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Zdero R, Brzozowski P, Schemitsch EH. Biomechanical design optimization of proximal humerus locked plates: A review. Injury 2024; 55:111247. [PMID: 38056059 DOI: 10.1016/j.injury.2023.111247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/15/2023] [Accepted: 11/24/2023] [Indexed: 12/08/2023]
Abstract
BACKGROUND Proximal humerus locked plates (PHLPs) are widely used for fracture surgery. Yet, non-union, malunion, infection, avascular necrosis, screw cut-out (i.e., perforation), fixation failure, and re-operation occur. Most biomechanical investigators compare a specific PHLP configuration to other implants like non-locked plates, nails, wires, and arthroplasties. However, it is unknown whether the PHLP configuration is biomechanically optimal according to some well-known biomechanical criteria. Therefore, this is the first review of the systematic optimization of plate and/or screw design variables for improved PHLP biomechanical performance. METHODS The PubMed website was searched for papers using the terms "proximal humerus" or "shoulder" plus "biomechanics/biomechanical" plus "locked/locking plates". PHLP papers were included if they were (a) optimization studies that systematically varied plate and screw variables to determine their influence on PHLP's biomechanical performance; (b) focused on plate and screw variables rather than augmentation techniques (i.e., extra implants, bone struts, or cement); (c) published after the year 2000 signaling the commercial availability of locked plate technology; and (d) written in English. RESULTS The 41 eligible papers involved experimental testing and/or finite element modeling. Plate variables investigated by these papers were geometry, material, and/or position, while screw variables studied were number, distribution, angle, size, and/or threads. Numerical outcomes given by these papers included stiffness, strength, fracture motion, bone and implant stress, and/or the number of loading cycles to failure. But, no paper fully optimized any plate or screw variable for a PHLP by simultaneously applying four well-established biomechanical criteria: (a) allow controlled fracture motion for early callus generation; (b) reduce bone and implant stress below the material's ultimate stress to prevent failure; (c) maintain sufficient bone-plate interface stress to reduce bone resorption (i.e., stress shielding); and (d) increase the number of loading cycles before failure for a clinically beneficial lifespan (i.e., fatigue life). Finally, this review made suggestions for future work, identified clinical implications, and assessed the quality of the papers reviewed. CONCLUSIONS Applying biomechanical optimization criteria can assist biomedical engineers in designing or evaluating PHLPs, so orthopaedic surgeons can have superior PHLP constructs for clinical use.
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Affiliation(s)
- Radovan Zdero
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada
| | - Pawel Brzozowski
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada.
| | - Emil H Schemitsch
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada; Division of Orthopaedic Surgery, Western University, London, ON, Canada
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Saunders PE, Castaneda P, Walker R, McKee MD. Biomechanical comparison of tuberosity-based proximal humeral locking plate compared to standard proximal humeral locking plate in varus cantilever bending. Injury 2022; 53:3650-3654. [PMID: 36057488 DOI: 10.1016/j.injury.2022.08.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 08/11/2022] [Accepted: 08/16/2022] [Indexed: 02/02/2023]
Abstract
PURPOSE In a prior biomechanical study using a tuberosity-based proximal humeral locking plate (TBP) an improvement in greater tuberosity (GT) fixation strength with the TBP compared to a standard proximal humeral locking plate (PHLP) was demonstrated. The purpose of this study is to compare the TBP to the PHLP with a simulated calcar gap fracture under cyclic varus cantilever forces. METHODS Seven matched pairs of cadaveric humeri were studied and 11A2.3 proximal humerus fractures were created by a 1 cm gap osteotomy at the surgical neck. Matched pairs were randomized for fixation using either a PHLP or a TBP. The proximal articular aspect of the humerus was potted and secured to the base of a load frame. The shaft was subjected to cyclic varus cantilever loading with a roller positioned 8 cm from the osteotomy. Change in vertical displacement of the diaphyseal fragment was monitored and digital images were obtained. Failure was defined as vertical displacement greater than 20 mm. Specimens not exhibiting failure over the course of 10,000 cycles were then loaded to 20 mm of vertical displacement. Reactant forces of the specimens at these displacements were recorded. RESULTS Four/seven TBP specimens and four/seven PHLP specimens survived 10,000 cycles. The average cycles to failure for TBP specimens was 7325 cycles and 5715 cycles for PHLP specimens (p = 0.525). For the specimens that survived 10,000 cycles, the decrease in calcar gap was superior in the TBP specimens (p = 0.018). A similar trend was seen when these specimens were loaded to failure where the percent calcar gap recovery was higher for the TBP at 74.71 ± 10.07% versus 53.22 ± 30.35% for the PHLP (p = 0.072). In specimens that were loaded to failure after survival of 10,000 cycles the average stiffness of the TBP construct was 20.51 N/mm, and 11.74 N/mm for the PHLP construct (p = 0.024). CONCLUSION In addition to superior GT fixation shown in a prior study, the TBP construct demonstrates significantly greater stiffness at the neck fracture compared to the PHLP, when loaded to failure. In addition, there was a trend towards less collapse in this calcar gap model.
