Reliability of radiographic assessment in hip and knee osteoarthritis

OBJECTIVE: To evaluate the reproducibility of commonly used radiographic measures in hip and knee OA and to overcome certain limits of existing knowledge on their reliability from previous studies. DESIGN: Three readers evaluated 100 hip joints (50 pelvic X-rays) and 100 antero-posterior and lateral knee films of a hospital-based sample of patients with radiographic OA at two time points 3 months apart. They retrospectively estimated the presence and severity of joint specific individual radiographic features (osteophyte formation and joint space narrowing at different sites, cysts, subchondral sclerosis, bony deformity and chondrocalcinosis) and two different overall scores. Within and between observer reproducibility was calculated by intra-class correlation coefficient. RESULTS: At the hip joint excellent intra- as well as inter-observer reliability for superior joint space narrowing (JSN) and femoral head deformity could be demonstrated, while the assessment of medial JSN, osteophytes and acetabular sclerosis depends on the level of the investigator's experience. At the knee joint, femorotibial and patellofemoral osteophytes showed a high intra- and inter-observer reliability. Grading of JSN is highly reader dependent; rating of subchondral sclerosis and chondrocalcinosis does not seem to be reproducible enough. The overall scores showed an excellent reproducibility both at hip and knee joints. CONCLUSION: A reliable radiographic severity grading of hip and knee OA is possible with the application of global scores and individual features, if joint specific items are selected and readers are trained enough.     

Static knee alignment and its association with radiographic knee osteoarthritis

OBJECTIVES: Although knee alignment is associated with the progression of knee osteoarthritis (OA), it is unclear which features that characterize radiographic OA are related to alignment. The aim of this study was to examine the relationship between static knee joint alignment (measured as a continuous variable) and the radiographic features of knee OA (joint space narrowing and osteophytes). METHODS: One hundred and twenty one adults with symptomatic knee OA were recruited using a combined strategy including referral from specialist centres, arthritis support groups and media advertising. X-rays were performed to classify the severity of disease and to determine static knee alignment. RESULTS: Increasing varus knee alignment was associated with increasing risk of medial compartment joint space narrowing (P < 0.001) and osteophytes (P = 0.005). Increasing valgus knee alignment was associated with an increased risk for lateral compartment joint space narrowing (P < 0.001) and osteophytes (P = 0.002). CONCLUSION: This study has demonstrated that the static knee angle, measured as a continuous variable, is an important determinant of the compartment-specific features of radiographic knee OA. Further work is required to determine whether interventions aimed at correcting these relatively minor levels of varus and valgus angulation will have an effect on the risk of tibiofemoral OA.     

Prevalence of radiographic primary hip and knee osteoarthritis in a representative Central European population

The aim of our study was to determine the radiographic prevalence of hip and knee osteoarthritis and compare our results with prevalence data reported by other studies, as no similar study had been performed in Hungary previously. Our aim was also to investigate the usefulness of the different radiological scoring methods for the definition of osteoarthritis. Patients who earlier reported complaints and gave written consent were asked to participate in a clinical follow-up. In the 682 participants Harris hip score, visual analogue pain scale values for both joints, Knee Society score and knee functional score were calculated. Weight-bearing radiographs were taken of both joints. Kellgren-Lawrence radiological evaluation was performed and osteoarthritis prevalence was defined. Hip osteoarthritis was found in 109 cases (16.49%), and knee osteoarthritis was found in 111 cases (16.54%). Harris hip score, Knee Society score, functional score and visual analogue scale values were significantly worse in people with radiographically proven osteoarthritis compared to the control group (p < 0.05). Significantly higher osteoarthritis prevalence of both joints was found in those with increased body mass index values. Age also plays a significant role in the development of both hip and knee osteoarthritis. No significant difference was observed between male and female participants regarding osteoarthritis prevalence. The Kellgren-Lawrence score with a cut-off value of 2 or more is a useful evaluation method for the detection of osteoarthritis prevalence in epidemiological studies; according to our observations, in clinical practice a cut-off value of three or more is more relevant.     

