Decrease In Joint Space Width Research Articles

Postoperative Valgus Deformity and Progression of Ostheoarthritis in Non-Displaced Femoral Neck Fractures.

Nondisplaced femoral neck fractures have traditionally been treated with in situ fixation. However, poor surgical and clinical outcomes have been reported for fractures with valgus deformity >15°, and the reduction of valgus impaction has recently been emphasized. In addition, early degenerative osteoarthritis can be caused by cam-type femoroacetabular impingement after healing of femoral neck fractures. This study was designed with the objective of confirming the difference in progression of radiographic osteoarthritis according to the severity of the valgus deformity. Patients who underwent internal fixation using multiple cannulateld screws for management of nondisplaced femoral neck fractures were divided into two groups: high valgus group (postoperative valgus angle ≥15°) and low valgus group (postoperative valgus angle <15°). Evaluation of demographic data and changes in the joint space width from the immediate postoperative period to the latest follow-up was performed. A significant decrease in joint space width in both hip joints was observed in the high valgus group when compared with the low valgus group, including cases with an initial valgus angle less than 15° and those corrected to less than 15° of valgus by reduction. No complications requiring surgical treatment were observed in either group; however, two cases of avascular necrosis, one in each group, which developed in the low valgus group after reduction of the fracture, were followed for observation. Performing in situ fixation in cases involving a valgus deformity ≥15° in non-displaced femoral neck fractures may cause accelerated narrowing of the hip joint space.

Femoroacetabular Impingement and the Effect of Osteochondroplasty on Hip Osteoarthritis Prevention: The Pandora's Box Opening Process.

This study was conducted to assess the effect of osteochondroplasty on osteoarthritis (OA) prevention, comparing radiological evolution between identical hips from the same patient who had undergone unilateral surgery. We retrospectively reviewed radiological evolution between hips with similar shape from the same patient who had undergone unilateral surgery. In all, 56 FAI patients (112 hips) with a mean age of 42.18 ± 9.16 years and had undergone unilateral arthroscopy treatment have been included. Four independent researchers measured Wiberg, Acetabular and Alpha angles, Extrusion index, and Tönnis classification preoperatively to verify that operated and non-operated hips had the same shape. OA evolution was assessed by joint space width (JSW) in 3 different articular points and Tönnis classification. No preoperative anatomical differences were present between groups (P > 0.05). At the end of follow-up (31.9 months), a decrease of JSW in the 3 points measured was found in OP hips (OP vs. N-OP; P < 0.01). These results were correlated with changes in the proportion of patients who progressed to grade III in Tönnis classification (from 1.3% preoperative to 23.2% at the end of follow-up). Osteochondroplasty and labrum procedures were not associated with OA prevention. The OP hips showed a faster OA degeneration, which was not seen in the N-OP. These results will encourage hip surgeons to perform further investigations to avoid the "Pandora's Box Opening Process."

Increased Joint Space Narrowing After Arthroscopic Partial Meniscectomy: Data From the Osteoarthritis Initiative

Background: Arthroscopic partial meniscectomy (APM) is widely performed and remains an important therapeutic option for patients with a meniscal tear. However, it is debated whether or not APM accelerates the progression of osteoarthritis (OA) in the long term. Purpose/Hypothesis: The purpose was to compare the progression of OA measured by the change in tibiofemoral joint space width (JSW)—a quantitative measure of OA radiographic severity—across 3 groups with a midterm follow-up: (1) patients undergoing APM; (2) those with a meniscal tear treated nonoperatively; and (3) those without a tear. We hypothesized that the reduction in JSW would be greatest in patients undergoing APM and least in those patients without a tear. Study Design: Cohort study; Level of evidence, 3. Methods: Using the Osteoarthritis Initiative cohort, a total of 144 patients were identified that underwent APM with at least 12 months of follow up and without previous knee surgery. Those with a meniscal tear who did not have APM (n = 144) and those without a tear (n = 144) were matched to patients who had APM by sex, age, Kellgren-Lawrence (KL) grade, and follow up time. Participants underwent magnetic resonance imaging at baseline. Knee radiographs to assess JSW were collected annually or biannually. The change in minimum medial compartment JSW was calculated using a validated automated method. A piecewise linear mixed effects model was constructed to examine the relationship between JSW decline over time and treatment group—adjusting for age, body mass index, smoking status, KL grade, and baseline JSW. Results: All groups had comparable baseline JSW—ranging from 4.33 mm to 4.38 mm. The APM group had a rate of JSW decline of −0.083 mm/mo in the first 12 months and −0.014 mm/mo between 12 and 72 months. The rate of JSW decline in the APM group was approximately 27 times greater in the first 12 months than that in the nonsurgical group (−0.003 mm/mo) and 5 times greater than that in the no tear group (−0.015 mm/mo); however, there was no significant difference between groups for 12 to 72 months (nonsurgical group: −0.009 mm/mo; no tear group: −0.010 mm/mo). The adjusted JSW in the APM group was 4.38 mm at baseline and decreased to 2.57 mm at 72 months; the JSW in the nonsurgical group declined from 4.31 mm to 3.73 mm, and in the no tear group it declined from 4.33 mm to 3.54 mm. There was a statistically significant difference in JSW change between baseline and 72 months for the APM group compared with the other groups (P < .001), but not between the nonsurgical and no tear groups (P = .12). Conclusion: In the first postoperative year, APM results in a faster rate of joint space narrowing compared with knees undergoing nonsurgical management of meniscal tears. Thereafter, there are comparable rates of OA progression regardless of the chosen management. APM results in a persistent decrease in JSW over at least 72 months. An untreated meniscal tear does not contribute to radiographic progression—assessed by JSW—as compared with an intact meniscus.