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Affiliation(s)
- Patrick E Saunders
- Department of Orthopaedic Surgery, University of Arizona College of Medicine - Phoenix, 1111 E. McDowell Road, Phoenix, AZ, 85006.
| | - Paulo Castaneda
- Department of Orthopaedic Surgery, University of Arizona College of Medicine - Phoenix, 1111 E. McDowell Road, Phoenix, AZ, 85006
| | - Robert Walker
- Department of Orthopaedic Surgery, University of Arizona College of Medicine - Phoenix, 1111 E. McDowell Road, Phoenix, AZ, 85006
| | - Michael D McKee
- Department of Orthopaedic Surgery, University of Arizona College of Medicine - Phoenix, 1111 E. McDowell Road, Phoenix, AZ, 85006
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Bønes I, Karlberg AC, Liljeholm M, Fraser AN, Madsen JE, Fjalestad T. Pegs not superior to screws for fixation of fractures of the proximal humerus. J Orthop Surg Res 2022; 17:66. [PMID: 35109905 PMCID: PMC8812225 DOI: 10.1186/s13018-022-02947-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/21/2022] [Indexed: 11/17/2022] Open
Abstract
Background Angular stable plates were introduced two decades ago as a promising treatment for fixation of displaced fractures of the proximal humerus (PHF). However, high rates of adverse events and reoperations have been reported. One frequent reason is secondary penetration of screws into the glenohumeral joint, due to sinking of the fracture or avascular head necrosis. To prevent joint penetrations angular stable plates with smooth locking pegs instead of locking screws have been developed. The aim of the present study was to investigate whether blunt pegs instead of pointed screws reduced the risk of secondary penetration into the glenohumeral joint during fracture healing after operatively treated PHFs. Methods From two different patient cohorts with displaced PHFs (60 treated with PHILOS plate with screws and 50 with ALPS-PHP plate with pegs), two groups were matched according to fracture type AO/OTA 11-B2 and 11-C2 and age (55–85 years). They were followed up at 3, 6 and 12 months. Primary outcome was radiographic signs of peg or screw penetrations into the glenohumeral joint at 12 months. Secondary outcomes were Oxford shoulder score (OSS) and Constant Score (CS) and radiographic signs of avascular humeral head necrosis (AVN). Results Eighteen PHILOS patients with B2 and C2 fractures could be matched with a corresponding group of 18 operated with ALPS-PHP with pegs. The number of penetrations of pegs and screws were equal between the two groups and the development of avascular head necrosis did not differ either. The functional outcomes for both OSS and CS at 12 months was clearly in favor of patients without joint penetrations in both groups. Conclusion We found no differences in the number of screw or peg penetrations in the PHILOS and ALPS-PHP group and the occurrence of AVN was equal. Joint penetrations led to inferior functional outcomes at 1 year. The ClinicalTrials.gov identifier 20/11/12 prospectively for the Philos Group is NCT01737060, and for the ALPS group 11/03/20 retrospectively is NCT04622852.
