Augmentation of plate osteosynthesis for proximal humeral fractures: a systematic review of current biomechanical and clinical studies

Intramedullary versus locking plate fixation for proximal humerus fractures: indications and technical considerations

Background

The incidence of proximal humerus fractures (PHFs) continues to increase with an aging population, and intramedullary nailing (IMN) and locking plate fixation are two commonly employed techniques for the surgical management of PHF. However, the optimal fixation method can be a source of ongoing controversy. Some influencing factors include the extent of humeral head involvement, fracture complexity, patient age, and surgeon preference. There are many studies that provide a mix of data either when comparing the two techniques or analyzing them in isolation. The aim of this review is to further elucidate the indications and technical considerations involved specifically in IMN vs. locking plate fixation for PHF to further aid orthopedic surgeons when choosing surgical management.

Methods

A narrative approach was chosen for this review allowing for a comprehensive review of literature, including recent findings pertaining to the comparison of management options for PHF. A comprehensive literature search was conducted using the PubMed, Embase, and Cochrane Library databases. The inclusion criteria involved studies that discussed "proximal humerus fracture" and either "intramedullary nail" or "locking plate fixation."

Results

Complications such as avascular necrosis, hardware failure, additional surgical interventions, infection, fracture redisplacement, rotator cuff rupture, and nonunion did not show significant differences between the two groups. Newer generation humeral nails have minimized early complications. As both techniques undergo further refinement and utilization when specifically indicated, functional outcomes, potential complications, and postoperative pain continue to be improved.

Conclusion

The available evidence suggests that both intramedullary nails and locking plates can effectively restore shoulder function in the treatment of displaced proximal humeral fractures, with unclear superiority of either method. The choice of technique should be tailored to patient factors such as fracture type, age, bone quality, and functional expectations. Surgeon experience also plays a role. While certain presentations may exhibit trends that favor one fixation, no specific technique can be universally recommended. Both IMN and LP have shown comparable and satisfactory outcomes, and the final fixation method chosen should take into account the unique characteristics of each patient.

Finite element analysis and biomechanical study of "sandwich" fixation in the treatment of elderly proximal humerus fractures

Proximal humerus fractures (PHFs) are common in the elderly and usually involve defects in the medial column.The current standard for medial column reconstruction is a lateral locking plate (LLP) in combination with either an intramedullary fibula support or an autogenous fibula graft. However, autogenous fibula graft can lead to additional trauma for patients and allogeneic fibular graft can increase patients' economic burden and pose risks of infection and disease transmission. The primary objective of this study was to introduce and assess a novel "Sandwich" fixation technique and compare its biomechanical properties to the traditional fixation methods for PHFs. In this study, we established finite element models of two different internal fixation methods: LLP-intramedullary reconstruction plate with bone cement (LLP-IRPBC) and LLP-intramedullary fibula segment (LLP-IFS). The biomechanical properties of the two fixation methods were evaluated by applying axial, adduction, abduction, torsional loads and screw extraction tests to the models. These FEA results were subsequently validated through a series of biomechanical experiments. Under various loading conditions such as axial, adduction, abduction, and rotation, the LLP-IRPBC group consistently demonstrated higher structural stiffness and less displacement compared to the LLP-IFS group, regardless of whether the bone was in a normal (Nor) or osteoporotic (Ost) state. Under axial, abduction and torsional loads, the maximum stress on LLPs of LLP-IRPBC group was lower than that of LLP-IFS group, while under adduction load, the maximum stress on LLPs of LLP-IRPBC group was higher than that of LLP-IFS group under Ost condition, and almost the same under Nor condition. The screw-pulling force in the LLP-IRPBC group was 1.85 times greater than that of the LLP-IFS group in Nor conditions and 1.36 times greater in Ost conditions. Importantly, the results of the biomechanical experiments closely mirrored those obtained through FEA, confirming the accuracy and reliability of FEA. The novel "Sandwich" fixation technique appears to offer stable medial support and rotational stability while significantly enhancing the strength of the fixation screws. This innovative approach represents a promising strategy for clinical treatment of PHFs.

Augmented versus non-augmented locking-plate fixation in proximal humeral fractures

Aims

Proximal humeral fractures are the third most common fracture among the elderly. Complications associated with fixation include screw perforation, varus collapse, and avascular necrosis of the humeral head. To address these challenges, various augmentation techniques to increase medial column support have been developed. There are currently no recent studies that definitively establish the superiority of augmented fixation over non-augmented implants in the surgical treatment of proximal humeral fractures. The aim of this systematic review and meta-analysis was to compare the outcomes of patients who underwent locking-plate fixation with cement augmentation or bone-graft augmentation versus those who underwent locking-plate fixation without augmentation for proximal humeral fractures.

Methods

The search was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Articles involving patients with complex proximal humeral fractures treated using open reduction with locking-plate fixation, with or without augmentation, were considered. A meta-analysis of comparative studies comparing locking-plate fixation with cement augmentation or with bone-graft augmentation versus locking-plate fixation without augmentation was performed.

Results

A total of 19 studies were included in the qualitative synthesis, and six comparative studies were included in the meta-analysis. Overall, 120 patients received locking-plate fixation with bone-graft augmentation, 179 patients received locking-plate fixation with cement augmentation, and 336 patients received locking-plate fixation without augmentation. No statistically relevant differences between the augmented and non-augmented cohorts were found in terms of the Disabilities of the Arm, Shoulder and Hand questionnaire score and Constant-Murley Score. The cement-augmented group had a significantly lower rate of complications compared to the non-augmented group.

Conclusion

While locking-plate fixation with cement augmentation appears to produce a lower complication rate compared to locking-plate fixation alone, functional outcomes seem comparable between augmented and non-augmented techniques.

