Cross-sectional area measurement of the semitendinosus tendon for anterior cruciate ligament reconstruction

A novel practical method to predict anterior cruciate ligament hamstring graft size using preoperative MRI

BACKGROUND

Predicting hamstring graft size preoperatively for anterior cruciate ligament (ACL) reconstruction is important for preempting an insufficient diameter in graft size intraoperatively, possibly leading to graft failure. While there are multiple published methods using magnetic resonance imaging (MRI) picture archiving and communication systems (PACS), most are not feasible and practical. Our study aims to (1) practically predict the ACL hamstring graft size in a numerically continuous manner using the preoperative MRI from any native MRI PACS system, (2) determine the degree of correlation between the predicted and actual graft size, and (3) determine the performance of our prediction method if we define an adequate actual graft size as ≥ 8 mm.

METHODS

A retrospective review of 112 patients who underwent primary ACL reconstruction with quadrupled hamstring semitendinosus-gracilis grafts at a tertiary institution was conducted between January 2018 and December 2018. Graft diameter can be predicted in a numerically continuous manner as √[2*(AB + CD)], where A and B are the semitendinosus cross-sectional length and breath, respectively, and C and D are the gracilis cross-sectional length and breath, respectively.

RESULTS

A moderately positive correlation exists between the predicted and actual graft diameter (r = 0.661 and p < .001). Our method yields a high specificity of 92.6% and a moderate sensitivity of 67.2% if we define an adequate actual graft size as ≥ 8 mm. An area under receiver-operating characteristic curve shows good discrimination (AUC = 0.856).

CONCLUSIONS

We present a practical method to predict the ACL hamstring graft size with high specificity using preoperative MRI measurements.

Estimation of Diameter of Quadrupled Hamstring Graft for ACL Reconstruction using Pre-operative MRI Measurement as a Predictive Tool

Introduction

The diameter of the quadrupled Hamstring graft plays a significant role in the incidence of graft failures for ACL reconstruction. The ability to predict the graft size pre-operatively can prepare the surgeon for alternatives in the event of an inadequate graft diameter.

Materials and methods

We retrospectively measured the diameter of the Semitendinosus tendon (ST) on the MRI in all patients who underwent arthroscopic ACL reconstruction using quadrupled Semitendinosus as their graft. We also estimated any correlation between various anthropometric data with pre-operative MRI based Cross Sectional Area (CSA) of the Hamstring tendon and final graft diameter in the South Asian population. The patients were included from Jan 2018 - Dec 2020.

Results

The minimum CSA of ST to predict an eventual graft diameter of 7.5mm was 10.7mm2. The MRI based cross-sectional area measurement showed moderate correlation with the intra-operative graft diameter obtained. (r=0.62, p<0.001). The intra-class correlation coefficient between the radiologist and the surgeon was 0.82, 95% CI (0.57, 0.92) and a p-value <0.001.

Conclusion

Pre-operative MRI can be a useful tool to predict the graft diameter. This coupled with the anthropometric data of the patient can be used as an adjunct to estimate the probable graft diameter. Thus, the surgeon can be better prepared for the surgery and can seek alternate graft options if the graft size is deemed inadequate pre-operatively.

Validity and Reliability of 3-D Ultrasound Imaging to Measure Hamstring Muscle and Tendon Volumes

OBJECTIVE

The validity and reliability of 3-D ultrasound (US) in estimation of muscle and tendon volume was assessed in a very limited number of muscles that can be easily immersed. The objective of the present study was to assess the validity and reliability of muscle volume measurements for all hamstring muscle heads and gracilis (GR), as well as tendon volume for the semitendinosus (ST) and GR using freehand 3-D US.

METHODS

Three-dimensional US acquisitions were performed for 13 participants in two distinct sessions on separate days, in addition to one session dedicated to magnetic resonance imaging (MRI). Volumes of ST, semimembranosus (SM), biceps femoris short (BFsh) and long (BFlh) heads, and GR muscles and from the tendon from semitendinosus (STtd) and gracilis (GRtd) were collected.

RESULTS

The bias and the 95% confidence intervals of 3-D US compared with MRI ranged from -1.9 mL (-0.8%) to 1.2 mL (1.0%) for muscle volume and from 0.01 mL (0.2%) to -0.03 mL (-2.6%) for tendon volume. For muscle volume assessed using 3-D US, intraclass correlation coefficients (ICCs) ranged from 0.98 (GR) to 1.00, and coefficients of variation (CV) from 1.1% (SM) to 3.4% (BFsh). For tendon volume, ICCs were 0.99, and CVs between 3.2% (STtd) and 3.4% (GRtd).

CONCLUSION

Three-dimensional US can provide a valid and reliable inter-day measurement of hamstrings and GR for both muscle and tendon volumes. In the future, this technique could be used as an outcome for strengthening interventions and potentially in clinical environments.

Anthropometric Measurements of Hamstring Tendon Graft and Its Predictors in Ligament Reconstruction Surgeries of Knee: An Observational Study

Introduction Hamstring graft use has been in the forefront of ligament reconstruction around the knee. With the increasing number of surgeries, the complications are equally on the rise. One of the detrimental factors for predicting the outcome is the diameter and length of the graft. We did an observational study to find out the relationship of patient factors with the morphometry of the graft.

Materials and Methods Total 484 patients were included in the study. Preoperatively, the age, sex, height, weight, and activity levels of the patients were noted. They were categorized into two major groups: physically active and inactive. The intraoperative measurements of the grafts were recorded. Analysis of variance for comparing the means of multiple groups was used for statistical analysis.

Results Among the total 484 patients, 407 were male and 77 were female. The semitendinosus graft diameter did not show any statistical significance to the age and weight of the patient. The mean graft diameter was highest in the 45 to 49-year age group. The average graft diameter in physically active group was 3.704 mm, and 3.503 mm in the inactive group. This and the height of the patient proved to have statistically significant relation with graft diameter.

Conclusion Physical activity along with the height of the patient must be taken into due consideration before embarking upon ligament reconstruction with hamstring graft in mind, as these two are found to determine the diameter and length of the hamstring graft.

Effect of Cross-sectional Area of the Hamstring Tendon Autograft on Failure Rate or Clinical Outcomes After Double-Bundle ACL Reconstruction: Tendon Autograft

Background

In previous studies examining the relationship between graft size and failure rate after anterior cruciate ligament reconstruction (ACLR), graft size was determined as diameter of the bone tunnel, and graft failure was defined as revision surgery. Consequently, the correlation between graft size and postoperative recurrent instability could not be assessed.

Purpose

(1) To intraoperatively measure the cross-sectional area (CSA) of the hamstring tendon (HT) autograft and compare the CSA of the autograft with the bone tunnel and (2) to assess the effect of the graft CSA on postoperative graft failure among patients who underwent double-bundle ACLR.

Study Design

Case-control study; Level of evidence, 3.

Methods

The study included 129 patients who underwent double-bundle ACLR using an HT autograft (mean ± SD age, 16.7 ± 1.7 years; all with a Tegner activity level ≥6). All patients had a minimum follow-up of 2 years. During surgery, the graft CSA was measured using an area micrometer, combining the anteromedial (AM) and posterolateral (PL) grafts. The total area of the bone tunnel was defined as the combined CSAs of the AM and PL tunnels as calculated by the diameter of the drill. The relationship between the CSAs of the combined HT graft and the bone tunnel was statistically compared, as was the relationship between graft CSAs and graft failure, defined as reinjury, recurrent instability manifested as quantitative laxity measurement, or revision ACLR.

Results

The CSAs of the midsubstance of the combined AM and PL graft significantly correlated with those of the bone tunnels (femoral side, R ² = 0.334, P < .0001; tibial side, R ² = 0.421, P < .0001). As for the relationship between the graft CSA and ACLR failure, there was no significant difference in the graft CSAs between the groups with and without graft failure in any of the failure criteria (P = .188).

Conclusion

The graft CSA was not a predictor of early failure after double-bundle ACLR using an HT autograft in this patient population.

Combined Assessments of Patellar Tendon and Hamstring Tendon Parameters on Preoperative Magnetic Resonance Imaging Can Improve Predictability of Hamstring Tendon Autograft Diameter in the Setting of Anterior Cruciate Ligament Reconstruction

Purpose

To evaluate whether preoperative magnetic resonance imaging (MRI) measurements of multiple tendon autograft sources could be used to improve estimates of intraoperative hamstring tendon autograft (HTA) diameter.

Methods

Patients who underwent anterior cruciate ligament reconstruction with HTA at our institution were identified through electronic health records. Preoperative MRI tendon measurements of the patellar tendon (PT) length, PT width, PT thickness, quadriceps tendon thickness, semitendinosus tendon (ST) cross-sectional area (CSA), and gracilis tendon (GT) CSA were conducted by 2 independent evaluators using digital imaging measurement tools.

