Unilaterale mediale Schlittenprothesen mit patientenspezifischer Instrumentierung – Planungsgenauigkeit, Zeitersparnis und Kosteneffektivität

Zusammenfassung

Hintergrund: Seit einigen Jahren werden patientenspezifische Instrumente (PSI) für den Einsatz in der Knieendoprothetik stark beworben. Durch ihren Gebrauch sollen die Passgenauigkeit der Prothesenkomponenten, Größe und Ausrichtung betreffend, verbessert, Operationszeit eingespart und Kosten gesenkt werden. Ob die Anwendung von PSI in der Implantation von medialen unikondylären Schlittenprothesen vorteilhaft ist, ist bisher noch unklar. Patienten/Material und Methoden: Die Daten von 22 Patienten (24 Knie) wurden retrospektiv ausgewertet. Im Fokus des Interesses stand die Verlässlichkeit der präoperativen Planung – auch in Abhängigkeit zum Erfahrungsgrad des Operateurs – sowie die Auswertung von Operationszeiten und Kosteneffektivität der PSI-Technologie. Ergebnisse: Die präoperative Planung musste in einer Vielzahl der Fälle intraoperativ angepasst werden, um ein optimales Ergebnis zu erreichen. Die femorale Komponente musste in 41,7 % aller Fälle intraoperativ verändert werden, die tibiale in 58,3 % und das Inlay in 87,5 %. Weniger erfahrene Operateure wichen häufiger von der Planung ab als erfahrenere. Die Operationszeiten verlängerten sich unter Einsatz der PSI-Technologie. Der PSI-Einsatz und der Erfahrungsgrad des Operateurs waren Hauptprädiktoren hierfür. Die Operation verteuerte sich um ca. 1200 € pro Patient, wenn PSI genutzt wurden. Schlussfolgerung: Die erhofften Vorteile der PSI-Technologie konnten mit der vorliegenden Erhebung nicht belegt werden. Derzeit überwiegen noch die Nachteile im Sinne von Mehrkosten und längeren Operationszeiten bei mangelnder Planungsverlässlichkeit.

Abstract

Background: In the past few years, patient-specific instrumentation (PSI) in knee endoprosthetics has been energetically marketed. PSI can enhance the accuracy of the size and alignment of the prosthesis components. It should also be possible to reduce hospital costs and operating time. It remains unclear whether these putative advantages are achieved in medial unicompartmental knee arthroplasty (UKA). Patients/Material and Methods: Data from 22 patients (24 knees) were analysed retrospectively. The focus was on the reliability of preoperative surgical planning – particularly with regards to the level of experience of the five surgeons involved, who were split into two groups depending on their level of experience, as defined by EndoCert®. Another focus was on the evaluation of actual surgical time and cost effectiveness using PSI. Results: In order to achieve an optimal outcome, preoperative surgical planning had to be modified intraoperatively to a great extent. The femoral component had to be adjusted intraoperatively in 41.7 % of all cases, the tibial component in 58.3 % and the polyethylene insert in 87.5 %. Surgeons equipped with less experience had to change preoperative planning more often than the more experienced surgeons. Utilising PSI increased the operating time of both the less experienced and the more experienced surgeons. PSI planning and lack of surgical experience were the main predictors of increased surgical time. Instead of lowering costs, utilizing PSI increased surgical costs by nearly 1300 $ per case. This was due to increased operating time, license fees and extraordinary expenditure for MRI scans. Conclusion: The advertised advantages of PSI were not supported by the data analysed. On the contrary, this technology leads to additional costs, greater operating time and insufficient accuracy in preoperative planning. As not a single study has yet demonstrated better outcomes in terms of alignment and/or function with PSI than with standard instrumentation, additional data are required before PSI can be recommended for routine use in medial UKA.

Schlüsselwörter

mediale unikondyläre Schlittenprothese - patientenspezifische Instrumente - Planungsgenauigkeit

Key words

medial unicompartmental knee arthroplasty - patient-specific instruments - preoperative planning accuracy

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