[Augmentation techniques for the treatment of osteoporosis-associated fractures of the extremities]

The current demographic development is leading to an increasing number of cases of osteoporosis-related fractures. Affected individuals are typically part of a vulnerable, predominantly geriatric patient group with limited physical resources. Additionally, the pathophysiological characteristics of osteoporotic bones with reduced bone quality and quantity, pose a significant challenge to the osteosynthesis techniques used. Achieving rapid postoperative mobilization and stable weight-bearing osteosynthesis to prevent postoperative medical complications are the main goals of the surgical management. In recent years augmentation techniques have gained in importance in the treatment of osteoporosis-related fractures by significantly enhancing the stability of osteosyntheses and reducing mechanical complication rates. The main options available are polymethyl methacrylate (PMMA) augmentation and various bioresorbable bone substitute materials with different properties. Implant augmentations can be applied at various locations in the extremity bones and standardized procedures are now available, such as for the proximal humerus and femur. When used correctly, low complication rates and promising clinical outcomes are observed. This article aims to provide an overview of available techniques and applications based on the current literature. Guidelines and substantial scientific evidence are still limited.

Treatment of Metaphyseal Defects in Plated Proximal Humerus Fractures with a New Augmentation Technique-A Biomechanical Cadaveric Study

Background and Objectives: Unstable proximal humerus fractures (PHFs) with metaphyseal defects-weakening the osteosynthesis construct-are challenging to treat. A new augmentation technique of plated complex PHFs with metaphyseal defects was recently introduced in the clinical practice. This biomechanical study aimed to analyze the stability of plated unstable PHFs augmented via implementation of this technique versus no augmentation. Materials and Methods: Three-part AO/OTA 11-B1.1 unstable PHFs with metaphyseal defects were created in sixteen paired human cadaveric humeri (average donor age 76 years, range 66-92 years), pairwise assigned to two groups for locked plate fixation with identical implant configuration. In one of the groups, six-milliliter polymethylmethacrylate bone cement with medium viscosity (seven minutes after mixing) was placed manually through the lateral window in the defect of the humerus head after its anatomical reduction to the shaft and prior to the anatomical reduction of the greater tuberosity fragment. All specimens were tested biomechanically in a 25° adduction, applying progressively increasing cyclic loading at 2 Hz until failure. Interfragmentary movements were monitored by motion tracking and X-ray imaging. Results: Initial stiffness was not significantly different between the groups, p = 0.467. Varus deformation of the humerus head fragment, fracture displacement at the medial humerus head aspect, and proximal screw migration and cut-out were significantly smaller in the augmented group after 2000, 4000, 6000, 8000 and 10,000 cycles, p ≤ 0.019. Cycles to 5° varus deformation of the humerus head fragment-set as a clinically relevant failure criterion-and failure load were significantly higher in the augmented group, p = 0.018. Conclusions: From a biomechanical standpoint, augmentation with polymethylmethacrylate bone cement placed in the metaphyseal humerus head defect of plated unstable PHFs considerably enhances fixation stability and can reduce the risk of postoperative complications.

Proximal humerus fractures: A review of current practice

The management of proximal humeral fractures (PHF) remains controversial. Its incidence is increasing. Patients should be meticulously assessed clinically for co-morbidities and neuro-vascular injuries. Radiological investigation helps provide information on the fracture configuration and dislocations. Enhanced by 3-dimensional CT scanning, these further help in decision making and operative planning. PHF classifications have been demonstrated to have poor intra-observer and inter-observer reliability. Research has identified some radiographic predictive factors for humeral head ischaemia and likely failure of surgical fixation. The range of management options include non-operative treatment, operative fixation, intramedullary nailing and arthroplasty (hemiarthroplasty, reverse shoulder replacement). The majority of PHFs are stable injuries and non-operative management is usually successful. Some degree of malunion is readily tolerated especially by elderly patients. Surgical management of significantly displaced, unstable proximal humerus fractures should aim to stabilise the fracture adequately and provide satisfactory function for the long term. Management of the greater tuberosity is pivotal for the eventual outcome. When fixation may appear to be compromised by poor bone quality, likely poor function, age related rotator cuff degeneration or likely humeral head ischaemia clinicians may opt for arthroplasty. Successful hemiarthroplasty outcomes are dependent on sufficient healing of the tuberosity and recovery of the rotator cuff integrity. Reverse shoulder replacement can predictably deliver good functional outcomes for the shoulder in elderly patients, where rotator cuff dysfunction is suspected or as a revision procedure following failure of other surgical interventions. As opposed to hemiarthroplasty, which has shown a downward trend, there has been an increasing trend towards the use of reverse shoulder replacement in proximal humeral fractures. The management of PHFs should be patient specific, fracture specific and meet the functional demands and needs of the individual patient. The surgeon's skill set and clinical experience also plays an important role in the options of management available.

Surgical outcome of avulsion fractures of the distal fibula: a systematic literature review

PURPOSE

To provide a systematic overview of clinical and radiographic outcomes in patients who underwent surgical treatment of a painful avulsion fragment of the distal fibula also known as posttraumatic os subfibulare.

METHODS

A systematic literature search across two major sources (PubMed and Scopus) was performed. Twenty-seven studies were included and analyzed using the modified Coleman score to assess the methodologic quality.

RESULTS

The surgical treatment of symptomatic os subfibulare, with or without concomitant ankle instability, generally results in substantial improvement in clinical and radiographic outcomes with relative low complication rates. Clinical outcome measures may not be affected by the presence of ankle instability or by the fragment size. The methodological quality of analyzed studies was satisfactory.

CONCLUSION

Posttraumatic os subfibulare may result in chronic pain and ankle instability. If surgery is indicated, ankle instability should be concomitantly addressed when present. Based on available literature, satisfactory postoperative outcomes can be reliably expected following surgical treatment.

LEVEL OF EVIDENCE

Systematic Review of Level III and Level IV Studies, Level IV.

Treatment Reality of Proximal Humeral Fractures in the Elderly-Trending Variants of Locking Plate Fixation in Germany

BACKGROUND

The surgical treatment of proximal humeral fractures (PHFs) with locking plate fixation (LPF) in the elderly is associated with high complication rates, especially in osteoporotic bone. Variants of LPF such as additional cerclages, double plating, bone grafting and cement augmentation can be applied. The objective of the study was to describe the extent of their actual use and how this changed over time.

METHODS

Retrospective analysis of health claims data of the Federal Association of the Local Health Insurance Funds was performed, covering all patients aged 65 years and older, who had a coded diagnosis of PHF and were treated with LPF between 2010 and 2018. Differences between treatment variants were analyzed (explorative) via chi-squared or Kruskal-Wallis tests.

