Patient-Reported and Radiographic Outcomes After Revision Sacroiliac Joint Fusion.

BACKGROUND

Sacroiliac joint fusion (SIJF) has been established as an effective treatment for sacroiliac joint dysfunction. However, failure necessitating revision has been reported in up to 30% of cases. Little is known regarding outcomes of revision SIJF.

METHODS

We retrospectively reviewed all revision SIJF at a single academic center between 2017 and 2020. Revision surgery was performed using the principles of joint decortication, bone grafting, compression, and rigid internal fixation. Outcomes were assessed at 6 months and 1 year after surgery using the Oswestry Disability Index (ODI), Numeric Pain Rating Scale (NPRS), and Single Assessment Numeric Evaluation (SANE) scale. Fusion was assessed using computed tomography at 12 months postoperatively.

RESULTS

Eighteen revision SIJFs in 13 patients were included. The mean age was 55.8 years (range 35-75). Mean body mass index was 27.9 (range 21.7-36.7). Sixty-two percent of the patients were women. The indications for revision were pseudarthrosis without fixation failure in 14 cases (77.8%), hardware failure (loosening) in 3 cases (16.7%), and continued pain after partial fusion in 1 case (5.6%). ODI and NPRS scores demonstrated significant statistical and clinical improvements at all timepoints. Mean (SD) ODI scores improved from 53.8 (19.9) preoperative to 37.5 (19.8) at 6 months and 32.9 (21.7) at 12 months. Improvement in ODI was found in 15 joints (83.3%), and the minimal clinically important difference (MCID) was achieved in 12 joints (66.7%). Mean (SD) NPRS scores improved from 6.5 (1.4) preoperative to 3.2 (2.8) at 6 months and 3.4 (2.6) at 12 months. Improvement in NPRS was also identified in 17 joints (94.4%), and 10 joints (55.6%) achieved MCID for NPRS. Mean (SD) SANE score was 72.0% (30.8) at 6 months and 70.0% (33.8) at 12 months. There were no radiographic lucencies, implant subsidence, or implant fractures at final follow-up. We identified an 88.9% fusion rate with definitive bridging bone across the sacroiliac joint.

CONCLUSION

Utilizing a principles-based technique of joint decortication, compression, and rigid internal fixation, revision SIJF showed an improvement in patient-reported outcomes as well as high rate of fusion at 12 months. The most common indications for revision SIJF are symptomatic pseudarthrosis and implant loosening. This is the largest series of revision SIJF to date.