Fig. 25.1
Two precontoured anatomic perpendicular plates are used to fix a distal humeral fracture. In this case, the use of perpendicular plates can be indicated since the fracture does not affect the articular surface. (a, b) Preoperative x-rays, showing displaced distal humeral fracture; (c, d) Postoperative x-rays showing anatomical reduction and plate fixation
Fig. 25.2
Two precontoured anatomic parallel plates are used to fix this distal humeral fracture affecting the articular surface of the humerus. Using these plates, fractures with comminution of the articular surface can be successfully treated. (a, b) Preoperative x-rays, showing displaced distal humeral fracture with comminution of the articular surface; (c, d) Postoperative x-rays showing anatomical reduction and plate fixation
The use of one-third tubular plates is not recommended because they are too weak and prone to breakage, particularly in cases of metaphyseal comminution [18–20].
Different authors advocate the use of locking compression plates (LCPs) because they are more reliable in humeri with decreased bone quality or in the presence of a metaphyseal comminution and because they are based on the principle of an internal fixator [21]. However, even though they have been proven to achieve better fixation and outcomes when used for other types of fractures, the use of locking plates for distal humeral fractures is debated. There is a lack of evidence to recommend for or against the use of LCP. Schuster [22] used cadaver specimens of different bone mineral densities to compare the stiffness of conventional reconstruction plates, surgeon-contoured 3.5 mm LCPs, and precontoured distal humerus LCPs. Results were not significantly different between the three groups even though the failure rate was lower in the precontoured distal humerus plate group. In particular, there was no statistical difference between LCPs and conventional reconstruction plates, but the author concluded that, in case of low bone density, LCPs should be chosen over other hardware. Korner [23] showed no difference in stiffness between LCPs and non-locking conventional reconstruction plates placed in a perpendicular configuration. Reising [24] and Greiner [25] reported good results, but the evidence level of their studies is type IV. Other authors prefer not using LCP to prevent the problem of incorrect screw positioning due to the fixed angles of the hardware [26, 27].
Quite recently, implant manufacturers have started producing specially precontoured distal humeral plates. Despite being more costly, these plates are preferable since they may reduce the duration of surgery and since their fracture-specific screw patterns allow high-density screw placement into the distal humeral articular segment [22, 24, 28]. Low distal humerus fractures with articular comminution seem to be best treated with precontoured plates [29]. Athwal [28] reported the results of 32 patients affected by AO C-type fractures treated with precontoured non-locking plates. He stated that a high rate of union with good outcomes can be expected but was also concerned about the high rate of complications (a total of 24 complications occurred in 17 patients, including nerve injuries, wound problems, and intra-articular screw penetration). Celli [30] reported excellent and good results achieved in 16 patients and unsatisfactory results in 2, but the study was a retrospective, multi-surgeon series with a relatively short follow-up period. Theivendran [31] reported good functional results and a high union rate but pointed out that screw extraction can be difficult when the implant is removed. Contrary to this, Koonce [32] stated that perpendicular conventional reconstruction plate constructs provided similar stiffness and load to failure properties to precontoured locking plate systems regardless of plate configuration.
Finally, plate length is also important: plates should end at different levels proximally to avoid the formation of a stress riser in the humeral diaphysis [26].
Key Point
Precontoured anatomic plates seem to provide better outcomes through superior biomechanical properties.
25.3 How Many Plates?
It is now widely accepted that good fixation requires two plates, either parallel or perpendicular [11, 18, 33, 34]. In distal humeral fractures, one plate is usually not enough to guarantee good stability, while in other fractures (e.g., proximal tibia and distal femur) the introduction of LCPs has obviated the need for bicolumnar fixation. The use of a single lateral plate should be avoided or limited to well-selected cases where the fracture does not affect both the lateral and medial columns of the distal humerus.
Some clinical studies reported adequate fixation of extra-articular distal humerus fractures using a single-plate technique [4, 35, 36], but some degree of cortical contact was present, and this probably influenced the outcome. Tejwani [37] performed a biomechanical study to compare the stiffness and the strength provided either by standard double-plate fixation or by single-locking plate fixation in cases of comminuted extra-articular distal humeral fractures. The first construct was significantly stiffer than the second in anterior bending, posterior bending, and lateral bending, while there were no significant differences in axial compression and torsion.
However, different results have been recently reported by Meloy [38]. The authors compared the traditional dual-column plating with a single-column posterolateral small-fragment precontoured locking plate used as a neutralization device with at least five screws in the short distal segment in fracture extra-articular cases (AO A2 and A3 types). The two groups had similar union rates and alignment, but the second was characterized by a better range of motion with less complications.
A third posterolateral plate may be used to increase the fixation rigidity [39, 40]. Some authors believe that it is mainly indicated for low transcondylar fractures and those with a coronal shear component, which are best stabilized using posterior to anterior screws [34].
