Validation of the contralateral side as reference for selecting radial head implant sizes

Abstract

PurposeIn arthroplasty of comminuted radial head fractures, the contralateral radial head diameter can be used as reference for implant selection. However, potential bilateral asymmetry may result in a mismatch of the implant with the native bone. Therefore, our purpose was to evaluate anatomical right-to-left differences of radial head diameters. We also compared conventional two-dimensional (2D) with three-dimensional (3D) measurements.MethodsWe used bilateral CT-scans from 25 intact proximal radius pairs of right-handed adult subjects to obtain 50 3D radial head models. After contralateral matching, diameters were calculated using a 3D-based method using an automated circle-fit in standardized cross-sections at the widest level midway through the radial head. The 3D-based diameters were compared to orthogonal line measurements in standard axial CT-slices.ResultsThree-dimensional analysis yielded a radial head diameter of 23.0 ± 1.7 mm. The dominant right side was significantly wider, with right-to-left differences of 0.2 ± 0.4 mm, with a maximum of 0.9 mm. The 2D-based diameter was 22.9 ± 1.7 mm, which was 0.1 ± 0.3 mm smaller compared to corresponding 3D-based diameter.ConclusionsIn healthy radial heads, the diameter was biased to the dominant right side, but individual differences were not larger than 1 mm. Compared to implant designs, in which diameter increments are usually 2 mm, this right-bias is not clinically relevant, as it would not affect implant selection. Therefore, the contralateral side can be considered a suitable reference. In clinical practice, the surgeon could estimate this diameter using standard axial CT slices, since its difference with the 3D-based evaluation was also relatively small compared to implant sizing increments.

Three‐dimensional analysis of shape variations and symmetry of the fibula, tibia, calcaneus and talus

“…; Ten Berg et al. ]. Third, the unaffected contralateral side usually serves as an intra‐subject control or as a shape template in research studies that assess whether a bone shape can be a risk factor for the onset of an injury (e.g.…”

Bilateral symmetry of the subtalar joint facets and the relationship between the morphology and osteoarthritic changes

“…In general, literature describing the bilateral symmetry of the hindfoot is scarce (Shultz and Nguyen, 2007;Islam et al, 2014;Tümer et al, 2018). This is remarkable since many surgeons use the contralateral noninjured side as reference for anatomical reduction in case of a fractured bone (Pierre et al, 2010;Dobbe et al, 2011;Young et al, 2013;Ten Berg et al, 2016). Even less literature is available describing the symmetry of the articulating facets.…”

Partial radial head arthroplasty: two case reports with minimum 8-year follow-up

“…Owing to the patient's young age and the fact that he had compromise of the coronoid, the radial head, and both collateral ligaments, it was necessary to restore the radial head capacity for load bearing and stability. Because more than half of the radial head was still intact and symmetry had been demonstrated in the right and left elbows, it was reasoned that the mechanics could be accurately restored by using contralateral 3-dimensional (3D) radial head measurements to design a prosthesis that aligned corresponding landmarks to re-create the missing bone 1, 6…”

“…At her 4-year clinical follow-up, she rated her elbow as “greatly improved” and a SOD score2, 3, 6 of 8/10 compared to before her surgery. Elbow range of motion was 40°-130° in extension-flexion with 80°-70° of pronation-supination.…”

“…Throughout the postoperative course, the patient noted pain in the cold weather and with heavy lifting but was otherwise able to function in her activities of daily living with little difficulty. At final follow-up 8 years after surgery, her visual analog scale pain score at rest was 4/10, she scored 55 on the American Shoulder and Elbow Surgeons assessment and 65 on the Mayo Elbow Performance Score, and she rated her elbow as “improved” and a SOD score of 6/10 compared to before her surgery 2, 3, 6…”