Knee joint kinematics after dynamic intraligamentary stabilization: cadaveric study on a novel anterior cruciate ligament repair technique

Anterior Cruciate Ligament Repair-Here to Stay or History Repeating Itself?

Anterior cruciate ligament (ACL) injuries continue to be a prevalent concern among athletes and individuals with an active lifestyle. Traditionally, the standard of care for ACL tears has involved surgical reconstruction using autograft or allograft. This article aims to provide an overview of the evolving landscape of primary ACL repair, examining the current evidence, surgical techniques, patient selection criteria, outcomes, and potential future directions in this field.

Anterior Cruciate Ligament Repair Augmented With Dynamic Intraligamentary Stabilization Is Equivalent to Hamstring Autograft Reconstruction at Short- and Mid-Term Follow-Up: A Systematic Review

PURPOSE

To compare clinical outcomes, knee stability and complications, failure, and revision rates after anterior cruciate ligament repair (ACLr) with dynamic intraligamentary stabilization (DIS) versus anterior cruciate ligament reconstruction (ACLR) with hamstring autograft for primary ACL ruptures at short and mid-term follow-up.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review of PubMed/MEDLINE and Scopus was performed. Studies that evaluated patients undergoing ACLr with DIS or ACLR with hamstring autograft were considered for inclusion. Studies were excluded if patients were affected by concomitant meniscal, ligamentous, or chondral injuries needing surgical treatment, because of their potential confounding effect on postoperative outcomes. The Risk of Bias-2 tool was used to assess the risk of bias in the included studies. The quality of available evidence was rated according to Grading of Recommendations Assessment, Development, and Evaluation recommendations. The study protocol was registered in the PROSPERO database (ID: CRD42023394558).

RESULTS

Five randomized controlled trials comparing the outcomes of ACLr with DIS versus ACLR with hamstring autograft met the inclusion criteria. No major differences in terms of patient-reported outcomes (International Knee Documentation Committee subjective form, Lysholm score, Tegner activity scale, Knee injury and Osteoarthritis Outcome Score, visual analog scale satisfaction) or rates of complications, revisions, and failures were found in included studies at all time points. Repair showed greater International Knee Documentation Committee subjective form scores at 5 years in one study, whereas ACLR displayed significantly increased knee stability at 6 months and 5 years in 2 different studies, although the clinical relevance of these differences is doubtful.

CONCLUSIONS

The results of this study suggest that ACLr with DIS is not inferior to ACLR with hamstring autograft in terms of rates of clinical outcomes, knee stability, risk of failure, complications, and revision surgery. Therefore, ACLr with DIS may be a viable alternative to ACLR with hamstring autograft in selected patients.

LEVEL OF EVIDENCE

Level I, systematic review of Level I studies.

The "Bankart knee": high-grade impression fractures of the posterolateral tibial plateau lead to increased translational and anterolateral rotational instability of the ACL-deficient knee

PURPOSE

The aim of this biomechanical cadaver study was to evaluate the effects of high-grade posterolateral tibia plateau fractures on the kinematics of anterior cruciate ligament (ACL)-deficient joints; it was hypothesized that, owing to the loss of the integrity of the osseous support of the posterior horn of the lateral meniscus (PHLM), these fractures would influence the biomechanical function of the lateral meniscus (LM) and consequently lead to an increase in anterior translational and anterolateral rotational (ALR) instability.

METHODS

Eight fresh-frozen cadaveric knees were tested using a six-degree-of-freedom robotic setup (KR 125, KUKA Robotics, Germany) with an attached optical tracking system (Optotrack Certus Motion Capture, Northern Digital, Canada). After the passive path from 0 to 90° was established, a simulated Lachman test and pivot-shift test as well as external rotation (ER) and internal rotation (IR) were applied at 0°, 30°, 60° and 90° of flexion under constant 200 N axial loading. All of the parameters were initially tested in the intact and ACL-deficient states, followed by two different types of posterolateral impression fractures. The dislocation height was 10 mm, and the width was 15 mm in both groups. The intraarticular depth of the fracture corresponded to half of the width of the posterior horn of the lateral meniscus in the first group (Bankart 1) and 100% of the meniscus width in the second group (Bankart 2).

RESULTS

There was a significant decrease in knee stability after both types of posterolateral tibial plateau fractures in the ACL-deficient specimens, with increased anterior translation in the simulated Lachman test at 0° and 30° of knee flexion (p = 0.012). The same effect was seen with regard to the simulated pivot-shift test and IR of the tibia (p = 0.0002). In the ER and posterior drawer tests, ACL deficiency and concomitant fractures did not influence knee kinematics (n.s.).

CONCLUSION

This study demonstrates that high-grade impression fractures of the posterolateral aspect of the tibial plateau increase the instability of ACL-deficient knees and result in an increase in translational and anterolateral rotational instability.

Therapy-based expert system on function and postural stability after anterior cruciate ligament reconstruction: a pilot study

PURPOSE

Wii Fit exergames have been less commonly used for the rehabilitation of athletes after Anterior Cruciate Ligament Reconstruction (ACLR). This study aims to investigate the effects of an expert system using Wii Fit exergames compared to conventional rehabilitation following ACLR. A forward-chaining rule-based expert system was developed which proposed a rehabilitation program that included the number and type of exercise in terms of difficulty and ease and the duration of each exercise in a progressive manner according to the patient's physical condition.

