The medial epicondyle of the distal femur is the optimal location for MRI measurement of semitendinosus and gracilis tendon cross-sectional area
Graft diameter ≥ 8 mm reduces the risk of failure after anterior cruciate ligament reconstruction (ALCR) with hamstring tendon autograft. Pre-operative measurement of gracilis (GT) and semitendinosus (ST) cross-sectional area using MRI has been utilized but the optimal location for measurement is unknown. The main purpose of this study was to examine the cross-sectional areas of GT + ST at different locations and develop a model to predict whether a doubled hamstring graft of GT + ST will be of sufficient cross-sectional area for ACLR.
A retrospective review was performed of 154 patients who underwent primary ACLR using doubled hamstring autograft. Cross-sectional area measurements of GT + ST on pre-operative MRI axial images were made at three locations: medial epicondyle (ME), tibiofemoral joint line (TJL), and tibial physeal scar (TPS) and calculated the correlation of intra-operative graft size for each location using the Pearson’s correlation coefficient. A receiver operating characteristic (ROC) established a threshold that would predict graft diameter ≥ 8 mm.
Measurement of GT + ST at the ME had a stronger correlation (r = 0.389) to intra-operative graft diameter than measurements at the TJL (r = 0.256) or TPS (r = 0.240). The ROC indicated good predictive value for hamstring graft diameter ≥ 8 mm based on MRI measurement at the ME with the optimal threshold with the highest sensitivity and specificity as 18 mm2.
Cross-sectional area measurement of GT + ST at the ME correlated most closely to intra-operative diameter of a doubled hamstring autograft compared to measurements at the TJL or the TPS. As graft diameter < 8 mm is correlated with higher failure rates of ACL surgery, the ability to pre-operatively predict graft diameter is clinically useful.
Level of evidence
Level III, prognostic study.
KeywordsACL reconstruction Hamstring autograft MRI Graft size Anatomy Preoperative planning
Anterior cruciate ligament
Magnetic resonance imaging
Body mass index
Receiver operating characteristic
Area under the curve
Analysis of variance
Intraclass correlation coefficient (ICC)
All authors (1) have made substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data, (2)have been involved in drafting the manuscript or revising it critically for important intellectual content, (3) have given final approval of the version to be published, (4) agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
The authors received no financial support for the research, authorship, and/or publication of this article.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
The study was approved by the institutional review board (IRB) at our institution.
- 1.Agarwal S, de Sa D, Peterson DC, Parmar D, Simunovic N, Ogilvie R et al (2018) Can preoperative magnetic resonance Imaging predict intraoperative autograft size for anterior cruciate ligament reconstruction? A systematic review. J Knee Surg. https://doi.org/10.1055/s-0038-1666830 CrossRefPubMedGoogle Scholar
- 11.Mariscalco MW, Flanigan DC, Mitchell J, Pedroza AD, Jones MH, Andrish JT et al (2013) The influence of hamstring autograft size on patient-reported outcomes and risk of revision after anterior cruciate ligament reconstruction: a Multicenter Orthopaedic Outcomes Network (MOON) Cohort Study. Arthroscopy 29:1948–1953CrossRefGoogle Scholar