Meniscal extrusion and bone marrow lesions are associated with incident and progressive knee osteoarthritis.

OBJECTIVE: Whether meniscal extrusion and bone marrow lesions (BMLs) are independently associated with the risk of knee osteoarthritis (OA) is unknown. METHODS: Data was extracted from the Osteoarthritis Initiative (OAI) cohort. Participants were grouped according to the absence (Kellgren-Lawrence (KL) grade ≤ 1, n = 2120) or presence (KL ≥ 2, n = 2249) of radiographic OA (ROA). Baseline meniscal extrusion and tibial BMLs were assessed. Tibial plateau cartilage volume was assessed at baseline and 72 months, while radiographic disease was assessed at baseline and 48 months. Total knee replacement (TKR) was assessed at 72 months. RESULTS: In those with ROA, the presence of a baseline meniscal extrusion (independent of BMLs) was associated with accelerated cartilage volume loss (medial tibia: -2.1%/annum vs -1.5%; lateral: -2.6%/annum vs -1.6%; both P < 0.001), progressive ROA and TKR (Odds ratio (OR) range 1.4-1.8; 95% CI range 1.1-2.9). The presence of a baseline BML was associated with accelerated cartilage volume loss (medial tibia: -2.1%/annum vs -1.6%; lateral: -1.9%/annum vs -1.6%; P ≤ 0.02), progressive ROA and joint replacement (OR range 1.5-2.4; 95% CI range 1.1-3.4). In those with no ROA, a baseline medial meniscal extrusion was associated with accelerated cartilage volume loss (medial tibia: -2.1%/annum vs -1.2%, P < 0.001), and a baseline medial BML with incident ROA (OR 1.7, 95% CI 1.1 to 2.9). CONCLUSIONS: The presence of baseline meniscal extrusion and BMLs are associated with incident and progressive knee of each other (OA) and represent important structural targets for the treatment and prevention of knee OA.

Patients' perceived health service needs for osteoarthritis (OA) care: a scoping systematic review.

OBJECTIVE: To identify and synthesise evidence regarding patients' perceived health service needs related to osteoarthritis (OA). DESIGN: A comprehensive systematic scoping review of MEDLINE, PsycINFO, EMBASE and CINAHL (1990-2016) was performed to capture information regarding patient perceived health service needs related to OA. Risk of bias and quality of included articles were assessed. Relevant data were extracted and collated to provide a systematic review of the existing literature. RESULTS: Of the 1384 identified manuscripts, 21 were relevant to areas of patient perceived need, including needs related to medical care, pharmacologic therapy, physiotherapy and exercise therapy and alternative medicine. Key findings included (1) Symptom control drove the need for both conventional and complementary services. (2) An individualized relationship was sought with a practitioner knowledgeable in OA care and who adopted a holistic approach, whether providing conventional or alternative therapies. (3) Medications were required to obtain symptomatic relief, with use tempered by recognition of potential side effects and financial cost. (4) The need for allied health services was recognised, although patient and system issues were barriers to uptake. (5) Patient's attitudes towards joint replacement, orthoses and physical aids were influenced by patient preferences and previous healthcare experiences. CONCLUSION: Patient perceived needs are similar to those suggested by clinical guideline recommendations. Better aligning patient perceived needs with healthcare requirements may improve OA outcomes and optimise healthcare system utilisation.

Osteoarthritis year in review 2015: imaging.

