Morphological Changes of the Femoral Tunnel and Their Correlation With Hamstring Tendon Autograft Maturation up to 2 Years After Anterior Cruciate Ligament Reconstruction Using Femoral Cortical Suspension

Postoperative Magnetic Resonance Imaging after Anterior Cruciate Ligament Reconstruction: An Overview and Practical Step-by-step Guide

Anterior cruciate ligament (ACL) rupture is a frequently encountered injury among athletes, often requiring surgical intervention to restore knee stability. Magnetic resonance imaging (MRI) after ACL reconstruction is common, especially in the evaluation of clinical complications leading to knee instability, decreased range of motion, or pain. This article provides a detailed overview of normal and abnormal postoperative findings including a practical step-by-step guide for MRI assessment. MRI findings must be correlated with surgical technique, time interval from surgery to imaging, and clinical examination.

Hyperbaric oxygen therapy enhances graft healing and mechanical properties after anterior cruciate ligament reconstruction: An experimental study in rabbits

Hyperbaric oxygen therapy (HBOT) has proven successful in wound healing. However, its potential effects on anterior cruciate ligament (ACL) injuries remain uncertain. This study aimed to investigate the impact of HBOT on graft healing following ACL reconstruction in rabbits. Male New Zealand rabbits underwent ACL reconstruction and were randomly divided into two groups: the HBOT group and the ambient air group. The HBOT group received 100% oxygen at 2.5 atmospheres absolute for 2 h daily for 5 consecutive days, starting from the first day after surgery. The ambient air group was maintained in normal room air throughout the entire period. After 12 weeks following the surgery, animals were euthanized, and their knees were harvested for analysis. The HBOT group demonstrated superior graft maturation and integration in comparison to the ambient air group, as evidenced by lower graft signal intensity on magnetic resonance imaging, decreased femoral and tibial tunnel size, and higher bone mineral density values on high-resolution peripheral quantitative computed tomography scans. Additionally, biomechanical testing indicated that the HBOT group had greater load to failure and stiffness values than the ambient air group. In conclusion, the adjuvant use of HBOT improved ACL graft maturation and integration, reduced tunnel widening, and enhanced the biomechanical properties of the graft. These results may provide important insights into the potential clinical application of HBOT as a therapeutic intervention to enhance graft healing after ACL reconstruction, paving the way for further research in this area.

MRI Assessment of Tendon Graft After Lateral Ankle Ligament Reconstruction: Does Ligamentization Exist?

BACKGROUND

No description exists in the literature about the normal evolution of tendon graft after a lateral ankle ligament (LAL) reconstruction.

PURPOSE

To assess the magnetic resonance imaging (MRI) characteristics and the evolution of the tendon graft during different moments in the follow-up after an endoscopic reconstruction of the LAL.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This prospective study included 37 consecutive patients who underwent an endoscopic reconstruction of the LAL with an autograft using the gracilis tendon to treat chronic ankle instability (CAI) resistant to nonoperative treatment (CAI group) and 16 patients without ankle instability (control group). All patients in the CAI group underwent a postoperative assessment at 6, 12, and 24 months using the Karlsson score and MRI examination. Only patients with good and excellent results were included in the study. Graft assessment consisted of qualitative measurements and quantitative evaluations of the reconstructed anterior talofibular ligament (RATFL) and reconstructed calcaneofibular ligament (RCFL), including signal-to-noise quotient (SNQ) and contrast-to-noise quotient (CNQ) measurements in proton density-fat suppressed (PD-FS) and T1-weighted sequences. The analysis of variance test was used to compare the SNQ and the CNQ at different time points for each sequence.

RESULTS

The MRI signal at 6 months was increased compared with that of the control group. Next, a significant signal decrease from 6 to 24 months was noted on PD-FS and T1-weighted images. SNQ measurements on PD-FS weighted images for both the RATFL and the RCFL demonstrated a significantly higher signal (P < .01 and P = .01, respectively) at 6 months compared with that of the control group. Subsequently, the signal decreased from 6 to 24 months. Similarly, CNQ measurements on PD-FS weighted images for both the RATFL and the RCFL demonstrated a significantly higher signal (P < .01 and P < .01, respectively) at 6 months compared with that of the control group. Subsequently, the signal decreased from 6 to 24 months.

CONCLUSION

The present study demonstrated an evolution of the MRI characteristics, suggesting a process of graft maturation toward ligamentization. This is important for clinical practice, as it suggests an evolution in graft properties and supports the possibility of creating a viable ligament.

