RSL Fusion with Excision of Distal Scaphoid and Triquetrum: A Cadaveric Study.
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ABSTRACT:
SUBMITTER: Bain GI
PROVIDER: S-EPMC3922866 | biostudies-other | 2014 Feb
REPOSITORIES: biostudies-other
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Project description:PURPOSE: Partial wrist arthrodesis is a commonly performed procedure for the treatment of posttraumatic wrist arthritis because of its ability to provide pain relief without sacrificing complete wrist motion. The purpose of this study was to evaluate the redistribution of force after four-corner fusion and scaphoid excision, and to correlate the findings with the reported clinical outcomes. METHODS: Fifteen cadaveric wrists were used to study the biomechanics of the four-corner fusion. Pressure-sensitive film (super-low-pressure-indicating film-Pressurex, Sensor Products Inc, Madison, NJ) was inserted into the radiocarpal joint. Using the MTS 858 Mini Bionix (MTS System, Eden Prairie, MN), 50-kg loads (220 N) were applied to the wrists before and after simulated four-corner fusion and scaphoid excision. Statistically, we compared the pressure in the normal (intact) wrists versus four-corner fusion and scaphoid excision. The pressure measurements across the scaphoid fossa, lunate fossa, and triangular fibrocartilage complex (TFCC) were compared. RESULTS: There is a statistical significant difference between scaphoid, lunate, and TFCC mean total force when pre and post-fusion were compared (p = 0.0001). Our study revealed a statistical significant decrease in the mean scaphoid total force after scaphoid excision and four-corner fusion (p = 0.0001). We also found a subsequent increase in mean total force after scaphoid excision and four-corner fusion for the lunate fossa that did not reach statistical significance (p = 0.08), and no difference in load across the TFCC area (p = 0.995). CONCLUSIONS: Our findings suggest that load is preferentially transferred to the radiolunate joint after scaphoid excision with four-corner fusion.
| S-EPMC2527225 | biostudies-other
Project description:The purpose of this study was to compare the clinical outcome, union rate, and complications of a consecutive series of Scaphoid excision and limited wrist arthrodesis performed by a single surgeon using distal radius bone graft and K-wires or circular plate fixation. A sequential series of ten patients(11 wrists) who were stabilized with temporary K-wires were compared to 11 patients (11 wrists) who were stabilized with a circular plate. Minimum follow-up was 1 year. One patient in the K-wire group was converted to a wrist fusion. Six of the remaining ten patients in the K-wire fixation group and 8 of the 11 patients in the circular plate fixation group returned for the following blinded evaluations: Quick DASH, analog pain scale, range of motion, grip and pinch strength, plain x-ray, and multi-detector computed tomography evaluation. One non-union occurred in the K-wire group. There were no non-unions in the circular plate fixation group. There was no difference in any of remaining measures or rate of complications. This study shows that equivalent results can be obtained using circular plate fixation compared to K-wires when equivalent bone graft source and fusion technique are used. If K-wire removal requires a return to the OR, circular plate fixation is more cost-effective.
| S-EPMC2525875 | biostudies-other
Project description:Background Malunions following distal radius fractures are common, with shortening, translation, and rotation occurring. The patients frequently lose forearm rotation, but there is no data to indicate whether this is due to mechanical misalignment between the radius and the ulna or to contracture of the soft tissues. Material and Methods Seven fresh cadaveric specimens were used to determine the loss of forearm rotation with varying simulated distal radius fracture malalignment patterns. Uniplanar malunion patterns consisting of dorsal tilt, radioulnar translation, or radial shortening were simulated by creating an osteotomy at the distal end of the radius. Description of Technique By orienting the distal fragment position using an external fixator and maintaining the position with wedges and a T-plate, varying degrees of malunion of the distal radius could be simulated. Rotation of the forearm was produced by fixing the elbow in a flexed position and applying a constant torque to the forearm using deadweights. Forearm rotation was measured with a protractor. Results Dorsal tilt to 30° and radial translation to 10 mm led to no significant restriction in forearm pronation or supination ranges of motion. A 5-mm ulnar translation deformity resulted in a mean 23% loss of pronation range of motion. Radial shortening of 10 mm reduced forearm pronation by 47% and supination by 29%. Conclusion Because a severe osseous misalignment was required to produce a significant loss in rotation, contracture of the soft tissues is most likely the cause of the loss of rotation in most cases.
