Poster 174: Is Articular Width or Epicondylar Width Superior to Age to Optimize Radius of Curvature Matching in Capitellar Osteochondral Allografts?

Abstract

Objectives: There is growing interest to use matched distal humeral osteochondral allograft (OCA) for treatment of osteochondritis dissecans (OCD) of the capitellum due to concerns of donor site morbidity in osteochondral autograft transplantation surgery. Current graft match processes utilize the epicondylar width (EW) of the distal humerus, though little information is available regarding the correlation of this measurement to the radius of curvature (ROC) of the capitellum. The purpose of this study was to characterize the correlation between the EW and ROC as well as to evaluate two additional candidate parameters including patient age and the distal humeral articular width (AW). Methods: Forty patients (age ≤18) were identified for analysis. The capitellar cartilage ROC was measured on the sagittal plane of each magnetic resonance imaging (MRI) study at the level where the corresponding radial head was greatest in diameter (fig. 1). The EW (fig. 2) and the AW (fig. 3), which is bordered by the medial articular border of the trochlea and the lateral articular border of the capitellum, were also measured on the axial plane of each MRI study at maximal width. R2 correlation coefficients were calculated for ROC to EW, AW, and patient age (fig. 4). Intra-observer and inter-observer reliability measurements were performed to assess precision and validity of method. Results: The mean sagittal cartilage ROC, EW, and AW were 11.05 mm, 60.79 mm, and 44.31 mm. When measured against ROC, patient age had poor correlation with a R2 value of 0.46 whereas EW and AW demonstrated strong correlation with R2 values of 0.68 and 0.76 respectively. Intra-observer correlation coefficients were 0.93, 0.96, and 0.95 for ROC, EW, and AW respectively. Inter-observer correlation coefficients were 0.79, 0.94, and 0.94 for ROC, EW, and AW, respectively. Conclusions: Our results suggest that both AW and EW demonstrate superior correlation to capitellar ROC in comparison to age, and AW may be superior to EW. AW may be considered for utilization as a distal humeral allograft matching parameter particularly in patients that may have altered epicondylar morphology such as in the throwing athlete. [Figure: see text][Figure: see text][Figure: see text][Figure: see text]