Opening-Wedge High Tibial Osteotomy with a Cancellous Strut Bone Allograft Is Inadequate for Achieving Satisfactory and Lasting Correction in Neglected Infantile Tibia Vara: Results from a Cohort of 29 Patients.

Background: Infantile tibia vara (ITV) is a rare proximal tibia deformity in infancy, leading to progressive knee varus. High tibial osteotomy is commonly practiced but has high recurrence rates. This study analyzed factors affecting treatment failure and recurrence in children undergoing opening-wedge high tibial osteotomy (OWHTO) for ITV. Methods: We retrospectively studied children with ITV who had OWHTO with a press-fit cancellous bone allograft between 2000 and 2020, with ≥2-year follow-up. Outcomes included recurrence (knee varus with tibiofemoral angle > 10°), complications, and reintervention. Results: We analyzed 39 knees in 29 patients (mean age: 4.8 ± 1.9 years; median follow-up: 7.4 years). Recurrence occurred in 22 cases (56%). Age at surgery significantly influenced recurrence, with rates of 16% before age 5 versus 95% later (hazard ratio: 12.0, p = 0.001). Langenskiöld stage also affected recurrence (ß-coefficient: 2.7, 95% C.I. 1.0-4.5, p = 0.002; pseudo-R-squared: 0.50, p = 0.001), with recurrence in all stage IV or higher cases. Conclusions: Early diagnosis and treatment before age 5, ideally with Langenskiöld stage III or lower, are crucial for stable correction with OWHTO alone. Late, high-grade ITV may require combined, acute or gradual, and/or staged correction. Further evidence is needed for optimal management.

Tension-Band Plating for Infantile Blount Disease: Efficacy and Outcomes Comprehensive Review.

Infantile Blount disease (IBD) is a pathologic varus knee deformity that, if left untreated, can lead to abnormal gait, limb length discrepancy, and pain. Traditionally, bracing and tibial osteotomy have been the primary treatments. More recently, guided growth with tension-band plating (TBP) has gained popularity, although there is a lack of data stratifying between the infantile, juvenile, and adolescent disease types. Therefore, the present review aims to determine the efficacy and complications of TBP in the IBD population. A systematic review was conducted following the PRISMA guidelines. Eligible studies included those focused on guided growth correction for IBD. Studies that did not stratify subjects by subgroup (infantile, juvenile, and adolescent) within their analysis were excluded. The outcomes of interest included demographic information, correction rate, failure rate, recurrence rate, and postoperative complications. Database review identified 541 studies. After screening, seven studies met our inclusion criteria, all of which were retrospective observational studies published between 2012 and 2022. In total, 92 limbs afflicted with Infantile Blount Disease underwent treatment with TBP. The recorded follow-up period ranged from four months to eight years. The age of patients at the time of surgery varied from 1.8 to nine years. On average, there was a 78.99% correction of deformities, with a range of 57.14% to 100%. Six studies provided data on failure and recurrence rates, with an average rate of 23.47%. Notably, infection and hardware failure emerged as the most prevalent postoperative complications, with mean rates of 11.44% and 9.50%, respectively. The average reoperation rate was 29.90%, with a range from 0.00% to 47.06%. The current literature shows a high rate of deformity correction with a relatively low risk of complications after TBP for IBD. Given the reported reoperation rates greatly varied, further data is needed to determine risk factors for reoperation following TBP. Our results suggest that guided growth with TBP may be a preferable first-line treatment for IBD.

Tibia vara caused by focal fibrocartilaginous dysplasia: A rare case report.

Focal fibrocartilaginous dysplasia is an uncommon benign bone condition that predominantly affects children and typically leads to varus deformities in the proximal tibia. It was first described by Bell in 1985. The etiology remains unknown and the diagnosis is radiological; biopsy is not necessary. We present a case of a 2-year-old child who presented to our department for a right limb varus deformity caused by focal fibrocartilaginous dysplasia.

Fixed-Bearing Unicompartmental Knee Arthroplasty in Tibia Vara Knees Results in Joint Surface Malalignment and Varus Joint Line Obliquity, but Does Not Affect Functional Outcomes at Greater Than 5 Years Follow-Up.

