Two-Stage Revision Anterior Cruciate Ligament Reconstruction: A Systematic Review of Bone Graft Options for Tunnel Augmentation

Clinical Outcomes of Single-Stage Revision Anterior Cruciate Ligament Reconstruction Using a Fast-Setting Bone Graft Substitute

Revision anterior cruciate ligament reconstruction (ACLR) can be achieved in a single-stage or two-stage approach. Single-stage revisions have several advantages, including one less operation, decreased cost, and a quicker recovery for patients. Revision ACLR can be complicated by malpositioned or dilated bone tunnels, which makes a single-stage revision more challenging or sometimes necessitates a two-stage approach. The use of fast-setting bone graft substitutes (BGS) has been described in recent literature as a strategy to potentially help address this problem in the setting of single-stage revision ACLR. The aim of this study was to evaluate patient-reported clinical outcomes of patients who have undergone single-stage revision ACLR using fast-setting BGS to address prior malpositioned or dilated tunnels. A retrospective review was conducted of the first nine consecutive patients who had undergone single-stage revision ACLR using a fast-setting BGS by a single surgeon between May 2017 and February 2020 with a minimum of 2-year follow-up. Patient-reported clinical outcomes, including the International Knee Documentation Committee (IKDC) questionnaire, the Tegner Lysholm Knee Scoring Scale, patient satisfaction questions, and the need for additional surgery were evaluated for this group between 26 and 49 months postoperative. Of the nine patients eligible for inclusion, eight patients (88.9%) were evaluated, and one was lost to follow-up. At an average follow-up of 37.9 months (range: 27.8-55.7), the mean postoperative IKDC score was 75.0 ± 11.3, and the mean postoperative Tegner Lysholm Knee Score was 83.0 ± 17.6. None of the patients required additional revision surgery or experienced construct failure at the time of follow-up. Seven of eight respondents (87.5%) had their preoperative expectations met with the surgery, and 100% of patients stated they would have the surgery again. Single-stage revision ACLR using fast-setting BGS showed overall positive clinical outcomes for this pilot group of patients at a minimum 2-year follow-up. In select revision scenarios, these materials may be a valuable option to allow the filling of defects without compromising fixation or clinical outcomes.

Computer Patient-Specific 3D Modeling and Custom-Made Guides for Revision ACL Surgery

Revision anterior cruciate ligament reconstruction (ACLR) is a challenging surgery occurring in 3 to 24% of primary reconstructions. A meticulous planning to study the precise size and location of both femoral and tibial bone tunnels is mandatory. The aim of the study was to evaluate the intra- and interoperator differences in the decision-making process between experienced surgeons after they were asked to make preoperative planning for ACL revision reconstruction with the use of both the computed tomography (CT) scan and a three-dimensional (3D)-printed model of the knee. Data collected from 23 consecutive patients undergoing revision of ACLR for graft failure at a single institute between September 2018 and February 2020 were prospectively reviewed. The double-blinded collected data were presented to three board-certificate attending surgeons. Surgeons were asked to decide whether to perform one-stage or two-stage revision ACLR based on the evaluation of the CT scan images and the 3D-printed custom-made models at two different rounds, T0 and T1, respectively, 7 days apart one from the other. Interoperator consensus following technical mistake was 52% at T0 and 56% at T1 using the CT scans, meanwhile concordance was 95% at T0 and 94% at T1 using the 3D models. Concordance between surgeons following new knee injury was 66% at T0 and 70% at T1 using CT scans, while concordance was 96% both at T0 and T1 using 3D models. Intraoperative variability using 3D models was extremely low: concordance at T0 and T1 was 98%. McNemar test showed a statistical significance in the use of 3D model for preoperative planning (p < 0.005). 3D-printed model reliability resulted to be higher compared with CT as intraoperator surgery technique selection was not modified throughout time from T0 to T1 (p < 0.005). The use of 3D-printed models had the most impact when evaluating femoral and tibial tunnels, resulting to be a useful instrument during preoperative planning of revision ACLR between attending surgeons with medium-high workflow.

Satisfactory outcomes after one-stage revision anterior cruciate ligament reconstruction using rectangular tunnel technique

PURPOSE

One-stage revision anterior cruciate ligament reconstruction (ACLR) with the anatomic rectangular tunnel (RT) technique using bone-patellar tendon-bone (BTB) grafts results in anatomically precise tunnel placement and secure graft fixation. This study evaluated knee joint laxity and clinical outcomes in terms of femoral tunnel overlap. It was hypothesised that there would be no significant differences in knee joint laxity or clinical outcomes regardless of femoral tunnel overlap.