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Affiliation(s)
- Ingrid Bønes
- Division of Orthopaedic Surgery (I.B., ML, J.E.M., T.F.), Oslo University Hospital, Postboks 4956, 0424, Nydalen, Oslo, Norway
| | - Anna Cecilie Karlberg
- Division of Radiology and Nuclear Medicine, Department of Musculoskeletal Radiology (A.C.K.), Oslo University Hospital, Oslo, Norway
| | - Maria Liljeholm
- Division of Orthopaedic Surgery (I.B., ML, J.E.M., T.F.), Oslo University Hospital, Postboks 4956, 0424, Nydalen, Oslo, Norway
| | | | - Jan Erik Madsen
- Division of Orthopaedic Surgery (I.B., ML, J.E.M., T.F.), Oslo University Hospital, Postboks 4956, 0424, Nydalen, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Tore Fjalestad
- Division of Orthopaedic Surgery (I.B., ML, J.E.M., T.F.), Oslo University Hospital, Postboks 4956, 0424, Nydalen, Oslo, Norway.
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Gonzalez-Hernandez E, Pietrzak WS, Jain S, Lapica HE. Cross-elements to enhance fixation in osteoporotic bone with application to proximal humeral locking plates: a biomechanical study. J Shoulder Elbow Surg 2020; 29:1606-1614. [PMID: 32147335 DOI: 10.1016/j.jse.2019.12.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 12/06/2019] [Accepted: 12/10/2019] [Indexed: 02/01/2023]
Abstract
BACKGROUND Proximal humeral fractures occur predominantly in elderly, osteoporotic individuals, especially women, with surgery performed in one-fifth. Proximal humeral locking plates are the gold standard operative treatment; however, complications are frequent, partially because of poor screw purchase in osteoporotic bone. A new method uses threaded posts through which threaded cross-elements orthogonally pass to create a 3-dimensional scaffold for bone engagement. We examined the pullout characteristics of the posts with (1 or 2) or without the cross-elements and tested 2 types of 3.5-mm cortical locking screws for comparison. METHODS Low-density closed-cell polyurethane foam served as a model osteoporotic bone substrate. Following implantation in the substrate, the devices were axially loaded by a mechanical test system. Quantities of interest included failure mode, peak load, displacement to peak load, initial stiffness, and work expended. RESULTS The post groups outperformed the 3.5-mm screw groups, as expected. Relative to posts with no cross-elements, 1 and 2 cross-elements increased the peak load by 29% and 87% and increased the work to peak load by 126% and 343%, respectively. After reaching peak load, 1 and 2 cross-elements increased the work-resistance to further displacement by 158% and 330%, respectively. CONCLUSION Cross-elements significantly increased the ability of the threaded posts to resist axial displacement from a model osteoporotic bone substrate. This suggests that posts, used in conjunction with cross-elements, have the potential to enhance the stability of proximal humeral locking plates in osteoporotic bone.
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Affiliation(s)
| | - William S Pietrzak
- Musculoskeletal Publication and Analysis, Inc., Warsaw, IN, USA; Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA.
| | | | - Hans E Lapica
- Florida International University, Herbert Wertheim College of Medicine, Miami, FL, USA
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5
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Hansson F, Riddar M, Ekelund A. Evaluation of open reduction and internal fixation of proximal humerus fractures using a locking plate with smooth pegs - A retrospective study. Shoulder Elbow 2019; 11:411-418. [PMID: 32269600 PMCID: PMC7094065 DOI: 10.1177/1758573218791166] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 04/19/2018] [Accepted: 07/03/2018] [Indexed: 11/16/2022]
Abstract
BACKGROUND Optimal treatment of displaced proximal humeral fractures is controversial. This retrospective study aims to identify complications and clinical outcomes using a locking plate with smooth pegs instead of screws (S3 plate). METHOD Eighty-two patients with displaced proximal humeral fracture classified with 2-4 fragments (Neer's classification) treated with open reduction and internal fixation (ORIF) with S3 plate were studied retrospectively. Clinical outcome according to constant score; Single Shoulder Value; Disabilities of Arm, Shoulder and Hand; and European Quality of life-5 dimensions and complication rate defined radiologically including peg penetration, avascular necrosis, and loss of reduction was assessed minimum 2.5 years after surgery. RESULTS A total of 11 peg penetrations were identified (13.6%). Avascular necrosis was seen in 8.5% (n = 7). Mean constant score at follow-up was 64.4 with a relative constant score of 87% (standard deviation 18%) compared to the contralateral uninjured side. The mean Disabilities of Arm, Shoulder and Hand score was 12.7 and mean European Quality of life-5 dimensions score 0.83. The mean Single Shoulder Value was 78.3. No cases of deep infection were seen. CONCLUSIONS Fixation with S3 plate shows a proper osteosynthesis and the functional outcome is good. Symptomatic peg penetrations are rare and the incidence is lower compared to what has been reported with locked screws.