RESULTS

Of the 41,216 treated patients, 32,952 (80%) were treated with LPF only, 5572 (14%) received additional screws or plates, 1983 (5%) received additional augmentations and 709 (2%) received a combination of both. During the study period, relative changes were observed as follows: -35% for LPF only, +58% for LPF with additional fracture fixation and +25% for LPF with additional augmentation. Overall, the intra-hospital complication rate was 15% with differences between the treatment variants (LPF only 15%, LPF with additional fracture fixation 14%, LPF with additional augmentation 19%; p < 0.001), and a 30-day mortality of 2%.

CONCLUSIONS

Within an overall decrease of LPF by approximately one-third, there is both an absolute and relative increase of treatment variants. Collectively, they account for 20% of all coded LPFs, which might indicate more personalized treatment pathways. The leading variant was additional fracture fixation using cerclages.

Continuous Shoulder Activity Tracking after Open Reduction and Internal Fixation of Proximal Humerus Fractures

Postoperative shoulder activity after proximal humerus fracture treatment could influence the outcomes of osteosynthesis and may depend on the rehabilitation protocol. This multi-centric prospective study aimed at evaluating the feasibility of continuous shoulder activity monitoring over the first six postoperative weeks, investigating potential differences between two different rehabilitation protocols. Shoulder activity was assessed with pairs of accelerometer-based trackers during the first six postoperative weeks in thirteen elderly patients having a complex proximal humerus fracture treated with a locking plate. Shoulder angles and elevation events were evaluated over time and compared between the two centers utilizing different standard rehabilitation protocols. The overall mean shoulder angle ranged from 11° to 23°, and the number of daily elevation events was between 547 and 5756. Average angles showed longitudinal change <5° over 31 ± 10 days. The number of events increased by 300% on average. Results of the two clinics exhibited no characteristic differences for shoulder angle, but the number of events increased only for the site utilizing immediate mobilization. In addition to considerable inter-patient variation, not the mean shoulder angle but the number of elevations events increased markedly over time. Differences between the two sites in number of daily events may be associated with the different rehabilitation protocols.

Feasibility and Radiological Outcome of Minimally Invasive Locked Plating of Proximal Humeral Fractures in Geriatric Patients

BACKGROUND

Proximal humerus fractures are common injuries in the elderly. Locked plating showed high complication and reoperation rates at first. However, with second-generation implants and augmentation, minimally invasive locked plating might be a viable alternative to arthroplasty or conservative treatment.

MATERIAL AND METHODS

A retrospective chart review was performed for all patients with proximal humerus fractures treated between 2014 and 2020 with locked plating. All patients over 60 years of age who underwent surgery for a proximal humerus fracture with plate osteosynthesis (NCB, Philos, or Philos with cement) during the specified period were included. Pathological fractures, intramedullary nailing, or arthroplasty were excluded. Primary outcome measurements included secondary displacement and surgical complications. Secondary outcomes comprised function and mortality within one year.

RESULTS

A total of 249 patients (mean age 75.6 +/- 8.9 years; 194 women and 55 men) were included in the study. No significant difference in the AO fracture classification could be found. Ninety-two patients were surgically treated with first-generation locked plating (NCB, Zimmer Biomet, Wayne Township, IN, USA), 113 patients with second-generation locked plating (Philos, Depuy Synthes, Wayne Township, IN, USA), and 44 patients with cement-augmented second-generation locked plating (Philos, Traumacem V+, Depuy Synthes). A 6-week radiological follow-up was completed for 189 patients. In all groups, X-rays were performed one day after surgery, and these showed no differences concerning the head shaft angle between the groups. The mean secondary varus dislocation (decrease of the head shaft angle) after six weeks for first-generation locked plating was 6.6 ± 12° (n = 72), for second-generation locked plating 4.4 ± 6.5 (n = 83), and for second-generation with augmentation 1.9 ± 3.7 (n = 35) with a significant difference between the groups (p = 0.012). Logistic regression showed a significant dependency for secondary dislocation for the type of treatment (p = 0.038), age (p = 0.01), and preoperative varus fracture displacement (p = 0.033). Significantly fewer surgical complications have been observed in the augmented second-generation locked plating group (NCB: 26.3%; Philos 21.5%; Philos-augmented 8.6%; p = 0.015). Range of motion was documented in 122 out of 209 patients after 3 months. In the Philos-augmented group, 50% of the patients achieved at least 90° anteversion and abduction, which was only about a third of the patients in the other 2 groups (NCB 34.8%, n = 46; Philos 35.8%, n = 56; augmented-Philos 50.0%, n = 20; p = 0.429).

CONCLUSION

Minimally invasive locked plating is still a valuable treatment option for geriatric patients. With augmentation and modern implants, the complication rate is low and comparable to those of reverse shoulder arthroplasty reported in the literature, even in the challenging group of elderly patients.

Role of Fibular Allograft in Proximal Humerus Fractures: A Systematic Review

OBJECTIVES

To analyze the outcomes and complication rates of fibular allografts (FA) as an augmentation technique for proximal humeral fractures and determine their appropriate indications.

DATA SOURCES

English- and Spanish-language articles in PubMed, MEDLINE, Embase, Web of Science (Core Collection), and Google Scholar databases were systematically reviewed with the Preferred Reporting Items for Systematic Reviews guidelines on April 10, 2020.

STUDY SELECTION

Studies of patients with proximal humeral fractures treated primarily with FA and locking compression plates and with a minimum follow-up of 6 months were included, and presenting results with standardized clinical scales, radiological values, and operative complications.

DATA EXTRACTION

Two authors independently extracted data from the selected studies with a standardized data collection form. Subsequently, each extracted data set was consolidated on the agreement of authors.

DATA SYNTHESIS

From the initial screening of 361 articles, 5 case series and 6 retrospective cohort studies were included. A meta-analysis was not performed.

CONCLUSIONS

FA improved the clinical and radiological results, thereby reducing complications. The optimal indication for this procedure may be a 4-part fracture with medial column disruption in younger adults.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Proximal humeral fractures treated with a low-profile plate with enhanced fixation properties

BACKGROUND

Our purpose was to evaluate the clinical and radiographic outcomes of proximal humeral fractures treated with a new generation plating system and compare results with a meta-analysis of recent literature.

