Purpose: The aim of the study was to assess the use of thecentre-edge (CE) angle in the assessment of pincer femoro-acetabular impingement (FAI) for reliability and predictability in the diagnosis.

Methods: Between 2004 and 2008, 55 patients underwent surgical treatment for FAI. A control group of 30 was identified among patients attending the emergency department with normal radiographs. Radiographs were assessed by two independent observers both before and after the operation. Nine patients with trauma were excluded. The magnetic resonance arthrogram reports of the remaining 46patients were assessed for pincer FAI. Nineteen patients were identified and underwent repeat radiographic assessment. All underwent surgical dislocation of the hip (SDH), acetabular, with/without femoral osteochondroplasty. Acetabular depth and version were also assessed. The intraclass correlation (ICC) was used to assess the reliability of the CEangle. The paired t-test and independent groups t-test were used to assess the difference between the pincer FAI group, both pre-op and post-op, and against controls.

Results: The control and pincer groups were similar in demographics (p=0.1769). Coxa profunda was present in14 patients, with eight also having retroverted acetabuli. Of the rest, two had retroverted acetabuli and one protrusio. The mean CE angle in the control group was 31.4°, in thepre-op pincer group 46.2° and in the post-op pincer group38.3°. The ICC for intra-observer correlation was 0.977 and0.992 pre-op and 0.986 and 0.974 post-op. The ICC forinter-observer correlation was 0.960 and 0.957 pre-op and0.979 and 0.967 post-op. The p-value was <0.001 between the controls, the pre-op and post-op pincer groups. The test characteristics using the CE angle ≥40 is a reasonably good predictor of FAI, with a sensitivity of 84.2% and a specificity of 100%.

Conclusions: The pincer FAI can be reliably assessed with the CE angle and can be predicted in patients presenting with FAI.

Satish Kutty is a highly proficient and qualified consultant trauma and orthopaedic surgeon who possesses expertise in hip replacement surgery, knee replacement surgery, and hip arthroscopy alongside joint injections, knee arthroscopy, and knee osteoarthritis. He practises at one of the leading private hospitals in the UK, the Rivers Hospital in Sawbridgeworth.

Notably, Mr Kutty completed his orthopaedic training in Wales. Following this, he took up the opportunity to successfully undertake multiple fellowships in Austria, Switzerland, Germany and a lower limb joint reconstruction fellowship at The University of Calgary in Canada. All these fellowships were linked to awards from the British Orthopaedic Association, British Hip Society, AO and The Royal College of Surgeons of England. His other main areas of interest include hip pain, failed joint replacements and sports injuries of the hip, as well as complex primary hip replacements.

He is currently the Surgical Tutor of the Royal College. He is also the Lead Educational Supervisor – in charge of Orthopaedic training at Princess Alexandra Hospital. He is currently the Chair of the Education Committee of The British Hip Society and also the Chair of the website committee of SICOT.