KSSTA - 2026-08-27 - Journal Article
Progressive lateral femoral condyle lengthening in total knee arthroplasty produces dose-dependent increases in patellofemoral joint loading and alters patellar tracking.
Shatrov J, Boudali M, Abe K, Parker D, Walter W, Clarke E
Topics
Key Takeaway
Lateral femoral condyle distalisation of +4.5 mm increases patellofemoral reaction force by 36% during passive flexion (55.98 N to 76.30 N, p=0.006) in a dose-dependent manner.
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Summary
This cadaveric study examined whether progressive lateral femoral condyle distalisation (0, +2.5 mm, +4.5 mm) alters patellofemoral kinematics and kinetics in cruciate-retaining TKA using optical tracking and thin-film pressure sensors during passive flexion and simulated stair descent. PFJ reaction force increased significantly with each increment of distalisation during both tasks (p=0.006), with medial and lateral facet loads rising proportionally. Anterior patellar translation and external rotation increased in all resurfaced states versus native, but mediolateral translation, superior-inferior translation, and valgus-varus rotation were unaffected.
Key Limitation
Eight specimens are insufficient to detect clinically meaningful subgroup differences or control for native patellar morphology variation, limiting generalizability of the kinematic findings.
Original Abstract
PURPOSE
To examine the biomechanical effects of progressive lateral femoral condyle lengthening on patellofemoral joint (PFJ) kinematics and kinetics following total knee arthroplasty (TKA), and to determine whether lateral condyle distalisation produces measurable, dose-dependent alterations in PFJ loading and patellar tracking.
METHODS
Eight fresh-frozen cadaveric knees were implanted with a cruciate-retaining TKA and tested in four states: Native (unresurfaced), Neutral (resurfaced to native thickness), medium (+2.5 mm distalisation) and Maximum (+4.5 mm distalisation). PFJ kinematics were recorded during passive flexion and simulated stair descent using optical tracking. PFJ kinetics were measured using calibrated thin-film pressure sensors (Neutral, Medium, Maximum).
RESULTS
Progressive lateral condyle distalisation produced a significant, dose-dependent increase in PFJ reaction force during both passive flexion (Neutral: 55.98 ± 32.33 N; Maximum: 76.30 ± 46.19 N; p = 0.006) and stair descent (Neutral: 42.19 ± 28.84 N; Maximum: 55.72 ± 28.02 N; p = 0.006). Medial and lateral facet loads increased with distalisation. Kinematically, significant increases in anterior patellar translation and external rotation were observed in all resurfaced conditions compared with the native state (p < 0.05, Holm-corrected). Medial-lateral translation, superior-inferior translation, patellar flexion and valgus-varus rotation were not significantly affected.
CONCLUSION
Lateral femoral condyle lengthening in TKA increases PFJ reaction forces and alters patellar tracking in a dose-dependent manner. These findings highlight lateral condyle distalisation as a modifiable surgical factor with important implications for femoral component preparation and alignment philosophy in TKA.
LEVEL OF EVIDENCE
Level IV, controlled laboratory study.