Arthritis of the inside, or medial aspect, of the knee is the most common form of degenerative arthritis. It can be caused by an injury, ones genes, or possibly due to being bowlegged. Genu varus, a condition where the alignment of the leg passes through the medial compartment rather than the center of the joint, can result in added contact stresses on the medial compartment of the knee and possibly lead to accerlerated wear of damaged articular cartilage. In certain cases, surgical intervention may be required to slow this degenerative process. A proximal tibial opening wedge osteotomy is one of the procedures presently used by orthopaedic surgeons to correct this condition.
Diagnoses of medial compartment genu varus allignment of the knee can be accomplished by radiographic imaging. Weight bearing x-rays of the knee itsesf and the whole extremity to include the hip, knee, and ankle joints help to assess for the amount of medial compartment arthritis and the amount of genu varus (bowleggedness). The mechanical axis of the leg is evaluated by drawing a line from the center of the femoral head (hip) down to the center of the talus (ankle). This line should pass through the center of the knee. Genu varus alignment is present when the line passes to the inside (medial) aspect of the center of the tibia, while genu valgus alignment is when it passes laterally. The ideal candidate for a proximal tibial osteotomy is a patient of normal weight who has only early osteoarthritic changes, no or a minimal flexion contracture, an arc of motion of the knee at least 100 degrees, a low adductor moment, and no severe osseous defects or intra-articular bone spurs, (osteophytes). A relative contraindication to a proximal tibial osteotomy is the absence of at least one of the just mentioned parameters. Exceptions can be made to the indications, but they are usually due to a patients young age or other factors.
With the use of fluoroscopic guidance, a surgical fracture is made on the medial side of the proximal tibia. Once the fracture is made, a wedge is used to open the fracture site and allow for a plate and screws to be inserted into the tibia to hold the opening apart. After fixation of the plate and screws, allograft bone graft is placed in the area of the opening wedge.
Q1. How long is the recovery period for this procedure?
A1. Patients are usually non weight bearing for 2 months. If x-rays show early healing, some patients are allowed partial weight bearing with crutches at 1 month postop. Then if their x-rays are acceptable, patients are allowed to wean off crutches.
Q2. Will I need to wear a cast after this operation?
A2. No; patients are given an immobilizer for the first two months.
Q3. Will I need to be hospitalized after the operation?
A3. Yes; this is done for pain control and is usually 2 days.
Q4. How likely is this procedure going to relieve my pain?
A4. This procedure is 80-90% successful at 5 years and 70-80% successful at 10 years.
Q5. Will I need to take time off work after this surgery?
A5. Patients will need to take time off work. This is done for pain relief. Patients are usually allowed to return to work in a light duty position at 4 weeks. Manual labor workers are not allowed to work for 4 to 6 months.
Q6. Will the hardware installed ever need to be removed?
A6. Only if the hardware causes irritation will it be removed. If this is the case, we must wait one year from the surgery date to remove the hardware.
Q7. Will I need physical therapy; if so, for how long?
A7. Yes; for the first 2 months range of motion and quad function is worked on. Then a strengtening program is started at 2 months.
Q8. Do I need to take any medications after the surgery?
A8. Yes; patients need to take enteric coated aspirin for 8 weeks to decrease chances of developing deep venous thrombosis (DVT's or blood clots).