Source: Journal of Clinical and Research in Orthopaedics
Authors: Zhao Sen, Zha Yejun, Gong Maoqi, Jiang Xieyuan
Olecranon fracture of the ulna accounts for about 1.17% of systemic fractures and is an intra-articular injury, so it is often accompanied by intra-articular hemorrhage and interstitial fluid exudate. Patients present with pain, swelling, and limited motion of the elbow with palpable depression at the fracture end. The most important sign of this fracture is loss of gravitational elbow extension, indicating a disruption of extensor device continuity. This sign is critical to treatment and is often clinically confirmed by x-rays. In addition, patients with olecranon ulnar fractures should be examined for nerve function in the upper extremities, particularly to rule out ulnar nerve injury. Ulnar olecranon fracture is accompanied by flexion and extension of the elbow joint, and the fracture end is easily separated and displaced, and the defect or unevenness of the half-moon notch articular surface of the olecranon notch can cause later elbow stiffness or traumatic osteoarthritis.
Good reduction and fixation of the semilunar notch during surgery is the basic principle for the treatment of olecranon fractures of the ulna. Patients with olecranon ulnar fractures that are not displaced or displaced < 2 mm may be treated nonoperatively. It is mainly suitable for nondisplaced and stable fractures, and is generally fixed with a cast or brace with 90° elbow flexion. For ulnar olecranon fractures with displacement, manual reduction alone is not easy to succeed, and complications such as ossifying myositis are easy to occur after multiple manual reductions, so most scholars do not advocate the use of manual reduction alone to treat olecranon fractures of the ulna. In addition, prolonged immobilization can cause stiffness in the elbow joint, which can affect early joint mobility. As a result, manual reduction is now less commonly used.
At present, there is little literature on the non-surgical treatment of olecranon fractures of the ulna. External fixation such as plaster cast or brace has poor effect on complex or crushed ulnar olecranon fractures, and seriously affects normal life and brings many inconveniences, so most of the ulnar olecranon fractures are treated with open reduction and internal fixation.
1. Surgical treatment of olecranon fracture of ulna ]
External fixator fixation:
In recent years, external fixation is rarely used for olecranon fractures of the ulna, and there are few related reports. The surgical operation method is generally to use K-wire to reduce the olecranon fracture of the ulna under intraoperative C-arm fluoroscopy. The K-wire is temporarily fixed, and the K-wire is removed after the external fixator is installed. The operation method is relatively simple, the intraoperative trauma is less, and the elbow joint function exercise can be performed in the early stage, but it is not widely used in clinical practice because external fixation affects life and requires long-term acupuncture nursing.
Internal fixation surgery:
Surgery is usually performed in a lateral or supine position with the forearm over the chest. The most commonly used surgical approach is the posterior median elbow approach, which is "S" shaped and the incision avoids a completely straight line that causes scarring over the tip of the elbow. The skin and soft tissues can be sequentially separated along the incision and exposed to the fracture site, the fracture end can be cleaned, and the appropriate internal fixation method can be selected. There are many types of internal fixation devices that can be used to surgically treat olecranon fractures of the ulna.
[ 1, "8" steel wire internal fixation ]
"8" wire internal fixation is a relatively primitive surgical method. The ulnar olecranon fracture is perforated horizontally, and the thin wire crosses through the bone foramen and then passes under the triceps aponeurosis at the tip of the olecranon of the ulna, and the thin steel wire is evenly pressurized to fix the olecranon of the ulna. This method has less irritation and simple operation after internal fixation. However, for fracture tension side fixation is not strong enough, postoperative cast immobilization is often required. This will inevitably affect the early postoperative rehabilitation exercises. Although "8" wire fixation rarely undergoes internal fixation removal due to internal fixation agitation, for patients with long fracture lines or comminuted fractures, the fracture end is prone to slip when the wire is compressed, and the fixation effect is not good. This fixation method is rarely used in clinical practice.
[ 2. K-wire tension band fixation ]
K-wire tension band fixation was first used in the treatment of olecranon fractures of the ulna, and has been widely used in the treatment of non-comminuted olecranon fractures of the ulna. The technique is designed to promote fracture healing by converting the tension acting on the fractured end into pressure that makes the fracture more compact. This method has the advantages of small surgical damage and simple operation. However, because the K-wire needle is not threaded, it has poor slip resistance in later functional exercises. Hume et al. believe that most of the K-wire needles are made of stainless steel, and the end of the needle is more irritating to the skin and soft tissues, which is easy to form bursitis, and if the skin is punctured, it can also cause the risk of local infection. This is the main reason why many patients require internal fixation to be removed. Therefore, when some scholars later inserted the K-wire from the proximal end of the olecranon of the ulna into the medullary cavity, the K-wire was drilled deeper into the anterior cortex of the ulna obliquely to prevent the needle from being withdrawn. Many scholars have pointed out that the cortex of ulnar olecranon comminuted fractures is incomplete. When the tension band produces dynamic compression, due to the lack of effective support, the tension band can cause the compression of the fracture end and the shortening of the long axis of the olecranon, which is easy to mismatch the semilunar notch of the ulna and the trochlear joint of the humerus, which in turn leads to complications such as traumatic osteoarthritis in the later stage. Jiang Xieyuan et al. also believe that the intact cortex is one of the basic conditions for tension band fixation of olecranon fracture of the ulna. In recent years, more and more cases have been using titanium cable as a new type of tension band to treat olecranon fractures of the ulna, and there are more research reports on the use of No. 5 Ecibang wire instead of steel wire tension band. This method can not only reduce the irritation of the surrounding tissues by the internal fixation, but also require a single incision to remove the K-wire after the fracture has healed, and the trauma to the limb is relatively small.
