Primary stability of multi-hole cups compared to plate osteosynthesis in osteoporotic anterior column and posterior hemi-transverse acetabular fractures—A biomechanical comparison
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ABSTRACT: Introduction
Acetabular fractures pose high demands on the surgeon and in the case of osteosynthetic treatment, anatomical reconstruction has the highest priority to achieve a good outcome. However, especially in older patients with poor bone quality, even anatomical reconstruction is no guarantee for a good clinical outcome and may nevertheless end in early osteoarthritis. Primary arthroplasty therefore has an increasing importance in the treatment of these patients. The aim of this study was to biomechanically compare fracture gap displacement and failure load as an assessment measure of the primary stability of conventional plate osteosynthesis with the treatment using a sole multi-hole cup for acetabular fractures. Methods
Six hemi-pelvises each with anterior column and posterior hemi-transverse (ACPHT) fracture were treated with either plate osteosynthesis or a multi-hole cup. The tests were carried out in a standardised test set-up with cyclic loading in various stages between 150 N and 2500 N. The fracture gap displacement was recorded with optical 3D measuring and the failure load was determined after the cyclic measurement. Results
With increasing force, the fracture gap displacement increased in both procedures. In each group there was one treatment which failed at the cyclic loading test and a bone fragment was broken out. The primary stability in arthroplasty was comparable to that of the standard osteosynthesis. Conclusions
The results found seem promising that the primary arthroplasty with a sole multi-hole cup and corresponding screw fixation achieves an initial stability comparable to osteosynthesis for typical ACPHT fractures. However, further clinical studies are needed to prove that the cups heal solidly into the bone.
SUBMITTER: Hoch A
PROVIDER: S-EPMC9328528 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:OBJECTIVE:The purpose of this study was to compare the stability and feasibility of four fixation constructs in a posterior column acetabular fracture: one reconstruction plate, one reconstruction plate and lag screw, two reconstruction plates, and a W-shaped acetabular angular plate. METHODS:Twenty embalmed cadaveric pelvises with a posterior column acetabular fractures were allocated to one of four groups: 1) a reconstruction plate, 2) a reconstruction plate with a posterior column lag screw, 3) double reconstruction plates, and 4) a W-shaped acetabular angular plate. These constructs were mechanically loaded on a testing machine, and construct stiffness values were measured. Strain gauges were utilized to measure the mechanical behavior in the condition of compressive force. RESULTS:Final stiffness was not different between the two reconstruction plates (445.81±98.30 N/mm) and the W-shaped acetabular angular plate (447.43±98.45 N/mm, p = 0.524), both of which were superior to a single reconstruction plate (248.90±61.95 N/mm) and a combined plate and lag screw (326.41±94.34 N/mm). Following the fixation of the W-shaped acetabular angular plate, the strain distribution was similar to the intact condition around the acetabulum. The parameters of the W-shaped acetabular angular plate that were observed at the superior region of the acetabulum were less than those of a single reconstruction plate (p<0.05), a single reconstruction plate with lag screw (p<0.05), and two reconstruction plates (p<0.05). CONCLUSIONS:The novel W-shaped acetabular angular plate fixation technique was able to provide the biomechanically stiffest construct for stabilization of a posterior column acetabular fracture; it also resulted in a partial restoration of joint loading parameters toward the intact state.
