全膝关节置换修复膝内翻畸形：胫股角及膝关节活动度随访评价

doi:10.3969/j.issn.2095-4344.2015.09.001

摘要/Abstract

摘要：

背景：膝关节内翻畸形施行人工全膝关节置换难度大，涉及面多，包括手术入路、术中截骨、软组织松解顺序、方法及程度、软组织平衡等，目前意见不统一，争议较多。
目的：观察全膝关节置换修复成人膝关节内翻畸形胫股角及膝关节活动度的1年以上随访结果。
方法：2006年6月至2013年6月对31例(35膝)膝内翻畸形采用后稳定型假体进行全膝关节置换，髌骨内侧入路，正确截骨，选择性软组织松解，以恢复膝关节正常力线和软组织平衡，获得膝关节的稳定，置换后采取针对性的康复训练。全膝关节置换前后拍X射线片测量胫股角，置换后定期随访检查膝关节活动度，并进行美国特种外科医院(HSS)评分、美国西部Ontario和McMaster大学骨关节炎指数(WOMAC)评估。
结果与结论：所有患者均获得随访，随访时间为12-96个月，随访方式为门诊复查随访。胫股角由置换前平均内翻17.69°(5°-30°)纠正至置换后的5.66°(2°-8°)，膝关节活动度由置换前的74.29°(60°-95°)提高到置换后119.46° (105°-130°)；HSS评分由置换前的26.60分(14-42分)提高到置换后89.03分(82-95分)，优28膝，良7膝；WOMAC评分由42.83分(28-54分)提高到置换后90.17分(85-95分)。结果经统计学分析提示，所有病例置换后胫股角、膝关节活动度、HSS及WOMAC评分均较置换前显著改善(P < 0.01)。置换后X射线片检查未见假体周围透亮区，关节力线正常，无髌骨低位、髌骨骨折。提示成人膝关节内翻畸形患者全膝关节置换后1年以上随访畸形均得到纠正，功能明显改善，修复效果满意。

中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

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关键词: 植入物, 人工假体, 全膝关节置换, 内翻畸形, 后稳定假体, 软组织平衡, 随访

Abstract:

BACKGROUND: Total knee arthroplasty is difficult to perform for treating knee varus deformity, it is highly involved in several issues, such as surgical approach, intraoperative osteotomy, the order, method and extent of soft tissue release, as well as soft tissue balance. There are a lot of controversies for this treatment.
OBJECTIVE: To observe the femorotibial angle and range of knee joint motion of adults patients with knee varus deformity during 1-year follow-up after total knee arthroplasty.
METHODS: A total of 31 patients (35 knees) with knee varus deformity were treated with posterior stabilized prosthesis replacement from June 2006 to June 2013. Using patellar medial approach, the correct osteotomy and selective soft tissue release were performed to restore normal knee alignment and soft tissue balance. Posterior stabilized prosthesis in total knee arthroplasty was applied to achieve knee stability. Postoperative targeted rehabilitation training was also followed. The femorotibial angle was measured before and after surgery. The range of knee joint motion was determined during postoperative follow-up. Patients were evaluated with the Hospital for Special Surgery (HSS) score and the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index.
RESULTS AND CONCLUSION: All patients were followed up for 12-96 months through out-patient clinic. The femorotibial angle was corrected from preoperative varus 17.69° (5°-30°) to postoperative 5.66° (2°-8°); the range of knee joint motion was improved from preoperative 74.29° (60°-95°) to 119.46° (105°-130°); the HSS score increased from preoperative 26.60 points (14-42 points) to postoperative 89.03 points (82-95 points); and the WOMAC score increased from preoperative 42.83 points (28-54 points) to postoperative 90.17 points (85-95 points). Statistical analysis results showed that, total knee arthroplasty significantly improved the femorotibial angle, range of knee joint motion, HSS score and WOMAC score in all involved patients (P < 0.01). Postoperative X-ray films showed no evidence of periprosthetic lucent zone, normal knee alignment, no patella baja and fracture. Total knee arthroplasty surgery can correct knee varus deformity, significantly improve the functions, and achieve satisfactory results at 1 year after surgery.