Long-term Outcomes of Meniscal Allograft Transplantation With and Without Extrusion: Mean 12.3-Year Follow-up Study

Background: Meniscal allograft transplantation (MAT) is a widely performed surgical technique used to reconstruct meniscal deficiencies after meniscectomy. However, the long-term effects of extrusion on clinical and radiologic outcomes are unclear. Hypothesis: In long-term follow-up, extrusion after MAT would show poorer outcomes than nonextrusion and would lead to faster progression of arthritic changes. Study Design: Cohort study; Level of evidence, 3. Methods: Forty-five MAT cases (lateral, n = 36; medial meniscal, n = 9) with a minimum 8-year follow-up period were selected. The mean follow-up period was 12.3 years (range, 8.0-19.6 years). Data were collected on patients’ sex, age, surgical side, and mechanical axis deviation. Patients were categorized into 2 groups: extrusion (≥3 mm) and nonextrusion (<3 mm). Categories were based on extrusion length measured via magnetic resonance imaging taken 1 year after surgery. Joint space width (JSW) on the affected and contralateral sides was measured on bilateral weightbearing posterior-anterior radiographs at 45° of flexion at 3 time points (preoperative, 4-6 years postoperative, and >8 years postoperative). Differences of the measured and relative JSW values between the groups and differences at different time points were analyzed. The Lysholm score was used to evaluate clinical function. Results: Mean ± SD extrusion was 3.07 ± 0.82 mm. The extrusion and nonextrusion groups were composed of 19 (42.2%) and 26 (57.8%) patients, respectively. Analysis of JSW showed a difference in relative JSW between the groups at >8 years (P = .017). At the point of transition from 4 to 6 years to >8 years, the differences in absolute JSW values were −1.25 ± 0.78 mm (extrusion group) and −0.58 ± 0.66 mm (nonextrusion group; P < .001). Relative JSW values also differed between groups (extrusion group, −0.22 ± 0.13; nonextrusion group, −0.04 ± 0.18; P < .001). No differences were observed in the Lysholm scores between the groups at each time point. Conclusion: Long-term follow-up after MAT revealed a greater decrease in JSW in the extrusion group than in the nonextrusion group. However, no significant differences in clinical outcomes were observed.

Intra-articular corticosteroids and the risk of knee osteoarthritis progression: results from the Osteoarthritis Initiative

