Plate Fixation of Proximal Humerus Fractures: How to Get It Right and Future Directions for Improvement

Abstract

Purpose of Review

Open reduction and internal fixation with locking plates (ORIF-LP) has been used for decades for the surgical management of proximal humerus fractures. Despite good outcomes have been widely published in the literature, unacceptably high rates of complications (up to 40%), many of them yielding poor outcomes and requiring reoperation (up to 25%), have also been reported, especially in elderly patients. Most common complications are related to implant failure, with intra-articular screw penetration as the most frequent and devastating.

Recent Findings

Advances in patient selection and surgical technique, and implementation of bone or cement augmentation, have been developed to hopefully decrease complication rates. Mayo-FJD Classification offers prognostic information that can aid in the decision-making process for proximal humeral fractures. Displaced valgus impacted fractures seem to be associated with well over a 10% rate of avascular necrosis after ORIF-LP. A principle-based and stepwise surgical technique combining anatomic reduction and a short screw configuration can provide good outcome in most patients, even the elderly, decreasing implant failures to less than 10%. Acrylic cement augmentation has the potential to further decrease implant failure rate to 1%. Reoperation rates are higher partly due to the need to remove hardware for painful subacromial conflict. However, no studies to date definitively demonstrated the superiority of ORIF-LP compared to non-operative treatment, intramedullary nailing, or reverse shoulder arthroplasty.

Summary

ORIF-LP can provide good results for the surgical management of displaced proximal humerus fractures even in elderly patients provided adequate patient selection and a principle based and stepwise surgical technique, supplemented with bone graft or acrylic cement when needed. Poor outcomes and high complication and reoperation rates should be expected when these recommendations are not followed.

Introduction

Proximal humerus fractures are the second most frequent fracture of the upper limb after distal radius fractures, accounting for 10% of all fractures in patients older than 65-year-old, and 17.5% of all osteoporotic fractures in postmenopausal women over the age of 50 [1]. The incidence of this injury continuously increases with age, with a mean age of 77 years and a peak incidence in women older than 80 [2]. Recent studies in European populations have shown that up to 50% of proximal humerus fractures meet displacement criteria according to Neer [3–5], and the older the patient, the greater the probability of suffering a displaced fracture [6]. Furthermore, older age and worse initial displacement correlate with the probability of further fracture displacement and settling during fracture healing [5, 7]. For all these reasons, older patients oftentimes present with severe fractures and poor bone quality.

Fracture pattern and fragment displacement are associated with loss of function and impairment [5]. Consequently, over the last few decades, efforts have been made to improve our ability to either surgically restore the normal anatomy with open reduction and internal fixation of severely displaced fractures, or replace the shoulder joint with an anatomic or reverse arthroplasty for those injuries judged unfixable or with a high risk of avascular necrosis. However, the precise role of surgery as opposed to conservative treatment for these injuries is still debated [8, 9•].

Our preferred method for internal fixation of the proximal humerus relies on modern low-profile locking plates (ORIF-LP). Open reduction allows direct visualization and manipulation of the fracture fragments for anatomic reduction and facilitates a correct positioning and orientation of the fixation device. Modern locking plates provide multiple points of fixation, work as a fixed angle device, and allow the possibility of using supplementary stabilization techniques, as sutures trough the rotator cuff and holes on the plate, intramedullary bone graft augmentation [10], or augmentation of the screw-bone interface with acrylic or ceramic cement introduced through cannulated locking screws [11]. All of these features are intended to decrease fixation failure, which has been reported to approach 40% in patients over 60 years old [12].

