Polyethylene wear particles do not induce inflammation or gelatinase (MMP-2 and MMP-9) activity in fibrous tissue interfaces of loosening total hip arthroplasties.

In vitro and in vivo studies have suggested that polyethylene wear particles are the main cause for osteolysis in prosthetic loosening. Elevated amounts of proteases including gelatinases (or matrix metalloproteinases MMP-2 and MMP-9) have been found in fibrous tissue interfaces of loosened total hip arthroplasties suggesting that proteolysis plays a role in osteolysis. The presence of proteases does not mean that they are active, because activity of proteases is highly regulated at the post-translational level.

Is the long-term outcome of cemented THA jeopardized by patients being overweight?

Although the effect of being overweight on the long- and short-term outcome of THA remains unclear, the majority of orthopaedic surgeons believe being overweight negatively influences the longevity of a hip implant. We asked whether complications and long-term survival of cemented THA differed in overweight patients (body mass index [BMI] > 25 kg/m2) and obese patients (BMI > 30 kg/m2) compared with normal-weight patients (BMI < 25 kg/m2). We retrospectively analyzed 411 consecutive patients (489 THAs) treated with cemented THA between 1974 and 1993.