Laurence Wood

Introduction: Patellofemoral joint osteoarthritis (OA) is common and leads to pain and disability. However, current classification criteria do not distinguish between patellofemoral and tibiofemoral joint OA. The objective of this study was to provide empirical evidence of the clinical features of patellofemoral joint OA (PFJOA) and to explore the potential for making a confident clinical diagnosis in the community setting. Methods: This was a population-based cross-sectional study of 745 adults aged ≥50 years with knee pain. Information on risk factors and clinical signs and symptoms was gathered by a self-complete questionnaire, and standardised clinical interview and examination. Three radiographic views of the knee were obtained (weight-bearing semi-flexed posteroanterior, supine skyline and lateral) and individuals were classified into four subsets (no radiographic OA, isolated PFJOA, isolated tibiofemoral joint OA, combined patellofemoral/tibiofemoral joint OA) according to two different cut-offs: 'any OA' and 'moderate to severe OA'. A series of binary logistic and multinomial regression functions were performed to compare the clinical features of each subset and their ability in combination to discriminate PFJOA from other subsets. Results: Distinctive clinical features of moderate to severe isolated PFJOA included a history of dramatic swelling, valgus deformity, markedly reduced quadriceps strength, and pain on patellofemoral joint compression. Mild isolated PFJOA was barely distinguished from no radiographic OA (AUC 0.71, 95% CI 0.66, 0.76) with only difficulty descending stairs and coarse crepitus marginally informative over age, sex and body mass index. Other cardinal signs of knee OA - the presence of effusion, bony enlargement, reduced flexion range of movement, mediolateral instability and varus deformity - were indicators of tibiofemoral joint OA. Conclusions: Early isolated PFJOA is clinically manifest in symptoms and self-reported functional limitation but has fewer clear clinical signs. More advanced disease is indicated by a small number of simple-to-assess signs and the relative absence of classic signs of knee OA, which are predominantly manifestations of tibiofemoral joint OA. Confident diagnosis of even more advanced PFJOA may be limited in the community setting.

Aim: To describe the annual consultation prevalence of different patellofemoral disorders across the adult life span. Background: The knee is the second most common site for musculoskeletal pain. Evidence from sports injury and orthopaedic settings suggests that patellofemoral disorders constitute a significant proportion of knee pain cases, but we have no evidence from general practice – the setting where most patellofemoral problems will present and be dealt with – of the prevalence of consultations for these problems in the different age groups. Methods: Age- and gender-stratified annual person consulting prevalence rates (APCPRs) for patellofemoral disorders were calculated using 2006 data from the ‘Consultations in Primary Care Archive’ (CiPCA) – a fully audited database of continuous morbidity recording used by the general practitioners (GPs) in eight general practices in North Staffordshire. Findings: A total of 57 555 >15-year-olds were registered with the eight general practices in 2006; 1782 made a knee-related consultation, of which 303 (one-in-six) were coded as patellofemoral disorders (APCPR, 53 per 10 000 persons), suggesting that GPs consider a significant proportion of adult knee pain consulters to have patellofemoral disorders. Twelve patellofemoral disorders diagnosed by the GPs were identified. The non-specific diagnosis of ‘anterior knee pain’ (AKP) was by far the most common (APCPR, 37.2/10 000). Other more specific diagnoses were rare by contrast, suggesting that specific patellofemoral disorders are rarely diagnosed in general practice (consultation prevalences, in order of most prevalent first: bursitis (7.8/10 000), patellofemoral osteoarthritis (2.3/10 000); APCPRs for the remaining nine diagnoses ranged between 0 and 1.6/10 000). However, the use of alternative less anatomically specific diagnostic codes, such as for ‘knee pain’, may mean that our estimate of one-in-six is an underestimate of GPs’ true attribution rates to patellofemoral joint disorders of people consulting them with knee pain. AKP was seen equally commonly by GPs across all age strata, contradicting the received wisdom that AKP problems are most common among younger adults.

