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Guided growth for the Treatment of Infantile Blount's disease: Is it a viable option?
Journal of Orthopaedics 20 (2020) 41–45
Contents lists available at ScienceDirect
Journal of Orthopaedics journal homepage: www.elsevier.com/locate/jor
Original Article
Guided growth for the Treatment of Infantile Blount's disease: Is it a viable option?☆
T
B. Gage Griswolda,∗, K. Aaron Shawa,b, Harrison Houstonc, Styles Bertranda, David Cearleya a
Department of Orthopaedic Surgery, Children's Hospital of Georgia at Augusta University, Augusta, GA, USA Department of Orthopaedic Surgery, Dwight D. Eisenhower Army Medical Center, Fort Gordon, GA, USA c Medical College of Georgia, Augusta University, Augusta, GA, USA b
A R T I C LE I N FO
A B S T R A C T
Keywords: Infantile Blount's Guided growth Temporary hemiepiphysiodesis Knee Genu varum
Introduction: Guided growth with temporary hemiepiphysiodesis has gained interest as a less invasive means for the treatment of coronal plane lower extremity deformities as well as leg length discrepancies. Its application to infantile Blount's disease has been less reported. The object of this study was to identify predictive factors of guided growth for treatment of infantile Blount's. Methods: A retrospective review was performed of children undergoing guided growth for the treatment of infantile Blount's disease over an eight-year period. Inclusion criteria included treatment with THE for infantile Blount's disease. Clinical information, preoperative Langenskiold classification, and intra-operative and postoperative data. Preoperative variables were used to identify risk factors for speed of correction and the need for subsequent surgery. Results: A total of 11 patients, 17 extremities, meeting inclusionary criteria. Preoperatively, 7 extremities were classified as Langenskiold stage ≥3, with 12 being classified as stage ≤2. Overall, the Drennan's angle improved from 18.3° to 0.3° by final follow-up at an average of 4.31 years. Eight extremities demonstrated deformity recurrence/persistence (stage ≤2:33% vs stage ≥3: 100%), requiring 24 reoperations. Children with Langenskiold stage ≥3 demonstrated a significantly higher rate of reoperation. Conclusion: Guided growth is a viable treatment option for Infantile Blount's disease presenting with Langenskiold stage ≤2 disease at treatment initiation. The treatment course can expect a 33% rate of recurrent deformity, treated successfully with repeat THE. No child stage ≤2 required corrective osteotomy. Caution should be used when considering guided growth for children presenting with Langenskiold stage ≥3.
1. Introduction Infantile Blount's is a result of spontaneous deceleration of the posteromedial growth plate of the proximal tibial physis resulting in a multi-dimensional lower extremity deformity due to sloping of the epiphysis.1 Although the precise etiology of infantile Blount’ disease is unknown, obesity has the strongest correlation with its development. In general, there is a lack of consensus regarding the optimal treatment approach for this condition. Bracing is a controversial treatment method, that has varied results demonstrated in the literature depending upon the severity of disease, age at presentation, and presence of bilateral disease.2–5 A variety of surgical interventions are commonly used for
progressive deformity or disease that fails to respond to bracing. The aim of surgical treatment is to restore a congruent joint surface, a task that can be achieved acutely, or gradually. Classically, the recommended treatment approach has been to perform an acute corrective osteotomy to correct the angular deformity and level the articular surface.6–8 A newer approach with guided growth modulation has gained interest. Guided growth can be performed with either tension band plating or screws, intending to temporarily arresting the normal physis, in the lateral tibial physis in the case of infantile Blount's disease, to allow preferential growth from the diseased physis, and thus angular correction. Although growth modulation with temporary hemiepiphysiodesis (THE) has been shown to be highly effective for the treatment of
☆ The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the Department of Defense or US Government. The authors are employees of the US government. This work was prepared as part of their official duties and, as such there is no copyright to be transferred. ∗ Corresponding author. Department of Orthopaedic Surgery, 1120 15 th Street, BA-3300, Augusta, GA, 30912, USA. E-mail address: [email protected] (B.G. Griswold).
https://doi.org/10.1016/j.jor.2020.01.007 Received 21 November 2019; Accepted 6 January 2020 Available online 10 January 2020 0972-978X/ Published by Elsevier B.V. on behalf of Professor P K Surendran Memorial Education Foundation.
Journal of Orthopaedics 20 (2020) 41–45
B.G. Griswold, et al.
coronal plane deformities with low complications rates,9 little research has focused on its particular application for the treatment of infantile Blount's disease.10,11 The purpose of this study was to investigate the effect of guided growth, using THE, for the treatment of infantile Blount's disease. We hypothesized that younger patients with less severe deformity, defined according to the Langenskiold classification system, would have higher rates of treatment success.
