Bioabsorbable screws in first MTP fusion: two years, nothing to report

Design

Prospective pilot randomised controlled trial, 1:1, two hospitals, two-year follow-up

Population

30 patients undergoing first metatarsophalangeal joint arthrodesis by cup-and-cone technique

Primary outcome

AOFAS and FA-VAS scores, union rate and complications to 24 months

Effect

AOFAS 89.1 titanium vs 90.0 bioabsorbable (P = 0.23); union 90% overall; no implant-related complications or hardware removal in either arm

Thirty patients were randomised 1:1 to bioabsorbable or titanium cannulated lag screws for first metatarsophalangeal joint arthrodesis, performed with a cup-and-cone technique at two Finnish hospitals, with full weight-bearing in an orthopaedic shoe from six weeks. Outcomes were assessed at 3, 6, 12 and 24 months.

At two years the groups were indistinguishable. Mean AOFAS was 89.1 with titanium and 90.0 with bioabsorbable screws (P = 0.23); FA-VAS totals were 1948 and 1914 (P = 0.655). Union was 90% overall, with nonunion in one titanium and two bioabsorbable patients, all requiring revision. There were no implant-related complications and no hardware removal operations in either arm, and screw degradation produced no adverse clinical or radiographic reaction.

The practical question bioabsorbable fixation has always faced is not whether it holds but whether it misbehaves as it dissolves - sterile inflammation, osteolysis, cyst formation. Over two years in 15 patients, it did not. That is a small denominator for a rare complication, and the authors frame this as feasibility supporting a larger trial rather than as a result. But for a surgeon who fuses first MTP joints in patients where a prominent screw head is likely to need removal, this is the first randomised signal that the alternative is not worse.

• Frame this as feasibility, not equivalence - 30 patients cannot establish either
• Union rate was 90% overall, which is the figure to quote at consent whichever screw you use
• All three nonunions needed revision; discuss that outcome specifically
• The case for bioabsorbable rests on avoiding hardware removal, which neither arm needed here
• Cost and availability, not the trial, will decide this in most Indian units

Why it matters

The objection to bioabsorbable fixation has always been what happens while it degrades, and here nothing did.

Don't overread it

A pilot trial of 30 patients - 'no difference' means undetectable, not absent.

The statistics, in plain English

With 15 patients per arm, a P value of 0.23 or 0.655 tells you almost nothing beyond the absence of a large difference - this trial could not have detected a moderate one. The reported bioabsorbable AOFAS of 90.0 with a standard deviation of 0.0 means every patient in that arm scored identically, which is a ceiling effect in the instrument rather than a finding about the screws. The more informative number is the union rate: three nonunions in 30 patients, two of them bioabsorbable, is exactly the kind of imbalance a pilot cannot interpret and a larger trial exists to resolve.

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