Results

A total of 53 patients met the inclusion criteria, with a mean HTA diameter of 7.98 ± 0.7 mm. Height greater than 1.63 m, weight greater than 63.4 kg, PT length greater than 4.2 cm, PT thickness greater than 0.33 cm, ST CSA greater than 10.8 mm², and GT CSA greater than 6.3 mm² were associated with an HTA of 8 mm or greater (P < .005). Female sex was associated with an HTA of less than 8 mm (P < .05). PT length, PT thickness, and GT CSA were the strongest predictors of an HTA of 8 mm or greater and were combined into an additive logistic regression model: Score = -23.24 + (1.68 × PT length) + (20.104 × PT thickness) + (1.48 × GT CSA). If the score was greater than 0.237, the HTA graft diameter was predicted to be 8 mm or greater with 83% specificity, 91% sensitivity, and 87% accuracy.

Conclusions

By combining PT length and PT thickness measurements with GT CSA measurements in a logit function model, we were able to show improved overall specificity, sensitivity, and accuracy of estimated HTA diameters in our data set when compared with assessments of anthropometric, ST CSA, GT CSA, or combined ST-GT CSA measurements in isolation.

Clinical Relevance

Preoperative MRI measurements may be used to screen whether a patient is likely to have an 8-mm graft in the setting of anterior cruciate ligament reconstruction with HTA and thus may help guide graft choice.

Comparison of clinical outcomes of using the nonirradiated and irradiated allograft for anterior cruciate ligament (ACL) reconstruction: A systematic review update and meta-analysis

BACKGROUND

This study was a systematic review comparing the clinical outcomes of using the nonirradiated and irradiated allograft for anterior cruciate ligament (ACL) reconstruction.

METHODS

A comprehensive literature search was conducted using multiple databases, including Medline, Embase, and Cochrane. All databases were searched from the earliest records through August 2019 using the following Boolean operators: irradiated AND nonirradiated AND ACL AND allograft. All prospective and retrospective controlled trials were retrieved that directly compared physical examination and knee function scores and patient-rated outcomes between the nonirradiated and irradiated allograft for ACL reconstruction.

RESULTS

Three prospective and 2 retrospective articles were identified by the search, and the findings suggested that the nonirradiated allografts were superior to the irradiated allografts based on improved knee joint functional scores and decreased failure rate, even though there was no significantly difference with respect to overall IKDC, range of motion, vertical jump test, and one-leg hop test.

CONCLUSIONS

Irradiated allograft should be limited to be used in ACL surgery and further research into new alternative sterilization techniques are needed to avoiding the disease transmission without interference with the biomechanical properties of the grafts.

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.

Chronological changes in cross-sectional area of the bone-patellar tendon-bone autograft after anatomic rectangular tunnel ACL reconstruction

PURPOSE

The purpose of this study was to evaluate the change in cross-sectional area (CSA) of bone-patellar tendon-bone (BTB) autografts up to 5 years after the anatomic rectangular tunnel (ART) anterior cruciate ligament reconstruction (ACLR). The changing pattern in CSA might be a potential indicator of the graft remodeling process.

METHODS

Ninety-six (62 males, 34 females, mean age 27.0 years) patients were enrolled in this study with a total of 220 MRI scans after ART BTB ACLR to evaluate the CSA of the ACL autografts. The patients with first time unilateral ACLR that consented to undergo MRI evaluations at postoperative periods were included in this study. Intraoperatively, the CSA of the graft was measured directly using a custom-made area micrometer at the midpoint of the graft. Postoperatively, using an oblique axial slice MRI that was perpendicular to the long axis of the graft, the CSA of the graft was measured with digital radiology viewing program "SYNAPSE" at the midpoint of the graft. The postoperative MRI scans were classified into seven groups according to the period from ACLR to MRI evaluation: Group 0-2 months (m.), Group 3-6 m., Group 7-12 m., Group 1-2 years (y.), Group 2-3 y., Group 3-4 y., and Group 4 y.-. The percent increase of the CSA was calculated by dividing the postoperative CSA by the intraoperative CSA.

RESULTS

The postoperative CSA was significantly larger than the intraoperative CSA in each group, with the exception of Group 0-2 m. The mean percent increase of the CSA in Group 0-2 m., 3-6 m., 7-12 m., 1-2 y., 2-3 y., 3-4 y., 4 y.- was 101.8 ± 18.2, 188.9 ± 27.4, 190.9 ± 43.7, 183.3 ± 28.9, 175.2 ± 27.9, 163.9 ± 19.8, 164.5 ± 25.4% respectively. The percent increase in Group 3-6 m., 7-12 m., 1-2 y., 2-3 y., 3-4 y., and 4 y.- was significantly greater than that in Group 0-2 m.

CONCLUSIONS

The CSA of the BTB autografts after the ART BTB ACLR increases rapidly by 3-6 months after ACLR, reached a maximum value of 190% at around 1 year, decreases gradually after that, and reaches a plateau at around 3 years. The current study might help clinicians to estimate an individual BTB autograft's remodeling stages when considering returning patients to sports.

LEVEL OF EVIDENCE

IV.

Suture Slippage During Anterior Cruciate Ligament Graft Passage Is Significantly Lower Using a Krackow Suture

Purpose

To compare the suture slippage on a hamstring tendon graft prepared with a modified finger-trap device (SPEEDTRAP) with one prepared with Krackow stitch during graft passage through the tibial tunnel in ACL reconstruction.

Methods

Thirty-eight patients underwent anatomic triple-bundle anterior cruciate ligament reconstruction with 2 femoral and 3 tibial tunnels. After semitendinosus tendon was cut in half to make 2 grafts, the free ends of the proximal membranous portion (posterolateral [PL] graft) were prepared together with 2 sutures: (1) one SPEEDTRAP and one Krackow stitch for 20 cases (group A) and (2) double Krackow stitches on both sides for 18 cases (group B). Then, the PL graft was dye-marked at the proximal suture of SPEEDTRAP in group A and Krackow suture in group B and was inserted into the joint via tibial tunnel ahead of the loop side. The distance between the mark on the graft and the proximal suture of SPEEDTRAP or Krackow stitch was measured under arthroscopy after graft fixation at femur. Slippage was defined as 1 mm and more of distance between the mark and the proximal suture.

Results

Slippage was observed in 16 cases for SPEEDTRAP and in 2 for Krackow suture in group A, whereas one case showed slippage in group B. The slippage distance was 4.0 ± 2.9 mm for SPEEDTRAP and 0.2 ± 0.5 mm for Krackow stitch in group A (P < .001), whereas it was 0.1 ± 0.2 mm for double Krackow stitch in group B, showing a significant difference from SPEEDTRAP suture (P < .001).

Conclusions

At the time of PL graft passage through the tibial tunnel in anterior cruciate ligament reconstruction, there was significantly less slippage observed with the Krackow stitch compared with the SPEEDTRAP stitch.

Level of Evidence

Level IV, therapeutic case series.

Anatomical Triple Bundle Anterior Cruciate Ligament Reconstructions With Hamstring Tendon Autografts: Tunnel Locations and 2-Year Clinical Outcomes

PURPOSE

To anatomically clarify the location of the tunnel apertures created using the bony landmark strategy and to elucidate clinical outcomes after anatomic triple-bundle (ATB) anterior cruciate ligament (ACL) reconstruction.

METHODS

Thirty-two patients with unilateral ACL injury who had consented to undergo computed tomography (CT) at 3 weeks, as well as 2-year follow-up evaluation, were enrolled. At the time of surgery, remnant tissues were thoroughly cleared to create 2 femoral and 3 tibial tunnels inside the ACL attachment areas bordered by the bony landmarks. Two double-looped semitendinosus tendon autografts were prepared and fixed on the femur with two EndoButton-CLs and secured to the tibia with pullout sutures and plates with 10-20N of tension. The location of the tunnel aperture areas was assessed using 3-dimensional CT images, and 2-year postoperative clinical outcomes were evaluated.

RESULTS

The CT evaluation showed 100% of the femoral tunnel aperture area and at least 79% of the tibial tunnel aperture area were located inside the anatomic attachment areas. Thirty patients were available for clinical evaluation. The International Knee Documentation Committee subjective assessment showed all of the patients were classified as "normal" or "nearly normal." Lachman and pivot-shift tests were negative in 100% and 93%, respectively. The mean side-to-side difference of anterior laxity at the maximum manual force with a KT-1000 Knee Arthrometer was 0.7 ± 0.7 mm, ranging from 0 to 2 mm.

CONCLUSION

In ATB ACL reconstructions with hamstring tendon grafts, the tunnels can be created in proper locations using the arthroscopically-identifiable bony landmarks. Moreover, ATB ACL reconstruction with hamstring tendon grafts via the proper tunnels result in consistently satisfactory clinical outcomes.

LEVEL OF EVIDENCE

Level IV, case series.

Clinical outcome of a new remnant augmentation technique with anatomical double-bundle anterior cruciate ligament reconstruction: Comparison among remnant preservation, resection, and absent groups

Purpose

The aim of this study was to verify the effects of a new remnant augmentation technique with anatomical double-bundle anterior cruciate ligament (ACL) reconstruction for postoperative clinical scores, anterior stability and frequency of complications compared to remnant removal and cases with remnant defects.

