A 2 yr longitudinal radiographic study examining the effect of a bisphosphonate
(risedronate) upon subchondral bone loss in osteoarthritic knee patients.
Author(s): Buckland-Wright JC, Messent EA, Bingham CO 3rd, Ward RJ, Tonkin C.
Affiliation(s): Department of Applied Clinical Anatomy, King's College London School of Medicine,
Hodgkin Building, Guy's Campus, London Bridge, London SE1 1UL, UK.
chris.buckland-wright@kcl.ac.uk
Publication date & source: 2007, Rheumatology (Oxford). , 46(2):257-64
OBJECTIVES: To determine whether risedronate (RIS) slows down trabecular bone
loss in the medial compartment of the proximal tibia, a characteristic of
patients with progressive knee osteoarthritis (OA).
METHODS: Initially, 100 patients were randomly selected from each treatment group
(each N approximately 300) comprising placebo and RIS 5 mg/day, 15 mg/day and 50
mg/week from a double blind, multi-centre, placebo-controlled, 2 yr investigation
of OA knee patients in North America. Using fluoroscopic semi-flexed standard
radiography, baseline and exit knee radiographs were digitized by laser scanner.
Following computerized measurement of minimum medial compartment joint space
width, each group was subdivided into joint space narrowing (JSN) non-progressor
or JSN-progressor (JSN >or=0.6 mm measured at any point post-baseline).
Computerized method of fractal signature analysis (FSA) quantified longitudinal
changes separately in horizontal and vertical trabeculae in region of interest
(three-fourth width of tibial compartment x 6 mm height) in the medial
compartment. Following the initial study, all JSN-progressor knees within the
entire patient cohort (N = 1232) were similarly analysed.
RESULTS: OA knees in JSN non-progressor group had a slight decrease in FSA for
vertical and horizontal trabeculae and showed no drug effect. In JSN-progressor
knees, bone loss was greater in both placebo and RIS 5 mg/day groups compared
with those in RIS 15 mg/day group in which trabeculae were retained, and in the
RIS 50 mg/week group in which the vertical trabecular number increased
significantly (P < 0.05).
CONCLUSION: This preliminary study showed that patients with marked cartilage
loss (JSN>or=0.6 mm) receiving RIS 15 mg/day retained vertical trabecular
structure, and those receiving RIS 50 mg/week increased vertical trabecular
number, thereby preserving the structural integrity of subchondral bone in knee
OA.
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