Editorial Commentary: Quadriceps Tendon Anterior Cruciate Ligament Graft Shows Advantages and Disadvantages

A quadriceps tendon autograft is becoming an increasingly popular graft option for both primary and revision ACL reconstruction. The biomechanical properties of a QT autograft are favorable compared to a bone-patellar tendon-bone (BPTB) or a doubled hamstring (HS) autograft. A QT autograft is associated with less donor site morbidity, such as anterior knee pain and difficulty with kneeling, than a BPTB autograft, and short-term studies have shown comparable clinical results when compared to a BPTB or a HS autograft. However, if harvested with a bone block, a QT autograft carries a higher risk of patellar fracture than a BPTB autograft. Other potential disadvantages include persistent quadriceps weakness, and registry data have shown a higher revision rate compared to a BPTB or HS ACL reconstruction, which is thought to be due to a high learning curve, leading to higher revision rates in low volume centers. Finally, a graft-fixation construct with good time 0 biomechanical characteristics may only be successful in the long term if the graft heals effectively. Time will tell.

Decreased femur tunnel widening after augmented suspensory fixation compared to suspensory fixation for single bundle hamstring ACL reconstruction

Background

Tunnel widening after Anterior cruciate ligament (ACL) reconstruction using a hamstring graft is known to occur at follow-up. Our study aimed to investigate the effect of suspensory fixation augmentation using an interference screw on tunnel widening in single-bundle hamstring ACL reconstruction.

Methods

48 patients who had single bundle ACL reconstruction with femoral fixed loop fixation technique in 15 knees, and, fixed loop with augmented aperture (bio screw) fixation in 33 knees were analyzed. The width of the tunnel was measured using radiographs immediate post-op and at follow-up within 1 year. Computerized Tomogram (CT) measurements of the tunnels and functional scores were also done with overall follow-up for the fixed loop group being 21.33 months (Standard Deviation (SD)11.14) and the Augmentation group 9.12 months (SD 3.83).

Results

Midpoint femur tunnel widening was reduced in the augmentation group, with measurements of 0.74 (SD 1.05) mm Antero Posterior (AP) and 1.01 (SD 1.04) mm in the Lateral view, compared to 1.54 (SD 1.48) mm AP and 1.79 (SD1.47 mm) in the Lateral for the fixed button group. The radiological widening was considerably less in the augmentation group with a p-value of 0.07. AP aperture widening in the augmentation group was 1.25(SD 1.10 mm), and 1.09(SD0.98) mm in the lateral view. The fixed button-only group measured 1.53 (SD1.30) mm in the AP, and 1.65 (SD 1.29) mm in the lateral view, both of which were not statistically significant. The follow-up Lysholm and International Knee Documentation Committee (IKDC) scores were similar for the 2 groups.

Conclusion

Femoral tunnel midpoint and aperture widening were reduced with the fixed loop with aperture (bio screw) augmentation technique for hamstring grafts in single bundle ACL fixation within 1 year with comparable functional scores.

Level of evidence

4.

Extracorporeal Shockwave Therapy Improves Outcome after Primary Anterior Cruciate Ligament Reconstruction with Hamstring Tendons

PURPOSE

The decision regarding the timepoint of a return to sports after anterior cruciate ligament (ACL) reconstruction is complex and depends on many factors, including objectively tested physical and psychological readiness as well as biological healing. The aim of this study was to investigate the influence of repetitive extracorporeal shockwave therapy (ESWT) on return-to-sports duration, clinical results and MRI results after ACL reconstruction with hamstring tendons (HT).

MATERIAL AND METHODS

In this prospective controlled study, all patients with acute ACL ruptures were treated by ACL reconstruction with HT. Patients were randomized into two groups (Group A: ESWT group; Group B: control group). Patients in the ESWT group received focused shockwave therapy 4, 5 and 6 weeks after ACL surgery. Follow-up investigations including IKDC score, Lysholm score, VAS and evaluation regarding return-to-sports timepoints that were conducted 3-, 6-, 9- and 12-months post-operation. An MRI investigation was performed 12-months post-operation and graft maturation (signal intensity ratio (SIR)) as well as femoral and tibial tunnel characteristics (bone marrow oedema, tunnel fluid effusion) were assessed.

RESULTS

In total, 65 patients (27.65 ± 7.07 years; 35 male/30 female) were included in this study. The mean timepoint for "return-to-pivoting-sports" was 27.92 weeks (±2.99) in the ESWT group as well as 42.64 weeks (±5.18) in the control group (p < 0.001). In the ESWT group 31 patients (vs.

CONTROL GROUP

n = 6) attained the "pre-injury activity level", whereas 6 patients (vs.

CONTROL GROUP

n = 22) did not reach this level within 12 months post-operation. The IKDC score, Lysholm score, and VAS showed significant improvement in the ESWT group compared with the control group for all time-points (p < 0.001). The mean SIR in the ESWT group revealed 1.81 (±0.88), whereas the control group showed a mean SIR of 2.68 (±1.04) (p < 0.01).

