Outcome of Different Surgical Techniques for Management of Adolescent Tibia Vara; Systematic review

Article information Background: Adolescent tibia vara [ATV] is a multiplanar malformation that can cause diminished function and permanent damage. ATV is believed to be a multifaceted developmental disease of the proximal tibia, which results in a malformation of the varus and procurvatum. In genetically vulnerable individuals, this disorder may also be partially attributed to mechanical strain. The Aim of the work: This pooled analysis goal is to evaluate and compile the data about the efficacy and complications of the most popular surgical lines of treatment of tibia vara in adolescents: osteotomy, Ilizarov, and hemiepiphysiodesis. Methods: Considering the search strategy, a literature study was conducted from 2010 to 2020 in the Web of Science, PubMed, Scopus, and Cochrane datasets. Studies were selected if it included. This systematic review had 15 published papers with a total sample size of 357 limbs. Results: Temporal hemiepiphysiodesis is used effectively to treat mild/moderate ATV in patients with sufficient growth. Temporal hemiepiphysiodesis has been linked to an elevated failure and recurrence rate of approximately 28.4%. In managing ATV, a modified Rab osteotomy with minimal fixation using two or three screws yields encouraging outcomes. However, the post-operative time of healing is affected by BMI. Thus, it's not the best choice for obese patients with ATV. For correcting mild to moderate ATV, medial opening wedge high tibial osteotomy—with or without a bone graft—is an appropriate approach. Conclusion: The best surgical technique for adolescent tibia vara depends on the patient's circumstances. Osteotomy is generally preferred over hemiepiphysiodesis due to its lower recurrence rate. The use of simple circular frame fixation with proximal tibial osteotomy is the ideal option for treating neglected ATV, mainly when the patient is obese and has severe deformities.


INTRODUCTION
Tibia vara [TV], also known as Blount's disease, is a pathologic complicated angular malformation of the lower extremities centred at the upper tibial physis that results in a bow leg malformation [1,2] .The hallmark of TV is a localized lack of growth in the posteromedial region of the upper tibial metaphysis and epiphysis.TV is a growth disease characterized by a progressive angular deformity of the tibia brought via a disturbance in the growth of the epiphyseal cartilage and metaphysis.This results in a varus [bowleg] deformity, with medial twisting of the tibia and flexion of the diaphysis [shaft] on the proximal tibial epiphysis [3] .
TV pathogenesis is believed to result from imbalanced biomechanical load distribution and hereditary predisposition.Pathologic varus malformation is caused by asymmetrical growth resulting from biomechanical loading of the proximal tibial physis [1,2] .People with greater thigh circumference and BMI may have varus moments, which are caused by their gait pattern and can worsen the deformity.Frequently, there may be concomitant abnormalities of the distal tibia and femur [varus or valgus] [4] .
Nine decades after the initial description, TV treatment is still complex.It is necessary to consider the femur's role in the varus malalignment [5] .Restoring limb alignment, joint congruency, equalizing limb length, and meticulous follow-up are all part of the management, as recurrences can happen in as many as 50% of cases [6,7] .
The simplicity of applying the technique, the period it takes to complete curvature repair in clinical and radiographic pictures, the avoidance of recurrence, and the comorbidities [i.e., nerve injury, infection, non-union, malunion] vary among all these procedures [7,21] .
As far as we know, no prior systematic review has evaluated the effectiveness of different techniques in treating adolescent tibia vara [ATV] with a focus on the success rate and the optimal technique for each case.This pooled analysis goal is to evaluate and compile the data about the efficacy and complications of the most popular surgical lines of treatment of tibia vara in adolescents; osteotomy, Ilizarov and hemiepiphysiodesis and the rate of recurrence of each of them.

METHODS
The PRISMA [Preferred Reporting Items for Systematic Reviews and Meta-analyses] guidelines were followed in conducting this systematic study [22] .Search framework using PICOS [participants, intervention, outcome, and study design] model: Participants: studies including patients with adolescent tibia vara, intervention [exposure]: studies including any surgical intervention [osteotomy, hemiepiphysiodesis, Ilizarov], outcome: radiological outcomes, recurrence and complications, study design: Any study design except case report or animal studies.

Eligibility criteria:
We included studies that included patients who suffered from adolescent tibia vara [above ten years] and published after 2000.We excluded studies including children below ten years old, studies published before 2000, non-English studies, case reports, animal studies, non-full text studies [abstract only], or letters to the editor.Studies selection: Summaries and paper titles were used to filter the search findings.Applying Endnote software, the redundant studies were eliminated.After identifying relevant research, the papers were obtained and examined to ascertain their appropriateness for eventual inclusion.A manual search was conducted for more articles in the citation lists of all the relevant papers.
Data extraction: Applying a standard Microsoft Excel software data extraction form, the researcher obtained the following information from the included articles: study characteristics as the author, year, study design, patient number, follow-up period, patient characteristics as [age, sex, and BMI], intervention characteristics, functional outcome, and radiological outcomes, complications, and recurrence.

