Revision anterior cruciate ligament reconstruction

One-stage revision anterior cruciate ligament reconstruction: Preoperative evaluation, planning and surgical techniques. A review of current concepts

The increased rate of anterior cruciate ligament (ACL) tears has led to a greater number of revisions. Revision surgery can be performed in one or two stages. Single-stage revision ACL reconstruction (ssRACLR) may be performed when prior tunnels can be re-used or bypassed whereas a two-stage procedure is indicated when bone grafting of dilated tunnels prior to revision is necessary. While both approaches have shown similar functional outcomes and failure risk, ssRACLR is preferred, when possible, to avoid the increased morbidity, inconvenience and cost associated with two-stage RACLR. In adequately planning for RACLR, a surgeon should investigate the mechanism and timing of injury as well as the previous graft selection, associated pathology and the tunnel placement and size. It is especially important to obtain radiographs and three-dimensional imaging including magnetic resonance imaging (MRI) and computed tomography (CT), which allow the surgeon to accurately evaluate the entire tunnel architecture to determine surgical staging. Following a detailed assessment of the pathoanatomy, the surgeon may determine graft and hardware type, tunnel placement and utilization of lateral extra-articular tenodesis (LET) and other procedures. In our experience, ssRACLR can be carried out for over 90% of revision cases with creative pre-operative planning using autograft with bone plug(s), divergent tunnel creation on the femur (when necessary) and convergent tunnel creation on the tibia (when appropriate) and suspensory or interference fixation as needed. In revision scenarios, we believe that autografts with bone plugs provide the best opportunity for graft healing and incorporation and that LET can be a useful adjunct to reduce re-tear rates. The purpose of this review is to report on the preoperative considerations and surgical techniques for performing ssRACLR, as well as the outcomes.

Level of Evidence

Level V expert opinion.

Ligamental reconstruction improved the functional outcomes of patients with anterior cruciate ligament injury and early-stage symptomless osteoarthritis

BACKGROUND

The optimal treatment for anterior cruciate ligament (ACL) injuries with early-stage symptomless osteoarthritis (OA) remains unclear. This study aimed to compare the clinical outcomes of ACL reconstruction (ACLR) in patients with ACL injury in the presence and absence of early-stage symptomless OA.

METHODS

Medical records of patients with early-stage symptomless OA who sustained ACL injury and underwent ACLR from January 2018 to December 2020 at a single institution were retrospectively reviewed. Radiography and magnetic resonance imaging were performed preoperatively to identify ACL injury and OA. Patients with ACL injury and early-stage symptomless OA (combined group, n = 14) were matched at a 1:2 ratio with patients with ACL injury (isolated group, n = 32). Data on demographic characteristics, pain and functional outcomes (visual analogue scale, Tegner, Lysholm, and International Knee Documentation Committee scores and range of motion), and imaging outcomes were collected. Complications were recorded, and outcomes were compared between the groups.

RESULTS

Forty-six patients (26 males, 20 females) were included in this study, among whom 14 had ACL injury and early-stage symptomless OA, whereas 32 sustained isolated ACL injury (average follow-up duration: 3.4 ± 1.0 years). At the final follow-up, pain and functional outcomes similar to those in patients with isolated ACL-deficient knees were achieved in the combined group; acute-stage ACLR resulted in significantly better outcomes (p < 0.05). No significant radiographic progression of OA or complications were observed.

CONCLUSIONS

Knee function in patients with ACL injuries and early-stage symptomless OA who underwent ACLR was the same as that in patients with isolated ACL-deficient knees. Furthermore, ACLR had a beneficial effect on knee outcomes. The subgroup analysis revealed that acute-stage ACLR could lead to better outcomes in patients with ACL injuries and early-stage symptomless OA.

Modifiable and non-modifiable risk factors affecting surgical failure after revision ACL reconstruction: a cohort study

BACKGROUND

Research on factors influencing the outcomes of revision anterior cruciate ligament (ACL) reconstruction is relatively scarce and mostly relies even on reports from a single group. Understanding the factors contributing to the failure of revision ACL reconstruction can provide valuable information for achieving better clinical outcomes and assist in patient counseling before surgery. Therefore, this study aimed to analyze the factors contributing to surgical failure after revision ACL reconstruction.

METHODS

The medical records of consecutive patients who underwent single-bundle revision ACL reconstruction using the transportal technique between 2010 and 2020 and had a minimum follow-up of 2 years were retrospectively reviewed. Eligible patients were classified into two groups on the basis of the presence of surgical failure during the follow-up period (group NF, patients who did not experience surgical failure; group F, patients who experienced surgical failure). In this study, surgical failure after revision ACL reconstruction was defined as meeting any of the following conditions during follow-up: the presence of graft re-tear confirmed by magnetic resonance imaging (MRI), anterior-posterior laxity graded ≥ 2, or rotational laxity graded ≥ 2. A comparative analysis was conducted on demographic data, as well as peri-, intra-, and postoperative data between the groups. Additionally, a regression analysis was performed to investigate factors influencing surgical failure after revision ACL reconstruction.

RESULTS

A total of 58 patients were included (group NF, 40 patients; group F, 18 patients). In between-group comparisons of demographic, peri-, and intra-operative data, group F exhibited a higher frequency of multiple revision surgeries (P = 0.001), increased preoperative osteoarthritis grade (P = 0.001), and shallower femoral tunnel depth (P = 0.002) compared with group NF. At the final follow-up, group F demonstrated relatively poor clinical outcomes, both subjectively and objectively. Multivariate regression analysis revealed that all variables that showed differences in the preceding comparisons were independent factors affecting surgical failure after revision ACL reconstruction.

CONCLUSIONS

Surgical failure after revision ACL reconstruction can occur in a substantial number of patients, influenced by non-modifiable factors, such as cases corresponding to multiple revision surgery and preoperative osteoarthritis grade, and modifiable factors, such as femoral tunnel depth.

Exosome-Integrated Hydrogels for Bone Tissue Engineering

Exosome-integrated hydrogels represent a promising frontier in bone tissue engineering, leveraging the unique biological properties of exosomes to enhance the regenerative capabilities of hydrogels. Exosomes, as naturally occurring extracellular vesicles, carry a diverse array of bioactive molecules that play critical roles in intercellular communication and tissue regeneration. When combined with hydrogels, these exosomes can be spatiotemporally delivered to target sites, offering a controlled and sustained release of therapeutic agents. This review aims to provide a comprehensive overview of the recent advancements in the development, engineering, and application of exosome-integrated hydrogels for bone tissue engineering, highlighting their potential to overcome current challenges in tissue regeneration. Furthermore, the review explores the mechanistic pathways by which exosomes embedded within hydrogels facilitate bone repair, encompassing the regulation of inflammatory pathways, enhancement of angiogenic processes, and induction of osteogenic differentiation. Finally, the review addresses the existing challenges, such as scalability, reproducibility, and regulatory considerations, while also suggesting future directions for research in this rapidly evolving field. Thus, we hope this review contributes to advancing the development of next-generation biomaterials that synergistically integrate exosome and hydrogel technologies, thereby enhancing the efficacy of bone tissue regeneration.

Preservation of the MMPH and Status of the Notch Configurations Are Important Factors for Successful Revision ACL Reconstruction

OBJECTIVE

The aim of this study was to identify the differences in anatomical factors between the patients who underwent revision and primary anterior cruciate ligament reconstructions (ACLR) and compare the outcomes between the 2 surgeries.

DESIGN

Retrospective cohort study.

SETTING

Single institution tertiary academic center between 2014 and 2020.

PATIENTS

A total of 84 matched patients who underwent revision (group I) or primary ACLR (group II).

INTERVENTIONS

Radiological evaluations were performed using side-to-side differences (SS-D), femorotibial angle, and posterior tibial slope. The medial meniscus posterior horn status as width (MMPHW), medial tibial plateau width (MTPW), notch configurations, tunnel positions, and sagittal graft angle were measured using 3D-CT and magnetic resonance imaging (MRI).

MAIN OUTCOME MEASURES

Graft signals were assessed using MRI. The clinical outcomes were assessed.

RESULTS

Group I showed larger SS-D and higher mean Howell grade of anterior cruciate ligament (ACL) graft than group II ( P = 0.002 and P = 0.004, respectively). Multivariate regression analyses showed that the decreased MMPHW/MTPW ratio ( P = 0.010) and notch width index ( P < 0.007) were significantly independent factors associated with the higher Howell grade of ACL grafts. The decreased MMPHW/MTPW ratio ( P < 0.001) was a significantly independent factor associated with larger SS-D. In the subgroup analysis, all patients in the notchplasty group showed wider notches postoperatively ( P < 0.001).