DISCUSSION

In conclusion, this is the first study investigating the effect of repetitive ESWT on ACL reconstruction with clinical outcome measurements, including the duration of return-to-sports activity and an MRI follow-up examination. Return-to-sports parameters, clinical scores and graft maturation were significantly improved in the ESWT group. This study may support an earlier return-to-sports timepoint by ESWT and is of high clinical relevance as ESWT is a cost-effective treatment option with no relevant side effects.

Radial extracorporeal shockwave therapy reduces pain and promotes proximal tendon healing after rotator cuff repair: Randomized clinical trial

BACKGROUND

Extracorporeal shockwave therapy (ESWT) is widely used to treat soft tissue disorders, but evidence for its application after rotator cuff (RC) repair is lacking.

OBJECTIVES

To investigate the effect of ESWT on short-term functional and structural outcomes after RC repair.

METHODS

Thirty-eight individuals were randomly assigned to the ESWT group (n = 19) or control group (n = 19) 3 months after RC repair. Both groups underwent 5 weeks of advanced rehabilitation and participants in the ESWT group additionally received 2000 pulses of shockwave therapy every week for 5 weeks. The primary outcome was pain measured on a visual analog scale (VAS). Secondary outcomes were range of motion (ROM), Constant score, University of California Los Angeles score (UCLA), American Shoulder and Elbow Surgeons form (ASES), and Fudan University shoulder score (FUSS). Changes in signal/noise quotient (SNQ), muscle atrophy and fatty infiltration were analyzed from MRI. All participants underwent clinical and MRI examinations 3 months (baseline) and 6 months (follow-up) post repair.

RESULTS

A total of 32 participants completed all assessments. Pain and function improved in both groups. At 6 months post repair, pain intensity was lower and ASES scores higher in the ESWT than in the control group (all p-values < 0.01). SNQ near the suture anchor site decreased significantly from baseline to follow-up in the ESWT group (p = 0.008) and was significantly lower than that in the control group (p = 0.036). Muscle atrophy and the fatty infiltration index did not differ between groups.

CONCLUSION

ESWT and exercise more effectively reduced early shoulder pain than rehabilitation alone and accelerated proximal supraspinatus tendon healing at the suture anchor site after RC repair. However, ESWT may not be more effective than advanced rehabilitation in terms of functional outcomes at the short-term follow-up.

Postoperative Tunnel Widening, Elliptical Aperture Shape, and No Preservation of the Remnant Are Related to the Tendon Graft-Bone Tunnel Gap Formation at the Intra-Articular Aperture After Double-Bundle Anterior Cruciate Ligament Reconstruction

Purpose

To examine the bone-tendon healing at the posterolateral (PL) femoral tunnel aperture by second-look arthroscopy after double-bundle anterior cruciate ligament reconstruction (ACLR), and assess the risk factors for impaired healing at the tendon-bone interface.

Methods

A consecutive series of knees undergoing primary double-bundle ACLR using hamstring tendon autografts were enrolled in the study. The exclusion criteria were as follows: previous knee surgeries, concomitant ligamentous and osseous procedures, and a lack of second-look arthroscopy or postoperative computed tomography data for the analysis. Cases in which a gap was identified between the graft and tunnel aperture during the second-look arthroscopic examination were classified as the gap formation (GF) group. A multivariate logistic regression analysis was performed to assess the relationship between the GF and variables that may determine prognosis.

Results

A total of 54 knees that met the inclusion/exclusion criteria were included in the study. Second-look arthroscopy revealed the GF at the PL aperture in 22 of the 54 knees (40%). The time period from surgery to arthroscopy averaged 16 months. In the multivariate logistic regression analysis, the percentage tunnel widening at 1 year on computed tomography (odds ratio, 10.4; 95% confidence interval [CI] 1.56-69.2), ellipticity of the tunnel aperture (odds ratio, 3.57; 95% CI, 0.79-16.11), and no ACL remnant preservation (odds ratio, 5.99; 95% CI, 1.23-29.06) were identified as prognostic factors significantly related to graft-bone tunnel GF.

Conclusions

Second-look arthroscopy revealed GF at the PL graft-bone tunnel interface in 40% of the knees after double-bundle ACLR. Incomplete healing of the interface, as evidenced by a graft-bone gap at the tunnel aperture, was associated with tunnel widening 1-year postsurgery, an elliptical aperture shape, and no preservation of the ACL remnant.

Level of Evidence

Ⅲ, retrospective case-control study.

Morphological Changes in the Tibial Tunnel After ACL Reconstruction With the Outside-In Technique and Adjustable Suspensory Fixation

Background

Anterior cruciate ligament reconstruction (ACLR) using the complete tibial tunnel technique and adjustable-loop cortical suspensory fixation is known to leave a "dead space" that holds the loop device in the tibial tunnel. The consequence of the dead space and its effect on graft healing are still uncertain.

