Bioresorbable Screws for First MTP Fusion — Promising, but Evidence Is Limited

Bioresorbable screws may be a feasible alternative to titanium screws for first metatarsophalangeal joint arthrodesis, but the new trial is too small to establish equivalence or superiority. This distinction matters: failure to detect a statistically significant difference in a pilot sample does not mean that the two methods produce identical outcomes.

Polish version · For Doctors and Physiotherapists

Why is this study interesting?

First MTP joint fusion is used for advanced hallux rigidus, severe deformity and selected revision procedures. Fixation has to maintain alignment until union occurs. A bioresorbable implant could theoretically avoid permanent metal hardware, but it still has to provide adequate stability and degrade without clinically important tissue reactions.

Question and methodology

Partio and colleagues conducted a prospective pilot randomised trial in two Finnish hospitals. Thirty patients were allocated 1:1 to fixation with cannulated bioresorbable screws or titanium screws. Joint surfaces were prepared using a cup-and-cone technique, and full weight bearing in a postoperative shoe was allowed after six weeks.

Union, complications and functional outcomes were assessed at 3, 6, 12 and 24 months. The trial was registered as NCT03133039.

Results

• Both groups showed substantial functional improvement, with no demonstrated between-group difference.
• At 24 months, mean AOFAS scores were 89.1 in the titanium group and 90.0 in the bioresorbable group (p = 0.23).
• The overall union rate was 90%.
• Nonunion occurred in one patient with titanium screws and two patients with bioresorbable screws; all three required revision surgery.
• No clinical or radiographic adverse events were attributed to degradation of the bioresorbable screws.
• No patient in either group underwent hardware removal.

Clinical interpretation for an orthopaedic surgeon

The main value of this study is as an early signal of feasibility and safety. At two years there were no reported reactions related to implant degradation, and functional outcomes were good in both groups. That is sufficient to justify a larger study, particularly if bioresorbable fixation is expected to reduce problems associated with retained metalwork.

It does not, however, demonstrate a practical advantage. Hardware was not removed in the titanium group either, so the proposed benefit of avoiding a later removal procedure was not shown here. Three nonunions among 30 participants are also far too few events for a reliable comparison of uncommon complications.

Key limitations

• This was a pilot study with only 30 patients.
• It was not designed as an equivalence trial with a prespecified equivalence margin.
• The small sample provides very limited power for nonunion, implant reactions and reoperations.
• The AOFAS score has methodological limitations, and the bioresorbable group was reported with a mean of 90.0 and a standard deviation of 0.0 at 24 months, making the score distribution difficult to interpret.
• Two years of follow-up does not answer every question about late material degradation.

What might this change in practice — and what does it not prove?

For now, these results support further adequately powered trials of bioresorbable screws. They do not justify treating the technique as standard, safer, or equivalent to titanium fixation. Choice of fixation should still account for construct biomechanics, bone quality, deformity, likelihood of union and the surgeon’s experience.

Source

Partio N, Mattila V, Waris V, Mäenpää H. Bioabsorbable vs. titanium screws in first metatarsophalangeal joint arthrodesis: a pilot randomized controlled trial with 2-year follow-up. Archives of Orthopaedic and Trauma Surgery. Published 9 September 2026;146(1):329. DOI: 10.1007/s00402-026-06501-2. PMID: 42714616.

Content prepared by: Tomasz Poboży - orthopaedic surgeon.