Table 1 Summary of patient demographic information. Variables
2. Materials and methods After obtaining institutional review board approval, records for all pediatric patients who underwent THE with cannulated screws and trans-epiphyseal plate for infantile Blount's disease performed over an eight-year period (2008–2016) were retrospectively reviewed. Inclusion criteria included treatment with temporary hemi-epiphysiodesis, using a tension band plating technique, for isolated Infantile Blount's disease with a minimum of 1-year radiographic follow-up. Identification was performed using a combination of ICD-9 (732.4), ICD-10 (M21.16 and M92.5) codes representing the diagnosis and infantile Blount's disease and common procedural terminology codes 27485, 27477, and 27475, representing possible options for THE. Patients were excluded from study inclusion if they had an underlying diagnosis affecting the musculoskeletal system, performed for a diagnosis other than infantile Blount's disease, underwent treatment other than THE, were treated with technique other than tension band plating, or had < 1-year radiographic follow-up. Clinical information was recorded, including height, weight, body mass index (calculated as a percentile for patient age), race, the age at which the patient underwent surgical correction. Complications were recorded including the development of wound dehiscence, surgical site infections, recurrent deformity, physeal bar formation (diagnosised with the use of Magnetic resonance imaging), hardware complication, and overcorrection. Treatment success was defined as ability to achieve deformity correction with THE without development of physeal bar and/or need for corrective osteotomy. Radiographic information was recorded. Pre-operative Langenskiold classification was determined independently by 2 pediatric orthopaedic surgeons and one pediatric orthopaedic fellow. In the event of discrepancy, imaging studies were collectively reviewed and a consensus classification was determined. Radiographic measurements were recorded at initial treatment and final follow-up, including metadiaphyseal angle (Drennan) angle, lateral distal femoral angle (LDFA), and mechanical axis (MA). Additionally, the presence of femoral physeal abnormalities were recorded. The degree of correction was calculated by subtracting the Drennan angle, LDFA, and MA at final follow-up from the preoperative measurement. Duration of treatment was recorded, defined as the time from initial surgery until hardware removal. The rate of recurrent deformity was recorded, defined as the development of recurrent varus alignment after initial successful correction. Time until recurrence was calculated as the time between hardware removal and the date that recurrent deformity was initially diagnosed. For extremities that did not undergo initial correction, these were defined as persistent deformity and were excluded from this calculation.
Total Limb Cohort
Langenskiold Classification ≤2
Langenskiold Classification ≥3
(n = 17)
(n = 12)
(n = 5)
Mean ± SD
Mean ± SD
Mean ± SD
Age at time of treatment (y) Body Mass Index
3.2 ± 1.4
2.7 ± 0.465
4.36 ± 2.16
93.1 ± 14.5
90.2 ± 16.6
99.99 ± 0
Race
n
n
n
Black White Hispanic Multiple Sex Male Female
9 4 2 2
5 4 1 2
4 0 1 0
6 11
6 6
0 5
Drennan angle, and BMI percentile for age could significantly predict Speed of Correction.
3. Results A total of 57 patients were identified for study inclusions. From these children, 43 were excluded (27 patients with physiologic tibia vara, 8 patients with internal tibial torsion, 4 with tibia vara with associated genetic condition (Achondroplasia (2), Lowe Syndrome, Spondylometaphyseal Dysplasia), 2 were as a result from intrauterine packing, and 1 underwent hemiepiphyseiodesis for a leg length discrepancy. Three additional children were excluded due to a lack of follow-up. This left a total of 11 patients, 17 extremities, meeting inclusionary criteria (average 3.25 years, average BMI for age 93.4, 64.7% female, 63.6% bilateral). Demographic information is summarized in Table 1. Two patients had undergone bracing prior to operative intervention. Associated rotational abnormalities were present in 4 patients with 3 having internal tibial torsion and a fourth have internal tibial torsion in addition to excessive femoral anteversion. Additionally, 4 patients (23.5%) had associated femoral physeal irregularity. Preoperatively, 7 extremities were classified as Langenskiold stage 2, with 12 being classified as stage 2 or less. Overall, the Drennan angle improved from 18.3° to 0.3° by final follow-up at an average of 4.31 years. Children were subdivided into cohorts based upon pre-operative Langenskiold classification: ≤ 2 or ≥3, Figs. 1 and 2 respectively. Children classified as Langenskiold ≤2 (N = 12 extremities) were statistically younger at time of intervention than those classified ≥3 (2.72 ± 0.46 years vs 4.36 ± 2.16 years; P = 0.021). Femoral changes were exclusively present in patients staged ≤2. There were no differences in preoperative Drennan angle (P = 0.32) or mechanical axis (P = 0.65), however, the LDFA was significantly greater in the classification ≤ 2 (12.0 ± 10.4° vs 1.6 ± 1.8°; P = 0.045), Table 2. Of the 17 extremities treated with THE, 15 (88%) demonstrated deformity improvement with 12 (70%) extremities achieving full correction without the need for corrective osteotomy. Two extremities (1 patient Langenskiold stage 4 and 5) demonstrating persistent deformity. Treatment duration was similar between subgroups (1.56 ± 0.6 years vs 1.22 ± 0.1 years; P = 0.36), as was speed of correction (14.17 ± 10.4°/year vs 15.5 ± 8.29°/year; P = 0.84). Postoperative complications are summarized in Table 3. Overall, six patients developed a physeal bar (1 stage 2, 1 stage 3, 3 stage 4, & 1 stage 5) requiring bar excision. Eight extremities demonstrated deformity recurrence/persistence (stage ≤ 2: 33% vs stage ≥3: 100%),
2.1. Statistical analysis Data analysis was performed using SPSS statistical package version 24 (SPSS Inc, Chicago, IL). Significance was set at P < 0.05. Descriptive statistics were generated. Preoperative Langenskiold classification was subdivided into 2 subgroups: ≤ 2or ≥3. Univariate analysis of variance were used to identify risk factors for recurrent deformity, need for further surgery, need for corrective osteotomy, and speed of correction. A multiple regression analysis was used to investigate whether age at treatment, presence of femoral physeal changes, preoperative Langenskiold classification, preoperative 42
Journal of Orthopaedics 20 (2020) 41–45
B.G. Griswold, et al.