Purpose

To investigate morphological changes in the tibial tunnel and their effect on graft healing, and to identify factors affecting bone healing in the tibial loop tunnel after ACLR with a quadrupled semitendinosus tendon autograft using adjustable suspensory fixation.

Study Design

Case series; Level of evidence, 4.

Methods

Included were 48 patients (34 male, 14 female; mean age, 25.2 ± 5.6 years) who underwent ACLR with a quadrupled semitendinosus tendon autograft using adjustable suspensory fixation. To evaluate tibial tunnel morphology, computed tomography was performed at 1 day and 6 months postoperatively. At 1 year postoperatively, graft healing was assessed on magnetic resonance imaging using the graft signal-to-noise quotient (SNQ). Multivariate regression and correlation analyses were performed to determine any associations between volumetric changes in bone healing and operative variables.

Results

At 6 months after ACLR, a mean of 63.2% of the tibial loop tunnel was filled by bone. Multivariate regression analysis showed that remnant preservation was significantly associated with the loop tunnel filling rate (P < .001). At 1 year after ACLR, the tibial loop tunnel was almost completely closed (98.5%). There were no correlations between loop tunnel volume and graft integration or graft SNQ. A significant but weak correlation was found between graft tunnel volume and intratunnel graft SNQ (P = .10) as well as integration grade in the tibial tunnel (P = .30).

Conclusion

Excellent bone filling in the tibial loop tunnel was seen at 1 year after ACLR. Remnant preservation was significantly associated with the loop tunnel filling rate. A weak correlation was found between graft tunnel volume and intratunnel graft SNQ as well as integration grade in the tibial tunnel.

Radial Extracorporeal Shock Wave Therapy Enhances Graft Maturation at 2-Year Follow-up After ACL Reconstruction: A Randomized Controlled Trial

Background

Graft maturation is an important prognostic factor for hamstring autograft anterior cruciate ligament reconstruction (ACLR). It remains unclear whether extracorporeal shock wave therapy (ESWT) can promote graft healing after ACLR.

Purpose

To evaluate the therapeutic and graft maturation effects of ESWT in hamstring autograft ACLR.

Study Design

Randomized controlled trial; Level of evidence, 1.

Methods

Between May 18, 2019, and September 20, 2019, we randomly assigned 30 patients who met study inclusion criteria to 2 groups. Patients in the control group followed a 5-week advanced rehabilitation training program (30 minutes/session, 5 times/week) starting at 3 months postoperatively. In the ESWT group, together with the 5-week advanced rehabilitation training, radial ESWT was applied once a week for 5 weeks. Functional scores (Lysholm, International Knee Documentation Committee, and Tegner scores), KT-1000 arthrometer knee laxity measurement, and magnetic resonance imaging scans were assessed at 3 months (baseline), 6 months, and 24 months postoperatively. To evaluate graft maturation, we assessed the graft signal-to-noise quotients (SNQs) of the tibial, intra-articular, and femoral sides on magnetic resonance imaging scans. Data were compared between the ESWT and control groups.

Results

In total, 26 patients (13 with ESWT, 13 controls) were assessed. There were no significant between-group differences on any assessment at baseline, and no significant within-group or between-group differences were found in knee laxity at any point. At 24-month follow-up, the ESWT group had significantly higher Lysholm and Tegner scores compared with the controls (P = .012 and .017, respectively). Regarding graft maturation, at 6-month follow-up, the SNQ of the tibial intraosseous graft was significantly lower in the ESWT group versus controls (P = .006), but no differences were detected at the femoral intraosseous graft (P = .321) or the intra-articular graft (P = .314). At 24-month follow-up, the SNQs of the femoral intraosseous graft and intra-articular graft were significantly lower in the ESWT group versus controls (P = .020 and .044, respectively) but no difference was found at the tibial intraosseous graft (P = .579).

Conclusion

Both enhanced graft maturation and improved functional scores at 24-month follow-up were seen in patients who received radial ESWT during rehabilitation after hamstring autograft ACLR.

Registration

ChiCTR1900022853 (Chinese Clinical Trial Registry).

Eccentrically widened bone tunnels after all-inside anterior cruciate ligament reconstruction: a computed tomography and three-dimensional model-based analysis

PURPOSE

To evaluate the extent of tunnel widening after anterior cruciate ligament reconstruction (ACLR) using the all-inside technique and to establish its correlation with patient-reported clinical outcomes and femoral graft bending angle (GBA).