Quality assessment:
The level of quality was evaluated using the Joanna Briggs Institute [JBI] Critical Appraisal Tool.The 10-item JBI checklist for the series of cases assesses the following: if subjects were included consecutively; the reliability of the detection approaches; the recording of demographic details, clinical data, and outcomes; the presentation of clinic demographic data; the relevance of the method of statistical analysis; and finally, if the eligibility criteria were met [23] .
Synthesis methods: Using the employed methodology, the retrieved data were narratively synthesized in groups.We performed a narrative synthesis in accordance with the Synthesis without Meta-Analysis [SWiM] guidelines [24] and presented the impact variables found in the selected publications.

Success rate:
The acceptable degree of improved function in ATV can vary based on how severe the deformity is and the treatment goals.In general, the intervention aims to return normal alignment and function of the affected leg to the greatest extent possible [25] .
Clinical outcome scores before and after surgery were retrieved.The most recent documented follow-up clinical values were applied.When a favourable or excellent outcome was observed during follow-up and paired with a recognized grading system, the therapeutic plan was considered successful.To be clear, if an ankle showed a post-operative functioning score of 80 or higher at the last follow-up, the treatment was deemed effective.The success rate was defined as the proportion of favourable and excellent functioning results [26] .

RESULTS
Searching on scientific databases [PubMed, Scopus, Web of Science, and Cochrane Library] using an advanced search strategy resulted in 390 papers, and 20 were collected from other sources.One hundred eighty-nine duplicated papers were excluded using endnote software.Then, the researcher performed title and abstract screening on the remaining 221 papers.During this process, 168 studies were excluded due to different causes, 10 non-English studies, 145 papers included not-adolescent tibia vara, and 13 studies abstract only available.After title and abstract screening, full-text screening was performed on 53 articles.Throughout full-text screening, 38 studies were excluded [6 case reports, 4 review articles, 13 other techniques, 10 infantile tibia vara, and 5 studies published before 2000].The remaining 15 articles were involved in our pooled analysis [Figure 1].The summary of the included studies is illustrated in Table 2.The study design was a case series in all included studies.The total sample size was 357 limbs.From them 7 patients [10 limbs] underwent external fixation using Ilizarov in one study [27] , 95 patients [102 limbs] in 5 studies [28][29][30][31][32] underwent hemiepiphysiodesis, 50 patients [58 limbs] in 3 studies underwent tibial osteotomy, and 112 patients [129 limbs] in 6 studies underwent tibial osteotomy combined with external fixation.The age of patients included was more than 11 years ranging from [11 to 21 years old].The majority of included patients were obese.The time of external fixation in 4 studies ranged from 11 to 16 weeks, and the follow-up period ranged from 5 to 48 months.

Quality assessment:
The quality assessment was performed using the JBI checklist.Among the included studies, three scored ten out of ten [8, 33, 34]   , and one study scored six out of ten [35] with an overall mean score of 8.3.
In all included studies, there were clear inclusion criteria, relevant techniques for each participant in the case series, and condition identification for each participant using valid methods.The last reported criteria were appropriate statistical analysis [9/15].The outcome was reported in 11 included studies.Reporting of clinical information of the participants was evident in all included studies.In a recent retrospective study performed by Zein et al. [36] to assess the using of proximal tibial osteotomy with Ilizarov external fixator for adolescent tibia vara.The knee score improved from 51±11.2 preoperative to 94± 6.8 post-operative.The functional outcome was further illustrated in Table [4].The complication rate was 90% after external fixation using Ilizarov followed by 52% after external fixation combined with osteotomy.superficial wound infection after external fixation was 80% and decreased to 64% when combined with tibial osteotomy.The highest recurrence rate was after hemiepiphysiodesis.28.4% of included patients underwent further correction attempt using tibial osteotomy technique [Table 5].The recurrence rate was higher after hemiepiphysiodesis [41.4%] than after osteotomy technique [3.4%] or osteotomy combined with external fixation [2.4%] [p=0.00].
Patients' satisfaction: Patients' satisfaction was reported in only three studies.In the Hegazy et al. [37] 's study, at the end follow-up, every patient expressed satisfaction with their operation.In Aly et al. [38] , six months after the cast was taken off and full weight bearing was achieved postoperatively, there was a notable improvement in the Lysholm score, with 15 patients scoring excellent [78.9%],Two good [10.5%],one fair [5.2%], and one poor [5.2%].es Yes Yes N/R Yes Yes Yes No Yes No 7 Radwan [39] Yes Yes Yes Yes Yes Yes Yes No No No 7 Danino et al. [30] Yes Yes Yes Yes Yes Yes Yes No N/R Yes 8 Heflin et al. [29] Yes Yes Yes Yes Yes Yes Yes Yes No No 8 Mcintosh et al. [28] Yes Yes Yes Yes Yes Yes Yes Yes Yes No 9 Murphy et al. [32] Yes Yes Yes N/R No Yes Yes Yes Yes Yes 8 Oto et al. [31] Yes Yes Yes No No Yes Yes Yes Yes NO 7 Aly et al. [38] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes 9 Eidelman et al. [35] Yes Yes Yes N/R N/R Yes Yes No NO Yes 6 Gordon et al. [8] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes 10 Griswold et al. [34] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes 10 khaled et al. [40] Yes Yes Yes Yes Yes Yes Yes Yes Yes NO 9 Hegazy et al. [37] Yes Yes Yes No No Yes Yes Yes Yes Yes 8 Sachs et al. [33] Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes 10 Zein et al. [36] Yes Yes Yes Yes Yes Yes Yes Yes N/R Yes 9