CONCLUSIONS

Revision ACLRs resulted in worse ACL signal intensity and stability outcome. The results of this study suggest that it may be important to preserve the MMPHW as much as possible and check notch configurations, especially during a revision ACLR.

Four-year comparative analysis of return to sport and psychological recovery following ACL revision: Artificial ligament vs. anterior tibial tendon allograft

Background

Research on return to sport and psychological recovery in anterior cruciate ligament (ACL) revision remains scarce. The clinical efficacy of artificial ligament in ACL revision requires further exploration. Our objectives were (1) to compare the midterm clinical outcomes of artificial ligament versus allogenic tendon graft in ACL revision and (2) to analyze the effects of employing artificial ligament on return to sport and psychological recovery in ACL revision.

Methods

This cohort study included the cases receiving ACL revision from 2014 to 2021 in Sports Medicine Department of Huashan Hospital. The grafts used were Ligament Advanced Reinforcement System (LARS) and ATT allograft. We recorded patients' baseline data. The final follow-up assessment included subjective scales, physical examination, and return to sport status. We recorded the rates and timings of return to sport. Subjective scales included the 2000 International Knee Documentation Committee (IKDC) subjective score, Lysholm Knee Scaling Score (LKSS), Knee injury and Osteoarthritis Outcome Score (KOOS), Tegner activity score, Marx activity rating score, and Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI). Anterior knee stability was assessed using the KT-1000 arthrometer.

Results

Fifty cases (LARS group: 27; ATT group: 23) enrolled and 45 (LARS group: 23; ATT group: 22) completed evaluations with a median follow-up period of 49 months. At recent follow-up, LARS group outperformed in knee stability (1.0 ± 1.9 mm vs. 2.6 ± 3.0 mm, P = 0.039), confidence (86.7 ± 12.4 vs. 69.4 ± 18.6, P < 0.001), emotion (82.7 ± 11.3 vs. 70.7 ± 16.2, P < 0.001), KOOS knee function (78.7 ± 8.8 vs. 69.5 ± 11.0, P = 0.003), quality of life (79.1 ± 16.1 vs. 66.4 ± 19.5, P = 0.014), Tegner score (6.3 ± 1.9 vs. 5.2 ± 2.1, P < 0.001), and Marx activity score (10.7 ± 3.7 vs. 7.9 ± 4.0, P = 0.012). The LARS group had significantly higher return rates: recreational (91.3 % vs. 63.6 %, P = 0.026), knee cutting and pivoting (87.0 % vs. 59.1 %, P = 0.035), competitive (78.3 % vs. 45.5 %, P = 0.023), and pre-injury (56.5 % vs. 27.3 %, P = 0.047). For return timings, the LARS group was earlier at recreational (11.2 ± 3.9 vs. 27.8 ± 9.0 weeks, P < 0.001), knee cutting and pivoting (17.2 ± 5.8 vs. 35.6 ± 13.8 weeks, P < 0.001), competitive (24.8 ± 16.2 vs. 53.2 ± 22.0 weeks, P < 0.001), and pre-injury levels (32.8 ± 11.0 vs. 72.8 ± 16.9 weeks, P < 0.001).

Conclusion

In ACL revision, using LARS demonstrated improved joint stability and functionality compared to using allogenic ATT four years postoperative. Patients accepting the LARS procedure exhibited higher rates and earlier timings of return to various levels of sport, indicating enhanced confidence and emotional resilience.

The translational potential of this article

In ACL revision, the choice of artificial ligament to shorten recovery time, thereby enabling patients to return to sport more quickly and effectively, is thought-provoking. The research value extends beyond mere graft selection, guiding future clinical trials and studies. This research enhances our understanding of the application value of artificial ligament in ACL revision, emphasizing the importance of psychological recovery and updating our perceptions of return to sport levels post-revision. It stimulates exploration into personalized rehabilitation programs and treatment strategies, aiming to optimize clinical outcomes and meet the real-world needs of patients with failed ACL reconstruction.

Revision Anterior Cruciate Ligament Reconstruction and Associated Procedures

Failure of anterior cruciate ligament reconstruction (ACLR) is a common yet devastating complication due to inferior clinical outcomes associated with revision ACLR. Identifying the cause and associated risk factors for failure is the most important consideration during preoperative planning. Special attention to tunnel quality, concomitant injuries, and modifiable risk factors will help determine the optimal approach and staging for revision ACLR. Additional procedures including lateral extra-articular tenodesis and osteotomy may be considered for at-risk populations. The purpose of this review is to explore causes of ACLR failure, clinical indications and appropriate patient evaluation, and technical considerations when performing revision ACLR.

Revision ACL reconstruction in female athletes: current concepts

The challenge of revision anterior cruciate ligament (ACL) reconstruction lies in its complexity, varied presentation, and technical intricacies. A successful ACL reconstruction should allow patients to safely return to preinjury activities. However, it is only sometimes simple, and many risk factors and concurrent pathologies come into play. Evaluating and analysing the cause of failure and associated conditions is paramount to addressing them effectively. Despite a plethora of research and improvements in knowledge and technology, e gaps exist in issues such as optimal techniques of revision surgery, graft options, fixation, concurrent procedures, rehabilitation and protocol for return to sports of high-level athletes. Female athletes need additional focus since they are at higher risk of re-injury, suboptimal clinical outcomes, and lower rates of return to sport following revision reconstruction. Our understanding about injury prevention and the protection of ACL grafts in female athletes needs to be improved. This review focuses on the current state of revision ACL surgery in female athletes and provides recommendations and future directions for optimising outcomes in this high-risk group.

Complex Anterior Cruciate Ligament Revision and Lateral Extra-Articular Tenodesis With Achilles Tendon Allograft: The "Monoloop" Technique

Revision of anterior cruciate ligament reconstruction (ACL-R) presents many challenges that are not encountered in the primary setting and, therefore, requires thorough preoperative planning. Recently, there has been growing evidence showing that combining the anterolateral ligament (ALL) reconstruction with ACL-R revision reduces the risk of postoperative ACL rupture and meniscal tears, and therefore, the ALL reconstruction becomes essential to a complex ACL revision. The technique that we describe is mainly used in the setting of complex ACL revision with extensive tunnel osteolysis associated with rotational instability of the knee. This article presents a technique for a one-stage complex ACL-R revision combined with ALL reconstruction using an Achilles tendon allograft with a bone plug.

Autograft Demonstrates Superior Outcomes for Revision Anterior Cruciate Ligament Reconstruction When Compared With Allograft: A Systematic Review

BACKGROUND

Multiple studies have compared outcomes among patients undergoing revision anterior cruciate ligament reconstruction (ACLR) with autograft versus allograft, but these data are inconsistently reported and long-term outcomes depending on graft type are yet to be determined.

PURPOSE

To perform a systematic review of clinical outcomes after revision ACLR (rACLR) with autograft versus allograft.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review of the literature was performed by searching PubMed, the Cochrane Library, and Embase to identify studies that compared the outcomes of patients undergoing rACLR with autograft versus allograft. The search phrase used was autograft allograft revision anterior cruciate ligament reconstruction. Graft rerupture rates, return-to-sports rates, anteroposterior laxity, and patient-reported outcome scores (subjective International Knee Documentation Committee, Tegner, Lysholm, and Knee injury and Osteoarthritis Outcome Score) were evaluated.

RESULTS

Eleven studies met inclusion criteria, including 3011 patients undergoing rACLR with autograft (mean age, 28.9 years) and 1238 patients undergoing rACLR with allograft (mean age, 28.0 years). Mean follow-up was 57.3 months. The most common autograft and allograft types were bone-patellar tendon-bone grafts. Overall, 6.2% of patients undergoing rACLR experienced graft retear, including 4.7% in the autograft group and 10.2% in the allograft group (P < .0001). Among studies that reported return-to-sports rates, 66.2% of patients with an autograft returned to sports as opposed to 45.3% of patients with an allograft (P = .01). Two studies found significantly greater postoperative knee laxity in the allograft group as compared with the autograft group (P < .05). Among all patient-reported outcomes, 1 study found 1 significant difference between groups: patients with an autograft had a significantly higher postoperative Lysholm score when compared with patients with an allograft.

CONCLUSION

Patients undergoing revision ACLR with an autograft can be expected to experience lower rates of graft retear, higher rates of return to sports, and less postoperative anteroposterior knee laxity when compared with patients undergoing revision ACLR with an allograft.

PEEK Interference Screws Show Significant Tunnel Enlargement After ACL Reconstruction and is Comparable to Adjustable-Length Loop Cortical Button Fixation

Background

It is unclear whether the use of polyetheretherketone (PEEK) interference screws for anterior cruciate ligament (ACL) reconstruction leads to postoperative tunnel enlargement. Femoral tunnel enlargement was further compared with adjustable-length loop cortical fixation.