BACKGROUND: This study aimed to investigate the clinical outcomes of fixed-bearing medial unicompartmental knee arthroplasty (UKA) for tibia vara knees and the associated changes in joint space malalignment (JSM) and joint line obliquity (JLO). METHODS: We retrospectively analyzed a consecutive group of 100 patients who underwent fixed-bearing medial UKA with a preoperative medial proximal tibia angle (MPTA) ≥86° (n = 50) and MPTA <86° (n = 50) and who had a minimum 5-year follow-up. Radiological parameters, including the hip-knee-ankle angle, MPTA, and the postoperative JSM and JLO, were measured. Functional evaluation was performed using the range of motion, visual analog scale, Knee Society Knee Score, Knee Society Function Score, and Western Ontario and McMaster Universities Osteoarthritis Index score. RESULTS: The MPTA <86° group showed significantly higher postoperative JLO (91.8 versus 90.4°, respectively; P = .002) and JSM (6.1 versus 4.2°, respectively; P = .026) compared to the MPTA ≥86° group. Functional outcomes, including range of motion, visual analog scale, Knee Society Knee Score, Knee Society Function Score, and Western Ontario and McMaster Universities Osteoarthritis Index scores, were not significantly different between the 2 groups. CONCLUSIONS: Fixed-bearing medial UKA is a safe and effective surgical option for patients who have tibia vara knees, as an increase in JLO and JSM postoperatively does not have a clinically relevant impact, even after a minimum 5-year follow-up.

Recurrence and Complication Rates of Surgical Treatment for Blount's Disease in Children: A Systematic Review and Meta-Analysis.

BACKGROUND: Blount's disease is a growth disorder of the proximal tibia that causes progressive genu varum in children. Surgical treatment is recommended if the deformity worsens, but which intervention is best remains controversial. This study aims to identify factors influencing outcomes and determine the most effective surgical approach. METHODS: A systematic review was conducted of studies published before January 2022. RESULTS: In total, 63 retrospective studies with CEBM IIIb/IV levels were included (1672 knees in 1234 patients). The most commonly reported treatment was acute correction via osteotomy (47%), followed by hemiepiphysiodesis (22%) and gradual correction (18%). Combined procedures were reported in 13% of cases. The overall recurrence rate was 18%, with a significant difference when comparing the recurrence rates after gradual correction with those after hemiepiphysiodesis (7% and 29%, respectively). Major complications beyond recurrence were observed in 5% of cases. A meta-analysis of the available raw data showed a significantly increased recurrence rate (39%) among treated children who were between 4.5 and 11.25 years of age and were followed for a minimum follow-up of 2.5 years. CONCLUSIONS: Overall, poor evidence with which to establish an optimal treatment for Blount's disease was found. This study remarked on the need for early diagnosis, classification, and treatment of infantile tibia vara, since a significant rate of recurrence was found in neglected cases.

Impact of Proximal Tibial Varus Anatomy on Survivorship After Medial Unicondylar Knee Arthroplasty.

BACKGROUND: Precise indications for medial unicondylar knee arthroplasty (UKA) continue to be defined. It is unclear if patients who have proximal tibia vara should be considered candidates for UKA. The purpose of this study was to evaluate the impact of proximal tibial varus alignment on outcomes after UKA. METHODS: A retrospective review identified 2,416 patients (3,029 knees) who underwent mobile-bearing medial UKA with 2-year minimum follow-up or revision. Preoperative radiographs were evaluated, and medial proximal tibial angle (mPTA) was measured. Patients were grouped into two groups as follows: mPTA <80 degrees and mPTA ≥80 degrees. Analyses were performed on the impact of mPTA on clinical outcomes, all-cause revisions, and tibial failures. RESULTS: At a mean follow-up of 5 years (range, 0.5 years to 12.8 years), there was not a statistically significant difference in clinical outcomes nor increased risk for all-cause revision or tibial failure in patients who had an mPTA <80°. Mean mPTA in patients who had tibial failures was 82.5° and not significantly different than those who did not have a tibial failure (82.9°) (P = .289). Tibial failure rate in knees with an mPTA <80° was 2.2% and not significantly different than knees with an mPTA ≥80° at 1.4% (P = .211). The all-cause revision rate in knees with an mPTA <80° was 5.8% and was not significantly different than knees with an mPTA ≥80° at 4.9% (P = .492). CONCLUSION: Patients who have tibia vara are not at increased risk for tibial related or all-cause failure in medial UKA. This data may allow surgeons to increase their indications for medial UKA.