Adipokines correlate with pain in lower limb osteoarthritis: different associations in hip and knee

Purpose

Our aim was to investigate whether serum and synovial-fluid (SF) concentrations of interleukin-6 (IL-6), leptin, adiponectin, resistin or visfatin are associated with joint pain in hip and knee in end-stage osteoarthritis (OA).

Methods

A cross-sectional study assessing patients with hip and knee OA undergoing total joint arthroplasty between January and December 2010 was conducted at a large university hospital. Serum and SF cytokine and adipokine concentrations were determined in samples obtained on the day of surgery. The main outcome was pain severity measured pre-operatively using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and visual analogue scale (VAS) pain scores.

Results

A total of 206 patients were involved (112 with hip and 94 with knee OA). Median age was 72 years [interquartile range (IQR) 66–79], 59 % were women. All adipokine levels were significantly higher in the SF of hip joints than in that of knee joints, except for leptin, which tended to be higher in the knee. In both hip and knee OA, median serum concentrations of leptin, adiponectin, resistin and visfatin exceeded those in SF, whereas for IL-6, median concentrations were much higher in SF than in serum. In hip OA, worse pain was significantly associated with high SF concentrations of IL-6, visfatin and leptin; in knee OA, it was associated with high SF leptin and low SF adiponectin concentrations and a low adiponectin–leptin ratio.

Conclusion

Our findings support a connection between intra-articular concentrations of several adipokines and severity of preoperative OA pain. However, the specific adipokines differed by joints: in hip OA, pain was associated with IL-6 and visfatin and in knee OA with adiponectin; leptin played a role in both hip and knee OA.     

Leg length discrepancy and lower limb alignment after total hip arthroplasty in unilateral hip osteoarthritis patients

Background

Leg length discrepancy (LLD) following total hip arthroplasty (THA) is a leading cause of patient dissatisfaction. However, no reports have described the influence of lower limb alignment on LLD after THA. In the present study, we firstly investigated the change in lower limb alignment after THA. Secondly, we determined the influence of lower limb alignment on LLD after THA. Thirdly, we evaluated the influence of LLD in the entire lower leg on the clinical outcomes after THA.

Methods

We followed up with 54 unilateral hip osteoarthritis (OA) patients 1 year after THA. For the radiological assessment of LLD and lower limb alignment, we obtained anteroposterior radiographs of the pelvis and both lower legs in entirety in a standing position before and 1 year after THA. The Harris Hip Score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Medical Outcomes Study Short-Form 36-Item Health Survey (SF-36) were also obtained to assess the clinical outcome.

Resuts

The alignment of the affected leg, which was more valgus than the unaffected leg before THA, tended toward varus after THA, and the discrepancy between the lower limb alignments on both sides decreased. However, the alignment discrepancies that remained after THA influenced the LLD measured on the radiograph of the entire lower leg, and this LLD influenced the clinical outcome as measured by the HHS and the WOMAC score.

Conclusions

LLD in the entire lower leg should be corrected for a better clinical outcome after THA.     

Association of vitamin D status with knee pain and radiographic knee osteoarthritis

Objective

The objective of the present study was to explore the association of serum vitamin D concentration and polymorphism in the vitamin D receptor (VDR), with knee pain and radiographic knee osteoarthritis (OA) among men and women in a large population-based UK cohort study.

Methods

Seven hundred and eighty-seven participants in the Hertfordshire Cohort Study (399 men, 388 women; mean age 65.6 ± 2.7 years) underwent a questionnaire on knee pain and radiographic knee examination. This study examined the association of Fok1, Cdx2 and Apa1 polymorphism in the gene for the VDR and serum 25(OH)D concentration with knee pain and radiographic knee OA by a generalized estimating equations population averaged logistic regression analysis in the Hertfordshire Cohort Study.