Methods

The 105 patients who underwent anatomical double-bundle ACL reconstruction were divided into three groups. If the remnant was a Crain I-III type, remnant-preserving bone tunnel creation was attempted. After the creation of the bone tunnel, good continuity was maintained in 34 patients (preserved group). Due to lost continuity, the remnant was resected in 26 patients (resected group). No identifiable remnant continuity remained (Crain IV) in 45 patients (absent group). The Lysholm knee score, Tegner activity scale, International Knee Documentation Committee (IKDC) subjective score, anterior stability measured using the KT-1000 arthrometer at 2 years postoperatively, and frequency of complications were compared among the three groups. Univariate and multiple linear regression analysis were performed to clarify the factors affecting postoperative anterior stability.

Results

The Lysholm knee score, Tegner activity scale, IKDC subjective score, and frequency of complications were not significantly different among the groups. The mean side-to-side difference of anterior stability was significantly better in the preserved group (0.3 ± 1.6 mm) compared to the resected group (1.6 ± 2.3 mm, p = 0.003) and absent group (1.6 mm ± 1.7, p = 0.009). The multiple linear regression analysis showed remnant preservation significantly related to postoperative anterior stability.

Conclusion

Although there were no differences in clinical scores, the ACL reconstruction with new preservation technique showed good anterior stability and no difference in the frequency of complications.

Assessment of thickness of in vivo autograft tendons around the knee and its correlation with anthropometric data, thickness of patella and anterior cruciate ligament tibial foot print diameter

Inadequate diameters of the autograft tendons are known to be a major cause of graft failure in ligament reconstruction. The purpose of the study was to measure the in-vivo thickness of the available autograft options around the knee and to seek a correlation between the thickness of the tendons and the anthropometric data, patellar thickness and anterior cruciate ligament (ACL) footprint sagittal diameter. Magnetic resonance imaging of 104 consecutive patients with suspected knee injuries were utilized for measurement of the in vivo thickness of pes anserinus tendon (diameter and cross-sectional area [CSA]), patellar tendon (PT) and quadriceps tendon (QT). Pearson’s coefficient was used to find out the relationship between the tendon thickness and anthropometric data, thickness of patella and ACL tibial foot print sagittal diameter. The mean diameters and CSA of the semitendinosus tendon (ST) and gracilis tendon (GT) were 3.77±0.49 mm, 11.62±1.62 mm² and 2.87±0.27 mm, 6.64±1.18 mm² respectively. QT and PT thicknesses were 7.36±0.87 mm and 4.50±0.62 mm respectively. Height and the patellar thickness were seen to have moderate correlation with ST and PT thickness. Weak correlation was seen between the other anthropometric variables and tendon thickness. Magnetic resonance imaging (MRI) assessment of tendon sizes is a reliable method with good inter and intra-rater agreement. Assessment of these anatomical structures with help of MRI would be helpful in preoperative planning and can help in identifying those patients at risk of having smaller tendons.

Developmental changes in ACLs and semitendinosus tendons dimensions according to age in children

PURPOSE

Managing anterior cruciate ligament (ACL) injuries in skeletally immature patients remains difficult. The main aim of this study was to retrospectively compile normative data on the cross-sectional area (CSA) of the semitendinosus tendon (ST) and the diameter of the ACL in children and young adults.

METHODS

Knee magnetic resonance imaging (MRI) examinations were performed for a 2-year period in 132 patients (83 female and 49 male patients). The mean age was 14.9 years (8-18 years). Measurements of the ST CSA were performed on axial views in greyscale by two independent researchers. The ACL diameter was measured as well.

RESULTS

The results show the CSA of the ST was related to age, and its growth was not linear. The highest growth rate of the CSA of the ST occurred at age 12-13 at the level of the femoral growth plate and at the level of the tibial plateau. The growth of the ACL diameter was linear until 18 years of age.

CONCLUSIONS

ST growth (measured in CSA increments) is almost complete at the age of 13, even though the growth is not linear. ACL growth measured in diameter increments proceeds linearly from 8 to 18 years of age. MRI is a clinically useful tool for assessing hamstring tendon grafts preoperatively.

LEVEL OF EVIDENCE

Level III, diagnostic studies.

Smaller cross-sectional areas of the hamstring tendon measured from preoperative ultrasonography are likely to need additional gracilis harvesting for double-bundle anterior cruciate ligament reconstructions

BACKGROUND/PURPOSE

Hamstring tendon autografts are commonly used for double-bundle anterior cruciate ligament reconstruction (DB-ACLR). If the volume of the semitendinosus (ST) tendon is insufficient, the gracilis (G) tendon is also harvested. Additional harvesting of the G autograft can affect patients' short-term postoperative outcome, such as muscle recovery; thus, preoperative information about whether an additional G autograft is needed would be useful. The purpose of this study was to investigate whether preoperative measurement of the ST tendon using ultrasonography could inform the intraoperative decision to harvest the G tendon.

METHODS

We enrolled 20 patients (13 men and seven women) who underwent DB-ACLR between October 2017 and March 2019. The mean patient age was 28.5 years. The ipsilateral ST tendon was measured using ultrasonography before surgery. Measurements included the diameter and breadth of the short-axis image. The cross-sectional area (CSA) was calculated from these measurements. During surgery, when two grafts with diameters of ≥ 5.0 mm could not be made, the G tendon was also harvested. Patients were categorized into two groups: the ST group where only the ST tendon was harvested, and the semitendinosus gracilis tendon (STG) group where the ST and G tendons were both harvested. The CSA value was compared between the two groups, and the cutoff value was calculated.

RESULTS

In the ST group (n = 8), the mean diameter and breadth of the semitendinosus tendon were 4.21 and 2.34 mm, respectively. In the STG group (n = 12), the mean diameter and breadth of the ST tendon were 3.39 and 1.78 mm, respectively. The CSAs calculated for the ST group and the STG group were 7.74 mm² and 4.79 mm², respectively. A cutoff value of 7.0 mm² was found to correspond to a specificity and sensitivity to harvest the G tendon of 87.5% and 75.0%, respectively.

CONCLUSIONS

The preoperative CSA of the ST tendon determined using ultrasonography can, therefore, be informative for deciding whether to harvest the G tendon for DB-ACLR. The results of this study provide valuable information for graft selection in anterior cruciate ligament reconstruction.

LEVEL OF EVIDENCE

IV (Retrospective case series design).

Can we predict the graft diameter for autologous hamstring in anterior cruciate ligament reconstruction?

To achieve in the reconstruction of the anterior cruciate ligament a graft with strength, tension and low comorbidity is fundamental. An emerging concept is that a graft diameter of less than 7mm carries a greater risk of re-rupture and instability. Consequently, different methods are being sought to predict intra-surgical size. The objective is to predict the size of the hamstring graft by measuring the area of the semitendinous and gracilis tendon with magnetic resonance imaging (MRI).

METHODOLOGY

We carried out an observational retrospective study of 56 patients. They underwent anterior cruciate ligament reconstruction with 4-GST hamstring graft. The parameters evaluated were anthropometric data, hamstring graft diameter, area of gracilis and semitendinosus tendon in MRI. The measurements were made by three independent evaluators.

RESULTS

The mean diameter of the intrasurgical graft was 8.46mm, in the MRI the area of the gracilis was 8,875mm and the semitendinosus area was 13,068mm. Their mean was 22.12 for the automatic measurement and 21.53 for the manual measurement. The interobserver correlation was regular for the automatic measurement (ICC = 0.595) and low for the manual measurement (ICC = 0.446). The result of the intraobserver correlation was excellent (ICC = 0.917). We did not obtain a statistical correlation between the measurement of areas and the increase of the graft diameter (R = 0.069, P = .63).

CONCLUSION

We determined with our results that the intrasurgical graft size is not predictable with the measurement of the area of the gracilis and semitendinosus tendon on the MRI.

Tibial tunnel enlargement after anatomic anterior cruciate ligament reconstruction with a bone-patellar tendon-bone graft. Part 2: Factors related to the tibial tunnel enlargement

BACKGROUND

Factors related to tunnel enlargement after anterior cruciate ligament (ACL) reconstruction should be evaluated by multivariate analysis, because the phenomenon has multifactorial characteristics. The purpose of this study was to elucidate the factors related to the tibial tunnel enlargement rate after anatomic ACL reconstruction with a bone-patellar tendon-bone (BTB) graft using multivariate analysis.

METHODS

Eighteen patients with unilateral ACL rupture were included. The anatomic rectangular-tunnel (ART) ACL reconstruction with a BTB autograft was performed. 3D CT models of the tibia, the tibial tunnel, and the bone plug at 3 weeks and 1 year after surgery were reconstructed and superimposed using a surface registration technique. The cross-sectional area (CSA) of the tibial tunnel perpendicular to the tunnel axis was evaluated at the aperture. The CSA was measured at 3 weeks and 1 year after surgery, and the tunnel enlargement rate at the aperture was calculated. Multiple linear regression analysis was performed to detect the significantly related factors to the tibial tunnel enlargement rate at the aperture among potential factors consisting of preoperative demographic factors and predisposing factors with the tibial tunnel.