Fig. 1. Two year six-month-old female with Langenskiold class I infantile Blount's disease (A), successfully treated with temporary hemiepiphyseodesis (B), with long term follow-up at 13 months (C), 24 months (D), and 8 years 2 months (E).
requiring 24 reoperations including 6 physeal bar excisions and 5 corrective osteotomies (all stage ≥3). Children with Langenskiold stage ≥3 demonstrated a significantly higher rate of complication (average 2.8 vs 0.42; P = 0.015) and a higher rate of reoperation (average 3.6 reoperations vs 0.58, P = 0.0015) per extremity. At final follow-up (≤2: 4.11 ± 2.2 years vs ≥ 3: 4.81 ± 1.8 years; P = 0.07), final Drennan angle and Drennan angle correction were statistically similar.
Table 2 Summary depicting pre-operative and post-operative radiographic criteria and measurements for children with infantile Blount's Disease.
3.1. Multivariant analysis The results of the regression indicated that the model explained 68.5% of the variance and that the model was a significant predictor of Speed of Correction, F (6, 10) = 3.62, p = 0.036. Although Femoral Changes (B = 16.45, P = 0.006) and pre-operative Drennan Angle (B = 1.12, P = 0.01) contributed significantly to the model, all other predictors failed to contribute: age at treatment (B = −3.88, P = 0.091), pre-operative Langenskiold classification (B = 5.86, p = 0.28), BMI percentile for age (B = −0.135, P = 0.31), and Bilaterality (B = −6.57, P = 0.33). The final predictive model was: Speed of Correction = 18.61 + (16.45*Femoral Changes) + (1.12*Preoperative Drennan Angle). Using models for final Drennan angle correction, need for bar resection and need for
Langenskiold Classification ≤2
Langenskiold Classification ≥3
Preoperative Measurement (Degrees)
Mean ± SD
Mean ± SD
p
Drenan Angle Mechanical Axis Lateral Distal Femoral Angle
17.5 ± 4.4 20.2 ± 3.2 12 ± 10.4
20.2 ± 6.2 17.8 ± 11.4 1.6 ± 1.8
0.32 0.65 0.045
2 ± 3.2 1.6 ± 7.8 19.6 ± 34.5
0.48 0.31 0.052
11.8 ± 8.5 11.8 ± 8.5
0.92 0.13
Final Follow-up (Degrees) Drenan Angle −0.3 ± 6.9 Mechanical Axis −3.9 ± 10.5 Lateral Distal Femoral −1.9 ± 4.8 Angle Correction over Treatment Course (Degrees) Drenan Angle 17.8 ± 8.2 Mechanical Axis 24.1 ± 16.5
* Bold font indicates statistical significance p < 0.05.
Fig. 2. Two year five-month-old female with Langenskiold class III infantile Blount's disease (A), treated with temporary hemiepiphyseodesis (B), which originally corrected (C) triggering implant removal at 16 months following surgery (D). The varus deformity recurred with an associated medial tibial physeal bar 16 months following implant removal (E), requiring a medial physeal bar resection and associated tibial corrective osteotomy (F). Early varus deformity was identified 18 months following osteotomy (G) and treated with temporary hemiepiphyseodesis one month later (H). Due to persistent residual deformity 11 months later at age eight (I), a repeat corrective osteotomy was performed 4 months lateral (J), with final radiographic follow-up one year following repeat osteotomy (K), 6 years and 10 months following presentation. 43
Journal of Orthopaedics 20 (2020) 41–45
B.G. Griswold, et al.
with lower recurrence rate. Doyle et al.15 also found that children who achieved deformity correction before age 4 or with Langenskiold classification ≤2 were less likely to experience deformity recurrence through skeletal maturity. Aside from deformity recurrence, concern has been raised in previous studies regarding the potential for hardware failure with tension band plating for THE.16 Previous studies have reported hardware failure rates of 2.3–12.5%.10,11 In the current series, we had a single instance (5.9%) of screw breakage, identified in the Langenskiold stage ≥3 subgroup. Additional complications included surgical site infection/wound dehiscence (N = 5, 29%), physeal bar formation (N = 6, 35%), deformity recurrence/persistence (N = 8, 47%), and overcorrection (N = 1, 5.9%). However, postoperative complications were significantly more common in the Langenskiold stage ≥3 subgroup, as well as have a significantly higher reoperation rate. The results of this study cannot be viewed without acknowledging its limitations. As a retrospective review, there are inherent limitations of the study design. The relative small sample size from a single geographic region limit the extrapolation of these results to other patient population. As a condition affecting children with tremendous remaining growth, our modest follow-up duration only captures a brief snapshot and does not provide a full appreciation of long-term treatment effect of THE on infantile Blount's disease. However, this series represents the longest follow-up duration (4.31 years) reported in the literature. Additionally, there was no control group or historical control group to compare the treatment outcomes.
Table 3 Summary of post-operative complications experienced following treatment with temporary hemiepiphyseodesis, subdivided by Langenskiold classification groups. Complications
Langenskiold Classification ≤2
Langenskiold Classification ≥3
Total
Reoperation Rate Surgical Site Infection Bar Formation Recurrent Deformity Overcorrection Broken Hardware
6 3
18 2
24 5
1 2 0 0
5 6 1 1
6 8 1 1
corrective osteotomy, no variable was identified as independently predictive for the respective outcome of interest.
