Yttrium-90 radiation synovectomy in knee osteoarthritis:a prospective assessment at 6 and 12 monthsDimitrios Chatzopoulosa, Efstratios Moralidisc, Pavlos Markoudand Vassilios Makrisb
Objective To assess the outcome of yttrium-90 radiation
(P = 0.850). The probability of a favourable therapeutic
synovectomy at 6 and 12 months in patients with
result was inversely related to the severity of radiographic
knee osteoarthritis unresponsive to systematic or local
Conclusion Yttrium-90 synovectomy exerts a beneficial
Methods Consecutive patients with osteoarthritic knee
therapeutic effect in a substantial proportion of patients
pain resistant to conventional therapy and submitted to
with osteoarthritic knee pain and synovial inflammation,
intraarticular yttrium-90 treatment because of synovial
inadequately controlled by pharmacotherapy. Clinical
inflammation, as demonstrated by early-phase bone
improvement is inversely related to radiographic knee
scintigraphy, were prospectively evaluated at 6 and/or
12 months. The assessment of the outcome of treatment
Kluwer Health | Lippincott Williams & Wilkins.
was based on self-reporting of relief of knee pain limitingdaily activities, measured as percentage reduction of the
Nuclear Medicine Communications 2009, 30:472–479
pretherapeutic joint discomfort with a Visual Analogue Scale. Resting and nocturnal pain also were considered, together
Keywords: knee pain, osteoarthritis, radiation synovectomy, synovitis,
with knee flexibility and ultrasonographic changes.
aDepartment of Nuclear Medicine, b3rd Department of Orthopaedics, Aristotle
Results Among a total of 97 patients, a Z 50% Visual
University, Papageorgiou Hospital, cDepartment of Nuclear Medicine, Aristotle
Analogue Scale pain palliation was experienced by 64 of
University, AHEPA Hospital, Thessaloniki and dDepartment of Medical Physics,
90 (71.1%) patients at 6 months and 50 of 69 (72.5%) at
Health Care Unit Management, Edessa, Greece
12 months (P = 0.992). Moreover, nocturnal and resting pain
Correspondence to Dr Efstratios Moralidis, PhD, Department of Nuclear
alleviation, gain in knee flexibility and regression of large
Medicine, AHEPA University Hospital, 1 Stilp. Kyriakidi Street,
joint effusions and Baker’s cysts were observed in
considerable proportions. In the evaluation of the outcome
Tel: + 30 2310 994688; fax: + 30 2313 016969;e-mail: [email protected]; [email protected]
of treatment in 62 patients with serial assessments using
a composite criterion, 42 (67.7%) versus 40 (64.5%) had
Received 1 December 2007 Revised 12 March 2008
a satisfactory response at 6 and 12 months, respectively
in the affected joint are frequently demanded, which
Osteoarthritis of the knee is a common form of arthritis
may afford some patients a modest and short-lived pal-
in synovial joints, is characterized by progressive loss of
liation of pain [8,9]. On the grounds of the inflammatory
hyaline cartilage and periarticular bone remodeling and
component of osteoarthritis, intraarticular treatment with
constitutes a major medical concern in terms of pain,
b-emitting radioisotopes (radiation synovectomy) would
disability and handicap in ageing populations [1–3].
offer a therapeutic option when other nonsurgical
Synovial membrane inflammation may play a critical role
in disease process and it is likely that synovitis is presentin most patients with symptomatic osteoarthritis, which
The most extensive experience in radiation synovectomy
contributes in the development of pain, limitation of
of the knee joint has been obtained with yttrium-90
movement, joint swelling and effusion [1,3–7].
