Physiological bowing and tibia vara. The metaphyseal-diaphyseal angle in the measurement of bowleg deformities

[Pediatric developmental disorders of the musculoskeletal system]

CLINICAL/METHODICAL ISSUE

In pediatric musculoskeletal disorders, a distinction is made between normal and abnormal development.

STANDARD RADIOLOGICAL METHODS

X‑ray examination is the standard diagnostic procedure.

METHODOLOGICAL INNOVATIONS

Cross-sectional imaging, such as magnetic resonance imaging (MRI), computed tomography (CT), and ultrasonography (US) are increasingly used.

PERFORMANCE

X‑ray imaging is still the examination method of choice but can be supplemented by cross-sectional imaging depending on clinical situation.

ACHIEVEMENTS

Cross-sectional imaging is helpful and necessary in many cases but significantly more time-consuming and costly than x‑ray examinations.

PRACTICAL RECOMMENDATIONS

Initially standard x‑rays should be taken, which can then be supplemented with cross-sectional imaging depending on the result and clinical question (MRI and US are preferred as there is no radiation).

Predicting Success of Deformity Correction With Tension Band Plating in Early-Onset Tibia Vara

BACKGROUND

Angular deformity correction with tension band plating has not been as successful in early-onset tibia vara (EOTV) as it has been in other conditions. Our hypothesis is that perioperative factors can predict the success of lateral tibial tension band plating (LTTBP) in patients with EOTV.

METHODS

A retrospective review was performed at 7 centers evaluating radiographic outcomes of LTTBP in patients with EOTV (onset <7 y of age). Single-event tibial LTTBP outcome was assessed through medial proximal tibial angle (MPTA). The final limb alignment following comprehensive limb growth modulation (CLGM), which could include multiple procedures, was assessed by mechanical axis zone (MAZone), mechanical tibio-femoral angle (mTFA), and mechanical axis deviation (MAD). Preoperative age, weight, deformity severity, medial physeal slope, and Langenskiöld classification +/- modification were investigated as predictors of outcome. Success was defined as the correction or overcorrection to normal age-adjusted alignment. The minimum follow-up was 2 years except when deformity correction, skeletal maturity, or additional surgery occurred.

RESULTS

Fifty-two patients with 80 limbs underwent 115 tibial LTTBP procedures at a mean age of 5.3 y, including 78 primary, 21 implant revisions, and 15 reimplantations for recurrence. Tibial LTTBP resulted in a mean change of +8.6 o in MPTA and corrected 53% of tibias. CLGM resulted in MAD correction for 54% of limbs.Univariate analysis showed that success was best predicted by preoperative age, weight, MPTA, and MAD. Multivariate analysis identified that preoperative-MPTA/MAD and preoperative-weight<70 kg were predictive of MPTA and MAD correction, respectively. The probability of success tables are presented for reference.

CONCLUSION

Successful correction of MPTA to age-adjusted norms following a single-event LTTBP occurred in 53% of tibias and was best predicted by preoperative-MPTA and preoperative body weight <70 kg. Comprehensive growth modulation corrected limbs in 54%. The probability of correction to age-adjusted MAD is best estimated by preoperative-MAZone 1 or 2 (MAD ≤40 mm). Limbs with preoperative-MAD>80 mm improved, but ultimately all failed to correct completely with CLGM. Osteotomy may need to be considered with these severe deformities. While modified Langenskiöld classification and medial physeal slope have been shown to predict the outcome of osteotomy, they were not predictive for LTTBP. Change in MPTA was common after physeal untethering.

LEVEL OF EVIDENCE

Level-III.

Normal Reference Values of the Blackburne-Peel Ratio for Measuring Patellar Height in an Indian Population

Background Historically, the quadriceps tendon has the largest sesamoid bone of the body, which is known as the patella. Patellar height is one of the important parameters in assessing patellar stability. The patella height has been found to vary in several diseases. As a result, ratios based on a variety of patellar bone indices are used to determine the norms. This study aimed to determine the typical patella height ratio in Indians, who have different sitting and squatting positions as opposed to Caucasians, by applying the Blackburne-Peel ratio to assess patellar height which is an alternative to the conventional Insall-Salvati ratio. Methodology A total of 100 normal lateral knee radiographs from the Indian population were used in this retrospective study. The Blackburne-Peel method (A/B) was used to calculate the ratios. It was calculated as perpendicular length measured from the inferior articular point of the patella to the point perpendicular (A) to the tibial plateau to the length of the articular surface of the patella (B). Results Patella height ratio for men was 0.67 ± 0.01, whereas, for women, it was 0.67 ± 0.02. The ratio did not differ significantly (p > 0.05) from the Western population. Conclusions The normal range of the Blackburne-Peel ratio for the Indian population was established, which can be used as a baseline and can be helpful in establishing patellar height in the Indian population. Similar to previous studies, our study shows that patella height ratios are stable regardless of gender or race and can be used to enhance and restore knee kinematics and functions.

A Predictive Score for Infantile Blount Disease Recurrence After Tibial Osteotomy

INTRODUCTION AND OBJECTIVE

Several predictive factors for infantile Blount disease recurrence after tibial osteotomy were discovered. This study aimed to examine and utilize various predictors to develop a prediction score for infantile Blount disease recurrence after tibial osteotomy.

METHODS

We conducted a retrospective cohort study of infantile Blount disease patients who underwent tibial osteotomy between January 1998 and December 2020. Potential predictors, including clinical and radiographic parameters, were examined for their association with the disease recurrence after receiving tibial osteotomy. A predictive score was subsequently developed based on those potential predictors through multivariable logistic regression modeling.

RESULTS

A total of 101 extremities diagnosed with infantile Blount disease from 58 patients who underwent tibial osteotomy were included. Of those, 15 extremities (14.9%) recurred. Univariable logistic regression analysis identified age older than 42 months [odds ratio (OR)=4.28; P =0.026], Langenskiöld classification stage III (OR=9.70; P <0.001), LaMont classification type C (OR=15.44; P <0.001), preoperative femorotibial angle <-14 degrees (OR=4.21, P =0.021), preoperative metaphyseal-diaphyseal angle >16 degrees (OR=8.61, P =0.006), preoperative medial metaphyseal slope angle >70 degrees (OR=7.56, P =0.001), and preoperative medial metaphyseal beak angle >128.5 degrees (OR=13.46, P =0.001) as potential predictors of infantile Blount disease recurrence after tibial osteotomy. A predictive score comprised of age younger than 42 months, LaMont classification type C, and medial metaphyseal beak angle >128 degrees demonstrated an excellent predictive performance (area under the receiver operating characteristic curve =0.87), good calibration, and high internal validity.

CONCLUSIONS

Our developed predictive score accurately predicted infantile Blount disease recurrence after tibial osteotomy. The results from our developed prediction tool allow physicians to inform prognosis, increase awareness during the follow-up period, and consider additional interventions to prevent disease recurrence.

LEVEL OF EVIDENCE

Level II.

Single-Stage Tibial Osteotomy for Correction of Genu Varum Deformity in Children

Conservative and operative treatments with gradual or acute correction of severe varus deformities of the leg have been described. We evaluated whether the corrective osteotomy used within the NGO Mercy Ships is an effective treatment for genu varum deformity of different etiologies in children and which patient specific factors have an influence on the radiographic outcome. In total, 208 tibial valgisation osteotomies were performed in 124 patients between 2013 and 2017. The patients' mean age at the time of surgery was 8.4 (2.9 to 16.9 (min/max)) years. Seven radiographically measured angles were used to assess the deformity. Clinical photographs taken pre- and postoperatively were assessed. The mean time between the surgery and the end of physiotherapeutic treatment was 13.5 (7.3 to 28) weeks. Complications were monitored and classified according to the modified Clavien-Dindo-classification system. The mean preoperative mechanical tibiofemoral angle was 42.1° varus (range: 85°-12° varus). The mean postoperative mechanical tibiofemoral angle was 4.3° varus (range: 30° varus-13° valgus). The factors predicting a residual varus deformity were higher age, greater preoperative varus deformity and the diagnosis of Blount disease. The tibiofemoral angle measured on routine clinical photographs correlated well with the radiographic measurements. The single-stage tibial osteotomy described is a simple, safe and cost-effective technique to correct three-dimensional deformities of the tibia. Our study shows very good mean postoperative results, but with a higher variability than in other studies published. Nevertheless, considering the severity of preoperative deformities and the limited opportunities for aftercare, this method is excellent for the correction of varus deformities.

Guided Growth for Varus Deformity Following Early Tibial Osteotomy in Infantile Tibia Vara-A Multi-Center Study

BACKGROUND

Despite early osteotomy, many patients with infantile tibia vara (ITV) have persistent or recurrent varus deformity and disordered growth at the medial proximal tibial physis. Our hypothesis was that lateral tibial tension band plating (LTTBP) could guide correction.