4. Discussion Treatment of Infantile Blount's disease can be precarious given the extensive growth potential and patient age and size. Although corrective proximal tibial osteotomies have been the historical treatment standard, THE has been investigated as a potential treatment option. This series identified that THE is a viable treatment option for infantile Blount's, with its treatment success varying based upon the severity of deformity with patients presenting with Langenskiold classification ≤2 having the highest rate of treatment success without requiring corrective osteotomy. The use of THE to correct lower extremity angular deformities is not new, having been first introduced by Blount and Clarke in 1949.12 Since that time, the surgical technique has expanded from the less reliable stapling technique, to include the more effective tension band plating constructs.13 Tension band plating constructs for THE are reported to be highly effective for angular lower extremity correction.9,13,14 Kumar et al.9 performed a systematic review on the use of tension band plating for treatment of lower extremity angular deformities, reporting that 91% of the 350 limbs undergoing treated achieved complete angular correction. Specific to infantile Blount's disease, there have been few reports on the use of THE to achieve angular deformity correction. Scott11 was the first to report on the use of THE in the treatment of 12 children with infantile Blount's disease affecting 18 limbs. With an average follow-up of 18.7 months following implant removal, they reported complete angular correction in 89% of limbs, with one patient requiring corrective osteotomy and a second having residual angular deformity. Heflin et al.10 additionally reported on the use of THE for the treatment of 17 children with 27 limbs affected by either infantile and adolescent Blount's disease. Of these 17 children, 6 children with 8 limbs meet the diagnosis for infantile Blount's. Of these, 100% of children were reported to achieve angular correction without the need for a corrective osteotomy at an average of 26.7 month follow-up. One children demonstrated recurrent deformity which was successfully treated with a second treatment using THE. In the current series, we found a 70% total rate of successful angular correction without need for angular correction. Although the cumulative success rate is lower than previous reports, we found that the success rate varied based upon the extent of deformity present at the time of treatment. All children (12/12 limbs) classified as Langenskiold stage ≤2 achieved complete angular correction without requiring corrective osteotomy as compared with only 40% in children with Langenskiold stage ≥3. Additionally, all children Langenskiold stage ≥3 developed a physeal bar requiring bar resection as compared with only 8.3% for Langenskiold stage ≤2. Heflin et al.10 also suggested the role of higher Langenskiold classification on the extent of correction, finding children with Langenskiold stages < 5 corrected more reliably
5. Conclusion Guided growth is a viable treatment option for Infantile Blount's disease presenting with Langenskiold stage ≤2 disease at treatment initiation, with a reported 100% rate of angular correction without the need for corrective osteotomy. The treatment course can expect a 33% rate of recurrent deformity, treated successfully with repeat THE. No children stage ≤2 required corrective osteotomy by final follow-up. Caution should be used with the consideration of guided growth for children presenting with Langenskiold stage ≥3 due to high rate of recurrent deformity and need for subsequent surgeries. Declaration of competing interest None. References 1. Birch JG. Blount disease. J Am Acad Orthop Surg. 2013;21(7):408–418. 2. Richards BS, Katz DE, Sims JB. Effectiveness of brace treatment in early infantile Blount's disease. J Pediatr Orthop. 1998;18(3):374–380. 3. de Miranda Luzo MC, Montenegro NB, Massa BS, de Angeli LR, Cordeiro FG, Guarniero R. Management of infantile blount's disease with molded orthoses: a new perspective. Acta Ortopédica Bras. 2016;24(2):85–89. 4. Shinohara Y, Kamegaya M, Kuniyoshi K, Moriya H. Natural history of infantile tibia vara. J Bone Joint Surg Br. 2002;84(2):263–268. 5. Sabharwal S, Sabharwal S. Treatment of infantile Blount disease: an update. J Pediatr Orthop. 2017;37(Suppl 2):S26–S31. 6. Ferriter P, Shapiro F. Infantile tibia vara: factors affecting outcome following proximal tibial osteotomy. J Pediatr Orthop. 1987;7(1):1–7. 7. McCarthy JJ, Ranade A, Davidson RS. Pediatric deformity correction using a multiaxial correction fixator. Clin Orthop Relat Res. 2008;466(12):3011–3017. 8. Alsancak S, Guner S, Kinik H. Orthotic variations in the management of infantile tibia vara and the results of treatment. Prosthet Orthot Int. 2013;37(5):375–383. 9. Kumar S, Sonanis SV. Growth modulation for coronal deformity correction by using Eight Plates-Systematic review. J Orthop. 2018;15(1):168–172. 10. Heflin JA, Ford S, Stevens P. Guided growth for tibia vara (Blount's disease). Medicine (Baltim). 2016;95(41):e4951. 11. Scott AC. Treatment of infantile Blount disease with lateral tension band plating. J Pediatr Orthop. 2012;32(1):29–34. 12. Blount WP, Clarke GR. Control of bone growth by epiphyseal stapling; a preliminary report. J Bone Joint Surg Am. 1949;31a(3):464–478. 13. Wiemann JMt, Tryon C, Szalay EA. Physeal stapling versus 8-plate hemiepiphysiodesis for guided correction of angular deformity about the knee. J Pediatr Orthop. 2009;29(5):481–485.
44
Journal of Orthopaedics 20 (2020) 41–45
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14. Kadhim M, Gauthier L, Logan K, El-Hawary R, Orlik B. Guided growth for angular correction in children: a comparison of two tension band plate designs. J Pediatr Orthop B. 2018;27(1):1–7. 15. Doyle BS, Volk AG, Smith CF. Infantile Blount disease: long-term follow-up of surgically treated patients at skeletal maturity. J Pediatr Orthop. 1996;16(4):469–476.