[10,11]. However, conflicting results have been reportedin knee osteoarthritis with this form of treatment
The management of knee osteoarthritis aims at pain
[12–18]. Earlier reports usually included limited numbers
control, functional improvement and prevention or
of patients [12–15], insufficient data were provided as
retardation of its progression [8]. Despite systemic
often knee osteoarthritis was examined as part of a
pharmacotherapy with analgesics and anti-inflammatory
general evaluation of 90Y treatment [14,16,17], dissimilar
drugs, intraarticular corticoid or hyaluronic acid injections
criteria for patient selection and clinical improvement
c 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
90Y synovectomy in knee osteoarthritis Chatzopoulos et al. 473
were used and success rates varied over a wide range and
effort to limit subjectivity in self-reporting pain, before
at different follow-up intervals. Moreover, evidence of
grading knee discomfort, patients were interrogated in
synovitis with an early-phase bone scan was not always
a standardized manner including questions regarding
pursued [12,15,17,18], whereas ultrasonographic findings
the quality of life and the degree of handicap during daily
after treatment have not been reported before.
activities, such as walking, climbing stairs, standing up,lifting weights or picking up things from the ground. The
Owing to modest results from previous publications,
duration of symptoms was estimated from the time point
radiation synovectomy has been relatively rarely used
patients first asked for medical attention. Resting or
in knee osteoarthritis [11]. Wider acceptance of intraarti-
nocturnal pain were used as surrogate markers of disease
cular 90Y therapy in this disease would be substantiated
activity and their presence or absence at baseline
by stronger evidence in favour of this treatment. There-
examination and after treatment was recorded according
fore, this study was conducted to assess the safety and
to patients’ statement on a dichotomous scale (‘absent’ or
the overall efficacy at 6 and 12 months of 90Y radiation
‘present’). The range of motion of the affected knees
synovectomy in the treatment of knee osteoarthritis and
was employed as an objective indicator of disease and
also to investigate for predictors of response.
measured from full extension to maximum flexion using agoniometer. A limitation in knee flexibility
(maximum expected 1301) was categorized as range of
motion impairment and an increase Z 151 between the
baseline and the posttreatment assessment was classified
synovectomy for knee osteoarthritis over an 18-monthperiod were asked to attend our outpatient clinic at 6 and12 months after the treatment for a prospective follow-up
Patients were submitted to real-time ultrasonography
evaluation. Some of those patients did not attend the
for the evaluation of knees before and after 90Y treat-
planned posttreatment appointments regularly and other
ment, concerning joint effusions and Baker’s cysts. The
returned for reassessment between the scheduled visit
presence and amount of a joint effusion was assessed from
dates or were lost to follow-up. Travelling distance and
scans through the suprapatellar recess and measurement
further management in private practice were the main
of its maximum anteroposterior width [22]. Knee joint
reasons for incomplete outcome data. Among all patients
effusion was classified as large when this dimension was
having undergone 90Y synovectomy during the study
greater than 5 mm and in follow-up assessments,
period, those assessed in our clinic at 6 or 12 months were
a measurement equal to or less than this cut-off point
enrolled in the study, whereas patients with inadequate
was accepted as large effusion regression. Moreover, the
documentation of the outcome of treatment at the
popliteal region was examined for the presence of a
defined time points were disregarded.
Baker’s cyst and its longest diameter was measured. Allultrasonographic acquisitions were performed by a trained
In all patients presenting with knee joint complaints and
and experienced physician. Measurements were taken in
a diagnosis of osteoarthritis, the baseline assessment
duplicate and the mean value was entered in analysis.
included a careful review of medical records and relevant
Synovial membrane thickness was not considered herein,
blood tests, a knee orientated history, physical examina-
as in our experience inflammatory hypertrophy of the
tion, ultrasonography, plain radiography and early-phase
synovium commonly is markedly asymmetrical and, apart
bone scintigraphy. This array of examinations conforms to
from a visual impression, measurements are impractical.
