Severs skada – paradigmskifte gällande diagnostik och behandling?

Perhamre et al.
following year were also asked about. Three boys did not
answer, leaving n 5 41.
Pain was assessed with Borg’s CR-10 scale (Neely et al.,
1992). It is a VAS scale with anchors of verbal explanations
added to the numbers in the pain scale, and was used for
measuring pain associated with the two sports activities
chosen by each boy. Zero was absence of pain and 10 was
maximal pain. These self-assessed pain recordings were
made in direct relation to training and sport events, and
were answered with no influence from the investigators.
Activity level was measured with Engstro¨ m’s activity index
(Engstro¨ m, 2004), which includes five levels of physical
activity, A–E and assessed at start, at phase shifts and at the
end of week 26.
When soccer was one of the chosen activities (n 5 33), it was
always chosen as the first activity A, producing the highest
levels of heel pain. Running was the dominating activity
chosen as activity B (n 5 29). A majority of the boys (n 5 26)
had soccer as activity A, and running as activity B.
The study has been approved by the Regional Ethics Board
of Uppsala, Sweden (dnr 2004 M-377).
Neither the Public Sports Medicine Clinic nor the authors
have any relation to, profit or other benefits from the
companies that manufacture the products in this study.
Table 1. Baseline characteristics for the primary heel wedge group and
the primary heel cup group at study start
Primary heel Primary heel
wedge cohort cup cohort
Patients, numbers 24 20
Median age, years (range) 12 (10–14) 12 (9–14) P 5 0.844*
Median pain level (IQR) 4 (2.75) 5 (3.75) P 5 0.149*
Pain history, weeks (range) 8 (4–25) 12 (4–24) P 5 0.102*
*P-values computed using the two-tailed asymptotic Mann–Whitney
U-test.
IQR, interquartile range.
Table 2. The results of the first randomized 12 weeks of the study, using
a mixed ordinal logistic regression model to accommodate the longitudinal
design of the study (n 5 44)
Variable Odds ratio P-value 95% confidence interval
Activity A
Time 0.93 0.001 [0.89, 0.97]
Wedge 1 – –
No treatment 2.32 o0.001 [1.69, 3.19]
Cup 0.22 o0.001 [0.15, 0.34]
Initial pain 1.75 o0.001 [1.37, 2.23]
Activity B
Time 0.93 0.002 [0.89, 0.97]
Wedge 1 – –
No treatment 2.29 o0.001 [1.67, 3.16]
Cup 0.18 o0.001 [0.12, 0.27]
Initial pain 1.81 o0.001 [1.51, 2.17]
The wedge was chosen as base category (OR 1) for the treatment
variable, because our primary target was the comparison between the
wedge and the cup. The hypothesis was that the heel cup provided
significant better pain relief than the heel wedge. This regression analysis
included all measured data, and was corrected for time.
e44
Pain value (median), IQR
10.00
Borg CR-10
7.50
5.00
2.50
0.00
Cup
Wedge
Wedge
B1 I1 B2
Phase
I2 B3
Fig. 3. Separated cup and wedge group showing median
pain values and interquartile range (IQR) for the randomized
first part of the study and the corresponding two
baseline phases. Group I (white boxes) started with heel cup
(with crossover to heel wedge in the second part 9 group II
(gray boxes) started with heel wedge. The statistics includes
both activity A and B.
Statistics
In an ordinal mixed regression, the estimated pain was
modeled using initial pain, time and treatment as explanatory
variables. The effect of each explanatory variable was an odds
ratio (OR) representing the multiplicative effect of a change in
this variable. We categorized the self-reported pain (VAS,
score 0–10) into five levels (0–2, 3–4, 5–6, 7–8 and 9–10) and
modeled the pain level at each occasion using initial pain and
treatment as fixed effects, number of days since baseline 1–3 as
a fixed and random effect and patient as a random intercept.
Low odds scores translated into less pain and large odds into
more pain.
Modeling time since baseline 1–3 as both random and fixed
effect takes into account a possible healing effect over time
because this is a known property of the etiology of Sever’s
injury. The regression analyses were based on baseline phase 1,
intervention 1, baseline phase 2 and intervention 2 as these
were the phases included in the randomized part of the study.
The treatment variable had three levels where the wedge was
chosen as the base category as our primary target was the
comparison between the wedge and the cup. We analyzed the
two activities A and B separately. All regression analyses were
made using the statistical package gllamm (Rabe-Hesketh et
al., 2002; Stata, 2007) with adaptive quadrature in STATA/IC
10.0 (Stata Corp. LP, College Station, Texas, USA), (Table 2).
As a descriptive supplement to these regression analyses, a
diagram was added with pain medians and interquartile
ranges (IQR) for each phase. The pain relief for the wedge
and the cup was compared including both activities (Fig. 3).
Results
A total of 44 boys completed the study. There were
no significant differences in age, median pain level
Cup
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