Clinical Features and Surgical Strategies of Distal Radius Posttraumatic Deformity.

Objective: To investigate the clinical features and surgical strategies of distal radius posttraumatic deformity.
Methods: A retrospective analysis was performed on the data of 30 patients with distal radius posttraumatic deformity treated by osteotomy and orthopedic surgery in the department of orthopedics, the First Affiliated Hospital of Nanjing Medical University, from February 2016 to November 2018. All the patients underwent preoperative anterior and lateral X-ray plain scanning of bilateral wrist joints, showing different degrees of radius shortening, inferior ulnar and radial mismatch, palmar angle, and ulnar deviation angle, among which 11 patients had an uneven joint surface. After a full evaluation, osteotomy and orthopedic surgery were performed to restore the original anatomical structure, plaster fixation was performed for two weeks after surgery, and regular outpatient follow-up was conducted. The function of the wrist was evaluated by the MMWS (wrist joint improvement) scoring scale before and after surgery, and the changes in the wrist joint-related treatment parameters were evaluated according to X-ray.
Results: All 30 patients had no neurological symptoms after surgery, and all wounds healed within the first stage. All patients were followed up for 6-12 months, with an average healing time of 3.5 months. There was no reduction loss, internal fixation loosening, or fracture in the regular postoperative review. Postoperative MMWS (wrist joint improvement) score scale data were significantly higher than those before surgery, and there were differences between groups (P < 0.05). Postoperative treatment parameters of wrist joints such as palmar inclination angle, ulnar deviation angle, radius height, and lower ulnar and radial matching were significantly improved, and there were differences between groups (P < 0.05). Conclusions: The patients with distal radius posttraumatic deformity have the clinical characteristics of shortening of radius, mismatch of lower ulnar and radius, an abnormal inclination of palm, and ulnar declination. For patients with distal radius posttraumatic deformity, osteotomy and orthopedic surgery can effectively improve wrist function and improve patients' quality of life, which is worthy of clinical reference.

1. Introduction

A distal radius fracture is a common fracture type in orthopedic clinics. The incidence of this fracture is high, accounting for about 20% of total body fractures [1-3], and it is mostly bipolar in age. In the elderly, osteoporosis is mostly low-energy fractures, and in young people, it is mostly high-energy fractures and powdery. Most distal radius fractures can achieve satisfactory treatment results through appropriate treatment in the early stage, but there are still some patients who fail to get the correct treatment in the early stage, leading to the occurrence of posttraumatic deformity.

A distal radius posttraumatic deformity often leads to biomechanical changes of the wrist and functional damage to the hand and forearm, among which ulnar deviation, abnormal palm inclination, and loss of radius height are the most common [4-7]. The posttraumatic deformity is a common complication of distal radius fractures, which can occur in or out of the joint. There are many reasons that can lead to malunion in the process of fracture healing, such as incorrect force lines, joint deformation, insufficient radius height, etc. [7-9].

Biomechanical research shows that the shortening of the radius by 2.5 mm can increase the axial pressure of the ulnar column by 42%. The increase in ulnar pressure often causes TFCC damage and changes the harmony of the lower ulnar and radial joints. At the same time, when the radius is shortened by 10 mm, the pronation and supination functions of the lower ulnar and radial are reduced by 50% and 30%, respectively [10, 11]. Previous studies have also proved that dorsal angulation also transfers the vertical stress of the radiovolar side to the dorsal ulnar side. A 20° angle of dorsal deformity will increase the stress on the ulnar side by 50%, while a 45° angle of dorsal angulation will increase it by 67%. At the same time, due to the mismatch of the lower radioulnar joint, a rotation obstacle and instability of the lower radioulnar joint are caused, resulting in the instability of the radiocarpal joint and the instability of the metacarpophalangeal joint [12]. Similarly, the reduction of the ulnar deflection angle also changes the mechanical distribution of the wrist joint. The mechanical stop of the tendon changes due to the structural changes of the carpal tunnel, which affect the flexion of the finger and reduce the grip strength. At the same time, it changes the distribution of axial force at the distal end of the radius, increasing the force through the lunate fossa [13]. For the elderly with low-energy fractures, the slight unevenness of the articular surface can be tolerated. However, for young people with high-energy fractures, joint steps larger than 1-2 mm will lead to osteoarthritis of the wrist, with very poor clinical results [14, 15].

