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Available online at
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Original article
Evolution of slipped capital femoral epiphysis after in situ screw fixation at a mean 11 years’ follow-up: A 222 case series E. Nectoux a,∗ , J. Décaudain a , F. Accadbled b , A. Hamel c , N. Bonin d , P. Gicquel e , and the French society of Orthopedic, Traumatologic Surgery (SoFCOT)f a
Chirurgie et orthopédie de l’enfant, hôpital Jeanne-de-Flandre, CHRU Lille, avenue Eugène-Avinée, 59037 Lille cedex, France Service d’orthopédie-traumatologie pédiatrique, hôpital des enfants, CHU de Toulouse, 330, avenue de Grande-Bretagne, 31059 Toulouse cedex 9, France c Service de chirurgie infantile, CHU de Nantes, 38, boulevard Jean-Monnet, 44093 Nantes cedex 1, France d LyonOrthoClinic, 29B, avenue des Sources, 69009 Lyon, France e Service d’orthopédie-traumatologie pédiatrique, hôpital de Hautepierre, CHU de Strasbourg, 1, avenue Molière, 67098 Strasbourg cedex, France f 56, rue Boissonade, 75014 Paris, France b
a r t i c l e
i n f o
Article history: Accepted 17 November 2014 Keywords: Slipped capital femoral epiphysis In situ screw fixation Femoroacetabular impingement
a b s t r a c t Introduction: Slipped capital femoral epiphysis (SCFE) can lead to hip impingement, more or less rapidly depending on initial slippage severity and on surgical technique. Various surgical options are applicable, including in situ fixation (ISF). The aim of the present study was to look for long-term signs of radiological impingement in hips treated for SCFE by IFS, in order to identify a slip threshold beyond which impingement more regularly appears. Material and methods: A multicenter retrospective study assessed the clinical and radiological evolution of patients operated on by ISF for SCFE, with a minimum 10 year’s follow-up. Coxometric analysis of postoperative and last follow-up radiographs was performed. Functional outcome was assessed on Oxford hip score and radiographic osteoarthritis on the Tönnis classification. Alpha angle was measured on lateral views to highlight hip impingement. Results: Two hundred and twenty-two hips were included, with a mean 11.2 years’ follow-up. Mean age at diagnosis was 12.8 years. Mean preoperative Southwick angle was 38.8◦ , with 43% of hips at stage I, 42% at stage II and 15% at stage III. At latest follow-up, mean Oxford score was 14.86, with 88% of hips rated Tönnis 0 or I. Only 15 cases of impingement were diagnosed. There seemed to be a non-significant trend for hip impingement in SCFE exceeding 35◦ . Conclusion: ISF led to hip impingement in moderate to severe initial epiphyseal displacement. However, in smaller displacement, the consequences were milder, with perfectly satisfactory function scores and no clinical or radiological evidence of impingement. The threshold seemed to be around 35◦ slippage, beyond which other surgical options than ISF should be considered. Thus, it seems reasonable to propose isolated ISF in SCFE < 35◦ and to treat symptomatic impingement by surgery in stage II slips. © 2014 Elsevier Masson SAS. All rights reserved.
1. Introduction Slipped capital femoral epiphysis (SCFE) is the most frequent hip complaint in adolescents. Treatment seeks to prevent worsening of epiphyseal slippage on the metaphysis, and percutaneous in situ fixation (ISF) using a single cannulated screw has long shown efficacy [1]. Residual deformity may nevertheless lead to femoroacetabular impingement or osteoarthritis of the hip in the medium-to-long-term [2]. The present study reviewed SCFE
∗ Corresponding author. Tel.: +33 3 20 44 47 54; fax: +33 3 20 44 50 74. E-mail address: [email protected] (E. Nectoux).
patients managed by ISF at a minimum 10 years’ follow-up, to assess clinical and radiological outcome according to initial Southwick slip angle. The secondary objective was to determine a slip threshold as of which femoroacetabular impingement became more frequent after isolated ISF. 2. Material and methods A multicenter (Lille, Berck, Marseille, Toulouse, Strasbourg) retrospective study included all cases of uni- or bi-lateral, stable or unstable SCFE managed by ISF using 1 cannulated screw, with a minimum 10 years’ follow-up. Exclusion criteria were: surgery by head repositioning, and history of bone disease. Preoperative
http://dx.doi.org/10.1016/j.otsr.2014.12.004 1877-0568/© 2014 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Nectoux E, et al. Evolution of slipped capital femoral epiphysis after in situ screw fixation at a mean 11 years’ follow-up: A 222 case series. Orthop Traumatol Surg Res (2015), http://dx.doi.org/10.1016/j.otsr.2014.12.004
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ARTICLE IN PRESS E. Nectoux et al. / Orthopaedics & Traumatology: Surgery & Research xxx (2015) xxx–xxx
Statistical analysis was performed by the biostatistics laboratory of Lille University Hospital. A descriptive analysis was made, with comparative analysis of each parameter on non-parametric Wilcoxon test for small samples. The significance threshold was set at P < 0.05. Correlations between preoperative variables and onset of impingement were assessed on Spearman correlation coefficient. 3. Results
Fig. 1. AP view, right hip, 27-year-old male. Managed at 13 years by in situ fixation for slipped capital femoral epiphysis with 58◦ slip. Cannulated screw removed at 1.5 years. At 14 years’ follow-up, lateral metaphyseal convexity and herniation pit, left by the acetabulum on the femoral neck in hip abduction. Simple impairment of abduction. Oxford score, 20. No signs of osteoarthritis. Surgery not indicated, as no patient demand.