METHODS

Tunnel widening was evaluated using computed tomography (CT)-based three-dimensional (3D) models, and the femoral GBA was directly measured on CT images using the Picture Archiving and Communication System (PACS) software. Clinical follow-up was routine procedure, and patient-reported clinical outcomes mainly included International Knee Documentation Committee (IKDC), Lysholm, and Knee Injury and Osteoarthritis Outcome Scores (KOOS) scores, and subjective knee stability assessment.

RESULTS

Fifty-two patients received standard all-inside ACLR, with a median follow-up of 6 months. Reconstructed anterior cruciate ligaments (ACLs) were scanned during the first 3 days and 6 months after surgery. On both the femoral and tibial sides, bone tunnels were most significantly enlarged at the articular aperture segment; the femoral tunnel was 9.2 ± 1.3 mm postoperatively and was significantly enlarged by 32% to a mean tunnel diameter of 12.1 ± 2.0 mm at 6 months after surgery. Moreover, the extent of tunnel enlargement gradually decreased as the measured levels approached those of the bone cortex. The femoral tunnel center was shifted into the anterior and distal direction, and the tibial tunnel center was shifted into the posterior and lateral direction. Additionally, the mean femoral GBA was 105.9° ± 8.1° at the 6-month follow-up. Tunnel enlargement and GBA were not significantly correlated with patient-reported outcomes.

CONCLUSIONS

Femoral and tibial tunnels were significantly greater and eccentrically shifted at the 6-month follow-up after all-side ACLR. However, the extent of tunnel widening does not markedly affect the short-term clinical outcomes. Meanwhile, the femoral GBA was not significantly correlated with femoral tunnel widening or patient-reported outcomes. Although the tunnel widening following all-inside ACLR was not associated with clinical outcomes, it potentially caused difficulties in revision ACLR.

LEVEL OF EVIDENCE

Level IV.

Tibial tunnel expansion does not correlate with four-strand graft maturation after ACL reconstruction using adjustable cortical suspensory fixation

PURPOSE

Anterior cruciate ligament reconstruction (ACLR) using a short, quadrupled semitendinosus (ST-4) autograft, fixed  with an adjustable suspensory fixation (ASF), has several potential advantages. However, the construct is suspected to generate micromotion, tunnel widening and poor graft maturation. The aim of this study was to evaluate post-operative tibial tunnel expansion, graft maturation and clinical outcomes for this type of ACLR.

METHODS

One-hundred and forty-nine patients were reviewed at a minimum of 2 years following 4-ST ACLR, mean 25.6 ± 3.5 months [24-55], with clinical follow-up and MRI scans. Graft maturity of the intra-articular part of the graft and the tibial tunnel portion was assessed using Signal-to-Noise Quotient (SNQ) and Howell score. Tibial tunnel expansion, bone-graft contact and graft volume in the tibial tunnel were calculated from the MRI scans.

RESULTS

Mean tibial tunnel expansion was 13 ± 16.5% [12-122]. Mean SNQ for graft within the tibial tunnel was 3.8 ± 7.1 [ - 7.7 to 39] and 2.0 ± 3.5 [ - 14 to 17] for the intra-articular portion of the graft. The Howell score for graft within the tibial tunnel was 41% Grade I, 37% Grade 2, 20% Grade 3, 2% grade 4, and for the intra-articular part 61% Grade 1, 26% Grade 2, 13% Grade 3 and 1% Grade 4. The mean tibial tunnel bone-graft contact was 81 ± 23% [0-100] and mean graft volume was 80 ± 22% [0-100]. No correlation was found between tibial tunnel expansion and graft maturity assessed at both locations. Graft maturity was correlated with higher graft-bone contact and graft volume in the tibial tunnel (p < 0.05).

CONCLUSIONS

ST-4 ACLR with ASF had low levels of tunnel enlargement at 2 years. No correlation was found between graft maturation and tibial tunnel expansion. Graft maturity was correlated with graft-bone contact and graft volume in the tibial tunnel.

LEVEL OF EVIDENCE

Level III.

Magnetic Resonance Imaging Assessment of Hamstring Graft Healing and Integration 1 and Minimum 2 Years after ACL Reconstruction

BACKGROUND

An increase has been seen in the number of studies of anterior cruciate ligament reconstruction (ACLR) that use magnetic resonance imaging (MRI) as an outcome measure and proxy for healing and integration of the reconstruction graft. Despite this, the MRI appearance of a steady-state graft and how long it takes to achieve such an appearance have not yet been established.

PURPOSE

To establish whether a hamstring tendon autograft for ACLR changes in appearance on MRI scans between 1 and 2 years and whether this change affects a patient's ability to return to sports.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients with hamstring tendon autograft ACLR underwent MRI and clinical outcome measures at 1 year and at a final follow-up of at least 2 years. MRI graft signal was measured at multiple regions of interest using oblique reconstructions both parallel and perpendicular to the graft, with lower signal indicative of better healing and expressed as the signal intensity ratio (SIR). Changes in tunnel aperture areas were also measured. Clinical outcomes were side-to-side anterior laxity and patient-reported outcome measures (PROMs).

