A comprehensive update on current fixation options for two-part proximal humerus fractures: a biomechanical investigation

Biomechanical design optimization of proximal humerus locked plates: A review

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.

Biomechanical testing of osteosynthetic locking plates for proximal humeral shaft fractures - a systematic literature review

Proximal humeral shaft fractures can be treated with helically deformed bone plates to reduce the risk of iatrogenic nerve lesion. Controversially to this common surgical technique that was first established in 1999, no biomechanical investigation on humeral helical plating is recorded by other reviews, which focus on proximal fractures exclusively. Does an additional scope for shaft fractures reveal findings of helical testing? The present systematic literature review was performed based on guidelines by Kitchenham et al. to systematically search and synthesize literature regarding biomechanical testing of osteosynthetic systems for proximal humeral shaft fractures. Therefore, a systematic approach to search and screen literature was defined beforehand and applied on the findings of the database PubMed®. Synthesized information of the included literature was categorized, summarized and analyzed via descriptive statistics. Out of 192 findings, 22 publications were included for qualitative synthesis. A wide range of different test methods was identified, leading to a suboptimal comparability of specific results between studies. Overall, 54 biomechanical test scenarios were identified and compared. Physiological based boundary conditions (PB-BC) were referenced in 7 publications only. One study of testing straight and helical dynamic compression plates without PB-BCs was identified, showing significant differences under compressional loading. The absence of test standards of specific fields like humeral fractures lead to a high variance in biomechanical testing of osteosynthetic locking plates for proximal humeral shaft fractures. Physiological approaches offer realistic test scenarios but need to be uniformed for enhanced comparability between studies. The impact of helically deformed locking plates under PB-BC was not identified in literature.

Straight antegrade humeral nailing and risk of iatrogenic injury of supraspinatus tendon footprint: An MRI study

Background

Straight antegrade humeral nailing (SAHN) is associated with excellent clinical results in proximal humerus fractures. The optimal entry point is the top of the humeral head. However, the anatomy is variable, and the entry point can affect supraspinatus tendon footprint (SSP-F) or fracture reduction. The aim of this study was to analyze the relationship between the SSP-F and SAHN entry point by analyzing magnetic resonance imaging (MRI) studies of the humerus.

Methods

In total 58 MRI studies of entire humerus were reviewed. The mean age was 51.6 ± 12.4 years, with 40 female patients. The distance between the SSP-F and the SAHN insertion point (critical distance: CD), the width of the footprint, and the neck-shaft angle (NSA) were measured. Univariate and multivariate analysis were performed.

Results

The mean CD was 7.51 mm ± 2.81 (0-12.9 mm) with 51.7% of proximal humerus "critical type" (CD <8 mm). The CD was found to be lower in females, with no difference found with varying age (62.5% "critical type"). CD correlated with NSA (linear regression). "Critical type" correlated with female gender and NSA (logistic regression).

Discussion

More than half of the humerus are "critical types" as to SAHN and may, therefore, be at risk for procedure-related complications.

What is the interobserver agreement of displaced humeral surgical neck fracture patterns?

Background: The Boileau classification distinguishes three surgical neck fracture patterns: types A, B, and C. However, the reproducibility of this classification on plain radiographs is unclear. Therefore, we questioned what the interobserver agreement and accuracy of displaced surgical neck fracture patterns is categorized according to the modified Boileau classification. Does the reliability to recognize these fracture patterns differ between orthopedic residents and attending surgeons?Methods: This interobserver study consisted of a randomly retrieved series of 30 plain radiographs representing clinical practice in a level 1 and a level 2 trauma center. Radiographs were included from patients (≥18 years) who sustained an isolated displaced surgical neck fracture if they were taken ≤1 week after initial injury. A ground truth was established by consensus among three senior orthopedic surgeons. All images were assessed by 17 orthopedic residents and 17 attending orthopedic trauma surgeons.Results: Agreement for the modified Boileau classification was fair (κ=0.37; 95% confidence interval [CI], 0.36–0.38) with an accuracy of 62% (95% CI, 57%–66%). Comparison of interobserver variability between residents and attending surgeons revealed a significant but clinically irrelevant difference in favor of attending surgeons (0.34 vs. 0.39, respectively, Δ κ=0.05, 95% CI, 0.02–0.07).Conclusions: The modified Boileau classification yields a low interobserver agreement with an unsatisfactory accuracy in a panel of orthopedic residents and attending surgeons. This supports the hypothesis that surgical neck fractures are challenging to categorize and that this classification should not be used to determine prognosis if only plain radiographs are available.

