Arthroscopic Subcapital Realignment in Chronic and Stable Slipped Capital Femoral Epiphysis Bruno Dutra Roos, M.D., Marcelo Camargo de Assis, M.D., M.S., Milton Valdomiro Roos, M.D., Antero Camisa Júnior, M.D., and Ezequiel Moreno Ungaretti Lima, M.D.
Abstract: Stable slipped capital femoral epiphysis (SCFE) is the most common disease in the adolescent hip, with an estimated frequency of 10.8 in every 100,000 individuals. Recent studies of the biomechanics of femoroacetabular impingement indicate that small anatomical deformities of the hip arising from SCFE can potentially cause permanent acetabular chondral damage. There is no consensus about the best treatment option, especially for cases of moderate or severe chronic slippage (Southwick classification). Some authors recommend treatment with fixation in situ, in the belief that remodeling of the residual deformity of the femoral neck during growth allows proper function of the hip joint. Others recommend correction at the site of the deformity (subcapital realignment), aiming for the anatomical reduction of the epiphysis and seeking to reduce the risk of chondral degeneration. The authors of this Technical Note present an alternative to the classical techniques of subcapital realignment for the treatment of moderate and severe chronic and stable SCFE, which allows adequate access to the hip joint and anatomical reduction of the slippage, besides having the theoretical advantage of rapid rehabilitation of the patient.
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ome authors have suggested that small anatomical deformities arising from slipped capital femoral epiphysis (SCFE) can potentially cause permanent acetabular chondral damage, leading to early osteoarthrosis.1,2 In cases of chronic moderate or severe slippage (according to the Southwick classification3), one of the treatment possibilities is subcapital realignment, which allows correction at the site of the deformity, aiming for the anatomical reduction of the epiphysis and seeking to reduce the risk of subsequent chondral degeneration.4 The authors’ main criticism against the use of this technique is the risk of complications, such as avascular necrosis of the femoral head (AVN) and chondrolysis, which can occur in up to 28% of cases.5 However, the growing number of studies inthis area has enabled the minimization of
From the Hip Surgery Group, Hospital Ortopédico de Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil. The authors report the following potential conflicts of interest or sources of funding: B.D.R. receives support from Passo Fundo Orthopedic Hospital. Received September 20, 2016; accepted January 23, 2017. Address correspondence to Bruno Dutra Roos, M.D., Hip Surgery Group, Hospital Ortopédico de Passo Fundo, Rua 7 de Setembro, 817, Centro, Passo Fundo, Rio Grande do Sul, Brazil. E-mail: [email protected] Ó 2017 by the Arthroscopy Association of North America 2212-6287/16909/$36.00 http://dx.doi.org/10.1016/j.eats.2017.01.017
complications, with careful observation of technical details, such as preserving the vascular supply to the epiphysis during the procedure, being fundamental.4 The aim of this Technical Note is to describe an arthroscopic technique of subcapital realignment for the treatment of moderate and severe chronic and stable SCFE in patients with open physis. The work described here was carried out in accordance with the Code of Ethics of the World Medical Association (Declaration of Helsinki).
Surgical Technique The surgical technique for arthroscopic subcapital realignment in chronic and stable SCFE is shown in Video 1. General anesthesia with femoral nerve block is used. Physical examination of the hip is conducted with the patient under anesthesia to passively evaluate the bilateral range of movement. The patient is positioned in the supine position on a regular radiolucent table. The orthopaedic traction table is not used because of the need for greater mobility of the hip for the multiple transoperative maneuvers. The pelvis is slightly tilted to the contralateral side, and a radiotransparent pad is placed under the hemipelvis to be operated on (Fig 1). The anatomical references are marked using an appropriate pen. A vertical line is demarcated from the
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Fig 1. Preoperative radiographic images of a patient with left-sided chronic and stable slipped capital femoral epiphysis (SCFE). (A) An anterior posterior pelvic radiograph. The site of the slippage (growth plate) is shown with the white arrows. (B) A frog-leg lateral view radiograph showing an epiphyseal-diaphyseal angle of 54 . The site of the slippage is shown with the white arrows. The neoformed bone tissue in the posteromedial region of the femoral neck is shown with the yellow arrow. The bump deformity created by progression and chronification of the SCFE is shown with the red arrow. The dashed lines show the epiphysealdiaphyseal angle measure.
anterosuperior iliac spine to the center of the patella. The anterior, posterior, and proximal borders of the greater trochanter of the femur are also marked. Portals are positioned with the aid of fluoroscopy. The first is the mid-anterior portal, which is the camera portal. The second portal, the anterolateral portal, is placed in a location that allows access parallel to the physis, which is the working portal (Fig 2). The arthroscopic approach that we use for the subcapital realignment is the extracapsular one, which follows the access to the peripheral joint compartment, as described by Sampson.6 With the limb to be operated in the neutral position, and after establishing the arthroscopic portals, the
Fig 2. Preoperative photograph of a patient positioned for a left hip arthroscopy showing the portal placement. The mid-anterior portal (MAPd1) is the camera portal. The anterolateral portal (ALPd2) is placed in a location that allows access parallel to the physis (1 cm proximal and anterior to the original site), which is the working portal. The fluoroscopic image shows the projection of the mid-anterior (1) and anterolateral (2) portals.