中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

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Key words: Arthroplasty, Replacement, Knee, Genu Varum, Follow-Up Studies

中图分类号:

R318

李广伟，王红军，孙晓智，陈林斌，高宇亮，白忠旭，程新胜. 全膝关节置换修复膝内翻畸形：胫股角及膝关节活动度随访评价[J]. 中国组织工程研究, 2015, 19(9): 1313-1320.

Li Guang-wei, Wang Hong-jun, Sun Xiao-zhi, Chen Lin-bin, Gao Yu-liang, Bai Zhong-xu, Cheng Xin-sheng. Total knee arthroplasty for knee varus deformity: follow-up evaluation of femorotibial angle and range of motion[J]. Chinese Journal of Tissue Engineering Research, 2015, 19(9): 1313-1320.

图/表（结果） 1

参考文献

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[10] Kim YH, Yoon SH, Kim JS. Early outcome of TKA with a medial pivot fixed-bearing prosthesis is worse than with a PFC mobile-bearing prosthesis. Clin Orthop Relat Res. 2009;467(2):493-503.
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[14] Zhou DG, Lv HS, Du XK. Lower Extremity Alignment Analysis of Varus Knee with X-ray Image. Zhongguo Yixue Yingxiang Jishu. 2001;17(12):1222-1224.
[15] Pan WJ, Jing K, He Y. Early clinical outcome of total knee arthroplasty for patients with knee of varus deformity and flexion contracture. Zhongguo Guyuguanjie Sunshang Zazhi. 2011;26(7):595-597.
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[18] Liu PF, Guo L, Tian FD, et al. Clinical analysis of total knee arthroplasty therapy for unilateral knee varus combined with flexion contracture deformity. Zhongguo Guyuguanjie Sunshang Zazhi. 2013;28(2):119-121.
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[21] Li J, Zheng K, Hu PX, et al. Comparison of short-term result between high-flex and conventional posterior stabilized prosthesis in total knee arthroplasty. Zhongguo Xiufu Chongjian Waike Zazhi. 2010;24(3):278-281.
[22] Kim YH, Sohn KS, Kim JS. Range of motion of standard and high flexion posterior stabilized total knee prosthese. A prospective, randomized study. J Bone Joint Surg (Am). 2005;87(7):1470-1475.
[23] McCalden RW, MacDonald SJ, Bourne RB, et al. A randomized controlled trial comparing “high-flex” vs “standard” posterior cruciate substituting polyethylene tibial inserts in total knee arthroplasty. J Arthroplasty. 2009; 24(6 Suppl):33-38.
[24] Bao YJ, Dong JY, Xu DL. Application of fixed-bearing knee joint prosthesis in treatment of varus deformity in elderly osteoarthritis patients. Jiefangjun Yixueyuan Xuebao. 2013; 34(5):484-491.
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[29] Raviraj A, Prabhu A, Pai S, et al. Fixed vs mobile-bearing total knee arthroplasty: does it make a difference?--a prospective randomized study. J Arthroplasty. 2010;25(5): 835.
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引言

材料方法

Design

A comparative observation trial.

Time and setting

Experiments were performed from June 2006 to June 2013 in the Second Department of Orthopedics, the Second People’s Hospital of Zhengzhou City.

Subjects

31 patients (35 knees) with knee varus deformity were involved in this study, including 5 males (6 knees) and 26 females (29 knees); their age was (57.5±6.5) years and their weight was (28.2±3.2) kg/m². There were 29 knees in 25 cases suffering osteoarthritis, 5 knees in 5 cases suffering rheumatoid arthritis, and 1 knee in 1 case suffering pigmented villonodular synovitis. The course of disease was 3-30 years. The knee axis line was measured by weight-bearing radiography of knee joint. The angular deformity was defined based on the femorotibial angle (FTA), which is the intersection angle of longitudinal axis line of femoral and tibial shafts in the center of knee joint; FTA valgus 5°-10° was a normal range. The preoperative varus deformity was 17.69° (5°-30°) and 11 patients had a flexion contracture of average 23° (5°-45°). Varying degrees of femorotibial medial stenosis was detected in all knee joints, with medial hyperplasia and osteophytes, relocation or subluxation of the patella was also visible. The clinical manifestations included knee pain and dysfunction, which were aggravated when walking. Knee pain was mainly found in the medial joint space of knee joint and the patellofemoral joint, lasting for more than 3 months, and the pain was ineffective by conservative treatment. Preoperative ROM of knee joint was 74.29° (60°-95°). Knee function was determined with the Hospital for Special Surgery (HSS) score and the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Preoperative HSS score was 26.60 points (14-42 points) and WOMAC score was 42.83 points (28-54 points). All patients received primary arthroplasty.