PURPOSE: This narrative review covers original publications related to imaging in osteoarthritis (OA) published in English between 1 April 2014 and 30 April 2015. Novel lessons relating to imaging are described. METHODS: An extensive PubMed database search was performed based on, but not limited to the terms "OA" in combination with "Magnetic resonance imaging (MRI)", "Imaging", "Radiography", "Ultrasound", "Computed tomography (CT)" and "Nuclear medicine" to extract relevant studies. In vitro data and animal studies were excluded. This review focuses on the new developments and observations based on the aforementioned imaging modalities, as well as a 'whole-organ' approach by presenting findings from different tissues (bone, meniscus, synovium, muscle and fat) and joints (hip, lumbar spine and hand). RESULTS AND CONCLUSIONS: Over the past year, studies using imagine have made a major contribution to the understanding of the pathogenesis of OA. Significant work has continued at the knee, with MRI now being increasingly used to assess structural endpoints in clinical trials. This offers the exciting opportunity to explore potential disease modifying OA therapies. There has been a clear interest in the role of bone in the pathogenesis of OA. There is now a growing body of literature examining the pathogenesis of OA at the hip, lumbar spine and hand. The future of imaging in OA offers the exciting potential to better understand the disease process across all joints and develop more effective preventive and therapeutic interventions.

Management options for femoroacetabular impingement: a systematic review of symptom and structural outcomes.

OBJECTIVE: The optimal therapy for femoroacetabular impingement (FAI) is unclear. The aim of this systematic review was to examine the evidence for surgical and non-surgical treatment of FAI on symptom and structural outcomes. DESIGN: MEDLINE and EMBASE were searched electronically. Surgical and non-surgical management strategies were searched with "FAI". Studies which included comparison groups and reported symptom or structural outcomes were included (Levels I-III evidence). A risk of bias assessment was performed. RESULTS: Eighteen studies comparing management strategies for FAI were identified. Most studies had high risk of bias. No study compared surgical and non-surgical treatment. When surgical approaches were compared there was evidence of superior symptom outcomes with arthroscopy compared to open surgery and with labral preservation. There was some evidence that surgical interventions are effective in reducing alpha angle (improved hip shape), but no data on whether this affects long-term outcomes. There was some weak evidence that surgery is associated with structural progression of hip osteoarthritis (OA). CONCLUSIONS: Although evidence supports improvement in symptoms after surgery in FAI, no studies have compared surgical and non-surgical treatment. Therefore no conclusion regarding the relative efficacy of one approach over the other can be made. Surgery improves alpha angle but whether this alters the risk of development or progression of hip OA is unknown. This review highlights the lack of evidence for use of surgery in FAI. Given that hip geometry may be modified by non-surgical factors, clarifying the role of non-surgical approaches vs surgery for the management of FAI is warranted.

Weight satisfaction, management strategies and health beliefs in knee osteoarthritis patients attending an outpatient clinic.

BACKGROUND: Although weight control is important in managing knee osteoarthritis (OA), it is difficult to achieve. Understanding beliefs regarding weight management in people with knee OA may improve weight control. AIMS: To examine differences in bodyweight satisfaction, weight management strategies and weight-related health-beliefs in obese, overweight and normal weight people with knee OA. METHODS: The beliefs and attitudes to weight in 102 people with symptomatic knee OA were ascertained. Participants were classified as being obese, overweight or of normal weight. RESULTS: Although obese and overweight participants were less satisfied with their bodyweight, they were more likely to want to lose weight and to report dieting compared with normal weight participants(P < 0.001 for all) and also more likely to report weight gain in the past 6 months (P < 0.001). While most participants rated food intake to be a main determinant of health, this belief was more common in normal weight participants (P = 0.04). When asked about their own weight gain, obese participants more frequently believed genetic and metabolic factors to be important than normal and overweight participants (P = 0.01). While 51 (53%) believed that increasing activity was more important than dietary change to avoid weight gain, this was more commonly believed by obese and overweight participants (P < 0.05). CONCLUSIONS: Despite desiring and attempting to lose weight, obese people with symptomatic knee OA more commonly reported weight gain. Overweight and obese participants attributed weight gain to non-modifiable factors but believed physical activity is more important than dietary change in weight management. Thus, education regarding the importance of diet as compared with non-modifiable factors and physical activity may improve weight management in obese people with knee OA.

Vastus medialis fat infiltration - a modifiable determinant of knee cartilage loss.