METHODS

Between 2012 and 2021, a single surgeon conducted 196 one-stage revision ACLRs with the RT technique using BTB grafts. Patients were divided based on the presence of femoral tunnel overlap. Knee joint laxity was evaluated using the Lachman test, pivot shift test, and side-to-side difference measured with a KT-1000 arthrometer. Clinical outcomes were assessed using the Lysholm score, Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) Knee Examination Form 2000. Knee joint laxity and clinical outcomes were compared between groups after a median follow-up of 2.5 years (range 2.0-8.0).

RESULTS

The study included 30 and 73 patients in the overlap and non-overlap groups, respectively. No significant differences were observed in the results of the Lachman test, pivot shift test, or KT-1000 arthrometer as well as in the Lysholm, KOOS, or IKDC scores between the two groups. Based on the IKDC scores, all patients were graded as normal or nearly normal.

CONCLUSION

One-stage revision ACLR with the RT technique using BTB grafts improved knee joint laxity and had favourable clinical outcomes regardless of femoral tunnel overlap. To achieve optimal results in one-stage revision ACLR, it is crucial to create a tunnel within the anatomical attachment area and ensure proper graft fixation and tensioning.

LEVEL OF EVIDENCE

III.

Management of anterior cruciate ligament revision in adults: the 2022 ESSKA consensus: part II-surgical strategy

PURPOSE

The aim of this ESSKA consensus is to give recommendations based on scientific evidence and expert opinion to improve the diagnosis, preoperative planning, indication and surgical strategy in Anterior Cruciate Ligament revision.

METHODS

Part 2, presented herein, followed exactly the same methodology as Part 1: the so-called ESSKA formal consensus derived from the Delphi method. Eighteen questions were ultimately asked. The quality of the answers received the following grades of recommendation: Grade A (high level scientific support), Grade B (scientific presumption), Grade C (low level scientific support) or Grade D (expert opinion). All answers were scored from 1 to 9 by the raters. Once a general consensus had been reached between the steering and rating groups, the question-answer sets were submitted to the peer-review group. A final combined meeting of all the members of the consensus was then held to ratify the document.

RESULTS

The review of the literature revealed a rather low scientific quality of studies examining the surgical strategy in cases of ACL reconstruction failure. Of the 18 questions, only 1 received a Grade A rating; 5, a Grade B rating; and 9, grades of C or D. The three remaining complex questions received further evaluations for each portion of the question and were looked at in more detail for the following grades: B and D; A, C and D; or A, B, C and D. The mean rating of all questions by the rating group was 8.0 + - 1.1. The questions and recommendations are listed in the article.

CONCLUSION

ACL revision surgery, especially the surgical strategy, is a widely debated subject with many different opinions and techniques. The literature reveals a poor level of standardization. Therefore, this international European consensus project is of great importance and clinical relevance for guiding the management of ACL revision in adults.

LEVEL OF EVIDENCE

Level II.

Posteromedial Portal Technique With Bone-Patellar Tendon-Bone Graft for Inside-Out Revision of Anterior Cruciate Ligament Reconstruction

Bone-patellar tendon-bone (BTB) is a graft material used in anterior cruciate ligament (ACL) reconstruction. We describe creating a femoral tunnel using an inside-out posteromedial (PM) portal technique during anatomic double-bundle ACL reconstruction with a hamstring graft. We hypothesized that applying this femoral tunnel creation method to the revision ACL reconstruction using BTB would enable reconstruction in 1 stage. In this technique, an anteromedial, an anterolateral, and a PM portal are created to confirm the original ACL footprint and location and direction of the bone tunnel during primary reconstruction. The surgeon then drills from the PM portal, so that the femoral tunnel opening touches the posterior proximal articular cartilage margin in the ACL footprint. Even if the opening partially overlaps with the primary tunnel, it is possible to create a new tunnel with a different direction. Finally, the BTB graft is guided from the tibial tunnel to the femoral tunnel and fixed with interference screws. Intraoperative PM arthroscopic views can confirm that the femoral tunnel has been created, avoiding overlap, and that the revision ACL has been reconstructed. This procedure may be useful for 1-stage revision ACL reconstruction for reinjury after primary ACL reconstruction by other conventional procedures.

Management of Bone Loss and Tunnel Widening in Revision ACL Reconstruction

➤ Both mechanical and biological factors can contribute to bone loss and tunnel widening following primary anterior cruciate ligament (ACL) reconstruction.➤ Revision ACL surgery success is dependent on graft position, fixation, and biological incorporation.➤ Both 1-stage and 2-stage revision ACL reconstructions can be successful in correctly indicated patients.➤ Potential future solutions may involve the incorporation of biological agents to enhance revision ACL surgery, including the use of bone marrow aspirate concentrate, platelet-rich plasma, and bone morphogenetic protein-2.

Consistent Indications and Good Outcomes Despite High Variability in Techniques for Two-Stage Revision Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To systematically review the current literature regarding the indications, techniques, and outcomes after 2-stage revision anterior cruciate ligament reconstruction (ACLR).