Methods

Eighteen patients with ACL reconstruction using hamstring grafts were retrospectively divided into two groups. Eleven patients were treated with the ACL reconstruction technique using a PEEK interference screw for femoral graft fixation. Seven patients received adjustable-length loop cortical buttons for femoral fixation. Tibial ACL graft fixation was performed using PEEK interference screws. Tunnel volume changes were assessed using computed tomography (CT) scans performed after surgery (100%) and after 1 year. The maximal tunnel diameter was measured.

Results

The group with femoral screw fixation showed a mean tunnel volume change of 108.15 ± 13.7% on the tibial side and 124.07 ± 25.38% on the femoral side. The group with femoral button fixation showed a tunnel volume change of 111.12 ± 12.72% on the tibial side and 130.96 ± 21.71% on the femoral side. The differences in femoral tunnel volume changes were not significant (P = 0.562). Femoral tunnels with PEEK screw fixation showed significantly larger diameter after 12 months in comparison with button fixation (13.02 ± 1.43 mm vs. 10.46 ± 1.29 mm, P < 0.001).

Conclusions

PEEK interference screws were associated with significant tibial and femoral tunnel enlargement. Femoral tunnel enlargement was comparable between PEEK interference screws and button fixation. Final femoral tunnel diameter was significantly larger with PEEK screw fixation in comparison to button fixation.

Anteromedial Portal versus Transtibial Drilling Techniques for Femoral Tunnel Placement in Arthroscopic Anterior Cruciate Ligament Reconstruction: Radiographic Evaluation and Functional Outcomes at 2 Years Follow-Up

The aim of this study was to compare the functional and radiographic outcomes of arthroscopic single-bundle anterior cruciate ligament reconstruction (ACLR) using either the anteromedial (AM) portal technique or transtibial (TT) technique. We identified 404 patients who underwent arthroscopic ACLR by a single surgeon between January 2006 and December 2016 at our institution. The TT portal was utilized in femoral tunnel drilling in 202 patients (TT group) while the AM portal was used in 202 patients (AM group). The mean postoperative follow-up duration was 26 months (range: 24-33 months). Postoperative radiographic femoral and tibial tunnel positions were assessed by two independent observers. Functional outcomes were evaluated with Tegner, Lysholm, and Knee Injury and Osteoarthritis Outcome score (KOOS) scores. On the anteroposterior plain radiographs, the mean femoral tunnel position relative to the lateral femoral condyle was 46.8% for the AM group versus 48.6% in the TT group, respectively (p=0.003). The mean graft inclination angle was 31.9° and 22° in the AM and TT groups, respectively (p<0.0001). On the lateral radiographs, the mean femoral tunnel placement across Blumensaat's line in relation to the anterior femoral cortex was 84% in the AM group while it was 78% in the TT group (p<0.0001). At 2 years postoperatively, there were no significant differences in the mean Tegner, Lysholm, and KOOS scores between the two patient groups. The graft failure rate at 2 years follow-up was 4.5% (n=9) in the AM group while it was 2.5% (n=5) in the TT group (p=0.2). Femoral tunnel placement was more anatomical with the AM portal technique compared with the TT technique. However, there was no significant difference in postoperative functional outcomes between the two patient groups. The AM portal technique appears to have a higher graft failure rate. This might be attributed to increased graft loading in an anatomical position.

Association Between Posterior Tibial Slope and Clinical Outcomes After Isolated Anterior Cruciate Ligament Reconstructions

Background Increased posterior tibial slope (PTS) is an important risk factor for non-traumatic graft failure and revision surgery after anterior cruciate ligament reconstruction. If a tibial posterior slope is an important factor for graft failure after anterior cruciate ligament reconstruction, does it affect clinical outcomes? This study aimed to evaluate the association between PTS and clinical outcomes after anterior cruciate ligament reconstruction. Material and methods Patients undergoing arthroscopic anterior cruciate ligament reconstruction with hamstring tendons in the clinic were evaluated retrospectively. Inclusion criteria were: patients with at least an 18-month follow-up period who were evaluated with the Tegner Lysholm scoring system, aged between 18 and 40 years, with only an anterior cruciate ligament rupture. PTSs were measured from the lateral radiographs of the knees. The patients were divided into two groups with a PTS of 10° or less. Results The mean Tegner Lysholm score was 86.8 ± 8.9. The mean PTS was 9.7° ± 1.5°. In total, 14 and 15 patients had a PTS of above 10° and below 10°, respectively. The mean age and follow-up time of patients were 28.5 ± 5.3 years and 24.6 ± 7.2 months in the group with a PTS of above 10° and 30.2 ± 5.3 years and 24.2 ± 5.18 months in the group with a PTS of below 10°, respectively. Tegner Lysholm scores were 88.2 ± 8.8 and 85.6 ± 9.1 in the group with values above 10° and below 10°, respectively. Statistically, there was no significant difference between the clinical outcomes of both groups. Conclusion PTS does not affect the clinical outcomes of patients who underwent arthroscopic anterior cruciate ligament reconstruction in the early period.

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.

Rotational stability can be enhanced in revision anterior cruciate ligament reconstruction using the over-the-top augmentation technique compared to single bundle technique

PURPOSE

Revision anterior cruciate ligament (ACL) reconstruction is technically challenging due to mispositioned tunnels, bone loss, and tunnel enlargement, which may compromise graft fixation and result in failure. To obtain firm graft fixation and strength in one stage, we utilized an over-the-top augmentation technique using an Achilles tendon allograft in revision ACL reconstruction (OA-ACLR). This study compared OA-ACLR with single-bundle ACL reconstruction (SB-ACLR). We hypothesized that OA-ACLR would enhance the postoperative knee joint rotational stability.

METHODS

We retrospectively analyzed 47 patients who underwent revisional OA-ACLR and 48 who underwent primary SB-ACLR with minimum follow-up of 6 months. Knee instability was evaluated with the anterior drawer, Lachman, and pivot shift tests preoperatively and at the final follow-up. Side-to-side differences were compared with the non-affected side at the final follow-up. Function was evaluated using the IKDC subjective and Lysholm knee scores preoperatively and at the final follow-up.

RESULTS

The groups did not differ in terms of sex, age, BMI, and etiology. There were no significant differences in concomitant surgical procedures, such as meniscectomy and meniscus repair, between the two groups (p = 0.335, > 0.99). Both groups significantly improved in the anterior drawer, Lachman, pivot shift tests, and IKDC and Lysholm knee scores after surgery (all p < 0.001). The OA-ACLR group showed significantly higher rotational stability in the pivot shift test than the SB-ACLR group (p = 0.017). The postoperative side-to-side difference, the IKDC and Lysholm scores showed no significant differences between the groups (p = 0.34, 0.301, 0.438).

CONCLUSIONS

OA-ACLR showed enhanced rotational stability with pivot shift test compared to SB-ACLR. It may be considered a useful alternative for revision ACL reconstruction.

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.

More anterior placement of femoral tunnel position in ACL-R is associated with postoperative meniscus tears

PURPOSE

The purpose of this study was to investigate the relationship between tunnel position in ACL reconstruction (ACL-R) and postoperative meniscus tears.

METHODS

This was a single institution, case-control study of 170 patients status-post ACL-R (2010-2019) separated into two matched groups (sex, age, BMI, graft type). Group 1-symptomatic, operative meniscus tears (both de novo and recurrent) after ACL-R. Group 2-no postoperative meniscus tears. Femoral and tibial tunnel positions were measured by 2 authors via lateral knee radiographs that were used to measure two ratios (a/t and b/h). Ratio a/t was defined as distance from the tunnel center to dorsal most subchondral contour of the lateral femoral condyle (a) divided by total sagittal diameter of the lateral condyle along Blumensaat's line (t). The ratio b/h was defined as distance between the tunnel and Blumensaat's line (b) divided by maximum intercondylar notch height (h). Wilcoxon sign-ranks paired test was used to compare measurements between groups (alpha set at p < 0.05).

RESULTS

Group 1 had average follow up of 45 months and Group 2 had average follow up of 22 months. There were no significant demographic differences between Groups 1 and 2. Group 1-a/t was 32.0% (± 10.2), which was significantly more anterior than group 2, 29.3% (± 7.3; p < 0.05). There was no difference in average femoral tunnel ratio b/h or tibial tunnel placement between groups.

CONCLUSIONS

A relationship exists between more anterior/less anatomic femoral tunnel position and the presence of recurrent or de novo, operative meniscus tears after ACL-R. Surgeons performing ACL-R should strive for recreation of native anatomy via proper tunnel placement to maximize postoperative outcomes.

LEVEL OF EVIDENCE

Level III.

New Considerations in ACL Surgery: When Is Anatomic Reconstruction Not Enough?