METHODS

A retrospective review at 6 centers of 15 patients (16 extremities) was performed of LTTBP for varus deformity following early osteotomy in ITV, diagnosed≤4years of age. Correction of deformity parameters on digital standing anteroposterior lower extremity radiographs determined outcome.

RESULTS

Twenty-two LTTBP procedures were performed at mean age of 7.5 years, including 4 revisions for implant failure and 2 reimplantations for recurrence. Single event LLTBP, improved the medial proximal tibial angle with a mean change of 13.4 degrees (0.39 degrees/month). Eleven limbs had preoperative mechanical lateral distal femoral angle (mLDFA)>90 degrees. While n degree femoral procedures were performed, at study end, 11 femurs had mechanical lateral distal femoral angle≤90°. Pretreatment, 13 extremities had mechanical axis zone (MAZone) III varus (81%) and 3 had MAZone II varus (19%). LTTBP's were able to initially correct 13 limbs to MAZone I or valgus but 4 limbs rebounded to MAZone II varus after implant removal. Final limb alignment, after all surgeries and rebound, included 9 in MAZone I, 5 in MAZone II varus and 2 in MAZone III varus. Average follow-up was 3.0 years at mean 10.7 years of age. Fifteen procedures resulted in improvement in MAZone and 7 had no change. On average, those that improved were younger (7.3 vs. 8.0 y), weighed less (45.5 kg with body mass index 26.5 kg/m 2 vs. 67.8 kg and body mass index 35.7 kg/m 2 ), had lower mechanical axis deviation (37.1 mm vs. 43.9 mm), lower medial physeal slope (61.7 vs. 68.7 degrees) and had a higher percentage of open triradiate phases (87 vs. 57%).

CONCLUSIONS

LTTBP for residual varus, after initial osteotomy in ITV, resulted in 81% of limbs initially achieving MAZone I or valgus with implant failure revisions and femoral remodeling. Rebound after implant removal reduced the corrected rate to 56%. Ninety-four percent avoided osteotomy during the study period.

LEVEL OF EVIDENCE

IV.

Comparative Evaluation of the Radiographic Parameters for Screening Early Blount Disease

BACKGROUND

Radiographic findings in young children with physiological bowing sometimes difficult to distinguish from early Blount disease. However, early diagnosis of the disease is critical because of the poor treatment outcomes for Blount disease. In this study, we aim to evaluate the accuracy of the metaphyseal-diaphyseal angle (MDA) compared with the medial metaphyseal beak (MMB) angle for differentiating between physiological bowing and early Blount disease and to determine which parameter to adequately screen for the subsequent development of Blount disease.

METHODS

A retrospective study was conducted on children aged 1 to 3 years old who were brought to our outpatient clinic with bowed leg between 2000 and 2017. Data on the patients' age, sex, and affected sides were collected. Radiographic measurements of the femorotibial angle (FTA), MDA, and MMB angle were evaluated from the initial radiographs. An observer repeated the measurements on all the radiographs 2 weeks after they were first done.

RESULTS

In total, 158 legs were considered from 79 children (48 males/31 females), whose average age was 26.0±6.1 months old. Eighty-seven legs were diagnosed with Blount disease and 71 legs had physiological bowing. Using single cutoff values of 16 degrees for the MDA showed low sensitivity (50.6%), very high specificity (100.0%), and a very high positive predictive value (PPV); while using MMB angle cutoff values ≥122 degrees showed very high sensitivity (92.0%), high specificity (80.3%), and a high PPV. Considering the MDA and MMB angle simultaneously showed very high sensitivity (93.1%), high specificity (80.3%), and a high PPV. The area under the receiver operating characteristic curve of the MDA and MMB showed excellent (0.89) and outstanding (0.93) discriminative ability, respectively. When combining the MDA and MMB angles, it was also considered outstanding performance (area under the receiver operating characteristic curve=0.95).

CONCLUSIONS

The MMB angle represents a potential radiographic screening parameter for predicting early Blount disease in children 1 to 3 years old, offering high sensitivity and specificity. The MDA showed excellent specificity as a confirmation parameter for Blount disease patients. Applying both the MDA and MMB angles is another option to increase early recognition and confirm the diagnosis in early Blount disease patients.

LEVEL OF EVIDENCE

Level II.

Guided growth using a tension-band plate in Blount's disease

Our observational study's objective was to determine how effective guided growth with tension-band plates was to correct the deformity in Blount's disease. We reviewed the records of 14 children (18 limbs) with Blount's disease who were treated with tension-band plates as the only surgical intervention at a single institution over eight years. Five children (seven limbs) had infantile Blount's disease with Langenskiöld stage ≤2. Nine children (11 limbs) had late-onset Blount's disease. The mean age at operation was 7.2 years (SD, 3.1, range, 2.9-11.8). The tension-band plate effectively corrected the varus deformity in 78% (14/18) of limbs. Correction to normal mechanical alignment was achieved in 67% (n = 12) of limbs at a mean of 18 months (SD, 7, range, 9-31). Failure to achieve correction of the mechanical axis was due to delayed implant removal and overcorrection in 11% (2/18), mechanical failure due to screw fixation failure in 11% (2/18) and in 6% (1/18) due to a misplaced epiphyseal screw. There was a greater magnitude of correction in the Infantile Blount's disease group (mean, 26°, SD, 9°) when compared to the children with late-onset Blount's disease (13°, SD, 4°) (P = 0.021). The mean correction rate was 1.8°/month in the Infantile Blount's disease group and 0.7°/month in the late-onset Blount's disease group, respectively (P = 0.014). Our findings support the use of tension-band plating in Blount's disease. Further research is required to determine the ideal indications and to investigate the long-term outcome of guided growth in Blount's disease. Level of evidence: Level 4.

Knee measurements among children with normal alignment, physiologic and pathologic bowing aged 0-3 years old: a systematic review

Distinguishing physiologic and pathologic genu varus is challenging among children below age 3. They can be assessed by measuring intercondylar distance (ICD), clinical tibiofemoral angle (cTFA) or radiologic TFA (rTFA). We aim to determine the knee measurement values among three groups of children. Medline (1946-) and EMBase (1947-) were searched until 31 July 2020 using a search strategy. Studies with original data which reported knee measurements among children with normal alignment, physiologic and pathologic bowing between the ages of 0-3 years were included. In total 1897 studies were identified, and 16 studies included after title and abstract screening. These studies involved 1335 patients with normal alignment, 286 with physiologic and 184 with pathologic bowing. Five studies provided data on ICD, seven on cTFA and eight on rTFA which were pooled for meta-analyses. Normal children had neither measurable ICD nor demonstrable varus on cTFA after 19 months old. The mean (95% confidence interval) ICD for children with pathologic genu varus at 18 months was 4.41 (4.19-4.63). The rTFA for children with pathologic compared to the physiologic bowing by age groups was; 11-20 months: 24.74°(23.22°-26.26°) vs. 19.44°(17.05°-21.84°), 21-30 months: 20.35°(18.13°-22.56°) vs. 14.72°(12.32°-17.12°) and 12-36 months: 32.60°(26.40°-38.80°) vs. 19.14°(17.78°-20.50°). Children above the age of 18 months with genu varus should be closely monitored clinically using ICD or cTFA. An ICD of more than 4 cm may warrant further investigation for pathologic cause. rTFA has limited use in the detection of pathologic varus.

Co-occurrence of Blount's disease and Legg-Calvé-Perthes disease: is obesity a factor?

Legg-Calvé-Perthes disease (LCPD) and Blount's disease share a similar presenting age in addition to similar symptoms such as limp or knee pain. A little overlap is mentioned about both diseases. We sought to present cases of children having both conditions to discuss the implications of this co-occurrence on diagnosis and management. After institutional review board approval, we retrospectively reviewed records of four children who developed both Blount's disease and LCPD. Patient details and outcomes were analyzed. Radiographs were evaluated for the lateral pillar classification, Stulberg classification, tibial metaphyseal-diaphyseal angle and tibiofemoral angle. Two of the cases were initially diagnosed with Blount's disease and subsequently developed Perthes, one case presented initially with both disorders and the final case had Perthes followed by Blount's. Three children were obese and one was overweight. The common symptom to all patients was an abnormal gait, which was painless in two children and painful in two. Blount's disease required surgery in three children. Radiographs showed Lateral Pillar B, B/C border and C hips, and the final Stulberg was stage II (n = 2) or stage IV (n = 2). Obesity is associated with Blount's disease and LCPD, so obese children can be at an increased risk of developing both disorders. Therefore, a child with Blount's disease who has persistent, recurrent or worsening symptoms such as gait disturbance or thigh or knee pain might benefit from a careful physical exam of the hips to prevent a delayed or even missed LCPD diagnosis.