METHODS

Between 2014 and 2017, 93 patients (18 males, 75 females) with proximal humerus fractures were treated with open reduction and internal fixation (ORIF) using a Pantera® Plate. These low-profile plates are anatomically shaped and include "cross-elements" that form a three-dimensional scaffold in bone to enhance fixation stability. According to Neer classification, there were 24 two-part fractures, 49 three-part fractures and 20 four-part fractures (4 with dislocated heads). X-rays and Constant Shoulder Scores (CSS) were used to evaluate healing, complications, and clinical outcomes. Results were compared with a meta-analysis of similar studies reported in literature over the last 10 years.

RESULTS

Eighty-three patients with a minimum follow-up of 2 years had a mean CSS of 72 (53-90) graded as excellent for 23 patients (28%), good for 35 (42%), fair for 14 (17%), and poor for 11 (13%). Fractures healed without complication in 75 (91%) patients. Eight (9%) complications were observed, i.e., three avascular necrosis of the humeral head, one case of implant loosening, two cases of subacromial impingement and two superficial infections. There was no significant correlation between Neer fracture stage and patient outcome (p = 0.257). Compared to the literature, this method had a lower complication grade (p = 0.03), though it did not significantly differ in its clinical outcomes (p = 0.08).

CONCLUSIONS

The investigated plating system includes design features that can potentially increase utility for ORIF of proximal humeral fractures. While the complication profile was signficantly less than reported in the literature for standard proximal humerus plates, clinical outcomes were similar. Further studies will be required to better understand the role of plate design on treatment of these challenging fractures.

LEVEL OF EVIDENCE

IV, therapeutic study.

Effects of fibular strut augmentation for the open reduction and internal fixation of proximal humeral fractures: a systematic review and meta-analysis

BACKGROUND

There is still a lack of remarkable consensus regarding the clinical efficacy of the application of fibular strut augmentation (FSA) combined with a locking plate for proximal humeral fractures. A systematic review and meta-analysis to assess the effect of the use of FSAs in open reduction and internal fixation of proximal humeral fractures was conducted.

METHODS

A literature search was conducted in PubMed, Embase, Cochrane, Web of Science Core Collection, and ClinicalTrials.gov to identify trials that compared the clinical outcomes of proximal humeral fractures treated using a locking plate with or without FSA. The primary outcome measures were postoperative complications, radiographical findings, functional recovery scores, and postoperative range of motion (ROM). Data were pooled and analysed using a random-effects model based on the Der Simonian and Laird method.

RESULTS

Eight studies involving 596 participants were included for further analysis. Compared with using a locking plate independently, the additional application of FSA was associated with the likelihood of lower risk of overall complications (OR 0.37; 95% CI 0.22-0.65; I² = 12.22%; 95% PI 0.14-0.98) and the rate of patients with orthopaedic complications (OR 0.48; 95% CI 0.25-0.92; I² = 7.52%; 95% PI 0.16-1.45), less changes in postoperative humeral head height (MD - 2.40; 95% CI - 2.49 to - 2.31; I² = 0.00%; 95% PI - 2.61 to - 2.20) and the neck-shaft angle (MD - 6.30; 95% CI - 7.23 to - 5.36; I² = 79.32%; 95% PI - 10.06 to - 2.53), superior functional outcomes (Constant-Murley score: MD 5.07; 95% CI 3.40 to 6.74; I² = 0.00%; 95% PI 2.361-7.78; American Shoulder and Elbow Surgeons Score: MD 5.08; 95% CI 3.67 to 6.49; I² = 0.00%; 95% PI 1.98-8.18), and better postoperative ROM in terms of forward elevation and external rotation. However, the evidence regarding postoperative abduction was insufficient.

CONCLUSION

Meta-analytic pooling of current evidence showed a significant association between the application of FSAs and favourable clinical outcomes in terms of postoperative complications, radiographical findings, functional recovery, and postoperative elevation and external rotation.

Improved outcomes for proximal humerus fracture open reduction internal fixation augmented with a fibular allograft in elderly patients: a systematic review and meta-analysis

BACKGROUND

To date, no meta-analysis has been performed on the efficacy of fibular allograft augmentation for the management of proximal humerus fractures. The purpose of this study was to evaluate the radiographic and clinical outcomes of proximal humerus fractures treated with a locking compression plate (LCP) with or without fibular allograft augmentation.

METHODS

The Cochrane Database of Systematic Reviews, the Cochrane Register of Controlled Trials, PubMed, MEDLINE, Web of Science, and SCOPUS were queried in June of 2021 for literature comparing the radiographic and clinical outcomes for patients with proximal humerus fractures that were treated with an LCP only or an LCP augmented with a fibular allograft. Data describing study design, level of evidence, demographic information, final follow-up, radiographic changes in humeral head height (HHH), radiographic changes in neck shaft angle (NSA), final American Shoulder and Elbow Surgeons (ASES) scores, final Constant-Murley scores, and major complications were collected. Risk of bias was assessed using the Methodological Index for Non-Randomized Studies (MINORS). A meta-analysis was performed using pooled weighted mean differences (WMD) to compare changes in HHH, NSA, final ASES and final Constant-Murley scores between the 2 groups; a pooled odds ratio (OR) was used to compare complications between the groups.

RESULTS

Ten studies with a total of 802 patients were identified. There was a significant difference that favored patients augmented with a fibular allograft for change in HHH (WMD = -2.40; 95% confidence interval [CI], -2.49 to -2.31; P < .00001), change in NSA (WMD = -5.71; 95% CI, -6.69 to -4.72; P < .00001), final ASES scores (WMD = 5.08; 95% CI, 3.69-6.48; P < .00001), and OR for developing a major complication (OR = 0.37; 95% CI, 0.23-0.59; P < .0001). There was no significant difference in final Constant-Murley scores (WMD = 3.36; 95% CI, -0.21 to 6.93; P = .06) or revision surgery rate (P = .182) between the 2 groups.