Gradual Deformity Correction with a Computer-assisted Hexapod External Fixator in Blount's Disease.

Aim: To evaluate the results in terms of correction and complications from gradual correction with a computer-assisted hexapod circular external fixator in a mixed cohort of children with Blount's disease. Materials and methods: A retrospective review was performed of the correction and complications of 19 children (25 limbs) with recurrent infantile (IBD) and late-onset Blount's disease (LOBD) treated by gradual correction with a hexapod external fixator. The correction was measured by the medial proximal tibial angle (MPTA), anatomic posterior proximal tibial angle (aPPTA) and anatomic tibio-femoral angle (TFA). Obesity was present in 76% (19/25) of cases. Fifteen limbs were classified as infantile Blount's disease and 10 limbs as late-onset Blount's disease. The mean age was 12.5 years (range 7-17 years). Results: The mean pre-operative MPTA of 59° (SD 13°, range 33-79°) was corrected to a mean of 86° (SD 5°, range 77-93°). The mean pre-operative aPPTA of 64° (SD 14°, range 33-84°) was corrected to 79° (SD 6°, range 70-90°). The median pre-operative rotation of 15° internal rotation was corrected to normal (0-15° of external rotation). Eight out of 25 limbs had severe deformities with varus or procurvatum greater than 40° or both. The mean pre-operative TFA of 28° varus (SD 13°, range 4-53°) was corrected to 1.8° valgus (SD 6°, range 14° varus to 13° valgus). The median follow-up was 19 months (range 6-67 months). The alignment after correction was "good" in 55% (11/20), "acceptable" in 35% (7/20) and "poor" in 10% (2/20).The median duration for correction was 16 days (IQR 11-31 days, range 7-71 days). The median number of prescribed correction programmes was 1 (IQR 1-2, range 1-5). The mean total time in the frame was 136 days (SD 34 days, range 85-201 days).All patients developed minor pin track infections that resolved with oral antibiotics (Category 1 complications). Four patients developed complications that necessitated modification of the treatment plan (Category 2 complications). In two cases, treatment objectives could not be achieved (Category 3 complications). Two patients treated before skeletal maturity developed recurrent genu varum. Conclusion: Gradual correction with a computer-assisted hexapod external fixator may be a useful technique for correcting recurrent IBD or LOBD even in children with severe deformities. The results of gradual correction were similar in the two groups. While complications occur, most can be mitigated by timely intervention during the correction phase of treatment. Recurrence remains a concern if correction is performed before skeletal maturity. Level of evidence: 4. How to cite this article: Mare PH, Marais LC. Gradual Deformity Correction with a Computer-assisted Hexapod External Fixator in Blount's Disease. Strategies Trauma Limb Reconstr 2022;17(1):32-37.

Osteotomy treatments and post-operative fixations for Blount disease: A systematic review.

Background: Blount disease is a developmental abnormality characterized by abnormal ossification of proximal tibia, resulting in lower limb deformities with tibia vara. The condition worsens into knee deformity, gait abnormalities, and premature medial compartment osteoarthritis if left untreated. Managements of those deformities have also advanced in line with the understanding of the deformities. Without proper care management, they could lead into residual and translational deformities, increase of recurrence, and complicate the revision surgery. Methods: This study aims to enrich our understanding about the recent advances of treatments for Blount disease by reviewing 15 articles published with osteotomy surgeries and fixation methods. We also highlight many aspects of pre-operative assessment and planning, post-operative complications and recurrence, patients' follow-up, and overall satisfaction from patients' self-assessment. Results: The scope of this review is considered small but still covers various efforts to manage Blount diseases, including single-stage double osteotomy, grafting fibular fragments into tibia, two comparison studies, two unique case study, and experimental techniques to manage special cases requiring novel procedures. Conclusion: Careful surgical planning, acute or gradual correction options, and the use of fixator should be tailored to individual cases.

