Twenty-two patients with piriformis syndrome underwent surgery between October 1995 and February 2002. The mean age was 56 years (range 28-90). Only 2 patients (9%) gave a history of trauma to the ipsilateral buttock. All the patients complained of deep buttock pain, which radiated to the ankle in 14 (63%), the calf in 4 (18%) and the thigh in 3 patients (13.6%). The symptoms were chronic, with a mean of 70 months (range 12-192) and patients had been previously seen by a mean of 2.6 specialists (range 1-6). There was associated neurosensory loss in 11 patients (50%). The symptoms were exacerbated by passive stretching and active contraction of the piriformis muscle. MRI of the lumbar spine (every case) and gluteal region (8 cases) were negative, while NCV tests (20 cases) were positive in 11 patients (55%). Previous conservative measures such as physiotherapy (59%) and epidural (40%) had failed. Every patient had surgical division of the piriformis tendon at the greater trochanter by the senior author. Abnormal anatomy was identified in 6 cases (29%).

At 6 weeks (n=22), the symptoms had resolved in 6 patients (27%), were better in 8 (36%), no different in 7 (32%) and worse in 1 (4.5%). After a mean follow-up of 52 months (range 11-86), seven (35%) of patients were cured, 3 (15%) were better, 8 (40%) were no different, 2 (10%) were worse than pre-operatively and 2 had died of unrelated causes. Seventy-five percent of patients said that with hindsight they would undergo surgery again. One patient suffered a post-operative below knee DVT requiring no treatment.

Surgery for piriformis syndrome in this selected group of patients led to an improvement or resolution of chronic symptoms in 64% of patients at 6 weeks, and 50% of patients after a mean follow-up of 52 months with minimal associated morbidity.

The aim of this review is to evaluate the current available literature evidencing on peri-articular hip endoscopy (the third compartment). A comprehensive approach has been set on reports dealing with endoscopic surgery for recalcitrant trochanteric bursitis, snapping hip (or coxa-saltans; external and internal), gluteus medius and minimus tears and endoscopy (or arthroscopy) after total hip arthroplasty. This information can be used to trigger further research, innovation and education in extra-articular hip endoscopy.