radiography comprised Dunn lateral hip view, with measurement of the Southwick posterior slip angle [3], considered pathological when greater than 7◦ . SCFE was classified according to three grades of increasing severity: stage I, 7–30◦ ; stage II, 31–60◦ ; and stage III, > 60◦ . The preoperative study variables were thus: age at diagnosis, SCFE stage, and Southwick slip angle. Surgical data confirmed that the technique systematically involved ISF. Postoperative radiological data were assessed on anteroposterior (AP) hip view and Dunn lateral view. Coxometry comprised measurement of the VCA, VCE, AR and CCD angles (vertical-center-anterior, vertical-center-edge, acetabular roof, and caput-collum-diaphyseal angles, respectively). Minimum follow-up was 10 years. Clinical examination screened for femoroacetabular impingement, with clinical assessment on the Oxford-12 Hip score [4]. Radiologic assessment comprised the same data as on immediate postoperative assessment, plus the alpha angle on lateral view, described by Nötzli et al. [5]; this is the angle subtended by: • a line between the center of the femoral neck and the center of the femoral head; • a line between the center of the femoral head and the point at which the head becomes non-spherical. Radiographic osteoarthritis was assessed on the Tönnis classification [6]. Signs of femoroacetabular impingement comprised: convexity at the junction between femoral head and neck, head flatness, osteophytes, and herniation pit (Fig. 1). Any revision surgery, other than to remove the cannulated screw after growth-plate fusion (not considered as a revision procedure), was noted.
Two hundred and twenty-two patients were included (222 hips), with minimum 10 years’ follow-up. There were 131 boys (59%) and 91 girls, with a mean age at diagnosis of 12.8 years (standard deviation, 2.06 years). Involvement was of the left hip in 61% of cases (136 patients). Mean preoperative Southwick angle was 38.8◦ (range, 14–70◦ ). Slip severity was 43% stage I (n = 53), 42.3% stage II (n = 52) and 14.7% stage III (n = 18). Mean age at last follow-up was 28.2 years, for a mean follow-up of 11.2 years. At last follow-up, mean AR angle was 11.4◦ (range, 3–46◦ ), VCE angle 30◦ (10–68◦ ) and VCA angle 31◦ (8–70◦ ). There were no significant differences between preoperative versus follow-up coxometric variables (P < 0.05). Mean alpha angle at follow-up was 69◦ (range, 27–110◦ ; normal value, < 50◦ ). Mean global Oxford score was 14.86, corresponding to satisfactory joint function not requiring formal treatment (range, 12–37). Eighty-eight percent of hips were Tönnis grade 0 or 1 at follow-up (122 grade 0 and 73 grade 1): i.e., free of osteoarthritis or incipient signs, such as moderate joint-line impingement. Seventeen hips underwent revision surgery during the mean 11.2 years’ follow-up. There were 4 main indications: femoroacetabular impingement in 6 cases, disabling pain due to advanced osteoarthritis in 6 cases, head necrosis in 3 cases, and joint impingement due to excessively long fixation screws in 2 cases (with early revision). Fifteen hips showed pain in flexion and/or abduction, correlating with signs of femoroacetabular impingement; 6 of these had undergone surgical revision. The Wilcoxon test for small samples found no link between pre- or postoperative Southwick angle and onset of femoroacetabular impingement. The Wilcoxon two-sample test performed in all cases of revision, on the other hand, revealed a correlation between preoperative Southwick angle and occurrence of surgical revision (P = 0.019). Spearman correlation between preoperative Southwick angle and severity on follow-up Oxford score showed a highly significant coefficient of 0.0003: the greater the angle, the poorer the score. ROC survival curves, to determine an epiphyseal slip threshold beyond which impingement would be significantly more frequent and Oxford score impaired, plotting onset of impingement against preoperative Southwick angle, found median sensitivity and specificity both around 0.53 (i.e., non-significant) for 35.5–39.5◦ slip; there was thus a non-significant trend for impingement after ISF in SCFE exceeding 35.5–39.5◦ . In the same analysis performed on all patients with Oxford score > 12 (i.e., in pain), the ROC curve for onset of pain according to initial epiphyseal slip found comparable sensitivity and specificity around 0.53 for 35.5–39.5◦ slip. 4. Discussion The present study found that functional prognosis (on Oxford hip score) was related to initial epiphyseal slip. There appeared to be a 35◦ threshold beyond which femoroacetabular impingement became more frequent; this bears out literature reports [7–11]. In the 222 hips, there were only 15 cases of femoroacetabular impingement and little medium-term osteoarthritis, with 88% of
