Case for Open Reduction and Fixation of Acute SCFE

Young-Jo Kim, M.D.
Associate Professor of Orthopaedic Surgery
Children's Hospital-Boston
Boston, MA

Acute unstable Slipped Capital Femoral Epiphysis (SCFE) is defined clinically by the inability to walk, even with assistive devices1. This condition behaves like a true femoral neck fracture and is associated with rate of avascular necrosis (AVN) as high as 47%. Often the resulting deformity from the SCFE is severe and the natural history of SCFE suggests that moderate to severe deformities have a high likelihood of causing premature osteoarthritis2. Current controversy regarding the management of an unstable SCFE stems from the need to balance the risk of developing avascular necrosis (from the inherent injury and/or surgical manipulation) with the benefits of minimizing the deformity. Although this issue remains controversial, more recent data suggest that open reduction of an unstable SCFE may be beneficial compared to in-situ pinning.

 

KIMFig_1
Figure 1: Preoperative films (A, B) show severe unstable SCFE in a 12-year-old girl. After modified Dunn procedure (C, D) the proximal femoral anatomy is restored without AVN.

There is universal agreement that forceful manipulation of any SCFE is contraindicated. However, inadvertent reduction or gentle closed manipulation is thought to not increase the inherent high rate of avascular necrosis. Sankar et al3. compared the rates of avascular necrosis in 70 unstable SCFE hips treated with closed vs. open reduction and found that the rate of AVN was higher in the closed reduction group (19-26%) compared to the open reduction group (6%). However, they did not have sufficient power to show statistical significance. Parsch et al.4 have demonstrated that in the truly unstable SCFE, evacuation of the hematoma and a gentle open reduction can result in a fairly low (4.7%) rate of AVN. Therefore, it would appear that an open reduction and gentle open manipulation will not increase the rate of AVN and may, in fact, lower the rate of AVN compared to in-situ pinning or gentle closed manipulation and pinning.

Leunig, et al5, 6 have advocated the use of surgical dislocation to perform the subcapital realignment. This may prove to be safe and will allow full correction of the proximal femoral deformity that would otherwise result in early functional limitations and eventual osteoarthritis. The surgical dislocation approach in itself appears to be safe with almost zero rate of AVN and a low rate of trochanteric delayed union7. Ziebarth et al8 have shown in 40 cases of moderate to severe SCFE reconstruction using the modified Dunn procedure, that this procedure could be performed with reasonably low risk of AVN

(0 out of 40) and full restoration of normal anatomy and function. However, it remains to be seen if this technically demanding procedure can be performed in other centres with the same level of safety. The main advantage of the modified Dunn procedure through a safe surgical dislocation approach is the 1) ability to fully correct the deformity and 2) ability to identify the avascular head (due to stretching of the retinacular vessels) and to surgically restore the blood flow. Figure 1 illustrates a case of 12-year-old girl with severe unstable SCFE. Modified Dunn osteotomy was performed and at time of surgery the femoral head was initially avascular (Figure 2A). After freeing of the femoral neck periostium, the femoral head blood supply was restored (Figure 2B,C).

Using any approach, the risk of AVN in an unstable SCFE is unlikely to approach zero. However, accepting a rate of AVN that can range up to nearly 50% when treated using closed methods seems illogical. Open reduction through an anterior arthrotomy does not appear to increase the rate of AVN as compared to closed treatment and may in fact decrease the rate of AVN as well the amount of proximal femoral deformity. The modified Dunn procedure has the advantage of allowing full correction of the deformity as well as the ability to identify avascular heads and possibly restore blood flow; however, it is a technically demanding procedure with the risk of iatrogentic AVN.

In summary, for an unstable acute SCFE, at a minimum, anterior open reduction and pinning should be performed and in experienced hands, a modified Dunn procedure should be considered.

KIMFig_2
Figure 2: Initially the femoral head was avascular (A). After freeing the retinacular vessels the femoral head blood supply was restored (B, C).

References

  1. Loder, R.T., B.S. Richards, P.S. Shapiro, L.R. Reznick, and D.D. Aronson, Acute slipped capital femoral epiphysis: the importance of physeal stability. J Bone Joint Surg Am, 1993. 75(8): p. 1134-40.
  2. Carney, B.T. and S.L. Weinstein, Natural history of untreated chronic slipped capital femoral epiphysis. Clin Orthop Relat Res, 1996(322): p. 43-7.
  3. Sankar, W.N., T.G. McPartland, M.B. Millis, and Y.J. Kim, The unstable slipped capital femoral epiphysis: risk factors for osteonecrosis. J Pediatr Orthop. 30(6): p. 544-8.
  4. Parsch, K., S. Weller, and D. Parsch, Open reduction and smooth Kirschner wire fixation for unstable slipped capital femoral epiphysis. J Pediatr Orthop, 2009. 29(1): p. 1-8.
  5. Leunig, M., T. Slongo, and R. Ganz, Subcapital realignment in slipped capital femoral epiphysis: surgical hip dislocation and trimming of the stable trochanter to protect the perfusion of the epiphysis. Instr Course Lect, 2008. 57: p. 499-507.
  6. Leunig, M., T. Slongo, M. Kleinschmidt, and R. Ganz, Subcapital correction osteotomy in slipped capital femoral epiphysis by means of surgical hip dislocation. Oper Orthop Traumatol, 2007. 19(4): p. 389-410.
  7. Ganz, R., T.J. Gill, E. Gautier, K. Ganz, N. Krugel, and U. Berlemann, Surgical dislocation of the adult hip a technique with full access to the femoral head and acetabulum without the risk of avascular necrosis. J Bone Joint Surg Br, 2001. 83(8): p. 1119-24.
  8. Ziebarth, K., C. Zilkens, S. Spencer, M. Leunig, R. Ganz, and Y.J. Kim, Capital realignment for moderate and severe SCFE using a modified Dunn procedure. Clin Orthop Relat Res, 2009. 467(3): p. 704-16.

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