Using Combinations of Both Clinical and Radiographic Parameters to Develop a Diagnostic Prediction Model Demonstrated an Excellent Performance in Early Detection of Patients with Blount's Disease

Early identification of pathological causes for pediatric genu varum (bowlegs) is crucial for preventing a progressive, irreversible knee deformity of the child. This study aims to develop and validate a diagnostic clinical prediction algorithm for assisting physicians in distinguishing an early stage of Blount’s disease from the physiologic bowlegs to provide an early treatment that could prevent the progressive, irreversible deformity. The diagnostic prediction model for differentiating an early stage of Blount’s disease from the physiologic bowlegs was developed under a retrospective case-control study from 2000 to 2017. Stepwise backward elimination of multivariable logistic regression modeling was used to derive a diagnostic model. A total of 158 limbs from 79 patients were included. Of those, 84 limbs (53.2%) were diagnosed as Blount’s disease. The final model that included age, BMI, MDA, and MMB showed excellent performance (area under the receiver operating characteristic (AuROC) curve: 0.85, 95% confidence interval 0.79 to 0.91) with good calibration. The proposed diagnostic prediction model for discriminating an early stage of Blount’s disease from physiologic bowlegs showed high discriminative ability with minimal optimism.

Controlled Double Gradual Opening Osteotomy for the Treatment of Severe Varus of the Knee-Blount's Disease

Varus deformity of the knee can lead to early degeneration of the medial tibiofemoral joint. Pediatric patients can be pathologically affected with this deformity known as Blount disease. The cause of this pathology is still uncertain, but some risk factors are well established, such as obesity and family history. The diagnosis is made through clinical history, physical examination, and the radiographic analysis after the age of 2.5 years. The analysis of the metaphyseal-diaphyseal angle, described by Levine and Drennan, is also commonly used for prognosis. When this angle is greater than 16°, it is considered to be grossly abnormal. Possible options for correcting the generated angular deformity are epiphysiodesis, osteotomy (acute or gradual correction), and gradual correction by distraction of the physis. In this surgical technique, we performed a double tibial osteotomy with controlled gradual opening using monolateral external fixator (Orthofix, Verona, Italy). Our technique proved to be an effective way to correct the adolescent tibia vara and is practical and reproducible. Moreover, the use of gradual opening osteotomy allowed a more accurate outcome.

Alkaline phosphatase in pediatric patients with genu varum caused by vitamin D-deficient rickets

An elevated serum alkaline phosphatase (ALP) level is one of the markers for the presence of rickets in children, but it is also associated with bone formation. However, its role in diagnosing genu varum in pediatric patients with vitamin D-deficient rickets is still unknown. To clarify the role of the serum ALP level in assessing the severity of genu varum, we retrospectively investigated this issue statistically using data on rickets such as serum intact parathyroid hormone (iPTH), 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, ALP, the level of creatinine as the percentage of the median according to age (%Cr), and the metaphyseal diaphyseal angle (MDA) in the lower extremities as an index of the severity of genu varum. A multiple regression analysis revealed that log ALP and %Cr values were negatively associated with MDA values. The former association was also confirmed by a linear mixed model, while iPTH was positively associated with MDA by path model analysis. To elucidate the association of ALP with MDA in the presence of iPTH, we investigated three-dimensional figures by neural network analysis. This indicated the presence of a biphasic association of ALP with MDA: the first phase increases while the second decreases MDA. The latter phenomenon is considered to be associated with the increase in bone formation due to the mechanical stress loaded on the lower extremities. These findings are important and informative for pediatricians to understand the significance of the serum ALP level in pediatric patients with genu varum caused by vitamin D deficiency.

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.

Acute correction of proximal tibial coronal plane deformity in small children using a small monolateral external fixator with or without cross-pinning

PURPOSE

Surgical correction of proximal tibia deformity in small children can be challenging. We present the surgical technique and outcome of proximal tibia osteotomy fixed with small monolateral external fixator in this patient group.

METHODS

A total of 17 cases in eight patients younger than nine years of age were study subjects. A proximal tibia osteotomy was fixed with a small monolateral external fixator with or without cross-pinning. Outcome was evaluated by changes of radiographic parameters such as medial proximal tibia angle (MPTA), metaphyseal diaphyseal angle (MDA) and clinical findings of complications, time interval until weight bearing and fixator removal time.

RESULTS

MPTA improved from a preoperative mean of 73° (sd 4°; 66° to 78°) to an immediate postoperative mean of 90° (sd 3°; 85° to 96°) in varus tibiae, and from 104° (sd 1°; 103° to 105°) to 89° (sd 1°; 88° to 89°) in valgus tibiae. In all, 15 of the 17 cases (88.3 %) achieved postoperative MPTA within the normal range (85° to 90°). MDA improved from a preoperative mean of 19° (sd 5°; 11° to 24°) to an immediate postoperative mean of 0° (sd 4°; -6° to 7°) in varus tibiae, and from -25° (sd 2°; -22° to -24°) to 2° (SD 1°; 1° to 3°) in valgus tibiae. Full weight bearing was possible at mean 1.7 months (0.5 to 3.0). Mean follow-up period was 6.5 years (sd 5.4; 1.0 to 16.0). No complications developed during the follow-up.

CONCLUSION

Proximal tibia osteotomy fixed with small monolateral external fixator provides accurate, safe and efficient correction in the management of coronal plane angular deformity in small children.

LEVEL OF EVIDENCE

Level IV.

Blount disease and familial inheritance in Ghana, area cross-sectional study

Objective

The objective of this study is to study familial inheritance for Blount disease to create better understanding of the aetiology of Blount disease.

Methods

After reviewing patient files and conventional roentgenologic imaging, 139 patients with Blount disease were included in this cross-sectional study, of which 102 patients were interviewed. During the interviews, patient characteristics and family history were collected. Blood samples were taken from five patients and three families and a whole exome sequencing was performed.

Results

Although patients came from all over the country, 90% of the patients belonged to the Akan tribe. A positive family history was found in 63 families (62%), of which, almost two-third had a positive family history in a first-degree family member. In most of the cases (64%), the varus legs resolved over time. In 9%, severe bowing remained 'just like the patient'. The results of the whole exome sequencing did not show a genetic predisposition.

Conclusion

This study describes a large group of Blount patients. Because of the high numbers of positive family history and the centralisation of patients in the Akan region, a familial predisposition is suggested. Further genetic research is essential for better understanding of the possible multifactorial aetiology in Blount disease.

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.

Predictive Factors for Recurrence in Infantile Blount Disease Treated With Tibial Osteotomy

BACKGROUND

This study aimed to determine the recurrence rate in infantile Blount disease (IBD) in a cohort of patients treated with a tibial osteotomy; and also to identify which factors were associated with recurrence.

METHODS

We reviewed the records of 20 patients, under the age of 7 years, with IBD (35 involved extremities) treated by proximal tibial realignment osteotomy to physiological valgus at a single institution over 4 years. We then analyzed the data to determine the rate of recurrence and identify the risk factors for recurrence.

RESULTS

The mean age of the included patients was 4.2 years (range, 2 to 6 y). We observed a recurrence rate of 40% (n=14) at a mean follow-up of 42 months (range, 21 to 72 mo). Knee instability [odds ratios OR, 6.6; 95% confidence interval (CI), 2.0-22.2], Langenskiöld stage (OR, 6.3; 95% CI, 2.0-19.4), and severity of the deformity, as measured by medial physeal slope (MPS) (OR, 1.2; 95% CI, 1.1-1.4), were associated with recurrence. On multiple logistic regression analysis, MPS remained the most relevant predictor of recurrence. Receiver operating curve analysis showed that an MPS ≥60 degrees predicted recurrence with a sensitivity of 79% and specificity of 95% (area under the curve=0.925). Postoperatively, increased varus alignment on weight-bearing as measured by the tibio-femoral angle was indicative of knee instability and associated with increased odds of recurrence (OR, 1.5; 95% CI, 1.1-1.9; P=0.004).

CONCLUSIONS

We observed a recurrence rate of 40% in children with IBD under 7 years treated with acute correction to a tibio-femoral angle of 5 to 10 degrees valgus through a dome proximal tibial osteotomy. Knee instability, Langenskiöld stage, and MPS were associated with recurrence. Cases with an MPS ≥60 degrees seem to be particularly at risk for recurrence. Further research is needed to validate these findings.

LEVEL OF EVIDENCE

Level IV.

Genu varum and football participation: Does football participation affect lower extremity alignment in adolescents?

BACKGROUND

Genu varum is one of the most common anatomical variations of knee alignment which is considered a risk factor for anterior knee pain and anterior cruciate ligament injury among football players. Considering that millions of children participate in high-level football training, the purpose of this study was to determine the genu varum development in adolescent football players and non-athlete peers. The hypothesis of this study was that genu varum incidence was higher in adolescent football players compared with non-athletic peers.

