TABLE 3.
Outcome measures assessing tendon structure
| Outcome Measure | Frequency in Clinical Trials (n) | Follow up (weeks) | Reliability |
|---|---|---|---|
| STRUCTURE | |||
| Greyscale US – AP Tendon Thickness | 109,39,41,42,46,48-52 | 4, 6, 12, 16, 52, 3.8 years | Test Retest Reliability in healthy adults without lower limb pain or injury: Variation = 0.06(22%)63 Intra-rater Reliability in healthy adults without lower limb pain or injury: Variation = 0.05(19%)63 Inter-rater Reliability in healthy adults without lower limb pain or injury: Variation=0.16(60%)63 |
| Greyscale US – Pathology (Yes/ No) | 333,47,48 | 12, 28 months, 3.8 years | Test Retest Reliability in patients with chronic mid-portion Achilles tendinopathy: CV=1.147 |
| Greyscale US - 4 Point Pathology Grading Scale | 146 | 12, 52 | Inter-rater Reliability in patients with chronic mid-portion Achilles tendinopathy: κ = <0.446 |
| Doppler US - Colour Fraction Measurement (%) | 139 | 12, 52 | Not reported |
| Doppler US - Ohberg Score (0-2) | 147 | 28 months | Test Retest Reliability in patients with chronic mid-portion Achilles tendinopathy: CV=1.147 |
| Doppler US - Modified Ohberg Score (0-4) | 59,40,41,43,53 | 0, 6, 12, 24, 52, 5 years | Inter-rater Reliability in patients with chronic mid-portion Achilles tendinopathy: ICC=0.8564 |
| UTC - % of Type 1-4 Echoes | 215,42 | 2, 6, 8, 16, 24, 52 | Intra-rater Reliability in patients with chronic mid-portion Achilles tendinopathy: ICC=0.95-0.9965 |
| MRI - 4 Point Scale of Intratendinous Signal | 114 | 12, 14 months, 4.2 years | Intra-rater Reliability in patients with chronic mid-portion Achilles tendinopathy: κ=0.5814 Inter-rater Reliability in patients with chronic mid-portion Achilles tendinopathy: κ=0.7114 |
| MRI - Mean Signal (Units) | 111 | 12 | Intra-rater Reliability in patients with chronic mid-portion Achilles tendinopathy: r=0.84-0.9711 Inter-rater Reliability in patients with chronic mid-portion Achilles tendinopathy: r=0.78-0.9511 |
| MRI - Tendon Volume | 211,14 | 12, 14 months, 4.2 years | Intra-rater Reliability in patients with chronic mid-portion Achilles tendinopathy: r=0.98-0.9911,14 Inter-rater Reliability in patients with chronic mid-portion Achilles tendinopathy: r=0.96-0.9911,14 |
| PARA-TENDINOUS SUBSTANCES | |||
| Micro-dialysis - Intratendinous Glutamate | 138 | 12 | Not Reported |
| Micro-dialysis - Interstitial PICP from paratendinous space just ventral to the Achilles tendon (Collagen synthesis) | 145 | 12 | Intra-rater Reliability in patients with chronic mid-portion Achilles tendinopathy: CV=2.7% at 214 μg/L45 |
| Micro-dialysis - Interstitial ICTP from paratendinous space just ventral to the Achilles tendon (Collagen Degradation) | 145 | 12 | Intra-rater Reliability in patients with chronic mid-portion Achilles tendinopathy: CV=4.9% at 6.1 μg/L45 |
| TENDON/ PARATENON MICROCIRCULATION | |||
| Tendon and Paratenon Microcirculation using non-invasive combined laser-Doppler and Flowmetry systems | 144 | 12 | Intra-rater Reliability in healthy adults without lower limb pain or injury: CV=5%66 Inter-rater Reliability in healthy adults without lower limb pain or injury: CV=32-37%66 |
AP = anterior-posterior; US = ultrasound; UTC = ultrasound tissue characterisation; MRI = Magnetic resonance imaging; PICP = interstitial carboxyterminal propeptide of type I collagen; ICTP = interstitial carboxyterminal telopeptide region of type I collagen; CV = coefficient of variance