Multiple studies have documented various failure mechanisms after ORIF-LP for proximal humeral fracture, including screw back-out, screw cut-out, screw intra-articular penetration, loss of reduction, mal-reduction, malunion, and nonunion [12–16, 17•, 18–24] with higher failure rates in elderly patients [12, 25–27]. These findings, along with the lack of clinical evidence favoring ORIF-LP over conservative treatment, have shifted proximal humeral fracture treatment of displaced proximal humerus in elderly people to either conservative treatment or reverse shoulder arthroplasty [28•]. However, the outcome of locking plate fixation for proximal humerus fractures can be substantially improved with the correct patient selection, the adoption of specific fixation principles and a step-wise surgical technique with augmentation when needed [29–31]. This may be easier to accomplish concentrating these procedures in the hands of surgeons with specific training in this technique [22–27, 28•, 29–31, 32•, 33].

Indications for Locking Plate in Proximal Humeral Fractures

We based our treatment decision making for proximal humeral fractures on the Mayo-FJD classification system by trying to answer three main questions [5, 34]. In Mayo-FJD classification system, the fracture pattern is identified first, and only then displacement criteria are applied to each of the patterns, separating fracture pattern from fracture displacement. Fracture patterns are listed in Table 1 and represented in Fig. 1. These are the three key questions:

Table 1.

Mayo-FJD classification system. Fractures with neck or head involvement may include greater tuberosity, lesser tuberosity, or both tuberosities fractured

Mayo-FJD classification system
Isolated tuberosity
• Isolated greater tuberosity (GT)
• Isolated lesser tuberosity (LT)
Neck involvement
• Varus posteromedial impaction (VPM)
• Valgus impaction (VL)
• Surgical neck (SN)
• Disengaged neck (DN)
Head involvement
• Head dislocation (HD)
• Head split (HS)
• Head impression (HI)

Fig. 1.

Mayo-FJD Classification for proximal humeral fractures. IGT: isolated greater tuberosity. VPM: varus posteromedial impaction. SN: surgical neck. VL: valgus impaction. HS: head split. HI: head impression. DN: disengaged neck. HD: head dislocation

1. Is the fracture pattern such that the humeral head is fractured and dislocated (HD), severely compressed (HI), or fractured in two or more pieces (HS).

   If the answer is yes, surgical treatment is necessary.

2. Are the shaft and the head completely disconnected with no stability between the head segment and the shaft? Independent of other fracture features or tuberosity involvement, this fracture pattern is considered a disengaged neck fracture pattern (DN), and surgery is also usually indicated to avoid nonunion.

3. If the two prior questions are answered negatively, most fractures would be expected to heal with some degree of malunion. The next question is then whether the severity of the malunion will translate in pain or poor function, or if the fracture pattern is very likely to lead to avascular necrosis. The decision to proceed with surgery or not will also depend on age, comorbidities, and expectations [34]. However, as a general rule, we treat isolated tuberosity fractures with osteosuture [35]. For the rest of fracture patterns, when displaced, in patients under 65 or physiologically young, we try our best to proceed with ORIF-LP, whereas in older patients with the decision to proceed with ORIF and reverse depends on our ability to achieve a satisfactory reduction and the likelihood of extensive avascular necrosis (head dislocation, severe valgus displacement of the head) [36•]. When ORIF-LP is selected in the elderly, fixation is augmented with either structural bone graft or acrylic cement.

Locking Plate Osteosynthesis Technique

Preoperative planning includes plain X-rays with Grasey’s AP and Y scapular views. Unless the fracture is a simple displaced surgical neck fracture with clear evidence of no tuberosity or head involvement, a computed tomography is routinely obtained as well. The fracture pattern according to Mayo-FJD Classification is identified first. Then, the exact orientation of the articular surface and its integrity is checked, with special attention to anticipate the intra-operative reduction maneuvers that will be needed for head reduction. Lastly, the tuberosities are checked for integrity, displacement, its spatial relation with the head segment, and the presence of articular fragments attached to them. The fracture plane dividing tuberosity fragments is also identified, usually at some point in the anterior half of the greater tuberosity.

