Comparison Of The Radiographic Changes Of Patellar Position After Total Knee Arthroplasty With And Without Computer-aided Navigation

Objective To compare the radiographic changes of patellar position after total knee arthroplasty with computer-aided navigation and that with conventional surgery and to explore if the technology of computer-navigation can improve the patellar position.Methods From January2008, we performed a prospective randomized study for operation between computer-aided navigation and conventional surgery in TKA in Yantaishan Hospital. According to inclusion and exclusion criteria, Eighty-five patients (95knees) meet criteria, Forty-one patients underwent computer-aided navigation. Forty-four patients (48knees) underwent conventional surgery. All operations were performed by a same senior surgeon.1. Clinical Evaluated System:KSS Score for knees; Feller Score for patella; anterior knee pain (AKP).2. Radiographic Evaluation standard:the mechanical axis of lower extremity, the patellar tilt angle (PTA), the lateral patellar displacement (LPD), the Insall-Salvati ratio, the mechanical axis. All data was analyzed using SPSS13.0software, significant difference used P<0.05.Results1、Clinical Evaluated System:①Comparing the group of computer-aided navigation with the conventional surgery, the postoperative mean KSS score was no significant difference (P>0.05). But postoperative mean KSS score was significant higher than preoperative in two groups (P<0.05). The preoperative mean Feller patellar score was significant higher than preoperative in two groups (P<0.05).②Comparing the preoperative incidence of AKP and the max flexion with the preoperative, the difference was statistically significant (P<0.05) in two groups.2、Radiographic Evaluation:①There were statistically significant differences between two groups of the patellar tracked centrally (P<0.05) at the preoperative3、6and12months.②The postoperative Insall-Salvati ratio of two groups were no significant difference (P>0.05). At the preoperative12months, compared the mechanical axis of lower extremity with deviation≤±3°in two groups, the difference was statistically significant (P<0.05). A lateral release was performed; there were one in computer-aided navigation group and five in conventional surgery group. Postoperative complication:One patients suffered from complication with infection. Thirty patients were the deep vein thrombus (DVT). One patient suffered from complication with fat liquescence. There was fracture in one patient. One dislocation knee occurred in conventional surgery group after external injury.Conclusionsl.At the end of twelve months follow-up, regardless of computer-aided navigation or conventional surgery in TKA, the patients with osteoarthritis would gained the improvement of pain and function, thereby improved patient’s life quality and recovered daily groundwork and activity; patients with computer-aided navigation or conventional surgery in TKA didn’t found severe complication. Compared with conventional surgery, computer-aided navigation can reduce the incidence of AKP.2. The radiographic changes of patellar position after total knee arthroplasty was better in computer-aided navigation group than in conventional surgery group. Utilizing computer assisted imaging guidance in TKA can obtain the better patellar tracking.3.More researches are needed to investigate the influence of computer-navigation assisted TKA on the radiographic changes of patellar position and patellar tracking.