MATERIALS AND METHODS

Twenty eligible athletes aged 20-30 who underwent ACLR were enrolled in this study and randomly assigned to two groups; and received 12 sessions of either Wii Fit exergames as Wii group (n = 10) or conventional rehabilitation as CL group (n = 10).

RESULTS

The main outcomes consisted of pain (Visual Analogue Scale (VAS)), knee effusion, knee flexion range (KFR), thigh girth (TG), single-leg hop for distance (SLHD), and for time (SLHT), static and dynamic balance tests. Both groups had considerable improvement in all outcomes, also there were significantly differences between Wii and CL groups as follows; VAS (P < 0.001), knee effusion (P < 0.001), TG (P = 0.001), KFR (P = 0.012), static balance in stable position (P < 0.001) and in unstable position (P = 0.001), dynamic balance in the anterior (P < 0.001), posteromedial (P < 0.001), posterolateral (P = 0.004) directions, symmetry index of SLHD (P < 0.001) and symmetry index of SLHT (P = 0.013).

CONCLUSIONS

The findings showed that using Wii Fit exergames in post-ACLR patients reduced pain and effusion while also improving function and balance significantly. Iranian Registry of Clinical Trials registration number is IRCT20191013045090N1, and the registration date is 03-03-2020.

Graft failure and revision rate after ACL repair with dynamic intraligamentary stabilization. One-year results of a prospective case series of 155 patients

PURPOSE

The aim of this study was to assess graft failure, revision rate, and functional outcomes after treatment of acute ACL rupture with dynamic intraligamentary stabilization (DIS) Ligamys device one year post surgery. Additionally, differences in functional outcome between patients with and without anteroposterior laxity were assessed. It was hypothesized that the failure rate of DIS was non-inferior to that of previously reported ACL reconstruction (10%).

METHODS

In this prospectively designed multicenter study, including patients with an acute ACL rupture, DIS was performed within 21 days after rupture. Primary outcome was failure of the graft at 1 year post surgery, defined as 1) re-rupture of the graft, 2) revision of DIS, or 3) a > 3 mm side-to-side difference in anterior tibial translation compared to the non-operated knee (∆ATT), measured by the KT1000 device. Additional analysis was performed using a 5 mm threshold. The subjective International Knee Documentation Committee Score (IKDC) and Numerical Rating Scales (NRS) for pain and confidence were used to evaluate functional outcome.

RESULTS

A total of 155 patients were included with a mean age at surgery of 27.8 years (SD 9.4). The mean interval from rupture to DIS was 16.4 days (SD 5.2). At a median follow-up of 13 months (IQR 12-18) the failure rate of the graft was 30.2% (95%CI:22.0-39.4); 11 patients (7%) required secondary reconstructive surgery and of the 105 patients who attended ATT measurement, 24 patients (23%) had an ∆ATT > 3 mm. Secondary analysis, based on a 5 mm threshold, revealed a failure rate of 22.4% (95%CI: 15.2; 31.1). A total of 39 patients (25%) reported at least one complication, comprising mainly arthrofibrosis, traumatic re-rupture and pain. In these patients, removal of the monoblock was performed in 21 cases (13.5%). At follow-up no significant differences in functional outcomes between patients with ∆ATT > 3 mm and stable ATT were observed.

CONCLUSION

This prospective multicenter study found a high failure rate at one year follow-up of 30% (7% revision surgery and 23% > 3 mm side-to-side difference in anterior tibial translation) in patients treated by primary repair of the ACL with DIS, and did therefore not demonstrate non-inferiority to ACL reconstruction. For patients who did not require secondary reconstructive surgery, this study found good functional outcomes, also in case of persistent anteroposterior knee laxity (∆ATT > 3 mm).

LEVEL OF EVIDENCE

Level IV.

Suture Tape Augmentation Increases the Time-Zero Stiffness and Strength of Anterior Cruciate Ligament Grafts: A Cadaveric Study

Purpose

Methods

Results

Conclusion

Clinical Relevance

Occurrence of inadequate ACL healing after Dynamic Intraligamentary Stabilization and functional outcome-a multicentre case series

Introduction

Dynamic Intraligamentary Stabilization (DIS) is a technique for preservation, anatomical repair and stabilization of a freshly injured anterior cruciate ligament (ACL). The main purpose of this study was to evaluate the short-term re-operation rate when compared to traditional autograft reconstruction.

Methods

Four, from the developer independent, centres enrolled patients that underwent ACL repair by DIS, according to the specific indications given by MRI imaging at a minimum follow-up of 12 months. The re-operation rate was recorded as primary outcome. Secondary outcome measures were the postoperative antero-posterior knee laxity (using a portable Rolimeter®), as well as the Tegner, Lysholm and IKDC Scores.

Results

A total of 105 patients were investigated with a median follow-up of 21 months. Thirteen patients were lost to follow-up. Of the remaining 92 patients 15 (16.3%) had insufficient functional stability and required subsequent ACL reconstruction. These patients were excluded from further analysis, leaving 77 consecutive patients for a 12 months follow-up. The median age at time of surgery was 30 years for that group. At time of follow-up a median antero-posterior translation difference of 2 mm was measured. None of these patients reported subjective insufficiency (giving way), but in 14 patients (18.2%), the difference of antero-posterior translation was more than 3 mm. We found a median Tegner Score of 5.5, a median Lysholm Score of 95.0 and a median IKDC Score of 89.4.