Biomechanical comparison of tuberosity-based proximal humeral locking plate compared to standard proximal humeral locking plate in varus cantilever bending

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.

[Comparison of locking plate and intramedullary nail in treatment of Neer two- and three-part fractures of the proximal humerus in the elderly]

OBJECTIVE

To compare the effectiveness of locking plate and intramedullary nail in treatment of Neer two- and three-part fractures of the proximal humerus in the elderly.

METHODS

A retrospective analysis was conducted on 86 elderly patients with Neer two- and three-part fractures of the proximal humerus met the selection criteria between January 2015 and December 2018. Forty-six patients were treated with locking plate fixation (locking plate group), and 40 patients with intramedullary nail fixation (intramedullary nail group). There was no significant difference in gender, age, cause of injury, fracture side and type, time from injury to operation, and comorbidities between the two groups ( P>0.05). Visual analogue scale (VAS) score, American Shoulder and Elbow Surgery (ASES) score, Constant-Murley score, and shoulder range of motion (forward flexion, abduction, and external rotation) were compared between the two groups. X-ray films were taken to assess the fracture healing, and the neck-shaft angle was measured at 2 days after operation and at last follow-up, and the difference between the two time points was calculated.

RESULTS

Patients in both groups were followed up 18-40 months, with an average of 30.4 months. There was no significant difference in follow-up time between the two groups ( t=-0.986, P=0.327). X-ray films reexamination showed that the fractures of two groups healed, and the healing time was (11.3±2.1) weeks in locking plate group and (10.3±2.0) weeks in intramedullary nail group, which had significant difference between the two groups ( t=2.250, P=0.027). The difference of neck-shaft angle was (7.63±7.01)° in locking plate group and (2.85±2.82)° in intramedullary nail group, which had significant difference between the two groups ( t=4.032, P<0.001). There was no significant difference in Constant-Murley score, ASES score, VAS score, and shoulder range of motion between the two groups at last follow-up ( P>0.05). Complications occurred in 13 cases (28.3%) of locking plate group and in 4 cases (10.0%) of intramedullary nail group, and the difference between the two groups was significant ( χ ²=4.498, P=0.034).

CONCLUSION

Both locking plates and intramedullary nails can be used for the treatment of Neer two- and three-part fractures of the proximal humerus in the elderly. The intramedullary nail fixation surgery is more minimally invasive, which has fewer postoperative complications and faster fracture healing.

Third-generation intramedullary nailing for displaced proximal humeral fractures in the elderly: quality of life, clinical results, and complications

INTRODUCTION

Antegrade insertion of third-generation intramedullary nail (IMN) has been shown to provide excellent results in young patients for treatment of displaced two-part surgical neck fracture. In elderly patients, osteoporosis makes internal fixation problematic and frequently contributes to failed fixation and poor clinical results. The purpose of this study was to report the health-related quality of life (HRQoL), functional results, and postoperative complications obtained with straight third-generation antegrade nailing of proximal humerus fractures (PHFs) in elderly patients.

METHODS

A retrospective review of 32 patients aged 80 y.o. or older presenting a two-part or three-part PHFs treated with a straight IMN with a minimum follow-up of 12 months. Results assessed included 1) radiographic measures 2) clinical data: Charlson Comorbidity Index (CCI), VAS, range of motion (ROM), Individual Relative Constant score (IRC), Simple Shoulder Test (SST) and 3) Health-related Quality of life (HRQoL) with the EQ-5D index/EQ-VAS.