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Affiliation(s)
- Frida Hansson
- Frida Hansson, Department of Orthopaedics,
Capio St Görans Hospital, Stockholm SE-11281, Sweden.
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Jabran A, Peach C, Zou Z, Ren L. Biomechanical comparison of screw-based zones of a spatial subchondral support plate for proximal humerus fractures. Proc Inst Mech Eng H 2019; 233:372-382. [PMID: 30700217 DOI: 10.1177/0954411919827984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Stabilisation of proximal humerus fractures remains a surgical challenge. Spatial subchondral support (S3) plate promises to overcome common complications associated with conventional proximal humerus plates. This study compared the biomechanical performance of S3 plate with a fixed-angle hybrid blade (Equinoxe Fx) plate and a conventional fixed-angle locking plate (PHILOS). The effects of removal of different S3 plate screws on the humeral stability were also investigated. A total of 20 synthetic left humeri were osteotomised transversely at the surgical neck to simulate a two-part fracture and were each treated with an S3 plate. Head screws were divided into three zones based on their distance from the fracture site. Specimens were divided into four equal groups where one group acted as a control with all screws and three groups had one of the screw zones missing. With humeral head fixed, humeral shaft was first displaced 5 mm in extension, flexion, valgus and varus direction (elastic testing) and then until 30 mm varus displacement (plastic testing). Load-displacement data were recorded to determine construct stiffness in elastic tests and assess specimens' varus stability under plastic testing. Removal of the screw nearest to the fracture site led to a 20.71% drop in mean elastic varus bending stiffness. Removal of the two inferomedial screw above it resulted in a larger drop. The proximal screw pair had the largest contribution to extension and flexion bending stiffness. Varus stiffness of S3 plate constructs was higher than PHILOS and Fx plate constructs. Stability of humeri treated with S3 plate depends on screws' number, orientation and location. Varus stiffness of S3 plate construct (10.54 N/mm) was higher than that of PHILOS (6.61 N/mm) and Fx (7.59 N/mm) plate constructs. We attribute this to S3 plates' thicker cross section, the 135° inclination of its screws with respect to the humeral shaft and the availability of pegs for subchondral support.
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Affiliation(s)
- Ali Jabran
- 1 School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester, UK
| | - Chris Peach
- 1 School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester, UK.,2 Department of Shoulder and Elbow Surgery, University Hospital of South Manchester, Manchester, UK
| | - Zhenmin Zou
- 1 School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester, UK
| | - Lei Ren
- 1 School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Manchester, UK
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Effect of screw thread length on stiffness of proximal humerus locking plate constructs: A finite element study. Med Eng Phys 2018; 63:79-87. [PMID: 30554981 DOI: 10.1016/j.medengphy.2018.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 11/03/2018] [Accepted: 12/04/2018] [Indexed: 11/21/2022]
Abstract
Plate-based treatment of proximal humerus fractures is associated with a high risk of complications such as screw perforation into glenohumeral joint. Smooth and threaded pegs were developed with the hope of minimising these risks. No consensus exists onto which threading profile achieves stiffest bone-plate construct. This study investigated the biomechanical effect of five percentages of threading on individual humeral head screws on a bone-plate construct. A finite element model simulating a two-part proximal humerus fracture treated with a Spatial Subchondral Support plate was developed and validated against in vitro biomechanical tests. The proportion of the humeral head screw length that was threaded was varied between 0%-100% in 25% increments. A 5-mm cantilever varus displacement was applied and the required load (F5) was calculated. Full (100%) threading achieved the stiffest construct for all six screws. Fully threading all smooth pegs at once increased F5 by 18%. Threading did not increase F5 equally in all screws. Inferior three plate screws exhibited a larger increase in stiffness than superior three. Most of the mechanical benefits of threading in inferior three screws can be achieved by using threaded pegs (50% threading) while the superior three screws need to be fully threaded. In practice, the smooth surface profile may also offer additional mechanical benefits if implanted with longer lengths and larger diameters. Threading is an effective way of increasing the varus bending stiffness of proximal humerus plates constructs.
