Association between expression of the bone morphogenetic proteins 2 and 7 in the repair of circumscribed cartilage lesions with clinical outcome.
BACKGROUND
Although there is much known about the role of BMPs in cartilage metabolism reliable data about the in vivo regulation in natural and surgically induced cartilage repair are still missing.


METHODS
Lavage fluids of knee joints of 47 patients were collected during surgical therapy. 5 patients had no cartilage lesion and served as a control group, the other 42 patients with circumscribed cartilage defects were treated by microfracturing (19) or by an Autologous Chondrocyte Implantation (23). The concentrations of BMP-2 and BMP-7 were determined by ELISA. The clinical status was evaluated using the IKDC Score prior to and 1 year following the operation.


RESULTS
High level expression in the control group was found for BMP-2, concentrations of BMP-7 remained below detection levels. No statistical differences could be detected in concentrations of BMP-2 or BMP-7 in the lavage fluids of knees with cartilage lesions compared to the control group. Levels of BMP-7 did not change after surgical cartilage repair, whereas concentrations of BMP-2 statistically significant increased after the intervention (p < 0.001). The clinical outcome following cartilage regenerating surgery increased after 1 year by 29% (p < 0.001). The difference of the IKDC score after 1 year and prior to the operation was used to quantify the degree of improvement following surgery. This difference statistically significant correlated with initial BMP-2 (R = 0.554, p < 0.001) but not BMP-7 (R = 0.031, n.s.) levels in the knee joints.


CONCLUSIONS
BMP-2 seems to play an important role in surgically induced cartilage repair; synovial expression correlates with the clinical outcome.
Schmal
Hagen
H
Department of Orthopedic Surgery, University of Freiburg Medical Center, Hugstetter Str 55, D-79106 Freiburg, Germany. hagen.schmal@freenet.de
Niemeyer
Philipp
P
Zwingmann
Jörn
J
Stoffel
Fabian
F
Südkamp
Norbert P
NP
Mehlhorn
Alexander T
AT
D000293:Adolescent; D000328:Adult; D000368:Aged; D055396:Bone Morphogenetic Protein 2 / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D055419:Bone Morphogenetic Protein 7 / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D002357:Cartilage Diseases / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D017690:Cell Transplantation / Q000379:methods; D019902:Chondrocytes / Q000378:metabolism / Q000637:transplantation; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012038:Regeneration / Q000502:physiology*; D015854:Up-Regulation / Q000502:physiology; D014945:Wound Healing / Q000502:physiology*; D055815:Young Adult
C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D055419:Bone Morphogenetic Protein 7