The treatment of bony defects of the tibia at the time of revision total knee replacement is controversial. The place of compacted morsellised bone graft is becoming established, particularly in contained defects. It has previously been shown that the initial stability of impaction-grafted trays in the contained defects is equivalent to that of an uncemented primary knee replacement. However, there is little biomechanical evidence on which to base a decision in the treatment of uncontained defects. We undertook a laboratory-based biomechanical study comparing three methods of graft containment in segmental medial tibial defects and compared them with the use of a modular metal augment to bypass the defect.

Using resin models of the proximal tibia with medial defects representing either 46% or 65% of the medial cortical rim, repair of the defect was accomplished using mesh, cement or a novel bag technique, after which impaction bone grafting was used to fill the contained defects and a tibial component was cemented in place. As a control, a cemented tibial component with modular metal augments was used in identical defects. All specimens were submitted to cyclical mechanical loading, during which cyclical and permanent tray displacement were determined.

The results showed satisfactory stability with all the techniques except the bone bag method. Using metal augments gave the highest initial stability, but obviously lacked any potential for bone restoration.

Retrospective review of 25 patients over 65 years of age with unilateral acetabular fractures managed conservatively showed that seven of the 23 survivors (30%) had an unacceptable functional result. Poor results were associated with: displaced posterior column fractures, osteoporosis, femoral head fracture, delayed diagnosis, inadequate radiographs, inappropriate or too brief traction, and early weight-bearing. In this age group acetabular fractures tend to be low-velocity injuries of osteoporotic bone and are not comparable with those in younger patients.

Using a simple method of quantifying fracture healing, 53 patients who had limb fractures and also severe head injuries were studied; they were compared with 30 patients who had limb fractures but no head injury. Those with head injuries had a greater healing response and united more rapidly. Radiological and histological analysis revealed that the terms "myositis ossificans" and "heterotopic bone" may be more appropriate than "fracture callus" to describe the healing response in these patients.

We report a series of 12 Silastic interposition arthroplasties of the shoulder. There was a very high incidence of dislocation or fragmentation (50%) leading to early failure of the device in seven patients. Our analysis suggests that the operation should be restricted to rheumatoid arthritic shoulders in which there is no loss of bone or distortion of the humeral head.