Journal of Children's Orthopaedics

The purpose of our study was to investigate the histological, histochemical and ultrastructural aspects of the proximal femoral growth plate in slipped capital femoral epiphysis (SCFE).

Eight core biopsies of the proximal femoral growth plate were performed during in situ epiphysiodesis in patients with SCFE that was at the pre-slipping stage in two cases and at the mild slipping stage (Southwick angle < 30°) in six cases. After fixation, the specimens were processed for either histological or histochemical or ultrastructural studies.

The proximal femoral growth plate was thicker than normal in the SCFE cases, and the 3:1 ratio between the thickness of the resting zone and the other zones of the plate was reversed. Chondrocytes of the proliferating, maturation, hypertrophic and degenerating zones were arranged in large clusters rather than in columns, which were separated by loose fibrillary septae that appeared moderately alcian blue positive and metachromatic. The collagen fibrils of the longitudinal septae were uniformly thin, measuring about 200 Å, whereas in the normal plate collagen fibrils were in the range of 300 to 1200 Å in thickness. Chondrocytes were elongated and smaller than normal, with a dark cytoplasm. In the degenerating zone, mineralisation of the longitudinal and transversal septae was scanty and enchondral ossification was impaired, with a few small osteoblasts forming thin bone trabeculae on the cartilage septae of the degenerating zone.

In SCFE, the proximal femoral growth plate undergoes several histological, histochemical and ultrastructural changes that precede slipping of the epiphysis since they are already present at a pre-slipping stage of the disease. The loss of solidity of the extracellular matrix and the disarrangement of the normal architecture of the physis very likely cause the consequent slipping of the proximal femoral epiphysis. SCFE aetiology remains unknown.

This article seeks to improve treatment outcomes in slipped capital femoral epiphysis (SCFE) by outlining advances in diagnosis, understanding of pathomechanics, and mechanically-based classification.

Review of clinical experience with SCFE at our high-volume centre, interaction with other clinical experts, and literature review has allowed a current perspective to be articulated

SCFE remains an important clinical problem, with late diagnosis still frequent. Improved understanding of the ubiquity of femoroacetabular impingement has guided current classification and treatment protocols

SCFE is an important clinical problem, with high historical rates of impaired hip function both in childhood and adulthood. Great opportunities exist for improved outcomes following earliest possible clinical diagnosis, modern imaging, and mechanically-based classification of involved hips to allow optimal treatment.

Slipped capital femoral epiphysis (SCFE) is a frequent disorder of the adolescent hip, which may lead to avascular necrosis (AVN) of the femoral head, chondrolysis and early osteoarthritis due to the post-slip deformity of the proximal femur. To warrant the best possible outcome for the affected (and contralateral) hip, early diagnosis and proper treatment are needed.

A review of the literature was undertaken to identify today's role of available imaging modalities in the management of SCFE.

This review outlines the relevancy of different imaging modalities such as radiography, ultrasound, CT, MRI and bone scintigraphy in the treatment of SCFE patients. While standard radiography is the first-choice imaging modality for patients with suspected SCFE, ultrasound and advanced imaging modalities may aid in surgical planning, diagnosis of complications such as AVN and treatment follow-up.

Management of moderately displaced slipped capital femoral epiphysis (SCFE) is debated, mostly because of the risks related to open reduction on one hand, and subsequent evolution toward femoroacetabular impingement (FAI) on the other.

All SCFE cases treated with in situ fixation (ISF) and a minimum of ten years of follow-up beyond skeletal maturity were analysed in a retrospective multicentre study. Coxometry parameters were measured. Long-term results of ISF were meanwhile analysed at our Institution.

A total of 222 patients were included. Patient reported outcome measurements were related to the severity of the initial slip. It suggested a 35.5° threshold for slip angle beyond which FAI was more frequent. Only slight remodelling at the head-neck junction is to be expected.

Based on these findings, it seems reasonable to perform ISF only in SCFE with a slip angle below 35°.

To describe and comment on the treatment of the slipped capital femoral epiphysis (SCFE) with pinning and to present the pros and cons of prophylactic pinning of the contralateral hip.

Pinning the SCFE aims to fix the epiphysis and prevent further slipping. Some devices allow for further growth and remodeling of the femoral neck post-operatively. This results in maintained femoral offset and probably reduced risk of femoroacetabular impingement. There are currently no long-term follow-up studies showing less complications or better function than after in situ fixation.

The contralateral hip can be managed by prophylactic pinning or close follow-up with repeated radiographic examinations. Which of the methods is best is still controversial due to different opinions on the risk of bilateral SCFE, the consequences of a later contralateral slip and the risks of prophylactic pinning. Although research supports prophylactic pinning the child and the family's preference is crucial.

