Reported Knee Pain Research Articles

Isokinetic strength training of lower limb muscles following acquired brain injury

Primary objective: To investigate the effectiveness of isokinetic strength training of ankle and knee muscles in adults with chronic acquired brain injury (ABI).Research design: Series of single case studies.Methods: Twelve people with ABI participated in a 2.5-week baseline, 12-week intervention and a 4-week follow-up phase.Intervention: Concentric isokinetic exercise, twice a week, for plantarflexors (PFs), dorsiflexors (DFs), knee flexors (KFs) and knee extensors (KEs).Outcomes: Peak torque and power at 60 and 90° s−1, PFs and KFs tone at 60° s−1, gait speed and timed chair rises.Results: For single case analyses strength improvements were noted in 11/12 participants’ PFs, 5/12 participants’ DFs and 7/12 participants’ KEs and KFs. Gait speed improved in 8/12 participants and chair rise time improved in 7/12 participants. PFs tone increased in three participants, KFs tone increased in six participants and three participants reported knee pain. For group analyses, peak torque of PFs and KEs, fast gait speed and timed chair rises demonstrated improvement (p < 0.05).Conclusions: Isokinetic strength training may be effective to improve lower limb muscle strength; however, care needs to be taken in selecting suitable candidates as some individuals reported knee pain with this intensive programme.

Disability and common treatment strategies associated with knee pain in a rural Chinese population

To estimate the burden of disability and health services use by people with knee pain, with or without radiographic evidence of osteoarthritis (OA), in rural northern China. A population-based cross-sectional survey was conducted among 1030 residents of Wuchuan County, Inner Mongolia, aged 50 years old and over. The participants completed an interviewer-based questionnaire and obtained bilateral weight-bearing posterior-anterior semi-flexed knee radiographs. Of 1027 participants with knee radiographs, 513 (50%) participants reported knee pain in most days of at least a month over the past 12 months. Of those with knee pain, 109 (21%) had radiographic OA (Kellgren Lawrence grade > or =2) in symptomatic knees. Adjusting for age, gender, BMI, education and back pain, the presence of knee pain was associated with a significantly greater difficulty in walking, climbing 10 steps, stooping, performing cleaning chores and preparing meals. Among 513 subjects with knee pain, the presence of radiographic disease was significantly associated with the presence of unbearable pain (36% vs. 59%), restricted activity (39% vs. 64%), use of NSAIDs (78% vs. 88%) and consulting a doctor over the last 12 months (33% vs. 59%). Knee pain is associated with significant physical disability in rural China The prevalent use of NSAIDs for knee pain and a low use of knee surgery should be of particular concerns. These findings will be useful to guide the distribution of future health care resources and preventive strategies.

Case definitions of knee osteoarthritis in 4,151 unselected subjects: relevance for epidemiological studies

The aims of the present study were threefold: to examine the distribution of knee joint osteoarthritis in a large, standardized radiological study; to examine the relationships between self reported knee pain and radiological OA; and to examine the natural history of radio-morphological change over age in individuals without radiological features of OA. The Copenhagen Osteoarthritis Study - COS is a substudy of the Copenhagen City Heart Study, a longitudinal regional health survey. From the third inclusion of the CCHS (1992-1994) 4,151 subjects were selected for subsequent standardized radiography of the pelvis, the knees, the hands, the wrists, and the lumbar spine. Images were analyzed and knee joint osteoarthritis (OA) was classified according to the radiographic atlas of Kellgren and Lawrence. Joint space width (JSW) was measured at three sites within both the medial and the lateral compartment. For the entire cohort the prevalence of radiological knee joint OA of all grades was 38.7% for men and 44.2% for women. Age stratification documented increasing knee joint OA both in regard to prevalence and morphological severity. Knee pain was universally correlated to the Kellgren and Lawrence severity of OA. In a subgroup with no features of radiological OA, a significant and linear decline in JSW with increasing age was found. We found a clear relationship between self-reported knee pain and radiological osteoarthritis. Pain was proportionally related to the severity of change. We also demonstrated a significant diminishing of joint space width with increasing age in individuals without apparent radiological degeneration.

