Extracorporeal shockwave therapy for refractory greater trochanteric pain syndrome

Greater trochanteric pain syndrome is a disorder that affects the (lateral) side of the hip or hips. Greater trochanteric pain may be associated with inflammation of the trochanteric bursa (also known as trochanteric bursitis). The trochanteric bursa is a small fluid-filled sac that separates the greater trochanter of the femur and the overlying fascia lata to allow smooth movement. Greater trochanteric pain may also be associated with direct injury, tendon damage, infection, differences in leg length or hip-replacement surgery.

Greater trochanteric pain syndrome is usually managed conservatively with rest, physiotherapy, anti-inflammatory medication and corticosteroid injections (often combined with local anaesthesia). In patients refractory to conservative treatments, surgical options such as supratrochanteric fasciotomy or trochanteric bursectomy may be used.

Extracorporeal shockwave therapy (ESWT) is a non-invasive treatment in which a device is used to pass acoustic shockwaves through the skin to the affected area. Ultrasound guidance can be used to assist with positioning of the device.

ESWT may be applied in one or several sessions. Local anaesthesia may be used because high-energy ESWT can be painful. Different energies and frequencies of shockwaves can be used.

The mechanism by which this therapy might have an effect on greater trochanteric pain syndrome is unknown.

A non-randomised comparative study of 229 patients treated by several ESWT sessions (n=78), a single local corticosteroid injection (n=75) or 'home training' (n=76) reported that the percentage of patients who had either recovered completely or had improved symptoms (assessed using a 6-point Likert scale) following ESWT were 13% (10 out of 78) at 1 month, 68% (53 out of 78) at 4 months and 74% (58 out of 78) at 15 months. In the corticosteroid injection group, 75% (56 out of 75) of patients reported complete recovery or improved symptoms at 1 month, 51% (38 out of 75) at 4 months and 48% (36 out of 75) at 15 months. In the home-training group, 7% (5 out of 76) of patients reported complete recovery or improved symptoms at 1 month, 41% (31 out of 76) at 4 months and 80% (61 out of 76) at 15 months.

The non-randomised comparative study of 229 patients reported significantly higher mean pain scores (measured on a visual analogue scale from 0 to 10; 10 indicates worst conceivable pain) in the ESWT (5.6) and the home-training groups (5.9) compared with the steroid injection group (2.2) at 1 month (p<0.001). However, at 15 months, the scores were 2.4 after ESWT, 2.7 after home training and 5.3 after injection (p<0.001). All groups had similar pain scores at baseline (range 5.8 to 6.3).

The non-randomised comparative study of 229 patients reported that 64% (50 out of 78) of patients in the ESWT group, 49% (37 out of 75) in the steroid injection group and 34% (26 out of 76) in the home-training group had returned to previous sporting or recreational activity at 4 months (ESWT versus home training, p<0.001).

The Specialist Advisers listed key efficacy outcomes as recovery measured on a 6-point Likert scale, severity of pain measured using a visual analogue scale and improved function.

Increased pain for more than 1 day was reported in 3% (2 out of 78) of patients treated by ESWT, 24% (18 out of 75) treated by steroid injection and 20% (15 out of 76) treated with home training in the non-randomised comparative study of 229 patients.

Skin irritation during the first month of follow-up was reported in 33% (26 out of 78) of patients treated by ESWT and 3% (2 out of 75) treated by steroid injection in the non-randomised comparative study of 229 patients.

The Specialist Advisers considered theoretical adverse events to include pain, tendon rupture, haematoma and nerve damage.

NICE received 30 completed questionnaires from patients treated by the procedure. Thirty percent (9 out of 30) stated that they would not have ESWT again; 3 of these patients reported that the procedure had made their condition worse with increased pain and decreased mobility. The remaining 70% (21 out of 30) of patients would recommend this procedure to others.