METHODS

A literature search was performed using SCOPUS, PubMed, Medline, and the Cochrane Central Register for Controlled Trials according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta Analyses statement. Inclusion criteria was limited to Level I-IV human studies reporting on indications, surgical techniques, imaging, and/or clinical outcomes of 2-stage revision ACLR.

RESULTS

Thirteen studies with 355 patients treated with 2-stage revision ACLR were identified. The most commonly reported indications were tunnel malposition and tunnel widening, with knee instability being the most common symptomatic indication. Tunnel diameter threshold for 2-stage reconstruction ranged from 10 to 14 mm. The most common grafts used for primary ACLR were bone-patellar tendon-bone (BPTB) autograft, hamstring graft, and LARS (polyethylene terephthalate) synthetic graft. The time elapsed from primary ACLR to the first stage surgery ranged from 1.7 years to 9.7 years, whereas the time elapsed between the first and second stage ranged from 21 weeks to 13.6 months. Six different bone grafting options were reported, with the most common being iliac crest autograft, allograft bone dowels, and allograft bone chips. During definitive reconstruction, hamstring autograft and BPTB autograft were the most commonly used grafts. Studies reporting patient-reported outcome measures showed improvement from preoperative to postoperative levels in Lysholm, Tegner, and objective International Knee and Documentation Committee scores.

CONCLUSIONS

Tunnel malpositioning and widening remain the most common indications for 2-stage revision ACLR. Bone grafting is commonly reported using iliac crest autograft and allograft bone chips and dowels, whereas hamstring autograft and BPTB autograft were the most used grafts during the second-stage definitive reconstruction. Studies showed improvements from preoperative to postoperative levels in commonly used patient reported outcomes measures.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I, III, and IV studies.

Editorial Commentary: It is Never Wrong to Perform Anterior Cruciate Ligament Revision Reconstruction as a Two-Stage Procedure

Revision anterior cruciate ligament (ACL) reconstruction can be performed in a single surgery, but in some instances, it requires 2 stages to get it right. The most common reasons for staged reconstruction include dilated bone tunnels on the tibial or femoral side (>13 mm), imperfectly placed bone tunnels that cannot be reused but cannot be avoided, and/or the need to combine the revision ACL reconstruction with meniscus and/or cartilage allograft transplantation. In my practice, we use prefabricated bone dowels, sizing up 0.5 to 1 mm relative to the size of the tunnel (after debridement) for both the femoral side and tibial side. The benefits are efficiency and reproducibility, while the challenges include cost and the potential need for multiple dowels if the prefabricated dowels are not long enough. We will occasionally add demineralized bone matrix, particularly on the tibial side, in the event that there is <5 mm of unfilled tunnel using the bone dowel. We wait ∼3 months before proceeding to the second stage using only plain radiographs to assess healing (advanced imaging such as computed tomography scan is not routinely used). We have also begun to push the limits of single-stage revision reconstruction, using dowels in a single setting. No matter what, it is never wrong to perform ACL revision reconstruction as a 2-stage procedure. When performed for the appropriate indications, outcomes tend to be good, regardless of the chosen technique.

Revision anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) graft failure from rupture, attenuation, or malposition may cause recurrent subjective instability and objective laxity, and occurs in 3% to 22% of ACL reconstruction (ACLr) procedures. Revision ACLr is often indicated to restore knee stability, improve knee function, and facilitate return to cutting and pivoting activities. Prior to reconstruction, a thorough clinical and diagnostic evaluation is required to identify factors that may have predisposed an individual to recurrent ACL injury, appreciate concurrent intra-articular pathology, and select the optimal graft for revision reconstruction. Single-stage revision can be successful, although a staged approach may be used when optimal tunnel placement is not possible due to the position and/or widening of previous tunnels. Revision ACLr often involves concomitant procedures such as meniscal/chondral treatment, lateral extra-articular augmentation, and/or osteotomy. Although revision ACLr reliably restores knee stability and function, clinical outcomes and reoperation rates are worse than for primary ACLr.

Bone Marrow Aspirate Concentrate With Two-Staged-Revision ACL Reconstruction

Background:

The incidence of anterior cruciate ligament (ACL) injuries, reconstructions, and re-ruptures has rapidly increased. Patients with failed ACL reconstructions have been reported to suffer from far worse outcomes as compared with those with primary reconstructions, prompting the advancement of surgical and biologic techniques. Effective treatment of re-tears has been shown to be achieved either utilizing a 1-stage or 2-staged approach, with the latter preferred if the patient presents with significant bone loss, previously malpositioned tunnels, or unacceptable tunnel expansion. Recent literature has shown the efficacy of bone marrow aspirate concentrate (BMAC) in improving clinical outcomes and graft integration as well as accelerated ligamentization.

