[Acetabular fractures in the elderly. Outcome of open reduction and internal fixation]

[Primary joint replacement for the treatment of acetabular fractures]

Open reduction and internal fixation are the gold standard for the treatment of dislocated acetabular fractures. A primary joint replacement is only justified in isolated cases. The indications are merely non-reconstructable acetabular fractures, accompanying displaced fractures of the femoral neck and non-reconstructable fractures of the femoral head.Because of the difficulties in achieving sufficient cup stability, joint replacement for the treatment of acetabular fractures regularly requires implants designed for revision arthroplasty. The Kocher-Langenbeck approach provides the most versatile options, as it enables simultaneous stabilization of the dorsal acetabular structures, which are essential for the stability of the cup.For primary joint replacement as a treatment of acetabular fractures, survival of the prosthetic cup is markedly worse when compared to elective primary joint replacement. Particularly in younger patients but also in aged patients, every effort should be made to achieve a press fit of the cup. In most cases, this will include reduction and fixation of the fracture for stabilization of the acetabulum prior to joint replacement. A staged approach with an early secondary replacement intervention seems to provide better overall results than simultaneous fracture fixation and joint replacement.

Surgical Drill Guide for Insertion of an Infra-Acetabular Screw Based on an Anatomically Precontoured Plate System: A Cadaveric Study

PURPOSE

Due to the anatomic structure of the pelvis, free-hand placement of screws in the acetabular fracture management can be difficult. Infra-acetabular screw fixation increases acetabular stability by distal fixation of the cup. Aim of this cadaveric study is to investigate if a plate-referenced drill guide can provide save placement of an infra-acetabular screw over a precontoured suprapectineal quadrilateral buttress plate (SQBP).

METHODS

We constructed a drill guide for an infra-acetabular screw based on the surface of an anatomically precontoured SQBP. A total of 12 adult cadaveric acetabular specimens were used for drill guide-assisted placement of the infra-acetabular screw. The drill guide contains a radiopaque spiral to allow longitudinal fine adjustment of the SQBP along the pelvic brim to assure correct position of the plate-drill-guide construct in relation to the Koehler's teardrop. After screw placement, we conducted a computed tomography (CT) scan of all specimens to assess the actual position of the screw in relation of the infra-acetabular corridor and the acetabular joint surface.

RESULTS

The position of the screw was within the infra-acetabular corridor in all cases. We did not see any intra-articular or intrapelvic screw penetration. The mean distance of the centerline of the screw to the medial border of the infra-acetabular corridor was 3.35 mm. The secure distance to the virtual surface of the femoral head to was 7.3 mm.

CONCLUSIONS

A plate-referenced drill guide can provide safe placement of an infra-acetabular screw for treatment of acetabular fractures. Radiographic fine adjustment is necessary to access the optimal entry point.

CT-scan based anatomical study as a guidance for infra-acetabular screw placement

Background

The infra-acetabular corridor is quite narrow, which makes a challenge for the orthopedists to insert the screw. This study aimed to explore the relationship between the infra-acetabular corridor diameter (IACD) and the minimum thickness of medial acetabular wall (MTMAW), and to clarify the way of screw placement.

Methods

The Computed tomography (CT) data of 100 normal adult pelvises (50 males and 50 females respectively) were collected and pelvis three-dimensional (3D) reconstruction was performed by using Mimics software and the 3D model was imported into Geomagic Studio software. The perspective of acetabulum was carried out orienting from iliopubic eminence to ischial tuberosity and the IACD was measured by placing virtual screws which was vertical to the corridor transverse section of “teardrop”. The relationship between IACD and MTMAW was analyzed. When IACD was ≥5 mm, 3.5 mm all-in screws were placed. When IACD was < 5 mm, 3.5 mm in-out-in screws were placed.

Results

The IACD of males and females were (6.15 ± 1.24) mm and (5.42 ± 1.01) mm and the MTMAW in males and females were (4.40 ± 1.23) mm and (3.60 ± 0.81) mm respectively. The IACD and MTMAW in males were significantly wider than those of females (P < 0.05), and IACD was positively correlated with MTMAW (r = 0.859), the regression equation was IACD = 2.111 + 0.917 MTMAW. In the all-in screw group, 38 cases (76%) were males and 33 cases (66%) were females respectively. The entry point was located at posteromedial of the apex of iliopubic eminence, and the posterior distance and medial distance were (8.03 ± 2.01) mm and (8.49 ± 2.68) mm respectively in males. As for females, those were (8.68 ± 2.35) mm and (8.87 ± 2.79) mm respectively. In the in-out-in screw group, 12 cases (24%) were males and 17 cases (34%) were females, respectively. The posterior distance and medial distance between the entry point and the apex of iliopubic eminence were (10.49 ± 2.58) mm and (6.17 ± 1.84) mm respectively in males. As for females, those were (10.10 ± 2.63) mm and (6.63 ± 1.49) mm respectively. The angle between the infra-acetabular screw and the sagittal plane was medial inclination (0.42 ± 6.49) °in males, lateral inclination (8.09 ± 6.33) °in females, and the angle between the infra-acetabular screw and the coronal plane was posterior inclination (54.06 ± 7.37) °.