RESULTS

The tibial tunnel enlargement rate at the aperture was 21.9 ± 14.1% (mean ± standard deviation). Multiple linear regression analysis detected the tendon length inside the tunnel as a significantly independent factor related to the tibial tunnel enlargement rate at the aperture (standardized β = 0.726, P = 0.008). There was no significant relationship between the tibial tunnel enlargement rate at the aperture and postoperative side-to-side difference (SSD) of the anterior knee laxity or Tegner activity level scale under single linear regression analysis.

CONCLUSION

The greater tendon length inside the tunnel was independently related to the higher tibial tunnel enlargement rate at the aperture 1-year after anatomic ACL reconstruction with a BTB graft under multiple linear regression analysis.

Reliability and Validity of Ultrasonography for Measurement of Hamstring Muscle and Tendon Cross-Sectional Area

The purpose of this study was to determine the reliability and validity of ultrasonography for measurement of hamstring muscle and semitendinosus (ST) tendon cross-sectional area (CSA). On two consecutive days, muscle anatomical CSA (ACSA) and ST tendon CSA were measured at standardized positions (30%-80% of thigh length; half the distance from the distal muscle-tendon junction to the popliteal crease) on 12 legs using ultrasonography and compared with corresponding magnetic resonance imaging measures. Inter-day intraclass correlation coefficients were good-to-excellent (0.882-0.996) for all assessed muscle and tendon sites. The limits of agreement widths were narrowest (range: 17%-52%) when muscle ACSA was large but were wide at sites with relatively small ACSA (≤184%) and for ST tendon CSA (range: 72%). Results suggest ultrasound-based measures of individual hamstring muscle maximal ACSA are reliable and valid and ST tendon CSA measures are reliable but require comparison with cadaveric or intra-operative measurements to verify validity.

Prediction of Autograft Hamstring Size for Anterior Cruciate Ligament Reconstruction Using MRI

BACKGROUND

Hamstring autografts with a diameter of less than 8 mm for ACL reconstruction have an increased risk of failure, but there is no consensus regarding the best method to predict autograft size in ACL reconstruction.

QUESTIONS/PURPOSES

(1) What is the relationship between hamstring cross-section on preoperative MRI and intraoperative autograft size? (2) What is the minimum hamstring tendon cross-sectional area on MRI needed to produce an autograft of at least 8 mm at its thickest point?

METHODS

This was a retrospective cohort study of 68 patients. We collectively reviewed patients who underwent ACL reconstruction by three separate fellowship-trained surgeons at the Carilion Clinic between April 2010 and July 2013. We searched the patient records database of each surgeon using the keyword "ACL". A total of 293 ACL reconstructions were performed during that time period. Of those, 23% (68 patients) had their preoperative MRI (1.5 T or 3 T magnet) performed at the Carilion Clinic with MRI confirmation of acute total ACL rupture. Exclusion criteria included previous ACL reconstructions, multiligamentous injuries, and history of acute hamstring injuries.After applying the exclusion criteria, there were 29 patients in the 1.5 T magnet group and 39 in the 3 T group. Median age (range) was 29 years (12 to 50) for the 1.5 T group and 19 years (9 to 43) for the 3 T group. The patients were 41% female in the 1.5 T group and 23% female in the 3 T group. Use of 1.5 T or 3 T magnets was based on clinical availability and scheduling. The graft's preoperative cross-sectional area was compared with the intraoperative graft's diameter. The MRI measurements were performed by a single musculoskeletal radiologist at the widest point of the medial femoral condyle and at the joint line. Intraoperative measurements were performed by recording the smallest hole the graft could fit through at its widest point. Pearson's correlation coefficients were calculated to determine the relationship between graft size and tendon cross-sectional area. A simple logistic regression analysis was used to calculate the cutoff cross-sectional areas needed for a graft measuring at least 8 mm at its thickest point. Intrarater reliability was evaluated based on re-measurement of 19 tendons, which produced an overall intraclass correlation coefficient (ICC) of 0.96 95% (CI 0.93 to 0.98). A p value < 0.05 was considered significant.

RESULTS

In general, the correlation between MRI-measured hamstring thickness and hamstring graft thickness as measured in the operating room were good but not excellent. The three measurements that demonstrated the strongest correlation with graft size in the 1.5 T group were the semitendinosus at the medial femoral condyle (r = 0.69; p < 0.001), the semitendinosus and gracilis at the medial femoral condyle (r = 0.70; p < 0.001), and the mean semitendinosus and gracilis (r = 0.64; p < 0.001). These three measurements had correlation values of 0.53, 0.56, and 0.56, respectively, in the 3 T MRI group (all p values < 0.001). To create an 8-mm hamstring autograft, the mean semitendinosus plus gracilis cutoff values areas were 18.8 mm and 17.5 mm for the 1.5 T and 3.0 T MRI groups, respectively.

CONCLUSIONS

Imaging performed according to routine knee injury protocol can be used to preoperatively predict the size of hamstring autografts for ACL reconstructions. In clinical practice, this can assist orthopaedic surgeons in graft selection and surgical planning.

LEVEL OF EVIDENCE

Level II, diagnostic study.

Preoperative sonographic measurement can accurately predict quadrupled hamstring tendon graft diameter for ACL reconstruction

PURPOSE

Previous studies reported sonography was inferior to MRI to predict hamstring tendon graft diameter for ACL reconstruction. This study aimed to investigate the correlation between intraoperative hamstring tendon graft diameter and its preoperative measurement using different sonographic scanning protocol from previous studies.

METHODS

Two cadaveric knees were utilized for validation. Sonographically guided gracilis tendon (G) and semitendinosus tendon (ST) injections were performed at myotendinous junction of sartorius using colored latex and then dissection was performed. In the clinical studies, 28 patients underwent primary ACL reconstruction were enrolled. Cross-sectional area (CSA) of G and ST were measured at myotendinous junction of Sartorius. The diameter of doubled G (2G), doubled ST (2ST) and quadrupled ST + G (4STG) were intraoperatively measured using graft sizing devices with 0.5-mm increments.

RESULTS

Cadaveric dissection showed the presence of latex on the surface of G and ST at myotendinous junction of Sartorius in all specimens. In the clinical studies, CSA of G, ST, and ST + G significantly correlated with diameter of 2G (r = 0.464, p = 0.039), 2ST (r = 0.712, p < 0.001), and 4STG (r = 0.792, p < 0.001), respectively. As a result of the simple linear regression analysis, 4STG diameter could be predicted by the following formula: 4.345 + 0.210 × CSA. The differences between calculated diameter by this formula and intraoperative 4STG diameter were within ± 0.5 mm in 89.3% (25/28) of subjects.

CONCLUSIONS

The diameter of 2ST and 4STG can be reliably predicted based on sonographic CSA measurement preoperatively. Sonography is a cost-effective alternate to repeat MRI to predict hamstring graft diameter preoperatively.

LEVEL OF EVIDENCE

Diagnostic study; Level II.

A review of methods to measure tendon dimensions

Tendons are soft tissues of the musculoskeletal system that are designed to facilitate joint movement. Tendons exhibit a wide range of mechanical properties matched to their functions and, as a result, have been of interest to researchers for many decades. Dimensions are an important aspect of tendon properties.

Change in the dimensions of tissues is often seen as a sign of injury and degeneration, as it may suggest inflammation or general disorder of the tissue. Dimensions are also important for determining the mechanical properties and behaviours of materials, particularly the stress, strain, and elastic modulus. This makes the dimensions significant in the context of a mechanical study of degenerated tendons. Additionally, tendon dimensions are useful in planning harvesting for tendon transfer and joint reconstruction purposes.

Historically, many methods have been used in an attempt to accurately measure the dimensions of soft tissue, since improper measurement can lead to large errors in the calculated properties. These methods can be categorised as destructive (by approximation), contact, and non-contact and can be considered in terms of in vivo and ex vivo.

Predicted quadriceps vs. quadrupled hamstring tendon graft size using 3-dimensional MRI

BACKGROUND

The objective of this study is to (1) compare the predicted cross-sectional area and diameter between quadriceps tendon and quadrupled hamstring autografts, and (2) assess the predicted size of the quadriceps tendon graft in patients with hamstrings that are insufficient for use in ACL reconstruction.

METHODS

A retrospective review of 54 knee 3D MRIs was conducted. Quadriceps tendon graft area was defined as a one-centimeter wide area of quadriceps tendon, measured three centimeters above the patella perpendicular to tendon axis. Quadrupled hamstring graft area was defined as double the combined areas of the gracilis and semitendinosus tendon, measured three centimeters above the joint line perpendicular to tendon axis. Pearson correlation was used to compare the quadriceps tendon and quadrupled hamstring grafts.

RESULTS

Mean cross-sectional area of quadrupled hamstring and quadriceps tendon grafts were 47.2 mm² and 84.4 mm² respectively. A statistically significant positive correlation exists between quadrupled hamstring graft and quadriceps tendon graft cross-sectional area (r = 0.41; p = 0.002). Nine of the 54 patients had predicted quadrupled hamstring grafts deemed insufficient for use in ACL reconstruction (<8 mm diameter). All of these patients had predicted quadriceps tendon graft diameters >8 mm.