anterior joint capsule and iliocapsular muscle are dissected, using radiofrequency (SERFAS, Stryker, Kalamazoo, MI) and a shaver (Stryker), until adequate exposure is achieved. T-capsulotomy is then performed on the femoral neck, which may be extended as necessary. Next, capsulectomy is performed, to achieve adequate exposure of the anterior region of the metaphysis and epiphysis of the proximal femur, in its mid-lateral extension (Fig 3). After sufficient exposure, femoral osteochondroplasty of the femoral head-neck junction is performed, which allows resection of the bump deformity created by progression and chronification of the SCFE, and better
Fig 3. View of a left hip through a 30 arthroscope in a midanterior portal. The extracapsular arthroscopic approach is used for exposure of the slipped capital femoral epiphysis. The arrows indicate the site of the slippage (growth plate) between the femoral head (FH) and the femoral neck (FN). (L, labrum.)
ARTHROSCOPIC SUBCAPITAL REALIGNMENT IN SCFE
Fig 4. View of a left hip through a 30 arthroscope in a mid-anterior portal. Femoral osteochondroplasty of the femoral head-neck junction is performed, which allows resection of the bump deformity created by progression and chronification of the slipped capital femoral epiphysis, and better identification of the physis. In more severe cases of slippage, external rotation of the limb may be necessary to expose the physis. (FH, femoral head; FN, femoral neck.)
identification of the physis (Fig 4). In more severe cases of slippage, external rotation of the limb may be necessary to expose the physis. The cupuliform osteotomy is performed 2 mm distal to the growth plate (to facilitate shortening of the femoral neck later) using a specific curved osteotome (Muzymed, Canoas, Brazil) guided by fluoroscopic assistance (Fig 5). Iatrogenic articular cartilage damage must be avoided.
Fig 5. View of a left hip through a 30 arthroscope in a midanterior portal. The cupuliform osteotomy is performed 2 mm distal to the growth plate (to facilitate shortening of the femoral neck later) using a specific curved osteotome inserted through the anterolateral portal. (CO, curved osteotome; P, physis.)
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Fig 6. View of a left hip through a 30 arthroscope in a midanterior portal. After the osteotomy, the hip is rotated externally with slight traction, to allow shortening of the femoral neck and resection of the growth plate using an arthroscopic curette and burr. After shortening, the hip is adducted to remove neoformed bone tissue in the posteromedial region of the femoral neck, which could impede the subsequent reduction. The red asterisk indicates the neoformed bone tissue, and the arrow the epiphysis. (AC, arthroscopic curette; FN, femoral neck.)
With the femoral neck separated from the epiphysis, the hip is rotated externally, with slight traction, to allow shortening of the femoral neck and resection of the growth plate using an arthroscopic curette (Muzymed) and burr (Stryker). After shortening, the hip is adducted to remove neoformed bone tissue in the posteromedial region of the femoral neck, which could
Fig 7. View of a left hip through a 30 arthroscope in a mid-anterior portal. Bleeding of the epiphysis can be observed after the osteotomy. (B, bleeding of the epiphysis; E, epiphysis; FN, femoral neck.)
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Fig 8. Transoperative frog-leg lateral fluoroscopic view of a left hip after the reduction of the epiphysis and stabilization with 2 guidewires. The dashed lines show a step between the epiphysis and the femoral neck, suggesting the reduction of the epiphysis.
impede the subsequent reduction (Fig 6). The amount of neck shortening and posteromedial bone resection is determined by trial and error through gentle reduction and fluoroscopic prechecking in the anterior-posterior view. Direct arthroscopic visualization of the reduction is not reliable and may be difficult due to bleeding, but is suggested by the presence of a step between the epiphysis and the femoral neck. The vascular viability of the epiphysis can be directly checked at any time, or by making a small perforation in it (Fig 7). The retinacular vessels are difficult to visualize. Finally, the hip is flexed, abducted, and internally rotated to reduce the epiphysis. The final reduction is checked by fluoroscopy in the anterior-posterior and frog-leg lateral view after stabilization of the epiphysis with 2 guidewires. A 6.5-mm partially threaded cannulated screw is used for percutaneous fixation (Figs 8-10). Active and passive joint movements are stimulated in the immediate postoperative period. Two crutches are used, and full weight bearing is allowed after 4 weeks (Table 1).
