The results of this study confirm a small ongoing failure rate for the Fast-fix 360™ meniscal repair system, despite the device modifications undertaken by the manufacturer since its introduction. While the deployment failure rate of 4.72% in this series is lower than 11.6% reported by Bellemens et al  with the original Fast-fix™ design, direct comparisons are not possible. This deployment failure has secondary consequences of both increased costs and possible patient harm.
A number of failure modes were recognized. Of the twenty cases, six were due to failure of one or both anchors to hold in the meniscus (see Table 6). There are a number of possible explanations for this. One possible reason for failure may be that the potentially poor quality of the meniscus/capsule on occasion prevents the anchor from achieving an appropriate mechanical lock on the capsule. This is more likely in older patients where the quality of the meniscus may be less than ideal. An alternative explanation may be design issues, as the new Fast-fix 360™ design has a reduced needle gauge on the delivery device and smaller suture anchors when compared to previous Fast-fix devices to reduce the secondary iatrogenic meniscal damage from device deployment. The smaller suture anchors may have less capsular mechanical fixation abilities compared to previous larger anchors. In the study by Barber et al comparing a number of different device failure mechanisms in a cadaver model pull out study they noted the Fast-Fix 360™ failed mostly by the pulling out of the peripheral meniscus. They reasoned that the smaller size of the Fast-Fix 360™ anchor to other devices may explain this failure mechanism.
In this study there was a gender difference in failure rate with a higher failure rate in males, however the cause of this is unclear. This differs to the results of Zimmerer . In their long term outcome study using the Fast-Fix ™ system they noted a statistically higher failure rate for women than men (40 failures in women 23 failures in men) where failure was defined as a new operation on the same meniscus. The authors were unable to explain their observed gender difference.
During the study failure of one or both anchors to exit the device was the most common cause of deployment failure. This may be related to the design of the anchor mechanism. A smaller anchor may allow for more error in loading when the anchor is pushed down the needle by the deployment mechanism. The smaller anchor may not capture in the meniscus as well and tend to remain in the needle of the device if it does not engage with the meniscus, again this is supported by the high association of age over 40 and deployment failure. In 6 cases deployment failure were failures that could be attributed to the device alone. In one case the first anchor, “Anchor 1”, exited the delivery device without deployment of the trigger. In three cases both Anchor 1 and the second anchor, “Anchor 2”, deployed simultaneously, and in two cases the suture itself failed. While the Fast-fix 360™ meniscal repair system is machine loaded and the one-way sliding knot is tied mechanically, it is possible that an error may occur during packaging of the device or tying the suture.
Only six of the twenty failures were at the Anchor 1 site, with fourteen failures occurring after Anchor 1 has been deployed (see Table 5). When deployment failure of Anchor 1 occurs, iatrogenic meniscal damage risk is low as a new device can be placed into the prior needle hole if present. However, if the Anchor 1 has been placed into the meniscus and a deployment failure occurs, the risk of iatrogenic meniscal damage is much greater. Removal of the partially deployed device without iatrogenic meniscal damage can be challenging.
The modes of failure of this study are similar to that of Bellemans et al , analysing the failure rate of the original Fast-fix device, and each account for a similar percentage of the total failures. They reported that 17 of the 22 reported instances of failure being due to intraoperative failure, with the remainder being due to the device itself malfunctioning. This is comparable to the results of this study, where 15 of the 20 failure were intraoperative and 5 where device malfunctions.
The report by Barber et al  examines the biomechanical performance of a number of all inside meniscal repair devices in a load to failure test in a cadaver meniscus. The current study examines the failure mechanism at the time of insertion of the device. These reports are complimentary in defining the failure mechanisms of all inside meniscal repair techniques. This report may be useful to provide a benchmark for which other devices may be compared to.
There is a significant cost associated with these devices. I n Australia all meniscal suture anchor devices cost $442 per use as set by the Australian Federal Department of Health Prosthesis List. A device deployment failure occurred in 17% of cases, an extra cost of $75 per case and $8840 in this series of patients. Health care providers should be aware of the added costs associated with the use of these devices.
The main disadvantage of this study is that a direct comparison with the original Fast-fix is not possible as it is no longer manufactured. The study was performed by a single experienced surgeon in a dedicated arthroscopy theatre, and the results may not be reproduced in a general setting. Although this study encompasses a large series of cases, with a large quantity of devices being uses, the study is a disadvantaged by the lack of a control group.
The mechanism of injury was not recorded as part of this study. The mechanism of injury may reflect the quality of the meniscus and its ability to hold the meniscal suture device. Zimmerer  found a correlation between soccer and indoor sports as a mechanism of injury and subsequent long term failure of meniscal repair with the Fast-fix system.