Retrograde dynamic locked nailing for valgus knee correction: a revised technique

Abstract

Purpose: Traditionally, valgus knee deformity is predominately corrected by stabilisation with a plate inserted via the medial approach to the supracondylar region of the femur. However, this technique is unfavourable from both a biomechanical and a biological point of view. A revised retrograde dynamic locked nailing was developed to improve correction of this defect.

Method: Forty-one knees with valgus deformity (average tibiofemoral angle, 22°; range, 16-29°) in 25 adult patients were treated by oblique femoral supracondylar varus osteotomy and stabilised with retrograde dynamic locked nails. Postoperatively, early ambulation with protected weight bearing and range of motion knee exercises were encouraged.

Result: Thirty-five knees of 21 patients were followed-up for an average of 2.6 years (range, 1.1-4.5 years). All osteotomy sites healed with an average union period of 3.4 months (range, 2.5-5.0 months). There were no significant complications. At the latest follow-up, the average tibiofemoral angle was 7.1° valgus (range, 4-10° valgus). For all of the knees, the outcomes were satisfactory (p < 0.001).

Conclusion: The technique described here may be a feasible alternative for correction of valgus knee deformity. The advantages of this technique include the use of a biomechanically more appropriate method, a minimal complication rate and a high rate of satisfactory outcomes.

Fig. 1

The steps involved in the modified femoral supracondylar varus osteotomy technique. a A valgus knee requires treatment. b A cutting line, orientated upwards and medially, is made 3-cm proximal to the lateral femoral condylar cortex. The angle between the cutting line and a vertical line to the lateral femoral cortex is equal to the desired angle of correction. c A second cutting line is made in the medial part of the distal fragment. The cutting line is perpendicular to the lateral femoral cortex with the removal of 1-cm of the medial cortex. d The anterior portion of the medial side of distal fragment is removed. e The distal fragment is realigned. The posterior portion of the medial side of the distal fragment is countersunk into the proximal fragment. f A rigid guide wire is used to establish a precise canal. g After, the rigid guide wire is changed to a flexible one and the marrow cavity is reamed as widely as possible. h A 1-mm smaller femoral locked nail is inserted and only the distal diagonal locked screw is inserted. Corticocancellous bone graft procured from the medial side is packed into the gap on the lateral side

Fig. 2

A 25-year-old woman with bilateral knee deformities and a tibiofemoral angle of 29° valgus was treated. Bilateral knee deformities were treated by the technique described. Both osteotomy sites healed at 3.5 months, and excellent outcomes were achieved at a 3.6-year follow-up. The tibiofemoral angle at the latest follow-up was 8° valgus

Fig. 3

A 52-year-old woman with a right knee deformity and a tibiofemoral angle of 24° valgus was treated. The knee deformity was treated with the technique described. A tibiofemoral angle of 7° valgus was achieved immediately after the operation. A cortical screw was used to treat the cortical splitting, which occurred during nail hammering. The osteotomy site healed at 4.0 months and an excellent outcome was achieved at the four-year follow-up. The tibiofemoral angle at the latest follow-up was 6° valgus