[ 3. Intramedullary fixation ]
Ulnar olecranon fractures were first treated with intramedullary screws, and later improved to the treatment of olecranon fractures with cancellous bone screws after popularization and development of internal fixation techniques. This method is mainly suitable for simple transverse olecranon fractures. The screws need to be strong enough to prevent breakage, and they need to be long enough to hold the distal ulnar medullary cavity firmly. The procedure involves inserting a long cancellous bone screw with a large diameter through the proximal ulna into the medulla, through the fracture line, to the distal medullary cavity. Megaro et al. believe that this method can compress the fracture end, and if the ulna olecranon fracture is severe or there is a bone defect, it will be over-compressed, resulting in a shortening of the ulna olecranon length or even a mismatch of the humeral-ulnar joint. There are also fixation methods that combine tension bands with intramedullary screw technology. The screw is screwed from the proximal end of the ulna to the medullary cavity of the distal ulna, and then fixed with a tension band and the screw head "8" after matching, so as to prevent the mouth opening trend of the dorsal fracture end of the ulna. Later, some scholars improved the technique and used interlocking compression intramedullary nails to treat patients with olecranon fracture of the ulna, with an excellent rate of 91.3%.
[ 4. Plate internal fixation ]
Common plates for the treatment of olecranon fractures of the ulna include 1/3 tubular plates, hooked plates, and anatomical locking plates. After the soft tissue is fully separated during the operation, the fracture end is cleaned under direct vision, the articular surface is reduced, and a steel plate of appropriate size is placed on the dorsal side of the ulna, which is screwed in turn. The dorsal plate fixation of the ulna can effectively prevent the fracture end from opening dorsally, which is more in line with biomechanical properties. The humeral trochlea can be used to reduce the half-moon notch surface with incalculation during postoperative exercises, and promote articular surface shaping. Patients with large coronal fractures can also be screwed with plates. In recent years, anatomical plates have been widely used to avoid excessive dissection of soft tissues at the fracture site and effectively protect local blood vessels. In severe olecranon fractures of the ulna with incomplete cortex, compression alone may result in shortening of the olecranon or insufficient fixation. If there is a bone defect, it can be fixed with a bone plate after bone grafting. This method can not only support the broken end and maintain the stability of the fracture, but also maintain the length of the olecranon of the ulna. A common complication after plate fixation is soft tissue irritation, which is more common in slender patients and can be clearly palpated under the skin.
[ 5、Memory alloy internal fixation ]
Shape memory alloys automatically return to their original shape by adjusting the temperature. The technology was initially used for industrial pipe joints and has since been used in the medical field. This dynamic process of gradual reversion can act as a stabilizing compression and balance of the triceps brachii at the ulnar olecranon fracture. Medawar et al. found that the memory alloy technology has better biocompatibility, less irritation to the surrounding tissues, and does not have the shortcomings of K-wire loosening and needle withdrawal in tension band fixation. However, the heating and rewarming of memory alloys during surgery is cumbersome and time-consuming, so this technology has not been widely used so far.
[ 6. Olecranon resection ]
This method is mainly used as one of the methods for reoperation after the failure of open reduction and internal fixation in the treatment of ulna olecranon. For elderly osteoporosis or simple olecranon fractures of the ulna that cannot be fixed by implants due to severe fractures, olecranon resection and triceps brachii insertion repair and reconstruction can be performed. Li Cheng et al. found that when the ulna olecranon tip fracture fragment is not more than 3 mm, it can be surgically removed, and when the bone loss is more than 3 mm, the elbow joint will be unstable. A simple olecranon fracture of the ulna resects 70% of the olecranon and does not significantly affect elbow stability after reconstruction of the triceps insertion. Gartsman et al. concluded that there was no significant difference in triceps isometric contraction strength between patients who used internal fixation and those who had ulnar olecranonctomy.
