In this study, DXA scan was employed to evaluate and compare the behaviour of different femoral components including a recently developed stemless implant which features complete stress transfer over the proximal femur.
Average interval between the operation and the DXA exam was 3 years, each group included 20 patients. Bone mineral density was measured by DXA in the seven Gruen femoral regions (ROI), using the software metal removal (Hologic QDR 4500 W, MA-USA).
CFP, IPS and ABG groups showed decreased bone density in ROI I, while Mayo, IPS, ABG and Zweym-ueller were osteopenic in ROI VII. An increased bone density in ROI IV was found in Zweymueller, Mayo, ABG and IPS groups.
Although various treatment options are available, which include shaving, microfractures, abrasion arthroplasty osteochondral allografts and autografts, chondrocyte grafts and unicondylar prostheses, symptomatic articular cartilage defects represent a therapeutic challenge. Since November 2002, as a non-biological answer to the problem, we started using synthetic cartilage implants made of polyvinyl alcohol- hydrogel (PVA – H) (SaluCartilage). This is a transparent synthetic polymer with a molecular weight of 308,000 daltons and 20% of water content, available in cylindrical shape of various diameters. Following the second part of the OATS technique, under arthroscopic control and by mini-arthrotomy, or completely arthroscopically assisted, the cylindrical implant is inserted, using press-fit technique, into previously punched out and dilatated osteochondral defects. Our patients, whose mean age was 56 years (range 48–68 years) have been post-operatively reviewed clinically and by serial MRI exams. Patients showed significant improvement over pre-operative values in the IKDC score, with an average increase of 20 points. Follow-up MRI images revealed a normal healing process, without signs of osteolysis or wear. As complications we had one case of implant dislocation 1 year after surgery and one case of progressive loosening due to osteoarthritic disease, both of which have required a knee prosthesis. Our experience has led us to emphasise the use of this type of treatment only in cases that fullfil precise indications: (a) Third and fourth degree chondral or osteochondral symptomatic defects; (b) focal unicompartmental defects with 15 mm maximum extent; (c) patient’s age limited from fourth to seventh decade of life; and (d) absence of angular deformities or articular instabilities. The synthetic cartilage resurfacing technique has the advantages of no donor defect, one short-step surgical procedure, immediate weight-bearing and no extensive rehabilitation programme. Early results of first 15 patients are being presented, expecting a longer observation follow-up study.