Comparison of clinical, radionuclide, and radiographic features of osteoarthritis of the hands

Alterations in periarticular bone and cross talk between subchondral bone and articular cartilage in osteoarthritis

The articular cartilage and the subchondral bone form a biocomposite that is uniquely adapted to the transfer of loads across the diarthrodial joint. During the evolution of the osteoarthritic process biomechanical and biological processes result in alterations in the composition, structure and functional properties of these tissues. Given the intimate contact between the cartilage and bone, alterations of either tissue will modulate the properties and function of the other joint component. The changes in periarticular bone tend to occur very early in the development of OA. Although chondrocytes also have the capacity to modulate their functional state in response to loading, the capacity of these cells to repair and modify their surrounding extracellular matrix is relatively limited in comparison to the adjacent subchondral bone. This differential adaptive capacity likely underlies the more rapid appearance of detectable skeletal changes in OA in comparison to the articular cartilage. The OA changes in periarticular bone include increases in subchondral cortical bone thickness, gradual decreases in subchondral trabeular bone mass, formation of marginal joint osteophytes, development of bone cysts and advancement of the zone of calcified cartilage between the articular cartilage and subchondral bone. The expansion of the zone of calcified cartilage contributes to overall thinning of the articular cartilage. The mechanisms involved in this process include the release of soluble mediators from chondrocytes in the deep zones of the articular cartilage and/or the influences of microcracks that have initiated focal remodeling in the calcified cartilage and subchondral bone in an attempt to repair the microdamage. There is the need for further studies to define the pathophysiological mechanisms involved in the interaction between subchondral bone and articular cartilage and for applying this information to the development of therapeutic interventions to improve the outcomes in patients with OA.

Hand osteoarthritis--a heterogeneous disorder

Hand osteoarthritis (OA) is a prevalent disorder. Hand OA is not one single disease, but a heterogeneous group of disorders. Radiographic signs of hand OA, such as osteophytes or joint space narrowing, can be found in up to 81% of the elderly population. Several hand OA subsets--such as nodal interphalangeal OA, thumb base OA and erosive OA--can be discriminated. Furthermore, the experience of symptoms and the course of the disease differ between patients. Studies that used well-defined study populations with longitudinal follow-up have shown that similarities and differences can be observed in the pathogenesis, epidemiology and risk factors of the various hand OA subsets. Erosive OA in particular, characterized by erosive lesions on radiographical images, has a higher clinical burden and worse outcome than nonerosive hand OA. Imaging modalities (such as ultrasonography) have increased our knowledge of the role of inflammation of the disease. Our understanding of the heterogeneous nature of hand OA can eventually lead to increased knowledge of the pathogenesis of, and ultimately new treatment modalities for, this complex disease.

Effect of a blend of comfrey root extract (Symphytum officinale L.) and tannic acid creams in the treatment of osteoarthritis of the knee: randomized, placebo-controlled, double-blind, multiclinical trials

OBJECTIVE

The purpose of this study was to determine the effect of 2 concentrations of topical, comfrey-based botanical creams containing a blend of tannic acid and eucalyptus to a eucalyptus reference cream on pain, stiffness, and physical functioning in those with primary osteoarthritis of the knee.

METHODS

Forty-three male and female subjects (45-83 years old) with diagnosed primary osteoarthritis of the knee who met the inclusion criteria were entered into the study. The subjects were randomly assigned to 1 of 3 treatment groups: 10% or 20% comfrey root extract (Symphytum officinale L.) or a placebo cream. Outcomes of pain, stiffness, and functioning were done on the Western Ontario and MacMaster Universities Osteoarthritis Index. Participants applied the cream 3× a day for 6 weeks and were evaluated every 2 weeks during the treatment.

RESULTS

Repeated-measures analyses of variance yielded significant differences in all of the Western Ontario and MacMaster Universities Osteoarthritis Index categories (pain P < .01, stiffness P < .01, daily function P < .01), confirming that the 10% and 20% comfrey-based creams were superior to the reference cream. The active groups each had 2 participants who had temporary and minor adverse reactions of skin rash and itching, which were rapidly resolved by modifying applications.

CONCLUSION

Both active topical comfrey formulations were effective in relieving pain and stiffness and in improving physical functioning and were superior to placebo in those with primary osteoarthritis of the knee without serious adverse effects.