A recent randomized clinical trial reported that repeated intra-articular corticosteroids (IACs) were associated with a greater cartilage loss. This study aimed to examine the relation of IACs to knee radiographic osteoarthritis (ROA) progression in a real-world setting. A cohort that initiated IACs and a comparison cohort without IACs from participants with mild to moderate knee ROA in the Osteoarthritis Initiative (OAI) were assembled (from 0-month to 48-month). Two measures of knee ROA progression were assessed during the follow-up period: (1) an increase in Kellgren and Lawrence (KL) grade by ≥1 grade or having a knee replacement (i.e., KL grade worsening); and (2) a decrease in joint space width (JSW) by ≥0.7mm or having a knee replacement (i.e., JSW worsening). The associations of IACs initiation using a propensity-score matched cohort study and continuous IACs using marginal structural models with the risk of knee ROA progression were examined. Among 684 propensity-score matched participants at baseline (148 IACs initiators, 536 comparators), 65 knees (21.7/100 person-years) in the IACs initiation cohort and 90 knees (7.1/100 person-years) in the comparison cohort experienced KL worsening. The hazard ratios (HRs) of KL worsening from IACs initiation and continuous IACs were 3.02 (95% confidence interval [CI], 2.19-4.16) and 4.67 (95% CI, 2.92-7.47), respectively. The corresponding HRs of JSW worsening were 2.93 (95% CI, 2.13-4.02) and 3.26 (95% CI, 1.78-5.96), respectively. All HRs for continuous use of IACs were further away from the null. IACs, especially continuous IACs, may be associated with an increased risk of knee ROA progression.

Radiographic evaluation of knee joint space width using fixed flexion view in knees of Indian adults

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; The objective of this study is to evaluate the tibiofemoral joint space width in the medial and lateral compartments of the knee using digital radiograph. The measurement of knee joint space width (JSW), in between the femur and the tibia is a way of evaluating the tibio-femoral cartilage thickness. This study is aimed at establishing normal references of joint space width for use in diagnosis and follows up of knee cartilage diseases.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; This study is prospective and carried on 50 subjects at SAMC &amp;amp; PGI, Indore, M.P. One patient refused to sign the consent and was excluded. All subjects were healthy adults with sedentary lifestyle. All subjects underwent x-ray of bilateral knee joints. The joint space width of both medial and lateral compartments of each knee was measured using the scale in the computerized software.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; The average age in the study group was 44.59 years with male preponderance.The mean left medial and lateral joint space width was 5.34 mm±1.26 mm and 5.21 mm±1.04 mm and on right side was 5.26±1.11 mm and 5.57±1.57 mm, respectively. No statistically significant difference was found between right and left knee joint space width compartments.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; The values obtained after observing the radiographic references showed no significant gender variation in knee joint space width. But, it is seen that there is a decrease in joint space width with increasing age, which progresses towards osteoarthritis of knee.&lt;/p&gt;

Effects of dietary weight loss with and without exercise on interstitial matrix turnover and tissue inflammation biomarkers in adults with knee osteoarthritis: the Intensive Diet and Exercise for Arthritis trial (IDEA).

To examine the effects of dietary weight loss, with and without exercise, on selected soluble biomarkers in overweight and obese older adults with symptomatic knee osteoarthritis (OA). Blood samples were analyzed from 429 participants in the Intensive Diet and Exercise for Arthritis (IDEA) trial randomized to either an 18 month exercise control group (E), weight loss diet (D), or D+E. C1M, C2M, C3M and CRPM biomarkers and interleukin-6 (IL-6) were quantitated using ELISAs. Radiographic progression was defined as a decrease in joint space width of ≥0.7mm. Statistical modeling of group means and associations used mixed models adjusted for visit, baseline body mass index (BMI), gender, and baseline values of the outcome. Compared to the E control group, C1M was significantly lower in the D and D+E groups at both 6 and 18 months while C3M was significantly lower in D and D+E at 6 months and in D+E at 18 months. C2M did not change in any group. Using data from all groups, change in C1M (P<0.0001), C3M (P<0.0001), as well as CRPM (P=0.0004) from baseline to 18 months was positively associated with change in weight. No marker was associated with change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain or radiographic progression. C3M (P=0.008) and CRPM (P=0.028) were positively associated with change in WOMAC function. Change in IL-6 was positively associated with change in C1M, C3M, and CRPM. Overweight and obese adults with knee OA who lost weight from diet and diet plus exercise reduced serum markers of interstitial matrix turnover and inflammation but not type II collagen degradation.