16. Burghardt RD, Specht SC, Herzenberg JE. Mechanical failures of eight-plate guided growth system for temporary hemiepiphysiodesis. J Pediatr Orthop. 2010;30(6):594–597.
45
Contents lists available at ScienceDirect
Journal of Orthopaedics journal homepage: www.elsevier.com/locate/jor
Original Article
Guided growth for the Treatment of Infantile Blount's disease: Is it a viable option?☆
T
B. Gage Griswolda,∗, K. Aaron Shawa,b, Harrison Houstonc, Styles Bertranda, David Cearleya a
Department of Orthopaedic Surgery, Children's Hospital of Georgia at Augusta University, Augusta, GA, USA Department of Orthopaedic Surgery, Dwight D. Eisenhower Army Medical Center, Fort Gordon, GA, USA c Medical College of Georgia, Augusta University, Augusta, GA, USA b
A R T I C LE I N FO
A B S T R A C T
Keywords: Infantile Blount's Guided growth Temporary hemiepiphysiodesis Knee Genu varum
Introduction: Guided growth with temporary hemiepiphysiodesis has gained interest as a less invasive means for the treatment of coronal plane lower extremity deformities as well as leg length discrepancies. Its application to infantile Blount's disease has been less reported. The object of this study was to identify predictive factors of guided growth for treatment of infantile Blount's. Methods: A retrospective review was performed of children undergoing guided growth for the treatment of infantile Blount's disease over an eight-year period. Inclusion criteria included treatment with THE for infantile Blount's disease. Clinical information, preoperative Langenskiold classification, and intra-operative and postoperative data. Preoperative variables were used to identify risk factors for speed of correction and the need for subsequent surgery. Results: A total of 11 patients, 17 extremities, meeting inclusionary criteria. Preoperatively, 7 extremities were classified as Langenskiold stage ≥3, with 12 being classified as stage ≤2. Overall, the Drennan's angle improved from 18.3° to 0.3° by final follow-up at an average of 4.31 years. Eight extremities demonstrated deformity recurrence/persistence (stage ≤2:33% vs stage ≥3: 100%), requiring 24 reoperations. Children with Langenskiold stage ≥3 demonstrated a significantly higher rate of reoperation. Conclusion: Guided growth is a viable treatment option for Infantile Blount's disease presenting with Langenskiold stage ≤2 disease at treatment initiation. The treatment course can expect a 33% rate of recurrent deformity, treated successfully with repeat THE. No child stage ≤2 required corrective osteotomy. Caution should be used when considering guided growth for children presenting with Langenskiold stage ≥3.
1. Introduction Infantile Blount's is a result of spontaneous deceleration of the posteromedial growth plate of the proximal tibial physis resulting in a multi-dimensional lower extremity deformity due to sloping of the epiphysis.1 Although the precise etiology of infantile Blount’ disease is unknown, obesity has the strongest correlation with its development. In general, there is a lack of consensus regarding the optimal treatment approach for this condition. Bracing is a controversial treatment method, that has varied results demonstrated in the literature depending upon the severity of disease, age at presentation, and presence of bilateral disease.2–5 A variety of surgical interventions are commonly used for
progressive deformity or disease that fails to respond to bracing. The aim of surgical treatment is to restore a congruent joint surface, a task that can be achieved acutely, or gradually. Classically, the recommended treatment approach has been to perform an acute corrective osteotomy to correct the angular deformity and level the articular surface.6–8 A newer approach with guided growth modulation has gained interest. Guided growth can be performed with either tension band plating or screws, intending to temporarily arresting the normal physis, in the lateral tibial physis in the case of infantile Blount's disease, to allow preferential growth from the diseased physis, and thus angular correction. Although growth modulation with temporary hemiepiphysiodesis (THE) has been shown to be highly effective for the treatment of
☆ The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the Department of Defense or US Government. The authors are employees of the US government. This work was prepared as part of their official duties and, as such there is no copyright to be transferred. ∗ Corresponding author. Department of Orthopaedic Surgery, 1120 15 th Street, BA-3300, Augusta, GA, 30912, USA. E-mail address: [email protected] (B.G. Griswold).
https://doi.org/10.1016/j.jor.2020.01.007 Received 21 November 2019; Accepted 6 January 2020 Available online 10 January 2020 0972-978X/ Published by Elsevier B.V. on behalf of Professor P K Surendran Memorial Education Foundation.
Journal of Orthopaedics 20 (2020) 41–45
B.G. Griswold, et al.
coronal plane deformities with low complications rates,9 little research has focused on its particular application for the treatment of infantile Blount's disease.10,11 The purpose of this study was to investigate the effect of guided growth, using THE, for the treatment of infantile Blount's disease. We hypothesized that younger patients with less severe deformity, defined according to the Langenskiold classification system, would have higher rates of treatment success.