Indication:

Patients are indicated for surgery when presenting with chronic ACL graft failure and objective insufficiency as well as concerns regarding tunnel overlap, enlargement, or interference. Contraindications for revision involve influences of concurrent injuries that may be secondary causes of the ACL injury.

Technique Description:

After bone marrow aspiration is performed, the tibial and femoral tunnel apertures are debrided of fibrous tissue with a combination of a shaver and curettes. A threaded guide wire is passed and the interference screws are removed, revealing the residual ruptured graft. A shaver and radiofrequency ablation device are utilized to clean off remaining graft remnants. Sequential debridement and reaming are performed to remove any residual fibrous tissue or sclerotic bone from the tunnel. The demineralized bone matrix is then combined with the prepared BMAC in a syringe with a cannula extension and subsequently injected into the tunnels. A freer elevate is used to tamp and smooth the graft to match the surrounding contour. A 12-mm cannulated allograft bone dowel is then passed up into the tibial tunnel and gently tamped into place.

Results:

Within 2 years postoperatively, patients are expected to have improved overall knee-specific quality of life, reduced pain, and a successful return to activities. No differences in outcomes have been noted in the literature between 1-staged and 2-staged ACL reconstructions.

Discussion/Conclusion:

Recent advancements in our understanding of the effects of BMAC in the setting of an ACL reconstruction should prompt surgeons to consider such treatments in indicated patients.

Patient Consent Disclosure Statement:

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Tunnel Management in Revision Anterior Cruciate Ligament Reconstruction: Current Concepts

Bone tunnel-related complications are frequently encountered during revision anterior cruciate ligament reconstruction (ACLR). Issues with tunnel positioning, enlargement, containment, and hardware interference may complicate surgery and compromise outcomes. As a result, several strategies have emerged to address these issues and optimize results. However, a systematic, unified approach to tunnel pathology in revision ACLR is lacking. The purpose of this review is to highlight the current state of the literature on bone tunnel complications and, although extensive literature on the subject is lacking, present an updated approach to the evaluation and management of tunnel-related issues in revision ACLR.

Failure of primary ACL repair with dynamic intraligamentary stabilization may result in a high risk of two-stage ACL reconstruction: a case series of ten patients

PURPOSE

Dynamic Intraligamentary Stabilization (DIS) is a technique for the repair of acute anterior cruciate ligament (ACL) injuries. The purpose of this study was to investigate the potential challenges of ACL reconstruction (ACLR) following failure of DIS.

METHODS

A retrospective analysis of patients with failure of primary ACL repair performed with DIS was undertaken. Failure was defined as abnormal knee laxity (positive Lachman and/or pivot shift) and/or severely restricted range of motion. Medical and surgical records were reviewed and preoperative standard anteroposterior and lateral X-rays were assessed.

RESULTS

Between July 2015 and May 2022, 10 patients (3 males, 7 females, median age 28 years, range 18-52 years) with failure of DIS were referred to and surgically treated at a single centre. In four patients, single-stage ACLR was performed following the removal of the tibial monoblock. In six patients, arthrofibrosis and excessive tibial tunnel enlargement following the removal of the monoblock prevented single-stage ACLR. These patients underwent arthroscopic arthrolysis and tibial tunnel bone grafting as a first-stage revision procedure.

CONCLUSION

In the present case series, single-stage ACLR was performed in only four (40%) of ten patients following failure of ACL repair with DIS. Arthrofibrosis and excessive tibial tunnel enlargement following the removal of the monoblock prevented single-stage ACLR in six (60%) patients. It is important for clinicians to inform patients that, in the event of failure of ACL repair with DIS, they may run a high risk of undergoing two-stage ACLR.

LEVEL OF EVIDENCE

Level IV, Case Series.

Controversies in ACL revision surgery: Italian expert group consensus and state of the art

Background

Revision ACL reconstruction is a complex topic with many controversies and not-easy-to-make decisions. The authors’ aim is to provide some feasible advice that can be applied in daily clinical practice with the goal of facilitating the decision-making process and improving the outcomes of patients subjected to revision ACL reconstruction.

Methods

A national survey with seven questions about the most controversial topics in revision ACL reconstruction was emailed to members of two societies: SIOT and SIAGASCOT. The participants’ answers were collected, the most recent literature was analyzed, and a consensus was created by the authors, according to their long-term surgical experience.

Conclusions

The decision-making process in revision ACL reconstruction starts with a standardized imaging protocol (weight-bearing radiographs, CT scan, and MRI). One-stage surgery is indicated in almost all cases (exceptions are severe tunnel enlargement and infection), while the choice of graft depends on the previously used graft and the dimensions of the tunnels, with better clinical outcomes obtained for autografts. Additional procedures such as lateral extra-articular tenodesis in high-grade pivot-shift knees, biplanar HTO in the case of severe coronal malalignment, and meniscal suture improve the clinical outcome and should be considered case by case.

