In 1902 Shenton described his “line” which, “is formed by the outlines of the upper margin of the obturator foramen and the inner margin of the neck of the femur” stating, “broken continuity of which infallibly indicates displacement or trouble in the hip region. Some 110 years later with significant advancements in Radiology, we assessed whether there is still a role in modern Orthopaedics.

We reviewed 900 anterior-posterior bilateral hips on pelvis radiographs and noted whether Shenton's line was intact or broken. We recorded the presence or absence of pathology in each hip along with age and sex of the patient. In addition 15 independent observers were asked to blindly independently review 15 pelvic radiographs on two separate occasions. They noted whether Shenton's line was intact or disrupted. From this data we analysed the intra and inter-observer reliability.

1547 hips were analysed. 63% (971/1547) had an intact Shenton's line, 37% (576/1547) had a disrupted line. Of 271 femoral neck fractures, 44 (16%) were seen to have an intact Shenton's line. Regarding other pathologies, 2% of osteoarthritic hips, 0.1% of dysplastic hips and 20% of prosthetic hips had a disrupted Shenton's line. No ‘normal’ hips had a broken line. There was significant inter-observer error yet little intra-observer error found.

Our evidence reaffirms Shenton's original work. With a disrupted line there is a high probability of pathology within the hip. However, there may still be a fracture with an intact line, suggesting that Shenton's line is highly sensitive yet not greatly specific.

Pre-operative templating has become an essential aspect of pre-operative preparation for elective total hip replacement. The techniques involved have evolved from acetates used with analogue radiographs to digital processes. This study audits the accuracy of the TraumaCad software in total hip replacement since its introduction at two centres in the same trust.

The pre and post-operative radiographs of 40 patients undergoing total hip replacement by a single surgeon at a district general hospital were retrospectively reviewed. Patients that had templating of their digital Picture Archiving and Communications Systems (PACS) pelvic images using the TraumaCad software programme (Orthocrat Ltd, Petach-Tikva, Israel) were included. The templated acetabular component and femoral stem was compared to the actual size of acetabular and femoral prostheses inserted at surgery.

The acetabulum was accurately templated in 38.9% of the hips and within ± 1 size in a further 44.4% (total 83.3%). The femoral stem size was accurate in 27.8% of the hips and within ± 1 size in a further 52.8% of the hips (total 80.6%). Such a variation is likely due to the variable positioning of the calibration ball.

TraumaCad is a useful tool in the pre-operative templating of hips successfully predicting the prosthesis components within ± 1 size in the majority of hips studied. However, it should not be relied upon as an absolute measurement of the size of prosthesis to be used, rather be used as a suitable guide to intra-operative stages such as the femoral neck cut position.

We examined the position of the superior gluteal nerve in forty-four cadaveric hips in relation to the greater trochanter and the acetabulum . We found that the nerve lay a mean of 4.8 centimetres from the greater trochanter with a range of two to nine centimetres and a mean of 3.2 centimetres from the acetabulum. The nerve was visibly damaged in three out of forty-four hips following direct lateral approach. Our study does not support the “safe zone” proximal to the greater trochanter and suggests the proximity of the nerve to the acetabulum as a potential cause of nerve injury.

Abductor weakness following the direct lateral approach to the hip is well described and is associated with damage to the superior gluteal nerve on neurophysiological testing in from 23–26 %. A “safe zone” has been described of up to five centimeters proximal to the greater trochanter.

We examined forty-four cadaveric hips exposed by the direct lateral approach by surgeons not directly involved with the study. We measured the position of the superior gluteal nerve in relation to the greater trochanter, the acetabulum and the margin of the skin incision. We examined the nerve for visible signs of damage.

We found the position of the superior gluteal nerve to be a mean of 4.8 centimeters from the greater trochanter (range two to nine), 3.2 centimeters from the superior margin of the acetabulum (range one to eight), and 4.1 centimeters from the margin of the skin incision. There was visible damage to the nerve in three of forty-four cases.

Neurophysiological studies show subclinical damage to the superior gluteal nerve in up to 77% of cases following direct lateral approach to the hip and in association with abductor weakness in 23–26%. Our study does not support the notion of a “safe zone” of five centimetres proximal to the greater trochanter, and with a mean of 4.8 centimetres the zone is unsafe more often than it is safe. The proximity of the superior gluteal nerve to the superior margin of the acetabulum suggests that it may be damaged by retractor placement at this site.