SCFE can potentially cause permanent acetabular chondral damage.4 Ganz et al.8 described the use of surgical dislocation of the hip when performing modified Dunn’s osteotomy (subcapital realignment) in the treatment of unstable9 and/or high-grade3 SCFE. According to the authors, this approach allows access to the hip, preserving the vascular supply to the epiphysis, with adequate resection of posteromedial bone neoformation of the femoral neck and satisfactory reduction of the epiphysis. Thus, the goal of restoring the anatomy of the proximal femur is achieved, using a technique that minimizes the risk of AVN.8 Leunig et al.1 showed labral and acetabular chondral lesions in 14 patients with unstable SCFE9 during subcapital realignment using the technique of surgical dislocation of the hip, and observed that these lesions occurred when the femoral metaphysis was at or beyond the epiphyseal line.1 Similarly, Sink et al.,2 using the same surgical technique, showed the presence of intra-articular lesions in 39 patients with SCFE, with 34 labral and 33 chondral injuries. Several authors have published the results of the use of the technique described by Ganz et al.,8 but with some complications. Sankar et al.,10 in a multicenter study that evaluated 27 patients with unstable SCFE,9 with a mean follow-up of 22.3 months, found 4 patients (15%) who needed revision surgery because of failure of the fixation, and 7 cases (26%) of AVN. The mean postoperative evolution for osteonecrosis was 21.4 weeks, and the patients who did not evolve with this complication presented significantly lower clinical pain scores, and higher postoperative satisfaction.10 Upasani et al.11 presented the results of 43 patients treated using this technique: 60% of the cases were patients with unstable SCFE9; 40% were considered acute; and 86% were classified as
Discussion SCFE is the most common pathology in the adolescent hip, with an estimated frequency of 10.8 in every 100,000 individuals.7 Recent studies of the biomechanics of femoroacetabular impingement indicate that small anatomical deformities of the hip arising from
Fig 9. Postoperative photograph of a patient after a left hip arthroscopy for subcapital realignment in chronic and stable slipped capital femoral epiphysis, showing the aspect of the wound closure. X indicates the portal sites and the asterisk the percutaneous fixation site.
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Fig 10. Three-year and two-month postoperative radiographic images of a left-sided slipped capital femoral epiphysis. (A) An anterior posterior pelvic radiograph showing the postoperative correction of the slippage. (B) A frog-leg lateral view radiograph showing an epiphyseal-diaphyseal angle of 4 . The white arrow indicates the correction of the deformity. The dashed lines indicate the epiphyseal-diaphyseal angle measure.
severe slippage.3 Twenty-two complications were observed in 16 patients, with 15 revision surgeries due to AVN, failure of the fixation, and postoperative dislocation of the hip. Two patients needed indication for total hip arthroplasty.11 The most published studies on arthroscopic treatment of SCFE basically focus on the treatment of complications of the disease. Wylie et al.12 described femoral osteochondroplasty in 9 patients with residual deformity of SCFE after fixation in situ. Similarly, Chen et al.13 presented satisfactory results in 88% of patients after performing femoral osteochondroplasty on 37 patients. In acute on chronic cases, 2 authors reported trapezoidal osteotomy for arthroscopic treatment of SCFE. Akkari et al.14 presented the results of 5 cases, obtaining an average preoperative epiphyseal-diaphyseal angle3 of 82 , and an average postoperative angle of 14 , with 1 case evolving to AVN.14 Dobashi et al.15
presented a case report of severe acute on chronic SCFE in a 12-year-old patient, obtaining partial correction of the slippage (from 70 to 30 ). The authors of this study present an alternative to the classical techniques of subcapital realignment for the treatment of chronic and stable SCFE9 in patients with open physis, which allows adequate access to the hip joint, anatomical reduction of the slippage, and the theoretical advantage of rapid rehabilitation of the patient (Table 2). We found no studies in the literature describing an arthroscopic technique of subcapital realignment for the treatment of chronic and stable9 SCFE. To reduce the risk of avascular necrosis of the proximal femoral epiphysis, it is essential, when performing osteotomy of the femoral neck, to avoid advancing the osteotome in the direction of the posterosuperior retinaculum (which contains the terminal branches of the medial circumflex artery) or in the direction of the
Table 1. Step-by-Step Guide to Arthroscopic Subcapital Realignment in Chronic and Stable Slipped Capital Femoral Epiphysis
Table 2. Advantages and Risks of Arthroscopic Osteotomy vs Open Surgery for Treating Slipped Capital Femoral Epiphysis (SCFE)
1. Position the patient in the supine position on a regular radiolucent table 2. Position the portals with the aid of fluoroscopy 3. Use the anterolateral portal as the working portal (parallel to the physis) and the mid-anterior portal as the viewing portal 4. Use the extracapsular approach 5. Perform femoral osteochondroplasty, which allows resection of the bump deformity and better identification of the physis 6. Use a curved osteotome to make the osteotomy 7. After the osteotomy, perform femoral neck shortening and resection of the neoformed bone tissue in the posteromedial region of the femoral neck 8. Reduce the osteotomy (the hip is flexed, abducted, and internally rotated) 9. Check the final reduction by fluoroscopy in the anterior-posterior and frog-leg lateral view after stabilization of the epiphysis with 2 guidewires 10. Use a 6.5-mm partially threaded cannulated screw for percutaneous fixation
