Table 2.

Summary of findings of literature review on total knee arthroplasty (TKA) and factors affecting patellar tracking

Factor		TKA tested	Findings	Clinical relevance
Pre-existing patellar maltracking			None new	N/A
Femoral bony cuts		Scorpio Genesis II PFC Sigma RP Mathys TC	No difference between MB & FB ↑ Femoral ER → abnormal TF kinematics ↑ Femoral ER → ↓ PF stress No effect on tilt or displacement by femoral rotation	Interesting Avoid excessive femoral ER Not generalizable Not generalizable
Femoral implant design		Kinemax & Triathlon Triathlon CR/CS/PS	No effect from change of trochlea No differences in patellar tracking or pressure between the three designs	Interesting Interesting
Femoral	Flexion	PFC Sigma CR FB	Femoral flexion → lateral patellar shift	? ↑ LR rates when implant flexed
	Valgus	Not reported	Valgus → ↑ patellar stress	Interesting
	Mediolateral	LCS RP	Medial position had better outcome	Not generalizable
Tibial	Rotation	Not reported	Maximizing coverage → internal rotation of tibial implant	Useful
	Slope	Sigma CR FB	1 mm change in epicondylar distance	No significant effect
Patellar		Scorpio/ PFC Sigma/ Optetrak	No difference in KSS scores at 1 year	Interesting
Patellar thickness		Genesis II Not stated PFC Sigma	↑ patellar tilt and shift at +6 mm ↓ knee flexion at +8 mm	Unlikely to overstuff by 6 mm

Note. ER, external rotation; IR, internal rotation; MB, mobile bearing; FB, fixed bearing; CR, cruciate retaining; CS, condylar stabilized; PS, posterior stabilized; LR, lateral retinacular release; TF, tibiofemoral; N/A, not applicable; KSS, Knee Society Score; →, leads to.