Prevalence of proximal tibia vara in Indonesian population with knee osteoarthritis.

Background: Proximal tibia vara has drawn interest since the concept of constitutional varus was introduced. Proximal tibia vara is a condition where the knee varus tilt the tibia condyle medially and shift the tibial articular surface medially. This condition affects medial proximal tibial angle measurements and the placement of the tibial implant in knee replacement surgery. Thus, it challenged the neutral knee arthroplasty alignment target because some people may present a proximal tibia vara. This study assesses the prevalence of the proximal tibia vara and the correlation to knee osteoarthritis grade. Methods: This retrospective study was carried out from January 2021 to June 2021. Eighty-five limbs were included with the following inclusion criteria: knee osteoarthritis patients who received a long view lower extremity radiograph. The exclusions criteria were (1) patients who had undergone arthroplasty and lower extremity surgery before and (2) valgus knee deformity. The outcomes in this study were HKAA, MAD, TAD, MPTA, PTRP, LDFA, and PTS. Intraclass correlation (ICC) using two-way mixed was used to assess the reproducibility of the radiographic parameters. Multiple logistic regression was used to evaluate the correlation between knee osteoarthritis grade and radiographs parameters (MAD and TAD). Result: A total 85 limbs from 52 patients were assessed in this study. Proximal tibia vara was found in 18 knees (21%.). The logistic regression was performed to assess the correlation between the severity of the knee osteoarthritis and radiographic parameters (MAD, TAD, LDFA, and PTS) with an overall p-value < 0.001 and pseudo-R2 = 0.29. Conclusion: A significant portion of patients with knee osteoarthritis have proximal tibia vara, and it is a pre-existing condition. Since the pre-existing proximal tibia vara affects preoperative measurements, a long-standing lower extremity x-ray is recommended to be obtained as part of knee replacement preparation.

Tibial reference point in total knee arthroplasty in patient with proximal tibia vara: A case report.

INTRODUCTION: Center of the intercondylar eminence at the proximal tibia had been widely used as a reference point for tibial bone cut in the Total Knee Arthroplasty (TKA) procedure. However, in the presence of preexisting tibia vara, the center of intercondylar eminence as tibial bone cut reference point often leads to varus malalignment after TKA procedure. CASE REPORT: 75 years old male patient complained of worsening pain on the left knee. The patient has had a history of knee osteoarthritis for the past seven years. The radiograph on the right knee revealed osteoarthritis grade 3 and left knee osteoarthritis grade 4, both with tibia vara. We planned to perform total knee arthroplasty surgery on his left knee with a preoperative planning tibial reference point of 10 mm lateral to the center. Six months after the knee replacement, there was minimal pain on activity, and full ROM was achieved on his left knee. On the radiographic X-ray evaluation, the alignment between the tibial implant surface and mechanical axis is 0.43 degrees valgus. CLINICAL DISCUSSION: In a varus knee malignment, the mechanical axis passes through one-third of the medial side of the knee, which makes the medial side of the implant wear off faster, resulting in the collapse of the medial tibia, thus decreasing implant survival and increasing the need for revision for TKA. CONCLUSION: In patients with preexisting tibia vara, tibial bone cut reference point planning before TKA procedure is important to provide longevity of implant survival and better quality of life.

Acute Correction and Plate Fixation for the Management of Severe Infantile Blount's Disease: Short-term Results.

