Technique Of Total Knee Replacement Research Articles

Early clinical effects of total knee arthroplasty with kinematic alignment assisted by patient-specific instrumentation

Objective: To examine the clinical effects of the treatment of knee osteoarthritis patients with kinematic alignment technique of total knee replacement (KA-TKA) assisted by patient-specific instrumentation (PSI). Methods: The clinical data of 14 patients with knee osteoarthritis treated with unilateral KA-TKA assisted by PSI at Department of Orthopaedic Surgery, Beijing Chaoyang Hospital Affiliated to Capital Medical University from May 2018 to August 2019 were analyzed retrospectively. There were 6 males and 8 females, aged 66.6 years (range: 56 to 79 years), 9 left knees and 5 right knees. The operation time, soft tissue release and extra varus or valgus osteotomy were recorded. The data of osteotomy blocks were measured and compared with the corresponding position of the prostheses. The hip knee ankle angle (HKA), the mechanical distal femoral lateral angle (mLDFA) and the proximal tibial medial angle (MPTA) were measured before and 3 months after the operation. The knee joint functional score (KS-F) , knee joint clinical score (KS-C) and the Western Ontario McMaster (WOMAC) Osteoarthritis Index were recorded and compared by paired t test or Wilcoxon non-parametric test. Results: The operation time was (81.8±16.9) minutes (range: 60 to 115 minutes), 2 cases were manually increased varus osteotomy by 2 mm and 1 patient received lateral retinaculum release. There was no extra medial or lateral soft tissue release. Intraoperative measurement of the resection showed that the femoral side mismatch was within 2 mm. The medial and lateral condyle, the medial and lateral posterior condyles were relatively overcut by 0.50 mm, 0.21 mm, 0.93 mm, and 0.71 mm, respectively. The tibial side mismatch was within 1.5 mm, the medial and lateral plateau were relatively undercut by 0.43 mm and 0.32 mm. HKA was corrected from (8.8±5.6) ° to (1.6±4.3) ° (t=20.723, P=0.000) .KS-C improved from 28.21±13.47 preoperative to 78.07±8.01 postoperative (t=-16.570, P=0.000); KS-F improved from 41.00±15.25 preoperative to 84.93±10.85 postoperative (t=-14.675, P=0.000).WOMAC Osteoarthritis Index decreased from 53.5 (25.75) (M(Q(R))) preoperative to 5.5 (5.25) postoperative (Z=-3.297, P=0.001) .No statistically significant difference was found in mLDFA and MPTA before and after surgery. No significant patellofemoral complication was recorded during follow-up time. Conclusions: PSI assisted TKA resection has high accuracy. KA-TKA aims to restore the native anatomy of the knee joint, only corrects the malalignment of lower extremities caused by articular cartilage wear, with less interference to soft tissues, easy to obtain satisfactory knee joint laxity and has a promising early clinical effect.

Computer-assisted surgery in total knee replacement: advantages, surgical procedure and review of the literature.

Introduction: Total knee replacement (TKR) is one of the most frequent orthopaedic procedures performed every year. At the same time 20% of patients who underwent TKR are not satisfied with the outcome. The reasons are unknown; we think that a mechanical alignment beyond 3° of varus-valgus can represent the most important cause of failure of TKR and consequently patient dissatisfaction. Materials and Methods: Neutral mechanical alignment is the main goal in every TKR: this can be achieved through different tools, such as extramedullary and intramedullary guides, patient-specific instrumentation (PSI) and computer-assisted surgery (CAS). The aim of this review is to compare the different alignment techniques in TKR, to describe CAS procedure and CAS results in recent literature. Results: Regarding the intramedullary guide, there is an increased risk of fatty embolism; there are great limitations on its use, or even impossibility, in cases of bone deformity and sequelae of trauma. Regarding the extramedullary guide, it becomes more difficult to use in cases of great obesity or increased soft-tissue volume around the tibia. PSI for TKR has been introduced to improve alignment, reduce outliers, operation time and the risk of fatty embolism by avoidance of intramedullary canal violation. Recent randomized controlled trials and meta-analysis proved no advantage of PSI in improving mechanical axis and implant survivorship. Discussion: CAS has provided to be a useful tool in assisting the surgeon to achieve more accurate post-operative mechanical axis through precise and reproducible bone cuts and ligament balancing. Two meta-analyses definitively proved that CAS technique improves mechanical axis and implant survivorship and one recent meta-analysis demonstrated that CAS provides better mechanical alignment and higher functional scores at short-term follow-up. (www.actabiomedica.it)