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Padolino A, Porcellini G, Guollo B, Fabbri E, Kiran Kumar GN, Paladini P, Merolla G. Comparison of CFR-PEEK and conventional titanium locking plates for proximal humeral fractures: a retrospective controlled study of patient outcomes. Musculoskelet Surg 2018; 102:49-56. [PMID: 30343471 DOI: 10.1007/s12306-018-0562-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 08/05/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND Metal plates are the fixation devices used most frequently to proximal humeral fractures (PHFs). However, in recent years carbon fiber-reinforced polyetheretherketone (CFR-PEEK) plates have become increasingly common. This study compares the clinical and radiographic outcomes of 42 Neer three- and four-part PHFs treated with CFR-PEEK or metal (titanium) plates. MATERIALS AND METHODS Forty-two PHF patients were managed with CFR-PEEK plates (n = 21, males/females 9/12; mean age 57.4 years; mean follow-up 30.7 months; CFR-PEEK group) or metal plates (n = 21; males/females 7/14; mean age 55.8 years; mean follow-up 52.7 months; Metal group). Active shoulder mobility (anterior elevation, lateral elevation, external rotation, and internal rotation), the Constant-Murley Score, the Simple Shoulder Test Score, and the pain score were recorded. Preoperative computed tomography scans and X-rays were obtained. Postoperative fracture healing and displacement, tuberosity resorption and/or malposition, hardware position, and cortical thinning (CT) under the plate were assessed radiographically. RESULTS Shoulder mobility, clinical, and pain scores were similar in both patient groups. CT was significantly greater in CFR-PEEK patients (mean difference, 1.14 mm; p = 0.0003). In both groups, incomplete or poor calcar reduction was associated to a significantly higher complication rate, especially stiffness and muscle weakness (p = 0.016). The rate of tuberosity resorption was significantly higher in the Metal group (p = 0.040). Two patients required revision to a hemiarthroplasty (CFR-PEEK) and reverse arthroplasty (Metal group). CONCLUSIONS CFR-PEEK plates provide a viable alternative to conventional titanium plates in PHFs, ensuring similar clinical outcomes and a lower rate of tuberosity resorption, but they involve higher stress shielding under the plate.
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Affiliation(s)
- A Padolino
- Shoulder and Elbow Unit, Cervesi Hospital, Cattolica - AUSL della Romagna, Ambito Territoriale di Rimini, Cattolica, Italy
| | - G Porcellini
- Shoulder and Elbow Unit, Cervesi Hospital, Cattolica - AUSL della Romagna, Ambito Territoriale di Rimini, Cattolica, Italy
| | - B Guollo
- Shoulder and Elbow Unit, Cervesi Hospital, Cattolica - AUSL della Romagna, Ambito Territoriale di Rimini, Cattolica, Italy
| | - E Fabbri
- Research and Innovation Department - AUSL della Romagna, Ambito Territoriale di Rimini, Rimini, Italy
| | - G N Kiran Kumar
- Shoulder and Elbow Unit, Cervesi Hospital, Cattolica - AUSL della Romagna, Ambito Territoriale di Rimini, Cattolica, Italy
| | - P Paladini
- Shoulder and Elbow Unit, Cervesi Hospital, Cattolica - AUSL della Romagna, Ambito Territoriale di Rimini, Cattolica, Italy
| | - G Merolla
- Shoulder and Elbow Unit, Cervesi Hospital, Cattolica - AUSL della Romagna, Ambito Territoriale di Rimini, Cattolica, Italy.
- Biomechanics Laboratory, Cervesi Hospital, Cattolica - AUSL della Romagna, Ambito Territoriale di Rimini, Cattolica, Italy.
