Table 1.

Disadvantages of RCTs and advantages of OESs, determined by the characteristics of longitudinal evaluation in patients with prosthetic joint replacements (PJRs).

Characteristics of the evaluation in PJR	RCTs (disadvantages)	OESs (advantages)
Permanent implants (unlimited follow-up)	Expensive studies with restrictive inclusion criteria and difficulty to follow-up an unlimited number of patients and procedures	Lower cost for long-term follow-up and possibility of including of an unlimited number of patients and procedures
Low-frequency if complications and significant prevalence in long-term follow-up
High number of patients and procedures
Real-world view, with different centers and surgeons involved (external validation)	Centers of excellence Few surgeons involved Report the reality of the institution (limited generalization)	Participation of a large number of centers and surgeons (generalization is possible)
Cross-sectional evaluations (survival curves)	Unusual practice (predetermined periods)	Usual practice (longitudinal-to-endpoint)
Number of exposure factors and outcomes (simultaneous)	Limited	Multiple

RCTs, controlled and randomized controlled trials; OESs, observational epidemiological studies.