Association of urinary metabolites with radiographic progression of knee osteoarthritis in overweight and obese adults: an exploratory study

Metabolic factors may contribute to osteoarthritis (OA). This study employed metabolomics analyses to determine if differences in metabolite profiles could distinguish people with knee OA who exhibited radiographic progression. Urine samples obtained at baseline and 18 months from overweight and obese adults in the Intensive Diet and Exercise for Arthritis (IDEA) trial were selected from two subgroups (n=22 each) for metabolomics analysis: a group that exhibited radiographic progression (≥0.7mm decrease in joint space width, JSW) and an age, gender, and body mass index (BMI) matched group who did not progress (≤0.35mm decrease in JSW). Multivariate analysis methods, including orthogonal partial least square discriminate analysis, were used to identify metabolite profiles that separated progressors and non-progressors. Plasma levels of IL-6 and C-reactive protein (CRP) were evaluated as inflammatory markers. Multivariate analysis of the binned metabolomics data distinguished progressors from non-progressors. Library matching revealed that glycolate, hippurate, and trigonelline were among the important metabolites for distinguishing progressors from non-progressors at baseline whereas alanine, N,N-dimethylglycine, glycolate, hippurate, histidine, and trigonelline, were among the metabolites that were important for the discrimination at 18 months. In non-progressors, IL-6 decreased from baseline to 18 months while IL-6 was unchanged in progressors; the change over time in IL-6 was significantly different between groups. These findings support a role for metabolic factors in the progression of knee OA and suggest that measurement of metabolites could be useful to predict progression. Further investigation in a larger sample that would include targeted investigation of specific metabolites is warranted.

Milk Consumption and Progression of Medial Tibiofemoral Knee Osteoarthritis: Data From the Osteoarthritis Initiative

Milk consumption has long been recognized for its important role in bone health, but its role in the progression of knee osteoarthritis (OA) is unclear. We examined the prospective association of milk consumption with radiographic progression of knee OA. In the Osteoarthritis Initiative, 2,148 participants (3,064 knees) with radiographic knee OA and dietary data at baseline were followed up to 12, 24, 36, and 48 months. Milk consumption was assessed with a Block Brief Food Frequency Questionnaire completed at baseline. To evaluate progression of OA, we used quantitative joint space width (JSW) between the medial femur and tibia of the knee based on plain radiographs. The multivariate linear models for repeated measures were used to test the independent association between milk intake and the decrease in JSW over time, while adjusting for baseline disease severity, body mass index, dietary factors, and other potential confounders. We observed a significant dose-response relationship between baseline milk intake and adjusted mean decrease of JSW in women (P = 0.014 for trend). With increasing levels of milk intake (none, ≤3, 4-6, and ≥7 glasses/week), the mean decreases of JSW were 0.38 mm, 0.29 mm, 0.29 mm, and 0.26 mm, respectively. In men, we observed no significant association between milk consumption and the decreases of JSW. Our results suggest that frequent milk consumption may be associated with reduced OA progression in women. Replication of these novel findings in other prospective studies demonstrating the increase in milk consumption leads to delay in knee OA progression are needed.

Alendronate treatment for hip osteoarthritis: prospective randomized 2-year trial

We examined the clinical efficacy of alendronate treatment for hip osteoarthritis using multiple outcome measures. Fifty patients with symptomatic hip osteoarthritis were enrolled in this prospective trial. The patients were randomly assigned to an alendronate group (35 mg/week alendronate and 600 mg/day calcium lactate) or a control group (600 mg/day calcium lactate) for 2 years. The groups were compared with regard to the following five parameters. The primary outcome measures are the following: (1) the Western Ontario and McMaster Universities (WOMAC) osteoarthritis pain score and the visual analog score (VAS). The secondary outcome measures are the following: (2) joint space width (JSW) measured on radiographs using a semiautomatic computer software, (3) the biochemical markers urinary N-telopeptide of type I collagen (NTX-I) and C-terminal cross-linking telopeptide of type II collagen (CTX-II), (4) dual-energy X-ray absorptiometry of the hip and lumbar spine, and (5) bone marrow edema on magnetic resonance images. The alendronate group showed pain improvement trends in VAS and WOMAC scores, whereas the control group showed worsening of pain. The alendronate group showed significant improvement in WOMAC pain scores after 12 months (p = 0.031) but no significant prevention of structural osteoarthritis progression, defined as a decrease in JSW >0.30 mm or conversion to total hip arthroplasty. There was significantly larger decrease in the biochemical markers and significantly increased bone density in the alendronate group. Alendronate treatment by standard dose for osteoporosis showed clinical efficacy for decreasing pain but failed to show preventive effects for structural progression of hip osteoarthritis.

