Arthroscopic Surgical Procedures vs Sham Surgery for Patients With Femoroacetabular Impingement and/or Labral Tears.

Inclusion Criteria: * hip pain during daily and/or spor t ing activities; * intra-articular hip pain with radiological signs of FAI and/or labral tears eligible for hip arthroscopy (to be determined in a pragmatic fashion by the surgeon based on clinical examination and imaging * the patient is able to give written informed consent and to participate fully in the interventions and follow-up procedures Exclusion Criteria: * pain that is not confirmed by physical examination of the hip * evidence of preexisting osteoarthritis, defined as Tonnis grade \>1, or less than 3mm superior joint space width on AP pelvic radiograph * center edge angle on radiograph \<25°; (v) previous known hip pathology such as Perthes' disease, slipped upper femoral epiphysis or avascular necrosis * previous hip injury such as acetabular fracture, hip dislocation or femoral neck fracture * previous hip surgery * medical conditions complicating surgery (ASA 3); (ix) inflammatory joint disease (RA, Bechterew etc) * physical inability to undertake testing procedures * expected lack of compliance such as cognitive impairment, drug abuse or similar; * inability to understand the written and spoken language of the treatment centre; * contra-indications to placebo surgery, which will include large loose body, chondral flap \>1cm2 detached at 3 sides, complete labral radial flap tear and labral bucket-handle tear with complete avulsion \>1.5cm long