Loss of bone mass after total hip replacement: preliminary data.
In a total of 37 females with cemented total hip replacement for monolateral coxarthrosis, of which 13 with prosthetic stem loosening, and 11 with monolateral coxarthrosis that is not prosthetized, bone mineral density (BMD) is determined by dual ray photonic absorbimetry selecting regions of interest (ROI) on the cortex of the femurs 4 cm under the lesser trochanter and on the ischium bilaterally. In females that are not prosthetized there are differences in bone mass between the two femurs and the ischium on both sides. In prosthetized patients BMD of the femur and of the ischium on the side operated on is significantly less than on the contralateral one (Student's "t" test: p < 0.001). In patients with stable prostheses, BMD of the femur operated on is greater than that in females with prosthetic stem loosening (Student's "t" test: p < 0.000). Based on a comparison between these two groups we did not observe any other significant differences in BMD among the ROI analyzed. BMD was correlated with the amount of time since surgery only in the ROIs in prosthetized femurs. The study confirms the significant bone resorption of the cortex in prosthetized femurs and documents analogously significant reduction in BMD in the ischium on the side operated on. Finally, it indicates that prosthetic stem loosening may be associated with loss of BMD in the femoral cortex which is significantly greater than that observed, during analogous periods of time in stable implants.
Gnudi
S
S
Servizio di Medicina Interna, Istituto Ortopedico Rizzoli, Bologna.
Malavolta
N
N
Ripamonti
C
C
Calderoni
P
P
Dallari
D
D
Gualtieri
G
G
D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D015519:Bone Density; D001862:Bone Resorption / Q000503:physiopathology*; D005260:Female; D005269:Femur / Q000503:physiopathology; D006801:Humans; D007512:Ischium / Q000503:physiopathology; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000503:physiopathology / Q000601:surgery; D011475:Prosthesis Failure