General practitioners (GPs) are often consulted by patients with traumatic knee complaints. For musculoskeletal disorders, knee complaints are the second most frequent reason (after low back pain) for consulting the GP . Traumatic knee complaints are knee complaints due to a trauma of the knee or are at least of a sudden onset, and therefore likely to be traumatic. Traumatic knee complaints can be caused by e.g. bone bruise, fracture, and/or soft tissue injuries such as lesions of menisci, cruciate ligaments, collateral ligaments and muscles [2–4]. In Dutch general practice, the incidence and prevalence of knee complaints are estimated at 20 and 30 per 1000 persons/year, respectively, whereas the incidence and prevalence of traumatic knee complaints are estimated at 5.3 and 6.8 per 1000 persons/year, respectively .
For the GP, diagnosing knee injuries other than fracture or locked knee can be difficult [5–8]. Magnetic resonance imaging (MRI) of the knee can help in establishing the correct diagnosis or in excluding other diagnoses; this additional knowledge can be used to decide on subsequent treatment and/or referral of patients with traumatic knee complaints. MRI is a powerful diagnostic tool for detecting lesions of ligaments, tendons, bone, cartilage and menisci [4, 9, 10]. MRI showed a sensitivity of 86%, 91%, 76%, a specificity of 95%, 81%, 93% and an accuracy of 93%, 86%, 89% for anterior cruciate ligament, medial and lateral meniscus lesions, respectively .
Recommendations for the diagnosis and management of patients with traumatic knee complaints presenting in primary care in the Netherlands are described in the clinical guideline ‘Traumatic knee complaints’ issued by the Dutch College of General Practitioners in 2010 . At the GPs’ initial consultation an urgent referral to a medical specialist is required when there are signs of a fracture, acute locked knee, or severe complaints after patella dislocation . Otherwise, patients are managed conservatively; this generally comprises information and advice about the knee complaints, medication for pain reduction and, if indicated, referral to physical therapy. When complaints have not decreased at follow-up the GP can refer the patient to an orthopaedic surgeon who may request an MRI or perform an arthroscopy or surgery . In the Netherlands, at 1-year follow-up, 57% of patients with traumatic knee complaints had consulted their GP more than once, about one third was referred to physical therapy, and 21% were referred to an orthopaedic surgeon .
Direct referral to MRI might be a valuable tool for GPs in making appropriate and informed decisions . Negative MRI findings may enable the GP to reassure patients, treat them conservatively, and avoid unnecessary orthopaedic referrals. Positive MRI findings could confirm the GP’s diagnosis and the decision to either advise conservative treatment or refer to an orthopaedic surgeon in an earlier stage .
The DAMASK trial showed that an MRI referral by the GP prior to a provisional orthopaedic appointment yielded significant benefits in patients’ knee-related quality of life when compared with direct referral to an orthopaedic surgeon . Another study showed that early MRI of the knee in patients in secondary care with suspected internal derangement facilitates faster diagnosis at a comparable cost level compared with physical therapy; at 3-months follow-up patients randomised for an early MRI reported significantly less pain, less activity limitations and better patient satisfaction .
Whether MRI of the knee should enter the diagnostic pathway in primary care, through direct access by GP’s, depends on whether it improves patient outcomes, reduces costs and affects subsequent diagnosis and management. The objectives of this study over a period of 12 months follow-up are:
To assess the cost-effectiveness of MRI referral by the general practitioner compared to usual care in patients with persistent traumatic knee complaints.
To assess if MRI referral by the general practitioner is noninferior compared to usual care in patients with persistent traumatic knee complaints regarding self-reported knee related daily function.