[ 7. Sled board technology ]
The olecranon sled, TriMed Inc. Valencia, CA is a new type of internal fixation technology developed in recent years, which can be used to treat simple fractures of olecranon or fixation after olecranon osteotomy, and effectively avoid the problems of K-wire withdrawal and internal fixation of steel plate irritating surrounding soft tissues. After the olecranon of the ulna is fully exposed during the operation, the fracture is reduced and the broken end is temporarily fixed with a K-wire. If there is a large fracture, it can be fixed with screw-assisted reduction, and the matching guide is attached to the proximal end of the olecranon with a K-wire. Use a 2.0mm drill bit to open the two pre-holes of the guide, and insert a fine K-wire needle in each of them. After removing the guide, the two reserved K-wire hollow loops of the sled wire loop are respectively inserted into the indwelling K-wire, and the K-wire ring is pushed into the proximal end of the olecranon of the ulna for fixation, and the metal gasket supporting the sled board can be stuck in the outer part of the sled, and the fracture end is pressurized with the help of the guide. Use 2 leather nails to fix the 2 holes at the proximal end of the spacer to the ulna, and do not tighten it for the time being. The semicircular hole groove at the most distal end of the gasket forms a relatively movable nail hole with the wire arc at the distal end of the sled. By the time the distal nail is screwed in, the spacer is fixed with axial movement proximal to the ulnar fracture. In the process of screwing into the bone cortex, the outer ring of the sled wire bone is further squeezed to the distal end, and then all the untightened leather nails are replaced with locking screws, that is, all fixation is completed. The olecranon sled technology is a relatively new fixation method, which combines the characteristics of tension band and steel plate fixation, and can be used for olecranon fracture and olecranon osteotomy without postoperative complications such as K-wire withdrawal and needle tail stimulation.
2. Characteristics of various internal fixation methods
At present, the most commonly used internal fixation methods are still tension belt fixation and steel plate fixation, and sled board is also a better choice. Because the K-wire penetrates parallel to the ulnar bone marrow cavity during the fixation of the tension band, many scholars tend to continue to penetrate the K-wire into the anterior cortex of the ulna during the operation to strengthen the support of the articular surface and prevent the needle withdrawal, and then combine the "8" ring wire to compress and fix the fracture end. After biomechanical research, Brink et al. concluded that the compression effect of the fractured articular surface of the elbow joint and triceps brachii was better when the elbow was contracted, and when the elbow was extended by 30°~75°, the direction of the triceps tendon and the long axis of the ulna were gradually parallel, and the pressure increased. Therefore, tension band fixation achieves fracture healing through a combination of static and dynamic compression. K-wire tension band has a good treatment effect on simple olecranon fractures, but the withdrawal and soft tissue irritation of K-wire are as high as nearly 30%. Many scholars believe that inserting a K-wire into the anterior ulnar cortex is an effective way to avoid the risk of needle withdrawal. Other scholars believe that the main reason is that the K-needle tail needle is reserved more, which is easy to cause needle withdrawal when the elbow joint is moved.
Prayson et al. found through MRI that the K-wire penetrated the anterior cortex and easily injured the median nerve and ulnar artery, and even affected the rotation of the forearm. The ulnar sled board organically combines the two methods of K-wire tension band and steel plate fixation, and there is no need to worry about the withdrawal of the needle similar to the K-wire and the damage of the needle tip to the nerves and blood vessels of the forearm when the fracture end is continuously pressurized and fixed, and the fixation stability is similar to the tension band, which is more suitable for simple ulnar olecranon fractures. At the same time, it also effectively reduces the volume of the internal fixation and thus reduces the irritation of soft tissues. Plate fixation is more suitable for comminuted fractures of the ulna, especially those containing the olecranon base. Because the broken cortex cannot support each other, whether it is the use of tension band or intramedullary fixation, as long as the internal fixation method of axial compression is involved, it will cause the axial shortening of the ulna and the deformation of the semilunar notch, which will change the size of the opening angle and affect the flexion and extension of the elbow joint.
The fixation of the steel plate and screws can normalize the anatomical reduction of the fracture fragment, especially the use of anatomical compression steel plate, the locking mechanism between the steel plate and the screw can control the fracture fragment as a whole, and avoid the excessive extrusion and displacement of the fracture fragment on the articular surface. Although the use of ulnar olecranon dissecting steel plate can play a good role in fixing and supporting, most of the steel plate design is mainly designed according to foreign populations in clinical practice. The average skeleton of Chinese people is small, and the steel plate often needs to be pre-bent, sometimes the steel plate is installed too high, and even the proximal screw hole needs to be removed during surgery. Postoperatively thin patients have the outline of the subcutaneous plate visible to the naked eye. After the fracture has healed, the patient often requires a second surgery to remove the internal fixation because of the aesthetics or the obvious tactile sensation of the elbow plate.
In summary, olecranon fracture of ulna, as a common clinical elbow injury, brings many challenges to clinicians' surgical selection and patients' postoperative exercise and rehabilitation. At present, there are more and more internal fixation methods for the treatment of ulnar olecranon fractures in clinical practice, but doctors and patients are seeking internal fixation treatments that have less soft tissue damage, firm fixation effect, and are more convenient for early rehabilitation of elbow joint function in the later stage. Although K-wire tension band internal fixation and plate internal fixation are still the mainstream treatment methods in clinical practice, with the development of science and technology, experience and technological innovation, there will be more ideal treatment methods for olecranon fracture of ulna in the future.
Citation: Zhao Sen, Zha Yejun, Gong Maoqi, et al.Advances in the surgical treatment of olecranon fracture of the ulna in adults[J].Journal of Clinical and Research in Orthopedics,2023,8(03):187-190.DOI:10.19548/j.2096-269x.2023.03.012
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