Marked disability and high use of nonsteroidal antiinflammatory drugs associated with knee osteoarthritis in rural China: a cross-sectional population-based survey

IntroductionThe burden of disability, analgesia, and health services use associated with knee pain and osteoarthritis (OA) in developing countries is relatively unknown, despite a high proportion of these populations required to be engaged in heavy occupational physical activity throughout their life span. The aim of this survey was to estimate the burden of disability, analgesia, and health services use associated with knee pain in rural China.MethodsThis was a population-based cross-sectional survey among residents, aged 50 years and older, of Wuchuan County, Inner Mongolia. Participants completed an interviewer-based questionnaire, evaluating knee pain and associated disability, analgesia, and health services use, and obtained bilateral standardized weight-bearing knee radiographs.ResultsOf the 1,027 participants, 513 (50%) reported knee pain on most days of at least 1 month in the past year, with 109 (21%) also demonstrating radiographic OA (Kellgren-Lawrence grade ≥2) in the symptomatic knee. Adjusting for age, gender, body mass index (BMI), education, and back pain, the presence of knee pain was associated with significantly greater difficulty in walking, climbing 10 steps, stooping, completing cleaning chores, and preparing meals. Among the 513 subjects with knee pain, the additional presence of radiographic evidence of OA was significantly associated with more occasions of "unbearable" pain (59% versus 36%) and restricted activity (64% versus 39%), as well as increased use of nonsteroidal antiinflammatory drugs (NSAIDs) (88% versus 78%) and the reported number of doctor visits (59% versus 33%) in the past year. The use of paracetamol for knee pain was rare (6% versus 2%).ConclusionsKnee pain is highly prevalent in rural northern China. The associated significant disability and marked preferential use of NSAIDs as analgesia should be of concern in these communities reliant on heavy occupational physical activity for their livelihood. The findings will be useful to guide the distribution of future health care resources and preventive strategies. A similar article has been published in the Chinese language journal, National Medical Journal of China.

Non-consultation among community-dwelling older adults with knee pain: completing the picture

AimTo investigate knee-related and comorbid consultations in a sample of community-dwelling older adults with knee pain.BackgroundKnee pain affects 25–37% of people aged over 50 years. Previous studies suggest a minority will consult their general practitioner (GP) about it. One reason might be the relatively low priority given to this problem in the context of multi-morbidity.MethodsAdults aged over 50 years, registered with three local general practices reporting knee pain within the last 12 months, were recruited to an observational cohort. Consultation data were reviewed for the three-year period following study entry. All knee-related consultations, including those for knee osteoarthritis (OA), were identified. Contacts for non-knee-related morbidity were also identified. Consultation patterns were summarized as incidence rates using exact person–time and cumulative incidences.FindingsSeven hundred and forty-two people (mean age 65.5 years (SD 8.6); 54% female) were included and provided 1917 person–years of observation. The rate of knee-related consultations was 38.5 per 100 person–years (95% CI 35.8, 41.3), of knee OA consultations 10.6 (9.2, 12.1), and of comorbid contacts 790.6 (778.0, 803.3). The cumulative incidence of knee-related consultation at three years was 41.0%. Knee-related consultation was related to severity of knee pain but almost 50% with high levels of pain intensity did not visit the GP about their knee problem. Contrastingly, within six months of study entry 85.6% of participants had contacted the practice about other comorbid illness (predominately circulatory disease or other musculoskeletal complaints). By three years, 99.6% participants had consulted about comorbid illness. Incidence rates for knee-related consultations and comorbid contacts were associated with the relative importance the patient gave to their knee problem. For every knee-related consultation there were 20 comorbid contacts. There is considerable scope for opportunistic care of knee pain and for further research on how patients and GPs prioritize health conditions in the context of multi-morbidity.