Is axial shape of distal femur different in normal and osteoarthritic female patients?

This study aims to investigate whether the axial shape of the distal femur is different between normal and osteoarthritic female knees using statistical shape analysis. A total of 126 knee magnetic resonance images of 126 female patients were examined in this study conducted between May 2013 and May 2014. Patients were divided into two groups as study and control groups. The study group consisted of 41 patients (median age 65 years; min. 36 - max. 88 years) who were determined to have knee osteoarthritis, while the control group consisted of 85 patients (median age 43 years; min. 20 - max. 81 years) without knee osteoarthritis. Anatomic and constructive landmarks were selected and marked on each two-dimensional digital image in the axial section of the distal femur. The mean axial shapes of the distal femur were compared between the groups by statistical shape analysis. Shape deformations were investigated by thin plate spline analysis. There were significant differences between the groups regarding the axial shape of the distal femur. Maximal deformation was observed in the femoral notch area. This study showed that there are deformations in the axial shape of the distal femur in female patients with knee osteoarthritis. Further studies are required to determine whether these differences are important for implant design and surgical technique of total knee replacement.

A review of rapid prototyped surgical guides for patient-specific total knee replacement

Improvements in the surgical technique of total knee replacement (TKR) are continually being sought. There has recently been interest in three-dimensional (3D) pre-operative planning using magnetic resonance imaging (MRI) and CT. The 3D images are increasingly used for the production of patient-specific models, surgical guides and custom-made implants for TKR. The users of patient-specific instrumentation (PSI) claim that they allow the optimum balance of technology and conventional surgery by reducing the complexity of conventional alignment and sizing tools. In this way the advantages of accuracy and precision claimed by computer navigation techniques are achieved without the disadvantages of additional intra-operative inventory, new skills or surgical time. This review describes the terminology used in this area and debates the advantages and disadvantages of PSI.

The Use of Patient-Specific Intra-Operative Guides for Total Knee Arthroplasty (TKA)

Purpose: We describe a new technique of total knee replacement using patient-specific guides. Postoperatively, extremity and component alignment were evaluated by full-length leg x-rays and CT scans. Material and methods: 5 patients who underwent Total Knee Replacement with this technique were included in the study. In every patient, a preoperative MRI was taken. This MRI scan leads to a patient-specific plan of implant size and positioning. The surgeon has the ability to alter the planning before the approval and manufacturing of guides (BIOMET, Vanguard Signature Personalised Arthritis Care). During the operation, the patient-specific guides find their unique position on the patient’s knee, providing exact pin placement for the distal resection guide, 4-in-1 cutting block and the proximal tibial cutting guide. The advantage of this method is providing each patient with a specific guide depending upon the proper anatomy. Intramedullary access for axis alignment is unnecessary. By providing specific guides for individual knees, each knee is dealt with differently, corresponding to its native anatomy. Perioperative time of surgery and postoperative implant position were evaluated by standing antero-posterior and lateral x-rays of the knee as well as a CT scan for rotational alignment of components. Results: The mean operative time is 65.6 minutes. The mean coronal femoral component angle is 89.2. The mean sagittal femoral component angle is 88.8. The mean coronal tibial component angle is 89.4. The mean femoral rotation angle is 0.6 degrees, and the mean tibial rotation angle is 1.2. Conclusions: We conclude that this novel technique hereby described has major benefits: less operative time and proper implant positioning, but more prospective studies are mandatory.

