Quadriceps Tendon Autograft in Pediatric ACL Reconstruction: Graft Dimensions and Prediction of Size on Preoperative MRI

Anterior Cruciate Ligament Reconstruction: Common Intraoperative Mistakes and Techniques for Error Recovery

PURPOSE OF REVIEW

Anterior cruciate ligament (ACL) reconstruction is a commonly performed procedure among general orthopedists, and is a logged procedure required for graduation from accredited orthopaedic residency programs.

RECENT FINDINGS

ACL reconstruction surgery has a number of critical steps, and intraoperative errors can significantly impact the success rate and morbidity of this operation. Technical errors are frequently cited as some of the most common reasons for ACL reconstruction failure. This narrative review provides low-volume surgeons and trainees with an overview of the common errors that can be made during the critical steps of an ACL reconstruction procedure. We suggest technical points for avoiding commonly-encountered errors and provide a description of evidence-supported error recovery techniques to address these errors if they occur intraoperatively. These key steps include femoral tunnel creation, tibial tunnel creation, graft harvest and preparation, and graft fixation within the tunnels. We discuss a number of primary and backup fixation strategies as well as all commonly used autografts (bone-patellar tendon-bone, hamstring, and quadriceps tendon). Additionally, we provide a brief overview on address intra-operative graft contamination citing currently available evidence.

Magnetic Resonance Imaging Can Predict Hamstring or Quadriceps Tendon Autograft Diameter in Pediatric or Adolescent Anterior Cruciate Ligament Reconstruction: A Systematic Review

OBJECTIVE

Insufficient graft diameter is an important factor that contributes to failure rates after anterior cruciate ligament reconstruction (ACLR). Although modalities, such as magnetic resonance imaging (MRI), have been well investigated in the adult population to predict graft diameter preoperatively, it is unclear whether similar strategies can be used in the pediatric population. This review aims to evaluate the utility of MRI in the preoperative estimation of autograft parameters in pediatric or adolescent patients undergoing ACLR.

METHODS

Three databases were searched on January 31, 2024. The authors adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Revised Assessment of Multiple Systematic Reviews guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. Data on demographics, graft characteristics, MRI imaging techniques, and statistical analyses correlating MRI parameters with graft length or diameter were recorded.

RESULTS

Five studies consisting of 450 patients were included in this review (48.4% females). The mean (SD) age at ACLR was 14.7 (6.8) years. Three studies using hamstring tendon (HT) autografts found that combined semitendinosus and gracilis tendon cross-sectional area (ST+GT CSA) were able to predict graft diameter. One study reported an ST+GT CSA cutoff of 31.2 mm 2 to have an 80% and 74% sensitivity and specificity, respectively, in predicting HT autograft diameter above 8 mm. Two studies using quadriceps tendon (QT) autografts found that tendon thickness on sagittal MRI view was able to predict graft diameter. One study reported a QT cutoff of 6.7 mm to have 97.5% and 46.6% sensitivity and specificity, respectively, in predicting the diameter of the QT graft to be above 8 mm. Associations between MRI parameters and graft length were not reported.

CONCLUSION

Although there is limited evidence, ST+GT CSA and QT thickness on sagittal view on MRI can be used to predict intraoperative HT and QT autograft diameter, respectively, in pediatric or adolescent ACLR. Future investigations should investigate correlations between imaging parameters and graft length, especially when using QT autografts in the pediatric population.

LEVEL OF EVIDENCE

Level III.

Quadriceps tendon autograft diameters are routinely above 8 mm, and preoperative size estimation before anterior cruciate ligament reconstruction may not be necessary for this graft type: A systematic review

PURPOSE

To identify values of reported quadriceps tendon (QT) autograft diameter and length in anterior cruciate ligament reconstruction (ACLR), and to identify methods to predict these parameters.

METHODS

A search was conducted across three databases from inception to 30 March 2024. Data on study characteristics, demographics, anthropometric data, imaging techniques, and QT autograft or harvested QT tendon parameters were extracted. Values quantifying the statistical strength of associations between imaging or anthropometric characteristics and graft or tendon parameters as well as for associations between these parameters and postoperative outcomes were recorded.

