Influence of retention or resection subpatellar fat pad on patella height during rheumatoid knee replacement

Abstract

To compare influence of retention or resection subpatellar fat pad on patella height during rheumatoid knee replacement. Totally 48 patients with rheumatoid arthritis who underwent total knee replacement from October 2013 to October 2017 were retrospectively analyzed and divided into resection and retention subpatellar fat pad group. There were 23 patients in resection subpatellar fat pad group, including 9 males and 14 females aged from 48 to 69 years old with an average of(55.83±5.65) years old; subpatellar fat pad were resected during opertaion. There were 25 patients in retention subpatellar fat pad group, including 6 males and 19 femlaes aged from 49 to 70 years old with an average age of (55.52± 6.28) years old;subpatellar fat pad were retentedduring opertaion. Postopertaive complications were observed between two groups, visual analogue scale (VAS) and Hospital for Special Surgery (HSS) at 1 year after operation were used to evaluate relieve pain degree and clnical effect of knee joint, Insall-Salvati ratio(I-S ratio) was used to compare changes of postoperative patella height at 1 year after operation. All patients were followed up from 12 to 39 months with an average of (23.85± 8.82) months. The postoperative wound healed well without infection complications and no prosthetic loosening or revision. Postoperative VAS score at 1 year between two groups was lower than that of before opertaion(P<0.05), but no statistical difference between two groups at 1 year after operation(P>0.05). Postopertaive HSS score between two groups was higer than that of before operation(P<0.05), while no difference in HSS score at 1 year after operation between two groups (P>0.05). I-S ratio of subpatellar fat pad resection group (1.03±0.04) was lower than that of subpatellar fat pad retention group (1.06±0.06), and difference was statistically significant (P<0.05). Resection or retention subpatellar fat pad in rheumatoid knee replacement have advantages of relieving postoperative pain and improving functional recovery, however, retention of infrapatellar fat pad is beneficial to restoration of patellar height.