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PubMed1996

Infection of a total knee joint prosthesis by peptostreptococcus micros and propionibacterium acnes in an elderly RA patient: implant salvage with longterm antibiotics and needle aspiration/irrigation.

We describe the favourable long-term outcome after late total knee joint prosthesis infection in an elderly RA patient. Peptostreptococcus micros and Propionibacterium acnes were cultured from the synovial fluid, and the finding of a coexistent abscess at the root of a wisdom tooth suggested a dental origin to the joint infection. Long-term antibiotics in conjunction with aspiration/irrigation resulted in salvage of the implant and an excellent functional outcome.

Aged↗
PubMed2004

Comparison of anterior-posterior-glide and rotating-platform low contact stress mobile-bearing total knee arthroplasties.

BACKGROUND: The anterior-posterior-glide Low Contact Stress mobile-bearing knee prosthesis was developed to approximate the natural kinematics of the knee more closely than the rotating-platform Low Contact Stress mobile-bearing knee prosthesis does. The purpose of the present study was to compare the results associated with these two prostheses in patients managed with simultaneous bilateral total knee replacement. METHODS: One hundred and ninety patients received an anterior-posterior-glide Low Contact Stress mobile-bearing prosthesis in one knee and a rotating-platform Low Contact Stress mobile-bearing prosthesis in the contralateral knee. The mean age of the patients at the time of the index procedure was sixty-four years. Eleven patients were men, and 179 patients were women. The mean duration of follow-up was 6.4 years (range, five to seven years). The patients were followed clinically and radiographically with use of the knee-rating systems of the Knee Society and the Hospital for Special Surgery. RESULTS: The mean postoperative Hospital for Special Surgery knee score was 89.4 points for the knees treated with the anterior-posterior-glide mobile-bearing prosthesis and 88.6 points for those treated with the rotating-platform mobile-bearing prosthesis. Three knees in each group had a poor result. Two knees in each group had persistent moderate pain. One knee with an anterior-posterior-glide prosthesis had permanent tibial and deep peroneal nerve palsies, and one knee with a rotating-platform prosthesis had a permanent deep peroneal nerve palsy. No knee had aseptic loosening, revision, measurable wear of the tibial or patellar polyethylene bearing, or osteolysis. CONCLUSIONS: After a minimum duration of follow-up of five years, the results associated with the anterior-posterior-glide and rotating-platform Low Contact Stress mobile-bearing total knee replacements were favorable and comparable.

Arthroplasty, Replacement, Knee↗
PubMed2005

Increased muscle activity to stabilise mobile bearing knees in patients with rheumatoid arthritis.

The aim of this study was to assess the differences in muscle activity (surface EMG) between a posterior stabilised (PS) total knee design and a mobile bearing (MB) posterior cruciate ligament retaining design in rheumatoid arthritis (RA) patients during a step-up task. Four patients with a PS total knee prosthesis and three patients with a MB total knee prosthesis were selected based on pain score, knee function, range of motion and joint stability. Clinical scores and functional scores were comparable between the two groups pre-operatively and at the 1-year follow-up. Visual analysis of the EMG activity of the main flexor and extensor muscles showed that the activity of both extensor and flexor muscles of the MB group was on average higher compared to the PS group. When the maximum activities of the muscles were compared, the patients in the MB group showed a significant higher maximum peak activity (p<0.05) of the Vastus Medialis (VM), Vastus Lateralis (VL) and Semitendinosus (ST) during step-up than the patients in the PS group. Also the instance of activation of the Vastus Medialis and the Vastus Lateralis was significant earlier in the MB group compared to the PS group. Since the differences between the PS and the MB group did not only show an increase of muscle activity but also an earlier activation of the flexor muscles, this may express compensation by coordination. Rehabilitation programs for RA patients should include besides muscle strength training, elements of muscle-coordination training.

Aged↗
PubMed2000

Revision surgery after failed unicompartmental knee arthroplasty: a study of 35 cases.