BACKGROUND: There is growing interest in the role of intramuscular fat and how it may influence clinical outcomes. Vastus medialis (VM) is a functionally important quadriceps muscle that helps to stabilise the knee joint. This longitudinal study examined the determinants of VM fat infiltration and whether VM fat infiltration influenced knee cartilage volume. METHODS: 250 participants without any diagnosed arthropathy were assessed at baseline between 2005 and 2008, and 197 participants at follow-up between 2008 and 2010. Ambulatory and sporting activity were assessed and magnetic resonance imaging (MRI) was used to determine knee cartilage volume and VM fat infiltration. RESULTS: Age, female gender, BMI and weight were positively associated with baseline VM fat infiltration (P ≤ 0.03), while ambulatory and sporting activity were negatively associated with VM fat infiltration (P ≤ 0.05). After adjusting for confounders, a reduction in VM fat infiltration was associated with a reduced annual loss of medial tibial (ß = -10 mm(3); 95% CI -19 to 0 mm(3); P = 0.04) and patella (ß = -18 mm(3); 95% CI -36 to 0 mm(3); P = 0.04) cartilage volume. CONCLUSION: This community-based study of healthy adults has shown that VM fat infiltration can be modified by lifestyle factors including weight loss and exercise, and reducing fat infiltration in VM has beneficial effect on knee cartilage preservation. The findings suggest that modifying VM fat infiltration via lifestyle interventions may have the potential to reduce the risk of knee OA.

A prospective study of acute inpatient gout diagnoses and management in a tertiary hospital: the determinants and outcome of a rheumatology consultation.

BACKGROUND: Despite acute gout frequently complicating hospital admissions, diagnosis and management are variable. Rheumatology input may improve patient outcomes. AIM: To examine acute episodes of inpatient gout in a tertiary hospital to determine (i) factors that may lead to rheumatology input being sought and (ii) the differences in outcomes when rheumatology input occurs. METHODS: Data collection occurred between February and October 2012 for inpatients in a tertiary Australian hospital. Data were prospectively collected for all rheumatology consultations with a diagnosis of gout. Subjects who had an inpatient admission complicated by acute gout and who did not have rheumatology input were identified through health information coding from discharge summaries. RESULTS: Fifty-eight patients (41% with rheumatology input) were included in the study. Rheumatology input was significantly more likely when the patient was younger (68.9 years vs 78.4 years; P = 0.04) with knee joint involvement (41.7% vs 3.0%; P < 0.001). When rheumatology input occurred, subjects were more likely to have had a serum urate measured (83% vs 50%; P = 0.009), joint aspiration performed (54.2% vs 0%; P < 0.001), been prescribed acute gout medications at discharge (95.8% vs 61.3%; P = 0.001), a documented discharge plan (91.7% vs 23.5%; P < 0.001) and outpatient follow up (41.7% vs 0%; P < 0.001). CONCLUSION: Among inpatients with acute gout, rheumatology input was more likely to be sought in younger patients with knee joint disease. When rheumatology input occurred, patients were more likely to have a synovial fluid confirmed diagnosis of gout with appropriate acute management and a follow-up plan.

Obesity and adiposity are associated with the rate of patella cartilage volume loss over 2 years in adults without knee osteoarthritis.

OBJECTIVES: The aim of this study was to determine whether measures of obesity and adiposity are associated with the rate of patella cartilage volume loss in healthy adults. METHODS: 297 community-based adults aged 50-79 years with no clinical knee osteoarthritis were recruited at baseline (2003-4). 271 (62% female) subjects were re-examined at follow-up (2006-7). Measures of obesity (body mass index (BMI) and weight) and adiposity (fat mass and percentage fat mass), as well as patella cartilage volume, were determined by established protocols. RESULTS: Patella cartilage volume was lost at an annual rate of 1.8% (95% CI 1.4% to 2.1%). Increased baseline BMI, weight, fat mass and percentage fat mass were all associated with an increased rate of patella cartilage volume loss after adjustment for confounders (all p< or =0.04). The direction and magnitude of the effects were similar for both sexes but the number of men examined was considerably smaller and the associations were not statistically significant. There were no significant associations observed between change in any of the obesity and adiposity measures and the rate of patella cartilage volume loss. CONCLUSION: This study demonstrated that increased levels of obesity and adiposity are associated with an increased annual rate of patella cartilage volume loss in healthy adults. Weight-loss interventions that reduce body mass, or specifically target a reduction in fat mass, may help to reduce the rate at which patella cartilage volume is lost, and subsequently the risk of patellofemoral osteoarthritis.

