Unicompartmental Knee Arthroplasty Patellar Tendon Length Changes

Objective:To investigate the change in the length of patellar tendon after Unicompartmental knee arthroplasty, compare with Total knee arthroplastyand to embody its superiority.Methods:The unicompartmental knee arthroplasty were performed on sixty-one knees of fifty patients from January 2005 to January 2008 by one surgeon at Department of Orthopaedics,Taiyuan Huajin Hospital and Department of Orthopaedics, the Second Hospital of Shanxi Medical University.The osteoarthritis was diagnosed in all knees. Thirteen patients were unavailable for review because of death or lossto follow-up.Clinical details were available for the remaining forty-one knees since bone-sign of three knees were not obviously. Time of follow-up is from eight months to forty-four months after operation. Standard lateral radiographs of the knees were taken by computer radiographs system, the length of patellar tendon was measured before and eight months after operation by AUTOCAD software, method of measurement is to measure the distance from a point on the inferior pole of the patella and the tibial tuberosity. The range of flexion was measured by a goniometer. WOMAC (Western Ontarion and MacMamster) Score were recorded before and eight months after the operation. The statistical analysis was made by paired t-test. One sample t-test of the range of flexion was made by reference documents of TKA.Results:forty-one patients were followed up for 8-44months. No complication, infection, loosening occurred. The WOMAC score before operation is 32.6,after operation is 5.2. there was statistical significant between before and after the operation (P<0.01). It means therapeutic effect after operation is very great. The mean length of patellar tendon before operation is 41.3mm,after operation is 41.08mm. after operation,the patellar tendon had shortened by a mean of 0.46%(-13%-10%shorter). there was no statistical significant between the length of patellar tendon before and after operation(P＞0.01), the length after TKA had no significant change,but TKA had. there was statistical significant between range of flexion before and after the operation (P<0.01).The range of flexion after UKA operation is greater than UKA, P<0.01.Conclusion:Eight to forty-four months therapeutic effect after UKA is excellent, the length of patellar tendon after UKA had no significant change, it has injury and interference with biomechanics of knee and extensor apparatus more lightly. Compared with Total knee arthroplastyand,it can recover the motion characteristics of knee more excellent. As far as it is concerned,It is worth of spreading.