| Total knee arthroplasty(TKA)is currently the main treatment for end-stage knee osteoarthritis,which can relieve pain,correct deformity,and improve function,so the number of TKA procedures is increasing year by year.However,there is still a certain percentage of unsatisfactory rate after TKA,most notably due to complications such as persistent pain,joint dysfunction and reoperation.A good alignment and soft tissue balance is the goal pursued in TKA and a way to improve clinical outcomes and patient satisfaction rates.Among them,the rotational alignment of the femoral prosthesis is crucial,and poor rotation alignment of the femoral prosthesis can easily lead to knee flexion instability,pain in the anterior patellar region,abnormal patellar trajectory,abnormal tibiofemoral joint motion alignment,and ultimately may lead to knee revision.There are two main methods for determining the rotational force line of the femoral prosthesis: measured resection(MR)technique and gap balancing technique(GB)technique,both techniques have their own advantages and disadvantages.There are also many reference markers in MR.Currently 3° external rotation osteotomy of the posterior femoral condyle is used widely,but more and more studies have found that using a uniform 3° of external rotation is not accurate.There is no definitive conclusion as to which method is best.To this end,this study investigated posterior condylar angle(PCA)and the factors affecting it in different populations,starting from anatomical measurements,and also assisted TKA with personalized osteotomy techniques such as preoperative CT measurement of PCA and personalized external rotation osteotomy positioning guide made by 3D printing technology,in order to improve the accuracy of osteotomy of the distal femur and thus obtain a good rotational alignment of the femoral prosthesis.In addition,this study combined the advantages of MR technique and GB technique,and used an innovative pad for measuring the angle of flexion gap and angle rotation device to assist the combination of the two techniques to perform TKA to explore their clinical efficacy and provide reference for clinical application.Part Ⅰ Measurement of femoral posterior condylar angle and analysis of its influencing factors in the population of northern Anhui provinceObjective: To analyze the reliability of measuring the posterior condylar angle(PCA)of femur based on CT three-dimensional reconstruction model,investigate the distribution of PCA in different populations in northern Anhui,and analyze the influencing factors of PCA.Methods: The data of patients who underwent 3D CT of the knee joint and full-length orthogonal X-ray of both lower limbs at Fuyang People’s Hospital,a regional medical center in northern Anhui Province,from January 2018 to July 2021 were selected,and a total of 240 patients were included.Based on the 3D CT image data of the knee joint,a3 D model of the femur was reconstructed using Mimics software,and the PCA was measured.Demographic data such as gender,side,age,and presence of osteoarthritis were recorded,while hip knee ankle(HKA),medial proximal tibial angle(MPTA),and lateral distal femoral angle(LDFA)were measured on full-length films of both lower limbs.The influencing factors of PCA were determined by single-factor correlation analysis and multi-factor linear regression analysis.Analyze the distribution of PCA in different populations based on the influencing factors,and provide a theoretical basis for clinical treatment.Results: The mean PCA of adults in northern Anhui was found to be 3.43±1.18°(0.2-7.2°),with a statistically significant difference compared to the conventionally used 3°(P<0.001);107 of them were male with a PCA of 3.61±1.01° and 133 were female with a PCA of 3.28±1.30° with a statistically significant difference(P=0.031);the PCA was 2.70±0.89° for the group with osteoarthritis and 4.07±0.95° for the group without osteoarthritis,with a statistically significant difference(P<0.05).Correlation analysis showed statistically significant differences in the association between HKA(r=-0.314,P<0.05)and age(r=-0.676,P<0.0001)and PCA;MPTA(r=0.181,P=0.005)and LDFA(r=-0.223,P=0.001)were not statistically significant in association with PCA;Multi-factor linear regression analysis revealed age(b=1.147,t=7.958,P<0.05)and the presence or absence of osteoarthritis(b=0.773,t=5.641,P<0.05)as influencing factors for PCA.The PCA was 2.28±0.84° in patients over 50 years of age with osteoarthritis and 3.48±0.72° in patients under 50 years of age with osteoarthritis(P<0.001).Conclusion: PCA has significant individual differences,and the routinely used 3° of external rotation to determine the femoral prosthesis rotation alignment is not accurate.Age and the presence of osteoarthritis are factors that affect PCA,and preoperative 3D CT examination is recommended for different patients to improve