Detaillierte Beitrags-Information
| Beitragstitel | A SPECT/CT study of the in-vivo bone load of native patella after primary total knee prosthesis: which are the differences between native pain-free patella from overstuffed patellae needing secondary patellar resurfacing? |
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| Beitragscode | P056 |
| Autoren | |
| Präsentationsform | Poster |
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| Abstract |
Introduction The question to resurface the patella at the time of primary implantation of total knee arthroplasty (TKA) is still open. Aim of this study was to investigate which parameters correlate with the need for secondary patellar resurfacing after TKA. Methods 76 patients who underwent primary TKA (cruciate retaining or posterior stabilized) without patellar resurfacing because of primary osteoarthritis were retrospectively analyzed. Group N included 40 pain-free patients at 1- and 2-years postoperative controls. Group SR included 36 patients who developed patellar overstuffing that resolved after secondary patellar resurfacing. Both groups were comparable with regard to age, gender and knee side. All patients underwent pre- and postoperative standard knee x-rays, orthoradiograms and 1.5 years postoperative SPECT/CT. The following data were collected: pre- and postoperative leg axis and Caton-Dechamp index (CD-index), three-dimensional position of the TKA components and sizes of TKA components. The patellar bone load was evaluated on SPECT/CT images. According to a previously validated scheme, the patella was divided into 8 quadrants and the mean bone trace uptake (BTU) was calculated. All data were compared between groups with parametric and non-parametric tests and within groups with the Pearson’s correlation. Results Both groups showed corrected aligned TKA components and neutral postoperative leg axis (Group N: 1.03 varus ± 3.08; Group RS: 0.53 varus ± 0.96) which did not differ significantly. Despite pre- and postoperative CD-Index of both groups were within the normal range, group SR showed a significant higher postoperative CD-Index (Group N: 0.74 ± 0.16; Group RS: 0.86 ± 0.16). The patellar bone load was significant higher in three of four not articular quadrants in group SR (superolateral, superomedial and inferomedial). The Pearson’s correlation showed significant correlations between almost every patellar quadrant and the femoral size in group N and with the femoral and tibial size in group SR. Almost all quadrants of group SR correlated with the postoperative CD-Index (Not articular: inferolateral, superolateral, inferomedial; articular: inferomedial, inferolateral). Conclusions A significant higher bone load on the not articular half of the patella seems to be related to the need of secondary patellar resurfacing. The corrected alignment of the TKA components and postoperative leg axis could have limited the correlations with the SPECT/CT data. |