This is a protocol for a Cochrane Review (prognosis). The objectives are as follows:

We will examine four prognostic factors for return to work that can be used to manage patient expectations, enhance shared decision-making, and improve timely, multidisciplinary, work-directed care.

The research question

Which of the following four prognostic factors, categorised according to the International Classification of Functioning, Disability and Health (ICF) framework, are associated with return to work after primary knee arthroplasty in patients with a paid job: type of arthroplasty (health condition), sick leave before surgery (participation), physically demanding work (environmental factors), and patient expectations regarding return to work (personal factors)?

PICOTS

We define our PICOTS as (Riley 2019):

• Patients (P): individuals engaged in paid employment who actively choose primary total knee arthroplasty or unicondylar knee arthroplasty as a treatment option for knee osteoarthritis.

• Index prognostic factors (I): we will consider these prognostic factors.

  • Type of arthroplasty

  • Duration of sick leave prior to surgery

  • Engagement in physically demanding work

  • Person's expectations regarding recovery

• Comparator (C):

  • Type of arthroplasty: unicondylar knee arthroplasty versus total knee arthroplasty

  • Duration of sick leave prior to surgery: short-term versus long-term

  • Engagement in physically demanding work: light versus medium and heavy knee-demanding work

  • Patient expectations regarding recovery: positive versus negative

• Outcomes (O): the primary outcome is the return to work, which is further classified by:

  • Nature of return to work: initial, full, or undefined;

  • Method of measurement:

    • Dichotomous (yes/no): short- and long-term return to work;

    • Scale: duration of return to work.

• Time (T): prognostic factors will be assessed preoperatively. The outcome, i.e. return to work, is measured as dichotomous data (short- and long-term) and on a scale.

  • Short-term (≤ 6 months post-surgery)

  • Long-term (> 6 months but not exceeding 36 months post-surgery)

  • Duration until return to work

• Setting (S): range of hospitals and clinics, social security and healthcare systems from multiple countries