Minimizing Unnecessary Harvesting of an Extremely Thin Gracilis Tendon During ACL Reconstruction by Referencing the Diameter of the Doubled Semitendinosus Tendon Alone

Background: The incidence of anterior cruciate ligament reconstruction (ACLR) graft failure is inversely related to the diameter of the ACLR graft. When the diameter of a 4-stranded hamstring tendon graft with a doubled semitendinosus and doubled gracilis tendon (ST×2 + G×2) configuration is <8 mm, the gracilis tendon is often thin.

Hypothesis: (1) The diameter of the doubled semitendinosus tendon (ST×2) alone would be able to predict the probability of a 4-stranded ACLR graft having a diameter of ≥8 mm, and (2) there would be a specific cutoff value for the ST×2 diameter such that the addition of a doubled gracilis tendon (G×2) will not result in a 4-stranded graft with a ≥8-mm diameter.

Study design: Cross-sectional study; Level of evidence, 3.

Methods: Included were patients who had undergone 4-stranded hamstring ACLR between 2008 and 2018. Patients were excluded if the diameter measurements of the tendons or ACLR graft were missing. A receiver operating characteristic (ROC) analysis was performed to assess the predictability of ST×2 on an ACLR graft with a diameter of ≥8 mm. The effect of including G×2 on the final graft size was reported.

Results: A total of 314 patients were included, and the mean diameters of ST×2 and G×2 were 6.5 ± 0.8 mm and 5.0 ± 0.7 mm, respectively. There was a moderate to strong correlation between the diameter of ST×2 and that of G×2 (men: r = 0.678; women: r = 0.654; P < .001 for both). An ST×2 with a diameter <6 mm predicted a 4-stranded ACLR graft of <8 mm (area under the ROC = 0.917; P < .001). When ST×2 was <6 mm, the addition of a G×2 did not result in the ACLR graft's having a diameter of ≥8 mm, regardless of patient sex or G×2 diameter.

Conclusion: When the diameter of the doubled semitendinosus was <6 mm, the addition of the doubled gracilis was unlikely to produce a 4-stranded ACLR graft with a diameter of ≥8 mm. Surgeons should consider alternative methods such as tripling or quadrupling the semitendinosus tendon to increase the size of the ACLR graft, rather than routinely harvesting the gracilis tendon.