➤ Clinicians should be careful to assess for associated injuries including anterolateral complex and medial meniscal ramp lesions or lateral meniscal posterior root tears.➤ Consideration of lateral extra-articular augmentation should be given for patients with >12° of posterior tibial slope.➤ Patients with preoperative knee hyperextension (>5°) or other nonmodifiable risk factors, including high-risk osseous geometry, may benefit from a concomitant anterolateral augmentation procedure to improve rotational stability.➤ Meniscal lesions should be addressed at the time of anterior cruciate ligament reconstruction with meniscal root or ramp repair.

Remnant Preservation of the Primary Vertical Graft in Revision Anterior Cruciate Ligament Reconstruction

Background

The remnant preservation of a primary vertical graft in revision anterior cruciate ligament reconstruction (ACLR) can benefit anteroposterior stability. However, studies that address this concept are rare.

Purpose

To evaluate clinical outcomes of remnant preservation of primary vertical graft in revision ACLR.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 74 patients with revision ACLR were included in this retrospective study. Remnant preservation revision ACLR was performed only in patients with primary vertical grafts. The patients were divided into 2 groups according to whether the primary remnant vertical graft was preserved (remnant group; n = 48) or absent or sacrificed (no-remnant group; n = 26). The remnant group was further divided according to the degree of remnant tissue: sufficiently preserved subgroup (graft coverage, ≥50%; n = 25) and insufficiently preserved subgroup (graft coverage, <50%; n = 23). Clinical outcomes were evaluated using the International Knee Documentation Committee (IKDC) subjective form, Lysholm score, Tegner activity scale, manual laxity tests, and side-to-side difference in anterior tibial translation on Telos stress radiographs.

Results

The mean time to final follow-up was 40.7 ± 16.8 months. The remnant group showed more improved results in the postoperative Lachman test and Telos side-to-side difference than did the no-remnant group (P = .017 and .016, respectively). The post hoc test revealed that the side-to-side difference in laxity in the sufficiently preserved subgroup significantly outperformed that in the no-remnant group (P = .001), although no significant difference existed between the insufficiently preserved and no-remnant subgroups (P = .850). The postoperative IKDC subjective form, Lysholm score, and Tegner activity scale did not show significant differences between the 2 groups (P = .480, .277, and .883, respectively).

Conclusion

The remnant preservation of the primary vertical graft in revision ACLR may result in better anteroposterior stability. However, subjective outcomes in the remnant group did not exceed that of the no-remnant group. The subgroup analysis revealed that only sufficiently preserved remnants demonstrated better anteroposterior stability.

Re-injury after arthroscopic anatomical reconstruction of the lateral ankle ligaments treated by a new arthroscopic anatomical reconstruction: A case report

INTRODUCTION AND IMPORTANCE

Lateral ankle ligament reconstruction failures are increasingly frequent. To our knowledge no reports of using a new arthroscopic anatomical reconstruction with a gracilis autograft to treat an ankle re-injury have been described.

CASE PRESENTATION

A 19-year-old man presented with a right ankle injury resulting in isolated lateral ankle instability. The clinical examination showed significant laxity. The MRI confirmed a grade 3 tear of the lateral ligament complex. Arthroscopic anatomical reconstruction with a gracilis autograft was performed and the patient was able to return to all of his activities. Eighteen months after the primary reconstruction, he had another high-energy injury. Despite rehabilitation, he experienced isolated lateral instability. Arthrography confirmed graft failure. The patient underwent a new anatomical reconstruction with the controlateral gracilis autograft, with no difficulties. At 6 months, he had returned to all of his activities, with no limitations or discomfort.

CLINICAL DISCUSSION

Articular hypermobility, hindfoot varus and/or excess weight should be looked for or treated to explain the graft failure. Other therapeutic options are possible for revision surgery such as non-anatomical tenodesis, allografts or artificial ligaments.

CONCLUSION

Arthroscopic anatomical reconstruction of the lateral ligaments of the ankle with a new arthroscopic anatomical reconstruction procedure seems to be feasible. Other studies are needed to define the therapeutic strategy for ligament reconstruction graft failures.

Impact of Occupation on 12-Month Outcomes After Anterior Cruciate Ligament Reconstruction in Male Patients

Background

The impact of a physically demanding occupation on clinical outcomes after anterior cruciate ligament (ACL) reconstruction (ACLR) is largely unknown.

Purpose/Hypothesis

The purpose of this study was to assess the influence of occupation on 12-month outcomes after ACLR in male patients. It was hypothesized that patients undertaking manual work would not only have better functional outcomes in terms of strength and range of motion but also higher rates of joint effusion and greater anterior knee laxity.

Study Design

Cohort study; Level of evidence, 3.

Methods

From an initial cohort of 1829 patients, we identified 372 eligible patients aged 18 to 30 years who underwent primary ACLR between 2014 and 2017. Based on a preoperative self-assessment, 2 groups were established: patients engaged in heavy manual occupations and those engaged in low-impact occupations. Data were collected from a prospective database including effusion, knee range of motion (using side-to-side difference), anterior knee laxity, limb symmetry index for single hop and triple hop, International Knee Documentation Committee (IKDC) subjective score, and complications up to 12 months. Because of the significantly lower rate of female patients undertaking heavy manual occupations compared to low-impact occupations (12.5% and 40.0%, respectively), data analysis was focused on male patients. Outcome variables were assessed for normality, and statistical comparisons were made between the heavy manual and low-impact groups using either an independent-samples t test or the Mann-Whitney U test.

Results

Of 230 male patients, 98 were included in the heavy manual occupation group, and 132 were included in the low-impact occupation group. Patients in the heavy manual occupation group were significantly younger than those in the low-impact occupation group (mean age, 24.1 vs 25.9 years, respectively; P < .005). There was a greater range of active and passive knee flexion in the heavy manual occupation group than in the low-impact occupation group (mean active, 3.38° vs 5.33°, respectively [P = .021]; mean passive, 2.76° vs 5.00°, respectively [P = .005]). There was no difference in effusion, anterior knee laxity, limb symmetry index, IKDC score, return-to-sport rate, or graft rupture rate at 12 months.

Conclusion

At 12 months after primary ACLR, male patients engaged in heavy manual occupations had a greater range of knee flexion, with no difference in the effusion rate or anterior knee laxity, compared with those engaged in low-impact occupations.

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.

Revision Anterior Cruciate Ligament, Lateral Collateral Ligament Reconstruction, and Osteochondral Allograft Transplantation for Complex Knee Instability

Anterior cruciate ligament (ACL) injuries rarely occur as an isolated event and often include associated meniscal, subchondral bone, and collateral ligament injuries. Concomitant pathology frequently complicates primary and revision ACL reconstruction and must be addressed to ensure comprehensive diagnosis and treatment. In this Technical Note, we describe our method for treatment of complex knee instability following multiple failed ACL reconstruction using a multiligament reconstruction technique with an osteochondral allograft transplantation to the lateral femoral condyle. This comprehensive repair technique restores the anatomic load bearing forces of the cruciate and collateral ligaments and promotes biological repair through incorporation of cartilage resurfacing to ultimately achieve optimal kinematics of the knee joint.

Exosomes secreted by hypoxia-stimulated bone-marrow mesenchymal stem cells promote grafted tendon-bone tunnel healing in rat anterior cruciate ligament reconstruction model

Background

After anterior cruciate ligament (ACL) reconstruction in clinic, firm and rapid integration of the grafted tendon into the bone tunnel remains a challenge. Exosomes from hypoxia-treated stem cells are beneficial for promoting angiogenesis and then coupling with osteogenesis. Therefore, exosomes from hypoxia-cultured bone-marrow mesenchymal stem cells (Hypo-Exos) may be a cell-free therapy for enhancing graft-bone incorporation after ACL reconstruction.

Methods

Exosomes from normoxia-cultured bone-marrow mesenchymal stem cells (Norm-Exos) or Hypo-Exos were respectively cultured with human umbilical vein endothelial cells (HUVECs) for in-vitro evaluating their functions in HUVECs proliferation, migration, and tube formation. A total of 87 rats with single-bundle ACL reconstructions in the right knee were randomly allocated into 3 different treatments: phosphate-buffered saline (PBS) with the adhesive hydrogel injection as control (Ctrl), Norm-Exos with the adhesive hydrogel injection (Norm-Exos), and Hypo-Exos with the adhesive hydrogel injection (Hypo-Exos). At postoperative weeks 2, 4, or 8, the ACL graft-bone integrations were evaluated.

