[Total prosthesis of the knee].
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1. Cementation in total knees is here to stay. 2. Future improvements will lie in the area of implant interfaces--in the near term by improving our polyethylene. 3. Cementless knees, with or without HA, may be indicated in the young, more active patient and where economic concerns have no impact on prosthetic selection.
A retrospective analysis was performed of 12 patients who required soft-tissue coverage of an exposed or infected total knee prosthesis between 1982 and 1989. All knees had skin closure with medial gastrocnemius muscle flaps. At a mean follow-up period of 41 months, all patients who were treated for infected prostheses with removal of the implant, intravenous antibiotics, and muscle flap closure had an excellent clinical result with complete skin coverage and no infection. Five of the six patients went on to successful reimplantation. Of the patients with an exposed prosthesis, five of six had an excellent outcome with retention of the prosthesis. Thus, 11 of 12 patients (92%) who had medial gastrocnemius flap coverage of an exposed or infected knee prosthesis had an excellent outcome, with ten of 12 patients (82%) retaining their prostheses or having a successful reimplantation. No medial gastrocnemius flap failed after standard primary or revision total knee arthroplasty. Gastrocnemius muscle flaps provide excellent soft-tissue coverage of exposed or infected knee prostheses and facilitate surgical care of this difficult problem.
UNLABELLED: Ciprofloxacin, a quinolone antibiotic drug, binds to DNA topoisomerase IV and DNA gyrase of various bacteria. Thus ciprofloxacin labeled with (99m)Tc could potentially act as a specific marker allowing discrimination between infection and sterile inflammation. We evaluated these properties on a rabbit model of prosthetic joint infection previously validated. We compared the images obtained in 2 groups of animals: rabbits with infected (G1; n = 6) and uninfected (G2; n = 7) prosthesis. METHODS: Partial right-knee arthroplasty was performed on 13 New Zealand White female rabbits, with a tibial silicone-elastomer implant fitting into the intramedullary canal of the tibia. After the surgical wound was closed, 10(7) cfu of a clinical strain of methicillin-susceptible Staphylococcus aureus were injected into the joint in G1 rabbits. G2 rabbits were injected with sterile saline. No antibiotic therapy was given to the animals. (99m)Tc-ciprofloxacin planar imaging was performed on days 5, 12, and 19 after surgery, and after 3 mo in 1 uninfected rabbit. Images were obtained 1, 4, and 24 h after injection (147 +/- 13 MBq). RESULTS: In G1, increased right knee (99m)Tc-ciprofloxacin uptake was observed in 3 of 5 rabbits on day 5, and in all cases on days 12 and 19. Killing of the animals revealed purulent arthritis, osteitis, and tibial myelitis. In G2, significant right-knee uptake was found on days 12 and 19 in 5 of 6 rabbits, and after 3 mo in 1; all sets of images were negative in 1 animal. Bacteriologic studies after the animals were killed were negative in G2. Mean right/left knee uptake ratios on day 19 (4-h images) were 1.8 +/- 0.4 in G1 versus 1.4 +/- 0.3 in G2 (not significant). Late images did not discriminate between infected and uninfected arthroplasty. CONCLUSION: Results of (99m)Tc-ciprofloxacin imaging in rabbits with infected/uninfected knee prosthesis suggest good sensitivity but lack of specificity for the detection of S. aureus infection.
A 3D knee model was developed in order to evaluate the mechanical behaviour during flexion of condylar-type knee prosthesis. Based on the total energy minimization principle, it takes into account the articular surfaces (the tibial surface being deformable), the body weight, and the patello femoral joint. It generates the kinematics of the joint, the motion of the centre of contact, the quadriceps forces, the pressure distribution on the tibial plateau, and ligament lengths and forces between 0 and 120 degrees of flexion. The results for ten digitized knees and the commercially available prostheses are presented. They are in general agreement with experimental results published in the literature. It is concluded that this computer program may be, within its limitations, a useful tool in the preliminary evaluation of new condylar-type knee prosthesis designs.
BACKGROUND: Infected tumor endoprosthesis of the knee in young patients can prove to be challenging. Common procedures are débridement and prosthesis reimplantation, amputation, revision arthroplasty, and arthrodesis. CASE PRESENTATION: We report the case of a 44-year-old man treated by arthrodesis followed by callus distraction after removal of an infected tumor mega prosthesis (Kotz type). Callus distraction was performed over a distance of 11 cm in 4 months using a femorotibial intramedullary nail with an external traction rope-winch system. METHODS AND FOCUS: The clinical, radiological, technical, and therapeutic features are discussed.