Advantages Small incision (vs wide exposure in the open technique) and possible surgical dislocation with the open technique Surgical morbidity is reduced Theoretical advantage of rapid rehabilitation of the patient Trochanteric complications that can occur with the surgical dislocation technique are avoided Correction of the deformity, instead of acting at complications (like other arthroscopic techniques for chronic and stable SCFE) Risks and disadvantages Fluid extravasation Iatrogenic articular instability with aggressive capsular resection Iatrogenic articular cartilage damage with noncareful instrumentation Nonvisualization of the posterior-superior retinaculum Impossibility of intra-articular assessment Bleeding after osteotomy may hinder visualization Can be technically challenging and should be performed by skilled arthroscopists
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Table 3. Pearls and Pitfalls Pearls Regular radiolucent table is recommended because of the need for greater mobility of the hip for transoperative maneuvers The anterolateral portal (working portal) should be placed in a location that allows access parallel to the physis For better identification of the physis and resection of the bump deformity, femoral osteochondroplasty of the femoral head-neck junction should be performed Shortening of the femoral neck and adequate resection of the posteromedial bone neoformation are essential to avoid excessive tension on the retinacular vessels when performing reduction The final epiphyseal reduction is checked by fluoroscopy in the anterior-posterior and frog-leg lateral view after stabilization of the epiphysis with 2 guidewires Pitfalls In severe slipped capital femoral epiphysis (SCFE), identification of the physis may be difficult without externally rotating the hip Advancing the osteotome posterosuperiorly or medially in the femoral neck can lead to posterosuperior retinaculum or inferior retinacular artery lesion The direct arthroscopic visualization of the epiphyseal reduction after osteotomy is not reliable and may be difficult due to bleeding, but is suggested by the presence of a step between the epiphysis and the femoral neck In chronic and stable SCFE >70 , adequate posteromedial bone resection cannot be possible to achieve arthroscopically due to its excessively posterior extension
3.
4.
5.
6. 7.
8.
9.
10.
inferior retinacular artery (which runs outside the retinacular tissue of the femoral neck inside Weitbrecht’s ligament). Likewise, shortening of the femoral neck and adequate resection of the posteromedial bone neoformation are essential to avoid excessive tension on the retinacular vessels (Table 3). Our current indications for this arthroscopic technique are for patients with chronic and stable SCFE, with 30 to 70 of slippage (epiphyseal-diaphyseal angle3) and with open physis. In our experience, in chronic and stable SCFE greater than 70 , adequate posteromedial bone resection can be difficult to achieve arthroscopically due to its excessively posterior extension.
References 1. Leunig M, Casillas MM, Hamlet M, et al. Slipped capital femoral epiphysis: Early mechanical damage to the acetabular cartilage by a prominent femoral metaphysis. Acta Orthop Scand 2000;71:370-375. 2. Sink EL, Zalz I, Heare T, Dayton M. Acetabular cartilage and labral damage observed during surgical hip
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12.
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dislocation for stable slipped capital femoral epiphysis. J Pediatr Orthop 2010;30:26-30. Southwick WO. Osteotomy through the lesser trochanter for slipped capital femoral epiphysis. J Bone Joint Surg Am 1967;49:807-835. Ziebarth K, Zilkens C, Spencer S, Leunig M, Ganz R, Kim Y. Capital realignment for moderate and severe SCFE using a modified Dunn procedure. Clin Orthop Relat Res 2009;467:704-716. Sucato DJ, De La Rocha A. High-grade SCFE: The role of surgical hip dislocation and reduction. J Pediatr Orthop 2014;34:S18-S24 (suppl 1). Sampson TG. Arthroscopic treatment of femoroacetabular impingement. Tech Orthop 2005;20:56-62. Loder RT, Skopelja EN. The epidemiology and demographics of slipped capital femoral epiphysis. ISRN Orthop 2011;2011:48652. Ganz R, Gill TJ, Gautier E, Ganz K, Krugel N, Berlemann U. 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;83:1119-1124. Loder RT, Richards BS, Shapiro PS, Reznick LR, Aronson DD. Acute slipped capital femoral epiphysis: The importance of physeal stability. J Bone Joint Surg Am 1993;75:1134-1140. Sankar WN, Vanderhave KL, Matheney T, HerreraSoto JA, Karlen JW. The modified Dunn procedure for unstable slipped capital femoral epiphysis: A multicenter perspective. J Bone Joint Surg Am 2013;95:585-591. Upasani VV, Matheney TH, Spencer SA, Kim YJ, Millis MD, Kasser JR. Complications after modified Dunn osteotomy for the treatment of adolescent slipped capital femoral epiphysis. J Pedriatr Orthop 2014;34: 661-667. Wylie JD, Beckmann JT, Maak TG, Aoki SK. Arthroscopic treatment of mild to moderate deformity after slipped capital femoral epiphysis: Intra-operative findings and functional outcomes. Arthroscopy 2015;31:247-253. Chen A, Youderian A, Watkins S, Gourineni P. Arthroscopic femoral neck osteoplasty in slipped capital femoral epiphysis. Arthroscopy 2014;30:1229-1234. Akkari M, Santili C, Braga SR, Polessello GC. Trapezoidal bony correction of the femoral neck in the treatment of severe acute-on-chronic slipped capital femoral epiphysis. Arthroscopy 2010;26:1485-1495. Dobashi ET, Blumetti FC, Pinto JP, Milani C, Ishida A. Artroscopia do quadril na epifisiólise grave [Hip arthroscopy in severe epiphysiolisis.]. Rev Bras Ortop 2010;45:5962 (suppl).
