Background

Varus axial deformity of lower limbs occurs more frequently in soccer players than in general population. Varus deformity alters lower limb biomechanics, which results in medial joint space overloading, overuse problems and consequently in an early onset of degenerative joint disease. It has been shown that, i.e. between 13 and 15 years of age, probably due to a specific loading pattern in soccer training.

Purpose

The purpose of the study was to identify any subtle changes in growth plates around knee joints of adolescent players using an advanced quantitative MR method – diffusion weighted imaging (DWI).

Methods

Eleven 14-year-old male soccer players were included in the study, theirs knees and adjacent growth plates were evaluated during the 2-months interval (intensive football training following 1 month of summer football vacation) using MR. MR evaluation was conducted in coronal plane by PD-FSE and DWI. All images were screened for any major pathological changes in and around the knees. Later on, growth plate surface area (GPSA), and ADC (apparent diffusion coefficient) values were measured in two most central coronal slices within four selected regions: distal femur medial (DFM), distal femur lateral (DFL), proximal tibia medial (PTM), proximal tibia lateral (PTL).

Results

No major pathology was observed on MRs of the participants knees. After the two months interval GPSA was minimally, not statistically significant reduced in all four parts of interest: DFM 278 vs. 272, DFL 265 vs. 261, PTM 193 vs. 192, and PTL 214 vs. 210 (mm2). ADC decrease was statistically significant only for PTM: DFM 1.27 vs. 1.22, DFL 1.37 vs. 1.34, PTM 1.13 vs. 1.03 (p = 0.003), PTL 1.28 vs. 1.22(mm/s x 10-3).

Conclusions

This study confirms the usefulness of DWI in the evaluation of growth plates. The significant lower ADC values in PTM proven by quantitative DWI measurements indicate increased cellularity in the medial part of the proximal tibial growth plate around the knee in asymptomatic adolescent players. It is consistent with the histological findings in animal studies where their physis were exposed to the compressive forces. This asymmetric knee growth plate’s disturbance may indicate a reason for increased incidence of varus knees between soccer players.