METHODS

The design was a cross-sectional study. Two-hundred and thirty-seven male football players (FG) and aged-matched and anthropometrically similar non-athletes (CG) were recruited into the study. The quadriceps angle and intercondylar-intermalleolar distance were measured to evaluate the leg alignment. The distance between the medial edges of the condyles and malleoli was measured in millimeters using a digital caliper while angle measurements were performed using a photographic technique in a standing position. To analyze the variables, comparison, correlation and regression statistical tests were performed.

RESULTS

The intercondylar-intermalleolar distance and quadriceps angle values were significantly higher in FG than CG in all ages. In FG, a very strong correlation was found between number of training years and the intercondylar-intermalleolar distance. The prevalence of genu varum was markedly higher in FG than CG (~37% vs. 2%, respectively) based on intercondylar-intermalleolar distance.

CONCLUSION

This study determined that the prevalence of genu varum and abnormal quadriceps angles in adolescent football players is significantly higher compared with their non-athletic peers.

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.

Improved Gait Parameters After Orthotic Treatment in Children with Infantile Tibia Vara

The aim of this study was to investigate the modification of gait kinematics before and after orthotic treatment in patients with ITV. Vicon instrumented gait analysis was performed on three patients with ITV, pre and post treatment. Orthoses were applied a total of eighteen participants with ITV who were 25-38 months. 34 extremities were treated and radiographic evidence evaluated before and after orthotic treatment. Treatment duration for orthotic treatment ranged between 11 and 41 (25.9 ± 10.0) months. Only three patients were evaluated in gait analysis due to application difficulties. Three patients kinematic and kinetic instrumented gait analysis were found flatfoot, varus and internal rotation of the foot, hip flexion and external rotation. Study were reported an improvement in gait kinematics after orthotic treatment, in patients with ITV.

Physiologic Leg Bowing is not a Physiologic Condition but Instead is Associated with Vitamin D Disorders in Toddlers

When children around 2-year-old show leg bowing without lower-limb radiographic abnormalities for rickets, the leg bowing is classified as "physiologic" genu varum without conducting a blood test. However, it has recently been suggested that toddlers who are diagnosed with physiologic genu varum may in fact have some form of bone metabolic disorder. In this 1:2 case-control study, blood samples were obtained from 33 toddlers with genu varum without radiographic abnormalities for rickets and 66 age- and gender-matched healthy children. Serum alkaline phosphatase (sALP), intact parathyroid hormone (siPTH), 25-hydroxy vitamin D [s25(OH)D], calcium (sCa), and inorganic phosphate (sP) were measured. s25(OH)D of the subjects with genu varum (24.8 ng/ml) were significantly lower than those of the control (33.6 ng/ml) (p < 0.001). The frequency of vitamin D insufficiency/deficiency (< 20 ng/ml) of the subjects with genu varum (39%) was significantly higher than that in the control (14%) (p = 0.004) (odds ratio by vitamin D insufficiency/deficiency: 4.1 [1.5-11.1, p = 0.004]). sCa in subjects with genu varum (10.2 ng/ml) were significantly higher than in control (9.8 ng/ml) (p < 0.001), as were sALP (1057 IU/l) and siPTH (28.4 pg/ml) (740 IU/l and 8.8 pg/ml in control, respectively; p < 0.001). siPTH levels were associated with s25(OH)D levels in subjects with genu varum (r = - 0.57, p < 0.001), while no association was observed in the control (r = 0.11, p = 0.36). Genu varum without radiographic abnormalities of rickets was associated with both vitamin D and bone-metabolic disorders in toddlers, indicating that physiologic genu varum is not a physiologic condition in toddlers.

Medial Metaphyseal Slope as a Predictor of Recurrence in Blount Disease

OBJECTIVE

This study was aimed to find the radiographic parameter predicting recurrence of stage 2 Blount's disease.

METHOD

We retrospectively reviewed radiographs of 82 legs from 49 patients diagnosed with stage 2 Blount's disease by Langenskiöld classification who had failed brace treatment and underwent valgus osteotomy between 1998 to 2016. Age ranged from 26 to 47 months. The metaphyseal-diaphyseal angle was measured preoperatively. The medial metaphyseal slope of the proximal tibia and femorotibial angle were measured preoperatively and 3, 6, 12, and 24 months postoperatively in both non-recurrence (group 1) and recurrence (group 2) group. The receiver operating characteristic curve calculated using MedCalc software was used to determine the medial metaphyseal slope predicting risk for recurrence. Statistical analysis was performed using SPSS software.

RESULTS

The mean follow-up time was 4.83 ± 0.38 years. The mean age was 34.57 ± 5.76 in group 1 and 33.2 ± 1.48 in group 2 (P = 0.258). The mean preoperative metaphyseal slope was 62.39° ± 9.75° in group 1 and 73.22° ± 6.59° in group 2 (P = 0.02). The mean preoperative femorotibial angle (FTA) was -14.31° ± 8.25° in group 1 and -18.89° ± 7.74° in group 2 (P = 0.1). The mean preoperative metaphyseal diaphyseal angle (MDA) was 14.75° ± 4.21° in group 1 and 20.11° ±5.16° in group 2 (P = 0.001). Demographic data including age, gender, weight, height, and body mass index showed no statistically significant difference between both groups. Out of 82 legs, 9 (10.97%) had recurrence. Preoperatively, the metaphyseal-diaphyseal angle showed statistical significance between both groups. The medial metaphyseal slope showed statistically significant difference between group 1 and group 2 at 3, 6, 12, and 24 months postoperatively. The receiver operating characteristic curve showed that a medial metaphyseal slope more than 70° at 12 months (sensitivity 88.89% and specificity 69.86%) and more than 62° at 24 months postoperatively (sensitivity 100%, specificity 52.3%) was a predictor for recurrence of stage 2 Blount's disease.

CONCLUSION

Medial metaphyseal slope more than 62° over the 24-month follow-up was associated with recurrence of varus deformity.

A comparative evaluation of tibial metaphyseal-diaphyseal angle changes between physiologic bowing and Blount disease

The purpose of this study was to estimate the rate of spontaneous improvement in tibial metaphyseal-diaphyseal angle (TMDA) in physiologic bowing in comparison to that in Blount disease and to provide reference values of TMDA for monitoring patients with highly suspected to have Blount disease.We retrospectively reviewed patients with physiologic bowing meeting the following criteria:(1) TMDA greater than 9° before 36 months of age at initial evaluation;(2) two or more standing long bone radiographs available; and(3) follow-up conducted up to resolution of deformity.Patients with Blount disease had(1) more than 2 standing long bone radiographs obtained before 36 months of age and(2) underwent no treatment during the period in which these images were obtained.TMDA measurements were obtained from 174 patients with physiologic bowing and 32 patients with Blount disease. Rates of TMDA improvement were adjusted by multiple factors using a linear mixed model, with sex and laterality as fixed effects and age and individual patients as the random effects.In the physiologic bowing group, TMDA improved significantly, by 3° per 6 months and by 6° per year. Changes in TMDA were not significant in the Blount disease group.Knowing the rate of TMDA change can be helpful for physicians seeking to monitor infants with suspected as having Blount disease with a high TMDA and to avoid unnecessary repeat radiographic evaluations.

Blount disease

Blount disease is an asymmetrical disorder of proximal tibial growth that produces a three-dimensional deformity. Tibia vara is the main component of the deformity. Blount disease exists as two clinical variants, infantile or early-onset, and adolescent or late-onset, defined based on whether the first manifestations develop before or after 10 years of age. The pathophysiological mechanisms are unclear. In the Americas and Caribbean, Blount disease chiefly affects black obese children. Without treatment, the prognosis is often severe, particularly in the infantile form due to the development of medial tibial epiphysiodesis at about 6 to 8 years of age. In other parts of the world, the associations with black ethnicity and obesity are less obvious and the prognosis is often less severe. A consensus exists about the optimal treatment in two situations: before 4 years of age, progressive Blount disease should be corrected, preferably by a simple osteotomy; and once medial tibial epiphysiodesis has developed, both a complementary epiphysiodesis and gradual external fixator correction of the other alignment abnormalities, rotational deformity, and limb length are required. After 4 years of age, the outcome in the individual patient is difficult to predict. Magnetic resonance imaging supplies information on the morphology and vascularisation of the growth regions, thereby helping to guide treatment decisions. In the adolescent form, morbid obesity limits the treatment options. Untreated Blount disease in adults is rarely encountered. A more common occurrence is the presence of residual abnormalities at skeletal maturity in patients treated for Blount disease in childhood. Premature osteoarthritis may develop. In this situation, osteotomy may delay the need for total knee arthroplasty.