RESULTS

Mean age was 82.1 (range 80-90) and mean follow-up was 45.6 months (range 16-53 months) with 91% of female patients and a mean CCI 4.6. 81% were two-part surgical neck fractures and 19% were three-part greater tuberosity fractures. The mean neck-shaft angle (NSA) at final follow-up was 132º ± 17.9º. 15.6% underwent hardware removal because of subacromial impingement and one patient (3%) was revised to RSA because of severe secondary fracture displacement. Mean IRC was 67,7 ± 30, the mean SST and VAS-Pain were 8.1 ± 3.1 and 3.2 ± 3.2, respectively, and the mean EQ-5D/EQ-VAS were 0.40 ± 0.33/64.2 ± 8.9. At last review, mean active forward flexion, abduction, and external rotation were 115º ± 35º, 100º ± 35º, and 20º ± 15º, respectively.

CONCLUSION

Appropriate selection of fracture and proper operative technique with a third-generation nail result in good functional results and good HRQol with a low complication rate in elderly population.

Muscular Forces Responsible for Proximal Humeral Deformity After Fracture

OBJECTIVES

To evaluate the contribution of each of the rotator cuff muscles and deltoid to fracture deformity in a 2-part proximal humerus fracture model. Our hypothesis was that superior cuff muscles would have the greatest contribution to coronal plane deformity, whereas muscles with anterior and posterior attachments would have the greatest contribution to axial and sagittal plane deformity.

METHODS

A medial wedge osteotomy was created in 8 cadaveric shoulder specimens. A custom shoulder testing system was used to load each rotator cuff muscle and deltoid under increasing loading conditions. Fracture displacement was measured using a Microscribe digitizing system. The primary outcome was the contribution of each muscle to varus collapse. Secondary outcomes included contributions of each muscle to apex anterior/posterior deformity and humeral head anteversion/retroversion.

RESULTS

Unbalanced loading of the supraspinatus resulted in the greatest varus deformity (34.5 ± 2.3 degrees), followed by the infraspinatus (22.3 ± 3.6 degrees) and subscapularis (21.7 ± 3.1 degree) (P < 0.05). Unbalanced loading of the subscapularis induced the greatest apex posterior (27.5 ± 4.8 degrees, P < 0.05) and retroversion (39.0 ± 5.6 degrees, P < 0.05) deformity, whereas the infraspinatus induced the greatest apex anterior (8.7 ± 3.4 degrees, P > 0.05) and anteversion (17.7 ± 5.7 degrees, P > 0.05) deformity.

CONCLUSIONS

In this proximal humerus fracture model, the supraspinatus was the primary driver of varus deformity, whereas the subscapularis and infraspinatus contributed to apex posterior/retroversion and apex anterior/anteversion, respectively. The subscapularis and infraspinatus are also important secondary drivers of varus deformity. This study establishes a physiologically relevant fracture model that mimics in vivo conditions for future biomechanical testing.

Differences in soft tissue damage using a percutaneous versus open approach for antegrade straight humeral nailing: a quantitative and qualitative anatomical study

BACKGROUND

Percutaneous insertion of third-generation straight humeral nails is a recent alternative to the conventional open method. Rather than splitting, retracting and subsequently repairing the supraspinatus fibers to visualize the humeral head entry site, the percutaneous approach utilizes a cannulated awl to enter the intramedullary canal through the supraspinatus fibers without visualizing internal shoulder structures. Despite recent evidence demonstrating satisfactory outcomes in the percutaneous method, the potential for iatrogenic injury to the rotator cuff and other shoulder structures is not fully understood.

MATERIALS AND METHODS

We performed an anatomical study of 46 shoulders in 23 cadavers to compare damage caused to internal shoulder structures between the open and percutaneous techniques. Dimensions and morphologies of supraspinatus and humeral head perforations were recorded.

