Summary
To the authors’ knowledge, this study is the first retrospective cohort study that provides insight into the incidence of OSD in general practice as well as the different management strategies applied in this population based on longitudinal population data. An incidence of OSD of 3.8 per 1000 person–years in those aged 8–18 years was found, with a higher incidence for boys than girls. This incidence indicates that an average GP practice (255 patients aged 8–18 years total) in the Netherlands sees about one new patient with OSD per year.
In the population studied, the peak incidence was 1 year earlier in girls compared with boys. Most patients (69.3%) only visited the GP once. Most patients were managed with advice and rest at first consultation. Nevertheless, in 17.5% of the cases the GP referred the patient for imaging at first consultation despite the advice of the current Dutch general practice (NHG) guideline.32 Only 11.5% were referred to a physiotherapist.
Strengths and limitations
To the authors’ knowledge, this is the first study to examine the incidence of OSD based on medical files for a large group of patients in general practice. It gives a representative overview on the incidence and management in general practices.
GP medical records are not primarily intended for data collection and have certain limitations, for example, possible selection bias as a result of the diagnostic accuracy of the GP and dependence on reporting in the medical file by the GP.33 Moreover, technically speaking the incidence may be considered as the incidence of recorded consultations, as this study was dependent on medical files. To limit the possible underestimation of the overall incidence because of limited medical notes or non-uniform ICPC coding, multiple ICPC codes and free-text terms to identify patients with OSD were used.
In this study a maximum duration of complaint cut-off point of 18 months was used.22 In the analyses this may have led to a duplicate count of one OSD incident into two separate incidents. This could, for example, lead to a patient being referred to the orthopaedic surgeon at first consultation whereas this actually was the third consultation within a larger timeframe. The authors believe this had limited impact on the overall conclusions as this situation could only have occurred in a maximum of 26 patients. The decision to maintain the cut-off point of 18 months came from the most common belief that OSD, aside from rare instances, is not a complaint that spans multiple years.22
Lastly, 123 (23.9%) incident cases did not have at least 18 months of follow-up time. However, this is highly unlikely to have a relevant impact on the results as most patients (91.8%) had a maximum of two consultations with a median of 53 days between first and second consultation.
Comparison with existing literature
An incidence of 4.9 and 2.7 for boys and girls per 1000 person–years, respectively, was found. Currently, to the authors’ knowledge, no other incidence data for OSD are available in the literature. Similar to the findings in the current study, a previous study also showed a higher frequency of OSD in boys (15.2%) compared with girls (10.0%) in children aged 9–15 years.8 In the population in the current study, the difference in peak incidence between girls and boys was only 1 year, at 11 and 12 years of age, respectively. This is in concordance with previous literature where the occurrence of OSD was higher in boys compared with girls, but complaints presented at an earlier age in girls. This is possibly because of the earlier onset of puberty and skeletal maturation in girls.8,16,34
According to current research and the NHG guideline, OSD is a clinical diagnosis based on anamnesis and physical examination, and the management of OSD is conservative, guided by the severity of the symptoms.19,22,32,35,36 A multinational survey showed that healthcare professionals favour education and exercise therapy in the management of OSD.27 In concordance with previous literature and the NHG guideline32 most patients in this study received advice (55.1%) followed by rest (21.0%). However, most adolescents with OSD are often highly physically active, thus resting and therefore recovering may be difficult for patients.8,37
Recently, Rathleff et al investigated the effectiveness of an intervention consisting of education on activity modification and knee-strengthening exercises in 51 adolescents with OSD.38 They showed that patella tendon loading and pain management, hip and knee strengthening, and jumping exercises resulted in a self-reported improvement of 80% and 90% after 12 to 52 weeks, respectively. In the current study, patients were referred to a physiotherapist in only 13.4% of all consultations, although the actual content of the management is unknown. Despite limited evidence from the literature, personalised physical activity programmes may offer a beneficial alternative management approach to improve clinical outcomes.
The NHG guideline32 explicitly states that there is no added benefit whatsoever of imaging (X-ray or magnetic resonance imaging) and referral to an orthopaedic surgeon.39 Remarkably, overall, patients were referred for imaging or to an orthopaedic surgeon in almost 20% and 8% of all consultations, respectively. This discrepancy could be because of a lack of knowledge regarding OSD and the management of OSD by the GP, in addition to an attempt at gaining insight into the severity of the complaint or to appease the patient. Lastly, it may be a sign of the growing overutilisation of diagnostic imaging.40 The rate of referral to an orthopaedic surgeon seems to correlate with the number of consultations, as the percentage increased with each following consultation, that is, a rate of 3.3% at the first consultation and 44.4% at the fourth consultation. This is likely explained by the severity of the complaint; patients with more severe OSD will probably visit the GP more often for the complaint. Furthermore, the ineffectiveness of previous advice or management can also contribute to the GP referring to the orthopaedic surgeon to get an expert opinion.
Implications for research and practice
OSD is a common and impactful37 complaint in children and adolescents with an incidence of 3.8 per 1000 person–years. Peak incidence for boys and girls was at age 12 and 11 years, respectively. There is a discrepancy between the current NHG guideline and how GPs manage the condition in clinical practice. As OSD mostly occurs in sports-active adolescents,8,37 future research into personalised physical activity programmes may offer opportunities to make progress in effectively treating OSD in general practice. Better understanding and management of OSD, specifically for persistent cases, could decrease the number of consultations and thus the overutilisation of imaging and referral to a medical specialist.