Conclusion

The main finding of this multicentre study is a relevant re-operation rate of 16.3%. Another 18.2% showed objective antero-posterior laxity (≥ 3 mm) during testing raising the suspicion of postoperative non-healing. The failure rate of DIS in this study is higher than for reconstruction with an autologous tendon graft. However, our successfully treated patients had a good clinical and functional outcome based on antero-posterior knee laxity and clinical scores, comparable to patients treated by autograft reconstruction.

Image Enhancement Technology Based on Deep Trust Network Model in Clinical Treatment of Traumatology and Orthopedics

Fractures have brought great pain to patients, and treatment requires a lot of time and yield slow results, which seriously affect the production and life of people. Fractures are mostly treated with traditional conservative treatment methods. For orthopedic trauma, image enhancement technology has gradually played an important role in the clinical treatment of orthopedic trauma and has become a kind of suffering. It has become a new treatment method that attracts people's attention. In order to study the application of image enhancement technology based on the deep trust network model in the clinical treatment of trauma and orthopedics, this paper conducted a related survey of fracture patients in the city's first hospital, reviewed relevant literature, and interviewed professionals, and we collected relevant material, constructed case templates, and created clinical research models using comprehensive quantitative and qualitative analytical techniques. Studies have shown that the use of image enhancement techniques in the treatment of fractures has been successful, with healing efficiency approximately 20% faster than conservative treatment. In the clinical treatment of trauma and orthopedics, image enhancement technology can effectively reduce the incidence of complications in the prognosis of patients. Symptom Drop. This shows that the image enhancement technology of the deep trust network model can play an important role in the clinical treatment of trauma and orthopedics.

Suture Tape Augmentation Has No Effect on Anterior Tibial Translation, Gap Formation, or Load to Failure of Anterior Cruciate Ligament Repair: A Biomechanical Pilot Study

Purpose

The purpose of our pilot study was to assess the effect of augmenting anterior cruciate ligament (ACL) repair with suture tape on biomechanical parameters including anterior tibial translation, gap formation, and load to failure.

Methods

Ten fresh-frozen nonpaired cadaveric knees were dissected, and baseline anterior-posterior stability of both ACL-intact and -deficient knees was obtained. The specimens were randomized to undergo ACL repair either with or without suture tape reinforcement, and anterior tibial translation, as well as gap formation, was measured after cyclic loading. Finally, all specimens were subjected to a single pullout force to determine maximum load to failure. We performed t test analysis to compare means between groups, and significance was defined as P < .05.

Results

On t test analysis, no statistically significant difference was found regarding anterior tibial translation between the ACL-intact group and either repair group or between the repair group without suture tape augmentation and the repair group with suture tape augmentation. No significant difference in gap formation was detected between the repair groups with and without suture tape augmentation at 100 cycles (1.25 mm vs 1.02 mm, P = .6), 250 cycles (2.87 mm vs 2.12 mm, P = .3), and 500 cycles (4.5 mm vs 4.55 mm, P = .5). The average load to failure of the repairs without suture tape augmentation was not significantly different from that of the repairs with suture tape augmentation (725.9 N vs 725.7 N, P = .99).

Conclusions

In this pilot study, we did not identify a difference between ACL repairs with and without suture tape augmentation regarding anterior tibial translation, gap formation, or maximum load to failure.

Clinical Relevance

Treatment of ACL tears with primary ACL repair is a highly debated topic, and studies such as this study to further our understanding of the biomechanical properties of augmented ACL repairs are important for surgeons when deciding the best treatments for their patients.

Knotless Primary Anterior Cruciate Ligament Repair with Adjustable Loop Device and Internal Brace Augmentation

With the recent resurgence of primary anterior cruciate ligament repair, it is important to strive for optimal patient outcomes. This knotless primary repair procedure takes advantage of the use of an adjustable loop device, which allows for intraoperative retensioning by the surgeon. This technical advancement combined with augmentation with an internal brace could potentially minimize gap formation at the repair site, thereby increasing repair stability and ultimate outcome.

Anterior knee translation measurements after ACL reconstruction are influenced by the type of laximeter used

PURPOSE

Laximeters were designed to diagnose an anterior cruciate ligament (ACL) deficient knee, but their use has now focused on providing an objective assessment of the anterior translation (AT) of an intact and ACL-reconstructed knee. In this study we report the introduction and direct comparison of an automated and computerized AT measurement device, GNRB, with the device previously established by the institute and as the current literature standard, the KT1000.

METHODS

A prospective data collection was commenced upon introduction of the GNRB. The measurements of AT in each patient were performed by the same investigator with each device using 134 N applied to both knees, giving a side-to-side difference. The investigators were a sport scientist, a biomechanical engineer and a physiotherapist. Increased AT was defined as a difference > 3 mm.

RESULTS

Three investigators performed the measurements in 122 patients, 9.8 (± 1.8) months after ACL reconstruction. Mean AT of the healthy knee was 5.7 mm with KT1000 and 4.4 mm with GNRB (p = 0.002). Mean AT of the ACL reconstructed knee was 7.0 mm with the KT1000 and 5.3 mm with the GNRB (p = 0.037). The KT1000 had a higher variance of results than the GNRB (p < 0.001). There were 25 patients with increased AT measured by KT1000 compared with 12 patients using the GNRB (p < 0.016), with only 5 on both devices.

CONCLUSIONS

GNRB has better consistency of results when compared to the KT1000. Both devices lack comparability for detecting increased AT, with the KT1000 recording a side-to-side difference of more than 3 mm in twice as many patients as the GNRB.