RESULTS

The percutaneous technique produced greater latitudinal tearing (p = 0.002) and less longitudinal tearing (p < 0.001) of muscle fibers, however there was no difference in supraspinatus hole area (p = 0.748). The long head biceps tendon was within 3 mm of the bone entry hole in 13 (28%) shoulders, with one shoulder in the open group exhibiting full tendon transection.

CONCLUSIONS

Percutaneous insertion of intramedullary nails using a cannulated awl appears to produce similar soft tissue and bone entry site morphology as compared to the conventional open technique. The percutaneous method was associated with slightly greater latitudinal tearing, however the effects of this remain to be clarified through clinical studies. External rotation should be avoided during instrumentation to reduce the risk of biceps tendon transection.

Implant Selection for Proximal Humerus Fractures

Proximal humerus fractures (PHF) are a common orthopedic injury; however, their treatment remains largely controversial with evidence supporting a wide array of treatments. Although many injuries can be treated nonoperatively, there has been much debate about surgical management of PHF. A detailed review of the literature was performed relative to operative management options specifically related to implant choices. Although no definitive answers are available regarding best practice, there is literature to guide operative decision-making and implant selection based on both patient- and surgeon-specific factors.

Nail Versus Plate: A Biomechanical Comparison of a Locking Plate Versus an Intramedullary Nail With an Angular Stable Locking System in a Shoulder Simulator With Active Muscle Forces Using a Two-Part Fracture Model

OBJECTIVES

To compare a locking compression plate versus an intramedullary nail with an angular stable locking system (ASLS) using a 2-part fracture model in a shoulder test bench.

METHODS

Twelve fresh frozen humeri were used for biomechanical testing in a shoulder simulator. A 2-part fracture model, with and without medial cortical support, was used to compare the locking plate and a nail with an ASLS. The varus impaction, varus per cycle motion, tilt, and tilt per cycle were analyzed.

RESULTS

No significant differences for the resulting forces in the glenoid fossa were evaluated. The stable fracture model showed no significant differences for the 2 groups. The median varus impaction was -0.96 degrees (range -0.55 to -4.26 degrees) in the plate group and 0.5 degrees (range -3.06 to 0.98 degrees) in the nail group, after 500 cycles of cyclic loading in the unstable fracture model. The plate group showed a significantly higher median varus impaction per cycle motion and median varus impaction at the 200th, 300th, and 400th cycle of physiological loading.

CONCLUSIONS

The intramedullary nail with the ASLS could be an alternative for patients suffering from osteoporosis and comorbidities.

ESTES recommendations on proximal humerus fractures in the elderly

PURPOSE

The section for the skeletal trauma and sport's injuries of the European Society for Trauma and Emergency Surgery (ESTES) appointed a task force group to reach a consensus among European countries on proximal humeral fractures.

MATERIAL/METHODS

The task force group organized several consensus meetings until a paper with final recommendations was confirmed during the ESTES Executive Board meeting in Berlin on 25 October 2018.

CONCLUSION

The Recommendations compare conservative and four possible operative treatment options (ORIF, nailing, hemi- and total reverse arthroplasty) and enable the smallest common denominator for the surgical treatment among ESTES members.

Intramedullary Fixation for Proximal Humeral Fractures

Proximal humeral fractures are a commonly encountered injury; however, no consensus has been reached for the ideal treatment. Current surgical fixation options include plate, plate with fibular strut allograft, intramedullary fixation, pinning, suture constructs, and external fixation. Each of these options possesses distinct advantages and disadvantages. With the evolution of implant design, a greater understanding of the mechanisms of failure of fixation, and the ability to preserve fracture biology, the management of proximal humeral fractures with intramedullary fixation has become an accepted treatment option. From a biomechanical perspective, intramedullary fixation may have advantages over laterally based fixation, in particular with fractures associated with significant calcar comminution. The ability to insert the implant from a superior starting point may help preserve vascular supply to the humeral head and tuberosities. With reported outcomes comparable with the aforementioned techniques and an evolving understanding of fracture characteristics and failures of fixation, intramedullary fixation represents an alternative treatment option for proximal humeral fractures with specific fixation and biologic advantages.

