Shell osteochondral allografts of the knee: comparison of mr imaging findings and immunologic responses.
OBJECTIVE
To define the magnetic resonance (MR) imaging appearance of shell osteochondral allografts of the knee and compare the MR findings with antibody responses.


METHODS
Thirty-six grafts were evaluated with a 1.5-T unit with T1-, intermediate-, and T2-weighted, and three-dimensional spoiled gradient-recalled MR imaging at 3, 6, 12, 24, and/or 36 months after surgery. Nineteen patients underwent imaging serially. Two osteoradiologists scored by consensus host marrow edema, thickness of graft-host interface, signal intensity of graft marrow, cyst formation, joint effusion, articular cartilage defects, and surface collapse. Patients were divided into antibody-positive (AP) (n = 11) and antibody-negative (AN) (n = 25) groups evenly distributed across the different time points on the basis of results of anti-human leukocyte antigen antibody screening. MR findings for the two groups were compared.


RESULTS
AP patients demonstrated greater mean edema (P<.002), thicker interface (P<.03), and more abnormal graft marrow (P<.04) than AN patients, and they had a higher proportion of surface collapse (P<.03).


CONCLUSIONS
Humoral immune responses were associated with more inflammation and less complete incorporation after allograft placement. MR imaging shows promise as a surrogate biomarker for success of shell osteochondral allograft implantation.
Department of Radiology, University of California, San Diego, USA.
C B
CB
Sirlin
J
J
Brossmann
R D
RD
Boutin
M N
MN
Pathria
F R
FR
Convery
W
W
Bugbee
R
R
Deutsch
L K
LK
Lebeck
D
D
Resnick
D000293:Adolescent; D000328:Adult; D001853:Bone Marrow / Q000276:immunology / Q000473:pathology; D001855:Bone Marrow Diseases / Q000175:diagnosis / Q000276:immunology; D016025:Bone Transplantation / Q000276:immunology*; D002356:Cartilage / Q000276:immunology / Q000637:transplantation*; D004487:Edema / Q000175:diagnosis / Q000276:immunology; D005260:Female; D005269:Femur / Q000276:immunology / Q000473:pathology; D006084:Graft Rejection / Q000175:diagnosis* / Q000276:immunology; D006801:Humans; D007518:Isoantibodies / Q000097:blood; D007718:Knee Injuries / Q000175:diagnosis / Q000276:immunology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D013977:Tibia / Q000276:immunology / Q000473:pathology; D014181:Transplantation Immunology / Q000276:immunology; D014184:Transplantation, Homologous
D007518:Isoantibodies