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An introduction to modern anterior cruciate ligament repair

Book - Dissertation

Modern anterior cruciate ligament (ACL) repair was still in “it’s child´s shoes” (translation of Dutch proverb) in 2015. In the following years it became a hot topic in the orthopedic community. Excellent short-term outcomes on open ACL repair were reported in the ´70s with open ACL repair, however high risks of failure were reported after mid-term follow-up. ACL repair was abandoned in favor of ACL reconstruction, which became the gold standard for surgical ACL treatment in the ´80s of the last century. Given the limitations and risks associated with the current gold standard treatment of an ACL rupture, there is room for improvement. Modern ACL repair has theoretically several advantages compared to ACL reconstruction. Modern ACL repair techniques are less invasive and there is no graft harvesting morbidity. Preservation of the native ACL ligament and its proprioceptors contributes in the feedback on position and dynamic stability of the knee, which could reduce the rehabilitation period and decrease the risk of post-traumatic osteoarthritis. Due to the high failure risk of open ACL repair in the past, the orthopedic community is reluctant to start with ACL repair. Data on the modern ACL repair techniques will have to show if the theoretical advantages can be proven in daily practice or if history will repeat itself. Novel ACL repair techniques have been introduced this last decade. The aim of this PhD is to contribute to the discussion if these novel repair techniques could be a treatment option for the acute proximal ACL rupture. If a surgeon would like to start with a new technique, the surgeon prepares him or herself by getting familiar with the surgical technique. In this thesis, the suture tape augmentation (STA) surgical technique is described in detail (Chapter 2). Drawings, pictures and a video have been made to explain the surgical technique, step by step. The indication for STA ACL repair and the rehabilitation protocol as well as the advantages, disadvantages, including the limitations are given. Chapter 2 could contribute in the knowledge of STA ACL repair surgical technique. ACL repair data on the STA ACL repair technique was and still is not extensive. Only one case series of 68 patients with one year follow-up, treated by the developer of the STA technique, was published in 2015. In chapter 3 the results of 42 patients who have been treated by the developer of the STA technique are described. This is the first case series with a 2-year follow-up of the STA ACL repair technique. Several patient reported outcome measures (PROMs) showed a meaningful and or significant improvement (KOOS sport and recreation change, VAS-pain and VR-12 physical scores) in comparison to pre-operative. The Marx activity scale demonstrated a significant decrease in comparison to pre-operative. Two of the 42 patients (4.8%) reported an ACL re‑rupture. The conclusion of this study is that repair with the STA technique could be clinically relevant as a treatment option for patients with an acute, proximal ACL rupture which is not retracted and of good tissue quality. Chapter 4 reports on our own data of 35 patients who have been treated with the STA ACL repair technique at the Antwerp University hospital. This is the first prospective case-series with independent data of the STA ACL repair on adults. The clinical results, re-rupture risk factors and magnetic resonance imaging (MRI) outcomes with a 2-year follow-up after STA ACL repair are reported. This case series shows that STA ACL repair leads to a stable knee, favorable patient-reported outcome measures (PROMs) and quick rehabilitation after surgery, with a median return to work (RTW) period of 5.5 weeks and a return to sports (RTS) period of 6 months. The re-rupture risk is 11.4% and the re-surgery for another reason than re-rupture is 8.6%. A pre-operative Tegner score (activity score) of ≥ 7 was associated with a higher risk on re-rupture. Another significant association was observed between the grade of ACL healing on MRI six months post-operatively and re-rupture (P = .006). When analyzing the effect of age (< 25 versus ≥ 25) on re-rupture, a trend towards significance was observed (P = .061). This study shows that treatment of the acute, repairable ACL with the STA technique leads to a stable knee and favorable PROMs. However, the re-rupture risk of 11% within the 2-year follow-up is a concern. A different ACL repair technique is the dynamic intraligamentary stabilization (DIS) technique. In contrast with the STA technique, the internal brace of the DIS system is dynamic due to the distal fixation in a spring-screw system. This should lead to a more biomechanically stable environment of the knee. The manufacturer of the DIS system advices to repair the ACL within 3 weeks after the rupture, whereas for the STA technique the advised maximum is 3 months. For ACL reconstruction there is no time limit. This changes the management of the ruptured ACL for the DIS technique in a semi-acute trauma. In chapter 5, our experience with the first DIS ACL repairs at the Antwerp University Hospital is described. Starting a new technique involves ‘start-up problems’. Organizing a new patient