LEVEL OF EVIDENCE

II.

Good to Excellent Functional Short-Term Outcome and Low Revision Rates Following Primary Anterior Cruciate Ligament Repair Using Suture Augmentation

The aim of this study was to evaluate the functional outcome of primary anterior cruciate ligament (ACL) repair using suture augmentation (SA) in 93 consecutive patients (67 female) with a minimum follow-up of 12 months. Patients’ outcomes were determined using International Knee Documentation Committee (IKDC) score, Lysholm score (LS) and Tegner score (TS). Knee-laxity was assessed using the KT-1000 arthrometer. Eighty-eight patients (67 female, mean age 42 years ± standard deviation (SD) 13) were available for follow-up after a mean time of 21 months (range 12–39). Three patients (3%) underwent revision surgery and were excluded from functional analysis. The mean IKDC score was 87.4 ± 11, mean LS was 92.6 ± 11, mean pre-traumatic TS was 6 ± 2 and mean postoperative TS was 6 ± 2, with a mean difference (TS_Diff) of 1 ± 1. The interval from injury to surgery had no significant impact on the postoperative IKDC (p = 0.228), LS (p = 0.377) and TS_Diff (p = 0.572). Patients’ age (>40 years), BMI (>30) and coexisting ligament or meniscal injuries did not seem to influence postoperative functional results. Primary ACL repair using SA provides good to excellent functional outcomes with a low probability of revision surgery at a minimum of 12 months.

Repair With Dynamic Intraligamentary Stabilization Versus Primary Reconstruction of Acute Anterior Cruciate Ligament Tears: 2-Year Results From a Prospective Randomized Study

BACKGROUND

Anterior cruciate ligament (ACL) repair has once again become a focus of research because of the development of new techniques.

PURPOSE/HYPOTHESIS

The purpose was to compare the functional results and recurrent instability rates in patients undergoing ACL repair with dynamic intraligamentary stabilization (DIS) versus primary ACL reconstruction (ACLR) for acute isolated ACL tears. The hypothesis was that functional results and knee joint stability after ACL repair with DIS would be comparable with that after ACLR.

STUDY DESIGN

Randomized clinical trial; Level of evidence, 1.

METHODS

A total of 85 patients with acute ACL tears were randomized to undergo either ACL repair with DIS or primary ACLR. The preinjury activity level and function were recorded. Follow-up examinations were performed at 6 weeks and 6, 12, and 24 months postoperatively. Anterior tibial translation (ATT) was evaluated using Rolimeter testing. The Tegner activity scale, International Knee Documentation Committee (IKDC) subjective form, and Lysholm knee scoring scale scores were obtained. Clinical failure was defined as ΔATT >3 mm in combination with subjective instability. Recurrent instability and other complications were recorded.

RESULTS

There were 83 patients (97.6%) who were successfully followed until 2 years. ATT was significantly increased in the DIS group compared with the ACLR group (ΔATT, 1.9 vs 0.9 mm, respectively; P = .0086). A total of 7 patients (16.3%) in the DIS group had clinical failure and underwent single-stage revision. In the ACLR group, 5 patients (12.5%) had failure of the reconstruction procedure; 4 of these patients required 2-stage revision. The difference in the failure rate was not significant (P = .432). There were 4 patients (3 in the DIS group and 1 in the ACLR group) who showed increased laxity (ΔATT >3 mm) without subjective instability and did not require revision. Recurrent instability was associated with young age (<25 years) and high Tegner scores (>6) in both groups. No significant differences between ACL repair with DIS and ACLR were found for the Tegner, IKDC, and Lysholm scores at any time.

CONCLUSION

Whereas ATT measured by Rolimeter testing was significantly increased after ACL repair with DIS, clinical failure was similar to that after ACLR. In addition, functional results after ACL repair with DIS for acute tears were comparable with those after ACLR. The current study supports the use of ACL repair with DIS as an option to treat acute ACL tears.

REGISTRATION

DRKS00015466 (German Clinical Trials Register).

Isometric placement of the augmentation braid is not attained reliably in contemporary ACL suture repair

BACKGROUND

To assess if during arthroscopic braid-augmented ACL suture repair (ACLSR), the actual positions of the augmentation braids' tunnels corresponded with the positions of their intended and targeted isometric points, and to test the hypothesis that there would be no dispersion in actual positions of the augmentation braids' tunnels compared to their intended and targeted isometric points.

METHODS

In 12 human cadaveric knees, the positions of the augmentation braids' tunnels and their intended and targeted isometric points relative to a femoral and tibial grid were analysed. Furthermore, vector length between these positions was calculated to assess the accuracy and precision of the augmentation braids' tunnel placement.

RESULTS

There was dispersion for all of the augmentation braids' tunnel positions compared to their intended isometric points. The femoral and tibial vector lengths (mean ± SD (range)) were 2.9 ± 1.0 (1.1-4.1) and 7.1 ± 2.0 (3.2-9.8) mm respectively.

CONCLUSION

In augmented ACLSR, with the ruptured ACL in situ, there was dispersion of the positions of the actual small diameter femoral and tibial augmentation braids' tunnels away from their desired isometric points.

CLINICAL RELEVANCE

The extent of dispersion of the position of both the femoral and tibial tunnels away from their intended isometric positions may cause cyclic length changes with knee motion. An ACLSR with static braid augmentation will thus be vulnerable to cyclic stretching-out. The difficulty of obtaining an isometric tunnel combination for the small diameter augmentation braid may influence the clinician's choice between non-, static or dynamic augmented ACLSR techniques.