This retrospective study evaluates the results of 35 revision procedures after failed unicompartmental knee arthroplasty (UKA) in 34 patients, which were done during the period 1986 to 1996. There were 28 women and 6 men with a mean age of 71 years (range, 54-85 years). In all cases, St. Georg and Endo (W. Link, Hamburg, Germany) unicompartmental prostheses were used except 1 PCA unicondylar implant (How medica, Rutherford, NJ) and 1 Böhler unicondylar implant (Allo Pro, Baar, Switzerland). Failures most frequently were due to aseptic loosening followed by polyethylene wear. Two deep infections occurred. Revisions were performed 1 week to 11 years after UKA; 23 were required within the first 5 years. In most cases, revision was to a total knee arthroplasty. Partial component exchange was done in 9 cases. All 34 patients were evaluated clinically after exchange arthroplasty. After a mean follow-up time of 4 years (range, 1-12.2 years), we found 11 excellent, 13 good, 4 fair, and 7 poor results according to the Hospital for Special Surgery score. The fair and poor results were due to aseptic loosening of the knee prosthesis in 6 knees. One of 2 patients with deep infection needed femoral amputation. With correct indication and considerable surgical experience, UKA is still a good alternative, especially in the elderly patient.

Aged↗
PubMed1989

Serum creatine kinase-B activity in patients with chronic lower-limb ischemia and after leg amputation.

Serum creatine kinase-B (CK-B) activity was measured and electrocardiograms (ECG) recorded before and after operation in two groups of ten orthopedic patients. Group I underwent lower-limb amputation because of severe, chronic ischemia of the leg and group II (controls) had knee prosthesis implantation or knee ligament surgery. In group I the number of patients with CK-B activities exceeding the discrimination value (0.25 muka-tal/l) for acute myocardial infarction preoperatively and 2, 24, 48, 72 hours, and at 7 days postoperatively were, respectively, three, three, five, three, two and nil. In Group II the serum CK-B activity remained below the myocardial infarction discrimination value in all patients at all times. No ECG abnormalities indicating myocardial infarction appeared in any patient of either group. The study indicates that severe, chronic lower-limb ischemia and amputation of the leg may cause elevation of non-cardiac CK-B activity in serum that can interfere with enzymatic recognition of acute myocardial infarction.

Adult↗
PubMed2005

[Diagnosis specific differences in knee joint geometry. A challenge for the correct axial implantation of long stems in total knee arthroplasty].

BACKGROUND: Arthrotic deformities with changes in knee geometry can produce difficulties in implanting long stem knee prosthesis systems using intramedullary alignment. They can result in incorrect lower limb axis and prosthesis positioning. The aim of the presented study was to measure knee geometry in patients with varus and valgus gonarthrosis in order to define diagnosis related differences. METHODS: A total of 75 patients with indication for total knee arthroplasty were divided in two groups using the weight bearing lower limb axis: patients with varus gonarthrosis (n=43) and with valgus gonarthrosis (n=32). Angles and extensions, important for knee prosthesis implantation, were measured, digitalized and analyzed. The results were investigated for diagnosis specific differences. RESULTS: After regulation of the measured extension in mean femur/tibia lengths, significant diagnosis specific differences were found: femur condyles were widened towards pathologic weight bearing (P<0.044), and the mechanical tibia axis of the varus gonarthrosis group is transferred to the lateral side (P<0.046) and in projection over the lateral internal cortical substance. CONCLUSION: The significant differences in deformed arthrotic knees indicate that for an optimal postoperative result the use of standard implants is not always sufficient. Modular knee prosthesis systems can provide adequately for individual demands.

Adult↗
PubMed1992

Fibrosarcoma in association with a total knee joint prosthesis.

A case of fibrosarcoma of the proximal tibia, arising at the site of a cemented Richards total knee joint replacement with cobalt chrome alloy is reported. The patient, an 80-year-old man, received the endoprosthesis because of osteoarthritis of the knee 4 years ago. The literature on malignant tumours occurring in association with endoprostheses is summarized and briefly discussed.

