Surgical treatment for shepherd's crook deformity in fibrous dysplasia: THERE IS NO BEST, ONLY BETTER.

Background: The optimal strategy for shepherd's crook deformity correction remains technically challenging. In particular, it is difficult to perform an accurate osteotomy based on the pre-operative correction plan. Moreover, the choice of ideal hardware remains unclear. In addition, when combined with the deformity of knee joint, the sequence of deformity correction is another overlooked factor when making a correction strategy.

Methods: From February 2012 to March 2014, we retrospectively examined a cases series in our department involving the creation of three-dimensional (3D) printing osteotomy templates and inner fixation for shepherd's crook deformity in fibrous dysplasia.

Results: A total of ten patients of shepherd's crook deformity were enrolled in this study. The neck shaft angle was corrected from a mean value of 88.1° (range, 73-105°) pre-operatively to a mean value of 128.5° (range, 120-135°) post-operatively; no marked loss in the value was observed (mean, 123.7°; range, 115-130°) at the final follow-up. In addition, compared with patients using dynamic hip screw (DHS), longer operation time and additional blood loss were recorded in patients using intramedullary nail (IN). Moreover, after correction of shepherd's crook deformity, two patients were observed more predominant on their pre-existing valgus knee deformity.

Conclusions: 3D printing osteotomy templates facilitate the correction of shepherd's crook deformity. Dynamic hip screw (DHS), combined with polymethylmethacrylate (PMMA) augmentation, yields excellent outcomes and ensures easy placement and non-intramedullary manipulation, lower bleeding volume, and reduced operation time. Prior to the correction of shepherd's crook deformity, the mechanical axis of the lower limb should be carefully examined, and any evidence of valgus knee deformity should be addressed in advance.