Results

Hypo-Exos was a better stimulator for in-vitro HUVECs proliferation, migration, and tube formation compared to PBS or Norm-Exos. Hypo-Exos within the adhesive hydrogel could be sustained-released at least 14 days around the peri-graft site. Radiologically, at week 4 or 8, femoral or tibial bone tunnel areas (BTA), as well as bone volume/total volume ratio (BV/TV) of the femoral or tibial peri-graft bone in the Hypo-Exos group, improved significantly better than these parameters of the Ctrl and Norm-Exos groups (P<0.05 for all). Histologically, the grafted tendon-bone interface in the Hypo-Exos group showed significantly higher histologic scores at week 4 or 8 as compared with the other groups (P<0.05 for all). Immunofluorescent staining verified that type H vessels were more abundant in the Hypo-Exos group when compared to the Ctrl or Norm-Exos group at week 2. Biomechanically, the Hypo-Exos group exhibited a significantly heightened failure load compared with the Ctrl and Norm-Exos groups (P<0.05 for all) at 8 weeks. Meanwhile, the stiffness in the Hypo-Exos group was the greatest among the three groups.

Conclusion

Peri-graft Hypo-Exos injection accelerates grafted tendon-bone tunnel integration after ACL reconstruction by improving peri-graft bone microarchitecture.

Arthroscopic Bone Graft Technique for Two-Stage Revision Anterior Cruciate Ligament Reconstruction

Revision anterior cruciate ligament reconstruction is an increasingly common procedure, with 2-stage surgery often required to address large bone defects and malpositioned tunnels. The arthroscopic bone grafting technique described herein uses morselized allograft bone to provide reproducible fill of asymmetrical bone defects without autograft harvest or additional loss of native bone. The second stage of the anterior cruciate ligament reconstruction can typically proceed 6 months following bone grafting.

[Core techniques and adverse events in anterior cruciate ligament reconstruction using a new generation of artificial ligaments: the consensus of Chinese specialists based on a modified Delphi method (Part 2)]

OBJECTIVE

Anterior cruciate ligament (ACL) reconstruction using a new generation of artificial ligaments (NGAL) gained popularity in China owing to its good effectiveness and early functional recovery, but iatrogenic surgical failures and preconceived misconceptions have seriously affected its standardized clinical application. A specialist consensus is now developed to provide guidance and reference for orthopaedic sports medicine doctors when adopting or considering the NGAL for ACL reconstruction.

METHODS

The consensus on the core techniques and adverse events in ACL reconstruction using the NGAL was developed by a modified Delphi method, referring exclusively to the NGAL for ACL reconstruction approved by the National Medical Products Administration (NMPA). Consensus specialists were selected from the members of the Chinese Association of Orthopaedic Surgeons (CAOS) and the Chinese Society of Sports Medicine (CSSM). The drafting team summarized the draft consensus terms based on medical evidence and organized rounds of investigation: two rounds of online questionnaire investigation and the final round of face-to-face meeting. After discussion, revision, and voting, a consensus on the draft consensus term was reached when the agreement rate exceeded 85%. The consensus terms were categorized as "strong" (agreement rate: 95.0%-100%), "moderate" (agreement rate: 90.0%-94.9%), and "basic" (agreement rate: 85.0%-89.9%).

RESULTS

Thirty-one specialists completed the questionnaire investigation. They all practiced in university teaching hospitals (Grade-A tertiary hospitals) from 16 provinces, autonomous regions, and municipalities in China. Among them, 28 were chief physicians and 3 were associate chief physicians; 22 were professors and 7 were associate professors; the average seniority in orthopedic sports medicine was 25.2 years (range, 12-40 years); the average seniority in performing ACL reconstruction procedures was 13.2 years (range, 7-23 years); in terms of the number of ACL reconstruction using the NGAL, 18 completed more than 100 cases, of which 6 had more than 300 cases; in terms of research, 28 had published more than 1 related paper in the past 5 years, of which 13 had published more than 3 related papers. Twenty-six specialists attended the face-to-face meeting and reached a consensus on 9 terms, including 8 strong terms and 1 moderate term.

CONCLUSION

ACL reconstruction using the NGAL must deploy "isometric" or "near-isometric" reconstruction and should preserve the natural ACL remnants as much as possible. Bone tunnel positioning can be performed using intraoperative radiographic measurements or the lateral femoral intercondylar ridge as reference marks. Incorrect positioning of the bone tunnel is the main reason of surgical failure, and there is a lack of consensus on handling interference screws during revision. Bone tunnel enlargement exists after reconstruction but rarely causes related symptoms. Synovitis and infection are uncommon complications. The aging effect of polyethylene terephthalate fiber on the long-term clinical outcomes is unknown and deserves attention.

Descriptive Characteristics and Outcomes of Patients Undergoing Revision Anterior Cruciate Ligament Reconstruction With and Without Tunnel Bone Grafting

BACKGROUND

Lytic or malpositioned tunnels may require bone grafting during revision anterior cruciate ligament reconstruction (rACLR) surgery. Patient characteristics and effects of grafting on outcomes after rACLR are not well described.

PURPOSE

To describe preoperative characteristics, intraoperative findings, and 2-year outcomes for patients with rACLR undergoing bone grafting procedures compared with patients with rACLR without grafting.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 1234 patients who underwent rACLR were prospectively enrolled between 2006 and 2011. Baseline revision and 2-year characteristics, surgical technique, pathology, treatment, and patient-reported outcome instruments (International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS], Western Ontario and McMaster Universities Osteoarthritis Index, and Marx Activity Rating Scale [Marx]) were collected, as well as subsequent surgery information, if applicable. The chi-square and analysis of variance tests were used to compare group characteristics.

RESULTS

A total of 159 patients (13%) underwent tunnel grafting-64 (5%) patients underwent 1-stage and 95 (8%) underwent 2-stage grafting. Grafting was isolated to the femur in 31 (2.5%) patients, the tibia in 40 (3%) patients, and combined in 88 patients (7%). Baseline KOOS Quality of Life (QoL) and Marx activity scores were significantly lower in the 2-stage group compared with the no bone grafting group (P≤ .001). Patients who required 2-stage grafting had more previous ACLRs (P < .001) and were less likely to have received a bone-patellar tendon-bone or a soft tissue autograft at primary ACLR procedure (P≤ .021) compared with the no bone grafting group. For current rACLR, patients undergoing either 1-stage or 2-stage bone grafting were more likely to receive a bone-patellar tendon-bone allograft (P≤ .008) and less likely to receive a soft tissue autograft (P≤ .003) compared with the no bone grafting group. At 2-year follow-up of 1052 (85%) patients, we found inferior outcomes in the 2-stage bone grafting group (IKDC score = 68; KOOS QoL score = 44; KOOS Sport/Recreation score = 65; and Marx activity score = 3) compared with the no bone grafting group (IKDC score = 77; KOOS QoL score = 63; KOOS Sport/Recreation score = 75; and Marx activity score = 7) (P≤ .01). The 1-stage bone graft group did not significantly differ compared with the no bone grafting group.

CONCLUSION

Tunnel bone grafting was performed in 13% of our rACLR cohort, with 8% undergoing 2-stage surgery. Patients treated with 2-stage grafting had inferior baseline and 2-year patient-reported outcomes and activity levels compared with patients not undergoing bone grafting. Patients treated with 1-stage grafting had similar baseline and 2-year patient-reported outcomes and activity levels compared with patients not undergoing bone grafting.

Single-Stage Revision Anterior Cruciate Ligament Reconstruction Using the Stacked Screws Technique

Single-stage revision anterior cruciate ligament (ACL) reconstruction is preferable to 2-stage revision, when possible, as it avoids an additional surgery and recovery period. Malpositioned and/or widened bone tunnels are a common cause of ACL reconstruction failure and are challenging to manage in revision reconstructions. The "stacked screws construct" fills the previous malpositioned tunnels and bone voids with an oversized biocomposite screw as graft material. The revised tunnel can then be drilled in an anatomic "primary" location, even partially overlapping the filler screw. This technique simplifies tunnel management in revision ACL reconstruction.

State of the mineralized tissue comprising the femoral ACL enthesis in young women with an ACL failure

Despite poor graft integration among some patients that undergo an anterior cruciate ligament (ACL) reconstruction, there has been little consideration of the bone quality into which the ACL femoral tunnel is drilled and the graft is placed. Bone mineral density of the knee decreases following ACL injury. However, trabecular and cortical architecture differences between injured and non-injured femoral ACL entheses have not been reported. We hypothesize that injured femoral ACL entheses will show significantly less cortical and trabecular mass compared with non-injured controls. Femoral ACL enthesis explants from 54 female patients (13-25 years) were collected during ACL reconstructive surgery. Control explants (n = 12) were collected from seven donors (18-36 years). Injured (I) femoral explants differed from those of non-injured (NI) controls with significantly less (p ≤ 0.001) cortical volumetric bone mineral density (vBMD) (NI: 736.1-867.6 mg/cm3 ; I: 451.2-891.9 mg/cm3 ), relative bone volume (BV/TV) (NI: 0.674-0.867; I: 0.401-0.792) and porosity (Ct.Po) (NI: 0.133-0.326; I: 0.209-0.600). Injured explants showed significantly less trabecular vBMD (p = 0.013) but not trabecular BV/TV (p = 0.314), thickness (p = 0.412), or separation (p = 0.828). We found significantly less cortical bone within injured femoral entheses compared to NI controls. Lower cortical and trabecular bone mass within patient femoral ACL entheses may help explain poor ACL graft osseointegration outcomes in the young and may be a contributor to the osteolytic phenomenon that often occurs within the graft tunnel following ACL reconstruction.

