We performed posterior fixation with a Hartshill-Ransford contoured loop in 43 patients with instability at the craniocervical junction. No external bracing was used. Fifteen patients had congenital malformations, ten had tumours, seven had 'bone-softening' conditions (such as osteogenesis imperfecta), five had suffered complicated fractures, three had occipito-C1-C2 hypermobility due to lax ligaments and three had severe degenerative spondylosis with pseudotumours of the transverse ligament. Twenty-nine patients had transoral decompression of the cord before fixation. In most cases, cancellous bone grafts taken from the iliac crest were used to induce fusion; in nine very ill patients, no bone graft was used. In the whole series there was no instance of construct failure, broken wire or laminar fracture. The best results were achieved in patients with tumours or bone-softening conditions. No patient with normal neurology deteriorated after surgery but seven had worse neurological deficits after operation than before. Neck stiffness caused half the patients to change their lifestyle.