Does Bone Regrow After Notchplasty in ACL Reconstruction? A Prospective Computed Tomography Study With 2-Year Follow-up

Background: During notchplasty in anterior cruciate ligament (ACL) reconstruction, bone is excised from the lateral and roof area of the notch to widen the intercondylar space and avoid notch-graft impingement in extension. There are concerns that bone regrowth of the area will cause narrowing and increase the risk of complications. Purpose: To determine the possibility of late narrowing of the notch after notchplasty using computed tomography (CT) analysis. Study Design: Case series; Level of evidence, 4. Methods: Measurements were performed on CT scans (axial and sagittal planes with knee in extension) in patients who had undergone single-bundle anatomic ACL reconstruction using hamstring graft. Two axial image levels were used: at the anterior outlet and the anterior one-eighth level of the notch. The maximum notch height and width, the notch width at one-third and two-thirds of the preoperative notch midwidth height, the maximum condylar width, and the surface area of the lateral half of the notch were measured preoperatively and at 1 week and 2 years postoperatively. Results: Included were 20 consecutive patients (mean ± standard deviation age, 28 ± 7.3 years; follow-up, 24.2 ± 3.3 months). At the anterior notch outlet, the maximum notch width increased by 1.9 ± 1.7 mm at 1 week postoperatively and narrowed by 0.3 ± 1.1 mm at the final follow-up, while the maximum notch height increased by 1.7 ± 1.9 mm and narrowed by 0.8 ± 1.8 mm, respectively. At one-eighth of the roof length, the maximum notch width increased by 1.1 ± 1.7 mm at 1 week postoperatively and narrowed by 0.1 ± 1.1 mm at the final follow-up, and the maximum notch height increased by 1.2 ± 1.5 mm and narrowed by 0.5 ± 1.5 mm, respectively. All differences were statistically significant when comparing the pre- to the immediate postoperative measurements, and they were nonsignificant when comparing the immediate postoperative to the final follow-up measurements. The same applied for the ratio of maximum notch width to maximum condylar width, indicating no postoperative narrowing of the notch. Conclusion: Notch size-shape after a 2-mm notchplasty did not change significantly in stable knees during the first 2 years after anatomic ACL reconstruction. Surgeons should consider performing this adjuvant technique when there is notch-graft impingement during surgery.

Biomechanical Analysis of Ideal Knee Flexion Angle for ACL Graft Tensioning Utilizing Multiple Femoral and Tibial Tunnel Locations

Anterior cruciate ligament (ACL) graft failure rate has been reported to be greater than 5% at 5 years. Our study evaluated ACL excursion with anatomic and nonanatomic femoral and tibial tunnels to determine optimal flexion angle to tension the ACL to minimize excursion. Ten cadaveric knee specimens were used. The ACL was sectioned and the femoral and tibial attachments were marked. A 1/16-inch drill created a tunnel in the center of the ACL footprint on the tibia and femur and additional tunnels were made 5 mm from this. A suture was passed through each tunnel combination and attached to a string potentiometer. The knee was ranged from full extension to 120 degrees of flexion for 10 cycles while mounted in a custom fixture. The change in length (excursion) of the suture during movement was recorded for each combination of femoral and tibial tunnels. Anatomic reconstruction of the ACL with tunnel placement in the center of the femoral and tibial footprint did not result in an isometric graft, with excursion of the ACL during knee motion of 7.46 mm (standard deviation [SD]: 2.7mm), greatest at 2.84 degrees of flexion (SD: 4.22). The tunnel combination that resulted in the least excursion was a femoral footprint 5 mm anterior to the femoral and 5 mm posterior to the tibial footprint (4. 2mm, SD: 1.37 mm). The tunnel combination that resulted in the most excursion utilized femoral footprint 5 mm proximal to the femoral and 5 mm posterior to the tibial footprint (9.81 mm, SD: 2.68 mm). Anatomic ACL reconstruction results in significant excursion of the ACL throughout motion. If not tensioned properly, the ACL can stretch during range of motion, potentially leading to rerupture. To prevent stretching of the graft, the current biomechanical study recommends tensioning an anatomic ACL reconstruction at its point of maximal excursion, or between 0 and 5 degrees of flexion. Level of Evidence IV

Clinical Outcome Evaluation of Anatomic Anterior Cruciate Ligament Reconstruction With Tunnel Positioning Using Gold Standard Techniques: A Systematic Review and Meta-analysis