Key Point
Two plates either parallel or perpendicular are preferred to a single-plate configuration.
25.4 Which Plate Configuration?
Three options of plate localization have been described:
Perpendicular plating (Fig. 25.1): This technique evolved after a publication by Jupiter in 1985 [41]; the posterior plate is the lateral one. It needs to be placed as close as possible to the capitulum articular surface without causing impingement, so that it can gain the best possible purchase of its screws in the distal fragment.
Parallel plating (Fig. 25.2): This concept was conceived because some surgeons felt that the orthogonal plating technique provided inadequate fixation of the distal fragments and not enough stability between the intra-articular distal fragments and the humeral shaft [14, 19, 42–44]. Based on these observations, the Mayo Clinic group proposed the idea of parallel plating [33, 45]. The lateral plate is applied along the supracondylar ridge in the sagittal plane and is characterized by a “J” shape to accommodate the anterior angulation of the lateral epicondyle; it needs to be placed as distal as possible to the edge of the capitulum. The surgeon must evaluate the elbow in full extension and pay attention that the plate does not impinge on the radial head. The medial plate is placed along the supracondylar ridge that curves around the medial epicondyle; it is better if distal tip of the plate lies superior to the most prominent portion of the medial epicondyle. Actually, the two plates are not perfectly parallel, rather they are offset dorsally such that the angle between them is usually between 150° and 160°. This allows the placement of at least four long screws passing through the distal fragments from medial to lateral and vice versa [46].
Triple plating : It is a combination of the two techniques. It is used in cases with severe comminution where additional fixation is required. Typically, the third plate is applied along the lateral aspect of the lateral column [47, 48]. However, it does not seem to confer greater stiffness and is technically difficult [34].
To date, the first two plate configurations have typically been used. Historically, the treatment with conventional reconstruction plates in a perpendicular configuration has been recommended by the AO group [49, 50]. However, this approach has been widely criticized—mainly because obtaining adequate screw purchase and length in a posteroanterior direction through a posterolateral plate can be difficult (especially with osteopenic bone) [51]. Several studies support either the parallel plating technique [28, 30, 31, 52, 53] or the orthogonal plating technique [24, 25, 54–56].
25.4.1 Studies Supporting the Parallel Configuration
Schemitsch [18] created a metaphyseal supracondylar osteotomy to reproduce a distal humeral fracture in eight upper extremities from cadavers. He then created a gap and tested the plate reconstruction with and without cortical contact. In the former configuration, the plates provided equivalent rigidity, while in the later configuration, the parallel plates showed higher stiffness in axial compression, without any difference in ultimate load to failure.
Zalavras [57] stressed the fact that the fracture model used in his study was characterized by an extensive metaphyseal defect for which he used, in contrast to previous studies, plates from a single elbow fixation system in order to avoid bias. Screw loosening occurred in all posterior plates of orthogonal constructs but in none of the parallel plate constructs.
Arnander [58] osteotomized two groups of artificial humeri. The specimens were subject to static loading only in the sagittal plane in an anteroposterior direction, and the parallel system had superior strength and stiffness as compared to the orthogonal system.
Stoffel [59] tested on cadavers two elbow plating systems with locking screws (the perpendicular 3.5 mm LCP distal humerus plating system and the parallel Mayo Clinic Congruent elbow plate system). They were tested for their stiffness (in compression and internal/external rotation), plastic deformation, and failure in torsion and showed that the parallel construct had significantly higher stiffness in axial compression and external rotation than the orthogonal construct. However, the different plating systems might be a confounding factor.
In Penzkofer’s biomechanical study [60], three different implant configurations on artificial humeri were compared to each other: parallel plating and orthogonal plating either with a posteromedial plate or with a posterolateral plate. All three plate configurations provided enough mechanical stability to start early postoperative rehabilitation; the parallel configuration achieved the highest bending stiffness in extension, while in flexion the highest bending stiffness was provided by the construct with a posterolateral plate. However, the author concluded that a parallel plate configuration provides the highest stability since extension is the most demanding load situation for the elbow.
25.4.2 Studies Supporting the Perpendicular Configuration
One of the first studies evaluating the perpendicular configuration was carried out by Helfet [61], who stated that it was biomechanically optimal. However, he compared this construct with cross screws or the single “Y” plate.
Jacobson [34] evaluated the rigidity of five internal fixation constructs. There was no significant difference in torsional stiffness of the five constructs. The configuration with a medial pelvic reconstruction plate combined with a posterolateral dual compression plate had significantly greater relative bending stiffness in the sagittal plane than the other constructs. However, this difference could be a consequence of the stronger plate used in the orthogonal group and as opposed to the plate orientation.
