Distal radial metaphyseal forces in an extrinsic grip model: Implications for postfracture rehabilitation

Putnam, Matthew D.; Meyer, Nicholas J.; Nelson, Eric; Gesensway, David; Lewis, Jack L.

doi:10.1053/jhsu.2000.6915

Cited by 105 publications

(68 citation statements)

References 11 publications

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“…Forces were consistent with previously published biomechanical testing of distal radius fixation and studies demonstrating that light active motion of the wrist and wrist with finger motion does not exceed 250N. (12,15,(17)(18)(19)(20)(21)(22)(23)(24) Gondusky et al and Weninger et al identified in prior distal radius mechanical testing that all changes attributable to cyclic loading occurred in the first 200-500 cycles, thus we deemed 1,000 cycles sufficient to condition the constructs. (11,(13)(14)(15)(16) Destructive testing was completed to determine load (N) to clinical failure which was defined as 2mm of displacement at the osteotomy gap, (10) and subsequent catastrophic failure, defined as complete closure of the 1 cm osteotomy gap and or fracture.…”

Section: Biomechanical Testingsupporting

confidence: 87%

“…Light active wrist motion is anticipated to result in 100N of force with digital flexion increasing this up to 250N based on load created by extrinsic finger flexors in a position of grip. (19)(20)(21)23) Despite these widely referenced values, the distribution of forces between the radius and ulna are expected to vary depending on radioulnar variance, and the forces across the radius during rehabilitation likely vary between axial load, volar bending, dorsal bending, and torsion forces. We focused on evaluating failure under axial compression rather than bending stiffness, as axial loads against the 250N standard are believed to be the major failure force in vivo.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

The Effects of Screw Length on Stability of Simulated Osteoporotic Distal Radius Fractures Fixed with Volar Locking Plates

Wall¹,

Brodt²,

Silva³

2012

The Journal of Hand Surgery

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Purpose-Volar plating for distal radius fractures has caused extensor tendon ruptures secondary to dorsal screw prominence. This study was designed to determine the biomechanical impact of placing unicortical distal locking screws and pegs in an extra-articular fracture model.Methods-Volar-locking distal radius plates were applied to 30 osteoporotic distal radius models. Radii were divided into 5 groups based on distal locking fixation: bicortical locked screws, 3 lengths of unicortical locked screws (abutting the dorsal cortex [full length], 75% length, and 50% length to dorsal cortex), and unicortical locked pegs. Distal radius osteotomy simulated a dorsally comminuted, extra-articular, fracture. Each constructs stiffness was determined under physiologic loads (axial compression, dorsal bending volar bending) before and after 1000 cycles of axial conditioning and prior to axial loading to failure (2mm of displacement) and subsequent catastrophic failure.Results-Cyclic conditioning did not alter constructs stiffness. Stiffness to volar bending and dorsal bending forces were similar between groups. Final stiffness(N/mm) under axial load was statistically equivalent for all groups: bicortical screws(230), full-length unicortical screws(227), 75% length unicortical screws(226), 50% length unicortical screws(187), unicortical pegs(226). Force(N) at 2 mm displacement was significantly less for 50% length unicortical screws(311) compared to bicortical screws(460), full-length unicortical screws(464), 75% length unicortical screws(400), and unicortical pegs(356). Force(N) to catastrophic fracture was statistically equivalent between groups but mean values for pegs(749) and 50% length unicortical(702) screws were 16-21% less than means for bicortical(892), full-length unicortical(860), and 75% length(894) unicortical constructs.Discussion-Locked unicortical distal screws of at least 75% length produce construct stiffness similar to bicortical fixation. Unicortical distal fixation for extra-articular distal radius fractures should be entertained to avoid extensor tendon injury since it does not appear to compromise initial fixation. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access

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Section: Biomechanical Testingsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

The Effects of Screw Length on Stability of Simulated Osteoporotic Distal Radius Fractures Fixed with Volar Locking Plates

Wall¹,

Brodt²,

Silva³

2012

The Journal of Hand Surgery

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“…The construct was deemed to pass the test if its failure load was greater than 400 N and its stiffness was greater than 80 N/mm. These cutoff values were chosen to be twice the loads applied to the wrist during active digital flexion (an activity promoted immediately postoperatively in clinical care to reduce swelling, pain, and finger stiffness) but less than those achievable by experts using modern plate fixation [5,8,14].…”