DISCUSSION
ATV is a multiplanar malformation that can cause diminished function and permanent damage.ATV is believed to be a multifaceted developmental disease of the proximal tibia, which results in a malformation of the varus and procurvatum.In genetically vulnerable individuals, this disorder may also be partially attributed to mechanical strain [25] .The Heuter-Volkmann principle is considered to cause physeal damage when severe biomechanical stresses are applied to the medial proximal tibia.This leads to asymmetric medial physeal growth restriction and pathological varus deformities [41,42] .
Restoring the joint's mechanical axis and alignment, enhancing function, and lowering the likelihood of early joint deterioration should be the objectives of treatment [43] .
Because of the patient's posture and closeness to skeletal maturation, conservative treatment-bracing, for example-is unsuccessful for the late-onset variety and shouldn't be taken into consideration.To identify and treat every contributing factor to the malformation, comprehensive surgical preparation is necessary before attempting a surgical solution.Creating the perfect reconstructive design requires careful pre-operative preparation and deformity assessment, considering all concomitant abnormalities and skeletal development [25] .
The two mainstays of surgical options are either osteotomy or growth regulation, both of which can be performed using procedures for either progressive or acute repair [40] .
As far as we know, this is the first pooled analysis focusing on the efficacy of various surgical techniques in treating adolescent tibia vara.This systematic review included 15 published papers with a total sample size of 357 limbs.From the 7 patients [10 limbs] underwent external fixation using Ilizarov in one study, 95 patients [102 limbs] underwent hemiepiphysiodesis in 5 studies, 50 patients [58 limbs] in 3 studies underwent tibial osteotomy, and 112 patients [129 limbs] in 6 studies underwent tibial osteotomy combined with external fixation.The majority of included patients were obese.Although not always, patients with ATV are usually obese; in the adolescent cohort, 90% of cases were observed to be obese.The degree of the deformities and the patient's residual growth are taken into account when treating ATV [41,44] .
Our study investigated that temporal hemiepiphysiodesis has a success rate of 87.5% in treating mild to moderate adolescent tibia vara with sufficient growth.However, the use of temporal hemiepiphysiodesis isn't the best choice for the treatment of obese patients with severe ATV.
ATV can be effectively treated by lateral proximal tibial hemiepiphysiodesis, also known as directed growth, especially in individuals with a physis that functions, enough growth potential, and mild to moderate deformities [32,34,45] .This procedure is appealing since it focuses straight on the point of deformity, has a quick recovery period, and requires minimal invasiveness; nonetheless, outcomes for this patient group can vary; thus, caution is advised.Up to 50% of instances have been documented to have inadequate correction, having older patients [age 14] and those with higher BMIs [45] and more deformities having a higher failure rate [46] .Obesity patients also have concerns about implant breakage.Recent results, however, indicate that hemiepiphysiodesis alone may be able to fully treat 88% or more of individuals with ATV [47,48] .
Many methods have been employed with good results, such as hemiepiphysiodesis with a tension band plate and screw construct, as first proposed by Stevens [19] , or percutaneous transphyseal screws, which were recently shown to produce an efficient and secure correction with little chance of failure of the implant even in obese individuals [32] .
Our result confirmed the highest failure and recurrence rate after hemiepiphysiodesis; 28.4% underwent further correction attempts using the tibial osteotomy technique.Scott [49] reported untoward events after hemiepiphysiodesis, including backing out of implants, repeated deformity after hardware elimination, and even inhibition of growth after physeal staples introduction.
Schroerlucke et al. [50] discovered that 44% of their ATV patients' deformities could not be corrected by the extraperiosteal plates.Oto et al. [31] stated that none of their ATV patients were able to make the necessary corrections using the plate.
In a previous systematic review, after temporary hemipiphysiodesis, patients with ATV had a 49% reoperation rate.They expected an overestimated number and justified it with selection and historical bias [46] .Children who have had aberrant physis abnormalities, including ATV or Rickets, have frequently needed unscheduled procedures in the future, and their outcomes have been less predictable [51] .This may be explained by the fact that, according to hand imaging, Blount patients typically have more developed skeletal ages than chronological ages, making it more challenging to determine how much growth will remain.Being older at hemiepiphysiodesis increases the chance that skeletal maturity won't produce a sufficient correction.This could have to do with the restricted growth that teenagers still have and the advanced bone age that these fat children have been documented to have [52] .
