TY - JOUR A1 - Rak, Dominik A1 - Klann, Lukas A1 - Heinz, Tizian A1 - Anderson, Philip A1 - Stratos, Ioannis A1 - Nedopil, Alexander J. A1 - Rudert, Maximilian T1 - Influence of mechanical alignment on functional knee phenotypes and clinical outcomes in primary TKA: a 1-year prospective analysis JF - Journal of Personalized Medicine N2 - In total knee arthroplasty (TKA), functional knee phenotypes are of interest regarding surgical alignment strategies. Functional knee phenotypes were introduced in 2019 and consist of limb, femoral, and tibial phenotypes. The hypothesis of this study was that mechanically aligned (MA) TKA changes preoperative functional phenotypes, which decreases the 1-year Forgotten Joint (FJS) and Oxford Knee Score (OKS) and increases the 1-year WOMAC. All patients included in this study had end-stage osteoarthritis and were treated with a primary MA TKA, which was supervised by four academic knee arthroplasty specialists. To determine the limb, femoral, and tibial phenotype, a long-leg radiograph (LLR) was imaged preoperatively and two to three days after TKA. FJS, OKS, and WOMAC were obtained 1 year after TKA. Patients were categorized using the change in functional limb, femoral, and tibial phenotype measured on LLR, and the scores were compared between the different categories. A complete dataset of preoperative and postoperative scores and radiographic images could be obtained for 59 patients. 42% of these patients had a change of limb phenotype, 41% a change of femoral phenotype, and 24% a change of tibial phenotype of more than ±1 relative to the preoperative phenotype. Patients with more than ±1 change of limb phenotype had significantly lower median FJS (27 points) and OKS (31 points) and higher WOMAC scores (30 points) relative to the 59-, 41-, and 4-point scores of those with a 0 ± 1 change (p < 0.0001 to 0.0048). Patients with a more than ±1 change of femoral phenotype had significantly lower median FJS (28 points) and OKS (32 points) and higher WOMAC scores (24 points) relative to the 69-, 40-, and 8-point scores of those with a 0 ± 1 change (p < 0.0001). A change in tibial phenotype had no effect on the FJS, OKS, and WOMAC scores. Surgeons performing MA TKA could consider limiting coronal alignment corrections of the limb and femoral joint line to within one phenotype to reduce the risk of low patient-reported satisfaction and function at 1-year. KW - knee arthroplasty KW - mechanical alignment KW - clinical outcome KW - phenotype KW - level of evidence III KW - prospective study Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-313646 SN - 2075-4426 VL - 13 IS - 5 ER - TY - THES A1 - Dörries, Susanne T1 - Analyse der Gründe für Revisionsoperationen bei einliegender Knieprothese T1 - Analysis of the reasons for revision surgery with inserted knee arthroplasty N2 - Die Knieendoprothetik verzeichnet in den letzten Jahren steigende Zahlen, was wiederum steigende Zahlen an Revisionen zur Folge hat. Diese Studie hat die Gründe für Revisionen ermittelt. Hierzu wurden 1245 Operationen gesammelt und ausgewertet. Instabilität, Infektion und aseptische Lockerungen stellen die Hauptgründe für eine Revisionsoperation dar. Es wurden zusätzlich verschiedene Zeiträume zwischen Primärimplantation und Revision unterteilt und die jeweiligen Gründe ermittelt. N2 - Recent years have shown an increasing number of knee arthroplasty implantations with raising numbers of revisions as a result. This study has investigated into the reasons of revisions. For this purpose 1245 operations were collected and evaluated. Instability, periprosthetic infection and aseptic loosening are the main reasons for revision surgery. In addition, different time periods between primary implantation and revision were subdivided and the respective reasons were identified. KW - Reoperation KW - Knieprothese KW - knee arthroplasty KW - Revision KW - revision surgery Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-214034 ER - TY - JOUR A1 - Boelch, S. P. A1 - Jakuscheit, A. A1 - Doerries, S. A1 - Fraissler, L. A1 - Hoberg, M. A1 - Arnholdt, J. A1 - Rudert, M. T1 - Periprosthetic infection is the major