[Proximal interphalangeal (PIP) finger prosthesis - what have we learnt? Experiences over 10 years]. / Die PIP-Prothese - Was haben wir gelernt? Erfahrungen über 10 Jahre.

PURPOSE: 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. PATIENTS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

[Experience with the SRTM-PIP prosthesis as joint replacement: a retrospective overview with a follow-up of 2.4 years]. / Erfahrungen mit der SRTM-PIP-Prothese als Gelenkersatz: Eine retrospektive Studie mit einer Follow-up Periode von 2,4 Jahren.

PURPOSE: In the following article we present our results with a cemented titanium/polyethylene prosthesis. PATIENTS AND METHODS: The SR (TM)-PIP-prosthesis from the firm SBI (©) (formally Avanta (©)) was implanted in 39 patients in our clinic from 2001-2007. In all, we were able to follow-up in a retrospect clinical study 32 patients with 39 proximal interphalangeal joint prostheses. We examined the range of motion, the strength and looked for deformities. The patients had to fill in a questionnaire before examination about their pain and limitation in daily life. We also performed X-rays of the operated fingers. RESULTS: The postoperative range of motion was about 67°. The strength mean value was 24.7 kg. 4 patients needed surgical revisions, in one case due to loosening of the proximal part of the prosthesis. 2 patients also received a tenoarthrolysis because of extension deficits and one patient because of a swan-neck deformity. We noted 7 swan-neck deformities and in 7 cases we found implant loosening of the proximal part of the prothesis. The postoperative Quick-DASH score was about 32.2 and showed a good result. All participants reported a marked improvement in pain reduction. CONCLUSION: These positive results, the reduction of pain and the satisfaction of the patients advocate the use of this prosthesis for the proximal interphalangeal joint. The postoperative ROM is comparable to those of other prostheses. Concerning implant loosening and swan-neck deformity, these results still offer room for improvement. Critical judgement and further development of the prosthesis design, the operation technique and the instrumentation are required to further optimise the results.