Unstable fractures of the distal radius should be treated by repositioning the articular surface of the distal radius to restore the length of the radius, the palmar inclination of the wrist, and the ulnar deviation angle. The treatment of unstable fractures of the distal radius by means of external fixation in plaster has often failed or had more complications. With the continuous updating of the concept of distal radius fracture treatment, the application of super-articular external fixation frame for distal radius unstable fracture can achieve good repositioning, strong fixation, and less complications, and can obtain better results.
1. Data and methods
1.1 General information There were 37 cases in this group, 21 males and 16 females, aged 18 to 80 years, with an average age of 40 years. There were 2 cases of open fractures. Two cases were combined with ipsilateral distal ulnar fracture and two cases were combined with other fractures of the ipsilateral limb. According to the AO classification: 15 cases of B3 type, 9 cases of C2 type, and 13 cases of C3 type. The causes of injury: 22 cases of falls, 11 cases of traffic injuries, 2 cases of knife injuries, and 2 cases of fall injuries. 23 cases had failed to be fixed in plaster by manipulation. The average time after surgery ranged from 3 hours to 2 weeks, with an average of 7.2 days, and the two open fractures were treated by emergency surgery.
1.2 Surgical method Pre-operative X-ray examination and CT examination were performed if necessary, and pre-operative plan was formulated. The operation was performed in the supine position with the affected limb abducted on a platform that could be visualized by X-ray, with conventional brachial plexus anesthesia or general anesthesia. A small longitudinal incision is made on the dorsal radius of the distal forearm and access is gained through the extensor hallucis longus tendon and the radial extensor carpi radialis longus and shortus, the fracture end is exposed, the bone defect area and dorsally displaced bone fragments are cleared, repositioned, bone grafted, and fixed with kerf pins or/and absorbable screws. The fixation pins were fixed to the base of the second metacarpal and the proximal radial trunk 3-4 cm above the fracture end to restore the radial length and the palmar inclination and ulnar deviation angles, and the external fixation brace was fixed.
1.3 Postoperative treatment Postoperative antibiotics were routinely applied for 3 days, daily needle tract care was performed, rehabilitation training was started on the second day after surgery, and functional exercise of forearm rotation was performed under guidance. 4 weeks after surgery, the spherical joint of the external fixation brace was loosened for dynamization and initial functional exercise of wrist flexion and extension was performed. The external fixation frame can be removed when the X-ray film is reviewed 6-8 weeks after surgery and there is bone scab generation and fracture line blurring.
2.Results
All 31 cases in this group were followed up for 4 to 28 months, with an average of 14 months. The duration of external fixation was 6 to 8 weeks. There were no postoperative nail tract infections, neurovascular injuries, or tendon injuries. The fracture healing time ranged from 6 to 10 weeks, with a mean of 8 weeks. Postoperative radiographic review showed joint surface collapse <2 mm, palmar tilt angle 6°-12°, ulnar deviation angle 15°-25°, and radial longitudinal axis shortening ≤5 mm. treatment results were evaluated according to Dienst [1] functional assessment criteria.
(1) Excellent 18 cases, no pain, no restriction of movement, normal grip strength and less than 15° reduction in extension and flexion;
(2) Good 9 cases with occasional severe pain, limited activity, near normal function, normal grip strength, and 15°-30° reduction in extension and flexion;
(3) 4 cases with frequent pain, mild limitation of activity function, reduced function, reduced grip strength, and reduced extension and flexion by 30° to 50°. The excellent rate was 87.1%.
3. Discussion
Distal radius fractures are common in orthopedics, and unstable fractures of the distal radius are the main indications for surgery, including.
1. dorsal (palmar) cortical comminution of the distal radius and displacement of the articular surface greater than 2 mm;
2. Dorsal inclination of the palmar tilt angle exceeds 20-25°;
3, radial shortening greater than 5mm;
4. The fracture is unstable and prone to re-displacement after repositioning. The fracture is difficult to reset under longitudinal traction, the bone cortex at the fracture end is not satisfactorily supported, and tendons or periosteum are clamped at the fracture end. For severe intra-articular comminuted fractures with significant radial shortening and no effective fixation position for internal fixation screws, external fixation fixation is the preferred method, as in the case of four-part intra-articular fractures. Preoperatively, CT examination should be performed for comminuted fractures, and X-ray examination often cannot correctly determine the severity of the fracture. Xiaoying Gong summarized that there is a large difference between the X-rays and CT measurements in the following items: articular surface compression collapse, articular surface separation, severe articular surface comminution, and radial carpal joint subluxation. In order of importance, the resets are radial length, articular surface flatness, ulnar deviation angle and palmar deviation angle.