Whole-body bone scintigraphy provides a measure of the total-body burden of osteoarthritis for the purpose of systemic biomarker validation

OBJECTIVE

To evaluate the association of serum and synovial fluid cartilage oligomeric matrix protein (COMP) with systemic and local measures of osteoarthritis (OA) activity by bone scintigraphy.

METHODS

Samples of serum and knee joint synovial fluid (275 knees) were obtained from 159 patients with symptomatic OA of at least 1 knee. Bone scintigraphy using (99m)Tc-labeled methylene diphosphonate was performed, and early-phase knee scans and late-phase whole-body bone scans of 15 additional joint sites were scored semiquantitatively. To control for within-subject correlations of knee data, generalized linear modeling was used in the correlation of the bone scan scores with the COMP levels. Principal components analysis was used to explore the contribution of each joint site to the variance in serum COMP levels.

RESULTS

The correlation between synovial fluid and serum COMP levels was significant (r = 0.206, P = 0.006). Synovial fluid COMP levels correlated most strongly with the early-phase knee bone scan scores (P = 0.0003), even after adjustment for OA severity according to the late-phase bone scan scores (P = 0.015), as well as synovial fluid volumes (P < 0.0001). Serum COMP levels correlated with the total-body bone scan scores (r = 0.188, P = 0.018) and with a factor composed of the bone scan scores in the shoulders, spine, lateral knees, and sacroiliac joints (P = 0.0004).

CONCLUSION

Synovial fluid COMP levels correlated strongly with 2 indicators of knee joint inflammation: early-phase bone scintigraphic findings and synovial fluid volume. Serum COMP levels correlated with total-body joint disease severity as determined by late-phase bone scintigraphy, supporting the hypothesis that whole-body bone scintigraphy is a means of quantifying the total-body burden of OA for systemic biomarker validation.

Role of bone in osteoarthritis pathogenesis

Much of the attention in developing diagnostic tools and therapeutic interventions for the management of osteoarthritis (OA) has focused on the preservation or repair of articular cartilage. It is clear that all of the joint components, including the ligaments, tendons, capsule, synovial lining, and periarticular bone, undergo structural and functional alterations during the course of OA progression. This article focuses on the specific skeletal features of OA and the putative mechanisms involved in their pathogenesis.

Osteophytes, juxta-articular radiolucencies and cancellous bone changes in the proximal tibia of patients with knee osteoarthritis

OBJECTIVE

To determine differences in tibial cancellous bone organisation in knee osteoarthritis (OA) between the central weight-bearing region and juxta-articular radiolucencies adjacent to small, medium or large marginal osteophytes.

METHODS

Patients with medial compartment OA (n = 60; F = 39), mean (SD) age 60.0 (9.7) years, and non-OA reference subjects (n = 21; F = 5), mean (SD) age 36.8 (11.5) years, had x4 macroradiographs digitised by laser scanner. Using a modified Osteoarthritis Research Society (OARS) Atlas, right and/or left knees were graded according to marginal osteophyte size into those with small (n = 30), medium (n = 30) or large (n = 27) marginal osteophytes, identified as OPH1, OPH2 and OPH3, respectively. Non-OA knees (n = 30) were anatomically normal. Computerised method of Fractal Signature Analysis (FSA) quantified differences in cancellous bone structure between non-OA and osteophyte subgroups at two regions of interest (ROIs); central weight-bearing and tibial margin.

RESULTS

Compared to non-OA, vertical trabecular number increased significantly (P < 0.05) in all osteophyte subgroups (width range 0.12-1.14 mm) within both ROIs. In OPH3, this increase was significantly (P < 0.05) greater compared to OPH2 in the central ROI, and to OPH2 and OPH1 in the marginal ROI at most trabecular widths (0.12-1.14 mm). In the marginal ROI, compared to non-OA, horizontal trabeculae number decreased in all osteophyte subgroups. This decrease was significantly greater in OPH3 compared to OPH2 and OPH1 at small to medium trabecular widths (0.12-0.54 mm).

CONCLUSION

Compared to disease associated bone loss at the central ROI of the tibia, the extent of juxta-articular bone loss appears to be associated with the size of the marginal osteophytes.

Characteristics of joint degeneration in hand osteoarthritis

OBJECTIVES

To assess quantitatively the relative contribution of joint degeneration characteristics such as osteophytes (OS), joint space narrowing (JS), subchondral sclerosis (SS), subchondral cysts (SC), lateral deformity (LD) and cortical collapse (CC) to the Kellgren and Lawrence (K-L) score grade of hand osteoarthritis (OA).