Lifestyle interventions for knee pain in overweight and obese adults aged ≥45: economic evaluation of randomised controlled trial

Objective To estimate the cost effectiveness of four different lifestyle interventions for knee pain.Design Cost utility analysis of randomised controlled trial.Setting Five general practices in the United Kingdom.Participants 389 adults...

The association of BMI and knee pain among persons with radiographic knee osteoarthritis: A cross-sectional study

BackgroundMany people with radiographic knee osteoarthritis (RKOA) do not present with pain. It is suspected that such persons tend toward lower body mass index (BMI). The purpose of the study was to explore the relationship between BMI and knee pain among persons with RKOA.MethodsSubjects in the Clearwater Osteoarthritis Study with RKOA (N = 576) were classified as reporting knee pain (Pain) or no knee pain (No Pain). WHO-classified BMI categories were compared by pain status. Odds ratios were calculated for the four elevated BMI groups, with the normal BMI group as the reference group. Elevated BMI was the risk factor, and knee pain status was the outcome factor.ResultsPain subjects presented with a higher mean BMI (30.4 kg/m2) compared with No Pain subjects (27.5 kg/m2) (p < 0.0001). Unadjusted and adjusted odds ratios demonstrated a positive association between BMI group and pain for each successive elevated BMI category. Adjusted odds ratios ranged from 1.6 for the Pre-obese group (p < 0.05) to 7.5 for the Obese III group (p < 0.0001).ConclusionAmong subjects with RKOA, those presenting with an elevated BMI had a greater likelihood of knee pain compared to subjects with a normal BMI, and this chance rose with each successive elevated BMI category. As BMI is a modifiable risk factor, longitudinal research is needed to confirm these findings and elucidate the mechanisms underlying this relationship.

Pain Catastrophizing and Pain-Related Fear in Osteoarthritis Patients: Relationships to Pain and Disability

This study examined the degree to which pain catastrophizing and pain-related fear explain pain, psychological disability, physical disability, and walking speed in patients with osteoarthritis (OA) of the knee. Participants in this study were 106 individuals diagnosed as having OA of at least one knee, who reported knee pain persisting for six months or longer. Results suggest that pain catastrophizing explained a significant proportion (all Ps ≤ 0.05) of variance in measures of pain (partial r 2 [p r 2] = 0.10), psychological disability (p r 2 = 0.20), physical disability (p r 2 = 0.11), and gait velocity at normal (p r 2 = 0.04), fast (p r 2 = 0.04), and intermediate speeds (p r 2 = 0.04). Pain-related fear explained a significant proportion of the variance in measures of psychological disability (p r 2 = 0.07) and walking at a fast speed (p r 2 = 0.05). Pain cognitions, particularly pain catastrophizing, appear to be important variables in understanding pain, disability, and walking at normal, fast, and intermediate speeds in knee OA patients. Clinicians interested in understanding variations in pain and disability in this population may benefit by expanding the focus of their inquiries beyond traditional medical and demographic variables to include an assessment of pain catastrophizing and pain-related fear.

A prognostic approach to defining chronic pain: Application to knee pain in older adults

A prognostic approach to defining chronic pain has been proposed as an alternative to traditional definitions based on retrospective duration of pain. While this new approach performs well in low back pain (LBP), headache and orofacial pain, it is not known whether it translates to regional pain syndromes with an underlying pathological component, such as osteoarthritis (OA). We investigated the performance of this approach in a population-based cohort of older adults reporting knee pain, with a spectrum of radiographic knee OA. 676 adults (50 years+) attended a research clinic and were followed up at 18 months and 3 years. Risk scores were calculated using pain intensity, pain duration, pain-related activity, number of pain sites and depressive symptoms, measured at baseline and at 18 months. These scores were used to determine the probability of future clinically significant knee pain, defined as Chronic Pain Grade II–IV, at 18 months and at 3 years using logistic regression. Cut-points on the risk score were applied to determine groups at intermediate (probability ⩾0.2), possible (⩾0.5) and probable (⩾0.8) risk of clinically significant knee pain. Discriminative ability of the risk scores, determined by area under the ROC curve, was high (0.78–0.82), varied little by radiographic severity and was superior to pain duration alone. The derived cut-points suggested a lower threshold for each of the risk groups than the previous LBP work. This prognostic approach to defining chronic pain appears to translate well to knee pain. Different cut-points for defining risk groups may be needed for different pain syndromes.

