The implant placement protocol with regard to primary (immediate) or secondary (delayed) implant placement was also reviewed, and there is limited evidence from Fenlon et al. that implant failure is significantly worse in immediately placed implants in comparison with a delayed approach in free vascularized grafts.

Implant success was shown to be lower than implant survival and was related to peri-implant bone loss, peri-implant hyperplasia and an inability to prosthetically restore the implants. This was most commonly related to combined bone and soft tissue grafts, specifically the soft tissue component. This soft tissue component provides a suboptimal soft tissue profile which could contribute to implant failure (as a result of peri-implantitis); however, well-designed long-term studies are needed to fully comprehend the effect on implant survival.

Implant complications were also noted specific to autogenous bone grafts related to peri-implant soft tissue overgrowth/hyperplasia and the possible need for soft tissue debulking/modification and mucosal/soft tissue graft around implants, which occurred commonly in combined bone and soft tissue grafts. These finding, however, are limited to low-level evidence in the form of a small number of retrospective observational studies.

Limitations

This systematic review has identified that the quality of evidence to inform clinical decision making regarding the use of implants in transported bone in this patient group is currently deficient. All studies included in the review were retrospective observational studies and in general reported on low patient and implant number and found to be at moderate to serious risk of bias.

A lack of consistency in definitions of the primary (implant related) outcome measures was observed. The outcome measures used in the studies varied and implant survival/success was not necessarily the primary outcome measure. Only 14 of the 20 studies reported the primary outcome measure to be implant survival/success whilst the remainder reported free flap survival, graft success and bone resorption of bone grafts as the primary outcome.