Consultation patterns of children and adolescents with knee pain in UK general practice: analysis of medical records

Musculoskeletal problems are one of the leading causes of years lived with disability and are associated with significant individual, social and financial burden worldwide [1]. While there is extensive research into musculoskeletal problems in adults, our current understanding of the epidemiology, burden and treatment of musculoskeletal problems in children and adolescents is much more limited [2, 3]. Surveys show that up to 50% of children and adolescents report musculoskeletal pain in any 1 month, and while many of these conditions are assumed to be self-limiting, as many as 50% of this population will experience chronic or recurrent pain [4, 5]. The impact of musculoskeletal pain on children and adolescents can extend beyond their normal daily routine of school, social and sports participation, and result in medication use, health care seeking and substantial health care costs [6‐9].

General practitioners (GP) are usually the first to assess, treat and manage children with musculoskeletal problems. Nationally representative data from Australia, Spain and the UK suggest that the annual consultation prevalence of musculoskeletal problems in children and adolescents is between 4 and 8% [7, 10, 11]. These studies consistently identified lower limb problems, in particular foot and knee problems, to be the most common body sites children consulted their GP about, regardless of age group or sex. Interestingly, knee problems were the only body region for which boys were consistently more likely to consult than girls [7, 10, 12]. While this suggests that there is a difference in consultation rates between boys and girls repeat consultations are often discounted in these studies and they do not provide any information as to the actual clinical caseload (i.e. total number of consultations) knee problems in children and adolescents have for GPs and it is not known whether the same sex trends would be identified. Considering the poor long-term prognosis of knee pain in this population it is particularly important to account for repeat consultations and the impact these have on GPs clinical caseload.

There is currently limited evidence and understanding about the general population prevalence of healthcare consultations for knee problems by children and adolescents in general practice and the characteristics of these consultations. This includes uncertainty as to how consultations are recorded by GPs (i.e. use of a specific diagnosis code that can explain a patients presenting problem e.g. ‘patella dislocation’, compared to a non-specific symptom code that provides no information on the diagnosis or cause of the problem e.g. ‘knee pain’), the extent to which knee problems are diagnosed by GPs and, whether recording of consultations vary for patients of differing age, sex or socio-economic deprivation. Such information may be important in term of the implications for patient’s management in primary care and their prognosis. The diagnosis of knee problems is often a challenge for health practitioners for a number of reasons including non-specific symptoms such as ‘knee pain’ being commonly reported by patients and indicative of a wide range knee problems and clinical tests either being of limited diagnostic value or not available (e.g. ‘patellofemoral pain’ is a common condition in adolescents and is based on a ‘diagnosis of exclusion’) [13‐15]. The way in which GPs code consultations for example using a symptom code such as ‘knee pain’ or specific diagnosis code such as ‘patella dislocation’ has previously been explored in adults with patellofemoral disorders [16‐18]. This study found that symptom codes, rather than specific diagnosis codes, were more commonly used by GPs regardless of age but whether or not this finding also applied to children and adolescents, a population in whom lower limb injury is more common [19], is yet to be determined. An improved understanding of the epidemiology of consultations for knee problems in children and adolescents can inform training and assessment priorities in general practice, identify gaps in service availability [20], explore the extent to which GP’s diagnose knee problems in children and adolescents, identify groups of people who consult more frequently and inform the development of new and novel intervention and preventative strategies. The aim of this study was to describe the epidemiology of consultations for knee problems that children and adolescents aged between 3 and 19 years consult for in general practice. Specifically, this study aims to report on how consultations for knee pain are recorded by GPs for this population, and examine the patterns of Read codes used (symptom or diagnostic Read code) for both patient presentations and the number of consultations, stratified by age group, sex and area of socio-economic deprivation.

This study describes the epidemiology of consultations by children and adolescents who present to general practice with a knee problem. The patterns of Read codes used are reported for both patient presentations and the number of consultations, stratified by age group, sex and socio-economic deprivation. In the context of all musculoskeletal consultations by children and adolescents, the findings indicate that knee problems are the fourth most common reason for a patient to consult, and involve the second highest number of consultations, accounting for approximately 10% of the childhood musculoskeletal caseload for GPs. The results of this study show that GPs infrequently use specific diagnostic Read codes to record consultations for knee problems; however this practice differs dependent on demographic factors such as the patient’s age, sex, and by area of socio-economic deprivation. This may highlight differences in GPs diagnosis patterns and reflect GPs diagnostic uncertainty when recording consultations (e.g. a higher proportion of symptom codes used to record consultations for younger children compared to older children) or indicate that there are differences in the knee problems that children and adolescents consult for based on these socio-demographic factors and further research is needed to explain these findings.