Digital radiographic measurement of normal knee joint space in adults at Kano, Nigeria

ObjectiveThe measurement of knee joint space width (JSW), between the distal femur and the proximal tibia is an indirect way of measuring the tibio-femoral cartilage thickness, which is considered a valuable parameter, in assessing knee cartilage disease. This study is aimed at establishing normal references of JSW for use in diagnosis and follow up of knee cartilage diseases. MethodsThis prospective study was conducted on 30° fixed-flexion erect knee computed radiographs of 160 adults. The JSW of both medial and lateral compartments of each knee was measured using in-built electronic calipers. ResultsThe mean right medial and lateral JSW measured 4.74mm±0.75 and 5.63mm±0.86, respectively. The mean left medial and lateral JSW measured 4.74mm±0.76 and 5.66mm±0.87. No statistically significant difference was found between right and left knee JSW compartments. DiscussionsThe radiographic reference values of the knee JSW were obtained, showing no significant gender variation in knee JSW. However, there is a decrease in JSW with increasing age.

Comparison of cartilage thickness with radiologic grade of knee osteoarthritis

To compare joint space width (JSW) measurements obtained from magnetic resonance imaging (MRI) with a semi-automated computer algorithm to the Kellgren and Lawrence grading of osteoarthritis (OA). Three hundred and six patients (234 female, 72 male) with a mean age of 56.7 years (range 31-81 years) underwent MRI of their knees with a fast oblique spiral spoiled gradient (SPGR) sequence. A board-certified musculoskeletal radiologist graded the OA of all the patients in accordance with the Kellgren and Lawrence OA scale. A previously validated computer algorithm was used to determine the minimum JSW for both the tibiofemoral joint and the patellofemoral joint. An analysis of variance (ANOVA) with the Student-Newman-Kuels post-hoc test was used to determine if there were differences in JSW as a function of OA grade. The radiologic grade of OA was inversely associated with the JSW. In the medial compartment the JSW did not change significantly between grade 1 and grade 2, but there was a significant decrease in JSW between grade 0 (normal) and grade 1 and for each OA grade above grade 2. In the lateral compartment no statistical differences were found till grade 2, while grade 3 was found to be statistically different from the previous one. The number of patients with a grade 4 patellofemoral OA was too low for the statistical significance to be assessed. In the patellofemoral joint the JSW did not change significantly until grade 2, while a statistically significant reduction was found for both grade 3 and grade 4. This study showed that an inverse non-linear relationship exists between radiologic grade and JSW. The relationship differs for the tibiofemoral and the patellofemoral joint.

Role of radiography in predicting progression of osteoarthritis of the hip: prospective cohort study

Objectives To investigate which variables identify people at high risk of progression of osteoarthritis of the hip.Design Population based cohort study.Setting Ommoord district in Rotterdam, Netherlands.Participants 1904 men and women...

Acetabular dysplasia predicts incident osteoarthritis of the hip: The Rotterdam study

To investigate the association between acetabular dysplasia and the incidence of radiographic osteoarthritis (OA) of the hip in a population-based sample of elderly subjects. Radiographs of the hip at baseline and at followup (mean followup time 6.6 years) were evaluated in 835 men and women (age >or=55 years) from the Rotterdam Study. Subjects with a baseline Kellgren/Lawrence grade of 0 or 1 in both hips were included in the study. Incident radiographic OA of the hip was defined as a decrease of joint space width of the hip (>or=1.0 mm) at followup. Acetabular dysplasia was assessed using the center-edge angle and the acetabular depth. The association between acetabular dysplasia and incident radiographic hip OA was assessed by calculating odds ratios using multivariate regression analysis. In this study population with a mean +/- SD age of 65.6 +/- 6.5 years, 9.3% developed incident radiographic hip OA. Subjects with acetabular dysplasia (center-edge angle <25 degrees ) had a 4.3-fold increased risk for incident radiographic OA of the hip (95% confidence interval 2.2-8.7) compared with subjects without acetabular dysplasia. These associations were independent of known determinants of hip OA such as age, sex, and body mass index (BMI), but tended to be enhanced by female sex, heavy mechanical load, and low BMI. In a study population age >or=55 years, acetabular dysplasia is still a strong independent determinant of incident radiographic hip OA.

A new marker for osteoarthritis: cross-sectional and longitudinal approach.

