Iliotibial band autograft: what size is the graft? A mathematical and cadaveric model : ITB single and double strand size.

BACKGROUND: The iliotibial band (ITB) is used in anterior cruciate ligament (ACL) reconstruction in skeletally immature patients as well as several other orthopedic reconstructions. The purpose of this study is to determine the size of the ITB as an autograft option in ACL reconstruction surgery or other orthopedic soft tissue reconstructions. METHODS: Five adult cadavers resulting in nine ITB were used. Thickness and width of the ITB were determined. Using ITB width of 15-60 mm, single and doubled graft sizes were determined using standard surgical graft size technique. Geometric calculations based on average graft thickness were used to mathematically confirm the graft size of the ITB. RESULTS: The ITB is less than 1 mm in thickness in males and females. Cadaveric measurements were less than 1 mm larger than mathematical measurements, in majority of measurements. ITB autograft can be harvested to a maximum 9 mm single-stranded graft or > 12 mm doubled graft. A minimum of 50 mm of ITB width is required to make a 8 mm graft. CONCLUSIONS: ITB is a versatile graft that can be used for a graft size up to 9 mm single strand and over 12 mm double strand. A minimum of 50 mm width of ITB is required to obtain a 8 mm-diameter autograft. To ensure appropriate graft size, surgeons should consider harvesting the maximum amount of ITB when performing ACL reconstructions in skeletally immature patients. CLINICAL RELEVANCE: Surgeons have a quick reference for the width of ITB they should harvest based on the size of graft they require for a successful surgery.

Hamstring Autograft Too Small: How Much Allograft Do You Need to Supplement to a Desired Hybrid Graft Size?

PURPOSE: To determine a simple rule for choosing supplemental allograft size for hybrid anterior cruciate ligament reconstruction using mathematical and cadaveric models. METHODS: Mathematical and cadaveric models were used to determine the rule. The mathematical model required application of the geometric Pythagorean theorem to add areas of circles. Cadaveric semitendinosus and gracilis tendons were combined in multiple quadrupled hamstring size combinations and then sized using standard surgical techniques to confirm the mathematical model. RESULTS: Geometric measurement, not simple addition, of graft diameters was required to determine the final graft size. Direct comparison of cadaveric and mathematical models showed close relations. If a final graft size of 7 mm is desired, an added diameter of all grafts of approximately 9.5 mm is needed. If a final graft size of 8 mm is desired, an added diameter of all grafts of approximately 11 mm is needed. If a final graft size of 9 mm is desired, an added diameter of all grafts of approximately 12.5 mm is needed. If a final graft size of 10 mm is desired, an added graft diameter of approximately 14 mm is needed. Cadaveric hamstring measurements were similar to the mathematical model. CONCLUSIONS: By use of mathematical and cadaveric models, simple rules for determining the additional size of allograft diameter needed to supplement undersized hamstring autograft were created. CLINICAL RELEVANCE: With the increasing availability of allograft types and sizes, surgeons currently have no guidelines on the size of allograft that is required to supplement an undersized hamstring autograft. Simple rules were created for determining the amount of allograft supplementation required for undersized hamstrings and are easily applied to clinical situations.