Greater trochanteric pain syndrome is a painful condition characterised by pain around the greater trochanter usually affecting middle-aged women. The majority of patients will improve with conservative management such as physiotherapy and non-steroidal anti-inflammatory drugs (NSAIDs); however, if this fails then more invasive treatments including corticosteroids and surgery may be required. Platelet-rich plasma (PRP) is an autologous blood product, which has a higher concentration of growth factors postulated to provide enhanced healing and anti-inflammatory properties. The Hip Injections PRP Vs Placebo (HIPPO) trial aims to assess the ability of ultrasound-guided PRP injections to improve symptoms and function in patients with GTPS.

64 patients were enrolled and randomised to either the PRP or placebo (normal saline) treatment arm. Two patients decided to drop out of the trial. Clinical outcomes in both groups were evaluated and compared using the International Hip Outcome Tool-12 (iHOT12), Visual Analogue Scale (VAS) of pain, the modified Harris Hip Score (mHHS) and the presence or absence of complications at 3 and six months. The level of significance was set at p<0.05. Both groups received physiotherapy after the injections.

The mean age was 57.5. There were 6 males and 56 females with M:F ratio of 1:9.3. Both groups were similar in terms of demography and preoperative scores. The iHOT12 score improved from 28.23 to 45.42 at three-months and decreased slightly to 42.44 at six-months in the Placebo group. The iHOT12 in the PRP group improved from 35.51 to 44.47 at three-months and decreased to 39.78 at six-months. Both groups showed improved VAS and mHHS at three-months compared to the baseline with no statistically significant difference between the two groups (p >0.05). The scores decreased at six-months however remained above the baseline. No complications were reported. Gender and age had no effect on outcomes.

Both groups similarly improved from baseline. Physiotherapy can be considered as an important factor in patients' treatment. Further research should be conducted to investigate the role of physiotherapy in the treatment of GTPS.