Study protocol: a single-blind, multi-center, randomized controlled trial comparing dynamic intraligamentary stabilization, internal brace ligament augmentation and reconstruction in individuals with an acute anterior cruciate ligament rupture: LIBRƎ study

Background

The current gold standard for the treatment of an anterior cruciate ligament (ACL) rupture is reconstruction with tendon graft. Recently, two surgical ACL repair techniques have been developed for treating an acute ACL rupture: Dynamic Intraligamentary Stabilization (DIS, Ligamys®) and Internal Brace Ligament Augmentation (IBLA, InternalBrace™). We will conduct a single-blind, multi-center, randomized controlled trial which compares DIS, IBLA and reconstruction for relative clinical efficacy and economic benefit.

Methods

Subjects, aged 18–50 years, with a proximal, primary and repairable ACL rupture will be included. DIS is preferably performed within 4 weeks post-rupture, IBLA within 12 weeks and reconstruction after 4 weeks post-rupture. Patients are included in study 1 if they present within 0–4 weeks post-rupture and surgery is feasible within 4 weeks post-rupture. Patients of study 1 will be randomized to either DIS or IBLA. Patients are included in study 2 if they present after 4 weeks post-rupture and surgery is feasible between 5 and 12 weeks post-rupture. Patients of study 2 will be randomized to either IBLA or reconstruction. A total of 96 patients will be included, with 48 patients per study and 24 patients per study arm. Patients will be followed-up for 2 years. The primary outcome is change from baseline (pre-rupture) in International Knee Documentation Committee score to 6 months post-operatively. The main secondary outcomes are the EQ-5D-5 L, Tegner score, Lysholm score, Lachman test, isokinetic and proprioceptive measurements, magnetic resonance imaging outcome, return to work and sports, and re-rupture/failure rates. The statistical analysis will be based on the intention-to-treat principle. The economic impact of the surgery techniques will be evaluated by the cost-utility analysis. The LIBRƎ study is to be conducted between 2018 and 2022.

Discussion

This LIBRƎ study protocol is the first study to compare DIS, IBLA and ACL reconstruction for relative clinical efficacy and economic benefit. The outcomes of this study will provide data which could aid orthopaedic surgeons to choose between the different treatment options for the surgical treatment of an acute ACL rupture.

Trial registration

This study is registered at ClinicalTrials.gov; NCT03441295. Date registered 13.02.2018.

The Laxity of the Native Knee: A Meta-Analysis of in Vitro Studies

BACKGROUND

Although soft-tissue balancing plays an important role in knee arthroplasty, we are aware of no objective target parameters describing the soft-tissue tension of the native knee. In the present study, we aimed to meta-analyze data from studies investigating native knee laxity to create a guide for creating a naturally balanced knee joint.

METHODS

PubMed and Web of Science were searched for studies with laxity data published from 1996 through 2016. Graphs were digitally segmented in cases in which numerical data were not available in text or table form. Three-level random-effects meta-analyses were conducted.

RESULTS

Seventy-six studies evaluating knee laxity at various flexion angles (0° to 90°) were included. Knee laxity was significantly different between 0° and 90° of flexion (p < 0.001) in all 6 testing directions, with mean differences of 0.94 mm and -0.35 mm for anterior and posterior translation, 1.61° and 4.25° for varus and valgus rotation, and 1.62° and 6.42° for internal and external rotation, respectively.

CONCLUSIONS

Knee laxity was dependent on the flexion angle of the knee joint in all degrees of freedom investigated. Furthermore, asymmetry between anterior-posterior, varus-valgus, and internal-external rotation was substantial and depended on the joint flexion angle.

CLINICAL RELEVANCE

If the goal of knee arthroplasty is to restore the kinematics of the knee as well as possible, pooled laxity data of the intact soft tissue envelope could be useful as a general guide for soft-tissue balancing in total knee arthroplasty.

Acute Anterior Cruciate Ligament Rupture: Repair or Reconstruction? Two-Year Results of a Randomized Controlled Clinical Trial

BACKGROUND

Contemporary anterior cruciate ligament (ACL) suture repair techniques have been subject to renewed interest in recent years. Although several clinical studies have yielded good short-term results, high-quality evidence is lacking in regard to the effectiveness of this treatment compared with ACL reconstruction.

HYPOTHESIS

Dynamic augmented ACL suture repair is at least as effective as anatomic single-bundle ACL reconstruction for the treatment of acute ACL rupture in terms of patient self-reported outcomes at 2 years postoperatively.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

After stratification and randomization, 48 patients underwent either dynamic augmented ACL suture repair or ACL reconstruction with a single-bundle, all-inside, semitendinosus technique. The International Knee Documentation Committee (IKDC) subjective score at 2 years postoperatively was the primary outcome measure. Patient-reported outcomes (IKDC subjective score, Knee injury and Osteoarthritis Outcome Score, Tegner score, visual analog scale for satisfaction), clinical outcomes (IKDC physical examination score, leg symmetry index for the quadriceps, hamstrings strength, and jump test battery), and radiological outcomes as well as adverse events including reruptures were recorded. Analyses were based on an intention-to-treat principle.

