2025年 · 第105卷第15期

A 59-year-old female went to the Sports Medicine Department of the Second Affiliated Hospital of Xi' an Jiaotong University because of "prolapse of the lateral left patella for more than 50 years and aggravation of pain for 1 week". More than 50 years ago, the patient had left patella prolapsed laterally due to trauma, accompanied by severe pain in the affected knee and limited flexion and extension movements. After conservative treatment, the symptoms were relieved without attention, and the pain repeated, and the left patella continued to dislocate. 1 week ago, pain was aggravated after exercise, accompanied by walking disorders, and was unable to walk independently, which was not relieved by oral non-steroidal anti-inflammatory drugs. Physical examination showed: left femoral internal rotation deformity, left knee patella extremely external movement, unable to be manually reduced; Circumpatellar tenderness positive; Knee flexion and extension 0-20°; Severe atrophy of medial femoral muscle, quadriceps muscle strength grade 3; The patellar grinding test was positive and the patellar extrapolation test was positive (more than 4/4) (Panel A). X-ray examination of the left knee showed that the patella was invisible on the lateral radiograph, and the lateral dislocation of the patella on the axial radiograph; CT examination of the left knee showed degenerative lesions of the knee joint with osteophyte formation and lateral dislocation of the patella (Figures B and C). Fixed patellar dislocation, osteoarthritis of the knee was diagnosed. Total knee arthroplasty combined with quadriceps myoplasty for repair of patellar dislocation was performed after admission. Postoperative functional exercise was performed by wearing chuck braces. After half-year reexamination, the patient self-complained that he had recovered well, the muscle strength of his left lower limb improved compared with before, the walking function had recovered, and he was able to complete most daily activities. Fixed patellar dislocation is a rare lesion of the knee joint in which the patella is detached from its normal anatomical position for a long time and is fixed in an abnormal position that cannot be reduced by active or passive means. Such dislocations usually develop gradually during developmental stages or due to specific etiologies, rather than due to acute trauma. It is often accompanied by deformities such as femoral internal rotation, tibial external rotation or knee varus/valgus, and is more common in patients with developmental abnormalities or congenital diseases (such as joint laxity and congenital deformities). Due to the long duration of the disease, patients usually have severe decrease in lower extremity muscle strength.