Got [62] evaluated bone density of ten pairs of cadaver elbows and randomly assigned them to either the parallel or the perpendicular configuration group. These two constructs were tested in cases of comminuted intra-articular fractures. He demonstrated that the two constructs had similar biomechanical properties, while the perpendicular configuration had greater torsional resistance.
25.4.3 Studies Showing No Difference Between the Two Options
Kollias [63] compared in a cadaveric study precontoured non-locking parallel plates versus a 90° non-locking construct. He found a trend toward more stiffness of the parallel construct in anteroposterior, mediolateral, and torsional testing, but statistical significance was not achieved. He concluded by suggesting both configurations but stressing that his results were in line with the biomechanical literature supporting the use of a parallel configuration.
Schwartz [64] created a bicolumnar fracture in ten artificial humeri: five were randomly fixed with parallel plates and the other five were fixed with orthogonal plates. Both configurations seemed to provide similar stabilization under physiological loads: there were no differences between constructs both under longitudinal strain (for torsion, varus/valgus or flexion-extension) and under transverse strain. However, this study does have some limitations, e.g., the low number of specimens and the different plate systems used.
Key Point
A parallel plate configuration seems to provide better biomechanical properties compared to a perpendicular plate configuration.
As we can see, all the references cited above are biomechanical studies . Only two clinical studies have been recently carried out.
Shin [51] described the results of 17 patients treated by perpendicular plating and 18 by parallel plating techniques. All patients were affected by closed intra-articular distal humerus fractures (AO C type) and were randomly assigned to one of the two groups. Different types of plates were used, but the material was the same (titanium). A single surgeon carried out all surgeries within 5 days of injury (except for one patient), and all patients followed the same postoperative rehabilitation protocol. In the perpendicular plating group, the arc of flexion averaged 106° ± 23° postoperatively (mean elbow flexion of 119° ± 16° and mean extension of 13° ± 9°), while in the parallel plating group the arc of flexion averaged 112° ± 19° (mean elbow flexion of 121° ± 15° and mean extension of 10° ± 8°). The Mayo Elbow Performance Scores (MEPS) were 91.5 and 94.3, respectively. Bony union occurred at 6.3 months and at 5.4 months after surgery, respectively, and nonunion was observed only in two patients of the first group. The author reported five complications in the first group and seven in the second one. Even though no significant differences were recorded between the two groups, the author concluded that the two nonunions in the perpendicular group may suggest a more rigid fixation provided by two parallel plates.
Lee [65] performed a prospective, randomized, comparative study including 67 patients affected by AO C-type intra-articular distal humerus fractures randomly divided into two groups: 32 in the perpendicular group (using a locking compression distal humerus plate) and 35 in parallel group (using a precontoured anatomic plate). All surgeries were performed by the same surgeon, and all patients followed the same postoperative and rehabilitation protocol. The operating time, the time to fracture union, the presence of a step or gap at the articular margin, the varus/valgus angulation, the functional recovery, and the complications were recorded. No articular defects >1 mm were detected. Bony union was achieved at a mean of 6.1 months in the first group and 5.8 months in the second group, and no patients were affected by nonunion. The mean arc of motion at last follow-up was 98° ± 20° versus 100° ± 23°, respectively. The VAS, DASH, and MEP scores were 2 ± 1.3 versus 2 ± 1.7, 25.2 ± 9.8 versus 22.9 ± 8.7, and 85.1 ± 28.2 versus 89.7 ± 30.1, respectively. Three patients in the perpendicular group and two patients in the parallel group experienced heterotopic ossification: one of the latter two needed resection with arthrolysis and implant removal after 11 months. Two patients with screw loosening in the parallel group had a secondary procedure; however, fracture stability was not affected. Eight patients in the perpendicular group and 13 in the parallel group required surgery to remove hardware, the main reason for which being the prominence of the olecranon plate or lateral plate in the parallel group. The author concluded that no significant differences were found between the two methods with respect to clinical outcomes and complications. Nevertheless, the perpendicular configuration may provide additional stability in cases of coronal shear fractures, while the parallel configuration may provide more stability at the most distal portion of the humerus thanks to a higher number of screws.
25.5 Authors’ Preferred Approach
A good outcome after surgical treatment for a fracture of the distal humerus is the result of the integration of several factors:
Detailed preoperative evaluation
Careful management of the soft tissues
Adequate visualization of the fracture
Proper fixation technique
Early postoperative mobilization
Detailed Preoperative Evaluation. All patients undergoing surgery for fractures of the distal humerus should be evaluated with CT scans with 2D and 3D reconstructions (Fig. 25.3).
Fig. 25.3
Accurate preoperative planning is mandatory to successfully treat comminuted fractures of the distal humerus: 2D and 3D reconstructions should be obtained in all the cases. (a, b) preoperative x-rays, showing displaced distal humeral fracture with comminution of the articular surface. (c) postoperative xrays showing anatomical reduction and plate fixation
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