Measuring the pressure pattern of the joint surface in the uninjured knee.
OBJECTIVE
Testing an applicable intraoperative system for measuring surface pressure in knee joints, simulating as accurately as possible operating theatre conditions.


METHODS
Cadaver study.


METHODS
Pressure probes were introduced into the knee joints medially and laterally (K 6900 quad probes) in five cadavers, providing real-time data with computerized data recording (K-scan system, manuf. Tekscan Inc., South Boston, MA). The initial position of the knee was flexed and hanging, as in a leg holder. In simulation of usual operating theatre procedures, the knee was manually extended to 0 degrees and again brought to hanging position. The data are given as relative-pressure values and should serve as the basis for intraoperative use. During arthroscopy, absolute-pressure values would then be influenced by the pressure of the arthroscopy pump.


RESULTS
In 90 degrees flexion the average pressure ratio between the medial and lateral joint compartments was initially 1:1.5. When the leg was brought to full extension the pressure in the medial compartment increased, giving a pressure ratio of 1:1 at about 15 degrees and 1.8:1 at full extension. When bringing the leg back again to 90 degrees a similar pressure ratio curve was recorded.


CONCLUSIONS
The pressure relationship between the medial and lateral knee compartments could be recorded and was found reproducible in simulated operating-theatre conditions. The measurement of joint surface pressure during implantation of an anterior cruciate ligament graft could provide data for individual intraoperative quality control, thus improving surgical results.
Kdolsky
Richard K
RK
Department of Traumatology, University of Vienna Medical School, Vienna, Austria. richard.kdolsky@akh-wien.ac.at
Al Arabid
Basil
B
Fuchs
Martin
M
Schabus
Rudolf
R
Vécsei
Vilmos
V
D000328:Adult; D002102:Cadaver; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation*; D019651:Plastic Surgery Procedures / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014160:Transducers, Pressure