Please cite this article in press as: Nectoux E, et al. Evolution of slipped capital femoral epiphysis after in situ screw fixation at a mean 11 years’ follow-up: A 222 case series. Orthop Traumatol Surg Res (2015), http://dx.doi.org/10.1016/j.otsr.2014.12.004
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patients graded 0 or 1 on the Tönnis classification; this is less in line with the literature. Monin et al. [7] found a 60% rate of osteoarthritis at a mean 19 years’ follow-up, and actually 100% at 10 years in case of > 40◦ slip. Wensaas et al. [12] found significantly greater incidence of radiological signs of femoroacetabular impingement (convexity, flattening, osteophytes and herniation pit) after isolated ISF at 37 years’ follow-up compared to a control population free of hip pathology. One hypothesis to explain the relative sparseness of clinical as compared to radiological signs is based on the pathophysiology of anatomic remodeling. DeLullo et al. [13] found that operated patients generally showed very satisfactory evolution, but with slightly poorer function and pain scores than in an age-matched reference population; femoral head-neck junction remodelling may play a role in this. In the present series, there was no significant difference in AR, VCA or VCE angles between immediate postoperative values and those at a mean 11.2 years’ follow-up. Mean VCA and VCE angles at the upper limits of normal clearly indicate downward and backward displacement of the femoral head. Remodelling of the acetabular side should thus apparently not be relied upon. Alpha angle could not be measured on postoperative view, but at last follow-up had a mean value of 69◦ , indicating that the impact of remodelling of the femoral head-neck junction convexity was slight. The study thus confirms the marginal involvement of bone remodelling in short-to-medium-term course after ISF for SCFE. To the best of our knowledge, this is the first report of such coxometric results in SCFE with such long follow-up. Statistical analysis disclosed a trend for more frequent femoroacetabular impingement beyond a threshold 35.5◦ epiphyseal slip; the trend was non-significant, but in line with the literature [7–11]. It thus seems reasonable to perform only isolated ISF in SCFE with Southwick angle < 35◦ ; beyond 35◦ , management concerns incipient femoroacetabular impingement as well as in situ fixation itself. Certain authors take the same attitude even with very low Southwick angles, especially with an arthroscopic approach, which becomes technically more difficult beyond 30◦ slip [14]. Ilizaliturri et al. [15] reported 8 cases of secondary treatment in which the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score improved by 9.6 points without complications (P < 0.001). Leunig et al. [16], in a preliminary study, even suggested associating arthroscopy to ISF in a single step; followup is presently insufficient to assess this option. Moreover, the femoroacetabular impingement induced by epiphyseal slippage is not focal as in adults, making complete arthroscopic treatment of slip-related impingement very complicated [14]. In the literature, most studies of osteochondroplasty by hip dislocation, with or without intertrochanteric osteotomy, reported relief of hip impingement symptoms. The osteochondroplasty is not performed in the same step as ISF [17–19]. This surgery, however, often leaves a residual metaphyseal convexity, regularly leading to trochanteric non-union and intra-articular adherence [20]. Superior femoral derotation and valgization osteotomy has long been described and may be associated to osteochondroplasty of the femoral neck if need be [21]. The interval at which proximal femoral osteotomy should be performed remains controversial, and the present non-significant results do not tip the balance in favour of one-step ISF with osteotomy, as recommended by Witbreuk et al. [22]. Finally, peri-acetabular osteotomy, as described by Ganz et al., may be associated to ISF in a single step. This option has been reported for SCFE sequelae, but should be reserved to cases of acetabular retroversion associated with extensive defect in the posterior acetabular wall [23]. Thus, a review of the literature combined to the present findings failed to support a more aggressive primary attitude in ISF
3
