Radiographic analysis of lower limb alignment in professional football players

Youth soccer players: patterns of injury involving the primary growth plates of epiphyses

Youth soccer (football) is immensely popular internationally. Earlier participation, sport sub-specialization, and year-around practice have led to an increased incidence of injury from both acute trauma and repetitive overuse. The growth plates (physes) of the immature skeleton are particularly vulnerable to injury and delayed diagnosis can lead to future growth disturbance and long-term morbidity. Familiarity with the various components of the growth plate complex necessary for ensuring normal endochondral ossification is fundamental in understanding the various patterns of imaging findings following injury. This review discusses the zonal columnar arrangement of the growth plate proper and the contrasting function of the vasculature within the subjacent epiphysis and metaphysis. This is followed by an evidence-based discussion of the common patterns of injury involving the epiphyseal primary growth plate observed among youth soccer players: subcategorized into physeal fractures (direct injury) and physeal stress injuries (indirect insult to subjacent metaphysis). In this section, the role of imaging and characteristic imaging features will be discussed. While the normal physiologic and pathophysiologic mechanisms can be applied to other growth plates, such as primary growth plates underlying the apophyses and secondary growth plates surrounding the secondary ossificiation centers, which also undergo endochondral ossification, the current review is focused on injuries involving the primary growth plates underlying epiphyses.

The influence of the lower limb components on genu varum in football players: a full leg length magnetic resonance imaging study

BACKGROUND

This study aimed to evaluate lower extremity alignment in football players with and without genu varum using magnetic resonance imaging (MRI) and to investigate the underlying mechanisms and contributing factors to malalignment.

METHODS

This prospective case-control study included 36 male football players aged 16-19 years, divided into two groups: 18 with genu varum and 18 controls with normal lower extremity alignment. Full-length lower extremity MRI was used to assess alignment parameters. The isokinetic strength of the concentric knee extensor-flexor and concentric hip abductor-adductor muscles was measured using an isokinetic dynamometer at angular velocities of 60°/sec and 180°/sec. Logistic regression was used to evaluate the risk factors for genu varum.

RESULTS

Genu varum group had a mean mechanical axis deviation (MAD) of 14 ± 5 mm (p < 0.001), with 11 players exceeding the clinical cutoff of 15 mm. Significant differences were observed in the lateral distal tibial angle (LDTA) (p = 0.014), lateral proximal femoral angle (LPFA) (p = 0.017), and medial distal femoral angle (mLDFA) (p = 0.002) between the groups. Muscle strength values were comparable between the groups, except for the hip adductor-abductor strength ratio at 60°/sec, which was significantly lower in the genu varum group (p = 0.008), while all other comparisons were non-significant (p > 0.05). The regression analysis demonstrated that the mechanisms responsible for varus alignment in football players differ between the dominant and non-dominant leg.

CONCLUSIONS

The findings in this study suggest that the proximal tibial deformity is a key factor in malalignment among football players with genu varum. Differences in alignment were observed between dominant and non-dominant legs. Strength values were similar between players with and without varus alignment, except for the 60˚/sec angular velocity Add/Abd ratio.

CLINICAL TRIAL REGISTRATION

NCT06606964 / 16.09.2024.

LEVEL OF EVIDENCE

Level III.

Assessment of the Radiographic Angular Parameters in the Coronal Plane of the Lower Limbs in Subjects without Knee Osteoarthritis in a Reference Hospital of the Brazilian Unified Health System

Objective  The present study aims to demonstrate the radiological angular parameters of a sample of patients treated at our institution and to compare the radiological abnormalities with other classifications or parameters from the literature. Methods  We evaluated a sample of patients submitted to panoramic radiographic examinations of the lower limbs. The inclusion criteria were: (1) Patients without knee osteoarthritis as assessed by an orthopedist. (2) Bilateral radiographic evaluation in the panoramic examination of the lower limbs. (3) Panoramic radiographic examination of the lower limbs before any surgical procedure. (4) Patients over 18 years old. Results  We analyzed a total of 1,242 lower limbs. The axis was neutral in 875 lower limbs (70.4%). The main etiology was non-traumatic, with a varus deviation of the tibial segment in 253 cases and the deformity apex in the proximal third of the tibial segment. A valgus deviation of the mechanical axis was more common in non-traumatic etiologies (82.3%). Per the Coronal Plane Alignment of the Knee (CPAK) classification, type I was the most frequent (44.8%), followed by type III (37.1%). Conclusion  We identified changes in the angular parameters in patients from a reference hospital from the Brazilian Unified Health System which were different from population samples from other countries.

High Prevalence of Varus Knee Malalignment in Adolescent Football Players-Clinical Lower Leg Axis Measurements of Male Junior Football Players Aged 7 to 18 Years

BACKGROUND

Football, as the most popular sport worldwide, has long been under suspicion of causing varus knee alignment as early as adolescence. However, no causal relationship has yet been found. The first step to do so would be to determine the prevalence of lower leg malalignment among male junior football players depending on age, performance level and the number of active seasons played.

METHODS

Leg axis alignment in frontal plane was determined in male junior football players of different age levels between 7 and 18 years by measuring the intercondylar/intermalleolar distance (ICD/IMD) in an upright position. In addition to anthropometric data, multiple sport-specific data such as the start of their football career or training time per week were collected by means of questionnaires (clinical trial registration number: DRKS00020446).

