Avoiding allograft length mismatch during anterior cruciate ligament reconstruction: patient height as an indicator of appropriate graft length.

Background: Given the increasing use of allografts in anterior cruciate ligament reconstruction, selection of appropriate-sized grafts may help individual surgeons as well as the efficiency of the overall system for graft distribution.

Hypothesis: Recipient patient height can predict the desired length for the tendinous portion of a patellar bone-tendon-bone allograft in anterior cruciate ligament reconstruction.

Study Design: Cohort study (Prognosis); Level of evidence, 2.

Methods: A series of 414 knees in 392 consecutive patients undergoing magnetic resonance imaging evaluation of knee pain were enrolled in the study. Data collected from magnetic resonance imaging included patella and patellar tendon length and intraarticular length of the anterior cruciate ligament. Patient age, height, weight, and gender were recorded. Linear regression analysis assessed the correlation between patient height and intraarticular length of the anterior cruciate ligament as well as patellar tendon length. The effect of variance in age, weight, and gender on anterior cruciate ligament intraarticular length was also measured.

Results: A strong positive correlation was found between intraarticular length of the anterior cruciate ligament and patient height (Pearson r = 0.73; P < .001). Anterior cruciate ligament length (y, in millimeters) as a function of height (x, in inches) can be expressed as y = 1.17x - 41.29. As a function of height (x, in centimeters), anterior cruciate ligament length (y, in millimeters) can be expressed as y = 0.4606x - 41.29. Age, gender, and weight did not significantly influence this relationship. A weak positive association was found between patient height and patellar tendon length.

Conclusion: Patient height can predict the desired length of the tendinous portion of a patellar bone-tendon-bone allograft. An addition of 10 mm is made to the predicted anterior cruciate ligament length to allow for aperture tibial and femoral fixation. Patellar bone-tendon-bone allografts can be requested based on recipient patient height as follows: 5 ft, 0 in to 5 ft, 6 in: tendinous length/total length, 45 mm/95 mm; 5 ft, 7 in to 6 ft, 1 in: 50 mm/100 mm; > 6 ft, 1 in: 55 mm/105 mm.