for SCFE between 35◦ and 60◦ . Moreover, at 11.2 years’ followup, there were few cases of femoroacetabular impingement in the present series. Eighty-eight percent of patients showed little or no osteoarthritis on Tönnis score and had very satisfactory Oxford function scores. It thus seems reasonable to consider treating femoroacetabular impingement only when it becomes symptomatic rather than proposing heavier surgery from the outset. Disclosure of interest The authors declare that they have no conflicts of interest concerning this article. References [1] Goodman WW, Johnson JT, Robertson Jr WW. Single screw fixation for acute and acute-on-chronic slipped capital femoral epiphysis. J Bone Joint Surg Am 1996;74:799–809. [2] Hosalkar HS, Pandya NK, Bomar JD, Wenger DR. Hip impingement in slipped capital femoral epiphysis: a changing perspective. J Child Orthop 2012;6:161–72. [3] Southwick WO. Osteotomy through the lesser trochanter for slipped capital femoral epiphysis. J Bone Joint Surg Am 1967;49:807–35. [4] Delaunay C, Epinette JA, Dawson J, Murray D, Jolles BM. Cross-cultural adaptations of the Oxford-12 HIP score to the French speaking population. Orthop Traumatol Surg Res 2009;95:89–99. [5] Nötzli HP, Wyss TF, Stoecklin CH, Schmid MR, Treiber K, Hodler J. The contour of the femoral head-neck junction as a predictor for the risk of anterior impingement. J Bone Joint Surg Br 2002;84:556–60. [6] Tönnis D, Heinecke A. Acetabular and femoral anteversion: relationship with osteoarthritis of the hip. J Bone Joint Surg Am 1999;81:1747– 70. [7] Monin JO, Gouin F, Guillard S, Rogez JM. Late results of the treatment of the slipped upper femoral epiphysis (26 cases with follow-up study over 10 years). Rev Chir Orthop 1995;81:35–43. [8] Ross PM, Lyne ED, Morawa LG. Slipped capital femoral epiphysis longterm results after 10–38 years. Clin Orthop Relat Res 1979;141:176– 80. [9] Stevens DB, Short BA, Burch JM. In situ fixation of the slipped capital femoral epiphysis with a single screw. J Pediatr Orthop B 1996;5: 85–9. [10] Millis MB, Novais EN. In situ fixation for slipped capital femoral epiphysis: perspectives in 2011. J Bone Joint Surg Am 2011;93(Suppl. 2): 46–51. [11] Hansson G, Billing L, Hogstedt B, Jerre R, Wallin J. Long-term results after nailing in situ of slipped upper femoral epiphysis. A 30-year follow-up of 59 hips. J Bone Joint Surg Br 1998;80:70–7. [12] Wensaas A, Gunderson RB, Svenningsen S, Terjesen T. Femoroacetabular impingement after slipped upper femoral epiphysis: the radiological diagnosis and clinical outcome at long-term follow-up. J Bone Joint Surg Br 2012;94:1487–93. [13] DeLullo JA, Thomas E, Cooney TE, McConnell SJ, Sanders JO. Femoral remodeling may influence patient outcomes in slipped capital femoral epiphysis. Clin Orthop Relat Res 2007;457:163–70. [14] Jayakumar P, Ramachandran M, Youm T, Achan P. Arthroscopy for the hip in paediatric and adolescent disorders. J Bone Joint Surg Br 2012;94–B: 290–6. [15] Ilizaliturri Jr VM, Nossa-Barrera JM, Acosta-Rodriguez E, CamachoGalindo J. Arthroscopic treatment of femoroacetabular impingement secondary to paediatric hip disorders. J Bone Joint Surg Br 2007;89–B: 1025–30. [16] Leunig M, Horowitz K, Manner H, Ganz R. In situ pinning with arthroscopic osteoplasty for mild SCFE: a preliminary technical report. Clin Orthop Relat Res 2010;468:3160–7. [17] Ganz R, Gill TJ, Gautier E, et al. 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–B:1119–24. [18] Rebello G, Spencer S, Millis MB, Kim Y. Surgical dislocation in the management of pediatric and adolescent hip deformity. Clin Orthop Relat Res 2009;467:724–31. [19] Spencer S, Millis MB, Kim YJ. Early results of treatment for hip impingement syndrome in slipped capital femoral epiphysis and pistol grip deformity of the femoral head-neck junction using the surgical dislocation technique. J Pediatr Orthop 2006;26:281–5. [20] Matsuda DK, Carlisle JC, Arthurs SC, Wierks C, Philippon MJ. Comparative systematic review of the open dislocation, mini-open and arthroscopic surgeries for femoroacetabular impingement. Arthroscopy 2011;27: 252–69. [21] Whiteside LA, Schoenecker PL. Combined valgus derotation osteotomy and cervical osteoplasty for severely slipped capital femoral epiphysis:
Please cite this article in press as: Nectoux E, et al. Evolution of slipped capital femoral epiphysis after in situ screw fixation at a mean 11 years’ follow-up: A 222 case series. Orthop Traumatol Surg Res (2015), http://dx.doi.org/10.1016/j.otsr.2014.12.004
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mechanical analysis and report preliminary results using compression screw fixation and early weight bearing. Clin Orthop Relat Res 1978;132: 88–97. [22] Witbreuk M, Bolkenbaas M, Mullender MG, Sierevelt IN, Besselaar PP. The results of downgrading moderate and severe slipped capital femoral
epiphysis by an early Imhauser femur osteotomy. J Child Orthop 2009;3: 405–10. [23] Siebenrock KA, Schoeninger R, Ganz R. Anterior femoroacetabular impingement due to acetabular retroversion: treatment with peri-acetabular osteotomy. J Bone Joint Surg Am 2003;85–A:278–86.
