Introduction

Accurate acetabular position is an important goal during THA. It is also well known that accurate acetabular positioning is very frequently not achieved, even by experienced, high volume surgeons. Problems associated with cup malposition are: dislocation, accelerated poly wear, impingement, ceramic squeaking, metalosis. Murray et al described 3 methods of measurement and assessment of acetabular inclination and anteversion (I&A): anatomic, radiographic and operative. It is the hypothesis of the authors, that the differences and details of these 3 methods are poorly understood by many surgeons and this is contributory to inconsistent cup positioning. Additionally, the radiographic method, which is most commonly used for post op assessment and academic studies, contributes to misunderstanding and error. Modern computer guidance and software assessment of radiographs allows us to easily measure anatomic I&A which should be thought of as “true” I&A.

Using a prospective database of 1309 displaced acetabular fractures gathered between 1980 and 2007, we calculated the annual mean age and annual incidence of elderly patients > 60 years of age presenting with these injuries. We compared the clinical details and patterns of fracture between patients > 60 years of age (study group) with those < 60 years (control group). We performed a detailed evaluation of the radiographs of the older group to determine the incidence of radiological characteristics which have been previously described as being associated with a poor patient outcome.

In all, 235 patients were > 60 years of age and the remaining 1074 were < 60 years. The incidence of elderly patients with acetabular fractures increased by 2.4-fold between the first half of the study period and the second half (10% (62) vs 24% (174), p < 0.001). Fractures characterised by displacement of the anterior column were significantly more common in the elderly compared with the younger patients (64% (150) vs 43% (462), respectively, p < 0.001). Common radiological features of the fractures in the study group included a separate quadrilateral-plate component (50.8% (58)) and roof impaction (40% (46)) in the anterior fractures, and comminution (44% (30)) and marginal impaction (38% (26)) in posterior-wall fractures.

The proportion of elderly patients presenting with acetabular fractures increased during the 27-year period. The older patients had a different distribution of fracture pattern than the younger patients, and often had radiological features which have been shown in other studies to be predictive of a poor outcome.

There remains uncertainty about the most effective surgical approach in the treatment of complex fractures of the acetabulum. We have reviewed the experience of a single surgeon using the extended iliofemoral approach, as described by Letournel.

A review of the database of such fractures identified 106 patients operated on using this approach with a minimum follow-up of two years. All data were collected prospectively. The fractures involved both columns in 64 (60%). Operation was undertaken in less than 21 days after injury in 71 patients (67%) and in 35 (33%) the procedure was carried out later than this. The reduction of the fracture was measured on plain radiographs taken after operation and defined as anatomical (0 to 1 mm of displacement); imperfect (2 to 3 mm) or poor (> 3 mm). The functional outcome was measured by the modified Merle d’Aubigné and Postel score. The mean follow-up was for 6.3 years (2 to 17).

All patients achieved union of the fractures. The reduction was graded as anatomical in 76 (72%) of the patients, imperfect in 23 (22%), and poor in six (6%). The mean Merle d’Aubigné and Postel score was 15 (5 to 18) with 68 patients (64%) showing good or excellent and 38 (36%) fair or poor results. Function correlated significantly with the accuracy of the reduction (p < 0.009). Significant heterotopic ossification developed in 32 patients (30%) and was associated with a worse mean Merle d’Aubigné and Postel score of 13.7.

The extended iliofemoral approach can be performed safely in selected complex acetabular fractures with an acceptable clinical outcome and rate of complications. Effective prophylaxis against heterotopic ossification should be strongly considered.

Purpose: A classification system for fractures is an important communication tool for surgeons allowing the development of management schemes as well as an estimation of the prognosis. The purpose of our work was to evaluate the inter- and intra-observer reproducibility of the Letournel classification system for acetabular fractures.

Material methods and results: Sixty-five x-rays (AP and Judet views) and computed tomography (CT) series were chosen at random from a data base containing 800 fractures. The distribution of the fracture types followed data in the literature. Three groups of observers were formed, each composed of three orthopaedic surgeons. Group 1 included surgeons who had studied with Letournel, group 2 surgeons specialised in acetabular fractures, and group 3 surgeons qualified for general traumatology surgery. The kappa coefficient was determined to assess agreement between observers. Each observer read the images twice without knowledge of the treatment. The observers first classed the fractures using the x-rays alone then with the x-rays in combination with the CT. Two sessions were organised, two months apart to avoid any possible memorisation. Reproducibility without then with CT for the first session were: group 1: 0.07 and 0.74; group 2: 0.71 and 0.69; group 3: 0.51 and 0.512. Results were similar in the second session. Intra-observer reproducibility without then with CT was: group 1: 0.80 and 0.83; group 2 0.80 and 0.80; group 3: 0.64 and 0.69. Among the six more experimented observers (groups 1 and 2), 100% agreement was found for 66% of the x-rays compared with 22% for the new observers.

Discussion and conclusion: The Letournel classification system using x-rays in combination or not with CT is reliable (kappa > 7) for properly trained surgeons with regular experience in treating acetabular fractures. The value of the CT in the assessment of acetabular fractures is well established for identifying detached elements and joint crush. Conversely, CT does not appear to be essential to class ace-tabular fractures. The Letournel classification can be used as a reliable tool for the description of acetabular fractures and taught to surgeons desiring to undertake regular treatment of these fractures.

We have studied prospectively the effect of indomethacin on the development of heterotopic ossification (HO) after the internal fixation of acetabular fractures. After operation 107 patients randomly received either a six-week course of indomethacin or no treatment against HO. Plain radiographs of 101 patients at a mean of 7.9 months after surgery showed HO in 47.4% of the 57 patients who received indomethacin and in 56.8% of the 44 who did not. This difference was not statistically significant. Heterotopic ossification of Brooker class II or more was seen in four patients (7%) with prophylaxis and in one without (p = 0.51).

Measurements of the volume of HO on 3-D CT reconstructions showed a median value of 1.5 cm³ in patients with indomethacin and 4.0 cm³ in those without (p = 0.28). When only the 57 patients in whom the operation was carried out through either a Kocher-Langenbeck or an extended iliofemoral approach were included the indomethacin group showed a median volume of 1.7 cm³ compared with 3.6 cm³. On plain radiographs Brooker class II or above was seen in 9.4% of the patients receiving indomethacin and in 4.8% of those who did not.

Indomethacin was therefore not effective in preventing ectopic bone formation after surgery for acetabular fractures. There was a significant association of male gender with volume of HO using a non-parametric analysis of variance.