CONCLUSION

The pooled WMD and prediction interval suggest that 95% of patients with proximal humerus fractures treated with an LCP augmented with a fibular allograft will have improved radiographic outcomes, improved ASES clinical outcome scores, and decreased odds of a major complication when compared with patients treated with an LCP alone. Limitations of this study include a relatively short average final follow-up time (<2 years) and a potential lack of standardization for radiographic outcomes among included studies.

The potential of locking plate with intramedullary fibular allograft to manage proximal humeral fracture with an unstable medial column

PURPOSE

To evaluate the potential of locking compression plate with intramedullary fibular allograft in managing proximal humeral fractures with an unstable medial column.

METHODS

Between March 2007 and March 2015, we retrospectively analyzed 63 patients who underwent locking plate fixation for proximal humeral fracture with an unstable medial column. All patients were assigned into group 1 (patients treated with locking plate) and group 2 (patients treated with locking plate with intramedullary fibular allograft). Groups 1 and 2 were composed of 29 and 34 patients, respectively. We analyzed bone union, the neck-shaft angle, the Constant score, the range of motion, and complications.

RESULTS

The mean average bone union time of the patients was 13.9 weeks in group 1 and 11.3 weeks in group 2. The average Constant score was 67.4 in group 1 and 73.6 in group 2 (p < 0.05). The mean preoperative NSA, postoperative NSA, and NSA at the last follow-up were 104.4°, 125.8°, and 115.8°, respectively, in group 1, and 109.0°, 130.3°, and 127.1°, respectively, in group 2. The mean forward flexion, abduction, external rotation, and internal rotation were 109.0°, 48.2°, 34.0°, and L5, respectively, in group 1, and 127.5°, 118.2°, 38.7°, and L1, respectively, in group 2. In group 1, avascular necrosis occurred in one patient and screw cutout in two patients. In group 2, screw cutout occurred in one patient.

CONCLUSION

In patients aged over 65 years with proximal humeral fractures, an unstable medial column was associated with poor clinical results owing to varus collapse. To prevent this, an intramedullary fibular allograft was used, and radiologic and clinical results were better with this approach than with a locking plate alone. Therefore, locking plate fixation using a fibular allograft is one of the possible treatments for patients with an unstable medial column.

Primary stability of cement augmentation in locking plate fixation for proximal humeral fractures: A comparison of absorbable versus non-absorbable cement

BACKGROUND

Cement augmentation has been suggested to increase the stability of screw anchoring in osteoporotic humeral fractures. Initial results are promising but may be jeopardized by cement leakage into the joint and difficult implant removal. Absorbable cement might have advantages in this regard, but it is unclear if the primary stability of both techniques is equivalent to each other. Therefore, this study aimed to compare its primary stability with that of non-absorbable cement augmentation.

METHODS

Nineteen cadaveric humeri with two-part fracture models were treated with locking plate osteosynthesis and cement augmentation using either absorbable calcium phosphate cement (group 1) or polymethylmethacrylate (group 2). Fracture movement, stiffness, failure mode, and ultimate load under cyclic compressive loading were examined and compared between the groups.

FINDINGS

The absolute and relative stiffness values in group 1 were significantly smaller than those in group 2 after 50 cycles (group 1: 114 ± 38 N/mm and 94 ± 8% vs. group 2: 188 ± 71 N/mm and 106 ± 9%; p₅₀ = 0.022), 2000 cycles (group 1: 97 ± 34 N/mm and 81 ± 15% vs. group 2: 153 ± 47 N/mm and 88 ± 15%; p₂₀₀₀ = 0.028), and 5000 cycles (group 1: 98 ± 40 N/mm and 81 ± 22% vs. group 2: 158 ± 40 N/mm and 92 ± 16%; p₅₀₀₀ = 0.028). The failure load was not statistically significantly different between the groups.

INTERPRETATION

Although the PMAA group showed higher values for absolute and relative stiffness, no statistically significant difference was found in the primary stability between absorbable and non-absorbable cement augmentation supporting plate osteosynthesis in proximal humeral fractures. In view of the potential advantages of bio-absorbable cement during the healing process, its use should be considered for the augmentation and stabilization of osteoporotic fractures.

The forgotten fragment: additional lesser tuberosity fixation of 4-part proximal humeral fractures-a biomechanical investigation

BACKGROUND

Fractures of the proximal humerus are common. The most frequent surgical treatment option is open reduction and locking plate fixation. Multifragmentary fractures, including 3- and 4-part fractures, are especially challenging to treat because they correlate with an increased risk of fixation failure. In the past, several mechanisms of additional fixation were investigated, but none directly addressed the lesser tuberosity (LT). The goal of this study was to investigate the biomechanical impact of additional anterior fracture fixation in lateral locked plating (LLP) of 4-part proximal humeral fractures (PHFs).

METHODS

Twenty-seven fresh frozen human shoulder specimens (mean age, 80 years) with intact rotator cuffs (RCs) were randomized into 4 groups: 3-part PHF with LLP and RC cerclage (n = 6); 4-part PHF with LLP and RC cerclage as standard of care (n = 7); 4-part PHF with LLP, RC cerclage, and 2 anterior 3.5-mm cortical screws (n = 7); and 4-part PHF with LLP, RC cerclage, and additional anterior one-third tubular plate (additional anterior plating [AAP], n = 7). Static load of the RC was simulated with weights. A force-controlled cyclic loading test was performed with a servo-hydraulic testing machine, followed by load-to-failure testing. An optical motion capture system recorded humeral head range of motion.

RESULTS

LLP of a 4-part PHF showed more humeral head motion than LLP of a 3-part PHF without fracture of the LT (P < .001). Fixing the LT to the humeral head with two 3.5-mm screws significantly reduced humeral head motion compared with LLP with RC cerclage alone (P < .006). Using AAP significantly increased the construct stiffness compared with the standard of care (P = .03).

CONCLUSION

LLP of a 4-part PHF is biomechanically less stable than LLP of a 3-part PHF without fracture of the LT. Additional screw fixation of the LT in 4-part PHFs improves stability compared with LLP alone. In case of metaphyseal comminution, AAP is favorable from a biomechanical perspective.

