With the aging of our population, the number of patients with osteoarthritis of the knee is increasing. In the later stages of osteoarthritis of the knee, there is severe damage to the articular cartilage, narrowing of the joint space, joint contracture and deformity, and a very high rate of disability. Total knee arthroplasty (TKA) is an effective treatment for severe osteoarthritis of the knee [1] and has been widely used to treat osteoarthritis of the knee, which can effectively relieve pain and improve joint function. From December 2002 to August 2011, 115 cases of osteoarthritis of the knee were treated with total knee replacement, and the clinical results were satisfactory.
1 Data and methods
1.1 General data
From December 2002 to August 2011, 115 cases of knee osteoarthritis were treated with TKA, 46 men and 69 women, including 19 cases of both knees. 114 cases of osteoarthritis and 1 case of gouty arthritis were diagnosed preoperatively, and the average KSS(I) score was 41±14 (26-58). The average preoperative functional score was 62±14 (51-71). The average preoperative knee mobility was 89° (25° to 125°). Preoperatively, all patients had severe knee pain, deformity, and limitation of motion, and the joint space was significantly narrowed or disappeared on front and side X-rays in the weight-bearing position of the knee, which were consistent with the indications for knee replacement. The prosthesis was selected as the posterior stabilized prosthesis to be applied intraoperatively.
1.2 Preoperative preparation
(1) Preoperative comprehensive physical examination, treatment and control of concomitant diseases (e.g. hypertension, diabetes, chronic obstructive pulmonary emphysema. (2) Pre-operative education of the patient, so that the patient understands the necessity of surgery and prepares the mind before surgery. (3) Prophylactic medication, 30 minutes before surgery and intravenous intravenous antibiotics 5-7 days after surgery. (4) Take frontal and lateral X-ray of the knee joint under weight and axial X-ray of the patella. (5) Preoperative cardiopulmonary function check. (6) Color ultrasound examination of the arteries and veins of the lower extremities.
2. Results
All patients in this group completed the surgery successfully. The average intraoperative bleeding was 100-500 ml after the tourniquet was placed, and the patients were instructed to stand on the third day after surgery and walk with a walker as soon as possible. The average functional score was 89±11 (80-96). The average postoperative knee mobility was 103° (85° to 125°).
The average postoperative knee mobility was 103° (85° to 125°) . The differences between the preoperative and postoperative KSS joint scores, functional scores and knee mobility scores were statistically significant (P<0.05).
3. Discussion
Artificial knee arthroplasty has been continuously improved and perfected, and has gradually developed into a classical procedure for the treatment of knee disorders, achieving recognized clinical efficacy. Currently, total knee arthroplasty is considered to be one of the most effective and successful procedures for the treatment of end-stage or severe knee osteoarthritis [2]. The factors that affect the long-term clinical outcome of artificial knee replacement are twofold: the accurate positioning of the osteotomy and prosthesis implantation in three-dimensional space; and the balance and stability of the isometric gap and soft tissues such as ligaments in the extended and flexed knee [3]. We have found that although there is a standardized procedure for total knee replacement surgery, the actual surgical approach is never static. Only a thorough and detailed surgical plan, tailored to the individual patient, can achieve satisfactory results. Since the advanced stage of knee osteoarthritis is characterized by inversion and flexion deformity, the inversion deformity of the knee, as an example, is discussed as follows.
3.1 Grasp of surgical indications
The knee is a complex joint consisting of the femoral condyle, tibial plateau, and patella, and due to its complex structure, there are strict indications for pain and contraindications [4].TKA is indicated for 1. knee pain with activity limitation, instability and deformity, typically weight-bearing pain, which is ineffective or ineffective with conservative treatment; 2. degenerative joint disease; 3. age of surgery over 65-70 years is appropriate; 4. no heart, lung Important organ diseases, etc. Relative contraindications include: young age, obesity, high knee loading occupation; history of knee infection, etc. Absolute contraindications include: poor general health, poor surgical tolerance and patients with severe diabetes, cardiopulmonary insufficiency; infectious knee inflammation; loss of knee extensor function that cannot be reconstructed, etc. [5]. Because of the high bleeding volume, long operation time and high risk in patients undergoing simultaneous bilateral knee arthroplasty were also considered, we performed only unilateral total knee arthroplasty each time.
