Slipped Capital Femoral Epiphysis (SCFE)
The incidence of SCFE is approximately 2 in 100,000 live births and primarily affects children between the ages of 6 and 18, with the highest occurrence between 10 and 16 years old. In most cases, the causes of SCFE are unknown. However, some authors have identified risk factors and associated conditions. These include improper dietary habits, low physical activity, obesity, as well as hormonal disorders or genetic syndromes.
Hip Pain in Children, Is it the Only Symptom of Slipped Capital Femoral Epiphysis?
Slipped Capital Femoral Epiphysis primarily affects individuals during the adolescent growth spurt. Initially, patients experience mild pain in the hip region, which may radiate to the thigh or knee. There is often a misleading symptom of inner knee pain, caused by the shared innervation of the hip and knee joints by the obturator nerve. This knee pain can often lead to misdiagnosis and delay in the proper diagnosis.
Individuals with SCFE often have difficulty in abducting their limb and may exhibit a tendency to limp. As the condition progresses, which involves the displacement of the femoral head in relation to the neck, characteristic symptoms of the disorder appear. These include relative limb shortening and the Drehmann sign (flexion of the hip joint occurs with simultaneous abduction and external rotation).
Diagnosis and Treatment of SCFE
To diagnose Slipped Capital Femoral Epiphysis, X-ray examinations in anteroposterior and axial projections are necessary. The degree of displacement is assessed based on the X-ray images using a 3-point scale:
- Chronic slip
- Acute slip
- Acute slip superimposed on chronic slip (“acute-on-chronic” – increased pain on top of preexisting chronic pain)
In 1993, Loder introduced an additional classification for SCFE:
- Stable slip, allowing weight-bearing with or without crutches
- Unstable slip, characterized by severe pain that prevents weight-bearing
Surgical intervention is the preferred treatment for SCFE. At the Paley European Institute, for patients with a lesser degree of femoral head displacement, stabilization of the slip is performed using specialized cannulated screws, but only if there has not been partial or complete dislocation of the joint. There is no one-size-fits-all method in this case, as the approach should be individualized for each patient based on the degree of slip.
Individualized Surgical Approach in SCFE
The choice of an appropriate surgical method depends on the degree of slip and the individual characteristics of the patient. The goal of surgical treatment is to restore bone stability, anatomical alignment, and prevent further progression of the slip. These operations aim to minimize the risk of complications and improve long-term functional outcomes of the hip joint in patients with SCFE.
For pre-slip conditions and mild slips (0-30°), pinning in situ with Kirschner wires and cannulated screws is recommended for femoral head and neck stabilization.
For moderate slips (30°-60°), in situ femoral head and neck stabilization, combined with subtrochanteric or intertrochanteric osteotomy, is performed.
It is important to note that stabilization is maintained until the completion of growth within the femoral head, which occurs with the fusion of the growth plate. Sometimes, hardware exchange is necessary due to the child’s growth, as the pins or screws become too short during their development.
In cases of severe slips (above 60°), open reduction of the dislocated femoral head using the modified Dunn method is performed. This involves surgically safe dislocation of the hip joint (safe surgical hip dislocation – SSHD) without disturbing the muscles around the hip joint. Unlike the closed method (pinning in situ), this procedure provides close to 100% chances of returning to full pre-injury function.
In cases of significant femoral head displacement, failure to achieve proper reduction and relying solely on bone stabilization with screws significantly increases the likelihood of secondary deformities, the development of degenerative hip joint disease in the future, pain, and joint mobility disorders.
For chronic and fixed changes, consideration is given to joint reconstruction through femoral head reduction osteotomy (FHRO), which involves cartilage plasticity of the femoral head following surgical safe dislocation of the hip joint (SSHD).
It is important to remember that a properly performed surgical intervention requires appropriate physiotherapy. Only then do patients have the greatest chance of regaining functionality. Our experience shows that this is possible within approximately 6 weeks after surgery.