Change in knee angle influences the rate of medial tibial cartilage volume loss in knee osteoarthritis.

OBJECTIVES: Identifying factors that influence the rate of cartilage loss at the knee may help to prevent or delay the progression of knee osteoarthritis (OA). Changes in knee alignment alter knee joint load and may affect the rate of cartilage loss. The aim of this study was to determine whether change in knee alignment between baseline and 2 years is associated with a change in knee cartilage volume in knee OA in the subsequent 2.5 years. METHODS: Seventy-eight adults with symptomatic knee OA were recruited using a combined strategy. Radiographs were performed at time 0 and 2 years to determine change in knee alignment, measured on a continuous scale. Magnetic Resonance Imaging was performed at 2 and 4.5 years to determine annual percentage change in medial and lateral tibial cartilage volumes. RESULTS: In multivariate analyses, for every 1 degrees change toward genu valgum, there is an associated 0.44% reduction in the rate of annual medial tibial cartilage volume loss (95% CI: -0.85%, -0.04%, P=0.03). Similarly, because our measures of change in alignment and cartilage volume were continuous, these results also implied that for every 1 degrees change toward genu varum, there was an associated 0.44% increase in the rate of annual medial tibial cartilage volume loss. Change in knee angle did not significantly affect the rate of loss of the lateral tibial cartilage volume (P=0.95). CONCLUSION: Our results have demonstrated that progressive change toward genu valgum reduced the annual rate of medial tibial cartilage volume loss in people with knee OA, without expediting the rate of lateral tibial cartilage volume loss. These findings suggest that methods to reduce varus alignment may delay the progression of medial tibiofemoral OA and warrant further investigation.

The determinants of change in patella cartilage volume--a cohort study of healthy middle-aged women.

OBJECTIVES: Although cartilage loss occurs with advancing age and is a hallmark of OA, the factors that affect cartilage change are not well established. The aim of this study was to explore the determinants of change in patella cartilage volume over 2 yrs among healthy middle-aged women with no clinical knee OA. METHODS: One hundred and forty-eight women with no clinical knee OA were recruited from a previous population-based cross-sectional study of healthy women aged 40-67 yrs. MRI was performed at baseline and at 2 yrs, to assess patella cartilage and bone volume. Self-reported exercise was assessed by questionnaire. RESULTS: Annual loss of patella cartilage volume was 1.6% (95% CI 1.2, 1.9). Age was positively associated with patella cartilage volume loss after adjustment for confounders (P = 0.05). For every 1 mm(3) increase in patella bone volume at baseline, annual cartilage loss was reduced by 8.05 mm(3) (95% CI 12.91, 3.19; P < 0.001). Fortnightly participation in exercise promoting an increased heart and respiratory rate for at least 20 min also tended to be associated with a reduced rate of patella cartilage volume loss (P = 0.09). CONCLUSION: Among middle-aged women with no clinical knee OA, advancing age expedites the rate of patella cartilage volume loss, while increased patella bone volume and exercise participation tends to be associated with a reduction in the rate of patella cartilage volume loss. Interventions targeting modifiable factors, such as physical activity, warrant further investigation as they may help to prevent patellofemoral OA.

Foot rotation--a potential target to modify the knee adduction moment.