METHODS

Radiographs of both hands were taken from 1245 study participants, native Chuvasha, Russian Federation. K-L score and the six above-mentioned characteristics were assessed on 15 joints of each hand. Multiple regression and correlation analyses were performed: for rows of hand joints and groups of thumb joints, and for the aforementioned rows but assigned into six age groups.

RESULTS AND CONCLUSIONS

According to the K-L grading system the relative contribution of OS to joint degeneration was high in all stages of the process. JS and SS played an important role in determining the K-L score in persons younger than 40 but less so in older people. Conversely, influence of SC and LD is insignificant at the onset of OA (i.e., in young persons), yet in older people it was a leading determinant of the K-L score. CC exerts no influence on the K-L score of OA.

Patterns of joint distribution in hand osteoarthritis: contribution of age, sex, and handedness

The most frequent site of osteoarthritis (OA) is the hands, but the pattern of hand OA development remains controversial. Understanding these patterns may assist in evaluating biological aging, determining etiology, and proposing ways of preventing hand OA. We investigated the pattern distribution of OA in hands and the influences of age, sex, and handedness on its development. The study population was comprised of Chuvashians (660 males age 18-89 years and 585 females age 18-90 years). OA development was evaluated for 15 joints of each hand according to the Kellgren and Lawrence grading scheme. Statistical analyses included Pearson correlation, cluster analysis, MANCOVA, and linear and polynomial regression. OA changes first appeared in subjects <30 years of age. Metacarpophalangeal (MP) joints underwent the first OA changes until the sixth decade, when the row of distal interphalangeal (DIP) joints became most affected. Cluster analysis showed that symmetry was the most common pattern of interrelationship between rows of joints. The best-fitting and most parsimonious model of age-related pattern of hand OA was the polynomial two-interval linear model. It showed a higher rate of OA development during the relatively young ages, 32-34 years than later on. We found statistically significant differences between sexes only for the DIP (P = 0.019) and PIP (P = 0.011) rows of joints. Handedness had no influence on hand OA development.

Subchondral bone changes in hand and knee osteoarthritis detected by radiography

OBJECTIVE

To describe the changes in subchondral bone that occur with the onset and progression of osteoarthritis (OA) from macroradiographic assessment of patient's hand and knee joints.

DESIGN

The high magnification and spatial resolution of macroradiography permits detailed anatomical changes to be detected in OA joints. Data on the subchondral cortical and cancellous bone, recorded from both cross-sectional and longitudinal studies of hand and knee OA, are described and discussed with reference to recent findings on the altered biomechanical properties of OA bone.

RESULTS

In OA joints, both subchondral cortical plate and subjacent horizontal trabeculae increase in thickness early, prior to joint space narrowing (JSN). With progression, cortical plate sclerosis increased in 60% of OA hands and did not change in knee OA until JSN <1.5mm in the medial diseased compartment. In knee OA, trabeculae, at sites of tibial subchondral sclerosis, increased in number and extent, changes that overlay a subarticular region that was osteoporotic. With cartilage loss, the articular surfaces in some knees appeared corrugated, and later, with bone-on-bone, the surfaces became flattened and deformed.

CONCLUSIONS

The weaker than normal bone within thickened subchondral cortical plate and trabeculae of OA joints leads, in advanced OA, to deformation of the articular surfaces and absorption of local stresses producing an effect similar to stress-shielding. This effect, it is suggested, results in the subarticular osteoporosis.

Effect of a topical herbal cream on osteoarthritis of the hand and knee: a pilot study

OBJECTIVE

To compare the efficacy of an herbal ointment to a sham ointment for relieving pain and stiffness associated with osteoarthritis of the hand and knee.

METHOD

Single-blind, randomized controlled clinical trial conducted in 3 chiropractic medicine practices. Subjects were solicited from patients attending the 3 centers. Selection of subjects with osteoarthritis of the hand or knee was based on the criteria developed by the American College of Rheumatology. Subjects were randomized to an active (n = 17) or a sham (n = 19) group. Subjects applied the herbal ointment to the affected joint(s) for 42 consecutive days and recorded level of pain and stiffness daily on visual analog scales.