Table 1 Summary of patient demographic information. Variables
2. Materials and methods After obtaining institutional review board approval, records for all pediatric patients who underwent THE with cannulated screws and trans-epiphyseal plate for infantile Blount's disease performed over an eight-year period (2008–2016) were retrospectively reviewed. Inclusion criteria included treatment with temporary hemi-epiphysiodesis, using a tension band plating technique, for isolated Infantile Blount's disease with a minimum of 1-year radiographic follow-up. Identification was performed using a combination of ICD-9 (732.4), ICD-10 (M21.16 and M92.5) codes representing the diagnosis and infantile Blount's disease and common procedural terminology codes 27485, 27477, and 27475, representing possible options for THE. Patients were excluded from study inclusion if they had an underlying diagnosis affecting the musculoskeletal system, performed for a diagnosis other than infantile Blount's disease, underwent treatment other than THE, were treated with technique other than tension band plating, or had < 1-year radiographic follow-up. Clinical information was recorded, including height, weight, body mass index (calculated as a percentile for patient age), race, the age at which the patient underwent surgical correction. Complications were recorded including the development of wound dehiscence, surgical site infections, recurrent deformity, physeal bar formation (diagnosised with the use of Magnetic resonance imaging), hardware complication, and overcorrection. Treatment success was defined as ability to achieve deformity correction with THE without development of physeal bar and/or need for corrective osteotomy. Radiographic information was recorded. Pre-operative Langenskiold classification was determined independently by 2 pediatric orthopaedic surgeons and one pediatric orthopaedic fellow. In the event of discrepancy, imaging studies were collectively reviewed and a consensus classification was determined. Radiographic measurements were recorded at initial treatment and final follow-up, including metadiaphyseal angle (Drennan) angle, lateral distal femoral angle (LDFA), and mechanical axis (MA). Additionally, the presence of femoral physeal abnormalities were recorded. The degree of correction was calculated by subtracting the Drennan angle, LDFA, and MA at final follow-up from the preoperative measurement. Duration of treatment was recorded, defined as the time from initial surgery until hardware removal. The rate of recurrent deformity was recorded, defined as the development of recurrent varus alignment after initial successful correction. Time until recurrence was calculated as the time between hardware removal and the date that recurrent deformity was initially diagnosed. For extremities that did not undergo initial correction, these were defined as persistent deformity and were excluded from this calculation.
Total Limb Cohort
Langenskiold Classification ≤2
Langenskiold Classification ≥3
(n = 17)
(n = 12)
(n = 5)
Mean ± SD
Mean ± SD
Mean ± SD
Age at time of treatment (y) Body Mass Index
3.2 ± 1.4
2.7 ± 0.465
4.36 ± 2.16
93.1 ± 14.5
90.2 ± 16.6
99.99 ± 0
Race
n
n
n
Black White Hispanic Multiple Sex Male Female
9 4 2 2
5 4 1 2
4 0 1 0
6 11
6 6
0 5
Drennan angle, and BMI percentile for age could significantly predict Speed of Correction.
3. Results A total of 57 patients were identified for study inclusions. From these children, 43 were excluded (27 patients with physiologic tibia vara, 8 patients with internal tibial torsion, 4 with tibia vara with associated genetic condition (Achondroplasia (2), Lowe Syndrome, Spondylometaphyseal Dysplasia), 2 were as a result from intrauterine packing, and 1 underwent hemiepiphyseiodesis for a leg length discrepancy. Three additional children were excluded due to a lack of follow-up. This left a total of 11 patients, 17 extremities, meeting inclusionary criteria (average 3.25 years, average BMI for age 93.4, 64.7% female, 63.6% bilateral). Demographic information is summarized in Table 1. Two patients had undergone bracing prior to operative intervention. Associated rotational abnormalities were present in 4 patients with 3 having internal tibial torsion and a fourth have internal tibial torsion in addition to excessive femoral anteversion. Additionally, 4 patients (23.5%) had associated femoral physeal irregularity. Preoperatively, 7 extremities were classified as Langenskiold stage 2, with 12 being classified as stage 2 or less. Overall, the Drennan angle improved from 18.3° to 0.3° by final follow-up at an average of 4.31 years. Children were subdivided into cohorts based upon pre-operative Langenskiold classification: ≤ 2 or ≥3, Figs. 1 and 2 respectively. Children classified as Langenskiold ≤2 (N = 12 extremities) were statistically younger at time of intervention than those classified ≥3 (2.72 ± 0.46 years vs 4.36 ± 2.16 years; P = 0.021). Femoral changes were exclusively present in patients staged ≤2. There were no differences in preoperative Drennan angle (P = 0.32) or mechanical axis (P = 0.65), however, the LDFA was significantly greater in the classification ≤ 2 (12.0 ± 10.4° vs 1.6 ± 1.8°; P = 0.045), Table 2. Of the 17 extremities treated with THE, 15 (88%) demonstrated deformity improvement with 12 (70%) extremities achieving full correction without the need for corrective osteotomy. Two extremities (1 patient Langenskiold stage 4 and 5) demonstrating persistent deformity. Treatment duration was similar between subgroups (1.56 ± 0.6 years vs 1.22 ± 0.1 years; P = 0.36), as was speed of correction (14.17 ± 10.4°/year vs 15.5 ± 8.29°/year; P = 0.84). Postoperative complications are summarized in Table 3. Overall, six patients developed a physeal bar (1 stage 2, 1 stage 3, 3 stage 4, & 1 stage 5) requiring bar excision. Eight extremities demonstrated deformity recurrence/persistence (stage ≤ 2: 33% vs stage ≥3: 100%),
2.1. Statistical analysis Data analysis was performed using SPSS statistical package version 24 (SPSS Inc, Chicago, IL). Significance was set at P < 0.05. Descriptive statistics were generated. Preoperative Langenskiold classification was subdivided into 2 subgroups: ≤ 2or ≥3. Univariate analysis of variance were used to identify risk factors for recurrent deformity, need for further surgery, need for corrective osteotomy, and speed of correction. A multiple regression analysis was used to investigate whether age at treatment, presence of femoral physeal changes, preoperative Langenskiold classification, preoperative 42
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Fig. 1. Two year six-month-old female with Langenskiold class I infantile Blount's disease (A), successfully treated with temporary hemiepiphyseodesis (B), with long term follow-up at 13 months (C), 24 months (D), and 8 years 2 months (E).
