AimsAn evidence-based radiographic Decision Aid for meniscal-bearing
unicompartmental knee arthroplasty (UKA) has been developed and
this study investigates its performance at an independent centre.Patients and MethodsPre-operative radiographs, including stress views, from a consecutive
cohort of 550 knees undergoing arthroplasty (UKA or total knee arthroplasty;
TKA) by a single-surgeon were assessed. Suitability for UKA was
determined using the Decision Aid, with the assessor blinded to
treatment received, and compared with actual treatment received, which
was determined by an experienced UKA surgeon based on history, examination,
radiographic assessment including stress radiographs, and intra-operative
assessment in line with the recommended indications as described
in the literature.ResultsThe sensitivity and specificity of the Decision Aid was 92% and
88%, respectively. Excluding knees where a clear pre-operative plan
was made to perform TKA, i.e. patient request, the sensitivity was
93% and specificity 96%. The false-positive rate was low (2.4%)
with all affected patients readily identifiable during joint inspection
at surgery.In patients meeting Decision Aid criteria and receiving UKA,
the five-year survival was 99% (95% confidence intervals (CI) 97
to 100). The false negatives (3.5%), who received UKA but did not
meet the criteria, had significantly worse functional outcomes (flexion
p < 0.001, American Knee Society Score - Functional p < 0.001,
University of California Los Angeles score p = 0.04), and lower
implant survival of 93.1% (95% CI 77.6 to 100).ConclusionThe radiographic Decision Aid safely and reliably identifies
appropriate patients for meniscal-bearing UKA and achieves good
results in this population. The widespread use of the Decision Aid
should improve the results of UKA.Cite this article: Bone Joint J 2016;98-B(10
Suppl B):3–10.