pathway to treat the patients within 3 weeks after the trauma, dealing with ‘new’ arthroscopic instruments and suture management, post-operative problems and MRI interpretation after ACL repair are examples of the issues we encountered. In two years, 15 patients have been treated with this novel ACL repair technique. From the beginning we meticulously recorded the pre-operative, intra-operative and post-operative problems and our solutions. Tips and tricks that could assist surgeons who are starting with the DIS technique are shared. MRI can be used to evaluate the (repaired) ACL. It is important for the radiologist and orthopedic surgeon to get familiar with the normal MRI appearance of ACL healing after repair, and its potential complications in order to avoid misinterpretation and subsequent unnecessary or delayed surgical intervention. In chapter 6, we have described the normal appearance of the repaired ACL on MRI as well as the possible complications of these techniques. The healing process of the repaired ACL is different compared to ACL reconstruction, without the “ligamentization” phase. Although patients may demonstrate signs of ACL healing on MRI following repair, absence of healing on MRI within the repair can be seen for more than 12 months postoperatively in some patients with clinically stable knees. MRIs after ACL repair should therefore be interpreted with caution, and correlation with clinical findings is necessary. Multiple reviews on ACL repair have been written on a relatively small amount of case‑series the last few years. All these reviews conclude that there is an urge for more data on ACL repair. Long-term follow-up and especially randomized controlled trials between ACL reconstruction, the gold standard and the new ACL repair techniques as well as between the different ACL repair techniques are needed. In 2017, the application for the LIBRƎ study, a multi-center prospective RCT comparing DIS, STA and reconstruction in individuals with an acute ACL rupture was granted by the FWO (Research Foundation Flanders) for the TBM (Applied Biomedical Research with a Primary Social finality) project. With the author as principal investigator, the study started in 2018. The protocol of the LIBRƎ study has been published (Chapter 7). The validated PROMS, clinical, proprioceptive and isokinetic measurements and MRI to determine the clinical efficacy of two alternative techniques, DIS and IBLA, in comparison to the conventional ACL reconstruction for treating an acute ACL rupture will supply a large data pool in which several different aspects of ACL repair versus reconstruction can be compared. The LIBRƎ study is being conducted and could lead to a better comparison between the DIS and STA ACL repair techniques and the gold standard ACL reconstruction. Four different ACL repair techniques have dominated the ACL repair discussion. In chapter 8, a narrative review and critical appraisal of the four different ACL repair techniques, studies by the developers and the early adaptors and the present status is given. After promising short- to mid‑term results by the developers, the results of the early adaptors show more variety in terms of re-rupture and re-surgery for other reasons, which led to a more varicolored discussion. Risk factors for failure are described. There is a call for more clinical data and RCTs. Future research could include conservative management versus ACL repair and reconstruction, as well as the risk on osteoarthritis. ACL repair combined with an anterolateral extra-articular procedure could reduce the re-rupture risk, which could be interesting especially for the high-risk groups. One of the most important findings of the last decade is that the ACL is able to heal and subsequently stabilize the knee again. Patient selection is emphasized: the ideal patient is a non-high athlete older than 25 years with an acute proximal ACL rupture. Further research will have to show if ACL repair could be a game changer or if history will repeat itself. In conclusion: this thesis “An Introduction to Modern Anterior Cruciate Ligament Repair” contributes to the discussion whether these novel repair techniques could be a treatment option for the acute proximal ACL rupture. The ability of the ACL to heal and subsequently re-stabilize the knee with the DIS and the STA repair techniques is confirmed. A step by step description of the ACL STA surgical technique is presented. Our first results and tips and tricks for the DIS repair technique are shared. The healing of the ACL can be monitored with MRI, but correlation with clinical findings is necessary. Based on the two case-series on acute ACL repair with the STA technique it seems that this technique could be clinically relevant as a treatment option for patients with an acute, proximal ACL rupture. A careful patient selection is advised. To reduce the risk on a re-rupture, the ideal patient would be a non-high athlete (Tegner score of < 7) and older than 25 years with an acute proximal ACL rupture of good tissue quality which is not retracted. The call for more data on ACL repair, especially RCTs, is underwritten in the LIBRƎ study protocol and considerations for the future of ACL repair research are given.
Number of pages: 203
Publication year:2021
Keywords:Doctoral thesis
Accessibility:Open