Table 2 further describes the criteria we use to consider a fracture to be fixable. These criteria include both preoperative findings in imaging studies and intraoperative considerations as well. Therefore, it is important to highlight the need of having available a shoulder arthroplasty system in the operating room in case intraoperative conversion to arthroplasty is needed. In our experience, in patients sustaining proximal humeral fractures with recognizable patterns, the rotator cuff is usually intact or at the most presents small repairable tears even in extremely old patients. We reason that patient with a cuff intact shoulder suffer a fracture whereas patients with a cuff-deficient shoulder are most likely to suffer a dislocation with the same injury. When a non-recognizable fracture pattern is seen, especially in the presence of extensive comminution or calcifications in the tuberosity area, an associated rotator cuff tear should be suspected, and the necessity of reverse shoulder arthroplasty anticipated. The need for enhanced fixation with structural graft or cement augmentation is determined prior to surgery, based on age and bone quality as mentioned before.

Table 2.

Characteristics of a physically repairable Proximal humeral fracture (amenable for open reduction and stable fixation)

Fixable proximal humeral fracture criteria
• Rotator cuff
- Intact or with minor repairable ruptures
- Strong as to hold traction sutures
• Tuberosities:
- At least one large piece containing cuff attachment in each tuberosity
• Head:
- < 2 mm of articular gaps or steps are present in the articular surface - At least 15 mm of cancellous bone preserved in the synthesis area for at least 4 cemented screws or 20 mm for at least 6 non cemented screws
• Diaphysis-Head relationship
- Anatomically reducible head, with adequate support in the calcar area
- A provisional stable reduction can be achieved during the procedure (wires and sutures)

ORIF-LP is a challenging and difficult operation. Following specific fixation principles (Table 3) and performing a step-by-step surgical technique (Table 4) are paramount to minimize implant related complications and obtain good clinical results [32•, 34].

Table 3.

Principles of proximal humerus locking plate fixation. Please see text for further explanation

Principles of proximal humerus locking plate fixation
1. Anatomic reduction and provisional fixation before definitive synthesis
2. Axial plate placement with reference to the humeral head
3. Maximize the number of screws engaging the head segment
4. Use of a short screw configuration
5. Selective bone graft/cement augmentation

Table 4.

Proximal humeral locking plate fixation surgical steps

Step-by-step ORIF-LP surgical technique
1. Modified deltopectoral approach
2. Tuberosity location and control with traction sutures
3. Anatomic head reduction and provisional fixation (threaded wires)
a Selective structural bone grafting
4. Anatomic tuberosity reduction and definitive fixation (cerclage sutures)
5. Plate positioning and screw fixation
b Selective cement augmentation

Principles of Proximal Humeral Fracture Locking Plate Fixation

1. Achieve anatomic reduction and adequate provisional fixation before plate positioning; this is paramount to minimize the possibility of loss of reduction during plate fixation [17•, 37•, 38, 39]. Threaded wires from the anteromedial head to the posterior shaft and tuberosity osteosuture are necessary in most cases to securely maintain the reduction.

2. Axial plate placement with reference to the humeral head. Plate positioning determine screws trajectory and final screw location. The plate should be not too high to avoid subacromial impingement, but not too low to allow adequate insertion of calcar screws to get inside the head. In addition, the plate must be centered in the sagittal plane so that all locking screws can be directed to the head, especially the strongest cancellous bone located in the inferior (calcar) and posterior areas [39, 40•].

3. Maximize the number of screws into the humeral head: correct plate positioning will ensure the maximum number of screws can get bone purchase, increasing the strength of the fixation.

4. The use a “short screw configuration.” The length of the screws should be balanced to obtain as good bone purchase as possible, but minimizing the risk of primary intra-articular screw penetration during the procedure, and preventing secondary penetration in case fracture settling or collapse during healing [32•, 34].

5. Selective augmentation of the fixation, with structural bone graft filling the interfragmentary void and providing mechanical interference, or cement in the trajectory of the screws to improve the bone-screw interface. Both strategies have demonstrated to effectively increase the resistance to fixation failure [10, 30, 31, 32•, 37•, 41–45] and, in our opinion, all patients over 65 years, and those over 50 with a low energy fracture or diagnosis of osteoporosis should be selected for either technique, depending on surgeon´s preference and availability.