Gender difference in symptomatic radiographic knee osteoarthritis in the Knee Clinical Assessment – CAS(K): A prospective study in the general population

BackgroundA recent study of adults aged ≥50 years reporting knee pain found an excess of radiographic knee osteoarthritis (knee ROA) in symptomatic males compared to females. This was independent of age, BMI and other clinical signs and symptoms. Since this finding contradicts many previous studies, our objective was to explore four possible explanations for this gender difference: X-ray views, selection, occupation and non-articular conditions.MethodsA community-based prospective study. 819 adults aged ≥50 years reporting knee pain in the previous 12 months were recruited by postal questionnaires to a research clinic involving plain radiography (weight-bearing posteroanterior semiflexed, supine skyline and lateral views), clinical interview and physical examination. Any knee ROA, ROA severity, tibiofemoral joint osteoarthritis (TJOA) and patellofemoral joint osteoarthritis (PJOA) were defined using all three radiographic views. Occupational class was derived from current or last job title. Proportions of each gender with symptomatic knee ROA were expressed as percentages, stratified by age; differences between genders were expressed as percentage differences with 95% confidence intervals.Results745 symptomatic participants were eligible and had complete X-ray data. Males had a higher occurrence (77%) of any knee ROA than females (61%). In 50–64 year olds, the excess in men was mild knee OA (particularly PJOA); in ≥65 year olds, the excess was both mild and moderate/severe knee OA (particularly combined TJOA/PJOA). This male excess persisted when using the posteroanterior view only (64% vs. 52%). The lowest level of participation in the clinic was symptomatic females aged 65+. Within each occupational class there were more males with symptomatic knee ROA than females. In those aged 50–64 years, non-articular conditions were equally common in both genders although, in those aged 65+, they occurred more frequently in symptomatic females (41%) than males (31%).ConclusionThe excess of knee ROA among symptomatic males in this study seems unlikely to be attributable to the use of comprehensive X-ray views. Although prior occupational exposures and the presence of non-articular conditions cannot be fully excluded, selective non-participation bias seems the most likely explanation. This has implications for future study design.

The influence of consulting primary care on knee pain in older people: a prospective cohort study

Objective:To investigate whether consulting a general practicioner (GP) in the 3 years after reporting knee pain is linked to better knee pain outcomes (reduced presence or severity of knee pain)...

Predicting the course of functional limitation among older adults with knee pain: do local signs, symptoms and radiographs add anything to general indicators?

Objective:To determine the additional prognostic value of clinical history, physical examination and x-ray findings to a previously derived simple generic model (age, body mass index, anxiety and pain severity) in...

If You Want Patients with Knee Osteoarthritis to Exercise, Tell Them about NSAIDs

