Distal Radius Volar Rim Fracture Fixation Using DePuy-Synthes Volar Rim Plate

Abstract

Background To assess the results of distal radius fractures with the involvement of the volar rim fixed with the DePuy-Synthes Volar Rim Plate.

Case Description We searched for the patients with volar rim fracture and/or volar rim fractures as part of a complex fracture fixed with a volar rim plate. Ten patients met the inclusion criteria: three patients with type 23B3, six patients with type 23C, and one patient with very distal type 23A. The mean follow-up was 14 months (range: 2–26). Fractures healed in all patients. Of the three patients with isolated volar rim fractures (type 23B3), two patients had no detectable deficits in motion. These patients had an average Gartland and Werley score of 9 (range: 2–14). Of the other seven patients (six with type 23C and one with type 23A fracture), three patients healed with full range of motion and four had some deficits in range of motion. Two patients had excellent results, three had good results, and two had fair results using the Gartland and Werley categorical rating. One patient healed with a shortened radius and ulnar impingement requiring a second surgery for ulnar head resection arthroplasty.

Literature Review Results after nonoperative treatment of volar rim fractures are not satisfactory and often require subsequent corrective osteotomy. Satisfactory outcomes are achieved when the fragments are well reduced and secured regardless of the device type.

Clinical Relevance Volar rim plates give an adequate buttress of the volar radius distal to volar projection of the lunate facet and do not interfere with wrist mobility. Furthermore, the dorsal fragments can be fixed securely through the volar approach eliminating the need for a secondary posterior incision. However, patients should be informed of the potential problems and the need to remove the plate if symptoms develop.

Coronal splits of the distal radius, or volar rim fractures, are classified as fracture type 23B3 according to the Arbeitsgemeinschaft für Osteosynthesefragen (AO)/Orthopedic Trauma Association (OTA) classifications. These fractures are a subset of unstable distal radius fractures caused by shearing forces.¹ Moreover, fractures involving the volar rim can be part of a complex high-energy impaction fracture. Although these fractures are uncommon, their fixation is required to restore wrist and forearm kinematics.^{2 3} Unlike some fractures of the dorsal rim, volar rim fractures are rarely amenable to closed treatment.⁴ Furthermore, the difference in volar anatomy of the scaphoid and lunate facets increases the complexity of achieving stable fracture fixation if lunate and scaphoid facets are split, predisposing volar lunate fragment displacement with subsequent volar subluxation of the carpus.^{2 5}

The operative technique is chosen based on the size of the fragment and type of fracture. The lunate facet projects anterior to the relatively flat surface of the volar distal radius (Fig. 1A–C). The orientation of the volar lunate rim creates a setup for a triangular fragment that a conventional volar plate is unlikely to capture because the distally directed screws may penetrate the wrist joint. The risk of loss of reduction or failure is increased if the lunate facet fragment is less than 15 mm and the fracture is fixed with a standard volar plate; this situation merits additional fixation techniques.⁶ In addition, some volar rim fractures are not restricted to the volar cortex but extend to the dorsal cortex, creating a complete articular fracture in which a single buttress plate would displace the articular surface dorsally.⁷ For very small fracture fragments, wire loop fixation techniques have been described where a wire is passed through the volar capsule or intercapsular ligaments without disrupting the vasculature and connective tissues around the volar lunate fragment.⁴ Fragment-specific devices have also been tried for comminuted fractures but they require multiple incisions and have a steep learning curve.^{8 9}

Fig. 1.

Three-dimensional reconstruction of distal radius. (A) Sagittal view of the distal radius shows the volar rim projecting upward. (B) This view illustrates the triangular setup of the lunate facet and the volar rim projection. (C) Axial view of the distal radius articular surface shows the scaphoid and lunate facets as well as the volar projection of the volar rim of the lunate facet.

Because of the importance of volar rim fracture reduction and the variety of techniques described, devices are evolving to better address these issues. An ideal device would capture very distal, small fragments without insulting the articular cartilage, be easily learned and applied, and result in excellent patient outcomes. For these reasons a volar rim plate (2.4-mm Variable Angle LCP Volar Rim Distal Radius Plate [VRP], DePuy-Synthes, West Chester, PA) was designed that can be placed past the volar lunate projection with screws directing proximally. In this study, we are reporting our experience with volar rim fractures and the VRP plate and a description of our surgical technique using the VRP.

Methods

Study Design

After we obtained institutional review board approval, we performed a retrospective chart review of all patients with volar rim fractures and/or fractures treated with VRP. We searched the billing records for all intra-articular distal radius fractures in patients older than 18 years who underwent open reduction internal fixation by the senior author (J. B. J.) from 2011 to 2015. We identified 71 patients, and an experienced hand surgeon (A.R.K.) classified the first radiograph of each distal radius fracture according to the AO/OTA Comprehensive Classification. We found 10 patients that met our inclusion criteria: 3 patients with type 23B3 fracture fixed with a 2.4-mm Variable Angle LCP Distal Radius System (VA-LCP; Dupuy-Synthes, West Chester, PA), 6 patients with type 23C fracture fixed with a VRP, and 1 patient with type 23A fixed with a VRP. Of three patients with type 23B3 fracture, two had a large fragment (AO/OTA type 23B3.2) and one had a volar rim fracture with multiple fragments (AO/OTA type 23B3.3). Patient with type 23A had a low-lying extra-articular, distal radius fracture (AO/OTA type 23A2.2) that was fixed using a VRP. The other six patients had a complete articular fracture with the fracture of the volar rim as part of a complex fracture (AO/OTA type 23Cx.x), which were fixed using a VRP (Fig. 2A, B).

