Effect of Remnant-Preserving Reconstruction of Acute Anterior Cruciate Ligament Injuries in a Rabbit Model: Histological and Biomechanical Analysis

Acute anterior cruciate ligament (ACL) is a key structure that stabilizes knee joints. The objective of this research is to investigate the influence of ligament remnants preserved on the tendon-bone healing following ACL reconstruction and to examine postoperative articular cartilage degeneration in rabbit as a model animal. Sixty New Zealand rabbits are randomly divided into an ACL reconstruction without remnant preservation group (Group A; n = 30) or ACL reconstruction with remnant preservation group (Group B; n = 30). The expression of HIF-1α, VEGF, and micro vessel density (MVD) in the transplanted tendon was detected by immunohistochemical staining at week 6 and 12 after the operation. The signal intensity of the transplanted tendon was observed by MRI scanning, and the width of the bone tunnel was measured by CT scanning at week 6 and 12 after the operation. The graft biomechanics was tested 12 weeks after the operation. The JNK and MMP-13 expression levels were compared to analyze the cartilage degeneration of the knee at week 12 after the operation. The experimental results were analyzed and showed that the remnant-preserving ACL reconstruction is beneficial for bone healing of the tendon in rabbits, but ACL reconstruction with or without ligament remnants preserved will not affect knee articular cartilage degeneration post-surgery.

Remnant preservation with tensioning can improve the clinical outcome after anterior cruciate ligament reconstruction

Background Many studies exist about remnant preservation in anterior cruciate ligament (ACL) reconstruction. However, concern remains for development of a cyclops lesion during remnant preservation. To prevent this, a tensioning method has been suggested. Current study evaluated the clinical and radiologic results of remnant preservation in ACL reconstruction with tensioning compared to classical ACL reconstruction. Methods From January 2016 to June 2017, ACL reconstruction patients who underwent magnetic resonance imaging (MRI) 2 years postoperatively were enrolled. For comparison, all participants were divided in two groups: remnant preservation with tensioning (group R) and controls (group C). Clinically, Hospital for Special Surgery (HSS), International Knee Documentation Committee (IKDC), Lysholm scores, and incidence of symptomatic cyclops lesions were evaluated. Radiologically, signal-to-noise quotient (SNQ) and size of the synovium on MRI as well as anterior instability in Telos stress radiographs were evaluated. Results A total of 64 patients were enrolled (42 in group R and 22 in group C). The IKDC score in group R (70) was better than that in group C (62; p < 0.05). One patient in group R had a cyclops lesion with clinical symptoms and arthroscopic excision was recommended. Radiologically, the SNQ, synovium area, and anterior instability on Telos radiography showed no difference between the two groups. Conclusion Remnant preservation with tensioning is a good option for ACL reconstruction without the development of a cyclops lesion.

Rate of Tibial Tunnel Malposition Is Not Changed by Drilling Entirely Within the Stump of Preserved Remnants During ACL Reconstruction: A Prospective Comparative 3D-CT Study

Background: Remnant preservation during anterior cruciate ligament (ACL) reconstruction (ACLR) is controversial, and it is unclear whether the stump aids or obscures tibial tunnel positioning. Purpose/Hypothesis: The aim of this study was to determine whether the rate of tibial tunnel malposition is influenced by remnant preservation. The hypothesis was that using a remnant-preserving technique to drill entirely within the tibial stump would result in a significant reduction in tibial tunnel malposition as determined by postoperative 3-dimensional computed tomography (3D-CT). Study Design: Cohort study; Level of evidence, 2. Methods: Patients undergoing ACLR between October 2018 and December 2019 underwent surgery with a remnant-preserving technique (RP group) if they had a large stump present (>50% of the native ACL length) or if there was no remnant or if it was <50% of the native length of the ACL, they underwent remnant ablation (RA group) and use of standard landmarks for tunnel positioning. The postoperative tunnel location was reported as a percentage of the overall anteroposterior (AP) and mediolateral (ML) dimensions of the tibia on axial 3D-CT. The tunnel was classified as anatomically placed if the center lay between 30% and 55% of the AP length and between 40% and 51% of the ML length. Results: Overall, 52 patients were included in the study (26 in each group). The mean tunnel positions were 36.8% ± 5.5% AP and 46.7% ± 2.9% ML in the RP group and 35.6% ± 4.8% AP and 47.3% ± 2.3% ML in the RA group. There were no significant differences in the mean AP ( P = .134) and ML ( P = .098) tunnel positions between the groups. Inter- and intraobserver reliability varied between fair to excellent and good to excellent, respectively. There was no significant difference in the rate of malposition between groups (RP group, 7.7%; RA group, 11.5%; P ≥ .999). Conclusion: Drilling entirely within the ACL tibial stump using a remnant-preserving reconstruction technique did not significantly change the rate of tunnel malposition when compared with stump ablation and utilization of standard landmarks.

Functional result of anterior cruciate ligament reconstruction by remnant preservation in a tertiary center in Eastern India

<p><strong>Background:</strong> Anterior cruciate ligament (ACL) reconstruction is one of the most common procedures in orthopaedics. Orthopaedic surgery is vastly evolving to give better functional outcome. Apart from stability, proprioception, ligament healing are important factors for return to sports. The presence of remnant containing mechanoreceptors and free neural endings can help reinnervate the ACL auto graft. Aims and objectives were to evaluate clinical outcomes in patients undergoing ACL reconstruction with remnant preservation.</p><p><strong>Methods</strong>: One hundred and six patients who underwent ACL reconstruction between April 2014 and March 2020. Among these 80 patients underwent remnant preservation. Analysis is done based on international knee documentation committee score (IKDC), modified Cincinnati knee rating system (MCKRS) and Tegner-Lysholm scoring system. Other factors are Lachman test, pivot shift test, return to sports and graft rupture rate.</p><p><strong>Results:</strong> Lachman test became negative in 98% at 12 weeks and in all the patients at 24 months post-operatively. 74 patients (92.5%) among 80 patients develop full range of knee movement after ACL surgery. Post-operative scores are 95, 93, and 92 respectively.</p><p><strong>Conclusions: </strong>Remnant preserving ACL reconstruction having excellent clinical outcome with good knee stability, early return to sports activities and no incidence of graft rupture in our series.</p>