Results

There were no associations of Fok1, Cdx2 and Apa1 polymorphisms of the VDR with knee OA except for Aa for Apa1 compared with AA [Odds ratio (OR) 0.59, 95% confidence interval (CI) 0.36–0.95, P = 0.031]. While, ff for Fok1 (OR 1.60, 95% CI 1.07–2.39, P = 0.022) and AA for Cdx2 polymorphism (OR 2.21, 95% CI 1.07–4.56, P = 0.032) was significantly associated with higher prevalence of knee pain compared with FF for Fok1 and GG for Cdx2, respectively. None of these are statistically significant after adjusting for the three polymorphisms tested. 25(OH)D level was not significantly associated with radiographic knee OA, while, low tertile of 25(OH)D level tended to be associated with knee pain compared with high tertile of 25(OH)D level.

Conclusion

The present cross-sectional study using a large-scale population from the Hertfordshire Cohort study indicated that vitamin D may be associated with pain rather than radiographic change, but the evidence for an association between vitamin D genetic variation and pain in knee OA is very weak in the present study. Further replication of our results will be required to elucidate the association of vitamin D and knee OA.     

Timing of physiodesis in limb length inequality

In a prospective study 30 children underwent 33 physiodeses for lower limb length inequality (LLI). Timing of surgery was based on (bi)annual orthoradiographic measurements and skeletal age, and in accordance with Moseley's Straight Line Graph. The mean predicted LLI was 5.2 (3.0–11) cm and the mean LLI at the end of growth was 1.4 (0.0–4.3) cm. In 9 patients final LLI exceeded 1.5 cm, and one of these patients was operated on twice. In total, secondary operations were performed three times.

After analysis of the failures it is concluded that the accuracy of the Straight Line Graph is mainly limited by the pattern of skeletal maturation. Recommendations to prevent failures from other causes are given.     

Genetic epidemiology of hip and knee osteoarthritis

Osteoarthritis (OA) is the most common cause of arthritis and represents an enormous healthcare burden in industrialized societies. Current therapeutic approaches for OA are limited and are insufficient to prevent the initiation and progression of the disease. Genetic studies of patients with OA can help to unravel the molecular mechanisms responsible for specific disease manifestations, including joint damage, nociception and chronic pain. Indeed, these studies have identified molecules, such as growth/differentiation factor 5, involved in signaling cascades that are important for the pathology of joint components. Genome-wide association studies have uncovered a likely role in OA for the genes encoding structural extracellular matrix components (such as DVWA) and molecules involved in prostaglandin metabolism (such as DQB1 and BTNL2). A ～300 kilobase region in chromosome 7q22 is also associated with OA susceptibility. Finally, the identification of individuals at a high risk of OA and of total joint arthroplasty failure might be facilitated by the use of combinations of genetic markers, allowing for the application of preventive and disease-management strategies.     

Relationship of plasma and synovial fluid vascular endothelial growth factor with radiographic severity in primary knee osteoarthritis

Purpose

Recent evidence suggests that angiogenesis and inflammation contribute to the development and progression of osteoarthritis (OA). The purpose of this study was to investigate vascular endothelial growth factor (VEGF) levels in plasma and synovial fluid of patients with knee OA and to determine the relationship of VEGF levels with disease severity in knee OA.

Methods

A total of 100 subjects were enrolled in this study (80 knee OA patients and 20 healthy controls). Plasma and synovial fluid VEGF levels were analysed using enzyme-linked immunosorbent assay. VEGF expressions in synovial membrane and articular cartilage samples were assessed using immunohistochemistry.

Results

VEGF level in synovial fluid of knee OA patients was tenfold higher than that in paired plasma (P < 0.001). Both plasma and synovial fluid VEGF exhibited a positive correlation with radiographic severity (r = 0.454 and r = 0.727, P < 0.001, respectively). VEGF expression was highly detectable in synovial lining cells and articular chondrocytes of knee OA patients.

Conclusions

VEGF levels in both plasma and synovial fluid were positively correlated with the severity of knee OA. Therefore, VEGF may be useful for monitoring OA severity and could play a substantial role in the development and progression of knee OA.     