Therefore, the aim of this study is to explore the clinical characteristics and surgical strategies of posttraumatic deformity of the distal radius, in order to provide guidance for the treatment of posttraumatic deformity of the distal radius in the future.

2. Methods

2.1. Clinical Data

In this retrospective study, 30 patients diagnosed with the distal radius posttraumatic deformity treated in the First Affiliated Hospital of Nanjing Medical University from February 2016 to November 2018 were selected as the research objects. A total of 30 patients were included in this study, including 21 males and 9 females; the age ranged from 16 to 68 years, with an average of 47.5 years. They were all patients with posttraumatic deformities of the distal radius. The time from fracture to operation was 35–95 days, with an average of 59 days.

The study was admitted by the medical ethics committee of Yixing People's Hospital and Jiangsu Province Hospital. All patients had informed consent and signed the informed consent form.

2.2. Inclusion and Exclusion Criteria

Inclusion criteria: (1) patients with posttraumatic deformities of the distal radius confirmed by preoperative imaging data, including radius shortening, lower ulnar radial mismatch, palmar angle, ulnar deviation angle abnormalities, and articular surface irregularities; (2) patients who have no wound infection or damage before operation and whose soft tissue conditions allow internal fixation; (3) patients who have no obvious preoperative contraindications and can tolerate surgery; and (4) complete clinical data.

Exclusion standard: (1) patients with bone tumors, osteogenesis imperfecta, and other diseases; (2) patients with severe osteoporosis; (3) patients who cannot cooperate with rehabilitation treatment after operation; (4) patients with other diseases that affected the postoperative wrist function score in the past; and (5) elderly patients over 70 years old.

2.3. Intervention

All patients were divided into groups of less than 50 days and more than 50 days according to the length of the posttraumatic period. For patients within 50 days after trauma, we give priority to osteotomies along the original fracture line. For patients more than 50 days after trauma, we divided them into simple metaphysis deformity without intra-articular deformity and complex deformity involving the articular surface. For patients with simple metaphyseal deformity without intra-articular deformity, on the basis of dorsal release, a simple arc osteotomy or linear osteotomy is performed at the proximal end of the lower radioulnar joint through the volar approach. The osteotomy line is as close to the articular surface as possible, and the distal bone block of the osteotomy line is enough to place the steel plate. For patients with articular surface deformity, more than two osteotomy lines are often required. Osteotomy is often performed along the original bone fracture line on the articular surface to correct the unevenness of the articular surface, and then the metaphyseal osteotomy is performed at the same time. Before surgery, patients are usually instructed to take necessary functional exercises for 7–10 days, and the softness of soft tissue has been restored.

All patients were placed in the supine position, under brachial plexus anesthesia, with the affected limb abducted on the lateral operating table convenient for fluoroscopy and the tourniquet on 1/3 of the upper arm. Take a longitudinal incision on the radial side of the flexor carpi radialis and cut the skin, subcutaneous tissue, and deep fascia in turn. Blunt separation and entry along the radial flexor carpi and radial artery space exposing the pronator muscle. Protect the radial artery and median nerve and preserve the pronator muscle. The dorsal additional incision is used for soft tissue release and auxiliary reduction, and the dorsal radial column is used for auxiliary fixation when necessary. For patients with a simple metaphyseal deformity without joint deformity, a simple arc osteotomy or linear osteotomy is performed at the proximal end of the lower radioulnar joint. The steel plate at the distal end of the radius is placed as close as possible to the watershed of the articular surface and parallel to the articular surface. The gram needle temporarily fixes the distal bone block of the osteotomy line through the steel plate hole, and the height of the radius and the ulnar deflection angle are adjusted with the help of the steel plate. Then, press the steel plate and stick it to the radial shaft to complete the correction of the palmar angle and bone grafting, if necessary. For patients with articular surface deformity, it is often necessary to perform articular surface osteotomy along the fracture line of the articular surface and then perform radial metaphysis osteotomy to restore the height of the radius, ulnar deviation angle, and palmar inclination after the articular surface is restored. During the operation, fluoroscopy was used to confirm that the relevant measurement data of the patient's wrist joint had been recovered, and then the incision was washed, sutured layer by layer, and wrapped with sterile excipients. Functional exercise should be carried out properly after two weeks of plaster fixation on the affected limb.

