Diagnosis and epidemiology of winged scapula in breast cancer patients: A systematic review and meta-analysis.

Background: Winged scapula (WS) is a critical complication of axillary surgery in patients treated for breast cancer, and is associated with pain, impairment of the upper extremity's function and poor performance in daily activities.

Sources of data: A systematic review and meta-analysis were performed following the PRISMA guidelines. Two independent reviewers searched PubMed, Embase and Virtual Health Library databases from January 1, 2000 to December 1, 2020. Clinical studies evaluating the diagnosis and epidemiology of WS among breast cancer surgery (BCS) patients were included.

Areas of agreement: The diagnosis of WS relies almost entirely on physical assessment. Studies have suggested a high variability in the report of the incidence of WS given the subjectivity of its diagnosis, and the different criteria used during clinical assessment.

Areas of controversy: The diagnosis of WS in BCS patients remains a challenge given the lack of standardized diagnostic protocols. Physical examination cannot rely on one manoeuvre only, as it may overlook patients with subtle injuries or overweight and contributing to the underreporting of its incidence.

Growing points: BCS patients undergoing axillary lymph node dissection experience a significantly higher incidence of WS than those undergoing sentinel lymph node dissection. The global incidence of WS after BCS is 16.79%. Additionally, the anterior flexion test and the push-up test are the most commonly performed diagnostic manoeuvers.

Areas timely for developing research: Further studies should aim for objective diagnostic tests, especially when the condition is not evident.