Flexible Versus Rigid Reaming Systems for Independent Femoral Tunnel Reaming During ACL Reconstruction: Minimum 2-Year Clinical Outcomes

Background:

Radiographic and cadaveric studies have suggested that anatomic anterior cruciate ligament reconstruction (ACLR) femoral tunnel drilling with the use of a flexible reaming system through an anteromedial portal (AM-FR) may result in a different graft and femoral tunnel position compared with using a rigid reamer through an accessory anteromedial portal with hyperflexion (AAM-RR). No prior studies have directly compared clinical outcomes between the use of these 2 techniques for femoral tunnel creation during ACLR.

Purpose:

To compare revision rates at a minimum of 2 years postoperatively for patients who underwent ACLR with AM-FR versus AAM-RR. The secondary objectives were to compare functional testing and patient-reported outcomes between the cohorts.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Included were consecutive patients at a single academic institution between 2013 and 2018 who underwent primary ACLR without additional ligamentous reconstruction. Patients were separated into 2 groups based on the type of anatomic femoral tunnel drilling: AM-FR or AAM-RR. Graft failure, determined by revision ACLR, was assessed with a minimum 2 years of postoperative follow-up. The authors also compared patient-reported outcome scores (International Knee Documentation Committee [IKDC] and Knee injury and Osteoarthritis Outcome Score [KOOS]) and functional performance testing performed at 6 months postoperatively.

Results:

A total of 284 (AAM-RR, 232; AM-FR, 52) patients were included. The mean follow-up time was 3.7 ± 1.5 years, with a minimum 2-year follow-up rate of 90%. There was no significant difference in the rate of revision ACLR between the AAM-RR and AM-FR groups (10.8% vs 9.6%, respectively; P = .806). At 6 months postoperatively, there were no significant between-group differences in peak knee extension strength, peak knee flexion strength, limb symmetry indices, or hop testing, as well as no significant differences in IKDC (AAM-RR, 81.1; AM-FR, 78.9; P = .269) or KOOS (AAM-RR, 89.0; AM-FR, 86.7; P = .104).

Conclusion:

In this limited study, independent femoral tunnel drilling for ACLR using rigid or flexible reaming systems resulted in comparable rates of revision ACLR at a minimum of 2 years postoperatively, with no significant differences in strength assessments or patient-reported outcomes at 6 months postoperatively.

Minimizing the risk of graft failure after anterior cruciate ligament reconstruction in athletes. A narrative review of the current evidence

Anterior cruciate ligament (ACL) tear is one of the most common sport-related injuries and the request for ACL reconstructions is increasing nowadays. Unfortunately, ACL graft failures are reported in up to 34.2% in athletes, representing a traumatic and career-threatening event. It can be convenient to understand the various risk factors for ACL failure, in order to properly inform the patients about the expected outcomes and to minimize the chance of poor results. In literature, a multitude of studies have been performed on the failure risks after ACL reconstruction, but the huge amount of data may generate much confusion.The aim of this review is to resume the data collected from literature on the risk of graft failure after ACL reconstruction in athletes, focusing on the following three key points: individuate the predisposing factors to ACL reconstruction failure, analyze surgical aspects which may have significant impact on outcomes, highlight the current criteria regarding safe return to sport after ACL reconstruction.

Revision anterior cruciate ligament reconstruction and outcomes with different autografts in a population with kneeling customs

OBJECTIVES

This study was designed to evaluate, compare the mid-term functional outcome of revision anterior cruciate ligament reconstruction (ACLR) using different autografts and assess the cause of failure of primary ACLR in an Omani population with kneeling customs.

MATERIALS AND METHODS

Patients with failed primary ACLR who underwent revision ACLR using autografts were included in this retrospective study. The cause of primary ACLR failure and the functional outcome was assessed using the Tegner-Lyholm knee score and compared among bone patella tendon-bone (BPTB), quadriceps tendon (QT), semitendinosus gracilis (STG) autografts used.

RESULTS

One hundred two patients (102 male) were included in the study with a minimum follow-up of 2 years. Thirty-one patients underwent revision with BPTB, 34 with STG and 19 with QT autografts. Majority of the patients (70.23%) achieved good-to-excellent functional outcome based on their Tegner-Lysholm scores. The functional outcome of different autografts was comparable to each other based on Kruskal-Wallis test. The causes of primary ACLR failure were failure due to trauma in 58.33% of patients, technical failure in 22.61% of patients, and nontraumatic failure in 19.04% of patients.

CONCLUSIONS

The functional outcome of revision ACLR in this Middle Eastern Asian Omani population was good-to-excellent, with the patients experiencing no difficulty in performing activities of daily living, including kneeling activities. The outcome of different autografts, BTPB, QT, STSG is similar in high knee flexion patients with no autograft found to be superior. The findings of this study add to the literature on functional outcomes after primary and revision ACLR in a customary kneeling population.

LEVEL OF EVIDENCE III

Failure rate analysis and clinical outcomes of two different femoral tunnel positions using anteromedial portal technique in anterior cruciate ligament reconstruction

AIM

To analyze two different femoral tunnel positions and to evaluate their correlation with clinical, functional outcomes and surgical revision rate in patients who underwent primary arthroscopic anterior cruciate ligament (ACL) reconstruction with anteromedial (AM) portal technique.

METHODS

From January 2015 to October 2018, we recruited 244 patients that underwent primary single-bundle ACL reconstruction, using four strand-semitendinosus graft and AM portal technique for femoral tunnel placement. Patients were divided into two groups based on the different femoral tunnel positions: 117 patients of group A had ACL footprint center femoral tunnel position compared with 127 patients of group B, with femoral tunnel placement close to the AM bundle footprint. Preoperatively and at last follow up, all patients were assessed subjectively by Lysholm, Tegner, and International Knee Documentation Committee (IKDC) scores, while Lachman, Pivot-shift, and KT-1000 tests were performed to evaluate knee joint stability.

RESULTS

Group B patients showed significantly better results in Lysholm, objective, and subjective IKDC scores compared with patients of group A (P < 0.001). A significantly higher surgical failure rate was found in group A than in group B (10.26% vs. 2.3%; P < 0.001). A higher anterior knee laxity was recorded in patients of group A than in patients of group B (1.9 ± 1.1 vs. 1.3 ± 1 mm; P < 0.001); a reduction in mean anterior tibial translation from preoperative to final follow up was found in group B compared with group A (3.5 ± 1.2 vs. 2.7 ± 1.1 mm; P < 0.001). No significant differences in the Tegner scale were found between the two groups.

CONCLUSION

ACL reconstruction performed using the AM portal technique showed better and more satisfactory clinical and functional outcomes associated with a lower failure rate when the femoral tunnel had been placed more eccentrically in the footprint, in the AM bundle center position.

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.

Ideal Combination of Anatomic Tibial and Femoral Tunnel Positions for Single-Bundle ACL Reconstruction

Background:

Anatomic anterior cruciate ligament reconstruction (ACLR) is preferred over nonanatomic ACLR. However, there is no consensus on which point the tunnels should be positioned among the broad anatomic footprints.

Purpose/Hypothesis:

To identify the ideal combination of tibial and femoral tunnel positions according to the femoral and tibial footprints of the anteromedial (AM) and posterolateral (PL) anterior cruciate ligament bundles. It was hypothesized that patients with anteromedially positioned tunnels would have better clinical scores, knee joint stability, and graft signal intensity on follow-up magnetic resonance imaging (MRI) than those with posterolaterally positioned tunnels.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 119 patients who underwent isolated single-bundle ACLR with a hamstring autograft from July 2013 to September 2018 were retrospectively investigated. Included were patients with clinical scores and knee joint stability test results at 2-year follow-up and postoperative 3-dimensional computed tomography and 1-year postoperative MRI findings. The cohort was divided into 4 groups, named according to the bundle positions in the tibial and femoral tunnels: AM-AM (n = 33), AM-PL (n = 26), PL-AM (n = 29), and PL-PL (n = 31).