| S-EPMC3922873 | biostudies-other
Project description:BackgroundThe transfer of flexor-to-extensor is widely used to correct lesser toe deformity and joint instability. The flexor digitorum longus tendon (FDLT) is percutaneously transected at the distal end and then routed dorsally to the proximal phalanx. The transected tendon must have enough mobility and length for the transfer. The purpose of this study was to dissect the distal end of FDLT and identify the optimal technique to percutaneously release FDLT.MethodsEight fresh adult forefoot specimens were dissected to describe the relationship between the tendon and the neurovascular bundle and measure the width and length of the distal end of FDLT. Another 7 specimens were used to create the percutaneous release model and test the strength required to pull out FDLT proximally. The tendons were randomly released at the base of the distal phalanx (BDP), the space of the distal interphalangeal joint (SDIP), and the neck of the middle phalanx (NMP).ResultsAt the distal interphalangeal (DIP) joint, the neurovascular bundle begins to migrate toward the center of the toe and branches off toward the center of the toe belly. The distal end of FDLT can be divided into 3 parts: the distal phalanx part (DPP), the capsule part (CP), and the middle phalanx part (MPP). There was a significant difference in width and length among the 3 parts. The strength required to pull out FDLT proximally was about 168, 96, and 20 N, respectively, for BDP, SDIP, and NMP.ConclusionThe distal end of FDLT can be anatomically described at 3 locations: DPP, CP, and MPP. The tight vinculum brevis and the distal capsule are strong enough to resist proximal retraction. Percutaneous release at NMP can be performed safely and effectively.Clinical relevancePercutaneous release at NMP can be performed safely and effectively during flexor-to-extensor transfer.
| S-EPMC8697276 | biostudies-literature
Project description:BackgroundTransforaminal lumbar interbody fusion (TLIF) is an effective surgery for lumbar degenerative disease. However, this fusion technique requires resection of inferior facet joint to provide access for superior facet joint resection, which results in reduced lumbar spinal stability and unnecessary trauma. We have previously developed extraforaminal lumbar interbody fusion (ELIF) that can avoid back muscle injury with direct nerve root decompression. This study aims to show that ELIF enhances lumbar spinal stability in comparison to TLIF by comparing lumbar spinal stability of L4-L5 range of motion (ROM) on 12 cadaveric spine specimens after performing TLIF or ELIF.Methods12 cadaveric spine specimens were randomly divided and treated in accordance with the different internal fixations, including ELIF with a unilateral pedicle screw (ELIF+UPS), TLIF with a unilateral pedicle screw (TLIF+UPS), TLIF with a bilateral pedicle screw (TLIF+BPS), ELIF with a unilateral pedicle screw and translaminar facet screw (ELIF+UPS+TLFS) and ELIF with a bilateral pedicle screw (ELIF+BPS). The treatment groups were exposed to a 400-N load and 6 N·m movement force to calculate the angular displacement of L4-L5 during anterior flexion, posterior extension, lateral flexion and rotation operation conditions.ResultsThe ROM in ELIF+UPS group was smaller than that of TLIF+UPS group under all operating conditions, with the significant differences in left lateral flexion and right rotation by 36.15% and 25.97% respectively. The ROM in ELIF+UPS group was higher than that in TLIF+BPS group. The ROM in the ELIF+UPS+TLFS group was much smaller than that in the ELIF+UPS group, but was not significantly different than that in the TLIF+BPS group.ConclusionsDespite that TLIF+BPS has great stability, which can be comparable by that of ELIF+UPS. Additionally, ELIF stability can be further improved by using translaminar facet screws without causing more tissue damage to patient.