RESULTS

A total of 3633 patients were included. The weighted mean QT autograft diameter and length were 8.9 (standard deviation [SD]: 0.7, range: 7.8-10.4) mm and 8.1 (SD: 1.3, range: 5.6-9.3) cm, respectively. A total of 93.8% of studies that reported mean QT autograft diameter found a value of 8 mm or greater. The QT groups had similar or significantly greater mean autograft diameter compared to the hamstring tendon (HT) groups in 91.7% of studies that reported significance. Regarding MRI measurements, 71.4% of the correlation coefficients reported showed a moderate positive correlation, 28.6% showed a low positive correlation and 14.3% showed a high positive correlation. Regarding anthropometric characteristics, 33.3% and 16.7%, 16.7% and 14.3% of studies that reported on the relationship between QT autograft diameter and height, weight, body mass index or age, respectively, found a low positive statistically significant correlation. Only statistically nonsignificant associations were reported between QT autograft parameters and post-operative outcomes and complications.

CONCLUSIONS

QT autografts used in ACLR have a mean diameter of 8 mm or greater and are consistently larger than HT autografts. Preoperative MRI measurements are better than anthropometric characteristics at predicting QT autograft parameters; however, preoperative prediction may not be necessary for this graft type. QT autograft parameters were not found to be significantly associated with any post-operative complication or outcome.

LEVEL OF EVIDENCE

Level IV.

The Intra-articular Tendinous Graft Diameter of 10-mm Bone-Patellar Tendon-Bone Autografts in Adolescent Patients: An MRI Analysis of 100 Patients

Background

Bone-patellar tendon-bone (BPTB) autograft size may be one modifiable predictor of anterior cruciate ligament (ACL) reconstruction postoperative success, as smaller graft diameter has been associated with higher rates of rupture requiring revision. However, measuring the true intra-articular tendinous graft diameter of the soft tissue portion of a BPTB graft with standard intraoperative methods is difficult while keeping the graft intact.

Purpose/Hypothesis

The purpose of the study was to use 3-dimensional magnetic resonance imaging (MRI) measurements to determine the cross-sectional area of the soft tissue, tendinous portion of a standard BPTB autograft with 10-mm diameter bone plugs, and, by calculation, the collagen graft size (ie, graft diameter), as would typically be reported in ACL reconstruction studies that consider soft tissue graft size. It was hypothesized that the calculated collagen graft diameter of 10-mm BPTB autografts would be significantly smaller than 10 mm.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A total of 100 patients (10 girls and 10 boys at each age from 13 to 17 years) who underwent a knee MRI at a single academic orthopaedic center without documented extensor mechanism pathology were identified. The central 10-mm width of the patellar tendon that would be harvested for BPTB autograft was measured. The region of interest area tool was then used to measure the cross-sectional area of a 10-mm BPTB graft with subsequent soft tissue autograft diameter calculation.

Results

The mean calculated tendinous graft diameter of a 10 mm-wide BPTB graft was 6.3 ± 0.5 mm and was significantly smaller than a 10-mm reference (P≤ .001). There was no significant association between age and cross-sectional area or graft diameter.

Conclusion

Modern 3-dimensional imaging-based measurement techniques demonstrated that the true intra-articular tendinous soft tissue portion of 10-mm BPTB autografts shows substantial variation and is significantly smaller in diameter than the tunnels typically reamed to accommodate the bone plug portions of these grafts. Moreover, as graft size is a predictor of rupture rate, preoperative MRI-based evaluation may be an important tool when considering BPTB autograft for ACL reconstruction. Future comparative clinical research utilizing graft size as a study variable should consider quantifying and utilizing the diameter of the soft tissue component of BPTB autografts.

Tendon cross-sectional area on magnetic resonance imaging and anthropometric characteristics can be used to predict insufficient four-strand hamstring autograft diameter in anterior cruciate ligament reconstruction: A systematic review

PURPOSE

To evaluate the utility of semitendinosus tendon (ST) and gracilis tendon (GT) cross-sectional area (CSA) on magnetic resonance imaging (MRI) and anthropometric characteristics in preoperative estimation of graft diameter in patients undergoing anterior cruciate ligament reconstruction (ACLR) with four-strand hamstring autografts.

