Correction of distal femoral valgus deformities with fixator-assisted plating: How accurate is the correction?

Acta Orthopaedica et Traumatologica Turcica 53 (2019) 100e105 Contents lists available at ScienceDirect Acta Orthopaedica et Traumatologica Turcica journal homepage: https://www.elsevier.com/locate/aott Correction of distal femoral valgus deformities with fixator-assisted plating: How accurate is the correction? lu Güney Yılmaz*, Sancar Bakırcıog Hacettepe University, Department of Orthopaedics and Traumatology, Turkey a r t i c l e i n f o a b s t r a c t Article history: Received 13 July 2018 Received in revised form 29 August 2018 Accepted 28 November 2018 Available online 13 December 2018 Objective: The aim of this study was to evaluate the results of fixator assisted correction of the distal femoral valgus deformities and the precision of the correction. Methods: Seventeen extremities of 13 patients (7 women and 6 men; mean age: 16 ± 5.4 years) who had fixator assisted plating of the distal femur for genu valgum deformity were evaluated. Mechanical axis deviation (MAD) and mechanical lateral distal femoral angles (mLDFA) were measured pre-operatively and post-operatively. mLDFA was graded as perfect if it is between 85
and 90
(85
 x  90
); overcorrection if it is between 91
and 95
(91
 x  95
) and undercorrection if it is between 80
and 85
(80
 x < 85
). Measurements beyond those limits were graded as a poor result. The position of the mechanical axis line with respect to center of the knee was graded from zone 1 to zone 4 pre-operatively and post-operatively. Results: The mean follow-up period was 12.8 ± 3.7 months. The pre-operative and post-operative mLDFA was 70.5
±9.4
(range, 57
e82
) and 87.7
± 3.5
(range, 80
e94
), respectively (p < 0.001). Based on post-operative standing radiographs, the correction was graded perfect in 12 femurs. The correction in three femurs were graded as overcorrection and graded as undercorrection in two femurs. Sagittal plane correction was also achieved in two femurs. Peroneal nerve decompression was done in three patients (5 extremities) with valgus deformity over 30
. The mechanical axes in all lower extremities were passing through zone 2 or more, pre-operatively, whereas the mechanical axes were in zone 2 or more in five extremities post-operatively. Conclusion: Fixator assisted plating is an effective treatment modality in patients with distal femoral valgus deformity. Although the technique enables to obtain significant correction in coronal plane it has the disadvantages of over- and undercorrection. Thus, we advise intraoperative confirmation of the correction under fluoroscopic control. Level of Evidence: Level IV Therapeutic Study. © 2018 Turkish Association of Orthopaedics and Traumatology. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/). Keywords: Fixator assisted plating Femur osteotomy Genu valgum Valgus deformity Deformity Correction Introduction The deformities effecting the long bones of the lower extremity may emerge from variety of reasons including trauma sequela, metabolic disorders, skeletal dysplasias, infection and congenital limb deficiencies. Long term effect of malalignment in lower extremity is unpredictable. The valgus and varus deformities may * Corresponding author. Hacettepe University Faculty of Medicine, 06100 Sıhhiye, Ankara, Turkey. Tel.: þ90 0 3123051249. Fax: þ90 0 312 3100580. E-mail address: (G. Yılmaz). Peer review under responsibility of Turkish Association of Orthopaedics and Traumatology. predispose to pain, knee instability, ligament injury and cartilage degeneration. In addition, those deformities around the knee may deteriorate ambulatuar capacity of an individual patient.1e3 Several treatment options exist for distal femur deformities including growth guided surgery, osteotomy and external fixation or internal fixation. Guided growth utilizing staples or tension band plating is an effective method in patients with open growth plates.4 Although good results have been reported with guided growth in patients having enough growth potential with mild to moderate deformities, the efficacy of the technique has been questioned in obese patients, in patients whose growth plates are close to maturity and in patients with severe mechanical axis deviation.5 Osteotomy and gradual correction through circular frames https://doi.org/10.1016/j.aott.2018.11.002 1017-995X/© 2018 Turkish Association of Orthopaedics and Traumatology. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). G. Yılmaz, S. Bakırcıoglu / Acta Orthopaedica et Traumatologica Turcica 53 (2019) 100e105 101 (ilizarov/hexapod frames) is the treatment of choice in patients who has multiplanar deformities along with limb length inequality. External fixation systems have their own drawbacks including pin site infections, knee stiffness and the discomfort related to frame itself.6,7 Fixator assisted distal femur correction and retrograde intramedullary nailing has been applied in patients with closed growth plates.8 Since the intramedullary rod violates the growth plates, this technique is not recommended in pediatric age group. Fixator assisted distal femur osteotomy and internal fixation is another option for femur deformities. Good results has been reported utilizing temporary external fixation in order to achieve and maintain correction and then fixation of the osteotomy site with a locking distal femur plate.9 Eidelman et al recommended that the technique shouldn't be used in patients with open growth plates and multiapical deformities. As opposed to original technique we have been using the fixator assisted correction and plating for distal femoral uniplanar and biplanar deformities in pediatric (open growth plates) and adult age group. We report the early clinical and radiological results of these patients in the current study emphasizing on the accuracy of the correction. Materials and method This retrospective study was approved by University Ethics Commission. 13 patients (17 extremities) who had fixator assisted plating of the distal femur for genu valgum deformity were evaluated. Pre-operatively all patients were evaluated with long standing lower extremity radiographs and deformity analysis were completed. Deformity apexis were determined and the osteotomies were planned. Mechanical axis deviation (MAD) and mechanical lateral distal femoral angles (mLDFA) were measured pre-operatively and post-operatively. Post-operative mLDFA was graded as perfect if it was between 85
and 90
(85
 x  90
); overcorrection if it is between 91
and 95
(91
 x  95
) and undercorrection if it is between 80
and 85
(80
 x < 85
). Measurements beyond those limits were graded as bad result. The translation created at the osteotomy site during correction was also calculated as a percentage of the horizontal leng (...truncated)