RESULTS

207 male junior football players were included in this survey. The mean age was 12.8 years. Within the group of 15 to 18 year olds, the prevalence of varus knee malalignment was highest at just under a third (32.1%). In the subpopulation that played actively for more than ten seasons, 28.9% showed varus leg axis. Regarding performance level, the highest IMD/ICD values and highest prevalence of varus alignment were found among football players who play on a semi-professional level (16.7%), compared to amateur (11.4%) and high-performance levels (2.8%).

CONCLUSIONS

Further research is necessary to investigate if this high prevalence of varus knee in children of a higher age and higher playing levels is due to the selection bias of football players with varus knee or a real development of varus knee in individuals.

Towards a better understanding of knee angular deformities: discrepancies between clinical examination and 2D/3D assessments

INTRODUCTION

Discrepancy between the clinical examination and the 2D/3D radiographs is a common concern in patients with angular or rotational deformities of the lower limbs, as it may alter clinical judgment and subsequent treatment. The aim was to identify such discrepancies and assess determinants that may contribute to their existence.

MATERIALS AND METHODS

A retrospective chart review was conducted on 329 consecutive patients (658 lower limbs) who underwent physical examination and long-leg biplanar radiographs in our institution between 2013 and 2018 for limb length discrepancy or angular deformity of the knees (varus/valgus). Eleven parameters were measured on 2D and 3D images. 3D measurements were based on standing biplanar X-rays and their 3D reconstructions and were considered the gold standard. Contingency tables and multiple linear regression were used to assess discrepancies between the three modalities and their determinants respectively.

RESULTS

Significant mismatches were found between physical examination and 2D images (1% in varus and 1% in valgus), between physical examination and 3D assessment (1% in varus and 4.6% in valgus) as well as between 2 and 3D assessments (1.9% in varus and 7.6% in valgus). The significant determinants of the mismatch between 2 and 3D modalities were frontal pelvic obliquity, neck shaft angle, knee flexion, femoral torsion, and tibial mechanical angle.

CONCLUSION

In the presence of positional and/or morphological deformities, physical examination and 2D assessment of knee alignment could be biased due to axes projection errors. A better understanding of 3D alignment of the knee as part of the entire lower limb from pelvis to toes, may lead to a better diagnosis and subsequently a better treatment of knee angular deformities.

The Coronal Alignment of Lower Limbs in the Adolescent Football and Ice Hockey Players

Background

To investigate the influence of sport-specific activities on coronal axial alignment of the lower limbs in adolescent football and ice hockey players.

Methods

This cross-sectional study targeted healthy adolescent male football and ice hockey players with at least 3 years of sports participation. 90 football and 38 ice hockey players aged 12-16 years were divided into five age-matched subgroups. Coronal alignment of the lower limbs was determined by measuring the players' intercondylar or intermalleolar (ICD-IMD) distance with a custom-made calliper. In addition, their sports history was recorded. An age-matched comparison between the two sports groups was performed using the two-way model ANOVA and a multiple regression model for ICD-IMD was constructed. Results were additionally compared with age-matched data from the general population published in recent literature.

Results

A statistically significant increase in ICD-IMD values (p < 0.05) was found between 12 (football 0 mm; ice hockey - 64 mm) and 16 years (football 340 mm; ice hockey 310 mm) in both sports groups. Results of regression analysis of pooled group data showed that ICD-IMD has low positive correlation (r = 0.407; r2 = 0.168; p < 0.05) with time of participation in sport, but no association with age of athletes at the start of their sport participation (r = - 0.018; r2 = 0.000; p > 0.05). There were no statistically significant differences between the two groups at any time point. Both sports groups showed a significant increase in ICD-IMD values (mean 198 mm) after the age of 14 compared to the general population.

Conclusions

Participation in football and ice hockey is associated with a similar increase in ICD-IMD in the adolescent years in male athletes. The observed increase was higher in both groups of athletes than in their peers who do not regularly participate in sports.

Level of Evidence

Level 4 (case series).

Radiographic Measures for the Assessment of Frontal and Sagittal Knee Alignments and the Associated Normality Values: A Meta-Analysis

Objective

The purpose of this literature review was to identify knee alignment assessment methods using radiography in the sagittal and frontal planes and to identify normality values for classifying knee alignment using these methods.

Methods

A systematic review with a meta-analysis was conducted. The eligibility criterion was studies that performed radiographic examinations to assess the knee alignment of adults without a history of hip or knee prosthesis surgery. The methodological qualities of the included studies were assessed using the QUADAS-2 tool. A meta-analysis was performed to measure the normality values of knee alignment in the frontal plane.

Results

The hip-knee-ankle (HKA) angle was the measure most frequently used to assess knee alignment. Only a meta-analysis of HKA normality values was possible. Thereby, we found normality values of the HKA angle for the overall population, men, and women. The normality values of knee alignment for healthy adults that were found in this study were as follows: overall sample (male and female patients) HKA angle = -0.2° (-2.8° to 2.41°), male patient HKA angle = 0.77° (-2.91° to 7.94°), and female patient HKA angle = -0.67° (-5.32° to 3.98°).

Conclusion

This review identified the most common methods and expected values for knee alignment assessment methods using radiography in the sagittal and frontal planes. We suggest HKA angles ranging from -3° to 3° as the cutoff for classifying knee alignment in the frontal plane, in accordance with the normality limits found in the meta-analysis.