[Application of sliding osteotomy in total knee arthroplasty for patients with extra-articular femoral deformity].

OBJECTIVE

In order to observe the clinical effects of sliding osteotomy for patients with severe knee osteoarthritis and varus knee due to complex femoral extra-articular deformity to achieve the medial and lateral soft tissue balancing during total knee arthroplasty.

METHODS

From June 2014 to January 2018, a total of 22 patients with severe knee osteoarthritis and complex extra-articular malformation of femurs were treated with total knee arthroplasty. There were 5 males and 17 females in this group, aged 48 to 76 years old, with an average age of (61.3±13.8) years old. All the patients had varus deformities caused by extra-articular deformities of femur. Hip-knee-ankle(HKA) angle was(158.8±9.7) ° before operation, and the average Knee Society Score (KSS) clinical score was 32.6±6.1;KSS function score was 35.8 ±9.6;the average Hospital for Special Surgical (HSS) score was 39.7±4.6;the average range of motion before operation was (80.6±10.7) °. The mechanical alignment method was used in joint replacement. The flexion space was balanced first. The coronal plane vertical sliding osteotomy was performed on the medial femoral condyle for the imbalance of coronal plane. The sliding distance of the osteotomy block was determined by straightening the gap between the inner and outer sides of the space until the space was balanced. After the separated segments were fixed with several screws, the prosthesis was installed as usual.

RESULTS

The wounds of all patients healed in the first stage, and no wound complications occurred. All the 22 patients were followed up, and the duration ranged from 18 months to 3 years with an average of (28.2±10.1) months. X-ray showed that the fracture line disappeared for 2 to 5(3.5±1.5) months without nonunion. HKA angle measured at the latest follow up was (178.8±0.7) °, which wassignificantly different from that before operation. The HSS score was 91.3 ±6.0;KSS clinical score 93.7±3.5;KSS functional score 81.2±6.5;and the average range of motion of knee joint was(121.7±11.6) °, which was statistically significant compared with that before operation.

CONCLUSION

For severe knee osteoarthritis patients with complex femoral extra-articular deformity, sliding osteotomy is performed. For severe varus deformity, downward sliding the medial femoral condyle is performed. The operation is relatively simple and the damage is small. It is easy to achieve the balance of internal and external soft tissue in flexion extension space. The short-term clinical effect is satisfactory.