Effect of soft tissue balance in total knee replacement of varus knee

Objective To analyze contribution of varus knee with osteoarthritis and investigate the role of soft tissue balance in total knee replacement ( TKR) of that. Methods One hundred cases (145 varus knees) were operated with TKR. There were 18 males (25 knees) and 82 females (120 knees), with the average age of 64.6 years, from 45 to 80 years old. During the operation, accurate osteotomy and soft tissue balance was made to correct the varus knee joint. The contribution angles of varus knee was measured on weight bearing X ray images pre and postoperatively, in order to evaluate the results of the combination of the osteotomy and soft tissue balance. Results The gross varus angle was average 9.2° ± 3.1° , ranging from 5° to 30° preoperatively. In the total angle, the varus angle caused by soft tissue imbalance was 53.2% , the osseous varus angles caused by the tibia varus was 22.8% , the osseous varus angles caused by tibia plateau destruction was 24.0% . The measurement of the postoperative X ray films suggested that the average angle of the tibia plateau osteotomy was 4.3° , obtaining the correction of 27.9% of the total varus angle, and the angles corrected by soft tissue balance was 10.7° ,getting the correction of 72.1% of the total varus angle. According to HSS score system, the preoperative score was 38 points, ranging from 5 to 57, and postoperative scores was 87 points, ranging from 75 to 90. Conclusion The contribution of varus knee with osteoarthritis were include: 1) Bony structural varus angle composed of tibial varus and tibial plateau destruction; 2) Collateral ligaments and soft tissue imbalance around the knee. Articular surface destruction and soft tissue imbalance are the main contribution of varus knee. For TKR of varus knees like this, besides accurate osteotomy, correct soft tissue balance is the key of the operation. [