Danilo Bruni1, Laura Bragonzoni2, Michele Gagliardi3, Marco Bontempi4, Ibrahim Akkawi5, Giovanni Francesco Raspugli6, Francesco Iacono7, Silvio Patella8, Maurilio Marcacci9. 1. Biomechanics and Technological Innovation Laboratory, Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna University, Via Di Barbiano 1-10, 40136, Bologna, Italy. d.bruni@biomec.ior.it. 2. Dipartimento di Scienze Biomediche e Neuromotorie (DIBINEM), Univeristà di Bologna, Bologna, Italy. l.bragonzoni@biomec.ior.it. 3. Biomechanics and Technological Innovation Laboratory, Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna University, Via Di Barbiano 1-10, 40136, Bologna, Italy. michele.gagliardi4@studio.unibo.it. 4. Biomechanics and Technological Innovation Laboratory, Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna University, Via Di Barbiano 1-10, 40136, Bologna, Italy. m.bontempi@biomec.ior.it. 5. Biomechanics and Technological Innovation Laboratory, Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna University, Via Di Barbiano 1-10, 40136, Bologna, Italy. ibrahim.akkawi@studio.unibo.it. 6. Biomechanics and Technological Innovation Laboratory, Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna University, Via Di Barbiano 1-10, 40136, Bologna, Italy. giovi.ras@hotmail.it. 7. Biomechanics and Technological Innovation Laboratory, Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna University, Via Di Barbiano 1-10, 40136, Bologna, Italy. f.iacono@biomec.ior.it. 8. Biomechanics and Technological Innovation Laboratory, Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna University, Via Di Barbiano 1-10, 40136, Bologna, Italy. s.patella@biomec.ior.it. 9. Biomechanics and Technological Innovation Laboratory, Codivilla-Putti Research Center, Rizzoli Orthopaedic Institute, Bologna University, Via Di Barbiano 1-10, 40136, Bologna, Italy. m.marcacci@biomec.ior.it.
Abstract
PURPOSE: The main purpose of the present study was to determine long-term implant fixation of 15 unicompartmental knee arthroplasty (UKAs) with an all-poly tibial component using Roentgen stereophotogrammetric analysis (RSA) at a mean 10-year follow-up. The secondary purpose was to investigate whether the progressive loss of implant's fixation correlates with a reduction in Knee society score (KSS). METHODS: Fifteen non-consecutive patients with primary knee osteoarthritis received a UKA with an all-poly tibial component were assessed using KSS scores pre-operatively and post-operatively and RSA on day 2 after surgery, then at 3, 6, and 12 months and yearly thereafter. The mean last follow-up was 10 years. RESULTS: An increase in maximum total point motion (MTPM) values from 6 months to 1 year post-operatively was found respect to post-operative reference. Implants' displacement values were always <2 mm during the first 6 months, and then, two different trends were noticed in revised and non-revised implants. MTPM increase between 1 and 2 years of follow-up in non-revised UKAs was always <0.2 mm, whereas it was >0.2 mm in revised UKAs. A linear and negative correlation with statistical significance was found between MTPM and both clinical and functional KSS scores (p < 0.001). CONCLUSION: Also in a long-term follow-up evaluation, RSA is an effective tool to predict functional results after an all-poly UKA providing also a relevant predictive value at 1 year follow-up, and this can be very useful for both patients and surgeons. LEVEL OF EVIDENCE: Diagnostic studies, Level III.
PURPOSE: The main purpose of the present study was to determine long-term implant fixation of 15 unicompartmental knee arthroplasty (UKAs) with an all-poly tibial component using Roentgen stereophotogrammetric analysis (RSA) at a mean 10-year follow-up. The secondary purpose was to investigate whether the progressive loss of implant's fixation correlates with a reduction in Knee society score (KSS). METHODS: Fifteen non-consecutive patients with primary knee osteoarthritis received a UKA with an all-poly tibial component were assessed using KSS scores pre-operatively and post-operatively and RSA on day 2 after surgery, then at 3, 6, and 12 months and yearly thereafter. The mean last follow-up was 10 years. RESULTS: An increase in maximum total point motion (MTPM) values from 6 months to 1 year post-operatively was found respect to post-operative reference. Implants' displacement values were always <2 mm during the first 6 months, and then, two different trends were noticed in revised and non-revised implants. MTPM increase between 1 and 2 years of follow-up in non-revised UKAs was always <0.2 mm, whereas it was >0.2 mm in revised UKAs. A linear and negative correlation with statistical significance was found between MTPM and both clinical and functional KSS scores (p < 0.001). CONCLUSION: Also in a long-term follow-up evaluation, RSA is an effective tool to predict functional results after an all-poly UKA providing also a relevant predictive value at 1 year follow-up, and this can be very useful for both patients and surgeons. LEVEL OF EVIDENCE: Diagnostic studies, Level III.
Entities:
Keywords:
All-poly tibial component unicompartmental knee arthroplasty; Implant fixation; Maximum total point motion; Roentgen stereophotogrammetric analysis
Authors: K J Saleh; A Macaulay; D M Radosevich; C R Clark; G Engh; A Gross; S Haas; N A Johanson; K A Krackow; R Laskin; G Norman; J A Rand; L Saleh; G Scuderi; T Sculco; R Windsor Journal: Clin Orthop Relat Res Date: 2001-11 Impact factor: 4.176