Fig. 2.

(A) Lateral radiograph of wrist after a large fragment volar rim fracture, AO/OTA type 23B3.2. (B) Lateral radiograph of the same patient after open reduction internal fixation using VA-LCP. Although it was used to buttress the fragment, the plate did not cover the volar rim.

The average age of the patients was 54 years (range: 23–71). We followed each patient for an average of 14 months (range: 2–26). Nine patients were women who suffered a fall. One patient was a 19-year-old man who suffered a traumatic accident. No patients had clinical distal radioulnar joint instability. All patients with AO/OTA type A and C fractures had associated ulnar styloid process fractures, while no patients with AO/OTA type B fractures had ulnar styloid fractures (Table 1).

Table 1. Characteristics of patients with complex distal radius or volar rim fractures.

	Sex	Age (y)	Side	Injury mechanism	DRUJ instability	Ulnar styloid fracture	AO class	Device	Bone graft	Secondary surgery	Follow-up (mo)	Flexion	Extension	Supination	Pronation	Gartland and Werley scorea
1	Female	55	R	Fall	No	No	B32	VA-LCP	No	No	8.83	30	30	Full	Full	14
2	Female	55	L	Fall	No	No	B33	VA-LCP	No	No	15.25	Full	Full	Full	Full	2
3	Female	41	R	Fall	No	No	B32	VA-LCP	No	No	2.25	Full	Full	Full	Full	11
4	Female	71	L	Fall	No	Yes	C31	VRP	No	No	12.17	35	30	30	40	7
5	Female	60	L	Fall	No	Yes	C21	VRP	No	No	3.83	30	30	Full	Full	8
6	Female	64	L	Fall	No	Yes	C31	VRP	No	Yesb	26.58	Full	Full	30	30	9
7	Female	65	L	Fall	No	Yes	C32	VRP	No	No	8.58	40	40	30	Full	12
8	Female	59	R	Fall	No	Yes	C13	VRP	No	No	48.83	Full	Full	Full	Full	3
9	Female	50	L	Fall	No	Yes	C32	VRP	No	No	16.25	Full	Full	Full	Full	2
10	Male	24	R	Accident	No	Yes	A22	VRP	No	No	1.08	Full	Full	Full	Full	0

Abbreviations: AO, Arbeitsgemeinschaft für Osteosynthesefragen; DRUJ, distal radioulnar joint; L, left; R, right; VA-LCP, 2.4-mm Variable angle LCP distal radius system; VRP, 2.4-mm Variable angle LCP volar rim distal radius plate.

Note: Mean age = 54 years; mean time to follow-up = 14 months.

^aExcellent: 0–2; good: 3–8; fair: 9–20; poor: ≥21.

^bUlnar head resection.

Outcomes

We reviewed the medical record for patient characteristics, an injury description, and the most recent postoperative evaluation. This included a subjective assessment of pain, radiographic examination, and clinical exam. We documented limitations in range of motion in degrees. No patients had signs of nerve entrapment. We used the most recent evaluation to calculate the Garland and Werley functional system score for each patient. The Garland and Werley score is a postoperative assessment tool and a high score indicates worse postoperative outcomes. The scoring system is calculated based on residual deformity, subjective evaluation, objective clinical exam, and other complications.¹⁰

Plate Design Features and Surgical Technique

The 2.4-mm Variable Angle LCP Volar Rim Distal Radius Plate (VRP) was designed for fractures of the volar rim with large fracture fragments or multiple fragments. The distal aspect of the plate sits slightly over the volar rim of the distal radius and shaped to fit the contours of the anatomy of the lunate and scaphoid facets. The orientation of the variable angle screw holes directs the screws in a proximal direction, thus avoiding entrance into the radiocarpal joint. The implant has a radial and ulnar phalange that allows additional fixation of the radial styloid and lunate facet fracture. The proximal straight limb offers a wider hole to permit a screw to be placed to help provisional fixation. The distal and proximal limbs of the plate have small holes for temporary Kirschner wire fixation, while images can confirm the position of the plate and adequacy of the reduction (Fig. 3A–D).

Fig. 3.

(A, B) Anteroposterior and lateral radiographs of a 64-year-old woman with a complex multifragmented distal radius fracture (AO/OTA type 23C3.2) with a rotated volar lunate facet fragment. (C, D) Stable fixation was achieved with a volar rim plate.

