We have developed a new tensor for total knee replacements which is designed to assist with soft-tissue balancing throughout the full range of movement with a reduced patellofemoral joint. Using this tensor in 40 patients with osteoarthritis we compared the intra-operative joint gap in cruciate-retaining and posterior-stabilised total knee replacements at 0°, 10°, 45°, 90° and 135° of flexion, with the patella both everted and reduced.

While the measurement of the joint gap with a reduced patella in posterior-stabilised knees increased from extension to flexion, it remained constant for cruciate-retaining joints throughout a full range of movement. The joint gaps at deep knee flexion were significantly smaller for both types of prosthetic knee when the patellofemoral joint was reduced (p < 0.05).

The tension of a repaired rotator cuff was evaluated in nineteen patients who had a repair of a full thickness rotator cuff tear. The tension of the repaired cuff was measured at the operation using a simple spring scale. The tension was evaluated regarding the size of the tear, the duration of the symptom, the presence of trauma, and the post-operative results using a UCLA score. The average of the tension at the arm in 0, 30, and 60 degree elevations were 39.2±18.4N, 23.5±17.2N, and 14.2±13.4N respectively. The average tension of the patient who suffered from a trauma was 20.3±15.8N, whereas the one in the patients who had no history of trauma was 35.0 ±18.0N. The slight positive relation, not statistically significant, was found between the tension and the size of the tear. We could not find a significant relation between the tension and the range of motion or the muscle power in this study. The UCLA score was significantly higher in those patients who had less tension of a repaired rotator cuff. We have to be careful not to put too much tension on the rotator cuff when we repair it. Too much tension might damage the muscles and musclotendious units of the rotator cuff or fail to unite the cuff to the bone, resulting in dysfunction of the rotator cuff postoperatively. Then, how much is "too much"? Only a few papers have described the details of the tension of a repaired cuff. Our results show that the lower the UCLA score in patients with a higher tension of the repaired cuff. These results suggest that the tension of the repaired cuff, indeed, changes the results of a rotator cuff repair.

We treated 75 patients with benign bone tumours by curettage and filling the defect with calcium hydroxyapatite (HA). There were 28 women and 47 men with a mean age of 27.7 years (3 to 80). The mean follow-up was for 41.3 months. Postoperative radiological assessment revealed that the implanted HA was well incorporated into the surrounding host bone in all patients. Two patients suffered fractures in the postoperative period. Two patients complained of pain associated with HA in the soft tissues, but this diminished within six months. No patient had local pain at the final follow-up. Recurrence of the tumour was seen in three cases. Histopathological study of the implanted area showed removal of the HA by histiocytes and multinucleated giant cells, and the formation of much appositional bone. We conclude that HA is an excellent bone-graft substitute in surgery for benign bone tumours.

We studied the precise role of the fracture haematoma in healing by the experimental transplantation of the haematoma at two days and four days after fracture of the rat femur to subperiosteal and intramuscular sites. We used bone marrow and peripheral blood haematomas for control experiments. The transplanted two-day fracture haematoma produced new bone by endochondral ossification at the subperiosteal site, but not at the intramuscular site. Four-day fracture haematoma produced new bone formation at both subperiosteal and intramuscular sites. These results suggest that fracture haematoma has an inherent osteogenetic potential.