CONCLUSION

There is a positive correlation between predicted quadriceps tendon and quadrupled hamstring grafts. While 17% of patients in this series had predicted insufficient quadrupled hamstring grafts, all of the patients had predicted quadriceps tendon grafts of sufficient size for ACL reconstruction. Quadriceps tendon grafts are a viable alternative in patients at-risk for insufficient quadrupled hamstring grafts.

LEVEL OF EVIDENCE

IV.

Correlation of intra-operative hamstring autograft size with pre-operative anthropometric and MRI measurements

The purpose of this study was to compare various pre-operative methods of estimating intra-operative hamstring autograft size. A retrospective review was completed on 74 patients who had an anterior cruciate ligament reconstruction performed using a quadruple-looped hamstring autograft from July 2007-April 2015 at a single institution. A positive correlation was observed between intra-operative graft size and pre-operative imaging using two methods of MRI measurements. Correlation existed between hamstring size and patient height and weight, but not age or BMI. Thus, pre-operative MRI and anthropometric measurements can be used to estimate intra-operative hamstring graft size.

Estimating Lengths of Semitendinosus and Gracilis Tendons by Magnetic Resonance Imaging

PURPOSE

To determine whether preoperative magnetic resonance imaging (MRI) can help predict the tendon-only length of the semitendinosus (ST) and the gracilis (G).

METHODS

The distance from the tibial insertion to the distal-most aspect of the musculotendinous junction (MTJ) of the ST and G was estimated on preoperative MRI scans of patients undergoing primary anterior cruciate ligament (ACL) reconstruction with single-bundle, quadruple-stranded hamstring autograft. This MRI tendon-only length, measured by a musculoskeletal radiologist blinded to surgical findings, was compared to the actual tendon-only length measured upon harvesting each tendon.

RESULTS

Among the 42 patients comprising the study population, there was very strong correlation between the estimates of tendon-only length made by MRI and surgical measurements for both the ST (Spearman coefficient = 0.83; P < .0001) and the G (Spearman coefficient = 0.82; P < .0001). The difference between MRI and surgical measurements did not exceed 3 cm for any of the 84 harvested hamstring tendons. Bland-Altman plots confirmed agreement between the 2 measurement methods. There was also strong correlation between the surgically measured tendon-only length of the ST and its G counterpart (Spearman coefficient = 0.68; P < .0001).

CONCLUSIONS

MRI estimates of tendon-only length for both the ST and G very strongly correlate with operative measurements of these lengths; the discrepancy between these 2 measurement methods was found to not exceed 3 cm when the MTJ of these tendons is visible on MRI scans.

LEVEL OF EVIDENCE

Level III, comparative study.

Ultrasonography for evaluation of hamstring tendon diameter: is it possible to predict the size of the graft?

Objective

Perform the preoperative measurement of the hamstring tendons using ultrasound imaging, validating and correlating the measured value with that found during surgical reconstruction of the ligament.

Methods

A cross-sectional study was carried out with 24 patients who underwent ultrasonographic measurement of the semitendinosus and gracilis muscle tendons and were subsequently submitted to surgical reconstruction of the ACL, with ipsilateral semitendinosus and gracilis tendon grafting.

Results

The patients’ ages ranged from 16 to 43 years, with a mean of 24.8 years (SD = 8.4 years), 79.2% were men, and the distribution by side was 41.7% right knees and 58.3% left knees. A non-significant correlation coefficient was found between the area calculated by ultrasound (2 × semitendinosus area + 2 × gracilis area) and the intraoperative measurement (r = 0.16; p = 0.443). No evidence of a difference between intraoperative measurements <8 mm and ≥8 mm was found for the area calculated by the ultrasound (p = 0.746). The difference observed between the groups was −0.01 (95% CI: −0.09 to 0.07).

Conclusion

Preoperative ultrasound imaging of the semitendinosus and gracilis tendons does not present a statistically significant correlation with the intraoperative measurement of the quadruple hamstring graft for ligament reconstruction.

Multiple extensor tendons reconstruction with hamstring tendon grafts and flap coverage for severe dorsal hand injuries

Treatment of patients with traumatic loss of skin and multiple extensor tendons on the dorsum of the hand is a challenge. The aim of this study was to assess the outcome after reconstruction of soft tissues and multiple extensor tendons in patients who suffered traumatic loss of skin and multiple extensor tendons. Ten patients were enrolled in the study. These patients underwent single-stage reconstruction with autogenous hamstring tendon grafts for multiple extensor tendon defects and fasciocutaneous flaps for coverage of dorsal hand defects. In total, 25 tendons (2 tendons in 5 patients and 3 tendons in 5 patients) were reconstructed. The semitendinosus tendon was used in all patients and the gracilis tendon was added in five patients for tendon reconstruction. Total tendon length requiring reconstruction was between 9cm and 31cm. Free anterolateral thigh flaps were used in six patients and reverse pedicled forearm flaps were used in four patients. According to Miller's scoring system, 8 fingers had excellent results, 12 fingers had good results and 5 fingers had fair results at the final follow-up. Hamstring tendons can be used satisfactorily for primary reconstruction of multiple digital extensor tendons due to their availability and compatibility, with a fasciocutaneous flap.

LEVEL OF EVIDENCE

IV.

Relationship of Musculotendinous Junction Location to Harvested Semitendinosus and Gracilis Tendon Length

Background:

Harvested hamstring tendon length has received scant attention in published anterior cruciate ligament (ACL) reconstruction literature, yet length can limit the ability to increase graft diameter by folding the tendon over more than once. Indeed, some ultrashort tendons may be too short to yield a clinically useful graft after being folded over just once. Ultimately, the total length of a harvested hamstring tendon may depend on the length of the tendon distal to its musculotendinous (MT) junction.

Purpose:

To compare the lengths of harvested hamstring tendons to the location of the MT junction to help predict abnormally short tendon harvest.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Eighty-four consecutive patients undergoing primary ACL reconstruction using hamstring tendon autografts underwent intraoperative measurement of the total length of each harvested semitendinosus (ST) and gracilis (G) tendon, as well as the distance from the MT junction to that tendon’s distal end (ie, the “tendon-only” length).

Results:

The ratio of the tendon-only portion to total harvested tendon length averaged 0.52 (range, 0.39-0.71) for the ST and 0.52 (range, 0.43-0.71) for the G, suggesting a 95% chance of harvesting a tendon <15 cm in length for the tendon-only portion is <6.45 cm for ST or <6.75 cm for G tendons. There was moderate correlation between the lengths of harvested ST and G tendons with patient height as well as with the diameter of the combined, quadruple-stranded graft.

Conclusion:

The ratio of the tendon-only length to total harvested length for both the ST and G appear to range from approximately 0.4 to 0.7. Patients with abnormally distal MT junctions of either their ST or G are likely to have an abnormally short harvest of that tendon, even in the absence of technical harvesting error.

Cross-sectional area of hamstring tendon autograft after anatomic triple-bundle ACL reconstruction

PURPOSE

The purpose was to evaluate the cross-sectional area changes in hamstring tendon autografts up to 5 years after the anatomic triple-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

A total of 178 MRI scans from 139 patients (35 males, 104 females, mean age 30.4 years) with the anatomic triple-bundle ACL reconstructions were obtained to evaluate the cross-sectional area of the ACL grafts. They were classified into seven groups according to the period from reconstruction to MRI evaluation: Group -2 months (m.), Group 3-6 m., Group 7-12 m, Group 1-2 years (y.), Group 2-3 y., Group 3-4 y., and Group 4 y.-. Intra-operatively, the cross-sectional area of the graft was measured directly using a custom-made area micrometre. Post-operatively, the cross-sectional area of the grafts' mid-substance was measured with oblique axial MRI slices perpendicular to the long axis of the grafts using a digital radiology viewing program. The percent increase in the cross-sectional area was calculated by dividing the post-operative cross-sectional area by the intra-operative cross-sectional area.

RESULTS

The mean percent increase in the cross-sectional area in Groups -2 m., 3-6 m., 7-12 m., 1-2 y., 2-3 y., 3-4 y., and 4 y.- was 105.7 ± 14.0, 134.9 ± 20.0, 137.3 ± 27.8, 129.4 ± 22.2, 124.1 ± 20.4, 117.8 ± 16.9, and 117.1 ± 17.2 %, respectively. The percent increase in Groups 3-6 m., 7-12 m., and 1-2 y. was significantly greater than in Group -2 m., while that in Group 4 y.- was significantly less than in Group 7-12 m.

CONCLUSIONS

The cross-sectional area of the hamstring tendon autografts after the anatomic triple-bundle ACL reconstruction increases over time up to 1 year post-operatively, decreases gradually thereafter, and reaches plateau at around 3 years.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Regression modelling combining MRI measurements and patient anthropometry for patient screening and prediction of graft diameter in hamstring autograft arthroscopic ACL reconstruction

Background

Previous studies have associated anthropometric data and pre-operative hamstring tendon measurements to intraoperative graft diameter for hamstring autograft ACL reconstruction, although an integrated model has yet to be described. The aim of this study was to present such a predictive model for quadrupled semitendinosus (4-ST) and doubled semitendinosus-gracilis (4-STG) graft constructs combining anthropometry (height and weight) and preoperative measurements of tendon as predictors.

