widely used by athletes in pivoting and landing sports and have the potential to influence knee movement and alignment, thus modulating anterior cruciate ligament (ACL) injury risk. This systematic review analyses current evidence on the biomechanical effects that PKBs have in the prevention of ACL injuries.

DATA SOURCES

The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Searches were conducted on PubMed, Web of Science, Scopus, Ovid MEDLINE, EMBASE, Cochrane, and CINAHL for studies published from inception until May 31, 2021. Included studies assessed the effects of PKBs on biomechanical variables associated with ACL injuries in landing or pivoting tasks, comparing between braced and unbraced conditions.

MAIN RESULTS

A total of 234 articles were identified; from which, 14 controlled, laboratory, biomechanical studies were included in this review. The effects of PKBs on knee biomechanics could be divided into kinematic variables in the coronal, sagittal, and transverse planes; and common kinetic variables, such as ground reaction force (GRF) and ACL load/strain. Also, PKBs were found to have protective effects in coronal and transverse plane kinematics, but results in the sagittal plane were inconclusive. Assessing knee kinetics, PKBs were advantageous in decreasing ACL load/strain but had no significant effect on GRF.

CONCLUSIONS

Prophylactic knee braces may serve to reduce ACL injury risk by modulating knee coronal and transverse plane movements and ACL load/strain during high-risk maneuvres. Precise recommendations are limited by study heterogeneity. More prospective studies are needed to assess ACL injury risk during high-risk sports using specific PKBs.

Prescription of knee braces after anterior cruciate ligament reconstruction: Fact or fiction?

Objectives: This study aims to compare the clinical results of patients rehabilitated with or without a rehabilitative knee brace (RKB) after anterior cruciate ligament (ACL) reconstruction.

Patients and methods: This retrospective, comparative study was conducted at between January 2013 and December 2017. A total of 119 patients (112 males, 7 females; mean age: 32.0±8.6 years; range, 18 to 45 years) with acute ACL ruptures treated with arthroscopic ACL reconstruction and rehabilitated with (n=56) or without RKB (n=63) participated in the study. The minimum follow-up time was 24 months. The ACL quality of life (QoL) questionnaire, Lysholm Knee Scoring Scale, and Tegner Activity Level Scale were used for the evaluation of the QoL, knee function, and activity level, respectively. The time to return to sports was recorded. The side-to-side difference in the anterior translation of the tibia was measured using a KT-1000 arthrometer.

Results: The mean follow-up time was 38.4±9.1 (range, 24 to 56) months. Baseline demographics and clinical characteristics were similar between groups. Regarding QoL, knee function, and activity level, no significant difference was observed between patients who used RKB and those who did not use it at the postoperative 12th month (p=0.95, p=0.56, p=0.98, respectively) and the latest follow-up (p=0.21, p=0.73, p=0.99, respectively). The mean time to return to sports (nearly 11 months for both groups) and side-to-side difference in the anterior tibial translation at the latest follow-up was also similar between groups (p=0.15 and p=0.15, respectively). There was no graft rupture during the follow-up in both groups. The complication rates were 7.9% and 7.1% for no brace and brace groups, respectively, without a statistically significant difference (p=0.87).

Conclusion: According to the results of this study, there was no significant difference between the rehabilitative brace and no brace groups in clinical outcomes after ACL reconstruction.

Pediatric Anterior Cruciate Ligament Reconstruction: A Reason Not to Wait Until Skeletal Maturity

Anterior cruciate ligament (ACL) tears within the skeletally immature population give rise to controversy regarding the timing of treatment decisions due to the concern of iatrogenic damage to the open physis. Physis disruption from the required intraoperative graft tunnel drilling can lead to growth disturbance, thus ligament reconstruction is not without risk. Nonoperative management carries the risk of future damage to the menisci and cartilage as an ACL-deficient knee can be unstable. This particular case of a skeletally immature 10-year old male demonstrates an initial course of nonoperative treatment which ultimately resulted in previously undiagnosed meniscal damage. Failure of the nonoperative treatment was followed by a successful ACL reconstruction and meniscal repair surgery utilizing a partial physeal sparing technique. The patient successfully returned to his preoperative activity level without any graft disruption, postoperative indications of meniscus pathology, or abnormal growth deformities. This case report adds to the current literature reporting successful and safe ACL reconstructions in a skeletally immature patient.