2.4. Observation Index

MMWs (wrist joint improvement) rating scale: the patients were followed up at 1 month, 3 months, 6 months, and 12 months after the operation, and the MMWs (wrist joint improvement) score scale data of the patients after treatment were compared, including function, grip strength, activity strength, and pain. Then calculate the total score. The total score is 0–100 points; below 60 points are considered poor, 61–79 points are good, and 80–100 points are excellent.

The treatment parameters of the ulnar deviation angle, palmar inclination angle, lower ulnar radial matching degree, and radial height were observed.

2.5. Statistical Analysis

All data of patients were included in spss22.0 software for summary and processing. The chi-square test was used for the relevant basic data, and the t-test was used for the data of the MMWS (wrist joint improvement) rating scale and treatment parameters. The difference was statistically significant in (X ± s) and P < 0.05.

3. Results

3.1. Clinical Data

A total of 30 patients were included in this study, including 21 males and 9 females; the age ranged from 16 to 68 years, with an average of 47.5 years. They were all patients with the posttraumatic deformity of the distal radius. The time from fracture to operation was 35–95 days, with an average of 59 days. All patients had clinical complaints such as pain and wrist dysfunction, and there was a strong need to improve function. There were various degrees of radial shortening, lower ulnar radial mismatch, palmar angle, ulnar deviation angle abnormalities, and other abnormalities, including 11 cases of joint surface irregularities (Table 1).

Table 1

Clinical characteristics of patients.

	All patients (n = 30)
Age (years)	47.5 ± 7.37
Sex
Male (n%)	21 (70%)
Female (n%)	9 (30%)
BMI (kg/m2)	17.15 ± 2.03
Marital status
Married	13 (43.3%)
Single	6 (20%)
Divorced or separated	6 (20%)
Widowed	3 (10%)
Unknown/missing	2 (6.7%)
Uneven articular surface	11 (36.7%)

3.2. Comparison of MMWS before and after Surgery

All 30 patients had no loss of correction and no neurological symptoms. The wounds healed in one stage. All patients were followed up for 6–12 months, with an average healing time of 3.5 months. No correction loss, internal fixation loosening, or fractures were found in the regular follow-up after the operation. The scores of MMWs (wrist joint improvement) after the operation were significantly higher than those before the operation. There was a difference between the two groups, from 36.72 ± 5.89 before the operation to 83.41 ± 9.29 after the operation (P < 0.05) (Table 2).

Table 2

MMWS (wrist joint improvement) rating scale before and after surgery.

	Function	Grip	Activity	Pain	Total score
Before surgery (n = 30)	8.03 ± 1.56	4.16 ± 0.64	6.38 ± 2.16	13.44 ± 3.25	36.72 ± 5.89
After surgery (n = 30)	22.92 ± 2.73∗	21.64 ± 3.78∗	22.68 ± 3.89∗	20.53 ± 5.05∗	83.41 ± 9.29∗
t	25.94	24.97	20.07	6.47	23.25
P value	<0.05	<0.05	<0.05	<0.05	<0.05

3.3. Comparison of Wrist-Related Treatment Parameters before and after Surgery

The patients after surgery, compared with those before surgery, had a remarkable difference in improvement of palmar inclination, ruler deflection angle, lower ulnar radial matching degree, and radius height, from 1.62 ± 1.32 to 16.73 ± 3.76, 8.03 ± 2.56 to 19.52 ± 3.71, 8.16 ± 2.14 to 1.93 ± 0.91, and 1.52 ± 0.41 to 8.14 ± 3.32, respectively (P < 0.05) (Table 3).

Table 3

Wrist related treatment parameters before and after surgery.

	Palmar inclination	Ruler deflection angle	Lower ulnar radial matching degree (mm)	Radius height (mm)
Before surgery (n = 30)	1.62 ± 1.32	8.03 ± 2.56	8.16 ± 2.14	1.52 ± 0.41
After surgery (n = 30)	16.73 ± 3.76∗	19.52 ± 3.71∗	1.93 ± 0.91∗	8.14 ± 3.32∗
t	20.77	13.97	14.68	10.84
P value	<0.05	<0.05	<0.05	<0.05

3.4. Imaging Manifestation

As shown in Figure 1, the patient had malunion of the left distal radius, shortening of the radius, mismatching of the lower ulna and radius, and significantly abnormal ulnar declination and dorsal inclination. The operation plan was designed according to the contralateral wrist joint before the operation. The operation was performed through a dorsal approach, a volar approach, a simple arc osteotomy of the metaphysis, and a correction of radial height, ulnar deviation, and palmar inclination with the help of a distal radial plate. The wrist deformity and pain disappeared, and the function was significantly improved.

