<jats:sec><jats:title>Aims</jats:title><jats:p> The aims of this study were to evaluate the clinical and radiological outcomes of instrumented posterolateral fusion (PLF) performed in patients with rheumatoid arthritis (RA). </jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p> A total of 40 patients with RA and 134 patients without RA underwent instrumented PLF for spinal stenosis between January 2003 and December 2011. The two groups were matched for age, gender, bone mineral density, the history of smoking and diabetes, and number of fusion segments. The clinical outcomes measures included the visual analogue scale (VAS) and the Korean Oswestry Disability Index (KODI), scored before surgery, one year and two years after surgery. Radiological outcomes were evaluated for problems of fixation, nonunion, and adjacent segment disease (ASD). The mean follow-up was 36.4 months in the RA group and 39.1 months in the non-RA group. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p> Both groups had significant improvement in symptoms one year after surgery, while the RA group showed some deterioration of outcome scores owing to complications during the second year after surgery. Complications occurred at a higher rate in the group with RA (19 patients, 47.5%) than in those without RA (23 patients, 17.1%) (p < 0.001). A total of 15 patients in the RA group (37.5%) required revision surgery, mainly for implant failure and post-operative infection. </jats:p></jats:sec><jats:sec><jats:title>Discussion</jats:title><jats:p> Multimodal approaches should be considered when performing instrumented PLF in patients with RA to reduce the rate of complications, such as problems of fixation, post-operative infection and nonunion. Take home message: Specific strategies should be undertaken in order to optimise outcomes in patients with rheumatoid arthritis. Cite this article: Bone Joint J 2016;98-B:102–8. </jats:p></jats:sec>