Incidence of patella baja and pseudopatella baja in aseptic revision total knee arthroplasty

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发表日期：

2024年3月15日

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Dimitrios A. Flevas,
Marco Brenneis,
Thomas Bauer,
Eric Bogner,
Mathias Bostrom,
Michael Cross,
Mark Figgie,
Steven Haas,
Lionel Ivashkiv,
Seth Jerabek,
Kethy Jules-Elysee,
Meghan Kirksey,
Matthew Koff,
Maxwell Konnaris,
Samantha Lessard,
David Mayman,
Alexander McLawhorn,
Piali Mukherjee,
David Oliver,
Miguel Otero,
Douglas Padgett,
Tania Pannellini,
Giorgio Perino,
Alessandra Pernis,
Hollis Potter,
Scott Rodeo,
Brennan Rourke,
Tannin Schmidt,
Thomas Sculco,
Purva Singh,
Kathleen Tam,
Chloe Verwiel,
Geoffrey Westrich,
Timothy Wright,
Mark Youssef,
Allina Nocon,
Ioannis Gkiatas,
Wali Pirzada,
Georgios Tsakotos,
Peter K. Sculco

摘要

Introduction

There are two variants regarding the low location of the patella in relation to the tibio-femoral joint line: patella baja (PB) and pseudo-patella baja (PPB). The purpose of this study is to investigate the incidence of PB and PPB in a cohort of patients that underwent revision total knee arthroplasty (rTKA) for aseptic reasons and describe any differences in each group’s ROM.

Methods

This retrospective study included 114 patients that underwent aseptic revision TKA surgery between 2017 and 2022. Patients were revised either for stiffness (Group 1) or aseptic loosening/instability (Group 2). The Insall-Salvati ratio (ISR) and Blackburne-Peel ratio (BPR) were used to evaluate the patellar position. ISR < 0.8 defined PB, while cases with ISR ≥ 0.8 and BPI < 0.54 were defined as PPB. ROM was measured and a subanalysis was conducted to investigate the progression of the values of ISR and BPR.

Results

55 patients comprised Group 1, and 59 patients comprised Group 2. Overall, 13 cases (11.4%) had PB before rTKA and 24 (21%) had PB after rTKA. Cases with PPB were 13 (11.4%) before and 34 (29.9%) after rTKA. Group 1 patients presented with more PB before and after rTKA (12.8% vs 10.2% and 27.3% vs 15.2% respectively). However, after rTKA Group 1 patients presented with less PPB (20%) compared to Group 2 (39%) (p = 0.02). In Group 1, patients with PPB after rTKA had less ROM compared to those without PPB [83.2 (± 21.9) vs 102.1 (± 19.9) (p = 0.025)]. The subanalysis (69 patients) showed a statistically significant decrease in ISR before and after rTKA (p = 0.041), and from the native knee to post-rTKA (p = 0.001). There was a statistically significant decrease in BPR before and after rTKA (p = 0.001) and from the native knee to both pre- and post-rTKA (p < 001).

Conclusion

After undergoing rTKA, the incidences of both patella baja (PB) and pseudo-patella baja (PPB) increased. Stiffness in the knee was associated with a higher incidence of PB, while non-stiffness cases showed a significantly higher incidence of PPB. Patients with stiff knees and PPB after rTKA experienced a significant reduction in range of motion (ROM). Additionally, the study revealed a noteworthy decrease in ISR and BPR with each subsequent surgery. This information is crucial for healthcare providers, as it sheds light on potential risks and outcomes of rTKA, allowing for improved patient management and surgical decision-making.

Level of evidence

III.