METHODS

Three databases were searched on 29 August 2023. The authors adhered to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and R-AMSTAR (Revised Assessment of Multiple Systematic Review) guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. Data on demographics, anthropometric characteristics, imaging techniques, tendon CSA, correlation coefficients, sensitivities, specificities, regression models and cutoffs for predicting intraoperative graft diameters above 8 mm were recorded.

RESULTS

Forty-six studies comprising 4140 patients were included. Twelve of 19 (63.2%) studies reporting on ST + GT CSA found a moderate to very high correlation with intraoperative graft diameter. Five of 10 (50%) and one of seven (14.3%) studies reporting on ST CSA and GT CSA, respectively, found a moderate to high correlation with intraoperative graft diameter. Cutoffs of ST + GT CSA for predicting graft diameters above 8 mm ranged from 15.8 to 31.2 mm2. Nine of 35 (25.7%) studies that reported on height found a moderate to very high correlation with graft diameter. Seven of 33 (21.2%) studies reporting on weight found a moderate correlation with graft diameter.

CONCLUSION

Of the MRI parameters assessed, ST + GT CSA was the most reliable predictor of graft diameter. However, cutoffs, sensitivities, and specificities for predicting diameters above 8 mm were highly variable. Anthropometric characteristics in general were less predictive of graft diameter than MRI parameters. This information can be used by clinicians to predict patients at risk for ACLR failure due to insufficient graft size.

LEVEL OF EVIDENCE

Level IV.

Quadriceps tendon autograft is promising with lower graft rupture rates and better functional Lysholm scores than hamstring tendon autograft in pediatric ACL reconstruction. A systematic review and meta-analysis

Purpose

Graft rupture is the most prevalent complication following pediatric anterior cruciate ligament reconstruction (ACLR). The hamstring tendon (HT) autograft is frequently employed, while the quadriceps tendon (QT) autograft has garnered increased attention recently. This study aims to perform a systematic review to assess the complication rates and functional outcomes associated with these two widely used autografts in skeletally immature patients - comparing HT versus QT autografts.

Research question

Is QT autograft better than HT autograft for ACLR in skeletally immature cohorts?

Methodology

Three electronic databases (PubMed/Medline, Scopus, and Ovid) were comprehensively searched to identify pertinent articles reporting the outcomes of HT and QT autografts in pediatric ACLR with a minimum 2-year follow-up. Data on the outcome parameters, such as graft rupture rates, contralateral ACL injury rates, functional outcomes, and growth disturbances rates, were extracted. Meta-analysis was performed using OpenMeta Analyst software.

Results

Twelve studies were included for meta-analysis (pooled analysis) with 659 patients (QT: 205; HT: 454). The analysis showed that QT autografts had a significantly lesser graft rupture rate than HT autografts (3.5 % [95 % CI 0.2, 6.8] and 12.4 % [95 % CI 6.1, 18.7] respectively, p < 0.001). The graft rupture rates between QT with bone and without bone block showed no statistically significant difference (4.6 % [95 % CI 0.8, 1.0] and 3.5 % [95 % CI 2.0, 8.9] respectively, p = 0.181). The overall contralateral ACL injury rate was 10.2 %, and the subgroup analysis revealed no statistically significant difference between the QT and HT groups (p = 0.7). Regarding functional outcome scores at the final follow-up, the mean Lysholm score demonstrated a significant increase in the QT group compared to the HT group (p < 0.001). There were no significant differences between the two groups concerning growth disturbances at the final follow-up. Return to sports (RTS) varied between 6 and 13.5 months after surgery.

Conclusion

QT autografts demonstrate encouraging outcomes, showcasing lower graft rupture rates, better functional outcomes, and comparable contralateral ACL injury rates and growth disturbances relative to the commonly used HT autograft in skeletally immature patients undergoing ACLR.

Two-Dimensional Magnetic Resonance Imaging in Preparation for Autograft Anterior Cruciate Ligament Reconstruction Demonstrates Quadriceps Tendon Is Thicker Than Patellar Tendon

Purpose

The purpose of this study was to assess patellar tendon (PT) and quadriceps tendon (QT) thickness on preoperative magnetic resonance imaging (MRI), in both the sagittal and axial planes, at multiple points along each tendon, and to correlate these findings to anthropometric patient data before anterior cruciate ligament (ACL) surgery.