RESULTS

A total of 42 patients were included. At 1 year, the mean SIR for the graft was 2.7 ± 1.2. Graft SIR of the femoral aperture was significantly higher than that of the tibial aperture (3.4 ± 1.3 vs 2.6 ± 1.8, respectively; P = .022). Overall, no significant change was seen on MRI scans after 2 years; a proximal graft SIR of 1.9 provided a sensitivity of 96% to remain unchanged. However, in the 6 patients with the highest proximal graft SIR (>4) at 1 year, a significant reduction in signal was seen at final follow-up (P = .026), alongside an improvement in sporting level. A significant reduction in aperture area was also seen between 1 and 2 years (tibial, -6.3 mm², P < .001; femoral, -13.3 mm², P < .001), which was more marked in the group with proximal graft SIR >4 at 1 year and correlated with a reduction in graft signal. The patients had a high sporting level; the median Tegner activity score was 6 (range, 5-10), and a third of patients scored either 9 or 10. Overall, PROMs and knee laxity were not associated with MRI appearance.

CONCLUSION

In the majority of patients, graft SIR on MRI did not change significantly after 1 year, and a proximal graft SIR <2 was a sensitive indicator for a stable graft signal, implying healing. Monitoring is proposed for patients who have a high signal at 1 year (proximal graft SIR >4), because a significant reduction in signal was seen in the second year, indicative of ongoing healing, alongside an improvement in sporting level. A reduction in tunnel aperture area correlated with a reduction in graft SIR, suggesting this could also be a useful measure of graft integration.

Surgical technique of anterior cruciate ligament ligamentoplasty with pedicular hamstrings via an inside-out approach: BIOFAST hamstring tendons graft

This surgical technique of anterior cruciate ligament (ACL) reconstruction uses a 4-stranded hamstring tendons graft (HG), via an inside-out approach with a femoral cortical button and a tibial screw. It offers preservation of the tibial attachment of the hamstrings and enables double tibial fixation: biological and mechanical. This technique, "BIOFAST HG", does not require any calculation of the length of the tunnels, nor the use of different sized, or adjustable, buttons. If the sliding in the femoral tunnel fails, it is possible to easily convert to a so-called "classic technique". The first 60 cases were reviewed with a conversion rate of 3%. This technique allows the benefits of a pedicled graft over the classic HG technique in a simple way, with minimal conversions to the classic technique.

Randomized controlled trial of all-inside and standard single-bundle anterior cruciate ligament reconstruction with functional, MRI-based graft maturity and patient-reported outcome measures

Background

All-inside anterior cruciate ligament reconstruction (ACLR) is a novel technique that has gained attention due to its minimally invasive and graft-saving properties. However, studies comparing MRI-based graft maturity between all-inside and standard ACLR are lacking.

Purpose

This study focused on the functional, knee laxity, and MRI-based graft maturity characteristics of all-inside and standard single-bundle ACLR.

Study Design

Randomized controlled trial (RCT).

Methods

Fifty-four patients were randomly assigned to an all-inside reconstruction group (n = 27) or standard reconstruction group (n = 27). Using the same rehabilitation strategy. The Tegner, International Knee Documentation Committee, and Lysholm scores were recorded at postoperative months 3, 6, and 12 to assess functional recovery. MRI was conducted to measure the signal/noise quotient (SNQ) of the intra-articular graft to assess the maturity. A higher SNQ indicates lower graft maturity. Knee laxity was assessed using GNRB arthrometer at the postoperative month 12.

Results

The graft SNQ of the all-inside group was significantly higher than that of the standard group at postoperative month 6 (p < 0.05). There was no statistical difference in graft SNQ between the two groups at postoperative months 3 and 12 (p > 0.05). Both groups exhibited the highest SNQ in the middle region of the graft, followed by the proximal region, and the distal region. Functional scores improved significantly for both groups and had no statistical difference (p > 0.05). The knee laxity was higher in the all-inside group (p < 0.05) at postoperative month 12. There was no correlation between the functional scores and graft maturity in both groups (p > 0.05).

Conclusions

All-inside and standard single-bundle ACLR show good functional outcomes; however, knee laxity was relatively higher in the all-inside ACLR group than in the standard ACLR group. Moreover, both techniques exhibited poor maturity in the middle graft region and the best in the distal region. Graft maturity with all-inside ACLR is inferior to that with standard ACLR in the early postoperative stages. There is no correlation between knee function and graft maturity.

Trial registration

Clinical trial registration numbers: ChiCTR1800018543.

Date of registration: 09/23/2018.

