Effect of age on progression through temporary prostheses after below-knee amputation.

Forty six patients that underwent below knee amputation for diabetes, trauma/osteomyelitis or peripheral vascular disease were studied. Healing was estimated by the rate of progression through temporary prostheses as determined weekly by the amputee rehabilitation team (physiatrist, orthopedist, physical therapist, nurse, and prosthetist). For all groups combined, mean days +/- standard error from amputation to above knee cast with pylon and foot (AKPy) were 22.9 +/- 1.9, to below knee cast with pylon and foot (BKPy) 41.6 +/- 2.8 and to laminated temporary prostheses 66.5 +/- 4.5. A regression analysis of these variables on age (range: 29 to 84 yr) showed significant positive correlations for AKPy (r = 0.34, P = 0.0214) and BKPy (r = 0.40, P = 0.0056). An analysis of variance with contrasts (Tukey's protected t) showed significant lower values (P < 0.05) for amputation to BKPy in the trauma/osteomyelitis group when compared to diabetes or peripheral vascular disease and no difference among the last two groups. However, when variables were adjusted for age (analysis of covariance with age as a covariate), the differences among groups disappeared (covariance F(2,44) = 0.9, P > 0.4). In conclusion, age, not the cause of the amputation, correlated with healing after below knee amputation as estimated by the rate of progression through temporary prostheses.