411/ ACTA CHIRURGIAE ORTHOPAEDICAE ET TRAUMATOLOGIAE ČECHOSL., 79, 2012, p. 411–415 ORIGINAL PAPER PŮVODNÍ PRÁCE Conservative Treatment of Acetabular Both Column Fractures: Does the Concept of Secondary Congruence Work? Konzervativní léčení zlomenin obou pilířů acetabula: funguje princip sekundární kongruence? GÄNSSLEN, A. 1 , HILDEBRAND, F. 2 , KRETTEK, C. 2 1 Klinik für Unfallchirurgie, Orthopädie und Handchirurgie, Klinikum der Stadt Wolfsburg, Wolfsburg, Germany 2 Unfallchirurgische Klinik,, Medizinische Hochschule Hannover, Hannover, Germany ABSTRACT Complete separation of all bony fragments around the acetabulum in both column fractures can lead to extra-anatomi- cal orientation of these fragments around the femoral head with the potential of a “secondary congruence”. No long-term data are known in the literature. We could follow 35 patients were a both column fracture was treated non-operatively due to different reasons. Demo- graphics, fracture type, additional fracture lesions (comminution, marginal impaction), the clinical and radiological result and joint failure (severe arthrosis, FHN, esc. THR) were analyzed. The mean age was 38 years, 27 patients were male, eight female. All but four were multiply injured with a mean ISS of 22 points. 16 patients had additional pelvic ring injuries The majority of patients showed a C1-fracture of the acetabulum (anterior column multifragmentary, posterior column simple). 31 patients healed in secondary congruence (88%). Primary displacement was half (11,4 mm, 3-27 mm) compared to patients without secondary congruence (20 mm, 17-22 mm). 80% of the patients had none or only slight pain and 77% had an excellent or good functional result (Merle d'Aubigné Score). The rate of joint failure due to non-union, femoral head necrosis, posttraumatic degenerative changes or pain was relatively low with 17% after a mean of 5 years following trau- ma. In selected patients, conservative treatment of both column fractures can lead to acceptable long-term results with a high rate of secondary congruence. INTRODUCTION The aim of every treatment concept in acetabular fractures is an anatomical joint restoration which leads to best clinical and radiographical results (8, 11). Both column fractures of the acetabulum are a relati- vely common fracture type that is observed in about one fifth of cases in large cohorts (7, 18). A both column fracture is defined as an acetabular fracture where no articular fragment is in connection with the axial skele- ton (8). In a special subgroup of both column fractures of the acetabulum the concept of “secondary congruence” was introduced by Letournel. Here, complete separation of all articular acetabular bony fragments can lead to an extra-anatomical orientation around the femoral head with the possibility of healing in secondary congruen- ce. The majority of both column fractures are treated operatively (8, 11, 15, 18). But approximately one fourth of these fractures “must” be treated conservatively (8, 11, 15, 18), due to polytrauma situation, additional comorbidities, additional soft-tissue injuries or expec- ted stable fracture situation. Letournel stated acceptable results after conservative treatment of this fracture type. Despite this, biomecha- nical data on secondary congruence indicate that non- operative treatment leads to an increase of peak pressu-