Peri-prosthetic bone mineral density after total knee arthroplasty. Cemented versus cementless fixation.
We compared peri-prosthetic bone mineral density between identical cemented and cementless LCS rotating platform total knee arthroplasties. Two matched cohorts had dual energy x-ray absorptiometry scans two years post-operatively using a modified validated densitometric analysis protocol, to assess peri-prosthetic bone mineral density. The knee that was not operated on was also scanned to enable the calculation of a relative bone mineral density difference. Oxford Knee and American Knee Society scores were comparable in the two cohorts. Statistical analysis revealed no significant difference in absolute, or relative peri-prosthetic bone mineral density with respect to the method of fixation. However, the femoral peri-prosthetic bone mineral density and relative bone mineral density difference were significantly decreased, irrespective of the method of fixation, particularly in the anterior distal portion of the femur, with a mean reduction in relative bone mineral density difference of 27%. There was no difference in clinical outcome between the cemented and cementless LCS total knee arthroplasty. However, both produce stress-shielding around the femoral implants. This leads us to question the use of more expensive cementless total knee components.
Abu-Rajab
R B
RB
Orthopaedic Department, Diabetes Centre, Southern General Hospital, 1345 Govan Road, Glasgow G51 4TF, Scotland, UK. r1abu@hotmail.com
Watson
W S
WS
Walker
B
B
Roberts
J
J
Gallacher
S J
SJ
Meek
R M D
RM
D015502:Absorptiometry, Photon / Q000379:methods; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D001843:Bone Cements; D015519:Bone Density / Q000502:physiology*; D001851:Bone Diseases, Metabolic / Q000503:physiopathology; D002484:Cementation; D005260:Female; D005269:Femur / Q000503:physiopathology; D005272:Femur Neck / Q000503:physiopathology; D006801:Humans; D007720:Knee Prosthesis; D008159:Lumbar Vertebrae / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000503:physiopathology; D012737:Sex Factors; D016896:Treatment Outcome
D001843:Bone Cements