Predictive factors for long-term outcome after in situ fixation for chronic slipped capital femoral epiphysis (SCFE) have so far not been systematically analysed. The aims of this study were to define predictors for long-term outcome and to assess the association between initial grade of slipping and post-slip deformities.

We studied 51 patients (60 hips) with chronic SCFE treated with in situ fixation. There were 31 males and 20 females with a mean age of 12.9 years. The mean follow-up was 39.0 years (21.1 to 56.8). Post-slip deformity was defined as abnormal alpha (a) angles in anteroposterior (AP) and lateral radiographs; AP angle of 74° and lateral angle of 63° were used as cutoffs between normal and abnormal α-angles. Harris hip score (HHS) less than 85 points was classified as a poor clinical outcome and osteoarthritis was a poor radiographic outcome.

The mean slip angle was 31.7° (12° to 77°). The mean AP α-angle was 67.4° (36° to 111°) and the mean lateral α-angle was 57.1° (22° to 104°). Post-slip deformities developed in almost one-third of hips with a mild degree of slipping and in about half the hips with more pronounced degrees of slipping. The long-term outcome was good in 40 hips (67%) and poor in 20 hips. A small AP α-angle was the only independent prognostic factor for a good combined clinical and radiographic outcome.

Post-slip deformity, defined as an abnormally high AP α-angle, is the most important prognostic factor for poor long-term clinical and radiographic outcome in chronic SCFE treated with in situ fixation.

Slipped capital femoral epiphysis (SCFE) is a deformity of the proximal femur secondary to widened and unstable physis. In stabilising the slip, gold standard treatments stop growth and involve premature physeal closure, which prevents the remodelling of the acquired deformity and creates a leg length discrepancy that may be significant in younger patients.

We measured the impact of placing threaded screws across the proximal femoral physis by measuring the centre-trochanteric distance (CTD) and articulo-trochanteric distance (ATD) in participants with or without prophylactic fixation. We then compared the mechanical performance of static (stainless and titanium cannulated Synthes screws) and potentially growing implants (Synthes SCFE screw and Pega Medical Free Gliding screw) in a validated synthetic bone model.

In the review of 30 non-fixed and 60 fixated hips over a mean follow-up of 1.9 years, we have noted a significant difference in pre/post CTD and ATD, as well as the change in CTD and ATD over time. In the biomechanical study, the newer implants allowing growth (Synthes SCFE screw and Pega Medical Free Gliding screw) were both shown to be at least non-inferior.

The primary deformity of a SCFE in itself alters hip mechanics. Also, as confirmed in this study, there is a secondary deformity that is created by static fixation and relative trochanteric overgrowth. To help remodel mild deformities and prevent secondary trochanteric overgrowth, growing implants seem to be non-inferior to the more standard means of fixation in static testing.

In situ pinning of slipped capital femoral epiphysis (SCFE) results in various degrees of deformity of the femoral head-neck junction. Repetitive trauma from cam-type femoroacetabular impingement (FAI) can lead to labral tears and injury to the articular cartilage causing loss of function. Arthroscopic osteoplasty is an alternative to open procedure and to Southwick/Imhäuser-type osteotomies in symptomatic selected cases.

The amount of bone to be resected has to be carefully planned pre-operatively. Only gentle traction is applied on a well-padded perineal support. A spherical burr is used to gradually resect the prominence. Intra-operative fluoroscopy is very useful when checking adequate reshaping of the head-neck junction is obtained.

Arthroscopy often reveals acetabular cartilage lesions, labrum hyperhemia and fraying which rarely require repair. Arthroscopic osteoplasty provides satisfactory pain relief and, to a lesser extent, restores hip internal rotation.

Arthroscopic osteoplasty is more technically and time-demanding in post SCFE than idiopathic FAI. It requires strong arthroscopic skills and experience in hip arthroscopy. It stands as a reasonable alternative to open procedure or flexion osteotomies in symptomatic FAI post mild to moderate SCFE. It provides pain relief and to a lesser extent restores internal rotation of the hip.

Based on improved knowledge of the vascular supply of the proximal femur, a safe surgical dislocation of the hip joint was established allowing direct insights to the pathomorphological malfunctioning of the joint. One insight was that slipped capital femoral epiphysis (SCFE) impingement leads to substantial damage of the chondrolabral rim area, even in the presence of minor slips. A further surgical development was the extended retinacular flap allowing for correction of the deformity with calculable risk for iatrogenic necrosis.