RESULTS

Thirty subjects completed the study (15 active and 15 sham). Significant differences in pain (P = 0.003) and stiffness (P = 0.0008) were found between the first 21 days of application and the last 21 days of application for the experimental group but not for the sham group. Gain scores between the experimental and sham groups were significant for pain (P = 0.026) and stiffness (P = 0.042).

CONCLUSION

An herbal ointment showed significant improvement in pain and stiffness for patients with hand and knee osteoarthritis who applied the ointment to the affected joint(s) for 42 consecutive days.

Interrelationship between bone aging traits and basic anthropometric characteristics

Using plain hand radiographs, the age dependence of various bone-aging traits (bone mineral density [BMD], cortical index [CI], osteoarthritis [OA], and osseographic [OSS] scores) was evaluated to test whether the correlation among these traits is an individual- or population-based phenomenon. In addition, the effect of anthropometric features on variation of bone-aging traits was estimated. The study included 1,295 individuals from Chuvasha, Russia, 18 to 89 years. BMD was measured from the compact compartment of the middle and distal phalanges of both 3(rd) fingers. The CI of the II-IV metacarpal bones and II-IV proximal phalanges was obtained. The development of OA was based on the standard Kellgren and Lawrence grading scheme for 28 hand joints. OSS score, a surrogate measure that takes into account different kinds of bone changes, was also obtained for each individual. Body weight and height, eight skinfold thicknesses on the trunk and extremities, and breadths of the long bones were measured. Sex-based univariate analyses and multivariate statistical analysis showed the following: 1) Age dependence was defined more strongly in "OA-linked" compared to "osteoporosis (OP)-linked" traits; 2) While "OP-linked" bone-aging traits correlated with age differently between sexes, "OA-linked" traits did not; 3) The strong interrelationship between OA-linked and OP-linked traits in both sexes became very weak and statistically insignificant (P > 0.10) after adjustment for age. Thus, OA and OP conditions in the same individual develop independently and probably reflect different underlying physiological mechanisms. 4) Anthropometric characteristics were significantly correlated with bone-aging traits, but correlations were low (r < 0.20). Thus, the contribution of anthropometric characteristics to the rate and pattern of bone aging of the hand was to relatively small.

Comparative analysis of age prediction by markers of bone change in the hand assessed by roentgenography

The major aim of this study was to develop an accurate method of age prediction for a wide range of ages based on the roentgenographic assessment of the hand bones. Such a method may be of particular interest in paleoanthropology and forensic medicine. The present paper provides the results of an analysis of individuals belonging to two ethnically different population samples: 1) Chuvasha (the Russian Federation), 293 males and 254 females, aged 18-91 and 18-86 years, respectively; and 2) Turkmenians (the Republic of Turkmenia), 257 males and 386 females, aged 18-82 and 17-83 years, respectively. The hands of study participants were roentgenographed with standard methodology. For each roentgenogram an equidistant osseographic score (OSS) including the descriptive criteria of bone age was estimated. In addition, an osteoarthritic and an osteoporotic score (OA and OP, respectively) were assigned to each individual. OA was a modification of the Kellgren/Lawrence scale, whereas the OP was locally developed. Results of the multiple logistic regression analysis clearly indicated that OSS is a strong predictor variable of an individual's age, with R reaching 0.93 in Chuvasha and 0.89 in Turkmenians (P < 0.001). The standard errors of estimate were approximately +/-5-7 years and compared favorably with most known methods of age assessment using bones. This study provides an efficient method of age prediction, with acceptable accuracy, and extends the upper limit of prediction to the age of 70 years. An additional finding of interest was the coexistence of OA and OP in the bones of the same hand. The observed correlation between these two conditions reached 0.8 (P < 0.001). Am. J. Hum. Biol. 11:31-43, 1999. Copyright 1999 Wiley-Liss, Inc.

An analysis of 14 molecular markers for monitoring osteoarthritis. Relationship of the markers to clinical end-points

OBJECTIVE

To investigate whether any of 14 serum and urine molecular markers (MMs) used to monitor osteoarthritis (OA) would be associated with particular clinical end-points.

DESIGN

Thirty-nine OA patients were bled and urine collected at five time points: at baseline visit and at visits 1, 3, 6 and 12 months later. Twelve clinical measurements were made and the concentrations of each of 14 MMs were determined. Principal component analysis, stepwise linear regression with backward elimination, and logistic regression were used to determine the correlations between MMs and clinical measures.