Abstract: Stable slipped capital femoral epiphysis (SCFE) is the most common disease in the adolescent hip, with an estimated frequency of 10.8 in every 100,000 individuals. Recent studies of the biomechanics of femoroacetabular impingement indicate that small anatomical deformities of the hip arising from SCFE can potentially cause permanent acetabular chondral damage. There is no consensus about the best treatment option, especially for cases of moderate or severe chronic slippage (Southwick classification). Some authors recommend treatment with fixation in situ, in the belief that remodeling of the residual deformity of the femoral neck during growth allows proper function of the hip joint. Others recommend correction at the site of the deformity (subcapital realignment), aiming for the anatomical reduction of the epiphysis and seeking to reduce the risk of chondral degeneration. The authors of this Technical Note present an alternative to the classical techniques of subcapital realignment for the treatment of moderate and severe chronic and stable SCFE, which allows adequate access to the hip joint and anatomical reduction of the slippage, besides having the theoretical advantage of rapid rehabilitation of the patient.
S
ome authors have suggested that small anatomical deformities arising from slipped capital femoral epiphysis (SCFE) can potentially cause permanent acetabular chondral damage, leading to early osteoarthrosis.1,2 In cases of chronic moderate or severe slippage (according to the Southwick classification3), one of the treatment possibilities is subcapital realignment, which allows correction at the site of the deformity, aiming for the anatomical reduction of the epiphysis and seeking to reduce the risk of subsequent chondral degeneration.4 The authors’ main criticism against the use of this technique is the risk of complications, such as avascular necrosis of the femoral head (AVN) and chondrolysis, which can occur in up to 28% of cases.5 However, the growing number of studies inthis area has enabled the minimization of
From the Hip Surgery Group, Hospital Ortopédico de Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil. The authors report the following potential conflicts of interest or sources of funding: B.D.R. receives support from Passo Fundo Orthopedic Hospital. Received September 20, 2016; accepted January 23, 2017. Address correspondence to Bruno Dutra Roos, M.D., Hip Surgery Group, Hospital Ortopédico de Passo Fundo, Rua 7 de Setembro, 817, Centro, Passo Fundo, Rio Grande do Sul, Brazil. E-mail: [email protected] Ó 2017 by the Arthroscopy Association of North America 2212-6287/16909/$36.00 http://dx.doi.org/10.1016/j.eats.2017.01.017
complications, with careful observation of technical details, such as preserving the vascular supply to the epiphysis during the procedure, being fundamental.4 The aim of this Technical Note is to describe an arthroscopic technique of subcapital realignment for the treatment of moderate and severe chronic and stable SCFE in patients with open physis. The work described here was carried out in accordance with the Code of Ethics of the World Medical Association (Declaration of Helsinki).
Surgical Technique The surgical technique for arthroscopic subcapital realignment in chronic and stable SCFE is shown in Video 1. General anesthesia with femoral nerve block is used. Physical examination of the hip is conducted with the patient under anesthesia to passively evaluate the bilateral range of movement. The patient is positioned in the supine position on a regular radiolucent table. The orthopaedic traction table is not used because of the need for greater mobility of the hip for the multiple transoperative maneuvers. The pelvis is slightly tilted to the contralateral side, and a radiotransparent pad is placed under the hemipelvis to be operated on (Fig 1). The anatomical references are marked using an appropriate pen. A vertical line is demarcated from the
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Fig 1. Preoperative radiographic images of a patient with left-sided chronic and stable slipped capital femoral epiphysis (SCFE). (A) An anterior posterior pelvic radiograph. The site of the slippage (growth plate) is shown with the white arrows. (B) A frog-leg lateral view radiograph showing an epiphyseal-diaphyseal angle of 54 . The site of the slippage is shown with the white arrows. The neoformed bone tissue in the posteromedial region of the femoral neck is shown with the yellow arrow. The bump deformity created by progression and chronification of the SCFE is shown with the red arrow. The dashed lines show the epiphysealdiaphyseal angle measure.
anterosuperior iliac spine to the center of the patella. The anterior, posterior, and proximal borders of the greater trochanter of the femur are also marked. Portals are positioned with the aid of fluoroscopy. The first is the mid-anterior portal, which is the camera portal. The second portal, the anterolateral portal, is placed in a location that allows access parallel to the physis, which is the working portal (Fig 2). The arthroscopic approach that we use for the subcapital realignment is the extracapsular one, which follows the access to the peripheral joint compartment, as described by Sampson.6 With the limb to be operated in the neutral position, and after establishing the arthroscopic portals, the
Fig 2. Preoperative photograph of a patient positioned for a left hip arthroscopy showing the portal placement. The mid-anterior portal (MAPd1) is the camera portal. The anterolateral portal (ALPd2) is placed in a location that allows access parallel to the physis (1 cm proximal and anterior to the original site), which is the working portal. The fluoroscopic image shows the projection of the mid-anterior (1) and anterolateral (2) portals.
