PURPOSE OF THE STUDY Vertically unstable transforaminal sacral fractures can be stabilized with several types of transiliac internal fixators (TIFI): the classical one (TIFI-C), the supraacetabular one (TIFI-A) and by dual application of TIFI (DTIFI). MATERIAL AND METHODS Pelvic models made of solid foam (Sawbones 1301) were used in the study. Mechanical loading tests were performed in order to assess the stiffness of the studied pelvic structures. The stiffness of the intact model was approximated as the slope of load/displacement curve. Then vertically unstable right-sided linear transforaminal fracture was created and subsequently fixed by TIFI-C, TIFI-A and DTIFI (each fixator for a separate model). The fixation techniques were compared based on the ratio between the stiffness of the treated and of the intact pelvis. Motion of the posterior pelvic structures and their deformations were measured using a photogrammetric system with four synchronous cameras. Loads applied at the base of sacrum and sacral base displacements were recorded by the testing device and used to assess the stiffness of the model structure. A dedicated load cell and a monoaxial extensometer were utilised. Every measurement was repeated at least 10 times. Obtained data were analysed by one way ANOVA test with post hoc comparison by Tukey HSD test. RESULTS Mean stiffness ratio (±1SD) of pelvic structure was 0.638 ± 0.005 for TIFI-C, 0.722 ± 0.014 for TIFI-A and 0.720 ± 0.008 for DTIFI. Dual transiliac internal fixation and supraacetabular fixation were superior to the classical one (p < 0.0001), but DTIFI and TIFI-A stiffness ratios were statistically equivalent (p = 0.9112). CONCLUSIONS Results of the mechanical analysis using pelvic models indicate that for linear vertical transforaminal sacral fracture without comminuted zone, an application of either TIFI-A or DTIFI provides significantly higher stiffness of the lateral pelvic segment than application of TIFI-C. Key words: transforaminal sacral fracture, transiliac internal fixator, dual TIFI, stability, biomechanics, digital image correlation.
- MeSH
- biomechanika MeSH
- fraktury kostí * MeSH
- interní fixátory MeSH
- kostní šrouby MeSH
- křížová kost chirurgie MeSH
- lidé MeSH
- mechanické testy MeSH
- pánev MeSH
- pánevní kosti * diagnostické zobrazování chirurgie MeSH
- vnitřní fixace fraktury MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
This paper presents the development of a new framework for stump-socket interface force estimation for future prosthesis optimization in transfemoral amputees. It combines experimental data and modelling, including gait analysis, subject-specific simulation of gait and finite element modelling of the residual limb at the prosthesis interaction point. These case-study preliminary results demonstrate how reaction forces between the residual limb and prosthesis can be estimated and used as input data for detailed finite element analysis based on medical images. Gait simulation may provide useful insight in subject-specific musculoskeletal modelling while finite element simulation may provide in-silico feedback for prosthesis optimization with respect to various daily activities.
- Publikační typ
- abstrakt z konference MeSH
- MeSH
- interní fixátory využití MeSH
- kostní šrouby MeSH
- lidé MeSH
- odstranění implantátu MeSH
- ortopedické fixační pomůcky využití MeSH
- pánevní kosti * chirurgie zranění MeSH
- sakrokokcygeální krajina chirurgie zranění MeSH
- vnitřní fixace fraktury MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
1st edition 541 stran : ilustrace (převážně barevné), portréty, tabulky ; 24 cm
- Konspekt
- Ortopedie. Chirurgie. Oftalmologie
- NLK Obory
- chirurgie
- experimentální medicína
- NLK Publikační typ
- kolektivní monografie
PURPOSE OF THE STUDY: A comparison of radiological and clinical results between dorsal pelvic segment stabilization with a transiliac internal fixator (TIFI) and that with two iliosacral screws (IS). MATERIAL AND METHODS: In this prospective study, both the TIFI and the IS group had 32 patients. The majority of injuries were assessed as type C1.3 because only patients with a high-energy mechanism of injury were included. Radiological results were evaluated according to the Matta scoring system and clinical outcome using the Majeed score and the Pelvic Outcome Score. Categorical data were evaluated by the two-sided Fisher's exact test or Pearson's χ2 test and continuous data by Student's t-test. A test result with p<0.05 was considered statistically significant. RESULTS: In the TIFI group, the mean posterior displacement was 2.2 mm, in the IS group it was 1.9 mm (p=0.58542). The pelvic outcome scores in the TIFI group were: excellent, 28%; good, 12%; fair, 48.0%; and poor, 4 %; in the IS group they were: excellent, 11.1%; good, 22.2%; fair, 66.7%; and poor, 0.0% (p=0.51731). The Majeed scores were as follows: excellent, 56.0%; good, 16.0%; fair, 20.0%; poor 8.0 % for the TIFI group and excellent, 50.0%; good, 27.8%; fair, 11.1%; and poor, 11.1% for the IS group (p=0.70187). Within the total, average Majeed score was 80.64 points in TIFI, 80.67 in IS (p=0.99654). In a sub-analysis of unilateral transforaminal fractures (Pohlemann type II), the average score for TIFI was 82.8 points and only 53.5 points for IS; the differences were statistically significant (p=0.04517). No intraoperative complications were associated with TIFI and one injury to the superior gluteal artery (3.1%) and two iatrogenic neurological injuries with IS (6.3%; p=0.23810). In the TIFI group, the fixator was removed without complications. In the IS group, post-operative wound bleeding following screw removal occurred in three patients (20.0%; p=0.22414), complete extraction of screws and washers was successful only in seven patients (46.7%), washers were left in situ in six patients (40.0 %) and IS removal was not possible in two patients (13.3%). The difference in complications between the groups was highly significant (p=0.00220). DISCUSSION: The results of our study are in agreement with those of the relevant studies published recently as well as with the outcomes of transiliac plate fixation reported in the literature. TIFI implantation is preferred in transforaminal and central sacral fractures because, unlike iliosacral screws, it carries a low risk of excessive compression of the sacral foramina and iatrogenic neurological injury. There were no significant differences in clinical and radiological findings between TIFI and IS procedures. Only in unilateral transforaminal fracture the TIFI stabilization had better outcome, as shown by the Majeed score. The IS fixation was associated with a higher rate of complications not only in primary implantation, but also at implant removal. CONCLUSIONS: The TIFI technique is superior to the IS procedure in fixation of unilateral transforaminal fractures and provides a reasonable alternative to the existing types of minimally invasive fixation.