Diagnostic criteria

Patients were included according to the diagnostic criteria of American College of Rheumatology about knee joint degeneration, rheumatoid and other autoimmune diseases, as well as traumatic arthritis secondary to intraarticular fractures^[1-2].

Inclusion criteria: (1) Patients suffer severe pain, deformity and limb dysfunction caused by knee diseases, which seriously affect their quality of life, the pains lasted for more than 3 months and were ineffective by conservative treatment. (2) Patients are strongly positive to receive surgical treatment, they have or have no serious medical illness, which was significantly improved after treatment; patients with stable conditions and tolerate the surgery are suitable for TKA treatment. (3) Primary TKA. (4) All included patients were informed of the trials and signed informed consent.

Exclusion criteria: (1) Early primary osteoarthritis patients, which can tolerate the pains, received non-steroidal analgesics and arthroscopy examination. (2) Congenital developmental defect patients often appear teratogenic deformities in the bone shaft. (3) Patients with knee varus deformity caused by greenstick fracture in the proximal tibia and medial metaphysis during adolescence. (4) Patients with mild physiological knee varus deformity, in good condition and good ROM, having no chronic diseases or rickets. (5) Patients with knee varus deformity caused by traumatic fracture malunion. (6) Patients suffering the pain and dysfunction caused by trauma-induced lateral collateral ligament rupture in knee joint.

Materials

Posterior stabilized cemented knee joint (TC-PLUS, Plus Company, Germany), it is composed of femoral prosthesis, femoral condyles, tibial support, femoral pad and tibial pad, which are all the cobalt-chromium-molybdenum alloys by casting; intramedullary handler and fixation screws are the cobalt-chromium-molybdenum alloys by forging; tibial pad material is ultra-high molecular weight polyethylene. This posterior stabilized cemented knee joint has good biocompatibility by several clinical trials.

Posterior stabilized total knee joint system (Scorpio, Howmedica Company, USA), it is composed of femoral condyle, tibial plateau, distal metals and tibial wedge, which are all the cobalt-chromium-molybdenum alloys by casting; tibia pad and tibial plateau materials are ultra-high molecular weight polyethylene; the developing silk material is the cobalt-chromium-tungsten-nickel alloy; screws are the cobalt-chromium-molybdenum alloys made by forging. Tibial pad material has a ball arcuate surface design, which allows greater rotation range.

Methods

Preoperative preparation

31 patients (35 knee joints) received the surgery by the same surgeon in our hospital. Patients with bilateral knees lesions received one TKA surgery. All patients were treated with posterior stabilized prosthesis, Plus in 26 cases (29 knees) and Stryker in 5 cases (6 knees).