PURPOSE: The purpose of this study is to evaluate the short-term results of lateral closing wedge osteotomy with medial hemiplateau elevation for the management of severe infantile Blount's disease. MATERIALS AND METHODS: In this prospective study, 11 cases of severe Blount's disease (Langenskiold stages five and six) were managed in the period between January 2017 and January 2020. Double osteotomy technique was applied, namely a metaphyseal closing wedge and a medial hemiplateau elevation, through a single midline incision. Fixation was achieved by a medial anatomical locked plate. Patients were evaluated clinically according to a modified version of paediatric outcomes data collection Instrument (PODCI) and radiologically by measuring the angle between the tibial and the femoral shaft, the mechanical axis deviation (MAD) and the angle of the medial tibial plateau (MTP) depression. RESULTS: The average follow-up period was 2 years. Healing of the osteotomies was achieved in all cases after the index operation within an average of 3 months. Based on our modification of the PODCI score, five cases had an excellent outcome, five were good, and one case ended with a fair outcome. No major complications were encountered in this study. CONCLUSION: The management of severe Blount's disease by acute correction using the aforementioned technique has been proven to achieve acceptable clinical and radiological outcomes without significant complications. LEVEL OF EVIDENCE: Level IV case series study. HOW TO CITE THIS ARTICLE: Nada AA, Hammad ME, Eltanahy AF, et al. Acute Correction and Plate Fixation for the Management of Severe Infantile Blount's Disease: Short-term Results. Strategies Trauma Limb Reconstr 2021;16(2):78-85.

Acute correction of severe complex adolescent late-onset tibia vara by minimally invasive osteotomy and simple circular fixation: a case series with 2-year minimum follow-up.

BACKGROUND: Despite multiple published reviews, the optimum method of correction and stabilisation of Blount's disease remains controversial. The purpose of this study is to evaluate the clinical and radiological outcomes of acute correction of late-onset tibial vara by percutaneous proximal tibial osteotomy with circular external fixation using two simple rings. Weighing up the pros and cons and to establish if this method would be the method of choice in similar severe cases especially in a context of limited resources. METHODS: This study was conducted between November 2016 and July 2020. We retrospectively reviewed the clinical notes and radiographs of 30 patients (32 tibiae) who had correction of severe late-onset tibia vara by proximal tibial osteotomy and Ilizarov external fixator. The mean age at the time of the operation was 16.6 (± 2.7) years (range 13-22). RESULTS: The mean proximal tibial angle was 65.7° (± 7.8) preoperatively and 89.8° (± 1.7) postoperatively (p < 0.001). The mean mechanical axis deviation improved from 56.2 (± 8.3) preoperatively to 2.8 (± 1.6) mm postoperatively (p < 0.001). The mean femoral-tibial shaft angle was changed from -34.3° (± 6.7) preoperatively to 5.7° (± 2.8) after correction, with degree of correction ranging from 25° to 45°. Complications included overcorrection (three cases 9%) and pin tract infection (eight cases 25%). The mean Hospital for Special Surgery knee scoring system (HSS) improved from 51.03 (± 11.24) preoperatively to 94.2 (± 6.8) postoperatively (p < 0.001). The mean length of follow up period 33.22 (± 6.77) months, (rang: 25-46 months). At final follow up, all patients had full knee range of motion and normal function. All cases progressed to union and there were no cases of recurrence of deformity. CONCLUSION: This simple procedure provides secure fixation allowing early weight bearing and early return to function. It can be used in the context of health care systems with limited resources. It has a relatively low complication rate. Our results suggest that acute correction and simple circular frame fixation is an excellent treatment choice for cases of late-onset tibia vara, especially in severe deformities.

[Congenital pseudarthrosis of the tibia : A rare often underestimated disorder]. / Kongenitale Pseudarthrose der Tibia : Ein seltenes, oft unterschätztes Krankheitsbild.

Congenital pseudarthrosis of the tibia (CPT) is a rare disease that has challenged trauma and orthopedic surgeons for a long time. Clinically CPT mostly presents with progressive varus and antecurvation malformation of the tibia in infancy and childhood. In many cases CPT is associated with neurofibromatosis or fibrous dysplasia. Without knowledge of the clinical picture a discontinuity of the tibia and/or fibula visible on an X­ray can be misinterpreted as a simple fracture. Histopathological investigations have revealed that a pathological alteration of the periosteum in the region of the pseudarthrosis, a hamartoma, may be essentially responsible for this disorder. Consequently, to treat the CPT a resection of the hamartoma must also be carried out. Multimodal treatment approaches combining pharmacological and surgical treatment, such as the cross-union technique of Paley, seem to have improved the prognosis of CPT.