anterior joint capsule and iliocapsular muscle are dissected, using radiofrequency (SERFAS, Stryker, Kalamazoo, MI) and a shaver (Stryker), until adequate exposure is achieved. T-capsulotomy is then performed on the femoral neck, which may be extended as necessary. Next, capsulectomy is performed, to achieve adequate exposure of the anterior region of the metaphysis and epiphysis of the proximal femur, in its mid-lateral extension (Fig 3). After sufficient exposure, femoral osteochondroplasty of the femoral head-neck junction is performed, which allows resection of the bump deformity created by progression and chronification of the SCFE, and better
Fig 3. View of a left hip through a 30 arthroscope in a midanterior portal. The extracapsular arthroscopic approach is used for exposure of the slipped capital femoral epiphysis. The arrows indicate the site of the slippage (growth plate) between the femoral head (FH) and the femoral neck (FN). (L, labrum.)
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Fig 4. View of a left hip through a 30 arthroscope in a mid-anterior portal. Femoral osteochondroplasty of the femoral head-neck junction is performed, which allows resection of the bump deformity created by progression and chronification of the slipped capital femoral epiphysis, and better identification of the physis. In more severe cases of slippage, external rotation of the limb may be necessary to expose the physis. (FH, femoral head; FN, femoral neck.)
identification of the physis (Fig 4). In more severe cases of slippage, external rotation of the limb may be necessary to expose the physis. The cupuliform osteotomy is performed 2 mm distal to the growth plate (to facilitate shortening of the femoral neck later) using a specific curved osteotome (Muzymed, Canoas, Brazil) guided by fluoroscopic assistance (Fig 5). Iatrogenic articular cartilage damage must be avoided.
Fig 5. View of a left hip through a 30 arthroscope in a midanterior portal. The cupuliform osteotomy is performed 2 mm distal to the growth plate (to facilitate shortening of the femoral neck later) using a specific curved osteotome inserted through the anterolateral portal. (CO, curved osteotome; P, physis.)
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Fig 6. View of a left hip through a 30 arthroscope in a midanterior portal. After the osteotomy, the hip is rotated externally with slight traction, to allow shortening of the femoral neck and resection of the growth plate using an arthroscopic curette and burr. After shortening, the hip is adducted to remove neoformed bone tissue in the posteromedial region of the femoral neck, which could impede the subsequent reduction. The red asterisk indicates the neoformed bone tissue, and the arrow the epiphysis. (AC, arthroscopic curette; FN, femoral neck.)
With the femoral neck separated from the epiphysis, the hip is rotated externally, with slight traction, to allow shortening of the femoral neck and resection of the growth plate using an arthroscopic curette (Muzymed) and burr (Stryker). After shortening, the hip is adducted to remove neoformed bone tissue in the posteromedial region of the femoral neck, which could
Fig 7. View of a left hip through a 30 arthroscope in a mid-anterior portal. Bleeding of the epiphysis can be observed after the osteotomy. (B, bleeding of the epiphysis; E, epiphysis; FN, femoral neck.)
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Fig 8. Transoperative frog-leg lateral fluoroscopic view of a left hip after the reduction of the epiphysis and stabilization with 2 guidewires. The dashed lines show a step between the epiphysis and the femoral neck, suggesting the reduction of the epiphysis.
impede the subsequent reduction (Fig 6). The amount of neck shortening and posteromedial bone resection is determined by trial and error through gentle reduction and fluoroscopic prechecking in the anterior-posterior view. Direct arthroscopic visualization of the reduction is not reliable and may be difficult due to bleeding, but is suggested by the presence of a step between the epiphysis and the femoral neck. The vascular viability of the epiphysis can be directly checked at any time, or by making a small perforation in it (Fig 7). The retinacular vessels are difficult to visualize. Finally, the hip is flexed, abducted, and internally rotated to reduce the epiphysis. The final reduction is checked by fluoroscopy in the anterior-posterior and frog-leg lateral view after stabilization of the epiphysis with 2 guidewires. A 6.5-mm partially threaded cannulated screw is used for percutaneous fixation (Figs 8-10). Active and passive joint movements are stimulated in the immediate postoperative period. Two crutches are used, and full weight bearing is allowed after 4 weeks (Table 1).