standard evaluation of patients assessed for radiationsynovectomy and in our facility it is typically carried out
At baseline evaluation, participants underwent weight-
within the day of a patient’s appointment or on the next
bearing posteroanterior and lateral radiography of the
day [19,20]. It was ensured that no patient enrolled had
knees and the severity of the disease was classified
a history of knee joint injury or surgery, knee disorders
according to the standard radiological Kellgren–Lawrence
secondary to infection or metabolic abnormalities or
scale for osteoarthritis [23]: 0, no signs of osteoarthritis; 1,
recognized familial disease. The diagnosis of knee
minute osteophytes of doubtful importance; 2, definite
osteoarthritis was independently confirmed, using widely
osteophytes but preserved joint space; 3, definite osteo-
phytes and moderate narrowing of joint space; 4, greatlyimpaired joint space and sclerosis of subchondral bone. In
Knee pain palliation after therapy and associated
addition, blood pool images of the knees from an early-
improvement of functional ability was based on patients’
phase bone scan were acquired to assess for elevated
subjective judgement and expressed as percentage
perfusion in the joints, reflecting synovitis. The degree of
reduction of the pretreatment discomfort, using a Visual
inflammation in the affected joint was assessed visually
Analogue Scale (VAS) with endpoint markings ‘0 (no
and categorized as ‘mild’ or ‘intense’ (tracer accumulation
relief at all) to 100 (complete pain elimination)’. In an
equal to or more than the adjacent soft tissues,
respectively). Knee radiographs and bone scans were
formula for further paired comparisons. The w2 statistic
interpreted by two experienced independent observers,
and Fischer’s exact test were used for categorical data
comparisons and Bonferoni’s adjustment was applied as
appropriate. Potential predictors of VAS improvementscores were assessed by univariate analysis and subse-
The criteria used to proceed to radiation synovectomy in
quently, variables with a P r 0.20 were entered in
patients with knee osteoarthritis were: (i) knee pain at
stepwise regression analysis. A P value of less than 0.05
stress severe enough to prevent engagement from daily
was required for covariates to be included in the
activities for at least 3 months before the therapeutic
regression equation. Logistic regression analysis was used
procedure, resistant to systematic intake of analgesics,
to assess the independent contribution of factors in the
anti-inflammatory medication and intraarticular cortico-
determination of the radiation synovectomy outcome
steroid injections; (ii) early-phase bone scan findings
with a P r 0.10 required for variables to enter in analysis.
consistent with synovial inflammation. Radionuclide
Statistical significance was accepted for P values less than
treatment was not denied in patients with debilitating
knee pain and advanced radiographic alterations, if theywere unwilling to undergo knee arthroplasty or were
poor candidates for surgery because of significant
There were 109 patients with single 90Y treatment for kneeosteoarthritis during the study period. Twelve patients had
inadequate follow-up data (three with complete loss to
The procedure was carried out under sterile conditions
follow-up, five with a single assessment earlier than 6
with 185 MBq 90Y silicate (Yttriumsilicat, Nycomed
months and four returning for posttreatment evaluation
Amersham, UK) instilled in the joint cavity in combina-
in-between the planned dates). Among the remaining 97
tion with triamcinolone hexacetonide 20 mg to minimize
patients, 62 had serial assessments at 6 and 12 months, 28
reactive synovitis provoked by irradiation [11]. Then, the
were assessed at 6 months only and seven had a single 12-
injected joint was immobilized in extension by an elastic
month assessment. The baseline features of all patients are
knee brace and 90Y bremsstrahlung scintigraphy was
listed in Table 1. Owing to the similarities in the three
obtained to verify homogeneous distribution of the radio-
groups of patients with adequate, prospectively collected,
active material within the joint cavity. Subsequently,
follow-up data, those patients were summed up into
patients were advised to rest and abstain from weight
two groups: a population consisting of 90 patients with a
bearing of the respective knee for at least 3 days after
6-month assessment and a second cohort comprising
the injection and discharged with instructions regarding
69 patients assessed at 12 months (Table 1).