Deformity Reconstruction Surgery for Blount's Disease.

Blount's disease is an idiopathic developmental abnormality affecting the medial proximal tibia physis resulting in a multi-planar deformity with pronounced tibia varus. A single cause is unknown, and it is currently thought to result from a multifactorial combination of hereditary, mechanical, and developmental factors. Relationships with vitamin D deficiency, early walking, and obesity have been documented. Regardless of the etiology, the clinical and radiographic findings are consistent within the two main groups. Early-onset Blount's disease is often bilateral and affects children in the first few years of life. Late-onset Blount's disease is often unilateral and can be sub-categorized as juvenile tibia vara (ages 4-10), and adolescent tibia vara (ages 11 and older). Early-onset Blount's disease progresses to more severe deformities, including depression of the medial tibial plateau. Additional deformities in both groups include proximal tibial procurvatum, internal tibial torsion, and limb length discrepancy. Compensatory deformities in the distal femur and distal tibia may occur. When non-operative treatment fails the deformities progress through skeletal maturity and can result in pain, gait abnormalities, premature medial compartment knee arthritis, and limb length discrepancy. Surgical options depend on the patient's age, weight, extent of physeal involvement, severity, and number of deformities. They include growth modulation procedures such as guided growth for gradual correction with hemi-epiphysiodesis and physeal closure to prevent recurrence and equalize limb lengths, physeal bar resection, physeal distraction, osteotomies with acute correction and stabilization, gradual correction with multi-planar dynamic external fixation, and various combinations of all modalities. The goals of surgery are to restore normal joint and limb alignment, equalize limb lengths at skeletal maturity, and prevent recurrence. The purpose of this literature review is to delineate basic concepts and reconstructive surgical treatment strategies for patients with Blount's disease.

Modified oblique high tibial osteotomy with minimal fixation for correction of adolescent tibia vara: a prospective case series study.

PURPOSE: To assess the reliability and efficacy of the modified oblique high tibial osteotomy for correction of complex deformity in adolescent tibia vara. METHODS: A total of 19 patients (25 legs) with adolescent tibia vara were enrolled in this study. There were 16 male (84.2%) and three female (15.8%) patients who had modified Rab oblique osteotomy with minimal fixation performed. The age of the patients at time of surgery ranged from 12 years to 30 years (mean 17.23 (sd 5.27)). The body mass index ranged from 22 kg/m2 to 42 kg/m2 (mean 32.05 (sd 6.13)). All patients were followed up for over two years (mean 3.4; 2 to 5). RESULTS: The femoro-tibial angle was improved from -34° to -12° (mean -20.04° (sd 5.24°) preoperatively and from -12° to 7°, postoperatively (mean 2.04° (sd 4.07)). Medial deviation of the mechanical axis corrected from 38 mm to 125 mm (mean 76.13 (sd 23.29)) preoperatively to 0 mm to 36 mm (mean 5.74 (sd 7.3)) postoperatively. The time needed to achieve union ranged from eight weeks to 16 weeks (mean 10.2 (sd 2.42)). According to the Lysholm functional knee score scale, there were 15 excellent (78.9%), two good (10.5%), one fair (5.2%) and one poor (5.2%) after correction of the deformity. CONCLUSION: Modified Rab osteotomy with minimal fixation by two or three screws shows promising results with good correction of varus deformity (coronal plane), internal torsion (axial plane) and procurvatum (sagittal plane), in management of adolescent tibia vara with minimal morbidity and complications. LEVEL OF EVIDENCE: IV.

Single-stage medial plateau elevation and metaphyseal osteotomies in advanced-stage Blount's disease: a new technique.

