Table 1

Characteristics of included studies

AuthorParticipant
Demographics
PopulationTendonParameter investigatedTendon abnormality definition
Boesen et al46n=86 (56M/30F)
Mean age 21.7
Semiprofessional badminton playersAchilles and patellarVascularityAbnormal: Presence of increased vascularity (≥grade 1) according to a defined six-point scale (grade 0–5).
Comin et al10n=79 (35M/44F)
Mean age 27.4
Professional ballet dancersAchilles and patellarThickness
Hypoechogenicity
Vascularity
Tendon clefts
Intratendinous calcifications
Abnormal: Presence of (1) hypoechogenicity, or (2) increased thickness, or (3) vascularity, or (4) intratendinous calcifications (all undefined)
Cook et al36n=26 (8M/18F)
Age range 14–18
Elite junior basketball playersPatellarThickness
Hypoechogenicity
Abnormal: Presence of (1) thickness, or (2) hypoechogenicity (all undefined).
Cook et al37n=24 (24M)
Mean age 27.5
Athletes from various sports: basketball, cricket, netball and Australian rules football.PatellarThickness
Hypoechogenicity
Abnormal: Presence of (1) thickness, or (2) hypoechogenicity (all undefined).
Fredberg and Bolvig14n=54 (54M)
Age range 18–35
Professional soccer playersAchilles and patellarThickness
Hypoechogenicity
Abnormal: Presence of (1) thickening >1 mm, or (2) hypoechogenicity >1 mm.
Fredberg et al45n=207 (207M)
Mean age 25
Professional soccer playersAchilles and patellarThickness
Hypoechogenicity
Abnormal: Presence of (1) thickness >0.5 mm in the Achilles and patellar tendon, or (2) hypoechogenicity >0.5 mm in the Achilles tendon and >1 mm in the patellar tendon.
Giombini et al12n=37 (15M/22F)
Mean age 27.2
Elite fencersAchilles and patellarThickness
Hypoechogenicity
Vascularity
Abnormal: Presence of (1) increased thickness (undefined), or (2) hypoechogenicity (undefined), or (3) increased vascularity (≥stage 2) as defined by Gisslen et al39
Gisslén et al38n=22 (11M/11F)
Mean age 16.25
Elite junior volleyball playersPatellarThickness
Hypoechogenicity
Vascularity
Abnormal: Presence of (1) increased thickness (undefined), or (2) hypoechogenicity (undefined), or (3) vascularity (≥stage 2) to a defined four-point scale (grade 0–3).
Gisslén et al39n=60 (29M/31F)
Mean age 17.6
Junior volleyball playersPatellarThickness
Hypoechogenicity
Vascularity
Abnormal: Presence of (1) increased thickness (undefined), or (2) hypoechogenicity (undefined), or (3) vascularity (≥stage 2) according to a defined four-point scale (grade 0–3).
Hirschmuller et al15n=634 (425M/209F)
Mean age 41.2
Long-distance runnersAchillesThickness
Hypoechogenicity
Vascularity
Abnormal: Presence of (1) increased thickness (undefined), or (2) hypoechogenicity (undefined), or (3) presence of vascularity according to a defined five-point scale.
Jhingan et al42n=18 (18M)
Mean age 23.5
Elite soccer playersAchillesThickness
Hypoechogenicity
Vascularity
Abnormal: Presence of (1) increased thickness > 1 mm, or (2) hypoechogenicity >1 mm, or (3) paratenon blurring, or (4) vascularity (undefined).
Khan et al40n=45 (27M/18F)
Mean age 42
Patients from a university sports medicine centreAchillesThickness
Hypoechogenicity
Vascularity
Abnormal: Presence of (1) increased thickness >6 mm, or (2) hypoechogenicity (undefined)
Presence of the above features were graded according to a defined three-point scale.
Khan et al16n=30 (30F)
Mean age 24.05
Basketball playersPatellarThickness
Hypoechogenicity
Abnormal: Presence of (1) increased thickness (undefined), or (2) hypoechogenicity (undefined)
Malliaras et al34n=58 (36M/22F)
Mean age 26.1
Elite and recreational volleyball playersPatellarThickness Hypoechogenicity
Vascularity
Abnormal: Presence of (1) increased thickness (undefined), or (2) hypoechogenicity (undefined), or (3) vascularity of at least one vessel in the sagittal plane >1 mm in length.
Ooi et al43n=41 (25M/16F)
Mean age 37.25
Marathon runnersAchillesThickness
Hypoechogenicity
Vascularity
Abnormal: Presence of (1) increased tendon thickness (undefined), or (2) hypoechogenicity (≥grade 2) according to a defined three-point scale (grade 1–3), or (3) vascularity (≥grade 2) according to a defined three-point scale (grade 1–3).
van Ark et al41n=41 (30M/11F)
Mean age 17.2
Elite junior volleyball playersPatellarHypoechogenicityAbnormal: Presence of hypoechogenicity (undefined).
Visnes et al44n=158 (84M/74F)
Mean age 17
Elite junior volleyball playersPatellarThickness
Hypoechogenicity
Vascularity
Abnormal: Presence of (1) hypoechogenicity (undefined), or (2) increased vascularity (≥stage 2) as defined by Gisslen et al (2007)
  • n= sample size; M= Male; F= Female; UTC= Ultrasound tissue characterisation.