Slipped capital femoral epiphysis

Clinical History

13-year-old female patient with a history of intermittent right-sided hip pain for the past 6 months presented to the emergency department after a fall from stairs followed by pain in the right hip. A fracture was suspected and she was referred for right hip/pelvis radiography.

Imaging Findings

AP (Fig. 1) and frog-leg (Fig. 2) views of pelvis were taken. AP view shows a slightly widened femoral epiphysis on the right side which is very apparent on frog-leg/Lauenstein view as a medio-posterior slippage of the right femoral epiphysis.

Post-operative AP radiograph (Fig. 3) shows surgical fixation of the right femoral epiphysis to its normal position with screw placement.

Discussion

Background:

Slipped capital femoral epiphysis (SCFE), a nontraumatic fracture through growth plate with anterior displacement of the femoral neck metaphysis relative to the epiphysis, is the most common hip abnormality in adolescents with frequent lifelong sequelae, having a prevalence of 2 cases per 100, 000 children which predominantly affects boys in the age group of 8-15 years, suggesting association with growth spurt and changing orientation of physis from horizontal to oblique. [1] Other factors such as genetics, biomechanical forces, metabolic disorders are postulated to cause slippage by pathological distubances in physis [3]

Clinical perspective:

Frequently presenting symptoms are painful hip or knee or limp which can be misdiagnosed as muscle strain, Osgood-Schlatter disease or flat feet and delay in diagnosis often leads to poor long-term results due to progression in slip severity [1, 3]

Imaging perspective:

Anterior, lateral and frog leg lateral radiographs with gonad protection are performed, which shows widening of the physis with or without demineralization in pre-slip phase. [1] Acute slip is seen as a fracture without sclerosis at the physis, in contrast to acute-on-chronic slip, which shows sclerosis and irregularity around the widened physis with associated remodelling in the femoral neck. Radiologically mild to severe displacement depends on the degree of femoral head displacement compared to the diameter of metaphysis. Line of Klein and metaphyseal blanch sign can help make the diagnosis. [1] USG and MR can also aid in reaching the diagnosis.

Outcome:

Early complication are slip progression, hardware loosening, chondrolysis. AVN (avascular necrosis) is associated with advanced unstable slippage, extensive manipulation, delayed surgery, anterior or many pin placement, subcapital and neck osteotomies. Late complications are 'pistol grip' deformity or CAM-type femoroacetabular impingement leading to articular chondral damage, osteoarthritis, limb length discrepancy [2, 4]

Treatment:

Prevention of early osteoarthritis, avascular necrosis and additional displacement along with achieving optimal functional outcome are the primary goal of treatment which can be achieved by stabilization of the epiphysis with in-situ pin or screw placement. [1, 2, 3] Additional femoral head-neck osteochondroplasty performed in mild SCFE is thought to prevent femoroacetabular impingement too, but further study is needed to determine whether it is justified to prevent articular damage. [2, 3, 4] In moderate to severe SCFE, intertrochanteric or subtrochanteric osteotomies are advised due to excellent results and low occurrence of osteoarthritis and AVN. [1, 3]

Prophylactic pinning of contralateral hip is advocated by some authors but others prefer to closely monitor it for 1-2 years instead. [1, 3]


Teaching points:

It is important to differentiate SCFE from Salter-Harris fracture as treatment is different.

Differential Diagnosis List

Final Diagnosis

Right-sided slipped capital femoral epiphysis

URL:	https://www.eurorad.org/case/13704
DOI:	10.1594/EURORAD/CASE.13704
ISSN:	1563-4086