| S-EPMC5695793 | biostudies-literature
Project description:BACKGROUND:Treating proximal humerus fractures can be challenging because of large metaphyseal defects that conceal anatomical landmarks. In such cases, medial cortical support with, for example, calcar screws, is mandatory. Nevertheless, varus dislocations and implant failures in patients with impaired bone quality persist. Thus, the need for effective treatment of these patients exists. Hybrid double plate osteosynthesis was introduced as an alternative, yielding similar results as calcar screws. However, a biomechanical comparison of the stability of these two techniques is pending. METHODS:Cadaveric humeral specimens were treated with plate osteosynthesis and calcar screws (group 1, n = 9) or hybrid double plate osteosynthesis (group 2, n = 9) using a proximal humerus fracture model with a two-part fracture. Displacement, stiffness, failure mode, and ultimate load were examined biomechanically in a cyclic compressive-loading scenario. RESULTS:Although the hybrid double plate osteosynthesis (group 2) tended to confer higher stiffnesses than the medial support screws at higher cycles (group 1), this trend was below the level of significance. The displacement revealed non-significantly lower values for group 1 as compared with group 2 for cycles 50 and 2000, but at 5000 cycles, group 2 offered non-significantly lower displacement values than group 1. The ultimate load tended to be non-significantly higher in the hybrid double plate osteosynthesis group (group 2: 1342±369 N, group 1: 855±408 N). Both groups yielded similar failure rates, with the majority of failures in group 2 being gap closures (n = 8), whereas those in group 1 being plate dislocations (n = 4). CONCLUSIONS:The use of an additive plate osteosynthesis in the region of the bicipital groove may be a potential alternative to the previously-established method of using calcar screws. The biomechanical data obtained in this study suggests that hybrid double plate osteosynthesis is as rigid and robust as calcar screws.
| S-EPMC6205804 | biostudies-literature
Project description:Hydroxyapatite (HA) coating is believed to improve bone-implant ingrowth and long-term survival of prostheses. Recent studies, however, have challenged this view. Furthermore, HA particles may produce third-body wear and initiate aseptic loosening of implants. We report the performance of HA- and porous-coated acetabular cups in a prospective randomized trial.This was an 8-year follow-up study of our previously published prospective randomized study to compare clinical outcomes, survival, periprosthetic bone mineral density, migration, and wear rates of HA- and porous-coated acetabular cups. Dual X-ray absorptiometry (DXA) and Ein Bild Roentgen Analyse (EBRA) measurements were used. 100 patients who underwent unilateral cementless total hip arthroplasty were randomized to either porous-coated cups or HA-coated cups. Patients were examined preoperatively and at 3, 6, and 9 months, and also 1, 3, and 8 years after surgery. 81 patients were available for 8-year follow-up, 40 with porous-coated cups and 41 with HA-coated cups.Age, sex, bone mineral density, and clinical results (Harris hip score) were similar in the 2 groups. The survival, wear, and migration patterns of the cups were also similar in both groups. The results of periprosthetic bone mineral density scans in region of interest 2 was in favor of the porous-coated cups, but there were no differences between the 2 groups in all the remaining regions of interest.HA coating had no statistically significant effect on clinical results, survival, wear, or migration at the 8-year follow-up.
| S-EPMC3851667 | biostudies-literature
Project description:BACKGROUND:Geriatric acetabular fractures require fixation with sufficient primary stability to allow for immediate full-weight bearing. Minimally-invasive procedures would be desirable in order to keep perioperative morbidity low. The purpose of this study was to compare the biomechanical strength of lag screw-only fixation of anterior column posterior hemi-transverse (ACPHT) acetabular fractures to standard anatomical plate fixation. METHODS:Standardized ACPHT fractures were created in fourth generation synthetic pelvis models and stabilized by either an anatomical buttress plate (n?=?4) or by a screw-only construct (n?=?4). In a validated setup, a cyclic loading protocol was applied with increasing axial force (3200?cycles, 175?N to 2250?N). Construct survival, acetabular fracture motion, and mode of failure were assessed. RESULTS:The median number of cycles needed until failure of the construct occurred was 2304?cycles (range, 2020 to 2675) in the plate fixation group and 3200?cycles (range, 3101 to 3200) for the screw fixation constructs (p?=?.003). With regard to energy absorbed until failure, the plate fixation group resisted to 1.57?×?106?N*cycles (range, 1.21?×?106 to 2.14?×?106) and the screw fixation group to 3.17?×?106?N*cycles (range, 2.92?×?106 to 3.17?×?106; p?=?.001). All plate fixation specimens failed with a break-out of the posterior-column screw in the quadrilateral wing of the anatomical plate within a maximum load of 1750?N while the screw fixation constructs all survived loading of at least 2100?N. Acetabular fracture gap motion, acetabular rim angle, and medial femoral head subluxation as measures of fracture displacement were all not different between the two groups (p?>?0.1). CONCLUSIONS:In this in vitro biomechanical study, screw-only fixation of an ACPHT acetabular fracture resulted in at least as good construct survival as seen for standard buttress plate fixation. Both methods resisted sufficiently to forces that would be expected under physiologic conditions.