Functional Bracing Following Anterior Cruciate Ligament Reconstruction: A Critical Analysis Review

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Anterior cruciate ligament (ACL) injuries remain common among athletes; these injuries require reconstruction to restore stability and enable successful return to sport.

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The role of postoperative dynamic knee bracing following ACL reconstruction in protecting graft integrity and promoting return to sport remains largely unknown.

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Limited biomechanical studies on functional bracing have reported decreased strain across the ACL with increasing anterior shear loading.

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Investigations evaluating functional brace use in clinical studies have not yet demonstrated consistent improvement in clinical outcomes, reduced graft retear rates, or improved return-to-sport rates in sports other than skiing.

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Additional investigation examining athletes of various ages participating in different sporting activities is necessary to better understand the role of functional bracing following ACL reconstruction.

Can a Knee Brace Prevent ACL Reinjury: A Systematic Review

This systematic review aimed to investigate whether the use of a knee brace when returning to sport (RTS) could prevent a second injury after anterior cruciate ligament reconstruction (ACLR). This study was registered with the PROSPERO database and followed PRISMA guidelines. A systematic search of PubMed, Ovid Medline, Ovid All EBM Reviews, Ovid Embase, EBSCO Sportdiscus and ISI Web of Science databases for meta-analysis, randomized controlled trials and prospective cohort studies published before July 2020 was undertaken. The inclusion criteria were: (1) Comparing with and without a brace at RTS, (2) follow up of at least 18 months after ACLR, (3) reinjury rates included in the outcomes. Two reviewers independently extracted the data. Quality appraisal analyses were performed for each study using the Cochrane Collaboration tools for randomized and nonrandomized trials. A total of 1196 patients in three studies were included. One study showed a lower rate of reinjury when wearing a knee brace at RTS. One study found the knee brace to have a significant protective effect for younger patients (≤17 years). The effectiveness of knee bracing when RTS remains ambiguous. Current data cannot support that using a knee brace when RTS will decrease the rate of reinjury after ACL reconstruction.

Effect of Different Knee Braces in ACL-Deficient Patients

Knee braces are often used during rehabilitation after ACL injury. There are two main concepts, rigid and soft braces, but studies comparing the two show conflicting results. Most studies used movement tasks with low translational or rotational loads and did not provide joint kinematics. Therefore, the purpose of this study was to investigate the influence of two different knee braces (rigid vs. soft) on knee joint kinematics in ACL-deficient patients compared to an unbraced control condition using two tasks (walking and 180° cutting) provoking knee movements in the frontal and transverse planes. 17 subjects with ACL-deficient knees participated in this study. 3D knee joint kinematics were recorded. To provoke frontal plane knee joint motion a laterally tilting plate was applied during a walking task. Both braces reduced the maximum valgus angle compared to the unbraced condition, stabilizing the knee joint against excessive valgus motion. Yet, no differences in peak abduction angle between the two braces were found. However, a significant extension deficit was observed with the rigid brace. Moreover, both braces increased transverse plane RoM and peak internal rotation angle, with the effects being significantly larger with the rigid brace. These effects have been associated with decreased knee stability and unphysiological cartilage loading. Therefore, the soft brace seems to be able to limit peak abduction with a lesser impact on physiological gait compared to the rigid brace. The cutting task was selected to provoke transverse plane knee movement and large external knee rotation was expected. However, none of the braces was able to reduce peak external knee rotation. Again, an increase in transverse plane RoM was observed with both braces. Based on these results, no brace outmatched the other in the second task. This study was the first attempt to clarify the effect of brace design for the stabilization of the knee joint during movements with frontal and transverse plane loading. However, to provide physicians and patients with a comprehensive guideline for brace usage, future studies will have to extent these findings to other daily or sportive movement tasks.

