1. A series of 226 upper tibial osteotomies is reviewed with special reference to the complications occurring in each of the six different operative techniques that have been used.

2 Wedge osteotomy above the tuberosity is the safest operation, but care must be taken to avoid a fracture into the joint.

3. Wedge osteotomy through the lowest part of the tuberosity may be indicated in the presence of large subarticular cysts or collapse of a tibial condyle.

4. The significance of weakness of dorsiflexion of the foot and the dangers of injury to the anterior tibial artery in osteotomies below the tuberosity are discussed.

1. If osteoarthritis of the knee is confined mainly to one tibio-femoral compartment and the range of flexion is 90 degrees or more it can be treated safely and reliably by proximal tibial osteotomy.

2. The operation relieves pain in a large proportion of cases while retaining a useful range of knee flexion.

We are grateful to Miss H. M. Briggs, Research Secretary at Harlow Wood Orthopaedic Hospital, for secretarial assistance.

1. The results are presented of upper tibial osteotomy carried out in ten patients for osteoarthritis of the knee associated with lateral deformity.

2. The operation is indicated when there is severe pain, valgus or varus deformity, and a range of flexion of at least 90 degrees.

3. In every case pain has been relieved, and recovery of movement after operation has been easy.

Conclusions based on forty-six osteotomies show this to be a sound pain-relieving operation for osteoarthritis of the hip. The field of operation has been widened and some of the disadvantages have been avoided by nail and plate fixation. Early results from this method are similar to those from osteotomy and immobilisation in plaster, and it seems likely that the relief of pain will be just as enduring.