Please cite this article in press as: Nectoux E, et al. Evolution of slipped capital femoral epiphysis after in situ screw fixation at a mean 11 years’ follow-up: A 222 case series. Orthop Traumatol Surg Res (2015), http://dx.doi.org/10.1016/j.otsr.2014.12.004
ARTICLE IN PRESS Orthopaedics & Traumatology: Surgery & Research xxx (2015) xxx–xxx
Available online at
ScienceDirect www.sciencedirect.com
Original article
Evolution of slipped capital femoral epiphysis after in situ screw fixation at a mean 11 years’ follow-up: A 222 case series E. Nectoux a,∗ , J. Décaudain a , F. Accadbled b , A. Hamel c , N. Bonin d , P. Gicquel e , and the French society of Orthopedic, Traumatologic Surgery (SoFCOT)f a
Chirurgie et orthopédie de l’enfant, hôpital Jeanne-de-Flandre, CHRU Lille, avenue Eugène-Avinée, 59037 Lille cedex, France Service d’orthopédie-traumatologie pédiatrique, hôpital des enfants, CHU de Toulouse, 330, avenue de Grande-Bretagne, 31059 Toulouse cedex 9, France c Service de chirurgie infantile, CHU de Nantes, 38, boulevard Jean-Monnet, 44093 Nantes cedex 1, France d LyonOrthoClinic, 29B, avenue des Sources, 69009 Lyon, France e Service d’orthopédie-traumatologie pédiatrique, hôpital de Hautepierre, CHU de Strasbourg, 1, avenue Molière, 67098 Strasbourg cedex, France f 56, rue Boissonade, 75014 Paris, France b
a r t i c l e
i n f o
Article history: Accepted 17 November 2014 Keywords: Slipped capital femoral epiphysis In situ screw fixation Femoroacetabular impingement
a b s t r a c t Introduction: Slipped capital femoral epiphysis (SCFE) can lead to hip impingement, more or less rapidly depending on initial slippage severity and on surgical technique. Various surgical options are applicable, including in situ fixation (ISF). The aim of the present study was to look for long-term signs of radiological impingement in hips treated for SCFE by IFS, in order to identify a slip threshold beyond which impingement more regularly appears. Material and methods: A multicenter retrospective study assessed the clinical and radiological evolution of patients operated on by ISF for SCFE, with a minimum 10 year’s follow-up. Coxometric analysis of postoperative and last follow-up radiographs was performed. Functional outcome was assessed on Oxford hip score and radiographic osteoarthritis on the Tönnis classification. Alpha angle was measured on lateral views to highlight hip impingement. Results: Two hundred and twenty-two hips were included, with a mean 11.2 years’ follow-up. Mean age at diagnosis was 12.8 years. Mean preoperative Southwick angle was 38.8◦ , with 43% of hips at stage I, 42% at stage II and 15% at stage III. At latest follow-up, mean Oxford score was 14.86, with 88% of hips rated Tönnis 0 or I. Only 15 cases of impingement were diagnosed. There seemed to be a non-significant trend for hip impingement in SCFE exceeding 35◦ . Conclusion: ISF led to hip impingement in moderate to severe initial epiphyseal displacement. However, in smaller displacement, the consequences were milder, with perfectly satisfactory function scores and no clinical or radiological evidence of impingement. The threshold seemed to be around 35◦ slippage, beyond which other surgical options than ISF should be considered. Thus, it seems reasonable to propose isolated ISF in SCFE < 35◦ and to treat symptomatic impingement by surgery in stage II slips. © 2014 Elsevier Masson SAS. All rights reserved.
1. Introduction Slipped capital femoral epiphysis (SCFE) is the most frequent hip complaint in adolescents. Treatment seeks to prevent worsening of epiphyseal slippage on the metaphysis, and percutaneous in situ fixation (ISF) using a single cannulated screw has long shown efficacy [1]. Residual deformity may nevertheless lead to femoroacetabular impingement or osteoarthritis of the hip in the medium-to-long-term [2]. The present study reviewed SCFE
∗ Corresponding author. Tel.: +33 3 20 44 47 54; fax: +33 3 20 44 50 74. E-mail address: [email protected] (E. Nectoux).
patients managed by ISF at a minimum 10 years’ follow-up, to assess clinical and radiological outcome according to initial Southwick slip angle. The secondary objective was to determine a slip threshold as of which femoroacetabular impingement became more frequent after isolated ISF. 2. Material and methods A multicenter (Lille, Berck, Marseille, Toulouse, Strasbourg) retrospective study included all cases of uni- or bi-lateral, stable or unstable SCFE managed by ISF using 1 cannulated screw, with a minimum 10 years’ follow-up. Exclusion criteria were: surgery by head repositioning, and history of bone disease. Preoperative
http://dx.doi.org/10.1016/j.otsr.2014.12.004 1877-0568/© 2014 Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Nectoux E, et al. Evolution of slipped capital femoral epiphysis after in situ screw fixation at a mean 11 years’ follow-up: A 222 case series. Orthop Traumatol Surg Res (2015), http://dx.doi.org/10.1016/j.otsr.2014.12.004
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ARTICLE IN PRESS E. Nectoux et al. / Orthopaedics & Traumatology: Surgery & Research xxx (2015) xxx–xxx
Statistical analysis was performed by the biostatistics laboratory of Lille University Hospital. A descriptive analysis was made, with comparative analysis of each parameter on non-parametric Wilcoxon test for small samples. The significance threshold was set at P < 0.05. Correlations between preoperative variables and onset of impingement were assessed on Spearman correlation coefficient. 3. Results
Fig. 1. AP view, right hip, 27-year-old male. Managed at 13 years by in situ fixation for slipped capital femoral epiphysis with 58◦ slip. Cannulated screw removed at 1.5 years. At 14 years’ follow-up, lateral metaphyseal convexity and herniation pit, left by the acetabulum on the femoral neck in hip abduction. Simple impairment of abduction. Oxford score, 20. No signs of osteoarthritis. Surgery not indicated, as no patient demand.