| S-EPMC6346571 | biostudies-literature
Project description:Nonsurgical treatment of Jefferson burst fractures (JBF) confers increased rates of C1-2 malunion with potential for cranial settling and neurologic sequels. Hence, fusion C1-2 was recognized as the superior treatment for displaced JBF, but sacrifies C1-2 motion. Ruf et al. introduced the C1-ring osteosynthesis (C1-RO). First results were favorable, but C1-RO was not without criticism due to the lack of clinical and biomechanical data serving evidence that C1-RO is safe in displaced JBF with proven rupture of the transverse atlantal ligament (TAL). Therefore, our objectives were to perform a biomechanical analysis of C1-RO for the treatment of displaced Jefferson burst fractures (JBF) with incompetency of the TAL. Five specimens C0-2 were subjected to loading with posteroanterior force transmission in an electromechanical testing machine (ETM). With the TAL left intact, loads were applied posteriorly via the C1-RO ramping from 10 to 100 N. Atlantoaxial subluxation was measured radiographically in terms of the anterior antlantodental interval (AADI) with an image intensifier placed surrounding the ETM. Load-displacement data were also recorded by the ETM. After testing the TAL-intact state, the atlas was osteotomized yielding for a JBF, the TAL and left lateral joint capsule were cut and the C1-RO was accomplished. The C1-RO was subjected to cyclic loading, ramping from 20 to 100 N to simulate post-surgery in vivo loading. Afterwards incremental loading (10-100 N) was repeated with subsequent increase in loads until failure occurred. Small differences (1-1.5 mm) existed between the radiographic AADI under incremental loading (10-100 N) with the TAL-intact as compared to the TAL-disrupted state. Significant differences existed for the beginning of loading (10 N, P = 0.02). Under physiological loads, the increase in the AADI within the incremental steps (10-100 N) was not significantly different between TAL-disrupted and TAL-intact state. Analysis of failure load (FL) testing showed no significant differences among the radiologically assessed displacement data (AADI) and that of the ETM (P = 0.5). FL was Ø297.5 +/- 108.5 N (range 158.8-449.0 N). The related displacement assessed by the ETM was Ø5.8 +/- 2.8 mm (range 2.3-7.9). All specimens succeeded a FL >150 N, four of them >250 N and three of them >300 N. In the TAL-disrupted state loads up to 100 N were transferred to C1, but the radiographic AADI did not exceed 5 mm in any specimen. In conclusion, reconstruction after displaced JBF with TAL and one capsule disrupted using a C1-RO involves imparting an axial tensile force to lift C0 into proper alignment to the C1-2 complex. Simultaneous compressive forces on the C1-lateral masses and occipital condyles allow for the recreation of the functional C0-2 ligamentous tension band and height. We demonstrated that under physiological loads, the C1-RO restores sufficient stability at C1-2 preventing significant translation. C1-RO might be a valid alternative for the treatment of displaced JBF in comparison to fusion of C1-2.