3.2 Intraoperative attention to soft tissue balance
The flexion gap is significantly larger than the extension gap during knee flexion contracture, and symmetry of the extension and flexion knee gap can be balanced with a larger flexion gap by releasing soft tissues such as the posterior joint capsule or increasing the amount of osteotomy at the distal femur to increase the extension gap [6].
Excessive bone removal can cause postoperative joint line upward shift, alter joint motion mechanics and affect patellar trajectory [7]. Studies have shown [8] that when the knee is near extension, the primary stabilizing structure of the medial knee under internal and external rotation stress is the medial collateral ligament, and the secondary stabilizing structures are the posterior joint capsule and the cruciate ligament; when the knee is in flexion, the primary stabilizing structure of the medial knee under internal and external rotation stress is the medial collateral ligament, and the secondary stabilizing structures are the cruciate ligament; the primary stabilizing structure of the lateral side is the lateral collateral ligament, and the secondary stabilizing structures is the cruciate ligament and the N tendon. For the knee to be stable in both extension and flexion under internal and external valgus stress, the medial and lateral collateral ligaments should play a primary role in stabilizing the knee joint, while the secondary stabilizing structures play a secondary role. It is possible that the flexion deformity may not be completely corrected intraoperatively or that a residual flexion deformity of 5 to 10° may be allowed in order to avoid excessive distraction injury to the common peroneal nerve [9]. The principles of correction of flexion contracture deformity are based on correct osteotomy, which is achieved mainly by releasing and balancing the soft tissues around the knee joint.
3.2.1 Osteotomy
Correction of the flexion deformity in patients undergoing total knee arthroplasty for internal knee valgus is one of the most important conditions for good postoperative function of the knee joint [10].
Correct femoral and tibial osteotomy is a key step to effectively correct the flexion deformity [11].
We believe that according to the deformity and knee gap narrowing, we first osteotomized 2 mm more than conventional in the femur and 2 mm below the severely injured lateral plateau in the tibia, and then tested the knee extension gap after initial release and osteotomy with an 8 mm gap trial mold. Since the posterior femoral condyle was not yet osteotomized and posterior release was not performed, the total thickness of the tibial osteotomy should be limited to 12 mm. It should be noted that the knee extension problem cannot be solved by increasing the osteotomy alone. Excessive osteotomy will cause relative extension of the knee extension device and weakness of the quadriceps muscle leading to postoperative knee extension, while the farther away from the tibial articular surface, the smaller the bone strength will be and the more likely it will cause postoperative tibial prosthesis loosening, and excessive tibial osteotomy will cause postoperative knee flexion instability. In addition, excessive resection of the distal femur will restrict flexion, although it will facilitate postoperative knee extension. A large amount of bone should not be removed inappropriately for complete correction of the flexion deformity [12]. We believe that an intraoperative knee with 5° of hyperextension and stable internal and external valgus testing is the most desirable result, but this cannot be achieved by massive bone cutting, as this would have a bad effect on the stability and active function of the knee joint.
3.2.2 Soft tissue release
Knee inversion is one of the main manifestations of advanced osteoarthrosis of the knee. We believe that for joint replacement of knee inversion deformity, in addition to accurate osteotomy, correct ligament release and soft tissue balancing is the key to surgery. The goal of total knee arthroplasty is to correct the flexion deformity as much as possible, and if there is still significant flexion deformity after surgery, it will affect ambulation. In terms of walking function, straightening is more important than increasing the range of motion of the joint.
For the intraoperative management of such patients, our procedure is generally to peel off the medial collateral ligament and soft tissue from the upper edge of the tibial tuberosity to the tibial plateau along the medial subperiosteum to the medial tibial crest, and then thoroughly remove the medial bone redundancy, which is the only way to truly loosen the medial collateral ligament, achieve soft tissue balance, and allow the tibial brace to be placed in the correct position, prevent the prosthetic stem from shifting medially, and prevent the tibial prosthesis from This prevents early loosening of the tibial prosthesis due to inaccurate placement of the tibial prosthesis in the center of weight [13]. In patients with internal derangement of the knee, medial and posterior soft tissue release is then performed. It is particularly important to note that the release of the medial soft tissues must be performed under the lateral tibial periosteum because the superficial fibers of the medial collateral ligament are intertwined with the knee capsule and goose metacarpal tendon tissue, and stripping the superficial layer has little effect on the stability of the medial knee joint. The tension of the medial and lateral ligaments must be checked repeatedly during release to determine if the release is adequate,
After complete release of the medial joint capsule and ligaments, the inversion deformity can be corrected [14].