Results:

There were no statistically significant differences among the 4 groups in preoperative demographic data or postoperative clinical scores (Lysholm, Tegner, and International Knee Documentation Committee subjective scores); knee joint stability (anterior drawer, Lachman, and pivot-shift tests and Telos stress radiographic measurement of the side-to-side difference in anterior tibial translation); graft signal intensity on follow-up MRI; or graft failure.

Conclusion:

No significant differences in clinical scores, knee joint stability, or graft signal intensity on follow-up MRI were identified between the patients with anteromedially and posterolaterally positioned tunnels.

Increase in cartilage degeneration in all knee compartments after failed ACL reconstruction at 4 years of follow-up

Purpose

Degeneration of the cartilage after anterior cruciate ligament reconstruction (ACL-R) is known, and further deterioration can be expected in patients with tunnel malplacement or partial meniscal resection. It was hypothesized that there is a significant increase in cartilage degeneration after failed ACL-R.

Material and methods

Isolated ACL revision surgery was performed in 154 patients at an interval of 46 ± 33 months (5–175 months) between primary and revision surgery. Cartilage status at the medial, lateral femorotibial, and patellofemoral compartments were assessed arthroscopically during primary and revision ACL-R in accordance with the Outerbridge classification. Tunnel placement, roof angle, and tibial slope was measured using anteroposterior and lateral radiographic views.

Results

Cartilage degeneration increased significantly in the medial femorotibial compartment, followed by the lateral and patellofemoral compartments. There was a correlation between both cartilage degeneration in the patellofemoral compartment (PFC) (r_s = 0.28, p = 0.0012) and medial tibial plateau (R_s = 0.24, p = 0.003) in relation to the position of tibial tunnel in the frontal plane. Worsening of the cartilage status in the medial femorotibial compartment, either femoral or tibial, was correlated with the tibial aperture site in the lateral view (R_s = 0.28, p < 0.001). Cartilage degeneration in the lateral compartment of the knee, on both femoral or tibial side, was inversely correlated with the femoral roof angle (R_s = −0.1985, p = 0.02). Meniscal tears, either at the medial or lateral site or at both, were found in 93 patients (60%) during primary ACL-R and increased to 132 patients (86%) during revision ACL-R.

Discussion

Accelerated cartilage degeneration and high prevalence of meniscal lesions are seen in failed ACL-R. Tunnel placement showed significant impact on cartilage degeneration and may partially explain the increased risk of an inferior outcome when revision surgery is required after failed primary ACL-R.

Level of evidence: Level IV—retrospective cohort study.

Current Concepts in Anterior Tibial Closing Wedge Osteotomies for Anterior Cruciate Ligament Deficient Knees

PURPOSE OF REVIEW

Anterior closing wedge osteotomies (ACWO) are utilized to better restore knee stability and in situ forces on anterior cruciate ligament (ACL) grafts during ACL revision reconstruction while reducing the risk of retearing and subsequent revision procedures. However, clinical outcomes following ACWO for patients undergoing ACL reconstruction remains largely limited. The purpose of this review was to provide a concise overview of the current literature on indication, techniques, and outcomes following ACWO in ACL-deficient patients undergoing primary or revision ACL reconstruction while discussing the authors' preferred technique to ACWO during a staged ACL revision reconstruction.

RECENT FINDINGS

Currently available clinical studies and case reports have demonstrated ACWO to improve knee stability and outcomes for patients with an increased posterior tibial slope undergoing primary or revision ACL reconstruction with low complication rates. The ACWO provides an adjunct surgical option to decrease graft failure while improving knee stability and post-surgical outcomes for patients with an increased posterior tibial slope undergoing primary or revision ACL reconstruction. Further investigations are warranted to validate currently reported outcomes following ACWO in higher-level clinical studies with longer-term follow-up.

The Role of Biodegradable Magnesium and Its Alloys in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis Based on Animal Studies

Objective: The actual efficacy of magnesium and its alloy in anterior cruciate ligament reconstruction (ACLR) was systematically evaluated to reduce the risk of translation from animal experiments to the clinic.

Methods: Databases of PubMed, Ovid-Embase, Web of Science, CNKI, Wanfang, VIP, and CBM were searched for literature in July 2021. Screening of search results, data extraction, and literature quality evaluation were undertaken independently by two reviewers.

Results and discussion: Seven articles were selected for the meta-analysis. The results showed that the mechanical properties of the femoral-tendon graft–tibia complex fixed with magnesium and its alloys were comparable to those fixed with titanium and its alloys, and magnesium and its alloys were superior to titanium and its alloys in promoting new bone formation. In addition, the unique biodegradability made magnesium and its alloys an orthopedic implant with significant therapeutic potential. However, whether the degradation rate of magnesium and its alloy can match the rate of bone-tendon integration, and whether the bioconjugation of bone-tendon after degradation can meet the exercise load still needs to be explored in further detail. Simultaneously, it is necessary for future research to improve and standardize experimental design, result measurement, etc., so as to minimize the risk of transforming animal experimental results into clinical practice.

Graft Survivorship After Anterior Cruciate Ligament Reconstruction Based on Tibial Slope

BACKGROUND

Increased tibial slope (TS) is believed to be a risk factor for anterior cruciate ligament (ACL) tears. Increased TS may also promote graft insufficiency after ACL reconstruction.

PURPOSE

To delineate the relationship between TS and single as well as multiple graft insufficiencies after ACL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence 3.

METHODS

We retrospectively identified 519 patients who had sustained ACL graft insufficiency after primary or revision ACL reconstruction (1 graft insufficiency, group A; 2 graft insufficiencies, group B; and ≥3 graft insufficiencies, group C). In addition, a subgroup analysis was conducted in 63 patients who received all surgical interventions by 2 specialized high-volume, single-center ACL surgeons. TS was measured by an observer with >10 years of training using lateral knee radiographs, and intrarater reliability was performed. Multiple logistic and univariate Cox regression was used to assess the contribution of covariates (TS, age, sex, and bilateral ACL injury) on repeated graft insufficiency and graft survival.

RESULTS

The study included 347 patients, 119 female and 228 male, who were 24 ± 9 years of age at their first surgery (group A, n = 260; group B, n = 62; group C, n = 25). Mean TS was 9.8°± 2.7° (range, 3°-18°). TS produced the highest adjusted odds ratio (1.73) of all covariates for repeated graft insufficiency. A significant correlation was found between TS and the number of graft insufficiencies (r = 0.48; P < .0001). TS was significantly lower in group A (9.0°± 2.3°) compared with group B (12.1°± 2.5°; P < .0001) and group C (12.0°± 2.6°; P < .0001). A significant correlation was seen between the TS and age at index ACL tear (r = -0.12; P = .02) as well as time to graft insufficiency (r = -0.12; P = .02). A TS ≥12° had an odds ratio of 11.6 for repeated ACL graft insufficiency.

CONCLUSION

The current results indicate that patients with a markedly increased TS were at risk of early and repeated graft insufficiency after ACL reconstruction. Because the TS is rarely accounted for in primary and revision ACLR, isolated soft tissue procedures only incompletely address recurrent graft insufficiency in this subset of patients.

Two-Stage Revision Anterior Cruciate Ligament Reconstruction with Cannulated Allograft Bone Dowels Soaked in Bone Marrow Aspirate Concentrate

Anterior cruciate ligament reconstruction (ACLR) is one of the most common orthopedic procedures performed each year. The majority of patients undergoing these reconstructions will experience long-term stability and symptomatic relief; however, some will require a revision ACLR procedure. In general, revision ACLRs are more challenging than primary ACLRs due to several diagnostic and technical considerations. A revision ACLR can be performed with either a one-stage or two-stage procedure, which is based on the presence or absence of malpositioned tunnels, bone loss, and tunnel expansion. Recently, the introduction of preshaped allograft bone dowels as a bone grafting option has gained popularity. They provide immediate structural stability and avoid donor site morbidity associated with autografts. The purpose of this article is to outline a bone-grafting tunnel technique with cannulated allograft bone dowels soaked in bone marrow aspirate concentrate (BMAC) used in the first stage of a staged revision ACLR procedure.

Same knee, different goals: patients and surgeons have different priorities related to ACL reconstruction

PURPOSE

The priorities of patients should be shared by those treating them. Patients and surgeons are likely to have different priorities surrounding anterior cruciate ligament reconstruction (ACLR), with implications for shared decision-making and patient education. The optimal surgical approach for ACLR is constantly evolving, and the magnitude of treatment effect necessary for evidence to change surgical practice is unknown. The aim of this study was to determine (1) the priorities of surgeons and patients when making decisions regarding ACLR and (2) the magnitude of reduction in ACLR graft failure risk that orthopaedic surgeons require before changing practice.