RESULTS

The lower limit for the median IKDC subjective score of the repair group (86.2) fell within the prespecified noninferiority margin, confirming noninferiority of dynamic augmented ACL suture repair compared with ACL reconstruction. No statistical difference was found between groups for median IKDC subjective score (repair, 95.4; reconstruction, 94.3). Overall, 2 reruptures (8.7%) occurred in the dynamic ACL suture repair group and 4 reruptures (19.0%) in the ACL reconstruction group; further, 5 repeat surgeries-other than for revision ACL surgery-took place in 4 patients from the dynamic ACL suture repair group (20.8%) and in 3 patients from the ACL reconstruction group (14.3%).

CONCLUSION

Dynamic augmented ACL suture repair is not inferior to ACL reconstruction in terms of subjective patient-reported outcomes as measured with the IKDC subjective score 2 years postoperatively. However, for reasons other than revision ACL surgery due to rerupture, a higher number of related adverse events leading to repeat surgery were seen in the dynamic augmented ACL suture repair group within 2 years postoperatively.

CLINICAL RELEVANCE

Dynamic augmented ACL suture repair might be a viable treatment option for patients with an acute ACL rupture.

REGISTRATION

NCT02310854 ( ClinicalTrials.gov identifier).

Dynamic intraligamentary stabilization for ACL repair: a systematic review

PURPOSE

It was the aim to assess all published original research dealing with dynamic repair of the anterior cruciate ligament (ACL) and to provide a semi-quantitative analysis of clinical outcome reports.

METHODS

Both OVIS and MEDLINE databases were utilized for allocation of articles. All preclinical and clinical studies related to dynamic intraligamentary stabilization (DIS) were identified. Results were tabulated and semi-quantitative analysis performed.

RESULTS

Twenty-three articles related to DIS were identified. The predominant level of evidence ranged between II and IV, with only one level I study. Reported failure rates ranged between 4% and 13.6%. Most clinical studies only reported revision rates without referring to failure of restoring stability. Highest success was achieved with proximal ACL ruptures. Both the level of physical activity and  patient age have been found to influence the risk of failure.

CONCLUSION

There is sufficient evidence to support that DIS repair may be an effective modality for the treatment of acute proximal tears of the ACL. However, comparative studies are lacking. Upcoming studies should compare the technique to ACL reconstruction with failure as an endpoint. Comparison to rigid methods of proximal fixation is also necessary to justify the need for dynamic fixation. Overall, there is evidence to suggest the potential space for ACL repair in the decision tree for individualized treatment planning. The best outcome will be in the hands of the best patient selectors.

LEVEL OF EVIDENCE

IV.

High complication rate following dynamic intraligamentary stabilization for primary repair of the anterior cruciate ligament

PURPOSE

New strategies for dynamic intraligamentary stabilization (DIS) in the primary repair of anterior cruciate ligament (ACL) ruptures are currently under debate. It has been proposed that these might serve as alternative techniques to conventional ACL reconstruction procedures using tendon autografts. The aims of the present investigation were to evaluate the functional results and critically assess the complication rate following primary ACL repair with DIS and to review existing reports of favourable clinical results with the method in relation to knee joint stability and patient satisfaction.

METHODS

Fifty-nine patients received dynamic intraligamentary stabilization a mean of 14 days after ACL rupture. Fifty-seven patients (96.6%, male:female = 37:20; mean age 27.6 years) were available for follow-up examinations including the Tegner activity level, anteroposterior stability in comparison with the uninjured knee, subjective satisfaction, and range of knee motion. Complications after 3 and 12 months were also analyzed. Associated lesions requiring surgical measures were found in 30 patients.

RESULTS

A statistically significant decrease in Tegner activity levels was detected between the preoperative status (median 7) and the 12-month follow-up (median 5). The overall complication rate was 57.9%, including rerupture or non-healing (n = 10, 17.5%), repeat arthroscopy (n = 13, 22.8%) as a result of meniscus tears (n = 2, 15.4%), cyclops syndrome (n = 4, 30.8%) or restricted range of motion (n = 7, 53.8%), arthrofibrosis (n = 3, 5.3%), and implant interference (n = 7, 12.3%). Anteroposterior KT-1000 stability of 3 mm or below was achieved in 29 (50.9%) patients.

CONCLUSIONS

The DIS procedure does not appear to be appropriate for providing predictable results in a young and active cohort of patients following ACL rupture, as it has an unacceptably high complication rate and leads to residual anteroposterior knee joint laxity of 3 mm or more in 28 (49.1%) of cases.

LEVEL OF EVIDENCE

IV (prospective case series).

Implant preloading in extension reduces spring length change in dynamic intraligamentary stabilization: a biomechanical study on passive kinematics of the knee

PURPOSE

Dynamic intraligamentary stabilization (DIS) is a primary repair technique for acute anterior cruciate ligament (ACL) tears. For internal bracing of the sutured ACL, a metal spring with 8 mm maximum length change is preloaded with 60-80 N and fixed to a high-strength polyethylene braid. The bulky tibial hardware results in bone loss and may cause local discomfort with the necessity of hardware removal. The technique has been previously investigated biomechanically; however, the amount of spring shortening during movement of the knee joint is unknown. Spring shortening is a crucial measure, because it defines the necessary dimensions of the spring and, therefore, the overall size of the implant.