Isolating the particular joints/limb segments associated with knee adductor moment variability may provide clinically important data that could help to identify strategies to reduce medial tibiofemoral joint load. The aim of this study was to examine whether or not foot and thigh rotation during human locomotion are significant determinants of knee adductor moment variability. Three-dimensional gait analyses were performed on 32 healthy adult women (mean age 54+/-12 years, mean BMI 25+/-4 kg m(-2)) with radiologically normal knees. The relationships between foot rotation, thigh rotation and the external knee adduction moment were examined during early and late-stance phases of the gait cycle. The degree of foot rotation correlated significantly with the magnitude of the peak knee adduction moment during late stance (r=0.40, p=0.024). No significant associations were apparent between thigh rotation and the peak knee adduction moment. The association between foot rotation and the knee adduction moment in this study suggests that women who walk with external rotation at the foot reduce their knee adduction moment during late stance. This result implies that changes in foot kinematics can modify the medial tibiofemoral load during gait, which may be important in the prevention and management of knee osteoarthritis.

Obesity and the female sex, risk factors for knee osteoarthritis that may be attributable to systemic or local leptin biosynthesis and its cellular effects.

Obesity and the female sex represent significant risk factors for osteoarthritis (OA). Few studies have demonstrated a metabolic link between obesity and OA, strengthening the likelihood that biomechanical factors mediate this relationship, possibly via the redistribution of increased body mass to weight-bearing joints. However, it is less plausible that the biomechanical factors that contribute toward the incidence of OA at weight-bearing joints, such as the knee, are similar to those at non-weight bearing joints, such as in the hand. This may suggest that non-examined or unidentified biomechanical and/or systemic factors may be important contributors to the aetiology of OA. Recent developments that have helped to better appreciate the pathophysiology of obesity offer new hope to understanding the link between obesity and OA. The discovery of the obesity gene (ob) and its product leptin may have important implications for the onset and progression of OA. For instance, the greater total body fat of the average adult female may partially account for the gender disparity toward OA, given that females theoretically demonstrate higher levels of adipose derived systemic leptin concentrations than their male counterparts. However, while it was previously thought that adipose cells were only capable of leptin production, osteoblasts and chondrocytes are also capable of leptin synthesis and secretion, inferring that local leptin production may be of great importance. For instance, significant levels of leptin were observed in the cartilage and osteophytes of people with OA, yet few chondrocytes produced leptin in the cartilage of healthy people. Leptin has also been demonstrated to induce anabolic activity in the chondrocytes of rats, which may ultimately confer structural joint changes. This paper hypothesizes that leptin may be an unexamined systemic or local factor that may mediate the metabolic link between obesity and OA and partially account for the gender disparity toward the disease.

Obesity: a preventable risk factor for large joint osteoarthritis which may act through biomechanical factors.

Osteoarthritis (OA) is a common degenerative disease of joints. The major clinical features are pain and stiffness, leading to a decline in physical function, which may ultimately require joint replacement surgery. As no cure exists, current medical intervention focuses on symptomatic relief. Moreover, as no cure is imminent, preventable risk factors for the onset and progression of the disease are of great interest. Obesity is the main preventable risk factor that has been identified. Given that obesity is modifiable by conservative treatment such as weight loss, its potential importance in reducing the incidence of OA cannot be underestimated.

A comparison of gait patterns between the offspring of people with medial tibiofemoral osteoarthritis and normal controls.

OBJECTIVES: The aim of this study was to explore the contribution of biomechanical factors to the development and progression of knee osteoarthritis (OA) by investigating whether the offspring of subjects with medial tibiomfemoral OA demonstrate gait abnormalities in the absence of OA. METHODS: Three-dimensional gait analyses were performed on 9 offspring of people with medial tibiofemoral OA and 9 age, gender and Body Mass Index (BMI) matched individuals with no parental history of knee OA. External knee adduction, extension and flexion moments, as well as the magnitude of foot rotation during early stance were compared between the groups. RESULTS: The offspring of people with medial tibiofemoral OA walked with less external rotation at the foot than control subjects during early stance (4.5 degrees versus 13.5 degrees, p < 0.01). There were no significant differences between groups for the peak knee adduction moments (dominant leg, p = 0.49; non-dominant leg, p = 0.70) or peak knee extension moments (dominant leg, p = 0.46; non-dominant leg, p = 0.48). Moreover, there was no difference between groups for the knee flexion moment occurring when the force adducting the knee was greatest (dominant leg, p = 0.35; non-dominant leg, p = 0.33). CONCLUSIONS: Although the offspring of people with medial tibiofemoral OA walked with less external foot rotation than the control subjects during early stance, whether this increases their risk of developing knee OA is yet to be determined.

