Effect of Time on MRI Appearance of Graft After ACL Reconstruction: A Comparison of Autologous Hamstring and Quadriceps Tendon Grafts

Knee Anterior Laxity and Graft Maturation After Transphyseal Anterior Cruciate Ligament Reconstruction

BACKGROUND

The failure rate of anterior cruciate ligament (ACL) reconstruction in children and adolescents is a significant concern. Of the multitude of clinical factors that contribute to this risk, delayed maturation and graft laxity are potentially related and modifiable elements. The aim was to investigate knee anterior laxity and graft maturation in children and adolescents. The ligamentization of the graft may be correlated with the residual laxity.

METHODS

A single-center prospective study included skeletally immature patients treated with transphyseal ACL reconstruction using semitendinosus tendon autograft from 2017 to 2019. Participants were evaluated on 4 occasions: preoperatively, then at 6, 12, and 24 months with instrumented laximetry and MRI to analyze graft maturation according to the Signal-to-noise Quotient (SNQ) and Howell classification.

RESULTS

A total of 50 patients (33 boys and 17 girls), with a mean age of 13.2 years (range, 9 to 16) at the time of surgery, were included. Mean side-to-side knee anterior laxity decreased from 2.78 mm preoperatively to 1.59, 1.80, and 1.30 mm (at 6, 12, and 24 mo follow-up, respectively), P <0.05. No statistical difference was noted according to the follow-up or sex. SNQ was unchanged between 6 and 12 months, but a significant difference was demonstrated between 12 months and 24 months ( P =0.008). There was no statistical correlation between laximetry and graft maturation.

CONCLUSIONS

ACL graft ligamentization is delayed in children and adolescents and only occurs between 12 and 24 months postoperatively. Residual laximetry and MRI signal of the graft may become one of the multiple elements upon which to base the decision to return to sport.

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.

Periosteal wrapping of the hamstring tendon autograft improves graft healing and prevents tunnel widening after anterior cruciate ligament anatomic reconstruction

INTRODUCTION

The periosteum is a readily available tissue at the hamstring harvest site that could be utilized to enhance graft healing and prevent tunnel widening without additional cost or morbidity. This study aimed to compare graft healing using magnetic resonance imaging (MRI) and functional clinical outcome scores in a matched cohort of patients who underwent anterior cruciate ligament (ACL) reconstruction with hamstring autografts with or without periosteal augmentation.

MATERIAL AND METHODS

Forty-eight patients who underwent ACL reconstruction (ACLR) were prospectively enrolled: 25 with standard ACLR (ST-ACLR) and 23 with periosteal augmented grafts (PA-ACLR). The same surgical techniques, fixation methods, and postoperative protocol were used in both groups. Signal-to-noise quotient (SNQ), graft healing at the bone-graft interface, graft signal according to the Howell scale, and femoral tunnel widening were evaluated using MRI after 1 year of follow-up. International knee documentation score (IKDC), Lysholm, Tegner activity scale, and visual analog scale for pain were used for functional evaluation at a minimum of 2 years postoperative.

RESULTS

The mean SNQ of the proximal part of the graft was 9.6 ± 9.2 and 2.9 ± 3.3 for the ST-ACLR and PA-ACLR groups, respectively (P = 0.005). The mean femoral tunnel widening was 30.3% ± 18.3 and 2.3% ± 9.9 for the ST-ACLR, PA-ACLR groups, respectively (P < 0.001). Complete graft tunnel healing was observed in 65% and 28% of cases in the PA-ACLR and ST-ACLR groups, respectively. Both groups showed marked improvements in functional scores, with no statistically significant differences.

CONCLUSION

Periosteal wrapping of hamstring tendon autografts is associated with better graft healing and maturation and lower incidence of femoral tunnel widening based on MRI analysis 1 year after ACL reconstruction. However, patient-reported outcomes and measured laxity were similar between the two groups at 2 years follow up.

TRIAL REGISTRATION

Trail registration number: PACTR202308594339018, date of registration: 1/5/2023, retrospectively registered at the Pan African Clinical Trial Registry (pactr.samrc.ac.za) database.

Current trends in graft choice for anterior cruciate ligament reconstruction - part I: anatomy, biomechanics, graft incorporation and fixation

Graft selection in anterior cruciate ligament (ACL) reconstruction is critical, as it remains one of the most easily adjustable factors affecting graft rupture and reoperation rates. Commonly used autografts, including hamstring tendon, quadriceps tendon and bone-patellar-tendon-bone, are reported to be biomechanically equivalent or superior compared to the native ACL. Despite this, such grafts are unable to perfectly replicate the complex anatomical and histological characteristics of the native ACL. While there remains inconclusive evidence as to the superiority of one autograft in terms of graft incorporation and maturity, allografts appear to demonstrate slower incorporation and maturity compared to autografts. Graft fixation also affects graft properties and subsequent outcomes, with each technique having unique advantages and disadvantages that should be carefully considered during graft selection.

Quadriceps tendon autograft for anterior cruciate ligament reconstruction: state of the art

The ideal graft for anterior cruciate ligament reconstruction (ACLR) continues to be debated. Although first described in 1984, use of the quadriceps tendon (QT) autograft has only recently gained popularity. The biomechanical properties of the QT autograft are favourable compared to bone-patellar tendon-bone (BPTB) and doubled hamstring (HS) grafts with a higher load to failure and a modulus of elasticity that more closely approximates the native anterior cruciate ligament (ACL). The QT graft can be harvested with or without a bone plug, as either a full thickness or a partial thickness graft, and even through minimally invasive techniques. The surgeon must be aware of potential harvest risks including patellar fracture or a graft that is of insufficient length. Numerous short-term studies have shown comparable results when compared to BPTB or hamstring HS autografts with similar graft failure rates, patient-reported outcomes. A major advantage of QT ACLR is reduced donor site morbidity compared to BPTB. However, some persistent quadriceps weakness after QT ACLR has also been reported. The current literature shows that use of the QT autograft for ACLR provides equivalent clinical results compared to other autografts with less donor site morbidity. However, future studies with longer follow-up and higher level of evidence are needed to identify specific populations where the QT may have additional advantage.