| S-EPMC2989204 | biostudies-literature
Project description:BackgroundThe aim of this study was to investigate the applicable safety and biomechanical stability of iliosacral triangular osteosynthesis (ITO) through 3D modeling and finite element (FE) analysis.MethodsPelvic CT imaging data from 100 cases were imported into Mimics software for the construction of 3D pelvic models. The S2-alar-iliac (S2AI) screws and S2 sacroiliac screws were placed in the S2 segment with optimal distribution and their compatibility rate on the S2 safe channel was observed and analyzed. In the FE model, the posterior pelvic ring was fixed with two transsacral screws (TTS), triangular osteosynthesis (TO) and ITO, respectively. Four different loading methods were implemented in sequence to simulate the force in standing, flexion, right bending, and left twisting, respectively. The relative displacement and change in relative displacement of the three fixing methods were recorded and analyzed.ResultsThe theoretical compatibility rate of S2AI screw and S2 sacroiliac screw in S2 segment was 94%, of which 100% were in males and 88% in females. In the FE model, in terms of overall relative displacement, TTS group showed the smallest relative displacement, the ITO group showed the second smallest, and the TO group the largest relative displacement. The change in relative displacement of the TTS group displayed the smaller fluctuations in motion. The change in relative displacement of the TO group under right bending and left twisting displayed larger fluctuations, while the ITO group under flexion displayed larger fluctuations.ConclusionsThe simultaneous placement of S2AI screw and S2 sacroiliac screw in the S2 segment is theoretically safe. Although the biomechanical stability of ITO is slightly lower than TTS, it is better than TO, and can be used as a new method for the treatment of posterior pelvic ring injuries.
| S-EPMC8609831 | biostudies-literature
Project description:BackgroundUncemented press-fit acetabular cups without screws rely on the elastic recoil of the bone for its primary stability and tend to leave polar gaps with its use. The clinical significance of these gaps and the functional outcome of the patients with polar gaps is evaluated in this study.MethodsThis comparative analysis was done on 224 cementless primary THA using Deltamotion® Hip System from January 2010 to December 2017. Patients were divided into two groups based on the presence or absence of polar gaps on immediate post-operative radiographs. Patients were observed for their clinical, radiological and functional outcomes with regular follow ups. At each follow-up, patients' clinical outcome was evaluated using the Harris Hip Score (HHS) and Patient Reported Outcome Measures (PROMs).Results14 of 224 patients(6.25%) demonstrated polar gaps in their immediate post-operative radiographs. No statistically significant difference was noted in the final mean HHS between the two groups. The polar gaps ranged from 0.5 to 1.8?mm (mean-1.09?mm). None of the patients showed progression of the polar gaps. All patients showed bony ingrowth into the gaps at a mean of 8.57 months.ConclusionThe presence of polar gaps in the immediate post-operative radiographs are not of a major clinical significance provided a secure peripheral fit is achieved intra-operatively. The functional outcome and rehabilitation in such patients is at par with that seen in the patients without polar gaps. Disappearance of these polar gaps is a rule rather than an exception.
| S-EPMC6985010 | biostudies-literature
Project description:UNLABELLED: In vitro studies demonstrating excessive wear in polyethylene cups sterilized using gamma irradiation and stored in air led to the abandonment of this sterilization technique. We evaluated the clinical wear performance of a metal femoral component on a polyethylene cup in a hip prosthesis from a selected subset of implants in a group of patients followed for at least 20 years and assessed the time dependency of variation in penetration rates. We measured penetration in 33 polyethylene cups in 25 patients who had a Charnley low-friction arthroplasty between 1982 and 1984. All patients had Charnley Ogee cups implanted for more than 20 years and sterilized using the gamma irradiation in air technique. If degradation occurred over time in vivo, it was not reflected by an increased penetration rate with increasing time in vivo; even after 20 years of implantation, the degree of wear remained low. This suggests gamma irradiation affects wear on ultra-high-molecular-weight polyethylene by reducing wear secondary to the crosslinking, by increasing wear as shown through in vitro studies of heavily oxidized samples, or by oxidation resulting from prolonged shelf life. The effect of progressive oxidation in vivo does not appear to affect wear in vivo. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