Application of Machine Learning Algorithms to Predict Clinically Meaningful Improvement After Arthroscopic Anterior Cruciate Ligament Reconstruction

Background:

Understanding specific risk profiles for each patient and their propensity to experience clinically meaningful improvement after anterior cruciate ligament reconstruction (ACLR) is important for preoperative patient counseling and management of expectations.

Purpose:

To develop machine learning algorithms to predict achievement of the minimal clinically important difference (MCID) on the International Knee Documentation Committee (IKDC) score at a minimum 2-year follow-up after ACLR.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

An ACLR registry of patients from 27 fellowship-trained sports medicine surgeons at a large academic institution was retrospectively analyzed. Thirty-six variables were tested for predictive value. The study population was randomly partitioned into training and independent testing sets using a 70:30 split. Six machine learning algorithms (stochastic gradient boosting, random forest, neural network, support vector machine, adaptive gradient boosting, and elastic-net penalized logistic regression [ENPLR]) were trained using 10-fold cross-validation 3 times and internally validated on the independent set of patients. Algorithm performance was assessed using discrimination, calibration, Brier score, and decision-curve analysis.

Results:

A total of 442 patients, of whom 39 (8.8%) did not achieve the MCID, were included. The 5 most predictive features of achieving the MCID were body mass index ≤27.4, grade 0 medial collateral ligament examination (compared with other grades), intratunnel femoral tunnel fixation (compared with suspensory), no history of previous contralateral knee surgery, and achieving full knee extension preoperatively. The ENPLR algorithm had the best relative performance (C-statistic, 0.82; calibration intercept, 0.10; calibration slope, 1.15; Brier score, 0.068), demonstrating excellent predictive ability in the study’s data set.

Conclusion:

Machine learning, specifically the ENPLR algorithm, demonstrated good performance for predicting a patient’s propensity to achieve the MCID for the IKDC score after ACLR based on preoperative and intraoperative factors. The femoral tunnel fixation method was the only significant intraoperative variable. Range of motion and medial collateral ligament integrity were found to be important physical examination parameters. Increased body mass index and prior contralateral surgery were also significantly predictive of outcome.

Two-year postoperative MRI appearances of anterior cruciate ligament hamstrings autografts are not correlated with functional outcomes, anterior laxity, or patient age

Aims

MRI has been suggested as an objective method of assessing anterior crucate ligament (ACL) graft “ligamentization” after reconstruction. It has been proposed that the MRI appearances could be used as an indicator of graft maturity and used as part of a return-to-sport assessment. The aim of this study was to evaluate the correlation between MRI graft signal and postoperative functional scores, anterior knee laxity, and patient age at operation.

Methods

A consecutive cohort of 149 patients who had undergone semitendinosus autograft ACL reconstruction, using femoral and tibial adjustable loop fixations, were evaluated retrospectively postoperatively at two years. All underwent MRI analysis of the ACL graft, performed using signal-to-noise quotient (SNQ) and the Howell score. Functional outcome scores (Lysholm, Tegner, International Knee Documentation Committee (IKDC) subjective, and IKDC objective) were obtained and all patients underwent instrumented side-to-side anterior laxity differential laxity testing.

Results

Two-year postoperative mean outcome scores were: Tegner 6.5 (2 to 10); Lysholm 89.8 (SD 10.4; 52 to 100); and IKDC subjective 86.8 (SD 11.8; 51 to 100). The objective IKDC score was 86% A (128 patients), 13% B (19 patients), and 1% C (two patients). Mean side-to-side anterior laxity difference (134 N force) was 0.6 mm (SD 1.8; -4.1 to 5.6). Mean graft SNQ was 2.0 (SD 3.5; -14 to 17). Graft Howell scores were I (61%, 91 patients), II (25%, 37 patients), III (13%, 19 patients), and IV (1%, two patients). There was no correlation between either Howell score or SNQ with instrumented anterior or Lysholm, Tegner, and IKDC scores, nor was any correlation found between patient age and ACL graft SNQ or Howell score.

Conclusion

The two-year postoperative MRI appearances of four-strand, semitendinosus ACL autografts (as measured by SNQ and Howell score) do not appear to have a relationship with postoperative functional scores, instrumented anterior laxity, or patient age at surgery. Other tools for analysis of graft maturity should be developed.

Cite this article: Bone Jt Open 2021;2(8):569–575.

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.

Magnetic Resonance Imaging 1 Year After Hamstring Autograft Anterior Cruciate Ligament Reconstruction Can Identify Those at Higher Risk of Graft Failure: An Analysis of 250 Cases

BACKGROUND

There is currently no analysis of 1-year postoperative magnetic resonance imaging (MRI) that reproducibly evaluates the graft of a hamstring autograft anterior cruciate ligament reconstruction (ACLR) and helps to identify who is at a higher risk of graft rupture upon return to pivoting sports.

