The late outcome of 562 consecutive femoral neck fractures is presented; 396 were treated with a Thompson hemiarthroplasty, 121 by internal fixation, 4 by primary total hip replacement, and 41 were treated conservatively. Mortality during the first 30 days was 5%. The incidence of primary and secondary local complications after osteosynthesis was 25%. Further operations were carried out in 10% of the hemiarthroplasties. Seventyeight patients were evaluated clinically and radiologically lO years after this operation; 24 had been converted to total hip replacements, and in 23 of the remaining 54 the prosthesis appeared loose on radiographs. There was severe protrusion of the metal head in 25 cases. The clinical result was excellent or good in only 17 of 78 cases. We conclude that osteosynthesis or total hip replacement, rather than a Thompson hemiarthroplasty, should be considered for the treatment of femoral neck fractures if the patient is active and appears to have a life expectancy of several years. Rbsum~. Prksentation du devenir ~t long terme de 562fractures consbcutives du col du fbmur: 396 ont btb traitbes par prothdse de Thompson; 121 par os-tbosynthOse; 4 par arthroplastie totale d'emblbe et 41 orthopbdiquement. La mortalitb pendant les 30 premiers jours a ktk de 5%. La frbquence des complications locales, primitives et secondaires, aprds hbmi-arthroplastie de Thompson a btb de 25%. D'autres interventions ont ktb rbalisbes dans 10% des hbmi-arthroplasties. 78 sujets ont btb examinks cliniquement et radiologiquement 10 ans aprds cette opbration; 24 ont bbn~ficib secondairement d'une Offprint requests to: H. Kuokkanen proth~se totale, et 23 des 54 restants pr~sentent d la radio des signes de descellement. II existe une importante protrusion de la t~te mbtallique dans 25 cas. Le rbsultat clinique n'est excellent ou bon que clans 17 de ces 78 cas. Nous en concluons que l'os-tbosynthOse ou l'arthroplastie totale, plut6t que l'hkmi-arthroplastie de Thompson, constituent le traitement des fractures du col du fbmur chaque fois que le malade est actif et semble avoir une espbrance de vie de plusieurs annbes.