J Korean Orthop Assoc.  2010 Jun;45(3):204-209. 10.4055/jkoa.2010.45.3.204.

Total Knee Arthroplasty Using an Intra-Articular Correction Method in Patients with Extra-Articular Deformity of the Femur

• Bae DK
• Song SJ
• Yoon KH
• Noh JH
• Lee SM

• KMID: 2185519
• DOI: http://doi.org/10.4055/jkoa.2010.45.3.204

Abstract

PURPOSE
To investigate the result of total knee arthroplasty (TKA) using an intra-articular correction in patients with extra-articular deformity of the femur. MATERIALS AND
METHODS
We performed 23 TKAs in 23 patients with extra-articular deformity of the femur. The mean age was 58.0 years and the follow-up period averaged 54.7 months. The American Knee Society's knee and function score were evaluated, and the mechanical axis (MA) was measured. Sixteen knees with a deformity in the distal third of the femur were assigned to group I and 7 knees with a deformity in the proximal or middle third were assigned to group II. Between groups differences in results were analyzed.
RESULTS
The average knee score was 47.8 preoperatively and 91.6 at the last follow-up. The average function score was 46.9 preoperatively and 89.1 at the last follow-up. The MA averaged varus was 7.7degrees preoperatively and 1.0degrees postoperatively. The average knee score at the last follow-up was 90.1 in group I and 95.0 in group II. The average function score at the last follow-up was 87.8 in group I and 92.1 in group II. The MA averaged varus was 2.0degrees in group I and 1.3degrees in group II (p=0.042).
CONCLUSION
TKA in conjunction with intra-articular correction produced satisfactory results for patients with an extra-articular deformity of femur. The possibility of incomplete correction of limb alignment should be carefully considered, especially in cases with a severe deformity at the distal third of the femur.

Keyword

femur; extra-articular deformity; total knee arthroplasty

MeSH Terms

Arthroplasty
Axis, Cervical Vertebra
Congenital Abnormalities
Extremities
Femur
Follow-Up Studies
Humans
Knee

Figure

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  Figure 1 Preoperative radiograph of the knee, showing a deformity consisting of 16.8° of varus and 7.3° of flexion in the middle third of the femur.

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  Figure 2 Preoperative full-length anteroposterior radiograph of the lower extremity including the hip, knee, and ankle. The line perpendicular to the femoral mechanical axis shows the anticipated femoral condylar resection.

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  Figure 3 Pre and postoperative radiographs of total knee arthroplasty in patients with extra-articular deformity of the femur. (A) A 78-year-old man had the malunion of the femoral shaft. In the preoperative radiographs, the mechanical axis (MA) was varus 23.8° and the femorotibial angle (FTA) was varus 3.8°. (B) In the post operative 3.5 year radiographs, the MA was varus 0.8° and FTA was valgus 19.0°. There was no sign of loosening or infection.

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