Computernavigierter Gelenkersatz am Knie mit dem Orthopilot®

Reproducible, precise implantation of a bicondylar knee prosthesis considering size of implant, axial conditions in coronal and sagittal planes, rotation, and ligament tension in extension and flexion. Progressive painful gonarthrosis, when conservative treatment is no longer an option. Revision of unicondylar prosthesis. General contraindications to bicondylar knee replacement. Revision after bicondylar replacement. Severe limitation of hip joint mobility, e.g., after arthrodesis of the hip joint or ipsilateral hip joint ankylosis. Morbid obesity. Approach to the knee joint for alloarthroplasty. Placement of the screws and fixation of the infrared reflectors at femur and tibia. After adjustment of the double camera, collection of kinematic data via standardized motion patterns and identification of predetermined anatomic landmarks at the knee and ankle joint. By means of this data, controlled resection of the tibia, determination of the ligament tension in extension and flexion, planning of the femoral osteotomies, controlled distal resection of the femur. Following intraoperative verification of the distal femur resection, navigation of the position of the femur to complete femoral resection. Placement of the trial components, determination of the tibial onlay thickness, adjustment of the rotation of the tibial component, and final preparation of the tibial shaft. Preparation of the patella by resection of osteophytes, denervation, and possibly onlay patellar resection using a saw. Finally, implantation of the tibial component (cemented or noncemented), the tibial onlay, the femoral component (cemented or noncemented), and possibly cementation of the patellar onlay. After hardening, control of knee movement in straight position and wound closure in layers. Early functional treatment using continuous passive motion device. Pain-adapted increase of weight bearing. Low-molecular-weight heparin for 5-6 weeks. Meanwhile, several studies have demonstrated that computer navigation helps to provide more accuracy in implant positioning, compared with conventional techniques in total knee replacement. Long-term survival of the implants promises to be superior after physiological leg axis restoration. Own results: 100 consecutive implantations: average duration of surgery 80 min, blood loss 360 ml, one deep infection (healed after early revision), one arthrofibrosis requiring revision surgery, average range of motion on the day of discharge 110 degrees in flexion (90-120 degrees) and full extension, after 3 months average 125 degrees in flexion (90-140 degrees). No clinical signs of instability. Postoperative radiologic evaluation with standard radiographs of the knee joint in coronal and sagittal planes took place right after surgery and again after 3 months.

Comparison of cementing techniques of the tibial component in total knee replacement

A few studies have shown that cementing the stem enhances fixation of the tibial baseplate in total knee replacement (TKR). Even the horizontal technique has been shown to provide good fixation. We used radiostereometry to study migration of the tibial component in 30 knees operated with Profix TKR. The knees were randomised for either complete (both under the baseplate and around the stem) or horizontal (only under the baseplate) cementing of the tibial component. At two years the tibial baseplate rotated externally a median of 0.18 degrees in the uncemented stem group and internally a median of 0.23 degrees in the cemented stem group. The tibial baseplate subsided 0.14 mm in the cemented stem group, and no translation was seen in the uncemented stem group. The differences in migration were small and probably without clinical significance. The findings do not favour either of the cementing techniques in TKR.

Total knee replacement performed with either a mini-midvastus or a standard approach

We report the clinical and radiological results of a two- to three-year prospective randomised study which was designed to compare a minimally-invasive technique with a standard technique in total knee replacement and was undertaken between January 2004 and May 2007. The mini-midvastus approach was used on 50 patients (group A) and a standard approach on 50 patients (group B). The mean follow-up in both groups was 23 months (24 to 35). The functional outcome was better in group A up to nine months after operation, as shown by statistically significant differences in the mean function score, mean total score and the mean Oxford knee score (all, p = 0.05). Patients in group A had statistically significant greater early flexion (p = 0.04) and reached their greatest mean knee flexion of 126.5 degrees (95 degrees to 135 degrees ) 21 days after operation. However, at final follow-up there was no significant difference in the mean maximum flexion between the groups (p = 0.08). Technical errors were identified in six patients from group A (12%) on radiological evaluation. Based on these results, the authors currently use minimally-invasive techniques in total knee replacement in selected cases only.

