1. Division of Orthopedic Surgery, London Health Sciences Centre
Radiographic Analysis of Surgically Treated Flatfoot Deformity in Children with Cerebral Palsy
Alicia Kerrigan, MD, Waleed Kishta, MD, PhD, FRCSC, Kamary Coriolano DaSilva, PhD, Debra Bartley, MD, FRCSC, Timothy Carey, MD, FRCSC, Megan Cashin, MD, FRCSC
Division of Orthopedic Surgery, London Health Sciences Centre
Introduction
Results
Discussion
Demographics
17 patients met the inclusion criteria. The average age of selected patients was years (range years). This included 11 males and 6 females, all with spastic CP (12 diplegic, 5 hemiplegic). Of these patients, 11 underwent bilateral surgery and 6 underwent unilateral surgery (28 feet). GMFCS levels were identified, including 1 at GMFCS Level I, 10 at GMFCS Level II, and 6 at GMFCS Level III. These patients were followed with post-operative radiographs for a mean of 7.97 months (range months).
Pes planovalgus is a common foot deformity in children with CP, causing significant pain and functional limitation. Those that undergo surgical correction are at risk of future complications including stiffness, pain, and recurrence [8]. Lateral calcaneal lengthening osteotomy is known to preserve subtalar motion, but carries with it a 25% failure rate.
In looking at radiographic changes from surgery, we observed that 5 out of the 7 measurements used to study foot deformity changed significantly with surgical intervention. These results suggest that lateral calcaneal lengthening osteotomy provides a significant and positive improvement in overall foot deformity and alignment. This may indicate improvement in quality of life and functional status. To date, this is the first study to apply the validated foot deformity measurements to CP patients with flatfoot deformity who underwent surgical management.
As this was a retrospective radiographic review, a significant limitation exists in that clinical outcome was not measured for these patients. While CP is a condition that affects soft tissue and muscle spasticity, this study only took into account bony changes in alignment which further limits accurate assessment of foot deformity. Furthermore, this study is limited by the fact that several of these patients had non weight bearing post-operative radiographs, while standing radiographs were used for the validated measurements. Another limitation of this study is that there was no set standard for minimum time to follow-up. Many of these patients also had concurrent foot surgery, again possibly affecting the radiographic results.
While this study focused on lateral calcaneal lengthening, it would be meaningful apply these radiographic measurements to patients who have undergone subtalar arthrodesis. Future studies could also focus on the relationship between clinical outcome and radiographic outcome for these patients. Clinical outcome measures could include instrumented gait analysis, pain and quality of life scores, and shoe/orthotic tolerance.
Foot and ankle deformities are quoted to be as high as 93% in pediatric patients with cerebral palsy (CP) [1]. Pes planovalgus, or flatfoot, is the most common foot deformity in children with CP [2]. Many of these patients become functionally limited with shoe wear, orthotic wear, and ultimately ambulation.
The two most common surgical procedures for these patients are lateral calcaneal lengthening osteotomy and subtalar arthrodesis [3]. The goal of these operations is to correct the underlying deformity, obtain symptomatic relief, and prevent recurrence and progression. Lateral calcaneal lengthening osteotomy is often the preferred initial procedure, as it corrects the underlying deformity while preserving subtalar motion [4]. However, it has been reported to have a failure rate as high as 25%, with recurrence of the planovalgus deformity [5] . Many of these patients go on to require subtalar arthrodesis or other corrective surgeries [6].
Surgical decision making depends on both clinical and radiographic assessment. Weight-bearing radiographs of the foot and ankle are important contributors to surgical planning. Several radiographic measurements have been previously described and validated to quantify foot and ankle malalignment [7]. To date, these foot indices have not been applied to foot deformities in children with CP who have undergone surgical correction.
Figure 1: Example of Pre-Operative vs Post-Operative Standing Lateral Radiographs in CP Patient with Pes Planovalgus
Pre-operative
13 months post-operative
Table 1: Pre-operative and Post-operative Radiographic Measurements as Compared to Validated Values
Validated Mean Values (1 standard deviation (SD) [7]
Pre-Op Mean Values (1 SD)
Post-op Mean Values (1 SD)
Calcaneal Pitch Angle (˚)
17 ( 6.0)
3.68 (2.0)
15.51 (1.49)
Talocalcaneal Angle (˚)
49 ( 6.9)
42.15* (1.28)
43.85* (1.38)
Lateral Talo-First Metatarsal (MT) Angle (˚)
13 (7.5)
29.08 (2.8)
8.74 (2.6)
Naviculocuboid Overlap (%)
47 (13.8)
92.95* (2.48)
78.5* (4.54)
Medial-Lateral Column Ratio (%)
0.9 (0.1)
0.99* (0.01)
0.97* (0.01)
Talonavicular Coverage Angle (˚)
20 (9.8)
35.3* (3.7)
13.4* (2.9)
AP Talo-First MT Angle (˚)
10 (7.0)
25.85* (3.22)
11.35* (2.8)
Purpose
The objectives of this study are:
To analyze the radiographic changes seen on foot radiographs before and after a major surgical correction for foot deformity in children with CP
To assess whether or not, radiographically, these patients have improvement in their foot deformity post-operatively.