The negative effects of anterior cruciate ligament injury during stroke rehabilitation

Musculoskeletal problems are commonly reported after stroke resulting in abnormal gait biomechanics, pain, and limitation in performing activities of daily living. Anterior circulate ligament is the most frequently injured knee ligament accounting for approximately 50% of all ligament injuries; however, post stroke anterior cruciate ligament injury is rarely reported. We present a case of a 58-year-old female admitted for inpatient stoke rehabilitation after a left middle cerebral artery stroke. After gaining considerable functional recovery, she was planned to be discharged in two weeks’ time when she tripped resulting in a torn anterior cruciate ligament on the hemiperetic side. This resulted in increase in the length of stay and loss of functional gains. We discuss the possible mechanisms and the management plan. Patients with stroke should be monitored for musculoskeletal complications and preventive strategies should be devised to protect from possible ligamentous injuries of the knees.

Sensitivity of medial-lateral load sharing to changes in adduction moments or angles in an asymptomatic knee joint model during gait

BACKGROUND

Osteoarthritis (OA) of the knee joint is a common disease accompanied by pain and impaired mobility. Despite some recent concerns on the lack of correlation between the medial load and the knee adduction moment (KAM), KAM is routinely considered as a surrogate measure of medial load and hence a marker where its reduction is the main focus of preventive and treatment interventions.

RESEARCH QUESTION

Determine the relative sensitivity of the tibiofemoral medial-lateral contact load partitioning to changes in the knee adduction angle (KAA) versus KAM.

METHODS

Using a lower extremity hybrid musculoskeletal (MS) model driven by gait kinematics and kinetics, we compute here in asymptomatic subjects the sensitivity of the knee joint biomechanical response (muscle and ligament forces) in general and medial/lateral load partitioning in particular to the relative changes in the reported KAA versus changes in reported KAM (both by one standard deviation).

RESULTS

As KAA increased (at constant KAM), so did the passive moment resistance of the knee joint which as a result and at all stance periods substantially reduced forces in lateral hamstrings while increasing those in medial hamstrings. At 25% and 75% stance as two highly loaded periods of gait, the drop in KAA (from + SD to -SD while at constant KAM) drastically reduced the medial contact force by 44% and 30% and the medial over lateral contact load and area ratios by 92% and 79% as well as 64% and 51%, respectively. In contrast, the equivalent alterations in KAM (by ± SD at constant KAA) had lower and less consistent effects (<7%) showing much smaller sensitivity to changes in KAM alone. Ligament forces altered at various stance periods with inconsistent trends; peak values of 418 N in the anterior cruciate ligament (90% carried by the posterolateral bundle) and 1056 N in the patellar tendon were computed both at 25% stance and minimum KAA.

SIGNIFICANCE

These findings indicate a poor correlation between KAM and tibiofemoral load distribution suggesting instead that KAA and knee alignment should be in focus as the primary marker of knee joint load partitioning and associated prevention and treatment interventions.

The Effects of a Compression Garment on Lower Body Kinematics and Kinetics During a Drop Vertical Jump in Female Collegiate Athletes

Background

The use of compression garments has spread rapidly among athletes, largely because of marketing and perceived benefits. Upon review, it is unclear whether compression garments have a significant effect on performance and recovery, although they have been found to enhance proprioception. Further, it is reported that compression of the knee joint improves both dynamic and static balance. However, there is currently a paucity of data demonstrating the effects of compression garments on the biomechanical risk factors of knee-related injuries in female athletes.

Purpose

To evaluate the ability of a directional compression garment to alter hip and knee kinematics and kinetics during a drop vertical jump (DVJ) in healthy college-aged female athletes.

Study Design

Controlled laboratory study.

Methods

A sample of 23 healthy female collegiate athletes (mean age, 19.6 ± 1.3 years) participating in jumping sports (volleyball, basketball, and soccer) was included in this analysis. Each athlete performed 2 sets of 3 DVJs with and without a directional compression garment. Three-dimensional hip and knee kinematics and kinetics were collected using a standard Helen-Hayes 29-marker set, which was removed and reapplied after the garment was fitted, as well as 8 visible-red cameras and 2 force platforms. Each participant was tested in a single session.

