The anterior approach has been widely used in upper limb surgery. It is considered a valuable option in the treatment of proximal radius fractures, reconstruction of the distal biceps tendon, resection of anterior elbow tumor, and soft tissue infection. According to the mechanism of injury, after the occurrence of elbow fractures, the bone fragments often dislocate to the coronal plane. However, due to the anatomical characteristics of the anterior elbow joint, surgeons often avoid the anterior approach due to fear of damage to the neurovasculature and often choose the lateral approach, which makes it difficult to look directly at and address the fracture surface[12, 13]. With the gradual understanding of the anatomical relationship of the elbow joint by clinicians and the development of microsurgical techniques, the anterior approach is increasingly used in the treatment of elbow fractures.
Elbow joint fracture is an intra-articular fracture, and anatomical reduction of the articular surface is the key factor to achieving strong fixation and a satisfactory elbow joint[14, 15]. Adequate exposure of the articular surface is a prerequisite for anatomical reduction of fractures. Some scholars compared the exposure area of the distal humerus articular surface by different surgical approaches and found that the average percentages of exposed articular surfaces by anterior and posterior olecranon osteotomy and medial and lateral approaches were 45.7% ± 2.0%, 53.9% ± 7.1%, 20.6% ± 4.9% and 28.5% ± 6.3%, respectively. We concluded that the anterior and posterior approaches are more adequate than the medial and lateral approaches for intraoperative articular surface exposure in the treatment of distal humerus fractures. Yang et al. compared the exposure area of the coronoid process fracture between the biceps tendon-brachial artery interval (B-B interval) and brachial artery-median nerve interval (B-M interval) from an anterior approach, and the results of this study showed that the average exposed surface area of coronoid process was 2.26 times greater with the B-M interval compared with the B-B interval, allowing visualization for fracture reduction. The above study fully illustrates the theoretical feasibility of using an anterior approach to treat coronal plane elbow fractures.
Compared with other approaches, the anterior approach has some advantages[1, 6, 9]: (1) providing excellent visualization of and the most direct access for fractures in the coronal plane (Fig. 3c); (2) allowing anatomic reduction of the fracture and more fixation options, as anterior to posterior compression is more mechanically appropriate, which reduces the risk of fracture fixation failure (Fig. 3b); (3) avoiding a large amount of soft tissue dissection; (4) avoiding damaging the flexor-pronator muscle mass and the ulnar nerve; and (5) exploring the ulnar collateral ligament of the elbow joint and repairing the anterior joint capsule, which is beneficial to the stability of the elbow joint and reduces the occurrence of heterotopic ossification.
Our point of view is that it is not appropriate to directly choose the surgical approach without considering the type of fracture. One of the rules of classifying fractures is to better understand the mechanism of injury and local anatomical characteristics and then provide guidance for treatment. Scientific surgical protocols should not be limited to absolutely identical patterns, and the surgical approach should be individualized according to the patient's injury.
Since most elbow joint coronoid fractures are displaced forward, as long as the elbow joint is unstable, anterior surgery can be considered[16, 17]. The Kocher approach is commonly used in the treatment of the radial head, which is accessed from the extensor carpi ulnaris and the anconeus interval. It is primarily indicated for the repair of radial head fractures and lateral collateral ligaments, but there are a certain number of patients who have a combined coronoid fracture along with the presence of a radial head fracture. In such cases, the use of the lateral access route is obscured by the radial head, which makes the operating space narrow. There are even doctors who treat coronoid fractures after osteotomy of the radial head. This method causes damage to the stability of the elbow joint and additional trauma, which is difficult for patients to accept. The radius itself has intraoperative rotatable properties, so even radial head fractures that occur laterally in the sagittal plane can fully expose the fracture surface when using the anterior approach.
The posterior approach provides the greatest exposure of the distal humeral articular surface for surgery for distal humerus fractures. However, nonunion in 30% of patients is a common complication of this approach[20, 21], along with a larger surgical incision and prolonged operation time. Due to the presence of an anatomical structure in the distal humerus that is tilted approximately 30° anteriorly, the advantage of the anterior approach allows internal fixation under direct vision. Therefore, the anterior approach is recommended for AO type B fractures that mainly occur on the coronal plane, including the capitulum, trochlea, or combined fractures.
