Long-term results of surgical treatment of Slipped Capital Femoral Epiphysis in the Netherlands

Slipped Capital Femoral Epiphysis (SCFE) is the most common traumatic hip
disorder in adolescents, and it has a prevalence of 10.8 cases per 100,000
children1. SCFE is the loosening or separation, either partial or complete, of
the epiphysis of the femoral head. SCFE occurs in children 10 to 17 years, and
males account for 60% of the cases.
In the Netherlands this results into an incidence of 20-40 new cases per year,
a number that seems to be increasing every year with an increasing number of
obese children in our society. Murray et al found that the incidence of SCFE
increased two and a half times in the last two decades, from 3.78 per 100.000
children in 1981 to a 9.66 per 100.000 in 2000 in the UK.
Although the etiology of SCFE remains unclear, it has been shown that obesity,
the male gender, some systemic disorders and endocrine abnormalities are risk
factors for development of the condition.
The current classification of SCFE includes stable and unstable slip. A stable
SCFE is defined as one where the child is able to ambulate, with or without
crutches. An unstable SCFE is defined as one where the child cannot ambulate at
all. This classification system is predominantly based on patient history and
complaints and not on physical examination, radiographs or ultrasound.
Once SCFE is diagnosed, treatment is indicated to prevent progression of the
slip. For a stable SCFE; a single screw in situ fixation is still regarded the
gold standard. For unstable SCFE; urgent but gentle reduction and internal
fixation, with or without decompression is commonly advocated.2,12
In case of a mild to severe slip, open reduction and screw or pin fixation can
be considered to improve joint congruity and prevent for early onset secondary
osteoarthritis.


The treatment of SCFE has been extensively described by many authors. However,
few studies report the results of treatment at long-term follow-up. Wensaas et
al. evaluated sixty-six patients with a follow up of 38 years and reported a
correlation between the severity of the slip, the etiology of the slip (chronic
or acute) and the long term results using radiographic evaluation, the EQ-5D
questionnaire and the Harris Hip Score. Severe chronic and acute (bilateral)
slips have a poor long term outcome. Of all patients included in this study
with severe chronic and acute slips, 71% was given a total hip replacement due
to long term complications: 60% of the patient due to avasculair necrosis of
the femoral head, 20% of the patients due to Osteoarthritis and 20% of the
patients due to a low Harris Hip Score (69 points).
Hansson et al concluded that patients with mild slips have a better outcome on
long term then patients with a severe slip, but further long term studies are
required, especially on the choice between in situ pinning and corrective
osteomy for slips in excess of 50º.

Primary objective
The primary objective is to evaluate the long-term functional outcome and the
prevalence of osteoarthritis in patients surgically treated for SCFE between
1980-2002 in The Netherlands. We hypothesize a correlation between the severity
of slip and the functional outcome, radiographic results and quality of life.
The methods we use are four questionnaires: Harris Hip score, SF-36, Oxford Hip
score and HOOS, physical examination (range of motion examination and
impingement) and radiographs (anterior-posterior and lateral) of the hips.

Secondary objective
The secondary objective is to evaluate possible radiographic signs of
osteoarthritis. We expect to see a worse functional outcome and a lower quality
of life in patients with radiographic signs of osteoarthritis.

Tertiary objective
The third objective is to identify possible risk factors for a worse functional
outcome after in situ pinning, in order to be able to identify patients who
might benefit from a primary open reduction or even correction osteotomy

A list of treated patients has already been extracted from the LUMC and
JKZ/HAGA medical databases. All patient records have been checked, to see if
they are complete and still up-to-date.

Patients from the (AMC, ErasmusMC, LUMC, MUMC, UMCG, UMCN, VUMC, WKZ) will be
contacted by written request from their treating physician, inviting them to
visit the outpatient clinic. Non-responders will be contacted by telephone one
week after the letter is sent.
Patients will be asked to visit the outpatient clinic once; all of the measures
will be performed during this visit and will take about one hour.
JKZ patients have all been contacted and a complete physical and radiological
examination was already performed during clinical follow-up last year. The JKZ
patient population will be contacted through their treating physician in order
to complete the questionnaires.

