Aim Patella tendinopathy is a common cause of knee pain in athletes, with limited treatment options once rehabilitation methods have failed. We conducted a double blind randomised controlled study to assess the efficacy of Autologous Blood Injections (ABI) against saline in patients with chronic recalcitrant patella tendinopathy.

Methods Patients with a diagnosis of refractory patellar tendinopathy were recruited between March 2010 and March 2012. Diagnosis was confirmed on ultrasound. All patients completed the Short-form McGill pain questionnaire (MPQ), a visual analogue scale (VAS) and a VISA-P scale. Using two practitioners, patients were randomised to either receive autologous blood or saline injections. All patients were followed up for 12 months with repeat assessments.

Results 22 patients completed the final review at 12-months and were included in the study. Subjects ranged in age from 22 and 61 years and were randomised to 11 in each autologous blood (ABI) and saline groups. ABI group had a mean duration of symptoms of 16.7 months whilst that of the saline group was 19.2 months. The saline group mean VAS score was reduced from 7.9 to 4.5 at 1 month (p=0.003) and 3.3 (p=0.005) at one year. With ABI, the score was reduced from 7.5 to 4.5 (p=0.005) at 1 month and 3.1 (p=0.003) at one year. VISA-P, MPQ and VAS scores were all significant in both groups.

Conclusions This study demonstrated that both the ABI and saline groups experienced a significant improvement in symptoms. However, when the results were compared there was no statistical difference between the two groups. This research provided an argument that it is the tendon fenestration that provides the therapeutic effect rather than the substance being injected.