Displaced humeral surgical neck fractures: classification and results of third-generation percutaneous intramedullary nailing

BACKGROUND

The high rates of complications and reoperations observed with the early designs of first-generation (unlocked) and second-generation (bent design) humeral intramedullary nail (IMNs) have discouraged their use by most surgeons. The purpose of this study was to report the results of a third-generation (straight, locking, low-profile, tuberosity-based fixation) IMN, inserted through a percutaneous approach, for the treatment of displaced 2-part surgical neck fractures.

METHODS

We performed a retrospective review of 41 patients who underwent placement of a third-generation IMN to treat a displaced 2-part surgical neck fracture (AO/OTA type 11A3). The mean age at surgery was 57 years (range, 17-84 years). After percutaneous insertion through the humeral head, the IMN was used as a reduction tool. Static locking fixation was achieved after axial fracture compression ("back-slap" hammering technique). Patients were reviewed and underwent radiography with a minimum of 1 year of follow-up; the mean follow-up period was 26 months (range, 12-53 months).

RESULTS

Preoperatively, 3 types of surgical neck fractures were observed: with valgus head deformity (Type A = 8 cases), shaft translation without head deformity (Type B = 19 cases), or with varus head deformity (Type C = 14 cases). At final follow-up, all fractures went on to union, and the mean humeral neck-shaft angle was 132° ± 5°. We observed 2 malunions and 1 case of partial humeral head avascular necrosis. No cases underwent screw migration or intra-articular penetration. At last review, mean active forward elevation was 146° (range, 90°-180°) and mean external rotation was 50° (range, 20°-80°). The mean Constant-Murley score and Subjective Shoulder Value were 71 (range, 43-95) and 80% (range, 50%-100%), respectively.

CONCLUSIONS

Antegrade insertion of a third-generation IMN through a percutaneous approach provides a high rate of fracture healing, excellent clinical outcome scores, and a low rate of complications. No morbidity related to the passage of the nail through the supraspinatus muscle and the cartilage was observed. The proposed A, B, and C classification allows choosing the optimal entry point for intramedullary nailing.

Biomechanical analysis of plate systems for proximal humerus fractures: a systematic literature review

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.

Ultrasound evaluation of the rotator cuff after osteosynthesis of proximal humeral fractures with locking intramedullary nail

Objective

To evaluate supraspinatus tendon integrity with ultrasound (US) in patients submitted to proximal humeral fracture (PHF) fixation with a locking intramedullary nail.

Methods

Thirty-one patients with PHF treated with curvilinear locking intramedullary nail, aged between 50 and 85 years, were assessed by US at six months postoperatively and clinically at six and 12 months postoperatively. The primary aim was supraspinatus tendon integrity, evaluated by US at six months postoperatively. Secondary aims included the Constant-Murley, DASH score, and visual analog pain scores, as well as complications and reoperation rates.

Results

Full-thickness rotator cuff ruptures were observed in four patients (13%), supraspinatus ruptures in three cases (10%), and subscapularis ruptures in one case (3%). Partial ruptures were diagnosed in 10 cases (32%). The results using the Constant-Murley score at 12 months were 71.3 ± 15.2 points for the entire series, with 73.2 ± 16.1 points for patients without rotator cuff ruptures and 68.7 ± 14.1 points for those with partial or complete ruptures, without a statistically significant difference (p = 0.336). Complications, exclusively for rotator cuff ruptures, were observed in nine patients (29%).

Conclusion

A high rate of rotator cuff ruptures was demonstrated, with partial ruptures in 32% of cases and full-thickness ruptures in 13%. However, clinical results are satisfactory, and are not influenced by the presence of rotator cuff ruptures.