requiring 24 reoperations including 6 physeal bar excisions and 5 corrective osteotomies (all stage ≥3). Children with Langenskiold stage ≥3 demonstrated a significantly higher rate of complication (average 2.8 vs 0.42; P = 0.015) and a higher rate of reoperation (average 3.6 reoperations vs 0.58, P = 0.0015) per extremity. At final follow-up (≤2: 4.11 ± 2.2 years vs ≥ 3: 4.81 ± 1.8 years; P = 0.07), final Drennan angle and Drennan angle correction were statistically similar.
Table 2 Summary depicting pre-operative and post-operative radiographic criteria and measurements for children with infantile Blount's Disease.
3.1. Multivariant analysis The results of the regression indicated that the model explained 68.5% of the variance and that the model was a significant predictor of Speed of Correction, F (6, 10) = 3.62, p = 0.036. Although Femoral Changes (B = 16.45, P = 0.006) and pre-operative Drennan Angle (B = 1.12, P = 0.01) contributed significantly to the model, all other predictors failed to contribute: age at treatment (B = −3.88, P = 0.091), pre-operative Langenskiold classification (B = 5.86, p = 0.28), BMI percentile for age (B = −0.135, P = 0.31), and Bilaterality (B = −6.57, P = 0.33). The final predictive model was: Speed of Correction = 18.61 + (16.45*Femoral Changes) + (1.12*Preoperative Drennan Angle). Using models for final Drennan angle correction, need for bar resection and need for
Langenskiold Classification ≤2
Langenskiold Classification ≥3
Preoperative Measurement (Degrees)
Mean ± SD
Mean ± SD
p
Drenan Angle Mechanical Axis Lateral Distal Femoral Angle
17.5 ± 4.4 20.2 ± 3.2 12 ± 10.4
20.2 ± 6.2 17.8 ± 11.4 1.6 ± 1.8
0.32 0.65 0.045
2 ± 3.2 1.6 ± 7.8 19.6 ± 34.5
0.48 0.31 0.052
11.8 ± 8.5 11.8 ± 8.5
0.92 0.13
Final Follow-up (Degrees) Drenan Angle −0.3 ± 6.9 Mechanical Axis −3.9 ± 10.5 Lateral Distal Femoral −1.9 ± 4.8 Angle Correction over Treatment Course (Degrees) Drenan Angle 17.8 ± 8.2 Mechanical Axis 24.1 ± 16.5
* Bold font indicates statistical significance p < 0.05.
Fig. 2. Two year five-month-old female with Langenskiold class III infantile Blount's disease (A), treated with temporary hemiepiphyseodesis (B), which originally corrected (C) triggering implant removal at 16 months following surgery (D). The varus deformity recurred with an associated medial tibial physeal bar 16 months following implant removal (E), requiring a medial physeal bar resection and associated tibial corrective osteotomy (F). Early varus deformity was identified 18 months following osteotomy (G) and treated with temporary hemiepiphyseodesis one month later (H). Due to persistent residual deformity 11 months later at age eight (I), a repeat corrective osteotomy was performed 4 months lateral (J), with final radiographic follow-up one year following repeat osteotomy (K), 6 years and 10 months following presentation. 43
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with lower recurrence rate. Doyle et al.15 also found that children who achieved deformity correction before age 4 or with Langenskiold classification ≤2 were less likely to experience deformity recurrence through skeletal maturity. Aside from deformity recurrence, concern has been raised in previous studies regarding the potential for hardware failure with tension band plating for THE.16 Previous studies have reported hardware failure rates of 2.3–12.5%.10,11 In the current series, we had a single instance (5.9%) of screw breakage, identified in the Langenskiold stage ≥3 subgroup. Additional complications included surgical site infection/wound dehiscence (N = 5, 29%), physeal bar formation (N = 6, 35%), deformity recurrence/persistence (N = 8, 47%), and overcorrection (N = 1, 5.9%). However, postoperative complications were significantly more common in the Langenskiold stage ≥3 subgroup, as well as have a significantly higher reoperation rate. The results of this study cannot be viewed without acknowledging its limitations. As a retrospective review, there are inherent limitations of the study design. The relative small sample size from a single geographic region limit the extrapolation of these results to other patient population. As a condition affecting children with tremendous remaining growth, our modest follow-up duration only captures a brief snapshot and does not provide a full appreciation of long-term treatment effect of THE on infantile Blount's disease. However, this series represents the longest follow-up duration (4.31 years) reported in the literature. Additionally, there was no control group or historical control group to compare the treatment outcomes.
Table 3 Summary of post-operative complications experienced following treatment with temporary hemiepiphyseodesis, subdivided by Langenskiold classification groups. Complications
Langenskiold Classification ≤2
Langenskiold Classification ≥3
Total
Reoperation Rate Surgical Site Infection Bar Formation Recurrent Deformity Overcorrection Broken Hardware
6 3
18 2
24 5
1 2 0 0
5 6 1 1
6 8 1 1
corrective osteotomy, no variable was identified as independently predictive for the respective outcome of interest.