| S-EPMC5178989 | biostudies-literature
Project description:BackgroundThis investigation's purpose was to perform a systematic review of the literature examining the biomechanics of the ligaments comprising the distal tibiofibular syndesmosis with specific attention to their resistance to translational and rotational forces. Although current syndesmosis repair techniques can achieve an anatomic reduction, they may not reapproximate native ankle biomechanics, resulting in loss of reduction, joint overconstraint, or lack of external rotation resistance. Armed with a contemporary understanding of individual ligament biomechanics, future operative strategies can target key stabilizing structure(s), translating to a repair better equipped to resist anatomic displacing forces.Study designSystematic review.MethodsA systematic review was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines using a PRISMA checklist. Biomechanical studies testing cadaveric lower limb specimens in the intact and injured state measuring the distal tibiofibular syndesmosis resistance to translational and rotational forces were included in this review. Only studies that included numerical data were included in this review; studies that only reported figures and graphs were excluded.ResultsTwelve studies met the inclusion and exclusion criteria. Two studies determined the mechanical properties of syndesmotic ligaments, finding superior strength and stiffness of the interosseous ligament (IOL), as compared to the anterior (AITFL) or posteroinferior tibiofibular ligament (PITFL). Four studies examined native ankle biomechanics establishing physiologic range of motion of the fibula relative to the tibia. Fibular range of motion was found to be up to 2.53 mm of posterior translation (Markolf et al), 1.00 mm lateral translation (Xenos et al), 3.6 degrees of external rotation (Burssens et al), and 1.4 degrees of internal rotation (Clanton et al). Four studies evaluated syndesmotic biomechanics under physiological loading and found that the AITFL, IOL, and PITFL provide the majority of resistance to external rotation, diastasis, and internal rotation, respectively. Two studies investigated the biomechanics of clinically and intraoperatively used tests for syndesmotic injuries and found increased sensitivity of sagittal plane posterior fibular translation, as opposed to coronal plane lateral fibular translation for unstable injuries.ConclusionsStudy findings suggest that although the IOL is the strongest syndesmotic ligament, the AITFL has a dominant role stabilizing the distal tibiofibular syndesmosis to external rotation force. Because of these characteristics, operative repair of the AITFL along its native vector may provide a more biomechanically advantageous construct and should be investigated clinically. Additionally, evaluation of clinical stress tests revealed that the external rotation stress test is the most sensitive test to recognize an AITFL tear, and that a 3-ligament disruption is needed to cause diastasis greater than 2 mm.
| S-EPMC8702939 | biostudies-literature
Project description:The distal great saphenous vein is a popular site for venous access by means of percutaneous cannulation or venous cutdown in a hemodynamically unstable patient. The aim of this study was to precisely define the surface anatomy and dimensions of the distal part of the great saphenous vein to facilitate the aforementioned procedures. Cross-sectional anatomy of the distal saphenous vein was studied in 24 cadaveric ankles sectioned at a horizontal plane across the most prominent points of the medial and lateral malleoli. The curvilinear distance from the most prominent point of the medial malleolus to the center of the saphenous vein, its widest collapsed diameter and skin depth were obtained. The great saphenous vein was located at a mean distance of 24.4 ± 7.9 mm anterior to the medial malleolus. The mean widest collapsed diameter was 3.8 ± 1.5 mm. The mean distance from the skin surface to the vein was 4.1 ± 1.2 mm. These measurements could be used to locate the saphenous vein accurately, particularly in hemodynamically unstable patients with visually indiscernible veins.
| S-EPMC9872368 | biostudies-literature
Project description:BackgroundThe posterior plating technique could be used as a clinical alternative to parallel plating for treating comminuted distal humerus fractures (DHFs) successfully with good clinical results. However, the biomechanical characteristics for posterior fixation are still unclear. The purpose of this study is to evaluate the biomechanical properties of the posterior fixation and to make comparisons between the parallel and the posterior fixation systems.Materials and methodsWe performed a cadaveric biomechanical testing with two posterior plating systems (a posterior two plating and a single posterior pre-contoured Y plating system) and one parallel two plating system to treat AO/OTA type-C2.3 DHFs. Among three groups, we compared construct stiffness, failure strength, and intercondylar width changes after 5000-cycle fatigue loading and failure loads and failure modes after destructive tests in both the axial compression and (sagittal) posterior bending directions. The correlations between construct failure loads and bone marrow density (BMD) were also compared.ResultsIn axial direction, there were no significant differences in the stiffness and failure load between the posterior and the parallel constructs. However, in sagittal direction, the two-plate groups (posterior two plating and parallel plating group) had significant higher stiffness and failure loads than the one-plate group (single posterior Y plating). There was no fixation failure after 5000-cyclic loading in both directions for all groups. Positive correlation was noted between BMD and failure loads on parallel fixation.ConclusionsWe found that when using two plates for treating comminuted DHFs, there were no significant differences in terms of most biomechanical measurements between posterior and parallel fixation. However, the single pre-contoured posterior Y plate construct was biomechanically weaker in the sagittal plane than the parallel and the posterior two-plate constructs, although there was no fixation failure after the fatigue test for all groups regardless of the fixation methods.Level of evidenceBiomechanical study.
