Abstract
Aim of the study: The aim of our study is to provide a clinical and x-ray review of the Nexgen tantalum tibial plate prosthesis which have been implanted from 2004 to 2007 at our department, evaluating the short term osteointegration of the tantalum surface.
Instruments and methods: 17 Nexgen PTG have been implanted without sacrifice of the posterior ligament with tantalum tibial plateau. The tibial component is constituted by a tantalum and polythene monoblock: it is implanted a press-fit through two pegs. The evaluation has been conducted with a minimum of 12 months follow-up. We considered a total of 13 prosthesis implanted in 12. The average patients age is 59.9 years (SD of 3.5 years) and within the range 52–67 years. 77% of the prosthesis (10 prosthesis) has been implanted in female patients. In 100% of situations, the pathology at the origin of the implementation was the primary gonar-thritis. For the clinic evaluation we used the HSS scheme; for the X-ray evaluation we used the “Knee Society TKA Roentgenographic evaluation and scoring system”.
Results: clinical evaluation: the average HSS score we got at control (using the average score after 3months, 6months, 1 year and at present) is 91.7 (OS +/−7.6). The difference between the pre-surgery and at control score is about 27.6 scores. At check up every patient was free from pain with a complete operational recovery (11.19/12 scores). Nobody was using aids. The average pre-surgery articolarity was about 93 degrees, at check up we measured an average inflection extension of about 114.1 degrees. All the score differences between pre-surgery and post-surgery are statistically significant (P< =0.001). To conduct our study we used the statistical program SAS (v.8, Sas inc., North Carolina, USA). X-ray evaluation: we didn’t find any unstuck part, neither periprosthesis osteolysis nor prosthesis mobilisation. We didn’t find any periprosthesis radiolucency line bigger than 1mm and none of the previous ones had any complication at control. The absence of pain (subjective evaluation) and absence of radiolucency lines (an objective evaluation) represent two indirect parameters that we considered valid to evaluate the osteointegration of the implant.
Discussion: The improvement of the surgical technique, either technical either instrumental, associated with a lower degree of pain, let us suggest that the prosthesis implantation is indicated also in young patients with high operational demands, who need a fast and complete operational recovery. For the same reason, it’s important to guarantee a good osteointegration and a long survival of the implant, with maximum care of bond tissue, forecasting a subsequent review surgery. The features of tantalum seem to respond pretty well at these requirements, being quite similar in terms of structural characteristics to the spongious bond. The reliability of the material is assured by its use in the prosthesis surgery since a couple of years ago. The design of the prosthesis is convenient in order to save at most the bond tissue. The high friction coefficient against the bone and the physical and mechanical features of the tantalum tibial plateau guarantee a fast osteointegration of the prosthesis. Although it’s proven that the implant survival with or without cost of the posterior ligament is the same, the prosthesis without cost of the posterior ligament has been chosen because the maintenance of the patient ligament offers an intrinsic knee stability.
The optimal clinical and x-ray results, even if they are at short term, considered as indices of a good osteointe-gration, push us to believe that the use of the tantalum tibial plateau could be a good solution for any young patient with a gonarthrosis
The abstracts were prepared by incoming Professor Elena Brach del Prever. Correspondence should be addressed to IORS – President office, Dipartimento di Traumatologia, Ortopedia e Mediciana del Lavoro, Centro Traumatologico Ortopedico - Via Zuretti, 29 I-10135 Torino, Italy.
