Stephen G. Manifold and Giles R. Scuderi

1. Unicompartmental lateral knee osteoarthritis

2. Age less than 50 years old

3. High-activity level (heavy laborers)

4. Valgus deformity 15 degrees or less

5. Flexion arc greater than 90 degrees

1. Rheumatoid or inflammatory arthritides

2. Tibiofemoral subluxation (medial) greater than 1 cm

1. Knee radiographs including anteroposterior, lateral, sunrise, and standing three-joint films

1. Supine position on a radiolucent operating table with a small padded bolster under the ipsilateral buttock

2. Surgery can be performed with general, epidural, or long-acting spinal anesthesia.

3. Use basic orthopedic instrumentation.

4. Use 1/8-in Steinmann pins, sharp straight osteotomes, and a sagittal saw.

5. Consider variable angle proximal tibia cutting guides to make accurate osteotomy cuts.

6. A 90-degree blade plate should be available for fixation of the osteotomy site.

7. Use fluoroscopic image intensifier for intraoperative imaging.

1. Insertion of the 90-degree blade plate-seating chisel should be performed prior to the osteotomy of the distal femur.

2. For patients without contraindications (i.e., significant peripheral vascular disease), a tourniquet should be placed as proximal as possible on the thigh to avoid minimizing the surgical exposure.

3. Intravenous antibiotics should be administered prior to inflation of the tourniquet.

4. A vertical skin incision is preferred in order to improve exposure for internal fixation and to facilitate possible total knee arthroplasty in the future.

5. The Steinmann pins should be positioned parallel in the lateral plane to avoid rotational problems after the osteotomy.