PURPOSE: Exercise is an important adjunctive treatment for knee OA; however it is underutilized, in part because of the known difficulties related to initiating and adhering to exercise programs. Although there are ample data documenting the latter, patient preferences for exercise in comparison to other options have not been examined. METHODS: Participants were recruited as part of an intervention trial to improve decision-making in knee OA. Patients with knee pain on most days of the preceding month completed an Adaptive Conjoint Analysis interactive computer survey designed to elicit patient preferences for a cream (capsaicin), oral medications, [acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs)], intra-articular (IA) injections (up to four times per year) and exercise (low impact aerobic exercise and/or strength training three times per week). Preferences were determined based on individual respondent's trade-offs between: route of administration, probability of having less pain, probability of improved strength and endurance, risk of dyspepsia, and risk of ulcer. Preferences were calculated as "shares" which sum to 100. RESULTS: 90 subjects completed the computer tool; mean age ± SD = 68 ± 9 (range = 53-87). Patients preferred exercise over other treatment options whether IA injections and NSAIDs were described as being 20% or 50% more effective at decreasing symptoms compared to other options. The relative importance assigned to treatment benefits and risks were 29% and 41% respectively. Patient demographic characteristics were not related to preferences; however, patients with more self reported knee pain were less likely to prefer exercise compared to their counterparts (r = -0.3, p=0.004). CONCLUSIONS: In this study, patients preferred exercise over pharmacologic options for treatment of knee OA. Preferences were driven by patients' unwillingness to accept the risk of adverse effects. Our findings also suggest that subjects with greater knee pain may be more reluctant to exercise compared to their counterparts. Presentation of exercise in the context of other available therapies might increase patient willingness to try exercising by making the trade-offs between exercise and medications more apparent.

Clinical effectiveness of a rehabilitation program integrating exercise, self‐management, and active coping strategies for chronic knee pain: A cluster randomized trial

ObjectiveChronic knee pain is a major cause of disability and health care expenditure, but there are concerns about efficacy, cost, and side effects associated with usual primary care. Conservative rehabilitation may offer a safe, effective, affordable alternative. We compared the effectiveness of a rehabilitation program integrating exercise, self-management, and active coping strategies (Enabling Self-management and Coping with Arthritic Knee Pain through Exercise [ESCAPE-knee pain]) with usual primary care in improving functioning in persons with chronic knee pain.MethodsWe conducted a single-blind, pragmatic, cluster randomized controlled trial. Participants age ≥50 years, reporting knee pain for >6 months, were recruited from 54 inner-city primary care practices. Primary care practices were randomized to continued usual primary care (i.e., whatever intervention a participant's primary care physician deemed appropriate), usual primary care plus the rehabilitation program delivered to individual participants, or usual primary care plus the rehabilitation program delivered to groups of 8 participants. The primary outcome was self-reported functioning (Western Ontario and McMaster Universities Osteoarthritis Index physical functioning [WOMAC-func]) 6 months after completing rehabilitation.ResultsA total of 418 participants were recruited; 76 (18%) withdrew, only 5 (1%) due to adverse events. Rehabilitated participants had better functioning than participants continuing usual primary care (−3.33 difference in WOMAC-func score; 95% confidence interval [95% CI] −5.88, −0.78; P = 0.01). Improvements were similar whether participants received individual rehabilitation (−3.53; 95% CI −6.52, −0.55) or group rehabilitation (−3.16; 95% CI −6.55, −0.12).ConclusionESCAPE-knee pain provides a safe, relatively brief intervention for chronic knee pain that is equally effective whether delivered to individuals or groups of participants.

Knee pain and osteoarthritis in the general population: what influences patients to consult?

We examined the relationship between predisposing factors, enabling factors and need-related factors with consultation for knee pain in general practice. This was a retrospective review of computerized medical records for knee-related consultations in the 18 months before baseline assessment of individuals aged over 50 years reporting knee pain in the previous 12 months. The association between each factor and consultation for consulters compared to non-consulters was summarized using odds ratios (ORs). Interaction between each variable and chronic pain grade was investigated. The association between knee-related consultation and the number and type of other co-morbid consultations was then determined. In total, 742 participants were assessed. Of these, 209 (28%) had a knee-related consultation in the previous 18 months. Recent onset of pain [OR 3.2; 95% confidence interval (95% CI) 1.8, 5.7] and severity of pain, Grade III/IV (OR 3.4; 95% CI 2.1, 5.6), were associated with knee-related consultation. Those rating their knee problem as a health priority were more likely to consult (OR 3.2; 95% CI 1.6, 6.7). Irrespective of knee pain severity, there was no difference in the median number of co-morbid consultations between knee consulters and knee non-consulters. Need-related factors appeared to be associated with the decision to consult about knee pain. Neither the presence of self-reported selected co-morbid conditions nor the total number of co-morbid conditions was related to consultations for knee pain. Nevertheless, 50% of those with severely disabling knee pain still did not consult for it. Further investigation of this is important in order to optimize care for patients with knee pain and co-morbid disease.

