Impact of Zweymüller Stem Modification on Clinical and Radiological Outcomes

Background. According to the analysis of large arthroplasty registers we have noted the increase in the use of non-cemented implants, because the latter shows the same results of implant survival as well as cemented implants. On the other hand, they can affect the quality of the bone around the implant in different ways. These components differ in shape, length, and surface properties. According to the analysis of the arthroplasty register of the Vreden National Medical Research Center of Traumatology and Orthopedics, a significant decrease of the Alloclassic femoral stem using can be noted. In parallel the use of its SL-PLUS MIA modification has increased significantly. Aims of the study: 1) to determine the influence of changes in the design of the Zweymüller-type femoral stem on midterm and long-term outcomes and its survival; 2) to identify the characteristics of adaptive remodeling of periprosthetic bone tissue around these femoral stems; 3) to determine risk factors for aseptic loosening of these femoral stems. Methods. 492 cases of hip arthroplasty using the Alloclassic and SL-PLUS MIA femoral stems were observed, with an average follow-up 78.6 months. The patients were divided into 2 groups according to the type of femoral stem. The assessment the hip articulation condition was carried out using the HHS and OHS. The intensity of the pain syndrome was assessed by VAS, and the level of patient’s satisfaction. The dynamic analysis of X-rays was also performed visually. Results. A significant improvement in clinical and functional results was observed according to the HHS and OHS in both groups of patients, regardless of the type of femoral stem. Analysis of X-rays over time showed differences in the behavior of these two femoral component models. The radiolucent lines around the femoral stem are absent in SL-PLUS MIA group, in Alloclassic stem group radiolucent lines are present even at a minimal period (12 months). We also found that a tight fit of Zweymüller femoral stems in the distal shaft is a risk factor for severe stress-shielding syndrome, especially in the funnel channels. But ceteris paribus, a distal tight fit of SL-PLUS MIA stems despite similar geometry of the distal part does not lead to such frequent manifestation of severe stress shielding. Conclusion. The change in Zweymüller stem design from Alloclassic to SL-PLUS MIA improved the nature of adaptive remodeling in the periprosthetic area of the femur. It may improve the long-term results of primary hip arthroplasty, but these differences require closer observation

Follow-Up After Hip and Knee Arthroplasty: a Review of the Literature and a Report on a Pilot Project at the Vreden National Medical Research Center of Traumatology and Orthopedics

Background. Today in our country, the follow-up of patients after arthroplasty is carried out in accordance with clinical guidelines, the wording of which is based on monographs from 2006, 2008, and 2014, in addition, clinical guidelines for follow-up do not take into account the results of treatment assessed by the patient himself. The purpose of this study was to examine existing systems and develop a proprietary follow-up system for patients after hip and knee arthroplasty. Results. A review of the literature revealed that follow-up of patients after arthroplasty is an unsolved problem, within which there is low coverage, reluctance or forgetfulness of the asymptomatic patient, the problem of accessibility of medical examinations, and an excessive financial burden on the health care system. Since 2022, fixed recommendations for follow-up after arthroplasty have been used in the clinical practice of our center in discharge epicrisis. Recommendations for the frequency of follow-up were formulated by experts based on a comprehensive review of the literature and their own experience. In the first three months, 221 hip and 235 knee evaluation questionnaires were collected through the proposed mechanism, with a progressive increase in the number of questionnaires based on weekly monitoring data. Conclusion. Unfortunately, the outpatient clinic system is not always able to provide qualitative monitoring of patients after arthroplasty due to various reasons, therefore, in our opinion, the implementation of the mechanism of remote monitoring of patients will allow detecting various complications at the stage of early diagnosis, which will contribute to prompt solution of these problems. The remote monitoring system is also an important source of scientific data