Study Procedures

Radiographic evaluation:
Before the patient comes into the clinic (LUMC), we will request the pre- and
postoperative taken radiographs from the medical archives to measure the
southwick anterior-posterior angle. This has already been performed for all
patients in the LUMC and JKZ/HAGA group.

A standard anterior-posterior radiograph is performed; using the standard
positioning: The patient is supine, with the pelvis symmetrical for the
examination of the hip joint; the knees are flexed over a small sandbag and a
pressure pad is placed under the heels.
After the anterior-posterior positioning is taken, the radiographer confirms
the position and takes
the anterior -posterior and lateral radiographs using the standard technique.8
This has already been performed for all patients in the JKZ/HAGA group.

After the radiographs are taken, they will be used to measure the tangent line
on the anterior-posterior radiograph and to assess the Kellgren score on the
anterior-posterior and measure the Alfa angle on the lateral radiograph. All
radiographs will be scored by two blinded orthopaedic surgeons (one from the
LUMC one from the JKZ/HAGA)

Physical examination:
Range of motion examination refers to the distance and direction the hip joint
can move to its full potential. The examination will be an active and passive
range of motion.
The range of motion of the hip will be tested in 6 directions: flexion,
extension, abduction, adduction, medial rotation and lateral rotation
After the range of motion examination, the hip joint will be tested for
impingement through two provocative hip pain tests, one for the front of the
hip joint and one for the back.
When the impingement tests are finished, the trendelenburg sign and Duchenne
walk will be tested by watching the patient walking and standing on one foot.
Discrepancy is evaluated clinically. This has already been performed for all
patients in the JKZ/HAGA group.

Questionnaires:
Hip function and impairment will be evaluated using the HOOS, EQ5D, Harris Hip
score and SF-36 scores (Appendix 1). These questionnaires are subjective
quality of life scores, which are filled out by the patient alone. Some
patients were treated for bilateral SCFE. They need to fill an adjusted HOOS
questionnaire. The principal investigator will assist when needed.

HOOS:
The HOOS (Hip disability and Osteoarthritis Outcome Score) questionnaire has
proved to be valid for persons with hip disability with or without hip
osteoarthritis and with high demands of physical function. The HOOS
questionnaire includes 5 different parts: symptoms, pain, daily activities,
sports and quality of life, with a total of 40 questions. Each question can be
answered by filling in one of the five possible answers: from none to severe.

EQ5D:
EQ5D is a standardized questionnaire for use as a measure of health outcome for
patients whit or without arthritis in order to provide a simple generic measure
of health for clinical appraisal. The questionnaire includes 5 questions:
mobility, self care, daily activities, pain/symptoms and mental health. Each
question has 3 possible answers.

Harris Hip Score:
Hip function and impairment will be evaluated using the Harris Hip Score (HHS).
The HHS is a combined questionnaire including two parts: A questionnaire and an
observation list. The list is used as a diagnostic, prognostic or evaluating
list to measure the physical impairment of the hip joint and the quality of
life.
The HHS includes ten items with questions regarding last week. One item is
about pain, seven items are about functioning in daily life, one item is about
hip-deformities and one item is about the mobility of the hip. The maximum
score is 100 points. (Good/excellent: 90-100, Good: 80-90, moderate: 70-80,
insufficient: <70).

SF-36
The SF-36 is a multi-purpose, short-form health survey with 36 questions. It
yields an 8-scale profile of functional health and well-being scores as well as
psychometrically-based physical and mental health summary measures and a
preference-based health utility index. It is a generic measure, as opposed to
one that targets a specific age, disease, or treatment group.

Non-relating medical findings
Participating patients will be asked in advance if they want tot be informed on
unexpected medical findings not related to this study. If a unexpected medical
finding is found patients will be invited to the clinic to inform them of these
findings and their GP will be informed on this consult.

The European Union guidelines for radiation protection have been followed,
minimizing the radiation risk for our patients, exposing them to effective
doses of less than 0.1 mSv (adults). This category involves a risk (total
detriment from the radiation exposure) for normal subjects of the order of one
in a million or less.
This study will be performed within the values of the declaration of Helsinki
and will be handed to the Science committee of the LUMC Radiology Department
and METC for accreditation.