radiography comprised Dunn lateral hip view, with measurement of the Southwick posterior slip angle [3], considered pathological when greater than 7◦ . SCFE was classified according to three grades of increasing severity: stage I, 7–30◦ ; stage II, 31–60◦ ; and stage III, > 60◦ . The preoperative study variables were thus: age at diagnosis, SCFE stage, and Southwick slip angle. Surgical data confirmed that the technique systematically involved ISF. Postoperative radiological data were assessed on anteroposterior (AP) hip view and Dunn lateral view. Coxometry comprised measurement of the VCA, VCE, AR and CCD angles (vertical-center-anterior, vertical-center-edge, acetabular roof, and caput-collum-diaphyseal angles, respectively). Minimum follow-up was 10 years. Clinical examination screened for femoroacetabular impingement, with clinical assessment on the Oxford-12 Hip score [4]. Radiologic assessment comprised the same data as on immediate postoperative assessment, plus the alpha angle on lateral view, described by Nötzli et al. [5]; this is the angle subtended by: • a line between the center of the femoral neck and the center of the femoral head; • a line between the center of the femoral head and the point at which the head becomes non-spherical. Radiographic osteoarthritis was assessed on the Tönnis classification [6]. Signs of femoroacetabular impingement comprised: convexity at the junction between femoral head and neck, head flatness, osteophytes, and herniation pit (Fig. 1). Any revision surgery, other than to remove the cannulated screw after growth-plate fusion (not considered as a revision procedure), was noted.
Two hundred and twenty-two patients were included (222 hips), with minimum 10 years’ follow-up. There were 131 boys (59%) and 91 girls, with a mean age at diagnosis of 12.8 years (standard deviation, 2.06 years). Involvement was of the left hip in 61% of cases (136 patients). Mean preoperative Southwick angle was 38.8◦ (range, 14–70◦ ). Slip severity was 43% stage I (n = 53), 42.3% stage II (n = 52) and 14.7% stage III (n = 18). Mean age at last follow-up was 28.2 years, for a mean follow-up of 11.2 years. At last follow-up, mean AR angle was 11.4◦ (range, 3–46◦ ), VCE angle 30◦ (10–68◦ ) and VCA angle 31◦ (8–70◦ ). There were no significant differences between preoperative versus follow-up coxometric variables (P < 0.05). Mean alpha angle at follow-up was 69◦ (range, 27–110◦ ; normal value, < 50◦ ). Mean global Oxford score was 14.86, corresponding to satisfactory joint function not requiring formal treatment (range, 12–37). Eighty-eight percent of hips were Tönnis grade 0 or 1 at follow-up (122 grade 0 and 73 grade 1): i.e., free of osteoarthritis or incipient signs, such as moderate joint-line impingement. Seventeen hips underwent revision surgery during the mean 11.2 years’ follow-up. There were 4 main indications: femoroacetabular impingement in 6 cases, disabling pain due to advanced osteoarthritis in 6 cases, head necrosis in 3 cases, and joint impingement due to excessively long fixation screws in 2 cases (with early revision). Fifteen hips showed pain in flexion and/or abduction, correlating with signs of femoroacetabular impingement; 6 of these had undergone surgical revision. The Wilcoxon test for small samples found no link between pre- or postoperative Southwick angle and onset of femoroacetabular impingement. The Wilcoxon two-sample test performed in all cases of revision, on the other hand, revealed a correlation between preoperative Southwick angle and occurrence of surgical revision (P = 0.019). Spearman correlation between preoperative Southwick angle and severity on follow-up Oxford score showed a highly significant coefficient of 0.0003: the greater the angle, the poorer the score. ROC survival curves, to determine an epiphyseal slip threshold beyond which impingement would be significantly more frequent and Oxford score impaired, plotting onset of impingement against preoperative Southwick angle, found median sensitivity and specificity both around 0.53 (i.e., non-significant) for 35.5–39.5◦ slip; there was thus a non-significant trend for impingement after ISF in SCFE exceeding 35.5–39.5◦ . In the same analysis performed on all patients with Oxford score > 12 (i.e., in pain), the ROC curve for onset of pain according to initial epiphyseal slip found comparable sensitivity and specificity around 0.53 for 35.5–39.5◦ slip. 4. Discussion The present study found that functional prognosis (on Oxford hip score) was related to initial epiphyseal slip. There appeared to be a 35◦ threshold beyond which femoroacetabular impingement became more frequent; this bears out literature reports [7–11]. In the 222 hips, there were only 15 cases of femoroacetabular impingement and little medium-term osteoarthritis, with 88% of