Background: There have been conflicting results about the theoretical advantages of anatomic double-bundle anterior cruciate ligament (ACL) reconstruction. Purpose: To evaluate the clinical and functional outcomes comparing anatomic single- versus double-bundle techniques, anatomic versus nonanatomic techniques, and transportal versus outside-in tunnel drilling for ACL reconstruction. Study Design: Systematic review; Level of evidence, 3. Methods: A search was performed in the MEDLINE and EMBASE databases up to August 2018 for clinical trials comparing anatomic ACL reconstruction (with tunnel positioning demonstrated using gold standard radiologic techniques) with another technique, with a minimum functional and biomechanical follow-up of 6 months. A meta-analysis was performed to compare clinical and functional outcomes between anatomic single- versus double-bundle reconstruction and between anatomic versus nonanatomic techniques, using the risk difference or the mean difference. Risk of bias of the included studies was assessed using the Newcastle-Ottawa Scale for cohort and case-control studies and the Cochrane Risk of Bias tool and Jadad Score for randomized controlled trials. Results: Included were 15 studies comprising 1290 patients (follow-up, 12-36 months). No significant differences favoring anatomic double-bundle over anatomic single-bundle reconstruction or outside-in over transportal techniques were found. The meta-analyses showed significant differences in the International Knee Documentation Committee (IKDC) objective score (risk difference, –0.14; 95% confidence interval, –0.27 to –0.01) favoring anatomic over nonanatomic reconstruction. No statistically significant differences were found between anatomic and nonanatomic surgical techniques on other functional scores or clinical examination outcomes, including the IKDC subjective score, Lysholm score, Tegner score, KT-1000 arthrometer test, or pivot-shift test. Conclusion: Double-bundle reconstruction was not superior to the single-bundle technique in clinical and functional outcomes. Anatomic ACL reconstruction shows significantly superior results over nonanatomic ACL reconstruction, reinforcing the anatomic technique as the gold standard choice for clinical practice.

No Difference in Ligamentous Strain or Knee Kinematics Between Rectangular or Cylindrical Femoral Tunnels During Anatomic ACL Reconstruction With a Bone–Patellar Tendon–Bone Graft

Background: As our understanding of anterior cruciate ligament (ACL) anatomy has evolved, surgical techniques to better replicate the native anatomy have been developed. It has been proposed that the introduction of a rectangular socket ACL reconstruction to replace a ribbon-shaped ACL has the potential to improve knee kinematics after ACL reconstruction. Purpose: To compare a rectangular femoral tunnel (RFT) with a cylindrical femoral tunnel (CFT) in terms of replicating native ACL strain and knee kinematics in a time-zero biomechanical anatomic ACL reconstruction model using a bone–patellar tendon–bone (BTB) graft. Study Design: Controlled laboratory study. Methods: In total, 16 fresh-frozen, human cadaveric knees were tested in a 5 degrees of freedom, computed tomography–compatible joint motion simulator. Knees were tested with the ACL intact before randomization to RFT or CFT ACL reconstruction using a BTB graft. An anterior translation load and an internal rotation moment were each applied at 0°, 30°, 60°, and 90° of knee flexion. A simulated pivot shift was performed at 0° and 30° of knee flexion. Ligament strain and knee kinematics were assessed using computed tomography facilitated by insertion of zirconium dioxide beads placed within the substance of the native ACL and BTB grafts. Results: For the ACL-intact state, there were no differences between groups in terms of ACL strain or knee kinematics. After ACL reconstruction, there were no differences in ACL graft strain when comparing the RFT and CFT groups. At 60° of knee flexion with anterior translation load, there was significantly reduced strain in the reconstructed state ([mean ±standard deviation] CFT native, 2.82 ± 3.54 vs CFT reconstructed, 0.95 ± 2.69; RFT native, 2.77 ± 1.71 vs RFT reconstructed, 1.40 ± 1.76) independent of the femoral tunnel type. In terms of knee kinematics, there were no differences when comparing the RFT and CFT groups. Both reconstructive techniques were mostly effective in restoring native knee kinematics and ligament strain patterns as compared with the native ACL. Conclusion: In the time-zero biomechanical environment, similar graft strains and knee kinematics were achieved using RFT and CFT BTB ACL reconstructions. Both techniques appeared to be equally effective in restoring kinematics associated with the native ACL state. Clinical Relevance: These data suggest that in terms of knee kinematics and graft strain, there is no benefit in performing the more technically challenging RFT as compared with a CFT BTB ACL reconstruction.