Aged↗
PubMed2000

[What retropatellar changes result by implantation of a superficial knee joint prosthesis?].

The aim of this study was to evaluate the retropatellar pressure, force, and contact area in cases of knee arthroplasty compared to knees without arthroplasty. We examined six leg specimens before and after knee arthroplasty. The modified Thiel fixation was used, and arthroplasty was the Genesis I without patellar implant (Fa. Smith & Nephew, Schenefeld). Contact measurements were performed with pressure-sensitive film (Fuji Prescale type "super low") in 45 degrees, 60 degrees, 90 degrees, and 120 degrees knee flexion. The results were evaluated with special software, "Pressure Imaging and Analyzing System FPD-901 Series". The leg was exarticulated in the hip joint and the knee joint was opened from a suprapatellar approach. The film was placed at a defined area between the facies patellaris of the femur and facies articularis of the patella. Instantaneous pressure was measured during a time of 5-s pressure increase and a further 5 s. A force of 280 N was applied to the quadriceps muscle. Before knee arthroplasty, the contact area measured 154.3 mm2, the average pressure was 1.14 MPa, the force 182.13 N. After knee arthroplasty, the contact area was 119.94 mm2, the average pressure 1.522 MPa, the force 180.98 N. Following knee arthroplasty the contact area decreased significantly (P = 0.015), and the average (P = 0.0001) and maximum pressure (P = 0.0003) increased significantly. The force did not change significantly (P = 0.7642). The choice of the knee arthroplasty implant and approach to the knee joint should be considered in order to achieve an increased retropatellar contact area thus preventing smaller contact areas than before knee arthroplasty. The increased contact area could also prevent increasing retropatellar pressures after knee arthroplasty and further complications.

Aged↗
PubMed2004

Prosthetic replacement of the medial meniscus in cadaveric knees: does the prosthesis mimic the functional behavior of the native meniscus?

UNLABELLED: Meniscus replacement by a polymer meniscus prosthesis in dogs resulted in generation of new meniscal tissue. HYPOTHESIS: Optimal functioning of the prosthesis would involve realistic deformation and motion patterns of the prosthesis during knee joint motion. STUDY DESIGN: Controlled laboratory study. METHODS: The movements of the meniscus were determined during knee joint flexion and extension with and without internal and external tibial torque by means of roentgen stereophotogrammetric analysis. Subsequently, the meniscus in 6 human cadaveric knee joints was replaced by a meniscus prosthesis. RESULTS: All different parts of the meniscus showed a posterior displacement during knee joint flexion. The anterior horn was more mobile than the posterior horn. The prosthesis mimicked the movements of the meniscus. However, the excursions of the prosthesis on the tibial plateau were less. The knee joint laxity was not significantly higher after replacement with the meniscus prosthesis. CONCLUSIONS: The prosthesis approximated the behavior of the native meniscus. Improvement in both the gliding characteristics of the prosthetic material and the fixation of the prosthesis may improve the function. CLINICAL RELEVANCE: The meniscus prosthesis needs to be optimized to achieve a better initial function in the knee joint.

Aged↗
PubMed1993

Oral rifampin plus ofloxacin for treatment of Staphylococcus-infected orthopedic implants.

