Union Outcomes in Medial and Central Column Tarsometatarsal Fusions: Single vs Multiple Joints.

BACKGROUND

Tarsometatarsal (TMT) joint arthrodesis is essential for managing surgical management of severe bunion deformities, complex midfoot trauma, and osteoarthritis. Various fixation methods and bone grafting types have been described, but the impact of the number of joints fused on union rates remains unclear. This study aimed to evaluate whether fusing multiple joints affects arthrodesis rates and to compare union outcomes among different fixation constructs and grafting techniques.

METHODS

We conducted a single-center retrospective cohort study of 582 TMT fusions, comparing single- vs multiple-joint fusions involving medial and central columns. The average follow-up was 15.5 months. Two fellowship-trained foot and ankle surgeons assessed radiographs and computed tomographic (CT) scans. Radiographic union was evaluated at 8 and 12 weeks as well as the specific fixation constructs and bone graft used across each joint.

RESULTS

Single-TMT-joint surgeries had a significantly greater proportion of fusions occurring by 12 weeks than the multiple-TMT-joint surgeries, 74.9% vs 67.0%, respectively, P = .0002. Ultimate union rates were similar for single-joint fusions (80.3%) and multiple-joint fusions (82.6%. Many nonunions were asymptomatic; the combined asymptomatic nonunion and union rate was 95.4%. The revision rate for all nonunions was 25.5%. Staple fixation was associated with higher nonunion rates in the second (46.15%) and third (37.5%) TMT joints, whereas screw fixation showed the highest nonunion at the first TMT joint (54.6%). The lowest nonunion rates were observed with combined interfragmentary screw fixation and plating across all joints. Diabetic patients and current smokers experienced higher complication and nonunion rates.

CONCLUSION

Although the radiographic nonunion rate (18.2%) exceeded prior reports, symptomatic nonunion was rare (4.6%). Multiple-TMT-joint surgeries required more time to confirm radiographic union than single joint surgeries. Among the modifiable factors, implant and graft choice were associated with differences in union rates.