Re: Ultrasound-guided platelet-rich-plasma injection for distal biceps tendinopathy

We would like to congratulate Barker et al. for their original article, Ultrasound-guided platelet-rich-plasma injection for distal biceps tendinopathy.¹ They describe a group of patients with a relatively uncommon but difficult to treat problem of the elbow. In their introduction, however, they state that there were no other or previous reports concerning platelet-rich-plasma injections for distal biceps tendinopathy.

We would like to draw attention to our article that was published at the end of 2014, Single injection of platelet-rich plasma (PRP) for the treatment of refractory distal biceps tendonitis: long-term results of a prospective multicenter cohort study.² It appears that both series were published at about the same time, independent from each other, in different journals.

In our article, we described a prospective cohort of twelve patients from two large tertiary referral hospitals who were recruited over a period of 20 months. Clinical diagnosis of distal biceps tendonitis was confirmed using magnetic resonance imaging. All patients had a single US-guided injection of PRP carried out by the two senior authors. Patients were objectively assessed for clinical and functional improvement using visual analogue (VAS) rest and activity pain scores, subjective satisfaction scale, elbow functional assessment (EFA) and isometric muscular (biceps) strength. Symptom severity and subsequent functional outcome were measured pre-injection and at final follow-up. At a median follow-up of 47 months (36 months to 52 months, all patients showed significant improvement in pain (p < 0.002) and functional outcome (p < 0.004). Median resting VAS score improved from 6 (3 to 8) to 0.5 (0 to 2) and the activity VAS score improved from 8 (6 to 9) to 2.5 (0 to 4). EFA improved from 63 to 90. In the English cases, isometric muscular strength also showed significant improvement (in the Dutch cases, this was not tested). All patients were satisfied with the clinical and functional outcomes at final follow-up.

We consider that both articles show that there is a positive effect of the injection of platelet-rich-plasma in treating distal biceps tendinopathy and that, despite the controversial results of platelet-rich-plasma injections in other tendinopathies, there appears to be a place for this treatment. However, to reach a higher level of evidence, a prospective randomized controlled trial needs to be performed. We would like to challenge the authors to design this global multicentre prospective randomized controlled trial in which we of course will participate.