Locking intramedullary nails versus locking plates for the treatment of proximal humerus fractures

INTRODUCTION

Proximal humerus fractures (PHF) are common fractures and are the third most common type of fractures among older adults. The most commonly used implants include the locking plate and the locking intramedullary nail. Areas covered: The aim of this study is to perform a literature review of biomechanical and clinical studies that compare the locking plate and intramedullary nail for PHF osteosynthesis. Expert commentary: Twelve clinical studies and seven biomechanical studies were identified that met this criterion. The findings of this review showed that intramedullary nailing and locking plate fixation yielded similar functional results, but with contrasting complication rates. The biomechanical studies showed controversial results, with most of the studies demonstrating better biomechanical properties for the intramedullary nail. Different types of intramedullary nail for PHF have different characteristics, with curvilinear nails presenting a higher risk of complications.

Management of Acute Proximal Humeral Fractures

Proximal humeral fractures, which typically occur in elderly persons, are among the most common fractures. A myriad of nonsurgical and surgical treatment options exist for these injuries, including short-term immobilization and early physical therapy, percutaneous fixation, plate osteosynthesis, intramedullary nailing, hemiarthroplasty, and reverse shoulder arthroplasty. The choice of treatment depends on the fracture type and severity, surgeon expertise, patient age, and patient health status.

Locking intramedullary nails compared with locking plates for two- and three-part proximal humeral surgical neck fractures: a randomized controlled trial

BACKGROUND

Previous studies have shown good clinical results in patients with proximal humeral fractures (PHFs) treated with locking intramedullary nails or locking plates. Our study compared the clinical and radiographic outcomes in patients with 2- and 3-part surgical neck fractures.

METHODS

In this prospective, randomized controlled trial, 72 patients with 2- or 3-part surgical neck PHFs were randomly assigned to receive fixation with locking intramedullary nails (nail group) or locking plates (plate group). The primary outcome was the 12-month Constant-Murley score. The secondary outcomes included the Disabilities of the Arm, Shoulder and Hand score, the visual analog scale pain score, the shoulder passive range of motion, the neck-shaft angle, and complication rates.

RESULTS

There was no significant mean treatment group difference in the Constant-Murley score at 12 months (70.3 points for the nail group vs. 71.5 points for the plate group; P = .750) or at individual follow-up assessments. There were no differences in the 3-, 6- and 12-month Disabilities of the Arm, Shoulder and Hand scores, visual analog scale scores, and range of motion, except for the medial rotation at 6 months. The neck-shaft angle was equivalent between the groups at 12 months. There were significant differences over 12 months in total complication rates (P = .002) and reoperation rates (P = .041). There were no significant differences for the rotator cuff tear rate (P = .672).

CONCLUSION

Fixation of PHFs with locking plates or locking intramedullary nails produces similar clinical and radiologic results. Nevertheless, the complication and reoperation rates were higher in the nail group.

Internal fixation of osteoporotic fractures

Osteoporosis leads to bone fragility and increased risk of fracture. Despite advances in diagnosis and treatment, the prevalence continues to rise. Osteoporotic fracture treatment has a unique set of difficulties related to poor bone quality and traditional approaches, and implants may not perform well. Fixation failure and repeat surgery are poorly tolerated and highly undesirable in this patient population. This review illustrates the most recent updates in internal fixation, implant design, and surgical theory regarding treatment of patients with osteoporotic fractures.

Biomechanical analysis of subpectoral biceps tenodesis: effect of screw malpositioning on proximal humeral strength

BACKGROUND

Humeral fracture after subpectoral tenodesis of the long head of biceps tendon (LHB) is a rare but devastating complication.

PURPOSE

To determine whether malpositioned (laterally eccentric) tenodesis screw placement has an influence on humerus strength reduction compared with central placement.

STUDY DESIGN

Controlled laboratory study.