Results

Hip abduction range of motion was significantly reduced from 12.6° ± 5.5° to 10.2° ± 4.6° (P = .002) while performing DVJs without and with the compression garment, respectively. No statistically significant differences between conditions were found in peak hip abduction, knee valgus range of motion, peak valgus, peak hip abduction moment, and peak knee valgus moment.

Conclusion

The results of this study show that wearing compression garments does have minimal effects on lower body mechanics during landing from a DVJ, partially supporting the idea that compression garments could acutely alter movement patterns associated with the knee injury risk. However, further research should focus on muscle activation patterns and adaptations over time.

Clinical Relevance

The use of specifically designed compression garments could aid in the prevention of knee injuries by inducing changes in jumping mechanics.

Comparison of Clinical Results, Second-Look Arthroscopic Findings, and MRI Findings Between the Transportal and Outside-In Techniques for Double-Bundle Anatomic Anterior Cruciate Ligament Reconstruction: A Prospective, Randomized Controlled Trial With a Minimum 2-Year Follow-up

BACKGROUND

Although image analysis has shown that the outside-in (OI) technique is associated with different femoral tunnel geometry than the transportal (TP) technique in anatomic anterior cruciate ligament (ACL) reconstruction, it is not known whether clinical results differ between the 2 techniques.

PURPOSE

To compare clinical results, second-look arthroscopic findings, and magnetic resonance imaging (MRI) findings between the TP and OI techniques in anatomic double-bundle (DB) ACL reconstruction.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

From November 2010 to March 2013, 128 patients were enrolled in this study and were randomly assigned to either the TP group (64 patients) or the OI group (64 patients), and DB ACL reconstructions were performed. At the minimum 2-year follow-up (34.9 ± 10.9 months), 111 patients (86.7%) were evaluated with multiple clinical scores and stability tests (KT-2000 arthrometer, Lachman test, and pivot-shift test). Ninety-three knees were evaluated for graft continuity, graft tension, and synovialization by use of second-look arthroscopy. Seventy-eight knees were evaluated on MRI for graft continuity, femoral graft tunnel healing, and graft signal/noise quotient (SNQ). The primary outcome was KT-2000 arthrometer results. Results were compared between the TP and OI groups.

RESULTS

No significant differences were found between the 2 groups in terms of KT-2000 arthrometer results, which was the primary outcome, and other clinical results, with the exception of the postoperative functional test of International Knee Documentation Committee (IKDC) objective score. The ratio of grade A and B on the postoperative functional test of IKDC objective score was significantly larger for the OI group (51/58) than the TP group (36/53) ( P = .005). The second-look arthroscopic findings were not significantly different between the 2 groups in either bundle ( P > .05). In addition, MRI findings did not differ significantly between the 2 groups ( P > .05).

CONCLUSION

With the exception of the functional test of IKDC objective score, we found that clinical results, second-look arthroscopic findings, and MRI findings did not differ significantly between the OI and TP techniques for anatomic ACL reconstruction, although femoral tunnel geometries differed significantly between the 2 techniques.

Patient satisfaction with health is substantially improved following ACL reconstruction

PURPOSE

To prospectively monitor health-related quality of life and return to work after arthroscopic anterior cruciate ligament (ACL) reconstruction in patients with isolated ACL tears.

METHODS

Sixty consecutive patients with isolated ACL tears who underwent arthroscopic ACL reconstruction were prospectively monitored using the "Questions on Life Satisfaction Modules" (FLZ^M) and "Short-Form 12 (SF-12)" quality-of-life outcome measures. The Lysholm score and Tegner activity index were used as functional outcome measures. Additionally, return to work (months) together with level of physical workload was analysed. Outcome measures were assessed the day before surgery and at 6, 12 weeks and 6, 12, and 24 months post-operatively. Quality-of-life outcomes were correlated with functional outcome scores.