TKA surgery

After femoral nerve was blocked before surgery, patients were fixed in the supine position under epidural anesthesia, pneumatic tourniquet at the pressure of 300 mm Hg (1 mm Hg = 0.133 kPa) was applied to stop bleeding. All knee joints were inserted through the medial parapatellar approach in anterior knee medial incision, the incision was cut along the medial patella to the medial tibial tubercle, exposing the knee joints, then infrapatellar fat pad was completely resected, the suprapatellar bursa and intra-articular synovial membrane were removed. The medial tibia was released and osteophytes were excised to reduce the patellar tendon tension, then the patella was everted. In the valgus process, patellar ligament tension at the tibial insertion point should be controlled, avoiding patellar rupture or avulsion caused by violence. Subsequently, femoral condyle and osteophytes at tibial articular surface were bited, releasing the medial collateral ligament; after anterior and posterior cruciate ligaments were resected, the medial articular capsule and the reflected head of semitendinosus and semimembranosus were released, pes anserinus tendon was cut if necessary and released under the periosteum. Intramedullary positioning was located in the area lateral to the insertion point of anterior cruciate ligament, in femoral intercondylar notch, at the valgus angle of 6°-7° (vertical to the mechanical axis of the femur). According to preoperative X-ray measurements, anterior and posterior femoral condyle, as well as distal femoral bone, were amputated 0.8-1.0 cm, in 3° extorsion. Extramedullary positioning was located in 0°-3° retroversion, followed by the osteotomy. The center axis of the femur and the tibia was taken as a reference of all surgeries, while normal side of joint deformity was used as the reference of positioning the prosthesis, the osteotomy was performed 0.6-1.0 cm below the lowest site of the plateau. After the meniscus, anterior and posterior cruciate ligaments were cut, the femur and the tibia were subjected to the osteotomy, which was performed in strict accordance with the mold guidance. Knee joints were straightened and the prosthesis model was inserted, the prosthesis activity and the collateral ligament balance were detected under the extension and flexion conditions. After replacement, the prosthesis activity should allow a 3°-5° hyperextension. The TKA surgery was not performed in patellar bone. The patellar osteophytes were bited and the patellar articular surface was trimmed, eliminating the spalling and exfoliative cartilage, so the patellar size was reduced and close to normal articular surface, good patellofemoral track can be obtained after denervation. Tourniquet was released and wounds were repeatedly rinsed, articular capsule was sutured in the flexion position and soft tissue was also sutured (Figure 1).

Postoperative treatment

The lower extremities were moderately wrapped using elastic bandage, drainage tube was clamped for 2 hours, the affected limbs were compressed on ice to reduce bleeding effusion and soft tissue swelling. Aspirin or low molecular weight heparin was given postoperatively to prevent deep vein thrombosis. At postoperative day 1, with the assistance of femoral nerve pump and analgesic drugs, patients performed active knee extension and flexion exercise, mainly in the quadriceps, triceps surae and ankle joint. At postoperative day 2, drainage tube was removed, patients received compression exercise in quadriceps and knee joints. At postoperative day 3, patients continued to strengthen knee extension and flexion exercise in bed, while sitting on the bed and walking under the assistance of walking aids. At postoperative day 7, knee joints can reach 0° extension and 90° flexion, lower extremity muscle strength was significantly enhanced, and patients could walk with the aids. Chinese medicine fumigation and massage were suggested to perform if the clinical outcome was unsatisfactory. In addition, continuous passive motion auxiliary exercise or rehabilitation exercises were also feasible.

Evaluation criteria

HSS score was applied to detect the knee joint function before and after TKA surgery. The total score was 100 points, including 30 points for pain, 22 points for functions (walking, climbing stairs, and use of vehicle), 18 points for ROM, 10 points for muscle strength, 10 points for flexion deformity, and 10 points for stability. The scores are reduced if patients use crutches and walking aids, or the joint extension is limited. Excellent: 85-100 points; good: 70-84 points; fair: 60-69 points; poor: < 60 points.

WOMAC score was the indicator of knee joint structure and function through the pain, stiffness, and joint function. There are 24 projects in WOMAC, which cover all signs and symptoms of osteoarthritis. Five items are about the pains, two items about the stiffness, and 17 items about joint function. Standardized scores are obtained through the total scores divided by the number of items.

Main outcome measures

All involved patients were followed up for 12-96 months through the out-patient clinic visits. Before surgery and at 3, 12, 24 months after surgery, patients were detected as follows: FTA was measured by anterioposterior and lateral radiography, and axial radiography of patellofemoral joint. The joint alignment and patellar height were assessed. The knee ROM and pains were examined during follow-ups. Subsequently the follow-up was performed every 12 months, HSS and WOMAC scores were also measured. The HSS scores at the final follow-up (ended by June 2014) were the latest data collected within the recent 6 months, patients who were lost in the long-term follow-ups were excluded. Data at the final follow-up were analyzed.

Statistical analysis

Statistical analysis was performed using SPSS 19.0 software. Data were expressed as the mean±SD. The difference before and after TKA surgery was compared using the t-test. A P < 0.05 was considered statistically significant.

