Effects of patellar replacement and height on treatment outcomes of total knee arthroplasty / 中华骨科杂志

ABSTRACT

Objective:To investigate the effect of patellar replacement and patellar height on the therapeutic effect of total knee arthroplasty (TKA).Methods:A retrospective analysis was conducted on 429 patients (92 males, 337 females; aged 66.81±7.05 years; left=226, right=203) with severe knee osteoarthritis who underwent TKA in the First Affiliated Hospital of Shandong First Medical University from July 2020 to December 2021, with the body mass index of 27.60±4.22 kg/m 2, Grade-III Kellgren-Lawrence, and Insall-Salvati (IS) ratio >0.8. Afterward, the patients were divided into 4 groups according to whether patellar replacement was performed or not and the preoperative IS ratio (IS of 0.8-1.2 for normal patellar and >1.2 for high patellar): the patellar replacement+normal height patellar group (263 cases), the patellar replacement+high height patellar group (66 cases), the patellar non-replacement+normal height patellar group (68 cases), and the patellar non-replacement+high height patellar group (32 cases). Moreover, postoperative intergroup IS ratio, Knee Society Score (KSS), Hospital for Special Surgery (HSS) knee score, Oxford Knee Score (OKS), knee range of motion, complications, and satisfaction were analyzed. Results:All patients were followed up, and the time was 1.15±0.16 years (range, 1-2 years). Postoperative symptoms such as knee pain, swelling, and limitation of movement were significantly improved compared with the preoperative period. Additionally, KSS pain score, knee range of motion, HSS score and OKS score were significantly different among the four groups ( F=9.49, P<0.001; F=11.09, P<0.001; F=6.74, P<0.001; F=3.24, P=0.022), but the difference in KSS functional scores was not statistically significant ( F=1.84, P=0.140). At the same time, the KSS pain score, HSS score, OKS score, and knee range of motion (41.84±5.25, 80.43±6.99, 14.27±5.39, and 122.33°±4.93°) in the patellar replacement+normal height patella group were all better than those in the patellar non-replacement +normal height patella group (38.31±7.31, 77.00±7.81, 16.05±5.81, 120.99°±4.90°) and patella non-replaced + high height patella group (37.97±7.28, 75.62±11.02, 16.63±6.67, 116.25°±13.08°), with statistically significant differences ( P<0.05). The patella replacement+ high height patella group only had better KSS pain scores than the patella non-replaced+normal height patella group and the patella non-replaced+high height patella group (41.74±6.35, 38.31±7.31, 37.97±7.28), with statistically significant differences ( P<0.05). Moreover, Knee mobility was better in the patellar replacement+high height patella group (121.68°±2.88°) and the patellar non-replacement+normal height patella group (120.99°±4.90°) than in the patellar non-replacement+high height patella group (116.25°±13.08°), and the differences were statistically significant ( P<0.05). There were statistically significant differences in the IS ratio before surgery, 1 day after surgery and 1 year after surgery among the four groups ( P<0.05), and the IS ratio at 1 day after surgery was lower than that before surgery with statistically significant differences ( P<0.05), but there was no statistically significant difference between the IS ratio at 1 year after surgery and that before surgery ( P>0.05).Furthermore, the preoperative differences in the incidence of anterior knee pain, patellar clicking and satisfaction rates in patients with different patellar heights were not statistically significant ( P>0.05). Finally, the patellar replacement group possessed a lower incidence of anterior knee pain (normal height patella: 7.6% vs. 16.2%, χ 2=4.68, P=0.031; high height patella: 9.1% vs. 25.0%, χ 2=4.46, P=0.035) and patellar clicking (normal height patella: 9.1% vs. 17.6%, χ 2=4.05, P=0.044; high patella: 13.6% vs. 31.2%, χ 2=4.28, P=0.039); there was no significant difference in satisfaction rate among the four groups after operation ( P>0.05). Conclusion:Postoperative outcomes were better in patients with patellar replacement during TKA than in patients with no patellar replacement, and knee range of motion was better in patients with normal-height patellas than in patients with high patellas preoperatively, with no effect of TKA on patellar height.