Level of evidence

V (Expert opinion).

Bone Grafting Technique in Revision ACL Reconstruction: Coring Reamer and Dowel Trick

One- or two-staged bone grafting is sometimes required for tunnel malposition and/or tunnel widening in revision anterior cruciate ligament (ACL) reconstruction. The aim of this procedure is to restore the correct position of the ACL graft in the revision setting to provide a stable and functional ACL, thereby reproducing normal knee kinematics. We present a technique that allows for a cost-effective, convenient tunnel grafting of a femoral head allograft bone dowel into both femoral and tibial defects in revision ACL reconstruction.

Arthroscopic Revision of Attenuated Anterior Cruciate Ligament Graft With Enlarged Bone Tunnels Using Injectable Bone Graft Substitute

Revision anterior cruciate ligament (ACL) reconstruction is a technically demanding procedure, and the surgeon should be prepared to address bone tunnel osteolysis, concurrent meniscal, ligamentous, or cartilage lesions, and limb malalignment. ACL revision can typically be done in one procedure, but it may need to be staged if there is poor previous tunnel positioning or excessive tunnel osteolysis. Bone grafting of the tunnels can be accomplished in several ways, including autograft, allograft, or bone substitutes. Currently, no consensus is available regarding the optimal choice of bone graft material for bone tunnel augmentation in revision ACL reconstruction. Bone graft substitute for tunnel augmentation has been showed to have good histologic, radiographic, and intraoperative integration, comparable to that of autologous bone. In this Technical Note, the technical details of arthroscopic treatment of attenuated anterior cruciate ligament graft with enlarged bone tunnels are described. The tunnels are debrided arthroscopically and filled up with PRO-DENSE injectable regenerative graft.

Psychological, physical and social factors influence decision to return to sport after revision ACL reconstruction with BPTB graft

PURPOSE

There is limited evidence in literature regarding the patient-reported factors that influence their return to sport (RTS) in revision anterior cruciate ligament reconstruction (ACLR). The medium-term results of a prospective consecutive cohort of patients undergoing single- and two-stage revision ACLR with bone patellar tendon bone graft (BPTB) and patient-reported factors that influence their decision to return to sport are presented in this study.

METHODS

Seventy-two patients were included in this prospective study. Single- or two-stage revision with BPTB graft was performed based on pre-operative planning. Iliac crest bone graft was used. Pre-operative and follow-up Lysholm and Tegner activity scores and RTS, level of sport and patient-reported factors affecting RTS were recorded. The mean follow-up was 9 years (SD 2.7 years).

RESULTS

Single-stage revision ACLR was performed in 61 patients. In 11 patients (15%), revision ACLR was performed in two stages. There was a significant improvement in Lysholm score from mean 51.1 to 86.7 (p < 0.001). The incidence of re-rupture in this cohort was 0%. The median Tegner score was 6 (range 2-9). Twenty-five patients (34.7%) did not return to any sport at final follow-up. Twenty-nine (40.2%) patients returned to their pre-injury level of sport. Fear of reinjury (79%, p < 0.001) and persistent knee symptoms (35.8%, p = 0.03) were the most common factors limiting RTS in non-returners.

CONCLUSION

Psychological and social factors may have an influence on RTS in addition to physical factors.

LEVEL OF EVIDENCE

Level III.

One-Stage ACL Revision Using a Bone Allograft Plug for a Semianatomic Tibial Tunnel That Is Too Anterior

Revision of an anterior cruciate ligament (ACL) reconstruction can be performed as a one-stage or two-stage surgery. Several factors must be taken into consideration when making this choice, especially the size and position of the existing tunnels. When the tibial tunnel is semianatomic, it is difficult to make a new tunnel in the correct position without overlapping the existing tunnel. For this reason, we have developed a one-stage ACL revision surgery that uses a bone allograft plug. When it comes to choosing a reconstruction technique, we believe that combined intra-articular and extra-articular reconstruction with the iliotibial band is suitable when the hamstring tendons are not available, combined with clinical findings of translational and rotational instability. Because the existing tunnels require reorientation, a new femoral tunnel can be created by outside-in drilling to eliminate the risk of overlap, while an allograft bone plug can be used to fill the overly anterior tibial tunnel and allow us to drill the correct tibial tunnel right away. In our hands, this is a safe and effective technique, but longer follow-up is needed to validate its indications.