中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

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讨论

Severe knee deformity is divided into varus deformity, flexion deformity and valgus deformity^[3], patients often suffer joint pain and dysfunction, severe cases require long-term bed, which affect their quality of life^[4]. With the improvement of knee prosthesis and installation techniques, TKA has been relatively mature. However, improper operations and perioperative mistreatment may induce serious complications, affect clinical efficacy and result in surgical failure. A large-scale epidemiological study has demonstrated that, approximately 20% of patients were uncertainty and even dissatisfied with the surgical treatment^[5]. As knee joint replacement involves many aspects, the selections of surgical indications, surgical approach, osteotomy method, soft tissue balance and prosthesis type remain controversial. This study analyzes knee varus deformity patients as follows.

Cause of knee varus deformity

Knee varus deformity is mainly induced by tibial deformity, especially in cases with medial compartment damage, the medial tibial plateau appears bone defects, which are often accompanied by tibial semiluxation; femoral and tibial osteophytes may cause soft tissue tension; medial structures of knee joints include the medial collateral ligament, semimembranosus tendon of posterior medial angle structure, posterior articular capsule and pes anserinus contracture^[6-7]. Knee varus deformity at advanced stage can lead to the loosening of lateral structure^[8]. In patients with severe knee varus deformity, lateral ligament soft tissue becomes thinning and loosening, the medial soft tissue loosening cannot contribute to maintain the knee joint balance under the flexion and extension positions, although mild valgus deformity is acceptable in severe varus deformity patients, obvious loosening can trigger knee joint semiluxation^[9]. Some Chinese scholars have proposed that, long-term abnormalities of knee joint alignment may cause the wear of medial tibial plateau, the contracture of medial collateral ligament, and the loosening of lateral collateral ligament. FTA only reflects the overall situation of varus, but it cannot clearly demonstrate the angles of varus deformity, especially in elderly patients with degenerative joints, soft tissue imbalance and the wear of articular surface are very common.

Release of soft tissue

It is the major treatment of knee varus deformity, with the aim to alleviate knee pains, correct varus deformity, stabilize knee joints, and restore normal knee functions^[10]. At the same time, soft tissue balance is the premise of good prosthesis position and alignment^[11]. In the TKA surgery, the surgical correction degree is determined based on the varus deformity severity of soft tissue around the knee joints under the tension condition^[12]. Therefore soft tissue balance is very important for the success of TKA surgery. Soft tissue imbalance can cause stress concentration between metal prosthesis and polyethylene, accelerate wear damage and result in prosthesis failure, it also causes knee instability and prosthetic loosening or abnormal sound. Therefore, it is important to maintain soft tissue balance during and after replacement surgery. There are controversies in the order, method and extent of soft tissue release. Karachalios et al^[13] found that the surgical correction included not only osteotomy, but also medial ligament release and soft tissue release. The measurement results showed that, the varus angle in varus osteoarthritis patients was not solely determined by tibial mechanical varus, it is the results caused by the wear of medial femur and tibial articular surface, the medial tibial plateau collapse, and ligament imbalance. Only tibial mechanical varus accounted for 22.8% of knee varus. Postoperative X-ray findings showed that, the osteotomy at the tibial plateau only corrected 27.9% of knee varus deformities. While 72.1% of varus angle was corrected by the medial collateral ligament release and soft tissue balance^[14]. Our research group proposes that, for patients of severe knee varus deformity and flexion deformity, careful observations of preoperative radiographic films, precision design, clear position and height of osteotomy, as well as surgical methods should be paid more attention. Knee varus and valgus deformities can be corrected by the removal of distal femoral and the medial proximal tibial osteophytes, as well as primary osteotomy. If joint space balance is achieved, soft tissue release is not necessary, only the removal of osteophytes can release the medial collateral ligament and achieve soft tissue balance, also prevent postoperative medial tibial bursitis. If joint space imbalance is still present, soft tissue release is suggested and the release order is regulated according to the functions of medial stable structure under the flexion and extension positions, thus achieving good balance of soft tissue under different conditions. Knee varus patients are often accompanied by flexion contracture deformity^[15]. Flexion deformity can be treated by the release of medial joint capsule and semimembranosus, to correct flexion varus and knee rotation deformity. When knee flexion contracture was higher than 15°-20°, posterior cruciate ligament is a part of this deformity, so posterior cruciate ligament should be removed to achieve full extension of knee joints^[16-18]. Based on the above treatment and the osteotomy, knee varus deformity can be basically corrected and knee joint can freely extend and flex^[19]. According to the principle of releasing and measuring simultaneously, physicians should moderately release and carefully observe, avoid over-correction and knee instability. Medial and lateral collateral ligaments are the basic stable structure of the knee joint, the stability is so important that we cannot select release without consideration. In addition, bone cement, bone graft and stepped prosthesis are suggested for the medial tibial plateau wear, collapse and bone loss, and have achieved good results.