Methods

ACL reconstructions using 4-STG and 4-ST were retrospectively reviewed. The outlines of the semitendinosus and gracilis tendons were identified manually in the axial slice of a preoperative T2 weighted MRI using a region-of-interest tool. Regression analysis using intraoperative graft diameter as the dependent variable was performed with tendon cross-sectional area (XSA), gender and height as predictors.

Results

108 ACL reconstructions in 107 patients were examined, 75 of which were performed using the 4-STG construct, and 33 which employed the 4-ST construct. The mean graft diameter in the 4-ST group (8.6 ± 0.8 mm) was significantly (p < 0.001) greater than the 4-STG group (7.9 ± 0.7 mm). Female gender and 4-STG graft construct were associated with increased risk of graft diameter <8 mm. Predictive models of graft diameter were accurate to ±1 mm for both construct types.

Conclusions

An integrated method for assessing patient risk of producing a diminutive graft diameter and planning augmentation in select cases has been presented. The present findings describe a validated predictive model that builds on previous univariable analyses. Further investigation of larger samples, including factors associated with graft preparation, is required to improve model accuracy for routine clinical application.

Level of evidence

IV, Retrospective Cohort Study

Using pre-operative MRI to predict intraoperative hamstring graft size for anterior cruciate ligament reconstruction

PURPOSE

Large variation in tendon size between individuals makes hamstring graft diameter for anterior cruciate ligament (ACL) reconstruction unpredictable. Inadequate graft diameter may necessitate an alternative source of tissue requiring pre-operative planning. The purpose of this study was to determine whether magnetic resonance image (MRI) measurements and clinical anthropometric data are predictive of hamstring tendon graft diameter.

METHODS

Data from 109 patients having ACL reconstruction with semitendinosus-gracilis (STGT) autograft were retrospectively evaluated. Cross-sectional area (CSA) of the gracilis tendon (GT) and semitendinosus tendon (ST) were determined from pre-operative MRI scans. Variables included pre-operative height, weight, body mass index (BMI), age and gender; and intra-operative graft diameter.

RESULTS

Correlations between anthropometric variables, hamstring tendons CSA and intra-operative graft diameter were calculated. Multiple stepwise regression was performed to assess the predictive value of these variables to graft diameter. Sensitivity and specificity were calculated to evaluate the utility of MRI CSA measurements in accurately identifying inadequate graft diameter (<8 mm). All anthropometric variables were positively correlated with intraoperative graft diameter (p < 0.01). Semitendinosus-gracilis tendon CSA (p < 0.001) and STGT CSA and weight (p < 0.001) were significantly predictive models of graft diameter. Sensitivity and specificity were 79 and 74 %, respectively.

CONCLUSION

The strongest indicators of a four-stranded STGT graft for primary ACL reconstruction were STGT CSA on MRI plus weight. Measurement of graft diameter can be performed pre-operatively via MRI to identify tendons that may be of inadequate size for ACL reconstruction. This can assist with surgical planning to determine the most appropriate graft choice.

LEVEL OF EVIDENCE

III.

Preoperative magnetic resonance imaging evaluation of semitendinosus tendon in anterior cruciate ligament reconstruction: Does this have an effect on graft choice?

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction with ST autograft is sometimes unsuccessful because of harvested thin graft. Magnetic resonance imaging (MRI) can be a useful tool to evaluate the thickness of the graft. This study is performed to evaluate whether there is any correlation between diameters and cross-sectional area (CSA) of the semitendinosus tendon (ST) on the preoperative magnetic MRI and the diameter of the 4-stranded ST autograft in ACL reconstruction.

MATERIALS AND METHODS

Seventy patients who underwent single-bundle ACL reconstruction with 4-stranded ST for full-thickness ACL ruptures were included in this study. Anteroposterior (AP) and mediolateral (ML) diameters of ST at the levels of the joint line (JL) and femoral physeal line (PL), and also CSA at these levels were measured on T2-weighted fat-suppressed MRI examinations. The data obtained were compared with intraoperatively measured diameters of 4-stranded ST autograft. Correlations between variables were evaluated using Spearman's rho. Receiver operating characteristic and area under the curve statistics were used to evaluate the cut-off value for the correlation between 4-stranded ST graft diameter of 8 mm and CSA (mm²) on MRI.

RESULTS

On MRI measurements, no correlation was found between AP diameters at the level of the JL and 4-stranded ST diameter (P = 0.180). However, correlations were found between diameter of 4-stranded ST and ML diameter at the level of JL (P = 0.003) and PL (P = 0.002), AP diameter at the level of the PL (P = 0.009), CSA at the level of the JL (P < 0.001) and at the level of PL (P < 0.001). Correlation between the diameter of 4-stranded ST and CSA at both levels was more significant than that between AP-ML diameters of ST and diameter of autograft. The cut-off value for the 8 mm diameter CSA of 4-stranded ST was 5.9 mm² at the JL and 8.99 mm² at the PL.

CONCLUSION

Preoperative MRI evaluation of CSA at the JL of the ST is a reliable parameter to predict graft size. Other graft alternatives should better be considered if the CSA of ST is <5.9 mm² at the level of the JL.

Do graft diameter or patient age influence the results of ACL reconstruction?

PURPOSE

Hamstring tendons are commonly used as a graft source for ACL reconstruction. This study seeks to determine whether either the diameter of the tendon graft or the age of the patient influences the outcome of the ACL reconstruction when measured using a standard, previously validated laxity measurement device.

METHODS

This is a retrospective study of 88 patients who underwent ACL reconstruction with a short, quadrupled tendon technique, using the semitendinosus ± gracilis tendons. Patients included in this study were sequential, unilateral, complete ACL ruptures. The patients were followed for a minimum of 1 year postoperatively, with a mean follow-up of 26 months. Patients were divided into three groups according to the diameter (Ø) of the graft: group 1 (32 patients): 8 mm ≤ Ø ≤ 9 mm; group 2 (28 patients): 9 mm < Ø ≤ 10 mm; and group 3 (28 patients): Ø > 10 mm. Three groups with differential laxity at 134 N (Δ134 = healthy side vs. operated side) measured with the laximeter GNRB(®) were compared. The risk of residual laxity (OR) between the three groups taking age, gender, BMI and meniscus status into account was calculated. A side-to-side laxity >3 mm was considered as a residual laxity.

RESULTS

The mean patient age at the time of reconstruction was 29.4 years. The three groups were comparable. Postoperative Δ134 was 1.50 ± 1.3, 1.59 ± 1.5 and 2 ± 1.7 mm for groups 1 through 3, respectively. Δ134 > 3 mm was observed in three patients in group 1, four patients in group 2 and nine patients in group 3. As compared to group 1, OR was 1.46 (95 % CI 0.35-6.05) and 3.31 (95 % CI 0.89-12.34) in groups 2 and 3, respectively. Adjustment for age, gender, BMI and meniscus did not change the estimates [OR 1.44 (95 % CI 0.34-6.16) and 3.92 (95 % CI 1-15.37)] in groups 2 and 3, respectively. Patients younger than 20 had a significantly higher average postoperative laximetry (2.4 ± 1.5 mm) compared to those aged 20 years and over (1.5 ± 1.5 mm) (p = 0.03), regardless of the diameter of the graft.

CONCLUSION

The diameter of the graft between 8 and 10 mm does not affect the laximetric results of an ACL reconstruction. Therefore, there does not appear to be a benefit to harvesting and adding further tissue to increase the diameter of the graft above 10 mm. Patients younger than 20 represent a population at risk of graft elongation. In these patients at risk, postoperative management needs to be modified (delayed weight bearing, articulated splinting, slower rehabilitation) in the first months.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Prediction of flexor tendon graft diameter in reconstruction of the anterior cruciate ligament by means of magnetic resonance imaging

OBJECTIVE

To evaluate the diameter of the flexor tendons in preoperative magnetic resonance imaging (MRI) examinations and compare this with the diameter of the graft obtained intraoperatively.

METHODS

This was a retrospective longitudinal epidemiological study. Forty-four patients were eligible for the study and their MRI examinations and surgical data were evaluated. The tendons were measured on MRI across their largest diameter in the axial plane, using the medial epicondyle of the femur as the slice level. In the surgery, routine graft preparation was performed, consisting of folding the gracilis and semitendinosus tendons to form a four-strand graft. Its measurement was recorded.

RESULTS

To evaluate the association between the variables, Pearson's correlation coefficient was estimated. A significant correlation was found between the measurements of the gracilis and semitendinosus tendons and the final diameter of the graft (p < 0.001). A ROC curve was fitted to the sum of the tendon diameters in order to determine a cutoff point associated with the graft diameter (≤8 mm or >8 mm). If the sum was greater than 5.28 mm, the chance of obtaining a graft larger than 8 mm would be 75%.

CONCLUSION

Measurement of the diameters of the gracilis and semitendinosus tendons through a preoperative MRI examination is a simple and effective way to predict the final size of the graft to be used in ACL reconstruction surgery.