SCFE can potentially cause permanent acetabular chondral damage.4 Ganz et al.8 described the use of surgical dislocation of the hip when performing modified Dunn’s osteotomy (subcapital realignment) in the treatment of unstable9 and/or high-grade3 SCFE. According to the authors, this approach allows access to the hip, preserving the vascular supply to the epiphysis, with adequate resection of posteromedial bone neoformation of the femoral neck and satisfactory reduction of the epiphysis. Thus, the goal of restoring the anatomy of the proximal femur is achieved, using a technique that minimizes the risk of AVN.8 Leunig et al.1 showed labral and acetabular chondral lesions in 14 patients with unstable SCFE9 during subcapital realignment using the technique of surgical dislocation of the hip, and observed that these lesions occurred when the femoral metaphysis was at or beyond the epiphyseal line.1 Similarly, Sink et al.,2 using the same surgical technique, showed the presence of intra-articular lesions in 39 patients with SCFE, with 34 labral and 33 chondral injuries. Several authors have published the results of the use of the technique described by Ganz et al.,8 but with some complications. Sankar et al.,10 in a multicenter study that evaluated 27 patients with unstable SCFE,9 with a mean follow-up of 22.3 months, found 4 patients (15%) who needed revision surgery because of failure of the fixation, and 7 cases (26%) of AVN. The mean postoperative evolution for osteonecrosis was 21.4 weeks, and the patients who did not evolve with this complication presented significantly lower clinical pain scores, and higher postoperative satisfaction.10 Upasani et al.11 presented the results of 43 patients treated using this technique: 60% of the cases were patients with unstable SCFE9; 40% were considered acute; and 86% were classified as
Discussion SCFE is the most common pathology in the adolescent hip, with an estimated frequency of 10.8 in every 100,000 individuals.7 Recent studies of the biomechanics of femoroacetabular impingement indicate that small anatomical deformities of the hip arising from
Fig 9. Postoperative photograph of a patient after a left hip arthroscopy for subcapital realignment in chronic and stable slipped capital femoral epiphysis, showing the aspect of the wound closure. X indicates the portal sites and the asterisk the percutaneous fixation site.
ARTHROSCOPIC SUBCAPITAL REALIGNMENT IN SCFE
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Fig 10. Three-year and two-month postoperative radiographic images of a left-sided slipped capital femoral epiphysis. (A) An anterior posterior pelvic radiograph showing the postoperative correction of the slippage. (B) A frog-leg lateral view radiograph showing an epiphyseal-diaphyseal angle of 4 . The white arrow indicates the correction of the deformity. The dashed lines indicate the epiphyseal-diaphyseal angle measure.
severe slippage.3 Twenty-two complications were observed in 16 patients, with 15 revision surgeries due to AVN, failure of the fixation, and postoperative dislocation of the hip. Two patients needed indication for total hip arthroplasty.11 The most published studies on arthroscopic treatment of SCFE basically focus on the treatment of complications of the disease. Wylie et al.12 described femoral osteochondroplasty in 9 patients with residual deformity of SCFE after fixation in situ. Similarly, Chen et al.13 presented satisfactory results in 88% of patients after performing femoral osteochondroplasty on 37 patients. In acute on chronic cases, 2 authors reported trapezoidal osteotomy for arthroscopic treatment of SCFE. Akkari et al.14 presented the results of 5 cases, obtaining an average preoperative epiphyseal-diaphyseal angle3 of 82 , and an average postoperative angle of 14 , with 1 case evolving to AVN.14 Dobashi et al.15
presented a case report of severe acute on chronic SCFE in a 12-year-old patient, obtaining partial correction of the slippage (from 70 to 30 ). The authors of this study present an alternative to the classical techniques of subcapital realignment for the treatment of chronic and stable SCFE9 in patients with open physis, which allows adequate access to the hip joint, anatomical reduction of the slippage, and the theoretical advantage of rapid rehabilitation of the patient (Table 2). We found no studies in the literature describing an arthroscopic technique of subcapital realignment for the treatment of chronic and stable9 SCFE. To reduce the risk of avascular necrosis of the proximal femoral epiphysis, it is essential, when performing osteotomy of the femoral neck, to avoid advancing the osteotome in the direction of the posterosuperior retinaculum (which contains the terminal branches of the medial circumflex artery) or in the direction of the
Table 1. Step-by-Step Guide to Arthroscopic Subcapital Realignment in Chronic and Stable Slipped Capital Femoral Epiphysis
Table 2. Advantages and Risks of Arthroscopic Osteotomy vs Open Surgery for Treating Slipped Capital Femoral Epiphysis (SCFE)
1. Position the patient in the supine position on a regular radiolucent table 2. Position the portals with the aid of fluoroscopy 3. Use the anterolateral portal as the working portal (parallel to the physis) and the mid-anterior portal as the viewing portal 4. Use the extracapsular approach 5. Perform femoral osteochondroplasty, which allows resection of the bump deformity and better identification of the physis 6. Use a curved osteotome to make the osteotomy 7. After the osteotomy, perform femoral neck shortening and resection of the neoformed bone tissue in the posteromedial region of the femoral neck 8. Reduce the osteotomy (the hip is flexed, abducted, and internally rotated) 9. Check the final reduction by fluoroscopy in the anterior-posterior and frog-leg lateral view after stabilization of the epiphysis with 2 guidewires 10. Use a 6.5-mm partially threaded cannulated screw for percutaneous fixation