- MeSH
- fraktury kostí radiografie chirurgie MeSH
- interní fixátory * MeSH
- kostní šrouby * MeSH
- lidé MeSH
- miniinvazivní chirurgické výkony přístrojové vybavení metody MeSH
- os ilium chirurgie MeSH
- pánevní kosti zranění radiografie chirurgie MeSH
- prospektivní studie MeSH
- vnitřní fixace fraktury přístrojové vybavení metody MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- anglický abstrakt MeSH
- časopisecké články MeSH
- hodnotící studie MeSH
- srovnávací studie MeSH
PURPOSE: Vertically unstable sacral transforaminal fractures can be stabilized with a transiliac internal fixator (TIFI) or two iliosacral screws (IS). This study was designed to compare stiffness between TIFI and IS. METHODS: Using CT images finite element model of the pelvis was developed. Denis II type fracture was simulated and fixed either with TIFI or two IS. The sacral base was loaded vertically (250-500 N), displacement magnitudes on medial and lateral fracture surface and the maximum bone stress were calculated. The intact pelvis was used as a reference. Stiffness was determined by linear regression of load and displacement, computed stiffness ratio %. The von Mises stress was expressed as % ratio, evaluation of colour mapping was made. RESULTS: The mean stiffness ratio medially in TIFI was 75.22%, in IS 46.54% (p = 0.00005), laterally in TIFI 57.88%, in IS 44.74% ( p = 0.03996). The von Mises stress ratio of TIFI was 139.27%, of IS 565.35% ( p < 0.00001). CONCLUSIONS: Significantly higher stiffness and lower stress were found in TIFI model. TIFI provides a lower risk of over-compression of the fracture line in comparison with IS. TIFI thus exhibits superiority for fixation of trans- foraminal fractures, particularly with comminutive zone.
- MeSH
- analýza metodou konečných prvků MeSH
- biomechanika MeSH
- dopravní nehody MeSH
- fraktury kostí chirurgie MeSH
- fraktury páteře chirurgie MeSH
- interní fixátory * MeSH
- kostní šrouby * MeSH
- křížová kost chirurgie MeSH
- lidé MeSH
- lineární modely MeSH
- os ilium chirurgie MeSH
- pevnost v tlaku MeSH
- počítačová rentgenová tomografie MeSH
- regresní analýza MeSH
- statistické modely MeSH
- testování materiálů MeSH
- vnitřní fixace fraktury přístrojové vybavení metody MeSH
- zobrazování trojrozměrné MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
PURPOSE OF THE STUDY The aim of the study was to find out whether the frequency and intensity of patellar pain can be affected by individual rotational alignment of the femoral component in total knee arthroplasty, as compared with the standard 3 degrees of external femoral rotation in conventional procedures. MATERIAL AND METHODS In randomly selected patients treated for knee osteoarthritis by total joint replacement between January 2007 and January 2011, the occurrence of patellar pain was assessed. The evaluated knees were allocated to two groups. Group 1 included 350 knee joints with conventional femoral rotational alignment, i.e., 3 degrees of external rotation. Group 2 comprised 380 knee joints with an individual rotational alignment of the femoral component based on the condylar twist angle. Post-operative anterior knee pain was assessed on the following scale: 1, no pain; 2, occasional mild pain; 3, moderate pain; 4, severe pain. RESULTS In group 1, 312 knee joints were free from pain, 15 occasionally experienced mild pain, 15 had moderate and eight had severe pain. A total of 23 revision operations were performed for patellar pain at the anterior knee and pain around the patella refractory to non-steroidal anti-rheumatic and rehabilitation therapy. In group 2, there were 331 pain-free knees, 48 with occasional mild pain, one with moderate pain and no knee with severe pain. No revision surgery was required. One patient with moderate patellar pain underwent surgery for spinal canal stenosis; after that knee pain was only mild. The groups were compared, as to pain assessment results, using the test of equality of relative frequencies, i.e., score categories 1+2 versus 3+4 of 350 (group 1) equalled 23 (6.57%) were compared with 1 (0.26%) of 380 (group 2); the difference was significant (p < 0.001). Using the same test for comparison of the frequency of repeat operations, i.e., 23 (0.57%) of 350 (group 1) versus 0 (0%) of 380 (group 2), also gave a significant result (p = 0.001). DISCUSSION Mild and occasional pain was recorded in both groups, suggesting that femoral component malrotation is not the only cause of patellar pain following total knee arthroplasty. A markedly lower incidence of moderate and severe pain and no need for revision surgery found in group 2 provides evidence that the use of individual rotational alignment of the femoral component is fully justified. CONCLUSIONS An individual rotational alignment of the femoral component can significantly reduce the incidence of moderate to severe patellar pain or even need for revision surgery.
- MeSH
- lidé středního věku MeSH
- lidé MeSH
- patela patofyziologie MeSH
- pooperační bolest * etiologie prevence a kontrola MeSH
- rotace MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- totální endoprotéza kolene * klasifikace metody MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
- srovnávací studie MeSH