METHODS

Two groups, each consisting of 10 matched pairs of human humeri, were used for this study. Biceps tendons were fixed subpectorally with 8-mm screws in unicortical 8-mm sockets. In the first group, the socket was placed concentrically in the bicipital groove and the tendon was fixed with an interference screw. In the second group, the socket was malpositioned 30% eccentrically to the lateral (tension) side of the humerus. Contralateral humeri remained intact as positive controls. Specimens were aligned in 40° of abduction, and a uniaxial compressive force was applied to the humeral head until failure. Strength reduction was reported as percentage reduction in ultimate failure load between paired humeri. Relative defect size was calculated as a percentage of the total humeral width at the height of the tenodesis.

RESULTS

Laterally eccentric malpositioned biceps tenodeses significantly decreased humeral strength compared with intact (mean change, -25%; SD, 23%; P=.017), while concentrically placed biceps tenodeses did not (mean change, -10%; SD, 15%; P=.059). A linear regression between relative defect size and strength reduction in the malpositioned group showed a significant negative linear correlation (beta=-2.577; R2=0.423; P=.042).

CONCLUSION

Humeral fracture after subpectoral tenodesis of the LHB is a complication that may be minimized with careful surgical technique. Laterally eccentric malpositioned biceps tenodesis caused significant reduction (25%) in humeral strength, which might be clinically relevant and contribute to postsurgical humeral shaft fracture. Strength reduction was also significantly correlated with relative defect size. Surgeons using this technique should ensure central and orthogonal placement of the socket, especially in smaller individuals. This study lends biomechanical evidence to support the clinical procedure of a correctly, concentrically placed tenodesis screw.

CLINICAL RELEVANCE

These biomechanical results indicate that in a clinical setting, special attention should be drawn to patient selection for LHB tenodesis. This study reveals that central screw positioning is critical, particularly in high-impact and overhead athletes, as well as for patients with small humeral widths or osteoporotic bone quality. Alternative surgical options such as smaller screws or other fixation methods might be considered to diminish the postoperative risk of humeral fracture.

Indications and limitations of the fixator TGF "Gex-Fix" in proximal end humeral fractures

The incidence of fractures of the humerus has increased exponentially in recent years. The most used classifications for humerus fracture are morphological (Neer), biological (AO/ASIF) and descriptive (Hertel). The types of surgical treatment for humerus fracture include prosthetic replacement and synthesis using different devices, including the Tension Guide Fixator (TGF), Gex-Fix. External fixation for displaced proximal humeral fractures avoids dissection and soft tissue stripping and has been reported by some authors to be associated with higher union rates, a lower incidence of avascular necrosis, less scarring of the scapulohumeral interface, and faster rehabilitation compared with open reduction and internal fixation. Other authors have reported that external fixation does not ensure acceptable reduction and fracture stability, particularly in patients with osteoporosis. The external fixation technique involves the introduction of Steinmann's pin to keep manual reduction, the introduction of two K-wires in the humeral head, the removal of the Steinmann's pin, and the introduction of two fiches on the humeral shaft. Hub connectors are mounted on the wires and on the chips to connect the outer bar and tensioning system. A total of 84 patients aged 42-84 years with proximal end humeral fractures (66% had two-part fractures) were treated with Fixator TGF in this study from December 2007 to June 2012. The postoperative recovery was earlier and the active-assisted motion was less painful than has been reported with other surgical techniques. The TGF was removed without anaesthesia at the outpatient clinic at a mean of 7 weeks (range 5-8 weeks) after surgery, and there was no loss of reduction or secondary displacement after removal. These results, after five years of experience, confirm that the best indication for this fixator is two- or three-part fractures because the device enables early active mobilisation. The limitations of this fixator are evident in fractures in which closed reduction is not possible and in three-part fractures with varus displacement because the TGF has less stability than other systems, such as the plate or cage. The short learning curve, reduced surgical time and risk, and low cost encourage the use of this technique.