5-YEAR FOLLOW-UP EVALUATION OF THE NONCEMENTED PRESS-FIT TITANIUM HIP-JOINT ENDOPROSTHESIS

ties with a titanium alloy stem and fixation by the Zweymuller press-fit and an Endler polyethylene threaded cup was reviewed in detail. The minimum follow-up period was 48 months and the maximum 72 months, with an average of 60 months. A scale from zero to five points was applied to evaluate pain, mobility, and motion for a total possible accumulation of 15 points. The global results of the different ethiologic groups (arthrosis, femoral head necrosis, rheumatoid arthritis, and subcapital hip fractures) have been very good and good (12-15 points) in 67.5% of the cases and fairly good and bad in 32.3%. These results have been better in femoral head necrosis than in arthrosis or rheumatoid arthritis, but not as good in subcapital hip fractures. The age groups below 60 had better results than the above 60 groups. The Singh index higher than 3 was correlated with better-than-average results. The polyethylene cup migrated horizontally (more than 4 mm) in 7.6% of the cases and vertically (more than 5 mm) in 10%. The nonevolutionary cortical remodelation of the femur does not influence the results. Prosthetic stem sinking less than 4 mm has been found in 62% of the cases, from 4 to 9 mm in 21%, and greater than 9 mm in 6%. No alterations with clinical consequences attributable to stress-shielding have been detected.