Methods

Patients who underwent PT or QT autograft ACL reconstruction between 2020 and 2022 and who had preoperative MRIs with adequate visualization of the proximal QT and distal PT were retrospectively identified. Patient demographics were recorded (age, height, weight, sex, injury side). Preoperative MRI measurements were performed by 3 independent examiners using standardized protocol. Preoperative MRI measurements were the QT anterior-posterior (AP) thickness at 1, 2, and 4 cm from the proximal patella on axial and sagittal MRI images at the central aspect of the tendon, as well as PT AP thickness at 1, 2, and 4 cm from the distal patella on axial and sagittal MRI images at the central aspect of the tendon.

Results

Forty-one patients (21 females, 20 males) were evaluated, with a mean age of 33.4 years. The quadriceps tendon was significantly thicker than the patellar tendon at all measured locations (P < .0001) with average QT versus PT thickness (in mm) at each level sagittal 1 cm (7.13 vs 4.35), sagittal 2 cm (7.41 vs 4.44), sagittal 4 cm (7.26 vs 4.81), axial 1 cm (7.35 vs 4.50), axial 2 cm (7.63 vs 4.47), axial 4 cm (7.46 vs 4.62), respectively. There were no significant correlations between tendon size and patient body mass index.

Conclusions

The quadriceps tendon is significantly thicker than the patellar tendon at 1, 2, and 4 cm from the patella in both males and females based on preoperative MRI before ACL surgery.

Clinical relevance

Investigating the thickness of the tendons available for autograft harvest before surgery will give us a better understanding of tendon anatomy in the setting of ACL reconstruction.

Surgical techniques in the management of pediatric anterior cruciate ligament tears: Current concepts

Background

Anterior cruciate ligament injury in the child and adolescent patient remains a controversial topic when considering management, especially regarding surgical choices. Treatment variations are seen not just when comparing different countries but also within nations. This arises partly as contemporary treatment is mostly inferred from the adult population who physiologically and in terms of outcomes differ significantly from children. There is an increasing body of evidence for this cohort of patients who have specific challenges and difficulties when determining the optimum treatment.

Methods

Within this article, we will summarize the current evidence for surgical management of anterior cruciate ligament injury for the pediatric patient.

Results and Conclusions

There remain many controversies and gaps inthe treatment of Paediatric Anterior cruciate ligament reconstruction and this high risk cohort continues to cause difficulty in identifying the best mode of surgical management.

Level of evidence

level IV.

Ultrasound Imaging in Predicting the Autograft Size in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis

Anterior cruciate ligament (ACL) reconstruction is widely used to restore knee stability after injury, but the risk of revision surgery increases when the autograft size is inadequate. Ultrasound (US) measurements of preoperative target tendons have been applied to predict the intraoperative autograft size, with various outcomes across different studies. This systematic review and meta-analysis aimed to summarize the evidence and investigate the usefulness of US in predicting autograft size. Electronic databases were searched for relevant studies from inception to 19 January 2022. The primary outcome was the correlation between the preoperative US measurements of donor tendons and intraoperative autograft size. The secondary outcomes encompassed the predictive performance of US for autograft size and the comparison between US and magnetic resonance imaging (MRI) for preoperative tendon measurements. Nine studies, comprising 249 patients, were enrolled. The preoperative US measurements of the donor tendons demonstrated a significant positive correlation with their intraoperative autograft diameter, with a pooled correlation coefficient of 0.443 (95% confidence interval [CI], 0.266−0.591, p < 0.001) for the gracilis and semitendinosus autograft, 0.525 (95% CI, 0.114−0.783, p = 0.015) for the semitendinosus autograft, and 0.475 (95% CI, 0.187−0.687, p = 0.002) for the gracilis autograft. The pooled sensitivity and specificity of US imaging in predicting the autograft diameter were 0.83 (95% CI 0.57−0.95) and 0.70 (95% CI, 0.36−0.91), respectively. Moreover, no significant differences were observed between US and MRI measurements in predicting the sizes of the gracilis and semitendinosus autografts. Preoperative US measurements of the target tendons were moderately correlated with the intraoperative autograft size. US imaging has a discriminative performance similar to that of MRI in predicting the autograft size. A standardized US scanning protocol is needed for future studies to minimize the variations in tendon measurements across different investigators and increase the comparability of US imaging with intraoperative findings.