2015 ISAKOS Biennial Congress ePoster #1419

Roentgen Stereophotogrammetric Analysis: An Effective Tool to Predict Implant Survival After an All-Poly Unicompartmental Knee Replacement. A 10 Years Follow-Up Study

Danilo Bruni, MD, Bologna ITALY
Laura Bragonzoni, PhD, Bologna ITALY
Michele Gagliardi, MD, Bologna ITALY
Marco Bontempi, Bologna ITALY
Ibrahim Akkawi, MD, Bologna ITALY
Tedi Marko, MD, Bologna ITALY
Silvio Patella, MD, PhD, Bari ITALY
Maurilio Marcacci, MD, Rozzano, Miilano ITALY

Biomechanics and Tecnologic Innovation Laboratory- Rizzoli Orthopaedic Institute, Bologna, Bologna, ITALY

FDA Status Not Applicable

Summary: Roentgen Stereophotogrammetric Analysis (RSA) represents nowadays an excellent solution for high-accuracy fixation measurement of UKAs. Also in a long term follow up evaluation, RSA is an effective tool to predict functional results after an all-poly UKA.

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Abstract:

Introduction

Roentgen Stereophotogrammetric Analysis (RSA) represents nowadays an excellent solution for high-accuracy fixation measurement of UKAs. To date, to the best of our knowledge, no previous study has investigated long-term micromotions of a UKA using RSA.

Objective

The main purpose of the present study is to determine long-term implant fixation of 15 UKAs with all-poly tibial component using RSA at a mean 10-years follow-up. The secondary purpose was to investigate whether the progressive loss of implant’s fixation correlates with a reduction of KSS scores.

Methods

Fifteen non-consecutive patients with primary knee osteoarthritis received a UKA with an all-poly tibial component between January 1995 and April 2003 in the Authors’ institution. Pre and post-operative KSS scores were recorded. RSA evaluation was performed on day 2 after surgery, than at 3, 6, and 12 months and yearly thereafter. The patients were evaluated with a mean follow-up of 10 years.

Results

An increase of MTPM (Maximum Total Point Motion) values from 6 months to 1 year post-operatively was found respect to post-operative reference. Implants’ displacement values were always less than 2 mm during the first 6 months, than two different trends were noticed in revised and non-revised implants. A linear and inverse correlation with statistical significance was found between MTPM and both clinical and functional KSS scores .

Conclusions

Also in a long term follow up evaluation, RSA is an effective tool to predict functional results after an all-poly UKA.