Three-dimensional realignment and slope reducing osteotomy with anatomic ACL reconstruction in patients with revision anterior cruciate ligament deficiency

Introduction: Current incidence of recurrent anterior cruciate ligament (ACL) instability is 5%, but revision surgery is challenging and requires a thorough analysis of potential risk factor. Moreover, recurrent and chronic ACL instability can result in medial tibio-femoral osteoarthritis (OA). Beside various soft tissue patterns, bony morphologies like a steep posterior tibial slope are associated with an increased anterior tibial translation (ATT) and rotatory instability in the ACL deficient knee. To address the instability and the osteoarthritis a combined procedure is necessary in these patients, however, little is known about the efficacy of such combined procedures. Therefore, the objective of this study was to evaluate the patient reported outcomes and knee stability following combined high tibial osteotomy (HTO) with ACL reconstruction in middle-aged patients with recurrent or chronic cruciate ligament deficiency and mild to moderate medial compartment osteoarthritis (OA). Hypotheses: Methods: Surgical reports and prospectively collected patient reported outcome scores (IKDC, Lysholm, WOMAC, VAS for pain, and Tegner activity score) as well as clinical examination were evaluated retrospectively with a mean follow up of 45.2 ± 14.7 months. Inclusion criteria were 1) high tibial osteotomy with concomitant anatomic ACL reconstruction. Data at final followup were compared to baseline values using the Wilcoxon signed rank test (p < 0.05). Results: 44 patients met the inclusion criteria. 16/44 suffered a graft failure after primary ACL reconstruction, and 8/44 had chronic ACL instability, but had a previous subtotal medial meniscus resection. Mean patient age at surgery was 38.2 ± 10.5 years (range: 18 – 63) with a mean varus alignment of 4.5° ± 1.5°. All patient reported significantly improved outcome scores at final follow-up (VAS 4.3 to 1.5, Lysholm 52.4 to 73.5, IKDC 56.5 to 70.9). However, the change in Tegner score at final follow-up (3.4 to 4.5) was not significant. At final followup 25/44 patients had a removal of the fixation plate. Conclusion: The results of this study indicate, that high tibial osteotomy combined with anatomic single bundle ACL reconstruction is a good treatment option in active middle aged patients suffering from recurrent or chronic ACL deficiency with mild to moderate medial compartment OA. At a median follow-up of 24 months patient reported outcome scores were improved. Especially in patients with multiple ACL reconstruction failures realignment osteotomies should be considered.

Treatment After Anterior Cruciate Ligament Injury: Panther Symposium ACL Treatment Consensus Group

Treatment strategies for anterior cruciate ligament (ACL) injuries continue to evolve. Evidence supporting best-practice guidelines for the management of ACL injury is to a large extent based on studies with low-level evidence. An international consensus group of experts was convened to collaboratively advance toward consensus opinions regarding the best available evidence on operative versus nonoperative treatment for ACL injury. The purpose of this study was to report the consensus statements on operative versus nonoperative treatment of ACL injuries developed at the ACL Consensus Meeting Panther Symposium 2019. There were 66 international experts on the management of ACL injuries, representing 18 countries, who were convened and participated in a process based on the Delphi method of achieving consensus. Proposed consensus statements were drafted by the scientific organizing committee and session chairs for the 3 working groups. Panel participants reviewed preliminary statements before the meeting and provided initial agreement and comments on the statement via online survey. During the meeting, discussion and debate occurred for each statement, after which a final vote was then held. Ultimately, 80% agreement was defined a priori as consensus. A total of 11 of 13 statements on operative versus nonoperative treatment of ACL injury reached consensus during the symposium. Overall, 9 statements achieved unanimous support, 2 reached strong consensus, 1 did not achieve consensus, and 1 was removed because of redundancy in the information provided. In highly active patients engaged in jumping, cutting, and pivoting sports, early anatomic ACL reconstruction is recommended because of the high risk of secondary meniscal and cartilage injuries with delayed surgery, although a period of progressive rehabilitation to resolve impairments and improve neuromuscular function is recommended. For patients who seek to return to straight-plane activities, nonoperative treatment with structured, progressive rehabilitation is an acceptable treatment option. However, with persistent functional instability, or when episodes of giving way occur, anatomic ACL reconstruction is indicated. The consensus statements derived from international leaders in the field will assist clinicians in deciding between operative and nonoperative treatment with patients after an ACL injury.