For operative fixation using the VRP, a standard volar approach to the wrist was used. The incision was made just radial to the flexor carpi radialis. The pronator quadratus was dissected to expose the volar side of the radius. In all cases, the fracture was anatomically reduced, and the reduction and VRP were held in place with a Kirschner wire through the designated holes in the plate. A hole was then drilled through the wider hole using the drill guide and a self-tapping cortex screw was placed. The screw was tightened enough to hold the VRP in place and then the designated holes were drilled for the variable angle screws using the variable angle drill guide. Care was taken not to drill at an angle greater than 15 degrees from the drill hole axis while still drilling through the fracture fragment and intact bone. Each screw was tightened gently at first. After drilling all holes and placing all locking screws, the Kirschner wire was removed and anatomic reduction and plate position were verified using fluoroscopy before tightening all screws (Fig. 4A–G).

Fig. 4.

A very distal intra-articular fracture in a 35-year-old man that was secured stable with the VRP (case courtesy of Dr. Juan Del Pino). (A–C) Coronal and sagittal cuts of the computed tomography scan of the distal articular fracture. (D) Intraoperative illustration of the fracture. (E) Intraoperative illustration of the internal fixation. (F, G) Stable fixation achieved with the VRP.

Results

In this cohort, all volar rim fractures (AO/OTA type 23B3), simple radius fracture (AO/OTA type 23A2.2), and complete articular fractures (AO/OTA type 23C.x) healed.

Of the three patients with isolated volar rim fractures (type 23B3) that were fixed with VA-LCP, two patients had no detectable deficits on clinical exam or radiograph. One patient with a large fragment volar rim fracture (AO/OTA type B3.2) healed with limited flexion and extension, 30 degrees in palmar and dorsiflexion after 9-month follow-up. These patients had an average Gartland and Werley score of 9 and ranged between 2 and 14. One patient (AO/OTA type 23B3.3) had an excellent outcome and two (AO/OTA type 23B3.2) had fair outcomes after treatment, as scored by the Gartland and Werley categorical rating (Table 1).

Other seven patients (six with type 23C and one with type 23A fracture) had fractures fixed with a VRP. Three patients healed with full range of motion and four had some deficits in range of motion. Two patients had excellent results, three had good results, and two had fair results using the Gartland and Werley categorical rating. One patient healed with a shortened radius and ulnar impingement requiring a second surgery for ulnar head resection arthroplasty.

Discussion

Volar rim fractures are uncommon in isolation and may be accompanied by dorsal extension of the fracture line.^{2 11} We only studied the outcomes in the practice of a single surgeon, which may not be generalizable. Some patients did not have a sufficient length of follow-up but they all exhibited satisfactory outcome at the last available visit. We believe these patients' Gartland Werley scores would not decrease with further follow-up and rehabilitation.

The volar plate discussed here is designed to extend distal to the watershed area. This design feature allows the variable angle locking screws to capture distal fragments with low risk of failure. None of our seven patients treated with VRP experienced loss of reduction. This implant can be used with all low-lying distal radius fracture, including types 23A, 23B, and 23C, where achieving anatomic reduction and preserving the joint surface are challenging with a more traditional plate. Our patients treated with VRP had Gartland and Werley categorical rating from fair to excellent with the majority in the good range and no poor outcome, suggesting that VRP offers a promising solution to very distal, intra-articular radius fractures.

Results after nonoperative treatment of volar rim fractures are not satisfactory and often require subsequent corrective osteotomy.^{1 3 12} The results of surgical treatment of OTA type B3 fracture are comparable to OTA types A and C. This suggests satisfactory outcomes are achieved when the fragments are well reduced and secured regardless of the device type.^{1 13} Quantitative three-dimensional computed tomography studies have shown that 16% of the lunate facet project anteriorly from the flat surface of the radius. This bony projection has a mean thickness of 5 mm and width of 19 mm. Its small size makes it difficult to secure when fractured.¹⁴ In addition, a small volar fragment is the only known predictor of fixation failure and volar carpal subluxation after fixation. The risk of failure is greatest when the initial subsidence is greater than 5 mm or volar fragment is less than 15 mm in length.⁶ Small fragments can also rotate. Penetrating devices including Kirschner wire or screws may fragment or devascularize the fractured fragment, while conventional buttress plates are unable to secure the fragment. For these rotationally unstable fragments, wire loop technique is an alternative option with satisfactory results.⁴ The VRP described here and surgical technique offers another solution for isolated volar rim fractures and fractures with the involvement of the volar rim as part of a complex fracture. It yields satisfactory postsurgical outcomes, catches distal fracture fragments, preserves articular cartilage, and is easy to use.

In our experience, volar rim plates give an adequate buttress of the volar radius distal to volar projection of the lunate facet and do not interfere with wrist mobility. Furthermore, the dorsal fragments can be fixed securely through the volar approach eliminating the need for a secondary posterior incision. However, patients should be informed of the potential problems with the implants going over the distal volar rim including tendon irritation, interference with wrist motion, and intra-articular penetration of the screws, and thus the need to remove the implant if symptoms develop.