Recurrence After Surgical Intervention for Infantile Tibia Vara: Assessment of a New Modified Classification

BACKGROUND

To propose a modified classification of infantile tibia vara based on the morphology of the metaphyseal/epiphyseal tibial slope that better correlates with treatment outcomes than the traditional Langenskiold classification.

METHODS

We performed a retrospective review of 82 patients and 115 limbs that underwent surgery for infantile tibia vara over a 22-year period (1990 to 2012) at a single institution. A modified Langenskiold classification was applied to all patients preoperatively and the outcomes were assessed. The modified system created a 3-stage classification (types A, B, and C): type A has a partially lucent medial metaphyseal defect, with or without "beaking"; type B deformity has downward-sloping curvature of the lateral and inferior rim of a completely lucent metaphyseal defect, which then has an upslope at the medial rim, resembling a ski-jump, with no epiphyseal downward slope; type C has vertical, downsloping deformity of both the epiphysis and metaphysis, with no upward curvature projecting medially at the inferior extent, while the epiphysis slopes downward into the metaphyseal defect.

RESULTS

Sixty-seven limbs did not develop recurrence following corrective osteotomy, whereas 48 limbs required at least 1 repeat surgery for recurrent deformity. Preoperative mechanical axis deviation, medial proximal tibial angle, lateral distal tibial angle, and body mass index did not differ significantly between those with recurrence and those with without. Mean age at surgery was significantly different for those who developed recurrence compared with those who did not. Patients without recurrence were 4.3 years of age (range, 2.4 to 10.3 y) compared with 6.2 years of age (range, 2.9 to 10.1 y) for those who recurred (P<0.01). Of patients who developed recurrent deformity, there were significantly more patients with type C changes (71.7%, P<0.01) then either type A (22.5%) or type B (20.7%). High rates of recurrence were seen for both Langenskiold stage III (50%) and stage IV (69.6%).

CONCLUSIONS

Consistent with prior studies, age 5 seems to be a critical transition in the risk for recurrent deformity after tibial osteotomy. Extreme vertical sloping of the medial metaphyseal defect, as in some classic Langenskiold III lesions and more precisely described by type C in a newer, modified classification, carries a poor prognosis for successful correction by high tibial osteotomy alone or in combination with epiphysiolysis.

LEVEL OF EVIDENCE

Level II.

Eight-plate epiphysiodesis

Aims

Guided growth using eight-plates is commonly used for correction of angular limb deformities in growing children. The principle is of tethering at the physeal periphery while enabling growth in the rest of the physis. The method is also applied for epiphysiodesis to correct limb-length discrepancy (LLD). Concerns have been raised regarding the potential of this method to create an epiphyseal deformity. However, this has not been investigated. The purpose of this study was to detect and quantify the occurrence of deformities in the proximal tibial epiphysis following treatment with eight-plates.

Patients and Methods

A retrospective study was performed including 42 children at a mean age of 10.8 years (3.7 to 15.7) undergoing eight-plate insertion in the proximal tibia for correction of coronal plane deformities or LLD between 2007 and 2015. A total of 64 plates were inserted; 48 plates (34 patients) were inserted to correct angular deformities and 16 plates (8 patients) for LLD. Medical records, Picture Archive and Communication System images, and conventional radiographs were reviewed. Measurements included interscrew angle, lateral and medial plateau slope angles measured between the plateau surface and the line between the ends of the physis, and tibial plateau roof angle defined as 180° minus the sum of both plateau angles. Measurements were compared between radiographs performed adjacent to surgery and those at latest follow-up, and between operated and non-operated plateaus. Statistical analysis was performed using BMDP Statistical Software.

Results

Slope angle increased in 31 (49.2%) of operated epiphyses by a mean of 5° (1° to 23°) compared with 29 (31.9%) in non-operated epiphyses (p = 0.043). Roof angle decreased in 29 (46.0%) of operated tibias and in 25 (27.5%) of non-operated ones by a mean of 5° (1° to 18°) (p = 0.028). Slope angle change frequency was similar in patients with LLD, varus and valgus correction (p = 0.37) but roof angle changes were slightly more frequent in LLD (p = 0.059) and correlated with the change in inter screw angles (r = 0.74, p = 0.001).

Conclusion

The use of eight-plates in the proximal tibia for deformity correction and limb-length equalization causes a change in the bony morphology of the tibial plateau in a significant number of patients and the effect is more pronounced in the correction of LLD. Cite this article: Bone Joint J 2018;100-B:1112–16.

Association between leg bowing and serum alkaline phosphatase level regardless of the presence of a radiographic growth plate abnormality in pediatric patients with genu varum

When children around 2 years of age show leg bowing and diseases are ruled out based on radiographic findings without conducting blood tests, they are classified as "physiologic" genu varum. Since whether or not physiologic genu varum is associated with bone metabolism is unclear, this study was conducted to clarify the association between genu varum and bone metabolism in children. Thirty-five pediatric patients with genu varm who visited our out-patient clinic were enrolled. While two of the 35 children had nutritional rickets, showing abnormalities on both blood test (ALP, ≥1000 IU/L; iPTH, >65 pg/mL and 25(OH)D, ≤20 ng/mL) and radiographs (such as cupping, fraying or splaying), five of 35 children showed abnormalities on blood tests but not radiographs. While metaphyseal-diaphyseal angle (MDA) correlated with serum 25-hydroxy vitamin D (r = -0.35, p = 0.04) and magnesium (r = -0.36, p = 0.04), MDA and femorotibial angle (FTA) correlated with alkaline phosphatase (r = 0.43, p = 0.01 and r = 0.51, p = 0.006, respectively). A ridge regression analysis adjusted for age and body mass index indicated that ALP was associated with MDA and FTA. A logistic regression analysis adjusted for age and BMI indicated that higher ALP influenced an MDA >11°, which indicates the risk for the progression of genu varum (odds ratio 1.002, 95% confidence interval 1.0003-1.003, p = 0.021). The higher ALP (+100 IU), the higher risk of an MDA >11° (odds ratio 1.22). In conclusion, genu varum is associated with the alkaline phosphatase level regardless of the presence of radiographic abnormalities in the growth plate in children.

Guided growth for tibia vara (Blount's disease)

Blount's disease is commonly attributed to an intrinsic, idiopathic defect in the posteromedial proximal tibial physis resulting in progressive bowing of the leg, intoeing, and lateral knee thrust. Treatment has historically included bracing, physeal stapling, or corrective osteotomy, and was determined primarily by age at presentation. As we feel the pathology is not necessarily age dependent, we have elected to use the technique of guided growth using a lateral tension band plate to correct limb alignment as a first-line treatment in all patients presenting to our clinic as long as they had growth remaining and no evidence of a physeal bar.We identified 17 patients with tibia vara (27 limbs) who were managed by means of guided growth of the proximal tibia, from age 1.8 years to 15.1 years. Clinical and radiographic parameters were followed pre- and postoperatively. The response to guided growth was documented as were any related complications.Twenty-one (78%) limbs had complete normalization of their mechanical axis (middle 50% of knee). Time to correction averaged 13.5 months (8-19 months). There were no peri-operative complications. We observed hardware failure in 3 patients; 2 with screw breakage and 1 patient with hardware migration, none requiring subsequent osteotomy or further treatment. Two patients had rebound varus: one is being observed and another has undergone a repeat procedure.Patients with pathologic tibia vara present at various ages and have historically undergone various treatments ranging from bracing to tibial osteotomy based on age at presentation. We have found that guided growth utilizing tethering plates can be used effectively as first-line treatment in all patients with growth remaining. This minimally invasive method is predictable and well tolerated. Recurrent deformity, though unlikely, is easily remedied by repeating the process and does not preclude osteotomy if eventually needed. Concomitant resolution of ligamentous laxity and inward torsion can be anticipated as the mechanical axis is restored to neutral. The only contraindications for guided growth include an unresectable physeal bar or skeletal maturity.

Total Knee Arthroplasty in Patients with Blount Disease or Blount-Like Deformity

Blount disease is associated with complex deformity of the proximal tibia, and some patients will develop knee osteoarthritis. Five patients (eight knees) with Blount disease or Blount-like deformity underwent total knee arthroplasty. Mean proximal tibial metaphyseal-diaphyseal angle was 20.75°. Each patient had substantial posteromedial tibial bony defects and six knees required extensive medial releases. Two knees required increased constraint at index procedure. One patient has undergone bilateral revision surgery with rotating hinge prostheses. Mean WOMAC scores were 13.5 and Knee Society scores were 212.5 at average 75.2 month follow-up. Despite technical challenges, patients with these deformities can have successful outcomes after total knee arthroplasty. Surgeons should be prepared to address posteromedial tibial bony defects and consider constrained arthroplasty at the index procedure.