Advantages Small incision (vs wide exposure in the open technique) and possible surgical dislocation with the open technique Surgical morbidity is reduced Theoretical advantage of rapid rehabilitation of the patient Trochanteric complications that can occur with the surgical dislocation technique are avoided Correction of the deformity, instead of acting at complications (like other arthroscopic techniques for chronic and stable SCFE) Risks and disadvantages Fluid extravasation Iatrogenic articular instability with aggressive capsular resection Iatrogenic articular cartilage damage with noncareful instrumentation Nonvisualization of the posterior-superior retinaculum Impossibility of intra-articular assessment Bleeding after osteotomy may hinder visualization Can be technically challenging and should be performed by skilled arthroscopists
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Table 3. Pearls and Pitfalls Pearls Regular radiolucent table is recommended because of the need for greater mobility of the hip for transoperative maneuvers The anterolateral portal (working portal) should be placed in a location that allows access parallel to the physis For better identification of the physis and resection of the bump deformity, femoral osteochondroplasty of the femoral head-neck junction should be performed Shortening of the femoral neck and adequate resection of the posteromedial bone neoformation are essential to avoid excessive tension on the retinacular vessels when performing reduction The final epiphyseal reduction is checked by fluoroscopy in the anterior-posterior and frog-leg lateral view after stabilization of the epiphysis with 2 guidewires Pitfalls In severe slipped capital femoral epiphysis (SCFE), identification of the physis may be difficult without externally rotating the hip Advancing the osteotome posterosuperiorly or medially in the femoral neck can lead to posterosuperior retinaculum or inferior retinacular artery lesion The direct arthroscopic visualization of the epiphyseal reduction after osteotomy is not reliable and may be difficult due to bleeding, but is suggested by the presence of a step between the epiphysis and the femoral neck In chronic and stable SCFE >70 , adequate posteromedial bone resection cannot be possible to achieve arthroscopically due to its excessively posterior extension
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inferior retinacular artery (which runs outside the retinacular tissue of the femoral neck inside Weitbrecht’s ligament). Likewise, shortening of the femoral neck and adequate resection of the posteromedial bone neoformation are essential to avoid excessive tension on the retinacular vessels (Table 3). Our current indications for this arthroscopic technique are for patients with chronic and stable SCFE, with 30 to 70 of slippage (epiphyseal-diaphyseal angle3) and with open physis. In our experience, in chronic and stable SCFE greater than 70 , adequate posteromedial bone resection can be difficult to achieve arthroscopically due to its excessively posterior extension.
References 1. Leunig M, Casillas MM, Hamlet M, et al. Slipped capital femoral epiphysis: Early mechanical damage to the acetabular cartilage by a prominent femoral metaphysis. Acta Orthop Scand 2000;71:370-375. 2. Sink EL, Zalz I, Heare T, Dayton M. Acetabular cartilage and labral damage observed during surgical hip
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dislocation for stable slipped capital femoral epiphysis. J Pediatr Orthop 2010;30:26-30. Southwick WO. Osteotomy through the lesser trochanter for slipped capital femoral epiphysis. J Bone Joint Surg Am 1967;49:807-835. Ziebarth K, Zilkens C, Spencer S, Leunig M, Ganz R, Kim Y. Capital realignment for moderate and severe SCFE using a modified Dunn procedure. Clin Orthop Relat Res 2009;467:704-716. Sucato DJ, De La Rocha A. High-grade SCFE: The role of surgical hip dislocation and reduction. J Pediatr Orthop 2014;34:S18-S24 (suppl 1). Sampson TG. Arthroscopic treatment of femoroacetabular impingement. Tech Orthop 2005;20:56-62. Loder RT, Skopelja EN. The epidemiology and demographics of slipped capital femoral epiphysis. ISRN Orthop 2011;2011:48652. Ganz R, Gill TJ, Gautier E, Ganz K, Krugel N, Berlemann U. 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;83:1119-1124. Loder RT, Richards BS, Shapiro PS, Reznick LR, Aronson DD. Acute slipped capital femoral epiphysis: The importance of physeal stability. J Bone Joint Surg Am 1993;75:1134-1140. Sankar WN, Vanderhave KL, Matheney T, HerreraSoto JA, Karlen JW. The modified Dunn procedure for unstable slipped capital femoral epiphysis: A multicenter perspective. J Bone Joint Surg Am 2013;95:585-591. Upasani VV, Matheney TH, Spencer SA, Kim YJ, Millis MD, Kasser JR. Complications after modified Dunn osteotomy for the treatment of adolescent slipped capital femoral epiphysis. J Pedriatr Orthop 2014;34: 661-667. Wylie JD, Beckmann JT, Maak TG, Aoki SK. Arthroscopic treatment of mild to moderate deformity after slipped capital femoral epiphysis: Intra-operative findings and functional outcomes. Arthroscopy 2015;31:247-253. Chen A, Youderian A, Watkins S, Gourineni P. Arthroscopic femoral neck osteoplasty in slipped capital femoral epiphysis. Arthroscopy 2014;30:1229-1234. Akkari M, Santili C, Braga SR, Polessello GC. Trapezoidal bony correction of the femoral neck in the treatment of severe acute-on-chronic slipped capital femoral epiphysis. Arthroscopy 2010;26:1485-1495. Dobashi ET, Blumetti FC, Pinto JP, Milani C, Ishida A. Artroscopia do quadril na epifisiólise grave [Hip arthroscopy in severe epiphysiolisis.]. Rev Bras Ortop 2010;45:5962 (suppl).
