Accuracy and Safety of Distal Femoral Valgus Correction: A Comparison of Three Techniques

There are several methods for correcting distal femoral valgus deformity in skeletally mature patients including fixator-assisted plating (FAP), fixator-assisted nailing (FAN) and nailing using the reverse planning method. The fixator-assisted techniques have been previously compared in the literature and found to be similarly accurate. This study is the first to compare all three procedures in a single series.

A retrospective review of patients who had undergone distal femoral valgus correction at a single institution between March 2017 and February 2020 was undertaken. Three different patient groups were identified based on the surgical technique used: the FAP, the FAN and the reverse planning method. The mechanical lateral distal fimoral angle (mLDFA) was recorded and compared preoperatively and postoperatively. The body mass index (BMI), duration of surgery, postoperative range of motion (ROM) and complication profile for each patient were also recorded and compared.

A total of 27 limbs in 24 patients were included in this study. There were 8 male and 16 female patients. There were 10 limbs from 9 patients in the reverse planning group, 11 limbs from 11 patients in the FAN group and 6 limbs from 4 patients in the FAP group. There was a statistically significant difference in the mean preoperative and postoperative mLDFA for each of the individual groups (p < 0.0001 for each group). All patients had restoration of the mLDFA to within normal limits except one patient in the reverse planning group. This was purposefully performed to compensate for an ipsilateral proximal tibial deformity. There was no statistically significant difference in the mean preoperative and postoperative mLDFA across the groups (p = 0.2897 and 0.3440, respectively). The operative time of the reverse planning method and the FAP were significantly shorter than FAN (p = 0.0016 and p = 0.0035, respectively). The mean final knee ROM amongst the groups was similar (p = 0.8190). We recorded no infections or union complications in any group. There was one case of hardware irritation causing lateral knee pain that did not require treatment in the reverse planning group and one fracture through a temporary half-pin site in the FAN group. All six plates in the FAP group had to be removed following union on account of localised discomfort from the hardware.

The reverse planning method, the FAN and the FAP are comparable in terms of accuracy in achieving correction of distal femur valgus deformity in skeletally mature patients. The reverse planning method had the best combination of outcomes in this study since it was just as accurate as the FAN and the FAP techniques and did not require any additional surgeries. While both the reverse planning and the FAP were faster than the FAN technique, the reverse planning method allows the ability to perform both deformity correction and lengthening. Ultimately, the decision of which technique to use depends on a combination of the patient's preference and the surgeon's level of comfort with the technique.

Iobst C, Waseemuddin M, Bafor A. Accuracy and Safety of Distal Femoral Valgus Correction: A Comparison of Three Techniques. Strategies Trauma Limb Reconstr 2020;15(1):41-46.