Factors Influencing Bone Union in Finger Distal Interphalangeal and Thumb Interphalangeal Joint Arthrodesis.

Background: Finger joint arthrodesis is a common operation which has many indications including acute trauma, post traumatic condition, osteoarthritis, and rheumatoid joint deformity. The objective of this study was to evaluate factors which may influence bone union in arthrodesis of the distal interphalangeal (DIP) joint of the fingers and interphalangeal (IP) joint of the thumb. Methods: A total of 310 arthrodesis (221 finger DIP and 89 thumb IP joint) were analysed retrospectively. We used variables related to the patient and to the operative technique in univariable and multivariable regression analysis. Outcome events were bone union within 90 days, established non-union, infection and re-operation. Results: Of the 310 operations 280 resulted in a favourable outcome while 30 resulted in bone non-union. In the univariable analysis the most important negative predictor variable for bone non-union was an operation done by other than hand surgery specialist (OR = 3.75, 95% CI = 1.727-8.140, p = 0.001), which also predicted the indication for re-operation (OR = 4.705, 95% CI = 1.563-14.163, p = 0.006). Because of insufficient event rate of bone non-union multivariable analysis was not possible for bone non-union. In the multivariable analysis rheumatoid arthritis had negative influence on bone union within 90 days (OR = 0.45, 95% CI = 0.219-0.925, p = 0.03) and none of the variables predicted infection. Conclusions: In our cohort finger DIP and thumb IP joint arthrodesis generally resulted in favourable outcome in terms of bony union regardless of the underlying medical condition or technical details of the surgical operation. Overall the results emphasize the importance of adequate surgical skill and practice even with a simple surgical operation.