Randomized crossover trial of hand and hydrostatic casting for custom lower limb prosthetic sockets: Assessing socket comfort and fabrication time

by Stefania Fatone, Amy Gravely, Andrea Giovanni Cutti, Andrew H. Hansen, Steven A. Gard, on behalf of the Residual Limb Shape Capture Group

The aim of this study was to compare diagnostic sockets made by hand casting and standing hydrostatic pressure casting in persons with lower limb amputation. This multi-site, single-masked, randomized crossover trial (ClinicalTrials.gov NCT04141748) involved a prosthetist at each site taking one cast by hand (H) and another using hydrostatic casting (S). The process of casting, rectifying and modifying a diagnostic socket was timed in minutes. Socket comfort score (SCS) was assessed during static fitting of the diagnostic socket before (initial) and after (final) any modifications were made by the prosthetist. Difference scores for comfort and timing were calculated for each pair of casts within prosthetist. Bootstrapping methods were used to determine if the mean difference scores were significantly different from zero. Eighty participants with unilateral lower limb amputation were enrolled, with 75 completing the study. The initial SCS was significantly better in the transfemoral amputation group (TFA, n = 24) for the socket made from hand casting (H: 7.1 ± 1.9, S: 6.5 ± 2.2; p = 0.043). The final SCS was significantly better in the transtibial amputation group (TTA, n = 51) for the socket made from hydrostatic casting (H: 7.5 ± 2.0, S: 8.1 ± 1.3; p = 0.025). Total fabrication time for hydrostatic casting was significantly greater than hand casting (H: 42.1 ± 15.6, S: 48.0 ± 10.7; p = 0.001). It took significantly more time to cast (H: 10.6 ± 5.5, S: 23.7 ± 6.1; p