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Objective:To investigate the feasibility and therapeutic effect of total knee arthroplasty (TKA) with cruciate-retaining (CR) prosthesis by using FEM-X1 femoral extramedullary positioning instrument based on the theory of restricted kinematic alignment (rKA).Methods:Thirty five cases who underwent total knee arthroplasty in Nanjing Drum Tower Hospital from November 2019 to December 2020 were retrospectively analyzed, including 7 males and 28 females with an average age of 71± 8 years (ranging from 55 to 85 years) Following the guidance of rKA alignment, the FEM-X1 femoral extramedullary positioning instrument was used for TKA with CR prosthesis. Before the operation, the full-length lower limb radiographs of both anteroposterior and lateral views were taken in a standing position for preoperative assessment of lateral distal femoral angle (LDFA), the medial proximal tibial angle (MPTA) and hip-knee-ankle angle (HKA). According to the principle of rKA alignment, the target LDFA, MPTA and HKA were calculated. The proximal end of tibia and distal end of femur were cut using extramedullary positioning instrument respectively. The posterior femoral condyle was cut according to the tibial plateau and mediolateral soft tissue tension. The prosthesis was installed after osteotomy. The release of collateral ligaments, PCL function, release of PCL, patellofemoral trajectory, release of patellofemoral support band, the amount of blood loss and time of operation were recorded. Postoperative LDFA, MPTA, HKA, and posterior slope angle of tibial prosthesis were measured on X-ray images. The Knee Society Score (KSS) was used for functional evaluation.Results:Thirty five cases of TKA with CR prosthesis following rKA alignment were successfully completed. The operation time was 100 (90, 110) min, and the blood loss was 100 (100, 200) ml. 30 of them were followed up for 12.5±0.7 months (ranging from 12 to 14 months). The pre-operative and post-operative LDFA were 1.0°(-2.0°, 4.0°), 0°(-2.0°, 2.0°), MPTA were -4.0°(-5.0°, -1.0°), -2.0°(-3.0°, -1.0°), HKA were -3.0°(-3.0°, -1.0°), -2.0°(-3.0°, -1.0°). There was no significant difference between the three angles before and after operation ( Z=-0.89, P=0.372; Z=1.87, P=0.061; Z=1.03, P=0.302). The average posterior tibial slope was 5°(3°, 7°). At the follow-up of one year, the KSS clinical score was 94(92, 97) and functional score was 80(70, 90) in 30 cases. During the operation, PCL was released in 1 case because of excessive tension; and lateral retinacular release was performed in 1 case because of poor patellofemoral track. Conclusion:ITKA with CR prosthesis by using the extramedullary positioning instrument on the theory of rKA alignment showed a good clinical outcome at a short follow up.
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ObjectiveTo explore the effect of kinematic alignment on postoperative knee function for patients after total knee arthroplasty (TKA). MethodsFrom June, 2020 to October, 2021, 200 patients undergoing primary TKA in Beijing Chaoyang Hospital were divided into mechanical alignment (MA) group (n = 100) and kinematic alignment (KA) group (n = 100). All the patients accepted comprehensive rehabilitation after operation. They were assessed with Keen Society Score (KSS) before and three months after operation, with Visual Analogue Scale for pain (VAS) before, and three days and three months after operation. The time of first standing, the time of first straight-leg raising more than 30°, and the active range of motion (AROM) of knee before, and one, two and three days, and one and three months after operation were recorded, as well as where to go after discharge. ResultsA total of 96 patients in MA group and 98 in KA group finished the research. The AROM of knee improved more in the KA group than in the MA group after operation (Fgroup = 8.816, P = 0.017), and the incidence going to the rehabilitation institutes was less (χ2 = 6.542, P = 0.011). ConclusionKA may promote the rapid recovery of AROM of knee for patients after TKA, and reduce the needs of institute-based rehabilitation after discharge, to save medical costs.
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BACKGROUND: Although mechanical alignment technique ensures the long-term survival rate of knee arthrosis, some patients are still not satisfied with the effect of total knee arthroplasty and the function of knee joint after operation. OBJECTIVE: Meta-analysis was used to evaluate the effect of kinematic alignment technique and mechanical alignment technique in the guidance of total knee arthroplasty. METHODS: The literature of clinical controlled study of kinematic alignment and mechanical alignment in the guidance of total knee arthroplasty published from the date of establishment to July 2019 was searched in Chinese Biomedical Literature Database, Wanfang data, CNKI, VIP data, PubMed, Cochrane Library, and Embase. The literature was screened, and evaluated; data were extracted. Review Manager 5.3 software was used for statistical analysis. RESULTS AND CONCLUSION: (1) A total of 945 cases were included in 12 articles, including 470 cases in kinematic alignment group and 475 cases in mechanical alignment group. (2) The results of meta-analysis showed that the operation time was shorter in the kinematic alignment group than in the mechanical alignment group [MD=-15.44, 95%C/(-27.16, -3.71)]. Western Ontario and McMaster University Osteoarthritis Index was better in the kinematic alignment group than in the mechanical alignment group [MD=-8.40, 95%C/(-15.39, -1.40)]. Oxford knee score was better in the kinematic alignment group than in the mechanical alignment group [M7=4.72, 95%C/(0.24, 9.21)]. Distal angle of mechanical lateral femur and proximal angle of mechanical medial tibia were significantly larger in the mechanical alignment group than in the kinematic alignment group (all P 0.05). (4) The function of knee joint after kinematic alignment for guiding total knee arthroplasty was better than that in mechanical alignment group. However, the imaging and perioperative results were similar, and the incidence of complications was not increased after operation. It is suggested that kinematic alignment may be a lower extremity force alignment method to guide total knee arthroplasty.
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Kinematically aligned total knee arthroplasty (TKA) is a new alignment technique. Kinematic alignment corrects arthritic deformity to the patient's constitutional alignment in order to position the femoral and tibial components, as well as to restore the knee's natural tibial-femoral articular surface, alignment, and natural laxity. Kinematic knee motion moves around a single flexion-extension axis of the distal femur, passing through the center of cylindrically shaped posterior femoral condyles. Since it can be difficult to locate cylindrical axis with conventional instrument, patient-specific instrument (PSI) is used to align the kinematic axes. PSI was recently introduced as a new technology with the goal of improving the accuracy of operative technique, avoiding practical issues related to the complexity of navigation and robotic system, such as the costs and higher number of personnel required. There are several limitations to implement the kinematically aligned TKA with the implant for mechanical alignment. Therefore, it is important to design an implant with the optimal shape for restoring natural knee kinematics that might improve patient-reported satisfaction and function.
Subject(s)
Arthroplasty, Replacement, Knee , Biomechanical Phenomena , Congenital Abnormalities , Femur , KneeABSTRACT
Many factors contribute to a successful total knee arthroplasty, and postoperative coronal lower limb alignment has always been a focus of joint surgeons. Previous researches have suggested that neutral alignment can bring higher prosthesis survival rate and better knee function. However, the theory has been challenged in recent years.In this article, the author introduces the axis, alignment and osteotomy of total knee arthroplasty briefly and reviews the studies on the neutral alignment and kinematic alignment of recent years in order to provide some advice for the clinical operation.