[In vivo assessment of mobility of meniscal bearings with ultrasound].
Clinical scores and fluoroscopically guided standard X-rays are still the golden standard for evaluating the outcome of total knee arthroplasty, but up to now there was no way to evaluate the function of mobile inlays except with digital fluoroscopy. We describe a new method using a flat 8-MHz ultrasound for the in vivo measurement of meniscal bearings (MB) with an accuracy and precision of 0.7 mm and 0.4 mm, respectively. In 73 knees with LCS classic total knee replacement, all of the medial (100%) and 71 of the lateral (97%) MB could be analyzed. The MB moved unhindered with an average total shift of 4.5 mm (range: 0.2-12.1) on the medial and 4.2 mm (range: 0.8-13.2) on the lateral side. A significant correlation was found between the active range of motion (ROM) of the knee joint and the medial MB's shift ( p=0.004) but not for the lateral MB ( p=0.114). Three knees had to be revised due to aseptic loosening (2) or excessive PE wear (1). No single parameter of the ultrasound analysis could be detected to be predictive for the MB's failure. Conventional ultrasound allows the analysis of MB function at low cost with an accuracy better than 1 mm. This method is an alternative to radiological methods and suitable for studies with larger numbers of patients followed over longer periods.
Aigner
C
C
Universitätsklinik für Orthopädie, Graz, Austria. christian.aigner@kfunigraz.ac.at
Radl
R
R
Pechmann
M
M
Rehak
P
P
Windhager
R
R
D001172:Arthritis, Rheumatoid / Q000601:surgery*; D019544:Equipment Failure Analysis / Q000706:statistics & numerical data; D005471:Fluoroscopy; D005500:Follow-Up Studies; D006801:Humans; D007720:Knee Prosthesis / Q000706:statistics & numerical data; D008432:Mathematical Computing; D008592:Menisci, Tibial / Q000000981:diagnostic imaging*; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000601:surgery; D011474:Prosthesis Design; D016059:Range of Motion, Articular / Q000502:physiology*; D012086:Reoperation; D015203:Reproducibility of Results; D013977:Tibia / Q000000981:diagnostic imaging; D014463:Ultrasonography
In-vivo-Evaluierung der Meniskallagerbeweglichkeit mittels Ultraschall.