There are no official guidelines to assist in answering this question. I will search for relevant research papers instead.
From the Research
Indications for 3-Phase Bone Scan
- A 3-phase bone scan is used to assess patellar vascularity in total knee replacement (TKR) surgeries, particularly after lateral release 1.
- The scan can help identify patellar hypovascularity, which is associated with lateral retinacular release (LR) and other surgical procedures that can compromise patellar viability 1.
Chronic Displaced Patella Fracture after TKR
- Patellar fractures after TKR are infrequent, with a prevalence of 0.68% 2.
- The management of patellar fractures after TKR can be challenging, and treatment is guided by the integrity of the extensor mechanism, fixation status of the patellar implant, and quality of the remaining bone stock 2.
- There is no direct evidence to suggest that a 3-phase bone scan is indicated for chronic displaced patella fracture after TKR in the absence of suspected infection.
Usefulness of 3-Phase Bone Scan in Evaluating Pain after TKR
- A 3-phase bone scan has a limited role in evaluating pain in the knee region after TKR, with a positive predictive value of 2.53% and a negative predictive value of 100% 3.
- The scan may be useful in situations where abnormal serology is present, but repeated joint aspirations samples are inconclusive 3.
Patellar Fractures after TKR
- Patellar fractures after TKR can occur, with a diverse range of fracture patterns, including transverse, comminuted, vertical, and avulsion fractures 4.
- The incidence of patellar fractures after TKR is 1.14%, with a mean time to fracture of 17.5 months 4.
- Treatment of patellar fractures after TKR is guided by the presence of symptoms, disruption of the extensor mechanism, and the quality of the remaining bone stock 2, 4.