Predictors of persistent complaints after a knee injury in primary care.

Background: Prognosis of persistent complaints after knee injury is based on secondary care populations. In a primary care setting, however, no studies have addressed this issue.

Aim: To identify possible predictors of persistent complaints 1 year after a knee injury. These predictors are important for guiding the GP's therapeutic management, and giving advice to patients about work and/or sports-related activities.

Design And Setting: Primary care prospective cohort study with a 1-year follow-up period in five municipalities in the southwest region of the Netherlands.

Method: Patients who were eligible were recruited to the study by a GP research network with around 84,000 patients and 40 participating GPs. A total of 134 patients (aged 18-65 years) who consulted their GP within 5 weeks after a knee injury entered the study. Follow-up after 1 year was conducted in 122 patients. The main outcome was persistent complaints 1 year after injury; possible predictors for these complaints were obtained with a questionnaire, a physical examination, and magnetic resonance imaging (MRI), according to a standardised protocol.

Results: After 1 year, of the 122 available patients, 21 (17%) reported persistent complaints and 101 (83%) reported full recovery or major improvement. In this study being aged >40 years had a significant association (P<0.05) with persistent complaints (odds ratio 8.0, 95% confidence interval 2.1 to 30.5). Physical examination and MRI findings revealed no predictors that were associated with these complaints.

Conclusion: Being aged >40 years was the only determinant with a significant association with persistent complaints. As physical examination and MRI had no predictive value, they are not recommended for prognosis of persistent complaints.