| S-EPMC8122534 | biostudies-literature
Project description:BackgroundTotal ankle arthroplasty (TAA) is becoming a more prevalent treatment for end-stage ankle arthritis. However, the effects of malalignment on TAA remain poorly understood.Questions/purposesThe purpose of this study was to quantify the mechanical effects of coronal plane malalignment of the tibial insert in TAA using cadaveric gait simulation. Specifically, we asked, is there a change in (1) ankle joint congruency, (2) kinematic joint position, (3) kinematic ROM, (4) peak plantar pressure, and (5) center of pressure with varus and valgus malalignment?MethodsA modified TAA was implanted into seven cadaveric foot specimens. Wedges were used to simulate coronal plane malalignment of the tibial insert. The degree of malalignment (tibial insert angle [TIA] and talar component angle [TCA]) was quantified radiographically for neutral and 5°, 10°, and 15° varus and valgus wedges. Dynamic walking at 1/6 of physiological speed was simulated using a robotic gait simulator. A motion capture system was used to measure foot kinematics, and a pressure mat was used to measure plantar pressure. Joint congruency was quantified as the difference between TIA and TCA. Continuous joint position, joint ROM, peak plantar pressure, and center of pressure for varus and valgus malalignment compared with neutral alignment were estimated using linear mixed effects regression. Pairwise comparisons between malalignment conditions and neutral were considered significant if both the omnibus test for the overall association between outcome and malalignment and the individual pairwise comparison (adjusted for multiple comparisons within a given outcome) had p ≤ 0.05.ResultsDescriptively, the TIA and TCA were both less pronounced than the wedge angle and component incongruence was seen (R = 0.65; p < 0.001). Varus malalignment of the tibial insert shifted the tibiotalar joint into varus and internally rotated the joint. The tibiotalar joint's ROM slightly increased as the TIA shifted into varus (1.3 ± 0.7° [mean ± SD] [95% confidence interval -0.7 to 3.4]; p = 0.03), and the first metatarsophalangeal joint's ROM decreased as the TIA shifted into varus (-1.9 ± 0.9° [95% CI -5.6 to 1.7]; p = 0.007). In the sagittal plane, the naviculocuneiform joint's ROM slightly decreased as the TIA shifted into varus (-0.9 ± 0.4° [95% CI -2.1 to 0.3]; p = 0.017). Hallux pressure increased as the TIA became more valgus (59 ± 50 kPa [95% CI -88 to 207]; p = 0.006). The peak plantar pressure slightly decreased in the third and fourth metatarsals as the TIA shifted into valgus (-15 ± 17° [95% CI -65 to 37]; p = 0.03 and -8 ± 4° [95% CI -17 to 1]; p = 0.048, respectively). The fifth metatarsal's pressure slightly decreased as the TIA shifted into valgus (-18 ± 12 kPa [95% CI -51 to 15]) or varus (-7 ± 18 kPa [95% CI -58 to 45]; p = 0.002). All comparisons were made to the neutral condition.ConclusionsIn this cadaver study, coronal plane malalignment in TAA altered foot kinematics and plantar pressure. In general, varus TAA malalignment led to varus shift and internal rotation of the tibiotalar joint, a slight increase in the tibiotalar ROM, and a slight decrease in the first metatarsophalangeal ROM, while a valgus TAA malalignment was manifested primarily through increased hallux pressure with a slight off-loading of the third and fourth metatarsals.Clinical relevanceThis study may increase our understanding of the biomechanical processes that underlie the unfavorable clinical outcomes (such as, poor patient-reported outcomes or implant loosening) that have been associated with coronal plane malalignment of the tibial component in TAA.
| S-EPMC7310376 | biostudies-literature
Project description:A thorough knowledge of the anatomy of the terminal branch of the posterior interosseous nerve (PIN) and its relationship to the anterior interosseous nerve (AIN) is essential in facilitating regional anesthetic blocks and planning surgical exposures for wrist surgery and arthrodesis of wrist and proximal row carpectomy. This cadaveric study focused on the anatomy and course of the PIN and its anatomical relationships at the distal forearm. Thirty embalmed cadaver forearms were dissected using microsurgical techniques. A structured pro forma was used to collect data. The PIN was consistently found in the fourth extensor compartment in all specimens. The last motor branch was given off 46.9 ± 8.4 mm (mean ± standard deviation) from the most proximal part of the ulnar head. The AIN was found lying consistently on the anterior aspect of the interosseous membrane, being on average 2.8 ± 0.2 mm (mean ± standard deviation) from the PIN. This knowledge will facilitate the planning of diagnostic and therapeutic procedures associated with the wrist.
| S-EPMC3922858 | biostudies-other