radiation protection and follow-up visits. Early posttreat-ment presentation to the clinic was encouraged, if
During the monitoring period, no patient increased
concomitant medication or was treated with intraarticularagents. Conversely, symptoms modifying drugs were
discontinued after treatment in most cases. However, as
The outcome of radiation synovectomy was evaluated at
some patients continued to receive a drug regimen
6 and 12 months in terms of relief of knee pain limiting
because of disease activity in joints other than the treated
daily activities, alleviation of resting or nocturnal pain and
knee, this information was not included.
also the change in the range of motion. In addition, forthe overall assessment of the response to treatment, these
primary outcome measures were combined in a composite
There was no case with compartmentation of the injected
criterion, which is described below. Ultrasonographic
radioactive material into the joint cavity. A moderately
changes after 90Y treatment were used as secondary out-
increased joint effusion was observed in three patients
come measures. Variables recorded at the baseline assess-
within few days after treatment and arthrocentesis was
ment were analyzed for the determination of factors that
performed to resolve knee discomfort. An allergy occurred
might have influenced responsiveness to treatment.
immediately after one procedure, which respondedpromptly to antihistaminic medication and lasted for
2 days. There were no instances of needle-track or skin
Continuous variables were expressed as mean ± 1 standard
burns or other adverse physical effects detected at
deviation and categorical variables as numbers or propor-
tions. Mann–Whitney rank-sum test was used to comparetwo independent samples of patients and Kruskal–
Wallis statistic was used in the comparison of three or
The outcome of radiation synovectomy, including ultra-
four independent groups of patients, followed by Dunn’s
sonographic changes, is summarized in Table 2.
90Y synovectomy in knee osteoarthritis Chatzopoulos et al. 475
Patients’ characteristics at baseline assessment
At 6 and 12 months Only at 6 months Only at 12 months At other time points or lost
There were no significant differences in the comparison between all study participants assessed at 6 months versus those with an assessment at 12 months. K–L, Kellgren–Lawrence radiographic grade. aComparison of the first four groups of patients.
The outcome of yttrium-90 synovectomy at 6 and 12 months
Univariate and stepwise regression analysis of all study
Other potentially explanatory variables by univariate
participants provided the following models for covariates
analysis (age, degree of tracer accumulation in blood pool
in the prediction of VAS improvement scores (K–L grade,
scintigraphy, presence of a large effusion or a Baker’s cyst)
did not contribute significantly in the prediction of VASimprovement in stepwise regression analysis.
¼ 84:0 À 11:6ÂK ÀL grade ðr ¼ 0:439;
Among patients with serial assessments and impairedrange of motion, those with an improvement in knee
flexibility at 12 months had a VAS improvementscore of 70.8 ± 17.6% and those without 33.3 ± 27.1%
(P = 0.000). At that time point, patients with or withoutnocturnal pain elimination had VAS scores of 61.3 ± 27.4
versus 5.0 ± 7.1%, respectively (P = 0.023) and the values
¼ 90:5 À 15:9ÂK ÀL grade ðr ¼ 0:587;
of those with or without resting pain alleviation were
85.0 ± 10.5 versus 41.7 ± 32.5%, respectively (P = 0.009).
In the formulation of a composite criterion for the over-
a significant decline in VAS improvement scoring between
all assessment of 90Y treatment, an upper threshold of
6 and 12 months (P = 0.020). In this cohort, the diameter
VAS improvement was set at Z 70%, based on the
of Baker’s cysts was longer in patients with a satisfactory
weighted mean of this variable in patients with improved
response at 6 months (19.4 ± 21.6 mm) compared with
surrogate markers, whereas a lower cut-off point was
those without (1.1 ± 2.4 mm, P = 0.048) and the duration
selected at the Z 50% level, a value used extensively in
of symptoms was shorter in patients with a sustained
the past [24]. Thus, knees fulfilling any of the following
outcome (27.0 ± 14.0 months) compared with those with
points were considered to have a satisfactory therapeutic
deterioration (48.0 ± 15.7 months, P = 0.021).