Reduction and fixation of proximal humeral fracture with severe medial instability using a small locking plate

BACKGROUND

Currently, the reduction and support of comminuted medial cortex of humeral fracture remains a challenge, Therefore, a novel reduction and fixation technique that employs an anteromedial small locking plate was explored in this study, and its viability and the associated complications were assessed.

METHODS

Fifteen cases of proximal humeral fractures with medial instability (five cases were classified as three-part and ten as four-part by Neer classification) were treated by the proposed reduction technique using an anteromedial small locking plate. Subsequently, the radiological and clinical outcomes were evaluated over an average follow-up period of 18.53 months.

RESULTS

The average operation time was 108 min (range, 70-130 min), and the mean fracture union time in all patients was 12.13 weeks (range, 8-16 weeks). Complications such as infection and neurovascular injury were not observed. Postoperative X-ray showed avascular necrosis and screw penetration in one patient, while screw penetration, varus malunion, or significant reduction loss was not found in the other cases. The mean Constant score was 79.8 (range, 68-92) during the final visit.

CONCLUSIONS

The use of an anteromedial small locking plate improved the reduction efficiency, reconstructed the medial support, and alleviated the occurrence of complications in proximal humeral fractures with medial instability.

Screw-Tip Augmented Locked Plating Versus Primary Reverse Total Shoulder Arthroplasty in Displaced Proximal Humeral Fractures: A Retrospective Comparative Cohort Study With a Mean Follow-Up of 39 Months

Introduction

This study compared the clinical and radiologic outcomes of screw-tip augmented locking plate osteosynthesis (STA) vs primary reverse total shoulder arthroplasty (RSA) in elderly patients with displaced proximal humeral fractures.

Methods

60 patients (age >65 years) with a displaced proximal humeral fracture underwent open reduction and internal fixation with locking plate and fluoroscopy controlled screw-tip augmentation. Sixty matched individuals (age, gender, fracture pattern, and mean follow-up) treated by RSA for fractures were identified from the institutional database and outcomes as well as occurring complications and need for revision surgery were compared.

Results

At 39 months’ follow-up, 25 patients in the STA group (mean age 74.5 ± 12 years, 76.7% woman) showed a mean Constant Score (CS) of 68 ± 18.8 points. Mean %CS compared to the contralateral side was 81.6 ± 19.8%. Of 60 matched individuals in the RSA group, 22 patients (mean age 78.9 ± 8.2 years, 76.7% woman) showed a mean CS of 60.6 ± 21.2 points (P = .33), and the mean %CS compared to the contralateral side was 81.6 (74.7 ± 18.6)% (P = .14). The overall complication rate in STA group was 32% (secondary varus or valgus displacement >10°, n = 4, avascular necrosis, n = 4). In RSA group, the overall complication rate was 4.5% (P = <.05). We observed one early onset infection. Revision surgery with removal of the prosthesis and PMMA spacer implantation for two-stage revision was necessary. The follow-up rate was 41.7 vs 36.7%.

Conclusions

Screw-tip augmented locked plating and reverse total shoulder arthroplasty result in comparable satisfying functional outcome 3 years following a displaced proximal humeral fracture in elderly patients. However, we noted a higher complication and revision rate in the STA group. In contrast, primary reversed shoulder arthroplasty resulted in a lower rate of complications and revisions, which may be beneficial in elderly patients.

DOES CEMENT CURING CAUSE CONCERNING INCREASE OF THE TEMPERATURE WHEN DELIVERED IN THE HUMAN HUMERUS?

For the treatment of humeral fractures, numerous strategies exist to improve the clinical outcome of the reconstruction and to reduce the incidence of fixation failure. Injection of acrylic-based cements to reinforce the bone and/or augment the screws is one option. The heat generated during cement polymerization raises some concerns, as it could cause tissue damage. The first aim of this study was to measure the temperature over time during polymerization when acrylic cements are delivered inside the bone to treat fracture. The second aim was to assess if the ISO-5833:2002 standard can predict what happens in a real bone. Different tests were performed using two acrylic-based cements (Mendec and Cal-Cemex): (i) the ISO-5833:2002 standard (Annex C); (ii) tests on human bones (humeral diaphysis and humeral head) injected with cement to simulate fracture treatment. In the humeri, the highest temperature was measured in the diaphysis (68.6∘C for Mendec, 62.7∘C for Cal-Cemex). These values are comparable with the temperature reached in other consolidated applications (vertebroplasty). Exposure to high temperature was shorter for the diaphysis than for the head. For both cements, in both the diaphysis and the head, temperatures exceeded 48∘C for less than 10[Formula: see text]min. This is within the threshold for tissue necrosis. The ISO-5833:2002 yielded significantly different results in terms of maximum temperature (difference exceeding 15∘C) and exposure to temperature above 48∘C and 45∘C. This discrepancy is probably due to a combination of factors affecting the amount of heat produced and dissipated (e.g., amount and shape of the cement, thermal conductivity).

The choice between allograft or demineralized bone matrix is not unambiguous in trauma surgery

In fracture surgery, large bone defects and non-unions often require bone transplantation, and alternatives to autograft bone substitutes in the form of allografts from bone banks and the derivate demineralised bone matrix (DBM) are widely used. With a focus on efficacy, clinical evidence, safety, cost, and patient acceptance, this review evaluated the difference between allogeneic allograft or DBM as a bone substitute in trauma surgery. The efficacy in supporting bone healing from allograft and DBM is highly influenced by donor characteristics and graft processing. Mechanical stability is achieved from a structural graft. Based on the existing literature it is difficult to identify where DBM is useful in trauma surgery, and the level of evidence for the relevant use of allograft bone in trauma is low. The risk of transmitting diseases is negligible, and the lowest risk is from DBM due to the extensive processing procedures. A cost comparison showed that DBM is significantly more expensive. The experiences of dental patients have shown that many patients do not want to receive allografts as a bone substitute. It is not possible to definitively conclude whether it makes a difference if allograft or DBM is used in trauma surgery. It is ultimately the surgeon's individual choice, but this article may be useful in providing considerations before a decision is made.

