We appreciate Dr Memişoğlu and Dr Atmaca’s helpful comments on our paper entiltled ‘Slipped capital femoral epiphysis: reduction as a risk factor for avascular necrosis’, and we would like to clarify some of the issues they raised.
We have indeed classified and grouped the preoperative and postoperative angles of our cases according to the severity, as proposed by Southwick 1. However, we understand that the amount of correction we achieve in slipped capital femoral epiphysis is more important that the initial angle. The correction depends not only on the acute status of the case but also on the amount of bone that had been remodeled previously on the femoral neck. It seems essential not to surpass the chronic component, and we can avoid this by using gentle maneuvers. We believe that the slip is rarely an acute case only. Besides, in these cases of evident instability, the relative position of the bone fragments is changeable, according to the radiograph incidences, and this is why the Lauenstein (frog leg) incidence is not indicated, as it can reduce the slip unintentionally.
Unfortunately, our follow-up period is not long enough to allow analyses of the long-term complications related to femoroacetabular impingement and early osteoarthrosis. We consider that avoiding chondrolysis and avascular necrosis, the earliest and most feared complications, confers some quality of life to these teenagers, even if they present some functional limitations for some periods. Currently, however, we agree that this is not enough and that something should be done to avoid residual deformities and their consequences in the medium and long term.
Recently, we published the preliminary analysis of five cases of severe acute-on-chronic slipped capital femoral epiphysis operated with a trapezoidal bony correction of the femoral neck using an arthroscopic approach 2. We began to operate using this technique in our pediatric orthopedic and trauma service in 2005. Despite being technically demanding, we were able to achieve deformity correction without using the open surgery. However, avascular necrosis still occurred in one case. As we described then, we believe that the necrosis in this case was because of insufficient bone resection in the inferior–posterior region, probably because of late presentation: the patient was referred to our center 60 days after the lesion, and we had to reduce it under tension, with a probable stretch of the residual vessels that fed the femoral neck.
In the past, we have treated several cases using the anterior hip open approach, carrying out a trapezoidal bone resection with a micropunch in the femoral neck, with a careful and gentle reduction, but we found high rates of complications such as chondrolysis and avascular necrosis 3. To date, we still have little experience with the open surgical dislocation proposed by Leunig et al. 4; thus, we cannot share any results yet, but we agree that it may be a valuable tool in experienced hands.
Conflicts of interest
There are no conflicts of interest.
1. Southwick WO. Osteotomy through the lesser trochanter for slipped capital femoral epiphysis. J Bone Joint Surg Am. 1967;49:807–835
2. Akkari M, Santili C, Braga SR, Polesello GC. Trapezoidal bony correction of the femoral neck in the treatment of severe acute-on-chronic slipped capital femoral epiphysis. Arthroscopy. 2010;26:1489–1495
3. Prado JCL, Santili C, Soni JF, Polesello G, Poedgaeti A. Slipped capital femoral epiphysis and its progressive acute form. Rev Bras Ortop. 1996;31:17–27
4. Leunig M, Slongo T, Kleinschmidt M, Ganz R. Subcapital correction osteotomy in slipped capital femoral epiphysis by means of surgical hip dislocation. Oper Orthop Traumatol. 2007;19:389–410