The use of phalangeal plate as “hook plate” and external fixation to treat complex distal radius fracture fragments

Xiang-feng Zhang, Edem Prince Ghamor-Amegavi, He-jia Hu, Gang Feng

Department of Orthopedic Surgery, the Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou 310009, China

Corresponding Author: Gang Feng, Email:gangfeng@zju.edu.cn

Distal radius fracture is the most common fracture site of the human skeletonand often occurs in young people resulting from high energy injury caused by severe trauma. However, complex distal radial intraarticular fractures (AO type C3) are relatively rare and account for about 5% of all distal radius fractures.Fracture comminution at the joint surface is the primary manifestation of these fractures, followed by avulsion of the bone fragments with displacement seen at both the metacarpal and ulnar bone. Treatment of these displaced and unstable fractures remains a challenge. The nature of the articular surface fracture indicates the use of either the open or close reduction technique. Treatment protocols focus on extra-articular reduction and restoration of radial length, maintaining the volar tilt.It has been noted that incongruity of the intra-articular distal radius fracture is relevant to the development of arthritis.

Surgical methods and instruments such as the band wire technique,the volar plate,and Kirshner wireshave been used to fix the distal bone fragments mainly on the metacarpal and ulnar side, which have achieved good results but still have drawbacks. For fragments less than 5 mm, the method of fixation is limited. On the other hand, the traditional palmar anatomic locking plate provides good support at the comminuted fragments but does not exceed the watershed. Moreover, the distal fractures are often far distal to the watershed and cannot be well fixed.

Recognizing the limitations mentioned above, we report a modified technique in the treatment of AO type C3 distal radius fracture. We first installed an external fixator, and then used a small phalangeal plate contoured as a “hook plate” to provide an additional buttress for small fragments with ligament repair to achieve a good functional outcome. This technique provides a better choice for the treatment of displaced, unstable, and comminuted fracture of the distal radius.

We believe the application of external fixation with this proposed modification of the plate in the treatment of comminuted distal radius fracture will produce good clinical and radiographic outcomes.

METHODS

This study was approved by our hospital’s ethic committee board and informed consent was obtained from all individual participants. Between June 2016 and October 2017, seven patients presenting with AO type C3 distal radius fracture were treated at our department. The study included six men and one female with a median age of 45 years (range: 24-65 years). Four patients had fracture on the right hand and three on the left hand, and all of them were closed injuries. The causes of injury were falls (4 cases) and traffic accident (3 cases). In all the subjects preoperative X-ray and CT radiographic images (Figure 1) were taken, followed by manipulative reduction and immobilization with cast.

Surgical technique

Surgical treatment involved using external fixator first then followed by contoured phalangeal plate in form of a hook. The fractures were reduced by anterior modified radial flexor carpal approach combined with posterior approach depending on the fracture morphology.

After the induction of anesthesia and placement of arm tourniquet, a standard external fixator (Orthofix, Italy) was placed across the radiocarpal joint with incision at the base of the second metacarpal and dorsal side of the radius (away from the estimated placement area of the plate) with enough traction distance. The external fixator stents were placed at an oblique angle of 45° to each other. Manual adjust reduction was done and alignment confirmed by intraoperative fluoroscopy.

Then a modified radial flexor carpi approach about a 4 cm incision was made at the wrist joint space. The distal radius bone was exposed along the radial side of the flexor carpi radialis tendon. The distal ulnar was explored to the distal radioulnar joint about 3 cm from the articular surface. The fracture fragments were exposed and soft tissues were cleared and irrigated. Temporal fixation of the radius styloid process and bone fragments were done with the Kirschner wire. Depending on the fracture site, appropriate phalangeal plate (Synthes Inc., Switzerland) length was contoured to form a hook (the plate has a small notch with the front bent, Figure 2A). The contoured plate was placed on the fractured site and screw applied at the proximal end for eccentric compression and fixation. Here the radius styloid process fracture fragments were conveniently fixed with the “hook plate”. Verification for the placement of the plate on fluoroscopy was made (Figure 2D). Additional contoured plate was placed when needed. In subjects where preoperative CT confirmed dorsal ulnar bone fragments, a dorsal incision approach was used to access the fragments.

Postoperative evaluation

After surgery, all patients were closely followed up. The average period of follow-up was 26 months. The external fixator was maintained for six weeks, and during this period passive and active finger movement was encouraged. After removal of the external fixator, wrist joint movement was emphasized for four weeks. Pain, hand grip strength (HGS) and range of active motion (ROM) were measured and recorded. Postoperative X-ray and CT imaging (Figure 3) were used to observe articular surface recovery, palmar inclination, ulnar deviation and radial shortening on each visit. To assess the functional outcome of the surgery, we used the Mayo wrist score and the Gartland and Werley wrist score, and compared at 3 months and 12 months consecutively postoperation. We reviewed radiographs for fracture healing during follow-up (3-24 months).

RESULTS

Figure 1. Case illustration; two patients (A & B) with comminuted AO type C3 left distal radius fracture with distal volar lunate facet/volar rim fragment, A-P views A (i) and B (i). Lateral X-ray shows intra-articular displacement and comminution A (ii) and B (ii). CT scan image indicates the small fragment and loss of volar inclination and dorsal comminution A (iii,iv) and B (iii,iv).

