Technical Considerations in Total Knee Arthroplasty (original) (raw)

Total knee arthroplasty in patellectomized patients

The Journal of Arthroplasty, 1993

Thirty-two total knee arthroplasties (TKAs) in patellectomized patients were evaluated with recent clinical and radiographic examinations. Eighteen patients had a primary TKA with a mean follow-up period of 49 months, and 14 patients had a revision TKA with a mean follow-up period of 36 months. A control group of 13 TKA patients with intact patellae were randomly generated but matched for age, sex, follow-up data, diagnosis, and prosthesis. Posterior cruciate ligament-retaining types of prostheses were used in the primary knees, while the revision knees underwent arthroplasties with the more constrained, posterior cruciate ligament-substituting prostheses. All knees were evaluated based on the Knee Society's clinical and radiographic scoring system. In addition, 18 patients (9 primary, 9 revision) underwent isokinetic dynamometer testing for quantitation of peak quadriceps and hamstring torque. The knee score, indicative of pain relief, averaged 82.5 in the primary group (16 good/excellent, 1 fair, I poor), 86.5 in the revision group (12 good/excellent, 1 fair, 1 poor), and 93.9 in the control group (13/13 excellent). The function score averaged 59.7 in the primary group (6 good/excellent, 6 fair, 6 poor), 60.0 in the revision group (5 good/excellent, 2 fair, 7 poor), and 80.9 in the control group (12 good/excellent, 1 fair). The lower function scores predominantly reflected the patients" difficulty in independently climbing or descending stairs. This was also reflected in their higher flexion to extension peak torque ratios. There was one failure in the 9 primary group reqniring a revision and one failure in the revision group requiring a knee fusion. There was no radiographic evidence of impending failure in any of the remaining knees. No clinical or radiographic differences were found between the patients with osteoarthritis or rheumatoid arthritis. Although the knee and function scores were lower in the patellectomized patients, the overall results were generally satisfactory without a high incidence of failures. Satisfactory results were obtained in the primary TKAs using the minimally constrained prostheses when the posterior cruciate ligament was intact. Revision TKAs, in which the posterior cruciate ligament was absent, also demonstrated satisfactory results with the more constrained, posterior cruciate ligament-substituting prostheses.

Studies in Total Knee Arthroplasty

2010

The presented thesis studies the knee arthroplasty, in order to contribute to the improvement of knee prostheses. The main subjects treated in the research activity consist in: biomechanical study of the knee joint; 3D reconstruction of the knee joint starting from the ct images; conception and design of new models of partial and total knee prostheses; experimental motion analysis of patients having different pathologies (implanted and nonimplanted); manufacturing of the designed models of knee prostheses; testing of the manufactured prostheses.

Surgical approaches in total knee arthroplasty (Protocol)

Cochrane Database Syst Rev, 2005

Total knee replacement surgery begins with correct planning of both the incision and the exposure of the joint. Indeed, these are factors that are just as crucial to an optimal outcome as choosing the right implant, positioning the components, and balancing the ligaments. While it is true that the standard incision and arthrotomy (with which we are most familiar) will, in most primary implant cases, provide adequate joint exposure, it is also true that cases characterized by certain conditions, such as previous cutaneous incisions, a stiff knee or patella baja, present specific skin and exposure problems that need to be recognized, planned for and overcome. This is the protocol for a review and there is no abstract. The objectives are as follows: To determine, based on evidence from randomised controlled trials, the effects of surgical approach on patient outcome following TKA. Null hypothesis: There is no difference in outcome between surgical approaches for TKA.

Radiological Evaluation of Total Knee Arthroplasty.pdf

Objective: X-Ray analysis of a subset of TKA performed using a standard posterior cruciate ligament (PCL) retaining cemented technique to study the component malposition, overall post-operative alignment and mechanical loosening with respect to components positioning during follow-up period. Patients and Methods: This is a prospective study where we radiographically evaluated twenty-six primary TKAs (15 right and 11 left) in 20 patients (six patients received two stage bilateral total knee replacement) performed between July 2004 and December 2005. There were a total of 13 women and 7 men. The mean age at the time of the operation was 68 years and the follow-up period ranged from 18-32 months. The indication for knee replacement in all cases was advanced osteoarthritis. Radiographs were done immediately postoperative, at 6 weeks, at 3 months, at 6 months and then every year after surgery, and each time were compared to the postoperative controls. Observations: The overall alignment was acceptable in 19 knees, 3 had excessive valgus and 4 had varus alignment. At the last follow-up which was up to 32 months in some cases, none of the cases developed loosening as evidenced by non appearance of radiolucent zones or shifts in the position of the components. Moreover, the seven cases with joint malalignment didn’t show signs of aseptic loosening within the available follow-up period. For the patellar angle, the mean tilt angle was 12° ± 6°. In 17 knees the patellar prosthesis was displaced superiorly, and in seven cases there was medial displacement of the patellar prosthesis Conclusion: Evaluation of total joint arthroplasty must be clinical, radiological and with annual intervals, in order to discover early failure signs. Proper alignments are critical for achieving good results thus keeping loosening to a minimum. Concerning the present study, aseptic loosening was not a complication of the total knee arthroplasty evaluated at a follow-up period of up to almost three years in some cases, including those cases with documented postoperative joint malalignment.