The terrible triad of the elbow is an incapacitating injury entailing posterior dislocation and fractures of the radial head and coronoid and is also often associated with a collateral ligament injury. Traditional treatment is usually a combined medial-lateral approach. However, it is worth considering that the occurrence of the terrible triad is posterior dislocation of the elbow joint caused by violence, along with forced anterior displacement of the radial head and coronoid process by the distal humerus. In terms of the injury mechanism, "smooth" reduction under direct vision by the anterior approach will bring advantages that other approaches cannot achieve. Some of the cases included in this study involved the terrible triad, and all were treated by the anterior approach with good results (Fig. 6).
Concerning complications, the serious neurovascular injury that many scholars worry about did not occur. Only two patients experienced transient postoperative median nerve paralysis, and the symptoms disappeared after regular oral administration of nutritional nerve drugs and did not recur in subsequent follow-up. There was only one case of mild heterotopic ossification in the front of the elbow joint, which was not found to bring subjective symptoms to the patient or affect the movement of the elbow joint during the follow-up process, so it was not treated. Some scholars worry that injuring the brachialis will increase the incidence of heterotopic ossification. To reduce the occurrence of heterotopic ossification, one may choose not to cut the brachialis longitudinally and choose to expose the fracture end after distraction at its edge. Since there was no additional osteotomy, as in the posterior approach, we did not observe the occurrence of nonunion. The most common symptoms were pain and limitation of motion. For patients with significant pain, timely drug analgesic treatment was administered, and significant relief was obtained within a period after surgery. A considerable number of patients with postoperative limitation of motion experience fear, and it is effective to provide active rehabilitation guidance to such patients after surgery.
Based on the study results and long-term clinical practice, we summarized some noteworthy points regarding the anterior approach for the treatment of fractures of the elbow in the coronal plane:
(1) Intraoperative elbow flexion of 5° to 10° is beneficial to reduce muscle tension while allowing the sliding of vascular nerves between loose tissues and reducing the risk of vascular nerve injury.
(2) Since the deep fascia below the external epicondyle of the humerus penetrates the lateral antebrachial cutaneous nerve, the lateral side of the incision should be within 1.5 cm of the outer edge of the biceps tendon. It may be necessary to cross the cubital crease. In that case, the surgical incision should be selected in the position above the cubital crease to prevent the possibility of postoperative scar contracture affecting elbow joint activity, as the lateral antebrachial cutaneous nerve in this area is located in the deep layer and is not easily injured during surgery.
(3) When the biceps aponeurosis needs to be cut, it can be picked up with a vascular clamp and propped open, and then a scalpel can be used to reverse the cutting to avoid damage to the brachial artery and vein and median nerve below. In addition, the traction of the nerve should be gentle.
(4) In the treatment of coronoid fractures, interval access between the brachial artery and the median nerve is chosen for the anterior approach, whereas interval access between the median nerve and the pronator interval is high risk because of the nerve branches here. The advantages of this approach are that it is safer to enter from the vascular-neural interval; it directly exposes the fracture site and facilitates reduction; it also facilitates fixation with a plate and causes less tissue damage; the disadvantage is that the medial coronoid process cannot be fixed.
(5) Care needs to be taken when exposing the radial head, over which a deep branch of the radial nerve migrates across the Frohse arch as the posterior interosseous nerve. To avoid injury to the radial nerve, the radius needs to be rotated extremely posteriorly, the termination point of the posterior rotator muscle needs to be separated, and the joint capsule is pushed from the inside out with an osteotome. Simultaneously, using the characteristics of the radius, the radial head fracture area was rotated to the surgical field for exposure.
(6) Intraoperative placement of drainage is essential, and adequate drainage prevents hematoma formation and reduces the risk of infection and heterotopic ossification.
(7) Early rehabilitation activities are recommended for patients. One of the details here is that the elbow joint should not be bandaged too much, as a thick sterile dressing will greatly affect the arc of elbow bending.
(8) To prevent heterotopic ossification after surgery, it is recommended that patients take oral nonsteroidal anti-inflammatory drugs such as indomethacin for six weeks; those with severe gastrointestinal reactions can take etoricoxib instead.
There were a few shortcomings in this study. The study was essentially retrospective, and there was no control group for comparison. Furthermore, the sample size of the different fracture types included in the study was smaller. A final problem is that this study did not analyze the combined fractures separately from the simple fractures, which will be studied separately in the future when the sample size is sufficient. Future work may also explore the efficacy of the anterior approach in the treatment of the terrible triad based on prospective studies with expanded sample sizes.