Current and future of anterior cruciate ligament reconstruction techniques

In recent years, anterior cruciate ligament (ACL) reconstruction has generally yielded favorable outcomes. However, ACL reconstruction has not provided satisfactory results in terms of the rate of returning to sports and prevention of osteoarthritis (OA) progression. In this paper, we outline current techniques for ACL reconstruction such as graft materials, double-bundle or single-bundle reconstruction, femoral tunnel drilling, all-inside technique, graft fixation, preservation of remnant, anterolateral ligament reconstruction, ACL repair, revision surgery, treatment for ACL injury with OA and problems, and discuss expected future trends. To enable many more orthopedic surgeons to achieve excellent ACL reconstruction outcomes with less invasive surgery, further studies aimed at improving surgical techniques are warranted. Further development of biological augmentation and robotic surgery technologies for ACL reconstruction is also required.

Knee Ligament Imaging: Preoperative and Postoperative Evaluation

Preoperative and postoperative imaging of knee ligament injury hinges on the appropriate use of available modalities. Knowledge of injury patterns as well as the surgical significance of certain image findings enhances injury detection and supports appropriate preoperative planning. The radiologist must be familiar with the strengths and weaknesses of each modality for evaluating specific aspects of ligamentous pathology. This article focuses on preoperative and postoperative imaging of knee ligament injury. Basic topics pertaining to preoperative image modality selection and isolated injury detection are addressed. More advanced areas including ligamentous injury patterns, surgical indications, and postoperative imaging are also discussed.

Allograft Bone Dowels Show Better Incorporation in Femoral Versus Tibial Tunnels in 2-Stage Revision Anterior Cruciate Ligament Reconstruction: A Computed Tomography-Based Analysis

PURPOSE

The purpose of this study was to quantitatively evaluate the radiographic outcomes of allograft dowels used in 2-stage revision anterior cruciate ligament reconstruction (ACLR) and to compare the incorporation rates of dowels placed in tibial and femoral tunnels.

METHODS

Prospective review of patients who underwent 2-stage revision ACLR with allograft bone dowels. Inclusion criteria were tibial/femoral tunnel diameter of ≥14 mm on preoperative computed tomography (CT) or overlapping of prior tunnels with planned tunnels. Second-stage timing was determined based on qualitative dowel integration on CT obtained at ∼3 months after the first stage. Quantitative analysis of incorporation rates was performed with the union ratio (UR) and occupying ratio (OR) on postoperative CT scans.

RESULTS

Twenty-one patients, with a mean (SD) age of 32.1 (11.4; range, 18-50) years, were included. Second-stage procedures were performed at a mean (SD) of 6.5 (2.1; range, 2.4-11.5) months after first-stage revision. All dowels showed no signs of degradation at the host bone/graft junction at the second-stage procedure. The mean (SD) diameter of the dowels placed in tibial tunnels was greater than those placed in femoral tunnels (16.1 [2.3] mm vs 12.4 [1.6] mm; P < .05). CT was obtained at a mean (SD) of 121 (28; range, 59-192) days after the first-stage surgery. There was no difference between the OR of femoral and tibial tunnels (mean [SD], 87.6% [4.8%] vs 85.7% [10.1%]; P = .484), but the UR was significantly higher in femoral tunnels (mean [SD], 83% [6.2%] vs 74% [10.5%], P = .005). The intraclass correlation coefficients of OR and UR measurements indicated good reliability.

CONCLUSIONS

Allograft bone dowels are a viable graft choice to replenish bone stock in the setting of a staged revision ACL reconstruction. Allograft dowels placed in femoral tunnels had a higher healing union ratio than tibial tunnel allografts and no evidence of degradation at the bone/graft junction, with no difference seen in occupying ratio.

LEVEL OF EVIDENCE

Level IV, case series.

Influence of Preoperative Tunnel Widening On the Outcomes of a Single Stage-Only Approach to Every Revision Anterior Cruciate Ligament Reconstruction: An Analysis of 409 Consecutive Patients From the SANTI Study Group

BACKGROUND

Preoperative tunnel widening is a frequently reported indication for performing a 2-stage revision anterior cruciate ligament reconstruction (ACLR) instead of a single-stage procedure. However, the strength of the available evidence to support a 2-stage strategy is low.

PURPOSE/HYPOTHESIS

The purpose was to evaluate the clinical outcomes of a single stage-only approach to revision ACLR. It was hypothesized that this approach would be associated with significant improvements from baseline in patient-reported outcome measures (PROMs) and knee stability and that there would be no significant differences in any postoperative outcomes between patients with and without preoperative tunnel widening.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective analysis was conducted of a large series of consecutive patients undergoing revision ACLR with a minimum follow-up of 2 years. Preoperative tunnel widening was assessed using digital radiographs. All patients underwent single-stage surgery with an outside-in technique, regardless of the degree of tunnel widening. Clinical outcomes were compared according to whether tunnel widening was present (either tunnel ≥12 mm) or not (both tunnels <12 mm).