| S-EPMC2505130 | biostudies-other
Project description:IntroductionStable reduction and rigid fixation of the sacrum and posterior ring structures are of paramount importance in the management of complex pelvic ring disruptions, Tile B and C. The major concern with the use of conventional methods, like iliosacral screws and iliolumbar fixations is the increased risk for surgical and implant-related morbidity, especially in difficult situations, such as comminuted, bilateral sacral fractures, and fractures in the dysmorphic sacrum. Although various biomechanical studies have reported the posterior trans-iliac plates to provide maximum resistance to distracting forces by the principle of tension band, the literature pertaining to this implication in clinical studies has been limited. The purpose of our study was to assess the efficacy of the trans-iliac plate in the management of unstable sacral fractures and its utility in pelvic disruptions associated with surgical site morbidity.MethodologyThe patients with unstable pelvic fractures (Tile B and C) between 2013 and 2017 were retrospectively analyzed at a trauma center. First, the anterior ring disruptions were stabilized, and then, the sacral fractures (Denis Zone 1-3) treated by posterior tension band plate osteosynthesis (3.5 mm reconstruction plate) were included. Demographic and perioperative data were assessed. The outcome variables studied were surgical morbidity, pain, loss of reduction, and union and implant-related complications. The outcomes were graded using Lindhal's (radiological) and Majeed (functional assessment) scores.ResultsThirteen patients (nine male/four female) with a median age of 42 years, had sacral fractures in Denis zones 1/2/3 (four/ten/one, respectively), resulting from Tile pelvic injury B and C were included. The pelvis in five patients was stabilized only with the posterior plate due to the anteriorly-associated surgical site morbidity (Morel-Lavallee lesions and urinary tract injuries). The mean follow-up was 21.5 ± 2.8 months. All fractures had a radiological union by 22 weeks; Lindhal's grade A in ten patients and grade B in three patients. Two out of three patients recovered from preoperative neurological involvement. Two had complained of implant prominence (BMI<19 kg/m2) and there were no implant failures. Four had excellent, six had good, and three had fair or poor functional outcomes.ConclusionThe posterior trans-iliac plate is a minimally invasive and safe procedure that can be used in a wide range of unstable sacral fractures with notably less implant failure rate. The rigid posterior construct restores the principle tension between the iliac blades and minimizes the secondary displacement of the anterior disrupted structures, thereby useful in managing ring disruptions with surgical site morbidity.
| S-EPMC6823733 | biostudies-literature
Project description:BackgroundTransverse acetabular ligament (TAL) is a 3-dimensional structure which cannot be defined by a single plane. Therefore, we aimed at describing the orientation of different parts of TAL with respect to anterior pelvic plane (APP) and correlate it with gender, body mass index (BMI), and Lewinnek's safe zone.MethodsA total of 109 consecutive patients undergoing imageless navigated THA were prospectively studied. Computer navigation was used as the measurement tool. APP was registered for navigation. After excision of osteophytes, a trial component matching the size of unreamed acetabular cavity was aligned with acetabular rim, outer and inner margins, and middle of TAL to record cup orientation with computer tracker.ResultsNinety-nine patients (41 males and 58 females, mean BMI of 28.8kg/m2) were studied after applying exclusion criteria. Mean acetabular inclination was 55.15°, 53.00°, 47.70°, and 42.60° respectively, for acetabular rim, outer, middle, and inner margins of the TAL. Corresponding mean acetabular anteversion was 6.63°, 7.41°, 11.23° and 14.90°respectively. Overall, 17.17%, 28.28%, 47.47% and 71.71% of cup orientation corresponding to acetabular rim, outer, middle, and inner margin of TAL respectively, were within Lewinnek's safe zone. No association was established between BMI and acetabular orientation. Males had overall lesser anteversion than females.ConclusionWe describe orientation of outer, middle, and inner margins of TAL, as reference planes for TAL, in relation to APP. The anteversion differs significantly with gender. A knowledge about these will assist surgeon in component placement during THA, with inner margin of TAL providing the best chance of orientation out of the studied landmarks.
| S-EPMC7818603 | biostudies-literature