Session I - Pelvic Trauma

Acetabular Fractures: Operative Management and Long Term Results

Gholam S. Pajenda, MD; Mehdi Mousavi, MD; Alexander Kolonja, MD; Vilmos Vécsei, MD, University Clinic for Traumatology, Vienna University Hospital, Waehringer Gaertel, Vienna, Austria

Introduction: Displaced acetabular fractures are one of the most challenging injuries that trauma surgeons have to deal with. Surgical treatment is undertaken in most displaced acetabular fractures, especially in young adults. These fractures are often associated with visceral and other skeletal injuries that complicate their treatment and in some cases delay their diagnosis. In this follow-up study we investigated the relation between the fracture type and degree of surgical reduction observed radiographically with respect to complication rates and functional outcome. Our goal was to obtain a more quantitative understanding of expected long-term outcome of patients based on early radiographic findings.

Material and Methods: Between 1972 and 1996, 209 patients, 127 male and 82 female, with a mean age of 38 years (range 15 to 62 years), were treated for displaced acetabular fractures with open reduction and internal fixation (ORIF) at the Vienna University Clinic for Traumatology. Of these patients 143 (68 %) had been injured in automobile accidents, 20 (10 %) in motorcycle accidents, 19 (9 %) as pedestrians; 18 patients (9 %) fell from a great height and 9 (4 %) had an unknown cause of injury. Sixty three (30 %) of all patients had multiple injuries. Of these patients, 161 could be followed up over a period of 2-20 years.

Pre-Operative Management: After admission the extent of the injuries to each patient was evaluated and the appropriate treatment performed to stabilize the hemodynamic condition. Plain anterior posterior, obturator oblique and iliac oblique radiographs of the pelvis were obtained. In the last 15 years CT-Scans have also been obtained. Every grossly dislocated fracture was reduced with an image intensifier.

The fractures were classified according to the scheme of Letournel and Judet and the operative approach selected. Depending on their associated injuries, most patients were operated on within two weeks following their injury. A condylar femoral traction, whenever necessary, combined with lateral traction, was applied until the time of the operation. Internal fixation was applied immediately only in cases of associated irreducible and unstable femoral head dislocation fractures (Pipkin IV), open fractures, primary sciatic nerve lesions and in associated injuries to the pelvic organs.

Operative Management: Depending on the fracture type, the following approaches were made: posterior approach (Kocher-Langenbeck) in posterior column fractures (n = 76); lateral approach (Lexer-Ollíer) in posterior column and combined posterior wall and transverse fractures (n = 39); anterior ilioinguinal approach in anterior column and transverse fractures (n = 20); and the combined anterior and posterior approach (Letournel) in both column fractures (n = 26), through which a global view of the hip joint, was achieved (6, 8). In 2 cases percutaneous screwing was performed in posterior wall fractures. A trochanteric Schanz pin inserted in the greater trochanter was used to expose the articular surface of the acetabulum and femoral head. Whenever greater exposure was necessary, in particular in patients with extensive comminution of the acetabular dome, a trochanteric osteotomy was performed. The implants used for stabilization of fractures were: screws in 43 cases (27 %), DC and reconstruction plates in 71 cases (44 %), and a combination of plate and screw in 47 cases (29 %).

Postoperative Management: On the third postoperative day passive and active exercises were begun on all patients depending on the concomitant injuries and their general condition. Walking on crutches with partial weight bearing (10 - 15 kg) was allowed between 6 to 12 weeks after surgery followed by full weight bearing between the 12th and 16th postoperative week.

Clinical and Radiographic Evaluation: One hundred sixty-one of our patients could be followed-up over a period ranging between 2 to 20 years. Each patient was evaluated both clinically and radiographically. The radiographs were compared with those taken at 3-month intervals within the first year. The reduction was termed anatomic when there was less than 1 mm of displacement at the articular surface on any of the postoperative radiographs; satisfactory, if there was no more than 3 mm of displacement; and unsatisfactory, when the displacement was greater than 3 mm according to Matta. For the functional evaluation of the hip joint we used the scheme of Merle d' Aubigne as recommended by Letournel. In the last 5 years we also used the Harris hip score, which is based on the variables of pain, function, absence of deformity, and range of motion. No significant difference could be observed between the two scores in the clinical evaluation of the hip joint.

To obtain an objective view of our data, we compared the long-term outcomes of each fracture type, based on the classification of Letournel and Judet, to the functional evaluation of each patient, based on their Merle d´hip score. The quality of surgical reduction was also evaluated according to the suggestions of Matta.

