Undercorrection of planovalgus deformity after calcaneal lengthening

in patients with cerebral palsy Byung Chae Cho, MD1; In Hyeok Lee, MD2; Chin Youb Chung, MD1; Ki Jeong Kim, MD4; Ju Seok Ryu, MD5; Kyoung Min Lee, MD1;

Soon Sun Kwon, PhD3; Gye Wang Lee, MD1; Myoung Ki Chung, MD1; Moon Seok Park, MD1

1 Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Gyeonggi, Korea. 2 Department of Orthopaedic Surgery, Sungkyunkwan University Samsung Changwon Hospital, Changwon, Korea.

3 Department of Mathematics, College of Natural Science, Ajou University, Gyeonggi, Korea 4 Department of Neurosurgery, Seoul National University Bundang Hospital, Gyeonggi, Korea

5 Department of Rehabilitation Medicine, Seoul National University Bundang Hospital, Gyeonggi, Korea.

OBJECTIVES

Calcaneal lengthening(CL) is one of the treatment options for

planovalgus deformity in patients with cerebral palsy.

However, the its indication still needs to be clarified according to the

functional status of cerebral palsy.

The aim of this study was to investigate the radiographic outcome after

CL in patients with CP and to evaluate the risk factors causing

undercorrection of planovalgus deformities.

METHODS

We included consecutive patients with CP who underwent calcaneal

lengthening for planovalgus deformity, were followed for more than two

years, and had pre- and postoperative weight-bearing anteroposterior

and lateral foot radiographs.

Six radiographic indices were used to assess the radiographic outcome.

The patient age, sex, and GMFCS level were evaluated as possible risk

factors, and we controlled for the interaction of potentially confounding

variables using multivariate analysis.

RESULTS

A total of 44 patients (77 feet) were included in this study. Mean age at the time

of surgery was 10.5 ± 4.0 years, and the mean follow-up was 5.1 ± 2.2 years.

Patients with GMFCS III/IV was achieved less correction than those with

GMFCS I/II in the AP talus-first metatarsal angle (p = 0.001), lateral

talocalcaneal angle (p = 0.028) and lateral talus-first metatarsal angle (p

< 0.001)(Table 1).

The rate of undercorrection in the GMFCS III/IV group was 1.6 times higher

than that in the GMFCS I/II group in the AP talus-first metatarsal angle (OR: 1.6;

95% CI: 1.2-2.0; p < 0.001), and 1.6 times higher in the lateral talus-first

metatarsal angle (OR:1.6; 95% CI: 1.3-1.9; p < 0.001) (Table 2).

CONCLUSIONS

We found calcaneal lengthening to be an effective procedure for the correction

of planovalgus foot deformities in GMFCS I/II patients with cerebral

palsy(Figure 1).

However, calcaneal lengthening alone results in a high undercorrection rate in

GMFCS III/IV patients with planovalgus deformities(Figure 2).

We believe that additional medial column stabilization procedures or

alternative procedures should be considered to correct the deformity and to

maintain the correction achieved.

AP Talus-First

Metatarsal Angle

Calcaneal pitch

angle

Lateral

Talocalcaneal

angle

Lateral Talus-First

Metatarsal Angle

Estimatio

n

(95% CI)

(deg)

p value

Estimatio

n

(95% CI)

(deg)

p value

Estimatio

n

(95% CI)

(deg)

p value

Estimatio

n

(95% CI)

(deg)

p value

Intercept -16.9 - 4.6 - -16.8 - -

Age 0.6 (-0.1

to 1.2) 0.079

-0.2 (-0.7

to 0.3) 0.437

0.7 (0.2 to

1.2) 0.004

1.2 (0.5 to

1.9) <0.001

Sex (male) -1.1 (-6.6

to 4.2) 0.662

3.8 (-0.2

to 7.9) 0.061

-1.0 (-4.8

to 2.8) 0.606

-5.1 (-10.9

to 0.6) 0.077

Side 0.4 1.8 -1.3 -1.4

GMFCS

Level I/II

(reference) - - - - - - - -

Level III/IV 9.1 (3.8 to

14.5) 0.001

-2.0 (-6.0

to 2.0) 0.328

4.3 (0.5 to

8.1) 0.028

10.3 (4.6

to 16.0) <0.001

Table 1. Estimation of the amount of correction

AP Talus-First

Metatarsal Angle

Calcaneal pitch

angle

Lateral

Talocalcaneal

angle

Lateral Talus-First

Metatarsal Angle

Adjusted

ORs (95%

CI)

p value

Adjusted

ORs (95%

CI)

p value

Adjusted

ORs (95%

CI)

p value

Adjusted

ORs (95%

CI)

p value

Age 1.0 (1.0 to

1.0) 0.688

1.0 (0.9 to

1.0) 0.003

1.0 (1.0 to

1.0) 0.271

1.0 (1.0 to

1.0) 0.158

Sex (male) 1.0 (0.8 to

1.2) 0.807

0.9 (0.7 to

1.1) 0.229

1.0 (0.8 to

1.2) 0.982

1.1 (0.9 to

1.4) 0.363

Side 0.4 1.8 -1.3 -1.4

GMFCS

Level I/II

(reference) - - - - - - - -

Level III/IV 1.6 (1.2 to

2.0) <0.001

1.3 (1.1 to

1.6) 0.009

1.2 (1.0 to

1.5) 0.105

1.6 (1.3 to

1.9) <0.001

Table 2. Potential risk factor for undercorrection

*AP = anteroposterior, OR = odds ratio, CI = confidence interval

Figure 1. In patients with GMFCS level I/II, the rates of complete correction in

AP talus-first metatarsal angle and lateral talus-first metatarsal angle after

calcaneal lengthening were both 62.8%.

Figure 1

Figure 2. By contrast, in the GMFCS III/IV group these rates were 20.6% in AP

talus-first metatarsal angle and 14.7% in lateral talus-first metatarsal angle.

Figure 2