Radiographic Assessment Of Aseptic Loosening Of Tumor-type Knee Prosthesis In Distal Femur And Clinical Research On The Relationship Between Postoperative Knee Joint Function And TCM Constitution

Objective: This study aimed to measure the radiographs of lower limbs after the resection of a tumor in the distal femur and tumor-type knee prosthesis replacement and to analyze the factors that led to aseptic loosening of the prosthesis from two aspects of prosthesis parameters and lower limb alignment.And to explore the influence of different types of TCM constitution on postoperative knee function.Methods: A total of 26 cases of tumor-type knee prosthesis replacement or revision due to the distal femoral tumor at our hospital from January2007 to December 2019 were retrospectively analyzed.The patients were divided into the loosening and unloosening groups depending on whether aseptic loosening occurred after surgery or not.The clinical data were analyzed.Full-length anteroposterior and lateral radiographs of lower limbs were used.Bone resection length,length of prosthetic parts,handle of the medullary cavity vertex distance before the femoral maximize arch radian distance,diameter of the medullary stem,hip–knee–ankle angle(HKAA),mechanical lateral distal femoral angle(m LDFA),mechanical medial proximal tibial angle(m MPTA),and lower limb alignment from the center of the knee joint were measured.Data were analyzed,and the risk factors for aseptic loosening of the prosthesis were explored.A total of 54 cases of tumor-type knee prosthesis replacement due to the distal femoral tumor at our hospital from January 2010 to September 2021 were retrospectively analyzed.The TCM constitution classification of the patients was carried out by questionnaire.Meanwhile,the knee function of the patients was recorded,including knee range of motion,MSTS score,TESS score,KSS score for statistical processing.Results:1.The ratio of prosthesis length to femur length(63.72±5.21)and the ratio of pulp stem diameter to femur diameter(26.03±8.45)in the loosening group were smaller than those in the unloosening group.The difference was statistically significant(P < 0.05).On the contrary,the distance between the apex of the medullary stem and the maximum arc of the anterior femoral arch(3.47±2.96)in the loosening group was significantly shorter than that in the unloosening group and the difference was statistically significant(P < 0.05).The measurement of the lower limb alignment showed significant differences between the loosening and unloosening groups in terms of HKAA,m LDFA,and distance between the lower limb alignment and the center of the knee joint(P < 0.05).2.The logistic regression analysis showed that less than 30% ratio between the diameter of the medullary stem and the diameter of the femur,less than 3 cm distance between the apex of the medullary stem and the maximum curvature of the anterior arch of the femur and presence of varus knee and valgus knee after surgery were the risk factors for aseptic loosening of the prosthesis.3.There was no statistical difference in TCM constitution distribution of patients after knee prosthesis replacement for distal femur tumor,but the balanced constitution accounted for the highest proportion(24.1%).4.TCM constitutions of different types have an impact on knee joint function,patients with Qi deficiency and Yin deficiency have poor postoperative knee joint function,and there is a statistical difference in MSTS between Qi deficiency(17.73±4.41)and balanced constitution(24.08±2.53).Yin deficiency(76.89±11.47°)and balanced constitution(102.69±15.80°)had significant difference in knee motion.Conclusion:1.The use of a medullary stem with a longer length and a thicker diameter in the tumor-type knee prosthesis replacement surgery was recommended.The standard lower limb alignment was also beneficial in reducing the prosthesis loosening rate.2.After knee prosthesis replacement for tumor type of distal femur,the TCM constitution of the patients was still mainly peaceful,and the deficiency syndrome was mainly in the biased constitution,among which Qi deficiency,Yang deficiency and Yin deficiency accounted for the highest proportion.Different types of TCM constitutions affect the postoperative function of knee joint,and patients with Qi deficiency and Yin deficiency have poor postoperative function of knee joint.Therefore,TCM constitutions should be timely classified for patients after surgery to intervene in abnormal TCM-based constitution.