Interfragmentary motion
Dotaz
Zobrazit nápovědu
PURPOSE OF THE STUDY To compare the treatment outcome of scaphoid facture fixation with one versus two Herbert screws (HBS). MATERIAL AND METHODS 72 patients underwent open reduction internal fixation (ORIF) following acute scaphoid fracture, and were followed prospectively by one surgeon. All fractures were Herbert & Fisher classification type B, the most common fracture lines being oblique (n=38) and transverse (n=34). Fractures with similar fracture lines were randomly assigned into two groups; fractures stabilized with one HBS (n=42) and fractures stabilized with two HBS (n=30). A specific methodology was developed for placement of two HBS; in the case of transverse fractures, screws were introduced perpendicular to the fracture line, for oblique fractures the first screw was placed perpendicular to the fracture line and the second screw was placed along the longitudinal axis of the scaphoid. RESULTS Patients were followed for a total 24 months, no patients were lost to follow-up. Outcome measures included bone healing, duration to bone healing, carpal geometry, range of motion (ROM), grip strength, and the Mayo Wrist Score. Patient rated outcomes were measured using DASH. Bone healing was radiographically and clinically confirmed in 70 patients. There were two non-unions after fixation with one HBS. Radiographic angles in both groups did not differ significantly from the physiological values. The mean duration to bone union was 1.8 months for one HBS and 1.5 months for two HBS. Mean grip strength was 47 kg in the group with one HBS (16-70 kg), 94 % of the unaffected hand, and 49 kg in the group with two HBS, 97% unaffected hand. The average Visual Analog Scale (VAS) score for the group with one HBS was 2.5, while for the group with two HBS was 2.0. Both groups had excellent and good results. For the group with two HBS, they are more. (100% for those fixed with two HBS and for those fixed with one HBS = 95% excellent and good and 5% bad results). DISCUSSION A review of the literature confirms that the addition of the second screw increases the stability in the scaphoid fractures by offering added resistance to torque forces. Most authors propose the parallel placing of both screws in all cases. In our study we offer an algorithm for the placement of screws depending of the type of fracture line. For transverse fractures screws are placed parallel and perpendicular to the fracture line, for oblique fractures the first screw is placed perpendicular to the fracture line, and the second screw is placed along the longitudinal axis of the scaphoid. This algorithm covers the main laboratory requirements for maximal fracture compression depending of the fracture line. CONCLUSIONS This study of 72 patients in whom patients with similar fracture geometry were separated into two groups fixed by one HBS and fixed by two HBS. Analysis of the results demonstrate that osteosynthesis with two HBS creates greater fracture stability. The proposed algorithm for fixation of acute scaphoid fractures using two HBS is achieved by simultaneously placing the screw along the axial axis and perpendicular to the fracture line. The stability is improved by the equal distribution of the compression force on the entire fracture surface. Key words: scaphoid fractures, Herbert screw, two screws fixation.
BACKGROUND: Open reduction and internal fixation with a plate is deemed to represent the gold standard of surgical treatment for displaced intra-articular calcaneal fractures. Standard plate fixation is usually placed through an extended lateral approach with high risk for wound complications. Minimally invasive techniques might avoid wound complications but provide limited construct stability. Therefore, 2 different types of locking nails were developed to allow for minimally invasive technique with sufficient stability. The aim of this study was to quantify primary stability of minimally invasive calcaneal interlocking nail systems in comparison to a variable-angle interlocking plate. MATERIAL AND METHODS: After quantitative CT analysis, a standardized Sanders type IIB fracture model was created in 21 fresh-frozen cadavers. For osteosynthesis, 2 different interlocking nail systems (C-Nail; Medin, Nov. Město n. Moravě, Czech Republic; Calcanail; FH Orthopedics SAS; Heimsbrunn, France) as well as a polyaxial interlocking plate (Rimbus; Intercus GmbH; Rudolstadt, Germany) were used. Biomechanical testing consisted of a dynamic load sequence (preload 20 N, 1000 N up to 2500 N, stepwise increase of 100 N every 100 cycles, 0.5 mm/s) and a load to failure sequence (max. load 5000 N, 0.5 mm/s). Interfragmentary movement was detected via a 3-D optical measurement system. Boehler angle was measured after osteosynthesis and after failure occurred. RESULTS: No significant difference regarding load to failure, stiffness, Boehler angle, or interfragmentary motion was found between the different fixation systems. A significant difference was found with the dynamic failure testing sequence where 87.5% of the Calcanail implants failed in contrast to 14% of the C-Nail group (P < .01) and 66% of the Rimbus plate. The highest load to failure was observed for the C-Nail. Boehler angle showed physiologic range with all implants before and after the biomechanical tests. CONCLUSION: Both minimally invasive interlocking nail systems displayed a high primary stability that was not inferior to an interlocking plate. CLINICAL RELEVANCE: Based on our results, both interlocking nails appear to represent a viable option for treating displaced intra-articular calcaneal fractures.
- MeSH
- biomechanika MeSH
- dospělí MeSH
- kostní destičky * MeSH
- kostní hřeby * MeSH
- lidé středního věku MeSH
- lidé MeSH
- patní kost zranění chirurgie MeSH
- testování materiálů MeSH
- zatížení muskuloskeletálního systému MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