Principles of Locking Plate Fixation of Proximal Humerus Fractures

Proximal humerus fractures are common, particularly in elderly patients and those with osteopenia or osteoporosis. Although nonsurgical management results in satisfactory outcomes for most patients, surgical treatment is indicated in select cases. Despite an increasing trend toward arthroplasty, open reduction and internal fixation of proximal humerus fractures can still provide excellent clinical outcomes. Proper technique for internal fixation of the proximal humerus requires an understanding of osseous and neurovascular anatomy. In particular, understanding reliable regions of biomechanically superior bone can help prevent failure of fixation. Biomechanical studies have shown that locked plating of proximal humerus fractures provides stable fixation. Cadaveric and finite element models underscore the importance of screw placement in the posteromedial metaphysis. When medial column support is challenging to obtain, or when bone quality is poor, augmentation with bone autograft, allograft, and/or synthetic composites can improve the biomechanics of internal fixation constructs. The purpose of this review is to outline the anatomic, biologic, and biomechanical principles of plate fixation for proximal humerus fractures to provide evidence-based recommendations for optimizing fixation and preventing fixation failure.

Supporting the medial hinge in proximal humerus fractures with an intramedullary plate

Proximal humerus fractures are common and approximately 20% of displaced fractures may benefit from surgery. A lack of medial support is found to be a predictor of failure after surgical fixation of proximal humerus fractures. The optimal technique for restoring the medial hinge is unclear. We describe two cases of patients with a dislocated 4-part humerus fracture treated with a locking plate and an additional small intramedullary plate to support the medial hinge. This technique is simple and allows for an enhanced stability of the medial hinge during and after surgery.

[Research progress on medial support augmentation of plate osteosynthesis for proximal humeral fractures]

Objective

To review the literature about the clinical application and research progress on medial support augmentation of plate osteosynthesis for proximal humeral fractures, and to provide reference for clinical treatment.

Methods

The literature concerning medial support augmentation of plate osteosynthesis for proximal humeral fractures in recent years was extensively reviewed, as well as the biomechanical benefit and clinical advantage were analyzed thoroughly.

Results

Medial support augmentation of plate osteosynthesis for proximal humeral fractures is very important, especially in osteoporotic and/or comminuted fractures. Many medial support augmentation methods have been proposed which can be divided into extramedullary support and intramedullary support. It can also be divided into autogenous bone support and allogenic bone support according to the material and source, divided into medial column support, calcar support, and humeral head support according to the support site, and divided into fibular shaft support, femoral head support, anatomic fibula support according to the shape of the augmented fixation. At present, clinical and biomechanical researches show that medial support augmentation is an effective treatment for proximal humeral fractures.

Conclusion

As an important treatment strategy for the treatment of proximal humeral fractures, the medial support augmentation of plate osteosynthesis gets the focus from the biomechanical studies and clinical treatment. However, there are still widespread controversies among orthopedic surgeons regarding the support mode, site, implant shape, and material of medial column support for augmentation of proximal humeral fractures. More high-quality clinical trials and biomechanical researches as well as multi-disciplinary integration, are needed to provide better strategy treatment for the treatment of proximal humeral fractures.

Dynamic locking screws in proximal humeral plate osteosynthesis demonstrate superior fixation properties: a biomechanical study

Purpose

Angular stable implants reduced the complication rate in the treatment of humeral head fractures. But the failure rate is still high. To further reduce the risk of cut-out, cement augmentation of screws was introduced. A reason for failure of plate osteosynthesis might be the extremely high stiffness of the screw-plate interface leading to a loss of reduction and cut-out of screws. A more homogeneous distribution of the forces on all screws may avoid secondary dislocation. We hypothesize that dynamic osteosynthesis minimizes screw loosening and results in a higher load to failure than standard locking screws.

Methods

Twelve paired human humerus specimens were analysed. A standardized three-part fracture model with a metaphyseal defect was simulated. Within each pair of humeri, one was fixed with a Philos plate and standard locking screws (LS), whereas the other humerus was fixed with a Philos plate and dynamic locking screws (DLS). A cyclic varus-bending test or a rotation test with increasing loading force was performed until failure of the screw-bone-fixation.

Results

In the varus bending test, pairs failed by screw loosening in the humeral head. The LS-group reached 2901 (601–5201) load cycles until failure, while the DLS-group failed after 3731 (2001–5601) cycles. This corresponds to a median loading of 195 N for the LS-group and 235 N for the DLS-group (p = 0.028). In the rotation test the LS-group reached a median of 1101 (501–1501) load cycles until failure of fixation occurred, while the DLS-group failed after 1401 (401–2201) cycles (p = 0.225).

Conclusions

Plate fixation using dynamic locking screws for the treatment of proximal humerus fractures demonstrated more load cycles until failure compared to standard locking plate osteosynthesis.

Cement augmentation of calcar screws may provide the greatest reduction in predicted screw cut-out risk for proximal humerus plating based on validated parametric computational modelling: Augmenting proximal humerus fracture plating

Aims

Fixation of osteoporotic proximal humerus fractures remains challenging even with state-of-the-art locking plates. Despite the demonstrated biomechanical benefit of screw tip augmentation with bone cement, the clinical findings have remained unclear, potentially as the optimal augmentation combinations are unknown. The aim of this study was to systematically evaluate the biomechanical benefits of the augmentation options in a humeral locking plate using finite element analysis (FEA).

Methods

A total of 64 cement augmentation configurations were analyzed using six screws of a locking plate to virtually fix unstable three-part fractures in 24 low-density proximal humerus models under three physiological loading cases (4,608 simulations). The biomechanical benefit of augmentation was evaluated through an established FEA methodology using the average peri-screw bone strain as a validated predictor of cyclic cut-out failure.

Results

The biomechanical benefit was already significant with a single cemented screw and increased with the number of augmented screws, but the configuration was highly influential. The best two-screw (mean 23%, SD 3% reduction) and the worst four-screw (mean 22%, SD 5%) combinations performed similarly. The largest benefits were achieved with augmenting screws purchasing into the calcar and having posteriorly located tips. Local bone mineral density was not directly related to the improvement.