(ii) a VAS improvement score of Z 50% combined with
Finally, it should be added that similar findings were
alleviation of resting or nocturnal pain or improvement
observed in the investigation of characteristics of res-
in the range of motion. Joints without any of the above
ponders and in the analysis according to radiographic
requirements were classified as having an unsatisfactory
grading when the composite criterion was applied in all
In the 62 patients with serial assessments, 42 (67.7%) of
them had a satisfactory therapeutic response at 6 months,
This study assessed the outcome of 90Y radiation
whereas at 12 months 36 had a sustained therapeutic
synovectomy in knee osteoarthritis at 6 and 12 months,
result and six deteriorated. Among the 20 patients with
using primary outcome measures similar to the objectives
an unsatisfactory result of treatment at 6 months, there
of medical management, and is one of the largest pub-
were four cases with an upgraded clinical response at
lished series from a single centre heretofore. The results
12 months. Thus, late assessment included 40 (64.5%)
suggest that this form of therapy represents a safe and
satisfactory responses and 22 unsatisfactory therapeutic
competent treatment option in osteoarthritic knee pain
results (P = 0.850, compared with the 6-month assess-
with scintigraphically established synovial inflammation,
ment). The baseline characteristics of patients separated
inadequately controlled by pharmacotherapy.
into those with and those without a satisfactory responseat 6 and 12 months are presented in Table 3. In logistic
Synovial inflammation and yttrium-90 treatment
regression analysis, a radiographic grade K–L
90Y is a pure b-emitter capable of delivering a thera-
(w2 = 6.737, P = 0.009) and a grade K–L Z 3 (w2 = 19.855,
peutic radiation dose to the synovium with inflammatory
P = 0.000) were the best discriminators of the outcome of
hypertrophy. However, owing to the multifactorial aetiology
treatment at 6 and 12 months, respectively. Moreover, a
of osteoarthritis evolution, ablation of the inflamed synovium
radiographic grade K–L Z 3 (w2 = 8.863, P = 0.003) was
may not be expected to influence significantly the entire
the only independent predictor of a sustained or impro-
pathological process, but it can contain local progression and
ved outcome of treatment over the examined period
lead to an alleviation of pain, functional improvement and
regression of effusion. Moreover, as the degree of inflamma-tion in osteoarthritis may vary from a mild intermittent
An analysis of the outcome of treatment in patients with
irritation to marked synovitis, the response rates to radiation
serial assessments based on the severity of radiographic
synovectomy would depend on the extent of inflammatory
alterations is presented in Table 4. In knee joints with
involvement [11,25–27]. Hence, a pretreatment early-phase
advanced radiographic abnormalities (K–L 3–4), there was
Baseline characteristics of patients with serial assessments grouped according to the outcome of treatment based on the
K–L, Kellgren–Lawrence radiographic grade.
90Y synovectomy in knee osteoarthritis Chatzopoulos et al. 477
The outcome of yttrium-90 synovectomy in knee joints serially assessed, according to the radiographic classification
Z 50% Baker’s cyst diameter reduction, n (%)
Z 50% Baker’s cyst diameter reduction, n (%)
K–L, Kellgren–Lawrence radiographic grade; VAS, Visual Analogue Scale. In paired comparisons: *P < 0.05 in K–L 0–1 versus K–L 3–4; **P < 0.05 in K–L 2 versus K–L 3–4.
Pain is the most prominent and disabling symptom in
A plausible explanation would be that radiographic
knee osteoarthritis, but the assessment of its severity may
alterations incorporate the effect of many factors
present difficulties [21]. It is likely that certain features
influencing the progressive damage of joint architecture.
of pain can be judged more reliably while retaining their
It is also worth noting that the intensity of tracer
clinical usefulness, such as pain at rest and pain that
accumulation in blood pool images could not contribute
disrupts sleep, whereas the impact of pain on functioning
significantly in the prediction of VAS improvement scores
represents another essential part of the assessment [28].
and it could not determine a satisfactory therapeutic
In our study, these issues were taken into account in the
result (Table 3). These findings imply that in osteoar-
assessment of knee pain and also in the implementation
thritic knees with scintigraphically established synovitis,
the degree of inflammation may not influence significantlythe outcome of treatment.