METHODS

Seven Thiel-fixated human cadaveric knee joints were subjected to passive range of motion (flexion/extension, internal/external rotation in 90° flexion, and varus/valgus stress in 0° and 20° flexion) and stability tests (Lachman/KT-1000 testing in 0°, 15°, 30°, 60°, and 90° flexion) in the ACL-intact, ACL-transected, and DIS-repaired state. Kinematic data of femur, tibia, and implant spring were recorded with an optical measurement system (Optotrak) and the positions of the bone tunnels were assessed by computed tomography. Length change of bone tunnel distance as a surrogate for spring shortening was then computed from kinematic data. Tunnel positioning in a circular zone with r = 5 mm was simulated to account for surgical precision and its influence on length change was assessed.

RESULTS

Over all range of motion and stability tests, spring shortening was highest (5.0 ± 0.2 mm) during varus stress in 0° knee flexion. During flexion/extension, spring shortening was always highest in full extension (3.8 ± 0.3 mm) for all specimens and all simulations of bone tunnels. Tunnel distance shortening was highest (0.15 mm/°) for posterior femoral and posterior tibial tunnel positioning and lowest (0.03 mm/°) for anterior femoral and anterior tibial tunnel positioning.

CONCLUSION

During passive flexion/extension, the highest spring shortening was consistently measured in full extension with a continuous decrease towards flexion. If preloading of the spring is performed in extension, the spring can be downsized to incorporate a maximum length change of 5 mm resulting in a smaller implant with less bone sacrifice and, therefore, improved conditions in case of revision surgery.

Dynamic augmentation restores anterior tibial translation in ACL suture repair: a biomechanical comparison of non-, static and dynamic augmentation techniques

PURPOSE

There is a lack of objective evidence investigating how previous non-augmented ACL suture repair techniques and contemporary augmentation techniques in ACL suture repair restrain anterior tibial translation (ATT) across the arc of flexion, and after cyclic loading of the knee. The purpose of this work was to test the null hypotheses that there would be no statistically significant difference in ATT after non-, static- and dynamic-augmented ACL suture repair, and they will not restore ATT to normal values across the arc of flexion of the knee after cyclic loading.

METHODS

Eleven human cadaveric knees were mounted in a test rig, and knee kinematics from 0° to 90° of flexion were recorded by use of an optical tracking system. Measurements were recorded without load and with 89-N tibial anterior force. The knees were tested in the following states: ACL-intact, ACL-deficient, non-augmented suture repair, static tape augmentation and dynamic augmentation after 10 and 300 loading cycles.

RESULTS

Only static tape augmentation and dynamic augmentation restored ATT to values similar to the ACL-intact state directly postoperation, and maintained this after cyclic loading. However, contrary to dynamic augmentation, the ATT after static tape augmentation failed to remain statistically less than for the ACL-deficient state after cyclic loading. Moreover, after cyclic loading, ATT was significantly less with dynamic augmentation when compared to static tape augmentation.

CONCLUSION

In contrast to non-augmented ACL suture repair and static tape augmentation, only dynamic augmentation resulted in restoration of ATT values similar to the ACL-intact knee and decreased ATT values when compared to the ACL-deficient knee immediately post-operation and also after cyclic loading, across the arc of flexion, thus allowing the null hypotheses to be rejected. This may assist healing of the ruptured ACL. Therefore, this study would support further clinical evaluation of dynamic augmentation of ACL repair.

A Narrative Review of Four Different New Techniques in Primary Anterior Cruciate Ligament Repair: "Back to the Future" or Another Trend?

Recently, four different operative techniques, referring to the primary anterior cruciate ligament (ACL) repair, were described. These are the dynamic intraligamentary stabilization (DIS) with Ligamys™, the Bridge-enhanced repair (BEAR), the use of internal brace, and the refixation with suture anchors. The purpose of this study was to assess the already-published, clinical, and pre-clinical results of those techniques. A literature review was conducted and implemented by three independent researchers. Inclusion criteria were clinical or cadaveric or animal studies about patients suffering from ACL rupture, who were treated with one of those four different arthroscopic techniques of primary ACL repair. There were 10 clinical trials dealing with the different techniques of primary ACL repair and 12 cadaveric or animal studies. The majority of the published clinical trials investigated the dynamic intraligamentary stabilization (DIS), while only four studies referred to the three other surgical techniques. Most of the clinical trials suggested that primary ACL repair should be done during the first 14–21 days after a proximal ACL rupture and not later. Further clinical evidence is needed for the techniques of bridge-enhanced ACL repair, internal brace, and suture anchors ACL refixation in order to support the animal and cadaveric biomechanical studies. Till now, the existing clinical trials were not enough to establish the use of those techniques in the ACL-ruptured patients. On the contrary, the Dynamic intraligamentary stabilization with Ligamys™ device demonstrated very promising results in different types of clinical studies.

Changes in gait pattern and early functional results after ACL repair are comparable to those of ACL reconstruction

PURPOSE

Dynamic intraligamentary stabilization (DIS) has been introduced as a new technique to repair the torn anterior cruciate ligament (ACL) and to restore knee joint kinematics after an acute ACL tear. Aim of the present study was to compare the early post-operative activity, restoration of gait pattern and functional results after DIS in comparison with primary ACL reconstruction (ACLR) for acute ACL tears. It was hypothesized that functional results, post-operative activity and changes in gait pattern after DIS are comparable to those after ACLR.

