Changes in tibial bone mass after primary cementless and revision cementless total hip arthroplasty in canine models.
The purpose of this study was to examine right-left differences in tibial bone mass after unilateral (left) cementless total hip arthroplasty (THA). Of 39 dogs with THAs, 9 had primary cementless porous-coated femoral stems for 6 months and 15 had similar stems for 2 years. Five dogs had aseptically failed cemented hips, and 10 had aseptically failed cemented hips that were revised with cementless porous-coated femoral stems (5 without bone graft and 5 with autogenous bone graft). These animals were sacrificed 6 months after the revision surgery. The primary cementless dogs showed no right-left difference in tibial bone mineral content (BMC) or cortical bone cross-sectional geometry after 6 months, but after 2 years there was a distal right-left difference in BMC of 6% caused by expansion of the medullary canal in the tibia of the operated limb. Tibial BMC was more than 20% lower in the operated limb of the failed cemented dogs, approximately 15% lower in the nongrafted group, and 7% lower in the grafted group. The right-left tibial difference in BMC in the 2-year primary cementless group is most probably because of subclinical disuse of the operated limb. Among the dogs with failed cemented stems, the lower right-left difference in the two revised groups compared with the non-revised group suggests that improved limb function after cementless revision THA may cause gain of previously lost bone.
Goethgen
C B
CB
Department of Orthopedic Surgery, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612.
Sumner
D R
DR
Platz
C
C
Turner
T M
TM
Galante
J O
JO
D000818:Animals; D001843:Bone Cements; D015519:Bone Density / Q000502:physiology*; D016723:Bone Remodeling; D004285:Dogs; D006622:Hip Prosthesis / Q000379:methods*; D011475:Prosthesis Failure; D013977:Tibia / Q000033:anatomy & histology / Q000502:physiology* / Q000601:surgery
D001843:Bone Cements