RESULTS

Principal component analysis was used to reduce the 12 clinical measurements into three independent clinical clusters: baseline clinical assessments, changes in clinical assessments and signal joint measurements. The 14 MMs were similarly reduced to five MM clusters. Each of the three clinical clusters was correlated with a single but different MM cluster. Baseline clinical assessments were correlated with bone markers typified by hydroxylysyl pyridinoline (HP) crosslinks, swelling of the signal joint was correlated with inflammation markers, especially CRP, and the change in clinical assessments over the 1 year evaluation was correlated with TGFbeta1. There was no correlation between any of the skeletal markers and the clinical measures, a situation which draws attention to the need for a direct assessment of cartilage damage in OA to validate the use of cartilage markers.

CONCLUSIONS

This study demonstrates statistical methodology for analysis of clinical trials using multiple MMs and clinical end-points. The patient numbers are sufficient to test hypotheses of relationships of single MMs such as CRP, TGFbeta1 and HP to clinical measures, but larger clinical trials are needed to validate hypotheses.

Early radiographic features in patients with anterior cruciate ligament rupture

OBJECTIVE

To determine, in a preliminary cross sectional study of patients with anterior cruciate ligament (ACL) ruptured knees, which of the radiographic features-subchondral cortical plate thickness, trabecular sclerosis, and osteophytosis-appears before or in association with changes in joint space width (JSW) as a surrogate for articular cartilage thickness in patients with ruptured knees.

METHODS

19 patients (14 men), mean (95% CI) age 28.7 (23.6 to 33.8) years, had ACL rupture in one knee only, confirmed by arthroscopy. Anterior draw, Lachman's test, and pivot shift tests were performed and x5 posteroanterior macroradiographs of both knees in a standing semiflexed view were taken at a mean (95% CI) time from injury of 34. 3 (26.9 to 41.7) months. In each radiograph, computerised methods were used to measure minimum JSW and fractal signature analysis (FSA) to quantify the vertical and horizontal trabecular organisation, osteophyte area, and the subchondral cortical plate thickness, in the medial and lateral tibial compartments of all knees.

RESULTS

Physical examination confirmed the presence of joint laxity in the injured knees. No statistical difference in either medial or lateral JSW and subchondral cortical plate thickness was detected between ACL ruptured and uninjured knees. FSA showed a significant decrease in fractal dimension for the horizontal trabeculae (size 0.42 mm) in the medial compartment of the ACL ruptured knees compared with the uninjured knees (p<0.01, multivariate analysis of variance). There was an inverse correlation (R -0.74) between the time since knee injury and the difference in FSA values for ACL ruptured and uninjured knees in medial compartment horizontal trabeculae (size 0.4 mm). No significant changes were detected in the lateral compartment. Osteophytes were detected in the medial compartment of nine ACL injured knees.

CONCLUSION

Compared with the uninjured knee, ACL rupture leads to thickening of subchondral horizontal trabeculae (decreased FSA) in the medial tibial compartment of all knees, reaching significance at about four years after injury. Osteophytes were present in the same compartment in 9/19 knees. No changes in JSW and subchondral cortical plate thickness were detected. Whether the bony changes detected in these ACL ruptured knees presage those of early osteoarthritis requires further study.

Current status of imaging procedures in the diagnosis, prognosis and monitoring of osteoarthritis

X-ray, magnetic resonance imaging (MRI) and arthroscopy are the methods most widely used to assess the status of osteoarthritic joints. How do these methods compare? As diagnostic tools, what is the relative sensitivity of X-ray versus MRI, arthroscopy versus MRI and arthroscopy versus X-ray? Which imaging modalities can be used for predicting progression? Scintigraphy and MRI can assess the degree of cellular activity in the tissues of a joint, which may help in prognosis. Are the methods proven and are they reliable? Recommendations for clinical trials in knee osteoarthritis, state it is essential that reproducible radiographs are obtained for reliable assessment of progression. Two radiographic views of the knee have been proposed; which provides the more reliable assessment, the knee in extension or semi-flexed? Compared with standard radiography, does microfocal radiography make a difference to patient numbers required for drug trials?