To investigate which of these parameters most accurately measure radiographic improvements after surgery.
Conclusion
*median value
In comparing the radiographs from before and after surgical intervention, statistically significant changes were seen in 5 out of the 7 validated measurements.
Lateral calcaneal lengthening osteotomy is a successful treatment option for patients with CP and flatfoot deformity. Radiographically, the deformity in these patients can be analyzed both pre-operatively and post-operatively by using radiographic measures including calcaneal pitch, lateral talo-first MT angle, naviculocuboid overlap, talonavicular coverage angle, and AP talo-first MT angle. While this is the first study to apply these validated measurements to CP patients with surgically treated flatfeet, future studies should focus on also integrating clinical outcome measures for a more holistic assessment of surgical success.
Methods
Degrees (˚)
A retrospective review was performed to identify patients aged 5-17 with a diagnosis of CP who underwent lateral calcaneal lengthening osteotomy for pes planovalgus between 2006 and 2015 at the Children’s Hospital at London Health Sciences Centre. Selected patients were required to have adequate pre-operative and post-operative anteroposterior (AP) and lateral foot radiographs with appropriate post-operative follow-up.
Exclusion criteria included patients with non-pathologic flexible flatfoot and patients with previous orthopaedic surgery on the same foot. Patients with inadequate follow-up (no radiographs after cast removal) and poor quality or missing radiographs were also excluded from the study.
Demographic data including gender, age, Gross Motor Function Classification System (GMFCS) level, and pattern of CP were collected. Pre-operative and post-operative radiographs were analyzed and measured on the same PACS computer system. 7 of the 10 previously validated radiographic measurements were chosen to be applied to this study for assessment of foot and ankle deformity (REF). This included calcaneal pitch angle and talocalcaneal angle for assessment of hindfoot alignment, naviculocuboid overlap and talonavicular coverage angle for assessment of midfoot alignment, and lateral talo-first metatarsal angle and AP talo-first metatarsal angle for assessment of forefoot alignment. Medial-lateral column ratio was also used to analyze the columns of the foot.
The database was analyzed using SPSS 23 and Microsoft Excel The alpha (α) level was set at p < A normality test was performed to observe whether all participants entering the study were normally distributed with regard to the severity of their deformity. Paired T-test was used to compare changes in radiographic measurements from before and after surgery. For those without normal distribution, Wilcoxon signed-rank test was used.
Figure 2(a): Calcaneal pitch angle before and after surgical intervention
Figure 2(b): Calcaneal Pitch Angle
References
Degrees (˚)
Kedem P, Scher DM. Foot deformities in children with cerebral palsy. Current Opinion in Pediatrics Feb;27(1):67-74.
Davids JR. The foot and ankle in cerebral palsy. The Orthopedic clinics of North America Oct;41(4):
Dogan A et al. A comparison of two different techniques in the surgical treatment of flexible pes planovalgus: calcaneal lengthening and extra-articular subtalar arthrodesis. Journal of Pediatric Orthopedics Jul;18(4):
Staheli LT. Practice of Paediatric Orthopaedics, Second Edition Philadelphia, PA: Lippincott Williams & Wilkins.
Andreacchio A, Orellana CA, Miller F, Bowen TR. Lateral column lengthening as treatment for planovalgus foot deformity in ambulatory children with spastic cerebral palsy. Journal of Pediatric Orthopaedics Jul-Aug;20(4):
Sees J, Miller F. Overview of foot deformity management in children with cerebral palsy. Journal of Children’s Orthopaedics Nov; 7(4):
Davids JR, Gibson W, Pugh L. Quantitative segmental analysis of weight-bearing radiographs of the foot and ankle for children: normal alignment. Journal of Pediatric Orthopaedics Nov-Dec;25(6):
Kadhim, M et al. Long-term outcome of planovalgus foot surgical correction in children with cerebral palsy. The Journal of Foot and Ankle Surgery Nov-Dec;52(6):
Figure 3(a): Lateral talo-first MT angle before and after surgical intervention
Figure 3(b): Lateral Talo-First MT Angle
Percent (%)
Figure 4(a): Naviculocuboid overlap before and after surgical intervention
Figure 4(b): Naviculocuboid Overlap
Degrees (˚)
Degrees (˚)
Figure 5(a): Talonavicular coverage angle before and after surgical intervention
Figure 6(a): AP talo-first MT angle before and after surgical intervention
Figure 5(b): Talonavicular Coverage Angle
Figure 6(b): AP Talo-First MT Angle