Reviewing knee osteoarthritis--a biomechanical perspective.

Osteoarthritis (OA) is the most common form of arthritis and is a major cause of disability in people aged over 65. Despite the major socioeconomic burden imposed by OA, the aetiology of this condition remains unclear. Although controversial, several metabolic factors have been implicated in the disease pathogenesis. Nevertheless, no unequivocal systemic risk factors for the onset or progression of OA have been identified. Recently, there has been a growing interest in the biomechanical factors associated with the pathogenesis of OA. This review aims to discuss several of the more pertinent biomechanical and neuromuscular factors, such as the knee adduction moment and muscle strength, that are becoming increasingly accepted as factors that contribute toward the pathogenesis of knee OA.

Frontal plane knee alignment is associated with a longitudinal reduction in patella cartilage volume in people with knee osteoarthritis.

OBJECTIVES: Varus-valgus alignment of the knee is increasingly becoming recognised as an important biomechanical variable in patellofemoral osteoarthritis (OA). The aim of this study was to determine the cross-sectional and longitudinal relationships between frontal plane knee alignment and patella cartilage volume in people with knee OA. METHODS: Ninety-nine adults with symptomatic knee OA were recruited using a combined strategy including referral from specialist centres, arthritis support groups and media advertising. Both baseline and follow-up X-rays and magnetic resonance imaging (MRI) were performed 2 years apart. Knee alignment and patella cartilage volume were determined from X-ray and MRI, respectively. RESULTS: Annual change in knee alignment was negatively associated with an annual change in the total patella cartilage volume before (P=0.002) and after (P=0.003) adjustment for potential confounders over an average of a 1.9-year period. For every 1 degrees change towards valgus direction, there was a 23.4-mm(3) [95% confidence interval (CI) 8.1 mm(3)-38.7 mm(3)] annual reduction in the total patella cartilage volume. CONCLUSION: This study is the first to clearly demonstrate and quantitate the annual reduction in patella cartilage volume that occurs as knee alignment becomes increasingly valgus in an osteoarthritic cohort. Interventions that aim to minimise change towards valgus alignment may reduce the risk for the onset and progression of patellofemoral OA.

Imaging of knee osteoarthritis.

New imaging modalities are broadening the possibilities in osteoarthritis (OA) research, and are offering new insights to help better understand the pathogenesis of this disease. Although knee radiographs are widely employed in epidemiological and clinical studies to assess structural pathology, joint radiographs provide limited outcome measures in knee OA, and other more valid, reliable and sensitive imaging modalities are now available. In particular, magnetic resonance imaging can directly visualize articular cartilage and other joint structures, such as bone and soft tissue, that are now recognized as part of the disease process. This chapter will examine imaging modalities in the assessment of knee OA, and the impact of these on our understanding of the pathogenesis of this disease.

The natural history of cartilage defects in people with knee osteoarthritis.

