Die klinischen Ergebnisse des Schenkelhals-teilerhaltenden Kurzschaftes optimys nach einem und fünf Jahren im Vergleich zum Geradschaft twinSys

Total hip arthroplasty plays a major role in treating Arthrosis of the hip joint. There are numerous different approaches implant design which follow partly very different philosophies. The recent trend goes towards bone preserving short stems. The optimys short stems belongs to the femoral neck partly preserving short stems and orientates itself calcar-guided in the femoral bone. This study presents the short- and midterm clinical and radiological results of the optimys stem, one and five years after procedure. It also compares them to those of the already established straight stem twinSys. By comparing the results in Harris Hip Score, its sub scores and radiological results, this study wants to test if the short stem is an equivalent alternative to the straight stem. Furthermore, both groups are divided into subgroups by weight, body mass index and sex to test if there are advantages or disadvantages in either of those groups. Finally, the optimys is compared to results of other short stems on the market. Between 12/15/2010 and 08/31/2012 there were 559 primary implantations of either optimys or twinSys stem in the Vitos Orthopädische Klinik Kassel. This time window was the primary inclusion criterion for the study, only patients with a lack of compliance, impossibility to take part or if they were unable to understand the survey were excluded. After one and five years a standardised examination was carried out. This includes a questionnaire, a clinical examination and radiographs. Both stems show significant improvements after one and five years in Harris Hip Score and it’s sub scores. The optimys group increases from preoperative 43,18 to 86,53 after one year and 85,57 points after five years. The twinSys group improves from preoperative 40,33 to 78,44 after one year and 77,83 after five years. In the subgroups differences are significant as well. There were overall few complications in both groups. Two stems in each group had to be revised, one in each due to tumbling and periprothetic fracture and one in each because of nonintegration respectively aseptic loosening. In the twinSys group were two patients with perioperative fracture of the greater trochanter. The radiological results were promising as well. Just two patients in the optimys group showed subsidence of the stem and one with radiolucent lines, analogous to that there were 7 and 10 patients in the twinSys group. In comparison of both groups the optimys stem is significantly better after one and five years. In the sub scores only for „function“ after one and „function“ and „pain“ after five years. In the subgroups the optimys shows the biggest advantages in the „heavy“ and „obese“ patients. The smallest differences in both groups and their subgroups are in the sub score „mobility“. Since both stems are significantly better than preoperative we can assume they are equivalent. For the sub score Pain the optimys group is better, especially after five years and with lesser mean variation. This is probably because of the minimal invasive approach. The biggest differences are found in the sub score „function“. This might be because of the age-heterogeneity of both groups. But still the elderly patients in the optimys group show better results than in the twinSys group. In context to other short stems the optimys stem indicates to achieve similar results. The optimys short stem shows promising clinical results after one and five years and is better than the twinSys straight stem in total and the subgroups, especially in the sub score Function.