Significant Incidence of Extra-Articular Tibia Vara Affects Radiological Outcome of Total Knee Arthroplasty

Purpose

To identify and quantify the presence of extra-articular tibia vara that might influence the mechanical axis alignment after total knee arthroplasty (TKA).

Materials and Methods

A total of 48 TKAs in 30 osteoarthritic Indian patients were prospectively evaluated. The hip-knee-ankle angle (HKA), joint line convergence angle, and varus angulation at the femur and tibia were measured from the preoperative and postoperative standing hip-to-ankle radiographs. Four different methods were used to measure the varus angulation at the tibia: metaphyseo-diaphyseal angle (MDA), the angle between the anatomical axis and mechanical axis of the tibia, the angle between the proximal third and distal third of tibia and the angle between the proximal half and distal half of tibia.

Results

Extra-articular tibia vara quantified using MDA had the most positive correlation with HKA. Receiver operating characteristic plotting showed that MDA of >4° predicts abnormal postoperative HKA. Twenty-eight out of 48 knees had MDA of >4°, and 78.6% of these had postoperative HKA under-correction and 21.4% had less than ideal tibial component position.

Conclusions

A significant inherent extra-articular varus angulation best measured using MDA exists in the proximal tibia in osteoarthritic Indian patients undergoing TKA. MDA of >4° is associated with abnormal postoperative HKA. Computer navigation may be useful for achieving ideal correction in such cases.

Tibial bowing in children - what is normal? A radiographic study

PURPOSE

To define osseous landmarks on tibia radiographs in order to establish age-related normal values characterizing physiological tibial bowing in children.

MATERIALS AND METHODS

Five hundred and twenty-six patients aged 0-17 years with normal radiographs of the lower legs were identified and retrospectively reviewed by two blinded radiologists. In anteroposterior (ap)/lateral (lat)-views, 3 lines defined tibial length and angulation. Line-A connecting proximal to distal corner of tibial metaphysic, lines B and C corresponding to corners of tibial metaphysis. Angle A/B defines proximal, A/C distal tibial-angulation. Tibial curvature is defined by distance of line-D parallel to A and tangential to tibial cortex. Normal values were calculated with linear-regression. Intra-/Interreader agreement were tested with a Bland-Altman-plot.

RESULTS

Intrareader-agreement: Reader 1 showed a bias of -0.1, standard-deviation of bias was 1.9 and 95 %-limits-of-agreement -3.9- 3.7. Reader 2: -0.01, 2.4 and -4.7- 4.7. Interreader: 0.2, 1.6 and -2.9- 3.3. Angle-A/B ap was 80-100°, increasing with age (86.5-88); angle-AC ap was 82-107°(96.8-90.5), angle-AB lat was 81-107°(93.0-98.0); angle-AC lat was 76-102 (89.5-86.5); depth of curve ap was 0-11 % (8-3.5) and lat 2-13 %, (8.5-3.5).

CONCLUSION

Age dependent tibial bowing can be assessed with this new measurement system and age-related normal-values characterizing physiological tibial bowing in children is established.

KEY POINTS

• Tibial Bowing is diagnosed on conventional radiographs. • Existing Methods provide limited level of confidence. • New methods provide easy to assess landmarks in all patient ages. • Existing methods require higher radiation dose compared to new method presented.

Orthosis Effects on the Gait of a Child with Infantile Tibia Vara

Infantile tibia vara (ITV) is an acquired form of tibial deformity associated with tibial varus and internal torsion. As there is currently insufficient data available on the effects of orthotics on gait parameters, this study aimed to document the influence of orthosis on walking. A male infant with bilateral tibia vara used orthoses for five months. Gait evaluations were performed pre- and posttreatment for both legs. The kinematic parameters were collected by using a motion analysis system. The orthotic design principle was used to correct the femur and tibia. Posttreatment gait parameters were improved compared to pretreatment parameters. After 5 months, there was remarkable change in the stance-phase degrees of frontal plane hip joint abduction and knee joint varus. We found that orthoses were an effective treatment for the infantile tibia vara gait characteristics in this patient. Full-time use of single, upright knee-ankle-foot orthosis with a drop lock knee joint and application of corrective forces at five points along the full length of the limb were effective.

The coronal alignment after medial unicompartmental knee arthroplasty can be predicted: usefulness of full-length valgus stress radiography for evaluating correctability

PURPOSE

We aimed to clarify whether the coronal alignment after medial unicompartmental knee arthroplasty (UKA) is predictable using preoperative full-length valgus stress radiography.

METHODS

Thirty-seven consecutive patients with a mean age of 71.5 ± 7.0 years awaiting medial UKA were recruited. Full-length weight-bearing radiographs of the lower limbs were obtained pre- and postoperatively. Preoperative full-length valgus stress radiography in the supine position was also performed, and the transition of the hip-knee-ankle angle (HKAA) and the weight-bearing ratio were assessed. The tibia first cut technique was used, and the distal femur was cut parallel to the cutting surface of the proximal tibia during surgery.

RESULTS

The mean postoperative HKAA was 2.0° ± 2.1° varus, and the mean weight-bearing ratio was 43.1 ± 7.7 %; each of these parameters demonstrated significantly strong correlations with the values on the preoperative valgus stress radiographs (p < 0.01), while the correlation between the postoperative alignment and the preoperative standing alignment without stress was moderate (p < 0.01). The postoperative alignment was slightly undercorrected compared to that observed on the valgus stress radiographs (p < 0.05), and no knees exhibited evident overcorrection compared to that on the valgus stress radiographs.

CONCLUSION

Preoperative valgus stress radiography is useful for evaluating the correctability of varus deformities and predicting the postoperative coronal alignment. For clinical relevance, performing preoperative valgus stress radiography would help to more precisely select patients and, when combined with the tibia first cut technique, aid in achieving the expected knee alignment and avoid severe undercorrection or overcorrection.

LEVEL OF EVIDENCE

Diagnostic study, Level II.

Obesity is associated with greater valgus knee alignment in pubertal children, and higher body mass index is associated with greater variability in knee alignment in girls

OBJECTIVE

In adults, osteoarthritis (OA) is associated with obesity and knee alignment. Whether knee alignment differences develop during childhood and are associated with obesity is unknown. We assessed the distribution of knee alignment in children and adolescents, and determined how knee alignment differs between obese and nonobese children.

METHODS

This cross-sectional study examined knee alignment in 155 healthy weight and 165 obese subjects. Knee alignment [metaphyseal-diaphyseal angle (MDA) and anterior tibiofemoral angle (ATFA)] and fat mass were measured using whole body dual-energy X-ray absorptiometry (DEXA). National reference data were used to generate age- and sex-specific body mass index (BMI, kg/m(2)) Z-scores. Multivariable linear regression was used to identify independent factors associated with ATFA and MDA.

RESULTS

The mean MDA and ATFA were similar between obese and nonobese subjects. In stratified analyses, females had greater variability in MDA and ATFA values (p < 0.001 and p = 0.04, respectively) at higher BMI Z-scores. Compared with healthy weight controls, obese subjects had less valgus of the MDA prior to the onset of puberty (+ 2.0°, p = 0.001), but had greater valgus at later pubertal stages (-1.9°, p = 0.01).

CONCLUSION

We found significantly greater variability in knee alignment among females at higher BMI Z-scores, and greater valgus alignment in obese adolescents in late puberty. The major limitation is the use of DEXA for assessment of alignment, which needs validation against longstanding radiographs. Longitudinal studies are needed to determine whether childhood obesity is a risk factor for progressive malalignment that may predispose to pain and risk of early osteoarthritis.

Do we need to do overcorrection in Blount's disease?

PURPOSE

In order to prevent recurrent deformity, overcorrection in Blount's disease has been a common practice by most paediatric orthopaedic surgeons. However, some patients have persistent valgus alignment resulting in awkward deformity. The femoro-tibial angle (FTA) was measured in this series of cases to determine the necessity of such practice.

METHOD

During 1998-2010, patients with Blount's disease stage 2 by Langenskiold, aged from 30 to 40 months who had failed from bracing and underwent valgus osteotomy were included. Seventeen legs had postoperative FTA 7-13° (group 1) and 48 legs had postoperative FTA more than 13° (group 2). ROC curve was used to determine the appropriate FTA that was suitable to prevent recurrence.

RESULTS

Four legs had recurrence (28.6%) in group 1 and six legs (12.5%) had recurrence in group 2. Chi-square test between two groups were not statistically significant in recurrence (p = 0.434). Age and BMI were not statistically significant between recurrent and non-recurrent groups. The ROC curve shows that overcorrection more than 15° did not show benefit to prevent the recurrence in Blount's stage 2.

CONCLUSION

Our study showed that the overcorrection group had non-statistically significant recurrence compared to the non-overcorrection group, and overcorrection more than valgus 15° has no benefit to prevent recurrence.