Step-by-Step Surgical Technique

The patient is placed in a table allowing a “barber-chair” position, like the classic beach chair position, but with the trunk almost vertical (approximately 70° in reference to the horizontal), facilitating the exposure of the lateral and posterior proximal humerus. The patient’s trunk is placed at the edge of the table, so the arm can be displaced freely posteriorly with shoulder extension for reduction maneuvers. The distal forearm-hand is supported by an arm holder raised not too high so that gravity can assist in recovering the length of the humerus during surgery. Fluoroscopy is positioned parallel with the table, with the arc coming from behind the patient and located over his head, so that the X-ray receptor is placed posteriorly. The orientation of the arc should allow obtaining a true anteroposterior view of the shoulder in the scapular plane, as well as an axillary view.

As mentioned, achieving specific sequential aims is mandatory to reliably achieve a stable fixation. These aims/steps are outlined in Table 4 and described below [32•].

1. Proper reduction and plate positioning requires adequate exposure of the anterior and lateral aspects of the proximal humerus, along with getting to the posterior aspect of the proximal humerus for greater tuberosity suture control and fixation. We use routinely a modified deltopectoral approach to minimize the damage to the deltoid or the axillary nerve as opposed to a deltoid split. The modification affects to the skin incision, which is performed in a straight vertical fashion at the union of the medial 1/3 and the lateral 2/3 of the line connecting the coracoid process and the posterolateral acromion (just lateral to the acromioclavicular joint). Although this approach is slightly more laborious to develop, it will help us during the full procedure, especially in the more complex moments as fracture reduction and plate positioning. The subcutaneous tissues are divided down to the deltoid, and a medial full thickness skin flap is developed until reaching the deltopectoral interval. The deltopectoral interval is then developed, and the fracture is exposed after removing any hemorrhagic bursa (Fig. 2).

2. Attention is then turned to the tuberosities for traction suture placement trough the cuff.

Fig. 2.

Combined view of fracture exposure in a 42-year-old lady after a bike fall. A Intraoperative antero-posterior shoulder view. B Surgical field after bursa and hematoma clearance, exposing the fracture segments. 1: Humeral head. 2: Diaphysis. 3: Greater tuberosity. 4: Lesser tuberosity segment, including the lesser tuberosity, the bicipital grove, and a portion of the anterior tuberosity attached; shield fracture, please see text

Three absorbable braided sutures are placed in the subscapularis, another three in the infraspinatus and one in the supraspinatus tendons just proximal to their bony attachments. In posteriorly displaced greater tuberosities, shoulder abduction and internal rotation is helpful in gaining access to the tuberosity and placement of sutures on the infraspinatus. The head fragment is then identified and the existing plane between the articular surface and the undersurface of the tuberosities is recreated if hematoma or early callus is obliterating it.

