Anterior cruciate ligament reconstruction with remnant preservation: current concepts

Overexpression of CGRP receptor attenuates tendon graft degeneration in anterior cruciate ligament reconstruction

Cell apoptosis or necrosis, extracellular matrix loss, and excessive inflammation may induce tendon graft degeneration. The impairment in the regeneration capability of nerve fibers and blood vessels may be the critical cause. Calcitonin gene-related peptide (CGRP), exhibiting a short half-life, favors cell proliferation, nerve fiber regeneration and angiogenesis. We aimed to investigate the effects of CGRP receptor-mediated signaling on tendon graft integrity and study if the modulation pathways are ascribed to cell proliferation, nerve fiber and blood vessel regeneration. A total of three groups in mice with ACL reconstruction were established: the control group (PBS treatment), the adenovirus vectors expressing CGRP receptor (CALCRL) treated group (Adv-Calcrl treatment), and the adenovirus vectors carrying shRNA targeting Calcrl treated group (Adv-shCalcrl treatment). The histological assessment indicated the Adv-Calcrl treatment was favored while the Adv-shCalcrl significantly impaired tendon graft integrity. TUNEL staining revealed a significant decreased number of apoptotic cells in the Adv-Calcrl group relative to the control group and the adv-shCalcrl group. Compared to the control group and the Adv-shCalcrl group, the Adv-Calcrl group showed significantly enhanced proliferation of nestin positive cells. Of note, the Adv-Calcrl treatment significantly increased EMCN expression at the tendon graft relative to the control and the Adv-shCalcrl groups, which may be ascribed to attenuation of the Hippo signaling pathway. Importantly, the Adv-Calcrl treatment significantly increased sensory nerve fibers and also PIEZO2 levels. Our results demonstrate the activation of CGRP receptor-mediated signaling attenuated tendon graft degeneration, which was ascribed to enhanced proliferation of Nestin positive cells, angiogenesis, and nerve fiber outgrowth.

A Novel Sensor-Based Application for Home-Based Rehabilitation Can Objectively Measure Postoperative Outcomes following Anterior Cruciate Ligament Reconstruction

In order to successfully implement individualized patient rehabilitation and home-based rehabilitation programs, the rehabilitation process should be objectifiable, monitorable and comprehensible. For this purpose, objective measurements are required in addition to subjective measurement tools. Thus, the aim of this prospective, single-center clinical trial is the clinical validation of an objective, digital medical device (DMD) during the rehabilitation after anterior cruciate ligament reconstruction (ACLR) with regards to an internationally accepted measurement tool. Sixty-seven patients planned for primary ACLR (70:30% male-female, aged 25 years [21-32], IKDC-SKF 47 [31-60], Tegner Activity Scale 6 [4-7], Lysholm Score 57 [42-72]) were included and received physical therapy and the DMD after surgery. For clinical validation, combined measures of range of motion (ROM), coordination, strength and agility were assessed using the DMD in addition to patient-reported outcome measures (PROMs) at three and six months after ACLR. Significant correlations were detected for ROM (rs = 0.36-0.46, p < 0.025) and strength/agility via the single-leg vertical jump (rs = 0.43, p = 0.011) and side hop test (rs = 0.37, p = 0.042), as well as for coordination via the Y-Balance test (rs = 0.58, p ≤ 0.0001) regarding the IKDC-SKF at three months. Additionally, DMD test results for coordination, strength and agility (Y-Balance test (rs = 0.50, p = 0.008), side hop test (rs = 0.54, p = 0.004) and single-leg vertical jump (rs = 0.44, p = 0.018)) correlate significantly with the IKDC-SKF at six months. No adverse events related to the use of the sensor-based application were reported. These findings confirm the clinical validity of a DMD to objectively quantify knee joint function for the first time. This will have further implications for clinical and therapeutic decision making, quality control and monitoring of rehabilitation measures as well as scientific research.

Clinical outcomes in stump-preserving versus stump-sacrificing anterior cruciate ligament reconstruction; a randomized controlled study

Background

Anterior Cruciate ligament (ACL) reconstruction (ACLR) aims to restore the anatomy and function of the knee. Although stump preservation during ACLR could be technically challenging, it may improve the revascularization and proprioceptive function of the graft. In this study, we aimed to compare the functional outcome after ACLR with and without stump preservation.

