ABSTRACT
An experimental study was conducted to determine whether low-intensity pulsed ultrasound stimulation (LIPUS), extracorporeal shockwave treatment (ESWT) and radial pressure wave treatment (RPWT) modulate Akt, bone morphogenetic protein-2 (BMP-2), extracellular signal-regulated kinase-2 (ERK-2), focal adhesion kinase (FAK) and transforming growth factor-ß1 (TGF-ß1) during bone healing in rat tibial defects. Rat tibial defects were exposed to 500 shots of ESWT delivered at 0.12 mJ/mm2, 500 impulses of RPWT operated at 2.0 bar or to daily 20-min 30 mW/cm2 LIPUS. Following 1, 3 and 6 wk, bones were harvested to determine the expression and activity of Akt, BMP-2, ERK-2, FAK and TGF-ß1. Animals exposed to ultrasound were followed up to 3 wk. Protein expression and activity were unchanged following LIPUS treatment. ESWT increased Akt activity 2.11-fold (pâ¯=â¯0.043) and TGF-ß1 expression 9.11-fold (pâ¯=â¯0.016) at 1 wk and increased FAK activity 2.16-fold (pâ¯=â¯0.047) at 3 wk. RPWT increased FAK activity 2.6-fold (pâ¯=â¯0.028) at 3 wk and decreased Akt expression 0.52-fold (pâ¯=â¯0.05) at 6 wk. In conclusion, the protocols employed for ESWT and RPWT modulated distinct signaling pathways during fracture healing, while LIPUS standard protocol did not change the usual signaling pathways of the proteins investigated. Future studies are required to monitor osteogenesis so that the biologic meaning of our results can be clarified.
Subject(s)
Bone Morphogenetic Protein 2/metabolism , Focal Adhesion Protein-Tyrosine Kinases/metabolism , Mitogen-Activated Protein Kinase 1/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Tibia/metabolism , Transforming Growth Factor beta2/metabolism , Ultrasonic Therapy/methods , Animals , Disease Models, Animal , Extracorporeal Shockwave Therapy/methods , High-Energy Shock Waves , Immunoblotting , Male , Rats , Tibia/injuries , Ultrasonic Waves , Wound Healing/physiologyABSTRACT
Metallosis is an uncommon complication following total knee arthroplasty that leads to osteolysis and implant loosening due to chronic inflammatory reaction. Abrasion between the metallic surfaces of the implant releases metallic debris that interacts with the periprosthetic soft tissues and causes chronic synovitis. Here we present a case of a 65-year-old man who had undergone total knee arthroplasty 10 years ago and developed implant loosening associated with severe metallosis and varus instability. Radiographs show the three typical signs of metallosis: metal-line sign, bubble sign, and cloud sign. This patient was subjected to revision surgery consisting of debridement and primary implant replacement by a hinged endoprosthesis. Knowledge of the typical radiographic and clinical findings of metallosis is important to rapidly diagnose this complication and avoid progressive joint destruction.