OBJECTIVES: Cartilage defects are highly prevalent in subjects with knee osteoarthritis (OA). Although they are associated with increased cartilage loss and joint replacement, there is little data on the natural history of cartilage defects. The aim of this study was to examine the progression of cartilage defects over 2 years in people with knee OA and to identify factors associated with progression. METHODS: One hundred and seventeen subjects with OA underwent magnetic resonance imaging of their dominant knee at baseline and follow-up. Cartilage defects were scored (0-4) at four sites. Bone size of the medial and lateral tibial plateau was determined. Height, weight, body mass index and physical activity were measured by standard protocols. RESULTS: The mean cartilage defect score increased significantly over the 2-year study period in all tibiofemoral compartments (all P<0.001), except the lateral tibial compartment with age and tibial plateau bone area at baseline being predictors of progression. However, there was heterogeneity with 81% progressing at any site, 15% remaining stable and 4% decreasing. CONCLUSION: Over 2 years, cartilage defects tend to progress in people with symptomatic OA, with only a small percentage decreasing in severity. Increasing age and increased bone area are risk factors for progression. Interventions aimed at preventing cartilage defects from occurring and reducing their severity may result in a reduction in the severity of OA, by reducing loss of articular cartilage and subsequent requirement for knee joint replacement.

Femoral sulcus angle and increased patella facet cartilage volume in an osteoarthritic population.

OBJECTIVE: The patellofemoral joint is an example of an incongruent articulation commonly affected by osteoarthritis (OA). The relationship between femoral sulcus angle and the development and progression of patellofemoral OA is unclear. The aim of this study was to examine the relationship between the femoral sulcus angle at baseline and patella cartilage volume at baseline and at 2-year follow-up among community based adults with established knee OA. METHODS: One hundred subjects had magnetic resonance imaging of their symptomatic knee at baseline and at 2-year follow-up. From these images, patella cartilage volume was determined. Radiographic skyline views of the patellofemoral joint were taken at baseline to measure the femoral sulcus angle. RESULTS: For every 1 degrees increase in the femoral sulcus angle (i.e., as the sulcus angle became more shallow) there was an associated 9.1mm3 (95% CI 3.1, 15.0) increase in medial patella cartilage volume at baseline (P=0.003). There was a similar trend that approached statistical significance between the femoral sulcus angle and the lateral patella facet cartilage volume at baseline (P=0.09). There was no association between the femoral sulcus angle at baseline and the change in patella cartilage volume over 2 years in either patellofemoral compartment. CONCLUSION: These results infer that the femoral sulcus angle is a cross-sectional determinant of the amount of patella cartilage, but is not a major determinant of the annual change of patella cartilage volume among people with knee OA. These data suggest that a shallower sulcus in the context of established OA may be an advantageous anatomical variant. Further longitudinal studies are required to determine the role of the femoral sulcus angle in OA.

Vastus medialis cross-sectional area is associated with patella cartilage defects and bone volume in healthy women.

OBJECTIVES: Although vastus medialis and vastus lateralis are important muscular determinants of patellofemoral joint function, it is unclear how these muscles relate to the structure of the patellofemoral joint. The aim of this cross-sectional study was to determine the relationship between the vasti muscles and patella cartilage volume and defects and patella bone volume. METHODS: One hundred and seventy-five women, aged 40-67 years, with no knee pain or clinical lower-limb disease had magnetic resonance imaging (MRI) of their dominant knee. The cross-sectional areas of the distal vastus medialis and lateralis were measured 37.5mm superior to the quadriceps tendon insertion at the proximal pole of the patella. Patella cartilage volume and defects and patella bone volume were measured from these images using validated methods. RESULTS: There was no significant association between the distal vastus medialis cross-sectional area and patella cartilage volume. For every 1mm(2) increase in the distal vastus medialis cross-sectional area, there was an associated increased risk of patella cartilage defects [odds ratio (OR): 1.2; 95% confidence interval (CI) 1.004, 1.5; P=0.05], and an associated increase in patella bone volume (OR: 3.9; 95% CI 2.0, 5.8; P<0.001) after adjustment for potential confounders. There was no significant relationship between vastus lateralis cross-sectional area and measures of patella cartilage or bone. CONCLUSION: An increased cross-sectional area of the distal portion of the vastus medialis muscle is associated with an increased risk of patella cartilage defects, and an increase in patella bone volume among healthy women. Although these results need to be confirmed in longitudinal studies, they suggest that an increase in the distal vastus medialis cross-sectional area is associated with structural change at the patellofemoral joint.