PURPOSE: Surgical treatment in advanced-stage infantile Blount's disease with medial plateau (MP) depression is challenging. Several osteotomies and fixation methods have been described with no established benchmark. We conducted this study to evaluate the efficacy and safety of a new single-stage technique for acute medial condyle elevation and metaphyseal osteotomies with internal fixation. METHODS: A prospective case series of 19 consecutive patients (21 knees) with severe infantile Blount's disease underwent a single-stage MP elevation and metaphyseal osteotomies, with internal fixation. The mean age was 10.3 years (8.2 to 13.6) and the mean follow-up was 5.1 years (3.2 to 8.3). The outcome measures included clinical and radiological parameters and patient-reported pediatric outcomes data collection instrument (PODCI) score. RESULTS: The mean PODCI score improved significantly from 50% to 88%. The mean internal tibial torsion improved from -27° to 11°. All cases maintained full knee extension, no limitation in flexion range of movement and no signs of instability or lateral thrust gait. All the radiographic parameters improved significantly; the mean tibiofemoral angle improved from -29° to 7°, the metaphyseal-diaphyseal angle improved from 33.4° to 4.7° and the angle of depressed MP improved from 38.3° to 2.4° (p < 0.001). At the latest follow-up, no cases of deformity recurrence were identified, the final limb-length discrepancy was < 1 cm in all patients. CONCLUSION: Single-stage MP elevation and metaphyseal osteotomies with internal fixation significantly improved the clinical and radiographic parameters and PODCI score in advanced infantile Blount's disease and precluded the use of external immobilization, with no evidence of deformity recurrence. LEVEL OF EVIDENCE: IV.

Tibia vara in Asians: Myth or fact? Verification with three-dimensional computed tomography.

BACKGROUND: There is a common perception among surgeons that Asian tibiae are significantly more varus compared to non-Asians, contributed both by an acute medial tibial proximal angle (MPTA) and diaphyseal bowing. Insight into the normative morphology of the tibia allows generation of knowledge towards disease processes and subsequently planning for corrective surgeries. METHODS: Computed tomography (CT) scans of 100 normal adult knees, aged 18 years and above, were analysed using a 3-dimensional (3D) analysis software. All tibiae were first aligned to a standard frame of reference and then rotationally aligned to the tibial centroid axis (TCAx) and the transmalleolar axis (tmAx). MPTA was measured from best-fit planes on the surface of the proximal tibia for each rotational alignment. Diaphyseal bowing was assessed by dividing the shaft to three equal portions and establishing the angle between the proximal and distal segments. RESULTS: The mean MPTA was 87.0° ± 2.2° (mean ± SD) when rotationally aligned to TCAx and 91.6° ± 2.7° when aligned to tmAx. The mean diaphyseal bowing was 0.1° ± 1.9° varus when rotationally aligned to TCAx and 0.3° ± 1.6° valgus when aligned to tmAx. The mean difference when the MPTA was measured with two different rotational alignments (TCAx and tmAx) was 4.6° ± 2.3°. No statistically significant differences were observed between males and females. Post hoc tests revealed statistically significant difference in MPTA between different ethnic sub-groups. CONCLUSION: The morphology of the proximal tibiae in the disease-free Asian knee is inherently varus but not more so than other reported populations. The varus profile is contributed by the MPTA, with negligible diaphyseal bowing. These implications are relevant to surgical planning and prosthesis design.

Predictors of early recurrence following high tibial osteotomy for infantile tibia vara.

AIMS: Recurrence of deformity following high tibial osteotomy (HTO) for infantile tibia vara (ITV) is common. The purpose of this study was to identify risk factors for recurrent deformity following HTO for ITV and to develop a simple scoring system to quantify the risk of recurrence in each patient. PATIENTS AND METHODS: We identified 69 patients with 102 affected limbs undergoing HTO for ITV from 2005 to 2015. Demographic and radiographic data was collected. On pre-operative radiographs, we measured the mechanical varus angle (MVA), the condyle shaft angle (CSA), the plateau depression angle (PDA), the metaphyseal-diaphyseal angle (MDA), and the mechanical lateral distal femoral angle (LDFA). On the post-operative radiographs, we measured the MVA and MDA only. We classified each limb according to the Langenskiold and LaMont classifications. Statistical analysis was performed to identify variables predictive of recurrent deformity, and these variables were analysed to develop a scoring system to quantify risk of recurrence following HTO. RESULTS: Of the examined variables, age older than 4.5 years, an MVA of more than 23° and a LaMont type C deformity were predictive of recurrent deformity. The incidence of recurrent deformity increased from 14.3% with no risk factors to 91.3% with three risk factors present. CONCLUSION: Advanced deformity and age above 4.5 years at the time of surgery predicts recurrent deformity following HTO for ITV. Surgery should be performed as soon as possible, and caregivers should be counselled appropriately regarding risk of recurrence and the need for future surgery.