METHODS

Sixty patients with acute ACL tears were included in this study and underwent either DIS or ACLR with an anatomic semitendinosus autograft in a randomized manner. Patients were equipped with an accelerometric step counter for the first 6 weeks after surgery in order to monitor their early post-operative activity. 3D gait analysis was performed at 6 weeks and 6 months after surgery. Temporal-spatial, kinematic and kinetic parameters were extracted and averaged for each subject. Functional results were recorded at 6 weeks, 6 months and 12 months after surgery using the Tegner activity scale, International Knee Documentation Committee score and Lysholm score.

RESULTS

Patients who underwent DIS showed an increased early post-operative activity with significant differences at week 2 and 3 (p = 0.0241 and 0.0220). No significant differences between groups were found for knee kinematic and kinetic parameters or the functional scores at any time of the follow-up. Furthermore, the difference in anterior tibial translation was not significantly different between the two groups (n.s.).

CONCLUSION

Early functional results and changes in gait pattern after DIS are comparable to those of primary ACLR. Therefore, ACL repair may be an alternative to ACLR in this cohort of patients.

LEVEL OF EVIDENCE

I.

Recovery of ACL function after dynamic intraligamentary stabilization is resultant to restoration of ACL integrity and scar tissue formation

PURPOSE

Dynamic intraligamentary stabilization (DIS) is recognized as a ligament preserving technique for the treatment of acute anterior cruciate ligament (ACL) injuries. The aim of this study was to assess the integrity and morphology of the recovered ACL after DIS repair.

METHODS

The cohort comprised 47 patients with an acute proximal ACL rupture undergoing DIS repair. All patients underwent diagnostic arthroscopy after a minimum postoperative interval of 6 months for semi-quantitative evaluation of ACL integrity, function and scar tissue formation. Tegner, Lysholm and International Knee Documentation Committee (IKDC) scores as well as objective anteroposterior (ap) translation were assessed at 6 weeks, 3-, 6-  and 12 months postoperatively.

RESULTS

Full restoration of the ACL volume was affirmed in 30 (63.8%) patients and two-third restoration in 13 (27.7%). Hypertrophic scar formation was observed in 23 (48.9%) patients. Forty-four patients (93.6%) demonstrated sufficient ACL tensioning intraoperatively upon anterior stress. At final follow-up, the median Tegner activity level was 5.5 (3-10), Lysholm and IKDC scores were 100 (64-100) and 94 (55-100) points, respectively. The mean ap-translation differed from the normal knee by 2.1 ± 2.2 mm. Deficient ACL recovery was noted in four patients (8.5%), none of which required secondary reconstructive surgery.

CONCLUSION

The results demonstrate that clinical recovery of ACL function after DIS repair is resultant to both restoration of ACL volume and scar tissue formation. Factors influencing the degree of scar tissue formation need further investigation to enable future attempts of guiding a balanced biological healing response.

LEVEL OF EVIDENCE

IV.

Cost-utility analysis of dynamic intraligamentary stabilization versus early reconstruction after rupture of the anterior cruciate ligament

OBJECTIVES

The aim of this study was to evaluate the cost-effectiveness of the dynamic intraligamentary stabilization (DIS) technique in comparison with reconstructive surgery (ACLR) in the treatment of isolated anterior cruciate ligament (ACL) ruptures from the perspective of the community of insured citizens in Germany.

METHODS

Because of the specific decision problem at hand, namely that with DIS the procedure has to take place within 21 days after the initial trauma, a decision tree was developed. The time horizon of the model was set to 3 years. Input data was taken from official tariffs, payer data, the literature and assumptions based on expert opinion when necessary.

RESULTS

The decision tree analysis identified the DIS strategy as the superior one with 2.34 QALY versus 2.26 QALY for the ACLR branch. The higher QALY also came with higher costs of 5,398.05 € for the DIS branch versus 4,632.68 € for the ACLR branch respectively, leading to an ICER of 9,092.66 € per QALY. Results were robust after sensitivity analysis. Uncertainty was examined via probabilistic sensitivity analysis resulting in a slightly higher ICER of 9,567.13 € per QALY gained.

CONCLUSION

The DIS technology delivers an effective treatment for the ACL rupture at a favorable incremental cost-effectiveness ratio.

Knee joint kinematics with dynamic augmentation of primary anterior cruciate ligament repair - a biomechanical study

Background

Dynamic augmentation of anterior cruciate ligament tears seems to reduce anteroposterior knee translation close to the pre-injury level. The aim of the present study is to biomechanically investigate the course of translation during a simulated early post-operative phase. It is hypothesized that anteroposterior translation is maintained at the immediate post-operative level over a simulated rehabilitation period of 50’000 gait cycles.

Methods

Eight fresh-frozen human cadaveric knee joints from donors with a mean age of 35.5 (range 25–40) years were subjected to 50’000 cycles of 0°-70°-0° flexion-extension movements in a custom-made test setup. Anteroposterior translation was assessed with simulated Lachman/KT-1000 testing in 0°, 15°, 30°, 60° and 90° of flexion in knee joints treated with the novel technique initially and after 50’000 cycles testing. Statistical analysis was performed using the Wilcoxon Signed-Rank Test. The level of significance was set at p = 0.05.

Results

Anteroposterior translation changed non-significantly for all flexion angles between cycle 0 and 50’000 (p = 0.39 to p = 0.89), except for 30° flexion, where a significant increase by 1.4 mm was found (p = 0.03).

Conclusion

Increase in anteroposterior translation of knees treated with this dynamic augmentation procedure is low. The procedure maintains translation close to the immediate post-operative level over a simulated rehabilitation period of 50’000 gait cycles and therefore supports anterior cruciate ligament repair during biological healing.