We report the five- to-ten year results of Anderson Orthopaedic Research Institute type-2 bone defects treated with modular metal augments in revision knee surgery. A total of 102 revision knee arthroplasties in patients with type-2 defects treated with augments and stems were prospectively studied. Seven patients (seven knees) had incomplete follow-up and 15 patients (16 knees) died with the arthroplasty We recommend the use of modular augmentation devices to treat type-2 defects in revision knee surgery.
1. Thirty-seven cases of fracture of the dens have been studied. 2. The incidence of non-union was high: 64 per cent after apparently adequate closed treatment. 3. Possible causes of the high incidence of non-union have been studied : attention is drawn to the effect of displacement and to that of posterior displacement in particular. 4. Non-union of the dens with potential instability at the atlanto-axial joint is not acceptable in a patient who expects to lead a normal active life. 5. Atlanto-axial fusion is the method of choice in the treatment of instability ; once that has been secured, pseudarthrosis of the dens is no longer significant.