[All-polyethylene tibial component in Walter-Motorlet total knee arthroplasty. Long-term outcomes]. / ALL-POlY standardní tibiální komponenta náhrady kolenního kloubu Walter-Motorlet v dlouhodobém hodnocení

PURPOSE OF THE STUDY: An analysis of long-term results of the all-polyethylene tibial component in Walter-Motorlet cemented condylar knee arthroplasty, with a standard tibial plateau (STP) of our own design. MATERIAL AND METHODS: A total of 49 patients underwent knee replacement; of them, 35 (71.4%) with 38 Walter-Motorlet implants using the STP were evaluated. The average age at the time of evaluation was 87.3 years. The follow-up ranged from 18 to 27 years (average, 24.6 years). Mechanical properties of the STP were tested by experimental measurements and in a photoelasticimetric study. The clinical results were evaluated according to the EULAR Knee Assessment Chart (EKACH). Twenty-four patients (26 knees; 49%) had osteoarthritis (OA) and 11 (12 knees; 23%) had rheumatoid arthritis (RA). Of the 14 (28.6%) patients not included in evaluation, seven (14.3%), with seven knees, required revision arthroplasty and seven (14.3%), with 10 knees, were lost to follow-up. RESULTS: Of the 38 implants evaluated by the EKACH at an average of 24.6 years, subjectively, 14 (36.8%) knees were free from pain and 14 (36.8%) were mildly painful. The remaining 10 (26.4%) joints were acutely painful on walking up or down the hill. In 14 (36.8%) cases the patients experienced their knees as stable. Light domestic chores were routinely performed by 17 patients (10 OA and 7 RA; 48.6%). One (2.9%) OA patient had a full-time job, and nine (25.7%) patients were socially independent. The functional outcome was significantly related to the patient's age at the time of evaluation. Complications included STP aseptic loosening in five (13.1%) and late infection in two (5.2%) knees. Radiography showed translucent zones below an all-polyethylene component in 14 (36.8%) knees. DISCUSSION The five cases of aseptic loosening may have been due to insufficient hardness of a U-shaped polyethylene component and long-term stress at the bone-implant interface. In the majority of knees the anterior cruciate ligament was defective or missing completely. Maintenance of the posterior cruciate ligament facilitates absorption of the greater part of forces at the cement-bone interface, as also reported by other authors. The high incidence of complications associated with patellar components, as described in the literature of the late 1970s and the early 1980s, led us to avoid the primary use of a patellar implant. CONCLUSIONS: Our evaluation showed that, in 73% of the cases, the all-polyethylene tibial component was a suitable and inexpensive implant with very good or good long-term results on average at 24.6 years of follow-up. Since the quality of currently produced polyethylene is high, we recommend the use of all-polyethylene tibial components in all indicated cases.

Treatment of orthopedic infections caused by resistant staphylococci.

During 1999-2005 we treated 15 patients with linezolid for relevant infections of locomotion apparatus (7 cases with endoprosthesis infection, 5x osteomyelitis and 3x another infection). With the exception of one case the antibiotic therapy was always combined with appropriate surgical intervention. Average period of linezolid administration was 26 d; linezolid was applied from the beginning intravenously on average for 10 d, and then orally for 16 d (average). There were no undesirable effects in the file. Success rate reached 86.6%. MRSA strains were proved by standard methods: growth on Mueller-Hinton agar with increased concentration of NaCl and 2 mg/L of oxacilline, and measuring inhibitory zones around cephoxitine disk. The sensitivity to other antibiotics was specified by disk-diffusion test; that to linezolid was verified by E-test. Linezolid represents a medical reserve for the treatment of multiresistant Gram-positive infections or for emergencies, when allergy onset, high toxicity risk, intolerance, etc. do not allow to use other, in vitro effective, antibiotics.