RESULTS

Satisfaction with health (FLZ^M) significantly improved within the first 2 years (p < 0.05), and the physical component scale (SF12) showed a significantly higher score after 3, 6, 12 and 24 months as compared with preoperative values (p < 0.05). "General life satisfaction (FLZ^M)" was initially decreased at 6 weeks (p < 0.05) but increased during the further follow-up period, reaching a score not significantly different from preoperative values. Mean Lysholm score improved from 66 preoperatively to 89 post-operatively (p < 0.05) and the median Tegner activity index improved from four to six points (p < 0.05) at final follow-up. Mean time to return to work was 7 weeks (range 1-34 weeks), and it strongly depended on physical workload. A positive correlation between quality of life and functional outcome (Lysholm score) was observed.

CONCLUSION

General life satisfaction is impaired during the early post-operative course, but returns to preoperative values after 2 years. Satisfaction with health reaches higher values after 6, 12 and 24 months post-operatively, and the SF-12 physical component scale was seen to improve during the follow-up period. Improved functional outcomes were observed to correlate with quality-of-life measurements. Thus, patients can preoperatively be informed that they will benefit from ACL reconstruction in terms of an improved knee function and satisfaction with health. Heavy physical workload must be considered as a risk factor for prolonged time lost to return to work. These patients have to be identified and informed about realistic expectations.

LEVEL OF EVIDENCE

II.

Soft-stop knee brace for rehabilitation from ligament injuries: Design and pilot trial

Ligaments within the human knee are commonly torn or injured as a result of sports that involve sharp direction changes, pivoting and landing. For this reason, athletes are often side-lined from their respective sports for up to 18 months after injury to rehabilitate. As part of the rehabilitation process, knee braces are often prescribed in an attempt to decrease the recovery period of the injured individual by restraining and minimizing the motion at the knee. However, the true efficacy of knee bracing is yet to be fully evaluated as studies show mixed results to whether braces actually decrease the rehabilitation period for patients. This paper describes the design and pilot trials of a simple but novel knee brace design that aims to actively aid the rehabilitation of the knee from ligament injuries, primarily the anterior cruciate ligament (ACL). The newly developed knee brace uses an angle locking mechanism with dampers to control both the range of motion of the knee joint and the resistance applied to the knee joint at the limits of extension. Using finite element analysis, these dampers were designed help build muscle strength during everyday use of the knee brace and to reduce the 'jarring effect' which causes significant pain and risk to patients using current knee brace designs. Through providing these features, this new knee brace design has the potential to help improve the extent and speed of recovery for ACL impaired patients.

Two-Stage Revision Anterior Cruciate Ligament Reconstruction Using Allograft Bone Dowels

Revision anterior cruciate ligament (ACL) reconstruction is substantially more challenging than primary reconstruction. Management of previously malpositioned or widened tunnels often requires innovative approaches for managing bony defects. Massive osteolysis with poor bone stock and convergence or overlapping of revision tunnels into the previously placed tunnels may necessitate a staged revision procedure. In this surgical technique description, we describe a method for the management of bony deficiencies using allograft bone dowels in staged revision ACL reconstruction.

Functional Brace in ACL Surgery: Force Quantification in an In Vivo Study

Background:

A need exists for a functional anterior cruciate ligament (ACL) brace that dynamically supports the knee joint to match the angle-dependent forces of a native ACL, especially in the early postoperative period.

Purpose/Hypothesis:

The purpose of this study was to quantify the posteriorly directed external forces applied to the anterior proximal tibia by both a static and a dynamic force ACL brace. The proximal strap forces applied by the static force brace were hypothesized to remain relatively constant regardless of knee flexion angle compared with those of the dynamic force brace.

Study Design:

Controlled laboratory study.

Methods:

Seven healthy adult males (mean age, 27.4 ± 3.4 years; mean height, 1.8 ± 0.1 m; mean body mass, 84.1 ± 11.3 kg) were fitted with both a static and a dynamic force ACL brace. Participants completed 3 functional activities: unloaded extension, sit-to-stand, and stair ascent. Kinematic data were collected using traditional motion-capture techniques while posteriorly directed forces applied to the anterior aspect of both the proximal and distal tibia were simultaneously collected using a customized pressure-mapping technique.