Conclusion

The number and configuration of cemented screws strongly determined how augmentation can alleviate the predicted risk of cut-out failure. Screws purchasing in the calcar and posterior humeral head regions may be prioritized. Although requiring clinical corroborations, these findings may explain the controversial results of previous clinical studies not controlling the choices of screw augmentation.

Does the magnitude of injuries affect the outcome of proximal humerus fractures treated by locked plating (PHILOS)?

PURPOSE

Health-related quality of life (HRQoL) becomes increasingly relevant in an aging society. Functional outcome (FO) and the patient-reported outcome (PRO) after surgical treatment of proximal humerus fractures (PHF) depends on numerous factors, including patient- and injury-specific factors. There is little evidence on how the FO and the PRO vary in different settings such as monotrauma or multiple injuries, even though the PHF is one of the more frequent fractures. In addition, to a previous study, on multiple injured patients and upper extremity injuries, the aim of the current study was to investigate the impact of multiple injuries, quantified by the ISS, on the FO and PRO after surgically treated PHF by PHILOS.

METHODS

A retrospective cohort-study was conducted with an additional follow-up by a questionnaire. HRQoL tools such as range of motion (ROM), the Quick-Disability of Arm Shoulder and Hand score (DASH), EuroQol Five Dimension Three Levels (EQ-5D-3L), and EuroQol VAS (EQ-VAS) were used. The study-population was stratified according to ISS obtained based on information at discharge into Group I/M-H (ISS < 16 points) and Group PT-H (ISS ≥ 16). Median outcome scores were calculated and presented.

INCLUSION CRITERIA

adult patients (> 18 years) with PHF treated at one academic Level 1 trauma center between 2007 and 2017 with Proximal Humeral Inter-Locking System (PHILOS) and preoperative CT-scan. Group stratification according Injury Severity Score (ISS): Group PT-H (ISS ≥ 16 points) and Group I/M-H (ISS < 16 points).

EXCLUSION CRITERIA

oncology patients, genetic disorders affecting the musculoskeletal system, paralysis or inability to move upper extremity prior or after injury, additional ipsilateral upper limb fractures, open injuries, associated vascular injuries as well brachial plexus injuries and nerve damages. Follow-up 5-10 years including PRO: EQ-5D-3L and EQ-VAS. FO, including DASH and ROM. The ROM was measured 1 year after PHILOS.

RESULTS

Inclusion of 75 patients, mean age at injury was 49.9 (± 17.6) years. The average follow-up period in Group I/M-H was 6.18 years (± 3.5), and in Group PT-H 5.58 years (± 3.1). The ISS in the Group I/M-H was 6.89 (± 2.5) points, compared to 21.7 (± 5.3) points in Group PT-H (p ≤ 0.001). The DASH-score in Group I/M-H was 9.86 (± 13.12 and in Group PT-H 12.43 (± 15.51, n.s.). The EQ-VAS in Group I/M-H was 78.13 (± 19.77) points compared with 74.13 (± 19.43, n.s.) in Group PT-H. DASH, EQ-VAS as well as ROM were comparable in Groups I/M-H and PT-H (9.9 ± 13.1 versus 12.4 ± 15.5, n.s.). The EQ-5D-3L in Group I/M-H was 0.86 (± 0.23) points compared to Group PT-H 0.72 (± 0.26, p ≤ 0.017). No significant differences could be found in Group I/M-H and PT-H in the severity of traumatic brain injury (TBI). A multivariable regression analyses was performed for DASH, EQ-5D-3L and EQ-VAS. All three outcome metrics were correlated. There was a significant difference between the EQ-5D-3L and the ISS (Beta-Coefficient was 0.86, 95% low was 0.75, 95% high was 0.99, p ≤ 0.041). No significant correlation could be found comparing DASH, EQ-5D-3L and EQ-VAS to age, gender and TBIs.

CONCLUSION

Multiple injuries did not affect the DASH, ROM or EQ-VAS after PHILOS; but a higher ISS negatively affected the EQ-5D-EL. While the ROM and DASH aim to be objective measurements of functionality, EQ-5D-3L and EQ-VAS represent the patients' PRO. The FO and PRO outcomes are not substitutable, and both should be taken into consideration during follow-up visits of multiple injured patients. Future research should prospectively explore whether the findings of this study can be recreated using a larger study population and investigate if different FO and PRO parameters come to similar conclusions. The gained information could be used for an enhanced long-term evaluation of patients who suffered a PHF from multiple injuries to meet their multifarious conditions.

LEVEL OF EVIDENCE

II.

Cross-elements to enhance fixation in osteoporotic bone with application to proximal humeral locking plates: a biomechanical study

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.

Synthetic Bone Substitutes and Mechanical Devices for the Augmentation of Osteoporotic Proximal Humeral Fractures: A Systematic Review of Clinical Studies

BACKGROUND

Different augmentation techniques have been described in the literature in addition to the surgical treatment of proximal humeral fractures. The aim of this systematic review was to analyze the use of cements, bone substitutes, and other devices for the augmentation of proximal humeral fractures.

METHODS

A systematic review was conducted by using PubMed/MEDLINE, ISI Web of Knowledge, Cochrane Library, Scopus/EMBASE, and Google Scholar databases according the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines over the years 1966 to 2019. The search term "humeral fracture proximal" was combined with "augmentation"; "polymethylmethacrylate, PMMA"; "cement"; "bone substitutes"; "hydroxyapatite"; "calcium phosphates"; "calcium sulfate"; "cell therapies", and "tissue engineering" to find the literature relevant to the topic under review.

RESULTS

A total of 10 clinical studies considered eligible for the review, with a total of 308 patients, were included. Mean age at the time of injury was 68.8 years (range of 58-92). The most commonly described techniques were reinforcing the screw-bone interface with bone PMMA cement (three studies), filling the metaphyseal void with synthetic bone substitutes (five studies), and enhancing structural support with metallic devices (two studies).

CONCLUSION

PMMA cementation could improve screw-tip fixation. Calcium phosphate and calcium sulfate injectable composites provided good biocompatibility, osteoconductivity, and lower mechanical failure rate when compared to non-augmented fractures. Mechanical devices currently have a limited role. However, the available evidence is provided mainly by level III to IV studies, and none of the proposed techniques have been sufficiently studied.