Leg length inequality after total hip arthroplasty

Leg length inequality (LLI) in 55 patients with cemented total hip arthroplasty (THA) was measured from weight-bearing anteroposterior (AP) hip radiographs. The mean radiologic LLI was 8.7 mm in unilateral and 11.6 mm in bilateral THA, differing significantly from the clinically measured values (2.8 mm and 4.2 mm, respectively). LLI as a cause of aseptic loosening and unexplained pain warrants investigation in THA patients.     

全髋人工关节置换术的肢体不等长

目的: 探讨THA术恢复双下肢等长的重要性及方法。方法: 对 73例单侧THA术患者进行随访, 随访时间 21 ~76个月 (平均 38. 9个月 )。X线片测量下肢的长短及股骨偏心距, 对X线片测量数据进行统计学处理。结果: 术后 90. 4%的患者 ( 66例 ) 出现下肢长度差别, 两侧髋臼顶至泪滴连线距离差与肢体长度差存在明显负相关关系 (r=-0. 612, P<0. 001), 股骨偏心距与下肢长度差存在明显相关关系 (r=0. 434, P=0. 003)。结论: THA的肢体不等长问题不容忽视, 强调术前肢体长度及模板测量, 术中正确评估肢体长度, 可获得满意结果。     

Age-related quadriceps-dominant muscle atrophy and incident radiographic knee osteoarthritis

Muscle atrophy is common in the elderly. However, the etiologic role of muscle atrophy associated with osteoarthritis of the knee has not been studied in detail. We assessed the association between age-related muscle atrophy around the knee joint and incident radiographic osteoarthritis of the knee. Twenty-one women in their thirties and 17 women in their sixties participated. They had no history, symptoms, or objective findings of any knee problems, and none of the participants was limited in performing daily activities. Radiographs of the knee joint were graded for the presence of osteoarthritis, and the cross-sectional imaging around the knee joint was carried out using computed tomography. Incident radiographic osteoarthritis was observed in 6 of the 17 women in their sixties. Quadriceps-dominant muscle atrophy was marked in the elderly women with radiographic osteoarthritis. In a multivariate analysis, the risk of incident radiographic osteoarthritis of the knee was significantly increased among women with a higher hamstrings/quadriceps cross-sectional area ratio. The results suggest the possibility that age-related quadriceps-dominant muscle atrophy may play a role in the pathogenesis of osteoarthritis of the knee.     

Knee extensor muscle weakness and radiographic knee osteoarthritis progression

Background and purpose — Knee extensor (KE) muscle weakness is a modifiable feature commonly observed in individuals with knee osteoarthritis (KOA) and constitutes a potential target for patient-specific interventions. Therefore, in this study, we explored whether KE weakness is associated with radiographic (medial and/or lateral) KOA progression and how this relationship differs depending on frontal plane knee alignment and sex.

Patients and methods — We studied 3,075 knees (1,961 participants, 58% female) from the Osteoarthritis Initiative with radiographic Kellgren–Lawrence grade 1–3. Peak KE torque (Nm/kg) was assessed at baseline, and progression defined as fixed-location joint space width loss (≥ 0.7mm) in medial and lateral tibiofemoral compartments from baseline to 4-year follow-up. Knee-based generalized estimating equations, stratified by alignment (malaligned vs. neutral), estimated the relative risk (RR) of progression for those in the lowest (and middle) vs. highest KE torque group (split by tertiles). Secondary analyses explored whether this relationship was compartmental- or sex-specific.

Results — Being in the lowest (or middle) compared with the highest torque group increased the risk of progression in neutrally aligned knees (relative risk [RR] 1.2 [95% CI 1.0–1.4]; and 1.2 [CI 1.0–1.4], respectively), but not after adjusting for age, sex, BMI, pain, and radiographic severity. In secondary analyses, women with neutral alignment in the lowest compared with the highest torque group had significantly increased risk of lateral compartment progression independent of age, BMI, disease severity, and pain (RR 1.3 [CI 1.0–1.8]). No association was observed between KE torque and KOA progression in men, irrespective of alignment.

Interpretation — These results identify a potentially important clinical phenotype: KE weakness may be a more important risk factor for radiographic KOA progression in women without knee malalignment.