In 20 years of experience, a treatment concept for SCFE could be established which replaces classic pinning in situ and indirect correction of the deformity with subcapital re-alignment when the physis is still open, with true femoral neck osteotomy for hips with closed physis. Pinning in situ still has a place in minor slips but should be combined with open or arthroscopic recreation of an anterior metaphyseal waisting.

Loss of joint stability is a rare complication of anatomic re-alignment. It can be disease-related when the impingement has induced severe destruction of acetabular cartilage. It can be related to the surgical procedure, especially when the neck was excessively shortened and refixation of the trochanter was not advanced. Finally, in cases with severe and long-lasting deformity, the acetabulum may undergo adaptive flattening, being the cause of joint destabilisation with the correction of the deformity. Advancement of the greater trochanter and/or peri-acetabular osteotomy may be discussed to restabilise the joint.

Based on previous investigations on the vascular blood supply to the femoral head, a technique for anatomical reduction after slipped capital femoral epiphysis was developed. This technique is a modification of the original technique by Dunn using a retinacular soft-tissue flap. This allows the visual control of the epiphyseal vascular blood supply. We report the experience at the inventor's institution with a critical discussion of the available literature.

Using a trochanteric osteotomy for surgical dislocation of the hip, a retinacular soft tissue flap is created containing the deep branch of the medial femoral circumflex artery, the external rotators and the capsule. The femoral epiphysis can be mobilised safely and reduced on the femoral neck after resection of the almost constantly present reactive metaphyseal callus.

In our institution, the rate of avascular necrosis with 2% is comparably low to Dunn's original results. It is only present in cases where no bleeding was already evident before reduction of the epiphysis. The ten-year long-term results are favorable in these cases with a good functional result and only little progression of osteoarthritis. However, other authors have reported higher rates of avascular necrosis up to 24% in their initial experience.

In experienced hands using the correct meticulous surgical technique, the results are favorable regarding the rates of avascular necrosis, the functional outcome and the development of radiographic osteoarthritis – even in acute and severe cases. Avascular necrosis is rare but can be observed if there is no evidence of intra-operative femoral head perfusion before and after reduction of the epiphysis.

Slipped capital femoral epiphysis (SCFE) can result in a complex three-dimensional (3D) deformity of the proximal femur. A three-plane proximal femoral osteotomy (TPFO) has been described to improve hip mechanics. The purpose of this study was to evaluate the benefits of using 3D print technology to aid in surgical planning.

Fifteen children treated with TPFO for symptomatic proximal femoral deformity due to SCFE were included in this study. Ten patients were treated by a single surgeon with (model group, n = 5) or without (no-model group, n = 5) a 3D model for pre-operative planning, and compared with patients treated by two senior partners without the use of a model (senior group, n = 5) to evaluate for a learning curve. Peri-operative data including patient body mass index (BMI), surgical time and fluoroscopy time were recorded.

Children in all three groups had similar BMIs at the time of the TPFO. Post-operative radiographic parameters were equally improved in all three groups. On average, surgical time decreased by 45 minutes and 38 minutes, and fluoroscopy time decreased by 50% and 25%, in the model group compared with the no-model and senior groups, respectively.

Patient-specific 3D models aid in surgical planning for complex 3D orthopaedic deformities by enabling practice of osteotomies. Results suggest that 3D models may decrease surgical time and fluoroscopy time while allowing for similar deformity correction. These models may be especially useful to overcome steep learning curves for complex procedures or in trainee education through mock surgical procedures.

To survey the spectrum of surgical care in children with slipped capital femoral epiphysis (SCFE). This information is valuable in counselling the patient about the future treatment course.

Data for this study were obtained from the Pediatric Hospital Information System (PHIS) between 2004 and 2015. For all patients with an ICD9 diagnosis of 732.2, gender, ethnicity, hospital, medical record number, date of birth/admission/discharge, type of admission, length of stay, disposition and treatment(s) rendered were collected.

A total of 13 168 procedures were performed in 11 058 unique SCFE patients, or 1.2 procedures per patient. Primary procedures were those performed for the initial treatment of the SCFE and secondary procedures as reconstructive and salvage. The majority (11 693, 88.8%) were primary. There was significant variation in the ratio of primary and secondary procedures by institution. There was a decline in in situ fixation as the initial SCFE treatment with an increase in open reduction and internal fixation over the 12-year span. Similarly, there was a significant increase in the number of secondary procedures over time as well as complications and implant removal. There was no change over time in the diagnosis of avascular necrosis.

The average number of surgical procedures in patients was in the range of 1 to 6 and varied widely by hospital. Each physician should know his/her own hospital's data for the percentage of subsequent procedures so as to counsel the patient and family properly. The increasing number of complications over time may reflect the increasing number of more complex procedures.