Results: Patients suffering fractures that did not include the articulating surface of the acetabulum, column fractures, had considerably better outcomes than individuals suffering fractures involving the acetabular walls. The best results were seen in patients with single column fractures (90 % excellent or good) and the worst in patients whose fracture pattern included a transverse pattern (62 % good or excellent). Transverse fractures demonstrated a normal distribution of outcome with the majority of patients falling in the good or fair category. No episode of non-union was observed in any of the fracture patterns. The results of the over all clinical and radiographical evaluation are presented in table 2. The highest rates of complications were observed in both column and in transverse with posterior wall fractures.

Osteoarthritis was seen in 32 patients (20%). According to the Heeg classification of osteoarthritis, good and fair grades (minimal joint narrowing, spur formation and sclerosis) were observed in 21 patients (13%) and a poor result (severe joint narrowing, severe spur formation and subchondral cyst formation) in 11 patients, which led subsequently to total hip arthroplasty.

Avascular femoral head necrosis was seen in 9 patients (6%) 4 cases in both column fractures, 3 case in transverse and posterior wall, and 2 cases in transverse fractures. No correlation was found between the incidence of femoral head necrosis and the operative approach.

Heterotopic ossification was seen in 15 patients (9 %) 4 type I-II, and 11 type III-IV according to the Brooker classification. Posterior approach (Kocher-Langenbeck) and the combined anterior & posterior approach (Letournel) in combined transverse and posterior wall fractures, posterior column fractures and both column fractures respectively, showed a higher incidence of heterotopic ossification.

Primary sciatic nerve palsy was seen in 10 patients (6%) and postoperative peroneal nerve palsy in 6 patients (4%), all of which improved during the rehabilitation period.

Deep late infection was observed in 6 cases (4%) with a higher incidence in the posterior approach. These were treated by revision and local application of antibiotics. Two cases ended up in femoral head resection (girdlestone procedure). Superficial wound infection was observed in 8 cases (6%), which healed up after local revision and systemic antibiotic therapy.

Discussion: Acetabular fractures are often associated with multiple trauma and yield more satisfactory results with early operative reduction. Similar to all the other articular fractures, open reduction and internal fixation is required in most displaced fractures of the acetabulum that involve its main weight-bearing structures. The degree of residual displacement is the key prognostic factor in determining the quality of the outcome.

In 1964 Judet et al recommended ORIF for all displaced acetabular fractures and showed a close correlation between the clinical result and the quality of reduction achieved. In 1986 Matta introduced the concept that the percentage of the intact dome could be used to determine whether to manage a fracture nonoperatively. If a 45° angle was maintained in the dome, nonoperative treatment could reasonably be considered, but if the angle was smaller than 30°, operative treatment was indicated.

Our results show that good to excellent results could be achieved in 79 % of cases, if the residual displacement observed is less than 3 mm. Surgical reduction of acetabulum fractures, however, remains a difficult procedure and should be performed by experienced surgeons under optimal conditions. Preoperative planning of the operation is vital.A close correlation was found between satisfactory radiographical and clinical results, which were 78 % and 79 % respectively. These correlations imply the necessity of a complete reduction or as near anatomic as possible if a satisfactory outcome of these fractures is to be expected.

Our postoperative complications were similar to those of other reported series of acetabular fractures.

In our view, all displaced acetabular fractures of the weight-bearing part of the dome, i.e. transtectal fractures seen within 2 weeks after injury, should be treated operatively. Later reconstruction is often more difficult and leads to less satisfactory results. Retained bone fragments in the joint that are large enough to cause incongruity or to prevent reduction of a dislocation are an absolute indication for open reduction and removal of the fragments. Associated femoral shaft and/or head fractures, primary sciatic nerve lesion and ipsilateral knee disruption are also indications for ORIF.

Conservative treatment is only justified in undisplaced fractures and in fracture types where the relationship between the femoral head and the dome is rarely disturbed, i.e., low anterior column fractures, low transverse fractures (infratectal fractures) and also in older patients with reduced general condition and osteoporotic bone, where internal fixation is difficult to achieve.

Contra-indications for surgery are: Patients with poor general physical condition due to pre-existing internal diseases or concomitant severe injuries, patients treated conservatively longer than 4- 6 weeks and patients with undisplaced or minimally displaced acetabular fractures, as seen in CT scans. The ideal condition is to operate between the second to sixth day after injury, when the pelvic bleeding has stopped spontaneously. Condylar femoral traction should be applied and anticoagulants administered to prevent major complications, until the time of the surgery. A lateral traction may be added to the distal femoral traction when the so-called medial wall of the acetabulum, attached to either the anterior or posterior column, does not reduce when the femoral head is restored to good position under the dome.

In our patients, open reduction and internal fixation allowed discharge in an average of 24 days (range: 13 to 35 days), depending on their associated injuries. This early integration into normal life is of great importance both from a psychological and economic point of view.

The acetabulum surgery is often difficult, long and has to be performed with patience. A full check-up to eliminate any pathology and a full study of the case has to be performed. Operative treatment cannot be fully justified unless the desired perfection of osteosynthesis can be achieved.