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OBJECTIVE: To clinical evaluate the results of total condylar knee arthroplasty using three types of Chinese knee prosthesis. METHODS: Hundred and two knees (in 92 patients) arthroplasty were performed in our department during the 14 years (April 1981-November 1995) were analyzed. The follow-up period averaged 64.4 months. Eight cases had died and 14 cases were lost of follow-up, leaving 80 knees in 70 patients for clinical evaluation. The clinical results were evaluated according to Hospital for Special Surgery Rating System. RESULTS: The average preoperative score was 47.65 and the postoperative score was 90.23. Almost all patients achieved significant pain relief after operation. Sixty-one of the 70 patients (87%) reported that they satisfied or very satisfied with the results of surgery. There were 6 failures. One was due to deep infection, one with loose patellar component, and four directly related to either improper selection or technical reasons. CONCLUSIONS: Total condylar knee arthroplasty with Chinese knee prosthetics gives a satisfactory grade of pain relief and movement of the operated knee. Chinese knee prosthetics is safety and durable.
There are few reports in the literature that deal with the results of total knee arthroplasty in the younger patient. The present study was undertaken to evaluate the results of total knee arthroplasty in patients under the age of 55 years. Ninety-three knee arthroplasties in 62 patients were performed between 1974 and 1982. The preoperative diagnosis was rheumatoid arthritis in 76 knees and osteoarthritis in 17 knees. The total condylar knee prosthesis was used in all knees. Defects in the tibial plateau were noted in 13 knees, and supplemental support was required. Ninety knees (17 with osteoarthritis and 73 with rheumatoid arthritis) were available for follow-up study at a mean of 6.1 years. The knee rating for the entire group was 87.1. The subgroup scores for the osteoarthritis and rheumatoid arthritis groups were also 87.1. Roentgenographic evaluation revealed a lucency rate of 30%. Two implants were found to have global radiolucencies and were considered loose. Survivorship analysis resulted in a cumulative survivorship rate of 96% at ten years for the entire group. These results are comparable to the long-term results of total knee arthroplasty in the older patient and better than the results of total hip arthroplasty in the younger patient. Total knee arthroplasty in the younger patient is a reliable and durable procedure but should be used with caution despite the excellent results reported here.
It is our belief that this is the first histologically documented case of popliteal cyst secondary to early failure of a cementless knee prosthesis, that occurred after 4 years. The walls of the cyst presented with granulomatous reaction to polyethylene particles. In prosthetic reimplantation successive to excision of the cyst we observed a recurrence of cysts and osteointegration of the prosthetic components, that made reimplantation difficult. Histological assessment of the synovial tissue, periprosthetic tissue and underlying bone showed granulomatous reaction to polyethylene debris. A "tumor" in a patient that has a knee prosthesis can be caused by implant failure. In cases of early failure wear forms large particles and their migration at the bone-prosthesis interface may be obstructed and thus cause a different biological response. If reimplantation is necessary osteointegration of the implants may make surgery difficult.
To assess the causes of failure in a blood saving program and the consequent need for homologous transfusions during major orthopedic surgery, data were collected from six orthopedic centers where an autotransfusion program was carried out from 1992-1994. The 1,576 (1,016 female and 560 male) patients studied (average age 63.6 +/- 10 years) were treated either for total hip prosthesis (1,144 pts) total knee prosthesis (212 pts), plate and screw removal plus hip prosthesis (8 pts), hip revision (cup 48 pts, stem 10 pts, cup plus stem 146 pts) and total knee revision (8 pts). Ninety percent of patients did not undergo homologous transfusions, which was significantly connected to: male sex (8% versus 11.7% p = 0.02), younger age (63.2 vs 66.9 years, p = 0.0001), higher weight (male 76 vs 70.7 Kg. p = 0.003, female 65.6 vs 61.9 Kg. p = 0.0003); higher baseline Hb (13.9 vs 12.8 g/dl, p = 0.0041), shorter operation time (110 vs 128 minutes, p = 0.0001); use of indobufen for antithromboembolic prophylaxis (indobufen 4.6% vs heparin calcium 15.2% vs low molecular weight heparin 9% p = 0.0001). On the contrary, the factors favoring homologous transfusions were: peripheral anesthesia (spinal and epidural 15.3% vs general 9.3% vs integrated 9.8% p = 0.016), total hip or knee revision, fixation device removal before hip prosthesis, systemic hypertension and coronary heart disease.
In a long-term follow-up of 55 Marmor knee arthroplasties in patients with rheumatoid arthritis operated on between 1975 and 1977, the radiologically visible indicator wire was used to identify the position of the tibial components. The survival rate of the prostheses at 15 years was 0.71, and the revisions were evenly distributed over the observation period of 16 years. No significant relationship was found between the slope of the tibial components postoperatively and the survival of the prostheses. However, a postoperative valgus angle of the leg of 3 deg or more tended to increase the risk of revision (RH = 2.7, 95% CL = 0.8-8.9). The patient's sex, affected side or weight did not influence prosthesis survival.