This study provides insight into how child and adolescent patient presentations and consultations for knee problems are recorded by GPs in the UK, and how this varies by demographic and socio-economic factors. Strengths of this study include the use of routinely recorded data from eleven general practices including every patient aged between 3 and 19 years who consulted their GP about a knee problem in 2010. Patient presentations and consultations in this study mirror the reported onset of knee problems by age in other studies (e.g. the reported high point prevalence in adolescents between 12 and 17 years of age has been reported elsewhere [8, 37]). Compared to previous work that describes consultations for lower limb problems by children and adolescent in primary care [7, 26], this current study reports on knee problems specifically and the range of problems children and adolescents consult their GP about, as well as describes the consultation patterns for knee problems in terms age, sex and socio-economic deprivation. In addition this information informs on overall patient presentations for knee problems and describes GP’s overall clinical load. The sample used in this current study is large and representative of the child and adolescent general practice population in the UK, given that over 95% of the UK population are registered with a general practice. Furthermore CiPCA has demonstrated comparability to other national UK general practice databases [21] as well as international databases.

These findings do need to be interpreted in the context of several limitations. While Read codes provide GPs with a structured way in which to record patient consultations, interpretation is limited for two reasons. Firstly, the way in which GPs assess and diagnose patients and record consultations is not standardised (e.g. through the consistent use of a diagnostic classification system), and is likely to lead to variations in how problems are recorded by different GPs [21, 38]. Therefore, it is not currently known if the patterns identified reflect differences in patient presentations or the coding practices of GPs. Secondly, Read codes do not provide any information as to the mechanism of injury or aetiology of the presenting problem or characteristics of the pain presentation (e.g. pain severity, duration, number of pain sites). In terms of socio-economic deprivation, an IMD score was calculated for each individual patient based on their home postcode. While the IMD score is the most useful and commonly used small area measure of deprivation, actual household deprivation is not known (e.g. family income) and within every area there will be individuals who are more deprived and individuals who are not [31]. Lastly, only a small number of consultations were recorded using ‘diagnosis: non-trauma’ codes thereby limiting the identification of trends and conclusions that could be made. The infrequent use of ‘non-trauma’ codes could be a result of the categorisation of Read codes by authors or the way that these codes are used by GPs. The authors were found to have ‘good’ agreement in categorising Read codes, with discrepancies noted for only a few Read codes which have multiple variations for the same code e.g. ‘recurrent dislocation’ and ‘derangement of the knee’. Of the 375 knee codes 105 were categorised by the two authors as non-trauma codes. This suggests that while there are a large number of non-trauma codes available either these conditions are not commonly seen by GPs, the criteria for their use is unclear or that these codes are only used when there is diagnostic certainty and until which time symptom codes may be used.

In many countries including the UK, GPs are first contact practitioners, responsible for diagnosis, treatment, management, and referral of patients for further investigations and healthcare services where necessary. This study identified that symptom codes were most commonly used by GPs to record consultations for knee problems in children and adolescents. Possible reasons for the frequent use of symptom codes include factors related to GPs and their ability to assess and diagnose musculoskeletal conditions, diagnostic uncertainty, knowledge and availability of treatments, time pressures, their own beliefs about paediatric pain, the value and selection of Read codes and continuity between practitioners, and potential stigma associated with a diagnostic ‘label’ [39]. Lastly, many GPs may actively be taking a ‘wait and see’ approach to see if symptoms resolve or a more clear diagnosis evolves through repeat consultations. The ‘coding culture’ has previously been explored in a qualitative study of anxiety and similar work could be conducted in musculoskeletal conditions to better understand how GPs code these conditions and in patients of various ages [39]. The use of diagnosis codes were found to increase with age, and were more frequently used for boys. These findings are likely to reflect true differences in the problems patient’s consult for as previous studies that have identified both increasing age and male sex to be associated with increased injury rates due to a variety of mechanisms including sport, traffic accident, and collision with or being struck by another object [40‐42]. The increased use of diagnosis codes in these groups may also reflect improved communication abilities with age and may indicate increased injury severity especially for boys e.g. increased incidence of fractures. These finding combined suggest that the risk factors for age and sex vary and that these need to be considered when developing and targeting prevention strategies. The significance of the type of Read code used to record consultations for knee pain is not yet known and further work could examine whether the type of code (i.e. symptom or diagnosis code) used by GPs has any association with a patients prognosis or the way in which their condition is managed (e.g. treatments and referrals for further investigations or to other health professionals) [43].