Results:

The mean posteriorly directed forces applied to the proximal tibia at 30° of flexion by the dynamic force brace during unloaded extension (80.2 N), sit-to-stand (57.5 N), and stair ascent (56.3 N) activities were significantly larger, regardless of force setting, than those applied by the static force brace (10.1 N, 9.5 N, and 11.9 N, respectively; P < .001).

Conclusion:

The dynamic force ACL brace, compared with the static force brace, applied significantly larger posteriorly directed forces to the anterior proximal tibia in extension, where the ACL is known to experience larger in vivo forces. Further studies are required to determine whether the physiological behavior of the brace will reduce anterior knee laxity and improve long-term patient outcomes.

Clinical Relevance:

ACL braces that dynamically restrain the proximal tibia in a manner similar to physiological ACL function may improve pre- and postoperative treatment.

Functional Bracing After Anterior Cruciate Ligament Reconstruction: A Systematic Review

INTRODUCTION

The purpose of this study was to evaluate the current literature on the use of functional knee braces after anterior cruciate ligament (ACL) reconstruction with respect to clinical and in vivo biomechanical data.

METHODS

A systematic search of both the PubMed and Embase databases was performed to identify all studies that reported clinical and/or in vivo biomechanical results of functional bracing versus nonbracing after ACL reconstruction. Extracted data included study design, surgical reconstruction techniques, postoperative rehabilitation protocols, objective outcomes, and subjective outcomes scores. The in vivo biomechanical data collected included kinematics, strength, function, and proprioception. Subjective clinical outcomes scores were collected when available. Quality appraisal analyses were performed using the Cochrane Collaboration tools for randomized and nonrandomized trials to aid in data interpretation.

RESULTS

Fifteen studies met the selection criteria (including 3 randomized trials [level II], 11 nonrandomized trials [level II], and 1 retrospective comparative study [level III]), with follow-up intervals ranging from 3 to 48 months. Most studies were designed to compare the effects of functional bracing versus nonbracing on subjective and objective results in patients who underwent previous primary ACL reconstruction. Functional bracing significantly improved kinematics of the knee joint and improved gait kinetics, although functional bracing may decrease quadriceps activation without affecting functional tests, range of motion, and proprioception. Four studies reported no differences in subjective outcomes scores with brace use; however, one study reported increased patient confidence with brace use, whereas another study reported decreased pain and quicker return to work when the brace was not used.

CONCLUSIONS

The effectiveness of postoperative functional bracing following ACL reconstruction remains elusive. Some data suggest that functional bracing may have some benefit with regard to in vivo knee kinematics and may offer increased protection of the implanted graft after ACL reconstruction without sacrificing function, range of motion, or proprioception. However, limited evidence exists supporting the use of routine functional bracing to decrease the rate of reinjury after ACL reconstruction.

An Assessment of Rehabilitation Protocols following Anterior Cruciate Ligament Reconstruction: A Systematic Review

The present study provided a systematic review with meta-analysis of randomized controlled trials involving the effectiveness of various rehabilitation methods that have been implemented for the treatment of anterior cruciate ligament reconstruction (ACLR). The review of the literature revealed the following as evidence for effective ACLR rehabilitation: early intervention strategy focused on restoring range of motion, muscle strength, and ligament stability with the utilization of closed kinetic chain exercises. The literature supports the use of dynamic intraligamentary stabilization, which should also be implemented in the rehabilitation protocol within the first three months after surgery. The research suggests that the patient should undergo at least 30-90 minutes of cryotherapy immediately following ACLR surgery. There is also some evidence regarding the effectiveness of neuromuscular rehabilitation training programs, but further investigations are needed. Future research should consider the timing of rehabilitation as well as supplemental rehabilitation exercises to continue to improve the quality of care delivered to patients following ACLR.