Background: Exercise therapy for knee pain and osteoarthritis remains a key element of conservative treatment, recommended in clinical guidelines. Yet systematic reviews point to only modest benefits from exercise interventions. One reason for this might be that clinical trials tend to use a one-size-fits-all approach to exercise, effectively disregarding the details of their participants' clinical presentations. This uncontrolled before-after study (TargET-Knee-Pain) aims to test the principle that exercises targeted at the specific physical impairments of older adults with knee pain may be able to significantly improve those impairments. It is a first step towards testing the effectiveness of this more individually-tailored approach. Methods/Design: We aim to recruit 60 participants from an existing observational cohort of community-dwelling older adults with knee pain. Participants will all have at least one of the three physical impairments of weak quadriceps, a reduced range of knee flexion and poor standing balance. Each participant will be asked to undertake a programme of exercises, targeted at their particular combination and degree of impairment(s), over the course of twelve weeks. The exercises will be taught and progressed by an experienced physiotherapist, with reference to a "menu" of agreed exercises for each of the impairments, over the course of six fortnightly home visits, alternating with six fortnightly telephone calls. Primary outcome measures will be isometric quadriceps strength, knee flexion range of motion, timed single-leg standing balance and the "Four Balance Test Scale" at 12 weeks. Key secondary outcome measures will be self-reported levels of pain, stiffness and difficulties with day-to-day functional tasks (WOMAC). Outcome measures will be taken at three time-points (baseline, six weeks and twelve weeks) by a study nurse blinded to the exercise status of the participants. Discussion: This study (TargET-Knee-Pain) is the first step towards exploring whether an impairment-targeted approach to exercise prescription for older adults with knee pain may have sufficient efficacy to warrant further testing. If warranted, future randomised clinical trials may compare this approach with more traditional one-size-fits-all exercise approaches. Trial registration: Current Controlled Trials ISRCTN61638364.

Patellofemoral osteoarthritis (PFOA) is a common form of knee OA in middle and older age, but its relation to PF disorders and symptoms earlier in life is unclear. Our aim was to conduct a systematic review to investigate the strength of evidence for an association between anterior knee pain (AKP) in younger adults and subsequent PFOA.

Background and Purpose: Knee pain is a common disabling condition for which older people seek primary care. Clinicians depend on the history and physical examination to direct treatment. The purpose of this study was to examine the associations between simple physical examination tests and self-reported physical functional limitations.Subjects and Methods: A population sample of 819 older adults underwent a standardized physical examination consisting of 24 tests. Associations between the tests and self-reported physical functional limitations (Western Ontario and McMaster Universities Osteoarthritis Index physical functioning subscale [WOMAC-PF] scores) were explored.Results: Five of the tests showed correlations with WOMAC-PF scores, corresponding to an intermediate effect (r≥.30). These were tenderness on palpation of the infrapatellar area, timed single-leg standing balance, maximal isometric quadriceps femoris muscle strength (force-generating capacity), reproduction of symptoms on patellofemoral compression, and degree of knee flexion. Each of these tests was able to account for between 7% and 13% of the variance in WOMAC-PF scores, after controlling for age, sex, and body mass index. Three of these tests are indicative of impairments that may be modifiable by exercise interventions.Discussion and Conclusion: Self-reported physical functional limitations among older people with knee pain are associated with potentially modifiable physical impairments that can be identified by simple physical examination tests.

Pain in the hand affects an estimated 12–21% of the population, and at older ages the hand is one of the most common sites of pain and osteoarthritis. The association between symptomatic hand osteoarthritis and disability in everyday life has not been studied in detail, although there is evidence that older people with hand problems suffer significant pain and disability. Despite the high prevalence of hand problems and the limitations they cause in older adults, little attention has been paid to the hand by health planners and policy makers. We plan to conduct a prospective, population-based, observational cohort study designed in parallel with our previously reported cohort study of knee pain, to describe the course of musculoskeletal hand problems in older adults and investigate the relative merits of different approaches to classification and defining prognosis.

Background: Selective 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. Methods: Participants 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. Results: 3106 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. Conclusion: Despite 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.