京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22831号 / 医博第4670号 / 新制||医||1047(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 安達 泰治, 教授 別所 和久, 教授 妻木 範行 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

The aim of this thesis was to establish the long-term outcomes of the Oxford medial Unicompartmental Knee Arthroplasty (OUKA), define patient selection criteria and to develop and externally validate an evidence based method of patient selection for this procedure. In the hands of the developer surgeons, outcomes following medial OUKA were found to be good with an implant survival of 94% (95%CI 92 to 96) at ten-years and 91% (95%CI 83 to 98) at fifteen-years. Across the published literature, however, variation in outcomes was observed with a meta-analysis of published series of OUKA finding estimates of ten-year survival ranging from 57% to 100%, mean 88% (95%CI 85 to 90). It was identified that both increased surgical caseload (volume) and increased surgical usage (proportion of primary knee arthroplasty that are OUKA), a surrogate marker of indications, were associated with improved outcomes. Surgical usage, however, was more important, with good results following OUKA seen with high surgical usage, representing broad indications, independent of the surgical volume. This finding, coupled with differences in patient demographics and failure mechanisms between usage groups, highlighted that differences in indications for OUKA may explain the variability in outcomes observed. One reason surgeons may have a low usage is if they apply previously recommended patient factor contraindications based on age (<60 years), weight (≥82kg) and activity level (high activity). When disease factors are standardised, however, it was found that patients with these previously reported contraindications often actually did better than those without, and outcomes of knees implanted where all these factors were present were as good as where none were present. Therefore, the decision to proceed with OUKA should be based on the pathoanatomy of disease. Optimal candidates for OUKA should have full-thickness cartilage loss, with bone on bone arthritis, in the medial compartment, as knees with partial thickness cartilage loss were found to have worse functional outcomes and almost three-times the reoperation rate, predominantly for unexplained pain. Provided there was full-thickness preserved cartilage laterally and functionally normal ligaments, the presence of lateral osteophytes and the macroscopic status of the anterior cruciate ligament was not found to influence outcomes, nor did the presence of patellofemoral joint disease (with the exception of lateral facet disease with bone loss and grooving) or anterior knee pain. The pathoanatomy of disease can be identified radiologically, however, standing knee radiograph were found to perform poorly. To identify medial compartment full-thickness cartilage loss either a varus stress radiograph or fixed flexion radiograph, both at 20° flexion and aligned to the joint surface, were identified as the optimum views. To confirm preserved lateral compartment full-thickness cartilage a valgus stress radiograph at 20° flexion, aligned to the joint surface, was identified as the most appropriate technique. As stress radiographs are time and resource consuming, a novel stress device was developed in line with the IDEAL-D framework and validated against the gold standard of manual, clinician performed stress radiographs, as well as independently tested in clinical practice. Finally, to simplify patient selection, an atlas based Decision Aid, combined with a structured radiographic assessment, was developed and externally validated with an accuracy of over 90% at identifying suitability for OUKA. The routine use of this approach would be expected to standardise patient selection and ultimately translate into improved long-term outcomes.

Bakgrund: Antalet personer som genomgår knäartroplastik ökar markant i västvärlden samtidigt som den genomsnittliga vårdtiden efter genomgången knäartroplastik minskar. Tidigare forskning visar att ingreppet är väl lämpat för dagkirurgi. Det är trots detta svårt att hitta kvalitativ forskning som beskriver patientens upplevelse av att ha genomgått en knäartroplastik i dagkirurgi. Syfte: Syftet med denna studie var att beskriva patientens upplevelse av att genomgå en unikompartmentell knäartroplastik (UKA) i dagkirurgi. Metod: Denna kvalitativa intervjustudie inkluderade åtta personer som genomgått en UKA i dagkirurgi mellan 2017 och 2020. Semistrukturerade intervjuer genomfördes i mars 2020 med stöd av en intervjuguide. Deltagarna fick berätta om upplevelsen av att ha genomgått en UKA i dagkirurgi. Resultat: Resultatet visar att de flesta deltagarna var nöjda med att ha genomgått operationen i dagkirurgi. Upplevelsen av trygghet i samband med den tidiga hemgången hade ett nära samband med uppföljning samt informationen inför operationen som gav deltagarna verktyg för att hantera såväl smärta som aktiviteter i det dagliga livet (ADL) och rehabilitering i hemmet. Konklusion: För att känna trygghet i samband med att genomgå UKA i dagkirurgi har utförlig information samt tidig uppföljning en central roll i resultatet av patientens upplevelse.