Methods

One hundred and twenty patients with acutely torn ACL and with intact tibial stump were included in this study. Half of them (60 cases) underwent ACLR with stump preservation. The other half (60 cases) had ACLR after total resection of the tibial stump. One hundred and nine out of 120 cases completed their 2 year-follow-up period. All patients were assessed by Tegner activity, Lysholm, and objective International Knee Documentation Committee (IKDC) scores. The side-to-side difference regarding stability was assessed by KT-1000 instrumented Lachman and proprioceptive function was measured by Passive angle reproduction test.

Results

There was no statistically significant difference between both groups regarding Tegner activity, Lysholm, and IKDC scores. Knee stability measured by KT-1000 and complication rate also showed no significant difference. But there was a significant difference in proprioception favoring stump preservation. On the other hand, the operative time was significantly shorter with stump resection. There was no significant difference in the complications rate between both groups and there were no cases with stiffness in either group.

Conclusion

Stump preservation ACLR is a safe technique that yields equivalent functional outcomes to standard ACLR. However; it provides better proprioception. It is more technically challenging, but in experienced hands; it is easily reproducible.

Trial registration

Registration number: NCT05364398. 06/05/2022.

The importance of continuous remnant preservation in anterior cruciate ligament reconstruction

PURPOSE

Selective anteromedial or posterolateral bundle reconstruction is recognized as a treatment modality in partial anterior cruciate ligament (ACL) reconstruction (ACLR) with a biomechanically sufficient ACL remnant. However, there is paucity in literature investigating clinical outcomes of standard ACLR with preservation of residual continuous but biomechanically insufficient ACL tissue. The aim of this study was to investigate the influence of preservation of residual continuous but biomechanical insufficient ACL tissue in standard ACLR on complication and repeat surgery rate, and patient reported and clinical outcome.

METHODS

The retrospective cohort comprised 134 patients (age 23 ± 7 years; Tegner 6 ± 3) with an isolated acute ACL tear. In 67 patients, residual continuous but biomechanically insufficient ACL tissue was present and preserved based on visual inspection, probing of the ACL tissue and Lachman test under arthroscopic view (standard reconstruction with tissue preservation; SRTP). These patients were matched to 67 patients that underwent ACLR where no residual ACL tissue could be preserved (standard reconstruction; SR) based on gender, age and chondral and/or meniscal status. Clinical failure (recurrent instability, pathological ACL graft laxity and/or ACL graft discontinuity), other complication and repeat-surgery rate within index surgery and 1-year and within index surgery and 2-year follow-up, and patient reported and clinical outcomes at 1-year and at 2-year follow-up were compared.

RESULTS

A statistically significant lower clinical failure rate within index surgery and 1-year (SRTP, 3%; SR, 13%; P = 0.028) and within index surgery and 2-year follow-up (SRTP, 3%; SR, 23%; P = 0.001), and revision ACL surgery rate within index surgery and 1-year (SRTP, 2%; ST, 10%; P = 0.029) and within index surgery and 2-year follow-up (SRTP, 2%; SR, 18%; P = 0.001) was found in the SRTP group. No statistically significant differences were found for other investigated outcomes in patients that were without clinical failure.

CONCLUSION

This study shows that in ACLR surgery, preservation of residual continuous but biomechanical insufficient ACL tissue might lead to lower clinical failure rate and ACL revision surgery rate within index surgery and 1-year, and within index surgery and 2-year follow-up compared to standard ACLR where no residual continuous ACL tissue could be preserved.

LEVEL OF EVIDENCE

III.

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.

Arthroscopic anterior cruciate ligament repair with and without suture augmentation: technical note

Anterior cruciate ligament (ACL) tears are routinely treated with an ACL reconstruction. This is based on historical literature reporting high failure rates after ACL repairs in addition to the limited healing potential of the ACL. Recently, improved understanding of pathophysiology of ligamentous healing has led to increasing interest in treating proximal avulsions with excellent tissue quality in the acute setting, as this technique allows for ACL healing. Potential advantages of ACL repair include preservation of native proprioceptive and kinematics of the knee, avoidance of graft harvesting morbidity and the possibility to perform a primary ACL reconstruction in case of failure. As a consequence, several techniques for ACL repair have been proposed that can be performed in isolation or with suture augmentation. The primary aim of this technical note is to describe step-by-step the ACL repair technique with and without suture augmentation. The secondary aim of the current study is to review the indications, patient selection and advantages of the technique.