Abstract：
BACKGROUND: 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).
CONCLUSIONS: 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.
METHODS: III.
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).
CONCLUSIONS: 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.
METHODS: III.
摘要：
背景：关于胫骨-股关节线的髌骨低位置有两种变体：髌骨baja（PB）和假髌骨baja（PPB）。本研究的目的是调查一组因无菌原因接受翻修全膝关节置换术（rTKA）的患者中PB和PPB的发生率，并描述每组ROM的差异。
方法：这项回顾性研究包括了在2017年至2022年间接受无菌翻修TKA手术的114例患者。对患者进行僵硬（第1组）或无菌性松动/不稳定（第2组）。Insall-Salvati比率（ISR）和Blackburne-Peel比率（BPR）用于评估髌骨位置。ISR<0.8定义PB,而ISR≥0.8和BPI<0.54的病例被定义为PPB。测量ROM并进行亚分析以研究ISR和BPR值的进展。
结果：55例患者包括第1组，59例患者包括第2组。总的来说,rTKA前有PB13例(11.4%)，rTKA后有PB24例(21%)。rTKA前PPB病例为13例（11.4%），rTKA后为34例（29.9%）。第1组患者在rTKA前后表现出更多的PB（分别为12.8％vs10.2％和27.3％vs15.2％）。然而,rTKA后，第1组患者的PPB（20％）低于第2组（39％）（p=0.02）。在第1组中，rTKA后PPB患者的ROM少于无PPB患者[83.2（±21.9）vs102.1（±19.9）（p=0.025）]。亚分析（69例）显示，在rTKA之前和之后，ISR有统计学意义的下降（p=0.041），从天然膝关节到rTKA后（p=0.001）。在rTKA之前和之后（p=0.001）以及从天然膝关节到rTKA之前和之后（p<001），BPR均有统计学上的显着降低。
结论：接受rTKA后，髌骨baja（PB）和假性髌骨baja（PPB）的发生率均增加。膝关节的僵硬度与较高的PB发生率有关，而非僵硬病例显示PPB的发生率明显较高。rTKA术后膝盖僵硬和PPB的患者的运动范围（ROM）显着降低。此外,研究显示,每次后续手术后,ISR和BPR均显著下降.这些信息对医疗保健提供者至关重要，因为它揭示了RTKA的潜在风险和结果，允许改善患者管理和手术决策。
方法：III.
方法：这项回顾性研究包括了在2017年至2022年间接受无菌翻修TKA手术的114例患者。对患者进行僵硬（第1组）或无菌性松动/不稳定（第2组）。Insall-Salvati比率（ISR）和Blackburne-Peel比率（BPR）用于评估髌骨位置。ISR<0.8定义PB,而ISR≥0.8和BPI<0.54的病例被定义为PPB。测量ROM并进行亚分析以研究ISR和BPR值的进展。
结果：55例患者包括第1组，59例患者包括第2组。总的来说,rTKA前有PB13例(11.4%)，rTKA后有PB24例(21%)。rTKA前PPB病例为13例（11.4%），rTKA后为34例（29.9%）。第1组患者在rTKA前后表现出更多的PB（分别为12.8％vs10.2％和27.3％vs15.2％）。然而,rTKA后，第1组患者的PPB（20％）低于第2组（39％）（p=0.02）。在第1组中，rTKA后PPB患者的ROM少于无PPB患者[83.2（±21.9）vs102.1（±19.9）（p=0.025）]。亚分析（69例）显示，在rTKA之前和之后，ISR有统计学意义的下降（p=0.041），从天然膝关节到rTKA后（p=0.001）。在rTKA之前和之后（p=0.001）以及从天然膝关节到rTKA之前和之后（p<001），BPR均有统计学上的显着降低。
结论：接受rTKA后，髌骨baja（PB）和假性髌骨baja（PPB）的发生率均增加。膝关节的僵硬度与较高的PB发生率有关，而非僵硬病例显示PPB的发生率明显较高。rTKA术后膝盖僵硬和PPB的患者的运动范围（ROM）显着降低。此外,研究显示,每次后续手术后,ISR和BPR均显著下降.这些信息对医疗保健提供者至关重要，因为它揭示了RTKA的潜在风险和结果，允许改善患者管理和手术决策。
方法：III.