Anterior Cruciate Ligament Reconstruction With Autologous Hamstring: Can Preoperative Magnetic Resonance Imaging Accurately Predict Graft Diameter?

Background:

Recent clinical investigations have identified inadequate autograft hamstring graft diameter (<8 mm) to be predictive of failure after reconstruction of the anterior cruciate ligament (ACL).

Purpose/Hypothesis:

The objective of this study was to determine the utility of preoperative magnetic resonance imaging (MRI) variables of the hamstring tendons for the prediction of graft diameter at the time of surgery. The hypothesis was that cross-sectional area (CSA) of the hamstring tendon measured on MRI could accurately predict graft diameter, and threshold measurements could be established to predict graft diameter at the time of surgery.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

A total of 84 consecutive skeletally mature patients prospectively enrolled in our ACL reconstruction patient registry were identified for study purposes. Patients were included if they underwent an MRI of the affected knee at our institution prior to ACL reconstruction with hamstring (HT) autograft. Graft preparation was performed via a standard quadrupled hamstring technique after harvesting both the gracilis and semitendinosus (4-GST). The smallest diameter end of the HT autograft was then utilized for measurement analysis. Total CSA was calculated for both hamstring tendons using the “region of interest tool” on the corresponding proton density–weighted axial image of the knee at the widest condylar dimension. Three independent reviewers measured the MRI scans so that intra- and interrater reliability of the measurements could be determined. A trend analysis was then undertaken to establish correlations between the MRI CSA and graft diameter. Predictive analysis was then performed to establish threshold MRI measurement values for specific graft diameters and determine whether any patient-specific factors would affect graft diameter (age, sex, and body mass index).

Results:

Mean patient age at the time of surgery was 36 years (range, 11-57 years). Intra- and interrater reliability measurements achieved near-perfect agreement for CSA measurements, with intraclass correlation coefficients (ICCs) of 0.994 and 0.932, respectively. Trend analysis demonstrated that increasing CSA correlated well with increasing overall diameter of the graft (P < .001). Receiver operating characteristic (ROC) curves were generated to evaluate threshold CSA measurements for various graft diameters. Maximum sensitivity values of 21.64, 25.25, and 28.256 mm² were established for the respective graft diameters of 8, 9, and 10 mm in the 4-GST group. Independent patient factors of younger age, shorter stature, and female sex were significantly associated with graft diameter (P = .019, .034, and .028, respectively).

Conclusion:

Preoperative MRI can be used to accurately predict quadrupled hamstring autograft diameter at the time of surgery. A total cross-sectional area of >22 mm² can reliably provide a graft diameter of >8 mm at the time of surgery.

Correlation between anthropometric data and length and thickness of the tendons of the semitendinosus and gracilis muscles used for grafts in reconstruction of the anterior cruciate ligament

Objective

Preoperative estimation of the length and diameter of the semitendinosus (ST) and gracilis (G) tendons can assist surgeons and allow them to have the opportunity to choose alternative grafts. The aim of this study was to investigate whether anthropometric measurements such as height, weight and body mass index (BMI) or the patient's age and sex have any correlation with the thickness and the length of ST and G tendons.

Methods

Data were gathered from 64 patients who underwent the surgical procedure of anterior cruciate ligament reconstruction using the tendons of the ST and G muscles as grafts, between June 2012 and August 2013. Variables such as age, sex, weight, height, body mass index (BMI) and length and diameter of the tendons of the ST and G muscles were analyzed.

Results

There was a positive correlation between the height and total diameter of the quadruple graft (r = 0.254; p = 0.043), total length of the ST tendon (r = 0.450; p < 0.01), diameter of the double ST (r = 0.270; p = 0.031), triple ST (r = 0.347; p = 0.005), length of G tendon (r = 0.249; p = 0.047) and diameter of the double-G (r = 0.258; p = 0.039). However, age (r = -0.015; p = 0.908), weight (r = 0.165; p = 0.193) and body mass index (r = 0.012; p = 0.926) showed no correlation.

Conclusion

Our results show that age, weight and BMI did not correlate with the diameter and length of the graft, while the height had a positive correlation with the total length of the flexor tendons and the diameter of the graft from the flexors (ST and G).

Half-peroneus-longus-tendon graft augmentation for unqualified hamstring tendon graft of anterior cruciate ligament reconstruction

BACKGROUND

In some situations, harvested hamstring tendon grafts are not qualified for anterior cruciate ligament (ACL) reconstruction. This study aimed to present a reinforcing method with additional half peroneus longus tendon (half-PLT) graft augmentation.

METHODS

Eight cases underwent ACL reconstruction with unqualified hamstring tendon grafts (diameter <7 mm) and were salvaged by additional half-PLT graft augmentation. The pivot shift test and KT-1000 tests were performed 3 years after surgery. Functional evaluation of subjective International Knee Documentation Committee (IKDC) and Lysholm scores was also done. In addition, Foot and Ankle Disability Index (FADI) scores were used to evaluate the function of the ankle donor site.

RESULTS

The diameter of unqualified four-strand hamstring tendon grafts was 6.2 mm on average (range, 6.0-6.5 mm). The average diameter of hamstring grafts with half-PLT augmentation was 9.6 mm (range, 9.5-10.0 mm). The pivot shift test was negative in all patients. No significant differences between normal and abnormal knees were found by KT-1000. The average IKDC score was 86.0 (range, 83 to 89), and the average Lysholm score was 84.4 (range, 80-90). The average FADI score for the donor sites of half-PLT was 135.8 (range, 134-136).

CONCLUSIONS

Additional half-PLT can successfully and safely reinforce unqualified hamstring tendon grafts for ACL reconstruction.

Anatomic ACL reconstruction: rectangular tunnel/bone-patellar tendon-bone or triple-bundle/semitendinosus tendon grafting

Anatomic ACL reconstruction is the reasonable approach to restore stability without loss of motion after ACL tear. To mimic the normal ACL like a ribbon, our preferred procedures is the anatomic rectangular tunnel (ART) technique with a bone-patellar tendon-bone (BTB) graft or the anatomic triple bundle (ATB) procedure with a hamstring (HS) tendon graft. It is important to create tunnel apertures inside the attachment areas to lessen the tunnel widening. To identify the crescent-shaped ACL femoral attachment area, the upper cartilage margin, the posterior cartilage margin and the resident's ridge are used as landmarks. To delineate the C-shaped tibial insertion, medial intercondylar ridge, Parson's knob and anterior horn of the lateral meniscus are helpful. In ART-BTB procedure which is suitable for male patients engaged in contact sports, the parallelepiped tunnels with rectangular apertures are made within the femoral and tibial attachment areas. In ATB-HS technique which is mainly applied to female athletes engaged in non-contact sports including skiing or basketball, 2 femoral and 3 tibial round tunnels are created inside the attachment areas. These techniques make it possible for the grafts to run as the native ACL without impingement to the notch or PCL. After femoral fixation with an interference screw or cortical fixation devices including Endobutton, the graft is pretensioned in situ by repetitive manual pulls at 15-20° of flexion, monitoring the graft tension with tensioners on a tensioning boot installed on the calf. Tibial fixation with pullout sutures is achieved using Double Spike Plate and a screw at the pre-determined amount of tension of 10-20N. While better outcomes with less failure rate are being obtained compared to those in the past, higher graft tear rate remains a problem. Improved preventive training may be required to avoid secondary ACL injuries.

Hamstring autograft size can be predicted and is a potential risk factor for anterior cruciate ligament reconstruction failure

PURPOSE

The purposes of this systematic review were (1) to determine whether there is a minimum hamstring autograft size for anterior cruciate ligament (ACL) reconstruction that significantly decreases the risk of failure and (2) to evaluate the methods to accurately and reliably predict the size of hamstring grafts.

METHODS

We performed a systematic review of Level III and IV studies using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. All studies assessing failure of quadrupled-strand autograft hamstring ACL reconstruction as a function of graft diameter with at least 1 year of follow-up and those that assessed the use of imaging or anthropometric patient-specific factors to predict hamstring autograft size were included.

RESULTS

We identified 4 clinical studies that directly compared graft size and failure rate. These correlated with a 6.8 times greater relative risk of failure if the graft diameter was equal to or less than 8 mm (P = .008). All 9 anthropometric-based prediction studies were able to significantly correlate at least 1 parameter with intraoperative graft size. Height was the most common correlation, with r = 0.45 (P < .00001). Five of 6 imaging-based prediction studies showed signification correlation, with r = 0.66 (P < .00001), between cross-sectional area and graft size. The most common method of imaging prediction was magnetic resonance imaging-derived cross-sectional area of both the semitendinosus and gracilis tendons.

CONCLUSIONS

On the basis of the available evidence, ACL reconstruction with a quadrupled-strand hamstring autograft with a diameter equal to or larger than 8 mm decreases failure rates. In addition, grafts larger than 8 mm decrease failure rates in patients aged younger than 20 years, a group identified to be at increased risk of failure. Both patient height and magnetic resonance imaging-derived cross-sectional area of the hamstring tendons can be used preoperatively to reliably predict the hamstring autograft diameter.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III and IV studies.