The outcome of treatmentSide effects in 90Y synovectomy were rare, harmless
and easy to manage. On the basis of VAS scoring, the
Repeat ultrasonography at 6 and 12 months showed
probability of a Z 50% alleviation of knee pain limiting
substantial regression of large joint effusions (76.2 vs.
daily activities amounted to 71.1 versus 72.5% at 6 and 12
92.9%, respectively) and elimination of Baker’s cysts
months, respectively, in all participants of the study
(65.5 vs. 78.3%, respectively). The former is a recognized
(Table 2). Moreover, there was a favourable effect in knee
response and an indication for radionuclide therapy
flexibility, while nocturnal pain was almost completely
[12,19]. The prevalence of Baker’s cysts is associated with
eliminated, though the response rate was less good in
synovial inflammation (unpublished data from our institu-
the remission of resting pain. Notably, although there was
tion) and their regression may reflect an effective anti-
a declining trend in the response to treatment between
inflammatory treatment. Interestingly, ultrasonographic
early and late assessment in terms of VAS scoring and
results at 12 months tended to be better than those at
resting pain, no statistically significant difference was
6 months, but this observation was not supported by
attained, indicating that the therapeutic result largely
statistical significance (Tables 2 and 4).
was sustained up to 12 months. Pain palliation andassociated functional improvement were significantly
related to the grade of radiographic alterations, as shown
On the basis of both VAS scoring and the composite
by regression equations (1) and (2).
criterion, patients with no or minimal radiographicabnormalities (K–L 0–1) tended to have a better
The overall outcome of 90Y treatment based on the
response to treatment in comparison to patients with
composite criterion was similar at 6 and 12 months, with
only definite osteophytes on radiographs (K–L 2), but at
67.7 and 64.5% of patients with serial assessments attaining
no statistical significance (Table 4). Conversely, com-
a satisfactory response at those time points, respectively
pared with patients with nonsevere radiographic joint
(Table 3). Radiographic grading was the best predictor of
damage (K–L 0–1 or 2), patients with higher-grade
the clinical outcome and the sole discriminator of a
morphological alterations (K–L 3–4) experienced a lower
degree of pain palliation and functional improvement.
radiographic alterations are severe, radiation treatment is
In addition, those patients gained less in knee flexibility
helpful [18], which is in agreement with our findings.
and also had a decreased probability for a satisfactory or
There are also published data concurring in that the
sustained therapeutic outcome. In this context, VAS
clinical outcome is not influenced by age, sex and the
improvement score decreased significantly from 54.7 to
duration of symptoms, which is consistent with our results
34.4% between 6 and 12 months. However, in that popula-
[15,16]. Finally, an intraarticular 90Y dose of 185 MBq was
tion, alleviation of nocturnal pain and favourable ultrasono-
injected in all previous series, except a single study using
graphic changes were observed in considerable proportions,
222 MBq [12]. Notably, in our study, 57 out of 97 knees
similar to those of patients with less joint damage. Overall,
(59%) had definite osteophytes and also in 30 cases
these findings indicate that radiation synovectomy may be
(31%) joint space was narrowed, but such information
helpful in an appreciable number of osteoarthritic knees
cannot be extracted from earlier work.
with advanced radiographic deformation. In that cohort,increased dimensions of Baker’s cysts at baseline assess-
ment and a short duration of symptoms were associated
Among all patients submitted to radiation synovectomy,
with a beneficial or sustained response, respectively, though
those with inadequate documentation of the outcome
of treatment at the defined time points were excluded. It should be mentioned, however, that consecutive
patients were enrolled and assessed prospectively, while
In literature, no uniform validated system has been used
the reasons for loss to follow-up were not related to the
for the assessment of the clinical efficacy of radiation
outcome of treatment. Moreover, the baseline character-
synovectomy and the selection criteria differ in various
istics were similar between patients with inadequate
studies; thus, comparison with other data is difficult.