Medium-term evaluation of total knee arthroplastywithout patellar replacement

Revista Brasileira De Ortopedia, 2013

Objective: To mid-term evaluate patients who were submitted to total knee arthroplasty without patellar resurfacing. Methods: It was realized a retrospective cross-sectional study of patients who were submitted to total knee arthroplasty without patellar resurfacing. In all patients clinical examination was done based on the protocol of the Knee Society Scoring System, which assessed pain, range of motion, stability, contraction, knee alignment and function, and radiological evaluation. Results: A total of 36 patients were evaluated. Of these, 07 were operated only on left knee, 12 only on right knee and 17 were operated bilaterally, totaling 53 knees. Ages ranged from 26 to 84 years. Of the 53 knees evaluated, 33 (62.26%) had no pain. The maximum flexion range of motion averaged 104.7°. No knee had difficulty in active extension. As to the alignment for anatomical axis twelve knees (22.64%) showed deviation between 0° and 4° varus. Thirty-nine (75.49%) knees showed pace without restriction and the femorotibial angle ranged between 3° varus and 13° valgus with an average of 5° valgus. The patellar index ranged from 0.2 to 1.1. Conclusion: Total knee arthroplasty whitout patellar resurfacing provides good results in mid-term evaluation.

Eliminating patellofemoral complications in total knee arthroplasty

The Journal of Arthroplasty, 1999

This study reports the minimum 5-year follow-up of our experience with the Duracon Total Knee Arthroplasty System. A total of 121 consecutive total knee replacements using the Duracon system (Howmedica, Rutherford, N J) were performed in 104 patients. Three patients died before the 5-year follow-up and were excluded from the final evaluation. The remaining 118 knees (10i patients) were assessed at a mean follow-up of 65 months (range, 60-80 months). The knee diagnoses were osteoarthritis in 97 patients, rheumatoid arthritis in 2 patients, osteonecrosis in 1 patient, and pigmented villonodular synovitis in 1 patient. The mean age was 70 years (range, 28-85 years). There were no reoperations for aseptic loosening, and there have been no reoperations for patellofemoral problems. At final follow-up evaluation, 112 knees (96%) had good or excellent results, and 6 knees (4%) had poor clinical results or went on to revision. For the surviving knees, the preoperative Knee Society objective score improved from a mean of 52 points (range, 20-72 points) to a final follow-up mean of 94 points (range, 66-100 points). Five knees needed reoperations: 2 knees in I patient because of acute hematogenous infection at 12 months, 1 knee because of a supracondylar femur fracture, 1 because of a patellar tendon rupture, and 1 to increase polyethylene thickness because of instability. The lack of aseptic loosening at the minimum 5-year follow-up compares favorably with any cemented or cementless series of knee replacement. The almost complete absence of patellofemoral complications in this series also indicates that the design changes, with particular attention to the trochlea design and patellofemoral contact throughout full flexion, have achieved their intended purpose. The results are encouraging at midterm, awaiting true long-term (15-20 years) follow-up.

Revision Total Knee Arthroplasty

Clinical Orthopaedics and Related Research, 1982

Revision total knee arthroplasty can be very successful if careful preoperative planning has been carried out and the surgeon is equipped to handle potential problems encountered with restoration of static alignment, stability, and deficient bone stock. Special femoral and tibial component extractors are indispensable tools. A high-speed burr is helpful. Posterior cruciate ligament-preserving prostheses often can be used, but prostheses with extra degrees of constraint must be available. Long-stemmed components for both the femoral and tibial sides should be available. Access to a bone bank to obtain allogeneic bone for grafting is essential. The surgeon must be familiar with techniques other than bone grafting for restoration of deficient stock, such as the use of bone screws and cement, custom-augmented components, and metal wedge spacers.