Clinical intervention of a tighter-than-tolerated fit of aesthetic hand and finger prosthesis via controlled silicone swelling: A novel, speedier and versatile alternative method

A tighter-than-tolerated fit of aesthetic hand prosthesis is conventionally rectified by stretching the affected segment to plastic deformation. This method is not only time-consuming, but also ineffective in stretching irregular, non-cylindrical prosthesis segments apart from the "wrist and digits". This study investigates controlled silicone swelling as an alternative method of expanding aesthetic hand and finger prosthesis to address a tight fit. The technique of "controlled" swelling that minimizes oil uptake to as little as is necessary to achieve the desired magnitude of elastomer expansion was demonstrated using experimental test samples. Brush-coats of a cosmetics-grade oil, KF-96A-10CS, 2 a time, were applied on Cosmesil (TM) samples to obtain elastomer expansion. The same technique of staggered oil delivery was used on tight-fitting segments of patients' prosthesis, with test-fitting of each incremental expansion till satisfactory outcomes were achieved. Percentage circumference increases in swelled test samples and in all rectified/patients' prostheses were then compared to validate the effectiveness of the method. Circumference increases in the test samples after each 2 coats were significantly different (P <.001). Representative (unreinforced) Samples 1, 2, and 3 recorded circumferential increases of 4.0% to 11.4% within 30 minute after swelling by 2.6% to 9.7% from 2 to 6 oil coats. This largely correlated with patient data, where circumferential increases of 3.6% to 9.5% from 2 to 6 oil coats were collectively recorded in all fit-rectified finger prostheses. Swelling in the expanded proximal segment of all 24 finger prostheses was estimated to be within 9.7%. Of these, 22 (92%) required 2 to 4 oil coats, inferring a lower still swelling of 6.5%. The rapid and consistent elastomer expansion enabled prosthetic fit rectification to be achieved in a much shortened time. Clinical outcomes indicated that low swelling magnitudes involving small amounts of 2 to 6 brush-coats of oil have no adverse effects on the prostheses. None of the participating patients had reported any incidence of discernible change in all of the important properties of their prostheses. Outcomes based on the Cosmesil (TM)-KF-96A-10CS elastomer-oil combination demonstrated that controlled silicone swelling involving minimal use of oil is an effective method of intervention for a tighter-than-tolerated prosthetic fit of silicone hand and fingers.