The effect of sterilization and storage on the viscoelastic properties of human tendon allografts - Continued: Storage for 0 to 4 months.

The role of donor-derived tendons, also known as allografts, in anterior cruciate ligament replacement surgeries is steadily increasing. Before surgery, temporary storage and, in most cases, sterilization are essential. It is, thus, crucial to determine how these procedures alter the grafts' biomechanical properties. The purpose of this research was to analyze the effect of different sterilization methods (native, frozen, frozen + 21 kGy gamma irradiation, frozen + 21 kGy electron beam irradiation) and storage durations (0 to 4 months) on the deformation and creep of two tendon types (tibialis anterior, peroneus longus). 80 tibialis anterior and 83 peroneus longus tendons from 51 human cadavers were included. The samples were removed, placed in a radio-cryoprotectant solution, then slowly cooled, sterilized and stored at -80 °C. All groups were subject to 60 s static creep test with 250 N load. Deformation during the loading phase, creep during static loading, and the ratio of these two were evaluated. Deformation at the end of the loading phase and creep consistently exhibited significantly smaller values in the tibialis anterior compared to the peroneus longus type, as well as in electron beam-sterilized grafts as opposed to gamma beam-sterilized ones. Prolonged storage periods (within 0 to 4 months) resulted in a notable increase in these values, particularly in deformation. Based on the experimental data, the tibialis anterior tendon type and sterilization by gamma beam irradiation are better choices for anterior cruciate ligament reconstruction than the peroneus longus and sterilization by electron beam. Increased storage time affects negatively the evaluated mechanical properties.

Biomechanical testing of canine tibiae: Changes resulting from different tibial tuberosity advancement techniques - Pilot study.

The objective of the present pilot study was to determine the force required to break (a) intact canine tibiae, (b) tibiae following the osteotomy of the tibial tuberosity and (c) tibiae following Tibial Tuberosity Advancement- (TTA-) rapid surgery. Six pairs of tibiae of dogs between 15 and 35 kg body weight were used in a cadaver study. Three groups were created with four tibiae in each group; intact (Group 1), osteotomy of the tibial tuberosity and tibial crest (Group 2) and TTA-rapid (Group 3). The tibiae were put under static axial compressive load, applied until failure. The force required to break the tibiae was termed maximal force (F max). The mean of F max was 8193.25 ± 2082.84 N in Group 1, 6868.58 ± 1950.44 N in Group 2 and 7169.71 ± 4450.39 N in Group 3. The sample size was small for a statistical analysis but as a preliminary result, we have determined the force (F max) required to break canine tibiae. Furthermore, we hypothesise that osteotomies result in weakening of the tibial structure.

The effect of sterilization and storage on the viscoelastic properties of human tendon allografts.

Allografts have become increasingly preferred for anterior cruciate ligament replacement purposes. The risk of infections necessitates thorough sterilization procedures, and the allografts usually need to be stored prior to surgery. Classical mechanical tests have been performed with various types of tendons, however, tibialis anterior and peroneus longus tend to suffer the least biomechanical changes after irradiation. Only few results are available of the strain and creep behaviour of tendons, even though this information is necessary to provide suitable allografts. The aim of the present study is to analyze the effect of different tendon types (T-tibialis anterior, P-peroneus longus), sterilization methods (G-gamma irradiation of 21 kGy, E-electron beam irradiation of 21 kGy) and storage times (5 and 6 months) on the creep behavior, which is characterized by the strain at the end of the loading phase and creep deformation after static loading. Static creep tests were performed with 250 N load during 60 s. Deformation at the end of the loading phase of both tendons was significantly smaller after 5 months long storage than that after 6 months long storage. TE5 showed significantly less creep than group TE6, and TE6 significantly greater than PE6. The creep of TE5 was significantly lower than that of TG5. Based on the data, the peroneus longus sterilized by electron beam and stored deep frozen for 5 months is a better choice for anterior cruciate ligament reconstruction than tibialis anterior sterilized by gamma irradiation stored for 6 months.