Estimating the probability of radiographic osteoarthritis in the older patient with knee pain

To determine whether clinical information can practically rule in or rule out the presence of radiographic osteoarthritis in older adults with knee pain. We conducted a cross-sectional diagnostic study involving 695 adults ages >/=50 years reporting knee pain within the last year identified by postal survey and attending a research clinic. Potential indicators of radiographic osteoarthritis were gathered by self-complete questionnaires, clinical interview, and physical examination. Participants underwent plain radiography (posteroanterior, skyline, and lateral views). Radiographic osteoarthritis was defined as the presence of definite osteophytes in at least 1 joint compartment of the index knee. Independent predictors of radiographic osteoarthritis were age, sex, body mass index, absence of whole leg pain, traumatic onset, difficulty descending stairs, palpable effusion, fixed-flexion deformity, restricted-flexion range of motion, and crepitus. Using this model, 245 participants had a predicted probability >/=80% (practical rule in), of whom 231 (94%) actually had radiographic osteoarthritis (specificity 93%). Twenty-one participants had a predicted probability <20% (practical rule out), of whom only 2 (10%) had radiographic osteoarthritis (sensitivity 99.6%). The predicted probability of radiographic osteoarthritis for the remaining 429 participants fell into an intermediate category (20-79%). Simple clinical information can be used to estimate the probability of radiographic osteoarthritis in individual patients. However, for the majority of community-dwelling older adults with knee pain this method enables the presence of radiographic osteoarthritis to be neither confidently ruled in nor ruled out. Prospective validation and updating of these findings in an independent sample is required.

Knee osteoarthritis in community-dwelling older adults: are there characteristic patterns of pain location?

To determine whether there are characteristic patterns of pain location associated with knee osteoarthritis (OA) among community-dwelling older adults. Population-based, cross-sectional survey of 697 adults aged 50 years and over reporting knee pain within the past 6 months. Pain at 13 individual sites at or around the knee was coded. Pain locations in participants with and without "symptomatic knee OA" (defined as symptoms on most days in the past month, at least a definite osteophyte on plain X-ray, and current pain intensity of at least 2 out of 10) were compared. Participants were then grouped by pattern of knee pain location, and their clinical and radiographic characteristics compared. Generalised knee pain (n=313) and medial knee pain (either in isolation or with peripatellar or lateral knee pain: n=175) were the most common patterns. Medial knee pain and distally radiating pain were significantly more likely in those with symptomatic knee OA. Individuals with generalised knee pain with radiation had more persistent, severe pain, and a relatively high proportion had moderate or severe radiographic disease. No single pattern of pain location is pathognomonic for knee OA. Attention towards the role of peripheral nociception and central sensitisation in producing medial knee pain and distally radiating knee pain is warranted.

Health care utilization: measurement using primary care records and patient recall both showed bias