RESULTS

The study included 409 patients with a mean ± SD follow-up of 69.6 ± 29.0 months. After revision ACLR, there was a significant reduction in the side-to-side anteroposterior laxity difference, from 7.7 ± 2.2 mm preoperatively to 1.2 ± 1.1 mm at 2 years (P < .001). The mean International Knee Documentation Committee (IKDC) and all subscales of the Knee injury and Osteoarthritis Outcome Score (KOOS) exceeded the thresholds for the Patient Acceptable Symptom State defined for primary ACLR. An overall 358 patients had retrievable preoperative radiographs. According to the tunnel diameter measurements, 111 patients were allocated to group A (both tunnels <12 mm) and 247 patients to group B (either/both tunnels ≥12 mm). There were no significant differences between groups with respect to anteroposterior side-to-side laxity difference, graft rupture rates, non-graft rupture related reoperations, or contralateral anterior cruciate ligament injury rates. There was also no significant difference between groups that exceeded minimal detectable change thresholds for any of the PROMs recorded (ACL-RSI [Anterior Cruciate Ligament-Return to Sports After Injury], Lysholm, Tegner, IKDC, KOOS).

CONCLUSION

A single-stage approach to revision ACLR is associated with excellent clinical results when an outside-in drilling technique is utilized. The presence of preoperative tunnel widening does not significantly influence PROMs, knee stability, graft rupture rates, or non-graft rupture related reoperation rates.

One-Stage Anatomical Revision Anterior Cruciate Ligament Reconstruction: Results According to Tunnel Overlaps

PURPOSE

To present clinical results according to tunnel overlap in 1-stage anatomical revision anterior cruciate ligament reconstruction (ACLR).

METHODS

All patients who underwent revision ACLR performed by a single surgeon (J.H.A.) from 2012 to 2017 and were followed up for >24 months were retrospectively evaluated. The exclusion criteria were concomitant ligament injury, including medial collateral ligament injury, modified Outerbridge grade ≥3 cartilage lesion, and severe meniscus defects. Tunnel overlap was measured on 3-dimensionally reconstructed computed tomography images. Patients in the nonoverlapped femoral tunnel group (group NO, n = 52) were treated with new tunnel drilling that completely avoided previous tunnels, and those in the overlapped femoral tunnel group (group O, n = 41) were treated with a new tunnel that overlapped with previous tunnels. Clinical outcomes were evaluated using the subjective International Knee Documentation Committee (IKDC) and Lysholm scores. Knee joint stability was measured using the Lachman and pivot shift tests. Patients with femoral tunnel widening of ≥14 mm underwent 2-stage ACLR.

RESULTS

The mean follow-up duration of 93 patients was 46.9 months (range, 24-97 months). All preoperative subjective and objective IKDC (P<0.001) and Telos stress test scores (P = .016) were significantly improved at the last follow-up. Forty-one patients had overlapping femoral tunnels, whereas 87 had overlapping tibial tunnels. At the last follow-up, subjective IKDC and Lysholm scores (73.6 ± 15.3 vs 74.9 ± 12.1, P = .799 and 80.0 ± 19.2 vs 81.44 ± 13.5, P = .505, respectively) and objective pivot shift (IKDC grade) in the Lachman test (P = .183 and P = .450, respectively) did not differ significantly between groups NO and O, respectively.

CONCLUSIONS

One-stage anatomical revision ACLR significantly improved the clinical results. Most tibial tunnels (94%) and approximately one-half (44%) of the femoral tunnels overlapped. The overlapped femoral tunnel group did not show inferior outcomes or stability.

LEVEL OF EVIDENCE

Level III, cohort study.

Economic Reliable Technique for Tunnel Grafting Using Iliac Crest Bone Graft in Two-Staged Revision Anterior Cruciate Ligament Surgery

Revision anterior cruciate ligament surgery is a technically demanding procedure. Mal-positioned tunnels together with bone loss and its management are some of the difficulties and challenges faced. Two-staged procedures have successfully been used to tackle those challenges. We present a technique that is safe, reliable, reproducible, and economic in the management of bone defects faced in anterior cruciate ligament revision surgery by using iliac crest bone graft. Preoperative assessment of tunnel position and size is done by computed tomography. Tri-cortical iliac crest bone graft is harvested through a trap door. It is then shaped to fit the tunnels to be filled. It is tapered at the advancing end to facilitate introduction. Mounted on a passing pin and a drill bit, the graft is arthroscopically introduced into the femoral and tibial tunnels. The second stage is performed after the graft has incorporated, as seen on postoperative computed tomography, done at approximately 3 months after the first stage. Iliac crest provides a natural abundant reservoir for bone graft and has all the advantages of being an autograft. With good meticulous technique, complications can be avoided with less donor-site morbidity. This technique is safe, reliable, and reproducible. It provides an ample amount of graft and harvest does not rely on implants; hence, it is economic.