Please cite this article in press as: Nectoux E, et al. Evolution of slipped capital femoral epiphysis after in situ screw fixation at a mean 11 years’ follow-up: A 222 case series. Orthop Traumatol Surg Res (2015), http://dx.doi.org/10.1016/j.otsr.2014.12.004
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patients graded 0 or 1 on the Tönnis classification; this is less in line with the literature. Monin et al. [7] found a 60% rate of osteoarthritis at a mean 19 years’ follow-up, and actually 100% at 10 years in case of > 40◦ slip. Wensaas et al. [12] found significantly greater incidence of radiological signs of femoroacetabular impingement (convexity, flattening, osteophytes and herniation pit) after isolated ISF at 37 years’ follow-up compared to a control population free of hip pathology. One hypothesis to explain the relative sparseness of clinical as compared to radiological signs is based on the pathophysiology of anatomic remodeling. DeLullo et al. [13] found that operated patients generally showed very satisfactory evolution, but with slightly poorer function and pain scores than in an age-matched reference population; femoral head-neck junction remodelling may play a role in this. In the present series, there was no significant difference in AR, VCA or VCE angles between immediate postoperative values and those at a mean 11.2 years’ follow-up. Mean VCA and VCE angles at the upper limits of normal clearly indicate downward and backward displacement of the femoral head. Remodelling of the acetabular side should thus apparently not be relied upon. Alpha angle could not be measured on postoperative view, but at last follow-up had a mean value of 69◦ , indicating that the impact of remodelling of the femoral head-neck junction convexity was slight. The study thus confirms the marginal involvement of bone remodelling in short-to-medium-term course after ISF for SCFE. To the best of our knowledge, this is the first report of such coxometric results in SCFE with such long follow-up. Statistical analysis disclosed a trend for more frequent femoroacetabular impingement beyond a threshold 35.5◦ epiphyseal slip; the trend was non-significant, but in line with the literature [7–11]. It thus seems reasonable to perform only isolated ISF in SCFE with Southwick angle < 35◦ ; beyond 35◦ , management concerns incipient femoroacetabular impingement as well as in situ fixation itself. Certain authors take the same attitude even with very low Southwick angles, especially with an arthroscopic approach, which becomes technically more difficult beyond 30◦ slip [14]. Ilizaliturri et al. [15] reported 8 cases of secondary treatment in which the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score improved by 9.6 points without complications (P < 0.001). Leunig et al. [16], in a preliminary study, even suggested associating arthroscopy to ISF in a single step; followup is presently insufficient to assess this option. Moreover, the femoroacetabular impingement induced by epiphyseal slippage is not focal as in adults, making complete arthroscopic treatment of slip-related impingement very complicated [14]. In the literature, most studies of osteochondroplasty by hip dislocation, with or without intertrochanteric osteotomy, reported relief of hip impingement symptoms. The osteochondroplasty is not performed in the same step as ISF [17–19]. This surgery, however, often leaves a residual metaphyseal convexity, regularly leading to trochanteric non-union and intra-articular adherence [20]. Superior femoral derotation and valgization osteotomy has long been described and may be associated to osteochondroplasty of the femoral neck if need be [21]. The interval at which proximal femoral osteotomy should be performed remains controversial, and the present non-significant results do not tip the balance in favour of one-step ISF with osteotomy, as recommended by Witbreuk et al. [22]. Finally, peri-acetabular osteotomy, as described by Ganz et al., may be associated to ISF in a single step. This option has been reported for SCFE sequelae, but should be reserved to cases of acetabular retroversion associated with extensive defect in the posterior acetabular wall [23]. Thus, a review of the literature combined to the present findings failed to support a more aggressive primary attitude in ISF
