Evidence from Raman spectroscopy of a putative link between inherent bone matrix chemistry and degenerative joint disease.
OBJECTIVE
Osteoarthritis (OA) is a common debilitating disease that results in degeneration of cartilage and bone in the synovial joints. Subtle changes in the molecular structure of the subchondral bone matrix occur and may be associated with cartilage changes. The aim of this study was to explore whether the abnormal molecular changes observed in the matrix of OA subchondral bone can be identified with Raman spectroscopy.


METHODS
Tibial plateaus from patients undergoing total knee replacement for OA (n = 10) were compared with healthy joints from patients undergoing leg amputation (n = 5; sex- and laterality-matched) and with non-OA cadaveric knee specimens (n = 5; age-matched). The samples were analyzed with Raman spectroscopy, peripheral quantitative computed tomography, and chemical analysis to compare changes in defined load-bearing sites in both the medial and lateral compartments.


RESULTS
OA subchondral bone matrix changes were detected by Raman spectroscopy. Within each cohort, there was no spectral difference in bone matrix chemistry between the medial and lateral compartments, whereas a significant spectral difference (P < 0.001) was observed between the non-OA and OA specimens. Type I collagen chain ratios were normal in the non-OA specimens but were significantly elevated in the OA specimens.


CONCLUSIONS
In comparing the results of Raman spectroscopy with those obtained by other standard techniques, these findings show, for the first time, that subchondral bone changes, or inherent differences, exist in both the medial and lateral (beneath intact cartilage) compartments of OA knees. The development of Raman spectroscopy as a screening tool, based on molecular-specific modifications in bone, would facilitate the identification of clinical disease, including early molecular changes.
Institute of Orthopaedics and Musculoskeletal Science, University College London, and Royal National Orthopaedic Hospital, Stanmore, UK.
Jemma G
JG
Kerns
Panagiotis D
PD
Gikas
Kevin
K
Buckley
Adam
A
Shepperd
Helen L
HL
Birch
Ian
I
McCarthy
Jonathan
J
Miles
Timothy W R
TW
Briggs
Richard
R
Keen
Anthony W
AW
Parker
Pavel
P
Matousek
Allen E
AE
Goodship
D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D015519:Bone Density; D001857:Bone Matrix / Q000737:chemistry* / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D024042:Collagen Type I / Q000032:analysis; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D020370:Osteoarthritis, Knee / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D013059:Spectrum Analysis, Raman; D013977:Tibia / Q000378:metabolism / Q000473:pathology
D024042:Collagen Type I