OBJECTIVE: To investigate the effect of inserting a Fuji pressure sensitive film into an artificial tibiofemoral joint on the actual contact mechanics. DESIGN: The experimental measurement and finite element analysis were used.Background. Although Fuji pressure sensitive film was widespread used for measuring the contact characteristics of artificial joint, how this measurement approaches actual contact characteristics has not yet been studied extensively. METHOD: Two three-dimensional finite element models of an artificial tibiofemoral joint were constructed. The with-film-model was used to mimic the experimental setup and was verified by comparing the contact area and pressure on the simulated film calculated from finite element analysis to the measured one from the Fuji film (ultra-super low and medium grades) in the experimental test. Then the with-film-model was modified to the without-film-model in which the simulated film was removed. The contact characteristics on the film calculated from the with-film-model were represented to the measured one and the contact characteristics on the tibial component calculated from the without-film-model were represented to the actual one. The measured and actual contact characteristics were studied to investigate the effects of Fuji film on the actual contact characteristics in the tibiofemoral joint of knee prosthesis. RESULTS: The contact characteristics calculated from with-film-model was reasonable agreement with measured one by Fuji film in the experimental test. The maximum difference is 13% in maximum contact pressure under a load of 3000 N. The maximum difference of contact area and pressure between the model simulating actual contact circumstance and the model with inserting a Fuji film between contacting surface are 2.4% and 14% respectively. CONCLUSION: This study revealed that contact area and pressure of the tibiofemoral joint of knee prosthesis measured by Fuji pressure sensitive film could be simulated by finite element analysis. The measurement of contact area in the artificial joint by using ultra-super low grade Fuji film is overestimated its actual contact area by 1.2-2.4%, but the measurement of contact pressure by using medium grade Fuji film is underestimated its actual contact pressure by 8-14%. RELEVANCE: This study revealed that the ultra-super low grade Fuji film is a reliable sensor to measure the contact area and the medium grade film would underestimate its actual contact pressure in the artificial tibiofemoral joint. This finding can provide a better understanding of the reliability of Fuji film to measure the contact characteristics of artificial joint in the experimental test.
UNLABELLED: The aim of this study was to evaluate the diagnostic value, in suspected infectious prostheses, of (99m)Tc-labeled hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) leukocyte scintigraphy interpreted with the addition of a semiquantitative analysis. METHODS: By means of a retrospective review, we included a group of 78 consecutive patients with suspected hip or knee prosthesis infection. We performed 91 (99m)Tc-HMPAO-leukocyte scintigraphies and examined 95 localizations that were suspect. Images were acquired at 3 different time points after the injection of the labeled leukocytes: 50 min (early images), 4 h, and 24 h (late images). The scintigraphic examinations were independently evaluated by 3 observers; qualitative and semiquantitative analyses were performed. The final diagnosis of infection was based on surgical, histologic, and bacteriologic data and follow-up. RESULTS: On qualitative analysis, sensitivity, specificity, and accuracy were 80.4%-87%, 65.3%-71.4%, and 75.8%-77.9%, respectively. On semiquantitative analysis, sensitivity, specificity, and accuracy were 95.6%, 95.8%, and 95.8%, respectively. The analysis of 95% confidential intervals showed statistically significant differences in specificity and accuracy between semiquantitative and qualitative analyses. CONCLUSION: In those patients who underwent (99m)Tc-HMPAO-leukocyte scintigraphy for suspected hip or knee prosthesis infection, the addition of a semiquantitative evaluation to the qualitative analysis of early and late images leads to a significant improvement in both specificity and accuracy.
OBJECTIVE: To determine the outcome of cementless hydroxyapatite-coated total knee prosthesis in rheumatoid patients. DESIGN: Analytical. PLACE AND DURATION OF STUDY: University of Yamanashi Hospital, Japan, from October 1999 to September 2002. PATIENTS AND METHODS: Twenty total knee arthroplasties using HA-coated Scorpio Superflex CR and Delta 7000 series were performed in 17 rheumatoid patients. Pre and postoperative results were compared using JOA scores. RESULTS: Male: female ratio was 16:1, average age was 67 years and mean duration of follow-up was two years. JOA scores improved significantly (p<0.05) postoperatively from an average of 37 to 80. Varus and valgus angular deformities improved significantly and 90% of the knees had alignment between zero and 5 degrees of valgus angulation with an average tibiofemoral angle (FTA) of 172. The radiographic findings revealed no radiolucent lines at two years follow-up. Distal femur osteolysis was not observed. CONCLUSION: The clinical results were excellent at 2-year follow-up, which are in agreement with other reports using hydroxyapatite-coated knee prosthesis.
The GSB II (Sulzer Medica, Winterthur, Switzerland) knee prosthesis ranks between the minimally constrained condylar prostheses and the fully constrained hinges. The senior author (T.R.S.) used this prosthesis in 47 patients (54 knees) with a maximum follow-up of 18 years (mean, 7.8 years). The mean patient age was 75 years (range, 61-94 years). The 10- and 18-year cumulative life-table survival rates were 95.7% and 88.1% for prosthesis removal or infection, 87.4% and 76.8% for patient dissatisfaction, and 81.5% and 71.3% for Hospital for Special Surgery score <70 or infection (95% confidence interval). The cumulative rate of infection after 10 and 18 years was 4.3% and 11.6% based on the life-table survival analysis. The only indication for this type of prosthesis in a primary arthroplasty is a knee with severe deformity, bone loss, or ligament deficiency.