• 3.Anatomic head reduction to the shaft calcar is then performed (Fig. 3). This is the main most demanding part of the procedure. Head reduction requires fracture pattern recognition and an as exact as possible understanding of the position and orientation of the humeral head with respect to the diaphysis, the glenoid, and the acromion, to predict the necessary maneuvers for anatomic reduction. The definition of anatomic reduction (performed in surgical steps 3 and 4) is to capture the head’s subchondral bone rim between the shaft calcar inferiorly and the tuberosities anterior, superior, and posteriorly, along with entrapping the articular surface between the glenoid medially, and the tuberosities and cuff. In order to plan and proceed with the reduction, it should be recognized that as important as to handle the head to face the articular surface toward the glenoid, is to move the tuberosities and the shaft in reference to the head until an anatomic reduction is achieved; in other words, accomplishing the head reduction by directly handling the head fragment itself is usually limited by the position of the other fragments, the glenoid, the acromion, and the rotator cuff, so other fracture fragments may need to be mobilized and even disimpacted to provide space for the articular surface to rotate back to its place sliding over the glenoid. Provisional fixation with 1.6 threaded wires is then accomplished introducing them from the antero-superior part of head (at the level of the rotator interval) to the posterior shaft (Fig. 4). This location of the wires is easier to perform with a minimum superior deltoid retraction, will not interfere with plate positioning, and will provide a secure head purchase as opposed to introducing them from the diaphysis. The adequacy of the reduction is confirmed with fluoroscopy
• 4.Structural graft augmentation is performed at this moment between the head and the shaft in selected patients
• 5.The tuberosities are anatomically reduced and definitively fixed with sutures. Tuberosity mobilization is performed with the traction sutures and with the aid of blunt instruments to lever them off the head and diaphysis. Their proximal fractured bony edges are placed under the head’s subchondral bone rim, and whenever possible, adjusting its distal edges to the corresponding defect on the shaft. Infraspinatus and subscapularis traction sutures are tied together to fix the tuberosities in a cerclage-like fashion. A minimum of three sutures (6 strands) are used to maintain the tuberosities in place (Fig. 4). The adequacy of tuberosity reduction is then checked with fluoroscopy. When a lesser tuberosity is fractured and displaced (Edelson’s shield fracture [46]), osteosuture is supplemented with two partially threaded 3.5 cancellous screws from the lesser tuberosity to the posterior aspect of the proximal humerus (Fig. 5). The greater tuberosity is also commonly captured by screws through the plate.
• 6.Plate positioning and screw fixation (Fig. 5). As a general rule, the plate should not be applied until a complete satisfactory reduction has been achieved and provisionally secured to minimize fracture manipulation and hence, the risk of loss of reduction. Modern anatomic plates are pre-contoured to adapt to the lateral side of the proximal humerus in most shoulders [47]. In some instances, plate positioning and insertion first of a diaphyseal non-locking screw may help bring the shaft to the plate while buttressing the head, aligning the lateral cortex of the shaft and the proximal humerus. As mentioned before, plate positioning will determine the final trajectory and location of the screws.

Fig. 3.

Combined view of fracture reduction maneuver A blunt periosteal elevator rotating the head to slide it over the glenoid until the desire orientation is achieved. B Reduction maneuver in which the stay sutures trough the cuff are pulled to move the tuberosities toward its anatomic position, under the head subchondral bone rim, while the head is held in place with a periosteal elevator. 1: Humeral head. 2: Diaphysis. 3: Greater tuberosity. 4: Lesser tuberosity segment, including the lesser tuberosity, the bicipital grove, and a portion of the anterior tuberosity attached; shield fracture, please see text. *Stay suture tagging the posterior rotator cuff. **Stay suture tagging the anterior rotator cuff. ***: blunt periosteal elevator

Fig. 4.

Tuberosity osteosuture and head provisional fixation with wires after fracture anatomic reduction; please see text. A Fluoroscopic view. B Surgical field. 1: Humeral head. 2: Diaphysis. 3: Greater tuberosity. 4: Lesser tuberosity segment, including the lesser tuberosity, the bicipital grove, and a portion of the anterior tuberosity attached; shield fracture, please see text

Fig. 5.

Definitive Fixation fluoroscope image of A the case exposed in Figs. 2, 3, 4, and 5. B A 76-year-old lady with an ORIF-LP with acrylic cement augmentation and antero- posterior cancellous screws to fix the lesser tuberosity along with osteosutures

Placing as many screws as possible into the humeral head improves the stability of the construct, especially in regards to the inferior calcar screws [48]. However, it should be recognized the intra-articular screw penetration is a very commonly reported complication and a major reason for revision surgery in many published studies. Therefore, careful technique is mandatory at the time of screw fixation. Table 5 summarizes the screw selection and placement technique. A short screw configuration (screws 4–5 mm shorter than the measured length) has been demonstrated to decrease articular screw penetration while providing low failure rates (under 10%) [32•].

