Change of related functions and double lower limb length after total knee arthroplasty / 中国组织工程研究

ABSTRACT

BACKGROUND: There are many reasons for poor function after knee arthroplasty. Leg length discrepancy is one of them. The extent of influence on the function of knee joint after arthroplasty has not been fully studied. OBJECTIVE: To analyze the change degree, possible influencing factors and functional changes of leg length discrepancy in patients after total knee arthroplasty. METHODS: Totally 107 patients (124 knees), including 23 males and 84 females, were included from October 2016 to September 2018, who entered the Department of Orthopedics of Affiliated Hospital of Xuzhou Medical University for total knee arthroplasty. There were 90 cases of unilateral total knee arthroplasty (90 knees) and 17 cases of bilateral total knee arthroplasty (34 knees). Three cases (6 knees) of bilateral total knee arthroplasty received separate treatment with an interval of more than 6 months, and entered the unilateral knee group. Therefore, there were 93 cases (96 knees) in the unilateral knee group, and 14 cases (28 knees) in the bilateral knee group. Patients signed the informed consent. This study was approved by the Hospital Ethics Committee. At preoperative and postoperative 10 days and 6 months, full length anteroposterior radiographs were taken, and the length of the lower limb and hip-knee-ankle angle were measured and recorded. Angle of knee flexion contracture was measured and the hospital for special surgery knee score was recorded. RESULTS AND CONCLUSION: (1) The length of patients' lower limbs was increased by the correction of deformities after total knee arthroplasty. The length of lower limbs 10 days after surgery was longer than that at 6 months after surgery. The lower limbs of 70.2% of the patients were increased 10 days after total knee arthroplasty, and 79.0% of the patients were increased 6 months after total knee arthroplasty. At 10 days and 6 months postoperatively, the postoperative corrected flexion contracture angles were positively correlated with the change of postoperative lower limb length. (3) Limb lengthening on the operative side was positively correlated with increased hospital for special surgery knee score after surgery. (4) The incidence of leg length discrepancy before and after surgery was almost equal 45.1 % preoperatively, 55.3% 10 days postoperatively, and 46.0% 6 months postoperatively. (5) The leg length discrepancy preoperatively and 6 months postoperatively was influenced by the difference of deformities between the pair of limbs. Preoperative influencing factors were the difference of hip-knee-ankle angle and flexion contracture of both lower limbs. The difference value of flexion contracture of both lower limbs was the factor affecting the leg length discrepancy 6 months after surgery. Leg length discrepancy before surgery and 6 months after surgery was affecting the difference of hospital for special surgery knee score between lower limbs.