Multicenter study of Blount disease in Japan by the Japanese Pediatric Orthopaedic Association

BACKGROUND

In order to investigate the epidemiology and features of Blount disease in Japan, the Japanese Pediatric Orthopaedic Association conducted a multicenter study on Blount disease in 2003.

METHODS

Questionnaires were sent to 1,350 training hospitals of the Japanese Orthopaedic Association. This study included those with stage I or II diagnosed between 1990 and 2002 and those with stage III or higher diagnosed between 1980 and 2002 based on the Langenskiöld classification. The questionnaire items included age at diagnosis, sex, presence or absence of a family history of bowlegs, past history of trauma, birthplace, age when starting to walk, height and weight at the initial presentation, laterality of the affected knee, disease types (infantile or adolescent), treatments, and plain radiographic findings.

RESULTS

The results for 212 patients with 296 affected knees were obtained. The disease types were infantile in 190 patients with 270 affected knees and adolescent in 22 patients with 26 affected knees. There were more girls among cases with both types. Among the infantile-type cases, there were more patients with bilaterally affected knees; however, in the adolescent-type cases, there were more patients with unilaterally affected knees. Patients with either type tended to be obese at diagnosis. There was little difference in age at which patients with either type started to walk, compared with the mean age for the general population. Conservative treatment was applied to most infantile-type cases in stage I or II, whereas surgery was performed in all but one of those with stage III or IV of the disease. Most adolescent-type cases underwent surgery.

CONCLUSIONS

This was the first multicenter study on Blount disease in Japan. Among 296 knees, the majority of these knees had stage I or II Blount disease. Very few cases had stage III or higher disease, and there were 35 knees with the infantile type and 19 with the adolescent type in the 23 years from 1980 through 2002.

Orthotic variations in the management of infantile tibia vara and the results of treatment

BACKGROUND

Infantile tibia vara is an acquired form of tibial deformity associated with tibial varus and internal torsion. Several methods have been described for orthotics treatment. The purpose of this study was to determine the effectiveness of orthotics treatment in infantile tibia vara.

STUDY DESIGN

Controlled trial.

OBJECTIVE

The aim of this study was to compare the effect of different types of orthoses and correction methods on decreasing the curve in children with severe genu varum.

METHODS

Three different types of knee-ankle-foot orthoses were applied to 35 lower extremities of 22 pediatric participants who were 19-38 months of age. The same orthotic design principles were used to correct the femur, while different designs were applied to correct the tibia. The orthoses used on 20 participants were evaluated for differences among them and their effects on the treatment process. In addition, methods used in the treatment, problems encountered, production of different types of orthoses, convenience of application of the orthoses, and degree of patients satisfaction are discussed in this article.

RESULTS

The mean duration of treatment of the participants until completion of treatment was 25.3 ± 9.7 weeks with a minimum of 9 weeks and a maximum of 41 weeks. No statistically significant correlation was found between the duration of orthotic use in patients with a successful outcome and percentile height and percentile weight. When the duration of treatment using the different types of orthoses was analyzed, significant differences were found between Type 1 and Type 2, and Type 1 and Type 3 orthoses (p < 0.05), while no difference was observed between Type 2 and Type 3 orthoses (p > 0.05).

CONCLUSION

We found that bracing is an effective form of treatment for infantile tibia vara up to 38 months of age. We conclude that full-time use of knee-ankle-foot orthoses exerting corrective forces from five points along the full length of the limb was effective.

Reliability of lower-limb alignment measurements in patients with multiple epiphyseal dysplasia

BACKGROUND

Although radiographic measurements are used in multiple epiphyseal dysplasia (MED) during correction of lower-limb alignment, the reliabilities of the measurements are unclear.

QUESTIONS/PURPOSES

We determined interobserver and intraobserver reliabilities of the measurement methods used in evaluation of lower-limb alignment in MED.

METHODS

After consensus building, we included 10 radiographic measurement methods widely used to evaluate lower-limb alignment: mechanical tibiofemoral angle, anatomic tibiofemoral angle, mechanical axis deviation, joint line convergence angle, mechanical lateral distal femoral angle, anatomic lateral distal femoral angle, mechanical medial proximal tibial angle, anatomic medial proximal tibial angle, epimetaphyseal angle, and tibial metadiaphyseal angle. A study group consisting of 30 patients with MED was compared with a control group consisting of 30 sex- and age-matched patients with genu varum and genu valgum. Mean age in both groups was 11 years (study group: SD, 2 years; range, 6-16 years; control group: SD, 2 years; range, 6-15 years). Interobserver and intraobserver reliabilities of all radiographic measurement methods were obtained and expressed by intraclass correlation coefficients (ICCs).

RESULTS

Mechanical tibiofemoral angle, anatomic tibiofemoral angle, and mechanical axis deviation were associated with high interobserver reliability (ICCs, 0.987, 0.985 and 0.982, respectively). Epimetaphyseal angle had the lowest reliability (ICC, 0.280). Intraobserver reliability exhibited similar trends, with mechanical axis deviation and mechanical tibiofemoral angle having the highest ICCs and epimetaphyseal angle the lowest.

CONCLUSIONS

Mechanical tibiofemoral angle, anatomic tibiofemoral angle, and mechanical axis deviation are reasonably reliable measures of alignment in MED. The lateral distal femoral angle and medial proximal tibial angle (mechanical and anatomic) can be used as complementary measurement methods.

LEVEL OF EVIDENCE

Level II, diagnostic study. See Instructions for Authors for a complete description of levels of evidence.

Treatment of infantile Blount disease with lateral tension band plating

BACKGROUND

Growth manipulation has had increasing popularity in the treatment of lower extremity angular deformities in children. This paper discusses the use of growth manipulation for the treatment of infantile Blount disease as an alternative to proximal tibial osteotomy.

METHODS

A retrospective chart and radiographic review was carried out for 12 children (18 limbs) who had treatment of infantile Blount disease with application of lateral proximal tibial tension band plates. Some children also had distal femoral lateral plates applied. Serial radiographs were measured to show response to growth manipulation.

RESULTS

The success rate of growth manipulation in this group was 89%. Failures and delayed correction were attributed to wound infection that required plate removal and broken screws. Some recurrence of varus has occurred in a few patients.

CONCLUSIONS

Growth manipulation is an effective means of treating infantile Blount disease in appropriate patients. Patients must be monitored for screw breakage after surgery. After removal of the plates, the risk of recurrent varus is attributed to the poor growth potential of the proximal medial tibial physis.

LEVEL OF EVIDENCE

Therapeutic study, Level IV.

Lower limb deformity following proximal tibia physeal injury: long-term follow-up

BACKGROUND

Proximal tibial physeal injuries are quite rare, but their complications can be of great importance. The purpose of this study was to evaluate the effect of this injury on the axis and length of a child's limb.

MATERIALS AND METHODS

This study focused on 12 patients with proximal physeal injury of the tibia (8 boys and 4 girls; mean age at the time of injury: 8.9 years). Injuries were classified according to the Salter-Harris scheme into 5 types (type II--7 patients, type III--3 patients, type IV--1 patient, type V--1 patient). In 5 cases, a coexisting fracture of the injured limb was observed (fibular fracture--3 cases, intercondylar fracture--1 case, tibial tubercle fracture--1 case). Ten patients were treated conservatively and 2 patients underwent an operation. Seven of the 12 patients were available for long-term follow-up, with a mean duration of 14.4 years (11.2-22.0 years).

RESULTS

Angular deformity was observed in 6 of the 7 patients, with a mean valgus deformity of 2.7°, within an average of 5.8 months after the injury. After 3 years of follow-up, complete remodeling was observed in all of those 6 cases (4 of the patients were treated conservatively and 2 underwent surgery). One patient developed 6 mm of tibial shortening. No functional limitation or pain was recorded in any of the patients during the follow-up.

CONCLUSIONS

Injury to the proximal tibial epiphysis, while rare, may result in angular or length disturbance, regardless of the initial treatment (conservative or surgical). Parents should always be informed of this possibility, and long follow-up is indicated. Nevertheless, this type of injury rarely results in functional limitations.

Orthopaedic manifestations in a case of Lenz microphthalmia syndrome

BACKGROUND

Lenz microphthalmia syndrome is an X-linked recessive disorder characterized by microphthalmia and dental, urogenital, and skeletal anomalies. This case report represents the first detailed account of congenital kyphoscoliosis in the Lenz microphthalmia literature.

METHODS

We present a case of Lenz microphthalmia syndrome with progressive kyphosis, spinal stenosis, and late-onset tibia vara along with many of the typical features of the disorder. In addition, we provide insight into the syndrome by reviewing the existing Lenz microphthalmia literature.