Table 5.

Technical concepts for head fixation

Definitive locking screw fixation technique
1. Drilling: use drill guide and perforate only the near cortical
2. Penetrate into the cancellous bone with the measurer until the subchondral bone is felt
3. Choose a 4 mm shorter solid screw, or a 6 mm shorter cannulated screw when cement is going to be injected trough
4. Check the length of the screw before implantation
5. Ensure the screw trajectory is that of the drill guide and the measurer
6. Special caution is taken in divergent screws: intra-articular penetration is easier and less obvious under fluoroscope. Do not cement these screws
7. Place “calcar screws” whenever possible unless it requires a too high plate position in small patients
8. Use as many head screws as possible

Acrylic cement augmentation is then performed in selected patients. The aim of cement augmentation is to increase the fixation strength of the screw threads into the humeral head, thus providing better fixation. This technique gets the procedure 10–15 min longer, but in our experience, it has decreased drastically the rate of fixation failure in elderly patients [32•]. The preferred screws for augmentation are those whose tip is located in the central part of the head, to avoid partial necrosis around the most proximal ones or peripheral cement leaking, especially frequent around the calcar screws [30, 32•, 42]. The cannulated screws for augmentation are selected in advance, inserting screws that are 6 mm shorter than the measured distance to the subchondral bone. After placing all the screws trough the plate, 0.6 mL of cement are deployed through the screws selected for cement augmentation. The screw head is cleared of cement with a wire to allow future hardware removal if it became necessary. At least two bi-cortical locking screws, in addition to the non-locking screw, are placed through the plate for diaphyseal fixation. Cement long curing time allows this part of the procedure to be performed while cement is prepared in the back table (Fig. 5).

The wound is finally copiously irrigated with saline, and the wound closed in a standard fashion, leaving the cephalic vein superficial to the muscular layer. Drains are not typically used.

Postoperative Management

The arm is placed in a sling for 6 weeks. The first post-operative day, hand and elbow range of motion and shoulder pendular exercises are implemented 3 times a day.

Assisted elevation and external rotation begin at week 2, and internal rotation at week 3. Stretching exercises are implemented at week 6 and strengthening at week 12.

Avoiding Pitfalls and Preventing Complications

ORIF of the proximal humerus with a locking plate is a demanding procedure. As it has been previously mentioned, when it is not correctly indicated, executed, or supplemented, the occurrence of implant-related complications is frequent and associated with poor outcomes and the need of revision surgery [12–16, 17•, 18–24]. In the following lines, we proceed to describe how to avoid the main pitfalls to decrease complication rates with proximal humerus ORIF-LP:

Accepting Suboptimal Reduction

Inadequate head entrapment between the glenoid the shaft, the tuberosities and the cuff is the main factor contributing to loss of fixation, as all the restrain to reduction loss will be provided only by metal screws in frail trabecular bone. In elderly patients, suboptimal reductions that cannot be improved should prompt the surgeon to convert to a shoulder arthroplasty.

Poor Plate Placement

Lack of exposure and the distal insertion of the deltoid on the humerus may compromise plate placement. The most frequent error is to place the plate both too superior and too anterior because of an inadequate lateral and distal humeral exposure; such plate position can produce subacromial impingement and will also translate to poor screw positioning into the humeral head. A relatively lateral skin incision allowing easy lateral humerus exposure, combined with selective subperiosteal elevation of the distal anterior deltoid attachment will provide adequate space for correct plate placement. In extreme cases in young muscular patients with complex fractures, an anteromedial approach [49, 50] can be considered.