Conclusions

The placement mode of the infra-acetabular screw (IAS) can be determined preoperatively by measuring the MTMAW in the CT axial layers. Compared with all-in screw, the in-out-in screw entry point was around 2 mm outwards and backwards, and closer to true pelvic rim.

Infra-acetabular screw exited between ischial tuberosity and ischial spine is more suitable for Asian population: a 3D morphometric study

Background

Recently, the infra-acetabular screw has been proposed for use in treatment of acetabular fractures as a part of a periacetabular fixation frame. Biomechanical studies have shown that an additional infra-acetabular screw placement can enhance the fixation strength of acetabular fracture internal fixation. Currently, the reported exit point of the infra-acetabular screw has been located at the ischial tuberosity (Screw I). However, our significant experience in placement of the infra-acetabular screw has suggested that when the exit point is located between the ischial tuberosity and the ischial spine (Screw II), the placement of a 3.5 mm infra-acetabular screw may be easier for some patients. We conducted this study in order to determine the anatomical differences between the two different IACs.

Methods

The raw datasets were reconstructed into 3D models using the software MIMICS. Then, the models, in the STL format model, were imported into the software Geomagic Studio to delete the inner triangular patches. Additionally, the STL format image processed by Geomagic Studio was imported again into MIMICS. Finally, we used an axial perspective based on 3D models in order to study the anatomical parameters of the two infra-acetabular screw corridors with different exit points. Hence, we placed the largest diameter virtual screw in the two different screw corridors. The data obtained from this study presents the maximum diameter, length, direction, and distances between the entry point and center of IPE.

Results

In 65.31% males and 40.54% females, we found a screw I corridor with a diameter of at least 5 mm, while a screw II corridor was present in 77.55% in males and 62.16% in females. Compared to screw I, the length of screw II is reduced, the angle with the coronal plane is significantly reduced, and the angle with the transverse plane is significantly increased.

Conclusions

For East Asians, changing the exit point of the infra-acetabular screw can increase the scope of infra-acetabular screw use, especially for females.

Geriatric Acetabular Surgery: Letournel's Contraindications Then and Now-Data From the German Pelvic Registry

OBJECTIVE

In his original series of 129 surgically treated acetabular fractures, Letournel did not operate on patients older than 60 years. Almost 30 years later, he still emphasized that no patients with reduced bone quality should be operated on. The aim of the study was to analyze epidemiologic characteristics and treatment modes for today's cohort of elderly patients with acetabular fractures.

DESIGN

Retrospective analysis.

SETTING

Multicenter registry/Level I trauma center.

PATIENTS

Three thousand seven hundred ninety-three patients who had sustained a fracture of the acetabulum.

INTERVENTION

Operative and nonoperative treatment of acetabular fractures.

MAIN OUTCOME MEASUREMENTS

Epidemiologic characteristics, treatment mode, in-hospital mortality, rate of secondary hip arthroplasty, and quality of life indicated by EQ-5D score.

RESULTS

For the multicenter registry, more than 50% of all patients with acetabular fractures had an age of 60 years or over. The age peak was found at 75-80 years. Fifty percent of the elderly patients were treated surgically. The in-hospital mortality was significantly higher in elderly patients than patients younger than 60 years. In our Level I trauma center, surgical treatment by open reduction and internal fixation did not influence in-hospital mortality or quality of life of elderly patients with acetabular fractures.

CONCLUSIONS

Today, elderly persons represent the dominant cohort among patients with fractures of the acetabulum. Fifty-five years after the publication of Letournel's original case series, data indicate that currently, surgical treatment is a common and necessary option in the therapy of acetabular fractures in elderly patients.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

A guideline for placement of an infra-acetabular screw based on anatomic landmarks via an intra-pelvic approach

BACKGROUND

Due to demographic changes, more and more fracture patterns involving anterior acetabular structures occur. The infra-acetabular screw is seen a useful tool to increase stability in fixation of the acetabular cup. However, the exact position of this screw in relation to anatomic landmarks which are intra-operatively palpable via an intra-pelvic approach has not yet been determined.

METHODS

This biomorphometric experimental study references the ideal screw position of an infra-acetabular screw to anatomic landmarks palpable via an intra-pelvic approach. Therefore, we created a computer tomography-based 3D-model of 40 patients (20 women, 20 men) who received a computer tomography (CT) scan of the pelvis for any other reason than an acetabular fracture.

RESULTS

The entry point of an ideal infra-acetabular was of high constancy. At mean, this point was 10.2 mm caudal and 10.4 mm medial of the ilio-pubic/ilio-pectineal eminence. This reference is independent of age, gender, or physical dimensions. However, we found gender-dependent differences for the angulation and the length of the screw.

CONCLUSIONS

This study provides a comprehensive guideline to determine the ideal entry point for an infra-acetabular screw via an intra-pelvic approach. The entry point is located 10.2 mm caudal and 10.4 mm medial of the ilio-pubic/ilio-pectineal eminence.

TRIAL REGISTRATION

Clinical Trial Registry University of Regensburg Z-2017-0930-1 . Registered 04. Dec 2017.