Lipoteichoic Acid Accelerates Bone Healing by Enhancing Osteoblast Differentiation and Inhibiting Osteoclast Activation in a Mouse Model of Femoral Defects

Lipoteichoic acid (LTA) is a cell wall component of Gram-positive bacteria. Limited data suggest that LTA is beneficial for bone regeneration in vitro. Thus, we used a mouse model of femoral defects to explore the effects of LTA on bone healing in vivo. Micro-computed tomography analysis and double-fluorochrome labeling were utilized to examine whether LTA can accelerate dynamic bone formation in vivo. The effects of LTA on osteoblastogenesis and osteoclastogenesis were also studied in vitro. LTA treatment induced prompt bone bridge formation, rapid endochondral ossification, and accelerated healing of fractures in mice with femoral bone defects. In vitro, LTA directly enhanced indicators of osteogenic factor-induced MC3T3-E1 cell differentiation, including alkaline phosphatase activity, calcium deposition and osteopontin expression. LTA also inhibited osteoclast activation induced by receptor activator of nuclear factor-kappa B ligand. We identified six molecules that may be associated with LTA-accelerated bone healing: monocyte chemoattractant protein 1, chemokine (C-X-C motif) ligand 1, cystatin C, growth/differentiation factor 15, endostatin and neutrophil gelatinase-associated lipocalin. Finally, double-fluorochrome, dynamic-labeling data indicated that LTA significantly enhanced bone-formation rates in vivo. In conclusion, our findings suggest that LTA has promising bone-regeneration properties.

Cancellous allogenic and autologous bone grafting ensure comparable tunnel filling results in two-staged revision ACL surgery

OBJECTIVES

Patients with recurrent instability after anterior cruciate ligament (ACL) reconstruction often present with enlarged or misplaced tunnels and bone grafting is required prior to the actual revision reconstruction. Autologous bone grafting features limited quantity and donor site morbidity. These problems may be eliminated utilizing cancellous bone allografts, but their efficiency and reliability have not been investigated systematically. The aim of the present study was to compare tunnel filling rates attained by utilizing either allogenic or autologous cancellous bone grafts.

MATERIALS AND METHODS

A total of 103 consecutive patients were enrolled retrospectively. All patients suffered from recurrent instability and underwent either allogenic or autologous cancellous bone grafting. Computed tomography (CT) was carried out before and after the bone grafting procedure. Based on preoperative CT scans, positioning and maximum diameter of the femoral and tibial tunnels were determined. Tunnel filling rates were calculated as a ratio of pre- and postoperative tunnel volumes. Primary outcome was the tibial tunnel filling rate. Femoral filling rates and density of the grafted bone were assessed secondarily.

RESULTS

Preoperative CT scans revealed no significant differences between the two groups regarding distribution of misplacement and widening of the femoral or tibial tunnel. Postoperative CT scans were conducted after an interval of 5.2 months. Tunnel filling rates of 74.5% (± 14.3) femoral and 85.3% (± 10.3) tibial were achieved in the allogenic compared to 74.3% (± 15.9) femoral and 84.9% (± 9.4) tibial in the autologous group. With p values of 0.85 at the femur and 0.83 at the tibia, there were no significant differences between the groups. The density of the grafted bone revealed significantly higher values in the allogenic group.

CONCLUSIONS

Utilizing cancellous bone allografts in two-staged revision ACL surgery provides for sufficient and reproducible filling of enlarged or misplaced tunnels. The filling rates are comparable to those achieved with autologous bone grafting. Advantages of allografts are the unrestricted quantity and the absence of any harvesting procedure.

Editorial Commentary: Bone Tunnel Grafting for Two-Stage Anterior Cruciate Ligament Revision and the Meaning of Life for an Arthroscopic Surgeon

Accurate bone tunnel filling in a 2-staged anterior cruciate ligament revision is indubitably fundamental for a successful outcome. Bone autograft is commonly employed and it is usually harvested from the iliac crest: this requires longer surgical time, and donor-site morbidity following bone harvest is a well-known problem. Therefore, strategies to minimize or abolish it have been attempted: the use of allografts may seem promising, but their use is associated with high costs and strict regulatory limitations. Bony substitutes instead represent a new and potentially effective solution: they could help surgeons to fill bone tunnels in an easier and faster way that elicits satisfactory lamellar bone formation within the tunnels, and their use is associated with fewer postoperative complications, such as pain and local hematoma. Evidence from literature suggests that this approach could provide significant advantages over traditional autograft harvesting, with comparable outcomes in terms of bone formation and integration, allowing a correct tunnel placement during revision surgery.