Survey of current cementing techniques in total knee replacement

Current techniques in total knee replacement (TKR) vary greatly. Cementing techniques in TKR are no exception. Identification of current trends would aid ongoing research into future developments. A questionnaire was sent to all orthopaedic surgeons in Queensland, Australia. A range of factors influencing cementing techniques for the tibial plateau were investigated. Eighty-five percent of questionnaires were returned. Ninety-one percent of surgeons regularly cement the tibial plateau, 90% use some form of lavage prior to cement application, 95% of surgeons apply cement by hand only. Techniques aimed at increasing cement penetration (cement gun, intraosseous suction) are used infrequently. In contrast to total hip replacement, measures are not often taken to ensure that there is penetration of cement or a complete cement mantle into the tibial plateau in TKR. This may be because of a perceived lack of evidence in modern literature. This study also illustrates the wide variation in technique in a relatively common orthopaedic operation.

THE KNEE JOINT IN RHEUMATOID ARTHRITIS

The knee joint is commonly damaged in polyarticular rheumatoid arthritis. Surgical management depends on the preservation of the articular cartilage and degree of synovitis. Arthroscopic synovectomy is performed in intractable synovitis with cartilage sparing. Technique of total knee replacement is more complex because of bone and soft-tissue damage in rheumatoid arthritis, and complications are more common, particularly infection. Overall, long-term results with knee arthroplasty have been excellent in rheumatoid arthritis, with improved function and reduction in pain in the vast majority of patients.

Total knee replacement technique: what is not in the brochure

sympathetic block pain unit consultation (2) Causes of a painful TKR A. Intra-articular problems loose bodies overhanging component patellar clunk recurrent hemarthrosis gout/CPPD/RA persistent synovitis B. Periarticular problems pes anserine bursitis patellar tendinitis stress fracture heterotopic ossification C. Malalignment MCL strain in valgus knee tibial overload in varus knee rotational impingement patellar subluxation D. Instability flexion PCL sag anterior knee pain increased poly wear ‘start up pain’ medial/lateral global E. Systemic problems ipsilateral hip vascular claudication F. Neurologic complications peroneal entrapment reflex sympathetic dystrophy L3/4 HNP neurogenic claudication (spinal stenosis) 6. Patellar problems avascular necrosis stress fracture subluxation impingement patellar clunk H. Stiff knee limited pre-op motion tight PCL residual flexion contracture aggressive fibrous tissue response: 1. Patient issues unrealistic expectations limited pre-operative changes depression family dynamics.

Prediction of total knee motion using a three-dimensional computer-graphics model

Twenty-three knees were sectioned, digitized, and standardized to determine the ‘average’ three-dimensional bony geometry and ligamentous attachments. Data on normal knee motion were obtained from a cadaveric study. An algorithm was written to simulate three-dimensional patella motion. Verification of the knee model was achieved by determining femoro-tibial and patello-femoral contact locations, as well as ligament length patterns, and comparing the results with published data. The criterion for maximum predicted knee motion with a prosthesis in place was the length of the posterior cruciate ligament. Three total knee replacement surfaces were mathematically generated: flat, laxity and conforming. A greater flexion angle was obtained with a flat tibial surface than for the laxity or conforming. Posterior tibial component displacement increased the range of motion, but only slightly. For all tibial surfaces, increased range of motion was achieved with a 10° posterior tilt of the tibial tray. Anterior femoral component displacement increased motion due to reduction in posterior cruciate tension during flexion. The results are applicable to the design and surgical technique of total knee replacement.