For many years, tibial osteotomy has been a popular surgical procedure for treating ATV, particularly in cases when kids are getting close to adulthood.Osteotomy, in contrast to directed growth, is independent of age or residual growth and permits complete repair of all deformity elements [varus, procurvatum, internal torsion, leg length disparity].According to the surgeon's preference, several fixation techniques can be used with either an acute or gradual repair [34,45] .
Our systematic review demonstrated that in the treatment of ATV, a modified Rab osteotomy with minimum fixation by two or three screws exhibits encouraging outcomes with the satisfactory repair of varus deformity [coronal plane], internal torsion [axial plane], and procurvatum [sagittal plane].However, the post-operative time of healing is affected by BMI.Thus, it's not the best choice for obese patients with ATV.One effective method for treating mild to moderate ATV is medial opening wedge high tibial osteotomy, either with or without a bone graft.
An osteotomy of the proximal tibia using an opening or closing wedge can be used to treat acute ATV.For patients who wish to avoid external fixation and have mild to moderate deformities, this is a desirable choice.Both plates and intramedullary nails can be used for internal fixing procedures.Immediate weight bearing, avoiding intricate corrective programs, and a decreased chance of infection and pin site issues are some potential advantages.However, this has to be evaluated against the higher risk of delayed union, compartment syndrome, and neurovascular problems [25] .Furthermore, while some authors have claimed that acute correction is generally less reliable than other methods, others have found little evidence to support a preference for one method over another.For these reasons, gradually, treatment methods for complex tibial defects have become widely accepted [53] .
Our study revealed that gradual correction using a hinged two-ring Ilizarov frame requires a longer time for repair of deformity when used alone and has been linked to an elevated rate of superficial pin tract infections and a difference in residual limb length.However, the use of simple circular frame fixation with proximal tibial osteotomy decreased the correction time and the early knee degenerative arthritis risk.Moreover, when treating cases of neglected ATV, it is a great option, particularly when treating patients who are obese and have severe deformities.
For TV, gradual repair via external fixation and proximal tibial osteotomy is commonly used.Gradual repair makes use of Ilizarov's initial description of distraction osteogenesis.In actuality, a hexapod external fixator is usually utilized for this.However, other methods, such as monolateral approaches, are rarely employed .This technique's main advantage is its capacity to treat every aspect of deformity at the same time, gradually, and with the least amount of invasiveness.Among other things, the patient may benefit from increased corrective precision, a quicker healing period, increased safety for the local neurovascular structures, and the capacity to permit early weight-bearing and range of motion [54,55] .
Gordon et al. [8] reported that if the femur varus is greater than five degrees, it is advised to repair the tibial and femoral abnormalities at the same time.The authors present a series of surgical procedures that include proximal tibial valgus osteotomy using an Ilizarov external fixator in combination with either plate-assisted distal femur valgus osteotomy or, in cases where growth is still present, hemiepiphysiodesis of the lateral distal femur.This all-encompassing strategy, which addressed each contributing deformity independently, prevented shearing forces that could have been seen with severe joint line obliquity and restored both joint mechanical and horizontal lines.The present framework for treating ATV is based on the integrated approach's guiding principles [56] .

Conclusion:
For treating ATV, temporal hemiepiphysiodesis is not the best option and is linked to an elevated recurrence rate because it is challenging to anticipate remaining growth effectively.A modified Rab osteotomy with minimal fixation using two or three screws yields encouraging outcomes for the treatment of non-obese patients with ATV.For correcting mild to moderate ATV, medial opening wedge high tibial osteotomy-with or without a bone graft-is an appropriate approach.For correcting mild to moderate ATV, medial opening wedge high tibial osteotomy-with or without a bone graft-is an appropriate approach.Using the Ilizarov frame alone requires a longer time for correction and is associated with a higher rate of superficial pin tract infections and a difference in residual limb length.The use of simple circular frame fixation with proximal tibial osteotomy is the ideal option for treating neglected ATV, mainly when the patient is obese and has severe deformities.The recurrence rate was higher after hemiepiphysiodesis [41.4%]  than after osteotomy technique [3.4%] or osteotomy combined with external fixation [2.4%] [p=0.00].

Table [ 2
]: Summary of included studies

Table [ 5
]: Evaluation for recurrence rate after surgical treatment