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.

Deep gluteal syndrome is an increasingly recognized disease entity, caused by compression of the sciatic or pudendal nerve due to non-discogenic pelvic lesions. It includes the piriformis syndrome, the gemelli-obturator internus syndrome, the ischiofemoral impingement syndrome, and the proximal hamstring syndrome. The concept of the deep gluteal syndrome extends our understanding of posterior hip pain due to nerve entrapment beyond the traditional model of the piriformis syndrome. Nevertheless, there has been terminological confusion and the deep gluteal syndrome has often been undiagnosed or mistaken for other conditions. Careful history-taking, a physical examination including provocation tests, an electrodiagnostic study, and imaging are necessary for an accurate diagnosis.

After excluding spinal lesions, MRI scans of the pelvis are helpful in diagnosing deep gluteal syndrome and identifying pathological conditions entrapping the nerves. It can be conservatively treated with multidisciplinary treatment including rest, the avoidance of provoking activities, medication, injections, and physiotherapy.

Endoscopic or open surgical decompression is recommended in patients with persistent or recurrent symptoms after conservative treatment or in those who may have masses compressing the sciatic nerve.

Many physicians remain unfamiliar with this syndrome and there is a lack of relevant literature. This comprehensive review aims to provide the latest information about the epidemiology, aetiology, pathology, clinical features, diagnosis, and treatment.

Cite this article: Bone Joint J 2020;102-B(5):556–567.

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.