Pathogenesis and treatment of osteoarthritis

OA represents the final common pathway of a number of pathologic processes. The challenge is to define and classify the subsets of OA to understand the causes and to devise specific therapies. Effective chondroprotective therapies will be most useful when applied to high-risk individuals before the emergence of symptomatic OA. This will be feasible only with an improved understanding of the complex interaction of genes and environment in the OA disease process. Moreover, identifying the heritable bases of this disease will provide insight into the molecular mechanisms of the complex pathway that results in OA. Clinicians who encounter and treat OA patients can look forward to the development of more effective and innovative therapies based on a rapidly improving understanding of OA.

Progression of digital osteoarthritis: a sequential scintigraphic and radiographic study

Hand radiographs and scintigraphy were obtained initially and at the 4-year follow-up in 15 patients with symptomatic osteoarthritis (OA) of distal and/or proximal interphalangeal joints. For each joint, a 0-15 score was obtained for the OA radiographic lesions read blind by the same observer. An abnormal isotope retention over a bone reference area was assessed and quantified. The predictive value of scintigraphy for the OA radiographic progression was confirmed and shown to be improved by a second investigation. During the study period, the percentage of radiographic OA joints increased from 66.3 to 76.6%, but joints showing an abnormal scan decreased from 40 to 22.5%. Progression of the OA radiographic score was closely related to scintigraphic changes. The mean difference between the final and initial OA score was -0.08 in joints with two normal scans (N = 115), +0.73 in joints showing a first abnormal and a second normal scan (N = 94) and +1.8 in joints with two abnormal scans (N = 14) or a scan becoming abnormal (N = 47). An abnormal scan appears to represent a transient event, and this event is associated with a period of progression of digital OA. Potentially, anti-OA therapies that suppress joint isotope retention might slow down OA progression. The magnitude of joint isotope retention was positively correlated with the OA radiographic score established at the same time (R = 0.61 and P < 0.001), but showed no predictive value for progression of the latter.

Correlation between synovial fluid markers of cartilage and bone turnover and scintigraphic scan abnormalities in osteoarthritis of the knee

OBJECTIVE

To test the hypothesis that scintigraphic evidence of bone activity will correlate with biochemical evidence of increased matrix turnover in osteoarthritis (OA).

METHODS

Keratan sulfate epitope (5D4), chondroitin sulfate epitope (3B3), and osteocalcin (OC) were measured in synovial fluid (SF) from 35 patients with knee OA, within 1 month of bone scan.

RESULTS

SF OC levels correlated with 5D4 levels (r = 0.32, P = 0.047) and with abnormalities on scintigraphic scan. Mean OC levels were 47% higher (P = 0.016) in patients with severely abnormal findings on scans compared with levels in patients with mildly abnormal scan findings. No significant association of 5D4 or 3B3 levels and perfusion- or late (bone)-phase scintigraphic abnormalities was found.

CONCLUSION

These data support the hypothesis that there is an association between late-phase bone scan abnormalities and SF biochemical markers of bone turnover in OA.

Quantitative radiography of osteoarthritis

Images

Prediction of the progression of joint space narrowing in osteoarthritis of the knee by bone scintigraphy

OBJECTIVES

To test the hypothesis that bone scintigraphy will predict the outcome of osteoarthritis (OA) of the knee joint.

METHODS

Ninety four patients (65 women, 29 men; mean age 64.2 years) with established OA of one or both knee joints were examined in 1986, when radiographs and bone scan images (early and late phase) were also obtained. The patients were recalled, re-examined, and had further radiographs taken in 1991. Paired entry and outcome radiographs were read by a single observer, blinded to date order and other data. Scan findings and other entry variables were related to outcome. Progression of OA of the knee was defined as an operation on the knee or a decrease in the tibiofemoral joint space of 2 mm or more.

RESULTS

Over the five year study period 10 patients died and nine were lost to follow up. Fifteen had an operation on one or both knees (22 knees). Of the remaining 120 knees (60 patients) analysed radiographically, 14 (12%) had progressed in the manner defined. Of 32 knees with severe scan abnormalities, 28 (88%) showed progression, whereas none of the 55 knees with no scan abnormality at entry progressed. The strong negative predictive power of scintigraphy could not be accounted for by disease severity or any combination of entry variables. Pain severity predicted a subsequent operation, but age, sex, symptom duration, and obesity had no predictive value.

CONCLUSIONS

Scintigraphy predicts subsequent loss of joint space in patients with established OA of the knee joint. This is the first description of a powerful predictor of change in this disease. The finding suggests that the activity of the subchondral bone may determine loss of cartilage.