The release of the posterior joint capsule and reconstruction of the posterior fossa of the joint capsule is a key step in the correction of flexion deformity. The release of the posterior joint capsule must be performed close to the femoral condyle and intercondylar fossa and the posterior tibial plateau to avoid damaging the posterior neurovascular and avoid cutting the posterior oblique ligament of the posterior medial knee and the N tendon of the posterior lateral knee [15].
The scale of soft tissue release should be strictly grasped during surgery to achieve balance in flexion and extension of the knee joint and improve the stability of the joint after replacement.
3.2.3 Trajectory of the patellofemoral joint
With the knee fully flexed, the patellofemoral joint stress can be close to 5-7 times the body weight [16]. The trajectory of the patellofemoral joint has complex biomechanical characteristics and is closely related to the contact stress between the patellofemoral joint, the tension of the soft tissues around the knee, and the alignment of the knee extension device, and whether the trajectory of the patellofemoral joint after TKA is good or not directly affects the surgical outcome. If the normal trajectory of the patellofemoral joint cannot be restored after balancing the tension of the medial and lateral patellar support bands, the tendency of the patella to dislocate outward can be corrected by appropriately adjusting the position of the tibial prosthesis. First, the self-positioning method can be used to determine the rotational alignment of the tibial prosthesis according to the direction and degree of rotation of the femoral prosthesis to correct the external rotation deformity of the tibia as much as possible. If the patella still has the tendency of external dislocation, the tibial prosthesis can be placed on the lateral side and in a 3-5° external rotation position, which can obtain the effect equivalent to the internal displacement of the tibial tuberosity and reduce the Q-angle, and reduce the force of pulling the patella to the lateral side for deflection. With a normal ipsilateral hip, a 3-5° external rotation of the femoral and tibial plateau prosthesis does not cause postoperative external rotation of the lower extremity, because compensatory internal rotation of the ipsilateral hip ensures a correct line of force in the postoperative lower extremity [17].
However, if the tibial plateau prosthesis is externally rotated too much, it will cause significantly different degrees of rotation of the femoral and tibial plateau prostheses, resulting in a loss of coordination between the two articular surfaces during postoperative knee flexion and extension activities, affecting the normal alignment of the patellofemoral joint and accelerating the wear of the artificial joint [18].
A very small number of patients still have a tendency to have excessive Q-angle of the knee joint and patellar dislocation. In this case, a patellar ligament transposition can be considered, in which the 1/2 lateral half of the patellar ligament is transposed to the medial side and reconstruction of the patellar ligament stop is performed. The effect is equivalent to the internal displacement of the tibial tuberosity, which reduces the Q angle and at the same time reduces the force of pulling the patella to the lateral side, correcting the tendency of patellar dislocation.
As for whether to perform patellar replacement, it is more controversial in the industry and has been reported by various schools, but we choose not to perform patellar replacement.
4. Rotational alignment of the prosthesis
In artificial knee replacement, after the frontal force line and soft tissue balance are resolved, rotational alignment of the prosthesis becomes the 3rd element [19]. Poor rotational alignment of the tibiofemoral joint after total knee arthroplasty can lead to tibiofemoral subluxation and early wear or rupture of the polyethylene meniscus, as well as affect patellar trajectory and function [20].
The femoral surgical epicondyle axis is a credible marker line for determining the rotational positioning of the femoral prosthesis, but the method of rotational positioning of the tibial prosthesis remains controversial. It has been suggested that the medial edge of the tibial tuberosity to the mid-internal 1/3 line is used as the interval for rotational positioning of the tibial prosthesis [21].