Objective To assess reasons for discrepancies between primary care consultation measured from patient self-report and that based on medical records. Methods Retrospective comparison of recalled consultation in previous 12 months among 2,414 subjects aged 50+ who reported knee pain in a population survey vs. primary care medical records. Record review included (1) all knee morbidity codes and (2) knee problems mentioned in consultation text. It was then extended to: (3) more than 12 months before survey, and (4) consultations for leg or widespread problems (e.g., generalized osteoarthritis). Results In those who reported knee pain, recalled consultation prevalence for knee problems “in past year” was 33% compared with 15% based on medical records. Forty percent of those with a recalled consultation had a recorded knee problem in the same time period (kappa = 0.43). Expanding record search to include leg and widespread problems, and knee problems up to 40 months prior to survey, increased “verified” self-reported consulters to 80%. Conclusions Disparity in estimates of consultation prevalence arose from inaccuracy of: (1) recall in survey responders and (2) recording by general practitioners of specific problems and repeat consultations. Perceived importance of problem in a multiproblem contact and whether it leads to an outcome (e.g., prescription) may influence recording. Implications exist for service provision projections and research.

The Knee Clinical Assessment Study – CAS(K). A prospective study of knee pain and knee osteoarthritis in the general population: baseline recruitment and retention at 18 months

BackgroundSelective non-participation at baseline (due to non-response and non-consent) and loss to follow-up are important concerns for longitudinal observational research. We investigated these matters in the context of baseline recruitment and retention at 18 months of participants for a prospective observational cohort study of knee pain and knee osteoarthritis in the general population.MethodsParticipants were recruited to the Knee Clinical Assessment Study – CAS(K) – by a multi-stage process involving response to two postal questionnaires, consent to further contact and medical record review (optional), and attendance at a research clinic. Follow-up at 18-months was by postal questionnaire. The characteristics of responders/consenters were described for each stage in the recruitment process to identify patterns of selective non-participation and loss to follow-up. The external validity of findings from the clinic attenders was tested by comparing the distribution of WOMAC scores and the association between physical function and obesity with the same parameters measured directly in the target population as whole.Results3106 adults aged 50 years and over reporting knee pain in the previous 12 months were identified from the first baseline questionnaire. Of these, 819 consented to further contact, responded to the second questionnaire, and attended the research clinics. 776 were successfully followed up at 18 months. There was evidence of selective non-participation during recruitment (aged 80 years and over, lower socioeconomic group, currently in employment, experiencing anxiety or depression, brief episode of knee pain within the previous year). This did not cause significant bias in either the distribution of WOMAC scores or the association between physical function and obesity.ConclusionDespite recruiting a minority of the target population to the research clinics and some evidence of selective non-participation, this appears not to have resulted in significant bias of cross-sectional estimates. The main effect of non-participation in the current cohort is likely to be a loss of precision in stratum-specific estimates e.g. in those aged 80 years and over. The subgroup of individuals who attended the research clinics and who make up the CAS(K) cohort can be used to accurately estimate parameters in the reference population as a whole. The potential for selection bias, however, remains an important consideration in each subsequent analysis.

The management of knee pain in primary care: factors associated with consulting the GP and referrals to secondary care

To investigate the treatment of knee pain in primary care and the factors associated with consulting general practitioners (GPs) and referrals to specialist services. Individuals with knee pain were identified through postal questionnaires sent to patients aged 50 and over from two GP practices in southeast London. Patients with knee pain were then invited to the department, where demographic, clinical and service use data were collected. Participants also completed measures of pain, function, handicap and illness beliefs. From the 2940 questionnaires that were sent out, the response rate was 34%. Of these, 49% reported experiencing knee pain in the previous 12 months. Two hundred and thirty-one patients with knee pain attended the department. One hundred and thirty-four (58%) had seen their GP about their knee pain, with 50 (37%) referred on to specialist services. Compared with non-consulters, consulters had more severe disease and higher levels of disability and handicap, and believed the condition was more severe and had major consequences on their lives. Those referred to specialist care had higher levels of handicap and also believed the condition was more severe, with major consequences on their lives, than those not referred. In this sample nearly half of those who reported knee pain had not seen their GP and were self-managing their condition. A mixture of physical, social and psychological factors predicted visits to GPs and rates of referral to secondary care. Patient perceptions about knee pain were important predictors of both consultations and referrals, highlighting the need to address both physical and psychosocial factors in relation to help-seeking.