Electromyographic analysis of anterior cruciate deficient knees with and without functional bracing during lunge exercise

BACKGROUND

The use of functional knee braces for returning to sports or during demanding activities following anterior cruciate ligament rupture is common; yet despite being commonly prescribed, its mechanism of action remains unknown.

OBJECTIVES

To examine the effect of functional knee braces on mean muscle activity when performing lunge exercises.

STUDY DESIGN

Pre-/post-test (within-subject research design).

METHODS

A total of 10 male participants with unilateral isolated anterior cruciate ligament deficiency participated. Electromyographic activities of six muscles around the knee were recorded during lunge exercises, with and without wearing a custom functional knee brace. The lunge cycle movement was subdivided into three phases: eccentric, isometric, and concentric.

RESULTS

The quadriceps and hamstrings were no different in the braced and unbraced conditions. When braced, the mean amplitude of the medial gastrocnemius was significantly lower throughout the whole movement (p = 0.01) and during the concentric (p = 0.006) and eccentric (p = 0.028) phases, but not within the isometric phase. The lateral gastrocnemius was found to have lower mean amplitude in the isometric phase (p = 0.044).

CONCLUSION

With its origin on the medial femoral condyle, perhaps reduced medial gastrocnemius activity may better guide knee rotation and assist the joint achieving a healthier kinematic pattern.

CLINICAL RELEVANCE

Lower medial gastrocnemius activity may facilitate lower medial compartment contact pressure, for which greater loading is known to increase the risk of osteoarthritis in anterior cruciate ligament-deficient (ACLD) knees. However, further research is needed.

Anterior cruciate ligament reconstruction, rehabilitation, and return to play: 2015 update

Anatomical discoveries and a growing appreciation of the knee as a complex organ are driving innovations in patient care decision-making following anterior cruciate ligament (ACL) injury. Surgeons are increasing their efforts to restore combined mechanical-neurosensory ACL function and placing more consideration on when to reconstruct versus repair native anatomical structures. Surgical options now include primary repair with or without reinforcing the injured ACL with suture-based internal bracing, and growing evidence supports biological augmentation using platelet-rich plasma and mesenchymal stem cells to enhance tissue healing. Physical therapists and athletic trainers are increasing their efforts to facilitate greater athlete cognitive engagement during therapeutic exercise performance to better restore nonimpaired neuromuscular control activation amplitude and timing. Knee brace design and use needs to evolve to better match these innovations and their influence on the rehabilitation plan timetable. There is a growing appreciation for the multifaceted characteristics of the rehabilitation process and how they influence neuromuscular, educational, and psychobehavioral treatment goal achievement. Multiple sources may influence the athlete during the return to sports process and clinical outcome measures need to be refined to better evaluate these influences. This update summarizes contemporary ACL surgical, medical, and rehabilitation interventions and future trends.

Healing of the Acutely Injured Anterior Cruciate Ligament: Functional Treatment with the ACL-Jack, a Dynamic Posterior Drawer Brace

Background. The injured anterior cruciate ligament (ACL) has a limited healing capacity leading to persisting instability. Hypothesis/Purpose. To study if the application of a brace, producing a dynamic posterior drawer force, after acute ACL injury reduces initial instability. Study Design. Cohort study. Methods. Patients treated with the ACL-Jack brace were compared to controls treated with primary ACL reconstruction und controls treated nonsurgically with functional rehabilitation. Measurements included anterior laxity (Rolimeter), clinical scores (Lysholm, Tegner, and IKDC), and MRI evaluation. Patients were followed up to 24 months. Results. Patients treated with the ACL-Jack brace showed a significant improvement of anterior knee laxity comparable to patients treated with ACL reconstruction, whereas laxity persisted after nonsurgical functional rehabilitation. The failure risk (secondary reconstruction necessary) of the ACL-Jack group was however 21% (18 of 86) within 24 months. Clinical scores were similar in all treatment groups. Conclusion. Treatment of acute ACL tears with the ACL-Jack brace leads to improved anterior knee laxity compared to nonsurgical treatment with functional rehabilitation.