Figure 1

The imaging manifestation. (a) The deformity of the distal radius of the affected side before operation. (b) Anteroposterior and lateral radiographs of the contralateral distal radius joint of the patient. (c) Preoperative plan and intraoperative orthopedic diagram. (d) After deformity correction, the distal radius returned to normal metacarpal angle, ulnar deviation angle, radius height, and lower ulnar radial matching degree. (e) The wrist function of the patient recovered well after the operation.

Furthermore, in the other patients, there was malunion of the right distal radius, shortening of the radius, mismatching of the lower ulna and radius, ulnar deviation, abnormal palmar inclination, and an uneven articular surface. The operation plan was designed according to the contralateral wrist joint before the operation. The combined volar-dorsal approach was selected for the operation. The osteotomy was performed from the volar approach through the articular surface along the original bone fracture line. The articular surface was first restored to be flat, and then the metaphyseal osteotomy was performed. The height of the radius was adjusted, the inclination of the palm and the deviation of the ulna were adjusted, and the plate and screw were fixed. Imaging examination showed that the relevant treatment parameters at the wrist were basically the same as those on the contralateral side. After follow-up, the wrist deformity and pain disappeared, and the wrist function basically returned to normal (Figure 2).

Figure 2

(a) The deformity parameters of the distal radius fracture before operation. (b) Preoperative contralateral normal parameters of patients. (c) Parameters after correction of postoperative deformity. (d) The wrist function after the operation.

4. Discussion

Most patients with posttraumatic deformities of the distal radius have obvious complaints of wrist deformity and wrist dysfunction and have strong surgical demands [7]. Patients with posttraumatic deformity of the distal radius often have complaints of wrist deformity, pain, and limited movement, and often have carpal tunnel syndrome caused by volar bone mass displacement and median nerve compression [9]. It is often seen in imaging that the characteristics of lower ulnar radial mismatch, radial shortening, abnormal ulnar declination/abnormal palmar inclination, and an uneven articular surface seriously affect the function of the wrist joint. Orthopedic surgery can significantly improve these conditions, restore wrist function, and improve the quality of life of patients with the above-mentioned posttraumatic joint deformity of the distal radius [16]. Once the diagnosis of deformity is made and the operation plan is determined, a reasonable osteotomy should be carried out as soon as possible to correct the deformity of the wrist and avoid or reduce the contracture of the soft tissue of the wrist [17]. A reasonable preoperative plan is very important for the correction of the deformity. In addition to the anteroposterior and lateral X-ray of the wrist joint of the affected limb before the operation, it is also necessary to take the anteroposterior and lateral X-ray of the wrist joint of the healthy side as the standard of orthopedics, which is crucial to the formulation of the preoperative plan [18].

In the course of our research, we found that for the malunion of simple fractures with few fracture lines, osteotomy and orthopedic surgery should be performed as early as possible, and osteotomy should be performed along the original fracture line. Early intervention surgery is technically easier and reduces the overall time of disability. However, delayed surgery is also a suitable choice for some special cases, such as severely comminuted fractures. It is best to determine the final treatment plan after the fracture is completely healed, and for such complex fractures with many fracture lines, the restorative line is often the main focus rather than blindly pursuing anatomical repositioning. If there is an uneven articular surface, it is recommended to perform osteotomy and orthopedic surgery as soon as possible to restore the smoothness of the articular surface.

Previous studies have pointed out that correct osteotomy and orthopedics can improve the motion function of the wrist joint and forearm and relieve pain [19], and some studies have pointed out that the osteotomy should pass through the initial fracture line so that the most original fracture block can be reproduced [20]. During our research and observation, we found that for metaphyseal deformities that have not yet fully healed and unevenness caused by articular surface malunion, we give priority to osteotomy along the original fracture line, but for metaphyseal deformities that have been healed for a long time, we can perform arc or linear osteotomy near the articular surface at the proximal end of the lower radius and ulna to ensure that the distal bone block of the osteotomy line is enough to place the steel plate.