PURPOSE

To ascertain whether a novel MRI analysis of ACLR at 1 year postoperatively can be used to predict graft rupture, sporting level, and clinical outcome at a 1-year and minimum 2-year follow-up.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Graft healing and integration after hamstring autograft ACLR were evaluated using the MRI signal intensity ratio at multiple areas using oblique reconstructions both parallel and perpendicular to the graft and tunnel apertures. Clinical outcomes were assessment of side-to-side laxity and International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Lysholm, and Tegner activity level scores at 1 year. Repeat outcome measures and detection of graft rupture were evaluated at a minimum of 2 years.

RESULTS

A total of 250 patients (42.4% female) underwent MRI analysis at 1 year, and assessment of 211 patients between 1 year and the final follow-up (range, 24-36 months) detected 9 graft ruptures (4.3%; 5 in female patients). A significant predictor for graft rupture was a high signal parallel to the proximal intra-articular graft and perpendicular to the femoral tunnel aperture (P = .032 and P = .049, respectively), with each proximal graft signal intensity ratio (SIR) increase by 1 corresponding to a 40% increased risk of graft rupture. A cutoff SIR of 4 had a sensitivity and specificity of 66% and 77%, respectively, in the proximal graft and 88% and 60% in the femoral aperture. In all patients, graft signal adjacent to and within the tibial tunnel aperture, and in the mid intra-articular portion, was significantly lower than that for the femoral aperture (P < .001). A significant correlation was seen between the appearance of higher graft signal on MRI and those patients achieving top sporting levels by 1 year.

CONCLUSION

ACLR graft rupture after 1 year is associated with MRI appearances of high graft signal adjacent to and within the femoral tunnel aperture. Patients with aspirations of quickly returning to a high sporting level may benefit from MRI analysis of graft signal. Graft signal was highest at the femoral tunnel aperture, adding further radiographic evidence that the rate-limiting step to graft healing occurs proximally.

Mesenchymal stromal cells and platelet-rich plasma promote tendon allograft healing in ovine anterior cruciate ligament reconstruction

PURPOSE

The effect of bone marrow mesenchymal stromal cells (BMSCs) and platelet-rich plasma (PRP) on tendon allograft maturation in a large animal anterior cruciate ligament (ACL) reconstruction model was reported for the first time. It was hypothesised that compared with non-augmented ACL reconstruction, BMSCs and PRP would enhance graft maturation after 12 weeks and this would be detected using magnetic resonance imaging (MRI).

METHODS

Fifteen sheep underwent unilateral tendon allograft ACL reconstruction using aperture fixation and were randomised into three groups (n = 5). Group 1 received 10 million allogeneic BMSCs in 2 ml fibrin sealant; Group 2 received 12 ml PRP in a plasma clot injected into the graft and bone tunnels; and Group 3 (control) received no adjunctive treatment. At autopsy at 12 weeks, a graft maturation score was determined by the sum for graft integrity, synovial coverage and vascularisation, graft thickness and apparent tension, and synovial sealing at tunnel apertures. MRI analysis (n = 2 animals per group) of the signal-noise quotient (SNQ) and fibrous interzone (FIZ) was used to evaluate intra-articular graft maturation and tendon-bone healing, respectively. Spearman's rank correlation coefficient (r) of SNQ, autopsy graft maturation score and bone tunnel diameter were analysed.

RESULTS

The BMSC group (p = 0.01) and PRP group (p = 0.03) had a significantly higher graft maturation score compared with the control group. The BMSC group scored significantly higher for synovial sealing at tunnel apertures (p = 0.03) compared with the control group. The graft maturation score at autopsy significantly correlated with the SNQ (r = - 0.83, p < 0.01). The tunnel diameter of the femoral tunnel at the aperture (r = 0.883, p = 0.03) and mid-portion (r = 0.941, p = 0.02) positively correlated with the SNQ.

CONCLUSIONS

BMSCs and PRP significantly enhanced graft maturation, which indicates that orthobiologics can accelerate the biologic events in tendon allograft incorporation. Femoral tunnel expansion significantly correlated with inferior maturation of the intra-articular graft. The clinical relevance of this study is that BMSCs and PRP enhance allograft healing in a translational model, and biological modulation of graft healing can be evaluated non-invasively using MRI.

Postoperative Knee and Shoulder

Arthroscopic surgery in the knee most commonly addresses ligament, meniscal, or articular cartilage abnormalities. Similarly, arthroscopic surgery of the shoulder most commonly addresses tendon and labral abnormalities. The expected postoperative MRI findings depend on both the procedure performed and the time since surgery. Identifying complications and failed procedures relies on both clinical and imaging evaluations.