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Biomechanical Comparison of 3 Inferiorly Directed Versus 3 Superiorly Directed Locking Screws on Stability in a 3-Part Proximal Humerus Fracture Model. J Orthop Trauma 2018; 32:306-312. [PMID: 29401089 DOI: 10.1097/bot.0000000000001112] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To quantify the stability of 3 points of inferiorly directed versus 3 points of superiorly directed locking screw fixation compared with the full contingent of 6 points of locked screw fixation in the treatment of a 3-part proximal humerus fracture. METHODS A standardized 3-part fracture was created in 10 matched pairs (experimental groups) and 10 nonmatched humeri (control group). Osteosynthesis was performed using 3 locking screws in the superior hemisphere of the humeral head (suspension), 3 locking screws in the inferior hemisphere (buttress), or the full complement of 6 locking screws (control). Specimens were tested in varus cantilever bending (7.5 Nm) to 10,000 cycles or failure. Construct survival (%) and the cycles to failure were compared. RESULTS Seven of 10 controls survived the 10,000-cycle runout (70%: 8193 average cycles to failure). No experimental constructs survived the 10,000-cycle runout. Suspension and buttress screw groups failed an average of 331 and 516 cycles, respectively (P = 1.00). The average number of cycles to failure and the number of humeri surviving the 10,000-cycle runout were greater in the control group than in the experimental groups (P ≤ 0.006). CONCLUSION Data support the use of a full contingent of 6 points of locking screw fixation over 3 superior or 3 inferior points of fixation in the treatment of a 3-part proximal humerus fracture with a locking construct. No biomechanical advantage to the 3 buttress or 3 suspension screws used in isolation was observed.
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Biomechanical analysis of plate systems for proximal humerus fractures: a systematic literature review. Biomed Eng Online 2018; 17:47. [PMID: 29703261 PMCID: PMC5923007 DOI: 10.1186/s12938-018-0479-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 04/18/2018] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Proximal humerus fractures are the third most common in the human body but their management remains controversial. Open reduction and internal fixation with plates is one of the leading modes of operative treatment for these fractures. The development of technologies and techniques for these plates, during the recent decades, promise a bright future for their clinical use. A comprehensive review of in vitro biomechanical studies is needed for the comparison of plates' mechanical performance and the testing methodologies. This will not only guide clinicians with plate selection but also with the design of future in vitro biomechanical studies. This review was aimed to systematically categorise and review the in vitro biomechanical studies of these plates based on their protocols and discuss their results. The technologies and techniques investigated in these studies were categorised and compared to reach a census where possible. METHODS AND RESULTS Web of Science and Scopus database search yielded 62 studies. Out of these, 51 performed axial loading, torsion, bending and/or combined bending and axial loading while 11 simulated complex glenohumeral movements by using tendons. Loading conditions and set-up, failure criteria and performance parameters, as well as results for each study, were reviewed. Only two studies tested four-part fracture model while the rest investigated two- and three-part fractures. In ten studies, synthetic humeri were tested instead of cadaveric ones. In addition to load-displacement data, three-dimensional motion analysis systems, digital image correlation and acoustic emission testing have been used for measurement. CONCLUSIONS Overall, PHILOS was the most tested plate and locking plates demonstrated better mechanical performance than non-locking ones. Conflicting results have been published for their comparison with non-locking blade plates and polyaxial locking screws. Augmentation with cement [calcium phosphate or poly(methyl methacrylate)] or allografts (fibular and femoral head) was found to improve bone-plate constructs' mechanical performance. Controversy still lies over the use of rigid and semi-rigid implants and the insertion of inferomedial screws for calcar region support. This review will guide the design of in vitro and in silico biomechanical tests and also supplement the study of clinical literature.