Choice of prosthesis

The well-matched prosthesis can fundamentally improve the excellent and good rates of TKS surgery, large-scale anatomical data are crucial for the improvement of prosthetic design and operation technology. Therefore the difference of knee joint between Chinese people and foreigners, between Chinese men and Chinese women, should be carefully considered, the difference includes the size difference and the morphological difference. High quality of prosthesis and localization of accurate surgical instruments will promote the popularization and development of knee joint replacement in China^[20]. Chinese people prefer to squatting, so a high-flexibility prosthesis occurs. Theoretically, the prosthesis can not only increase the ROM, but also reduce the incidence of anterior knee pain and the wear of polyethylene pad, but it has no superiority in the maximum flexibility and ROM of knee joint than posterior stabilized prosthesis^[21]. This result is consistent with the findings of Kim et al ^[22]. Therefore a high-flexibility prosthesis has some uncertainties in improving the joint flexion after surgery^[23], produces continued adverse stress and gradually leads to soft tissue loss imbalance, and seriously affects postoperative stability of knee joint^[24]. Some scholars proposed that high-flexibility prosthesis is only suitable for patients with good preoperative ROM^[25]. Whether the patella receive TKA surgery remains controversial, and the incidence of anterior knee pain after TKA surgery is quite different^[26-27]. Zou et al found no difference in the incidence of anterior knee pain between patellar replacement group and non-replacement group^[28]. But there was no significant difference between the high-flexibility prosthesis and normal prosthesis in anterior knee pain and function^[29]. In this study, patients were treated with posterior stabilized prosthesis, requiring accurate alignment of the femur and tibia, and ensuring that the femoral head center, the knee joint center and the ankle joint center are placed in a straight line after prosthesis implantation. Tibial osteotomy was performed in 0°-3° retroversion angle, the extorsion position of femoral prosthesis and the retroversion position of tibial prosthesis were determined, patellar articular surface was trimmed and denervated, and the soft tissue at lateral patellar was released. These contributed to obtain a good patellofemoral track and reduce postoperative complications such as patellar pain, patellar dislocation and poor knee flexion. In addition, soft tissue release achieved 0°-5° hyperextension in knee joints, although the loss of angle is present, the results were still satisfactory.

In summary, as the aging process, the incidence of bone and joint diseases is increasing and more patients suffer secondary joint deformity. Knee replacement surgery can obtain a painless, stable, deformity-correction, and well-functional joint, thereby improving patient’s quality of life. However, knee replacement surgical procedure is very complex and involves many factors. The therapeutic effect is ineffective in some patients, a systemic evaluation of both the surgery and the patient’s condition is suggested to clearly determine the failure cause; in addition, detailed history, physical examination, laboratory testing and radiographic findings are applied to exclude related diseases and develop appropriate treatment according to the disease condition. Firstly, the location and angle of the osteotomy should be determined, patients are classified according to knee varus severity, in accordance with the patient's condition, a reasonable osteotomy and selective soft tissue release can achieve soft tissue balance. It is important in TKA surgery to select appropriate prosthesis, ensure accurate alignment of the femur and tibia, focus the position of prosthesis, correctly treat the patella, and perform postoperative rehabilitation exercises. These measures can reduce postoperative patellar pain^[30], patellar dislocation and poor knee flexion, and maximize functional rehabilitation, achieve good short-term and long-term results of knee replacement surgery.

中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程
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