Nitinol Compression Staples in Foot Orthopaedic Surgery: A Systematic Review

Nitinol compression staples have been increasingly used in foot and ankle orthopaedic surgery because of simple implantation, reproducibility, and favorable biomechanical features. Compared with traditional implants (i.e., plates and screws), nitinol staple use in foot and ankle orthopaedics has not been extensively described. This systematic review aims to describe the current clinical outcomes of nitinol staple use in forefoot and midfoot surgery.

A search was conducted using PubMed, Web of Science, and Embase. All studies that included clinical outcomes of nitinol in foot surgery were evaluated for their demographics, outcome scores, or complication rates. Biomechanical studies and studies investigating nitinol nails in the hindfoot were excluded. Two reviewers screened titles, abstracts, and full texts.

Of the 198 total articles from the search, 9 articles met the inclusion criteria. Of the 9 articles, 4 articles investigated outcomes of nitinol in the forefoot, 3 articles in the midfoot, 1 article in the forefoot and midfoot, and 1 article in the midfoot and hindfoot. This systematic review included articles that were retrospective in nature and thus subject to selection bias. The mean follow-up ranged from 6 to 35.9 months. The included studies demonstrated significantly improved postoperative visual analog scale pain score (P < .001), Ankle Osteoarthritis Scale scores (P < .001), and Foot and Ankle Ability Measure activities of daily living scores (P < .001). Of the 6 studies that report union for patients receiving purely nitinol staple constructs or nitinol staples in combination with another construct, the overall fusion rate was 94.6% and the overall complication rate was 11.25%.

This systematic review demonstrates that nitinol staples in foot surgery, whether alone or in combination with another construct, can achieve an acceptable fusion rate. However, currently we found highly limited clinical study data directly comparing nitinol staples to traditional implants. The current literature is heterogenous in its discussion of nitinol staple configurations and designs.

Level IV, Systematic Review.