A third of patients who consulted for a knee problem in this study (see Table 1) were found to consult on more than one occasion during the study year. For those who consulted more than once, the same Read code category (symptom, diagnosis) was used to record subsequent consultations in 90.1% of cases. This finding suggests that a substantial proportion of patients have a recurrent or persistent knee problem. Previous studies have shown that knee pain persists in a significant proportion of patients (from 33 to 90%) [44‐47]. Persistent knee pain in children and adolescents has been found to be associated with high pain intensity, low quality of life and an increased risk of ceasing all participation in sports [8, 46]. The implications of knee pain experienced during childhood and adolescents and long term health conditions (e.g. osteoarthritis) are still to be determined [48], although more recent evidence suggests an association between adolescent knee pain and patellofemoral arthritis [49]. Considering the generally poor prognosis of knee pain experienced during adolescents [46], further work is needed to identify clinically meaningful and modifiable prognostic factors that can enable the early identification of those who are at most risk of recurrent or persistent symptoms.

An interesting finding of this study was the differences in the Read code category used by GP’s to record consultations for patients from areas of high and low socio-economic deprivation, with symptoms codes (e.g. ‘knee pain’) used predominantly for children and adolescents from areas of low socio-economic deprivation and diagnosis codes (e.g. ‘knee sprain’, ‘patella dislocation’) for those from areas of high socio-economic deprivation. The relationship between socio-economic deprivation and the onset, persistence and outcomes for musculoskeletal health in children and adolescents is complex, often conflicting and currently not well understood. This is likely due to variations in study methodology, study and healthcare setting (e.g. country specific and access to healthcare), how socio-economic status defined and is measured (e.g. family level vs. area level; domains incorporated and weightings of each), the types and severity of injuries evaluated and how these are reported (e.g. all vs. stratification of injury by type). For example, a study conducted in Spanish primary care identified an association between low socio-economic status and wounds, bruises, sprains and fractures in boys and girls aged less than 15 years [50]. Similarly, a Scottish study utilising hospital fracture data found both fracture incidence and type of fracture was associated with social deprivation, with high socio-economic deprivation associated with a higher incidence of fracture and fractures occurring in the upper limb [51]. However, data from the Alberta healthcare registry found that while overall injury rates were higher in children from high socio-economic deprivation, the rate of dislocations / sprains and strains was found to vary with socio-economic status (e.g. compared to children who receive no healthcare subsidies the rate of dislocations / sprains and strains was lower in children receiving partial or total health care subsidies however higher for children receiving welfare) and no association was found for fracture [52]. Additional hypothesis driven studies are needed to clarify the relationship between socio-economic deprivation and the types, location and severity of musculoskeletal problems in children and adolescent as well as the influence socio-economic deprivation has overtime in terms of recovery, recurrence and persistence of pain. Further quantitative and qualitative work is also needed to identify the mechanisms and risk factors associated with musculoskeletal problems and how these may differ, or not, along the social gradient. For example, socio-economic deprivation appears to be associated with injuries sustained around the home and during recreation and play but not with sports-related injuries [53]. This future work would enable the identification of potentially ‘at risk populations’ and inform the development of tailored and targeted prevention strategies.

Knee problems in children and adolescents represent a significant caseload for GPs and the propensity for these problems to persist presents a significant challenge for general practice. This study described the epidemiology of GP consultations for knee problems in children and adolescents aged between 3 and 19 years and in doing so identified several avenues for future research that in time could provide GPs with an evidence-based approach to the management of these problems.