Treatment after anterior cruciate ligament injury: Panther Symposium ACL Treatment Consensus Group

Treatment strategies for anterior cruciate ligament (ACL) injuries continue to evolve. Evidence supporting best practice guidelines for the management of ACL injury is to a large extent based on studies with low-level evidence. An international consensus group of experts was convened to collaboratively advance toward consensus opinions regarding the best available evidence on operative vs. non-operative treatment for ACL injury. The purpose of this study is to report the consensus statements on operative vs. non-operative treatment of ACL injuries developed at the ACL Consensus Meeting Panther Symposium 2019. Sixty-six international experts on the management of ACL injuries, representing 18 countries, were convened and participated in a process based on the Delphi method of achieving consensus. Proposed consensus statements were drafted by the Scientific Organizing Committee and Session Chairs for the three working groups. Panel participants reviewed preliminary statements prior to the meeting and provided the initial agreement and comments on the statement via an online survey. During the meeting, discussion and debate occurred for each statement, after which a final vote was then held. Eighty percent agreement was defined a-priori as consensus. A total of 11 of 13 statements on operative v. non-operative treatment of ACL injury reached the consensus during the Symposium. Nine statements achieved unanimous support, two reached strong consensus, one did not achieve consensus, and one was removed due to redundancy in the information provided. In highly active patients engaged in jumping, cutting, and pivoting sports, early anatomic ACL reconstruction is recommended due to the high risk of secondary meniscus and cartilage injuries with delayed surgery, although a period of progressive rehabilitation to resolve impairments and improve neuromuscular function is recommended. For patients who seek to return to straight plane activities, non-operative treatment with structured, progressive rehabilitation is an acceptable treatment option. However, with persistent functional instability, or when episodes of giving way occur, anatomic ACL reconstruction is indicated. The consensus statements derived from international leaders in the field will assist clinicians in deciding between operative and non-operative treatments with patients after an ACL injury. Level of evidence V.

Anterior cruciate ligament reconstruction with remnant preservation: current concepts

Anterior cruciate ligament (ACL) tears are a common knee injury, and anatomic ACL reconstruction (ACLR) is now the standard of care to restore knee stability. Nevertheless, re-tear rates exceeding 5% are commonly reported, with an even higher percentage of patients unable to achieve preinjury knee function. As the torn ACL remnant contains elements (eg, cells, blood vessels and mechanoreceptors) essential to ACL function, it has been hypothesised that ACLR with remnant preservation may improve graft remodelling, in turn more quickly and completely restoring ACL structure and function. In this Current Concepts review, we summarise the present understanding of ACLR with remnant preservation, which includes selective bundle reconstruction of partial (one-bundle) ACL tears and single- and double-bundle ACLR with minimal to partial debridement of the torn ACL stump. Reported benefits of remnant preservation include accelerated graft revascularisation and remodelling, improved proprioception, decreased bone tunnel enlargement, individualised anatomic bone tunnel placement, improved objective knee stability and early mechanical support (with selective bundle reconstruction) to healing tissues. However, clinical studies of ACLR with remnant preservation are heterogeneous in the description of remnant characteristics and surgical technique. Presently, there is insufficient evidence to support the superiority of ACLR with remnant preservation over the standard technique. Future studies should better describe the ACL tear pattern, remnant volume, remnant quality and surgical technique. Progress made in understanding and applying remnant preservation may inform, and be reciprocally guided by, ongoing research on ACL repair. The goal of research on ACLR with remnant preservation is not only to achieve anatomic structural restoration of the ACL but also to facilitate biologic healing and regeneration to ensure a more robust and functional graft.

Diagnosis and treatment of rotatory knee instability

Background Rotatory knee instability is an abnormal, complex three-dimensional motion that can involve pathology of the anteromedial, anterolateral, posteromedial, and posterolateral ligaments, bony alignment, and menisci. To understand the abnormal joint kinematics in rotatory knee instability, a review of the anatomical structures and their graded role in maintaining rotational stability, the importance of concomitant pathologies, as well as the different components of the knee rotation motion will be presented. Main Body The most common instability pattern, anterolateral rotatory knee instability in an anterior cruciate ligament (ACL)-deficient patient, will be discussed in detail. Although intra-articular ACL reconstruction is the gold standard treatment for ACL injury in physically active patients, in some cases current techniques may fail to restore native knee rotatory stability. The wide range of diagnostic options for rotatory knee instability including manual testing, different imaging modalities, static and dynamic measurement, and navigation is outlined. As numerous techniques of extra-articular tenodesis procedures have been described, performed in conjunction with ACL reconstruction, to restore anterolateral knee rotatory stability, a few of these techniques will be described in detail, and discuss the literature concerning their outcome. Conclusion In summary, the essence of reducing anterolateral rotatory knee instability begins and ends with a well-done, anatomic ACL reconstruction, which may be performed with consideration of extra-articular tenodesis in a select group of patients.