Influence Of Patella Height On Knee Joint Function After Total Knee Arthroplasty

Objective:To measure the changes of patella height before and after total knee arthroplasty,and to explore the correlation between the variety of patella height and postoperative knee joint clinical function,range of motion,subjective satisfaction and patellar crepitus.Materials and methods:Between August 2019 and January 2022,116 patients who underwent total knee arthroplasty in Department of Orthopedics,First Hospital of Jilin University were enrolled in this research.The research including 171 knees cases that met the inclusion criteria.The patients who had the preoperative history of patellar developmental deformity and fracture,history of neuromuscular disease,history of metabolic bone disease,history of obvious trauma to the quadriceps extensor device,and history of tumors around the knee joint were excluded.The lateral X-ray view of the patients’ knee before and after the operation were collected and the patients were followed up.The tibial plateau patella angle,Insall-Salvati index and modified Blackburne-Peel index were measured on the lateral X-ray radiographs of the knee before and after surgery by using a measurement software.According to the range defined by the modified Blackburne-Peel index（0.54-1.06）,postoperative patients were divided into patella baja group（29 cases）,patella alta group（10 cases）,and normal patella group（132 cases）.The basic conditions,KSS knee score,KSS functional score,joint range of motion,subjective satisfaction and patellar crepitus were collected and recorded before and after the operation of the patients in each group during follow-up.The statistical analysis was conducted to observe the patella before and after total knee arthroplasty between groups to observe the changes of patella height and the correlation of patella position with knee joint clinical function,joint range of motion,subjective satisfaction and patellar crepitus.Results:There was no significant difference in the KSS clinical total score among the three groups（P=0.151）;there was a significant difference in the KSS functional total score between the patella baja group and the patella alta group（P=0.024）;There was a significant difference in the range of motion between the patella baja group and the normal patella group（P=0.037）;there was a significant difference in subjective satisfaction between the patella baja group and the normal patella group（P=0.034）;there was a statistically significant difference in the patellar crepitus between the patella baja group and the normal patella group（P=0.034）.P<0.001);KSS clinical score（P<0.001）,KSS functional score（P<0.001）and modified Blackburne-Peel index（P=0.001）before and after TKA were statistically significant.Conclusion:In the patients who underwent the total knee arthroplasty without patella replacement,it was found that patella baja had no significant influence on postoperative KSS score,but postoperative patella baja significantly reduced the postoperative range of motion,decreased subjective satisfaction rate and increased the incidence of patella crepitus.