Peroneus Longus Split Versus Semitendinosus Tendon Autograft Size: A Cross-sectional Study

Abstract

Background: The anterior half of the peroneus longus tendon (AHPLT) has been reported to be a suitable autograft for ligament reconstruction with low donor-site morbidity. However, clinical data on graft size are limited. Purpose: To determine (1) if there is any difference in size between the AHPLT and semitendinosus tendon (ST) and (2) whether anthropometric measurements can predict autograft size. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 128 consecutive patients scheduled for knee ligament reconstruction were prospectively enrolled. Patients were treated with AHPLT (50%) or ST (50%). Data included anthropometric measurements and intraoperatively recorded graft size. A Student t test was used to determine differences between the groups. Bivariate correlation coefficients and multivariate regression analyses were calculated to identify relationships between graft size and anthropometric measurements. Results: The AHPLT and ST groups were equally distributed according to age, sex, height, weight, and body mass index (BMI). The quadrupled graft length for the AHPLT was 7.3 ± 0.6 cm as compared with 7.5 ± 0.7 cm for the ST ( P < .05). The quadrupled graft diameter was 7.7 ± 0.8 mm for the AHPLT and 8.0 ± 0.7 mm for the ST ( P < .05). Height had a moderate ( r = 0.57) to high ( r = 0.68) correlation with AHPLT and ST length, respectively ( P < .01). Weight had a moderate correlation ( r = 0.43) with AHPLT diameter ( P < .01) but only a weak correlation ( r = 0.19) with ST diameter ( P > .05). A significant interaction effect of BMI and thigh circumference on ST graft diameter was found, which showed that the effect of thigh circumference on ST graft diameter decreased significantly as BMI increased ( P < .05). This moderating effect of BMI could not be observed for the coefficient of shank circumference on AHPLT graft diameter ( P > .05). Conclusion: (1) The peroneus longus split tendon provides a reliable autograft size for knee ligament reconstructions. It was prone to be slightly shorter and thinner than the ST. (2) Patient height was the strongest predictor for AHPLT and ST graft length. However, predicting graft diameter based on thigh or shank circumference was more challenging, with higher BMIs affecting the ability to predict ST more than AHPLT.