Background
Cartilage is a mechanically highly stressed tissue in the human body and an important part of synovial joints. The joint cartilage is lubricated by synovial fluid with hyaluronic acid (HA) as main component. However, in joints with osteoarthritis HA has a lower concentration and molecular weight compared to healthy joints. In recent years, the intra-articular injection of therapeutic HA lubricant, has become a popular therapy. The effect of HA application on the friction of a complete joint with physiological movement needs to be further determined.
Methods
The aim of the present study was to evaluate the lubrication effect of the joint by three lubricants (NaCl, fetal calf serum (FCS) and HA) and their effect on the friction in nine complete ovine carpo-metacarpal joints. The joints were mounted on a material testing machine and a physiological movement with 10° rotation was simulated with ascending axial load (100 – 400 N). Specimens were tested native, with cartilage damage caused by drying out and relubricated. Dissipated energy (DE) as a measure of friction was recorded and compared.
Results
Investigating the effect of axial load, we found significant differences in DE between all axial load steps (p < .001), however, only for the defect cartilage. Furthermore, we could document an increase in DE from native (Mean: 15.0 mJ/cycle, SD: 8.98) to cartilage damage (M: 74.4 mJ/cycle, SD: 79.02) and a decrease after relubrication to 23.6 mJ/cycle (SD: 18.47). Finally, we compared the DE values for NaCl, FCS and HA. The highest values were detected for NaCl (MNorm = 16.4 mJ/cycle, SD: 19.14). HA achieved the lowest value (MNorm = 4.3 mJ/cycle, SD: 4.31), although the gap to FCS (MNorm = 5.1 mJ/cycle, SD: 7.07) was small.
Conclusions
We were able to elucidate three effects in joints with cartilage damage. First, the friction in damaged joints increases significantly compared to native joints. Second, especially in damaged joints, the friction increases significantly more with increased axial load compared to native or relubricated joints. Third, lubricants can achieve an enormous decrease in friction. Comparing different lubricants, our results indicate the highest decrease in friction for HA.
ZusammenfassungDie penetrierende Kniegelenkverletzung ist ein seltenes Trauma, welches jedoch nicht unterschätzt werden darf. In der Regel besteht die Indikation zur zeitnahen operativen Versorgung. Dieser Fallbericht handelt von einem 17-jährigen Patienten, der durch einen Messerstich eine Knorpelverletzung der lateralen Femurkondyle erlitt. Es folgte die Gelenkspülung mit Bergung des Knorpelflakes und endgültiger Versorgung mittels autologer Chondrozytentransplantation. Die Gewinnung von Knorpelzellen aus dem Flake unterblieb aufgrund des Risikos einer Keimbesiedlung sowie des Qualitätsverlustes der Chondrozyten.
ZusammenfassungIntraartikuläre Osteoidosteome (IAOO) sind mit 10 % aller Osteoidosteome selten. Die atypischen klinischen und radiologischen Befunde führen meist zu einem langen Intervall zwischen Beschwerdebeginn und Diagnosestellung sowie Einleitung einer adäquaten Therapie. Dieser Fallbericht handelt von einer 32-jährigen Patientin, die seit Jahren intermittierende Kniegelenksschmerzen bei tiefer Beugung und selten nachts angibt. Bei IAOO in der Trochlea femoris war eine Radiofrequenzablation (RFA) aufgrund der direkt subchondralen Lage kontraindiziert. Daher erfolgte eine operative Sanierung mittels Knorpel-Knochen-Transplantation.
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