Section: Study 2: Mechanical Construct Stability In An Extraarticularmentioning

confidence: 99%

“…For instance, in the case of intraarticular fracture reduction, performance evaluation should consider the precision with which the joint is restored, an important factor in determining the likelihood of posttraumatic osteoarthritis [2,4]. Similarly, in the case of extraarticular fracture reduction, performance evaluation should consider the strength of the associated fixation construct, because the construct serves to maintain the reduction during the course of early recovery and its mechanical integrity substantially influences fracture healing [14]. Previous work in surgical skills assessment and training has rarely addressed these objective metrics of surgical performance.…”

Section: Introductionmentioning

confidence: 99%

Objective Structured Assessments of Technical Skills (OSATS) Does Not Assess the Quality of the Surgical Result Effectively

Anderson

Long

Thomas

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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Background Performance assessment in skills training is ideally based on objective, reliable, and clinically relevant indicators of success. The Objective Structured Assessment of Technical Skill (OSATS) is a reliable and valid tool that has been increasingly used in orthopaedic skills training. It uses a global rating approach to structure expert evaluation of technical skills with the experts working from a list of operative competencies that are each rated on a 5-point Likert scale anchored by behavioral descriptors. Given the observational nature of its scoring, the OSATS might not effectively assess the quality of surgical results. Questions/purposes (1) Does OSATS scoring in an intraarticular fracture reduction training exercise correlate with the quality of the reduction? (2) Does OSATS scoring in a cadaveric extraarticular fracture fixation exercise correlate with the mechanical integrity of the fixation?Methods Orthopaedic residents at the University of Iowa (six postgraduate year [PGY]-1s) and at the University of Minnesota (seven PGY-1s and eight PGY-2s) undertook a skills training exercise that involved reducing a simulated intraarticular fracture under fluoroscopic guidance. Iowa residents participated three times during 1 month, and Minnesota residents participated twice with 1 month between their two sessions. A fellowship-trained orthopaedic traumatologist rated each performance using a modified OSATS scoring scheme. The quality of the articular reduction obtained was then directly measured. Regression analysis was performed between OSATS scores and two metrics of articular reduction quality: articular surface deviation and estimated contact stress. Another skills training exercise involved fixing a simulated distal radius fracture in a cadaveric specimen. Thirty residents, distributed across four PGY classes (PGY-2 and PGY-3, Clinical Orthopaedics and Related Research ®A Publication of The Association of Bone and Joint Surgeons® n = 8 each; PGY-4 and PGY-5, n = 7 each), simultaneously completed the exercise at individual stations. One of three faculty hand surgeons independently scored each performance using a validated OSATS scoring system. The mechanical integrity of each fixation construct was then assessed in a materials testing machine. Regression analysis was performed between OSATS scores and two metrics of fixation integrity: stiffness and failure load. Results In the intraarticular fracture model, OSATS scores did not correlate with articular reduction quality (maximum surface deviations: R = 0.17, p = 0.25; maximum contact stress: R = 0.22, p = 0.13). Similarly in the cadaveric extraarticular fracture model, OSATS scores did not correlate with the integrity of the mechanical fixation (stiffness: R = 0.10, p = 0.60; failure load: R = 0.30, p = 0.10). Conclusions OSATS scoring methods do not effectively assess the quality of the surgical result. Efforts must be made to incorporate assessment metrics that reflect the quality of the surgical result. Clinical Relevance New objectiv...

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“…' for perfect realignment of the joint surface; we believe that quality of the reduction matters [1]. Additionally, we strive for fixation stability [5]. Aside from directly checking patient outcomes that usually can only be measured long after a procedure-and so are hard to use for the assessment of trainees-reduction quality and mechanical integrity are probably as close as we can get to measuring how well an operation was performed.…”

mentioning

confidence: 99%

Editor's Spotlight/Take 5: Objective Structured Assessments of Technical Skills (OSATS) Does Not Assess the Quality of the Surgical Result Effectively

Wongworawat

2016

Clinical Orthopaedics &Amp; Related Research

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Distal radial metaphyseal forces in an extrinsic grip model: Implications for postfracture rehabilitation

Cited by 105 publications

References 11 publications

The Effects of Screw Length on Stability of Simulated Osteoporotic Distal Radius Fractures Fixed with Volar Locking Plates

The Effects of Screw Length on Stability of Simulated Osteoporotic Distal Radius Fractures Fixed with Volar Locking Plates

Objective Structured Assessments of Technical Skills (OSATS) Does Not Assess the Quality of the Surgical Result Effectively

Editor's Spotlight/Take 5: Objective Structured Assessments of Technical Skills (OSATS) Does Not Assess the Quality of the Surgical Result Effectively

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