outcome data, those with a single follow-up visit and
Furthermore, in virtually all previous reports, only
those with serial assessments (Table 1), whereas the
a fraction of the entire population consisted of patients
response to treatment was trivially affected when the
with knee osteoarthritis, so that their demographic or
latter two groups were summed up (Table 2). These
outcome data usually are impossible to separate. In earlier
publications encompassing knees treated in the indica-tion of osteoarthritis, the improvement rates range from35 to 71% with the outcome evaluated 6–30 months after
It would be preferable for the outcome to rely on
therapy [12–18]. Most previous series were retrospective
explicit measures endorsed by international bodies
[12,13,17], one of them in a multicenter setting [16],
[24]. However, the criteria used in our study reflect our
while there is one follow-up study [14] and another broad
experience and routine practice for many years, the
survey of literature [18]. The assessment of the outcome
rationale in applying them was discussed above, and the
was based on a standardized questionnaire [13,14,16],
conclusions were based on substantially improved scores
patients’ subjective judgement and the status of joint
effusions [12], improvement of pain [17], or a globalopinion from the physician or the patient and further
The efficacy of a therapy ideally is evaluated by a
need for intraarticular steroid injections [15]. There are
controlled randomized trial. It should be added, how-
studies enrolling patients unresponsive to medical
ever, that the progression of osteoarthritis may vary
treatment [14,17], one publication required resistance
and be influenced by a number of factors, so that in this
to intraarticular steroid injections but included a small
situation, the formation of a matched group by randomi-
number of joints previously submitted to arthroscopic
zation is not always likely and the usefulness of a control
synovectomy [12] and other patients underwent radiation
sample would be debatable [29]. Moreover, the continua-
synovectomy according to published guidelines [16] or
tion of an ineffective therapeutic regimen or injections
with no specified criteria [15]. Few investigators provide
of intraarticular placebo, despite evidence of synovial
information on the duration of symptoms [12,15], which
inflammation on bone scintigraphy (which, in turn,
is longer than that of our population. In publications
entails non-negligible radiation exposure), may prevent
reporting on participants’ age, this is comparable to that
the consent of candidates. Nevertheless, although this
of our sample in some studies [14,16,17], but the
study was not powered by a control arm, it retains the
population is younger in other [12,15]. Concordant to
validity of a prospective assessment of the effect of
our methodology, synovitis was proven by blood pool
intraarticular 90Y in a random population of patients
scans in some studies [13,14,16], whereas knee flexibility
with osteoarthritic knee pain and associated synovitis,
was considered in other publications [15,16]. Congruent
refractory to systematic and local pharmacotherapy.
to our results, a better clinical outcome with minimal
In this context, the recorded response rates at 6 and
radiographic changes has been reported previously
12 months (Table 2) support that 90Y treatment provides
[15,18], although there are data disputing this obser-
a substantial therapeutic benefit when conventional
vation [17]. One work supports that even when the
90Y synovectomy in knee osteoarthritis Chatzopoulos et al. 479
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AJNR Am J Neuroradiol 24:463–471, March 2003 Aneurysm Clips: Evaluation of Magnetic Field Interactions and Translational Attraction by Use of “Long-Bore” and “Short-Bore” 3.0-T MR Imaging Systems Frank G. Shellock, Jean A. Tkach, Paul M. Ruggieri,Thomas J. Masaryk, and Peter A. Rasmussen BACKGROUND AND PURPOSE: The use of 3.0-T MR systems is increasing worldwide. We
Using Business Intelligence to Discover New Market OpportunitiesUsing Business Intelligenceto Discover New MarketOpportunitiesJanice FratesCalifornia State University Long BeachMany companies have customers of which theyBusiness Intelligence, Marketing, Competition,are only minimally aware, people who started using agiven product while seeking a solution for an appar-ently unrelated need. Th