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11
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Jabran A, Peach C, Zou Z, Ren L. Hybrid blade and locking plate fixation for proximal humerus fractures: a comparative biomechanical analysis. Biomed Eng Online 2018; 17:10. [PMID: 29370867 PMCID: PMC5785900 DOI: 10.1186/s12938-018-0447-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 01/17/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Open reduction and internal fixation of proximal humerus fractures can be difficult to achieve adequate, complication free results due to osteopenia of the proximal humerus and unstable fracture patterns. This study aimed to compare the biomechanical properties of a novel hybrid fixed angle blade plate (Fx plate) with an established fixed angle locking plate (PHILOS plate). METHODS A two-part fracture was simulated in synthetic composite humeri by creating a transverse osteotomy and 10 mm fracture gap at the surgical neck. After treating the fractures with either an Fx plate or a PHILOS plate, humeral head was fixed and the shaft was displaced in a cantilever fashion. For elastic tests, loading was along the frontal and sagittal plane to achieve varus/valgus and extension/flexion, respectively. In plastic tests, loading was in a varus direction to determine the constructs' resistance to varus collapse. RESULTS In elastic tests, both construct types had higher peak load and stiffness in extension/flexion than varus/valgus. Fx plate constructs were significantly stiffer than PHILOS constructs in varus/valgus (mean: 7.590/6.900 vs. 6.609/6.091 N/mm; p < 0.001 for both) but significantly less stiff in extension/flexion (8.770/9.541 vs. 9.533/9.997 N/mm; p < 0.001 for extension, p < 0.05 for flexion). In varus plastic tests, significantly higher peak loads were reported for Fx plate than PHILOS (134.391 vs. 115.531 N; p < 0.001). CONCLUSIONS In this fracture gap model, humeri implanted with a novel Fx plate provided higher varus/valgus stiffness but lower extension/flexion stiffness than a more traditional proximal humeral locking plate design (PHILOS).
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Affiliation(s)
- Ali Jabran
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, Manchester, M13 9PL, UK
| | - Chris Peach
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, Manchester, M13 9PL, UK.,Department of Shoulder and Elbow Surgery, University Hospital of South Manchester, Southmoor Road, Wythenshawe, Manchester, M23 9LT, UK
| | - Zhenmin Zou
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, Manchester, M13 9PL, UK
| | - Lei Ren
- School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, Manchester, M13 9PL, UK.
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Biomechanical Contribution of Tension-Reducing Rotator Cuff Sutures in 3-Part Proximal Humerus Fractures. J Orthop Trauma 2016; 30:e262-6. [PMID: 26978137 DOI: 10.1097/bot.0000000000000575] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Using a cadaveric 3-part fracture model and cyclic loading protocol, our study objectives were to quantify the stabilizing effect of tension-reducing rotator cuff sutures in terms of fracture displacement across the surgical neck and greater tuberosity compared with a control group in which no sutures were used. METHODS Six matched pairs of fresh frozen specimens underwent a standardized, 3-part, proximal humerus fracture and were split into 2 groups. The control group had the fracture fixed with a plate and screw construct only while the experimental group had additional suture fixation through the plate to each rotator cuff tendon. Active abduction through the rotator cuff was simulated for 100, 200, 300, and 400 cycles and to failure at 1000 N. A Mann-Whitney U test compared cyclic displacement of the greater tuberosity and surgical neck fracture gaps and load to failure between the 2 groups. RESULTS There was no significant difference (P > 0.05) in fracture gap between fixation methods at the surgical neck at 100 (P = 0.13), 200 (P = 0.07), 300 (P = 0.49), and 400 (P = 0.07) cycles. There was no significant difference (P > 0.05) between fixation methods in the fracture gap at the greater tuberosity at 100 (P = 0.39), 200 (P = 1.00), 300 (P = 0.31), and 400 (P = 0.59) cycles. There was no significant difference (P > 0.5) at 1000 N at the surgical neck (P = 0.70) or the greater tuberosity (P = 0.39). CONCLUSIONS Tension-relieving rotator cuff sutures do not add stability to the repair of 3-part proximal humerus fractures. Varus collapse and greater tuberosity displacement are common complications associated with 3-part fractures. No mechanical data exist to demonstrate benefit of adding suture to a plate and screw construct for limiting fracture displacement.