indication for TKA revision – experiences from a university referral arthroplasty center JF - BMC Musculoskeletal Disorders N2 - Background: We hypothesized, that periprosthetic joint infection (PJI) accounts for the major proportion of first (primary) and repeated (secondary) Total Knee Arthroplasty revisions at our university referral arthroplasty center. Methods: One thousand one hundred forty-three revisions, performed between 2008 and 2016 were grouped into primary (55%) and secondary (45%) revisions. The rate of revision indications was calculated and indications were categorized by time after index operation. The odds ratios of the indications for primary versus secondary revision were calculated. Results: In the primary revision group PJI accounted for 22.3%, instability for 20.0%, aseptic loosening for 14.9% and retropatellar arthrosis for 14.2%. PJI (25.6%) was the most common indication up to 1 year after implantation, retropatellar arthrosis (26.8%) 1–3 years and aseptic loosening (25.6%) more than 3 years after implantation. In the secondary revision group PJI accounted for 39.7%, aseptic loosening for 16.2% and instability for 13.2%. PJI was the most common indication at any time of revision with 43.8% up to one, 35.4% 1–3 years and 39.4% more the 3 years after index operation. The odds ratios in repeated revision were 2.32 times higher (p = 0.000) for PJI. For instability and retropatellar arthrosis the odds ratios were 0.60 times (p = 0.006) and 0.22 times (p = 0.000) lower. Conclusions: PJI is the most common indication for secondary TKA revision and within one year after primary TKA. Aseptical failures such as instability, retropatellar arthrosis and aseptical loosening are the predominant reasons for revision more than one year after primary TKA. KW - knee arthroplasty KW - revision KW - failure KW - periprosthetic infection Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176983 VL - 19 IS - 395 ER - TY - JOUR A1 - Arnholdt, Jörg A1 - Kamawal, Yama A1 - Holzapfel, Boris Michael A1 - Ripp, Axel A1 - Rudert, Maximilian A1 - Steinert, Andre Friedrich T1 - Evaluation of implant fit and frontal plane alignment after bi-compartmental knee arthroplasty using patient-specific instruments and implants JF - Archives of Medical Science N2 - Introduction The goals of successful bi-compartmental knee arthroplasty are to achieve correct fit and positioning of the implant, while appropriately correcting the mechanical alignment of the leg after surgery. As these requirements are not always reliably fulfilled using off-the-shelf implant systems, newer approaches for bi-compartmental resurfacing have been explored. Material and methods In this article we report the radiographic results of 30 patients with anteromedial osteoarthritis (OA) who were treated with a novel patient-specific fixed-bearing bi-compartmental knee resurfacing system using custom-made implants and instruments. Utilizing standardized pre- and postoperative radiographic analyses (based on anterior-posterior and lateral, anterior-posterior weight-bearing full-length radiographs, patella skyline views and preoperative computed tomography (CT) scanning) implant fit and positioning as well as correction of the mechanical axis (hip-knee-ankle angle, HKA) were determined. Results On average, HKA was corrected from 173.4 ±3.47° preoperatively to 179.4 ±2.85° postoperatively. The coronal femoro-tibial angle was corrected on average 5.61°. The preoperative tibial slope measured on lateral views was 6.38 ±2.4°, while the average slope in the CT-based planning protocol (iView) was 6.14 ±2.40°. Postoperative lateral tibial slope was determined to be 5.77 ±1.97°. The thickness of the posterior femoral cuts was measured intraoperatively and, in all cases, corresponded well to the targeted thickness of the cuts provided by the iView. The joint line was preserved in all cases and the average Insall-Salvati index was 1.078 ±0.11 pre- and 1.072 ±0.11 postoperatively. The fit of the implant components measured by over- or underhang was excellent throughout (< 1.01 mm). Conclusions Custom-made bicompartmental knee arthroplasty can ensure