Niinimäki T J, Ruuskanen M M, Jalovaara P K
Department of Surgery, University Hospital, SF-90220, Oulu, Finland.
Eur J Orthop Surg Traumatol. 1995 Dec;5(2):113-8. doi: 10.1007/BF02716252.
From 1983 to 1985, we performed 105 primary hip replacements in 92 osteoarthritic patients, using a non-cemented uncoated RM polyethylene cup. After a follow-up of 8.2 (7.0-9.0) years, 12 patients had died, five sockets had been revised for loosening and three for dislocation, three patients had been lost to follow-up, and three had been excluded due to severe general illnesses.The remaining 66 patients with 79 hip replacements were reviewed clinically and by radiography, which showed osteolytic foci, mean size 13×18 mm, around 17 acetabular sockets mostly around the superior dome of the cup. Osteolytic foci were also seen around 10 femoral stems, and they were significantly more frequent in the 12 cases, where the socket had migrated.After an exclusion of 11 patients due to a loose stem (one revised) and eight for other illnesses, an excellent or good overall functional outcome was seen in 51% of the remaining 61 hips, a fair outcome in 20% and a poor outcome in 29%. The influence of acetabular pathology on pain and function seemed to be slight.The non-cemented uncoated polyethylene socket involves over time, a high rate of osteolysis and migration, which also endangers the fixation of the stem. These phenomena do not necessarily give symptoms. Regular radiographic reviews are therefore essential. The socket should be exchanged if the stem is revised.