The distal radius is located at the convergence of the forearm and wrist, which plays an important role in the function of the forearm and wrist. In the past, the understanding of distal radius fracture was only limited to repositioning, and conservative treatment methods, i.e. closed repositioning, external fixation in plaster or splint, were more often applied. Most of the fracture fragments do not maintain their original repositioned position and are subject to redisplacement. The common complications of conservative treatment are deformity, pain, joint stiffness, and traumatic arthritis.
As the significance of functional and anatomical repositioning of distal radius fractures deepens, the economic level increases and the demand for quality of life improves, the treatment of distal radius fractures also puts forward higher requirements, from favoring improvement of anatomical structure or imaging to improvement of the patient’s subjective symptom efficacy. However, to date, there is no absolutely effective treatment option for distal radius fractures. Surgical options include internal fixation with incision, external fixation, and a combination of internal and external fixation.
The common internal fixation procedures include the application of “T” shaped anatomic splints and distal radius locking splints (LCP). The use of locking compression plates for distal radius fractures is becoming more widely accepted. Musgrave et al. concluded that palmar locking compression plates for distal radius instability fractures can achieve strong internal fixation and early postoperative functional exercise. However, the following problems exist in the internal fixation of the splint: because the distal forearm is superficial, there are a large number of tendons, blood vessels, nerves and ligaments, the splint will stimulate the surrounding tissues, affect the movement of tendons, and even cause tendon adhesions and injuries, which affect the function of the hand and wrist joint; the screws need to be placed carefully, and they are easy to enter the joint cavity; after the fracture heals, the internal fixation needs to be removed by second-stage incision, which is easy to cause injuries again.
External fixation brace fixation restores the normal anatomical structure of the fracture by pulling the surrounding soft tissues such as tendons, supporting bands, periosteum, ligaments, etc. on both sides of the fracture and by providing appropriate traction and firm stability with the external fixation brace. At the same time, the position and angle of the distal fracture block is corrected by adjusting the palmar-dorsal and radial-ulnar directions of the wrist, which expands the single-plane ligament pulling effect and serves to correct the shortening deformity, help the fracture reset, maintain the general contour of the distal radius, and restore the length and force line of the radius. For complex distal radius fractures, when it is difficult to obtain ideal results with simple external fixation, limited incision and repositioning, bone grafting, and internal fixation with Kirschner pins are feasible, which can not only effectively maintain the repositioning and prevent re-displacement of the fracture, but also restore the flatness of the articular surface, so that the crushed distal radius can obtain better anatomical repositioning and prevent the collapse of the articular surface in the middle and late stages, and the patient can get better functional recovery.
The bone graft can be inserted into autologous iliac bone or granulated artificial bone to fill the fracture gap and fill the bone loss at the fracture end, reconstructing the normal mechanical structure of the distal radius, supporting the joint surface, restoring the length of the radius and correcting the palmar and ulnar inclination angles, effectively preventing loss of repositioning and increasing the stability of the fracture end. Autologous iliac bone contains a large amount of osteoconductive and osteoinductive factors, which can promote fracture healing and reduce external fixation time without complications such as rejection. Limited fixation with a Clinique pin provides greater biomechanical stability to the fracture end and continues to stabilize the fracture end when the brace is removed for functional exercise later in the fracture. Lin et al. studied external fixation bracing for distal radius fractures and found that the combined use of Kirschner pins reduced the loss of distal radius length and provided better repositioning and maintenance of reposition. The application of absorbable screw fixation, which can be removed without the need for retraction and is less likely to retract the nail, is superior to the results of kerf pin fixation.
External fixation frames also have complications such as metacarpal fracture, nail loosening, nail tract infection, injury to the superficial branch of the radial nerve, withdrawal of the Kirschner pin, and fracture redisplacement. Our experience is that blunt separation of the cutaneous nerve and tendon tissue before drilling can avoid unnecessary injury; drilling should be performed under direct vision as much as possible, near the base of the 2nd metacarpal, with a thinner fixation nail selected to pass through the double layer of cortex; treatment to improve bone quality should be performed in patients with osteoporosis to prevent nail loosening; absorbable screws should be used for larger bone blocks.
Hyperarticular external fixation has a simple operation; minimally invasive, minimal damage to tendons, blood vessels, nerves and ligaments; can provide lasting traction against forearm muscle squeezing pressure; has adjustable, can change the wrist joint fixation position if necessary; does not require secondary surgery; can be exercised early, good recovery of joint function; can be applied to open fractures; with bone grafting and internal fixation with Kirschner pins/resorbable screws, fixation It is stable, and the possibility of re-displacement and joint surface collapse is small. The treatment of unstable fractures of the distal radius has good efficacy in clinical practice.