Akagi et al [22] performed CT scans of 39 healthy right knees of Japanese volunteers in the extended position, and concluded that the vertical line passing through the midpoint of the posterior cruciate ligament perpendicular to the axis of the lateral oblique epicondyle of the femur on the tibial projection line is in general agreement with the anterior-posterior axis of the tibia and is a good marker for intraoperative confirmation of rotational positioning of the tibial prosthesis.
Matsui et al [23] found that most patients with internal knee valgus had a combined external tibial rotation deformity and that external tibial rotation increased with increasing internal knee valgus. In addition to using anatomical landmarks as a reference for rotational positioning of the tibial prosthesis, the tibial prosthesis can also be positioned intraoperatively by the “float test”. In other words, the femoral prosthesis is fixed first, and then the tibial prosthesis is placed in a trial mold without fixation, and the natural functional position of the tibial prosthesis rotation is positioned in the extension position after maximum knee flexion and extension activities.
Ikeuchi et al [24] showed that positioning the tibial prosthesis by the “floating test” caused internal rotation of the tibial prosthesis.
We believe that to restore the correct rotational position of the tibia as much as possible, the first step is to determine the rotation of the tibial prosthesis from approximately the medial edge of the tibial tuberosity to the medial 1/3 line, rather than the medial 1/3 line of the tibial tuberosity, as previously thought. At the same time, patients with internal and external knee deformity should be differentiated according to the degree, for example, internal derangement can also be divided into three groups according to Matsui et al [23], and the tibial prosthesis rotation position in patients with mild internal knee deformity is based on the medial edge of the tibial tuberosity, while in severe cases, the medial 1/3 line of the tibial tuberosity is referred to, and in moderate cases, the midline of this zone can be used as a marker [25].
5. Postoperative care and rehabilitation
The main concern after artificial knee arthroplasty (TKA) is the prevention of infection and thrombosis. Infection can be catastrophic, and its presence can mean surgical failure. The incidence of postoperative infection after surgery has been reported to be 1 ~ 2% [26],. We did not encounter infection because of the application of sterile transparent protective film to cover the trauma during intraoperative osteotomy to ensure that bone fragments and blood do not splash back into the trauma, and in the laminar flow operating room with strict aseptic operation. After the operation, we pay attention to the change of sterile dressing, and change the dressing as soon as there is blood leakage. Deep vein can occur in all parts of the veins of the body, with the lower extremity deep vein being the most common. Lower extremity proximal deep vein thrombosis is the main source of pulmonary embolism thromboembolism, so prevention of deep vein thrombosis can reduce the risk of pulmonary artery thromboembolism. Infection and lower extremity deep vein thrombosis (DVT) are major complications after artificial knee arthroplasty. The incidence of infection after TKA has been reported in the literature to be approximately 2% to 4% [27]. Once infection occurs, it will bring catastrophic consequences to the patient and therefore must be given high priority. To prevent the occurrence of lower extremity deep vein thrombosis (DVT), we are delicate in surgical operation, moderate rehydration, and standardize the use of pressure tourniquet, strictly elevate the affected limb after surgery to prevent deep venous reflux obstruction, and encourage patients to get out of bed early and do deep breathing and coughing action [28]. Low-molecular heparin was routinely applied intravenously, and aspirin enteric dissolved tablets were administered orally, and drug side effects were closely detected and changes in the four coagulation items were dynamically observed. Rivaroxaban 10 mg, orally, was applied and started 6-10 hours after surgery (6-10 hours after epidural catheter removal).
The purpose of total knee arthroplasty is to relieve joint pain and improve joint function. Postoperative rehabilitation is an important factor affecting the efficacy of artificial knee arthroplasty. Active postoperative rehabilitation exercises and pain control are essential to prevent postoperative soft tissue contracture, functional recovery and prevention [29]. On the second postoperative day, we actively conducted rehabilitation training for the patient, formulated an individualized rehabilitation plan for the patient, encouraged the patient to perform quadriceps isometric contraction and ankle flexion and extension activity exercises as early as possible, and changed the knee extension position lifting to CPM machine training high training, and within two weeks, the patient’s joint mobility could basically reach 90° and could walk normally with the assistance of a walker, and then gradually transitioned to de-supported Then gradually transitioned to walking with no brace and going up and down stairs.