Open AccessA radiological index that influences the outcome following patellofemoral joint arthroplasty: the anterior trochlea offset ratio
Author(s) -
Aweid Osama,
Ahearn Nathanael,
Metcalfe Andrew J.,
Eldridge Jonathan,
Porteous Andrew,
Murray James R.,
Porteous Andrew,
Eldridge Jonathon,
Robinson James,
Murray James,
Davies Hywel,
Howells Nick,
Clark Damian,
Putnis Sven,
Hassaballa Mo,
Bray Rachel,
Negrut Corina,
MacDonald Karen,
Miller Suzanne
Publication year - 2023
Publication title -
knee surgery, sports traumatology, arthroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.806
H-Index - 125
eISSN - 1433-7347
pISSN - 0942-2056
DOI - 10.1007/s00167-022-07085-1
Subject(s) - radiological weapon , medicine , oxford knee score , retrospective cohort study , arthroplasty , prom , intraclass correlation , logistic regression , cohort , surgery , osteoarthritis , clinical psychology , alternative medicine , pathology , obstetrics , psychometrics
Abstract Purpose Although largely successful, patellofemoral joint arthroplasty (PFA) has a less than satisfactory outcome in some patients. It was hypothesized that certain factors can be identified on radiological review that correlate with poor patient reported outcomes following PFA. Methods A retrospective cohort review of 369 patients undergoing PFA at our institution between 2005 and 2018 identified 43 “poor outcome” patients with an Oxford Knee Score (OKS) of less than 20 at 2 years follow up. These cases were matched by sex and age with 43 “good outcome” patients who had an OKS above 40 at 2 years post‐op. Multiple radiological measurements were performed including anterior trochlea offset ratio (ATOR), component flexion/extension, component varus/valgus, component to bone width ratio and retinacular index. The OKS PROM was the primary outcome of the study. Stepwise logistic regression was performed to analyze the differences in radiological indices between the two groups. Results Intraclass correlation coefficients for inter‐observer and intra‐observer reliability were 0.90–0.98 for all indices measured. The only index demonstrating statistical significance between the groups was the ATOR ( p = 0.003). The good outcome group had a mean ATOR of 0.19 whereas the poor outcome group had a mean ATOR of 0.24. Conclusions Lower ATOR on radiological review was strongly associated with improved outcomes following PFA. The surgeon should therefore take particular care to prevent increasing the anterior offset of the trochlea component when performing PFA. Level of evidence Retrospective cohort study, Level III.