[Proximal interphalangeal (PIP) finger prosthesis - what have we learnt? Experiences over 10 years]

In the following article we evaluate the clinical and radiological results after PIP joint replacement to answer the question if the outcome improved over the last years.

In a retrospective clinical study 53 patients with 66 PIP joint implants (SBI-Avanta, Small Bone Innovations, Inc.) were assessed on the basis of clinical and radiological parameters. We examined the patients' range of motion, their grip strength, the rate of radiological loosening, the development of pain and the patients' satisfaction. 2 groups were included in the study. Patients operated from 2001 to 2007 (group A) were compared with patients operated from 2008 to 2011 (group B). To facilitate a standardized examination, we developed a score providing a comprehensive representation of the outcome after PIP joint replacement.

Group B showed significant improvement in the rate of loosening of the prosthesis (44-4%) in the last follow-up examination. Further improvement was demonstrated in pain reduction, range of motion (77°/67°), the patients' satisfaction and development of swan neck deformity (11%/18%). There was no significant improvement in the patients' grip strength and the rate of revision surgery.

Overall, the results after PIP joint replacement are very good. All patients reported a marked improvement in pain reduction. In group B a significant reduction in the rate of loosening of the prosthesis was shown. Moreover, the rate of swan neck deformity, the range of motion, the reduction of pain and the patient's satisfaction improved over the last years. The application of a new PIP-joint-score for a standardized evaluation of the outcome indicated a good correlation with patient satisfaction over time. The experience of the past years enabled improvements in PIP joint replacement. We consider cementing the prosthesis, a large contact area between the prosthesis and the bone and an emphasis on easy intraoperative flexion/extension as factors which can improve the results after PIP joint replacement. However, some problems could not been solved to date. In this respect, prospective clinical and biomechanical studies are necessary.