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for SCFE between 35◦ and 60◦ . Moreover, at 11.2 years’ followup, there were few cases of femoroacetabular impingement in the present series. Eighty-eight percent of patients showed little or no osteoarthritis on Tönnis score and had very satisfactory Oxford function scores. It thus seems reasonable to consider treating femoroacetabular impingement only when it becomes symptomatic rather than proposing heavier surgery from the outset. Disclosure of interest The authors declare that they have no conflicts of interest concerning this article. References [1] Goodman WW, Johnson JT, Robertson Jr WW. Single screw fixation for acute and acute-on-chronic slipped capital femoral epiphysis. J Bone Joint Surg Am 1996;74:799–809. [2] Hosalkar HS, Pandya NK, Bomar JD, Wenger DR. Hip impingement in slipped capital femoral epiphysis: a changing perspective. J Child Orthop 2012;6:161–72. [3] Southwick WO. Osteotomy through the lesser trochanter for slipped capital femoral epiphysis. J Bone Joint Surg Am 1967;49:807–35. [4] Delaunay C, Epinette JA, Dawson J, Murray D, Jolles BM. Cross-cultural adaptations of the Oxford-12 HIP score to the French speaking population. Orthop Traumatol Surg Res 2009;95:89–99. [5] Nötzli HP, Wyss TF, Stoecklin CH, Schmid MR, Treiber K, Hodler J. The contour of the femoral head-neck junction as a predictor for the risk of anterior impingement. J Bone Joint Surg Br 2002;84:556–60. [6] Tönnis D, Heinecke A. Acetabular and femoral anteversion: relationship with osteoarthritis of the hip. J Bone Joint Surg Am 1999;81:1747– 70. [7] Monin JO, Gouin F, Guillard S, Rogez JM. Late results of the treatment of the slipped upper femoral epiphysis (26 cases with follow-up study over 10 years). Rev Chir Orthop 1995;81:35–43. [8] Ross PM, Lyne ED, Morawa LG. Slipped capital femoral epiphysis longterm results after 10–38 years. Clin Orthop Relat Res 1979;141:176– 80. [9] Stevens DB, Short BA, Burch JM. In situ fixation of the slipped capital femoral epiphysis with a single screw. J Pediatr Orthop B 1996;5: 85–9. [10] Millis MB, Novais EN. In situ fixation for slipped capital femoral epiphysis: perspectives in 2011. J Bone Joint Surg Am 2011;93(Suppl. 2): 46–51. [11] Hansson G, Billing L, Hogstedt B, Jerre R, Wallin J. Long-term results after nailing in situ of slipped upper femoral epiphysis. A 30-year follow-up of 59 hips. J Bone Joint Surg Br 1998;80:70–7. [12] Wensaas A, Gunderson RB, Svenningsen S, Terjesen T. Femoroacetabular impingement after slipped upper femoral epiphysis: the radiological diagnosis and clinical outcome at long-term follow-up. J Bone Joint Surg Br 2012;94:1487–93. [13] DeLullo JA, Thomas E, Cooney TE, McConnell SJ, Sanders JO. Femoral remodeling may influence patient outcomes in slipped capital femoral epiphysis. Clin Orthop Relat Res 2007;457:163–70. [14] Jayakumar P, Ramachandran M, Youm T, Achan P. Arthroscopy for the hip in paediatric and adolescent disorders. J Bone Joint Surg Br 2012;94–B: 290–6. [15] Ilizaliturri Jr VM, Nossa-Barrera JM, Acosta-Rodriguez E, CamachoGalindo J. Arthroscopic treatment of femoroacetabular impingement secondary to paediatric hip disorders. J Bone Joint Surg Br 2007;89–B: 1025–30. [16] Leunig M, Horowitz K, Manner H, Ganz R. In situ pinning with arthroscopic osteoplasty for mild SCFE: a preliminary technical report. Clin Orthop Relat Res 2010;468:3160–7. [17] Ganz R, Gill TJ, Gautier E, et al. 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–B:1119–24. [18] Rebello G, Spencer S, Millis MB, Kim Y. Surgical dislocation in the management of pediatric and adolescent hip deformity. Clin Orthop Relat Res 2009;467:724–31. [19] Spencer S, Millis MB, Kim YJ. Early results of treatment for hip impingement syndrome in slipped capital femoral epiphysis and pistol grip deformity of the femoral head-neck junction using the surgical dislocation technique. J Pediatr Orthop 2006;26:281–5. [20] Matsuda DK, Carlisle JC, Arthurs SC, Wierks C, Philippon MJ. Comparative systematic review of the open dislocation, mini-open and arthroscopic surgeries for femoroacetabular impingement. Arthroscopy 2011;27: 252–69. [21] Whiteside LA, Schoenecker PL. Combined valgus derotation osteotomy and cervical osteoplasty for severely slipped capital femoral epiphysis:
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mechanical analysis and report preliminary results using compression screw fixation and early weight bearing. Clin Orthop Relat Res 1978;132: 88–97. [22] Witbreuk M, Bolkenbaas M, Mullender MG, Sierevelt IN, Besselaar PP. The results of downgrading moderate and severe slipped capital femoral
epiphysis by an early Imhauser femur osteotomy. J Child Orthop 2009;3: 405–10. [23] Siebenrock KA, Schoeninger R, Ganz R. Anterior femoroacetabular impingement due to acetabular retroversion: treatment with peri-acetabular osteotomy. J Bone Joint Surg Am 2003;85–A:278–86.
Please cite this article in press as: Nectoux E, et al. Evolution of slipped capital femoral epiphysis after in situ screw fixation at a mean 11 years’ follow-up: A 222 case series. Orthop Traumatol Surg Res (2015), http://dx.doi.org/10.1016/j.otsr.2014.12.004