Medial Metaphyseal Beak Angle as a Predictor for Langenskiöld Stage II of Blount's Disease.

OBJECTIVE: To determine the medial metaphyseal beak (MMB) cut-off angle predicting Langenskiöld stage II of Blount's disease and to study the intra-observer and inter-observer reliabilities of angle measurements and the influence of the experience level of observers. METHODS: A retrospective study was conducted on children aged 2-4 years from January 2000 to December 2017. Children were identified through a computer-based search. Children with Langenskiöld stage II of Blount's disease who had been initially evaluated at our institution were categorized into Blount group and children who were diagnosed with physiologic bowing were categorized into control group. Data on the patients' ages, genders, and affected sides were collected. The MMB angles were measured on standing anteroposterior radiographs of the knees. The angle was formed between one line drawn parallel to the medial cortex of the proximal tibia, and a second line running from the intersection of the first line with the proximal tibial metaphysis through to the most distal point of the MMB. Measurements were independently performed by six observers. All observers repeated the measurements 2 weeks after they were first done. RESULTS: There were 148 legs from 79 children (48 males and 31 females) with an average age of 28.6 months. The average MMB angle of the Blount group was 128.52° ± 5.38° (P-value <0.001) and of the control group was 114.45° ± 4.89°. The average femorotibial angle of the Blount group was 15.48° ± 6.81° (P-value <0.001) and of the control group was 7.71° ± 7.94°. The receiver operating characteristic curve showed that an MMB angle >122° (sensitivity 92.7%; specificity 97.0%) was associated with Langenskiöld stage II. The intraclass correlation coefficient of the intra-observer reliability ranged from 0.93-0.97, and the inter-observer reliability was 0.93. CONCLUSIONS: By using anteroposterior (AP) radiographs of the knee, the MMB angle is a potential radiographic parameter to distinguish between Langenskiöld stage II of Blount's disease and physiologic bowed legs, with an MMB angle >122° predicting Langenskiöld stage II.

Prognostic Reliability of a New Classification System for Blount's Disease.

Objective We conducted this study to evaluate the reproducibility of a new classification system for Blount's disease and assess its correlation with established radiological measures used to evaluate the severity of this disorder. Materials and Methods This is a retrospective review of children with Blount's disease that were younger than 10 years of age. Recurrence was defined as the need for a second corrective surgery. Radiographs immediately pre-surgery and at final follow-up were used to measure mechanical axis (MA), tibial metaphyseal-diaphyseal angle (TMDA), epiphyseal-metaphyseal angle (EMA), lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA). Patients were stratified according to the new classification (Type A, B, or C). Results Sixty-five limbs from 16 males and 24 females met our inclusion criteria. The average follow-up was 4.2 years. Twelve patients (with 22 Type-A extremities) underwent bracing with a success rate of 54%. Thirty-four patients (53 extremities) underwent surgical correction. The recurrence rate was 35.8%. Group C had a recurrence rate of 62%, higher than that of Group B (33%), and Group A (23%) (P = 0.026). In addition, irrespective of reoperation, patients in Group C had the least change in the MA (62%, P = 0.046) and the most severe values of MPTA and TMDA initially and after the operation (P < 0.05). Conclusion The new classification system for Blount's disease holds validity for predicting recurrence. The severity of the grades is correlated with the TMDA, MPTA, and varus reversibility. This can aid physicians and families in making an informed decision and setting treatment goals.