In the orthopedic process, the choice of fixation and surgical approach is equally important. With the development of technology, the volar approach for osteotomy and the placement of main plates have become mainstream [21, 22]. However, a dorsal incision is also indispensable. The dorsal approach for soft tissue release is necessary for orthopedic surgery. Patients with complex deformities and multiple osteotomy lines often need dorsal double columns for auxiliary fixation. During our operation, we choose the volar approach as the main approach, supplemented by the dorsal approach. The dorsal approach is mostly used to release soft tissue as the basis of osteotomy and orthopedics. During the operation, the steel plate can be used for auxiliary orthopedic reduction, such as the reduction of ulnar deflection with the help of the compression of the radial column steel plate, the reduction of palmar inclination with the help of the dorsal steel plate, etc.

Bone grafting is often needed to restore the relevant angle and further maintain joint stability during osteotomy and orthopedic surgery for posttraumatic deformities of the distal radius. The commonly used bone grafting method in clinics is structural bone grafting, mainly using iliac bone blocks, fibula, ribs, and allogeneic bone, of which the iliac bone block is the most commonly used. The iliac bone block is rich in cancellous bone, and studies have reported that its bone graft fusion rate is as high as 95%, which is the gold standard for bone defect repair [23]. However, there are still some deficiencies in the iliac bone graft, such as long-term pain and numbness in the bone donor area. Some studies have pointed out that the center of iliac bone mass often has the risk of bone necrosis, absorption, collapse, and displacement due to insufficient blood supply [24]. Nonstructural bone grafting refers to the use of granular bone blocks with a diameter of less than 5 mm for bone grafting, which is simple to prepare and implant and has a high fusion rate [25-27]. The fusion time of patients with nonstructural bone grafting is often shorter than that of structural bone grafting, but the granular bone is looser than the complete iliac bone block, and it is not as durable as the iliac bone block for the maintenance of articular surface and angle. The literature shows that there is no significant difference between structural bone grafting and nonstructural bone grafting for osteotomy and correction of the distal radius deformity [28]. Our experience is similar to the literature. Nonstructural bone grafting has also achieved good clinical results.

A fracture of the styloid process of the ulna is a common injury related to the fracture of the distal radius. 53% of the distal radius fractures are accompanied by ulnar styloid process fractures, and 26% of them often have nonunion [29]. There has been a long debate about whether the fracture of the styloid process of the ulna has an impact on the healing of the fracture of the distal radius. The styloid process of the ulna plays an indispensable role in maintaining the biomechanical stability of the wrist, affecting the pronation and supination functions of the wrist. Found that whether the fracture of the styloid process of the ulna is anatomically reduced or whether it is completely healed has little effect on the improvement of the wrist function. Combined with recent research and our clinical experience, it is found that without affecting the stability of the radioulnar joint and the anatomical reduction of the distal radius, whether the fracture of the styloid process of the ulna is anatomically reduced or completely healed, the wrist function of the patient can recover to a good level after the operation. However, open reduction and internal fixation or reduction with the help of the radioulnar ligament should be used for those with an ulnar styloid process fracture displacement of more than 2 mm at the base and those with an extremely unstable distal radioulnar joint.

Although previous studies have carried out relatively complete research and a summary on the wrist deformity and wrist dysfunction of patients with posttraumatic deformity of the distal radius, there are still few clinical data on the treatment and correction of patients. Our study can supplement some samples and evidence for this field. Our study also has a series of deficiencies, such as too few samples and a follow-up time that is only controlled within one year. These deficiencies need to be corrected by expanding the sample and continuing the follow-up.

In summary, the posttraumatic deformity of the distal radius has its own unique clinical characteristics. Based on the full evaluation of the deformity of the patient combined with the demands of the patient, the deformity should be corrected using the contralateral limb as the template. There should be a detailed preoperative plan and a good osteotomy design. Sufficient soft tissue release is required during the operation. An anatomical steel plate is a powerful tool for intraoperative correction and reduction. Osteotomy and correction of the posttraumatic deformity of the distal radius can effectively improve the function of the wrist joint and significantly improve the quality of life of patients.