We examined the effectiveness and safety of the combination of rifampin plus ofloxacin given orally for treating prosthetic orthopedic implants infected with staphylococci. The prospective cohort study was conducted in a referral public hospital with ambulatory care services between 1985 and 1991. Consecutive patients from whom Staphylococcus organisms susceptible to the study drugs were isolated from their orthopedic implants and who had no contraindication to the treatment were eligible for the study. All patients were treated orally with rifampin, 900 mg/day, plus ofloxacin, 600 mg/day. Patients with hip prosthesis infection were treated for 6 months, with removal of any unstable prostheses after 5 months of treatment; patients with knee prosthesis infection were treated for 9 months, with removal of the prosthesis after 6 months of treatment; and patients with infected bone plates were treated for 6 months, with removal of the plate after 3 months of treatment, if necessary. Monthly clinical evaluations were conducted until the completion of the treatment and follow-up or telephone interviews were conducted at 6, 12, 24, 36, 48, and 60 months thereafter. Treatment failures were documented by clinical evaluation, sampling of the infected site for culture and antibiotic activity measurement, and fistulography, if possible. Cure was defined as the absence of clinical, biological, and radiological evidence of infection 6 months after the completion of treatment, treatment failure was defined as the absence of cure, and relapse was defined as the reappearance of infection caused by the same Staphylococcus isolate that caused the original infection, regardless of the timing of this secondary infection. Among 51 patients included in the study and evaluable for safety, 4 patients had side effects and were not evaluable for treatment effectiveness; the overall success rate was 74% among 47 patients, with a success rate of 81% for the hip prosthesis group, 69% for the knee prosthesis group, and 69% for the osteosynthesis device group. Eight treatment failures were relaxed to the isolation of a resistant bacterium. The combination of rifampin administered orally plus ofloxacin is a suitable alternative to the conventional long-term intravenous therapy for treatment of orthopedic implants infected with staphylococci.

Administration, Oral↗
PubMed1991

[2- to 5-year follow-up of cementless implantable knee joint prosthesis of the Miller-Galante type].

Based on a prospective study protocol, the two- to five-year results of the Miller-Galante cementless total knee arthroplasty are presented. Sixty-four implants were placed in 59 patients: 60 implantations were cementless and 4 cemented. Clinically, the scores for pain, range of motion, walking and stair climbing improved significantly. Radiographically, the uncemented components displayed no signs of definite or possible loosening, whereas one of the cemented components was found to be definitely loose. On histological evaluation of the retrieved implants, all components had bone ingrowth.

Aged↗
PubMed1978

The mechanics of the knee and prosthesis design.

The mechanisms controlling and limiting movement and serving to transmit load between the femur and the tibia are discussed. Having accounted for the transmission of all components of force and couple across the joint and noted the load-bearing role of the menisci, some principles which might guide the design of knee prostheses are deduced. It is shown that current designs transgress some of these principles. An experimental prosthesis is then described, which incorporates analogues of the natural menisci. The possible practical application of this novel principle has been studied in cadaveric human joints and in living patients.

Biomechanical Phenomena↗
PubMed2000

[Therapy of bacterial knee joint infection by radical synovectomy and implantation of a cemented stabilized knee joint endoprosthesis].

INTRODUCTION: The report presents an alternative to the treatment of joint destruction in cases of knee joint empyema by resection or arthrodesis: implantation of a stabilised knee prosthesis using antibiotic-loaded bone cement for fixation. METHOD: From 1985 to 1997 a total of 33 knees in 32 patients (21 female, 12 male) were treated for knee empyema by radical synovectomy and implantation of a stabilised knee prosthesis fixed in position with antibiotic-loaded bone cement. The antibiotics were chosen according to the antibiogram of the pathogen. In all these cases the infections had not responded to previous treatment. The criterion for success was the elimination of infection. The follow-up period ranged from 2 to 15 years. RESULTS: Of 33 infected knees 31 (93.9%) were followed up. In 22 cases (71.0%) the infection was eliminated by primary surgery. In five cases (16.1%) further exchange operations were necessary to eliminate the infection. In four cases (12.9%) preservation of the joint was not possible. CONCLUSION: Uncontrolled infection in cases of knee empyema and destruction of the joint can be treated by radical synovectomy and implantation of a stabilised knee prosthesis using antibiotic-loaded bone cement for fixation. The success rate corresponds to the results of one-stage exchange arthroplasty to treat periprosthetic infection of knee prostheses. This therapy should be performed only in specialised centres which have the facilities and personnel essential for accurate bacteriological diagnosis and recommendation.

Adult↗