RESULTS

Congenital kyphoscoliosis that is prone to reoccurrence after posterior spinal fusion is an unusual entity that may be associated with Lenz microphthalmia.

CONCLUSIONS

We recommend close monitoring and early surgical intervention with posterior spinal fusion for congenital kyphosis in patients diagnosed with Lenz microphthalmia syndrome. However, more data on similar patients are necessary to define the optimal treatment strategy. LEVEL OF EVIDENCE (FOR CLINICAL ARTICLES): Level V.

Use of the eight-Plate for angular correction of knee deformities due to idiopathic and pathologic physis: initiating treatment according to etiology

PURPOSE

Angular deformities of the knee resulting from idiopathic, congenital, or acquired causes are commonly encountered in pediatric orthopedics. Whereas physiological deformities should be treated expectantly, the remaining often progress enough to warrant operative treatment, despite attempted bracing. Historical methods of surgical treatment (e.g., epiphysiodesis and stapling) have yielded to the increasingly popular method of reversible guided growth using the eight-Plate.

METHODS

We studied 58 patients with knee angular deformities managed with eight-Plate guided growth. All etiologies except physiological deformities and those with very slow growth rate were included. Each patient was under appropriate medical management during the entire duration of treatment and after plate removal.

RESULTS

In the dysplasia/syndrome group, we noted complete correction in 22 patients (78.5%), partial correction in 5 (17.9%), and no correction in 1 patient (3.6%). All cases of idiopathic deformities resolved. Patients with osteochondral dysplasias and genetic syndromes underwent earlier intervention and slower correction than those with idiopathic genu varum or valgum. The time difference in reaching a neutral mechanical axis between the two groups (11 months in idiopathic versus 18 months in pathological physis) could be explained by a significant difference in growth speeds (P = 0.003).

CONCLUSION

Results indicate that early intervention is advisable for patients with osteochondral dysplasias/syndromes as subsequent correction takes longer. If rebound growth causing recurrent deformity occurs, guided growth can be safely repeated. Additionally, complications reported with other techniques such as hardware failure, physeal violation by the implant, premature physeal closure, and overcorrection were not reported while using the eight-Plate.

Fixator-assisted medial tibial plateau elevation to treat severe Blount's disease: outcomes at maturity

INTRODUCTION

Severe forms of Blount's disease may be associated with medial tibial plateau (MTP) depression. Management should then take account of joint congruence, laxity, limb axis, torsional abnomality, leg length discrepancy (LLD) and eventual recurrence history.

PATIENTS AND METHODS

Eight knees (six patients) were managed in a single step comprising MTP elevation osteotomy, lateral epiphysiodesis and proximal tibia osteotomy to correct varus and rotational deformity. Fixation was achieved using an Ilizarov external fixator. Mean age was 10.5 years. Mean hip-knee-ankle (HKA) angle was 151°; distal femoral varus, 94°; metaphyseal-diaphyseal angle (MDA), 27°; and angle of depression of the medial tibial plateau (ADMTP), 42°. Predicted residual proximal tibial growth was 2.6 cm.

RESULTS

At a mean 48 months' follow-up, results were good in six cases, medium in one and poor (due to incomplete lateral epiphysiodesis) in one. Mean lateral tibial torsion was 9° and final LLD 11 mm. Weight-bearing was resumed at 2 months, and the fixator was removed at 5.5 months postoperatively. At end of follow-up, mean HKA angle was 179.6°, MDA 7.3° and ADMTP 5.4°.

DISCUSSION

This technically demanding procedure gave satisfactory results in terms of axes and congruence; longer term assessment remains needed.

LEVEL OF EVIDENCE

Level IV. Retrospective study.

Normal development of the knee angle in healthy Indian children: a clinical study of 215 children

PURPOSE

Physicians should be aware of the physiological variations of the knee angle in the local population to avoid unnecessary intervention in normal children. The normal development of the knee angle in children has been studied in various ethnic groups. However, there is a scarcity of such literature for Indian children.

METHODS

Using clinical methods, the tibiofemoral angles (TFAs) were measured in 215 healthy Indian children ranging from 2 to 15 years of age. A record of the intermalleolar distance (IMD) and intercondylar distance (ICD) was also kept of all of the subjects.

RESULTS

We found that physiological varus rarely persists beyond 2 years of age in Indian children. A progressive increase in knee valgus occurs after 2 years of age, with peak knee valgus averaging almost 8° at around 6 years of age. Thereafter, the valgus at the knee decreases and, after the age of 10 years, stabilizes to around 4-5° in most of the children. Indian girls show, overall, more valgus alignment of the knees as compared to boys.

CONCLUSIONS

The overall pattern of development might be slightly different in Indian children, especially in Indian girls, with early reversal of physiological varus (<2 years of age) and a late peak of maximal valgus at the knee (6 years of age). Varus after 3 years seems atypical for Indian children. We provide an elaborate set of data for the mean TFA of different age groups and believe that this data could be of potential benefit to the physicians while evaluating lower limb alignment in Indian children aged 2-15 years.

Can Blount's disease heal spontaneously?

INTRODUCTION

In stage 1 of all currently accepted classifications for infantile tibia vara, the diagnosis is difficult between physiological bowing and true Blount's disease. There is no evidence of prognosis criteria for surgical treatment at this stage.

PATIENT AND METHODS

We retrospectively studied a series of 26 patients born in the Indian Ocean area, presenting at stage 1 of the disease, in order to determine whether any of them were likely to heal without treatment.

RESULTS

It was found that children seen at stage 1 of infantile tibia vara have a one-in-three chance of healing spontaneously.

DISCUSSION

An alternative classification in three stages could then provide more suitable therapeutic indications: stage 0: possible Blount's disease (patient older than 2.5 years); stage 1: certain Blount's disease, active physis (+) (progressive varus, age >3 years, typical image with no epiphysiodesis bridging); stage 2: certain Blount's disease, inactive physis (-) (superomedial tibial bony bridge).

LEVEL OF EVIDENCE

Level IV. Retrospective study.

Outcome analysis of surgery for Blount disease

BACKGROUND

The purpose of this study was to evaluate the results of surgery for Blount disease using a patient-derived outcome assessment. Our hypothesis was that an outcome score that quantitates the patient's level of satisfaction should correlate with specific ranges of correction for those radiologic variables traditionally used to evaluate Blount disease. The surgeon's aim should be to realign abnormal preoperative geometry to achieve those ranges that have a significant correlation with good outcome.

METHODS

Medical records from 2 hospitals (Barbados and Trinidad) were reviewed and patients who had surgery for Blount's from 1997 to 2005 were identified and recalled. Responders completed a Blount's Outcome Questionnaire, were examined clinically, and standing radiographs were taken. The questionnaire was designed by modifying the AAOS Pediatrics-Parent/Child Outcome Instrument. Linear regression was used to assess the predictive effect of selected radiographic measures on a visual analog pain score and satisfaction score calculated from the questionnaire. The model was adjusted for confounders: country, age at the time of study, sex, body mass index, and years postsurgery. Variables in the adjusted model achieving significance at P<0.05 were included in a multiple regression analysis.

RESULTS

Fifty knees in 41 patients were included. The median satisfaction score was 93%. The metaphyseal-diaphyseal angle (MDA) and anatomical femoral-tibial angle (aFTA), both had a quadratic effect on the pain score (P<0.001). The predicted pain score was minimized at the MDA range of 0 to -10 degrees and at the aFTA range of 0 to +5 degrees. A significant effect on the satisfaction score was noted for MDA (P=0.02) and aFTA (P<0.001) with scores maximized at the MDA range of +5 to -5 degrees and at positive aFTA (valgus angulation). For women the satisfaction scores were lower and the pain scores higher. Overweight patients had higher pain scores.

CONCLUSIONS

Results of this evaluation of the association between patient outcome scores (for pain and satisfaction) and postoperative clinical and radiologic variables support the recommendation that surgical correction should aim at producing an MDA score between -5 and +5 degrees and a valgus alignment with an aFTA score of 0 to 5 degrees.

LEVEL OF EVIDENCE

Therapeutic study, investigating the results of treatment. Level III.

Advances in growth plate modulation for lower extremity malalignment (knock knees and bow legs)

PURPOSE OF REVIEW

Lower extremity angular deformities are among the most common nontraumatic conditions in children being referred to pediatric orthopedists. Understanding of this abnormality is essential for pediatricians and primary caregivers. There is a development in the surgical management of these problems that has improved the quality of care of affected children and adolescents.

RECENT FINDINGS

In recent years, we have improved our understanding of consequences of lower limb angular deformities on knees. New treatment options for angular deformity include the method of 'guided growth' using small, extraphyseal tension band plates.

SUMMARY

The development of this surgical technique for growth plate manipulation for the treatment of angular deformities of knees has expanded the indications for surgical management and has a potential to decrease the incidence and the severity of complications.