Background Rheumatoid arthritis (RA) patients are reported to be often affected by fracture-healing complications not only as a result of osteoporosis. The inflammatory disease itself and anti-rheumatic drugs (e.g. glucocorticoids, GC) are supposed to interfere with the healing process. However, current literature studies reporting the number of afflicted patients and/or indicating the negative impact of comorbidities or even standard medications on the fracture healing are scarce.

Objectives The aim of this study is to evaluate the clinical relevance of especially RA and GC treatment as well as other comorbidities as potential risk factors for fracture healing disorders in a single-center retrospective study at the Center of Musculoskeletal Surgery (Charité University Hospital Berlin). According to our preliminary data, we now included an enhanced patient cohort as well as a control group that fulfills the required criteria.

Methods Based on the database of the Center for Musculoskeletal Surgery at Charité University Hospital Berlin patients were selected who underwent surgery at this institution to treat fracture healing complications in 2012. Exclusion criteria were age below 18 years at initial fracture, open fracture, and metastases close to fracture location. Our data were compared with a control group matched for age and type of fracture at the ratio of two. Descriptive and explorative data analysis as well as statistical evaluation of logistic regression were performed. The latter method starts with a univariable regression (Omnibus-Test p≤0.15) to identify co-variables for further investigations. The identified co-variables were subsequently tested with multivariable regression using regression elimination to determine interfering factors.

Results 266 patients were included in the study whereas 79 cases and 178 controls were compared. The mean age was 52.6 years and 140 females and 126 males could be identified. The descriptive analysis showed higher frequencies of GC (6.3% vs. 1.6%) and NASAID (7.6% vs. 2.7%) administration in patients with fracture healing disorders. Additionaly, patients suffering from rheumatoid arthritis (6.3% vs. 0.5%), arterial hypertonia (43.0% vs. 33.5%) and smokers (37.8% vs. 28.1%) more frequently exhibited delayed fracture healing. Statistical analysis using logistic regression showed high significance for rheumatoid arthritis patients (p=0.028, odds ratio 12.1) and a trend for smokers (p=0.075, odds ratio 1.7) as interfering factors favoring bone healing disorders.

Conclusions Taken together, the results we have obtained so far support the hypothesis that especially RA has a negative impact on the outcome of fracture healing as well as smoking. To our knowledge, this is the first retrospective study focusing on risk factors for bone healing complications in Germany. Furthermore, the results confirm observations known from in vitro and in vivo studies in humans.

Acknowledgements We thank Prof. Schlattmann for his support.

Disclosure of Interest None declared