Figure 2. Surgical procedure. Phalangeal plate contoured into a “hook plate” (A). Temporal fixation of fragments with K-wire (B) followed with internal fixation with plate and screw (C & D).

The average follow-up was 26 months. All patients achieved anatomic reduction and fracture healing (till about 6 months). No complication such as implant failure and wound infection occurred. Six patients recovered well and returned to their daily work and life during the two-year follow-up. One patient could not return to previous job due to the spine injury which resulted in paraplegia. In general, their wrist motion was significantly improved and was similar to the uninjured wrist (HGS ＞90% of normal). Five patients had their internal fixators removed. All the seven patients were satisfied with the current wrist function and had a good mobility (ROM ＞92% of normal, supplementary Figure 1). However, one patient had a minor stretch sensation when flexing the thumb due to scar formation at the radius point where the external fixator was placed and then relieved seven months after operation. The Mayo wrist scored reached 87.5 and that of the Gartland and Werley score was excellent at the end of 12-month follow-up (Table 1).

DISCUSSION

AO type C3 distal radius fracture involves the articular joint with fracture of the volar lunate facet, die punch, dorsal ulnar and radial styloid fragments.The fracture line is often located between the tendon and bone space which manifests with the disruption of the articular bones and connecting ligaments. However, it is difficult for precise reconstruction and repairment of the associated ligament and restoration the volar-ulnar and dorsal-ulnar bone fragments, resulting in palmar subluxation and dislocation of the radioulnar joint. For distal radius fragments, open reduction and external fixation with volar hook plate and screws have been proposedto provide good stability. However, for fragments less than 5 mm the use of this plate is limited.

Table 1. Presentation of Mayo wrist score and Gartland and Werley score at 3 months and 12 months of follow-up

In this study, we propose a technical modification by using phalangeal plate bent at one end to form a hook that provides buttress for fragments and fix tendons attached to bone edges of the distal radius fracture with the external fixator. The first installation of the external fixator did not only provide adequate reduction but also allow easy access to the fragments without disruption of the surrounding ligaments. The secured external fixator also enhanced stability at the distal dorsal fragments to resist displacement. Our patients achieved articular congruity and had satisfactory wrist function and ROM compared to their uninjured wrist. Final follow-up in our study showed no decompression of the median nerve. Our patients had a mean Gartland and Werley wrist score of 2.86 at the end of the 12-month follow-up, indicating excellent outcome with minimal to no impairment to their daily life. Six patients reported fair results while one patient had a good score at three months. At the end of 12 months of follow-up, the Mayo wrist score was good for 3 patients and excellent for 4 patients. On the other hand, objective evaluation of the wrist using Mayo wrist score for the first 3 months with an average score of 58.6 indicating a poor outcome (poor in 6 patients, satisfactory in 1 patient); however, at 12 months, an average score of 87.5 was reported which showed an overall good functional outcome with 3 patients having an excellent score and 4 patients having a good score.

Figure 3. Postoperative radiographic follow-up of two patients (A and B) after treatment with external fixator and “hook” plate. Control CT scan view A (i) and B (i). A-P X-ray views A (ii) and B (ii). Lateral X-ray views A (iii) and B (iii) indicated articular congruity, restoration of radial length and stabilization of the fracture fragments. A (iv, v) and B (iv, v) showed healing of bone after internal removal. CT: computed tomography; AP: anterior-posterior; L: lateral.

The short-term functional recovery rate and score were low in the 3 months after surgery. This could be attributed to the long-term placement of the external fixator which provided discomfort. A close followup and rehabilitation training was emphasized after the removal of external fixator. It has been reported that patients treated with the combined volar plate and external fixation have about 14% complication rateand 19% hardware tendon irritation.However, our study reported no complication by the end of the followup. The advantage of this technique are as follows. (1) As a form of buttress, plate provides palmar support to prevent dislocation of the wrist joint. (2) The distal bending hook can grab and stabilize fragments well and maintain the position of bone block. It has a good off set position for the longitudinal and lateral tension to avoid displacement. (3) Because the plate has a small notch and the front is bent, it helps avoid local sharp protrusion that directly irritates the surround tendons and soft tissues. It is advisable to avoid the use of large plates as this requires extensive separation of the proximal soft tissues and also avoid further dissection of the pronator muscles to reduce postoperation complication. The number of patients in this study is limited. Randomized controlled studies to observe the prognosis of this type of fracture patients is needed.

CONCLUSION

In a summary, we provided a modified technique in treating AO type C3 distal radius fracture. The use of this surgical approach and fixation is effective and provides better option to overcome the challenges in treating these types of unstable comminuted fractures.

Funding: Not applicable.

Ethics approval: This study was approved by the ethic committee board of the Second Affiliated Hospital of Zhejiang University School of Medicine and in compliance with ethical standards. Written informed consent was obtained from each patient for this publication and accompanying images.

Conflicts of interests: The authors have no conflicts of interest to declare that are relevant to the content of this article.

Contributors: XFZ, member of surgical team, carried out study proposal recorded and analyzed patients’ progress before and after surgical intervention. EPGA, member of surgical team, recorded and analyzed patient’s progress before and after surgical intervention. HJH, member of surgical team, collected research data and analyzed literature study. GF, leader of surgical team, guided the operation plan and the control of the whole process, revised the manuscript.

All the supplementary files in this paper are available at http://wjem.com.cn.