Diagnosing knee osteoarthritis in patients, differences between general practitioners and orthopedic surgeons: a retrospective cohort study

BACKGROUND: knee complaints are one of the most common reasons to consult the general practitioners in the Netherlands and contribute to the increasing burden on general practitioners. A proportion of patients that are referred to orthopedic outpatient clinics are potentially referred unnecessarily. We believe osteoarthritis is not always considered by general practitioners as the cause of atraumatic knee complaints. This may impede early recognition and timely care of osteoarthritis complaints and lead to unnecessary referrals. METHODS: the aim of this study was to compare the frequency of (differential) diagnosis of osteoarthritis mentioned in referral letters of general practitioners with the frequency of osteoarthritis mentioned as orthopedic diagnosis at the outpatient clinic. Therefore we conducted a retrospective cohort study based on data collected from referral letters and the corresponding outpatient clinic reports of patients with atraumatic knee complaints of 45 years or older referred to a regional hospital in Nijmegen, The Netherlands in the period from 1-6-2019 until 1-01-2020. RESULTS: a total of 292 referral letters were included. In the younger aged patients (45–54 years) osteoarthritis was mentioned less frequent and meniscal lesions were mentioned more frequent in referral letters when compared to diagnoses made at the outpatient clinic. Differences in differential diagnosis of osteoarthritis as well as meniscal lesions between orthopedic surgeon and general practitioners were found (both p < 0.001, McNemar). Matching diagnoses were present in 58.2% when all referral letters were analyzed (n = 292) and 75.2% when only referrals containing a differential diagnosis were analyzed (n = 226). Matching diagnoses were present in 31.6% in the younger age categories (45–54 years). A linear trend showing fewer matching diagnoses in younger patient categories was observed (p < 0.001). CONCLUSIONS: Osteoarthritis was less frequently mentioned in general practitioner referral letters among the differential diagnosis then it was diagnosed at the outpatient clinic, especially in younger patients (45–54 years). Also matching diagnoses in younger patients were evidently lower than in older patients, partly explained by underdiagnosing of osteoarthritis in younger patients in this cohort. Better recognition of osteoarthritis in younger patients and changing the diagnostic approach of general practitioners might improve efficacy in knee care. Future research should focus on the effectiveness of musculoskeletal triage, the need for multidisciplinary educational programs for patients and promotion of conservative treatment modalities among general practitioners.