4. Discussion Treatment of Infantile Blount's disease can be precarious given the extensive growth potential and patient age and size. Although corrective proximal tibial osteotomies have been the historical treatment standard, THE has been investigated as a potential treatment option. This series identified that THE is a viable treatment option for infantile Blount's, with its treatment success varying based upon the severity of deformity with patients presenting with Langenskiold classification ≤2 having the highest rate of treatment success without requiring corrective osteotomy. The use of THE to correct lower extremity angular deformities is not new, having been first introduced by Blount and Clarke in 1949.12 Since that time, the surgical technique has expanded from the less reliable stapling technique, to include the more effective tension band plating constructs.13 Tension band plating constructs for THE are reported to be highly effective for angular lower extremity correction.9,13,14 Kumar et al.9 performed a systematic review on the use of tension band plating for treatment of lower extremity angular deformities, reporting that 91% of the 350 limbs undergoing treated achieved complete angular correction. Specific to infantile Blount's disease, there have been few reports on the use of THE to achieve angular deformity correction. Scott11 was the first to report on the use of THE in the treatment of 12 children with infantile Blount's disease affecting 18 limbs. With an average follow-up of 18.7 months following implant removal, they reported complete angular correction in 89% of limbs, with one patient requiring corrective osteotomy and a second having residual angular deformity. Heflin et al.10 additionally reported on the use of THE for the treatment of 17 children with 27 limbs affected by either infantile and adolescent Blount's disease. Of these 17 children, 6 children with 8 limbs meet the diagnosis for infantile Blount's. Of these, 100% of children were reported to achieve angular correction without the need for a corrective osteotomy at an average of 26.7 month follow-up. One children demonstrated recurrent deformity which was successfully treated with a second treatment using THE. In the current series, we found a 70% total rate of successful angular correction without need for angular correction. Although the cumulative success rate is lower than previous reports, we found that the success rate varied based upon the extent of deformity present at the time of treatment. All children (12/12 limbs) classified as Langenskiold stage ≤2 achieved complete angular correction without requiring corrective osteotomy as compared with only 40% in children with Langenskiold stage ≥3. Additionally, all children Langenskiold stage ≥3 developed a physeal bar requiring bar resection as compared with only 8.3% for Langenskiold stage ≤2. Heflin et al.10 also suggested the role of higher Langenskiold classification on the extent of correction, finding children with Langenskiold stages < 5 corrected more reliably
5. Conclusion Guided growth is a viable treatment option for Infantile Blount's disease presenting with Langenskiold stage ≤2 disease at treatment initiation, with a reported 100% rate of angular correction without the need for corrective osteotomy. The treatment course can expect a 33% rate of recurrent deformity, treated successfully with repeat THE. No children stage ≤2 required corrective osteotomy by final follow-up. Caution should be used with the consideration of guided growth for children presenting with Langenskiold stage ≥3 due to high rate of recurrent deformity and need for subsequent surgeries. Declaration of competing interest None. References 1. Birch JG. Blount disease. J Am Acad Orthop Surg. 2013;21(7):408–418. 2. Richards BS, Katz DE, Sims JB. Effectiveness of brace treatment in early infantile Blount's disease. J Pediatr Orthop. 1998;18(3):374–380. 3. de Miranda Luzo MC, Montenegro NB, Massa BS, de Angeli LR, Cordeiro FG, Guarniero R. Management of infantile blount's disease with molded orthoses: a new perspective. Acta Ortopédica Bras. 2016;24(2):85–89. 4. Shinohara Y, Kamegaya M, Kuniyoshi K, Moriya H. Natural history of infantile tibia vara. J Bone Joint Surg Br. 2002;84(2):263–268. 5. Sabharwal S, Sabharwal S. Treatment of infantile Blount disease: an update. J Pediatr Orthop. 2017;37(Suppl 2):S26–S31. 6. Ferriter P, Shapiro F. Infantile tibia vara: factors affecting outcome following proximal tibial osteotomy. J Pediatr Orthop. 1987;7(1):1–7. 7. McCarthy JJ, Ranade A, Davidson RS. Pediatric deformity correction using a multiaxial correction fixator. Clin Orthop Relat Res. 2008;466(12):3011–3017. 8. Alsancak S, Guner S, Kinik H. Orthotic variations in the management of infantile tibia vara and the results of treatment. Prosthet Orthot Int. 2013;37(5):375–383. 9. Kumar S, Sonanis SV. Growth modulation for coronal deformity correction by using Eight Plates-Systematic review. J Orthop. 2018;15(1):168–172. 10. Heflin JA, Ford S, Stevens P. Guided growth for tibia vara (Blount's disease). Medicine (Baltim). 2016;95(41):e4951. 11. Scott AC. Treatment of infantile Blount disease with lateral tension band plating. J Pediatr Orthop. 2012;32(1):29–34. 12. Blount WP, Clarke GR. Control of bone growth by epiphyseal stapling; a preliminary report. J Bone Joint Surg Am. 1949;31a(3):464–478. 13. Wiemann JMt, Tryon C, Szalay EA. Physeal stapling versus 8-plate hemiepiphysiodesis for guided correction of angular deformity about the knee. J Pediatr Orthop. 2009;29(5):481–485.
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14. Kadhim M, Gauthier L, Logan K, El-Hawary R, Orlik B. Guided growth for angular correction in children: a comparison of two tension band plate designs. J Pediatr Orthop B. 2018;27(1):1–7. 15. Doyle BS, Volk AG, Smith CF. Infantile Blount disease: long-term follow-up of surgically treated patients at skeletal maturity. J Pediatr Orthop. 1996;16(4):469–476.
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