title: Allograft swelling after preparation during ACL reconstruction: do we need to upsize tunnels?
abstract: The purpose of this study was to determine whether the pull-through force of soft-tissue allografts increases over time after being hydrated with saline-soaked sponges. Eighteen aseptic soft-tissue, fresh-frozen anterior tibialis allograft specimens were thawed and sized using standard sizing guides. After sizing, initial pull-through force was measured using an Instron Model 5865 machine. Grafts were randomized to soak in saline sponges for 20, 40, or 60 min. After soaking, pull-through force was again assessed. Pre- and post-soaking pull-through forces were compared using a paired t test. The effect of time on pull-through force was evaluated using an ANOVA and Tukey post hoc test. Two allografts had initial pull-through forces outside the inclusion criteria and were excluded. The average pull-through force for the remaining 16 allografts pre-soaking was 43.0 N and post-soaking was 81.7 N, for an increase of 90 % (P < 0.001). Longer hydration time in the saline soaked sponges was not correlated with higher pull-through force (P = 0.724). Pull-through force post-hydration was not related to the allograft diameter (P = 0.641). Post-hydration, 33 % of grafts that had soaked for 20 min and 40 % of grafts that had soaked for 40 or 60 min required greater than 100 N pull-through force. Our data supports the hypothesis that soft-tissue allografts swell as a result of being stored in saline-soaked sponges, resulting in greater pull-through forces during graft passage. Surgeons should bear in mind that allografts swell when stored in saline-soaked gauze and should size their tunnels accordingly.
authors.affiliation: Department of Orthopaedics and Rehabilitation, University of Florida, 3450 Hull Road, Gainesville, FL, 32607, USA, taltbuch@ufl.edu.
authors.forename: Tristan
authors.initials: T
authors.lastname: Altbuch
authors.forename: Bryan P
authors.initials: BP
authors.lastname: Conrad
authors.forename: Eric
authors.initials: E
authors.lastname: Shields
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Farmer
mesh_terms: D064591:Allografts / Q000502:physiology*; D059549:Anterior Cruciate Ligament Reconstruction; D001696:Biomechanical Phenomena; D006801:Humans; D012965:Sodium Chloride; D013710:Tendons; D014867:Water
chemical_list: D014867:Water; D012965:Sodium Chloride