JOA - 2026-03-23 - Journal Article
Kinematic Impact of Patella Resurfacing in Bicruciate-Stabilized Total Knee Arthroplasty: A Comparative Analysis of Femoro-Tibial Motion and Patellar Classification.
LaCour M, Smith L, Dessinger G, Chesney C, Komistek RD
Topics
Key Takeaway
Patellar resurfacing in bicruciate-stabilized TKA reduced patella baja incidence from 38% to 22% and increased lateral condylar rollback by 2.6 mm compared to unresurfaced controls.
Summary Depth
Choose how much analysis to show on this article page.
Summary
This retrospective study compared fluoroscopic weight-bearing kinematics in 167 BCS TKA patients stratified by patellar resurfacing status across six surgeons. Resurfaced patellae demonstrated significantly less patella baja (22% vs 38%, P=0.033), greater lateral condylar rollback (-14.4 vs -11.8 mm, P=0.012), greater axial rotation (9.4° vs 7.4°, P=0.043), and fewer instances of reverse axial rotation (7% vs 13%, P=0.049). Weight-bearing ROM difference (113° vs 110°) was not statistically significant.
Key Limitation
The unresurfaced cohort is less than one-third the size of the resurfaced cohort (39 vs 128), and surgeon-level resurfacing preferences were not controlled, introducing substantial confounding by indication.
Original Abstract
INTRODUCTION
Understanding patello-femoral and femoro-tibial kinematics is essential for optimizing outcomes following total knee arthroplasty (TKA). Registry data indicate higher revision rates in TKA patients who have unresurfaced patellae, yet the kinematic implications of patellar resurfacing remain underexplored. This study investigated the influence of patellar resurfacing on patellar height classification and knee kinematics.
METHODS
A retrospective observational study of 167 Bicruciate-Stabilized (BCS) TKA patients who were from six surgeons was evaluated-128 with resurfaced and 39 with unresurfaced patellae. Subjects underwent fluoroscopic analysis during weight-bearing deep knee bends. Femoro-tibial kinematics, including antero-posterior condylar motion and axial rotation, were assessed via three-dimensional model-fitting. Patellar height was classified using the Blackburne-Peel ratio at 30° flexion.
RESULTS
The resurfaced cohort exhibited a lower incidence of patella baja (22%) and alta (2%) compared to the unresurfaced group (38 and 5%, respectively), with patella baja significantly more common in the unresurfaced group (P = 0.033). The resurfaced group also demonstrated more lateral condylar rollback (-14.4 ± 5.4 versus -11.8 ± 5.6 mm, P = 0.012) and greater overall axial rotation during flexion (9.4 ± 5.4 versus 7.4 ± 5.8°, P = 0.043), with fewer instances of reverse axial rotation (7 versus 13%, P = 0.049). Finally, resurfaced knees had marginally greater weight-bearing range-of-motion (113 ± 16.9 versus 110 ± 10.8°, P = 0.369), though not statistically significant.
CONCLUSION
This study suggests that patellar resurfacing in BCS TKA may contribute to more favorable patellar height classifications, more natural kinematics, and reduced incidences of reverse rotation. The observed trends highlight the potential of resurfacing in achieving improved TKA kinematics, although variability in surgeon technique and lack of preoperative data limit the generalizability of these results.