Intra-operative Loss of Reduction

Achieving an anatomic reduction before plate positioning (defined in surgical step 3) and maintaining the provisional wire fixation until the end of the fixation procedure will help prevent this intraoperative complication, especially devastating once screw placement has begun. When a threaded wire is in the way of a screw, either the wire is kept and the surgeon proceeds with another screw, or an additional wire is introduced in another location before removal of the initial wire. These maneuvers are repeated until at least 4 screws are already inserted holding the head; then the wires can be definitively removed, and more screws can be inserted.

Primary Intra-articular Screw Penetration

Defined as the humeral head subchondral bone perforation, is one of the most common complications [15]. This can be avoided with the “short screw configuration” depicted in points 1 to 6 in Table 5. Intraoperative fluoroscopic assessment of the fixation in both the anteroposterior and axillary views is mandatory to rule out this complication after all screws have been inserted.

Loss of Reduction and Secondary Intra-articular Screw Penetration

Loss of reduction is associated to preoperative varus deformity, advanced age, smoking, varus mal- reduction, failure to incorporate the rotator cuff to the construct with tension bands sutures and inadequate medial support [12, 22, 51, 52•, 53–62]. Secondary screw penetration is defined as humeral head subchondral screw perforation after the surgery, because of fracture collapse/settling or loss or reduction. The entire philosophy of the principles of fixation and the step-by-step ORIF-LP surgical technique (Tables 3 and 4) are both designed to avoid this complication, and have demonstrated to decrease fixation failure even in elderly patients [32•].

Intra-articular Cement Leaking

Is avoided selecting the central screws for augmentation and avoiding the peripheral ones, especially the calcar screws as mentioned before. Technical considerations include: the drill should be used to perforate only the proximal cortex; careful penetration trough the cancellous bone with the measurer is performed to avoid perforating the subchondral bone. Cement insertion is monitored with fluoroscopy and also visually to confirm fluid coming out from inside other cannulated screws or fracture lines as cement replaces intramedullary content (If this does not happen, a cement leak should be suspected, and cement injection stopped).

Limited Avascular Necrosis Around Cemented Screws

Limited avascular necrosis has been described around the tip of screws, appearing in 4 to 7% of cases [30, 32•]. Small areas of AVN have been described particularly around the upper screws of the plate, located in the superior part of the humeral head. Currently, most recommend avoiding cement augmentation on this location, favoring cement augmentation of central head screws.

Extensive Avascular Necrosis

Cannot be stopped once it starts to develop. Therefore, prediction and prevention are the only available options, and they are both quite elusive [63•]. Extensive avascular necrosis has been reported more often in severely displaced valgus impacted fractures, as described above. In one study, extensive avascular necrosis was reported in 12% of the shoulders with this fracture pattern, 6 times more common than in varus posteromedial fractures [32•]. Consequently, we recommend avoiding ORIF-LP in these cases along with in those old patients sustaining a head dislocation.

Expected Results

When adequate patient selection and surgical technique are both performed, ORIF-LP is a valuable treatment option, with several studies reporting good to excellent outcomes after locked plate fixation [15, 16, 64–70] even at an advanced age [17•, 32•, 33, 37•]. Young patients sustaining high-energy fracture-dislocations involving the tuberosities have also reported to obtained good functional outcomes in most cases [36•]. Average elevation, external and internal rotation of approximately 120°, 40° and T11, respectively, can be expected after ORIF-LP regardless of patient of age [17•, 33, 71].

In contrast to what it has been mentioned in the previous paragraph, several recent publications have reported very high complication rates (up to 45%) and reoperation rates (11–28%). Complications were associated to fracture complexity and advanced age and could not be avoided with a fibular allograft in a study reported by Mayo Clinic. In an international multicenter study, most frequent complications were intra-articular screw penetration (23%), followed by persistent shoulder pain (16%), avascular necrosis of the humeral head (10%) and secondary fracture displacement (5%); however, those complications were significantly higher in one country as opposed to the other, highlighting the influence of patient selection and surgical technique in the outcome [72•, 73•].

