Relationship between changes in joint line position of knee and clinical function after TKA

JI Song-jie; TIAN Wei; JIANG Xu; ZHOU Yi-xin

doi:10.3969/j.issn.1002-266X.2015.12.03

Abstract：Objective To observe the changes of the knee joint line position after total knee arthroplasty ( TKA) , and to investigate the relationship with the clinical features .Methods Eighty-nine patients who received TKA were selected randomly .Posterior stabilized prosthesis ( GENESISⅡ) was used in all patients .According to the method recommended by Hofmann, the distance between adductor tubercle of femur and distal line of femoral condylar which represented the joint line position was recorded .Pre-and post-operative knee joint line was measured , and the changes of pre-and post-operative knee joint line were calculated .The KSS and Feller scores were used to assess pre-and post-operative knee and knee exten-sion apparatus function .The correlations between the changes of joint line and Feller scores were analyzed .Results The implant survival rate was 100%(89/89) during the postoperative follow-up.The anteroposterior and lateral X-ray of knee did not show radiographic loosening , and the knee KSS , function, mobility and Feller patellar scores increased as compared with that preoperative (all P<0.01).The knee KSS, function, mobility and Feller patellar scores were higher in the pa-tients whose JL level changes ≤4 mm than those whose JL>4 mm (P<0.05 or P<0.01).The Feller patellar scores in patients whose JL changes ≤4 mm was not related with the altitude of changed JL (r=-0.162, P=0.205); while the Feller patellar scores in patients whose JL changes >4 mm was negatively correlated with the altitude of changed JL ( r=-0.724, P=0.000).Conclusions The joint line changed within 4 mm in patients who underwent TKA for the first time by using posterior stabilized prosthesis may result in a better knee joint function after TKA .The joint line change is nega-tively correlated with knee extension apparatus function .