the accuracy of the femoral prosthesis rotation alignment in TKA.Part Ⅱ Application of personalized external rotation osteotomy of distal femur in total knee arthroplasty based on CT measurementObjective: To evaluate the value of personalized distal femoral external rotation osteotomy based on CT measurements in TKA.Methods: From December 2019 to August 2020,101 patients with knee osteoarthritis were admitted to the Department of Orthopedics of Fuyang People’s Hospital,and were randomly divided into an observation group and a control group according to different methods of distal femoral rotation osteotomy,and the observation group performed personalized distal femoral external rotation osteotomy with reference to preoperative CT measurement of posterior condylar angle(PCA)to complete TKA.In the control group,the TKA was performed with a conventional 3° distal femoral external rotation osteotomy,and the medial proximal tibial angle(MPTA),visual analogue scale(VAS)score,knee society score(KSS),and the range of motion(ROM)of knee were measured and recorded before surgery.Intraoperative the state of soft tissue balance in 90° of knee flexion and patellofemoral trajectory were recorded.Postoperatively,the rotational error of the femoral prosthesis and the varus angle of the knee were measured;the VAS score,ROM and KSS score at 3 months and 1-year postoperative follow-up were recorded to evaluate the clinical efficacy.Results:(1)Fifty-one cases,8 males and 43 females,aged 50-84(66.9±7.1)years,in the observation group and 50 cases,8 males and 42 females,aged 56-83(67.8±6.4)years,in the control group,were successfully followed up.The operative time and perioperative amount of bleeding were similar in both groups.(2)In terms of soft tissue balance in the 90° knee flexion position,only 6 cases in the observation group had initial flexion asymmetry(IFA)which was better than 15 cases in the control group(P<0.05).The postoperative knee varus angle was 1°(1°,2°)in both groups,which was significantly improved compared with the preoperative [7°(3°,14°),8°(3°,14°)](P<0.05),and the difference between two groups was not statistically significant(P >0.05).(3)The femoral prosthesis rotation error was smaller in the observation group[0.0°(-1.0°,1.0°)] than in the control group [1.0°(1.0°,2.0°)](P<0.05).There were 5cases(9.8%)of femoral prosthesis rotation error more than 3° after surgery in the observation group and 15 cases(30%)in the control group,and the difference between the two groups was statistically significant(P<0.05).(4)Knee VAS score,ROM,and KSS scores were significantly improved in both groups at 3-month postoperative and1-year postoperative follow-up compared with preoperative scores(P<0.025);the observation group was better than the control group when compared(P<0.05).Conclusion: Personalized distal femoral external rotation osteotomy based on CT measurements for TKA is reliable.The PCA has individualized differences,and personalized external rotation osteotomy of distal femur can obtain a good femoral component rotational alignment,which facilitate flexion gap balance,reduce the incidence of postoperative pain,improve the range of knee motion and clinical efficacy.Part Ⅲ Study on the application of personalized external rotation osteotomy positioning guide in TKAObjective: To explore the accuracy and clinical application effect of 3D printed personalized osteotomy positioning guide.Methods: There are two parts,the first part is an in vitro trial and the second part is a clinical application study.In the first part: in vitro trial,20 patients,including 6 males and 14 females,aged 56-78 years old,average 66.85±6.43 years old,who underwent 3D CT reconstruction of the knee joint in our hospital from January 2022 to February 2023 were searched.The patients’ 3D CT reconstruction data were imported into the computer,and the Mimics software was used to model the knee bones,simulate TKA,and design personalized external rotation osteotomy positioning guides.The most prominent of the lateral epicondyle and the sulcus of the medial epicondyle were identified,and small holes with a diameter of 0.5 mm were designed there,and the line between them was the surgical transepicondylar axis(s TEA).s TEA was used as the target axis to design the personalized external rotation osteotomy guide with reference to the lowest point of the medial and lateral posterior condyles and the horizontal osteotomy surface of the distal femur.Two sets of distal femoral bone models and one set of personalized external rotation osteotomy guide were printed by 3D printer,and two methods were used to simulate TKA for femoral prosthesis installation:personalized osteotomy group: the personalized external rotation osteotomy guide was used to determine the rotation of the femoral prosthesis,and the femoral prosthesis was installed after osteotomy;external rotation 