In our experience, when appropriate patient selection is performed and the principles of fixation and the surgical steps are followed, the overall complication rate was 25% in a population over 65 years old, including an 8% of implant failure rate. When cement augmentation was implemented, the complication rate went down to 15%, and implant failure rate decreased to 1% [32•]. Subacromial plate impingement was the most common problem, occurring in 5% of patients; revision surgery rate was 9% with or without augmentation. Similar results have been in a separate recent publication [33].

Future Directions for Improvement

ORIF-LP is a demanding procedure with a potentially high number of complications and reoperations, but able to provide a good outcome when correctly indicated and performed. Understanding indications is paramount to advance and improve our results with this technique. As mentioned before, fracture pattern seems to be associated with outcome after ORIF-LP, and more studies are necessary to better predict outcome based on fracture pattern and displacement, along with patient functional demand, comorbidities, and expectations.

Surgical technique has also demonstrated to play a direct role in outcome. These injuries should be managed intraoperatively with a specific and sequential technique, aiming for an anatomic reduction and careful fixation, with a clear understanding of the potential pitfalls and complications. Specific education is necessary for the surgeons taking care of these injuries, including pattern recognition, reduction maneuvers, and fixation technique, along with adequate training both with cadaveric specimens and surgical volume.

Technology also plays a role in improving results. Current locking plates have not significantly evolved during more than 20 years. Advances and technical developments are needed for plates and screws, adjuvants for provisional fixation, and the instrumentation provided. Immersive 3D imaging and 3D printing, and the possibility of providing virtual surgical planning tools, including the simulation of reduction maneuvers or plate positioning, would also be of great value. Finally, artificial intelligence could help in predicting outcome for our future patients.

Better quality research is also needed in this area. Several recent articles have provided no evidence supporting ORIF-LP over the use of intramedullary nails [37•, 74, 75] or reverse shoulder arthroplasty [76••, 77]. Furthermore, none of these surgical techniques has demonstrated to overcome the results of non-operative treatment so far [8, 9•, 78, 79]. However, in our opinion, to obtain valuable and not biased evidence, we need to change the way we analyze our results. Comparisons should be performed for each specific fracture pattern and pairing cases with similar fracture displacement age and comorbidities; a standardized and reproducible surgical technique should be used in clinical trials; outcome should be compared with pre-fracture status (contralateral side range of motion and strength, and function tests obtained the day of the injury) and functional or motion loss should be the variable of comparison between treatment groups. Extreme cases (head dislocation, disengaged neck fractures) should also be taken into account when interpreting the value of surgery compared to non-surgical treatment, as they are usually excluded in these studies, giving the impression that no patients benefit from surgery. Finally, more evidence is needed regarding treatment outcome after proximal humeral fractures in young patients, with greater physical demands and better bone quality. Results obtained from comparative treatment studies performed on elderly people probably should not be extrapolated to this younger patient population, which could be more sensitive to malunion and less prone to suffer implant related complications.

Conclusion

ORIF-LP is a difficult operation. Good outcomes can be expected for many cases when properly selected and specific principles of fixation and a step-by-step surgical technique is performed, even in elderly patients. Fractures with a higher probability of avascular necrosis, such as head dislocations and severely displaced valgus impacted fractures in elderly patients are better treated with other techniques or conservative treatment. Principles of fixation include anatomic reduction and provisional fixation before plate positioning, a short screw configuration to avoid screw penetration, and cement or bone graft augmentation in all shoulders with frail bone. Potential complications are severe and frequent when these principles are not accomplished, leading to poor outcome and reoperations especially in elderly patients. Potential improvements are possible and necessary in implants and surgical technique. More evidence is necessary to confirm our own personal experience.

Declarations

Human and Animal Rights and Informed Consent

This article does not contain any studies with human or animal subjects performed by any of the authors.

Conflict of Interest

Antonio M Foruria MD PhD received economical compensation for participating as speaker or faculty in educational activities organized by Depuy-Synthes and AOTrauma in Spain and other European Countries, in which the implants included in this paper were discussed.