ACL ideal graft: MRI correlation between ACL and humstrings, PT and QT

Objective

The objective of this study was to measure in MRI scans, the size of the origin, insertion and length of the anterior cruciate ligament and possible graft for reconstruction surgery in case of injury. Besides this, there was a cross between statistical data to test the hypothesis of proportional relationship between these anatomical extent.

Materials and methods

52 MRI examinations performed between 2008 and 2011 were valued at random in a longitudinal retrospective epidemiological study. To measure the width of the ACL was used coronal oblique to the length of the sagittal section, for inserting the tibial coronal femoral insertion and was also used oblique coronal section.

Results

The average diameter of the ACL was 4.80 mm (3.1–8.3 mm), with a length of 3.8 cm (2.85–4.5 cm). The origin ranged from 9.7 mm to 15.4 mm. The average insertion on the tibia was 13.3 mm. The average diameter of the semi-tendinous was 4.38 mm and the average diameter was 3.42 mm gracilis. The quadriceps presented diameter of 7.67 mm, a length of 35.34 mm and 4.54 mm patellar tendon diameter and 26.62 mm in average length.

Conclusion

These data provide important information for the pre-operative surgeon, facilitating preoperative planning and providing viable alternatives and avoiding inadequate grafts.

Age, graft size, and Tegner activity level as predictors of failure in anterior cruciate ligament reconstruction with hamstring autograft

BACKGROUND

Patient age, Tegner activity level, and graft size could be factors that influence the outcome of anterior cruciate ligament reconstruction (ACLR) with hamstring autografts.

HYPOTHESIS

Decreased graft size, higher Tegner activity score, and younger age are associated with an increased failure rate of ACLR, represented by continued knee laxity and revision surgery.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 98 patients who had undergone ACLR with hamstring tendon autografts between 2000 and 2007 were identified from a computerized relational database. Inclusion criteria consisted of a minimum of 2 years of follow-up, all age groups, and all activity levels. Exclusion criteria consisted of treatment with other grafts or previous ligament surgery, previous ACL repairs, bilateral ACL injuries, and associated ligament tears. Failure was defined as a 2+ Lachman result, positive pivot shift, and 5-mm difference or more on KT-1000 arthrometer measurement.

RESULTS

Fifteen of the 98 ACLRs (15.3%) were defined as failures. Of the failures, 12 of 48 (25%) occurred in patients aged 25 years and younger, whereas 3 of 50 (6%) occurred in patients older than 25 years. There was a statistically significant association when comparing failure rate and age groups (P = .009); however, a significant association was not found between graft size and failure rate in the entire study population (P = .135) or within the different age groups (age ≤25 years vs. >25 years) based on failure rate (P = .390 and P = .165, respectively). No statistical significance was found when Tegner activity level and failure rate were compared in the overall study population (P = .463) or within age groups (≤25 years, P = .707; >25 years, P = .174).

CONCLUSION

In this study population, younger patients (≤25 years) demonstrated a higher failure rate compared with the over-25 age group. A statistically significant difference was not found in terms of graft size and activity level correlating with failure rate in ACL reconstruction with hamstring autograft.

How to improve the prediction of quadrupled semitendinosus and gracilis autograft sizes with magnetic resonance imaging and ultrasonography

BACKGROUND

Hamstring tendon grafts may have an unacceptable size for use in anterior cruciate ligament (ACL) reconstruction. Magnetic resonance imaging (MRI) has been proposed to predict the diameters of hamstring tendon grafts.

HYPOTHESIS

Preoperative ultrasonography (US) might reliably anticipate intraoperative 4-strand semitendinosus and gracilis tendon (4ST-GT) graft sizes similarly to MRI. An MRI evaluation of the hamstring tendons with a higher magnification may improve the accuracy of the method.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

A total of 33 patients undergoing ACL reconstruction with a 4ST-GT graft and MRI performed at our institution were included. The cross-sectional area (CSA) of each semitendinosus tendon (ST) and gracilis tendon (GT) was calculated preoperatively with US and with MRI under 2× and 4× magnification. Intraoperative measurement of the final diameter of the 4ST-GT using a closed-hole sizing block with 0.5-mm increments was made. Pearson correlation coefficients were calculated to determine the relationship between the final intraoperative graft diameter of the 4ST-GT and the CSA of the ST and GT measured with US and MRI with 2× and 4× magnification. Simple linear regression was also calculated to attempt to predict the graft diameter based on given measurements.

RESULTS

There were statistically significant correlations between the measured CSA with US and both MRI magnifications with the 4ST-GT diameter. However, MRI under 4× magnification showed a much higer correlation (0.86) than MRI under 2× magnification (0.54) or US (0.51). Final graft diameters ≥8 mm were observed in 80.8% of patients with a CSA >14 mm(2), in 76.9% of patients with a CSA >25 mm2, and in 96.2% of patients with a CSA >17 mm2 measured with US, 2× magnification of MRI, and 4× magnification of MRI, respectively.

CONCLUSION

Preoperative calculation of the CSA of the hamstring tendons with MRI and US can help to reliably estimate 4ST-GT grafts. In terms of correlation of the CSA with graft diameter, US was comparable to 2× MRI, but 4× MRI showed a much greater accuracy. Threshold values of the CSA of the ST and GT of 25 mm2, 17 mm2, and 14 mm2 with the 2× MRI, 4× MRI, and US methods, respectively, are needed to reliably predict a 4ST-GT graft with a minimum diameter of 8 mm.

Factors predicting hamstring tendon autograft diameters and resulting failure rates after anterior cruciate ligament reconstruction

PURPOSE

The purposes of this study are to confirm factors that affect the diameter of hamstring tendon autograft and to compare failure rates between the factors after anterior cruciate ligament (ACL) reconstruction.

METHODS

A total of 296 patients that underwent reconstruction using hamstring tendon autograft at our clinics for ACL injury between September 2005 and June 2008 were enrolled for this study. The diameters of gracilis and semitendinosus tendons (harvested from the affected knee) and four-strand graft tendon made by folding the gracilis and semitendinosus tendons in two layers were measured. Before operating, we recorded the age, height, weight, Body Mass Index (BMI), gender and athlete versus non-athlete identity of the subjects and checked their correlations with graft diameters. Patients that recorded a grade C or D on the International Knee Documentation Committee Knee Examination Form, as well as patients that underwent revision, were defined as failures and analysed by related factors.

RESULTS

The mean diameter was 1.5 mm ± 0.2 for gracilis tendon, 2.2 mm ± 0.3 for semitendinosus tendon and 7.2 mm ± 0.7 for graft tendon. Except for age, factors including height, weight, BMI, gender and athlete versus non-athlete identity were found to be significantly related to graft diameter. Correlation was strongest with height (p < 0.001). With respect to failure rates after ACL reconstruction, patients with a graft diameter of 8.0 mm or more demonstrated statistically better results than patients with a diameter of below 8.0 mm (p = 0.043). However, failure rates did not differ significantly with respect to other factors.

CONCLUSIONS

The diameter of hamstring tendon autograft may be different depending on height, weight, BMI and gender of the patient, as well as whether or not the patient is an athlete. Although we did not find statistically significant differences in failure rates after ACL reconstruction, this study demonstrated relatively better results in patients with a graft diameter of 8.0 mm or more.

LEVEL OF EVIDENCE

Case series, Level IV.

Cryopreservation with glycerol improves the in vitro biomechanical characteristics of human patellar tendon allografts

PURPOSE

To evaluate the in vitro biomechanical characteristics of patellar tendon ligaments (BTB) when stored as fresh frozen or as glycerol cryopreserved allografts.

METHODS

Seventy patellar tendons were harvested from 35 cadaveric human donors and randomly assigned into seven groups. Grafts in group FRESH were mechanically tested within 2 h of harvesting. FROZ-3, FROZ-6, and FROZ-9 were deep-frozen to -80 °C for 3, 6, and 9 months, respectively. Grafts in groups CRYO-3, CRYO-6, and CRYO-9 were initially incubated with 10% glycerol in a phosphate-buffered saline for 1 h and then stored in glycerol solution (10% glycerol in PBS) at -80 °C for 3, 6, and 9 months, respectively. Grafts were mechanically tested with two cycling modes (50-250 °N and 150-500 °N) and then loaded to failure.

RESULTS

Cryopreserved grafts demonstrated more consistent results and expressed lower elongation rates after both cycling loading protocols compared to their frozen counterparts at all storage times. During load-to-failure analysis, ultimate stiffness levels were predominantly higher (23.9-61.5%) in cryopreserved grafts compared with frozen grafts, and ultimate stress levels were 26% (13.3-47.7%) higher, regardless of the storage time. Moreover, cryopreserved grafts revealed similar ultimate elongation and uniformly higher ultimate stiffness and ultimate stress levels compared to fresh grafts.

CONCLUSION

The results of this in vitro study demonstrated superior mechanical properties of cryopreserved grafts compared to frozen grafts within a preservation period of 9 months. Cryopreservation with glycerol solution might be used to further improve the quality of preserved soft-tissue allografts.