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Biomechanical and range of motion analysis of two proximally fixed locking plate systems for fixation of proximal humeral fractures. CURRENT ORTHOPAEDIC PRACTICE 2015. [DOI: 10.1097/bco.0000000000000202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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No Contribution of Tension-Reducing Rotator Cuff Sutures on Locking Plate Fixation in a 2-Part Proximal Humerus Fracture Model. J Orthop Trauma 2014; 28:458-63. [PMID: 24375272 DOI: 10.1097/bot.0000000000000051] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Varus failure is a well-known complication of open reduction internal fixation of proximal humeral fractures. The addition of tension-reducing sutures from the plate to the rotator cuff may attenuate the deforming forces of the rotator cuff resulting in decreased varus failure. In this study, we investigate the biomechanical contributions of tension-reducing sutures to a locked plate construct in a 2-part proximal humerus fracture model. METHODS Two fixation techniques were tested in 12 matched fresh frozen humeri in which standard 2-part fractures of the surgical neck were created with a gap simulating surgical neck medial comminution. In group 1, fractures were fixed with a standard proximal humerus locking plate. In group 2, the plate fixation was similar, and additionally, tension-reducing sutures were applied from the plate to the rotator cuff. Active abduction was simulated for 400 cycles with force applied through the rotator cuff tendons. Intercyclic fracture motion, change in displacement, and load to failure were recorded. RESULTS The addition of tension-reducing sutures did not lead to significant differences in intercyclic fracture motion. The mean change in displacement and load to failure were similar in both groups. Failure typically occurred in both groups at the rotator cuff testing clamp interface. CONCLUSIONS Tension-relieving rotator cuff sutures added to locking plate fixation did not lead to a change in fracture gap with cyclic loading or an increase in ultimate failure load in a 2-part surgical neck proximal humerus fracture model without medial support.
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Yoon RS, Dziadosz D, Porter DA, Frank MA, Smith WR, Liporace FA. A comprehensive update on current fixation options for two-part proximal humerus fractures: a biomechanical investigation. Injury 2014; 45:510-4. [PMID: 24168862 DOI: 10.1016/j.injury.2013.08.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 08/29/2013] [Indexed: 02/02/2023]
Abstract
BACKGROUND Recent advancements in implant technology offer updated options for surgical management that have been rapidly adopted into clinical practice. The objective of this study is to biomechanically test and compare the current fixation options available for surgical fixation of two-part proximal humerus fractures and establish load to failure and stiffness values. METHODS Sixteen match-paired (32 total) fresh-frozen, cadaveric specimens were randomized to receive 1 of 4 fixation constructs following creation of an AO/OTA Type 11A3 (two-part) proximal humerus fractures. Fixation constructs tested consisted of 3.5 mm fixed angle plate (3.5-FAP), 4.5 mm fixed angle plate (4.5-FAP), humeral intramedullary nail (IMN), and a humeral intramedullary nail with a fixed angle blade (IMN-FAB). Specimen bone density was measured to ensure no adequate, non-osteoporotic bone. Constructs were tested for stiffness and ultimate load to failure and compared via one-way ANOVA analysis with subsequent post hoc Tukey HSD multiple group comparison statistical analysis. RESULTS The IMN-FAB construct was significantly stiffer than the 3.5-FAP construct (123.8 vs. 23.9, p<0.0001), the 4.5-FAP construct (123.8 vs. 33.3, p<0.0001) and the IMN construct (123.8 vs. 60.1, p=0.005). The IMN-FAB construct reported a significantly higher load to failure than the 3.5-FAB construct (4667.3 N vs. 1756.9 N, p<0.0001), and the 4.5-FAP construct (4667.3 N vs. 2829.4 N, p=0.019, Table 2). The IMN construct had a significantly higher load to failure than the 3.5-FAP construct (3946.8 vs. 1756.9, p=0.001, Table 2). CONCLUSION Biomechanical testing of modern fixation options for two-part proximal humerus fracture exhibited that the stiffest and highest load to failure construct was the IMN-FAB followed by the IMN, 3.5-FAP and then the 4.5-FAP constructs. However, prospective clinical trials with longer-term follow-up are required for definitive assessment of the ideal fixation construct for surgical management of two-part proximal humerus fractures.
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Affiliation(s)
- Richard S Yoon
- Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY 10003, USA
| | - Daniel Dziadosz
- Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, INOVA Fairfax Hospital, Faiefax, VA 22003, USA
| | - David A Porter
- Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, INOVA Fairfax Hospital, Faiefax, VA 22003, USA
| | - Matthew A Frank
- Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, INOVA Fairfax Hospital, Faiefax, VA 22003, USA
| | - Wade R Smith
- Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, Swedish Medical Center, Denver, CO 80204, USA
| | - Frank A Liporace
- Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY 10003, USA.
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