METHODS

This study followed a cross-sectional survey design. Three distinct electronic surveys were administered to pre-operative ACLR patients, post-operative ACLR patients, and orthopaedic surgeons. Patients and surgeons were asked about the importance of various outcomes and considerations pertaining to ACLR. Surgeons were asked scenario-based questions regarding changing practice for ACLR based on new research.

RESULTS

Surgeons were more likely to prioritize outcomes related to the surgical knee itself, whereas patients were more likely to prioritize outcomes related to their daily lifestyle and activities. Knee instability and risk of re-injury were unanimous top priorities among all three groups. A mean relative risk reduction in ACLR graft failure of about 50% was required by orthopaedic surgeons to change practice regardless of the type of change, or patient risk profile.

CONCLUSION

There are discrepancies between the priorities of surgeons and patients, and orthopaedic surgeons appear resistant to changing practice for ACLR.

LEVEL OF EVIDENCE

IV.

Revision Anterior Cruciate Ligament Reconstruction: Tibial Tunnel-First Graft-Sizing Technique

Revision anterior cruciate ligament reconstruction (R-ACLR) has become more common as the number of failed primary ACLRs increase. Although increasingly common, R-ACLR has a greater failure rate than a primary reconstruction. Technical errors, particularly in tunnel placement, account for a large proportion of graft failure in R-ACLR as well as re-revision cases. Tunnel placement and trajectory is particularly important in R-ACLR and becomes more challenging with each additional revision attempt. This is in part because any tunnels created for revision may converge with formerly drilled tunnels or face interference hardware creating, complicating proper graft fixation. While there are many approaches to revision ACL surgery, our technique describes a simple, tibial tunnel-first graft-sizing method initially reaming tunnels with very small diameters and sequentially working your way up to more anatomic diameters.

Anterior Cruciate Ligament Revision Reconstruction

Revision anterior cruciate ligament (ACL) reconstruction is used in patients with recurrent instability after primary ACL reconstruction. Identifying the etiology of graft failure is critical to the success of revision reconstruction. The most common etiologies include technical errors, trauma, failure to recognize concomitant injuries, young age, incomplete rehabilitation, and hardware failure. Patients should undergo a complete history and physical examination with a specific focus on previous injury mechanism and surgical procedures. A revision 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. Surgical techniques described in this article include both single-stage and two-stage reconstruction procedures. Rates of return to sport after a revision reconstruction are lower than after primary reconstruction. Future research should be focused on improving both single-stage and two-stage revision techniques, as well as concomitant procedures to address limb malalignment and associated injuries.

The 50 Most Cited Articles in the Indications, Risk Factors, Techniques, and Outcomes of ACL Revision Surgery

The rate of anterior cruciate ligament (ACL) retear remains high and revision ACL reconstruction has worse outcomes compared with primaries. To make advances in this area, a strong understanding of influential research is necessary. One method for systematically evaluating the literature is by citation analysis. This article aims to establish and evaluate "classic" articles. With consideration of these articles, this article also aims to evaluate gaps in the field and determine where future research should be directed. The general approach for data collection and analysis consisted of planning objectives, employing a defined strategy, reviewing search results using a multistep and multiauthor approach with specific screening criteria, and analyzing data. The collective number of citations for all publications within the list was 5,203 with an average of 104 citations per publication. "Biomechanical Measures during Landing and Postural Stability Predict Second Anterior Cruciate Ligament Injury after Anterior Cruciate Ligament Reconstruction and Return to Sport" by Paterno et al contained both the highest number of total citations and the highest number of citations per year, with 403 total citations and 43.9 citations per year. The most recurring level of evidence were level II (n = 18) and level III (n = 17). "Clinical Outcomes" was the most common article type (n = 20) followed by "Risk Factors" (n = 10). The American Journal of Sports Medicine had the highest recorded Cite Factor with over 50% of the articles (n = 27) published. The most productive authors included R.W. Wright (n = 6), S.D. Barber-Westin (n = 5), F.R. Noyes (n = 5), and K.P. Spindler (n = 5). Historically, influential studies have been published in the realms of clinical outcome and risk factor identification. It has been established that revision ACL reconstruction has worse outcomes and more high-level studies are needed. Additionally, prospective studies that apply the knowledge for current known risk factor mitigation are needed to determine if graft tear rates can be lowered.

A Prospective Observational Study on Short-Term Functional Outcome of Arthroscopic Anterior Cruciate Ligament Repair of Proximal Tears Using Knotless Single Suture Anchor Technique

PURPOSE

To assess the clinical outcomes in patients with anterior cruciate ligament (ACL) proximal tears undergoing arthroscopic primary repair with knotless single suture anchor technique.

METHODS

The first twenty-two consecutive patients with proximal ACL tears (Sherman types I and II and high-grade partial tears) treated with arthroscopic primary repair with single suture anchor technique were evaluated until 6 months post-operatively. Patients were evaluated with validated functional outcome measures (IKDC and Lysholm scores) and clinical tests for ACL stability.

RESULTS

At 6-month follow-up, 91% of patients (n = 20) achieved excellent outcome measures for IKDC and Lysholm scores and had complete stability of the ACL to clinical testing. Two patients with poor outcomes at six weeks; one with subjective instability and the other underwent revision surgery represented a failure rate of 9%. The median Lysholm score was 96 (IQ range, 96-100) and median IKDC subjective score was 87.40 (IQ range, 78.20-88.50) at 6-month follow-up. The improvement in Lysholm and IKDC scores over a period of six months post-operatively was statistically significant when compared to preoperative scores (p ≪ 0.0001). Maximum improvement in clinical outcomes is achieved in the first 6 weeks post-surgery with a slower increase thereafter, a time interval which may be considered as a figurative yield point for future work in this field.

CONCLUSION

Arthroscopic ACL primary repair with knotless single suture anchor technique provides excellent short-term clinical outcomes in a carefully selected subset of patients with proximal ACL tears. More powered and longer duration studies are needed to understand longer term outcomes.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Stacked Biocomposite Screws in a Single-Stage Revision Anterior Cruciate Ligament Reconstruction Has Acceptable Fixation Strength in a Porcine Cadaveric Model

BACKGROUND

Stacked screws is a commonly used technique in single-stage revision anterior cruciate ligament (ACL) reconstruction in the setting of bone loss, but there are limited data to support its use.

HYPOTHESIS

Two configurations of a biocomposite stacked screws construct have similar fixation strength and linear stiffness as a primary ACL reconstruction construct in a biomechanical model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 30 porcine legs were divided into 3 groups. Group 1 underwent primary ACL reconstruction with a patellar tendon graft fixed into the femur, with an 8-mm biocomposite interference screw of beta-tricalcium phosphate and poly lactide-co-glycolide. For a revision ACL reconstruction model, groups 2 and 3 had bone tunnels created and subsequently filled with 12-mm biocomposite screws. New bone tunnels were drilled through the filler screw and the surrounding bone, and the patellar bone plug was inserted. Group 2 was fixed with 8-mm biocomposite screws on the side of the graft opposite the filler screw, while group 3 had the interference screw interposed between the graft and the filler screw. The construct was loaded at 1.5 mm/s in line with the tunnel until failure. Load to failure, linear stiffness, and mode of failure were recorded.

RESULTS

The mean pullout strength for groups 1, 2, and 3 was 626 ± 145 N, 653 ± 152 N, and 720 ± 125 N, respectively (P = .328). The mean linear stiffness of the construct in groups 1, 2, and 3 was 71.4 ± 9.9 N/mm, 84.1 ± 11.1 N/mm, and 82.0 ± 10.8 N/mm, respectively. Group 2 was significantly stiffer than group 1 (P = .037).

CONCLUSION

Two configurations of a biocomposite stacked screws construct for a single-stage revision ACL reconstruction in the setting of bone loss show a similar fixation strength and linear stiffness to a primary ACL reconstruction at time zero in a porcine model.

CLINICAL RELEVANCE

In the setting of bone loss from tunnel malpositioning, a single-stage revision ACL reconstruction using a stacked screws construct may provide adequate fixation strength and linear stiffness.

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.

Outside-In Anterior Cruciate Ligament Revision With Lateral Tenodesis and High-Strength Suture Augmentation Is Easy to Perform With the Iliotibial Band

We describe a technique for revision anterior cruciate ligament (ACL) surgery using a 15-cm strip of the iliotibial band as a graft and the gracilis tendon if available. An internal brace is added to augment the graft. The graft is passed through the femur by drilling an outside-in tunnel from the isometric point F9 of Krackow toward the ACL's footprint and is then double fixed at the tibia using an interference screw and a cortical button. This technique makes it possible to perform simultaneous ACL reconstruction and lateral tenodesis with a continuous, rigid, good-diameter graft that is pedicled to the Gerdy tubercle. Good rotational control is achieved, and all the factors that contribute to ligamentization are present.