Can pre-operative measures predict quadruple hamstring graft diameter?

The use of autologous grafts such as the quadrupled semitendinosus and gracilis tendon is very common in anterior cruciate ligament (ACL) reconstruction. The diameter of such grafts can be variable and thus unpredictable prior to surgery. In this study, we hypothesized that parameters such as gender, height, age, and body mass index (BMI) can be used pre-operatively to reveal the true graft diameter. All hamstring ACL reconstructions from 1994 to 2002 were reviewed. 536 cases (302 females, 234 males) met the inclusion criteria. Quadruple hamstring constructs and femoral tunnel diameters were measured using 1mm increment graft sizers. Pre-operative measures of height, weight, body mass index, gender, and age were obtained. Multiple regression analysis was used to build a predictive model of the quadruple hamstring graft diameter. The results of the study demonstrated that males had significantly larger grafts than females (8.1+/-0.8 vs. 7.5+/-0.6mm). Multiple regression analysis on the entire group showed that pre-operative height (p<0.0002) and gender (p<0.0047), but not age (p<0.06) or weight (p<0.019) were significant predictors of graft diameter. Height (p<0.0001) was a specific predictor solely in men. In females, none of the pre-operative measures were predictive of graft diameters. Patient height and gender can be used as pre-operative indicators of in vivo quadrupled hamstring graft diameter. Regardless of other variables, 42% of females will have tunnel diameters of 7mm or less. An alternative graft choice should be discussed pre-operatively if graft sizes may be of concern for the tall and large female patients.