The goals of treating Slipped Capital Femoral Epiphysis (SCFE) are centered around achieving several important objectives. Firstly, the aim is to achieve stabilization of the femoral head, preventing further slippage of the bone. Another goal is to stimulate early closure of the growth plate, aiding in the proper bone development. Additionally, treatment aims to restore anatomical alignment to regain normal joint function and prevent early degenerative changes. By accomplishing these goals, the aim is to minimize long-term complications and provide the best possible outcomes in hip joint functioning.
Development of surgical treatment methods – a historical overview and the modified Dunn method
The discussion regarding the surgical treatment of Slipped Capital Femoral Epiphysis (SCFE) has been ongoing for many years. In terms of surgical methods, the approach that allows for control of the blood supply to the femoral head and anatomical restoration of the epiphysis is considered the best solution, providing optimal conditions for long-term hip joint functioning.
In the mid-20th century, an effective method was described, which involved subcapital anatomical reorientation of the epiphysis through surgical dissection and the use of a soft tissue flap. This procedure aimed to restore the proper anatomy of the hip joint by repositioning the epiphysis in relation to the femoral neck. However, it was associated with avascular necrosis (AVN) rates of up to 54%.
In 1964, Dunn modified the aforementioned method for repairing SCFE. His technique involved making an incision around the trochanter and approaching the hip joint from the posterior and lateral aspects. The risk of avascular necrosis (AVN) was minimized to 4%. Dunn observed that in most patients, a pseudarthrosis forms in the posterior part of the femoral neck. It is not visible from the front and cannot be corrected.
The modified Dunn method has been widely adopted and has significantly improved the outcomes of surgical treatment for SCFE. It represents an important milestone in the development of surgical techniques for this condition.
Since the epiphysis is smaller in slipped capital femoral epiphysis (SCFE), the blood vessels, which are typically shorter in this condition, are stretched and can be damaged. This can lead to a high risk of avascular necrosis (AVN) of the femoral head in these procedures. Dunn emphasized the importance of meticulous vascular preparation by removing the recently formed false joint and slightly shortening the femoral neck to ensure proper blood supply to the femoral head.
In 1991, Carney and other researchers published their studies on various treatment methods for SCFE. They concluded that “pinning in situ” stabilization is the least risky in terms of AVN and has become the preferred approach even in severe cases of SCFE. However, there is an increasing number of cases where patients experience functional problems and earlier onset of hip osteoarthritis after undergoing “in situ” stabilization (between the femur and the acetabulum).
As a result of extensive research over the past 20 years focusing on arterial blood supply to the femoral head, a new surgical technique for reducing the femoral head has been developed, characterized by a very low risk of AVN. A method for consistently creating a vascularized flap has also been devised. With precise access to the integrity of the retinacular vessels in relation to the femoral head, it is now possible to fully surgically access the femoral neck and the slipped epiphysis. This new method ensures more efficient blood circulation in the femoral head compared to the traditional closed reduction procedure, while minimizing the risk of retinacular vessel damage.
It is possible to anatomically adapt the displaced femoral head while regulating the blood supply to the retinacular vessels using the modified Dunn method with the use of a retinacular soft tissue flap. Even in cases of acute and severe SCFE, when the procedure is performed by an experienced surgical team using precise techniques, favorable outcomes have been observed in terms of minimizing the risk of joint inflammation on X-ray images and AVN indicators. If the blood supply to the femoral head is not assessed during the reduction of the epiphysis, avascular necrosis without infection can occur.
The PEI team is one of the few in the world that performs the above technique and has vast experience in it. Take a look at the stories of our patients (Janek’s story) – who underwent surgical treatment for slipped capital femoral epiphysis using the open Dunn technique for reducing the femoral head.
- Slipped Capital Femoral Epiphysis (SCFE)
- The modified Dunn procedure for slipped capital femoral epiphysis: the Bernese experience, Journal of children’s orthopaedics, 2017 Apr; 11(2): 138–146.