optimized fitting and positioning of the implant with restoration of the leg axis. These implants could be considered as an alternative primary solution for knee surgeons treating bi-compartmental disease. KW - implant fit KW - bi-compartmental knee arthoplasty KW - bi-compartmental KW - implant positioning KW - knee osteoarthritis KW - knee arthroplasty KW - patient-specific KW - knee alignment Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159668 VL - 14 IS - 6 ER - TY - THES A1 - Bischof, Antje T1 - Ergebnisse der Knieendoprothetik bei M. Ahlbäck : Unikondyläre versus Bikondyläre Prothese T1 - Knee arthroplasty for spontaneous osteonecrosis of the knee: unicompartmental vs bicompartmental knee arthroplasty. N2 - Die vorliegende Studie berichtet erstmals über den Vergleich einer uni- mit einer bikondylären Endoprothese zur Therapie des M. Ahlbäck im Spätstadium. Da diese Osteonekrose nur das mediale Kompartiment betrifft, liegt die Indikation für eine unikompartimentelle Prothese vor. Trotzdem wurde entsprechend den Erfahrungen der Operateure in unserer Klinik seit 1988 häufiger eine bikondyläre Prothese inmplantiert. In der der Literatur findet sich bis heute keine einheitliche Meineung zu diesem Thema und es gibt nur wenige Studien zum M. Ahlbäck, da diese Erkrankung sehr selten auftritt. Daher wurde diese Studie konzipiert, mit dem Ziel, die Ergebnisse der unikondylären gegenüber der bikondylären Prothese zu vergleichen. In diese Studie wurden 37 Patienten (39 Knie) mit der Diagnose M. Ahlbäck eingeschlossen. Die prä- und intraoperativen klinischen und röntgenologisch Daten wurden retrospektiv erfaßt. Daraufhin wurden die Patienten bei einem Follow up nach durchschnitllich 6,6 (0,75-16,75) Jahren nochmals klinisch und röntgenologisch untersucht. Aufgrund der geringen Inzidenz des M. Ahlbäck war die Studie auf eine kleine Fallzahl beschränkt. Zusammenfassend kann gesagt werden, daß in allen klinischen und röntgenologischen Beobachtungen sowie in der Analyse der berechneten Scores die bikondyläre Prothese der unikondylären überlegen war. Die Verankerung der unikondylären Prothese im femoralen Knochenlager scheint aufgrund der Nekrosezone beim M. Ahlbäck nicht ausreichend gewährleistet zu sein. Daher empfehlen wir die bevorzugte Implantation einer bikondylären Prothese gegenüber einem unikondylären Modell für die operative Therapie des M. Ahlbäck. N2 - Spontaneous osteonecrosis of the knee (SON) is an osteonecrosis that mainly affects the medial femoral condyle. In endstage SON, knee arthroplasty is the therapy of choice. Because of the unicompartimental nature of the knee, unicondylar knee arthroplasty is considered an ideal implant for treatment of this condition. The purpose of this study was to prove that the long-term results of unicondylar implants are better than the results of bicondylar implants for the treatment of SON. All patients treated for SON between 1984 and 2000 have been recorded. Two groups were formed according to the implant used. In all patients the preoperative radiograph was analyzed according to stage and size of the osteonecrotic lesion and the osteoarthritic changes. Postoperatively, the Knee Society Score and the radiograph were recorded. Thirty-nine patients were included in this study, of which 23 patients were treated by a unicondylar implant and 16 by a bicondylar implant. On a short-term basis, unicondylar implants had better clinical results; however, on a long-term basis bicondylar implants were better. In comparison, only unicondylar implants had to be revised. Radiolucency lines were mainly observed in patients with unicondylar impants and large areas of osteonecrosis. Our long-term results suggest that patients with SON are better treated by bicondylar implants. The reasons for the higher failure rate for unicondylar implants are poor bone stock and secondary arthritic changes. KW - M. Ahlbäck KW - Knieendoprothetik KW - unikondylär KW - bikondylär KW - Spontane Osteonekrose KW - spontaneous osteonecrosis KW - unicondylar KW - knee arthroplasty KW - bicompartmental KW - unicompartmental Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-20957 ER -