Slipped Capital Femoral Epiphysis - In-Situ Screw Fixation

Simon P. Kelley, MBChB, FRCS (Tr and Orth)
The Hospital for Sick Children
Assistant Professor, Department of Surgery
University of Toronto

M. Lucas Murnaghan, M.D., MEd, FRCSC
The Hospital for Sick Children
Assistant Professor, Department of Surgery
University of Toronto
Toronto, ON

Five years ago, a survey of the Paediatric Orthopaedic Society of North America (POSNA) membership on the management of unstable Slipped Capital Femoral Epiphysis (SCFE) found remarkable agreement on the gold standard treatment of in-situ screw fixation (ISSF)1. Two years later, similar results were identified in a comparable study of British and Dutch paediatric orthopaedic surgeons2. Uniformity of management is particularly unusual in the specialty of paediatric orthopaedics where a wide range of treatment options are often available for the conditions that we treat, resting on a tenuous foundation of scientific evidence. SCFE is one of the most common paediatric orthopaedic conditions that we see not only in teaching centres, but also in every community hospital across Canada. The majority of these patients will not be managed by paediatric orthopaedic specialists with expertise in complex hip surgery. It is therefore of legitimate concern that controversy once again surrounds the treatment of unstable SCFE with the emergence of surgical hip dislocation and open reduction and internal fixation (ORIF) as an alternative to ISSF.

 

In reviewing the literature on the topic of SCFE, the reviewer finds a wealth of research that is unfortunately limited to mostly Level IV or V studies1. A variety of treatment strategies have been described - including both operative and non-operative management3-5. ISSF has risen above all other strategies as a reliable and safe procedure with a low complication rate5, 6. Without a formal reduction manoeuvre, some gentle internal rotation whilst positioning the limb may effect a modest reduction of the SCFE, minimizing the severity of the slip, prior to percutaneous screw fixation. The near-universal adoption of ISSF is likely due to the fact that it relies on equipment and implants being available at most institutions and a surgical technique that is transferable from other common orthopaedic procedures. Within a training program it is easily taught and supervised, while in the community setting it can be performed with minimal surgical assistance. Advocates of ISSF have continued to modify the technique, improving the procedure to address several technical issues. Modern imaging methods have improved the accuracy of screw placement7 to minimize the risk of joint penetration and the risk of AVN or chondrolysis. The use of two image intensifiers for biplanar fluoroscopy or a 3D CT C-arm are new additions to the radiographic armamentarium to improve procedural accuracy. Previous issues with the internal fixation devices have been reduced with the use of cannulated screw fixation in preference to multiple pins. Complications related to screw removal8 are likely to be improved with the demonstration that fully threaded screws may offer some advantages to their partially threaded counterparts9. Recent work has brought attention to the increased intra-capsular pressure that exists in cases of unstable SCFE10. The release of this hematoma through an anterior or lateral approach can decrease the intra-capsular pressure and potentially decrease the risk of avascular necrosis. The improvements of the classic ISSF to a more contemporary version have addressed many key concerns and have improved an already successful treatment strategy.

KELLYFig1

Figure 1: 13-year-old male with a three-month history of mild left groin pain, suddenly increasing in severity over 24 hours, and inability to weight bear. Managed by gentle internal rotation of the limb while positioning, capsulotomy and in-situ screw fixation with a 7.3 mm fully threaded cannulated screw. Images show preop, immediate postop and three-month follow-up radiographs.

Orthopaedic surgeons should not feel that they are offering substandard treatment by way of ISSF. There is very little, if any, evidence to justify the benefits of the alternative experimental procedure of surgical hip dislocation and ORIF over the established gold standard. Surgical hip dislocation is a technically challenging procedure with potentially devastating complications and limited options for salvage. Though there is intuitive benefit to an anatomic reduction to prevent the sequelae of femoroacetabular impingement, the outcomes of the technique are as yet unproven. There will almost certainly be a place for more complex reconstructive procedures of the hip in SCFE, though we firmly believe that any new procedure should be subject to the rigours of scientific scrutiny in the setting of clinical trials. Should surgical hip dislocation and ORIF then prove to be at least as efficacious as ISSF for the treatment of unstable SCFE, with an equally low morbidity and complication rate and similar reproducibility, then it should be widely adopted. Until then, the gold standard of treatment of unstable SCFE should remain as contemporary ISSF.

References

  1. Mooney, J.F., 3rd, et al., Management of unstable/acute slipped capital femoral epiphysis: results of a survey of the POSNA membership. J Pediatr Orthop, 2005. 25(2): p. 162-6.
  2. Witbreuk, M., P. Besselaar, and D. Eastwood, Current practice in the management of acute/unstable slipped capital femoral epiphyses in the United Kingdom and the Netherlands: results of a survey of the membership of the British Society of Children's Orthopaedic Surgery and the Werkgroep Kinder Orthopaedie. J Pediatr Orthop B, 2007. 16(2): p. 79-83.
  3. Ward, W.T., et al., Fixation with a single screw for slipped capital femoral epiphysis. J Bone Joint Surg Am, 1992. 74(6): p. 799-809.
  4. Aronson, D.D. and W.E. Carlson, Slipped capital femoral epiphysis. A prospective study of fixation with a single screw. J Bone Joint Surg Am, 1992. 74(6): p. 810-9.
  5. Aronson, D.D., D.A. Peterson, and D.V. Miller, Slipped capital femoral epiphysis. The case for internal fixation in situ. Clin Orthop Relat Res, 1992(281): p. 115-22.
  6. Carney, B.T., S.L. Weinstein, and J. Noble, Long-term follow-up of slipped capital femoral epiphysis. J Bone Joint Surg Am, 1991. 73(5): p. 667-74.
  7. Westberry, D.E., et al., Simultaneous biplanar fluoroscopy for the surgical treatment of slipped capital femoral epiphysis. J Pediatr Orthop, 2008. 28(1): p. 43-8.
  8. Raney, E.M., et al., Evidence-based analysis of removal of orthopaedic implants in the pediatric population. J Pediatr Orthop, 2008. 28(7): p. 701-4.
  9. Miyanji, F., et al., Biomechanical comparison of fully and partially threaded screws for fixation of slipped capital femoral epiphysis. J Pediatr Orthop, 2008. 28(1): p. 49-52.
  10. Herrera-Soto, J.A., et al., Increased intracapsular pressures after unstable slipped capital femoral epiphysis. J Pediatr Orthop, 2008. 28(7): p. 723-8.

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