Test-retest reliability and the minimal detectable change of clinical and structural outcomes in athletes with patellar tendinopathy.

Objectives

To establish test-retest reliability and minimal detectable change (MDC) values for outcomes in patients with patellar tendinopathy.

Design

Test-retest reliability study.

Setting

Hospital.

Participants

Thirty participants (29.6 years, 77% males) underwent two test days with a 7-day hiatus. MAIN OUTCOME MEASURES Single-leg decline squat (SLDS), VISA-P, pain pressure threshold (PPT), and ultrasound measurements (tendon thickness and Power Doppler (PD) activity). Data was analyzed using intraclass correlation coefficient (ICC) and MDC performed on standard deviation (SD) of pooled and change scores.

Results

The SLDS showed ICC values ranging from 0.86 to 0.92 with a MDC95 ranging from 0.91 to 2.46 on the numeric rating scale for SDchange and SDpooled. For the VISA-P, the ICC was 0.93 with a MDC95 of 6.05 and 11.81 for SDchange and SDpooled. PPT resulted in an ICC of 0.91 and MDC95 of 69.37 and 117.06 kPa for SDchange and SDpooled. Tendon thickness showed an ICC of 0.98 and MDC95 of 0.29 and 1.01 mm for SDchange and SDpooled. PD activity showed an ICC of 0.80, and MDC95 of 11.95 and 18.78 mm2 for SDchange and SDpooled.

Conclusions

The SLDS, VISA-P, PPT, tendon thickness, and PD activity demonstrated good-to-excellent relative reliability in individuals with PT; however, absolute measurement precision was limited.