To investigate the association between urinary concentrations of C-telopeptide fragments of type II collagen (CTX-II) and the prevalence and progression of radiographic osteoarthritis (OA) of the knee and hip. The study population consisted of a sample of 1,235 men and women ages > or =55 years who were enrolled in the Rotterdam Study (a population-based cohort study) and who were followed up for a mean of 6.6 years. Prevalent radiographic OA was defined as a Kellgren/Lawrence score > or =2; progression of radiographic OA was defined as a decrease in joint space width. Subjects with a CTX-II level in the highest quartile had a 4.2-fold increased risk of having radiographic OA of the knee (95% confidence interval [95% CI] 2.5-7.0) and of the hip (95% CI 2.2-7.8) compared with subjects with a CTX-II level in the lowest quartile. We observed a substantially stronger association between CTX-II levels and radiographic OA for subjects with hip pain (odds ratio [OR] 20.4, 95% CI 2.3-185.2) than for those without hip pain (OR 3.0, 95% CI 1.5-6.0). Subjects with a CTX-II level in the highest quartile had a 6.0-fold increased risk for progression of radiographic OA at the knee (95% CI 1.2-30.8) and an 8.4-fold increased risk for progression of radiographic OA at the hip (95% CI 1.0-72.9). All of these associations were found to be independent of known risk factors for OA, such as age, sex, and body mass index. This study shows that CTX-II is associated with both the prevalence and the progression of radiographic OA at the knee and hip. Importantly, this association is independent of known clinical risk factors for OA and seems stronger in subjects with joint pain.

Knee adduction moment, serum hyaluronan level, and disease severity in medial tibiofemoral osteoarthritis.

The adduction moment at the knee during gait is the primary determinant of medial-to-lateral load distribution. If the adduction moment contributes to progression of osteoarthritis (OA), then patients with advanced medial tibiofemoral OA should have higher adduction moments. The present study was undertaken to investigate the hypothesis that the adduction moment normalized for weight and height is associated with medial tibiofemoral OA disease severity after controlling for age, sex, and pain level, and to examine the correlation of serum hyaluronan (HA) level with disease severity and with the adduction moment in a subset of patients. Fifty-four patients with medial tibiofemoral OA underwent gait analysis and radiographic evaluation. Disease severity was assessed using the Kellgren-Lawrence (K-L) grade and medial joint space width. In a subset of 23 patients with available sera, HA was quantified by sandwich enzyme-linked immunosorbent assay. Pearson correlations, a random effects model, and multivariate regression models were used. The adduction moment correlated with the K-L grade in the left and right knees (r = 0.68 and r = 0.60, respectively), and with joint space width in the left and right knees (r = -0.45 and r = -0.47, respectively). The relationship persisted after controlling for age, sex, and severity of pain. The partial correlation between K-L grade and adduction moment was 0.71 in the left knees and 0.61 in the right knees. For every 1.0-unit increase in adduction moment, there was a 0.63-mm decrease in joint space width. In the subset of patients in whom serum HA levels were measured, HA levels correlated with medial joint space width (r = -0.55), but not with the adduction moment. There is a significant relationship between the adduction moment and OA disease severity. Serum HA levels correlate with joint space width but not with the adduction moment. Longitudinal studies will be necessary to determine the contribution of the adduction moment, and its contribution in conjunction with metabolic markers, to progression of medial tibiofemoral OA.

The effects of position on the radiographic joint space in osteoarthritis of the hip

The aim of the study was to assess whether radiographic hip joint space thickness was changed by weight-bearing (WB) compared with non weight-bearing (NWB) position, and to evaluate whether radiographs centered on the hip were more sensitive than pelvic X-rays to detect such a change. Anteroposterior radiographs of the pelvis were made in 30 patients with hip osteoarthritis OA (46 OA and 11 normal hips). Osteoarthritic, as well as contralateral normal hips were analyzed. Radiographs centered on OA hip were performed in 28 other patients. X-rays were made in WB and NWB positions using a standardized radiological procedure. Measurements of mean joint space width (MeanJSW) maximum joint space narrowing (MaxJSN) and joint space surface area (JSA), were made using a computerized image analysis system. The joint space width was unaffected by WB in normal joints but decreased with WB in OA joints. The decrease was significant only when considering MaxJSN in patients with a joint space thickness smaller than 2.5mm. The difference between WB and NWB was larger in radiographs centered on the hip than on pelvic X-rays. MeanJSW and JSA were found to be less sensitive than MaxJSN. The decrease of joint space width was inversely correlated with joint space size in WB. These results suggest that WB radiographs of the hip should be used in preference to NWB in studies of hip OA.