3° osteotomy group: conventional external rotation 3° osteotomy was used to determine the rotation alignment of the femoral prosthesis,and the femoral prosthesis was installed after osteotomy.At the same time,insert two pins in the two small holes of the model,and use the two pins heads as a positioning point to determine the s TEA.After modeling,CT scans were performed to measure and compare the rotation error angle of the femoral prosthesis(the angle between the line of the lowest point of the posterior condyle of the femoral prosthesis and the line connecting the two pins heads)to explore the accuracy of the 3D printed personalized external rotation osteotomy positioning guide.In the second part of the clinical application study,45 patients with knee osteoarthritis were admitted to our hospital from December 2021 to February 2023,and were randomly divided into two groups: 20 patients in the observation group: TKA was performed with a personalized external rotation osteotomy guide,and 25 patients in the control group completed TKA with a conventional external rotation 3° osteotomy.The state of flexion gap of the two groups was recorded,and the knee varus angle and femoral prosthesis rotation error were recorded postoperatively.Results: In the vitro test,the rotational error of the femoral prosthesis was 0.45±0.18° in personalized osteotomy group and 1.92±0.54° in the external rotation 3° osteotomy group in the post-modeling,and the difference between the two groups was statistically significant(P<0.05).In the clinical application part,all patients completed the surgery successfully,and the rotation error of the femoral prosthesis was 0.92±0.77° in the observation group and 1.95±1.04° in the control group,and the difference between the two groups was statistically significant(P<0.05).There was 1 case of femoral prosthesis rotation error more than 3° in the observation group,while there were 6 cases in the control group,and the difference between the two groups was not statistically significant(P>0.05).Ten cases in the control group had initial flexion gap imbalance(IFA)and required soft tissue release,while there were two cases in the observation group,with statistically significant differences between the two groups(P < 0.05).There were no statistically significant differences between the two groups in terms of operative time,perioperative bleeding,and knee varus angle(P>0.05).Conclusion: 3D-printed personalized femoral external rotation osteotomy positioning guide can improve the precision of distal femoral rotation osteotomy,obtain a good femoral component rotational alignment and facilitate flexion gap balance,but the long-term clinical efficacy needs further study.Part Ⅳ Study on the application of the combination of measured resection technique and gap balancing technique in total knee arthroplastyObjective: To explore the value of measured resection(MR)technique combined with gap balancing(GB)technique for total knee arthroplasty(TKA).Methods: Seventy-two cases of knee osteoarthritis admitted to our orthopedic department form January 2019 to December 2021 were randomly divided into a combined resection(CR)group and a measured resection(MR)group,14 male and 22 female in the CR group,age 57-76 years,average 66.22±4.83 years,using the MR technique combined with GB technique.In the MR group,13 males and 23 females,aged 53-79 years,with a mean of 65.89±6.78 years,completed TKA using the MR technique with a conventional 3° external rotation of the distal femur.The operative time,flexion gap balance after osteotomy of femur posterior condyle and perioperative bleeding were recorded intraoperatively,and postoperative knee varus angle,femoral prosthesis rotation error,complications and rehabilitation outcome time were recorded postoperatively,and visual analogue scale(VAS)scare,knee society score(KSS)and the range of motion(ROM)were compared at the last follow-up to evaluate the clinical efficacy.Results: All patients were followed up for at least 12 months.The CR group was better than the MR group in terms of perioperative bleeding,flexion gap balance and prosthesis rotation error(P< 0.05),and the CR group had better VAS,ROM,and KSS scores than the MR group at the final follow-up(P<0.05),with no statistically significant differences between the two groups in terms of operative time,postoperative the varus angle,and complication rate(P>0.05)The CR group recoveried basicly at 5months,while 2 cases in the MR group still had not yet recoveried basicly.There was a significant difference in recovery time cohort information between the two groups,P=0.010.Conclusion: Measured resection technique combined with gap balancing technique to perform TKA for knee osteoarthritis is beneficial to flexion gap balance,reducing trauma,rapid recovery,and improving recent clinical outcomes. |
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